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1.
  • Bufano, Filomena, et al. (author)
  • THE HIGHLY ENERGETIC EXPANSION OF SN 2010bh ASSOCIATED WITH GRB 100316D
  • 2012
  • In: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 753:1, s. 67-
  • Journal article (peer-reviewed)abstract
    • We present the spectroscopic and photometric evolution of the nearby (z = 0.059) spectroscopically confirmed Type Ic supernova, SN 2010bh, associated with the soft, long-duration gamma-ray burst (X-ray flash) GRB 100316D. Intensive follow-up observations of SN 2010bh were performed at the ESO Very Large Telescope (VLT) using the X-shooter and FORS2 instruments. Thanks to the detailed temporal coverage and the extended wavelength range (3000-24800 angstrom), we obtained an unprecedentedly rich spectral sequence among the hypernovae, making SN 2010bh one of the best studied representatives of this SN class. We find that SN 2010bh has a more rapid rise to maximum brightness (8.0 +/- 1.0 rest-frame days) and a fainter absolute peak luminosity (L-bol approximate to 3 x 10(42) erg s(-1)) than previously observed SN events associated with GRBs. Our estimate of the ejected Ni-56 mass is 0.12 +/- 0.02 M-circle dot. From the broad spectral features, we measure expansion velocities up to 47,000 km s(-1), higher than those of SNe 1998bw (GRB 980425) and 2006aj (GRB 060218). Helium absorption lines He I lambda 5876 and He I 1.083 mu m, blueshifted by similar to 20,000-30,000 km s(-1) and similar to 28,000-38,000 km s(-1), respectively, may be present in the optical spectra. However, the lack of coverage of the He I 2.058 mu m line prevents us from confirming such identifications. The nebular spectrum, taken at similar to 186 days after the explosion, shows a broad but faint [O I] emission at 6340 angstrom. The light curve shape and photospheric expansion velocities of SN 2010bh suggest that we witnessed a highly energetic explosion with a small ejected mass (E-k approximate to 10(52) erg and M-ej approximate to 3 M-circle dot). The observed properties of SN 2010bh further extend the heterogeneity of the class of GRB SNe.
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2.
  • Bose, Subhash, et al. (author)
  • Gaia17biu/SN 2017egm in NGC 3191 : The Closest Hydrogen-poor Superluminous Supernova to Date Is in a Normal, Massive, Metal-rich Spiral Galaxy
  • 2018
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 853:1
  • Journal article (peer-reviewed)abstract
    • Hydrogen-poor superluminous supernovae (SLSNe-I) have been predominantly found in low-metallicity, star-forming dwarf galaxies. Here we identify Gaia17biu/SN 2017egm as an SLSN-I occurring in a normal spiral galaxy (NGC 3191) in terms of stellar mass (several times 10(10) M-circle dot) and metallicity (roughly solar). At redshift z = 0.031, Gaia17biu is also the lowest-redshift SLSN-I to date, and the absence of a larger population of SLSNe-I in dwarf galaxies of similar redshift suggests that metallicity is likely less important to the production of SLSNe-I than previously believed. With the smallest distance and highest apparent brightness for an SLSN-I, we are able to study Gaia17biu in unprecedented detail. Its pre-peak near-ultraviolet to optical color is similar to that of Gaia16apd and among the bluest observed for an SLSN-I, while its peak luminosity (M-g = -21 mag) is substantially lower than that of Gaia16apd. Thanks to the high signal-to-noise ratios of our spectra, we identify several new spectroscopic features that may help to probe the properties of these enigmatic explosions. We detect polarization at the similar to 0.5% level that is not strongly dependent on wavelength, suggesting a modest, global departure from spherical symmetry. In addition, we put the tightest upper limit yet on the radio luminosity of an SLSN-I with < 5.4 x 10(26) erg s(-1) Hz(-1) at 10 GHz, which is almost a factor of 40 better than previous upper limits and one of the few measured at an early stage in the evolution of an SLSN-I. This limit largely rules out an association of this SLSN-I with known populations of gamma-ray-burst-like central engines.
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3.
  • Hosseinzadeh, Griffin, et al. (author)
  • Type Ibn Supernovae Show Photometric Homogeneity and Spectral Diversity at Maximum Light
  • 2017
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 836:2
  • Journal article (peer-reviewed)abstract
    • Type Ibn supernovae (SNe) are a small yet intriguing class of explosions whose spectra are characterized by low-velocity helium emission lines with little to no evidence for hydrogen. The prevailing theory has been that these are the core-collapse explosions of very massive stars embedded in helium-rich circumstellar material (CSM). We report optical observations of six new SNe Ibn: PTF11rfh, PTF12ldy, iPTF14aki, iPTF15ul, SN 2015G, and iPTF15akq. This brings the sample size of such objects in the literature to 22. We also report new data, including a near-infrared spectrum, on the Type Ibn SN 2015U. In order to characterize the class as a whole, we analyze the photometric and spectroscopic properties of the full Type Ibn sample. We find that, despite the expectation that CSM interaction would generate a heterogeneous set of light curves, as seen in SNe IIn, most Type Ibn light curves are quite similar in shape, declining at rates around 0.1 mag day(-1) during the first month after maximum light, with a few significant exceptions. Early spectra of SNe Ibn come in at least two varieties, one that shows narrow P Cygni lines and another dominated by broader emission lines, both around maximum light, which may be an indication of differences in the state of the progenitor system at the time of explosion. Alternatively, the spectral diversity could arise from viewing-angle effects or merely from a lack of early spectroscopic coverage. Together, the relative light curve homogeneity and narrow spectral features suggest that the CSM consists of a spatially confined shell of helium surrounded by a less dense extended wind.
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4.
  • Hosseinzadeh, Griffin, et al. (author)
  • Weak Mass Loss from the Red Supergiant Progenitor of the Type II SN 2021yja
  • 2022
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 935:1
  • Journal article (peer-reviewed)abstract
    • We present high-cadence optical, ultraviolet (UV), and near-infrared data of the nearby (D approximate to 23 Mpc) Type II supernova (SN) 2021yja. Many Type II SNe show signs of interaction with circumstellar material (CSM) during the first few days after explosion, implying that their red supergiant (RSG) progenitors experience episodic or eruptive mass loss. However, because it is difficult to discover SNe early, the diversity of CSM configurations in RSGs has not been fully mapped. SN 2021yja, first detected within approximate to 5.4 hours of explosion, shows some signatures of CSM interaction (high UV luminosity and radio and x-ray emission) but without the narrow emission lines or early light-curve peak that can accompany CSM. Here we analyze the densely sampled early light curve and spectral series of this nearby SN to infer the properties of its progenitor and CSM. We find that the most likely progenitor was an RSG with an extended envelope, encompassed by low-density CSM. We also present archival Hubble Space Telescope imaging of the host galaxy of SN 2021yja, which allows us to place a stringent upper limit of less than or similar to 9 M-circle dot; on the progenitor mass. However, this is in tension with some aspects of the SN evolution, which point to a more massive progenitor. Our analysis highlights the need to consider progenitor structure when making inferences about CSM properties, and that a comprehensive view of CSM tracers should be made to give a fuller view of the last years of RSG evolution.
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6.
  • Meroni, Marica, et al. (author)
  • Mboat7 down-regulation by hyper-insulinemia induces fat accumulation in hepatocytes.
  • 2020
  • In: EBioMedicine. - : Elsevier BV. - 2352-3964. ; 52
  • Journal article (peer-reviewed)abstract
    • Naturally occurring variation in Membrane-bound O-acyltransferase domain-containing 7 (MBOAT7), encoding for an enzyme involved in phosphatidylinositol acyl-chain remodelling, has been associated with fatty liver and hepatic disorders. Here, we examined the relationship between hepatic Mboat7 down-regulation and fat accumulation.Hepatic MBOAT7 expression was surveyed in 119 obese individuals and in experimental models. MBOAT7 was acutely silenced by antisense oligonucleotides in C57Bl/6 mice, and by CRISPR/Cas9 in HepG2 hepatocytes.In obese individuals, hepatic MBOAT7 mRNA decreased from normal liver to steatohepatitis, independently of diabetes, inflammation and MBOAT7 genotype. Hepatic MBOAT7 levels were reduced in murine models of fatty liver, and by hyper-insulinemia. In wild-type mice, Mboat7 was down-regulated by refeeding and insulin, concomitantly with insulin signalling activation. Acute hepatic Mboat7 silencing promoted hepatic steatosis in vivo and enhanced expression of fatty acid transporter Fatp1. MBOAT7 deletion in hepatocytes reduced the incorporation of arachidonic acid into phosphatidylinositol, consistently with decreased enzymatic activity, determining the accumulation of saturated triglycerides, enhanced lipogenesis and FATP1 expression, while FATP1 deletion rescued the phenotype.MBOAT7 down-regulation by hyper-insulinemia contributes to hepatic fat accumulation, impairing phosphatidylinositol remodelling and up-regulating FATP1.LV was supported by MyFirst Grant AIRC n.16888, Ricerca Finalizzata Ministero della Salute RF-2016-02,364,358, Ricerca corrente Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico; LV and AG received funding from the European Union Programme Horizon 2020 (No. 777,377) for the project LITMUS-"Liver Investigation: Testing Marker Utility in Steatohepatitis". MM was supported by Fondazione Italiana per lo Studio del Fegato (AISF) 'Mario Coppo' fellowship.
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7.
  • Singh, Mridweeka, et al. (author)
  • The Fast-evolving Type Ib Supernova SN 2015dj in NGC 7371
  • 2021
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 909:2
  • Journal article (peer-reviewed)abstract
    • We present the detailed optical evolution of a Type Ib SN 2015dj in NGC 7371, using data spanning up to similar to 170 days after discovery. SN 2015dj shares similarity in light-curve shape with SN 2007gr and peaks at M-V = -17.37 +/- 0.02 mag. Analytical modeling of the quasi bolometric light curve yields 0.06 +/- 0.01 M-circle dot of Ni-56, ejecta mass = M-ej = 1.4(-0.5)(+1.3) M-circle dot, and kinetic energy E-k = 0.7(-0.3)(+0.6) x 10(51) erg. The spectral features show a fast evolution and resemble those of spherically symmetric ejecta. The analysis of nebular phase spectral lines indicates a progenitor mass between 13-20 M-circle dot, suggesting a binary scenario.
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8.
  • Stefania, Grimaudo, et al. (author)
  • PCSK9 rs11591147 R46L Loss-of-Function Variant Protects Against Liver Damage in Individuals with NAFLD.
  • 2021
  • In: Liver international : official journal of the International Association for the Study of the Liver. - : Wiley. - 1478-3231. ; 41:2, s. 321-332
  • Journal article (peer-reviewed)abstract
    • The proproteinconvertasesubtilisin/kexin type 9(PCSK9) plays a key role in cholesterol homeostasis, and its inhibition represents an effective therapy to lower LDL-C levels. In this study, we examined the impact of the PCSK9 rs11591147 loss-of-function (LOF) variant on liver damage in a multicenter collection of patients at risk of nonalcoholic steatohepatitis (NASH), in clinical samples and experimental models.We considered 1,874 consecutive individuals at risk of NASH as determined by histology. The SNP rs11591147, encoding for the p.R46L variant of PCSK9,was genotyped by TaqMan assays. We also evaluated 1)PCSK9 mRNA hepatic expression in human liver, and 2)the impact of a NASH-inducing diet in mice with hepatic overexpression of human PCSK9.Carriers of PCSK9 rs11591147 had lower circulating LDL-C levels and were protected against NAFLD (OR0.42; 95%C.I0.22-0.81; P=0.01), NASH (OR0.48;95%C.I.0.26-0.87;P=0.01)and more severe fibrosis (OR0.55; 95%C.I.0.32-0.94; P=0.03) independently of clinical, metabolic and genetic confounding factors. PCSK9 hepatic expression was directly correlated with liver steatosis(P=0.03). Finally, liver-specific overexpression of human PCSK9 in male mice drives NAFLD and fibrosis upon a dietary challenge.In individuals at risk of NASH, PCSK9 was induced with hepatic fat accumulation and PCSK9 rs11591147 LOF variant was protective against liver steatosis, NASH and fibrosis, suggesting PCSK9 inhibition may be a new therapeutic strategy to treat NASH.
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9.
  • Valenti, Stefano, et al. (author)
  • A SPECTROSCOPICALLY NORMAL TYPE Ic SUPERNOVA FROM A VERY MASSIVE PROGENITOR
  • 2012
  • In: The Astrophysical Journal Letters. - 2041-8205. ; 749:2, s. L28-
  • Journal article (peer-reviewed)abstract
    • We present observations of the Type Ic supernova (SN Ic) 2011bm spanning a period of about one year. The data establish that SN 2011bm is a spectroscopically normal SN Ic with moderately low ejecta velocities and with a very slow spectroscopic and photometric evolution (more than twice as slow as SN 1998bw). The Pan-STARRS1 retrospective detection shows that the rise time from explosion to peak was similar to 40 days in the R band. Through an analysis of the light curve and the spectral sequence, we estimate a kinetic energy of similar to 7-17 foe and a total ejected mass of similar to 7-17 M-circle dot, 5-10 M-circle dot of which is oxygen and 0.6-0.7 M-circle dot is Ni-56. The physical parameters obtained for SN 2011bm suggest that its progenitor was a massive star of initial mass 30-50 M-circle dot. The profile of the forbidden oxygen lines in the nebular spectra shows no evidence of a bi-polar geometry in the ejected material.
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10.
  • Arcavi, Iair, et al. (author)
  • Energetic eruptions leading to a peculiar hydrogen-rich explosion of a massive star
  • 2017
  • In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 551:7679, s. 210-213
  • Journal article (peer-reviewed)abstract
    • Every supernova so far observed has been considered to be the terminal explosion of a star. Moreover, all supernovae with absorption lines in their spectra show those lines decreasing in velocity over time, as the ejecta expand and thin, revealing slower-moving material that was previously hidden. In addition, every supernova that exhibits the absorption lines of hydrogen has one main light-curve peak, or a plateau in luminosity, lasting approximately 100 days before declining(1). Here we report observations of iPTF14hls, an event that has spectra identical to a hydrogen-rich core-collapse supernova, but characteristics that differ extensively from those of known supernovae. The light curve has at least five peaks and remains bright for more than 600 days; the absorption lines show little to no decrease in velocity; and the radius of the line-forming region is more than an order of magnitude bigger than the radius of the photosphere derived from the continuum emission. These characteristics are consistent with a shell of several tens of solar masses ejected by the progenitor star at supernova-level energies a few hundred days before a terminal explosion. Another possible eruption was recorded at the same position in 1954. Multiple energetic pre-supernova eruptions are expected to occur in stars of 95 to 130 solar masses, which experience the pulsational pair instability(2-5). That model, however, does not account for the continued presence of hydrogen, or the energetics observed here. Another mechanism for the violent ejection of mass in massive stars may be required.
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11.
  • Baselli, G. A., et al. (author)
  • Liver transcriptomics highlights interleukin-32 as novel NAFLD-related cytokine and candidate biomarker
  • 2020
  • In: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 69, s. 1855-1866
  • Journal article (peer-reviewed)abstract
    • Objective: Efforts to manage non-alcoholic fatty liver disease (NAFLD) are limited by the incomplete understanding of the pathogenic mechanisms and the absence of accurate non-invasive biomarkers. The aim of this study was to identify novel NAFLD therapeutic targets andbiomarkers by conducting liver transcriptomic analysis in patients stratified by the presence of the PNPLA3 I148M genetic risk variant. Design: We sequenced the hepatic transcriptome of 125 obese individuals. 'Severe NAFLD' was defined as the presence of steatohepatitis, NAFLD activity score ≥4 or fibrosis stage ≥2. The circulating levels of the most upregulated transcript, interleukin-32 (IL32), were measured by ELISA. Results: Carriage of the PNPLA3 I148M variant correlated with the two major components of hepatic transcriptome variability and broadly influenced gene expression. In patients with severe NAFLD, there was an upregulation of inflammatory and lipid metabolism pathways. IL32 was the most robustly upregulated gene in the severe NAFLD group (adjusted p=1×10-6), and its expression correlated with steatosis severity, both in I148M variant carriers and non-carriers. In 77 severely obese, and in a replication cohort of 160 individuals evaluated at the hepatology service, circulating IL32 levels were associated with both NAFLD and severe NAFLD independently of aminotransferases (p<0.01 for both). A linear combination of IL32-ALT-AST showed a better performance than ALT-AST alone in NAFLD diagnosis (area under the curve=0.92 vs 0.81, p=5×10-5). Conclusion: Hepatic IL32 is overexpressed in NAFLD, correlates with hepatic fat and liver damage, and is detectable in the circulation, where it is independently associated with the presence and severity of NAFLD. © 2020 American Medical Association. All rights reserved.
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12.
  • Baselli, Guido A, et al. (author)
  • Rare ATG7 genetic variants predispose patients to severe fatty liver disease.
  • 2022
  • In: Journal of hepatology. - : Elsevier BV. - 1600-0641 .- 0168-8278. ; 77:3, s. 596-606
  • Journal article (peer-reviewed)abstract
    • Nonalcoholic fatty liver disease (NAFLD) is the leading cause of liver disorders and has a strong heritable component. The aim of this study was to identify new loci contributing to severe NAFLD by examining rare variants.We performed whole-exome sequencing in individuals with NAFLD and advanced fibrosis or hepatocellular carcinoma (n=301) and examined the enrichment of likely pathogenic rare variants vs. the general population, followed by validation at gene level.In patients with severe NAFLD, we observed an enrichment of the p.P426L variant (rs143545741 C>T; OR 5.26, 2.1-12.6; p=0.003) of autophagy-related 7 (ATG7), which we characterized as a loss-of-function, vs. the general population, and an enrichment in rare variants affecting the catalytic domain (OR 13.9, 1.9-612; p=0.002). In the UK Biobank cohort, loss-of-function ATG7 variants increased the risk of cirrhosis and hepatocellular carcinoma (OR 3.30, 1.1-7.5 and OR 12.30, 2.6-36, respectively; p<0.001 for both). The low-frequency loss-of-function p.V471A variant (rs36117895 T>C) was also associated with severe NAFLD in the clinical cohort (OR=1.7, 1.2-2.5; p=0.003), predisposed to hepatocellular ballooning (p=0.007) evolving to fibrosis in a Liver biopsy cohort (n=2268), and was associated with liver injury in the UK Biobank (AST levels, p<0.001), with a larger effect in severely obese individuals where it was linked to hepatocellular carcinoma (p=0.009). ATG7 protein localized to periportal hepatocytes, more so in the presence of ballooning. In the Liver Transcriptomic cohort (n=125) ATG7 expression correlated with suppression of the TNFα pathway, which was conversely upregulated in p.V471A carriers.We identified rare and low-frequency ATG7 loss-of-function variants as modifiers of NAFLD progression by impairing autophagy and facilitating ballooning and inflammation.•We found that rare mutations in a gene called autophagy related (ATG7) increase the risk of developing severe liver disease in individuals with dysmetabolism. •These mutations cause an alteration in protein function and impairment of self-renewal of cellular content, leading to liver damage and inflammation.
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  • Bianco, Christina, et al. (author)
  • Genetic risk scores and personalization of care in fatty liver disease.
  • 2021
  • In: Current opinion in pharmacology. - : Elsevier BV. - 1471-4973 .- 1471-4892. ; 61, s. 6-11
  • Journal article (peer-reviewed)abstract
    • Nonalcoholic fatty liver diseaseis the leading cause of chronic liver disease. Genetic predisposition, lifestyle, and metabolic comorbidities concur to nonalcoholic fatty liver disease development and progression to nonalcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma. Improvement in risk stratification and development of effective therapies for nonalcoholic steatohepatitis are key unmet clinical needs. Knowledge emerging from genomics could meet this need. A polygenic risk score (PRS) is calculated by summing the number of trait-associated alleles carried by an individual, which can be weighted by their effectsize on the trait and captures the individual's genetic risk to develop a disease. In this review, we focalize on the potential use of PRSs for disease detection at an early stage and stratification of the risk of progression to severe forms. PRSs may represent robust instruments to implement targeted prevention programs, hepatocellular carcinoma surveillance in at-risk individuals, and to develop precision medicine therapeutic approaches.
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15.
  • Bianco, Cristina, et al. (author)
  • Non-invasive stratification of hepatocellular carcinoma risk in non-alcoholic fatty liver using polygenic risk scores.
  • 2021
  • In: Journal of hepatology. - : Elsevier BV. - 1600-0641 .- 0168-8278. ; 74:4, s. 775-782
  • Journal article (peer-reviewed)abstract
    • Hepatocellular carcinoma (HCC) risk stratification in individuals with dysmetabolism is a major unmet need. Genetic predisposition contributes to non-alcoholic fatty liver disease (NAFLD). We aimed to exploit robust polygenic risk scores (PRS) that can be evaluated in the clinic to gain insight into the causal relationship between NAFLD and HCC, and to improve HCC risk stratification.We examined at-risk individuals (NAFLD cohort, n=2,566; 226 with HCC; and a replication cohort of 427 German patients with NAFLD) and the general population (UK Biobank [UKBB] cohort, n=364,048; 202 with HCC). Variants in PNPLA3-TM6SF2-GCKR-MBOAT7 were combined in a hepatic fat PRS (PRS-HFC), and then adjusted for HSD17B13 (PRS-5).In the NAFLD cohort, the adjusted impact of genetic risk variants on HCC was proportional to the predisposition to fatty liver (p=0.002) with some heterogeneity in the effect. PRS predicted HCC more robustly than single variants (p<10-13). The association between PRS and HCC was mainly mediated through severe fibrosis, but was independent of fibrosis in clinically relevant subgroups, and was also observed in those without severe fibrosis (p<0.05). In the UKBB cohort, PRS predicted HCC independently of classical risk factors and cirrhosis (p<10-7). In the NAFLD cohort, we identified high PRS cut-offs (≥0.532/0.495 for PRS-HFC/PRS-5) that in the UKBB cohort detected HCC with ∼90% specificity but limited sensitivity; PRS predicted HCC both in individuals with (p<10-5) and without cirrhosis (p<0.05).Our results are consistent with a causal relationship between hepatic fat and HCC. PRS improved the accuracy to detect HCC and may help stratify HCC risk in individuals with dysmetabolism, including those without severe liver fibrosis. Further studies are needed to validate our findings.
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  • Bianco, Cristiana, et al. (author)
  • Predictors of controlled attenuation parameter in metabolic dysfunction
  • 2024
  • In: United European Gastroenterology Journal. - 2050-6406 .- 2050-6414. ; 12:3, s. 364-373
  • Journal article (peer-reviewed)abstract
    • Background & Aims: Hepatic fat content can be non-invasively estimated by controlled attenuation parameter (CAP) during transient elastography. The aim of this study was to examine the determinants and predictors of CAP values in individuals with metabolic dysfunction. Methods: We enrolled 1230 consecutive apparently healthy individuals (Liver-Bible-2022 cohort) with ≥3 metabolic dysfunction features. CAP was measured by Fibroscan. CAP determinants and predictors were identified using backward stepwise analysis and introduced in generalized linear models. Results: Participants were predominantly males (82.9%), mean age was 53.8±6.4years, 600 (48.8%) had steatosis (CAP≥275dB/m), and 27 had liver stiffness measurement (LSM)≥8kPa. CAP values correlated with LSM (p<10−22). In multivariable analysis, fasting insulin and abdominal circumference (AC) were the main determinants of CAP (p<10−6), together with body mass index (BMI; p<10−4), age, diabetes, triglycerides, ferritin, and lower HDL and thyroid stimulating hormone (TSH; p<0.05 for all). In a subset of 592 participants with thyroid hormone measurement, we found an association between higher free triiodothyronine levels, correlating with lower TSH, and CAP values, independent of TSH and of levothyroxine treatment (p=0.0025). A clinical CAP score based on age, BMI, AC, HbA1c, ALT, and HDL predicted CAP≥275dB/m with moderate accuracy (AUROC=0.73), which was better than that of the Fatty Liver Index and of ALT (AUROC=0.70/0.61, respectively) and validated it in multiple cohorts. Conclusion: Abdominal adiposity and insulin resistance severity were the main determinants of CAP in individuals with metabolic dysfunction and may improve steatotic liver disease risk stratification. CAP values were modulated by the hypophysis-thyroid axis.
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  • Buch, S., et al. (author)
  • Genetic variation in TERT modifies the risk of hepatocellular carcinoma in alcohol-related cirrhosis: results from a genome-wide case-control study
  • 2023
  • In: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 72:2, s. 381-391
  • Journal article (peer-reviewed)abstract
    • Objective Hepatocellular carcinoma (HCC) often develops in patients with alcohol-related cirrhosis at an annual risk of up to 2.5%. Some host genetic risk factors have been identified but do not account for the majority of the variance in occurrence. This study aimed to identify novel susceptibility loci for the development of HCC in people with alcohol related cirrhosis. Design Patients with alcohol-related cirrhosis and HCC (cases: n=1214) and controls without HCC (n=1866), recruited from Germany, Austria, Switzerland, Italy and the UK, were included in a two-stage genome-wide association study using a case-control design. A validation cohort of 1520 people misusing alcohol but with no evidence of liver disease was included to control for possible association effects with alcohol misuse. Genotyping was performed using the InfiniumGlobal Screening Array (V.24v2, Illumina) and the OmniExpress Array (V.24v1-0a, Illumina). Results Associations with variants rs738409 in PNPLA3 and rs58542926 in TM6SF2 previously associated with an increased risk of HCC in patients with alcohol-related cirrhosis were confirmed at genome-wide significance. A novel locus rs2242652(A) in TERT (telomerase reverse transcriptase) was also associated with a decreased risk of HCC, in the combined meta-analysis, at genome-wide significance (p=6.41x10(-9), OR=0.61 (95% CI 0.52 to 0.70). This protective association remained significant after correction for sex, age, body mass index and type 2 diabetes (p=7.94x10(-5), OR=0.63 (95% CI 0.50 to 0.79). Carriage of rs2242652(A) in TERT was associated with an increased leucocyte telomere length (p=2.12x10(-44)). Conclusion This study identifies rs2242652 in TERT as a novel protective factor for HCC in patients with alcohol-related cirrhosis.
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  • Burza, Maria Antonella, 1980, et al. (author)
  • DEPDC5 variants increase fibrosis progression in Europeans with chronic HCV infection.
  • 2016
  • In: Hepatology (Baltimore, Md.). - : Ovid Technologies (Wolters Kluwer Health). - 1527-3350 .- 0270-9139. ; 63:2, s. 418-427
  • Journal article (peer-reviewed)abstract
    • Chronic hepatitis C virus (HCV) infection may progress to cirrhosis and hepatocellular carcinoma (HCC). Recently, two genetic variants, DEPDC5 rs1012068 and MICA rs2596542, were associated with the onset of HCC in Asian subjects with chronic HCV infection. The aim of the present study was to analyze whether DEPDC5 and MICA genetic variants were associated with liver disease progression in Europeans with chronic HCV infection. In a Northern Italian discovery cohort (n=477), neither DEPDC5 rs1012068 nor MICA rs2596542 were associated with HCC (n=150). However, DEPDC5 rs1012068 was independently associated with cirrhosis (n=300; p=0.049). The association of rs1012068 with moderate-severe fibrosis was confirmed in an independent cross-sectional German cohort (n=415; p=0.006). Furthermore, DEPDC5 rs1012068 predicted faster fibrosis progression in a prospective cohort (n=247; p=0.027). Next, we examined the distribution of non-synonymous DEPDC5 variants in the overall cross-sectional cohort (n=912). The presence of at least one variant increased the risk of moderate/severe fibrosis by 54% (p=0.040). To understand the molecular mechanism underlying the genetic association of DEPDC5 variants with fibrosis progression, we performed in vitro studies on immortalized hepatic stellate cells (LX-2). In these cells, down-regulation of DEPDC5 resulted in increased expression of β-catenin and production of its target matrix metallopeptidase 2 (MMP2), a secreted enzyme involved in fibrosis progression.
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19.
  • Cao, Yi, et al. (author)
  • A strong ultraviolet pulse from a newborn type Ia supernova
  • 2015
  • In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 521:7552, s. 328-
  • Journal article (peer-reviewed)abstract
    • Type Ia supernovae(1) are destructive explosions of carbon-oxygen white dwarfs(2,3). Although they are used empirically to measure cosmological distances(4-6), the nature of their progenitors remains mysterious(3). One of the leading progenitor models, called the single degenerate channel, hypothesizes that a white dwarf accretes matter from a companion star and the resulting increase in its central pressure and temperature ignites thermonuclear explosion(3,7,8). Here we report observations with the Swift Space Telescope of strong but declining ultraviolet emission from a type Ia supernova within four days of its explosion. This emission is consistent with theoretical expectations of collision between material ejected by the supernova and a companion star(9), and therefore provides evidence that some type Ia supernovae arise from the single degenerate channel.
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21.
  • Cherubini, Alessandro, et al. (author)
  • Interaction between estrogen receptor-α and PNPLA3 p.I148M variant drives fatty liver disease susceptibility in women.
  • 2023
  • In: Nature medicine. - 1546-170X. ; 29:10, s. 2643-55
  • Journal article (peer-reviewed)abstract
    • Fatty liver disease (FLD) caused by metabolic dysfunction is the leading cause of liver disease and the prevalence is rising, especially in women. Although during reproductive age women are protected against FLD, for still unknown and understudied reasons some develop rapidly progressive disease at the menopause. The patatin-like phospholipase domain-containing 3 (PNPLA3) p.I148M variant accounts for the largest fraction of inherited FLD variability. In the present study, we show that there is a specific multiplicative interaction between female sex and PNPLA3 p.I148M in determining FLD in at-risk individuals (steatosis and fibrosis, P<10-10; advanced fibrosis/hepatocellular carcinoma, P=0.034) and in the general population (P<10-7 for alanine transaminase levels). In individuals with obesity, hepatic PNPLA3 expression was higher in women than in men (P=0.007) and in mice correlated with estrogen levels. In human hepatocytes and liver organoids, PNPLA3 was induced by estrogen receptor-α (ER-α) agonists. By chromatin immunoprecipitation and luciferase assays, we identified and characterized an ER-α-binding site within a PNPLA3 enhancer and demonstrated via CRISPR-Cas9 genome editing that this sequence drives PNPLA3 p.I148M upregulation, leading to lipid droplet accumulation and fibrogenesis in three-dimensional multilineage spheroids with stellate cells. These data suggest that a functional interaction between ER-α and PNPLA3 p.I148M variant contributes to FLD in women.
  •  
22.
  • Cruz, Raquel, et al. (author)
  • Novel genes and sex differences in COVID-19 severity
  • 2022
  • In: Human Molecular Genetics. - : Oxford University Press. - 0964-6906 .- 1460-2083. ; 31:22, s. 3789-3806
  • Journal article (peer-reviewed)abstract
    • Here, we describe the results of a genome-wide study conducted in 11 939 coronavirus disease 2019 (COVID-19) positive cases with an extensive clinical information that were recruited from 34 hospitals across Spain (SCOURGE consortium). In sex-disaggregated genome-wide association studies for COVID-19 hospitalization, genome-wide significance (P < 5 × 10−8) was crossed for variants in 3p21.31 and 21q22.11 loci only among males (P = 1.3 × 10−22 and P = 8.1 × 10−12, respectively), and for variants in 9q21.32 near TLE1 only among females (P = 4.4 × 10−8). In a second phase, results were combined with an independent Spanish cohort (1598 COVID-19 cases and 1068 population controls), revealing in the overall analysis two novel risk loci in 9p13.3 and 19q13.12, with fine-mapping prioritized variants functionally associated with AQP3 (P = 2.7 × 10−8) and ARHGAP33 (P = 1.3 × 10−8), respectively. The meta-analysis of both phases with four European studies stratified by sex from the Host Genetics Initiative (HGI) confirmed the association of the 3p21.31 and 21q22.11 loci predominantly in males and replicated a recently reported variant in 11p13 (ELF5, P = 4.1 × 10−8). Six of the COVID-19 HGI discovered loci were replicated and an HGI-based genetic risk score predicted the severity strata in SCOURGE. We also found more SNP-heritability and larger heritability differences by age (<60 or ≥60 years) among males than among females. Parallel genome-wide screening of inbreeding depression in SCOURGE also showed an effect of homozygosity in COVID-19 hospitalization and severity and this effect was stronger among older males. In summary, new candidate genes for COVID-19 severity and evidence supporting genetic disparities among sexes are provided.
  •  
23.
  • De Vincentis, Antonio, et al. (author)
  • A Polygenic Risk Score to Refine Risk Stratification and Prediction for Severe Liver Disease by Clinical Fibrosis Scores.
  • 2022
  • In: Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association. - : Elsevier BV. - 1542-7714. ; 20:3, s. 658-673
  • Journal article (peer-reviewed)abstract
    • A polygenic risk score based on well-known genetic variants in PNPLA3, TM6SF2, MBOAT7 and GCKR predicts hepatic fat content (PRS-HFC). Here we hypothesize that the addition of PRS-HFC to clinical fibrosis scores may improve risk stratification and prediction of severe liver disease (SLD).We used data from 266,687 individuals in the UK Biobank, evaluating the incidence of cirrhosis, decompensated liver disease, hepatocellular carcinoma and/or liver transplantation during a median follow-up of 9 years. NAFLD fibrosis score (NFS), FIB-4, APRI, BARD and Forns scores, and PRS-HFC, were computed. All analyses were stratified according to the presence of diabetes, obesity and positive fatty liver index (FLI≥60).Unfavorable genetics (PRS-HFC≥0.396) further stratified the risk of SLD in subjects in intermediate/high risk classes of fibrosis scores, with higher effect in those with metabolic risk factors, and the prediction was improved by integrating PRS-HFC (AUROCs increased for all scores with p∼10-2-10-4, except for APRI in the overall population and in subjects with obesity. PRS-HFC improved diagnostic accuracies and positive predictive values for SLD in intermediate-high clinical score risk classes. Risk stratification and prediction were not/poorly affected by unfavorable genetics in subjects without metabolic risk factors.Integration of genetics with clinical fibrosis scores refines individual risk and prediction for SLD, mainly in individuals at risk for NAFLD. These data provide first evidence from a prospective cohort that common genetic variants capture additional prognostic insights not conveyed by validated clinical/biochemical parameters.
  •  
24.
  • De Vincentis, Antonio, et al. (author)
  • Genetic variants in the MTHFR are not associated with fatty liver disease.
  • 2020
  • In: Liver international : official journal of the International Association for the Study of the Liver. - : Wiley. - 1478-3231. ; 40:8, s. 1934-1940
  • Journal article (peer-reviewed)abstract
    • The common missense sequence variants of methylenetetrahydrofolate-reductase (MTHFR), rs1801131 (c.A1298C) and rs1801133 (c.C677T), favor the development of hyperhomocysteinemia and diminished DNA methylation. Previous studies, carried out in small series and with suboptimal characterization of the hepatic phenotype, tested the association of these genetic variants with fatty liver disease (FLD), with conflicting results. Here, we assessed the association of rs1801131 and rs1801133 with hepatic phenotype in the Liver Biopsy Cross-Sectional Cohort, a large cohort (n=1375 from Italy and 411 from Finland) of European individuals with suspect FLD associated with dysmetabolism. A total of 1786 subjects were analyzed by ordinal regression analyses. The rs1801131 and the rs1801133 variants were not associated with steatosis, inflammation, ballooning, or fibrosis. The present study suggests that changes in folate and methionine metabolism resulting from these 2 variants are not associated with a clinically significant impact on FLD in Europeans.
  •  
25.
  • De Vincentis, A., et al. (author)
  • Metabolic and genetic determinants for progression to severe liver disease in subjects with obesity from the UK Biobank
  • 2022
  • In: International Journal of Obesity. - : Springer Science and Business Media LLC. - 0307-0565 .- 1476-5497. ; 46, s. 486-493
  • Journal article (peer-reviewed)abstract
    • Background Obesity is among the main determinants of nonalcoholic fatty liver disease progression towards severe liver disease (SLD). However, risk factors for SLD in individuals with obesity have not been examined. Objectives To identify the independent risk factors for SLD among participants with obesity from the UK Biobank. Methods A total of 80,224 UK Biobank participants with obesity (body mass index[BMI] > 30 kg/m(2)) and 242,822 without obesity, of European descent without clinical history of liver disease and liver cancer were prospectively followed for the onset of SLD, defined as a composite diagnosis of cirrhosis, decompensated liver disease, hepatocellular carcinoma and/or liver transplantation. Risk factors for incident SLD were assessed by Cox proportional hazards models. Different clinical phenotypes were derived by latent class analysis (LCA). Results Obesity conferred a 2.6-fold increased risk for SLD that was abolished after the inclusion of waist circumference (WC) in the model. Among individuals with obesity, age (adjusted hazard ratio [aHR] 1.05, 95%CI 1.03-1.07, p = 3.9 * 10(-7)), type 2 diabetes (aHR 2.18, 95%CI 1.55-3.05, p = 6.2 * 10(-6)), PNPLA3 rs738409 (aHR 1.59, 95%CI 1.33-1.9, p = 3.1 * 10(-7)) and WC (aHR 1.04, 95%CI 1.02-1.06, p = 8.5 * 10(-6)) were independent predictors of SLD. BMI category-specific WC thresholds allowed a better risk stratification compared to traditional ones. By LCA, the clinical phenotype at highest risk for SLD was that with BMI < 35 kg/m(2) and WC above BMI-category specific thresholds. Conclusions Age, WC, type 2 diabetes, and the PNPLA3 variant are the main risk factors for SLD in individuals with obesity. WC is the principal mediator of SLD risk conveyed by increased BMI. BMI category-specific WC-thresholds may refine the SLD risk more accurately than traditional thresholds.
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26.
  • De Vincentis, Antonio, et al. (author)
  • Poor accuracy and sustainability of the first-step FIB4 EASL pathway for stratifying steatotic liver disease risk in the general population.
  • 2024
  • In: Alimentary Pharmacology and Therapeutics. - 0269-2813. ; 59:11, s. 1402-1412
  • Journal article (peer-reviewed)abstract
    • The European Association for the Study of the Liver introduced a clinical pathway (EASL CP) for screening significant/advanced fibrosis in people at risk of steatotic liver disease (SLD). We assessed the performance of the first-step FIB4 EASL CP in the general population across different SLD risk groups (MASLD, Met-ALD and ALD) and various age classes.We analysed a total of 3372 individuals at risk of SLD from the 2017-2018 National Health and Nutrition Examination Survey (NHANES17-18), projected to 152.3million U.S. adults, 300,329 from the UK Biobank (UKBB) and 57,644 from the Biobank Japan (BBJ). We assessed liver stiffness measurement (LSM) ≥8kPa and liver-related events occurring within 3 and 10years (3/10year-LREs) as outcomes. We defined MASLD, MetALD, and ALD according to recent international recommendations.FIB4 sensitivity for LSM≥8kPa was low (27.7%), but it ranged approximately 80%-90% for 3-year LREs. Using FIB4, 22%-57% of subjects across the three cohorts were identified as candidates for vibration-controlled transient elastography (VCTE), which was mostly avoidable (positive predictive value of FIB4≥1.3 for LSM≥8kPa ranging 9.5%-13% across different SLD categories). Sensitivity for LSM≥8kPa and LREs increased with increasing alcohol intake (ALD>MetALD>MASLD) and age classes. For individuals aged ≥65years, using the recommended age-adjusted FIB4 cut-off (≥2) substantially reduced sensitivity for LSM≥8kPa and LREs.The first-step FIB4 EASL CP is poorly accurate and feasible for individuals at risk of SLD in the general population. It is crucial to enhance the screening strategy with a first-step approach able to reduce unnecessary VCTEs and optimise their yield.
  •  
27.
  • Donati, B., et al. (author)
  • MBOAT7 rs641738 variant and hepatocellular carcinoma in non-cirrhotic individuals
  • 2017
  • In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7:1
  • Journal article (peer-reviewed)abstract
    • Nonalcoholic fatty liver disease (NAFLD) represents an emerging cause of hepatocellular carcinoma (HCC), especially in non-cirrhotic individuals. The rs641738 C > T MBOAT7/TMC4 variant predisposes to progressive NAFLD, but the impact on hepatic carcinogenesis is unknown. In Italian NAFLD patients, the rs641738 T allele was associated with NAFLD-HCC (OR 1.65, 1.08-2.55; n = 765), particularly in those without advanced fibrosis (p < 0.001). The risk T allele was linked to 3'-UTR variation in MBOAT7 and to reduced MBOAT7 expression in patients without severe fibrosis. The number of PNPLA3, TM6SF2, and MBOAT7 risk variants was associated with NAFLD-HCC independently of clinical factors (p < 0.001), but did not significantly improve their predictive accuracy. When combining data from an independent UK NAFLD cohort, in the overall cohort of non-cirrhotic patients (n = 913, 41 with HCC) the T allele remained associated with HCC (OR 2.10, 1.33-3.31). Finally, in a combined cohort of non-cirrhotic patients with chronic hepatitis C or alcoholic liver disease (n = 1121), the T allele was independently associated with HCC risk (OR 1.93, 1.07-3.58). In conclusion, the MBOAT7 rs641738 T allele is associated with reduced MBOAT7 expression and may predispose to HCC in patients without cirrhosis, suggesting it should be evaluated in future prospective studies aimed at stratifying NAFLD-HCC risk.
  •  
28.
  • Donati, Benedetta, et al. (author)
  • Telomerase reverse transcriptase germline mutations and hepatocellular carcinoma in patients with nonalcoholic fatty liver disease.
  • 2017
  • In: Cancer medicine. - : Wiley. - 2045-7634. ; 6:8, s. 1930-1940
  • Journal article (peer-reviewed)abstract
    • In an increasing proportion of cases, hepatocellular carcinoma (HCC) develops in patients with nonalcoholic fatty liver disease (NAFLD). Mutations in telomerase reverse transcriptase (hTERT) are associated with familial liver diseases. The aim of this study was to examine telomere length and germline hTERT mutations as associated with NAFLD-HCC. In 40 patients with NAFLD-HCC, 45 with NAFLD-cirrhosis and 64 healthy controls, peripheral blood telomere length was evaluated by qRT-PCR and hTERT coding regions and intron-exon boundaries sequenced. We further analyzed 78 patients affected by primary liver cancer (NAFLD-PLC, 76 with HCC). Enrichment of rare coding mutations (allelic frequency <0.001) was evaluated by Burden test. Functional consequences were estimated in silico and by over-expressing protein variants in HEK-293 cells. We found that telomere length was reduced in individuals with NAFLD-HCC versus those with cirrhosis (P=0.048) and healthy controls (P=0.0006), independently of age and sex. We detected an enrichment of hTERT mutations in NAFLD-HCC, that was confirmed when we further considered a larger cohort of NAFLD-PLC, and was more marked in female patients (P=0.03). No mutations were found in cirrhosis and local controls, and only one in 503 healthy Europeans from the 1000 Genomes Project (allelic frequency=0.025 vs. <0.001; P=0.0005). Mutations with predicted functional impact, including the frameshift Glu113Argfs*79 and missense Glu668Asp, cosegregated with liver disease in two families. Three patients carried missense mutations (Ala67Val in homozygosity, Pro193Leu and His296Pro in heterozygosity) in the N-terminal template-binding domain (P=0.037 for specific enrichment). Besides Glu668Asp, the Ala67Val variant resulted in reduced intracellular protein levels. In conclusion, we detected an association between shorter telomeres in peripheral blood and rare germline hTERT mutations and NAFLD-HCC.
  •  
29.
  • Donati, Benedetta, et al. (author)
  • The rs2294918 E434K variant modulates PNPLA3 expression and liver damage.
  • 2016
  • In: Hepatology (Baltimore, Md.). - : Ovid Technologies (Wolters Kluwer Health). - 1527-3350 .- 0270-9139. ; 63:3, s. 787-798
  • Journal article (peer-reviewed)abstract
    • The PNPLA3 rs738409 polymorphism (I148M) is a major determinant of hepatic fat and predisposes to the full spectrum of liver damage in nonalcoholic fatty liver disease (NAFLD). Aim of this study was to evaluate whether additional PNPLA3 coding variants contribute to NAFLD susceptibility, first in individuals with contrasting phenotypes (with early onset NAFLD vs. very low aminotransferases), and then in a large validation cohort. Rare PNPLA3 variants were not detected by sequencing coding regions and intron-exon boundaries either in 142 patients with early-onset NAFLD, nor in 100 healthy individuals with ALT <22/20 IU/ml. Besides rs738409 I148M, the rs2294918 G>A polymorphism (E434K sequence variant) was over-represented in NAFLD (adjusted p=0.01). In 1447 subjects with and without NAFLD, the 148M-434E (p<0.0001), but not the 148M-434K haplotype (p>0.9), was associated with histological NAFLD and steatohepatitis. Both the I148M (p=0.0002) and E434K variants (p=0.044) were associated with serum ALT levels, by interacting each other, in that the 434K hampered the association with liver damage of the 148M allele (p=0.006). The E434K variant did not affect PNPLA3 enzymatic activity, but carriers of the rs2294918 A allele (434K) displayed lower hepatic PNPLA3 mRNA and protein levels (p<0.05).
  •  
30.
  • Dongiovanni, P, et al. (author)
  • Causal relationship of hepatic fat with liver damage and insulin resistance in nonalcoholic fatty liver.
  • 2018
  • In: Journal of internal medicine. - : Wiley. - 1365-2796 .- 1365-2796 .- 0954-6820. ; 283:4, s. 356-370
  • Journal article (peer-reviewed)abstract
    • Nonalcoholic fatty liver disease is epidemiologically associated with hepatic and metabolic disorders. The aim of this study was to examine whether hepatic fat accumulation has a causal role in determining liver damage and insulin resistance.We performed a Mendelian randomization analysis using risk alleles in PNPLA3, TM6SF2, GCKR and MBOAT7, and a polygenic risk score for hepatic fat, as instruments. We evaluated complementary cohorts of at-risk individuals and individuals from the general population: 1515 from the liver biopsy cohort (LBC), 3329 from the Swedish Obese Subjects Study (SOS) and 4570 from the population-based Dallas Heart Study (DHS).Hepatic fat was epidemiologically associated with liver damage, insulin resistance, dyslipidemia and hypertension. The impact of genetic variants on liver damage was proportional to their effect on hepatic fat accumulation. Genetically determined hepatic fat was associated with aminotransferases, and with inflammation, ballooning and fibrosis in the LBC. Furthermore, in the LBC, the causal association between hepatic fat and fibrosis was independent of disease activity, suggesting that a causal effect of long-term liver fat accumulation on liver disease is independent of inflammation. Genetically determined hepatic steatosis was associated with insulin resistance in the LBC and SOS. However, this association was dependent on liver damage severity. Genetically determined hepatic steatosis was associated with liver fibrosis/cirrhosis and with a small increase in risk of type 2 diabetes in publicly available databases.These data suggest that long-term hepatic fat accumulation plays a causal role in the development of chronic liver disease.
  •  
31.
  • Dongiovanni, P., et al. (author)
  • Genetic Factors in the Pathogenesis of Nonalcoholic Fatty Liver and Steatohepatitis
  • 2015
  • In: Biomed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141.
  • Journal article (peer-reviewed)abstract
    • Liver fat accumulation generally related to systemic insulin resistance characterizes nonalcoholic fatty liver disease (NAFLD), which in the presence of nonalcoholic steatohepatitis (NASH) can progress towards cirrhosis and hepatocellular carcinoma. Due to the epidemic of obesity, NAFLD is now the most frequent liver disease in Western countries. Epidemiological, familial, and twin studies provide evidence for a strong genetic component of NAFLD susceptibility. Recently, genome-wide association studies led to the identification of the major inherited determinants of hepatic fat accumulation: patatin-like phospholipase domain-containing 3 (PNPLA3) I148M gene and transmembrane 6 superfamily member 2 (TM6SF2) E167K gene variants, involved in lipid droplets remodelling and very low-density lipoproteins secretion, are the major determinants of interindividual differences in liver steatosis, and susceptibility to progressive NASH. In this review, we aimed to provide an overview of recent insights into the genetics of hepatic fat accumulation and steatohepatitis.
  •  
32.
  • Dongiovanni, P., et al. (author)
  • Hepatocellular carcinoma in nonalcoholic fatty liver: Role of environmental and genetic factors
  • 2014
  • In: World Journal of Gastroenterology. - : Baishideng Publishing Group Inc.. - 1007-9327. ; 20:36, s. 12945-12955
  • Journal article (peer-reviewed)abstract
    • Hepatocellular carcinoma (HCC) is the fourth cause of cancer related mortality, and its incidence is rapidly increasing. Viral hepatitis, alcohol abuse, and exposure to hepatotoxins are major risk factors, but nonalcoholic fatty liver disease (NAFLD) associated with obesity, insulin resistance, and type 2 diabetes, is an increasingly recognized trigger, especially in developed countries. Older age, severity of insulin resistance and diabetes, and iron overload have been reported to predispose to HCC in this context. Remarkably, HCCs have been reported in non-cirrhotic livers in a higher proportion of cases in NAFLD patients than in other etiologies. Inherited factors have also been implicated to explain the different individual susceptibility to develop HCC, and their role seems magnified in fatty liver, where only a minority of affected subjects progresses to cancer. In particular, the common I148M variant of the PNPLA3 gene influencing hepatic lipid metabolism influences HCC risk independently of its effect on the progression of liver fibrosis. Recently, rare loss-of-function mutations in Apolipoprotein B resulting in very low density lipoproteins hepatic retention and in Telomerase reverse transcriptase influencing cellular senescence have also been linked to HCC in NAFLD. Indeed, hepatic stellate cells senescence has been suggested to bridge tissue aging with alterations of the intestinal microbiota in the pathogenesis of obesity-related HCC. A deeper understanding of the mechanisms mediating hepatic carcinogenesis during insulin resistance, and the identification of its genetic determinants will hopefully provide new diagnostic and therapeutic tools.
  •  
33.
  • Dongiovanni, Paola, et al. (author)
  • PCSK7 gene variation bridges atherogenic dyslipidemia with hepatic inflammation in NAFLD patients.
  • 2019
  • In: Journal of lipid research. - 1539-7262. ; 60:June, s. 1144-1153
  • Journal article (peer-reviewed)abstract
    • Dyslipidemia and altered iron metabolism are typical features of non-alcoholic fatty liver disease (NAFLD). Proprotein Convertase Subtilisin/Kexin Type 7 (PCSK7) gene variation has been associated with circulating lipids and liver damage during iron overload. Aim of this study was to examine the impact of the PCSK7 rs236918 variant on NAFLD-related traits in 1,801 individuals from the Liver Biopsy Cohort (LBC), 500,000 from the UK Biobank Cohort (UKBBC), and 4,580 from the Dallas Heart Study (DHS). The minor PCSK7 rs236918 C allele was associated with higher triglycerides, aminotransferases and hepatic inflammation in the LBC (p<0.05) and with hypercholesterolemia and liver disease in the UKBBC. In the DHS, PCSK7 missense variants were associated with circulating lipids. PCSK7 was expressed in hepatocytes and its hepatic expression correlated with that of lipogenic genes (p<0.05). The rs236918 C allele was associated with upregulation of a new 'intra-PCSK7' lnc-RNA predicted to interact with the protein, higher hepatic and circulating PCSK7 protein (p<0.01), and the latter correlated with triglycerides (p=0.04). In HepG2, PCSK7 deletion reduced lipogenesis, fat accumulation, inflammation, TGFB pathway activation and fibrogenesis. In conclusion, PCSK7 gene variation is associated with dyslipidemia and more severe liver disease in high risk individuals, likely by modulating PCSK7 expression/activity.
  •  
34.
  • Dongiovanni, P., et al. (author)
  • PNPLA3 I148M polymorphism and progressive liver disease
  • 2013
  • In: World Journal of Gastroenterology. - : Baishideng Publishing Group Inc.. - 1007-9327. ; 19:41, s. 6969-6978
  • Journal article (peer-reviewed)abstract
    • The 148 Isoleucine to Methionine protein variant (I148M) of patatin-like phospholipase domain-containing 3 (PNPLA3), a protein is expressed in the liver and is involved in lipid metabolism, has recently been identified as a major determinant of liver fat content. Several studies confirmed that the I148M variant predisposes towards the full spectrum of liver damage associated with fatty liver: from simple steatosis to steatohepatitis and progressive fibrosis. Furthermore, the I148M variant represents a major determinant of progression of alcohol related steatohepatitis to cirrhosis, and to influence fibrogenesis and related clinical outcomes in chronic hepatitis C virus hepatitis, and possibly chronic hepatitis B virus hepatitis, hereditary hemochromatosis and primary sclerosing cholangitis. All in all, studies suggest that the I148M polymorphism may represent a general modifier of fibrogenesis in liver diseases. Remarkably, the effect of the I148M variant on fibrosis was independent of that on hepatic steatosis and inflammation, suggesting that it may affect both the quantity and quality of hepatic lipids and the biology of non-parenchymal liver cells besides hepatocytes, directly promoting fibrogenesis. Therefore, PNPLA3 is a key player in liver disease progression. Assessment of the I148M polymorphism will possibly inform clinical practice in the future, whereas the determination of the effect of the 148M variant will reveal mechanisms involved in hepatic fibrogenesis. (C) 2013 Baishideng Publishing Group Co., Limited. All rights reserved.
  •  
35.
  • Dongiovanni, Paola, et al. (author)
  • Protein phosphatase 1 regulatory subunit 3B gene variation protects against hepatic fat accumulation and fibrosis in individuals at high risk of nonalcoholic fatty liver disease.
  • 2018
  • In: Hepatology communications. - : Ovid Technologies (Wolters Kluwer Health). - 2471-254X. ; 2:6, s. 666-675
  • Journal article (peer-reviewed)abstract
    • Nonalcoholic fatty liver disease (NAFLD) is a major cause of liver damage and has a strong genetic component. The rs4841132 G>A variant, modulating the expression of protein phosphatase 1 regulatory subunit 3B (PPP1R3B), which is involved in glycogen synthesis, has been reported to reduce the risk of NAFLD but at the same time may favor liver disease by facilitating glycogen accumulation. The aim of this study was to assess the impact of rs4841132 on development of histologic steatosis and fibrosis in 1,388 European individuals in a liver biopsy cohort, on NAFLD hepatocellular carcinoma in a cross-sectional Italian cohort (n = 132 cases), and on liver disease at the population level in the United Kingdom Biobank cohort. We investigated the underlying mechanism by examining the impact of the variant on gene expression profiles. In the liver biopsy cohort, the rs4841132 minor A allele was associated with protection against steatosis (odds ratio [OR], 0.63; 95% confidence interval [CI], 0.42-0.95; P = 0.03) and clinically significant fibrosis (OR, 0.35; 95% CI, 0.14-0.87; P = 0.02) and with reduced circulating cholesterol (P = 0.02). This translated into protection against hepatocellular carcinoma development (OR, 0.22; 95% CI, 0.07-0.70; P = 0.01). At the population level, the rs4841132 variation was not associated with nonalcoholic or nonviral diseases of the liver but was associated with lower cholesterol (P = 1.7 × 10-8). In individuals with obesity, the A allele protecting against steatosis was associated with increased PPP1R3B messenger RNA expression and activation of lipid oxidation and with down-regulation of pathways related to lipid metabolism, inflammation, and cell cycle. Conclusion: The rs4841132 A allele is associated with protection against hepatic steatosis and fibrosis in individuals at high risk of NAFLD but not in the general population and against dyslipidemia. The mechanism may be related to modulation of PPP1R3B expression and hepatic lipid metabolism. (Hepatology Communications 2018;2:666-675).
  •  
36.
  • Dongiovanni, Paola, et al. (author)
  • Statin use and nonalcoholic steatohepatitis in at risk individuals.
  • 2015
  • In: Journal of hepatology. - : Elsevier BV. - 1600-0641 .- 0168-8278. ; 63:3, s. 705-712
  • Journal article (peer-reviewed)abstract
    • Excess hepatic free cholesterol contributes to the pathogenesis of nonalcoholic steatohepatitis, and statins reduce cholesterol synthesis. Aim of this study was to assess whether statin use is associated with histological liver damage related to steatohepatitis.
  •  
37.
  • Dongiovanni, P., et al. (author)
  • Transmembrane 6 Superfamily Member 2 Gene Variant Disentangles Nonalcoholic Steatohepatitis From Cardiovascular Disease
  • 2015
  • In: Hepatology. - : Ovid Technologies (Wolters Kluwer Health). - 0270-9139 .- 1527-3350. ; 61:2, s. 506-514
  • Journal article (peer-reviewed)abstract
    • Excess hepatic storage of triglycerides is considered a benign condition, but nonalcoholic steatohepatitis (NASH) may progress to fibrosis and promote atherosclerosis. Carriers of the TM6SF2 E167K variant have fatty liver as a result of reduced secretion of very-low-density lipoproteins (VLDLs). As a result, they have lower circulating lipids and reduced risk of myocardial infarction. In this study, we aimed to assess whether TM6SF2 E167K affects liver damage and cardiovascular outcomes in subjects at risk of NASH. Liver damage was evaluated in 1,201 patients who underwent liver biopsy for suspected NASH; 427 were evaluated for carotid atherosclerosis. Cardiovascular outcomes were assessed in 1,819 controls from the Swedish Obese Subjects (SOS) cohort. Presence of the inherited TM6SF2 E167K variant was determined by TaqMan assays. In the liver biopsy cohort, 188 subjects (13%) were carriers of the E167K variant. They had lower serum lipid levels than noncarriers (P<0.05), had more-severe steatosis, necroinflammation, ballooning, and fibrosis (P<0.05), and were more likely to have NASH (odds ratio [OR]: 1.84; 95% confidence interval [CI]: 1.23-2.79) and advanced fibrosis (OR, 2.08; 95% CI: 1.20-3.55), after adjustment for age, sex, body mass index, fasting hyperglycemia, and the I148M PNPLA3 risk variant. However, E167K carriers had lower risk of developing carotid plaques (OR, 0.49; 95% CI: 0.25-0.94). In the SOS cohort, E167K carriers had higher alanine aminotransferase ALT and lower lipid levels (P<0.05), as well as a lower incidence of cardiovascular events (hazard ratio: 0.61; 95% CI: 0.39-0.95). Conclusions: Carriers of the TM6SF2 E167K variant are more susceptible to progressive NASH, but are protected against cardiovascular disease. Our findings suggest that reduced ability to export VLDLs is deleterious for the liver. (Hepatology 2015;61:506-514)
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38.
  • Grimaudo, Stefania, et al. (author)
  • NR1H4 rs35724 G>C variant modulates liver damage in nonalcoholic fatty liver disease.
  • 2021
  • In: Liver international. - : Wiley. - 1478-3231 .- 1478-3223. ; 41:11, s. 2712-2719
  • Journal article (peer-reviewed)abstract
    • Farnesoid X receptor (FXR) plays a key role in bile acid and lipid homeostasis. Experimental evidence suggests that it can modulate liver damage related to nonalcoholic fatty liver disease (NAFLD). We examined the impact of the NR1H4 rs35724 G>C, encoding for FXR, on liver damage in a large cohort of patients at risk of steatohepatitis.We considered 2,660 consecutive individuals at risk of steatohepatitis with liver histology. The rs35724 G>C polymorphisms were genotyped by TaqMan assays. Gene expression was evaluated by RNASeq in a subset of patients (n=124).The NR1H4 rs35724 CC genotype, after adjusting for clinic-metabolic and genetic confounders and for enrolling centre, was protective against severity of steatosis (GG vs CC OR 0.77, 95% CI 0.62-0.95; P=.01), steatohepatitis (GG vs CC OR 0.62, 95% CI 0.47-0.83; P=.001) and severity of fibrosis (GG vs CC OR 0.83, 95% CI 0.67-0.98; P=.04). The C allele was associated with higher total circulating cholesterol (P=.01). Patients carrying the NR1H4 rs35724 C allele had significantly higher hepatic mRNA levels of FXR and were associated with higher hepatic FGFR4 and Cyp39A1 that are in turn involved in bile acid synthesis.Increased hepatic FXR expression due to the NR1H4 rs35724 C allele is linked to higher serum cholesterol but protects against steatosis, steatohepatitis and liver fibrosis. The translational relevance of these results for patient risk stratification and FXR-targeted therapy warrants further investigation.
  •  
39.
  • Hosseinzadeh, Griffin, et al. (author)
  • Constraining the Progenitor System of the Type Ia Supernova 2021aefx
  • 2022
  • In: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8205 .- 2041-8213. ; 933:2
  • Journal article (peer-reviewed)abstract
    • We present high-cadence optical and ultraviolet light curves of the normal Type Ia supernova (SN) 2021aefx, which shows an early bump during the first two days of observation. This bump may be a signature of interaction between the exploding white dwarf and a nondegenerate binary companion, or it may be intrinsic to the white dwarf explosion mechanism. In the case of the former, the short duration of the bump implies a relatively compact main-sequence companion star, although this conclusion is viewing-angle dependent. Our best-fit companion-shocking and double-detonation models both overpredict the UV luminosity during the bump, and existing nickel-shell models do not match the strength and timescale of the bump. We also present nebular spectra of SN 2021aefx, which do not show the hydrogen or helium emission expected from a nondegenerate companion, as well as a radio nondetection that rules out all symbiotic progenitor systems and most accretion disk winds. Our analysis places strong but conflicting constraints on the progenitor of SN 2021aefx; no current model can explain all of our observations.
  •  
40.
  • Hosseinzadeh, Griffin, et al. (author)
  • Short-lived Circumstellar Interaction in the Low-luminosity Type IIP SN 2016bkv
  • 2018
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 861:1
  • Journal article (peer-reviewed)abstract
    • While interaction with circumstellar material is known to play an important role in Type. IIn supernovae (SNe), analyses of the more common SNe IIP and IIL have not traditionally included interaction as a significant power source. However, recent campaigns to observe SNe within days of explosion have revealed narrow emission lines of high-ionization species in the earliest spectra of luminous SNe II of all subclasses. These flash ionization features indicate the presence of a confined shell of material around the progenitor star. Here we present the first low-luminosity (LL) SN to show flash ionization features, SN 2016bkv. This SN peaked at M-V = -16 mag and has Ha expansion velocities under 1350 km s(-1) around maximum light, placing it at the faint/slow end of the distribution of SNe IIP (similar to SN 2005cs). The light-curve shape of SN 2016bkv is also extreme among SNe IIP. A very strong initial peak could indicate additional luminosity from circumstellar interaction. A very small fall from the plateau to the nickel tail indicates unusually large production of radioactive nickel compared to other LL SNe IIP. A comparison between nebular spectra of SN. 2016bkv and models raises the possibility that SN. 2016bkv is an electron-capture supernova.
  •  
41.
  • Hosseinzadeh, Griffin, et al. (author)
  • The Early Light Curve of SN 2023bee : Constraining Type Ia Supernova Progenitors the Apian Way
  • 2023
  • In: Astrophysical Journal Letters. - 2041-8205 .- 2041-8213. ; 953:1
  • Journal article (peer-reviewed)abstract
    • We present very early photometric and spectroscopic observations of the Type Ia supernova (SN Ia) 2023bee, starting about 8 hr after the explosion, which reveal a strong excess in the optical and nearest UV (U and UVW1) bands during the first several days of explosion. This data set allows us to probe the nature of the binary companion of the exploding white dwarf and the conditions leading to its ignition. We find a good match to the Kasen model in which a main-sequence companion star stings the ejecta with a shock as they buzz past. Models of double detonations, shells of radioactive nickel near the surface, interaction with circumstellar material, and pulsational delayed detonations do not provide good matches to our light curves. We also observe signatures of unburned material, in the form of carbon absorption, in our earliest spectra. Our radio nondetections place a limit on the mass-loss rate from the putative companion that rules out a red giant but allows a main-sequence star. We discuss our results in the context of other similar SNe Ia in the literature.
  •  
42.
  • Jencson, Jacob E., et al. (author)
  • AT 2019qyl in NGC 300 : Internal Collisions in the Early Outflow from a Very Fast Nova in a Symbiotic Binary
  • 2021
  • In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 920:2
  • Journal article (peer-reviewed)abstract
    • Nova eruptions, thermonuclear explosions on the surfaces of white dwarfs (WDs), are now recognized to be among the most common shock-powered astrophysical transients. We present the early discovery and rapid ultraviolet (UV), optical, and infrared (IR) temporal development of AT 2019qyl, a recent nova in the nearby Sculptor Group galaxy NGC 300. The light curve shows a rapid rise lasting ≲1 day, reaching a peak absolute magnitude of MV = −9.2 mag and a very fast decline, fading by 2 mag over 3.5 days. A steep dropoff in the light curves after 71 days and the rapid decline timescale suggest a low-mass ejection from a massive WD with MWD ≳ 1.2 M⊙. We present an unprecedented view of the early spectroscopic evolution of such an event. Three spectra prior to the peak reveal a complex, multicomponent outflow giving rise to internal collisions and shocks in the ejecta of an He/N-class nova. We identify a coincident IR-variable counterpart in the extensive preeruption coverage of the transient location and infer the presence of a symbiotic progenitor system with an O-rich asymptotic-giant-branch donor star, as well as evidence for an earlier UV-bright outburst in 2014. We suggest that AT 2019qyl is analogous to the subset of Galactic recurrent novae with red-giant companions such as RS Oph and other embedded nova systems like V407 Cyg. Our observations provide new evidence that internal shocks between multiple, distinct outflow components likely contribute to the generation of the shock-powered emission from such systems.
  •  
43.
  • Lindén, Daniel, 1971, et al. (author)
  • Pnpla3 silencing with antisense oligonucleotides ameliorates nonalcoholic steatohepatitis and fibrosis in Pnpla3 I148M knock-in mice.
  • 2019
  • In: Molecular metabolism. - : Elsevier BV. - 2212-8778. ; 22:April, s. 49-61
  • Journal article (peer-reviewed)abstract
    • Nonalcoholic fatty liver disease (NAFLD) is becoming a leading cause of advanced chronic liver disease. The progression of NAFLD, including nonalcoholic steatohepatitis (NASH), has a strong genetic component, and the most robust contributor is the patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 encoding the 148M protein sequence variant. We hypothesized that suppressing the expression of the PNPLA3 148M mutant protein would exert a beneficial effect on the entire spectrum of NAFLD.We examined the effects of liver-targeted GalNAc3-conjugated antisense oligonucleotide (ASO)-mediated silencing of Pnpla3 in a knock-in mouse model in which we introduced the human PNPLA3 I148M mutation.ASO-mediated silencing of Pnpla3 reduced liver steatosis (p=0.038) in homozygous Pnpla3 148M/M knock-in mutant mice but not in wild-type littermates fed a steatogenic high-sucrose diet. In mice fed a NASH-inducing diet, ASO-mediated silencing of Pnpla3 reduced liver steatosis score and NAFLD activity score independent of the Pnpla3 genotype, while reductions in liver inflammation score (p=0.018) and fibrosis stage (p=0.031) were observed only in the Pnpla3 knock-in 148M/M mutant mice. These responses were accompanied by reduced liver levels of Mcp1 (p=0.026) and Timp2 (p=0.007) specifically in the mutant knock-in mice. This may reduce levels of chemokine attracting inflammatory cells and increase the collagenolytic activity during tissue regeneration.This study provides the first evidence that a Pnpla3 ASO therapy can improve all features of NAFLD, including liver fibrosis, and suppress the expression of a strong innate genetic risk factor, Pnpla3 148M, which may open up a precision medicine approach in NASH.
  •  
44.
  • Liu, Zhengtao, et al. (author)
  • The effect of the TM6SF2 E167K variant on liver steatosis and fibrosis in patients with chronic hepatitis C : a meta-analysis
  • 2017
  • In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
  • Journal article (peer-reviewed)abstract
    • The impact of Transmembrane 6 superfamily member 2 (TM6SF2) E167K variant, which causes hepatocellular fat retention by altering lipoprotein secretion, on liver damage and metabolic traits in chronic hepatitis C patients is still debated. We performed a systematic review and meta-analysis to clarify this relationship. Four studies with a total of 4325 patients were included. The risk of histologically-determined advanced steatosis, fibrosis, and cirrhosis (but not of severe inflammation) were increased in carriers of the TM6SF2 variant (P < 0.05). Unlike the inconsistent association with steatosis severity, due to the confounding effect of infection by the genotype-3 hepatitis C virus, the TM6SF2 variant was robustly associated with advanced fibrosis (OR = 1.07; 95% confidence interval [CI] = 1.01-1.14) and in particular with cirrhosis (OR = 2.05; 95% CI = 1.39-3.02). Regarding metabolic features, individuals positive for the TM6SF2 variant exhibited 5.8-12.0% lower levels of circulating triglycerides and non-HDL cholesterol (P < 0.05). Carriers of the variant were leaner, but there was high heterogeneity across studies (I-2 = 97.2%). No significant association was observed between the TM6SF2 variant and insulin resistance or hepatitis C viral load (both P > 0.05). In conclusion, the TM6SF2 E167K variant promotes the development of steatosis, fibrosis and cirrhosis in patients with chronic hepatitis C. Conversely, this variant reduces circulating atherogenic lipid fractions.
  •  
45.
  • M, Eslam, et al. (author)
  • Genetics and epigenetics of NAFLD and NASH: Clinical impact.
  • 2018
  • In: Journal of hepatology. - : Elsevier BV. - 1600-0641 .- 0168-8278. ; 68:2, s. 268-279
  • Research review (peer-reviewed)abstract
    • Non-alcoholic fatty liver disease (NAFLD) is now recognised as the most common liver disease worldwide. It encompasses a broad spectrum of conditions, from simple steatosis, through non-alcoholic steatohepatitis, to fibrosis and ultimately cirrhosis and hepatocellular carcinoma. A hallmark of NAFLD is the substantial inter-patient variation in disease progression. NAFLD is considered a complex disease trait such that interactions between the environment and a susceptible polygenic host background determine disease phenotype and influence progression. Recent years have witnessed multiple genome-wide association and large candidate gene studies, which have enriched our understanding of the genetic basis of NAFLD. Notably, the I148M PNPLA3 variant has been identified as the major common genetic determinant of NAFLD. Variants with moderate effect size in TM6SF2, MBOAT7 and GCKR have also been shown to have a significant contribution. The premise for this review is to discuss the status of research into important genetic and epigenetic modifiers of NAFLD progression. The potential to translate the accumulating wealth of genetic data into the design of novel therapeutics and the clinical implementation of diagnostic/prognostic biomarkers will be explored. Finally, personalised medicine and the opportunities for future research and challenges in the immediate post genetics era will be illustrated and discussed.
  •  
46.
  • Macchi, Chiara, et al. (author)
  • Leptin, Resistin, and Proprotein Convertase Subtilisin/Kexin Type 9 - The Role of STAT3
  • 2020
  • In: The American journal of pathology. - : Elsevier BV. - 1525-2191 .- 0002-9440. ; 190:11, s. 2226-2236
  • Journal article (peer-reviewed)abstract
    • In a condition of dysfunctional visceral fat depots, as in the case of obesity, alterations in adipokines levels may be detrimental for the cardiovascular system. The proinflammatory leptin and resistin adipokines have been described as possible links between obesity and atherosclerosis. The present study was aimed at evaluating whether proprotein convertase subtilisin/kexin type 9 (PCSK9), a key regulator of low-density lipoprotein metabolism, is induced by leptin and resistin through the involvement of the inflammatory pathway of signal transducer and activator of transcript 3 (STAT3). In HepG2 cells, leptin and resistin upregulated PCSK9 gene and protein expression as well as the phosphorylation of STAT3. Upon STAT3 silencing, leptin and resistin lost their ability to activate PCSK9. The knock-down of STAT3 did not affect the expression of leptin and resistin receptors as well as that of PCSK9. The analysis of human PCSK9 promoter region showed that the two adipokines raise PCSK9 promoter activity via the involvement of sterol regulatory element motif. In healthy male, a positive association between circulating leptin and PCSK9 levels was found only when BMI was < 25 kg/m2. In conclusion, our study identified STAT3 as one of the molecular regulators of leptin- and resistin-mediated transcriptional induction of PCSK9.
  •  
47.
  • Maglio, Cristina, 1983, et al. (author)
  • The PNPLA3 I148M variant and chronic liver disease: When a genetic mutation meets nutrients
  • 2014
  • In: Food Research International. - : Elsevier BV. - 0963-9969. ; 63, s. 239-243
  • Journal article (peer-reviewed)abstract
    • The isoleucine to methionine substitution at position 148 in the patatin-like phospholipase domain containing 3 protein (PNPLA3; I148M variant, rs738409) is associated with liver fat accumulation and an increased risk of chronic liver disease ranging from hepatitis to hepatocellular carcinoma. This review discusses the interaction between the PNPLA3 I148M variant and obesity/intake of specific nutrients in determining the susceptibility to liver disease. We present the results of several studies showing that obesity or alcohol abuse enhances the effect of the PNPLA3 I148M variant on the liver. We also show that specific nutrients interact with the PNPLA3 I148M variant in modulating liver disease susceptibility. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).
  •  
48.
  • Mancina, Rosellina Margherita, et al. (author)
  • Paradoxical Dissociation Between Hepatic Fat Content and De Novo Lipogenesis Due to PNPLA3 Sequence Variant
  • 2015
  • In: Journal of Clinical Endocrinology & Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 100:5
  • Journal article (peer-reviewed)abstract
    • Context: Nonalcoholic fatty liver disease (NAFLD) is an emerging epidemic disease characterized by increased hepatic fat, due to an imbalance between synthesis and removal of hepatic lipids. In particular, increased hepatic de novo lipogenesis (DNL) is a key feature associated with NAFLD. The genetic variations I148M in PNPLA3 and E167K in TM6SF2 confer susceptibility to NAFLD. Objective: Here we aimed to investigate the contribution of DNL to liver fat accumulation in the PNPLA3 I148M or TM6SF2 E167K genetic determinants of NAFLD. Patients and Methods: The PNPLA3 I148M and TM6SF2 E167K were genotyped in two well-characterized cohorts of Europeans. In the first cohort (Helsinki cohort; n = 88), we directly quantified hepatic DNL using deuterated water. In the second cohort (Milan cohort; n = 63), we quantified the hepatic expression of SREBP1c that we have found previously associated with increased fat content. Liver fat was measured by magnetic resonance proton spectroscopy in the Helsinki cohort, and by histological assessment of liver biopsies in the Milan cohort. Results: PNPLA3 148M was associated with lower DNL and expression of the lipogenic transcription factor SREBP1c despite substantial increased hepatic fat content. Conclusions: Our data show a paradoxical dissociation between hepatic DNL and hepatic fat content due to the PNPLA3 148M allele indicating that increased DNL is not a key feature in all individuals with hepatic steatosis, and reinforces the contribution of decreased mobilization of hepatic triglycerides for hepatic lipid accumulation in subject with the PNPLA3 148M allele.
  •  
49.
  • Mancina, Rosellina Margherita, et al. (author)
  • PNPLA3 148M Carriers with Inflammatory Bowel Diseases Have Higher Susceptibility to Hepatic Steatosis and Higher Liver Enzymes
  • 2016
  • In: Inflammatory Bowel Diseases. - : Oxford University Press (OUP). - 1078-0998. ; 22:1, s. 134-140
  • Journal article (peer-reviewed)abstract
    • Background: Inflammatory bowel diseases (IBD) are characterized by chronic relapsing inflammation of the gastrointestinal tract and encompass Crohn's disease and ulcerative colitis. IBD are often associated with extraintestinal manifestations affecting multiple organs including the liver. Increased levels of serum aminotransferases, possibly related to nonalcoholic fatty liver disease, constitute one of the most frequently described IBD-related liver diseases. The PNPLA3 I148M substitution is a major common genetic determinant of hepatic fat content and progression to chronic liver disease. The aim of this study was to investigate whether carriers of PNPLA3 148M allele with IBD have higher risk of liver steatosis and increase in transaminases levels. Methods: The PNPLA3 I148M (rs738409) genotype was performed by Taqman assays in 158 individuals from Southern Italy (namely, Catanzaro cohort) and in 207 individuals from Northern Italy (namely, Milan cohort) with a definite diagnosis of IBD. Demographic and clinical data and also alanine transaminase levels were collected for both cohorts. The Catanzaro cohort underwent liver evaluation by sonography and liver stiffness and controlled attenuation parameter measurements by transient elastography. Results: Here, we show for the first time that carriers of the PNPLA3 148M allele with IBD have a greater risk of hepatic steatosis (odds ratio, 2.9, and confidence interval, 1.1-7.8), higher controlled attenuation parameter values (P = 0.029), and increased circulating alanine transaminase (P = 0.035) in the Catanzaro cohort. We further confirm the higher alanine transaminase levels in the Milan cohort (P < 0.001). Conclusions: Our results show that PNPLA3 148M carriers with IBD have higher susceptibility to hepatic steatosis and liver damage.
  •  
50.
  • Mancina, Rosellina Margherita, et al. (author)
  • PSD3 downregulation confers protection against fatty liver disease.
  • 2022
  • In: Nature metabolism. - : Springer Science and Business Media LLC. - 2522-5812. ; 4:1, s. 60-75
  • Journal article (peer-reviewed)abstract
    • Fatty liver disease (FLD) is a growing health issue with burdening unmet clinical needs. FLD has a genetic component but, despite the common variants already identified, there is still a missing heritability component. Using a candidate gene approach, we identify a locus (rs71519934) at the Pleckstrin and Sec7 domain-containing 3 (PSD3) gene resulting in a leucine to threonine substitution at position 186 of the protein (L186T) that reduces susceptibility to the entire spectrum of FLD in individuals at risk. PSD3 downregulation by short interfering RNA reduces intracellular lipid content in primary human hepatocytes cultured in two and three dimensions, and in human and rodent hepatoma cells. Consistent with this, Psd3 downregulation by antisense oligonucleotides in vivo protects against FLD in mice fed a non-alcoholic steatohepatitis-inducing diet. Thus, translating these results to humans, PSD3 downregulation might be a future therapeutic option for treating FLD.
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