| 1. |
- Hosseinzadeh, Griffin, et al.
(författare)
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Weak Mass Loss from the Red Supergiant Progenitor of the Type II SN 2021yja
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 935:1
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Meroni, Marica, et al.
(författare)
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Mboat7 down-regulation by hyper-insulinemia induces fat accumulation in hepatocytes.
- 2020
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Ingår i: EBioMedicine. - : Elsevier BV. - 2352-3964. ; 52
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Tidskriftsartikel (refereegranskat)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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| 3. |
- Singh, Mridweeka, et al.
(författare)
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The Fast-evolving Type Ib Supernova SN 2015dj in NGC 7371
- 2021
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 909:2
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Stefania, Grimaudo, et al.
(författare)
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PCSK9 rs11591147 R46L Loss-of-Function Variant Protects Against Liver Damage in Individuals with NAFLD.
- 2021
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Ingår i: Liver international : official journal of the International Association for the Study of the Liver. - : Wiley. - 1478-3231. ; 41:2, s. 321-332
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Tidskriftsartikel (refereegranskat)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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| 5. |
- Baselli, G. A., et al.
(författare)
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Liver transcriptomics highlights interleukin-32 as novel NAFLD-related cytokine and candidate biomarker
- 2020
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Ingår i: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 69, s. 1855-1866
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Baselli, Guido A, et al.
(författare)
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Rare ATG7 genetic variants predispose patients to severe fatty liver disease.
- 2022
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Ingår i: Journal of hepatology. - : Elsevier BV. - 1600-0641 .- 0168-8278. ; 77:3, s. 596-606
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Tidskriftsartikel (refereegranskat)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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| 7. |
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| 8. |
- Bianco, Christina, et al.
(författare)
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Genetic risk scores and personalization of care in fatty liver disease.
- 2021
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Ingår i: Current opinion in pharmacology. - : Elsevier BV. - 1471-4973 .- 1471-4892. ; 61, s. 6-11
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Tidskriftsartikel (refereegranskat)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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| 9. |
- Bianco, Cristina, et al.
(författare)
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Non-invasive stratification of hepatocellular carcinoma risk in non-alcoholic fatty liver using polygenic risk scores.
- 2021
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Ingår i: Journal of hepatology. - : Elsevier BV. - 1600-0641 .- 0168-8278. ; 74:4, s. 775-782
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Tidskriftsartikel (refereegranskat)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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| 10. |
- Bianco, Cristiana, et al.
(författare)
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Predictors of controlled attenuation parameter in metabolic dysfunction
- 2024
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Ingår i: United European Gastroenterology Journal. - 2050-6406 .- 2050-6414. ; 12:3, s. 364-373
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Tidskriftsartikel (refereegranskat)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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