| 1. |
- Grimaudo, Stefania, et al.
(author)
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NR1H4 rs35724 G>C variant modulates liver damage in nonalcoholic fatty liver disease.
- 2021
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In: Liver international. - : Wiley. - 1478-3231 .- 1478-3223. ; 41:11, s. 2712-2719
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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.
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| 2. |
- Oveis, Jamialahmadi, et al.
(author)
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Exome-wide Association Study on Alanine Aminotransferase Identifies Sequence Variants in the GPAM and APOE Associated with Fatty Liver Disease.
- 2021
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In: Gastroenterology. - : Elsevier BV. - 1528-0012 .- 0016-5085. ; 160:5
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Journal article (peer-reviewed)abstract
- Fatty liver disease (FLD) is a growing epidemic that is expected to be the leading cause of end-stage liver disease within the next decade. Both environmental and genetic factors contribute to the susceptibility of FLD. Several genetic variants contributing to FLD have been identified in exome-wide association studies. However, there is still a missing hereditability indicating that other genetic variants are yet to be discovered.To find genes involved in FLD, we first examined the association of missense and nonsense variants with alanine aminotransferase (ALT) at an exome-wide level in 425,671 participants from the UK Biobank. We then validated genetic variants with liver fat content in 8,930 participants in whom liver fat measurement was available, and replicated two genetic variants in three independent cohorts comprising 2,621 individuals with available liver biopsy.We identified 190 genetic variants independently associated with ALT after correcting for multiple testing with Bonferroni method. The majority of these variants were not previously associated with this trait. Among those associated, there was a striking enrichment of genetic variants influencing lipid metabolism. We identified the variants rs2792751 in GPAM/GPAT1, the gene encoding glycerol-3-phosphate acyltransferase, mitochondrial, and rs429358 in APOE, the gene encoding apolipoprotein E, as robustly associated with liver fat content and liver disease after adjusting for multiple testing. Both genes affect lipid metabolism in the liver.We identified two novel genetic variants in GPAM and APOE that are robustly associated with steatosis and liver damage. These findings may help to better elucidate the genetic susceptibility to FLD onset and progression.
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| 3. |
- Stefania, Grimaudo, et al.
(author)
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PCSK9 rs11591147 R46L Loss-of-Function Variant Protects Against Liver Damage in Individuals with NAFLD.
- 2021
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In: 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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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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