Mistranslation drives alterations in protein levels and the effects of a synonymous variant at the fibroblast growth factor 21 locus

Fibroblast growth factor 21 (FGF21) is a liver-derived hormone with pleiotropic beneficial effects on metabolism. Paradoxically, FGF21 levels are elevated in metabolic diseases. Interventions that restore metabolic homeostasis reduce FGF21. Whether abnormalities in FGF21 secretion or resistance in peripheral tissues is the initiating factor in altering FGF21 levels and function in humans is unknown. A genetic approach is used to help resolve this paradox. The authors demonstrate that the primary event in dysmetabolic phenotypes is the elevation of FGF21 secretion. The latter is regulated by translational reprogramming in a genotype- and context-dependent manner. To relate the findings to tissues outcomes, the minor (A) allele of rs838133 is shown to be associated with increased hepatic inflammation in patients with metabolic associated fatty liver disease. The results here highlight a dominant role for translation of the FGF21 protein to explain variations in blood levels that is at least partially inherited. These results provide a framework for translational reprogramming of FGF21 to treat metabolic diseases

Copy number variation and expression of exportin-4 associates with severity of fibrosis in metabolic associated fatty liver disease

Background Liver fibrosis risk is a heritable trait, the outcome of which is the net deposition of extracellular matrix by hepatic stellate cell-derived myofibroblasts. Whereas nucleotide sequence variations have been extensively studied in liver fibrosis, the role of copy number variations (CNV) in which genes exist in abnormal numbers of copies (mostly due to duplication or deletion) has had limited exploration. Methods The impact of the XPO4 CNV on histological liver damage was examined in a cohort comprised 646 Caucasian patients with biopsy-proven MAFLD and 170 healthy controls. XPO4 expression was modulated and function was examined in human and animal models. Findings Here we demonstrate in a cohort of 816 subjects, 646 with biopsy-proven metabolic associated liver disease (MAFLD) and 170 controls, that duplication in the exportin 4 (XPO4) CNV is associated with the severity of liver fibrosis. Functionally, this occurs via reduced expression of hepatic XPO4 that maintains sustained activation of SMAD3/SMAD4 and promotes TGF-β1-mediated HSC activation and fibrosis. This effect was mediated through termination of nuclear SMAD3 signalling. XPO4 demonstrated preferential binding to SMAD3 compared to other SMADs and led to reduced SMAD3-mediated responses as shown by attenuation of TGFβ1 induced SMAD transcriptional activity, reductions in the recruitment of SMAD3 to target gene promoters following TGF-β1, as well as attenuation of SMAD3 phosphorylation and disturbed SMAD3/SMAD4 complex formation. Interpretation We conclude that a CNV in XPO4 is a critical mediator of fibrosis severity and can be exploited as a therapeutic target for liver fibrosis

Mistranslation Drives Alterations in Protein Levels and the Effects of a Synonymous Variant at the Fibroblast Growth Factor 21 Locus

Fibroblast growth factor 21 (FGF21) is a liver-derived hormone with pleiotropic beneficial effects on metabolism. Paradoxically, FGF21 levels are elevated in metabolic diseases. Interventions that restore metabolic homeostasis reduce FGF21. Whether abnormalities in FGF21 secretion or resistance in peripheral tissues is the initiating factor in altering FGF21 levels and function in humans is unknown. A genetic approach is used to help resolve this paradox. The authors demonstrate that the primary event in dysmetabolic phenotypes is the elevation of FGF21 secretion. The latter is regulated by translational reprogramming in a genotype- and context-dependent manner. To relate the findings to tissues outcomes, the minor (A) allele of rs838133 is shown to be associated with increased hepatic inflammation in patients with metabolic associated fatty liver disease. The results here highlight a dominant role for translation of the FGF21 protein to explain variations in blood levels that is at least partially inherited. These results provide a framework for translational reprogramming of FGF21 to treat metabolic diseases.Peer reviewe

Prevalence estimation of significant fibrosis because of NASH in Spain combining transient elastography and histology

Acord transformatiu CRUE-CSICBackground & Aims: Non-alcoholic fatty liver disease (NAFLD) has become a major public health problem, but the prevalence of fibrosis associated with non-alcoholic steatohepatitis (NASH) is largely unknown in the general population. This study aimed to provide an updated estimation of the prevalence of NASH fibrosis in Spain. Methods: This was an observational, retrospective, cross-sectional, population-based study with merged data from two Spanish datasets: a large (N = 12 246) population-based cohort (ETHON), including transient elastography (TE) data, and a contemporary multi-centric biopsy-proven NASH cohort with paired TE data from tertiary centres (N = 501). Prevalence for each NASH fibrosis stage was estimated by crossing TE data from ETHON dataset with histology data from the biopsy-proven cohort. Results: From the patients with valid TE in ETHON dataset (N = 11 440), 5.61% (95% confidence interval [95% CI]: 2.53-11.97) had a liver stiffness measurement (LSM) ≥ 8 kPa. The proportion attributable to NAFLD (using clinical variables and Controlled Attenuation Parameter) was 57.3% and thus, the estimated prevalence of population with LSM ≥ 8 kPa because of NAFLD was 3.21% (95% CI 1.13-8.75). In the biopsy-proven NASH cohort, 389 patients had LSM ≥ 8 kPa. Among these, 37% did not have significant fibrosis (F2-4). The estimated prevalence of NASH F2-3 and cirrhosis in Spain's adult population were 1.33% (95% CI 0.29-5.98) and 0.70% (95% CI 0.10-4.95) respectively. Conclusions: These estimations provide an accurate picture of the current prevalence of NASH-related fibrosis in Spain and can serve as reference point for dimensioning the therapeutic efforts that will be required as NASH therapies become available

Fibrosis Severity as a Determinant of Cause-Specific Mortality in Patients With Advanced Nonalcoholic Fatty Liver Disease: A Multi-National Cohort Study

Background & Aims Little is known about the natural course of nonalcoholic fatty liver disease (NAFLD) with advanced fibrosis. We describe long-term outcomes and evaluate the effects of clinical and histologic parameters on disease progression in patients with advanced NAFLD. Methods We conducted a multi-national study of 458 patients with biopsy-confirmed NAFLD with bridging fibrosis (F3, n = 159) or compensated cirrhosis (222 patients with Child-Turcotte-Pugh scores of A5 and 77 patients with scores of A6), evaluated from April 1995 through November 2013 and followed until December 2016, death, or liver transplantation at hepatology centers in Spain, Australia, Hong Kong, and Cuba. Biopsies were re-evaluated and scored; demographic, clinical, laboratory, and pathology data for each patient were collected from the time of liver biopsy collection. Cox proportional and competing risk models were used to estimate rates of transplantation-free survival and major clinical events and to identify factors associated with outcomes. Results During a mean follow-up time of 5.5 years (range, 2.7–8.2 years), 37 patients died, 37 received liver transplants, 88 had initial hepatic decompensation events, 41 developed hepatocellular carcinoma, 14 had vascular events, and 30 developed nonhepatic cancers. A higher proportion of patients with F3 fibrosis survived transplantation-free for 10 years (94%; 95% confidence interval [CI], 86%–99%) than of patients with cirrhosis and Child-Turcotte-Pugh A5 (74%; 95% CI, 61%–89%) or Child-Turcotte-Pugh A6 (17%; 95% CI, 6%–29%). Patients with cirrhosis were more likely than patients with F3 fibrosis to have hepatic decompensation (44%; 95% CI, 32%–60% vs 6%, 95% CI, 2%–13%) or hepatocellular carcinoma (17%; 95% CI, 8%–31% vs 2.3%, 95% CI, 1%–12%). The cumulative incidence of vascular events was higher in patients with F3 fibrosis (7%; 95% CI, 3%–18%) than cirrhosis (2%; 95% CI, 0%–6%). The cumulative incidence of nonhepatic malignancies was higher in patients with F3 fibrosis (14%; 95% CI, 7%–23%) than cirrhosis (6%; 95% CI, 2%–15%). Death or transplantation, decompensation, and hepatocellular carcinoma were independently associated with baseline cirrhosis and mild (<33%) steatosis, whereas moderate alcohol consumption was associated with these outcomes only in patients with cirrhosis. Conclusions Patients with NAFLD cirrhosis have predominantly liver-related events, whereas those with bridging fibrosis have predominantly nonhepatic cancers and vascular events

Type 2 Diabetes and Metformin Use Associate With Outcomes of Patients With Non-alcoholic Steatohepatitis-related, Child-Pugh A Cirrhosis

Background & Aims Factors that affect outcomes of patients with non-alcoholic steatohepatitis (NASH) related cirrhosis are unclear. We studied associations of type 2 diabetes, levels of hemoglobin A1c (HbA1c), and use antidiabetic medications with survival and liver-related events in patients with NASH and compensated cirrhosis. Methods We collected data from 299 patients with biopsy-proven NASH with Child-Pugh A cirrhosis from tertiary hospitals in Spain, Australia, Hong Kong, and Cuba, from April 1995 through December 2016. We obtained information on presence of type 2 diabetes, level of HbA1c, and use of antidiabetic medications. Cox proportional and competing risk models were used to estimate and compare rates of transplant-free survival, hepatic decompensation, and hepatocellular carcinoma (HCC). Results Two-hundred and twelve patients had type 2 diabetes at baseline and 8/87 patients developed diabetes during a median follow-up time of 5.1 y (range, 0.5–10.0 y). A lower proportion of patients with diabetes survived the entire follow-up period (38%) than of patients with no diabetes (81%) (adjusted hazard ratio [aHR], 4.23; 95% CI, 1.93–9.29). Higher proportions of patients with diabetes also had hepatic decompensation (51% vs 26% of patients with no diabetes; aHR, 2.03; 95% CI 1.005–4.11) and HCC (25% vs 7% of patients with no diabetes; aHR, 5.42; 95% CI 1.74–16.80). Averaged annual HbA1c levels over time were not associated with outcomes. Metformin use over time was associated with a significant reduction in risk of death or liver transplantation (aHR, 0.41; 95% CI, 0.26–0.45), hepatic decompensation (aHR, 0.80; 95% CI, 0.74–0.97), and HCC (aHR, 0.78; 95% CI, 0.69–0.96). Metformin significantly reduced risk of hepatic decompensation and HCC only in subjects with HbA1c levels above 7.0% (aHR, 0.97; 95% CI, 0.95–0.99 and aHR, 0.67; 95% CI, 0.43–0.94, respectively). Conclusions In an international cohort of patients with biopsy-proven NASH and Child-Pugh A cirrhosis, type 2 diabetes increased risk of death and liver-related outcomes, including HCC. Patients who took metformin had higher rates of survival and lower rates of decompensation and HCC

Metabolomic-Based Noninvasive Serum Test to Diagnose Nonalcoholic Steatohepatitis: Results From Discovery and Validation Cohorts

Nonalcoholic fatty liver disease (NAFLD) is the most common type of chronic liver disease worldwide and includes a broad spectrum of histologic phenotypes, ranging from simple hepatic steatosis or nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH). While liver biopsy is the reference gold standard for NAFLD diagnosis and staging, it has limitations due to its sampling variability, invasive nature, and high cost. Thus, there is a need for noninvasive biomarkers that are robust, reliable, and cost effective. In this study, we measured 540 lipids and amino acids in serum samples from biopsy-proven subjects with normal liver (NL), NAFL, and NASH. Using logistic regression analysis, we identified two panels of triglycerides that could first discriminate between NAFLD and NL and second between NASH and NAFL. These noninvasive tests were compared to blinded histology as a reference standard. We performed these tests in an original cohort of 467 patients with NAFLD (90 NL, 246 NAFL, and 131 NASH) that was subsequently validated in a separate cohort of 192 patients (7 NL, 109 NAFL, 76 NASH). The diagnostic performances of the validated tests showed an area under the receiver operating characteristic curve, sensitivity, and specificity of 0.88 +/- 0.05, 0.94, and 0.57, respectively, for the discrimination between NAFLD and NL and 0.79 +/- 0.04, 0.70, and 0.81, respectively, for the discrimination between NASH and NAFL. When the analysis was performed excluding patients with glucose levels >136 mg/dL, the area under the receiver operating characteristic curve for the discrimination between NASH and NAFL increased to 0.81 +/- 0.04 with sensitivity and specificity of 0.73 and 0.80, respectively. Conclusion: The assessed noninvasive lipidomic serum tests distinguish between NAFLD and NL and between NASH and NAFL with high accuracy.Supported by the National Institutes of Health Blueprint for Neuroscience Research (R01AT001576 to S.C.L., J.M.M.), Agencia Estatal de Investigacion of the Ministerio de Economia, Industria y Competitividad (SAF2014-52097R to J.M.M.), CIBER Hepatic and Digestive Diseases and Instituto de Salud Carlos III (PIE14/0003 to J.M.M.), Etorgai 2015-Gobierno Vasco (ER-2015/00015 to R.M., I.M.A., C.A., A.C.), Plan de Promocion de la Innovacion 2015-Diputacion Foral de Bizkaia (6/12/IN/2015/00131 to A.C., C.A.), National Institute of Diabetes and Digestive and Kidney Diseases (RO1DK81410 to A.J.S.), and Czech Ministry of Health (RVO VFN64165 to L.V.)

The European NAFLD Registry: A real-world longitudinal cohort study of nonalcoholic fatty liver disease.

Non-Alcoholic Fatty Liver Disease (NAFLD), a progressive liver disease that is closely associated with obesity, type 2 diabetes, hypertension and dyslipidaemia, represents an increasing global public health challenge. There is significant variability in the disease course: the majority exhibit only fat accumulation in the liver but a significant minority develop a necroinflammatory form of the disease (non-alcoholic steatohepatitis, NASH) that may progress to cirrhosis and hepatocellular carcinoma. At present our understanding of pathogenesis, disease natural history and long-term outcomes remain incomplete. There is a need for large, well characterised patient cohorts that may be used to address these knowledge gaps and to support the development of better biomarkers and novel therapies. The European NAFLD Registry is an international, prospectively recruited observational cohort study that aims to establish a large, highly-phenotyped patient cohort and linked bioresource. Here we describe the infrastructure, data management and monitoring plans, and the standard operating procedures implemented to ensure the timely and systematic collection of high-quality data and samples. Already recruiting subjects at secondary/tertiary care centres across Europe, the Registry is supporting the European Union IMI2-funded LITMUS 'Liver Investigation: Testing Marker Utility in Steatohepatitis' consortium, which is a major international effort to robustly validate biomarkers that diagnose, risk stratify and/or monitor NAFLD progression and liver fibrosis stage. The European NAFLD Registry has the demonstrable capacity to support research and biomarker development at scale and pace

Metabolic subtypes of patients with NAFLD exhibit distinctive cardiovascular risk profiles

Background and Aims We previously identified subsets of patients with NAFLD with different metabolic phenotypes. Here we align metabolomic signatures with cardiovascular disease (CVD) and genetic risk factors. Approach and Results We analyzed serum metabolome from 1154 individuals with biopsy-proven NAFLD, and from four mouse models of NAFLD with impaired VLDL-triglyceride (TG) secretion, and one with normal VLDL-TG secretion. We identified three metabolic subtypes: A (47%), B (27%), and C (26%). Subtype A phenocopied the metabolome of mice with impaired VLDL-TG secretion; subtype C phenocopied the metabolome of mice with normal VLDL-TG; and subtype B showed an intermediate signature. The percent of patients with NASH and fibrosis was comparable among subtypes, although subtypes B and C exhibited higher liver enzymes. Serum VLDL-TG levels and secretion rate were lower among subtype A compared with subtypes B and C. Subtype A VLDL-TG and VLDL-apolipoprotein B concentrations were independent of steatosis, whereas subtypes B and C showed an association with these parameters. Serum TG, cholesterol, VLDL, small dense LDL5,6, and remnant lipoprotein cholesterol were lower among subtype A compared with subtypes B and C. The 10-year high risk of CVD, measured with the Framingham risk score, and the frequency of patatin-like phospholipase domain-containing protein 3 NAFLD risk allele were lower in subtype A. Conclusions Metabolomic signatures identify three NAFLD subgroups, independent of histological disease severity. These signatures align with known CVD and genetic risk factors, with subtype A exhibiting a lower CVD risk profile. This may account for the variation in hepatic versus cardiovascular outcomes, offering clinically relevant risk stratification.National Institutes of Health (R01DK123763, R01DK119437, HL151328, P30DK52574, P30DK56341, and UL1TR002345); Ministerio de Economía y Competitividad de España (SAF2017-88041-R); Ministerio de Economía y Competitividad de España for the Severo Ochoa Excellence Accreditation (SEV-2016-0644); CIBERehd (Biomedical Research Center in Hepatic and Digestive Diseases) and Netherlands Organization for Applied Scientific Research Program (PMC13 and PMC15); Spanish Carlos III Health Institute (PI15/01132 and PI18/01075); Miguel Servet Program (CON14/00129 and CPII19/00008); Fondo Europeo de Desarrollo Regional, CIBERehd, Department of Industry of the Basque Country (Elkartek: KK-2020/00008); La Caixa Scientific Foundation (HR17-00601); Liver Investigation: Testing Marker Utility in Steatohepatitis consortium funded by the Innovative Medicines Initiative Program of the European Union (777377), which receives support from the European Union’s Horizon 2020 research and innovation programme and EFPIA; Newcastle NIHR Biomedical Research Center; Czech Ministry of Health (RVO-VFN64165/2020); Fondo Nacional De Ciencia y Tecnología de Chile (1191145); and the Comisión Nacional de Investigación, Ciencia y Tecnología (AFB170005, CARE Chile UC); Agencia Nacional de Investigación y Desarrollo (ANID ACE 210009); European Union's Horizon 2020 Research and Innovation Program (825510)

Genetic landscape of 6089 inherited retinal dystrophies affected cases in Spain and their therapeutic and extended epidemiological implications

Inherited retinal diseases (IRDs), defined by dysfunction or progressive loss of photoreceptors, are disorders characterized by elevated heterogeneity, both at the clinical and genetic levels. Our main goal was to address the genetic landscape of IRD in the largest cohort of Spanish patients reported to date. A retrospective hospital-based cross-sectional study was carried out on 6089 IRD affected individuals (from 4403 unrelated families), referred for genetic testing from all the Spanish autonomous communities. Clinical, demographic and familiar data were collected from each patient, including family pedigree, age of appearance of visual symptoms, presence of any systemic findings and geographical origin. Genetic studies were performed to the 3951 families with available DNA using different molecular techniques. Overall, 53.2% (2100/3951) of the studied families were genetically characterized, and 1549 different likely causative variants in 142 genes were identified. The most common phenotype encountered is retinitis pigmentosa (RP) (55.6% of families, 2447/4403). The most recurrently mutated genes were PRPH2, ABCA4 and RS1 in autosomal dominant (AD), autosomal recessive (AR) and X-linked (XL) NON-RP cases, respectively; RHO, USH2A and RPGR in AD, AR and XL for non-syndromic RP; and USH2A and MYO7A in syndromic IRD. Pathogenic variants c.3386G > T (p.Arg1129Leu) in ABCA4 and c.2276G > T (p.Cys759Phe) in USH2A were the most frequent variants identified. Our study provides the general landscape for IRD in Spain, reporting the largest cohort ever presented. Our results have important implications for genetic diagnosis, counselling and new therapeutic strategies to both the Spanish population and other related populations.This work was supported by the Instituto de Salud Carlos III (ISCIII) of the Spanish Ministry of Health (FIS; PI16/00425 and PI19/00321), Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER, 06/07/0036), IIS-FJD BioBank (PT13/0010/0012), Comunidad de Madrid (CAM, RAREGenomics Project, B2017/BMD-3721), European Regional Development Fund (FEDER), the Organización Nacional de Ciegos Españoles (ONCE), Fundación Ramón Areces, Fundación Conchita Rábago and the University Chair UAM-IIS-FJD of Genomic Medicine. Irene Perea-Romero is supported by a PhD fellowship from the predoctoral Program from ISCIII (FI17/00192). Ionut F. Iancu is supported by a grant from the Comunidad de Madrid (CAM, PEJ-2017-AI/BMD7256). Marta del Pozo-Valero is supported by a PhD grant from the Fundación Conchita Rábago. Berta Almoguera is supported by a Juan Rodes program from ISCIII (JR17/00020). Pablo Minguez is supported by a Miguel Servet program from ISCIII (CP16/00116). Marta Corton is supported by a Miguel Servet program from ISCIII (CPII17/00006). The funders played no role in study design, data collection, data analysis, manuscript preparation and/or publication decisions