HNF4A protein, human OR C496592 Dotaz Zobrazit nápovědu
Monogenic diabetes is a gateway to precision medicine through molecular mechanistic insight. Hepatocyte nuclear factor 1A (HNF-1A) and HNF-4A are transcription factors that engage in crossregulatory gene transcription networks to maintain glucose-stimulated insulin secretion in pancreatic β cells. Variants in the HNF1A and HNF4A genes are associated with maturity-onset diabetes of the young (MODY). Here, we explored 4 variants in the P2-HNF4A promoter region: 3 in the HNF-1A binding site and 1 close to the site, which were identified in 63 individuals from 21 families of different MODY disease registries across Europe. Our goal was to study the disease causality for these variants and to investigate diabetes mechanisms on the molecular level. We solved a crystal structure of HNF-1A bound to the P2-HNF4A promoter and established a set of techniques to probe HNF-1A binding and transcriptional activity toward different promoter variants. We used isothermal titration calorimetry, biolayer interferometry, x-ray crystallography, and transactivation assays, which revealed changes in HNF-1A binding or transcriptional activities for all 4 P2-HNF4A variants. Our results suggest distinct disease mechanisms of the promoter variants, which can be correlated with clinical phenotype, such as age of diagnosis of diabetes, and be important tools for clinical utility in precision medicine.
- MeSH
- diabetes mellitus 2. typu * genetika metabolismus MeSH
- hepatocytární jaderný faktor 1-alfa * genetika metabolismus MeSH
- hepatocytární jaderný faktor 4 * genetika metabolismus MeSH
- krystalografie rentgenová MeSH
- lidé MeSH
- promotorové oblasti (genetika) * genetika MeSH
- regulace genové exprese MeSH
- vazba proteinů MeSH
- vazebná místa MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
AIMS/HYPOTHESIS: MODY is mainly characterised by an early onset of diabetes and a positive family history of diabetes with an autosomal dominant mode of inheritance. However, de novo mutations have been reported anecdotally. The aim of this study was to systematically revisit a large collection of MODY patients to determine the minimum prevalence of de novo mutations in the most prevalent MODY genes (i.e. GCK, HNF1A, HNF4A). METHODS: Analysis of 922 patients from two national MODY centres (Slovakia and the Czech Republic) identified 150 probands (16%) who came from pedigrees that did not fulfil the criterion of two generations with diabetes but did fulfil the remaining criteria. The GCK, HNF1A and HNF4A genes were analysed by direct sequencing. RESULTS: Mutations in GCK, HNF1A or HNF4A genes were detected in 58 of 150 individuals. Parents of 28 probands were unavailable for further analysis, and in 19 probands the mutation was inherited from an asymptomatic parent. In 11 probands the mutations arose de novo. CONCLUSIONS/INTERPRETATION: In our cohort of MODY patients from two national centres the de novo mutations in GCK, HNF1A and HNF4A were present in 7.3% of the 150 families without a history of diabetes and 1.2% of all of the referrals for MODY testing. This is the largest collection of de novo MODY mutations to date, and our findings indicate a much higher frequency of de novo mutations than previously assumed. Therefore, genetic testing of MODY could be considered for carefully selected individuals without a family history of diabetes.
- MeSH
- diabetes mellitus 2. typu epidemiologie genetika MeSH
- genetická predispozice k nemoci MeSH
- genetické testování MeSH
- hepatocytární jaderný faktor 1-alfa * genetika MeSH
- hepatocytární jaderný faktor 4 * genetika MeSH
- lidé MeSH
- mutace * MeSH
- prevalence MeSH
- protein-serin-threoninkinasy * MeSH
- rodokmen MeSH
- sekvenční analýza DNA MeSH
- Check Tag
- lidé MeSH
- Geografické názvy
- Česká republika MeSH
- Slovenská republika MeSH
AIMS/HYPOTHESIS: MODY is mainly characterised by an early onset of diabetes and a positive family history of diabetes with an autosomal dominant mode of inheritance. However, de novo mutations have been reported anecdotally. The aim of this study was to systematically revisit a large collection of MODY patients to determine the minimum prevalence of de novo mutations in the most prevalent MODY genes (i.e. GCK, HNF1A, HNF4A). METHODS: Analysis of 922 patients from two national MODY centres (Slovakia and the Czech Republic) identified 150 probands (16%) who came from pedigrees that did not fulfil the criterion of two generations with diabetes but did fulfil the remaining criteria. The GCK, HNF1A and HNF4A genes were analysed by direct sequencing. RESULTS: Mutations in GCK, HNF1A or HNF4A genes were detected in 58 of 150 individuals. Parents of 28 probands were unavailable for further analysis, and in 19 probands the mutation was inherited from an asymptomatic parent. In 11 probands the mutations arose de novo. CONCLUSIONS/INTERPRETATION: In our cohort of MODY patients from two national centres the de novo mutations in GCK, HNF1A and HNF4A were present in 7.3% of the 150 families without a history of diabetes and 1.2% of all of the referrals for MODY testing. This is the largest collection of de novo MODY mutations to date, and our findings indicate a much higher frequency of de novo mutations than previously assumed. Therefore, genetic testing of MODY could be considered for carefully selected individuals without a family history of diabetes.
- MeSH
- diabetes mellitus 2. typu epidemiologie genetika MeSH
- genetická predispozice k nemoci MeSH
- genetické testování MeSH
- hepatocytární jaderný faktor 1-alfa genetika MeSH
- hepatocytární jaderný faktor 4 genetika MeSH
- kinázy zárodečného centra MeSH
- lidé MeSH
- mutace * MeSH
- prevalence MeSH
- protein-serin-threoninkinasy genetika MeSH
- rodokmen MeSH
- sekvenční analýza DNA MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- multicentrická studie MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- Slovenská republika MeSH
Elevated serum urate levels cause gout and correlate with cardiometabolic diseases via poorly understood mechanisms. We performed a trans-ancestry genome-wide association study of serum urate in 457,690 individuals, identifying 183 loci (147 previously unknown) that improve the prediction of gout in an independent cohort of 334,880 individuals. Serum urate showed significant genetic correlations with many cardiometabolic traits, with genetic causality analyses supporting a substantial role for pleiotropy. Enrichment analysis, fine-mapping of urate-associated loci and colocalization with gene expression in 47 tissues implicated the kidney and liver as the main target organs and prioritized potentially causal genes and variants, including the transcriptional master regulators in the liver and kidney, HNF1A and HNF4A. Experimental validation showed that HNF4A transactivated the promoter of ABCG2, encoding a major urate transporter, in kidney cells, and that HNF4A p.Thr139Ile is a functional variant. Transcriptional coregulation within and across organs may be a general mechanism underlying the observed pleiotropy between urate and cardiometabolic traits.
- MeSH
- ABC transportér z rodiny G, člen 2 genetika MeSH
- celogenomová asociační studie MeSH
- dna (nemoc) krev epidemiologie genetika MeSH
- genetická predispozice k nemoci MeSH
- genetické lokusy MeSH
- genetické markery * MeSH
- hepatocytární jaderný faktor 1-alfa genetika MeSH
- hepatocytární jaderný faktor 4 genetika MeSH
- játra metabolismus patologie MeSH
- jednonukleotidový polymorfismus * MeSH
- kardiovaskulární nemoci krev epidemiologie genetika MeSH
- kohortové studie MeSH
- kyselina močová krev MeSH
- ledviny metabolismus patologie MeSH
- lidé MeSH
- metabolické nemoci krev epidemiologie genetika MeSH
- nádorové proteiny genetika MeSH
- orgánová specificita MeSH
- signální transdukce * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
HL1-hT1 cell line represents adult human liver stem cells (LSCs) immortalized with human telomerase reverse transcriptase. In this study, HL1-hT1 cells were found to express mesenchymal markers (vimentin, CD73, CD90/THY-1 and CD105) and an early hepatic endoderm marker FOXA2, while not expressing hepatic progenitor (HNF4A, LGR5, α-fetoprotein) or differentiated hepatocyte markers (albumin, transthyretin, connexin 32). In response to microcystin-LR (MC-LR), a time- and concentration-dependent formation of MC-positive protein bands in HL1-hT1 cells was observed. Cellular accumulation of MC-LR occurred most likely via mechanisms independent on organic anion transporting polypeptides (OATPs) or multidrug resistance (MDR) proteins, as indicated (a) by a gene expression analysis of 11 human OATP genes and 4 major MDR genes (MDR1/P-glycoprotein, MRP1, MRP2 and BCRP); (b) by non-significant effects of OATP or MDR1 inhibitors on MC-LR uptake. Accumulation of MC-positive protein bands in HL1-hT1 cells was associated neither with alterations of cell viability and growth, dysregulations of ERK1/2 and p38 kinases, reactive oxygen species formation, induction of double-stranded DNA breaks nor modulations of stress-inducible genes (ATF3, HSP5). It suggests that LSCs might have a selective, MDR1-independent, survival advantage and higher tolerance towards MC-induced cytotoxic, genotoxic or cancer-related events than differentiated adult hepatocytes, fetal hepatocyte or malignant liver cell lines. HL1-hT1 cells provide a valuable in vitro tool for studying effects of toxicants and pharmaceuticals on LSCs, whose important role in the development of chronic toxicities and liver diseases is being increasingly recognized.
- MeSH
- apoptóza účinky léků fyziologie MeSH
- dospělé kmenové buňky účinky léků metabolismus MeSH
- hepatocyty účinky léků metabolismus MeSH
- inhibitory enzymů toxicita MeSH
- játra cytologie účinky léků metabolismus MeSH
- karcinogeny toxicita MeSH
- lidé MeSH
- mikrocystiny toxicita MeSH
- transformované buněčné linie MeSH
- viabilita buněk účinky léků fyziologie MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Klíčová slova
- metabolopatie, hyperinzulinemická hypoglykémie, ABCC8, KCNJ11, GLUD1, HNF4A,
- MeSH
- 3-hydroxyacyl-CoA-dehydrogenasy genetika MeSH
- draslíkové kanály dovnitř usměrňující genetika MeSH
- glutamátdehydrogenasa genetika MeSH
- hepatocytární jaderný faktor 4 genetika MeSH
- kanálopatie diagnóza genetika MeSH
- KATP kanály genetika MeSH
- kojenec MeSH
- lidé MeSH
- mutace * genetika MeSH
- novorozenec MeSH
- protein redukovaného folátového přenašeče genetika MeSH
- receptory sulfonylurey genetika MeSH
- vrozený hyperinzulinismus * diagnóza etiologie genetika MeSH
- Check Tag
- kojenec MeSH
- lidé MeSH
- novorozenec MeSH
CONTEXT: Congenital hyperinsulinism of infancy (CHI) represents a group of heterogeneous disorders characterized by oversecretion of insulin from pancreatic β-cells causing severe hypoglycemia. OBJECTIVE: We studied the distribution of genetic causes of CHI in a Czech population. METHODS: Countrywide collection of patients with CHI included 40 subjects (12 females, median age of diagnosis, 1 wk [interquartile range, 1-612 wk]). We sequenced the ABCC8, KCNJ11, GLUD1, GCK, HADH, UCP2, SLC16A1, HNF4A, and HNF1A genes and investigated structural changes in the ABCC8 gene. We functionally tested novel variants in the ABCC8 gene by Rb(86+) efflux assay and novel variants in the HNF1A gene by transcriptional activation and DNA-binding tests. RESULTS: We found causal mutations in 20 subjects (50%): 19 carried a heterozygous mutation while one patient was homozygous for mutation in the ABCC8 gene. Specifically, we detected 11 mutations (seven novel) in ABCC8, one novel mutation in KCNJ11, five mutations (two novel) in HNF1A, two novel mutations in HNF4A, and one in GCK. We showed a decrease of activation by diazoxide in mutant KATP channels with novel ABCC8 variants by 41-91% (median, 82%) compared with wild-type (WT) channels and reduced transcriptional activity of mutant HNF1A proteins (2.9% for p.Asn62Lysfs93* and 22% for p.Leu254Gln) accompanied by no DNA-binding ability compared with WT HNF1A. CONCLUSION: We detected a higher proportion of heterozygous mutations causing CHI compared with other cohorts probably due to lack of consanguinity and inclusion of milder CHI forms. Interestingly, HNF1A gene mutations represented the second most frequent genetic cause of CHI in the Czech Republic. Based on our results we present a genetic testing strategy specific for similar populations.
- MeSH
- aktivace transkripce MeSH
- DNA genetika MeSH
- dospělí MeSH
- draslíkové kanály dovnitř usměrňující genetika MeSH
- genetická variace MeSH
- hepatocytární jaderný faktor 1-alfa genetika MeSH
- hepatocytární jaderný faktor 4 genetika MeSH
- kohortové studie MeSH
- kojenec MeSH
- lidé MeSH
- mutace genetika MeSH
- novorozenec MeSH
- předškolní dítě MeSH
- protein-serin-threoninkinasy genetika MeSH
- radioizotopy rubidia MeSH
- receptory sulfonylurey genetika MeSH
- rodokmen MeSH
- těhotenství MeSH
- vrozený hyperinzulinismus epidemiologie genetika MeSH
- Check Tag
- dospělí MeSH
- kojenec MeSH
- lidé MeSH
- mužské pohlaví MeSH
- novorozenec MeSH
- předškolní dítě MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
The molecular mechanisms behind the transition from simple steatosis to nonalcoholic steatohepatitis (NASH) in nonalcoholic fatty liver disease (NAFLD) are not clearly understood. This hinders development of effective therapies for treatment and prevention of NASH. In this study expression profiling data from normal, steatosis, and NASH human livers were used to predict transcription factors that are misregulated as mechanistic features of NAFLD progression. Previously-published human NAFLD gene expression profiling data from normal, steatosis, and NASH livers were subjected to transcription factor binding site enrichment analysis. Selected transcription factors that bind enriched transcription factor binding sites were analyzed for changes in expression. Distinct transcription factor binding sites were enriched in genes significantly up- or down-regulated in NASH livers. Those enriched in up-regulated genes were bound by transcription factors such as FOXA, CEBP, and HNF1 family members, while those enriched in down-regulated genes were bound by nuclear receptors involved in xenobiotic sensing and lipid metabolism. Levels of mRNA and protein for selected transcription factors were significantly changed during disease progression. The study indicates that NAFLD progression involves changes in activity or expression of transcription factors that regulate genes involved in hepatic processes known to be altered in NASH. Transcription factors such as PPAR receptors, FoxA family members, and HNF4A might be targeted therapeutically to prevent NAFLD progression.
- MeSH
- down regulace MeSH
- lidé MeSH
- nealkoholová steatóza jater metabolismus MeSH
- progrese nemoci MeSH
- regulace genové exprese fyziologie MeSH
- stanovení celkové genové exprese MeSH
- transkripční faktory metabolismus MeSH
- upregulace MeSH
- vazba proteinů MeSH
- vazebná místa MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Testing for autoantibodies against the zinc transporter ZnT8 (ZnTA) is becoming routine in pediatric diabetes. However, available data are inconclusive when focusing on adult-onset diabetes, including autoimmune diabetes, which does not require insulin at diagnosis (LADA). BASIC PROCEDURES: We examined the ZnTA prevalence and titers and matched them with the clinical phenotype and PTPN22 genotypes of Czech LADA patients who were positive for GADA and/or IA2A and had a fasting C-peptide level >200 pmol/L at diagnosis as well as HNF4A-, GCK- or HNF1A-MODY patients and healthy controls. MAIN FINDINGS: Most LADA patients were negative for ZnTA, and the sensitivity of the assay was only 18-20% for patients with LADA-like progression to insulinotherapy compared to healthy controls. In LADA patients, there was no association between the ZnTA and PTPN22 risk genotypes. LADA patients positive for ZnTA had a lower BMI than those positive for other autoantibodies alone. Importantly, MODY patients were completely negative for ZnTA, and the levels of ZnTA in MODY patients were similar to those in healthy controls. CONCLUSIONS: ZnTA quantification did not improve LADA diagnosis. However, positivity for ZnTA can be used as a negative MODY pre-diagnostic criterion even in the region of Central and East Europe, where other islet cell autoantibodies are common in MODY patients.
- MeSH
- autoprotilátky krev imunologie MeSH
- biologické markery krev MeSH
- diabetes mellitus 1. typu krev farmakoterapie genetika imunologie MeSH
- diabetes mellitus 2. typu krev farmakoterapie genetika imunologie MeSH
- fenotyp MeSH
- genotyp MeSH
- hypoglykemika terapeutické užití MeSH
- inzulin terapeutické užití MeSH
- lidé středního věku MeSH
- lidé MeSH
- progrese nemoci MeSH
- tyrosinfosfatasa nereceptorového typu 22 genetika MeSH
- zinkový transportér 8 krev imunologie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
BACKGROUND: Serum transferrin levels represent an independent predictor of mortality in patients with liver failure. Hepatocyte nuclear factor 4 alpha (HNF4α) is a master regulator of hepatocyte functions. The aim of this study was to explore whether serum transferrin reflects HNF4α activity. METHODS: Factors regulating transferrin expression in alcoholic hepatitis (AH) were assessed via transcriptomic/methylomic analysis as well as chromatin immunoprecipitation coupled to DNA sequencing. The findings were corroborated in primary hepatocytes. Serum and liver samples from 40 patients with advanced liver disease of multiple etiologies were also studied. RESULTS: In patients with advanced liver disease, serum transferrin levels correlated with hepatic transferrin expression (r = 0.51, p = 0.01). Immunohistochemical and biochemical tests confirmed reduced HNF4α and transferrin protein levels in individuals with cirrhosis. In AH, hepatic gene-gene correlation analysis in liver transcriptome revealed an enrichment of HNF4α signature in transferrin-correlated transcriptome while transforming growth factor beta 1 (TGFβ1), tumor necrosis factor α (TNFα), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6) negatively associated with transferrin signature. A key regulatory region in transferrin promoter was hypermethylated in patients with AH. In primary hepatocytes, treatment with TGFβ1 or the HNF4α inhibitor BI6015 suppressed transferrin production, while exposure to TNFα, IL-1β, and IL-6 had no effect. The correlation between hepatic HNF4A and transferrin mRNA levels was also seen in advanced liver disease. CONCLUSIONS: Serum transferrin levels constitute a prognostic and mechanistic biomarker. Consequently, they may serve as a surrogate of impaired hepatic HNF4α signaling and liver failure.
- MeSH
- hepatocytární jaderné faktory metabolismus MeSH
- hepatocyty metabolismus patologie MeSH
- jaterní cirhóza metabolismus MeSH
- lidé středního věku MeSH
- lidé MeSH
- messenger RNA metabolismus MeSH
- metylace DNA MeSH
- nádory jater metabolismus MeSH
- nemoci jater metabolismus patologie MeSH
- promotorové oblasti (genetika) MeSH
- senioři MeSH
- stanovení celkové genové exprese MeSH
- transformující růstový faktor beta1 metabolismus MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH