Добірка наукової літератури з теми "Hepatocyte-Nuclear-Factor -1-A (HNF1A)"

Background/Aims: Maturity onset diabetes of the young (MODY) is a rare condition often misdiagnosed as type 1 diabetes (T1D). The purposes of this study were: to identify any patients followed in a large Turkish cohort as T1D, with an atypical natural history, who may in fact have MODY, and to define the criteria which would indicate patients with likely MODY as early as possible after presentation to allow prompt genetic testing. Methods: Urinary C-peptide/creatinine ratio (UCPCR) was studied in 152 patients having a diagnosis of T1D for at least 3 years. Those with a UCPCR ≥0.2 nmol/mmol were selected for genetic analysis of the Glucokinase (GCK), Hepatocyte nuclear factor 1a (HNF1A), Hepatocyte nuclear factor 4a (HNF4A), and Hepatocyte nuclear factor 1b (HNF1B) genes. This UCPCR cut-off was used because of the reported high sensitivity and specificity. Cases were also evaluated using a MODY probability calculator. Results: Twenty-three patients from 152 participants (15.1%) had a UCPCR indicating persistent insulin reserve. The mean age ± SD of the patients was 13.6 ± 3.6 years (range 8.30–21.6). Of these 23, two (8.7%) were found to have a mutation, one with HNF4A and one with HNF1B mutation. No mutations were detected in the GCK or HNF1A genes. Conclusion: In Turkish children with a diagnosis of T1D but who have persistent insulin reserve 3 years after diagnosis, up to 9% may have a genetic mutation indicating a diagnosis of MODY.

Insulin inhibits the transcription of the microsomal triglyceride transfer protein (MTTP), which plays a pivotal role in lipoprotein assembly and secretion. Here, we provide evidence that a hepatocyte nuclear factor 1 binding element (HNF1A element) within the MTTP promoter serves as a novel negative insulin-responsive element. Deletion/mutation mapping of the MTTP gene promoter identified a modified HNF1A element that is crucial to the negative insulin effect. Chimeric promoter containing this HNF1A element and minimal TEAD1 promoter also responded negatively toward insulin treatment. Gel shift assay demonstrated that HNF1A but not HNF1B binds to this element. Enforced expression of HNF1A was sufficient to reconstitute the negative insulin responsiveness of MTTP promoter in TM4SF1 myocytes that are HNF1A negative. Furthermore, replacing this element with consensus HNF1A element preserved the negative insulin response, suggesting that negative insulin responsiveness is a generic characteristic of HNF1A element. Given that many genes implicated in diabetes contain HNF1A element, the potential regulation of these genes by insulin via HNF1A element may provide important clues for the manifestation and treatment of diabetic metabolic syndromes.

Post-traumatic stress disorder (PTSD) is a complex trauma-related disorder, the etiology and underlying molecular mechanisms of which are still unclear and probably involve different (epi)genetic and environmental factors. Protein N-glycosylation is a common post-translational modification that has been associated with several pathophysiological states, including inflammation and PTSD. Hepatocyte nuclear factor-1α (HNF1A) is a transcriptional regulator of many genes involved in the inflammatory processes, and it has been identified as master regulator of plasma protein glycosylation. The aim of this study was to determine the association between N-glycan levels in plasma and immunoglobulin G, methylation at four CpG positions in the HNF1A gene, HNF1A antisense RNA 1 (HNF1A-AS1), rs7953249 and HNF1A rs735396 polymorphisms in a total of 555 PTSD and control subjects. We found significant association of rs7953249 and rs735396 polymorphisms, as well as HNF1A gene methylation at the CpG3 site, with highly branched, galactosylated and sialyated plasma N-glycans, mostly in patients with PTSD. HNF1A-AS1 rs7953249 polymorphism was also associated with PTSD; however, none of the polymorphisms were associated with HNF1A gene methylation. These results indicate a possible regulatory role of the investigated HNF1A polymorphisms with respect to the abundance of complex plasma N-glycans previously associated with proinflammatory response, which could contribute to the clinical manifestation of PTSD and its comorbidities.

Abstract Mutations in the HNF1A gene cause maturity-onset diabetes of the young type 3, one of the most common genetic causes of non-insulin-dependent (type 2) diabetes mellitus. Although the whole-body Hnf1a-null mouse recapitulates the low insulin levels and high blood glucose observed in human maturity-onset diabetes of the young type 3 patients, these mice also suffer from Laron dwarfism and aminoaciduria, suggesting a role for hepatocyte nuclear factor 1α (Hnf1α) in pathophysiologies distinct from non-insulin-dependent (type 2) diabetes mellitus. In an effort to identify pathways associated with inactivation of Hnf1α, an ultraperformance liquid chromatography coupled to mass spectrometry-based metabolomics study was conducted on urine samples from wild-type and Hnf1a-null mice. An increase in phenylalanine metabolites is in agreement with the known regulation of the phenylalanine hydroxylase gene by Hnf1α. This metabolomic approach also identified urinary biomarkers for three tissue-specific dysfunctions previously unassociated with Hnf1α function. 1) Elevated indolelactate coupled to decreased xanthurenic acid also indicated defects in the indole and kynurenine pathways of tryptophan metabolism, respectively. 2) An increase in the neutral amino acid proline in the urine of Hnf1a-null mice correlated with loss of renal apical membrane transporters of the Slc6a family. 3) Further investigation into the mechanism of aldosterone increase revealed an overactive adrenal gland in Hnf1a-null mice possibly due to inhibition of negative feedback regulation. Although the phenotype of the Hnf1a-null mouse is complex, metabolomics has opened the door to investigation of several physiological systems in which Hnf1α may be a critical regulatory component.

Heterozygous variants in the hepatocyte nuclear factor 1a (HNF1a) cause MODY3 (maturity-onset diabetes of the young, type 3). In this study, we found a case of novel HNF1a p.Gln125* (HNF1a-Q125ter) variant clinically. However, the molecular mechanism linking the new HNF1a variant to impaired islet β-cell function remains unclear. Firstly, a similar HNF1a-Q125ter variant in zebrafish (hnf1a+/−) was generated by CRISPR/Cas9. We further crossed hnf1a+/− with several zebrafish reporter lines to investigate pancreatic β-cell function. Next, we introduced HNF1a-Q125ter and HNF1a shRNA plasmids into the Ins-1 cell line and elucidated the molecular mechanism. hnf1a+/− zebrafish significantly decreased the β-cell number, insulin expression, and secretion. Moreover, β cells in hnf1a+/− dilated ER lumen and increased the levels of ER stress markers. Similar ER-stress phenomena were observed in an HNF1a-Q125ter-transfected Ins-1 cell. Follow-up investigations demonstrated that HNF1a-Q125ter induced ER stress through activating the PERK/eIF2a/ATF4 signaling pathway. Our study found a novel loss-of-function HNF1a-Q125ter variant which induced β-cell dysfunction by activating ER stress via the PERK/eIF2a/ATF4 signaling pathway.

Coronary artery disease is the leading cause of mortality and morbidity in the world. Left main coronary artery disease (LMCAD) is a particularly severe phenotypic form of CAD and has a genetic basis. We hypothesized that some inflammation- and hyperhomocysteinemia-related gene polymorphisms may contribute to LMCAD susceptibility in a Chinese population. We studied the association between polymorphisms in the genes hepatocyte nuclear factor 1 alpha (HNF1A; rs7310409, G/A), C-reactive protein (rs1800947 and rs3093059 T/C), methylenetetrahydrofolate reductase (rs1801133, C/T), and methylenetetrahydrofolate dehydrogenase (rs1076991, A/G) in 402 LMCAD and 804 more peripheral CAD patients in a Chinese population. Genotyping was performed using the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry method. When the HNF1A rs7310409 GG homozygote genotype was used as the reference group, both the individual, GA and AA, and combined GA/AA genotypes were associated with an increased risk of LMCAD. This single nucleotide polymorphism (rs7310409) is strongly associated with plasma CRP levels. In conclusion, the present study provides evidence that the HNF1A rs7310409 G/A functional polymorphism may contribute to the risk of LMCAD.

Abstract Maturity-onset diabetes of the young due to hepatocyte nuclear factor-1 alpha variants (HNF1A-MODY) causes monogenic diabetes. Individuals carrying damaging variants in HNF1A show decreased levels of α1-3,4 fucosylation, as demonstrated on antennary fucosylation of blood plasma N-glycans. The excellent diagnostic performance of this glycan biomarker in blood plasma N-glycans of individuals with HNF1A-MODY has been demonstrated using liquid chromatography methods. Here, we have developed a high-throughput exoglycosidase plate-based assay to measure α1-3,4 fucosylation levels in blood plasma samples. The assay has been optimized and its validity tested using 1000 clinical samples from a cohort of individuals with young-adult onset diabetes including cases with HNF1A-MODY. The α1-3,4 fucosylation levels in blood plasma showed a good differentiating power in identifying cases with damaging HNF1A variants, as demonstrated by receiver operating characteristic curve analysis with the AUC values of 0.87 and 0.95. This study supports future development of a simple diagnostic test to measure this glycan biomarker for application in a clinical setting.

ObjectiveMaturity-onset diabetes of the young caused by hepatocyte nuclear factor-1 alpha (HNF1A) variants (HNF1A-MODY) is a common form of monogenetic diabetes. Although patients with HNF1A-MODY might specifically benefit from sulfonylurea treatment, available methods for screening this specific type of diabetes are not cost-effective. This study was designed to establish an optimized clinical strategy based on multiple biomarkers to distinguish patients with HNF1A-MODY from clinically diagnosed early-onset type 2 diabetes (EOD) for genetic testing in a Chinese population.Research design and methodsA case–control study including 125 non-related young patients with EOD and 15 probands with HNF1A-MODY (cohort 1) was conducted to evaluate reported biomarkers for HNF1A-MODY. A cut-off for the fasting insulin (Fins) level, the 97.5 percentile of 150 healthy subjects with normal components of metabolic syndrome (cohort 2), was used to filter out individuals with obvious insulin resistance (Fins <102 pmol/L). An optimized clinical screening strategy (HNF1A-CSS) was established, and its effectiveness was assessed in another group of 410 young patients with EOD (cohort 3).ResultsIn cohort 1, body mass index (BMI), serum high-density lipoprotein cholesterol (HDL-c) and high-sensitivity C reactive protein (hs-CRP) levels were confirmed to be useful for the differential diagnosis of HNF1A-MODY. In cohort 3, eight probands with HNF1A-MODY were identified. In cohort 3 and young relatives with HNF1A-MODY, meeting three of four criteria (BMI <28 kg/m2, hs-CRP <0.75 mg/L, Fins <102 pmol/L and HDL-c >1.12 mmol/L), the sensitivity and specificity of HNF1A-CSS were 100% and 69.3%, respectively. In the pooled analysis of all young patients, HNF1A-CSS displayed 90.5% sensitivity and 73.6% specificity for identifying patients with HNF1A-MODY among those with clinically diagnosed EOD.ConclusionOur HNF1A-CSS is useful for distinguishing patients with HNF1A-MODY from patients with EOD in a young Chinese population.

The diagnosis of maturity onset diabetes of the young (MODY) is a challenging process in view of the extensive clinical and genetic heterogeneity of the disease. Mutations in the gene encoding hepatocyte nuclear factor 1α ( HNF1A) are responsible for most forms of monogenic diabetes in Northern European populations. Genetic analysis through a combination of whole exome sequencing and Sanger sequencing in three Maltese siblings and their father identified a rare duplication/frameshift mutation in exon 4 of HNF1A that lies within a known mutational hotspot in this gene. In this report, we provide the first description of an HNF1A-MODY3 phenotype in a Maltese family. The findings reported are relevant and new to a regional population, where the epidemiology of atypical diabetes has never been studied before. This report is of clinical interest as it highlights how monogenic diabetes can be misdiagnosed as either type 1, type 2, or gestational diabetes. It also reinforces the need for a better characterisation of monogenic diabetes in Mediterranean countries, particularly in island populations such as Malta with a high prevalence of diabetes.

Le Hepatocyte-nuclear-factor-1-alpha (HNF1A) est un facteur de transcription clé qui régule l'expression de nombreux gènes impliqués dans plusieurs processus métaboliques, notamment dans le foie, l'intestin, le rein et le pancréas. Les mutations hétérozygotes du gène HNF1A sont à l'origine de la forme la plus fréquente de diabète monogénique appelée "Maturity-onset-diabetes-of-the-young" (MODY),communément appelée HNF1A-MODY. Les porteurs de la mutation HNF1A-MODYdéveloppent une légère hyperglycémie dans l'enfance et un diabète plus tard dans la vie en raison d'une perte progressive de la fonction des cellules bêta. Cependant,comme HNF1A n'est pas seulement exprimé dans les cellules bêta du pancréas, mais aussi dans les cellules alpha et delta, ce projet de thèse a été réalisé pour étudier l'effet de la déficience en HNF1A sur la sécrétion paracrine intra-îlot, accompagnée d'altérations dans les gènes codant pour les protéines qui contrôlent l'absorption et le métabolisme du glucose. Pour ce faire, j'ai utilisé des modèles cellulaires et murins de diabète HNF1A-MODY. Le premier modèle cellulaire que j'ai utilisé était la lignée cellulaire INS-1 d'insulinome de rat dérivée de cellules bêta pour surexprimer conditionnellement la mutationP291fsinsC du gène HNF1A (HNF1A-P291fsinsC), en utilisant un système de transactivateur inverse dépendant de la tétracycline. L'expression de la protéine mutante P291fsinsC a été maximalement induite à un niveau significatif par rapport à celle de la Hnf1a endogène en traitant les cellules avec 500 ng/ml de doxycycline pendant (2 à 72 heures). Les cellules INS-1 non induites ont servi de contrôle. Les cellules INS-1 ayant été précédemment signalées comme étant bi-hormonales et n'exprimant pas de marqueurs de cellules alpha, j'ai utilisé ce modèle pour étudier l'effet de la mutation HNF1A-P291fsinsC sur l'expression et la sécrétion des gènes et des protéines de l'insuline et du glucagon. Les analyses cytométriques et d'immunofluorescence ont révélé que les cellules INS-1 étaient principalement composées de cellules insulino-positives, alors que seules quelques cellules coexprimaient l'insuline et le glucagon. Cependant, les cellules bêta matures et immatures ont sécrété de l'insuline et du glucagon en réponse à la stimulation par le glucose. De plus, la surexpression de la protéine mutante HNF1A-P291fsinsC a augmenté l'expression du peptide dérivé du proglucagon et la sécrétion de glucagon en réponse à une stimulation à haute teneur en glucose par rapport aux cellules INS-1 non induites. Ces résultats suggèrent que la protéine Hnf1A est essentielle pour maintenir la maturation et la fonction des cellules bêta.Bien que les cellules INS-1 soient un outil pour étudier la fonction des cellules bêta,elles ne ressemblent pas aux cellules des îlots humains en termes de signalisation paracrine. J'ai donc développé un modèle in vitro en transfectant des îlots humains avec des siRNA ciblant HNF1A (siHNF1A). J'ai utilisé des îlots déficients en HNF1Apour étudier ses effets sur le transport du glucose et la sécrétion hormonale,simultanément à partir des mêmes préparations d'îlots de donneurs. Les transfections de siHNF1A ont réduit de manière significative les niveaux de protéine HNF1A par rapport aux contrôles brouillés, observés par analyse Western Blot. siHNF1A a également réduit l'expression et la sécrétion de la protéine insuline en réponse à une stimulation à haute teneur en glucose. Cela a coïncidé avec une réduction des niveaux de protéine SGLT2, sans changement pour SGLT1, mais avec une légère diminution pour GLUT2. La diminution du SGLT2 était également associée à une augmentation significative de l'expression et de la sécrétion de la protéine glucagon. Ces résultats ont mis en évidence que HNF1A est également un régulateur clé de la fonction des cellules alpha [...]
Hepatocyte-nuclear-factor-1-alpha (HNF1A) is a key transcription factor that regulates the expression of numerous genes involved in several metabolic processes such as in the liver, intestine, kidney, and pancreas. Heterozygous mutations in the HNF1A gene causes the most frequent form of monogenic diabetes called Maturity-onset-diabetes-of-the-young (MODY), commonly referred to as HNF1A-MODY. HNF1A-MODY mutation carriers develop mild-hyperglycemia in childhood and diabetes later in life due to a progressive loss of beta cell function. However, since HNF1A is not only expressed in pancreatic beta cells, but also in alpha and delta cells, this thesis project was carried out to study the effect of HNF1A deficiency on intra-islet paracrine secretion, accompanied by alterations in genes encoding proteins that control glucose uptake and metabolism. To do so, I used cellular and mouse models of HNF1A-MODYdiabetes.The first cellular model I used was the beta-cell-derived rat insulinoma INS-1 cell line to conditionally overexpress the frameshift P291fsinsC mutation in the HNF1A gene(HNF1A-P291fsinsC), using a reverse tetracycline-dependent transactivator system. The expression of the P291fsinsC mutant protein was maximally induced to a significant level over that of endogenous Hnf1a by treating the cells with 500 ng/ml of doxycycline for (2 to 72 hrs). Non-induced INS-1 cells served as a control. Since INS-1 cells were previously reported to be bi-hormonal and did not express alpha cellmarkers, I utilized this model to study the effect of the HNF1A-P291fsinsC mutation on insulin and glucagon gene and protein expression and secretion. Cytometric and immunofluorescence analysis revealed that INS-1 cells comprised mostly of insulinpositivecells, whereas only a few cells co-expressed insulin and glucagon. However,both mature and immature beta cells secreted insulin and glucagon in response to glucose stimulation. Moreover, the overexpression of the HNF1A-P291fsinsC mutant protein increased proglucagon-derived peptide expression and glucagon secretion inresponse to high-glucose stimulation compared to non-induced INS-1 cells. These findings suggest that Hnf1A is essential to maintain beta cell maturation and function.Although INS-1 cells are a valuable tool to study beta-cell function, they do not resemble human islet cells in terms of paracrine signaling. Therefore, I developed an in vitro model by transfecting human islets with siRNAs targeting HNF1A (siHNF1A). I used islets deficient in HNF1A to investigate its effects on glucose transport and hormone secretion, simultaneously from the same donor islet preparations. siHNF1A transfections significantly decreased HNF1A protein levels compared to scrambled controls, observed by Western Blot analysis. siHNF1A also reduced insulin protein expression and secretion in response to high-glucose stimulation. This coincided with reduction in SGLT2 protein levels, with no changes in SGLT1, but a slight decrease inGLUT2. The decrease in SGLT2 was also associated with a significant increase inglucagon protein expression and secretion. These findings highlighted that HNF1A is also a key regulator of alpha cell function.Two HNF1A-MODY mouse models have previously been developed to study the pathogenesis of HNF1A-MODY in vivo. The first was a global Hnf1a-/- knock-out (KO) mouse and the second was a transgenic mouse that overexpresses the dominant-negative human mutant protein specifically in pancreatic beta cells, under the rat insulin promoter [...]