Liver and kidney function in Japanese patients with maturity-onset diabetes of the young

HNF1β bookmarking involves Topoisomerase 1 activation and DNA topology relaxation in mitotic chromatin

HNF1β (HNF1B) is a transcription factor frequently mutated in patients with developmental renal disease. It binds to mitotic chromatin and reactivates gene expression after mitosis, a phenomenon referred to as bookmarking. Using a crosslinking method that circumvents the artifacts of formaldehyde, we demonstrate that HNF1β remains associated with chromatin in a sequence-specific way in both interphase and mitosis. We identify an HNF1β-interacting protein, BTBD2, that enables the interaction and activation of Topoisomerase 1 (TOP1) exclusively during mitosis. Our study identifies a shared microhomology domain between HNF1β and TOP1, where a mutation, found in "maturity onset diabetes of the young" patients, disrupts their interaction. Importantly, HNF1β recruits TOP1 and induces DNA relaxation around HNF1β mitotic chromatin sites, elucidating its crucial role in chromatin remodeling and gene reactivation after mitotic exit. These findings shed light on how HNF1β reactivates target gene expression after mitosis, providing insights into its crucial role in maintenance of cellular identity.

Late-onset Cholestasis with Paucity of Portal Area Secondary to HNF1β Deficiency in Adulthood: A Case Report

Hepatocyte nuclear factor 1β (HNF1β) is essential for biliary development, while its genetic defect triggers the dysplasia of interlobular bile ducts, leading to life-threatening hepatitis and cholestasis. To date, this disorder has mainly been documented in neonates. Here, we report a case of cholestasis in an adult patient caused by a de novo HNF1β mutation. A liver biopsy revealed remarkable shrinkage of the portal area accompanied by a decrease or absence of interlobular bile ducts, veins, and arteries in the portal area. Our case showed that an HNF1β defect could induce late-onset cholestasis with paucity of the portal area in adulthood.

Genotype-phenotype correlations and response to glucose lowering therapy in subjects with HNF1β associated diabetes

AIMS

Molecular defects of hepatic nuclear factor 1β (HNF1β) are associated with multiorgan disease (renal disease, pancreatic hypoplasia, and genital tract anomalies) in addition to diabetes. We examined the phenotypic features, insulin secretory response to glucose, and response to treatment in subjects with HNF1β-MODY (MODY 5).

METHODS

Twelve subjects with HNF1β-MODY were phenotyped in detail. A 2-h oral glucose tolerance test was performed to establish insulin secretory response with glucose, insulin and C-peptide measurements taken at baseline and 30 min intervals. Clinical follow-up occurred bi-annually.

RESULTS

Ten of 12 subjects had diabetes with mean age of onset of 30.2 ± 15.5 years, fasting glucose of 9.7 ± 4.6 mmol/L and HbA1c of 60.9 ± 17.1 mmol/mol (7.7 ± 1.6%). Renal and/or pancreatic morphological abnormalities were found in 9 subjects. Mean fasting C-peptide (0.5 ± 0.4 nmol/L) and AUC C-peptide (1.5 ± 1.0 nmol/L/120 min) were reduced in our cohort with 4 subjects demonstrating marked insulin deficiency. OGIS was reduced at 290.2 ± 67.0 ml min^-1 m^-2. 6/10 subjects were on insulin therapy at initial diagnosis and 8/10 at last clinical follow-up. Mean insulin dose at last clinical follow-up was 0.45 ± 0.23units/kg/day. 5 subjects on insulin were trialled on sulphonylurea therapy, and none was successfully weaned off insulin.

CONCLUSIONS

Diagnosing HNF1β-MODY in a diabetes clinic is challenging due to its variable phenotype and variable age of onset. β-Cell dysfunction and insulin resistance contribute to diabetes in HNF1β-MODY. No subjects successfully transitioned to sulphonylurea. Early initiation of insulin therapy would be suitable to achieve glycaemic control. This emphasizes the importance of genetic testing for monogenic forms of diabetes to guide personalized treatment.

HNF1A：From Monogenic Diabetes to Type 2 Diabetes and Gestational Diabetes Mellitus

Diabetes, a disease characterized by hyperglycemia, has a serious impact on the lives and families of patients as well as on society. Diabetes is a group of highly heterogeneous metabolic diseases that can be classified as type 1 diabetes (T1D), type 2 diabetes (T2D), gestational diabetes mellitus (GDM), or other according to the etiology. The clinical manifestations are more or less similar among the different types of diabetes, and each type is highly heterogeneous due to different pathogenic factors. Therefore, distinguishing between various types of diabetes and defining their subtypes are major challenges hindering the precise treatment of the disease. T2D is the main type of diabetes in humans as well as the most heterogeneous. Fortunately, some studies have shown that variants of certain genes involved in monogenic diabetes also increase the risk of T2D. We hope this finding will enable breakthroughs regarding the pathogenesis of T2D and facilitate personalized treatment of the disease by exploring the function of the signal genes involved. Hepatocyte nuclear factor 1 homeobox A (HNF1α) is widely expressed in pancreatic β cells, the liver, the intestines, and other organs. HNF1α is highly polymorphic, but lacks a mutation hot spot. Mutations can be found at any site of the gene. Some single nucleotide polymorphisms (SNPs) cause maturity-onset diabetes of the young type 3 (MODY3) while some others do not cause MODY3 but increase the susceptibility to T2D or GDM. The phenotypes of MODY3 caused by different SNPs also differ. MODY3 is among the most common types of MODY, which is a form of monogenic diabetes mellitus caused by a single gene mutation. Both T2D and GDM are multifactorial diseases caused by both genetic and environmental factors. Different types of diabetes mellitus have different clinical phenotypes and treatments. This review focuses on HNF1α gene polymorphisms, HNF1A-MODY3, HNF1A-associated T2D and GDM, and the related pathogenesis and treatment methods. We hope this review will provide a valuable reference for the precise and individualized treatment of diabetes caused by abnormal HNF1α by summarizing the clinical heterogeneity of blood glucose abnormalities caused by HNF1α mutation.

Maturity-Onset Diabetes of Young Type 5: Diabetes with Extrapancreatic Features

Objective

This case involves a new-onset diabetes patient diagnosed during pregnancy with the congenital dysplastic right kidney. Case Report. Clinical presentation, biochemical features, imaging in a patient with diabetes diagnosed during pregnancy, and congenital dysplastic right kidney. Discussion. We present a case of a 22-year-old female with the congenital dysplastic right kidney diagnosed with gestational diabetes mellitus after failing a 1-hour oral glucose tolerance test, requiring insulin during pregnancy. Because of the family history of diabetes and morphologic renal abnormalities at young ages on the maternal side of the family, our patient was evaluated for maturity-onset diabetes of adult and was found to have HNF-1β mutation.

Conclusion

This case highlights the importance of considering the diagnosis of maturity-onset diabetes of young and particularly MODY-5 in individuals with extrapancreatic features. MODY-5 should also be considered in a patient undergoing renal transplant at young ages with a family history of morphologic renal abnormalities.

Hnf1b haploinsufficiency differentially affects developmental target genes in a new renal cysts and diabetes mouse model

Heterozygous mutations in HNF1B cause the complex syndrome renal cysts and diabetes (RCAD), characterized by developmental abnormalities of the kidneys, genital tracts and pancreas, and a variety of renal, pancreas and liver dysfunctions. The pathogenesis underlying this syndrome remains unclear as mice with heterozygous null mutations have no phenotype, while constitutive/conditional Hnf1b ablation leads to more severe phenotypes. We generated a novel mouse model carrying an identified human mutation at the intron-2 splice donor site. Unlike heterozygous mice previously characterized, mice heterozygous for the splicing mutation exhibited decreased HNF1B protein levels and bilateral renal cysts from embryonic day 15, originated from glomeruli, early proximal tubules (PTs) and intermediate nephron segments, concurrently with delayed PT differentiation, hydronephrosis and rare genital tract anomalies. Consistently, mRNA sequencing showed that most downregulated genes in embryonic kidneys were primarily expressed in early PTs and the loop of Henle and involved in ion/drug transport, organic acid and lipid metabolic processes, while the expression of previously identified targets upon Hnf1b ablation, including cystic disease genes, was weakly or not affected. Postnatal analyses revealed renal abnormalities, ranging from glomerular cysts to hydronephrosis and, rarely, multicystic dysplasia. Urinary proteomics uncovered a particular profile predictive of progressive decline in kidney function and fibrosis, and displayed common features with a recently reported urine proteome in an RCAD pediatric cohort. Altogether, our results show that reduced HNF1B levels lead to developmental disease phenotypes associated with the deregulation of a subset of HNF1B targets. They further suggest that this model represents a unique clinical/pathological viable model of the RCAD disease.

Insights into the etiology and physiopathology of MODY5/HNF1B pancreatic phenotype with a mouse model of the human disease

Maturity-onset diabetes of the young type 5 (MODY5) is due to heterozygous mutations or deletion of HNF1B. No mouse models are currently available to recapitulate the human MODY5 disease. Here, we investigate the pancreatic phenotype of a unique MODY5 mouse model generated by heterozygous insertion of a human HNF1B splicing mutation at the intron-2 splice donor site in the mouse genome. This Hnf1bsp2/+ model generated with targeted mutation of Hnf1b mimicking the c.544+1G>T (T) mutation identified in humans, results in alternative transcripts and a 38% decrease of native Hnf1b transcript levels. As a clinical feature of MODY5 patients, the hypomorphic mouse model Hnf1bsp2/+ displays glucose intolerance. Whereas Hnf1bsp2/+ isolated islets showed no altered insulin secretion, we found a 65% decrease in pancreatic insulin content associated with a 30% decrease in total large islet volume and a 20% decrease in total β-cell volume. These defects were associated with a 30% decrease in expression of the pro-endocrine gene Neurog3 that we previously identified as a direct target of Hnf1b, showing a developmental etiology. As another clinical feature of MODY5 patients, the Hnf1bsp2/+ pancreases display exocrine dysfunction with hypoplasia. We observed chronic pancreatitis with loss of acinar cells, acinar-to-ductal metaplasia, and lipomatosis, with upregulation of signaling pathways and impaired acinar cell regeneration. This was associated with ductal cell deficiency characterized by shortened primary cilia. Importantly, the Hnf1bsp2/+ mouse model reproduces the pancreatic features of the human MODY5/HNF1B disease, providing a unique in vivo tool for molecular studies of the endocrine and exocrine defects and to advance basic and translational research. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Genetics of 35 blood and urine biomarkers in the UK Biobank

Clinical laboratory tests are a critical component of the continuum of care. We evaluate the genetic basis of 35 blood and urine laboratory measurements in the UK Biobank (n = 363,228 individuals). We identify 1,857 loci associated with at least one trait, containing 3,374 fine-mapped associations and additional sets of large-effect (>0.1 s.d.) protein-altering, human leukocyte antigen (HLA) and copy number variant (CNV) associations. Through Mendelian randomization (MR) analysis, we discover 51 causal relationships, including previously known agonistic effects of urate on gout and cystatin C on stroke. Finally, we develop polygenic risk scores (PRSs) for each biomarker and build 'multi-PRS' models for diseases using 35 PRSs simultaneously, which improved chronic kidney disease, type 2 diabetes, gout and alcoholic cirrhosis genetic risk stratification in an independent dataset (FinnGen; n = 135,500) relative to single-disease PRSs. Together, our results delineate the genetic basis of biomarkers and their causal influences on diseases and improve genetic risk stratification for common diseases.

Maturity-Onset diabetes of the young type 5 treated with the glucagon-like peptide-1 receptor agonist: A case report

RATIONALE

Maturity-onset diabetes of the young type 5 (MODY 5) is a form of monogenic diabetes that is often accompanied by pancreatic dysfunction. To date, no cases of MODY 5 treated with glucagon-like peptide-1 receptor agonist (GLP-1RA) have been reported. We present the first case of MODY 5 treated with GLP-1RA.

PATIENT CONCERNS

A 17-year-old woman, with a history of being operated for congenital ileal atresia at birth, was admitted to our hospital due to hyperglycemia. She had been clinically diagnosed with type 1 diabetes 1 month prior, and administered 14 units of insulin glargine 300 U/mL per day.

DIAGNOSIS

She had hypopotassemia, hypomagnesaemia, pancreatic body, and tail defects, multiple renal cysts, and a family history of diabetes, and urogenital anomaly. Genetic testing revealed heterozygous deletion of hepatocyte nuclear transcription factor-1 beta, leading to the diagnosis of MODY 5.

INTERVENTIONS

The patient was treated with multiple daily insulin injections for 9 days (22 units/d) before administration of GLP-1RA, and then liraglutide was initiated.

OUTCOMES

Liraglutide treatment (0.6 mg/d) alone maintained the patient's glycated hemoglobin level below 7.0% for at least 12 months after discharge. A higher dose, 0.9 mg/d, of liraglutide was not tolerated by the patient due to nausea. Serum levels of C-peptide immunoreactivity were 1.15 ng/mL and 1.91 ng/mL, respectively, after 6 and 12 months of liraglutide therapy.

LESSONS

GLP-1RA might be effective at regulating glucose metabolism by utilizing residual pancreatic endocrine function in patients with MODY 5. Imaging and genetic screening were helpful in the diagnosis of MODY 5.

Prenatal diagnosis of HNF1B-associated renal cysts: Is there a need to differentiate intragenic variants from 17q12 microdeletion syndrome?

OBJECTIVE

17q12 microdeletions containing HNF1B and intragenic variants within this gene are associated with variable developmental, endocrine, and renal anomalies, often already noted prenatally as hyperechogenic/cystic kidneys. Here, we describe prenatal and postnatal phenotypes of seven individuals with HNF1B aberrations and compare their clinical and genetic data to those of previous studies.

METHODS

Prenatal sequencing and postnatal chromosomal microarray analysis were performed in seven individuals with renal and/or neurodevelopmental phenotypes. We evaluated HNF1B-related clinical features from 82 studies and reclassified 192 reported intragenic HNF1B variants.

RESULTS

In a prenatal case, we identified a novel in-frame deletion p.(Gly239del) within the HNF1B DNA-binding domain, a mutational hot spot as demonstrated by spatial clustering analysis and high computational prediction scores. The six postnatally diagnosed individuals harbored 17q12 microdeletions. Literature screening revealed variable reporting of HNF1B-associated clinical traits. Overall, both mutation groups showed a high phenotypic heterogeneity. The reclassification of all previously reported intragenic HNF1B variants provided an up-to-date overview of the mutational spectrum.

CONCLUSIONS

We highlight the value of prenatal HNF1B screening in renal developmental diseases. Standardized clinical reporting and systematic classification of HNF1B variants are necessary for a more accurate risk quantification of prenatal and postnatal clinical features, improving genetic counseling and prenatal decision making.

The clinical and genetic characteristics of permanent neonatal diabetes (PNDM) in the state of Qatar

Background

Neonatal diabetes mellitus (NDM) is a rare condition that occurs within the first six months of life. Permanent NDM (PNDM) is caused by mutations in specific genes that are known for their expression at early and/or late stages of pancreatic beta‐ cell development, and are either involved in beta‐cell survival, insulin processing, regulation, and release. The native population in Qatar continues to practice consanguineous marriages that lead to a high level of homozygosity. To our knowledge, there is no previous report on the genomics of NDM among the Qatari population. The aims of the current study are to identify patients with NDM diagnosed between 2001 and 2016, and examine their clinical and genetic characteristics.

Methods

To calculate the incidence of PNDM, all patients with PNDM diagnosed between 2001 and 2016 were compared to the total number of live births over the 16‐year‐period. Whole Genome Sequencing (WGS) was used to investigate the genetic etiology in the PNDM cohort.

Results

PNDM was diagnosed in nine (n = 9) patients with an estimated incidence rate of 1:22,938 live births among the indigenous Qatari. Seven different mutations in six genes (PTF1A, GCK, SLC2A2, EIF2AK3, INS, and HNF1B) were identified. In the majority of cases, the genetic etiology was part of a previously identified autosomal recessive disorder. Two novel de novo mutations were identified in INS and HNF1B.

Conclusion

Qatar has the second highest reported incidence of PNDM worldwide. A majority of PNDM cases present as rare familial autosomal recessive disorders. Pancreas associated transcription factor 1a (PTF1A) enhancer deletions are the most common cause of PNDM in Qatar, with only a few previous cases reported in the literature.

Expression of mutant mRNA and protein in pancreatic cells derived from MODY3- iPS cells

Maturity-onset diabetes of the young (MODY) is a heterozygous monogenic diabetes; more than 14 disease genes have been identified. However, the pathogenesis of MODY is not fully understood because the patients' pancreatic beta cells are inaccessible. To elucidate the pathology of MODY, we established MODY3 patient-derived iPS (MODY3-iPS) cells using non-integrating Sendai virus (SeV) vector and examined the mutant mRNA and protein of HNF1A (Hepatocyte Nuclear factor 1A) after pancreatic lineage differentiation. Our patient had a cytosine insertion in the HNF1A gene (P291fsinsC) causing frameshift and making a premature termination codon (PTC). We confirmed these MODY3-iPS cells possessed the characteristics of pluripotent stem cells. After we differentiated them into pancreatic beta cells, transcripts of HNF1A gene were cloned and sequenced. We found that P291fsinsC mutant transcripts were much less frequent than wild ones, but they increased after adding cycloheximide (CHX) to the medium. These results suggested that mutant mRNA was destroyed by nonsense-mediated mRNA decay (NMD). Moreover, we were not able to detect any band of mutant proteins in pancreatic lineage cells which were differentiated from MODY3-iPSCs by western blot (WB) analysis. A scarcity of the truncated form of mutant protein may indicate that MODY3 might be caused by a haplo-insufficiency effect rather than a dominant negative manner.

Not only Alagille syndrome. Syndromic paucity of interlobular bile ducts secondary to HNF1β deficiency: a case report and literature review

BACKGROUND

paucity of interlobular bile ducts is an important observation at liver biopsy in the diagnostic work-up of neonatal cholestasis. To date, other than in the Alagille syndrome, syndromic paucity of interlobular bile ducts has been documented in four cholestatic neonates with HFN1β mutations. A syndromic phenotype, known as renal cysts and diabetes syndrome (RCAD), has been identified. This is usually characterized by a wide clinical spectrum, including renal cysts, maturity-onset diabetes of the young, exocrine pancreatic insufficiency, urogenital abnormalities and a not well established liver involvement. Herein we report a novel case of paucity of interlobular bile ducts due to an HFN1β defect.

CASE PRESENTATION

A 5-week-old boy was admitted to our department for cholestatic jaundice with increased gamma-glutamyl transpeptidase and an unremarkable clinical examination. He had been delivered by Caesarian section at 38 weeks' gestation from unrelated parents, with a birth weight of 2600 g (3rd percentile). Screening for cholestatic diseases, including Alagille syndrome, was negative except for a minor pulmonary artery stenosis at echocardiography and a doubt of a thoracic butterfly hemivertebra. The finding of hyperechogenic kidneys with multiple bilateral cortical cysts at ultrasound examination, associated with moderately impaired renal function with proteinuria, polyuria and metabolic acidosis, was suggestive of ciliopathy. A liver biopsy was performed revealing paucity of interlobular bile ducts, thus the diagnosis of Alagille syndrome was reconsidered. Although genetic tests for liver cholestatic diseases were performed with negative results for Alagille syndrome (JAG1 and NOTCH2), a de-novo missense mutation of HNF1β gene was detected. At 18 months of age our patient has persistent cholestasis and his itching is not under satisfactory control.

CONCLUSIONS

Alagille syndrome may not be the only syndrome determining paucity of interlobular bile ducts in neonates presenting with cholestasis and renal impairment, especially in small for gestational age newborns. We suggest that HNF1β deficiency should also be ruled out, taking into consideration HNF1β mutations, together with Alagille syndrome, in next generation sequencing strategies in neonates with cholestasis, renal impairment and/or paucity of interlobular bile ducts at liver biopsy.

Polycystic kidney features of the renal pathology in glycogen storage disease type I: possible evolution to renal neoplasia

Glycogen storage disease type I (GSDI) is a rare genetic pathology characterized by glucose-6 phosphatase (G6Pase) deficiency, translating in hypoglycemia during short fasts. Besides metabolic perturbations, GSDI patients develop long-term complications, especially chronic kidney disease (CKD). In GSDI patients, CKD is characterized by an accumulation of glycogen and lipids in kidneys, leading to a gradual decline in renal function. At a molecular level, the activation of the renin-angiotensin system is responsible for the development of renal fibrosis, eventually leading to renal failure. The same CKD phenotype was observed in a mouse model with a kidney-specific G6Pase deficiency (K.G6pc-/- mice). Furthermore, GSDI patients and mice develop frequently renal cysts at late stages of the nephropathy, classifying GSDI as a potential polycystic kidney disease (PKD). PKDs are genetic disorders characterized by multiple renal cyst formation, frequently caused by the loss of expression of polycystic kidney genes, such as PKD1/2 and PKHD1. Interestingly, these genes are deregulated in K.G6pc-/- kidneys, suggesting their possible role in GSDI cystogenesis. Finally, renal cysts are known to predispose to renal malignancy development. In addition, HNF1B loss is a malignancy prediction factor. Interestingly, Hnf1b expression was decreased in K.G6pc-/- kidneys. While a single case of renal cancer has been reported in a GSDI patient, a clear cell renal carcinoma was recently observed in one K.G6pc-/- mouse (out of 36 studied mice) at a later stage of the disease. This finding highlights the need to further analyze renal cyst development in GSDI patients in order to evaluate the possible associated risk of carcinogenesis, even if the risk might be limited.

Genome-wide methylomic analysis in individuals with HNF1B intragenic mutation and 17q12 microdeletion

Heterozygous mutation of the transcription factor HNF1B is the most common cause of monogenetic developmental renal disease. Disease-associated mutations fall into two categories: HNF1B intragenic mutations and a 1.3 Mb deletion at chromosome 17q12. An increase in neurodevelopmental disorders has been observed in individuals harbouring the 17q12 deletion but not in patients with HNF1B coding mutations.Previous investigations have concentrated on identifying a genetic cause for the increase in behavioural problems seen in 17q12 deletion carriers. We have taken the alternative approach of investigating the DNA methylation profile of these two HNF1B genotype groups along with controls matched for age, gender and diabetes status using the Illumina 450K DNA methylation array (total sample n = 60).We identified a number of differentially methylated probes (DMPs) that were associated with HNF1B-associated disease and passed our stringent experiment-wide significance threshold. These associations were largely driven by the deletion patients and the majority of the significant probes mapped to the 17q12 deletion locus. The observed changes in DNA methylation at this locus were not randomly dispersed and occurred in clusters, suggesting a regulatory mechanism reacting to haploinsufficiency across the entire deleted region.Along with these deletion-specific changes in DNA methylation, we also identified a shared DNA methylation signature in both mutation and deletion patient groups indicating that haploinsufficiency of HNF1B impacts on the methylome of a number of genes, giving further insight to the role of HNF1B.

Metabolic Profiling of Multiorgan Samples: Evaluation of MODY5/RCAD Mutant Mice

In the present study, we performed a metabolomics analysis to evaluate a MODY5/RCAD mouse mutant line as a potential model for HNF1B-associated diseases. Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) of gut, kidney, liver, muscle, pancreas, and plasma samples uncovered the tissue specific metabolite distribution. Orthogonal projections to latent structures discriminant analysis (OPLS-DA) was used to identify the differences between MODY5/RCAD and wild-type mice in each of the tissues. The differences included, for example, increased levels of amino acids in the kidneys and reduced levels of fatty acids in the muscles of the MODY5/RCAD mice. Interestingly, campesterol was found in higher concentrations in the MODY5/RCAD mice, with a four-fold and three-fold increase in kidneys and pancreas, respectively. As expected, the MODY5/RCAD mice displayed signs of impaired renal function in addition to disturbed liver lipid metabolism, with increased lipid and fatty acid accumulation in the liver. From a metabolomics perspective, the MODY5/RCAD model was proven to display a metabolic pattern similar to what would be suspected in HNF1B-associated diseases. These findings were in line with the presumed outcome of the mutation based on the different anatomy and function of the tissues as well as the effect of the mutation on development.

Exocrine pancreatic dysfunction is common in hepatocyte nuclear factor 1β-associated renal disease and can be symptomatic

Background

Heterozygous mutations in the HNF1B gene are the most common monogenic cause of developmental kidney disease. Extrarenal phenotypes frequently occur, including diabetes mellitus and pancreatic hypoplasia; the latter is associated with subclinical exocrine dysfunction. We measured faecal elastase-1 in patients with HNF1B-associated disease regardless of diabetes status and assessed the degree of symptoms associated with pancreatic exocrine deficiency.

Methods

Faecal elastase-1 was measured in 29 patients with a known HNF1B mutation. We defined a low faecal elastase-1 concentration based on the 2.5 percentile of 99 healthy control individuals (410 μg/g stool). Symptoms related to pancreatic exocrine dysfunction were assessed and a subset of the HNF1B cohort (n  =  6) underwent pancreatic imaging.

Results

Faecal elastase-1 was below the 2.5 percentile of the control cohort in 18/29 (62%) patients with HNF1B-associated renal disease. A total of 8/29 (28%) had a measurement suggestive of exocrine pancreatic insufficiency at  <200 μg/g stool; of these, 3 suffered with abdominal pain, loose stools and/or unintentional weight loss. All three experienced symptomatic improvement and weight gain after commencing pancreatic enzyme replacement therapy. Faecal elastase-1 was low in 7/15 (47%) HNF1B patients without diabetes compared with 11/14 (79%) of those with diabetes (P  =  0.1).

Conclusions

Faecal elastase-1 deficiency is a common feature of HNF1B-associated renal disease even when diabetes is not present and pancreatic exocrine deficiency may be more symptomatic than previously suggested. Faecal elastase-1 should be measured in all patients with known HNF1B-associated disease complaining of chronic abdominal pain, loose stools or unintentional weight loss. The discovery of a low faecal elastase-1 concentration in individuals with developmental kidney disease of uncertain cause should prompt referral for HNF1B genetic testing.

Quantitative Evaluation of Serum Proteins Uncovers a Protein Signature Related to Maturity-Onset Diabetes of the Young (MODY)

Maturity-onset diabetes of the young (MODY) is an inherited monogenic type of diabetes. Genetic mutations in MODY often cause nonsynonymous changes that directly lead to the functional distortion of proteins and the pathological consequences. Herein, we proposed that the inherited mutations found in a MODY family could cause a disturbance of protein abundance, specifically in serum. The serum samples were collected from a Uyghur MODY family through three generations, and the serum proteins after depletion treatment were examined by quantitative proteomics to characterize the MODY-related serum proteins followed by verification using target quantification of proteomics. A total of 32 serum proteins were preliminarily identified as the MODY-related. Further verification test toward the individual samples demonstrated the 12 candidates with the significantly different abundance in the MODY patients. A comparison of the 12 proteins among the sera of type 1 diabetes, type 2 diabetes, MODY, and healthy subjects was conducted and revealed a protein signature related with MODY composed of the serum proteins such as SERPINA7, APOC4, LPA, C6, and F5.

Diabetes, Associated Clinical Spectrum, Long-term Prognosis, and Genotype/Phenotype Correlations in 201 Adult Patients With Hepatocyte Nuclear Factor 1B (HNF1B) Molecular Defects

OBJECTIVE

Molecular defects of hepatocyte nuclear factor 1B (HNF1B) are associated with a multiorgan disease, including diabetes (maturity-onset diabetes of the young 5) and kidney abnormalities. The HNF1B syndrome is related to HNF1B mutations or to a 17q12 deletion spanning 15 genes, including HNF1B. Here, we described HNF1B-related diabetes and associated phenotypes and assessed genotype/phenotype correlations at diagnosis and in the long-term.

RESEARCH DESIGN AND METHODS

This multicenter retrospective cohort study included 201 patients, aged 18 years or older at follow-up, with HNF1B mutations (n = 101) or deletion (n = 100).

RESULTS

Diabetes was present in 159 patients. At diagnosis, clinical symptoms of diabetes were present in 67 of 144 patients and HNF1B renal disease in 64 of 102. Although responsiveness to sulfonylureas/repaglinide was observed in 29 of the 51 tested, 111 of 140 patients (79%) were treated with insulin at follow-up. Diabetic retinopathy and/or neuropathy were present in 46 of 114 patients. Renal cysts were present in 122 of 166 patients, chronic kidney disease stages 3-4 (CKD3-4) in 75 of 169 (44%), and end-stage renal disease (ESRD) in 36 of 169 (21%). Compared with the patients with mutations, those with HNF1B deletion less often had CKD3-4/ESRD at diagnosis (11 of 43 vs. 27 of 35, P < 10^-4) and in the long term (40 of 78 vs. 71 of 91, P = 0.0003). They were leaner and more frequently treated with insulin.

CONCLUSIONS

In patients with HNF1B syndrome, diabetes complications, cardiovascular risk factors, CKD3-4, and ESRD are highly prevalent. At diabetes diagnosis, the presence of morphological and/or functional kidney disease may help etiological diagnosis. Genotype/phenotype correlations may have implications for the care and the prognosis of these patients.

MODY in Ukraine: genes, clinical phenotypes and treatment

BACKGROUND

Maturity-onset diabetes of the young (MODY) has not been previously studied in Ukraine. We investigated the genetic etiology in a selected cohort of patients with diabetes diagnosed before 18 years of age, and in their family members.

METHODS

Genetic testing of the most prevalent MODY genes (GCK, HNF1A, HNF4A, HNF1B and INS) was undertaken for 36 families (39 affected individuals) by Sanger or targeted next generation sequencing.

RESULTS

A genetic diagnosis of MODY was made in 15/39 affected individuals from 12/36 families (33%). HNF1A and HNF4A MODY were the most common subtypes, accounting for 9/15 of MODY cases. Eight patients with HNF1A or HNF4A MODY and inadequate glycemic control were successfully transferred to sulfonylureas. Median HbA1c decreased from 67 mmol/mol (range 58-69) to 47 mmol/mol (range 43-50) (8.3% [7.5-8.5] to 6.4% [6.1-6.7]) 3 months after transfer (p=0.006).

CONCLUSIONS

Genetic testing identified pathogenic HNF1A and HNF4A variants as the most common cause of MODY in Ukraine. Transfer to sulfonylureas substantially improved the glycemic control of these patients.

Biliary Anomalies in Patients With HNF1B Diabetes

CONTEXT

The clinical spectrum of organogenetic anomalies associated with HNF1B mutations is heterogeneous. Besides cystic kidney disease, diabetes, and various other manifestations, odd cases of mainly neonatal and posttransplantation cholestasis have been described. The biliary phenotype is incompletely defined.

OBJECTIVE

To systematically characterize HNF1B-related anomalies in the bile ducts by imaging with magnetic resonance imaging (MRI) or magnetic resonance cholangiopancreatography (MRCP).

SETTING AND PATIENTS

Fourteen patients with HNF1B mutations in the catchment area of the Helsinki University Hospital were evaluated with upper abdominal MRI and MRCP. Blood samples and clinical history provided supplemental data on the individual phenotype.

MAIN OUTCOME MEASURE(S)

Structural anomalies in the biliary system, medical history of cholestasis, other findings in abdominal organs, diabetes and antihyperglycemic treatment, hypomagnesemia, and hyperuricemia.

RESULTS

Structural anomalies of the bile ducts were found in seven of 14 patients (50%). Six patients had choledochal cysts, which are generally considered premalignant.

CONCLUSIONS

Structural anomalies of the biliary system were common in HNF1B mutation carriers. The malignant potential of HNF1B-associated choledochal cysts warrants further studies.

Loss of transcriptional activation of the potassium channel Kir5.1 by HNF1β drives autosomal dominant tubulointerstitial kidney disease

Hepatocyte nuclear factor 1 homeobox B (HNF1β) is an essential transcription factor for the development and functioning of the kidney. Mutations in HNF1β cause autosomal dominant tubulointerstitial kidney disease characterized by renal cysts and maturity-onset diabetes of the young (MODY). Moreover, these patients suffer from a severe electrolyte phenotype consisting of hypomagnesemia and hypokalemia. Until now, genes that are regulated by HNF1β are only partially known and do not fully explain the phenotype of the patients. Therefore, we performed chIP-seq in the immortalized mouse kidney cell line mpkDCT to identify HNF1β binding sites on a genome-wide scale. In total 7,421 HNF1β-binding sites were identified, including several genes involved in electrolyte transport and diabetes. A highly specific and conserved HNF1β site was identified in the promoter of Kcnj16 that encodes the potassium channel Kir5.1. Luciferase-promoter assays showed a 2.2-fold increase in Kcnj16 expression when HNF1β was present. Expression of the Hnf1β p.Lys156Glu mutant, previously identified in a patient with autosomal dominant tubulointerstitial kidney disease, did not activate Kcnj16 expression. Knockdown of Hnf1β in mpkDCT cells significantly reduced the appearance of Kcnj16 (Kir5.1) and Kcnj10 (Kir4.1) by 38% and 37%, respectively. These results were confirmed in a HNF1β renal knockout mouse which exhibited downregulation of Kcnj16, Kcnj10 and Slc12a3 transcripts in the kidney by 78%, 83% and 76%, respectively, compared to HNF1β wild-type mice. Thus, HNF1β is a transcriptional activator of Kcnj16. Hence, patients with HNF1β mutations may have reduced Kir5.1 activity in the kidney, resulting in hypokalemia and hypomagnesemia.

Genetic Syndromes Affecting Kidney Development

Renal anomalies are common birth defects that may manifest as a wide spectrum of anomalies from hydronephrosis (dilation of the renal pelvis and calyces) to renal aplasia (complete absence of the kidney(s)). Aneuploidies and mosaicisms are the most common syndromes associated with CAKUT. Syndromes with single gene and renal developmental defects are less common but have facilitated insight into the mechanism of renal and other organ development. Analysis of underlying genetic mutations with transgenic and mutant mice has also led to advances in our understanding of mechanisms of renal development.

A prospective study to evaluate the efficacy and safety of oral acetyl-L-carnitine for the treatment of chemotherapy-induced peripheral neuropathy

The present study aimed to evaluate the efficacy and safety of acetyl-L-carnitine (ALC) for the treatment of chemotherapy-induced peripheral neuropathy (CIPN). The study was carried out as a prospective, randomized, double-blind, placebo-controlled and paralleled clinical study. A total of 239 patients with CIPN were selected as the study subjects. Of the 239 subjects, 118 subjects received 3 g/day ALC orally for 8 weeks and 121 received a placebo. The primary endpoint was improvement of peripheral neuropathy by at least one grade. Patient status was assessed at week 4, 8 and 12 after enrollment into the study. In both the full analysis set (FAS) and the per-protocol set (PPS), peripheral sensory neuropathy was significantly ameliorated in the ALC group with 50.5 and 51.6% patients meeting the primary endpoint at week 8, compared with 24.1 and 23.1% of patients in the placebo group (P<0.001 in both sets). Secondary endpoints, such as the nerve electrophysiological examination and the Karnofsky physical score were also significantly improved in patients receiving ALC treatment, as compared with the placebo group (FAS, P=0.0463 and P=0.022; PPS, P=0.0076 and P=0.0064, respectively). Cancer-associated fatigue was significantly alleviated following ALC treatment in the PPS (P=0.0135). In the safety analysis set, the difference in adverse events incidence between the two groups was not statistically significant (P=0.3903). There were only two severe adverse events in the ALC group, which were not associated with the effect of ALC. In conclusion, the results of the present study demonstrated that in Chinese patients with cancer, oral administration of ALC is effective at ameliorating peripheral sensory neuropathy induced by chemotherapy, as well as reducing of cancer-associated fatigue and improving physical conditions.

Crosstalk of HNF4α with extracellular and intracellular signaling pathways in the regulation of hepatic metabolism of drugs and lipids

The liver is essential for survival due to its critical role in the regulation of metabolic homeostasis. Metabolism of xenobiotics, such as environmental chemicals and drugs by the liver protects us from toxic effects of these xenobiotics, whereas metabolism of cholesterol, bile acids (BAs), lipids, and glucose provide key building blocks and nutrients to promote the growth or maintain the survival of the organism. As a well-established master regulator of liver development and function, hepatocyte nuclear factor 4 alpha (HNF4α) plays a critical role in regulating a large number of key genes essential for the metabolism of xenobiotics, metabolic wastes, and nutrients. The expression and activity of HNF4α is regulated by diverse hormonal and signaling pathways such as growth hormone, glucocorticoids, thyroid hormone, insulin, transforming growth factor-β, estrogen, and cytokines. HNF4α appears to play a central role in orchestrating the transduction of extracellular hormonal signaling and intracellular stress/nutritional signaling onto transcriptional changes in the liver. There have been a few reviews on the regulation of drug metabolism, lipid metabolism, cell proliferation, and inflammation by HNF4α. However, the knowledge on how the expression and transcriptional activity of HNF4α is modulated remains scattered. Herein I provide comprehensive review on the regulation of expression and transcriptional activity of HNF4α, and how HNF4α crosstalks with diverse extracellular and intracellular signaling pathways to regulate genes essential in liver pathophysiology.

Pancreatic developmental defect evaluated by celiac artery angiography in a patient with MODY5

The hepatocyte nuclear factor 1β gene (HNF1B) is responsible for maturity-onset diabetes of the young type 5 (MODY5), which is characterized by early-onset diabetes mellitus and urogenital malformations. HNF1B is expressed during visceral endoderm formation. We identified a disruption of the great pancreatic artery in a patient with MODY5 with no pancreatic body or tail. Our finding supports the significance of HNF1B in the development of the pancreas.

Chromosome 17q12 microdeletions but not intragenic HNF1B mutations link developmental kidney disease and psychiatric disorder

Heterozygous mutations of the HNF1B gene are the commonest known monogenic cause of developmental kidney disease. Half of patients have a deletion (approximately 1.3 Mb) of chromosome 17q12, encompassing HNF1B plus 14 additional genes. This 17q12 deletion has been linked with an increased risk of neurodevelopmental disorders, such as autism. Here we compared the neurodevelopmental phenotype of 38 patients with HNF1B-associated renal disease due to an intragenic mutation in 18 patients or due to 17q12 deletion in 20 patients to determine whether haploinsufficiency of HNF1B is responsible for the neurodevelopmental phenotype. Significantly, brief behavioral screening in children with the deletion showed high levels of psychopathology and its impact. Eight individuals (40%) with a deletion had a clinical diagnosis of a neurodevelopmental disorder compared to none with an intragenic mutation. The 17q12 deletions were also associated with more autistic traits. Two independent clinical geneticists were able to predict the presence of a deletion with a sensitivity of 83% and specificity of 79% when assessing facial dysmorphic features as a whole. Thus, the 17q12 deletions but not HNF1B intragenic mutations are associated with neurodevelopmental disorders. Hence, the HNF1B gene is not involved in the neurodevelopmental phenotype of these patients. Nephrologists need to be aware of this association to ensure appropriate referral to psychiatric services.

Structure-function studies of HNF1A (MODY3) gene mutations in South Indian patients with monogenic diabetes

Maturity-onset diabetes of the young (MODY) is a genetically heterogeneous monogenic form of diabetes characterized by onset of diabetes below 25 years of age, autosomal dominant mode of inheritance and primary defect in insulin secretion. Mutations in the gene (HNF1A) encoding transcription factor hepatocyte nuclear factor 1A (HNF-1A) results in one of the most common forms of MODY (MODY3). HNF-1A is mainly enriched in pancreatic β-cells and hepatocytes and important for organ development and normal pancreatic function. We here report on the functional interrogation of eight missense HNF1A mutations associated with MODY3 in South Indian subjects, and the contributing effect of common variant (S487N) within HNF1A. Of the eight mutations, three mutations (p.R171G, p.G245R and p.R263H), in particular, affected HNF-1A function in transfected HeLa cells by reducing both transcriptional activity and nuclear localization, possibly due to disruption of the integrity of the three dimensional structure. The common variant p.S487N contributed further to the loss-of-function of p.R271Q (p.R271Q+p.S487N double mutant), in vitro, on both activity and localization. Our data on the first functional study of HNF1A mutations in South India subjects confers that the defect of the HNF-1A mutant proteins are responsible for MODY3 diabetes in these patients.

Assessment of the HNF1B Score as a Tool to Select Patients for HNF1B Genetic Testing

Background/Aims

Diagnosing hepatocyte nuclear factor 1β (HNF1B)-related disease is a challenging task due to the phenotypic variability and frequent absence of a family history. An HNF1B score has recently been developed to help select appropriate patients for genetic testing with a negative predictive value (NPV) of 99%. We aimed at testing the clinical utility of this score in a large number of referrals for HNF1B genetic testing to the UK diagnostic testing service for the HNF1B gene.

Methods

An HNF1B score was assigned for 686 UK referrals for HNF1B genetic testing using clinical information available at referral. The performance of the score was evaluated by receiver-operating characteristic curve analysis. The relative discriminatory ability of different clinical features for making a genetic diagnosis of HNF1B-related disease were estimated in the UK dataset alone and pooled with French data.

Results

The HNF1B score discriminated between patients with and without a mutation reasonably well with an area under the curve of 0.72. Applying the suggested cut-off score of ≥8 gave a NPV of 85%. In a pooled analysis, antenatal renal abnormalities, renal hyperechogenicity and cysts were discriminatory in children, whereas renal hypoplasia and cysts were discriminatory in adults. Pancreatic abnormalities were discriminatory in both, whereas other extra-renal characteristics had a large effect size only in adults.

Conclusion

The HNF1B score was discriminatory for HNF1B mutations in a large cohort of individuals tested in a single UK centre. The lower NPV (85 vs. 99%) reduces its clinical utility in selecting patients for HNF1B genetic testing, although validation in a prospective cohort is required.

Establishment of maturity-onset diabetes of the young-induced pluripotent stem cells from a Japanese patient

Maturity-onset diabetes of the young (MODY) is a heterozygous monogenic diabetes; more than 13 disease genes have been identified. However, the pathogenesis of MODY is not fully understood, because the pancreatic β-cells of the patients are inaccessable. Therefore, we attempted to establish MODY patient-derived induced pluripotent stem cells (MODY-iPS) cells to investigate the pathogenic mechanism of MODY by inducing pancreatic β-cells. We established MODY5-iPS cells from a Japanese patient with MODY5 (R177X), and confirmed that MODY5-iPS cells possessed the characteristics of pluripotent stem cells. In the course of differentiation from MODY5-iPS cells into pancreatic β-cells, we examined the disease gene, HNF1B messenger ribonucleic acid. We found that the amount of R177X mutant transcripts was much less than that of wild ones, but they increased after adding cycloheximide to the medium. These results suggest that these R177X mutant messenger ribonucleic acids are disrupted by nonsense-mediated messenger ribonucleic acid decay in MODY-iPS cells during the developmental stages of pancreatic β-cells.

Roles of HNF1α and HNF4α in pancreatic β-cells: lessons from a monogenic form of diabetes (MODY)

Mutations in the genes encoding hepatocyte nuclear factor (HNF)1α and HNF4α cause a monogenic form of diabetes mellitus known as maturity-onset diabetes of the young (MODY). The primary cause of MODY is an impairment of glucose-stimulated insulin secretion by pancreatic β-cells, indicating the important roles of HNF1α and HNF4α in β-cells. Large-scale genetic studies have clarified that the common variants of HNF1α and HNF4α genes are also associated with type 2 diabetes, suggesting that they are involved in the pathogenesis of both diseases. Recent experimental studies revealed that HNF1α controls both β-cell function and growth by regulating target genes such as glucose transporter 2, pyruvate kinase, collectrin, hepatocyte growth factor activator, and HNF4α. In contrast, HNF4α mainly regulates the function of β-cells. Although direct target genes of HNF4α in β-cells are largely unknown, we recently identified Anks4b as a novel target of HNF4α that regulates β-cell susceptibility to endoplasmic reticulum stress. Studies of MODY have led to a better understanding of the molecular mechanism of glucose-stimulated insulin secretion by pancreatic β-cells.

Low serum level of high-sensitivity C-reactive protein in a Japanese patient with maturity-onset diabetes of the young type 3 (MODY3)

High-sensitivity C-reactive protein (hs-CRP) levels in European populations are lower in patients with maturity-onset diabetes of the young type 3 (MODY3) than in those with type 2 diabetes. hs-CRP levels have been suggested to be useful for discriminating MODY3 from type 2 diabetes. As hs-CRP levels are influenced by various factors including race and body mass index, it is worthwhile to examine whether hs-CRP can serve as a biomarker for MODY3 in Japanese. Here we describe the case of a Japanese MODY3 patient with a nonsense mutation in the HNF1A gene. Two measurements showed consistently lower hs-CRP levels (<0.05 and 0.09 mg/L) than in Japanese patients with type 1 and type 2 diabetes. Hepatic expression of Crp messenger ribonucleic acid was significantly decreased in Hnf1a knockout mice. The hs-CRP level might be a useful biomarker for MODY3 in both Japanese and European populations.

Assessing the phenotypic effects in the general population of rare variants in genes for a dominant Mendelian form of diabetes

Genome sequencing can identify individuals in the general population who harbor rare coding variants in genes for Mendelian disorders and who may consequently have increased disease risk. Previous studies of rare variants in phenotypically extreme individuals display ascertainment bias and may demonstrate inflated effect-size estimates. We sequenced seven genes for maturity-onset diabetes of the young (MODY) in well-phenotyped population samples (n = 4,003). We filtered rare variants according to two prediction criteria for disease-causing mutations: reported previously in MODY or satisfying stringent de novo thresholds (rare, conserved and protein damaging). Approximately 1.5% and 0.5% of randomly selected individuals from the Framingham and Jackson Heart Studies, respectively, carry variants from these two classes. However, the vast majority of carriers remain euglycemic through middle age. Accurate estimates of variant effect sizes from population-based sequencing are needed to avoid falsely predicting a substantial fraction of individuals as being at risk for MODY or other Mendelian diseases.

Mutations in the genes encoding the transcription factors hepatocyte nuclear factor 1 alpha and 4 alpha in maturity-onset diabetes of the young and hyperinsulinemic hypoglycemia

Maturity-onset diabetes of the young (MODY) is a monogenic disorder characterized by autosomal dominant inheritance of young-onset (typically <25 years), noninsulin-dependent diabetes due to defective insulin secretion. MODY is both clinically and genetically heterogeneous with mutations in at least 10 genes. Mutations in the HNF1A gene encoding hepatocyte nuclear factor-1 alpha are the most common cause of MODY in most adult populations studied. The number of different pathogenic HNF1A mutations totals 414 in 1,247 families. Mutations in the HNF4A gene encoding hepatocyte nuclear factor-4 alpha are a rarer cause of MODY with 103 different mutations reported in 173 families to date. Sensitivity to treatment with sulfonylurea tablets is a feature of both HNF1A and HNF4A mutations. The HNF4A MODY phenotype has been expanded by the reports of macrosomia in ∼50% of babies, and more rarely, neonatal hyperinsulinemic hypoglycemia. The identification of an HNF1A or HNF4A gene mutation has important implications for clinical management in diabetes and pregnancy, but MODY is significantly underdiagnosed. Current research is focused on identifying biomarkers and developing probability models to identify those patients most likely to have MODY, until next generation sequencing technology enables cost-effective gene analysis for all patients with young onset diabetes.

Genetically modified pig models for human diseases

Genetically modified animal models are important for understanding the pathogenesis of human disease and developing therapeutic strategies. Although genetically modified mice have been widely used to model human diseases, some of these mouse models do not replicate important disease symptoms or pathology. Pigs are more similar to humans than mice in anatomy, physiology, and genome. Thus, pigs are considered to be better animal models to mimic some human diseases. This review describes genetically modified pigs that have been used to model various diseases including neurological, cardiovascular, and diabetic disorders. We also discuss the development in gene modification technology that can facilitate the generation of transgenic pig models for human diseases.

Clinical features and treatment of maturity onset diabetes of the young (MODY)

Maturity onset diabetes of the young (MODY) is a heterogeneous group of disorders that result in β-cell dysfunction. It is rare, accounting for just 1%-2% of all diabetes. It is often misdiagnosed as type 1 or type 2 diabetes, as it is often difficult to distinguish MODY from these two forms. However, diagnosis allows appropriate individualized care, depending on the genetic etiology, and allows prognostication in family members. In this review, we discuss features of the common causes of MODY, as well as the treatment and diagnosis of MODY.

Polyol profile as an early diagnostic and prognostic marker in natural product chemoprevention of hepatocellular carcinoma in diabetic rats

AIM

Diabetes mellitus (DM) is a risk factor for hepatocellular carcinoma (HCC). It directs glucose to sorbitol and fructose in polyol pathway (PP). To pursue contribution of PP in hepatocarcinogenesis.

METHODS

We utilized ascorbic acid (AA) and diallyl sulfide (DAS) in experimental DM and HCC against control. HCC was induced by diethyl nitrosamine (DENA, one intraperitoneal (IP) dose 125 mg/kg), DM, by streptozotocin (STZ, IP dose 65 mg/kg). AA was given as 7.4 g/kg/d, I.P., DAS 200mg/kg/d, orally. All animals were killed after 10 weeks.

RESULTS

DENA elevated serum AFP, erythrocyte sorbitol (ES), neoplastic changes in liver, lowered blood glucose, increased hepatocyte aldose reductase (AR) and sorbitol dehydrogenase (SDH), significantly alleviated by DAS/AA combination. DM elevated ES activating AR, inhibiting SDH, improved by DAS and AA.

CONCLUSION

Co-induction of DM and HCC increased liver tissue lesion, serum AFP, ES, liver AR and SDH. Co-administration of DAS/AA reduced ES, AR without changing SDH. DAS/AA co-therapy lowered ES by depressing AR without affecting SDH, meaning that AR is activated by cancer and DM in different ways. PP is early marker for HCC detection and response to chemoprevention. DAS/AA combination is promising cost effective chemopreventive and anti-diabetic combination.

Species-specific differences in the expression of the HNF1A, HNF1B and HNF4A genes

Background

The HNF1A, HNF1B and HNF4A genes are part of an autoregulatory network in mammalian pancreas, liver, kidney and gut. The layout of this network appears to be similar in rodents and humans, but inactivation of HNF1A, HNF1B or HNF4A genes in animal models cause divergent phenotypes to those seen in man. We hypothesised that some differences may arise from variation in the expression profile of alternatively processed isoforms between species.

Methodology/Principal Findings

We measured the expression of the major isoforms of the HNF1A, HNF1B and HNF4A genes in human and rodent pancreas, islet, liver and kidney by isoform-specific quantitative real-time PCR and compared their expression by the comparative Ct (ΔΔCt) method. We found major changes in the expression profiles of the HNF genes between humans and rodents. The principal difference lies in the expression of the HNF1A gene, which exists as three isoforms in man, but as a single isoform only in rodents. More subtle changes were to the balance of HNF1B and HNF4A isoforms between species; the repressor isoform HNF1B(C) comprised only 6% in human islets compared with 24–26% in rodents (p = 0.006) whereas HNF4A9 comprised 22% of HNF4A expression in human pancreas but only 11% in rodents (p = 0.001).

Conclusions/Significance

The differences we note in the isoform-specific expression of the human and rodent HNF1A, HNF1B and HNF4A genes may impact on the absolute activity of these genes, and therefore on the activity of the pancreatic transcription factor network as a whole. We conclude that alterations to expression of HNF isoforms may underlie some of the phenotypic variation caused by mutations in these genes.

Dominant-negative mutant hepatocyte nuclear factor 1alpha induces diabetes in transgenic-cloned pigs

Pigs have been recognized as an excellent biomedical model for investigating a variety of human health issues. We developed genetically modified pigs that exhibit the apparent symptoms of diabetes. Transgenic cloned pigs carrying a mutant human hepatocyte nuclear factor 1alpha gene, which is known to cause the type 3 form of maturity-onset diabetes of the young, were produced using a combined technology of intracytoplasmic sperm injection-mediated gene transfer and somatic cell nuclear transfer. Although most of the 22 cloned offspring obtained died before weaning, four pigs that lived for 20-196 days were diagnosed as diabetes mellitus with nonfasting blood glucose levels greater than 200 mg/dl. Oral glucose tolerance test on a cloned pig also revealed a significant increase of blood glucose level after glucose loading. Histochemical analysis of pancreas tissue from the cloned pigs showed small and irregularly formed Langerhans Islets, in which poor insulin secretion was detected.

Role of HNF-1α and HNF-1β on insulin, IGF-1 and other potential target genes

Hepatocyte nuclear factor (HNF)-1α and HNF-1β are transcription factors that regulate many target genes in various tissues including liver, pancreas and kidney. Heterozygous mutations in the HNF-1α and HNF-1β genes result in maturity-onset diabetes of the young (MODY)3 and MODY5, respectively. The discovery of these 'hepatocyte nuclear factors' as MODY-responsible genes provided a breakthrough in the field of diabetes. Patients with HNF-1α and HNF-1β mutations, as well as their model mice, show impaired pancreatic β-cell function. The mechanism of impaired β-cell function and the target genes has been intensively investigated by considerable in vitro and in vivo studies. The insulin gene is one of the target genes of HNF-1α and HNF-1β in the β-cells, and may contribute to the diabetes. The IGF-1 gene is also regulated by HNF-1α and HNF-1β, and its decreased expression may contribute to growth failure and impaired β-cell proliferation. Mutations in HNF-1β result in symptoms in multiple organs, including kidney and liver, and several target genes have been reported to be involved in the pathogenesis. HNF-1α and HNF-1β may be one of the master regulators of hepatocyte and islet transcription, and further investigations by microarray and genome-scale analyses are providing information for the better understanding of the complex transcriptional network involving HNF-1α and -1β.

Neonatal diabetes mellitus

An explosion of work over the last decade has produced insight into the multiple hereditary causes of a nonimmunological form of diabetes diagnosed most frequently within the first 6 months of life. These studies are providing increased understanding of genes involved in the entire chain of steps that control glucose homeostasis. Neonatal diabetes is now understood to arise from mutations in genes that play critical roles in the development of the pancreas, of beta-cell apoptosis and insulin processing, as well as the regulation of insulin release. For the basic researcher, this work is providing novel tools to explore fundamental molecular and cellular processes. For the clinician, these studies underscore the need to identify the genetic cause underlying each case. It is increasingly clear that the prognosis, therapeutic approach, and genetic counseling a physician provides must be tailored to a specific gene in order to provide the best medical care.

Na(+) -glucose transporter-2 messenger ribonucleic acid expression in kidney of diabetic rats correlates with glycemic levels: involvement of hepatocyte nuclear factor-1alpha expression and activity

Mutations in Na(+)-glucose transporters (SGLT)-2 and hepatocyte nuclear factor (HNF)-1alpha genes have been related to renal glycosuria and maturity-onset diabetes of the young 3, respectively. However, the expression of these genes have not been investigated in type 1 and type 2 diabetes. Here in kidney of diabetic rats, we tested the hypotheses that SGLT2 mRNA expression is altered; HNF-1alpha is involved in this regulation; and glycemic homeostasis is a related mechanism. The in vivo binding of HNF-1alpha into the SGLT2 promoter region in renal cortex was confirmed by chromatin immunoprecipitation assay. SGLT2 and HNF-1alpha mRNA expression (by Northern and RT-PCR analysis) and HNF-1 binding activity of nuclear proteins (by EMSA) were investigated in diabetic rats and treated or not with insulin or phlorizin (an inhibitor of SGLT2). Results showed that diabetes increases SGLT2 and HNF-1alpha mRNA expression (~50%) and binding of nuclear proteins to a HNF-1 consensus motif (~100%). Six days of insulin or phlorizin treatment restores these parameters to nondiabetic-rat levels. Moreover, both treatments similarly reduced glycemia, despite the differences in plasma insulin and urinary glucose concentrations, highlighting the plasma glucose levels as involved in the observed modulations. This study shows that SGLT2 mRNA expression and HNF-1alpha expression and activity correlate positively in kidney of diabetic rats. It also shows that diabetes-induced changes are reversed by lowering glycemia, independently of insulinemia. Our demonstration that HNF-1alpha binds DNA that encodes SGLT2 supports the hypothesis that HNF-1alpha, as a modulator of SGLT2 expression, may be involved in diabetic kidney disease.

Neonatal cholestatic jaundice as the first symptom of a mutation in the hepatocyte nuclear factor-1beta gene (HNF-1beta)

This report describes the phenotype of a novel de novo heterozygous frameshift mutation in the hepatocyte nuclear factor-1beta gene (HNF-1beta or TCF2) manifest as a neonatal paucity of intrahepatic bile ducts. HNF-1beta mutations should be considered in neonates with cholestatic jaundice associated with renal malformation or diabetes mellitus.

Anomalies of the TCF2 gene are the main cause of fetal bilateral hyperechogenic kidneys

Prenatal discovery of fetal bilateral hyperechogenic kidneys is very stressful for pregnant women and their family, and accurate diagnosis of the cause of the moderate forms of this pathology is very difficult. Hepatocyte nuclear factor-1beta that is encoded by the TCF2 gene is involved in the embryonic development of the kidneys. Sixty-two pregnancies with fetal bilateral hyperechogenic kidneys including 25 fetuses with inaccurate diagnosis were studied. TCF2 gene anomalies were detected in 18 (29%) of these 62 patients, and 15 of these 18 patients presented a complete heterozygous deletion of the TCF2 gene. Family screening revealed de novo TCF2 anomalies in more than half of the patients. TCF2 anomalies were associated with normal amniotic fluid volume and normal-sized kidneys between -2 and +2 SD in all patients except for two sisters. Antenatal cysts were detected in 11 of 18 patients, unilaterally in eight of 11. After birth, cysts appeared during the first year (17 of 18), and in patients with antenatal cysts, the number increased and developed bilaterally with decreased renal growth. In these 18 patients, the GFR decreased with longer follow-up and was lower in patients with solitary functioning dysplastic kidney. Heterozygous deletion of the TCF2 gene is an important cause of fetal hyperechogenic kidneys in this study and showed to be linked with early disease expression. The renal phenotype and the postnatal evolution were extremely variable and need a prospective long-term follow-up. Extrarenal manifestations are frequent in TCF2-linked pathologies. Therefore, prenatal counseling and follow-up should be multidisciplinary.

Contrasting insulin sensitivity of endogenous glucose production rate in subjects with hepatocyte nuclear factor-1beta and -1alpha mutations

Heterozygous mutations in the transcription factors hepatocyte nuclear factor (HNF)-1alpha and -1beta result in MODY (maturity-onset diabetes of the young). Despite structural similarity between HNF-1alpha and -1beta, HNF-1beta mutation carriers have hyperinsulinemia, whereas HNF-1alpha mutation carriers have normal or reduced insulin concentrations. We examined whether HNF-1beta mutation carriers are insulin resistant. The endogenous glucose production rate and rate of glucose uptake were measured with a two-step, low-dose (0.3 mU . kg(-1) . min(-1)) and high-dose (1.5 mU . kg(-1) . min(-1)) hyperinsulinemic-euglycemic clamp, with an infusion of [6,6-(2)H(2)]glucose, in six subjects with HNF-1alpha mutations, six subjects with HNF-1beta mutations, and six control subjects, matched for age, sex, and BMI. Endogenous glucose production rate was not suppressed by low-dose insulin in HNF-1beta subjects but was suppressed by 89% in HNF-1alpha subjects (P = 0.004) and 80% in control subjects (P < 0.001). Insulin-stimulated glucose uptake and suppression of lipolysis were similar in all groups at low- and high-dose insulin. Subjects with HNF-1beta mutations have reduced insulin sensitivity of endogenous glucose production but normal peripheral insulin sensitivity. This is likely to reflect reduced action of HNF-1beta in the liver and possibly the kidney. This may be mediated through regulation by HNF-1beta of the key gluconeogenic enzymes glucose-6-phosphatase or PEPCK.

Renal Phenotypes Related to Hepatocyte Nuclear Factor-1β (TCF2) Mutations in a Pediatric Cohort

The hepatocyte nuclear factor-1beta encoded by the TCF2 gene plays a role for the specific regulation of gene expression in various tissues such as liver, kidney, intestine, and pancreatic islets and is involved in the embryonic development of these organs. TCF2 mutations are known to be responsible for the maturity-onset diabetes of the young type 5 associated with renal manifestations. Several observations have suggested that TCF2 mutations may be involved in restricted renal phenotypes. Eighty children (median age at diagnosis 0.2 yr) with renal cysts, hyperechogenicity, hypoplasia, or single kidneys were studied. Quantitative multiplex PCR amplification of short fluorescence fragments for the search of large genomic rearrangements and sequencing for the detection of point mutations were performed. TCF2 anomalies were detected in one third of patients (25 of 80). The main alteration was the complete deletion of the TCF2 gene detected in 16 patients. Family screening revealed de novo TCF2 anomalies in nine of 17 probands with a high prevalence of deletions (seven of nine). TCF2 anomalies were associated with bilateral renal anomalies (P < 0.001) and bilateral cortical cysts (P < 0.001). However, abnormal renal function, detected in 40% of patients, was independent of the TCF2 genotype. No difference in renal function or severity of renal morphologic lesions was observed between patients with a TCF2 deletion and those with point mutations. In conclusion, TCF2 molecular anomalies are involved in restricted renal phenotype in childhood without alteration of glucose metabolism. These findings have important implications in the diagnosis of patients with renal dysplasia with cysts and their follow-up.

Diagnosis and Management of Maturity-Onset Diabetes of the Young

Maturity-onset diabetes of the young (MODY) is a dominantly inherited form of non-ketotic diabetes mellitus. It results from a primary defect of insulin secretion, and usually develops at childhood, adolescence, or young adulthood. MODY is a heterogeneous disease with regard to genetic, metabolic, and clinical features. All MODY genes have not been identified, but heterozygous mutations in six genes cause the majority of the MODY cases. By far MODY2 (due to mutations of the glucokinase gene) and MODY3 (due to mutations in hepatocyte nuclear factor-1alpha) are the most frequent. As with MODY3, all the other MODY subtypes are associated with mutations in transcription factors. The clinical presentations of the different MODY subtypes differ, particularly in the severity and the course of the insulin secretion defect, the risk of microvascular complications of diabetes, and the defects associated with diabetes. Patients with MODY2 have mild, asymptomatic, and stable hyperglycemia that is present from birth. They rarely develop microvascular disease, and seldom require pharmacologic treatment of hyperglycemia. In patients with MODY3, severe hyperglycemia usually occurs after puberty, and may lead to the diagnosis of type 1 diabetes. Despite the progression of insulin defects, sensitivity to sulfonylureas may be retained in MODY3 patients. Diabetic retinopathy and nephropathy frequently occur in patients with MODY3, making frequent follow-up mandatory. By contrast, other risk factors are not present in patients with MODY and the frequency of cardiovascular disease is not increased. The clinical spectrum of MODY is wider than initially described, and might include multi-organ involvement in addition to diabetes. In patients with MODY5, due to mutations in hepatocyte nuclear factor-1beta, diabetes is associated with pancreatic atrophy, renal morphologic and functional abnormalities, and genital tract and liver test abnormalities. Although MODY is dominantly inherited, penetrance or expression of the disease may vary and a family history of diabetes is not always present. Thus, the diagnosis of MODY should be raised in various clinical circumstances. Molecular diagnosis has important consequences in terms of prognosis, family screening, and therapy.

Genetic and clinical characteristics of maturity-onset diabetes of the young in Chinese patients

In Caucasians, maturity-onset diabetes of the young (MODY) is mostly caused by mutations in the hepatocyte nuclear factor (HNF)-1alpha (MODY3) and glucokinase (MODY2) genes. Most Japanese MODY patients, however, are not linked to known MODY genes. In this study, we examined the genetic and clinical characteristics of Chinese subjects with MODY. The study included 146 unrelated families fulfilling the minimum criteria for MODY: two consecutive generations of type II diabetes with at least one member diagnosed under the age of 25. We screened for mutations in the HNF-4alpha (MODY1), MODY2 and MODY3 genes by direct sequencing. Antibody to glutamic acid decarboxylase (GAD-Ab) was measured in subjects with MODY of unknown cause (MODYX). Insulin resistance index and other clinical data were compared in sex-, age- and duration-matched MODY3 and MODYX patients. In all, 13 families had MODY3 mutations and two had MODY2 mutations. No MODY1 mutation was found. Four of the 12 different MODY3 mutations were newly identified novel mutations (Q243E, A311D, P379R and P488fsdelC). In subjects with MODYX, 3% were GAD-Ab positive and 60% were overweight. Compared to MODY3 patients, MODYX patients had higher body mass index (P<0.02), higher insulin resistance index (P=0.001) and triglyceride level (P<0.02), lower HDL level (P=0.001) and more hypertension (P<0.05), but no significant difference in the prevalence of diabetic complications. In conclusion, MODY3 and MODY2 account for only 9 and 1%, respectively, of Chinese MODY. A majority of Chinese MODY patients are due to defects in unknown genes and appear to be characterized by insulin resistance.