HNF1ß-associated cyst development and electrolyte disturbances are not explained by BAIAP2L2 expression.

Mutations or deletions in transcription factor hepatocyte nuclear factor 1 homeobox ß (HNF1ß) cause renal cysts and/or malformation, maturity-onset diabetes of the young and electrolyte disturbances. Here, we applied a comprehensive bioinformatic approach on ChIP-seq, RNA-seq, and gene expression array studies to identify novel transcriptional targets of HNF1ß explaining the kidney phenotype of HNF1ß patients. We identified BAR/IMD Domain Containing Adaptor Protein 2 Like 2 (BAIAP2L2), as a novel transcriptional target of HNF1ß and validated direct transcriptional activation of the BAIAP2L2 promoter by a reporter luciferase assay. Using mass spectrometry analysis, we show that BAIAP2L2 binds to other members of the I-BAR domain-containing family: BAIAP2 and BAIAP2L1. Subsequently, the role of BAIAP2L2 in maintaining epithelial cell integrity in the kidney was assessed using Baiap2l2 knockout cell and mouse models. Kidney epithelial cells lacking functional BAIAP2L2 displayed normal F-actin distribution at cell-cell contacts and formed polarized three-dimensional spheroids with a lumen. In vivo, Baiap2l2 knockout mice displayed normal kidney and colon tissue morphology and serum and urine electrolyte concentrations were not affected. Altogether, our study is the first to characterize the function of BAIAP2L2 in the kidney in vivo and we report that mice lacking BAIAP2L2 exhibit normal electrolyte homeostasis and tissue morphology under physiological conditions.

Mechanisms of ion transport regulation by HNF1ß in the kidney: beyond transcriptional regulation of channels and transporters.

Hepatocyte nuclear factor 1ß (HNF1ß) is a transcription factor essential for the development and function of the kidney. Mutations in and deletions of HNF1ß cause autosomal dominant tubule interstitial kidney disease (ADTKD) subtype HNF1ß, which is characterized by renal cysts, diabetes, genital tract malformations, and neurodevelopmental disorders. Electrolyte disturbances including hypomagnesemia, hyperuricemia, and hypocalciuria are common in patients with ADTKD-HNF1ß. Traditionally, these electrolyte disturbances have been attributed to HNF1ß-mediated transcriptional regulation of gene networks involved in ion transport in the distal part of the nephron including FXYD2, CASR, KCNJ16, and FXR. In this review, we propose additional mechanisms that may contribute to the electrolyte disturbances observed in ADTKD-HNF1ß patients. Firstly, kidney development is severely affected in Hnf1b-deficient mice. HNF1ß is required for nephron segmentation, and the absence of the transcription factor results in rudimentary nephrons lacking mature proximal tubule, loop of Henle, and distal convoluted tubule cluster. In addition, HNF1ß is proposed to be important for apical-basolateral polarity and tight junction integrity in the kidney. Interestingly, cilia formation is unaffected by Hnf1b defects in several models, despite the HNF1ß-mediated transcriptional regulation of many ciliary genes. To what extent impaired nephron segmentation, apical-basolateral polarity, and cilia function contribute to electrolyte disturbances in HNF1ß patients remains elusive. Systematic phenotyping of Hnf1b mouse models and the development of patient-specific kidney organoid models will be essential to advance future HNF1ß research.

Autosomal dominant tubulointerstitial kidney disease: more than just HNF1ß.

Autosomal dominant tubulointerstitial kidney disease (ADTKD) refers to a group of disorders with a bland urinary sediment, slowly progressive chronic kidney disease (CKD), and autosomal dominant inheritance. Due to advances in genetic diagnosis, ADTKD is becoming increasingly recognized as a cause of CKD in both children and adults. ADTKD-REN presents in childhood with mild hypotension, CKD, hyperkalemia, acidosis, and anemia. ADTKD-UMOD is associated with gout and CKD that may present in adolescence and slowly progresses to kidney failure. HNF1ß mutations often present in childhood with anatomic abnormalities such as multicystic or dysplastic kidneys, as well as CKD and a number of other extra-kidney manifestations. ADTKD-MUC1 is less common in childhood, and progressive CKD is its sole clinical manifestation, usually beginning in the late teenage years. This review describes the pathophysiology, genetics, clinical characteristics, diagnosis, and treatment of the different forms of ADTKD, with an emphasis on diagnosis. We also present data on kidney function in children with ADTKD from the Wake Forest Rare Inherited Kidney Disease Registry.

Retinoic acid-induced expression of Hnf1b and Fzd4 is required for pancreas development in Xenopus laevis.

Retinoic acid (RA) is required for pancreas specification in Xenopus and other vertebrates. However, the gene network that is directly induced by RA signalling in this context remains to be defined. By RNA sequencing of in vitro-generated pancreatic explants, we identified the genes encoding the transcription factor Hnf1ß and the Wnt-receptor Fzd4/Fzd4s as direct RA target genes. Functional analyses of Hnf1b and Fzd4/Fzd4s in programmed pancreatic explants and whole embryos revealed their requirement for pancreatic progenitor formation and differentiation. Thus, Hnf1ß and Fzd4/Fzd4s appear to be involved in pre-patterning events of the embryonic endoderm that allow pancreas formation in Xenopus.

Hepatocyte nuclear factor-1 beta protects endometriotic cells against apoptotic cell death by up-regulating the expression of antiapoptotic genes†.

The overexpression of hepatocyte nuclear factor-1 beta (HNF1ß) in endometriotic lesion has been demonstrated. However, the role of HNF1ß in endometriosis remains largely unknown. Human endometriotic 12Z cells showed higher level of HNF1ß when compared with normal endometrial HES cells. In human endometriotic 12Z cells, HNF1ß knockdown increased susceptibility to apoptotic cell death by oxidative stress, while HNF1ß overexpression suppressed apoptosis. In addition, HNF1ß knockdown and overexpression significantly decreased and increased, respectively, the expression of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-dependent antiapoptotic genes. Knockdown of the antiapoptotic genes significantly reduced the HNF1ß-induced resistance against oxidative stress in 12Z cells. Furthermore, HNF1ß regulated the transcriptional activity of NF-κB, and an NF-κB inhibitor suppressed the HNF1ß-enhanced NF-κB-dependent antiapoptotic gene expression and the resistance of the 12Z cells against cell death. Taken together, these data suggest that HNF1ß overexpression may protect endometriotic cells against oxidative damage by augmenting antiapoptotic gene expression.

Tumor-suppressive activity of Hnf1ß in Wilms' tumor.

Hepatocyte nuclear factor 1ß (HNF1ß) is a transcription factor belonging to the HNF-1 family and has been implicated in a number of cancers, but its role in Wilms' tumor (nephroblastoma) has not been addressed. Here, we compared its expression between Wilms' tumor patient kidney tissue and adjacent tissue based on the Oncomine database ( www.oncomine.com ). Cell proliferation, apoptosis, migration, and HNF1ß expression level were analyzed in Wilms' tumor-derived G401 cells. Using a variety of mouse tissues (lung, heart, kidney, etc.), we found that HNF1ß is the highest expression in the kidneys. Oncomine analysis further demonstrated that HNF1ß has a lower expression in Wilms' tumor tissue than in paracancerous tissues. Overexpression of HNF1ß decreased cell proliferation and migration, but promoted cell apoptosis. Knockdown of HNF1ß produced the opposite results. These results indicated that HNF1ß may play important roles in kidney development and function, and its activation may negatively regulate Wilms' tumor progression.

Case Report: Identification of an HNF1B p.Arg527Gln mutation in a Maltese patient with atypical early onset diabetes and diabetic nephropathy.

BACKGROUND: The diagnosis of atypical non-autoimmune forms of diabetes mellitus, such as maturity onset diabetes of the young (MODY) presents several challenges, in view of the extensive clinical and genetic heterogeneity of the disease. In this report we describe a case of atypical non autoimmune diabetes associated with a damaging HNF1ß mutation. This is distinguished by a number of uncharacteristic clinical features, including early-onset obesity, the absence of renal cysts and diabetic nephropathy. HNF1ß-MODY (MODY5) is an uncommon form of monogenic diabetes that is often complicated by a wide array of congenital morphological anomalies of the urinary tract, including renal cysts. This report expands on the clinical phenotypes that have been described in the context of HNF1ß mutations, and is relevant as only isolated cases of diabetic nephropathy in the setting of MODY5 have been reported. CASE PRESENTATION: An obese Maltese female with non-autoimmune diabetes, microalbuminuria, glomerular hyperfiltration, fatty liver and no renal cysts was studied by whole exome sequencing to investigate potential genes responsible for the proband's phenotype. A rare missense mutation at a highly conserved site in exon 8 of HNF1ß was identified (c.1580G > A, NM_000458.3, p.Arg527Gln), with multiple in-silico predictions consistent with pathogenicity. This mutation has not been previously characterised. Additionally, several common susceptibility variants associated with early-onset obesity, polygenic type 2 diabetes and nephropathy were identified in the proband that could impose additional effects on the phenotype, its severity or its clinical course. CONCLUSION: This report highlights several atypical features in a proband with atypical diabetes associated with an HNF1ß missense mutation. It also reinforces the concept that monogenic causes of diabetes could be significant contributors to disease burden in obese individuals with atypical diabetes.

Loss of transcriptional activation of the potassium channel Kir5.1 by HNF1ß drives autosomal dominant tubulointerstitial kidney disease.

Hepatocyte nuclear factor 1 homeobox B (HNF1ß) is an essential transcription factor for the development and functioning of the kidney. Mutations in HNF1ß 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 HNF1ß 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 HNF1ß binding sites on a genome-wide scale. In total 7,421 HNF1ß-binding sites were identified, including several genes involved in electrolyte transport and diabetes. A highly specific and conserved HNF1ß 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 HNF1ß was present. Expression of the Hnf1ß p.Lys156Glu mutant, previously identified in a patient with autosomal dominant tubulointerstitial kidney disease, did not activate Kcnj16 expression. Knockdown of Hnf1ß 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 HNF1ß renal knockout mouse which exhibited downregulation of Kcnj16, Kcnj10 and Slc12a3 transcripts in the kidney by 78%, 83% and 76%, respectively, compared to HNF1ß wild-type mice. Thus, HNF1ß is a transcriptional activator of Kcnj16. Hence, patients with HNF1ß mutations may have reduced Kir5.1 activity in the kidney, resulting in hypokalemia and hypomagnesemia.

Hepatocyte nuclear factor-1ß (HNF-1ß) promotes glucose uptake and glycolytic activity in ovarian clear cell carcinoma.

Ovarian clear cell carcinoma (OCCC) is a morphologically and biologically distinct subtype of ovarian carcinomas that often arises in ovarian endometriosis. We previously reported that a unique carcinogenic environment, especially iron-induced oxidative stress in endometriotic cysts may promote development of OCCC. We also identified a gene expression profile characteristic of OCCC (the "OCCC signature"). This 320-gene OCCC signature is enriched in genes associated with stress response and sugar metabolism. However, the biological implication of this profile is unclear. In this study, we have focused on the biological role of the HNF-1ß gene within the OCCC signature, which was previously shown to be overexpressed in OCCC. Suppression of HNF-1ß in the HNF-1ß-overexpressing human ovarian cancer cell line RMG2 using short hairpin RNA resulted in a significant increase in proliferation. It also facilitated glucose uptake, glycolytic activity, and lactate secretion along with increased expression of the glucose transporter-1 (GLUT-1) gene and several key enzymes in the glycolytic process. Conversely, forced expression of HNF-1ß in the serous ovarian cancer cell line, Hey, resulted in slowed cellular growth and repressed glycolytic activity. These data suggest that HNF-1ß represses cell growth, and at the same time, it promotes aerobic glycolysis which is known as the "Warburg effect." As the Warburg effect is regarded as a characteristic metabolic process in cancer which may contribute to cell survival under hypoxic conditions or in a stressful environment, overexpression of HNF-1ß may play an inevitable role in the occurrence of OCCC in stressful environment.

Criteria for HNF1B analysis in patients with congenital abnormalities of kidney and urinary tract.

BACKGROUND: Congenital anomalies of kidneys and urinary tract (CAKUT) are the most predominant developmental disorders comprising ∼20-30% of all anomalies identified in the prenatal period. Mutations in hepatocyte nuclear factor 1-beta (HNF-1ß) involved in the development of kidneys, liver, pancreas and urogenital tract are currently the most frequent monogenetic cause of CAKUT found in 10-30% of patients depending on screening policy and study design. We aimed to validate criteria for analysis of HNF1B in a prospective cohort of paediatric and adult CAKUT patients. METHODS: We included CAKUT patients diagnosed in our paediatric and adult nephrology departments from January 2010 until April 2013 based on predefined screening criteria. Subjects presenting with at least one major renal criterion or one minor renal criterion combined with one or more extra-renal criteria in the personal history or a familial history of renal or extra-renal manifestations were considered eligible. RESULTS: We prospectively screened 205 patients and detected HNF1B mutations in 10% [n = 20, 12 children, median age 4.2 (range 0-13.1) years and 8 adults, median age 34.8 (range 16.6-62) years]. We observed that bilateral renal anomaly, renal cysts from unknown origin, a combination of two major renal anomalies and hypomagnesaemia were predictive for finding HNF1B mutations (P < 0.001; P < 0.001; P = 0.004; P = 0.008, respectively). CONCLUSIONS: We demonstrated that HNF1B mutations are responsible for ∼10% of CAKUT cases, both in children and in adults. Based on our results we propose adapted criteria for HNF1B analysis to reduce the screening costs without missing affected patients. These criteria should be reaffirmed in a larger validation cohort.

The transcription factor HNF1α induces expression of angiotensin-converting enzyme 2 (ACE2) in pancreatic islets from evolutionarily conserved promoter motifs.

Pancreatic angiotensin-converting enzyme 2 (ACE2) has previously been shown to be critical for maintaining glycemia and ß-cell function. Efforts to maintain or increase ACE2 expression in pancreatic ß-cells might therefore have therapeutic potential for treating diabetes. In our study, we investigated the transcriptional role of hepatocyte nuclear factor 1α (HNF1α) and hepatocyte nuclear factor 1ß (HNF1ß) in induction of ACE2 expression in insulin-secreting cells. A deficient allele of HNF1α or HNF1ß causes maturity-onset diabetes of the young (MODY) types 3 and 5, respectively, in humans. We found that ACE2 is primarily transcribed from the proximal part of the ACE2 promoter in the pancreas. In the proximal part of the human ACE2 promoter, we further identified three functional HNF1 binding sites, as they have binding affinity for HNF1α and HNF1ß and are required for induction of promoter activity by HNF1ß in insulinoma cells. These three sites are well-conserved among mammalian species. Both HNF1α and HNF1ß induce expression of ACE2 mRNA and lead to elevated levels of ACE2 protein and ACE2 enzymatic activity in insulinoma cells. Furthermore, HNF1α dose-dependently increases ACE2 expression in primary pancreatic islet cells. We conclude that HNF1α can induce the expression of ACE2 in pancreatic islet cells via evolutionarily conserved HNF1 binding sites in the ACE2 promoter. Potential therapeutics aimed at counteracting functional HNF1α depletion in diabetes and MODY3 will thus have ACE2 induction in pancreatic islets as a likely beneficial effect.

1H, 13C and 15N backbone resonance assignments of hepatocyte nuclear factor-1-beta (HNF1ß) POUS and POUHD.

Hepatocyte nuclear factor 1ß (HNF1ß) is a transcription factor that plays a key role in the development and function of the liver, pancreas, and kidney. HNF1ß plays a key role in early vertebrate development and the morphogenesis of these organs. In humans, heterozygous mutations in the HNF1B gene can result in organ dysplasia, making it the most common cause of developmental renal diseases, including renal cysts, renal malformations, and familial hypoplastic glomerular cystic kidney disease. Pathogenic variants in the HNF1B gene are known to cause various diseases, including maturity-onset diabetes of the young and developmental renal diseases. This study presents the backbone resonance assignments of HNF1ß POUS and POUHD domains, which are highly conserved domains required for the recognition of double-stranded DNA. Our data will be useful for NMR studies to verify the altered structures and functions of mutant HNF1B proteins that can induce developmental renal diseases, including renal cysts, renal malformations, and familial hypoplastic glomerular cystic kidney disease. This study will provide the structural basis for future studies to elucidate the molecular mechanisms underlying how mutations in HNF1ß cause diseases.

Late-onset Cholestasis with Paucity of Portal Area Secondary to HNF1ß Deficiency in Adulthood: A Case Report.

Hepatocyte nuclear factor 1ß (HNF1ß) 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 HNF1ß 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 HNF1ß defect could induce late-onset cholestasis with paucity of the portal area in adulthood.

Diagnostic accuracy of HNF1ß, Napsin A and P504S/Alpha-Methylacyl-CoA Racemase (AMACR) as markers of endometrial clear cell carcinoma.

Endometrial clear cell carcinoma (CCC) shows morphological overlap with endometrioid and serous carcinoma. We aimed to assess the accuracy of immunohistochemical diagnostic markers of CCC, i.e. HNF1ß, Napsin A and P504S/Alpha-Methylacyl-CoA Racemase (AMACR). A systematic review and meta-analysis was conducted by searching 4 electronic databases from their inception to April 2022 for all studies assessing HNF1ß, Napsin A and/or AMACR in endometrial CCC vs endometrioid/serous carcinomas. Diagnostic accuracy was assessed as sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-), diagnostic odds ratio (DOR) and area under the curve (AUC) on sROC curves. Eleven studies were included. HNF1ß positivity (any expression) showed sensitivity= 0.78; specificity= 0.81; LR+ =2.46; LR-= 0.38; DOR= 5.96; AUC= 0.79. Diffuse HNF1ß expression showed sensitivity= 0.53; specificity= 0.95; LR+ =9.68; LR-= 0.51; DOR= 18.02; AUC= 0.40. Napsin A positivity (any expression) showed sensitivity= 0.76; specificity= 0.97; LR+ =18.79; LR-= 0.27; DOR= 73.31; AUC= 0.81. Diffuse Napsin A expression showed sensitivity= 0.52; specificity= 0.99; LR+ =14.50; LR-= 0.55; DOR= 24.93; AUC= 0.98. AMACR positivity (any expression) showed sensitivity= 0.76; specificity= 0.86; LR+ =4.86; LR-= 0.30; DOR= 13.56; AUC was not assessable due to the presence of only 2 studies. In conclusion, HNF1ß, Napsin A and AMACR show moderate accuracy in identifying endometrial CCC. Considering only a diffuse expression of these markers as positive leads to high specificity but low sensitivity. In particular, Napsin A appears as the most specific marker of endometrial CCC.

An HNF1α truncation associated with maturity-onset diabetes of the young impairs pancreatic progenitor differentiation by antagonizing HNF1ß function.

The HNF1αp291fsinsC truncation is the most common mutation associated with maturity-onset diabetes of the young 3 (MODY3). Although shown to impair HNF1α signaling, the mechanism by which HNF1αp291fsinsC causes MODY3 is not fully understood. Here we use MODY3 patient and CRISPR/Cas9-engineered human induced pluripotent stem cells (hiPSCs) grown as 3D organoids to investigate how HNF1αp291fsinsC affects hiPSC differentiation during pancreatic development. HNF1αp291fsinsC hiPSCs shows reduced pancreatic progenitor and ß cell differentiation. Mechanistically, HNF1αp291fsinsC interacts with HNF1ß and inhibits its function, and disrupting this interaction partially rescues HNF1ß-dependent transcription. HNF1ß overexpression in the HNF1αp291fsinsC patient organoid line increases PDX1+ progenitors, while HNF1ß overexpression in the HNF1αp291fsinsC patient iPSC line partially rescues ß cell differentiation. Our study highlights the capability of pancreas progenitor-derived organoids to model disease in vitro. Additionally, it uncovers an HNF1ß-mediated mechanism linked to HNF1α truncation that affects progenitor differentiation and could explain the clinical heterogeneity observed in MODY3 patients.

Diabetes Mellitus With Renal and Müllerian Anomalies.

OBJECTIVE: Maturity-onset diabetes of the young (MODY) type 5 is caused by an autosomal dominant mutation in the HNF1B gene. Our objective was to report a case of a young girl with bicornuate uterus and recurrent renal stones with diabetes mellitus (DM) without a family history that was diagnosed to be MODY 5. CASE REPORT: A 12-year-old girl presented with recurrent renal stones that were managed with lithotripsy and double-J stenting at various time points. At the age of 14 years, she was found to have a bicornuate uterus with an absent cervix and vagina. She was diagnosed with DM at the age of 16 years without a preceding history of osmotic symptoms or steatorrhea. Although there was no family history of young-onset diabetes, given her long-standing history of müllerian abnormalities, renal cysts, and pancreatic hypotrophy, she was evaluated for MODY. Using the next-generation sequencing, she was found to be positive for a reported HNF1B gene pathogenic mutation c.494G>A (p.Arg165His), confirming a diagnosis of MODY 5. DISCUSSION: There is a significant overlap in clinical criteria for type 2 DM and MODY in the Asian Indian population. The HNF1B gene mutation is difficult to diagnose as none of the clinical manifestations are pathognomonic and many lack a family history of DM. Diagnostic algorithms with specific clinical and biochemical criteria along with pancreatic imaging can help in case detection and direct toward particular genetic mutation analysis. CONCLUSION: We suggest that genetic testing be offered to patients with otherwise unexplained DM and such genitourinary anomalies.

The Expression of Transcription Factors in Fetal Lamb Kidney.

(1) Background: Renal development involves frequent expression and loss of transcription factors, resulting in the activation of genes. Wilms' tumor 1 (WT1), hepatocyte nuclear factor-1-beta (HNF1ß), and paired box genes 2 and 8 (Pax2 and Pax8) play an important role in renal development. With this in vivo study, we examined the period and location of expression of these factors in renal development. (2) Methods: Fetal lamb kidneys (50 days from gestation to term) and adult ewe kidneys were evaluated by hematoxylin and eosin staining. Serial sections were subjected to immunohistochemistry for WT1, HNF1ß, Pax2, and Pax8. (3) Results: Pax2, Pax8, and HNF1ß expression was observed in the ureteric bud and collecting duct epithelial cells. We observed expression of WT1 alone in metanephric mesenchymal cells, glomerular epithelial cells, and interstitial cells in the medullary rays and Pax8 and HNF1ß expression in tubular epithelial cells. WT1 was highly expressed in cells more proximal to the medulla in renal vesicles and in C- and S-shaped bodies. Pax2 was expressed in the middle and peripheral regions, and HNF1ß in cells in the region in the middle of these. (4) Conclusions: WT1 is involved in nephron development. Pax2, Pax8, and HNF1ß are involved in nephron maturation and the formation of peripheral collecting ducts from the Wolffian duct.

miR-194 regulates the proliferation and migration via targeting Hnf1ß in mouse metanephric mesenchyme cells.

Hepatocyte nuclear factor-1ß (Hnf1ß) is associated with early embryogenesis failure, renal cysts, and/or diabetes. However, factors regulating Hnf1ß expression in metanephric mesenchyme cells remain poorly understood. Here, we analyzed the modulation relationship of Hnf1ß and miR-194 in mouse metanephric mesenchyme (MM) cells. Bioinformatics analysis, luciferase assay and semi-quantitative real-time (qPCR), western blotting, 5-ethynyl-2'-deoxyuridine cell proliferation assay, wound healing assay, and flow cytometry were employed to detect the function of miR-194 by targeting on Hnf1ß in mouse MM cells. Bioinformatic prediction revealed one conserved binding site (CAGTATT) of miR-194 on Hnf1ß 3'-UTR and luciferase reporter assay suggested that this is an effective target site of miR-194, and mutating CAGTATT with CGTACTT had no effects on luciferase activity compared with control. Overexpression of miR-194 decreased Hnf1ß mRNA and protein level in mouse MM cells. In addition, miR-194-decreased cell proliferation and miR-194-promoted cell apoptosis and migration were reversed by overexpression of Hnf1ß coding region. In addition, Hnf1ß-upregulated genes were decreased in miR-194 overexpression cells and rescued in miR-194 and Hnf1ß CDS region co-overexpression cells. Our findings explored one new regulator of Hnf1ß and revealed the function of their regulation in cell proliferation, migration, and apoptosis in mouse metanephric mesenchyme cells. For strict regulation of Hnf1ß in kidney development, these findings provide theoretical guidance for kidney development study and kidney disease therapy.

Not only Alagille syndrome. Syndromic paucity of interlobular bile ducts secondary to HNF1ß 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 HFN1ß 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 HFN1ß 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 HNF1ß 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 HNF1ß deficiency should also be ruled out, taking into consideration HNF1ß 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.