NKX2-2 Mutation Causes Congenital Diabetes and Infantile Obesity With Paradoxical Glucose-Induced Ghrelin Secretion

2020 ◽  
Vol 105 (11) ◽  
Author(s):  
Adi Auerbach ◽  
Amitay Cohen ◽  
Noa Ofek Shlomai ◽  
Ariella Weinberg-Shukron ◽  
Suleyman Gulsuner ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Developmental Delay ◽  
Cell Fate ◽  
Severe Obesity ◽  
Very Low Birth Weight ◽  
Islet Cells ◽  
Neonatal Diabetes ◽  
Oral Glucose ◽  
Β Cell ◽  
Ghrelin Secretion

Abstract Context NKX2-2 is a crucial transcription factor that enables specific β-cell gene expression. Nkx2-2(–/–) mice manifest with severe neonatal diabetes and changes in β-cell progenitor fate into ghrelin-producing cells. In humans, recessive NKX2-2 gene mutations have been recently reported as a novel etiology for neonatal diabetes, with only 3 cases known worldwide. This study describes the genetic analysis, distinctive clinical features, the therapeutic challenges, and the unique pathophysiology causing neonatal diabetes in human NKX2-2 dysfunction. Case Description An infant with very low birth weight (VLBW) and severe neonatal diabetes (NDM) presented with severe obesity and developmental delay already at age 1 year. The challenge of achieving glycemic control in a VLBW infant was unexpectedly met by a regimen of 3 daily doses of long-acting insulin analogues. Sanger sequencing of known NDM genes (such as ABCC8 and EIF2AK3) was followed by whole-exome sequencing that revealed homozygosity of a pathogenic frameshift variant, c.356delG, p.P119fs64*, in the islet cells transcription factor, NKX2-2. To elucidate the cause for the severe obesity, an oral glucose tolerance test was conducted at age 3.5 years and revealed undetectable C-peptide levels with a paradoxically unexpected 30% increase in ghrelin levels. Conclusion Recessive NKX2-2 loss of function causes severe NDM associated with VLBW, childhood obesity, and developmental delay. The severe obesity phenotype is associated with postprandial paradoxical ghrelin secretion, which may be related to human β-cell fate change to ghrelin-secreting cells, recapitulating the finding in Nkx2-2(–/–) mice islet cells.

scholarly journals NEUROD1 Is Required for the Early α and β Endocrine Differentiation in the Pancreas

2021 ◽  
Vol 22 (13) ◽  
pp. 6713
Author(s):  
Romana Bohuslavova ◽  
Ondrej Smolik ◽  
Jessica Malfatti ◽  
Zuzana Berkova ◽  
Zaneta Novakova ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Cell Fate ◽  
Cell Mass ◽  
Neonatal Diabetes ◽  
Diabetes Research ◽  
Pancreas Development ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Islet Cell ◽  
Endocrine Differentiation

Diabetes is a metabolic disease that involves the death or dysfunction of the insulin-secreting β cells in the pancreas. Consequently, most diabetes research is aimed at understanding the molecular and cellular bases of pancreatic development, islet formation, β-cell survival, and insulin secretion. Complex interactions of signaling pathways and transcription factor networks regulate the specification, growth, and differentiation of cell types in the developing pancreas. Many of the same regulators continue to modulate gene expression and cell fate of the adult pancreas. The transcription factor NEUROD1 is essential for the maturation of β cells and the expansion of the pancreatic islet cell mass. Mutations of the Neurod1 gene cause diabetes in humans and mice. However, the different aspects of the requirement of NEUROD1 for pancreas development are not fully understood. In this study, we investigated the role of NEUROD1 during the primary and secondary transitions of mouse pancreas development. We determined that the elimination of Neurod1 impairs the expression of key transcription factors for α- and β-cell differentiation, β-cell proliferation, insulin production, and islets of Langerhans formation. These findings demonstrate that the Neurod1 deletion altered the properties of α and β endocrine cells, resulting in severe neonatal diabetes, and thus, NEUROD1 is required for proper activation of the transcriptional network and differentiation of functional α and β cells.

scholarly journals The islet-expressed Lhx1 transcription factor interacts with Islet-1 and contributes to glucose homeostasis

2019 ◽  
Vol 316 (3) ◽  
pp. E397-E409
Author(s):  
Maigen Bethea ◽  
Yanping Liu ◽  
Alexa K. Wade ◽  
Rachel Mullen ◽  
Rajesh Gupta ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Glucose Homeostasis ◽  
Target Genes ◽  
Fasting Blood Glucose ◽  
Oral Glucose ◽  
Β Cell ◽  
Knockout Mouse Model ◽  
Glucose Levels ◽  
Cell Extracts ◽  
Islet 1

The LIM-homeodomain (LIM-HD) transcription factor Islet-1 (Isl1) interacts with the LIM domain-binding protein 1 (Ldb1) coregulator to control expression of key pancreatic β-cell genes. However, Ldb1 also has Isl1-independent effects, supporting that another LIM-HD factor interacts with Ldb1 to impact β-cell development and/or function. LIM homeobox 1 (Lhx1) is an Isl1-related LIM-HD transcription factor that appears to be expressed in the developing mouse pancreas and in adult islets. However, roles for this factor in the pancreas are unknown. This study aimed to determine Lhx1 interactions and elucidate gene regulatory and physiological roles in the pancreas. Co-immunoprecipitation using β-cell extracts demonstrated an interaction between Lhx1 and Isl1, and thus we hypothesized that Lhx1 and Isl1 regulate similar target genes. To test this, we employed siRNA-mediated Lhx1 knockdown in β-cell lines and discovered reduced Glp1R mRNA. Chromatin immunoprecipitation revealed Lhx1 occupancy at a domain also known to be occupied by Isl1 and Ldb1. Through development of a pancreas-wide knockout mouse model ( Lhx1∆Panc), we demonstrate that aged Lhx1∆Panc mice have elevated fasting blood glucose levels, altered intraperitoneal and oral glucose tolerance, and significantly upregulated glucagon, somatostatin, pancreatic polypeptide, MafB, and Arx islet mRNAs. Additionally, Lhx1∆Panc mice exhibit significantly reduced Glp1R, an mRNA encoding the insulinotropic receptor for glucagon-like peptide 1 along with a concomitant dampened Glp1 response and mild glucose intolerance in mice challenged with oral glucose. These data are the first to reveal that the Lhx1 transcription factor contributes to normal glucose homeostasis and Glp1 responses.

scholarly journals β-cell SENP1 facilitates responsiveness to incretins and limits oral glucose intolerance in high fat fed mice

2020 ◽  
Author(s):  
Haopeng Lin ◽  
Nancy Smith ◽  
Aliya F Spigelman ◽  
Kunimasa Suzuki ◽  
Mourad Ferdaoussi ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Intolerance ◽  
Knockout Mice ◽  
Islet Cells ◽  
Metabolic Stress ◽  
Glucagon Secretion ◽  
Oral Glucose ◽  
High Fat ◽  
Β Cell ◽  
Islet Mass

AbstractSUMOylation reduces oxidative stress and preserves islet mass; but this happens at the expense of robust insulin secretion. To investigate a role for the deSUMOylating enzyme sentrin-specific protease 1 (SENP1) in glycemia following metabolic stress, we put pancreas/gut-specific SENP1 knockout mice (pSENP1-KO) on an 8-10-week high fat diet (HFD). Male pSENP1-KO mice were more glucose intolerant following HFD than littermate controls, but this was only obvious in response to oral glucose, and a similar but milder phenotype was observed in females. Plasma incretin responses were identical, and glucose-dependent insulinotropic polypeptide (GIP) was equally upregulated after HFD, in pSENP1-KO and - WT littermates. Islet mass was not different, but insulin secretion and β-cell exocytotic responses to Exendin4 (Ex4) and GIP were impaired in islets lacking SENP1. Glucagon secretion from pSENP1-KO islets was also reduced, consistent with the expected SENP1 knockout in all islet cells, so we generated β-cell–specific SENP1 knockout mice (βSENP1-KO). These phenocopied the pSENP1-KO mice with selective impairment in oral glucose tolerance following HFD, preserved islet mass expansion, and impaired β-cell exocytosis and insulin secretion to Ex4 and GIP. Thus, β-cell SENP1 limits glucose intolerance following HFD by ensuring a robust facilitation of insulin secretion by incretins such as GIP.

scholarly journals GLIS3: A Critical Transcription Factor in Islet β-Cell Generation

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3471
Author(s):  
David W. Scoville ◽  
Anton M. Jetten
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Current Knowledge ◽  
Neonatal Diabetes ◽  
Cell Development ◽  
Nucleotide Polymorphisms ◽  
Β Cell ◽  
Pancreatic Islet Biology

Understanding of pancreatic islet biology has greatly increased over the past few decades based in part on an increased understanding of the transcription factors that guide this process. One such transcription factor that has been increasingly tied to both β-cell development and the development of diabetes in humans is GLIS3. Genetic deletion of GLIS3 in mice and humans induces neonatal diabetes, while single nucleotide polymorphisms (SNPs) in GLIS3 have been associated with both Type 1 and Type 2 diabetes. As a significant progress has been made in understanding some of GLIS3’s roles in pancreas development and diabetes, we sought to compare current knowledge on GLIS3 within the pancreas to that of other islet enriched transcription factors. While GLIS3 appears to regulate similar genes and pathways to other transcription factors, its unique roles in β-cell development and maturation make it a key target for future studies and therapy.

scholarly journals The EGL-13 SOX Domain Transcription Factor Affects the Uterine Cell Lineages in Caenorhabditis elegans

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1623-1628
Author(s):  
Hediye Nese Cinar ◽  
Keri L Richards ◽  
Kavita S Oommen ◽  
Anna P Newman
Keyword(s):  
Transcription Factor ◽  
Cell Division ◽  
Caenorhabditis Elegans ◽  
Cell Fate ◽  
Cell Lineages

Abstract We isolated egl-13 mutants in which the cells of the Caenorhabditis elegans uterus initially appeared to develop normally but then underwent an extra round of cell division. The data suggest that egl-13 is required for maintenance of the cell fate.

scholarly journals Compromised Function of the Pancreatic Transcription Factor PDX1 in a Lineage of Desert Rodents

2021 ◽  
Author(s):  
Yichen Dai ◽  
Sonia Trigueros ◽  
Peter W. H. Holland
Keyword(s):  
Transcription Factor ◽  
Gene Conversion ◽  
Cell Function ◽  
Protein A ◽  
Gene Promoter ◽  
Homeodomain Protein ◽  
Β Cell ◽  
Desert Rodents ◽  
Biased Gene Conversion ◽  
Β Cell Function

AbstractGerbils are a subfamily of rodents living in arid regions of Asia and Africa. Recent studies have shown that several gerbil species have unusual amino acid changes in the PDX1 protein, a homeodomain transcription factor essential for pancreatic development and β-cell function. These changes were linked to strong GC-bias in the genome that may be caused by GC-biased gene conversion, and it has been hypothesized that this caused accumulation of deleterious changes. Here we use two approaches to examine if the unusual changes are adaptive or deleterious. First, we compare PDX1 protein sequences between 38 rodents to test for association with habitat. We show the PDX1 homeodomain is almost totally conserved in rodents, apart from gerbils, regardless of habitat. Second, we use ectopic gene overexpression and gene editing in cell culture to compare functional properties of PDX1 proteins. We show that the divergent gerbil PDX1 protein inefficiently binds an insulin gene promoter and ineffectively regulates insulin expression in response to high glucose in rat cells. The protein has, however, retained the ability to regulate some other β-cell genes. We suggest that during the evolution of gerbils, the selection-blind process of biased gene conversion pushed fixation of mutations adversely affecting function of a normally conserved homeodomain protein. We argue these changes were not entirely adaptive and may be associated with metabolic disorders in gerbil species on high carbohydrate diets. This unusual pattern of molecular evolution could have had a constraining effect on habitat and diet choice in the gerbil lineage.

scholarly journals Linking metabolic dysfunction with cardiovascular diseases: Brn-3b/POU4F2 transcription factor in cardiometabolic tissues in health and disease

2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Vishwanie S. Budhram-Mahadeo ◽  
Matthew R. Solomons ◽  
Eeshan A. O. Mahadeo-Heads
Keyword(s):  
Transcription Factor ◽  
Cardiovascular Diseases ◽  
Cell Fate ◽  
Target Genes ◽  
Cardiovascular Responses ◽  
Normal Function ◽  
Valuable Insight ◽  
Metabolic Dysfunction ◽  
Pathological Changes ◽  
Cardiac Responses

AbstractMetabolic and cardiovascular diseases are highly prevalent and chronic conditions that are closely linked by complex molecular and pathological changes. Such adverse effects often arise from changes in the expression of genes that control essential cellular functions, but the factors that drive such effects are not fully understood. Since tissue-specific transcription factors control the expression of multiple genes, which affect cell fate under different conditions, then identifying such regulators can provide valuable insight into the molecular basis of such diseases. This review explores emerging evidence that supports novel and important roles for the POU4F2/Brn-3b transcription factor (TF) in controlling cellular genes that regulate cardiometabolic function. Brn-3b is expressed in insulin-responsive metabolic tissues (e.g. skeletal muscle and adipose tissue) and is important for normal function because constitutive Brn-3b-knockout (KO) mice develop profound metabolic dysfunction (hyperglycaemia; insulin resistance). Brn-3b is highly expressed in the developing hearts, with lower levels in adult hearts. However, Brn-3b is re-expressed in adult cardiomyocytes following haemodynamic stress or injury and is necessary for adaptive cardiac responses, particularly in male hearts, because male Brn-3b KO mice develop adverse remodelling and reduced cardiac function. As a TF, Brn-3b regulates the expression of multiple target genes, including GLUT4, GSK3β, sonic hedgehog (SHH), cyclin D1 and CDK4, which have known functions in controlling metabolic processes but also participate in cardiac responses to stress or injury. Therefore, loss of Brn-3b and the resultant alterations in the expression of such genes could potentially provide the link between metabolic dysfunctions with adverse cardiovascular responses, which is seen in Brn-3b KO mutants. Since the loss of Brn-3b is associated with obesity, type II diabetes (T2DM) and altered cardiac responses to stress, this regulator may provide a new and important link for understanding how pathological changes arise in such endemic diseases.

scholarly journals Histone demethylase JMJD2B/KDM4B regulates transcriptional program via distinctive epigenetic targets and protein interactors for the maintenance of trophoblast stem cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kylie Hin-Man Mak ◽  
Yuk Man Lam ◽  
Ray Kit Ng
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Cell Fate ◽  
Histone Demethylase ◽  
Gene Promoters ◽  
Transcriptional Program ◽  
Binding Motifs ◽  
Trophoblast Stem Cells ◽  
Trophoblast Stem ◽  
Trophoblast Stem Cell

AbstractTrophoblast stem cell (TSC) is crucial to the formation of placenta in mammals. Histone demethylase JMJD2 (also known as KDM4) family proteins have been previously shown to support self-renewal and differentiation of stem cells. However, their roles in the context of the trophoblast lineage remain unclear. Here, we find that knockdown of Jmjd2b resulted in differentiation of TSCs, suggesting an indispensable role of JMJD2B/KDM4B in maintaining the stemness. Through the integration of transcriptome and ChIP-seq profiling data, we show that JMJD2B is associated with a loss of H3K36me3 in a subset of embryonic lineage genes which are marked by H3K9me3 for stable repression. By characterizing the JMJD2B binding motifs and other transcription factor binding datasets, we discover that JMJD2B forms a protein complex with AP-2 family transcription factor TFAP2C and histone demethylase LSD1. The JMJD2B–TFAP2C–LSD1 complex predominantly occupies active gene promoters, whereas the TFAP2C–LSD1 complex is located at putative enhancers, suggesting that these proteins mediate enhancer–promoter interaction for gene regulation. We conclude that JMJD2B is vital to the TSC transcriptional program and safeguards the trophoblast cell fate via distinctive protein interactors and epigenetic targets.

Full The Relationship between Continuous Glucose Monitoring and OGTT in Youth and Young Adults with Cystic Fibrosis

2021 ◽  
Author(s):  
Christine L Chan ◽  
Laura Pyle ◽  
Tim Vigers ◽  
Philip S Zeitler ◽  
Kristen J Nadeau
Keyword(s):  
Cystic Fibrosis ◽  
Continuous Glucose Monitoring ◽  
Cell Function ◽  
Glucose Monitoring ◽  
Oral Glucose ◽  
Β Cell ◽  
Oral Glucose Tolerance Testing ◽  
C Peptide ◽  
Β Cell Function ◽  
The Relationship

Abstract Context Early glucose abnormalities in people with CF (PwCF) are commonly detected by continuous glucose monitoring (CGM). Relationships between these CGM abnormalities and oral glucose tolerance testing (OGTT) in PwCF have not been fully characterized. Objective(s) 1) To determine the relationship between CGM and common OGTT-derived estimates of β-cell function, including C-peptide index and oral disposition index (oDI) and 2) to explore whether CGM can be used to screen for OGTT-defined prediabetes and cystic fibrosis related diabetes (CFRD). Study Design/Methods PwCF not on insulin and healthy controls ages 6-25 yrs were enrolled in a prospective study collecting OGTT and CGM. A subset underwent frequently-sampled OGTTs (fsOGTT) with 7-point glucose, insulin, and C-peptide measurements. Pearson’s correlation coefficient was used to test the association between select CGM and fsOGTT measures. ROC analysis was applied to CGM variables to determine the cutoff optimizing sensitivity and specificity for detecting prediabetes and CFRD. Results A total of 120 participants (controls=35, CF=85), including 69 with fsOGTTs, were included. CGM coefficient of variation correlated inversely with C-peptide index (Cpeptide30-Cpeptide0/Glucose30-Glucose0) (r=-0.45, p<0.001) and oDIcpeptide (C-peptide index)(1/cpep0) (r=-0.48, p<0.0001). In PwCF, CGM variables had ROC-AUCs ranging from 0.43-0.57 for prediabetes and 0.47-0.6 for CFRD. Conclusions Greater glycemic variability on CGM correlated with reduced β-cell function. However, CGM performed poorly at discriminating individuals with and without OGTT-defined CFRD and prediabetes. Prospective studies are now needed to determine how well the different tests predict clinically-relevant non-glycemic outcomes in PwCF.

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