Single cell transcriptomics reveal trans-differentiation of pancreatic beta cells following inactivation of the TFIID subunit Taf4

AbstractRegulation of gene expression involves a complex and dynamic dialogue between transcription factors, chromatin remodelling and modification complexes and the basal transcription machinery. To address the function of the Taf4 subunit of general transcription factor TFIID in the regulation of insulin signalling, it was inactivated in adult murine pancreatic beta cells. Taf4 inactivation impacted the expression of critical genes involved in beta-cell function leading to increased glycaemia, lowered plasma insulin levels and defective glucose-stimulated insulin secretion. One week after Taf4-loss, single-cell RNA-seq revealed cells with mixed beta cell, alpha and/or delta cell identities as well as a beta cell population trans-differentiating into alpha-like cells. Computational analysis of single-cell RNA-seq defines how known critical beta cell and alpha cell determinants may act in combination with additional transcription factors and the NuRF chromatin remodelling complex to promote beta cell trans-differentiation.

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GLIS3 binds pancreatic beta cell regulatory regions alongside other islet transcription factors

Journal of Endocrinology ◽

10.1530/joe-19-0182 ◽

2019 ◽

Vol 243 (1) ◽

pp. 1-14 ◽

Cited By ~ 4

Author(s):

David W Scoville ◽

Kristin Lichti-Kaiser ◽

Sara A Grimm ◽

Anton M Jetten

Keyword(s):

Transcription Factors ◽

Beta Cell ◽

Beta Cells ◽

Beta Cell Function ◽

Pancreatic Beta Cells ◽

Cell Function ◽

Pancreatic Beta Cell ◽

Critical Role ◽

Regulatory Regions ◽

Insulin Expression

The Krüppel-like zinc finger transcription factor Gli-similar 3 (GLIS3) plays a critical role in the regulation of pancreatic beta cells, with global Glis3-knockout mice suffering from severe hyperglycemia and dying by post-natal day 11. In addition, GLIS3 has been shown to directly regulate the early endocrine marker Ngn3, as well as Ins2 gene expression in mature beta cells. We hypothesize that GLIS3 regulates several other genes critical to beta cell function, in addition to Ins2, by directly binding to regulatory regions. We therefore generated a pancreas-specific Glis3 deletion mouse model (Glis3Δ panc ) using a Pdx1-driven Cre mouse line. Roughly 20% of these mice develop hyperglycemia by 8 weeks and lose most of their insulin expression. However, this did not appear to be due to loss of the beta cells themselves, as no change in cell death was observed. Indeed, presumptive beta cells appeared to persist as PDX1+/INS−/MAFA−/GLUT2− cells. Islet RNA-seq analysis combined with GLIS3 ChIP-seq analysis revealed apparent direct regulation of a variety of diabetes-related genes, including Slc2a2 and Mafa. GLIS3 binding near these genes coincided with binding for other islet-enriched transcription factors, indicating these are distinct regulatory hubs. Our data indicate that GLIS3 regulates not only insulin expression, but also several additional genes critical for beta cell function.

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Multi-Organ Crosstalk with Endocrine Pancreas: A Focus on How Gut Microbiota Shapes Pancreatic Beta-Cells

Biomolecules ◽

10.3390/biom12010104 ◽

2022 ◽

Vol 12 (1) ◽

pp. 104

Author(s):

Elisa Fernández-Millán ◽

Carlos Guillén

Keyword(s):

Beta Cell ◽

Beta Cells ◽

Cell Biology ◽

Pancreatic Beta Cells ◽

Metabolic Diseases ◽

Cell Function ◽

Cell Mass ◽

Beta Cell Mass ◽

Short Chain Fatty Acids

Type 2 diabetes (T2D) results from impaired beta-cell function and insufficient beta-cell mass compensation in the setting of insulin resistance. Current therapeutic strategies focus their efforts on promoting the maintenance of functional beta-cell mass to ensure appropriate glycemic control. Thus, understanding how beta-cells communicate with metabolic and non-metabolic tissues provides a novel area for investigation and implicates the importance of inter-organ communication in the pathology of metabolic diseases such as T2D. In this review, we provide an overview of secreted factors from diverse organs and tissues that have been shown to impact beta-cell biology. Specifically, we discuss experimental and clinical evidence in support for a role of gut to beta-cell crosstalk, paying particular attention to bacteria-derived factors including short-chain fatty acids, lipopolysaccharide, and factors contained within extracellular vesicles that influence the function and/or the survival of beta cells under normal or diabetogenic conditions.

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Bergenin protects pancreatic beta cells against cytokine-induced apoptosis in INS-1E cells

PLoS ONE ◽

10.1371/journal.pone.0241349 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0241349

Author(s):

Sajid Ali Rajput ◽

Munazza Raza Mirza ◽

M. Iqbal Choudhary

Keyword(s):

Insulin Secretion ◽

Beta Cell ◽

Beta Cells ◽

Proinflammatory Cytokines ◽

Cell Apoptosis ◽

Pancreatic Beta Cells ◽

Cell Function ◽

Beta Cell Apoptosis ◽

Atp Levels ◽

Induced Apoptosis

Beta cell apoptosis induced by proinflammatory cytokines is one of the hallmarks of diabetes. Small molecules which can inhibit the cytokine-induced apoptosis could lead to new drug candidates that can be used in combination with existing therapeutic interventions against diabetes. The current study evaluated several effects of bergenin, an isocoumarin derivative, in beta cells in the presence of cytokines. These included (i) increase in beta cell viability (by measuring cellular ATP levels) (ii) suppression of beta cell apoptosis (by measuring caspase activity), (iii) improvement in beta cell function (by measuring glucose-stimulated insulin secretion), and (iv) improvement of beta cells mitochondrial physiological functions. The experiments were carried out using rat beta INS-1E cell line in the presence or absence of bergenin and a cocktail of proinflammatory cytokines (interleukin-1beta, tumor necrosis factor-alpha, and interferon- gamma) for 48 hr. Bergenin significantly inhibited beta cell apoptosis, as inferred from the reduction in the caspase-3 activity (IC50 = 7.29 ± 2.45 μM), and concurrently increased cellular ATP Levels (EC50 = 1.97 ± 0.47 μM). Bergenin also significantly enhanced insulin secretion (EC50 = 6.73 ± 2.15 μM) in INS-1E cells, presumably because of the decreased nitric oxide production (IC50 = 6.82 ± 2.83 μM). Bergenin restored mitochondrial membrane potential (EC50 = 2.27 ± 0.83 μM), decreased ROS production (IC50 = 14.63 ± 3.18 μM), and improved mitochondrial dehydrogenase activity (EC50 = 1.39 ± 0.62 μM). This study shows for the first time that bergenin protected beta cells from cytokine-induced apoptosis and restored insulin secretory function by virtue of its anti-inflammatory, antioxidant and anti-apoptotic properties. To sum up, the above mentioned data highlight bergenin as a promising anti-apoptotic agent in the context of diabetes.

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Update on the Protective Molecular Pathways Improving Pancreatic Beta-Cell Dysfunction

Mediators of Inflammation ◽

10.1155/2013/750540 ◽

2013 ◽

Vol 2013 ◽

pp. 1-14 ◽

Cited By ~ 14

Author(s):

Alessandra Puddu ◽

Roberta Sanguineti ◽

François Mach ◽

Franco Dallegri ◽

Giorgio Luciano Viviani ◽

...

Keyword(s):

Beta Cell ◽

Beta Cells ◽

Pancreatic Beta Cells ◽

Cell Function ◽

Pancreatic Beta Cell ◽

Cell Mass ◽

Beta Cell Mass ◽

Beta Cell Dysfunction ◽

Molecular Pathways ◽

Cell Dysfunction

The primary function of pancreatic beta-cells is to produce and release insulin in response to increment in extracellular glucose concentrations, thus maintaining glucose homeostasis. Deficient beta-cell function can have profound metabolic consequences, leading to the development of hyperglycemia and, ultimately, diabetes mellitus. Therefore, strategies targeting the maintenance of the normal function and protecting pancreatic beta-cells from injury or death might be crucial in the treatment of diabetes. This narrative review will update evidence from the recently identified molecular regulators preserving beta-cell mass and function recovery in order to suggest potential therapeutic targets against diabetes. This review will also highlight the relevance for novel molecular pathways potentially improving beta-cell dysfunction.

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Augmented mitochondrial energy metabolism is an early response to chronic glucose stress in human pancreatic beta cells

Diabetologia ◽

10.1007/s00125-020-05275-5 ◽

2020 ◽

Vol 63 (12) ◽

pp. 2628-2640

Author(s):

Isabelle Chareyron ◽

Stefan Christen ◽

Sofia Moco ◽

Armand Valsesia ◽

Steve Lassueur ◽

...

Keyword(s):

Energy Metabolism ◽

Beta Cell ◽

Beta Cells ◽

Pancreatic Beta Cells ◽

Cell Function ◽

Blood Glucose Control ◽

Calcium Signalling ◽

Cytosolic Calcium ◽

Metabolic Changes ◽

Mitochondrial Energy Metabolism

Abstract Aims/hypothesis In islets from individuals with type 2 diabetes and in islets exposed to chronic elevated glucose, mitochondrial energy metabolism is impaired. Here, we studied early metabolic changes and mitochondrial adaptations in human beta cells during chronic glucose stress. Methods Respiration and cytosolic ATP changes were measured in human islet cell clusters after culture for 4 days in 11.1 mmol/l glucose. Metabolomics was applied to analyse intracellular metabolite changes as a result of glucose stress conditions. Alterations in beta cell function were followed using insulin secretion assays or cytosolic calcium signalling after expression of the calcium probe YC3.6 specifically in beta cells of islet clusters. Results At early stages of glucose stress, mitochondrial energy metabolism was augmented in contrast to the previously described mitochondrial dysfunction in beta cells from islets of diabetic donors. Following chronic glucose stress, mitochondrial respiration increased (by 52.4%, p < 0.001) and, as a consequence, the cytosolic ATP/ADP ratio in resting human pancreatic islet cells was elevated (by 27.8%, p < 0.05). Because of mitochondrial overactivation in the resting state, nutrient-induced beta cell activation was reduced. In addition, chronic glucose stress caused metabolic adaptations that resulted in the accumulation of intermediates of the glycolytic pathway, the pentose phosphate pathway and the TCA cycle; the most strongly augmented metabolite was glycerol 3-phosphate. The changes in metabolites observed are likely to be due to the inability of mitochondria to cope with continuous nutrient oversupply. To protect beta cells from chronic glucose stress, we inhibited mitochondrial pyruvate transport. Metabolite concentrations were partially normalised and the mitochondrial respiratory response to nutrients was markedly improved. Furthermore, stimulus–secretion coupling as assessed by cytosolic calcium signalling, was restored. Conclusion/interpretation We propose that metabolic changes and associated mitochondrial overactivation are early adaptations to glucose stress, and may reflect what happens as a result of poor blood glucose control. Inhibition of mitochondrial pyruvate transport reduces mitochondrial nutrient overload and allows beta cells to recover from chronic glucose stress.

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PCSK9 affects expression of key surface proteins in human pancreatic beta cells through intra- and extracellular regulatory circuits

10.1101/2021.09.28.461975 ◽

2021 ◽

Author(s):

kevin Saitoski ◽

Maria Ryaboshapkina ◽

Ghaith Hamza ◽

Andrew F Jarnuczak ◽

claire berthault ◽

...

Keyword(s):

Transcription Factors ◽

Beta Cell ◽

Pancreatic Islets ◽

Cell Line ◽

Beta Cells ◽

Pancreatic Beta Cells ◽

Pancreatic Beta Cell ◽

Loss Of Function ◽

Beta Cell Line ◽

Gain And Loss

Aims/hypothesis: Proprotein convertase subtilisin/kexin 9 (PCSK9) is involved in the degradation of LDLR. However, PCSK9 can target other proteins in a cell-type specific manner. While PCSK9 has been detected in pancreatic islets, its expression in insulin-producing pancreatic beta cells is debated. Herein, we studied PCSK9 expression, regulation and function in the human pancreatic beta cell line EndoC-βH1. Methods: We assessed PCSK9 expression in mouse and human pancreatic islets, and in the pancreatic beta cell line EndoC-βH1. We also studied PCSK9 regulation by cholesterol, lipoproteins, Mevastatin, and by SREBPs transcription factors. To evaluate PCSK9 function in pancreatic beta cells, we performed PCSK9 gain-and loss-of-function experiments in EndoC-βH1 using siPCSK9 or recombinant PCSK9 treatments, respectively. Results: We demonstrate that PCSK9 is expressed and secreted by pancreatic beta cells. In EndoC-βH1 cells, PCSK9 expression is regulated by cholesterol and by SREBPs transcription factors. Importantly, PCSK9 knockdown results in multiple transcriptome, proteome and secretome deregulations and impaired insulin secretion. By gain- and loss-of- function experiments, we observed that PCSK9 regulates the expression levels of LDLR and VLDLR through an extracellular mechanism while CD36, PD-L1 and HLA-ABC are regulated through an intracellular mechanism. Conclusions/interpretation: Collectively, these results highlight PCSK9 as an important regulator of CD36, PD-L1 and HLA-ABC cell surface expression in pancreatic beta cells. Data availability: RNA-seq data have been deposited to GEO database with accession number GSE182016. Mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the following identifiers: PXD027921, PXD027911 and PXD027913.

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Pancreatic beta-cell-type-specific expression of the rat insulin II gene is controlled by positive and negative cellular transcriptional elements.

Molecular and Cellular Biology ◽

10.1128/mcb.9.8.3253 ◽

1989 ◽

Vol 9 (8) ◽

pp. 3253-3259 ◽

Cited By ~ 66

Author(s):

J Whelan ◽

D Poon ◽

P A Weil ◽

R Stein

Keyword(s):

Transcription Factors ◽

Beta Cell ◽

Beta Cells ◽

Pancreatic Beta Cells ◽

Pancreatic Beta Cell ◽

Cell Type ◽

Specific Expression ◽

Cis Acting ◽

Cell Type Specific Expression ◽

Cell Type Specific

The insulin gene is expressed almost exclusively in pancreatic beta-cells. The DNA sequences that control cell-specific expression are located upstream of the transcription initiation site. To identify the cis-acting transcriptional control regions within the rat insulin II gene that are responsible for this tissue-specific expression pattern, we constructed a series of 5'-flanking deletion mutants and analyzed their expression in vivo in transfected insulin-producing and -nonproducing cell lines. Pancreatic beta-cell-specific expression was shown to be controlled by enhancer sequences lying between nucleotides -342 and -91 relative to the transcription start site. The rat insulin II enhancer appears to be a chimera, composed of a number of distinct cis-acting DNA elements. Both positive and negative transcriptional regulatory elements appear to be responsible for this cell-type-specific expression. We have shown that expression from one element within the enhancer, which is found between nucleotides -100 and -91, is regulated by both positive- and negative-acting cellular transcription factors. Expression from chimeras containing only the enhancer element sequences from -100 to -91 were active only in insulin-producing cells, indicating that the positive-acting factor(s) required for this activity may be active only in beta-cells. In contrast to the enhancer region, the rat insulin II gene promoter did not appear to require cell-specific transcription factors. Promoter mutants with 5'-flanking sequences extending to nucleotides -90 and -73 were constitutively active in both insulin-producing and -nonproducing cells. These results suggest that rat insulin II gene transcription in pancreatic beta-cells is imparted by a combination of both negative- and positive-acting cellular factors interacting with the gene enhancer.

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Activation of Aldehyde Dehydrogenase 2 Ameliorates Glucolipotoxicity of Pancreatic Beta Cells

Biomolecules ◽

10.3390/biom11101474 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1474

Author(s):

Shiau-Mei Chen ◽

Siow-Wey Hee ◽

Shih-Yun Chou ◽

Meng-Wei Liu ◽

Che-Hong Chen ◽

...

Keyword(s):

Insulin Secretion ◽

Beta Cell ◽

Beta Cells ◽

Aldehyde Dehydrogenase ◽

Mitochondrial Function ◽

Beta Cell Function ◽

Pancreatic Beta Cells ◽

Cell Function ◽

Aldehyde Dehydrogenase 2 ◽

Min6 Cells

Chronic hyperglycemia and hyperlipidemia hamper beta cell function, leading to glucolipotoxicity. Mitochondrial aldehyde dehydrogenase 2 (ALDH2) detoxifies reactive aldehydes, such as methylglyoxal (MG) and 4-hydroxynonenal (4-HNE), derived from glucose and lipids, respectively. We aimed to investigate whether ALDH2 activators ameliorated beta cell dysfunction and apoptosis induced by glucolipotoxicity, and its potential mechanisms of action. Glucose-stimulated insulin secretion (GSIS) in MIN6 cells and insulin secretion from isolated islets in perifusion experiments were measured. The intracellular ATP concentrations and oxygen consumption rates of MIN6 cells were assessed. Furthermore, the cell viability, apoptosis, and mitochondrial and intracellular reactive oxygen species (ROS) levels were determined. Additionally, the pro-apoptotic, apoptotic, and anti-apoptotic signaling pathways were investigated. We found that Alda-1 enhanced GSIS by improving the mitochondrial function of pancreatic beta cells. Alda-1 rescued MIN6 cells from MG- and 4-HNE-induced beta cell death, apoptosis, mitochondrial dysfunction, and ROS production. However, the above effects of Alda-1 were abolished in Aldh2 knockdown MIN6 cells. In conclusion, we reported that the activator of ALDH2 not only enhanced GSIS, but also ameliorated the glucolipotoxicity of beta cells by reducing both the mitochondrial and intracellular ROS levels, thereby improving mitochondrial function, restoring beta cell function, and protecting beta cells from apoptosis and death.

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Arginase 2 and Polyamines in Human Pancreatic Beta Cells: Possible Role in the Pathogenesis of Type 2 Diabetes

International Journal of Molecular Sciences ◽

10.3390/ijms222212099 ◽

2021 ◽

Vol 22 (22) ◽

pp. 12099

Author(s):

Lorella Marselli ◽

Emanuele Bosi ◽

Carmela De Luca ◽

Silvia Del Guerra ◽

Marta Tesi ◽

...

Keyword(s):

Type 2 Diabetes ◽

Beta Cell ◽

Beta Cells ◽

Beta Cell Function ◽

Pancreatic Beta Cells ◽

Cell Function ◽

Pancreas Development ◽

Tissue Specific

Arginase 2 (ARG2) is a manganese metalloenzyme involved in several tissue specific processes, from physiology to pathophysiology. It is variably expressed in extra-hepatic tissues and is located in the mitochondria. In human pancreatic beta cells, ARG2 is downregulated in type 2 diabetes. The enzyme regulates the synthesis of polyamines, that are involved in pancreas development and regulation of beta cell function. Here, we discuss several features of ARG2 and polyamines, which can be relevant to the pathophysiology of type 2 diabetes.

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Imaging Beta-Cell Function in the Pancreas of Non-Human Primates Using a Zinc-Sensitive MRI Contrast Agent

Frontiers in Endocrinology ◽

10.3389/fendo.2021.641722 ◽

2021 ◽

Vol 12 ◽

Author(s):

Veronica Clavijo Jordan ◽

Catherine D. G. Hines ◽

Liza T. Gantert ◽

Shubing Wang ◽

Stacey Conarello ◽

...

Keyword(s):

Beta Cell ◽

Contrast Agent ◽

Contrast Enhancement ◽

Beta Cells ◽

Beta Cell Function ◽

Pancreatic Beta Cells ◽

Cell Function ◽

Mri Contrast Agent ◽

C Peptide

Non-invasive beta cell function measurements may provide valuable information for improving diabetes diagnostics and disease management as the integrity and function of pancreatic beta cells have been found to be compromised in Type-1 and Type-2 diabetes. Currently, available diabetes assays either lack functional information or spatial identification of beta cells. In this work, we introduce a method to assess the function of beta cells in the non-human primate pancreas non-invasively with MRI using a Gd-based zinc(II) sensor as a contrast agent, Gd-CP027. Additionally, we highlight the role of zinc(II) ions in the paracrine signaling of the endocrine pancreas via serological measurements of insulin and c-peptide. Non-human primates underwent MRI exams with simultaneous blood sampling during a Graded Glucose Infusion (GGI) with Gd-CP027 or with a non-zinc(II) sensitive contrast agent, gadofosveset. Contrast enhancement of the pancreas resulting from co-release of zinc(II) ion with insulin was observed focally when using the zinc(II)-specific agent, Gd-CP027, whereas little enhancement was detected when using gadofosveset. The contrast enhancement detected by Gd-CP027 increased in parallel with an increased dose of infused glucose. Serological measurements of C-peptide and insulin indicate that Gd-CP027, a high affinity zinc(II) contrast agent, potentiates their secretion only as a function of glucose stimulation. Taken in concert, this assay offers the possibility of detecting beta cell function in vivo non-invasively with MRI and underscores the role of zinc(II) in endocrine glucose metabolism.

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