Autophagy regulates glucagon secretion via the beta2-adrenergic pathway
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ABSTRACT:
PROVIDER: PRJNA719161 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR14131966_1.fastq.gz | Fastqsanger.gz | |||
| SRR14131966_2.fastq.gz | Fastqsanger.gz | |||
| SRR14131967_1.fastq.gz | Fastqsanger.gz | |||
| SRR14131967_2.fastq.gz | Fastqsanger.gz | |||
| SRR14131968_1.fastq.gz | Fastqsanger.gz |
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Project description:Appropriate glucagon secretion from pancreatic alpha cells in response to hypoglycemia is an important component of maintaining glucose homeostasis. Dysregulated glucagon secretion leads to the delayed recovery from a hypoglycemic attack in type 1 diabetes patients which can be lethal. Although elucidating the precise mechanism of glucagon secretion in hypoglycemia is warranted, the underlying mechanism remains poorly understood.The present study provides evidence of the role of autophagy in glucagon secretion in hypoglycemia by demonstrating that autophagy regulates adrenergic stimulation of glucagon secretion downstream of beta2 adrenergic receptor. First, from the analyses of T1D human islets and the published database of scRNA-seq of T1D human alpha cells, we described autophagy pathways altered in T1D alpha cells. Second, we generated alpha cell-specific Atg7KO mice (alphaAtg7KO) and clarified that the lack of autophagy in alpha cells impairs the reactive glucagon secretion in acute hypoglycemia. Third, to interrogate the molecular mechanism of autophagy-mediated glucagon regulation, we analyzed top genes downregulated inT1D and T2D alpha cells and found the expression of beta2 adrenergic receptor showed significant down-regulation in T1D alpha cells. We confirmed the decreased expression of beta2 adrenergic receptor in alpha cells of the T1D pancreas section, the islets of alphaAtg7KO mice, and a murine alpha cell line with stable knockdown of Atg7. Furthermore, in vivo and ex vivo studies of alphaAtg7KO mice exhibited that lack of autophagy led to the loss of stimulatory effect of beta2-adrenergic signaling on glucagon secretion. Finally, we established the Atg7 knockdown model in sorted human alpha cells and confirmed the effect of autophagy on the expression of the beta2 adrenergic receptor. Together, our study provides novel insights into the regulatory role of autophagy in glucagon secretion in response to hypoglycemia and provides therapeutic options to achieve stable glycemic control in T1D patients.
2024-03-31 | GSE171352 | GEO
Project description:Glucagon and insulin are counter-regulatory pancreatic hormones that precisely control blood glucose homeostasis1. Type 2 diabetes mellitus (T2DM) is characterized by inappropriately elevated blood glucagon2-5 levels as well as insufficient glucose stimulated insulin secretion (GSIS) by pancreatic ß-cells6. Early in the pathogenesis of T2DM, hyperglucagonemia is observable antecedent to ß-cell dysfunction7-9; and in mice, liver-specific activation of glucagon receptor-dependent signaling results in impaired GSIS10. However, the mechanistic relationship between hyperglucagonemia, hepatic glucagon action, and ß-cell dysfunction remains poorly understood. Here we show that glucagon action stimulates hepatic production of the neuropeptide kisspeptin1, which acts in an endocrine manner on ß-cells to suppress GSIS. In vivo glucagon administration acutely stimulates hepatic kisspeptin1 production, and kisspeptin1 is increased in livers from humans with T2DM and from mouse models of diabetes mellitus. Synthetic kisspeptin1 potently suppresses GSIS in vivo and in vitro from normal isolated islets, which express the kisspeptin1 receptor Kiss1R. Administration of a Kiss1R antagonist in diabetic Leprdb/db mice potently augments GSIS and reduces glycemia. Our observations indicate in the pathogenesis of T2DM an endocrine mechanism sequentially linking hyperglucagonemia via hepatic kisspeptin1 production to impaired insulin secretion. In addition, our findings suggest Kiss1R antagonism as a therapeutic avenue to improve ß-cell function in T2DM. Total RNA from L-Δprkar1a KO mice compared to control D-glucose mice
2014-04-01 | E-GEOD-48815 | biostudies-arrayexpress
Project description:Glucagon receptor (GCGR) is a potential target for diabetes therapy. Several emerging GCGR antagonism-based therapies are under pre-clinical and clinical development. However, the GCGR antagonism as well as GCGR deficient animal accompanied with α-cell hyperplasia and hyperglucagonemia, which may limit the application of GCGR antagonism. To better understand the physiological changes in the α cells during the GCGR disruption, we performed the single cell sequencing of α cells isolated from control and gcgr-/- zebrafish. We found that α cells in gcgr-/- zebrafish dramatically increased glucagon (both gcga and gcgb) expression, we also found that several transcriptional factors that regulate glucagon expression were also increased. Based on the sequencing data, we further experimentally confirmed that gcgr-/- up-regulated glucagon mRNA level by in situ hybridization, and the gcgr-/- increased glucagon promoter activity indicated by reporter line Tg(gcga: GFP). Moreover, our results also revealed that α cells increased glucagon granule population and glucagon level in gcgr-/- zebrafish. These data suggested that hyperglucagonemia in the organism of GCGR antagonism not only contributed by the α-cell hyperplasia but also contributed by the increased glucagon expression and secretion from α cells. Our study provided more comprehensive understanding of physiological changes of α-cell during the GCGR disruption.
2022-10-26 | GSE179894 | GEO
Project description:Glucagon and insulin are counter-regulatory pancreatic hormones that precisely control blood glucose homeostasis1. Type 2 diabetes mellitus (T2DM) is characterized by inappropriately elevated blood glucagon2-5 levels as well as insufficient glucose stimulated insulin secretion (GSIS) by pancreatic ß-cells6. Early in the pathogenesis of T2DM, hyperglucagonemia is observable antecedent to ß-cell dysfunction7-9; and in mice, liver-specific activation of glucagon receptor-dependent signaling results in impaired GSIS10. However, the mechanistic relationship between hyperglucagonemia, hepatic glucagon action, and ß-cell dysfunction remains poorly understood. Here we show that glucagon action stimulates hepatic production of the neuropeptide kisspeptin1, which acts in an endocrine manner on ß-cells to suppress GSIS. In vivo glucagon administration acutely stimulates hepatic kisspeptin1 production, and kisspeptin1 is increased in livers from humans with T2DM and from mouse models of diabetes mellitus. Synthetic kisspeptin1 potently suppresses GSIS in vivo and in vitro from normal isolated islets, which express the kisspeptin1 receptor Kiss1R. Administration of a Kiss1R antagonist in diabetic Leprdb/db mice potently augments GSIS and reduces glycemia. Our observations indicate in the pathogenesis of T2DM an endocrine mechanism sequentially linking hyperglucagonemia via hepatic kisspeptin1 production to impaired insulin secretion. In addition, our findings suggest Kiss1R antagonism as a therapeutic avenue to improve ß-cell function in T2DM.
2014-04-01 | GSE48815 | GEO
Project description:The counterregulatory response to hypoglycemia, which restores normal blood glucose levels to ensure sufficient provision of glucose to the brain, is critical for survival. To discover underlying brain regulatory systems, we performed a genetic screen in recombinant inbred mice for quantitative trait loci (QTL) controlling glucagon secretion in response to neuroglucopenia. We identified a QTL on the distal part of chromosome 7 and combined this genetic information with transcriptomic analysis of hypothalami. This revealed Fgf15 as the strongest candidate to control the glucagon response. Fgf15 was found to be expressed by neurons of the dorsomedial hypothalamus and the perifornical area. Intracerebroventricular injection of FGF19, the human ortholog of Fgf15, reduced activation by neuroglucopenia of dorsal vagal complex neurons and of the parasympathetic nerve, leading to a lower glucagon secretion. These data show that Fgf15 in hypothalamic neurons is a regulator of vagal nerve activity in response to neuroglucopenia.
2016-11-07 | GSE87586 | GEO
Project description:Disruption of glucagon receptor increase α-cell glucagon expression and secretion beyond hyperplasia in zebrafish
| PRJNA745553 | ENA
Project description:Glucagon is secreted from pancreatic α-cells, and hypersecretion (hyperglucagonemia) contributes to diabetic hyperglycemia. Molecular heterogeneity in hyperglucagonemia is poorly investigated. By screening human plasma by high-resolution-proteomics, we identified several glucagon variants among which proglucagon 1-61 (PG 1-61) appears to be the most abundant form. PG 1-61 was secreted in obese subjects before and as well after gastric bypass surgery with protein and fat as the main drivers for secretion before surgery, but glucose after. Studies in hepatocytes and in β-cells demonstrated that PG 1-61 dose-dependently increased levels of cAMP, through the glucagon receptor, and increased insulin secretion and protein levels of enzymes regulating glycogenolysis and gluconeogenesis. As a consequence, PG 1-61 increased blood glucose and plasma insulin and decreased plasma levels of amino acids in vivo. Glucagon variants, such as PG 1-61, may contribute to glucose regulation by stimulating hepatic glucose production and insulin secretion.
2017-10-20 | PXD005677 | Pride
Project description:Dysregulation of glucagon secretion in type 1 diabetes (T1D) involves hypersecretion during postprandial states, but insufficient secretion during hypoglycemia. The sympathetic nervous system regulates glucagon secretion. To investigate islet sympathetic innervation in T1D, sympathetic tyrosine hydroxylase (TH) axons were analyzed in control non-diabetic organ donors, non-diabetic islet autoantibody-positive individuals (AAb), and age-matched persons with T1D. Islet TH axon numbers and density were significantly decreased in AAb compared to T1D with no significant differences observed in exocrine TH axon volume or lengths between groups. TH axons were in close approximation to islet α-cells in T1D individuals with long-standing diabetes. Islet RNA-sequencing and qRT-PCR analyses identified significant alterations in noradrenalin degradation, α-adrenergic signaling, cardiac b-adrenergic signaling, catecholamine biosynthesis, and additional neuropathology pathways. The close approximation of TH axons at islet α-cells supports a model for sympathetic efferent neurons directly regulating glucagon secretion. Sympathetic islet innervation and intrinsic adrenergic signaling pathways could be novel targets for improving glucagon secretion in T1D.
2021-08-09 | GSE181674 | GEO
Project description:Increasing evidence suggests an essential function for autophagy in unconventional protein secretion (UPS). However, despite its relevance for the secretion of aggregate-prone proteins, the mechanisms of secretory autophagy in neurons have remained elusive. Here we show that the lower motoneuron disease-associated protein Plekhg5 drives the UPS of Sod1. Mechanistically, Sod1 is sequestered into the intermembrane space of autophagosomes which fuse with secretory lysosomal-related organelles (LROs). Deletion of Plekhg5 in mice disrupts the secretion of these LROs causing Sod1 accumulation at swollen presynaptic sites. A reduced secretion of toxic ALS-linked SOD1G93A following deletion of Plekhg5 in SOD1G93A mice accelerated disease onset while prolonging survival due to an attenuated microglia activation. Using human isogenic iPSC-derived motoneurons we show an impaired secretion of ALS-linked SOD1D90A, which coincided with a reduced PLEKHG5 expression. Our findings highlight an unexpected pathophysiological mechanism that converges two motoneuron disease-associated proteins into a common pathway.
2024-08-28 | GSE269588 | GEO
Project description:Acute effects of beta2-adrenergic receptor activation on macrophage transcriptome
| PRJNA673830 | ENA