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PROVIDER: PRJNA795174 | ENA |
REPOSITORIES: ENA
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Project description:OCaR1, a gatekeeper of lysosomal and granular Ca2+ release and regulated exocytosis
| PRJNA434189 | ENA
Project description:During exocytosis, a Ca2+ increase arises in close vicinity of secretory granules which is strictly prevented in resting cells. Granular Ca2+ homeostasis and its role in granular exocytosis are not well understood.
2018-08-14 | GSE110646 | GEO
Project description:Nonalcoholic steatohepatitis (NASH) is a progressive disorder with aberrant lipid accumulation and subsequent inflammatory and profibrotic response. Lipid reduction through cytoplasmic lipolysis might adversely worsen steatohepatitis, however, the effect of autophagic lipolysis, lipophagy, remains obscure. We engineered the adaptor protein to induce lipophagy with lipid droplet targeting signal and modified LC3 interacting region. Activating hepatocyte lipophagy obviously mitigated both steatosis and NASH pathology. Mechanistically, lipophagy promoted the excretion of lipid from liver via lysosomal exocytosis and attenuated harmful accumulation of nonesterified fatty acid. This exocytosis was dependent on Ca2+ signal unlike the lysosomal dysfunction-related exocytosis. High content compound screening identified alpelisib and digoxin, clinically-approved compounds, as effective activators of lipophagy. Administration of alpelisib or digoxin inhibited the transition to steatohepatitis in mice fed high fat with low methionine low choline diet. Given all these data, activating lipophagy may be a promising therapeutic approach to prevent NASH progression.
2023-05-15 | GSE185911 | GEO
Project description:To investigate the putative differential effect of chloride transport on lysosomal ion homeostasis,we generated an ODE mathematical model for this system. Our mathematical model builds upon a previously published model for lysosomal homeostasis (Grabe et al. 2001 J. Gen. Physiol, Ishida et al. 2013 J. Gen. Physiol), and further includes the (de)activation kinetics of the ClC-7 antiporter and Ca2+ uptake/release mechanisms. Our new model tracks the total number of ions within the lysosomal lumen over time. It considers different types of lysosomal ion channels and exchangers and two possible lysosomal Ca2+ transporters. The variation in the total number of each ion within the lysosome is described by an ordinary differential equation (ODE), and the rate of change is determined by the flux of the corresponding ion across the lysosomal membrane. The model considers different elements affecting lysosomal ion homeostasis, among which are: (i) the V-ATPase pump, (ii) a proton leak, (iii) the luminal proton buffering capacity, (iv) ClC-7 chloride/proton exchanger, (v) Ca2+ /proton exchanger (CAX), (vi) passive channels for K+ , Na+ , and Ca2+ , and (vii) Donnan particles, which are negatively charged particles or molecules trapped in the lysosomal lumen. It allows for the simulation of different scenarios mimicking the differential transport of chloride, its impact on Ca2+ uptake and release and ultimately on lysosomal homeostasis. We provide a Supplementary Information file (Astaburuaga et al. Cells 2019) with the full description of the mathematical model. The equations written in purple were newly developed, the other elements were retrieved from a previous mathematical model as indicated above.
2019-10-22 | MODEL1910220001 | BioModels
Project description:The molecular mechanism regulating phasic corticotropin-releasing hormone (CRH) release from parvocellular neurons (PVN) remains poorly understood. Here, we find a cohort of parvocellular cells interspersed with magnocellular PVN neurons expressing secretagogin. Single-cell transcriptome analysis combined with protein interactome profiling identifies secretagogin neurons as a distinct CRH-releasing neuron population reliant on secretagogin’s Ca2+ sensor properties and protein interactions with the vesicular traffic and exocytosis release machineries to liberate this key hypothalamic releasing hormone.
2014-11-20 | GSE63093 | GEO
Project description:The molecular mechanism regulating phasic corticotropin-releasing hormone (CRH) release from parvocellular neurons (PVN) remains poorly understood. Here, we find a cohort of parvocellular cells interspersed with magnocellular PVN neurons expressing secretagogin. Single-cell transcriptome analysis combined with protein interactome profiling identifies secretagogin neurons as a distinct CRH-releasing neuron population reliant on secretagoginM-bM-^@M-^Ys Ca2+ sensor properties and protein interactions with the vesicular traffic and exocytosis release machineries to liberate this key hypothalamic releasing hormone. single cells from the PVN region juvenile (21-28 days) mice were dissected and subject to whole transcriptome analysis
2014-11-20 | E-GEOD-63093 | biostudies-arrayexpress
Project description:In order to gain further insight into the molecular mechanism(s) mediating the blunted epinephrine responses following recurrent hypoglycemia we utilized global gene expression profiling approach. Our results indicate the association between defective counterregulation (impaired epinephrine release) and the activation of the unfolded protein response as well as increased neuropeptide signaling, altered ion homeostasis and downregulation of proteins involved in Ca2+-dependent exocytosis of secretory vesicles.
2016-07-01 | GSE82145 | GEO
Project description:In order to gain further insight into the molecular mechanism(s) mediating the blunted epinephrine responses following recurrent hypoglycemia we utilized global gene expression profiling approach. Our results indicate the association between defective counterregulation (impaired epinephrine release) and the activation of the unfolded protein response as well as increased neuropeptide signaling, altered ion homeostasis and downregulation of proteins involved in Ca2+-dependent exocytosis of secretory vesicles. We compared the entire transcriptomes during recurrent (defective CRR model, 2RH) and acute hypoglycemia (normal CRR group, 2RS) in the adrenal medulla of normal Sprague-Dawley rats.
2016-07-01 | E-GEOD-82145 | biostudies-arrayexpress
Project description:Background: Tetraspanin-7 (Tspan7) is an islet autoantigen involved in autoimmune type 1 diabetes and known to regulate beta-cell L-type Ca2+ channel activity. However, the role of Tspan7 in pancreatic beta-cell function is not yet fully understood. Methods: Histological analyses were conducted using immunostaining. Whole-body metabolism was tested using glucose tolerance test. Islet hormone secretion was quantified using static batch incubation or dynamic perifusion. Beta-cell transmembrane currents, electrical activity and exocytosis were measured using whole-cell patch-clamping and capacitance measurements. Gene expression was studied using mRNA-sequencing and quantitative PCR. Results: Tspan7 is expressed in insulin-containing granules of pancreatic beta-cells. Tspan7-knockout mice (Tspan7 y/- mouse) exhibit reduced body weight and ad libitum plasma glucose but normal glucose tolerance. Tspan7y/- islets have normal insulin content and glucose- or tolbutamide-stimulated insulin secretion. Depolarisation-triggered Ca2+ current was enhanced in Tspan7y/- beta-cells, but beta-cell electrical activity and depolarisation-evoked exocytosis were unchanged suggesting that exocytosis was less sensitive to Ca2+. TSPAN7 knockdown (KD) in human pseudo-islets led to a significant reduction in high K+-stimulated insulin secretion. Transcriptomic analyses show that TSPAN7 KD in human pseudo-islets correlated with changes in genes involved in hormone secretion, apoptosis and ER stress. Consistent with rodent beta-cells, exocytotic Ca2+ sensitivity was reduced in a human beta cell line (EndoC-bH1) following Tspan7 KD. Conclusion: Tspan7 is involved in the regulation of Ca2+-dependent exocytosis in beta-cells. Its function is more significant in human beta-cells than their rodent counterparts
2022-10-10 | GSE213729 | GEO
Project description:Background: Tetraspanin-7 (Tspan7) is an islet autoantigen involved in autoimmune type 1 diabetes and known to regulate beta-cell L-type Ca2+ channel activity. However, the role of Tspan7 in pancreatic beta-cell function is not yet fully understood. Methods: Histological analyses were conducted using immunostaining. Whole-body metabolism was tested using glucose tolerance test. Islet hormone secretion was quantified using static batch incubation or dynamic perifusion. Beta-cell transmembrane currents, electrical activity and exocytosis were measured using whole-cell patch-clamping and capacitance measurements. Gene expression was studied using mRNA-sequencing and quantitative PCR. Results: Tspan7 is expressed in insulin-containing granules of pancreatic beta-cells. Tspan7-knockout mice (Tspan7 y/- mouse) exhibit reduced body weight and ad libitum plasma glucose but normal glucose tolerance. Tspan7y/- islets have normal insulin content and glucose- or tolbutamide-stimulated insulin secretion. Depolarisation-triggered Ca2+ current was enhanced in Tspan7y/- beta-cells, but beta-cell electrical activity and depolarisation-evoked exocytosis were unchanged suggesting that exocytosis was less sensitive to Ca2+. TSPAN7 knockdown (KD) in human pseudo-islets led to a significant reduction in high K+-stimulated insulin secretion. Transcriptomic analyses show that TSPAN7 KD in human pseudo-islets correlated with changes in genes involved in hormone secretion, apoptosis and ER stress. Consistent with rodent beta-cells, exocytotic Ca2+ sensitivity was reduced in a human beta cell line (EndoC-H1) following Tspan7 KD. Conclusion: Tspan7 is involved in the regulation of Ca2+-dependent exocytosis in beta-cells. Its function is more significant in human beta-cells than their rodent counterparts
2022-10-10 | GSE213730 | GEO