Triton X-100 inhibits L-type voltage-operated calcium channels

2013 ◽  
Vol 91 (4) ◽  
pp. 316-324 ◽  
Author(s):  
Deepak Narang ◽  
Paul M. Kerr ◽  
Jason Baserman ◽  
Raymond Tam ◽  
Wei Yang ◽  
...  
Keyword(s):  
Calcium Channels ◽  
Cell Types ◽  
Resistance Arteries ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Functional Studies ◽  
Cell Functions ◽  
Nonionic Detergent ◽  
Triton X ◽  
Voltage Operated Calcium Channels

Triton X-100 (TX-100) is a nonionic detergent frequently used at millimolar concentrations to disrupt cell membranes and solubilize proteins. At low micromolar concentrations, TX-100 has been reported to inhibit the function of potassium channels. Here, we have used electrophysiological and functional techniques to examine the effects of TX-100 on another class of ion channels, L-type voltage-operated calcium channels (VOCCs). TX-100 (30 nmol·L–1 to 3 μmol·L–1) caused reversible concentration-dependent inhibition of recombinant L-type VOCC (CaV 1.2) currents and of native L-type VOCC currents recorded from rat vascular smooth muscle cells and cardiac myocytes, and murine and human pancreatic β-cells. In functional studies, TX-100 (165 nmol·L–1 to 3.4 μmol·L–1) caused concentration-dependent relaxation of rat isolated mesenteric resistance arteries prestimulated with phenylephrine or KCl. This effect was independent of the endothelium. TX-100 (1.6 μmol·L–1) inhibited depolarization-induced exocytosis in both murine and human isolated pancreatic β-cells. These data indicate that at concentrations within the nanomolar to low micromolar range, TX-100 significantly inhibits L-type VOCC activity in a number of cell types, an effect paralleled by inhibition of cell functions dependent upon activation of these channels. This inhibition occurs at concentrations below those used to solubilize proteins and may compromise the use of solutions containing TX-100 in bioassays.

Dihydropyridine-sensitive and -insensitive voltage-operated calcium channels participate in the control of glucose-induced insulin release from human pancreatic β cells

1996 ◽  
Vol 150 (2) ◽  
pp. 195-203 ◽  
Author(s):  
A M Davalli ◽  
E Biancardi ◽  
A Pollo ◽  
C Socci ◽  
A E Pontiroli ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Calcium Channels ◽  
Insulin Release ◽  
High Voltage ◽  
Human Islets ◽  
Bay K 8644 ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Patch Clamp Technique ◽  
Voltage Operated Calcium Channels

Abstract Calcium ion entry through voltage-operated calcium channels is a crucial step in the coupling of β cell depolarization with insulin secretion. Various calcium channel subtypes have been shown to be coexpressed in single neurons and endocrine cells. Using the patch-clamp technique, we investigated the biophysical and pharmacological properties of calcium channels in freshly dispersed human pancreatic β cells. Both low and high voltage activated currents were expressed, the two current types being easily distinguishable on the basis of biophysical criteria. The high voltage activated currents were not homogeneous: one component was affected by the dihydropyridine antagonist nitrendipine and the agonist Bay-K-8644; the other was insensitive to both dihydropyridines and ω-conotoxin GVIA. In line with this pharmacology, nitrendipine reduced and Bay-K-8644 increased glucose-induced insulin secretion from perifused human islets, whereas ω-conotoxin GVIA had no effect. However, about 20% of the glucose-induced insulin release was found to be resistant to high nitrendipine concentrations. These data show that human pancreatic β cells express heterogeneous voltage-operated calcium channels, only one of which is dihydropyridine-sensitive (L type). The L type channels are clearly involved in the control of insulin secretion, but our data suggest that dihydropyridine- and ω-conotoxin GVIA-insensitive channels may also play a role in the stimulus-secretion coupling of human β cells. Journal of Endocrinology (1996) 150, 195–203

scholarly journals Triton X‐100 inhibits L‐type voltage‐operated calcium channels

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Deepak Narang ◽  
Paul M Kerr ◽  
Jason Baserman ◽  
Raymond Tam ◽  
Gavin Searle ◽  
...  
Keyword(s):  
Calcium Channels ◽  
Triton X ◽  
Voltage Operated Calcium Channels

scholarly journals A new class of calcium channels activated by glucose in human pancreatic β-cells

FEBS Letters ◽  
1990 ◽  
Vol 261 (2) ◽  
pp. 265-270 ◽  
Author(s):  
Eduardo Rojas ◽  
Jorge Hidalgo ◽  
Patricia B. Carroll ◽  
Min Xu Li ◽  
Illani Atwater
Keyword(s):  
Calcium Channels ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
New Class

scholarly journals Neuroligin-2-derived peptide-covered polyamidoamine-based (PAMAM) dendrimers enhance pancreatic β-cells' proliferation and functions

MedChemComm ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 280-293
Author(s):  
Anna Munder ◽  
Yoni Moskovitz ◽  
Aviv Meir ◽  
Shirin Kahremany ◽  
Laura Levy ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Cellular Stress ◽  
Pamam Dendrimers ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Cell Functions ◽  
Functional Maturation ◽  
Glucose Stimulated Insulin Secretion

The nanoscale composite improved β-cell functions in terms of rate of proliferation, glucose-stimulated insulin secretion, resistance to cellular stress and functional maturation.

scholarly journals Differential cell autonomous responses determine the outcome of coxsackievirus infections in murine pancreatic α and β cells

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Laura Marroqui ◽  
Miguel Lopes ◽  
Reinaldo S dos Santos ◽  
Fabio A Grieco ◽  
Merja Roivainen ◽  
...  
Keyword(s):  
Gene Networks ◽  
Viral Infections ◽  
Islet Cells ◽  
Global Gene Expression ◽  
Cell Types ◽  
Autoimmune Response ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Antiviral Responses ◽  
Different Cell Types

Type 1 diabetes (T1D) is an autoimmune disease caused by loss of pancreatic β cells via apoptosis while neighboring α cells are preserved. Viral infections by coxsackieviruses (CVB) may contribute to trigger autoimmunity in T1D. Cellular permissiveness to viral infection is modulated by innate antiviral responses, which vary among different cell types. We presently describe that global gene expression is similar in cytokine-treated and virus-infected human islet cells, with up-regulation of gene networks involved in cell autonomous immune responses. Comparison between the responses of rat pancreatic α and β cells to infection by CVB5 and 4 indicate that α cells trigger a more efficient antiviral response than β cells, including higher basal and induced expression of STAT1-regulated genes, and are thus better able to clear viral infections than β cells. These differences may explain why pancreatic β cells, but not α cells, are targeted by an autoimmune response during T1D.

scholarly journals Identification of a novel lncRNA (G3R1) regulated by GLIS3 in pancreatic β-cells

2020 ◽  
Vol 65 (3) ◽  
pp. 59-67
Author(s):  
David W Scoville ◽  
Artiom Gruzdev ◽  
Anton M Jetten
Keyword(s):  
Pancreatic Islets ◽  
Knockout Mouse ◽  
Cell Function ◽  
Significant Loss ◽  
Messenger Rnas ◽  
Β Cells ◽  
Β Cell ◽  
Pancreatic Β Cells ◽  
Phenotypic Analysis ◽  
Cell Functions

Recent advances in high throughput RNA sequencing have revealed that, in addition to messenger RNAs (mRNAs), long non-coding RNAs (lncRNAs) play an important role in the regulation of many cell functions and of organ development. While a number of lncRNAs have been identified in pancreatic islets, their function remains largely undetermined. Here, we identify a novel long ncRNA regulated by the transcription factor GLIS3, which we refer to as GLIS3 regulated 1 (G3R1). This lncRNA was identified for its significant loss of expression in GLIS3 knockout mouse pancreatic islets. G3R1 appears to be specifically expressed in mouse pancreatic β-cells and in a β-cell line (βTC-6). ChIP-seq analysis indicated that GLIS3 and other islet-enriched transcription factors bind near the G3R1 gene, suggesting they directly regulate G3R1 transcription. Similarly, an apparent human homolog of G3R1 displays a similar expression pattern, with additional expression seen in human brain. In order to determine the function of G3R1 in mouse pancreatic β-cells, we utilized CRISPR to develop a knockout mouse where ~80% of G3R1 sequence is deleted. Phenotypic analysis of these mice did not reveal any impairment in β-cell function or glucose regulation, indicating the complexity underlying the study of lncRNA function.

scholarly journals A pipeline for multidimensional confocal analysis of mitochondrial morphology, function and dynamics in pancreatic β-cells

2019 ◽  
Author(s):  
Ahsen Chaudhry ◽  
Rocky Shi ◽  
Dan S. Luciani
Keyword(s):  
Metabolic Diseases ◽  
Super Resolution ◽  
Cell Types ◽  
Mitochondrial Morphology ◽  
State Function ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Health And Disease ◽  
Mitochondrial Networks ◽  
Functional Analyses

ABSTRACTLive-cell imaging of mitochondrial function and dynamics can provide vital insights into both physiology and pathophysiology, including of metabolic diseases like type 2 diabetes. However, without super-resolution microscopy and commercial analysis software it is challenging to accurately extract features from dense multi-layered mitochondrial networks, such as those in insulin-secreting pancreatic β-cells. Motivated by this, we developed a comprehensive pipeline, and associated ImageJ plugin, that enables 2D/3D quantification of mitochondrial network morphology and dynamics in mouse β-cells, and by extension other similarly challenging cell-types. The approach is based on standard confocal microscopy and shareware, making it widely accessible. The pipeline was validated using mitochondrial photo-labelling and unsupervised cluster analysis, and is capable of morphological and functional analyses on a per-organelle basis, including in 4D (xyzt). Overall, this tool offers a powerful framework for multiplexed analysis of mitochondrial state/function, and provides a valuable resource to accelerate mitochondrial research in health and disease.

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