Low Concentrations of Arsenite Target the Intraluminal Inositol 1, 4, 5-Trisphosphate Receptor/Ryanodine Receptor Crosstalk to Significantly Elevate Intracellular Ca2+

Abstract Background Podocyte injury plays a key role in the development of proteinuria. We previously found that the intracellular inositol 1, 4, 5-trisphosphate receptor (IP3R)- glucose-regulated protein 75 (Grp75)- voltage dependent anion channel 1 (VDAC1)- mitochondrial calcium uniporter (MCU) calcium axis contributes to podocyte injury in cultured mouse podocytes. Objective This study investigated whether the IP3R-Grp75-VDAC1-MCU calcium axis is involved in the development and improvement of proteinuria in nephropathy rats.Methods The expression of members of the IP3R-Grp75-VDAC1-MCU calcium axis in the renal cortex of a previously established adriamycin (ADR)-induced nephropathy rat model and cultured mouse podocytes was investigated by western blot analysis and immunohistochemical staining. The effects of ruthenium red (RR), an MCU inhibitor, oninteractions in the IP3R-Grp75-VDAC1-MCU calcium axis were investigated by in vitro co-immunoprecipitation assays.Results The overexpression and inhibition of members of the glomerular IP3R-Grp75-VDAC1-MCU calcium axis were accompanied by the development and improvement of proteinuria, respectively, in nephropathy rats. RR inhibited the upregulation of members of the IP3R-Grp75-VDAC1-MCU calcium axis induced by ADR and their interactions. Conclusions The IP3R-Grp75-VDAC1-MCU calcium axis is involved in proteinuria in ADR-induced nephropathy and can be inhibited by RR.

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Ca2+ signals mediated by Ins(1,4,5)P3-gated channels in rat ureteric myocytes

Biochemical Journal ◽

10.1042/bj3490323 ◽

2000 ◽

Vol 349 (1) ◽

pp. 323-332 ◽

Cited By ~ 24

Author(s):

François-Xavier BOITTIN ◽

Frédéric COUSSIN ◽

Jean-Luc MOREL ◽

Guillaume HALET ◽

Nathalie MACREZ ◽

...

Keyword(s):

Ryanodine Receptor ◽

Time Course ◽

Binding Capacity ◽

Ryanodine Receptors ◽

Initiation Site ◽

Variable Number ◽

Spatial Spread ◽

Receptor Antibody ◽

Low Concentrations ◽

High Level

Localized Ca2+-release signals (puffs) and propagated Ca2+ waves were characterized in rat ureteric myocytes by confocal microscopy. Ca2+ puffs were evoked by photorelease of low concentrations of Ins(1,4,5)P3 from a caged precursor and by low concentrations of acetylcholine; they were also observed spontaneously in Ca2+-overloaded myocytes. Ca2+ puffs showed some variability in amplitude, time course and spatial spread, suggesting that Ins(1,4,5)P3-gated channels exist in clusters containing variable numbers of channels and that within these clusters a variable number of channels can be recruited. Immunodetection of Ins(1,4,5)P3 receptors revealed the existence of several spots of fluorescence in the confocal cell sections, supporting the existence of clusters of Ins(1,4,5)P3 receptors. Strong Ins(1,4,5)P3 photorelease and high concentrations of acetylcholine induced Ca2+ waves that originated from an initiation site and propagated in the whole cell by spatial recruitment of neighbouring Ca2+-release sites. Both Ca2+ puffs and Ca2+ waves were blocked selectively by intracellular applications of heparin and an anti-Ins(1,4,5)P3-receptor antibody, but were unaffected by ryanodine and intracellular application of an anti-ryanodine receptor antibody. mRNAs encoding for the three subtypes of Ins(1,4,5)P3 receptor and subtype 3 of ryanodine receptor were detected in these myocytes, and the maximal binding capacity of [3H]Ins(1,4,5)P3 was 10- to 12-fold higher than that of [3H]ryanodine. These results suggest that Ins(1,4,5)P3-gated channels mediate a continuum of Ca2+ signalling in smooth-muscle cells expressing a high level of Ins(1,4,5)P3 receptors and no subtypes 1 and 2 of ryanodine receptors.

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Relationship between hormonal activation of phosphatidylinositol hydrolysis, fluid secretion and calcium flux in the blowfly salivary gland

Biochemical Journal ◽

10.1042/bj1780045 ◽

1979 ◽

Vol 178 (1) ◽

pp. 45-58 ◽

Cited By ~ 143

Author(s):

J N Fain ◽

M J Berridge

Keyword(s):

Salivary Gland ◽

Fluid Secretion ◽

Salivary Secretion ◽

Calcium Flux ◽

Ionophore A23187 ◽

Bivalent Cation ◽

Inositol 1 ◽

Low Concentrations ◽

Hormonal Activation ◽

Stimulation Of

The addition of 5-hydroxytryptamine to the isolated blowfly salivary gland stimulates fluid secretion, transepithelial calcium transport and the breakdown of 32P- or 3H-labelled phosphatidylinositol The breakdown of [32P]phosphatidylcholine and [32P]-phosphatidylethanolamine was not stimulated by 5-hydroxytryptamine. In salivary glands incubated with myo-[2-3H]inositol for 1–3 h, more than 95% of the label retained by the tissue was in the form of phosphatidylinositol. The addition of 5-hydroxytryptamine resulted in an increase in the accumulation of label in intracellular inositol 1:2-cyclic phosphate, inositol 1-phosphate and free inositol along with an increase in the release of [3H]inositol to the medium and saliva. The release of [3H]inositol to the medium served as a sensitive indicator of phosphatidylinositol breakdown. The release of [3H]inositol was not increased by cyclic AMP or the bivalent-cation ionophore A23187 under conditions in which salivary secretion was accelerated. The stimulation of fluid secretion by low concentrations of 5-hydroxytryptamine was potentiated by 3-isobutyl-1-methylxanthine, which had no effect on inositol release. The stimulation of fluid secretion by 5-hydroxytryptamine was greatly reduced in calcium-free buffer, but the breakdown of phosphatidylinositol continued at the same rate in the absence of calcium. These results support the hypothesis that breakdown of phosphatidylinositol by 5-hydroxytryptamine is involved in the gating of calcium.

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Effect of halothane on intracellular calcium oscillations in porcine tracheal smooth muscle cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1999.276.1.l81 ◽

1999 ◽

Vol 276 (1) ◽

pp. L81-L89 ◽

Cited By ~ 5

Author(s):

Christina M. Pabelick ◽

Y. S. Prakash ◽

Mathur S. Kannan ◽

Keith A. Jones ◽

David O. Warner ◽

...

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Ryanodine Receptor ◽

Muscle Cells ◽

Calcium Oscillations ◽

Tracheal Smooth Muscle ◽

Permeabilized Cells ◽

Inositol 1,4,5 Trisphosphate ◽

Intracellular Ca ◽

Trisphosphate Receptor

The effect of halothane on intracellular Ca2+ concentration ([Ca2+]i) regulation in porcine tracheal smooth muscle cells was examined with real-time confocal microscopy. Both 1 and 2 minimum alveolar concentration (MAC) halothane increased basal [Ca2+]iwhen Ca2+ influx and efflux were blocked, suggesting increased sarcoplasmic reticulum (SR) Ca2+ leak and/or decreased reuptake. In β-escin-permeabilized cells, heparin inhibition of inositol 1,4,5-trisphosphate-receptor channels blunted the halothane-induced increase in [Ca2+]i. Both 1 and 2 MAC halothane decreased the frequency and amplitude of ACh-induced [Ca2+]ioscillations (which represent SR Ca2+ release through ryanodine-receptor channels), abolishing oscillations in ∼20% of tracheal smooth muscle cells at 2 MAC. When Ca2+ influx and efflux were blocked, halothane increased the baseline and decreased the frequency and amplitude of [Ca2+]ioscillations, inhibiting oscillations in ∼70% of cells at 2 MAC. The fall time of [Ca2+]ioscillations and the rate of fall of the [Ca2+]iresponse to caffeine were both increased by halothane. These results suggest that halothane abolishes agonist-induced [Ca2+]ioscillations by 1) depleting SR Ca2+ via increased Ca2+ leak through inositol 1,4,5-trisphosphate-receptor channels, 2) decreasing Ca2+ release through ryanodine-receptor channels, and 3) inhibiting reuptake.

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Extraocular muscle function is impaired in ryr3−/− mice

The Journal of General Physiology ◽

10.1085/jgp.201912333 ◽

2019 ◽

Vol 151 (7) ◽

pp. 929-943 ◽

Cited By ~ 4

Author(s):

Jan Eckhardt ◽

Christoph Bachmann ◽

Marijana Sekulic-Jablanovic ◽

Volker Enzmann ◽

Ki Ho Park ◽

...

Keyword(s):

Muscle Contraction ◽

Ryanodine Receptor ◽

Muscle Function ◽

Extraocular Muscle ◽

Calcium Release ◽

Neuronal Excitability ◽

Extraocular Muscles ◽

Inositol Trisphosphate Receptor ◽

Physiological Processes ◽

Trisphosphate Receptor

Calcium is an ubiquitous second messenger mediating numerous physiological processes, including muscle contraction and neuronal excitability. Ca2+ is stored in the ER/SR and is released into the cytoplasm via the opening of intracellular inositol trisphosphate receptor and ryanodine receptor calcium channels. Whereas in skeletal muscle, isoform 1 of the RYR is the main channel mediating calcium release from the SR leading to muscle contraction, the function of ubiquitously expressed ryanodine receptor 3 (RYR3) is far from clear; it is not known whether RYR3 plays a role in excitation–contraction coupling. We recently reported that human extraocular muscles express high levels of RYR3, suggesting that such muscles may be useful to study the function of this isoform of the Ca2+ channel. In the present investigation, we characterize the visual function of ryr3−/− mice. We observe that ablation of RYR3 affects both mechanical properties and calcium homeostasis in extraocular muscles. These changes significantly impact vision. Our results reveal for the first time an important role for RYR3 in extraocular muscle function.

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