The calcium-sensing receptor regulates calcium absorption in MDCK cells by inhibition of PMCA

Calcium transport across a monolayer of Madin-Darby canine kidney (MDCK) cells was measured in response to stimulation of the basal surface with calcium-sensing receptor (CaR) agonists. Stimulation of the CaR resulted in a time- and concentration-dependent inhibition of calcium transport but did not change transepithelial voltage or resistance. Inhibition of transport was not altered by pretreatment of cells with pertussis toxin but was blocked by the phospholipase C (PLC) inhibitor U-73122. To determine a potential mechanism by which the CaR could inhibit calcium transport, we measured activity of the plasma membrane calcium ATPase (PMCA). Stimulation of the CaR on the basal surface resulted in an inhibition of the PMCA in a concentration- and PLC-dependent manner. Thus stimulation of the CaR inhibits both calcium transport and PMCA activity through a PLC-dependent pathway. These studies provide the first direct evidence that calcium can inhibit its own transcellular absorption in a model of the distal tubule. In addition, they provide a potential mechanism for the CaR to inhibit calcium transport, inhibition of PMCA.

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The calcium-sensing receptor regulates PTHrP production and calcium transport in the lactating mammary gland

Bone ◽

10.1016/j.bone.2005.11.009 ◽

2006 ◽

Vol 38 (6) ◽

pp. 787-793 ◽

Cited By ~ 53

Author(s):

Laleh Ardeshirpour ◽

Pamela Dann ◽

Martin Pollak ◽

John Wysolmerski ◽

Joshua VanHouten

Keyword(s):

Mammary Gland ◽

Calcium Transport ◽

Calcium Sensing Receptor ◽

Calcium Sensing ◽

Lactating Mammary Gland

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Calcium-Sensing Receptor Stimulation in Cultured Glomerular Podocytes Induces TRPC6-Dependent Calcium Entry and RhoA Activation

Cellular Physiology and Biochemistry ◽

10.1159/000484064 ◽

2017 ◽

Vol 43 (5) ◽

pp. 1777-1789 ◽

Cited By ~ 7

Author(s):

Lei Zhang ◽

Tianrong Ji ◽

Qin Wang ◽

Kexin Meng ◽

Rui Zhang ◽

...

Keyword(s):

Protective Action ◽

Focal Adhesions ◽

Stress Fiber ◽

Fiber Formation ◽

Stress Fibers ◽

Dependent Manner ◽

Calcium Sensing Receptor ◽

Rhoa Activity ◽

Rhoa Activation ◽

Calcium Sensing

Background/Aims: Recent studies provided compelling evidence that stimulation of the calcium sensing receptor (CaSR) exerts direct renoprotective action at the glomerular podocyte level. This protective action may be attributed to the RhoA-dependent stabilization of the actin cytoskeleton. However, the underlying mechanisms remain unclear. Methods: In the present study, an immortalized human podocyte cell line was used. Fluo-3 fluorescence was utilized to determine intracellular Ca2+ concentration ([Ca2+]i), and western blotting was used to measure canonical transient receptor potential 6 (TRPC6) protein expression and RhoA activity. Stress fibers were detected by FITC-phalloidin. Results: Activating CaSR with a high extracellular Ca2+ concentration ([Ca2+]o) or R-568 (a type II CaSR agonist) induces an increase in the [Ca2+]i in a dose-dependent manner. This increase in [Ca2+]i is phospholipase C (PLC)-dependent and is smaller in the absence of extracellular Ca2+ than in the presence of 0.5 mM [Ca2+]o. The CaSR activation-induced [Ca2+]i increase is attenuated by the pharmacological blockage of TRPC6 channels or siRNA targeting TRPC6. These data suggest that TRPC6 is involved in CaSR activation-induced Ca2+ influx. Consistent with a previous study, CaSR stimulation results in an increase in RhoA activity. However, the knockdown of TRPC6 significantly abolished the RhoA activity increase induced by CaSR stimulation, suggesting that TRPC6-dependent Ca2+ entry is required for RhoA activation. The activated RhoA is involved in the formation of stress fibers and focal adhesions in response to CaSR stimulation because siRNA targeting RhoA attenuated the increase in the stress fiber mediated by CaSR stimulation. Moreover, this effect of CaSR activation on the formation of stress fibers is also abolished by the knockdown of TRPC6. Conclusion: TRPC6 is involved in the regulation of stress fiber formation and focal adhesions via the RhoA pathway in response to CaSR activation. This may explain the direct protective action of CaSR agonists.

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Calcium-dependent phosphodiesterase 1C inhibits renin release from isolated juxtaglomerular cells

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00121.2009 ◽

2009 ◽

Vol 297 (5) ◽

pp. R1469-R1476 ◽

Cited By ~ 27

Author(s):

M. Cecilia Ortiz-Capisano ◽

Tang-Dong Liao ◽

Pablo A. Ortiz ◽

William H. Beierwaltes

Keyword(s):

Western Blot ◽

Blot Analysis ◽

Western Blot Analysis ◽

Renin Release ◽

Calcium Sensing Receptor ◽

Calcium Dependent ◽

Calcium Sensing ◽

Inhibitory Modulation ◽

Camp Formation ◽

Stimulation Of

Renin release from the juxtaglomerular (JG) cell is stimulated by the second messenger cAMP and inhibited by calcium. We previously showed JG cells contain a calcium sensing receptor (CaSR), which, when stimulated, decreases cAMP formation and inhibits renin release. We hypothesize CaSR activation decreases cAMP and renin release, in part, by stimulating a calcium calmodulin-activated phosphodiesterase 1 (PDE1). We incubated our primary culture of JG cells with two selective PDE1 inhibitors [8-methoxymethil-IBMX (8-MM-IBMX; 20 μM) and vinpocetine (40 μM)] and the calmodulin inhibitor W-7 (10 μM) and measured cAMP and renin release. Stimulation of the JG cell CaSR with the calcimimetic cinacalcet (1 μM) resulted in decreased cAMP from a basal of 1.13 ± 0.14 to 0.69 ± 0.08 pM/mg protein ( P < 0.001) and in renin release from 0.89 ± 0.16 to 0.38 ± 0.08 μg ANG I/ml·h−1·mg protein−1 ( P < 0.001). However, the addition of 8-MM-IBMX with cinacalcet returned both cAMP (1.10 ± 0.19 pM/mg protein) and renin (0.57 ± 0.16 μg ANG I/ml·h−1·mg protein−1) to basal levels. Similar results were obtained with vinpocetine, and also with W-7. Combining 8-MM-IBMX and W-7 had no additive effect. To determine which PDE1 isoform is involved, we performed Western blot analysis for PDE1A, B, and C. Only Western blot analysis for PDE1C showed a characteristic band apparent at 80 kDa. Immunofluorescence showed cytoplasmic distribution of PDE1C and renin in the JG cells. In conclusion, PDE1C is expressed in isolated JG cells, and contributes to calcium's inhibitory modulation of renin release from JG cells.

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The Calcium-Sensing Receptor Regulates Plasma Membrane Calcium Adenosine Triphosphatase Isoform 2 Activity in Mammary Epithelial Cells: A Mechanism for Calcium-Regulated Calcium Transport into Milk

Endocrinology ◽

10.1210/en.2007-0850 ◽

2007 ◽

Vol 148 (12) ◽

pp. 5943-5954 ◽

Cited By ~ 63

Author(s):

Joshua N. VanHouten ◽

Margaret C. Neville ◽

John J. Wysolmerski

Keyword(s):

Plasma Membrane ◽

Epithelial Cells ◽

Calcium Transport ◽

Adenosine Triphosphatase ◽

Mammary Epithelial Cells ◽

Mammary Epithelial ◽

Calcium Sensing Receptor ◽

Calcium Sensing ◽

Calcium Adenosine Triphosphatase

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Activation of the calcium-sensing receptor attenuates TRPV6-dependent intestinal calcium absorption

JCI Insight ◽

10.1172/jci.insight.128013 ◽

2019 ◽

Vol 4 (11) ◽

Cited By ~ 2

Author(s):

Justin J. Lee ◽

Xiong Liu ◽

Debbie O’Neill ◽

Megan R. Beggs ◽

Petra Weissgerber ◽

...

Keyword(s):

Calcium Absorption ◽

Intestinal Calcium Absorption ◽

Calcium Sensing Receptor ◽

Calcium Sensing

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Basolateral Calcium Sensing Receptor Mediated Regulation of TRPV6‐dependent Transcellular Calcium Absorption

The FASEB Journal ◽

10.1096/fasebj.2019.33.1_supplement.575.17 ◽

2019 ◽

Vol 33 (S1) ◽

Author(s):

Justin Lee ◽

Xiong Liu ◽

Debbie O'Neill ◽

Megan R Beggs ◽

Petra Weissgerber ◽

...

Keyword(s):

Calcium Absorption ◽

Calcium Sensing Receptor ◽

Calcium Sensing

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Emerging roles of calcium-sensing receptor in the local regulation of intestinal transport of ions and calcium

AJP Cell Physiology ◽

10.1152/ajpcell.00485.2020 ◽

2020 ◽

Author(s):

Krittikan Chanpaisaeng ◽

Jarinthorn Teerapornpuntakit ◽

Kannikar Wongdee ◽

Narattaphol Charoenphandhu

Keyword(s):

Transient Receptor Potential ◽

Calcium Absorption ◽

Intestinal Transport ◽

Receptor Potential ◽

Negative Control ◽

Paracrine Factor ◽

Calcium Sensing Receptor ◽

Calcium Sensing ◽

Fgf 23 ◽

Feedback Responses

Whether the intestinal mucosal cells are capable of sensing calcium concentration in the lumen and pericellular interstitium remains enigmatic for decades. Most calcium-regulating organs, such as parathyroid gland, kidney and bone, are capable of using calcium-sensing receptor (CaSR) to detect plasma calcium and trigger appropriate feedback responses to maintain calcium homeostasis. Although both CaSR transcripts and proteins are abundantly expressed in the crypt and villous enterocytes of the small intestine as well as the surface epithelial cells of the large intestine, the studies of CaSR functions have been limited to amino acid sensing and regulation of epithelial fluid secretion. Interestingly, several lines of recent evidence have indicated that the enterocytes use CaSR to monitor luminal and extracellular calcium levels, thereby reducing the activity of transient receptor potential channel, subfamily V, member 6, and inducing paracrine and endocrine feedback responses to restrict calcium absorption. Recent investigations in zebra fish and rodents have also suggested the role of fibroblast growth factor (FGF)-23 as an endocrine and/or paracrine factor participating in the negative control of intestinal calcium transport. In this review article, besides the CaSR-modulated ion transport, we elaborate the possible roles of CaSR and FGF-23 as well as their crosstalk as parts of a negative feedback loop for counterbalancing the seemingly unopposed calciotropic effect of 1,25-dihydroxyvitamin D3 on the intestinal calcium absorption.

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Transcriptional Response to Calcium-Sensing Receptor Stimulation

Endocrinology ◽

10.1210/en.2012-1343 ◽

2012 ◽

Vol 153 (10) ◽

pp. 4716-4728 ◽

Cited By ~ 35

Author(s):

Gerald Thiel ◽

Andrea Lesch ◽

Anja Keim

Keyword(s):

Gene Transcription ◽

Ternary Complex ◽

Dominant Negative ◽

Signaling Cascade ◽

Dominant Negative Mutant ◽

Calcium Sensing Receptor ◽

Receptor Stimulation ◽

Calcium Sensing ◽

Negative Mutant ◽

Stimulation Of

Abstract Elevated extracellular Ca2+ concentrations stimulate the G-protein coupled receptor calcium-sensing receptor. Here we show that this stimulation induces the expression of biologically active early growth response protein 1 (Egr-1), a zinc finger transcription factor. Expression of a dominant-negative mutant of the ternary complex factor Ets-like protein-1 (Elk-1), a key transcriptional regulator of serum response element-driven gene transcription, prevented Egr-1 expression, indicating that Elk-1 or related ternary complex factors connect the intracellular signaling cascade elicited by activation of calcium-sensing receptors with transcription of the Egr-1 gene. These data were corroborated by the fact that stimulation of calcium-sensing receptors increased the transcriptional activation potential of Elk-1. In addition, activator protein-1 (AP-1) transcriptional activity was significantly elevated after the stimulation of calcium-sensing receptors. The expression of a dominant-negative mutant of Elk-1 reduced c-Fos expression and prevented the up-regulation of AP-1 activity as a result of calcium-sensing receptor stimulation, indicating that ternary complex factors control both Egr-1- and AP-1-regulated transcription. In addition, AP-1 activity was reduced after the expression of a dominant-negative mutant of c-Jun in cells expressing an activated calcium-sensing receptor. Stimulus-transcription coupling leading to the up-regulation of Egr-1 and AP-1 controlled transcription in cells expressing calcium-sensing receptors required the protein kinases Raf and ERK, whereas the overexpression of MAPK phosphatase-1 interrupted the signaling cascade connecting calcium-sensing receptor stimulation with transcription of Egr-1 and AP-1 controlled genes. The fact that calcium-sensing receptor stimulation activates the transcription factors Egr-1, Elk-1, and AP-1 indicates that regulation of gene transcription is an integral part of calcium-sensing receptor induced signaling.

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