Previous studies have demonstrated a gain-of-function of the calcium-sensing receptor (CASR) gene R990G polymorphism. In this study, activation of the R990G CASR stably transfected in HEK-293 (HEK-990G) cells compared with that of the common variant (HEK-wild-type (WT)) by increasing concentrations of CaCl2 or calcimimetic R-568 caused significantly higher intracellular free calcium concentration ([Ca2+]i) and lower Ca-EC50. Moreover, the [Ca2+]i oscillation percentage was higher with a larger sinusoidal pattern in HEK-990G. R-568 induced a shift of the oscillatory events from 4 to 2 mmol/l extracellular calcium concentration in HEK-990G cells and increased the sinusoidal oscillation percentage in comparison with HEK-WT. Preincubation with thapsigargin or phospholipase C inhibitors completely prevented oscillations in both cell lines, consistent with the involvement of the inositol trisphosphate pathway, while protein kinase C inhibitor prevented oscillations in HEK-WT cells only. Finally, CaCl2 and R-568 caused a significant increase in p44/42 extracellular signaling-regulated kinase phosphorylation, with the mean Ca-EC50 values being significantly lower in HEK-990G. Our findings demonstrated that the 990G allele is associated with high sensitivity to R-568, which provided new evidence for differences in CASR signaling.

Calcimimetic R-568 effects on activity of R990G polymorphism of calcium-sensing receptor / A. Terranegra, A. Ferraretto, E. Dogliotti, M. Scarpellini, S.L. Corbetta, A.M. Barbieri, A. Spada, T. Arcidiacono, F. Rainone, A. Aloia, D.M. Cusi, G. Vezzoli, L. Soldati. - In: JOURNAL OF MOLECULAR ENDOCRINOLOGY. - ISSN 0952-5041. - 45:4(2010 Oct), pp. 245-246.

Calcimimetic R-568 effects on activity of R990G polymorphism of calcium-sensing receptor

A. Terranegra;A. Ferraretto;E. Dogliotti;S.L. Corbetta;A.M. Barbieri;A. Spada;A. Aloia;D.M. Cusi;G. Vezzoli;L. Soldati
2010

Abstract

Previous studies have demonstrated a gain-of-function of the calcium-sensing receptor (CASR) gene R990G polymorphism. In this study, activation of the R990G CASR stably transfected in HEK-293 (HEK-990G) cells compared with that of the common variant (HEK-wild-type (WT)) by increasing concentrations of CaCl2 or calcimimetic R-568 caused significantly higher intracellular free calcium concentration ([Ca2+]i) and lower Ca-EC50. Moreover, the [Ca2+]i oscillation percentage was higher with a larger sinusoidal pattern in HEK-990G. R-568 induced a shift of the oscillatory events from 4 to 2 mmol/l extracellular calcium concentration in HEK-990G cells and increased the sinusoidal oscillation percentage in comparison with HEK-WT. Preincubation with thapsigargin or phospholipase C inhibitors completely prevented oscillations in both cell lines, consistent with the involvement of the inositol trisphosphate pathway, while protein kinase C inhibitor prevented oscillations in HEK-WT cells only. Finally, CaCl2 and R-568 caused a significant increase in p44/42 extracellular signaling-regulated kinase phosphorylation, with the mean Ca-EC50 values being significantly lower in HEK-990G. Our findings demonstrated that the 990G allele is associated with high sensitivity to R-568, which provided new evidence for differences in CASR signaling.
Settore MED/14 - Nefrologia
ott-2010
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/148221
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