Referenced in: none

Automatically associated channels: TRP , TRPC , TRPC1 , TRPC6

Title: TRPC6 regulates cell cycle progression by modulating membrane potential in bone marrow stromal cells.

Authors: Jun Ichikawa, Ryuji Inoue

Journal, date & volume: Br. J. Pharmacol., 2014 Dec , 171, 5280-94

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/25041367

Abstract
Ca(2+) influx is important for cell cycle progression, but the mechanisms involved seem to vary. We investigated the potential roles of transient receptor potential (TRP) channels and store-operated Ca(2+) entry (SOCE)-related molecules STIM (stromal interaction molecule)/Orai in the cell cycle progression of rat bone marrow stromal cells (BMSCs), a reliable therapeutic resource for regenerative medicine.PCR and immunoblot analyses were used to examine mRNA and protein levels, fluorescence imaging and patch clamping for Ca(2+) influx and membrane potential measurements, and flow cytometry for cell cycle analysis.Cell cycle synchronization of BMSCs revealed S phase-specific enhancement of TRPC1, STIM and Orai mRNA and protein expression. In contrast, TRPC6 expression decreased in the S phase and increased in the G1 phase. Resting membrane potential (RMP) of BMSCs was most negative and positive in the S and G1 phases, respectively, and was accompanied by an enhancement and attenuation of SOCE respectively. Chemically depolarizing/hyperpolarizing the membrane erased these differences in SOCE magnitude during the cell cycle. siRNA knockdown of TRPC6 produced a negative shift in RMP, increased SOCE and caused redistribution of BMSCs with increased populations in the S and G2 /M phases and accumulation of cyclins A2 and B1. A low concentration of Gd(3+) (1 μM) suppressed BMSC proliferation at its concentration to inhibit SOC channels relatively specifically.TRPC6, by changing the membrane potential, plays a pivotal role in controlling the SOCE magnitude, which is critical for cell cycle progression of BMSCs. This finding provides a new therapeutic strategy for regulating BMSC proliferation.