Store-operated calcium entry promotes shape change in pulmonary endothelial cells expressing Trp1

Abstract

Activation of Ca2+ entry is known to produce endothelial cell shape change, leading to increased permeability, leukocyte migration, and initiation of angiogenesis in conduit-vessel endothelial cells. The mode of Ca2+ entry regulating cell shape is unknown. We hypothesized that activation of store-operated Ca2+ channels (SOCs) is sufficient to promote cell shape change necessary for these processes. SOC activation in rat pulmonary arterial endothelial cells increased free cytosolic Ca2+ that was dependent on a membrane current having a net inward component of 5.45 ± 0.90 pA/pF at −80 mV. Changes in endothelial cell shape accompanied SOC activation and were dependent on Ca2+ entry-induced reconfiguration of peripheral (cortical) filamentous actin (F-actin). Because the identity of pulmonary endothelial SOCs is unknown, but mammalian homologues of the Drosophila melanogaster transient receptor potential ( trp) gene have been proposed to form Ca2+ entry channels in nonexcitable cells, we performed RT-PCR using Trp oligonucleotide primers in both rat and human pulmonary arterial endothelial cells. Both cell types were found to express Trp1, but neither expressed Trp3 nor Trp6. Our study indicates that 1) Ca2+ entry in pulmonary endothelial cells through SOCs produces cell shape change that is dependent on site-specific rearrangement of the microfilamentous cytoskeleton and 2) Trp1 may be a component of pulmonary endothelial SOCs.

Regulation of endothelial permeability by Src kinase signaling: Vascular leakage versus transcellular transport of drugs and macromolecules

“…The mechanism by which Src regulates Ca 2+ influx is unclear. Src may phosphorylate plasma membrane transient receptor potential channels expressed in endothelial cells [119,120] that mediate Ca 2+ influx during inositol trisphosphate-sensitive intracellular store depletion [121,122]. Thrombin increased the tyrosine phosphorylation of junctional proteins and the formation of interendothelial gaps that are characteristically associated with the loss of barrier function [2,11,66,67,123].…”

Mechanisms of leukotriene D4‐induced constriction in human small bronchioles

“…It is very probable that more than one type of TRP channel is expressed in ASM. Indeed, both TRP6 and TRP7 have been found in lung (Boulay et al, 1997;Moore et al, 1998;Okada et al, 1999), while TRP1 has been shown to regulate endothelial permeability in the pulmonary vasculature (Moore et al, 1998).…”

Glucose enhances expression of TRPC1 and calcium entry in endothelial cells

“…However, it has been previously argued that mammalian homologs of the transient receptor potential (TRP) gene family and notably the canonical TRPC subfamily of channels function as SOCs (43). Thus both TRPC1 and TRPC4 have been implicated in mediating SOCE in endothelial cells (23,34). Indeed, TRPC1 has been shown to colocalize with Orai1 and STIM1, and studies with exogenously expressed TRPC1 and STIM1 in endothelial cells indicate that TRPC1 is regulated by STIM1 (26,38).…”