Tumor necrosis factor-α-induced TRPC1 expression amplifies store-operated Ca²⁺influx and endothelial permeability

Abstract

influx in response to thrombin exposure. We observed that thrombininduced Ca 2ϩ influx in TNF-␣-stimulated HPAEC was twofold greater than in control cells. To address the relationship between store-operated Ca 2ϩ influx and TRPC1 expression, we overexpressed TRPC1 by three-to fourfold in the human dermal microvascular endothelial cell line (HMEC) using the TRPC1 cDNA. Thrombininduced store Ca 2ϩ depletion in these cells caused approximately twofold greater increase in Ca 2ϩ influx than in control cells. Furthermore, the inositol 1,4,5-trisphosphate-sensitive store-operated cationic current was increased greater than twofold in TRPC1-transfected cells compared with control. To address the role of Ca 2ϩ influx via TRPC1 in signaling endothelial permeability, we measured actinstress fiber formation and transendothelial monolayer electrical resistance (TER) in the TRPC1 cDNA-transfected HMEC and TNF-␣-challenged HPAEC. Both thrombin-induced actin-stress fiber formation and a decrease in TER were augmented in TRPC1-overexpressing HMEC compared with control cells. TNF-␣-induced increased TRPC1 expression in HPAEC also resulted in marked endothelial barrier dysfunction in response to thrombin. These findings indicate the expression level of TRPC1 in endothelial cells is a critical determinant of Ca 2ϩ influx and signaling of the increase in endothelial permeability.tumor necrosis factor-␣; store-operated calcium ion influx; transient receptor potential channel 1; endothelial barrier dysfunction MICROVASCULAR ENDOTHELIAL cells regulate the vessel wall permeability of solutes, liquid, and macromolecules and produce numerous autocrine and paracrine factors, such as NO, that modulate the contractility of the underlying vascular smooth muscle (4,5,21

Store-operated Ca2+ Entry (SOCE) Induced by Protease-activated Receptor-1 Mediates STIM1 Protein Phosphorylation to Inhibit SOCE in Endothelial Cells through AMP-activated Protein Kinase and p38β Mitogen-activated Protein Kinase

“…We have shown that SOCE induced by thrombin ligation of PAR-1 mediates vascular barrier dysfunction and amplifies the expression of inflammatory genes in endothelial cells (3,15,16,32,33). Recent studies have shown that STIM1 is crucial for the activation of SOCE in endothelial cells (3)(4)(5).…”

Update on vascular endothelial Ca2+signalling: A tale of ion channels, pumps and transporters

“…Moreover, TRPC1-gated Ca 2+ entry is capable of stimulating nuclear factor (NF)-κB via AMP-activated protein kinase and PKCδ, so that NF-κB may initiate the transcriptional programme involved in the host defense to inflammatory stimuli and in EC resistance to apoptosis [219,220] . NF-κB, in turn, increases TRPC1 expression in ΤΝF-α-stimulated cells, thus establishing a feed-forward loop that amplifies agonist-elicited SOCE and the increase in transendothelial permeability [221,222] . Similarly, AngII upregulates TRPC1 levels in an NF-κB-dependent manner in ECs [223] .…”

MUSCLE DAMAGE IN MDX (DYSTROPHIC) MICE: ROLE OF CALCIUM AND REACTIVE OXYGEN SPECIES

“…34 Since caveolin-1, which has a similar overall structure to caveolin-3, 35 is known to bind TRPC1 in smooth muscle cells 36 this could mean that by having increased caveolin-3 expression in dystrophic muscle, TRPC1 expression might also be greater.I nf act, there is a suggestion from Western blots that TRPC1 levels are increased in mdx muscle compared to wild-type, 28 although this point was not specifically raised by the authors of this paper.F urthermore, recent work from our laboratory has shown that TRPC1 levels are greater in cardiac muscle from old mdx mice compared to wild-type (Williams & Allen, unpublished observations). In relation to this idea, it has recently been shown in endothelial cells that TRPC1 expression can be increased by the proinflammatory cytokine, tumour necrosis factor (TNFα), 37 which is intriguing in light of the fact that the levels of TNFα are enhanced in mdx muscle. 38 Afi nal point of interest is that caveolin-3 interacts with β-dystroglycan, to which dystrophin normally binds, and is thought to compete with dystrophin for this binding site.…”