Expression of TRPC homologs in endothelial cells and smooth muscle layers of human arteries

Abstract

TRPC channels are a group of Ca(2+)-permeable nonselective cation channels that mediate store-operated and/or agonist-stimulated Ca(2+) influx in a variety of cell types. In this study, we extensively examined the expression patterns of TRPC homologs in human vascular tissues. RT-PCR amplified cDNA fragments of TRPC1 (505 bp), TRPC3 (372 bp), TRPC4 (499 bp), TRPC5 (325 bp), TRPC6 (509 bp), and TRPC7 (187 bp) from RNA isolated from cultured human coronary artery endothelial cells. In situ hybridization yielded strong labeling of TRPC1,3-6 in the endothelial and smooth muscle cells of human coronary and cerebral arteries. TRPC7 labeling was exclusively found in endothelial cells but not in smooth muscle cells. Results from immunohistochemical staining were consistent with those from in situ hybridization. Similar expression patterns of TRPC homologs were also observed in arterioles and vaso vasora. In conclusion, our study indicates that TRPC homologs are widely expressed in human vessels of all calibers, including medium-sized coronary arteries and cerebral arteries, smaller-sized resistance arteries, and vaso vasora. These results suggest a ubiquitous role of TRPC homologs in regulating blood supply to different regions and in controlling arterial blood pressure.

Effects of Serum Amyloid A and Lysophosphatidylcholine on Intracellular Calcium Concentration in Human Coronary Artery Smooth Muscle Cells

“…43) However, the molecular identities and function of TRP channels remain largely unexplored in hCASMCs, and only a few studies have examined the expression of TRPC channels. To date, 7 TRPC subtypes have been identified: TRPC1 to TRPC7, and classified into 4 subgroups based on their amino acid sequences: TRPC1, TRPC3/6/7, and TRPC4/5.…”

Angiotensin II-stimulated Ca2+ entry mechanisms in afferent arterioles: role of transient receptor potential canonical channels and reverse Na+/Ca2+ exchange

“…Thus agonist stimulation of G protein-coupled receptors in VSMC that result in formation of phospholipase C (PLC) can initiate formation not only of IP 3 -mediated Ca 2ϩ signaling events but also DAG activation of this group of TRPC. TRPC6 and often TRPC3 have been shown to be present in some large arteries (coronary, aorta, main renal artery) (11,24,53,55) and in some A7r5 cell lines (38). TRPC3 may be the predominant subtype in endothelial cells (44,55), whereas small arteries and arterioles appear to contain largely TPRC6 (54).…”

“…TRPC6 and often TRPC3 have been shown to be present in some large arteries (coronary, aorta, main renal artery) (11,24,53,55) and in some A7r5 cell lines (38). TRPC3 may be the predominant subtype in endothelial cells (44,55), whereas small arteries and arterioles appear to contain largely TPRC6 (54). Preglomerular VSMC have six to eight times more TRPC 6 protein than aortic VSMC (11).…”

Elucidation of a TRPC6-TRPC5 Channel Cascade That Restricts Endothelial Cell Movement

“…TRPC1, TRPC4, and TRPC5 have been characterized as store-dependent channels and TRPC3, TRPC6, and TRPC7 as store-independent channels, but at least TRPC3, TRPC5, and TRPC7 are recognized to function as both receptor-and store-operated channels (Nilius and Droogmans, 2003;Lièvremont et al, 2004;Zeng et al, 2004). Although all TRPC channels are expressed in EC (Yip et al, 2004), expression varies in different vascular beds (Yao and Garland, 2005), and this may influence EC function.…”

“…LysoPC activated TRPC5 channels in HEK cells overexpressing TRPC5 (Flemming et al, 2006) and increased [Ca 2ϩ ] i in smooth muscle cells that have endogenous TRPC6 channels (So et al, 2005). Because TRPC5 and TRPC6 are expressed in bovine ECs (Yip et al, 2004) and can be store-independent (Nilius and Droogmans, 2003;Zeng et al, 2004) and because TRPC6 plays a role in vascular endothelial growth factor-mediated microvessel permeability and thrombin-induced EC shape change (Pocock et al, 2004;Singh et al, 2007), we explored This article was published online ahead of print in MBC in Press (http://www.molbiolcell.org/cgi/doi/10.1091/mbc.E07-08 -0765) on May 21, 2008. the role of TRPC5 and TRPC6 in lysoPC-induced calcium influx and subsequent inhibition of EC migration.…”