Pulsatile Atheroprone Shear Stress Affects the Expression of Transient Receptor Potential Channels in Human Endothelial Cells
Department of Nephrology, Charité Campus Benjamin Franklin, Berlin, Germany.Hypertension (Impact Factor: 6.48). 05/2012; 59(6):1232-40. DOI: 10.1161/HYPERTENSIONAHA.111.183608
The goal of the study was to assess whether pulsatile atheroprone shear stress modulates the expression of transient receptor potential (TRP) channels, TRPC3, TRPC6, TRPM7, and TRPV1 mRNA, in human umbilical vascular endothelial cells. Exposure of cultured vascular endothelial cells to defined shear stress, producing a constant laminar flow (generating a shear stress of 6 dyne/cm(2)), laminar pulsatile atheroprotective flow (with a mean shear stress of 20 dyne/cm(2)), or laminar atheroprone bidirectional flow (with a mean shear stress of 0 dyne/cm(2)) differentially induced TRPC6 and TRPV1 mRNA as measured by quantitative real-time RT-PCR and normalized to GAPDH expression. Thereby, TRPC6 and TRPV1 mRNA expressions were significantly increased after 24 hours of exposure to an atheroprone flow profile compared with an atheroprotective flow profile. Furthermore, the expression of transcription factors GATA1 and GATA4 was significantly correlated with the expression of TRPC6 mRNA. In contrast, after 24 hours of constant laminar flow, the expression of TRPC6 and TRPV1 mRNA was unchanged, whereas the expression of TRPC3 and TRPM7 was significantly higher in endothelial cells exposed to shear stress in comparison with endothelial cells grown under static conditions. There was a significant association between the expression of TRPC6 and tumor necrosis factor-α mRNA in human vascular tissue. No-flow and atheroprone flow conditions are equally characterized by an increase in the expression of tumor necrosis factor-α; however, inflammation-associated endothelial cell reactions may be further aggravated at atheroprone flow conditions by the increase of TRPV1 and TRPC6, as observed in our study.
[Show abstract] [Hide abstract]
- "However, this report is the only one demonstrating the existence of TRPC5/6 heteromeric channels, while other studies excluded this sort of heteromultimerisation (see above and Hofmann et al. 2002; Goel et al. 2002; Strubing et al. 2003). Very recently, it was reported that atheroprone shear stress induced TRPC6 and TRPV1 mRNA expression in endothelial cells, but a putative role of TRPC6 in atherosclerosis remains elusive (Thilo et al. 2012). Smooth muscle cells provide not only structural integrity for the vessel but also precise regulation of vascular tone and blood pressure. "
ABSTRACT: TRPC6 is a non-selective cation channel 6 times more permeable to Ca(2+) than to Na(+). Channel homotetramers heterologously expressed have a characteristic doubly rectifying current-voltage relationship and are directly activated by the second messenger diacylglycerol (DAG). TRPC6 proteins are also regulated by specific tyrosine or serine phosphorylation and phosphoinositides. Given its specific expression pattern, TRPC6 is likely to play a number of physiological roles which are confirmed by the analysis of a Trpc6 (-/-) mouse model. In smooth muscle Na(+) influx through TRPC6 channels and activation of voltage-gated Ca(2+) channels by membrane depolarisation is the driving force for contraction. Permeability of pulmonary endothelial cells depends on TRPC6 and induces ischaemia-reperfusion oedema formation in the lungs. TRPC6 was also identified as an essential component of the slit diaphragm architecture of kidney podocytes and plays an important role in the protection of neurons after cerebral ischaemia. Other functions especially in immune and blood cells remain elusive. Recently identified TRPC6 blockers may be helpful for therapeutic approaches in diseases with highly activated TRPC6 channel activity.Handbook of experimental pharmacology 04/2014; 222:157-88. DOI:10.1007/978-3-642-54215-2_7
[Show abstract] [Hide abstract]
- "In endothelial cells derived from the umbilical vein (HUVEC), two independent reports have shown that siRNAs transiently silencing TRPM7 stimulate cell proliferation , , a behaviour which is unique to HUVEC, because in various cell types silencing TRPM7 induces cell cycle arrest. In addition to the significant elevation of TRPM7 in the vasculature of MgL mice , the increase of TRPM7 transcript in HUVEC exposed to shear stress has been described . "
ABSTRACT: TRPM7, a cation channel of the transient receptor potential channel family, has been identified as a ubiquitous magnesium transporter. We here show that TRPM7 is expressed in endothelial cells isolated from the umbilical vein (HUVEC), widely used as a model of macrovascular endothelium. Quiescence and senescence do not modulate TRPM7 amounts, whereas oxidative stress generated by the addition of hydrogen peroxide increases TRPM7 levels. Moreover, high extracellular magnesium decreases the levels of TRPM7 by activating calpains, while low extracellular magnesium, known to promote endothelial dysfunction, stimulates TRPM7 accumulation partly through the action of free radicals. Indeed, the antioxidant trolox prevents TRPM7 increase by low magnesium. We also demonstrate the unique behaviour of HUVEC in responding to pharmacological and genetic inhibition of TRPM7 with an increase of cell growth and migration. Our results indicate that TRPM7 modulates endothelial behavior and that any condition leading to TRPM7 upregulation might impair endothelial function.PLoS ONE 03/2013; 8(3):e59891. DOI:10.1371/journal.pone.0059891 · 3.23 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Purpose of review: The involvement of neurohormonal factors in the pathogenesis of hypertension has been extensively studied. However, the mechanisms underlying the role of the transient receptor potential vanilloid type 1 (TRPV1) channels in hypertension are still largely unknown. This review presents some of the most recent findings regarding the potential mechanisms of TRPV1 in mediating blood pressure, the pathophysiology of hypertension, and its related disorders. Recent findings: TRPV1 may be activated by exogenous vanilloid or endo-vanilloid compounds and its function modulated by vasoactive mediators. TRPV1 also interacts with various physiological and pathophysiological systems involved in salt and water homeostasis and cardiovascular homeostasis. Impairment of TRPV1 signaling may contribute to the pathogenesis of diseases such as hypertension, heart failure, atherosclerosis, diabetes, obesity, myocardial ischemia, and stroke. Summary: Accumulating evidence implicates TRPV1 as serving a key role in cardiovascular health by regulating cardiovascular function and protecting against cardiovascular injury. Given the large prevalence of hypertension and its related disorders, the possible involvement of TRPV1 makes it a potential target of therapy for cardiovascular disease. Future study of TRPV1 may enhance our understanding of several cardiovascular diseases and may unveil novel pharmacological strategies for treating hypertension.Current opinion in nephrology and hypertension 12/2012; 22(2). DOI:10.1097/MNH.0b013e32835c8d4c · 3.96 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.