Open AccessExpression and function of mechanosensitive ion channels in human valve interstitial cells
Author(s) -
Hessah Alshammari,
Najma Latif,
Padmini Sarathchandra,
A Mccormack,
Eva A. Rog-Zielinska,
Shahzad G. Raja,
Peter Kohl,
Magdi H. Yacoub,
Rémi Peyronnet,
Adrian H. Chester
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0240532
Subject(s) - mechanosensitive channels , mechanotransduction , trpv4 , trpc6 , microbiology and biotechnology , ion channel , chemistry , potassium channel , interstitial cell , phenotype , biology , anatomy , transient receptor potential channel , biophysics , endocrinology , biochemistry , gene , receptor
Background The ability of heart valve cells to respond to their mechanical environment represents a key mechanism by which the integrity and function of valve cusps is maintained. A number of different mechanotransduction pathways have been implicated in the response of valve cells to mechanical stimulation. In this study, we explore the expression pattern of several mechanosensitive ion channels (MSC) and their potential to mediate mechanosensitive responses of human valve interstitial cells (VIC). Methods MSC presence and function were probed using the patch clamp technique. Protein abundance of key MSC was evaluated by Western blotting in isolated fibroblastic VIC (VIC FB ) and in VIC differentiated towards myofibroblastic (VIC MB ) or osteoblastic (VIC OB ) phenotypes. Expression was compared in non-calcified and calcified human aortic valves. MSC contributions to stretch-induced collagen gene expression and to VIC migration were assessed by pharmacological inhibition of specific channels. Results Two MSC types were recorded in VIC FB : potassium selective and cation non-selective channels. In keeping with functional data, the presence of both TREK-1 and Kir6.1 (potassium selective), as well as TRPM4, TRPV4 and TRPC6 (cationic non-selective) channels was confirmed in VIC at the protein level. Differentiation of VIC FB into VIC MB or VIC OB phenotypes was associated with a lower expression of TREK-1 and Kir6.1, and a higher expression of TRPV4 and TRPC6. Differences in MSC expression were also seen in non-calcified vs calcified aortic valves where TREK-1, TRPM4 and TRPV4 expression were higher in calcified compared to control tissues. Cyclic stretch-induced expression of COL I mRNA in cultured VIC FB was blocked by RN-9893, a selective inhibitor of TRPV4 channels while having no effect on the stretch-induced expression of COL III. VIC FB migration was blocked with the non-specific MSC blocker streptomycin and by GSK417651A an inhibitor of TRPC6/3. Conclusion Aortic VIC express a range of MSC that play a role in functional responses of these cells to mechanical stimulation. MSC expression levels differ in calcified and non-calcified valves in ways that are in part compatible with the change in expression seen between VIC phenotypes. These changes in MSC expression, and associated alterations in the ability of VIC to respond to their mechanical environment, may form novel targets for intervention during aortic valvulopathies.