Stimulation of cardiac fibroblast Piezo1 channels opposes myofibroblast differentiation and induces IL-6 secretion via Ca2+-mediated p38 MAP kinase activation

Blythe, N. M.; Stylianidis, V.; Ludlow, M. J.; Gilbert, H. T.; Evans, E. L.; Cuthbertson, K.; Foster, R.; Swift, J.; Li, J.; Drinkhill, M. J.; van Nieuwenhoven, F. A.; Porter, K. E.; Beech, D. J.; Turner, N. A.

doi:10.1101/603456

bioRxiv · 10.1101/603456

Stimulation of cardiac fibroblast Piezo1 channels opposes myofibroblast differentiation and induces IL-6 secretion via Ca2+-mediated p38 MAP kinase activation

Blythe, N. M.·Stylianidis, V.·Ludlow, M. J.·Gilbert, H. T.·Evans, E. L.·Cuthbertson, K.·Foster, R.·Swift, J.·Li, J.·Drinkhill, M. J.·van Nieuwenhoven, F. A.·Porter, K. E.·Beech, D. J.·Turner, N. A.

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Abstract

Piezo1 is a mechanosensitive cation channel with widespread physiological importance; however its role in the heart is poorly understood. Cardiac fibroblasts are responsible for preserving the structural integrity of the myocardium and play a key role in regulating its repair and remodeling following stress or injury. We investigated expression and function of Piezo1 in cultured human and mouse cardiac fibroblasts. RT-PCR studies confirmed expression of Piezo1 mRNA in cardiac fibroblasts at similar levels to endothelial cells. Fura-2 intracellular Ca2+ measurements validated Piezo1 as a functional ion channel that was activated by the Piezo1 agonist, Yoda1. Yoda1-induced Ca2+ entry was inhibited by Piezo1 blockers (gadolinium, ruthenium red) and the Ca2+ response was reduced proportionally by Piezo1 siRNA knockdown or in cells from Piezo1+/- mice. Investigation of Yoda1 effects on selected remodeling genes indicated that Piezo1 activation opposed cardiac fibroblast differentiation; data confirmed by functional collagen gel contraction assays. Piezo1 activation using Yoda1 or mechanical stretch also increased the expression of interleukin-6 (IL-6), a mechanosensitive pro-hypertrophic and pro-fibrotic cytokine, in a Piezo1-dependent manner. Multiplex kinase activity profiling combined with kinase inhibitor studies and phospho-specific western blotting, established that Piezo1 activation stimulated IL-6 secretion via a pathway involving p38 MAP kinase, downstream of Ca2+ entry. In summary, this study reveals that cardiac fibroblasts express functional Piezo1 channels coupled to reduced myofibroblast activation and increased secretion of paracrine signaling molecules that can modulate cardiac remodeling.

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Blythe, N. M., Stylianidis, V., Ludlow, M. J., Gilbert, H. T., Evans, E. L., Cuthbertson, K., Foster, R., Swift, J., Li, J., Drinkhill, M. J., van Nieuwenhoven, F. A., Porter, K. E., Beech, D. J., Turner, N. A.. 2019-04-10. Stimulation of cardiac fibroblast Piezo1 channels opposes myofibroblast differentiation and induces IL-6 secretion via Ca2+-mediated p38 MAP kinase activation. https://doi.org/10.1101/603456

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