Piezo1-mediated microtubule destabilisation promotes extracellular matrix rigidity induced smooth muscle cell hypertrophy

Abstract

AbstractAbstract FigureBackground and PurposeDecreased aortic compliance is a precursor to numerous cardiovascular diseases. Compliance is regulated by the rigidity of the aortic wall and the vascular smooth muscle cells (VSMCs) within it. Extracellular matrix stiffening, observed during ageing, reduces compliance and contributes to hypertension. In response to increased rigidity, VSMCs generate enhanced contractile forces that result in VSMC stiffening and a further reduction in compliance. Due to a lack of suitablein vitromodels, the mechanisms driving VSMC response to matrix rigidity remain poorly defined.Experimental ApproachHuman aortic VSMCs were seeded onto polyacrylamide hydrogels whose rigidity mimicked either healthy or aged/diseased aortae. VSMC response to contractile agonist stimulation was measured through changes in cell area and volume. VSMCs were pre-treated with pharmacological agents prior to agonist stimulation to identify regulators of VSMC hypertrophy.Key ResultsVSMCs undergo a differential response to contractile agonist stimulation based on matrix rigidity. On pliable matrices, VSMCs contract, decreasing in cell area. Meanwhile, on rigid matrices VSMCs undergo a hypertrophic response, increasing in area and volume. Piezo1 mediated calcium influx drives VSMC hypertrophy by promoting microtubule destabilisation. Pharmacological stabilisation of microtubules or blocking calcium influx prevented VSMC hypertrophy on rigid matrices whilst maintaining contractility on pliable matrices.Conclusions and ImplicationsIn response to extracellular matrix rigidity, VSMCs undergo a hypertrophic response driven by piezo1-mediated microtubule destabilisation. Pharmacological targeting of this response blocks matrix rigidity induced VSMC hypertrophy whilst VSMC contractility on healthy mimicking matrices is unimpeded. Through delineating this rigidity-induced mechanism, we identify novel targets whose pharmacological inhibition may prove beneficial against VSMC-driven cardiovascular disease.