Piezo1-mediated microtubule destabilisation promotes extracellular
matrix rigidity induced smooth muscle cell hypertrophy
Abstract
Decreased 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 suitable in vitro models, the
mechanisms driving VSMC response to matrix rigidity remain poorly
defined. Human 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. VSMCs 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. In 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.