Affiliation:
1. School of Pharmacy University of East Anglia Norwich UK
2. Section of Cardiorespiratory Medicine University of Cambridge, VPD Heart and Lung Research Institute Cambridge UK
3. Henry Wellcome Laboratory for Cell Imaging University of East Anglia Norfolk UK
4. School of Pharmacy University College London London UK
Abstract
AbstractBackground 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). Extracellular matrix stiffening, observed during ageing, reduces compliance. In response to increased rigidity, VSMCs generate enhanced contractile forces that result in VSMC stiffening and a further reduction in compliance. Mechanisms driving VSMC response to matrix rigidity remain poorly defined.Experimental ApproachHuman aortic‐VSMCs were seeded onto polyacrylamide hydrogels whose rigidity mimicked either healthy (12 kPa) or aged/diseased (72 kPa) aortae. VSMCs were treated with pharmacological agents prior to agonist stimulation to identify regulators of VSMC volume regulation.Key ResultsOn pliable matrices, VSMCs contracted and decreased in cell area. Meanwhile, on rigid matrices VSMCs displayed a hypertrophic‐like response, increasing in area and volume. Piezo1 activation stimulated increased VSMC volume by promoting calcium ion influx and subsequent activation of PKC and aquaporin‐1. Pharmacological blockade of this pathway prevented the enhanced VSMC volume response on rigid matrices whilst maintaining contractility on pliable matrices. Importantly, both piezo1 and aquaporin‐1 gene expression were up‐regulated during VSMC phenotypic modulation in atherosclerosis and after carotid ligation.Conclusions and ImplicationsIn response to extracellular matrix rigidity, VSMC volume is increased by a piezo1/PKC/aquaporin‐1 mediated pathway. Pharmacological targeting of this pathway specifically blocks the matrix rigidity enhanced VSMC volume response, leaving VSMC contractility on healthy mimicking matrices intact. Importantly, upregulation of both piezo1 and aquaporin‐1 gene expression is observed in disease relevant VSMC phenotypes.
Funder
British Heart Foundation
Biotechnology and Biological Sciences Research Council