Stiffness Mediated‐Mechanosensation of Airway Smooth Muscle Cells on Linear Stiffness Gradient Hydrogels

Abstract

In obstructive airway diseases such as asthma and chronic obstructive pulmonary disease, the extracellular matrix (ECM) protein amount and composition of the airway smooth muscle (ASM) is often remodelled, likely altering tissue stiffness. The underlying mechanism of how human ASM cell (hASMC) mechanosenses the aberrant microenvironment is not well understood. Physiological stiffnesses of the ASM layer were measured by uniaxial compression tester using porcine ASM layers under 0, 5 and 10% longitudinal stretch above in situ length. Linear stiffness gradient hydrogels (2–30 kPa range) were fabricated and functionalized with ECM proteins, collagen I (ColI), fibronectin (Fn) and laminin (Ln), to recapitulate the above‐measured range of stiffnesses with an Atomic Force Microscope. Overall, hASMC mechanosensation exhibited a clear correlation with the underlying hydrogel stiffness with some specificity to ECM protein type. Cell size, nuclear size and contractile marker alpha‐smooth muscle actin (αSMA) expression showed a strong correlation to substrate stiffness. Mechanosensation, assessed by Lamin‐A intensity and YAP nuclear translocalization, exhibited stiffness‐mediated behaviour only on ColI and Fn‐coated hydrogels. Inhibition studies using blebbistatin or Y27632 attenuated most mechanotransduction‐derived cell morphological responses, αSMA and Lamin‐A expression and YAP nuclear translocalization (blebbistatin only). This study highlights the interplay and complexities between stiffness and ECM protein type on hASMC mechanosensation, relevant to airway remodelling in obstructive airway diseases.This article is protected by copyright. All rights reserved