Introduction: A disintegrin and metalloproteinase 33 (ADAM33) has been identified as a susceptibility gene for asthma. In particular, the level of soluble form of ADAM33 (sADAM33) is known to correlate with airway hyperresponsiveness (AHR) that is ultimately determined by the mechanical behaviors of ASMCs. However, few have studied how ADAM33 would affect ASMC mechanics. Here, we manipulated the expression of sADAM33 in cultured ASMCs and then assessed the corresponding changes in biomechanical behaviors of the cells.
Method: ASMCs from Sprague Dawley (SD) rats were either overexpressed sADAM33 or silenced by lentivirus transfection, and the mRNA and protein were quantitated by RT-PCR and Western blot. Then the cells were assessed for their traction force by FTTM, stiffness by OMTC, migration by wound healing and transwell assay respectively. GST Pull-down assay and H-1152 were used to evaluate Rho and inhibit ROCK activity respectively.
Results: ASMCs with sADAM33 overexpression generated greater traction force, were stiffer and more contractile when stimulated by either histamine or KCL, and exhibited stronger ability of lateral -migration and higher Rho activity as well as dramatically increased expression of α-actin, calponin, SM-MHC and integrin β1. However these changes can be attenuated by H-1152.
Conclusion: Taken together, these results indicated that modulation of sADAM33 gene expression strongly alters biomechanical behavior of ASMCs, probably through regulating the phenotype transition by Rho/ROCK pathway. Thus, sADAM33 may be an important regulator of mechanical behaviors of ASMCs. This study may be important to fully understand the underlying mechanisms of AHR and remodeling in asthma.