Hyaluronan-induced ASMC contraction is mediated by PC. A: to determine the effect of high-molecular weight hyaluronan (HMW HA) and short-fragment HA (sHA) on ASMC contraction in collagen gels, cells were prepared in basal media alone (BM) or supplemented with 0.5 mg/ml HMW HA (n = 3) or sHA (n = 3) and combined with neutralized collagen. Gels contracted over 40 h, and gel areas were measured at time 0 and at 40 h to calculate percent contraction over time. Data are presented as means ± SE. B: contracted gels were fixed in 4% PFA and paraffin embedded, and sections were stained with acetylated tubulin (red; nuclei were stained with DAPI in blue) to visualize PC (arrows); images are at ×400 magnification. C: ASMCs were prepared in basal media supplemented with DMSO vehicle control (n = 3) or supplemented with either 0.5 mg/ml sHA plus DMSO (n = 3) or 0.5 mg/ml HMW HA plus DMSO (n = 3; left side of graph). Another set of gels was prepared with ASMCs in basal media plus DMSO as vehicle control (n = 9), with 15 μM HPI-4 plus 0.5 mg/ml sHA (n = 6) or with 15 μM HPI-4 plus 0.5 mg/ml HMW HA (n = 6; right side of graph). Percent contraction over 40 h was determined; data are presented as means ± SE. D: collagen gels were prepared with scrambled control of IFT88 KD ASMCs in basal media alone (n = 12) or supplemented with either sHA (n = 6) or HMW HA (n = 9; left side of graph) and allowed to contract for 40 h. Percent contraction was determined at 40 h; data are presented as means ± SE. NS, not significant.