FIGURE 5.

Distinct effects of myosin IIA or IIB knockdown on compression stress‐induced human NP cells senescence. NP cells were transfected with siRNAs against myosin IIA or myosin IIB as described in experimental procedures. (A, B) Myosin IIA and IIB knockdown efficiency was shown by Western blot. (C, D) Human NP cells in different groups were stained with MRTF‐A (green) and DAPI (blue) (n = 20). Scale bar: 10 μm. (E, F) mRNA levels of the ECM remodelling proteinases (MMP3, MMP13 and ADAMTS5) and ECM component (COL1A, COL2A and aggrecan) were measured after the human NP cells were treated with siRNAs against myosin IIA or myosin IIB. (G, H) The proportions of cells in each cycle were measured through flow cytometry after the human NP cells were treated with siRNAs against myosin IIA or myosin IIB. (I, J) CDK4, Cyclin D1, p21 and p53 expression levels in different groups were measured through Western blot analysis and normalized to that of GAPDH. Data were presented as the mean ± SD (n = 3). #No significance, vs compression group; *P < .05, vs compression group; **P < .01, vs compression group; ***P < .001, vs compression group