Interleukin 6 induces osteogenic differentiation and calcification of human umbilical artery smooth muscle cells via trans-signaling pathway / 中华风湿病学杂志

ABSTRACT

Objective:To explore the trans-membrane signaling mechanism of interleukin-6 (IL-6)-induced osteogenic differentiation and calcification of human umbilical artery smooth muscle cells (HUASMCs).Methods:HUASMCs were primarily cultured in vitro and were stimulated with IL-6, IL-6+solutable IL-6 receptor (sIL-6R), IL-6+sIL-6R+solutable gp130 (sgp130), or vehicle (blank control). Alizarin red and Von Kossa staining were used for detecting cell calcification, Western blot was used to test the protein expression of tissue-nonspecific alkaline phosphatase (TNAP), osteopontin (OPN), bone morphogenetic protein-2 (BMP-2) and Runt related transcription factor 2 (Runx2), and immunofluorescence was used to examine the mIL-6R expression of HUASMCs. The comparison of measurement date between the two groups was conducted by t-test. The comparison of measurement date between multiple groups was conducted by one-way analysis of variance (ANOVA). Results:The intensity severity of calcification stain was IL-6+sIL-6R group >IL-6+sIL-6R+sgp130 group>IL-6 group=blank control. After stimulated for 12 hours, the TNAP expression in blank control, IL-6 group, IL-6+sIL-6R group, IL-6+sIL-6R+sgp130 group were (0.44±0.08), (0.52±0.14), (0.84±0.16) and (0.55±0.10) respectively ( F=290.96, P<0.001). After stimulated for 3 days, the OPN expression in blank control, IL-6 group, IL-6+sIL-6R group, IL-6+sIL-6R+sgp130 group were (0.61±0.84), (0.95±0.16), (1.65±0.24) and (0.99±0.10) respectively ( F=507.72, P<0.001). After stimulated for 12 hours, the BMP-2 expression in blank control, IL-6 group, IL-6+sIL-6R group, IL-6+sIL-6R+sgp130 group were (0.77±0.05), (1.69±0.16), (2.81±0.26) and (0.57±0.12) respectively ( F=959.09, P<0.001). After stimulated for 3 days, the Runx2 expression in blank control, IL-6 group, IL-6+sIL-6R group,IL-6+sIL-6R+sgp130 group were (0.57±0.03) , (0.92±0.10), (1.31±0.13) and (0.66±0.06) respectively ( F=1141.27, P<0.001). Comparing with Jurkat cells (positive control) and CEM cells (negative control), HUASMCs limited expressed mIL-6R. Conclusion:IL-6 may induce HUASMCs osteogenic differentiation and calcification mainly via the sIL-6R-mediated trans-signaling pathway.