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Abstract: TH-PO552

M2 Macrophages Promote Mouse Aortic Smooth Muscle Cells Calcification by the SGK1-TGFβ1 Axis

Session Information

Category: Bone and Mineral Metabolism

  • 401 Bone and Mineral Metabolism: Basic

Authors

  • Wu, Beibei, Institute of Nephrology, Zhong Da Hospital, Southeast University, School of Medicine, Nanjing, JIANGSU , China
  • Zhu, Xiaodong, Institute of Nephrology, Zhong Da Hospital, Southeast University, School of Medicine, Nanjing, JIANGSU , China
  • Liu, Yuqiu, Institute of Nephrology, Zhong Da Hospital, Southeast University, School of Medicine, Nanjing, JIANGSU , China
  • Jiang, Yuteng, Institute of Nephrology, Zhong Da Hospital, Southeast University, School of Medicine, Nanjing, JIANGSU , China
  • Liu, Bi-Cheng, Institute of Nephrology, Zhong Da Hospital, Southeast University, School of Medicine, Nanjing, JIANGSU , China
  • Zhang, Xiaoliang, Institute of Nephrology, Zhong Da Hospital, Southeast University, School of Medicine, Nanjing, JIANGSU , China
Background

Macrophages play an important role in vascular calcification (VC). Recent researches show that SGK1 is a highly attractive candidate for developing vascular smooth muscle cells (VSMCs) calcification. Importantly, TGFβ1 induces VC through regulating osteo-/chondrogenic transdifferentiation of VSMCs. However, whether macrophages promote VSMCs osteo-/chondrogenic transdifferentiation via SGK1 and the associated mechanisms is unknown.

Methods

Mouse aortic smooth muscle cells (MAoSMCs) with the supernatant from diverse stimutited-macrophages (M0-CM, M2-CM, M2-EMD-CM; EMD: SGK1 inhibitor) were treated with or without TGFβ1 receptor inhibitor. Calcium deposition was evaluated by alizarin red and von Kossa staining. Intracellular calcum contents were measured via calcium quantification kit. Expressions of specifc-osteogenic markers, SGK1 and TGFβ1 were examined by RT-qPCR, western blotting, immunofluorescence staining or Elisa kit.

Results

MAoSMCs produced significant calcium deposits in M2-CM. Furthermore, M2-CM promoted MAoSMCs transdifferentiation, which was characterized by expression of osteo-/chondrogenic markers (Runx2, ALPL, FGF23) or decrease of the MAoSMCs marker (SM22α). Exploring the mechanism of the above phenomenon, we found that the expression of SGK1 and TGFβ1 were significantly increased in M2 group compared with M0 group (P<0.05). Interestingly, when blocking SGK1 expression, the expression of TGFβ1 was down-regulated in M2. In addition, inhibiting expression of SGK1 or TGFβ1 can partially blocked MAoSMCs osteo-/chondrogenic transdifferentiation and calcification. Subsequent analyses by using calcium quantification kit, alizarin red and von kossa staining showed that recombinant mouse TGFβ1 increased calcium content in MAoSMCs and promoted MAoSMCs transdifferentiation, which the expression of osteo-/chondrogenic markers obviously increased(P<0.05), while MAoSMCs marker markly decreased(P<0.05).

Conclusion

M2 macrophages SGK1-TGFβ1 axis contribute to promote MAoSMCs osteo-/chondrogenic transdifferentiation.