Glycolytic enzyme PKM2 regulates cell senescence but not inflammation in the process of osteoarthritis  

作　　者：Bo Liu Chenzhong Wang Ziyu Weng Yi Yang Hong Zhao Yueqi Zhang Qinming Fei Yi Shi Chi Zhang 

机构地区：[1]Department of Orthopedic Surgery,Zhongshan Hospital,Fudan University,Shanghai 200032,China [2]Biomedical Research Centre,Zhongshan Hospital,Fudan University,Shanghai 200032,China

出　　处：《Acta Biochimica et Biophysica Sinica》2023年第9期1425-1433,共9页生物化学与生物物理学报（英文版）

基　　金：supported by the grant from the National Natural Science Foundation of China(No.81971308 to C.Z.).

摘　　要：Chondrocyte senescence is an important mechanism underlying osteoarthritis in the senile population and is characterized by reduced expressions of the extracellular matrix proteins.The involvement of glycolysis and the tricarboxylic acid cycle in the development of osteoarthritis is inclusive.The present study aims to investigate the role of the glycolytic enzyme M2 isoform of pyruvate kinase(PKM2)in chondrocytes in senescence and inflammation.Primary chondrocytes are isolated from the knee joints of neonatal mice.Small interfering RNAs(siRNAs)against PKM2 are transfected using lipofectamine.RNA sequencing is conducted in primary chondrocytes with the PKM2 gene deleted.Cell apoptosis,autophagy,reactive oxygen species measurement,and senescent conditions are examined.The glycolytic rate in cells is measured by Seahorse examination.Interleukin 1-β(IL-1β)increases the protein expressions of matrix metallopeptidases(MMP)13 and PKM2 and reduces the protein expression of collagen type II(COL2A1)in primary chondrocytes.Silencing of PKM2 alters the protein expressions of MMP13,PKM2,and COL2A1 in the same pattern in quiescent and stimulated chondrocytes.RNA sequencing analysis reveals that PKM2 silencing reduces senescent biomarker p16INK4a expression.Compared with low-passage chondrocytes,high-passage chondrocytes exhibit increased expression of p16INK4a and reduced expression of COL2A1.Silencing of PKM2 reduces SA-β-Gal signals and increases COL2A1 expression in high-passage chondrocytes.Seahorse assay reveals that PKM2 deletion favors the tricarboxylic acid cycle in mitochondria in low-but not in high-passage chondrocytes.In summary,the glycolytic enzyme PMK2 modulates chondrocyte senescence but does not participate in the regulation of inflammation.

关 键 词：CHONDROCYTE PKM2 P16INK4A SENESCENCE metabolic reprogramming 

分 类 号：R73[医药卫生—肿瘤]