SDF-1/CXCR4 axis induces apoptosis of human degenerative nucleus pulposus cells via NF-κB pathway / 基础医学与临床

ABSTRACT

Objective To investigate the role of SDF-1/CXCR4 axis on the apoptosis of human degenerative nucleus pulposus cells (NPCs) and its potential molecular mechanism .Methods The intervertebral disces tissues from clinical discectomy were divided into normal group and intervertebral disc degeneration ( IVD) group according to Pfirrmann classification.The different expression of SDF 1 and CXCR4 in human IVDs was tested by immunohistochemistry, quantify polymerase chain reaction (q-PCR) and Western blot.The primary degenerative NPCs were primary cultured.The generation Ⅲ~Ⅴ NPCs was treated with 10 ng/mL SDF-1, in the presence of or in the absence of CXCR4 siRNA transfection and 20 μmol/L NF-κB inhibitor (pyrrolidine dithiocar bamate,PDTC).The transfection efficiency and target protein of signal pathway were verified by Western blot , the apoptosis of NPCs were tested by Annexin V /PI, the nucleus transferlocation of P65 from NF-κB were tested by immunofluorescent method.Results SDF-1and CXCR4 were both expressed in all donor tissues, however, there was a significantly increased in the degenerative IVDs .The apoptosis of degenerative NPCs was expedited by SDF -1 stimulation,which was significantly suppressed by CXCR 4 silencing by siRNA (P<0.05).Furthermore, with SDF-1 stimulation,the expressions of phosphorylated P 65 was significantly increased and the P65 perssad transferred to the nucleuses,which could be suppressed by the NF-κB inhibitor, PDTC(P<0.05).Conclusions The expression levels of SDF-1 and CXCR4 are increased in degenerative NP tissue.The SDF-1/CXCR4 axis is considered to induce apoptotic of human degenerative NPCs via the NF-κB signaling pathway.