Janus Kinase 2 and Tissue Inhibitor of Matrix Metalloproteinase‐1 Mediate the Protective Effects of Erythropoietin in In‐Vitro Model of Hypoxia Ischemia

Abstract

Studies have shown that erythropoietin (EPO) therapy significantly reduced brain injury and improved neurological function in rat model of neonatal hypoxia ischemia. Studies have shown that increase matrix metalloproteinase‐9 (MMP‐9) contributes to hypoxia ischemic brain injury. This study investigated if tissue inhibitor of matrix metalloproteinase‐1 (TIMP‐1) and its upstream signaling molecule Janus kinase‐2 (JAK‐2) are involved in EPO‐induced neuroprotection in an in vitro model of hypoxia ischemia.Hypoxia ischemia was induced in neuronal growth factor differentiated PC12 cells by 2 hours of oxygen and glucose deprivation. The cells were treated immediately before and during hypoxia ischemia with either: EPO, EPO + AG490 (JAK‐2 inhibitor), AG490, EPO + TIMP‐1 antibody, or TIMP‐1 antibody. Cell death, phosphorylation of JAK‐2, signal transducers and activators of transcription protein‐3 (STAT‐3), TIMP‐1 expression, and MMP‐9 activity were measured and compared with normoxic group.Our data showed that EPO significantly increased cell survival, associated with increased TIMP‐1 expression, phosphorylation of JAK‐2, STAT‐3, and decreased MMP‐9 activity. These protective effects of EPO were significantly reduced by inhibition of JAK‐2 and TIMP‐1. Conclusion: JAK‐2 and TIMP‐1 are necessary for EPO‐induced neuroprotection hypoxia ischemia injury. Supported by NIH, grant NS052492.