Activation of T‐LAK‐cell‐originated protein kinase‐mediated antioxidation protects against focal cerebral ischemia–reperfusion injury

Abstract

T-LAK-cell-originated protein kinase (TOPK), a MAPKK-like kinase, is crucial for neural progenitor cell proliferation; however, the function of TOPK and the molecular mechanism underlying cerebral ischemia-reperfusion injury remains unknown. Therefore, we investigated the role of TOPK in experimental stroke. Sprague-Dawley rats underwent transient middle cerebral artery occlusion (tMCAO) and reperfusion, and TOPK small interfering RNA (siRNA) was delivered by intracerebroventricular injection at the beginning of MCAO. After TOPK overexpression and H 2 O 2 stimulation in PC12 neuronal cells, antioxidative proteins, apoptosis-related proteins and signal pathways were detected by western blot analysis, the levels of the peroxidation products (malondialdehyde and 3-nitrotyrosine) were measured with ELISA. Phosphorylation of TOPK was increased in rat cortical neurons following tMCAO. TOPK overexpression in PC12 cells augmented levels of antioxidative proteins (peroxiredoxin 1 and 2, heme oxygenase 1 and manganese superoxide dismutase), as well as total superoxide dismutase activity, along with inhibition of malondialdehyde and 3-nitrotyrosine upon H 2 O 2 stimulation. TOPK overexpression increased cell viability and reduced expression of caspase 3 and caspase 12 in PC12 cells in response to H 2 O 2 . The p-ERK level was increased by TOPK overexpression, and antioxidative protection afforded by TOPK was abolished by blocking the extracellular signal-regulated kinase pathway in PC12 cells. TOPK siRNA increased the infarct volume and reduced total superoxide dismutase activity in the cortex in vivo after MCAO. These data reveal that activating TOPK confers neuroprotection against focal cerebral ischemiareperfusion injury by antioxidative function, in part through activation of the extracellular signal-regulated kinase pathway.Abbreviations 3-NT, 3-nitrotyrosine; Akt, protein kinase B; ERK, extracellular signal-regulated kinase; HO-1, heme oxygenase 1; MDA, malondialdehyde; Prx-1, peroxiredoxin 1; siRNA, small interfering RNA; tMCAO, transient middle cerebral artery occlusion; TOPK, T-LAK-cell-originated protein kinase; TTC, 2,3,5-triphenyltetrazolium chloride.

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Targeting Oxidative Stress and Inflammation to Prevent Ischemia-Reperfusion Injury

“…T-LAK-cell-originated protein kinase (TOPK) is involved in many biological functions, including the inhibition of apoptosis, promotion of cell growth, and antioxidation. TOPK has the ability to regulate oxidative stress: in H 2 O 2 -induced oxidative stress, TOPK is significantly activated, and p-TOPK levels begin to increase at 15 min, peak at 30-60 min, and return to basal levels at 120 min, while a TOPK inhibitor aggravates H 2 O 2 -induced oxidative stress damage (Zhao et al, 2014b). CIP promotes TOPK phosphorylation, significantly enhances TOPK activity, and reduces reperfusion injury (Zhao et al, 2014a).…”