Spatiotemporal patterns and essential role of MSK1 expression after rat spinal cord injury.

Mitogen and stress activated protein kinase (MSK1) protein was initially identified as a particularly interesting protein of mitogen activated protein kinase. It was reported to enhance Bad's phosphorylation to protect cell death, suggesting that MSK1 represents a new type of anti-cell death gene. Moreover, recent study has shown that MSK1 is involved in negative feedback pathways that are crucial to prevent uncontrolled inflammation. However, its function and expression in the central nervous system lesion are not been understood very well. In this study, we performed an acute spinal cord injury (SCI) model in adult rats and studied the dynamic changes of MSK1 expression in spinal cord. Western blot and immunohistochemistry analysis revealed that MSK1 was present in normal spinal cord. It gradually decreased, reached a peak at 3 days after SCI, and then increased during the following days. Immunofluorescence double labeling revealed that MSK1 was co-expressed with NeuN and GFAP, respectively. Interesting, after injury, MSK1 expression was decreased predominantly in astrocytes, which highly expressed proliferating cell nuclear antigen, a marker for proliferating cells. In conclusion, this is the first description of MSK1 expression in spinal cord. Our data suggested that MSK1 might play important roles in CNS pathophysiology after SCI.