PEA-15 Knockdown Decreases Phagocytosis Function in Astrocytes

dc.contributor.authorLiu, Yang
dc.contributor.authorPang, Iok-Hou
dc.creatorBussan, Emily
dc.description.abstractPurpose: We used a phosphoproteomic approach to assess retinal proteins whose phosphorylation was affected by optic nerve (ON) injury. This study is to localize one of these proteins, Phosphoprotein Enriched in Astrocytes (PEA-15), in the retina and ON, and to test effect of siRNA knockdown PEA-15 on phagocytic function of astrocytes. Methods: Mouse retinal proteins labeled with CyDye-C2 were subjected to 2D-PAGE to determine changes of protein phosphorylation following ON crush. Protein spots with significant changes were selected for protein sequence analysis. Western blot and immunohistochemistry were used to confirm phosphorylation and localize PEA-15 in the retina and ON. Knockdown of PEA-15 protein in cultured mouse ON astrocytes by siRNA was confirmed by western blot. Phagocytic activity was assessed using pHrodo-conjugated synaptosomes. Results: PEA-15 phosphorylation was significantly augmented (ratios ≥ 1.5) in retinas of eyes with ON injury compared to control eyes. Densitometry analysis of western blots confirmed that ON crush significantly increased PEA-15 phosphorylation. PEA-15 was localized by immunohistochemistry in astrocytes in retina and ON. Treatment of cultured mouse astrocytes by PEA-15 targeted siRNA successfully knocked down PEA-15 protein as indicated by western blot. Knockdown of PEA-15 significantly (p< 0.05) suppressed the phagocytic activity of astrocytes compared to control cells containing PEA-15 protein. Conclusion: PEA-15 protein is present in retinal and ON astrocytes. Knockdown of this protein decreased phagocytic activity of these cells, suggesting PEA-15 is involved in the phagocytic function of astrocytes.
dc.titlePEA-15 Knockdown Decreases Phagocytosis Function in Astrocytes