Exp Mol Med.  2006 Jun;38(3):310-319.

Cell type-specific upregulation of myristoylated alanine-rich C kinase substrate and protein kinase C-alpha, -beta I, -beta II, and -delta in microglia following kainic acid-induced seizures

• Eun SY
• Kim EH
• Kang KS
• Kim HJ
• Jo SA
• Kim SJ
• Jo SH
• Kim SJ
• Blackshear PJ
• Kim J

Abstract

Myristoylated alanine-rich C kinase substrate (MARCKS) is a widely distributed protein kinase C (PKC) substrate and has been implicated in actin cytoskeletal rearrangement in response to extracellular stimuli. Although MARCKS was extensively examined in various cell culture systems, the physiological function of MARCKS in the central nervous system has not been clearly understood. We investigated alterations of cellular distribution and phosphorylation of MARCKS in the hippocampus following kainic acid (KA)-induced seizures. KA (25 mg/kg, i.p.) was administered to eight to nine week-old C57BL/6 mice. Behavioral seizure activity was observed for 2 h after the onset of seizures and was terminated with diazepam (8 mg/kg, i.p.). The animals were sacrificed and analyzed at various points in time after the initiation of seizure activity. Using double-labeling immunofluorescence analysis, we demonstrated that the expression and phosphorylation of MARCKS was dramatically upregulated specifically in microglial cells after KA-induced seizures, but not in other types of glial cells. PKC alpha, beta I, beta II and delta, from various PKC isoforms examined, also were markedly upregulated, specifically in microglial cells. Moreover, immunoreactivities of phosphorylated MARCKS were co-localized in the activated microglia with those of the above isoforms of PKC. Taken together, our in vivo data suggest that MARCKS is closely linked to microglial activation processes, which are important in pathological conditions, such as neuroinflammation and neurodegeneration.

Keyword

gene expression; kainic acid; microglia; myristoylated alanine-rich C kinase substrate; protein kinase C; seizures

MeSH Terms

Up-Regulation/drug effects
Time Factors
Seizures/chemically induced/*metabolism
Protein Kinase C-delta/analysis
Protein Kinase C-alpha/analysis
Protein Kinase C/*analysis
Protein Biosynthesis/drug effects
Phosphorylation/drug effects
Microscopy, Confocal
Microglia/cytology/drug effects/*metabolism
Mice, Inbred C57BL
Mice
Membrane Proteins/*analysis/metabolism
Kainic Acid/*toxicity
Isoenzymes/analysis
Intracellular Signaling Peptides and Proteins/*analysis/metabolism
Immunohistochemistry
Animals