Glial expression of the 90-kDa heat shock protein (HSP90) and the 94-kDa glucose-regulated protein (GRP94) following an excitotoxic lesion in the mouse hippocampus.
Heat shock proteins (HSPs) are immediately expressed in neuronal and glial cells under various stressful conditions and play a protective role through molecular chaperones. Although several studies have been focused on the expression of HSPs, little is known about HSP90s expression in glial cells under neuropathological conditions. In this study, we evaluated the expression pattern of the glial cell-related HSP90 and GRP94 proteins, following the induction of an excitotoxic lesion in the mouse brain. Adult mice received an intracerebroventricular injection of kainic acid; the brain tissue was then analyzed immunohistochemically for HSPs and double labeling using glial markers. HSPs expression was quantified by Western blot analysis. Excitotoxic damage was found to cause pyramidal cell degeneration in the CA3 region of the hippocampus. In the injured hippocampus, reactive microglia/macrophages expressed HSP90 from 12 h until 7 days postlesion (PL), showing maximal levels at day 1. In parallel, hippocampal reactive astrocytes showed the expression of GRP94 from 12 h until 7 days PL. In general, HSPs expression was transient, peaked at 1-3 days PL and reached basal levels by day 7. For the first time, our data demonstrate the injury-induced expression of HSP90 and GRP94 in glial cells, which may contribute to the mechanism of glial cell protection and adaptation in response to damage, thereby playing an important role in the evolution of the glial response and the excitotoxic lesion outcome. HSP90 may provide antioxidant protective mechanisms against microglia/macrophages, whereas GRP94 may stabilize the astroglial cytoskeleton and participate in astroglial antioxidant mechanisms.
Jeon
Gye Sun
GS
Department of Anatomy, College of Medicine, Seoul National University, Seoul, Korea.
Park
Sang Wook
SW
Kim
Dong Woon
DW
Seo
Je Hoon
JH
Cho
Jaeyoung
J
Lim
So Young
SY
Kim
Seong Deok
SD
Cho
Sa Sun
SS
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism; D015415:Biomarkers; D002135:Calcium-Binding Proteins / Q000378:metabolism; D004660:Encephalitis / Q000378:metabolism / Q000503:physiopathology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005911:Gliosis / Q000378:metabolism / Q000503:physiopathology; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D007276:Injections, Intraventricular; D007608:Kainic Acid; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D008840:Microfilament Proteins; D017628:Microglia / Q000166:cytology / Q000378:metabolism; D009410:Nerve Degeneration / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D009457:Neuroglia / Q000378:metabolism*; D009498:Neurotoxins; D018384:Oxidative Stress / Q000502:physiology*; D017966:Pyramidal Cells / Q000473:pathology
C491049:Aif1 protein, mouse; D000975:Antioxidants; D015415:Biomarkers; D002135:Calcium-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009498:Neurotoxins; C018551:glucose-regulated proteins; D007608:Kainic Acid