AQP5 is differentially regulated in astrocytes during metabolic and traumatic injuries.
Water movement plays vital roles in both physiological and pathological conditions in the brain. Astrocytes are responsible for regulating this water movement and are the major contributors to brain edema in pathological conditions. Aquaporins (AQPs) in astrocytes play critical roles in the regulation of water movement in the brain. AQP1, 3, 4, 5, 8, and 9 have been reported in the brain. Compared with AQP1, 4, and 9, AQP3, 5, and 8 are less studied. Among the lesser known AQPs, AQP5, which has multiple functions identified outside the central nervous system, is also indicated to be involved in hypoxia injury in astrocytes. In our study, AQP5 expression could be detected both in primary cultures of astrocytes and neurons, and AQP5 expression in astrocytes was confirmed in 1- to 4-week old primary cultures of astrocytes. AQP5 was localized on the cytoplasmic membrane and in the cytoplasm of astrocytes. AQP5 expression was downregulated during ischemia treatment and upregulated after scratch-wound injury, which was also confirmed in a middle cerebral artery occlusion model and a stab-wound injury model in vivo. The AQP5 increased after scratch injury was polarized to the migrating processes and cytoplasmic membrane of astrocytes in the leading edge of the scratch-wound, and AQP5 over-expression facilitated astrocyte process elongation after scratch injury. Taken together, these results indicate that AQP5 might be an important water channel in astrocytes that is differentially expressed during various brain injuries.
Neuroscience Research Institute & Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100191, China.
Rui Chao
RC
Chai
Jiao Hua
JH
Jiang
Ann Yuen Kwan
AY
Wong
Feng
F
Jiang
Kai
K
Gao
Greg
G
Vatcher
Albert Cheung
AC
Hoi Yu
D000818:Animals; D000831:Animals, Newborn; D051402:Aquaporin 5 / Q000378:metabolism*; D001253:Astrocytes / Q000378:metabolism*; D001921:Brain / Q000378:metabolism* / Q000473:pathology*; D001930:Brain Injuries / Q000473:pathology*; D015687:Cell Hypoxia / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D004195:Disease Models, Animal; D004622:Embryo, Mammalian; D005786:Gene Expression Regulation / Q000502:physiology*; D020244:Infarction, Middle Cerebral Artery / Q000473:pathology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009474:Neurons / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013347:Subcellular Fractions / Q000378:metabolism / Q000473:pathology; D013997:Time Factors; D014162:Transfection; D014947:Wounds and Injuries / Q000473:pathology
C496038:Aqp5 protein, mouse; D051402:Aquaporin 5
MCAO; aquaporin; ischemia; scratch-wound; stab-wound