Stress-induced changes in neuronal Aquaporin-9 (AQP9) in a retinal ganglion cell-line.
The water channel, Aquaporin-9 (AQP9) is enriched in selected neuronal populations and is unique its ability to act as a lactate-glycerol channel supplying neurons with alternative fuel under ischaemic conditions. AQP9 was detected in RGC-5 cells, a retinal ganglion cell-line, primary RGCs, and retina by Western blotting, real-time PCR (RT-PCR) and immunohistochemistry. RGC-5 cells subjected to a hypotonic stress increased their cell volume that was blocked by known inhibitor of AQP9 (phloretin (40 microM)). RGC-5 cells subjected to hypoxia, showed an up-regulation in AQP9 expression as judged by Western blotting and RT-PCR. Similarly, hypotonic shock (50%) increased AQP9 expression as determined by RT-PCR. AQP9 is involved in energy balance as a glycerol-lactate channel and also appears to regulate cell volume in retinal ganglion neurons. This water channel may play a key role in retinal ganglion pathology.
Dibas
Adnan
A
Department of Pharmacology & Neuroscience, University of North Texas Health Science Center at Fort Worth, TX 76107, USA. adibas@hsc.unt.edu
Yang
Ming-Hui
MH
Bobich
Joseph
J
Yorio
Thomas
T
D000818:Animals; D020346:Aquaporins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D015687:Cell Hypoxia; D002460:Cell Line; D048429:Cell Size; D007038:Hypotonic Solutions / Q000378:metabolism; D007150:Immunohistochemistry; D009997:Osmotic Pressure; D010693:Phloretin / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013312:Stress, Physiological / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D013997:Time Factors; D015854:Up-Regulation; D014882:Water-Electrolyte Balance / Q000187:drug effects
C491637:Aqp9 protein, rat; D020346:Aquaporins; D007038:Hypotonic Solutions; D012333:RNA, Messenger; D010693:Phloretin