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Published on: June 21, 2013
Diversity of aquaporin mRNA expressed by rat and human retinas
Solveig Tenckhoff1, Margrit Hollborn, Leon Kohen
1Department of Ophthalmology and Eye Clinic, University of Leipzig Medical Faculty, Liebigstr. 10-14, D-04103 Leipzig, Germany.
Abstract:
Muller glial cells of the sensory retina mediate K+ and water fluxes that are facilitated by aquaporin-4 (AQP4) water channels and by Kir4.1-K+ channels. However, it is not known which subtypes of aquaporins are expressed in the mammalian retina. Using RT-PCR, we found that both human and rat retinas express mRNA for a diversity of water channel proteins. The human retina expresses mRNAs for AQP0 to AQP12 proteins. Using real-time PCR, we found that the mRNAs for AQP4 and Kir4.1 are downregulated in retinas that were obtained from patients with proliferative retinopathy compared with post-mortem controls. The data suggest that the development of proliferative gliosis is accompanied by disturbed transglial water and ion movements.
Insights
Muller glial cells in the retina utilize aquaporin (AQP) water channels and Kir4.1-K+ channels for ion and water transport. Proliferative retinopathy is linked to reduced levels of AQP4 and Kir4.1, suggesting impaired glial function.
Area of Science:
- Neuroscience
- Ophthalmology
- Cell Biology
Background:
- Muller glial cells are crucial for retinal function, regulating ion and water homeostasis.
- These cells express aquaporin-4 (AQP4) and Kir4.1 potassium channels, facilitating K+ and water fluxes.
- The full spectrum of aquaporin subtypes expressed in the mammalian retina remains largely uncharacterized.
Purpose of the Study:
- To investigate the expression profile of aquaporin subtypes in the mammalian retina.
- To determine the expression levels of AQP4 and Kir4.1 in retinas affected by proliferative retinopathy.
Main Methods:
- Reverse transcription polymerase chain reaction (RT-PCR) was employed to detect aquaporin mRNA expression in human and rat retinas.
- Real-time PCR was utilized to quantify the expression levels of AQP4 and Kir4.1 mRNAs in patient and control retinas.
Main Results:
- Human and rat retinas express a diverse range of aquaporin subtype mRNAs (AQP0-AQP12 in humans).
- Significantly lower levels of AQP4 and Kir4.1 mRNAs were observed in retinas from patients with proliferative retinopathy compared to post-mortem controls.
- These findings indicate a downregulation of key water and ion channel components in diseased retinas.
Conclusions:
- The mammalian retina expresses a wide array of aquaporin water channels.
- Downregulation of AQP4 and Kir4.1 in proliferative retinopathy suggests a disruption of transglial water and ion transport.
- These molecular changes may contribute to the pathogenesis of proliferative gliosis in the retina.
