title: Group I metabotropic glutamate receptor agonist DHPG modulates Kir4.1 protein and mRNA in cultured rat retinal Müller cells.
abstract: Müller cell gliosis is a general response in a variety of pathological alternations of the retina, which is characterized by the upregulated expression of glial fibrillary acidic protein (GFAP) and the downregulation of membrane K(+) conductance. We have demonstrated that downregulation of Kir K(+) currents in Müller cells in an experimental glaucoma model is due to activation of group I metabotropic glutamate receptor (mGluR I) by glutamate, which contributes to Müller cell gliosis. Here, whether and how activation of mGluR I modulate membrane Kir4.1 protein internalization and Kir4.1 mRNA expression were investigated in purified cultured rat retinal Müller cells using immunocytochemistry, Western blot and real-time PCR techniques. DHPG (10μM, a selective mGluR I agonist) treatment induced Müller cell gliosis, as evidenced by enhanced GFAP expression. Although total Kir4.1 proteins extracted from the DHPG-treated cells kept unchanged, Kir4.1 proteins in the cell membrane compartment were significantly decreased, which was prior to the change of GFAP in time course. In addition, DHPG (10 and 100μM) treatment induced a transient decrease in Kir4.1 mRNA expression in the cells. All these results suggest that activation of mGluR I by DHPG may decrease the number of functional Kir4.1 channels in purified cultured rat retinal Müller cells through modulating Kir4.1 protein and mRNA, thus contributing to Müller cell gliosis.
authors.affiliation: Department of Ophthalmology at Eye and ENT hospital, Fudan University, Shanghai 200031, China; Institutes of Brain Science, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.affiliation: Institutes of Brain Science, Fudan University, Shanghai 200031, China; Institute of Neurobiology, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Li
authors.affiliation: Institutes of Brain Science, Fudan University, Shanghai 200031, China; Institute of Neurobiology, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China.
authors.forename: Yanying
authors.initials: Y
authors.lastname: Miao
authors.affiliation: Institutes of Brain Science, Fudan University, Shanghai 200031, China; Institute of Neurobiology, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China.
authors.forename: Ling-Dan
authors.initials: LD
authors.lastname: Dong
authors.affiliation: Department of Ophthalmology at Eye and ENT hospital, Fudan University, Shanghai 200031, China; Institutes of Brain Science, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China.
authors.forename: Sheng-Hai
authors.initials: SH
authors.lastname: Zhang
authors.affiliation: Department of Ophthalmology at Eye and ENT hospital, Fudan University, Shanghai 200031, China; Institutes of Brain Science, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China. Electronic address: lwnn2006@gmail.com.
authors.forename: Jihong
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Ophthalmology at Eye and ENT hospital, Fudan University, Shanghai 200031, China; Institutes of Brain Science, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China.
authors.forename: Xing-Huai
authors.initials: XH
authors.lastname: Sun
authors.affiliation: Department of Ophthalmology at Eye and ENT hospital, Fudan University, Shanghai 200031, China; Institutes of Brain Science, Fudan University, Shanghai 200031, China; Institute of Neurobiology, Fudan University, Shanghai 200031, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200031, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China. Electronic address: zfwang@fudan.edu.cn.
authors.forename: Zhongfeng
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D063928:Ependymoglial Cells / Q000187:drug effects* / Q000378:metabolism; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005911:Gliosis; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists*; D012118:Resorcinols / Q000494:pharmacology*; D000098854:Kcnj10 Channel
chemical_list: D005904:Glial Fibrillary Acidic Protein; D000098854:Kcnj10 Channel; D024661:Potassium Channels, Inwardly Rectifying; D012333:RNA, Messenger; D018094:Receptors, Metabotropic Glutamate; D012118:Resorcinols; C079215:3,5-dihydroxyphenylglycine; D005998:Glycine
keywords: Cultured retinal Müller cells; DHPG; Gliosis; Kir4.1 mRNA; Kir4.1 protein