title: 24(S)-Hydroxycholesterol protects the ex vivo rat retina from injury by elevated hydrostatic pressure.
abstract: In the central nervous system, 24(S)-hydroxycholesterol (24(S)-HC) is an oxysterol synthesized from cholesterol by cholesterol 24-hydroxylase (CYP46A1) encoded by the cyp46a1 gene. In the present study using a rat ex vivo glaucoma model, we found that retinal 24(S)-HC synthesis is facilitated by pressure elevation. Moreover, we found that 24(S)-HC is neuroprotective against pressure mediated retinal degeneration. Quantitative real-time RT-PCR, ELISA, and immunohistochemistry revealed that elevated pressure facilitated the expression of cyp46a1 and CYP46A1. Immunohistochemically, the enhanced expression of CYP46A1 was mainly observed in retinal ganglion cells (RGC). LC-MS/MS revealed that 24(S)-HC levels increased in a pressure-dependent manner. Axonal injury and apoptotic RGC death induced by 75 mmHg high pressure was ameliorated by exogenously administered 1 μM 24(S)-HC. In contrast, voriconazole, a CYP46A1 inhibitor, was severely toxic even at normobaric pressure. Under normobaric conditions, 30 μM 24(S)-HC was required to prevent the voriconazole-mediated retinal damage. Taken together, our findings indicate that 24(S)-HC is facilitated by elevated pressure and plays a neuroprotective role under glaucomatous conditions, while voriconazole, an antifungal drug, is retinotoxic. 24(S)-HC and related compounds may serve as potential therapeutic targets for protecting glaucomatous eyes from pressure-induced injuries.
authors.affiliation: Department of Ophthalmology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ishikawa
authors.affiliation: Department of Ophthalmology, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshitomi
authors.affiliation: The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, M.O., USA.|Center for Brain Research in Mood Disorders, Washington University School of Medicine, St. Louis, M.O., USA.|Department of Psychiatry, Washington University School of Medicine, St. Louis, M.O., USA.
authors.forename: Charles F
authors.initials: CF
authors.lastname: Zorumski
authors.affiliation: The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, M.O., USA.|Center for Brain Research in Mood Disorders, Washington University School of Medicine, St. Louis, M.O., USA.|Department of Psychiatry, Washington University School of Medicine, St. Louis, M.O., USA.
authors.forename: Yukitoshi
authors.initials: Y
authors.lastname: Izumi