title: Müller cell metabolic chaos during retinal degeneration.
abstract: Müller cells play a critical role in retinal metabolism and are among the first cells to demonstrate metabolic changes in retinal stress or disease. The timing, extent, regulation, and impacts of these changes are not yet known. We evaluated metabolic phenotypes of Müller cells in the degenerating retina. Retinas harvested from wild-type (WT) and rhodopsin Tg P347L rabbits were fixed in mixed aldehydes and resin embedded for computational molecular phenotyping (CMP). CMP facilitates small molecule fingerprinting of every cell in the retina, allowing evaluation of metabolite levels in single cells. CMP revealed signature variations in metabolite levels across Müller cells from TgP347L retina. In brief, neighboring Müller cells demonstrated variability in taurine, glutamate, glutamine, glutathione, glutamine synthetase (GS), and CRALBP. This variability showed no correlation across metabolites, implying the changes are functionally chaotic rather than simply heterogeneous. The inability of any clustering algorithm to classify Müller cell as a single class in the TgP347L retina is a formal proof of metabolic variability in the present in degenerating retina. Although retinal degeneration is certainly the trigger, Müller cell metabolic alterations are not a coherent response to the microenvironment. And while GS is believed to be the primary enzyme responsible for the conversion of glutamate to glutamine in the retina, alternative pathways appear to be unmasked in degenerating retina. Somehow, long term remodeling involves loss of Müller cell coordination and identity, which has negative implications for therapeutic interventions that target neurons alone.
authors.affiliation: Dept of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA. Electronic address: R.Pfeiffer@utah.edu.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Pfeiffer
authors.affiliation: Dept of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Marc
authors.affiliation: Department of Ophthalmology, Mie University Graduate School of Medicine, Tsu, Japan.
authors.forename: Mineo
authors.initials: M
authors.lastname: Kondo
authors.affiliation: Department of Ophthalmology, Nagoya University, Graduate School of Medicine, Nagoya, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Terasaki
authors.affiliation: Dept of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA.
authors.forename: Bryan W
authors.initials: BW
authors.lastname: Jones
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D004195:Disease Models, Animal; D063928:Ependymoglial Cells / Q000378:metabolism* / Q000473:pathology; D009457:Neuroglia / Q000378:metabolism* / Q000473:pathology; D010641:Phenotype; D011817:Rabbits; D012162:Retinal Degeneration / Q000378:metabolism / Q000473:pathology*
keywords: Computational molecular phenotyping (CMP); Müller cell; Retina; Retinal degeneration; Retinal remodeling; Retinitis pigmentosa (RP)