Pfeiffer Rebecca L, Marc Robert E, Kondo Mineo, Terasaki Hiroko, Jones Bryan W
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.
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.
Exp Eye Res. 2016 Sep;150:62-70. doi: 10.1016/j.exer.2016.04.022. Epub 2016 Apr 30.
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.
缪勒细胞在视网膜代谢中起着关键作用，并且是最早在视网膜应激或疾病中表现出代谢变化的细胞之一。这些变化的时间、程度、调节和影响尚不清楚。我们评估了退化视网膜中缪勒细胞的代谢表型。从野生型（WT）和视紫红质Tg P347L兔子采集的视网膜用混合醛固定并树脂包埋，用于计算分子表型分析（CMP）。CMP有助于对视网膜中的每个细胞进行小分子指纹识别，从而能够评估单个细胞中的代谢物水平。CMP揭示了来自TgP347L视网膜的缪勒细胞之间代谢物水平的特征性差异。简而言之，相邻的缪勒细胞在牛磺酸、谷氨酸、谷氨酰胺、谷胱甘肽、谷氨酰胺合成酶（GS）和CRALBP方面表现出变异性。这种变异性在代谢物之间没有相关性，这意味着这些变化在功能上是混乱的，而不仅仅是异质性的。在TgP347L视网膜中，任何聚类算法都无法将缪勒细胞分类为单一类别，这正式证明了退化视网膜中存在代谢变异性。虽然视网膜退化肯定是触发因素，但缪勒细胞的代谢改变并非对微环境的一致反应。而且，虽然GS被认为是视网膜中负责将谷氨酸转化为谷氨酰胺的主要酶，但在退化的视网膜中似乎揭示了替代途径。不知何故，长期重塑涉及缪勒细胞协调性和特性的丧失，这对仅针对神经元的治疗干预具有负面影响。
