Dataset Information

Autophagy activation and photoreceptor survival in retinal detachment.

ABSTRACT: We assess the effect of autophagy inhibition on photoreceptor (PR) survival during experimental retinal detachment (RD) and examine the and examine the relationship between autophagy and the expression of glycolytic enzymes HK2 and PKM2 in the retina. We find that inhibiting autophagy by genetic knock out of the autophagy activator Atg5 in rod PRs resulted in increased apoptotic and necroptotic cell death during RD, demonstrated by elevated terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells, caspase 8 activity, transcript levels of Fas receptor and RIPK3 as compared to controls. The absence of autophagy in rods resulted in downregulation of hexokinase 2 and pyruvate kinase muscle isozyme 2 levels. More than 460 proteins were identified by mass spectroscopy in autophagosomes isolated from detached retinas compared with less than 150 proteins identified in autophagosomes from attached retinas. Among various cellular compartments, proteins from cytoskeleton, cytoplasm and intracellular organelles constituted a large portion of increased autophagosome contents. These proteins represent numerous biological processes, including phototransduction, cell-cell signaling, metabolism and inflammation. Our findings suggest that competent autophagy machinery is necessary for PR homeostasis and improving PR survival during periods of nutrient deprivation.

SUBMITTER: Xiao J

PROVIDER: S-EPMC8043966 | biostudies-literature | 2021 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Autophagy activation and photoreceptor survival in retinal detachment.

Xiao Jianhui J Yao Jingyu J Jia Lin L Ferguson Thomas A TA Weber Sarah S Sundstrom Jeffrey M JM Wubben Thomas J TJ Besirli Cagri G CG Zacks David N DN

Experimental eye research 20210218

We assess the effect of autophagy inhibition on photoreceptor (PR) survival during experimental retinal detachment (RD) and examine the and examine the relationship between autophagy and the expression of glycolytic enzymes HK2 and PKM2 in the retina. We find that inhibiting autophagy by genetic knock out of the autophagy activator Atg5 in rod PRs resulted in increased apoptotic and necroptotic cell death during RD, demonstrated by elevated terminal deoxynucleotidyl transferase dUTP nick end lab ...[more]

PMID: 33609513

Similar Datasets

Project description:PurposePhotoreceptor (PR) death is the ultimate cause of irreversible vision loss in retinal detachment (RD). Although microglial infiltration in the subretinal space (SRS) was observed after RD, the molecular mechanism underlying microglial activation and the outcomes of infiltrating microglia remain unclear. We aimed to uncover the mechanism of initiation of microglial activation to help explore potential therapy to promote PR survival.MethodsAn RD model was conducted by injecting sodium hyaluronate into SRS of C57BL/6J wild type mice. Adenosine triphosphate (ATP) was measured by a ATP Microplate Assay Kit. Bioinformatics analysis was used to evaluate the upregulated receptor relating to ATP binding in human datasets and mouse transcriptomes of RD. Expression of P2X7, its downstream signaling pathways, and microglial pyroptosis were confirmed by qPCR, WB, and immunofluorescence in vivo and in vitro. The cell viability of PR was measured by cell counting kit-8. Brilliant Blue G, a P2X7 antagonist, was subretinally or intraperitoneally injected to inhibit microglial activation in vivo and was applied for microglia cell line treatment in vitro. The decrease in microglial activation and pyroptosis was detected by immunofluorescence and WB. The protective effect on PR was measured by hematoxylin and eosin staining, TUNEL assay, and electroretinogram analysis.ResultsThe results showed that extracellular ATP released in the SRS after RD triggered P2X7 activation and attracted microglia. The downstream cascade of inflammasome activation induced by P2X7 activation contributed to microglial pyroptosis and then to PR death. ATP-activated microglia led to PR death in vitro. P2X7 blockade rescued PR morphologically and functionally by inhibiting microglial activation and pyroptosis.ConclusionsThese results elucidate that ATP-induced P2X7-mediated microglial activation leads to microglial pyroptosis, contributing to PR death. Appropriate inhibition of microglial pyroptosis might serve as a pharmacotherapeutic strategy for decreasing PR death in RD.

Project description:Retinal detachment is a sight-threatening disorder, which occurs when the photoreceptors are separated from their vascular supply. The aim of the present study was to shed light on photoreceptor energy metabolism during experimental detachment in rats. Retinal detachment was induced in the eyes of rats via subretinal injection of sodium hyaluronate. Initially, we investigated whether detachment caused hypoxia within photoreceptors, as evaluated by the exogenous and endogenous biomarkers pimonidazole and HIF-1α, as well as by qPCR analysis of HIF target genes. The results showed no unequivocal staining for pimonidazole or HIF-1α within any detached retina, nor upregulation of HIF target genes, suggesting that any reduction in pO2 is of insufficient magnitude to produce hypoxia-induced covalent protein adducts or HIF-1α stabilisation. Subsequently, we analysed expression of cellular bioenergetic enzymes in photoreceptors during detachment. We documented loss of mitochondrial, and downregulation of glycolytic enzymes during detachment, indicating that photoreceptors have reduced energetic requirements and/or capacity. Given that detachment did not cause widespread hypoxia, but did result in downregulated expression of bioenergetic enzymes, we hypothesised that substrate insufficiency may be critical in terms of pathogenesis, and that boosting metabolic inputs may preserve photoreceptor bioenergetic production and, protect against their degeneration. Thus, we tested whether supplementation with the bioavailable energy substrate pyruvate mitigated rod and cone injury and degeneration. Despite protecting photoreceptors in culture from nutrient deprivation, pyruvate failed to protect against apoptotic death of rods, loss of cone opsins, and loss of inner segment mitochondria, in situ, when evaluated at 3 days after detachment. The regimen was also ineffective against cumulative photoreceptor deconstruction and degeneration when evaluated after 4 weeks. Retinal metabolism, particularly the bioenergetic profiles and pathological responses of the various cellular subtypes still presents a considerable knowledge gap that has important clinical consequences. While our data do not support the use of pyruvate supplementation as a means of protecting detached photoreceptors, they do provide a foundation and motivation for future research in this area.

Dataset Information

Autophagy activation and photoreceptor survival in retinal detachment.

Publications

Autophagy activation and photoreceptor survival in retinal detachment.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets