Mitophagy in the Retinal Pigment Epithelium of Dry Age-Related Macular Degeneration Investigated in the NFE2L2/PGC-1α-/- Mouse Model.
Iswariyaraja Sridevi GurubaranJohanna ViiriAli KoskelaJuha M T HyttinenJussi J PaternoGréta KisMiklós AntalArto UrttiAnu KauppinenSzabolcs FelszeghyKai KaarnirantaPublished in: International journal of molecular sciences (2020)
Increased oxidative stress and mitochondrial damage are observed in protein aggregation diseases, such as age-related macular degeneration (AMD). We have recently reported elevated levels of oxidative stress markers, damaged mitochondria, accumulating lysosomal lipofuscin and extracellular drusen-like structures in the retinal pigment epithelial cells (RPE) of the dry AMD-resembling NFE2L2/PGC1α double knockout (dKO) mouse model. Here, we provide evidence of a disturbance in the autolysosomal machinery handling mitochondrial clearance in the RPE cells of one-year-old NFE2L2/PGC1α-deficient mice. Confocal immunohistochemical analysis revealed an upregulation of autophagosome marker microtubule-associated proteins 1A/1B light chain 3B (LC3B) as well as numerous mitophagy markers, such as PTE-induced putative kinase 1 (PINK1) and E3 ubiquitin ligase (PARKIN) together with damaged mitochondria. However, we detected no evidence of increased autolysosome formation in transmission electron micrographs or of colocalization of lysosomal marker LAMP2 (lysosome-associated membrane protein 2) and the mitochondrial marker ATP synthase β in confocal micrographs. Interestingly, we observed an upregulation of late autolysosomal fusion Ras-related protein (Rab7) in the perinuclear space of RPE cells together with autofluorescence aggregates. Our results reveal that there is at least a relative decrease of mitophagy in the RPE cells of NFE2L2/PGC1α dKO mice. This further supports the hypothesis that mitophagy is a putative therapy target in AMD-like pathology.
Keyphrases
- age related macular degeneration
- oxidative stress
- induced apoptosis
- mouse model
- diabetic rats
- skeletal muscle
- cell cycle arrest
- signaling pathway
- cell death
- endoplasmic reticulum stress
- dna damage
- ischemia reperfusion injury
- type diabetes
- cell proliferation
- stem cells
- single cell
- reactive oxygen species
- metabolic syndrome
- tyrosine kinase
- insulin resistance
- dna methylation
- mesenchymal stem cells
- binding protein
- data analysis
- high glucose