Comparative transcriptomic analysis of retinal response to diverse cellular stresses reveals relative contributions of different cell death processes and signalling networks

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Retinal degeneration comprises a diverse group of progressive disorders leading to visual impairment and ultimately blindness. These include inherited retinal dystrophies (IRDs), diabetic retinopathy (DR), age-related macular degeneration (AMD), and glaucoma, affecting millions worldwide. The underlying pathology involves dysfunction and death of photoreceptor cells and the retinal pigment epithelium (RPE), driven by various stress-induced cell death mechanisms. Although multiple pathways have been reported, the relative contribution of each remains incompletely understood, highlighting the need for further investigation. Therefore, we studied how different stress types that induce retinal degeneration alter the global gene expression profile in vivo (C57BL/6 mice), aiming to identify predominant cell death mechanisms as well as key genes and networks. Retinal toxicity was induced using established models of oxidative stress, hypoxia, endoplasmic reticulum (ER) stress, and chronic inflammation. Transcriptomic profiling revealed both unique and convergent gene expression changes associated with each stressor. In total, 170, 328, 146, and 151 genes were significantly altered under oxidative stress, inflammation, ER stress, and hypoxia, respectively (Log2 fold change >2 or <-2; p < 0.05). Genes such as Arhgap26, Ccdc9, Ube2e2, and Fndc3b were commonly dysregulated across ER stress, inflammation, and oxidative stress, whereas Nfix, Elp6, Naca, and Plcd3 were selectively altered in oxidative stress, inflammation, ER stress, and hypoxia, respectively. Analysis of cell death-related gene subsets revealed that pyroptosis was commonly activated across different stress types. Additionally, autophagy-mediated cell death, ferroptosis, and extrinsic apoptosis were preferentially associated with oxidative stress, chronic inflammation, and hypoxia, respectively. Both ER and oxidative stress models showed strong activation of autophagy-associated cell death. Together, these findings delineate distinct molecular signatures and predominant cell death mechanisms triggered by specific stressors, providing important insights that could aid in developing targeted therapies to prevent or slow retinal degeneration.

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