The retina: Considerations regarding cell diversity, structure, and mouse modelling in neurodegeneration.

Degeneration of the retina is of extreme importance, as conditions such as retinitis can cause blindness. In addition, the retina can be considered a window into the central nervous system and is garnering increasing interest in the clinical management of neurodegeneration, as it allows fast, accessible and non-invasive monitoring of patients with diverse neurodegenerative conditions. Importantly, this tissue has the potential not only to share but sometimes to precede most of the etiopathogenic mechanisms that occur in inaccessible inner brain areas. In this review, we provide an overview of retinal architecture and function, combined with novel findings in single-cell transcriptomics that support the ample cellular heterogeneity across layers. Because mice are the most popular models for neurodegeneration research, it is important to understand precisely the similarities and differences with humans to enable a precise translation of the discoveries made in mice to patients. Finally, we extend these considerations to neuroinflammatory and autoimmune mouse models, highlighting how common degenerative mechanisms support the role of the retina as an accessible proxy for brain disorders.