The retinal pigment epithelium (RPE) ensures different functions crucial for photoreceptor survival, and thus for vision, such as photoreceptor outer segments (POS) phagocytosis and retinal adhesion. Both follow a circadian rhythm with an activity peak occurring respectively 1.5-2 and 3.5 h after light onset. Interestingly, we showed that two rodent models, β5-/- and Prpf31+/- mice, display distinct alterations in both functions leading to different phenotypes. Indeed, the phagocytic peak totally disappears in β5 knockout mice but is attenuated and shifted in Prpf31+/- mice. Conversely, the retinal adhesion peak only attenuated in β5-/- mice is lost in Prpf31+/- mice. These distinct alterations have different consequences on retinal homeostasis proportional to the observed defects: β5-/- mice progressively lose vision and accumulate RPE lipofuscin deposits, while Prpf31+/- mice develop RPE metabolic dysfunctions and gradual structural modifications indicative of cellular stress. Hence, animal models are useful to understand the importance of the proper regulation of these functions.
Keywords: Animal models; Beta5 integrin; Circadian clock; Metabolism; Phagocytosis; Photoreceptor outer segments; Prpf31; Retinal adhesion; Retinal pigment epithelium.
© 2023. The Author(s), under exclusive license to Springer Nature Switzerland AG.