Pleiotropic Roles of Scavenger Receptors in Circadian Retinal Phagocytosis: A New Function for Lysosomal SR-B2/LIMP-2 at the RPE Cell Surface - Inserm - Institut national de la santé et de la recherche médicale Access content directly
Journal Articles International Journal of Molecular Sciences Year : 2022

Pleiotropic Roles of Scavenger Receptors in Circadian Retinal Phagocytosis: A New Function for Lysosomal SR-B2/LIMP-2 at the RPE Cell Surface

Abstract

The retinal phagocytic machinery resembles the one used by macrophages to clear apoptotic cells. However, in the retina, the permanent contact between photoreceptor outer segments (POS) and retinal pigment epithelial (RPE) cells requires a tight control of this circadian machinery. In addition to the known receptors synchronizing POS internalization, several others are expressed by RPE cells. Notably, scavenger receptor CD36 has been shown to intervene in the internalization speed. We thus investigated members of the scavenger receptor family class A SR-AI and MARCO and class B CD36, SR-BI and SR-B2/LIMP-2 using immunoblotting, immunohisto- and immunocytochemistry, lipid raft flotation gradients, phagocytosis assays after siRNA/antibody inhibition, RT-qPCR and western blot analysis along the light:dark cycle. All receptors were expressed by RPE cell lines and tissues and colocalized with POS, except SR-BI. All receptors were associated with lipid rafts, and even more upon POS challenge. SR-B2/LIMP-2 inhibition suggested a role in the control of the internalization speed similar to CD36. In vivo, MARCO and CD36 displayed rhythmic gene and protein expression patterns concomitant with the phagocytic peak. Taken together, our results indicate that CD36 and SR-B2/LIMP-2 play a direct regulatory role in POS phagocytosis dynamics, while the others such as MARCO might participate in POS clearance by RPE cells either as co-receptors or via an indirect process.
Fichier principal
Vignette du fichier
Rieu 2022 IJMS scavenger receptors RPE phago.pdf (7.88 Mo) Télécharger le fichier
Origin Publication funded by an institution

Dates and versions

inserm-03814298 , version 1 (13-10-2022)

Licence

Identifiers

Cite

Quentin Rieu, Antoine Bougoüin, Yvrick Zagar, Jonathan Chatagnon, Abdallah Hamieh, et al.. Pleiotropic Roles of Scavenger Receptors in Circadian Retinal Phagocytosis: A New Function for Lysosomal SR-B2/LIMP-2 at the RPE Cell Surface. International Journal of Molecular Sciences, 2022, 23 (7), pp.3445. ⟨10.3390/ijms23073445⟩. ⟨inserm-03814298⟩
24 View
36 Download

Altmetric

Share

Gmail Mastodon Facebook X LinkedIn More