Autophagy regulates Müller glial cell inflammatory activation

ABSTRACT: Purpose. Immune privilege in the eye is a compilation of anti-inflammatory mechanisms that protect vision from the damaging sequelae of intense immune responses. Although the breakdown of privilege can lead to ocular disease, little is known about how these mechanisms are regulated. Since retinal Müller glial cells and autophagy also have anti-inflammatory properties, we tested the idea that Müller cells utilize autophagy to support immune privilege. Methods. The essential autophagy regulator Atg5 was deleted in retinal Muller cells using a tamoxifen inducible GlastCre ERT X Atg5f/f strain. Intraocular inflammation was induced by intravitreal injection of LPS and monitored by H&E staining, immunofluorescent confocal microscopy, and flow cytometry. scRNA-seq was performed on retinal Müller cells isolated from control and Atg5-deficient mice. Additionally, markers of Müller cell gliosis and function were assessed by western blotting and cytokines were detected by Luminex cytokine/chemokine arrays. In cultured Müller cells siRNA knockdown techniques were used to examine the role of autophagy in regulation of LPS-induced inflammatory pathways. Results. We observed increased and prolonged intraocular inflammation when Müller cells were autophagy (Atg5) deficient. Müller cell gliosis (as measured by Gfap expression) was significantly increased and inflammation was sustained over 5 days post-LPS injection compared to control. The retinae with Atg5-deficient Müller cells also contained increased inflammatory mediators and neuroprotective molecules. Gene expression analysis revealed a heterogeneous response to LPS in Müller glial cell population that revealed 2 states of activation. The normal retinae contain Müller cells in both a basal and an activated state, while autophagy deficient retinae (Atg5iΔMüller) contained only activated Müller cells. Analysis of gliosis markers Gfap and Lcn2 confirmed this heterogeneity showing that in control eyes basal and activated (gliotic) Müller glia were observed; however, with autophagy deficiency nearly all Müller cells were gliotic. Interestingly, activated cells were largely indistinguishable between autophagy sufficient and deficient Müller cells. In cultured Müller cells, siRNA knockdown of autophagy genes resulted in heightened mTOR activation, increased Gfap expression, and upregulated cytokine/chemokine production. Conclusions. Autophagy deficiency in Müller cells leads to enhanced intraocular inflammation though activation of the mTOR pathway. Our data suggests that autophagy defines a novel perspective on Müller glial heterogeneity based on their activation state. Thus, autophagy restrains cellular activation and inflammation, supporting immune privilege by preventing excessive and potentially destructive immune responses.

ORGANISM(S): Mus musculus

PROVIDER: GSE293132 | GEO | 2025/09/10

REPOSITORIES: GEO