Clearance of lipid droplets by chimeric autophagy-tethering compound ameliorates the age-related macular degeneration phenotype in mice lacking APOE

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness among the elderly, and there is currently no clinical treatment targeting the primary impairment of AMD. The earliest clinical hallmark of AMD is drusen, which are yellowish spots mainly composed of lipid droplets (LDs) accumulated under the retinal pigment epithelium (RPE). However, the potential pathogenic role of this excessive LD accumulation in AMD is yet to be determined, partially due to a lack of chemical tools to manipulate LDs specifically. Here, we employed our recently developed Lipid Droplets center dot AuTophagy Tethering Compounds (LD center dot ATTECs) to degrade LDs and to evaluate its consequence on the AMD-like phenotypes in apoe(-/-) (apolipoprotein E; B6/JGpt-Apoe(em1Cd82)/Gpt) mouse model. apoe(-/-) mice fed with high-fat diet (apoe(-/-)-HFD) exhibited excessive LD accumulation in the retina, particularly with AMD-like phenotypes including RPE degeneration, Bruch's membrane (BrM) thickening, drusen-like deposits, and photoreceptor dysfunction. LD center dot ATTEC treatment significantly cleared LDs in RPE/choroidal tissues without perturbing lipid synthesis-related proteins and rescued RPE degeneration and photoreceptor dysfunction in apoe(-/-)-HFD mice. This observation implied a causal relationship between LD accumulation and AMD-relevant phenotypes. Mechanically, the apoe(-/-)-HFD mice exhibited elevated oxidative stress and inflammatory signals, both of which were mitigated by the LD center dot ATTEC treatment. Collectively, this study demonstrated that LD accumulation was a trigger for the process of AMD and provided entry points for the treatment of the initial insult of AMD by degrading LDs.

Automated summary

Age-related macular degeneration (AMD) is a major cause of irreversible blindness in the elderly, and there is currently no clinical treatment specifically targeting its primary impairment. This study focuses on the excessive accumulation of lipid droplets (LDs) in AMD and its potential role in the development of the disease. The researchers utilized a new compound called LD center dot ATTEC to degrade LDs and observed a significant improvement in AMD-like phenotypes.