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小鼠光感受器代谢改变导致晚期年龄相关性黄斑变性样病变。

Altered photoreceptor metabolism in mouse causes late stage age-related macular degeneration-like pathologies.

机构信息

Department of Ophthalmology and Visual Sciences, University of Massachusetts Medical School, Worcester, MA 01655.

Department of Ophthalmology and Visual Science, Yale School of Medicine, New Haven, CT 06510.

出版信息

Proc Natl Acad Sci U S A. 2020 Jun 9;117(23):13094-13104. doi: 10.1073/pnas.2000339117. Epub 2020 May 20.

Abstract

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly. While the histopathology of the different disease stages is well characterized, the cause underlying the progression, from the early drusen stage to the advanced macular degeneration stage that leads to blindness, remains unknown. Here, we show that photoreceptors (PRs) of diseased individuals display increased expression of two key glycolytic genes, suggestive of a glucose shortage during disease. Mimicking aspects of this metabolic profile in PRs of wild-type mice by activation of the mammalian target of rapamycin complex 1 (mTORC1) caused early drusen-like pathologies, as well as advanced AMD-like pathologies. Mice with activated mTORC1 in PRs also displayed other early disease features, such as a delay in photoreceptor outer segment (POS) clearance and accumulation of lipofuscin in the retinal-pigmented epithelium (RPE) and of lipoproteins at the Bruch's membrane (BrM), as well as changes in complement accumulation. Interestingly, formation of drusen-like deposits was dependent on activation of mTORC1 in cones. Both major types of advanced AMD pathologies, including geographic atrophy (GA) and neovascular pathologies, were also seen. Finally, activated mTORC1 in PRs resulted in a threefold reduction in di-docosahexaenoic acid (DHA)-containing phospholipid species. Feeding mice a DHA-enriched diet alleviated most pathologies. The data recapitulate many aspects of the human disease, suggesting that metabolic adaptations in photoreceptors could contribute to disease progression in AMD. Identifying the changes downstream of mTORC1 that lead to advanced pathologies in mouse might present new opportunities to study the role of PRs in AMD pathogenesis.

摘要

年龄相关性黄斑变性(AMD)是老年人致盲的主要原因。虽然不同疾病阶段的组织病理学特征已经很好地描述,但导致疾病进展的原因,从早期的玻璃膜疣阶段到导致失明的晚期黄斑变性阶段,仍然未知。在这里,我们表明,患病个体的感光细胞(PRs)显示出两种关键糖酵解基因的表达增加,表明在疾病过程中存在葡萄糖短缺。通过激活雷帕霉素靶蛋白复合物 1(mTORC1)模拟 PRs 中的这种代谢特征,导致早期的玻璃膜疣样病变以及晚期 AMD 样病变。在 PRs 中激活 mTORC1 的小鼠还表现出其他早期疾病特征,例如感光细胞外节(POS)清除延迟以及视网膜色素上皮(RPE)和 Bruch 膜(BrM)中脂褐素和脂蛋白的积累,以及补体积累的变化。有趣的是,玻璃膜疣样沉积物的形成依赖于锥体中 mTORC1 的激活。包括地图状萎缩(GA)和新生血管病变在内的两种主要类型的晚期 AMD 病变也都存在。最后,PRs 中激活的 mTORC1 导致含有二-docosahexaenoic 酸(DHA)的磷脂种类减少三倍。用富含 DHA 的饮食喂养小鼠可缓解大多数病理变化。这些数据重现了人类疾病的许多方面,表明感光细胞的代谢适应可能导致 AMD 疾病进展。确定 mTORC1 下游导致小鼠晚期病变的变化可能为研究 PRs 在 AMD 发病机制中的作用提供新的机会。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/252a/7293639/0e28af870aa5/pnas.2000339117fig01.jpg

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