Metcalf ISCIENCE-D-23-07458R1_N2_reverse

Glia are the protectors of the nervous system, providing neurons with support and protection from cytotoxic insults. We previously discovered that four astrocyte-like glia can regulate organismal proteostasis and longevity in C. elegans. Expression of the UPRER transcription factor, XBP-1s, in these glia increases stress resistance, longevity, and activates the UPRER in intestinal cells via neuropeptides. Autophagy, a key regulator of metabolism and aging, has been described as a cell autonomous process. Surprisingly, we find that glial XBP-1s enhances proteostasis and longevity by cell non-autonomously reprogramming organismal lipid metabolism and activating autophagy. Glial XBP-1s regulates the activation of another transcription factor, HLH-30/TFEB, in the intestine. HLH-30 activates intestinal autophagy, increases intestinal lipid catabolism, and upregulates a robust transcriptional program. Our study reveals a novel role for glia in regulating peripheral lipid metabolism, autophagy, and organellar health through peripheral activation of HLH-30 and autophagy

神经胶质细胞（Glia）是神经系统的保护者，可为神经元提供支持并使其免受细胞毒性损伤。我们此前的研究发现，秀丽隐杆线虫（C. elegans）体内的4类星形胶质样神经胶质细胞可调控机体蛋白质稳态与寿命。在这类胶质细胞中表达内质网未折叠蛋白反应（UPRER）转录因子XBP-1s，可提升机体应激抗性与寿命，并通过神经肽激活肠道细胞的内质网未折叠蛋白反应。自噬（autophagy）作为调控代谢与衰老的关键因子，此前被认为是一种细胞自主性过程。令人意外的是，本研究发现胶质细胞中的XBP-1s可通过细胞非自主性重编程机体脂质代谢、激活自噬，进而提升机体蛋白质稳态与寿命。胶质细胞XBP-1s可调控肠道内另一转录因子HLH-30/TFEB的激活。HLH-30可激活肠道自噬、促进肠道脂质分解代谢，并上调一套强效的转录程序。本研究揭示了神经胶质细胞通过外周激活HLH-30与自噬，进而调控外周脂质代谢、自噬与细胞器健康的全新功能。