NHR-85 modulates mitochondrial and lipid homeostasis to protect against α-synuclein aggregation in <i>C. elegans</i>

Peroxisome proliferator-activated receptors (PPARs), such as PPARδ, are transcription factors that play a pivotal role in energy and fat metabolism. PPARδ activates genes involved in lipid and glucose metabolism and is expressed in various human tissues, including all brain regions and especially neurons, where it regulates lipid homeostasis and contributes to neuroprotection. However, the precise molecular mechanisms underlying these protective effects remain poorly understood. Here, we identify the Caenorhabditis elegans nuclear hormone receptor NHR-85 as a putative orthologue of human PPARδ. Furthermore, we show that NHR-85 functions as an essential regulator of fat and energy metabolism, with significant impact on mitochondrial homeostasis, at least in part through modulation of mitophagy. Finally, we find that NHR-85 prevents α-synuclein aggregation in a nematode model of Parkinson's disease, suggesting that it might play a protective role in neurodegenerative diseases. Our results indicate that NHR-85 is a functional orthologue of PPARδ and support the use of C. elegans as a powerful in vivo model for dissecting PPARδ-related metabolic and neurodegenerative processes.