Hugo Oyamada, Yinzhi Ying, Sudhanshu Agrawal, Aizhu Liu, Veedamali S Subramanian, Cleonice Alves de Melo Bento, Anshu Agrawal
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引用次数: 0
Abstract
Neuroinflammation is a key contributor to the onset and progression of neurodegenerative diseases, driven by factors such as viral infections, autoimmune disorders, and peripheral inflammation. However, the mechanisms linking peripheral inflammation or viral infections to neuroinflammation remain poorly understood, limiting the development of effective therapies. Proinflammatory cytokines are implicated in these processes but their effects on brain cells, including microglia, remain insufficiently characterized. Here, we demonstrate that IL-21, a proinflammatory cytokine elevated in autoimmune disorders, chronic viral infections, and Alzheimer's disease, activates microglia and promotes lipid accumulation within these cells. Young, healthy mice injected with IL-21 to mimic chronic exposure exhibited increased proinflammatory cytokine levels and microglial activation in the brain. Notably, microglia in these mice displayed enhanced lipid accumulation, accompanied by upregulation of lipid uptake receptors such as CD36 and TREM-2. These findings were corroborated using the human microglial cell line HMC-3, where IL-21 exposure similarly induced lipid accumulation and increased expression of CD36 and ApoE. Mechanistic investigations revealed that IL-21 upregulates HIF-1α, a transcription factor critical for lipid metabolism and lipid droplet formation. Additionally, we observed elevated IL-21 levels in the circulation of elderly individuals compared to younger counterparts, with IL-21 increases associated with CMV seropositivity. Aged mouse brains mirrored the microglial lipid accumulation and activation patterns seen in IL-21-injected mice. In summary, we identify a novel IL-21-driven mechanism involving lipid accumulation in microglia that contributes to neuroinflammation.
期刊介绍:
Immunity & Ageing is a specialist open access journal that was first published in 2004. The journal focuses on the impact of ageing on immune systems, the influence of aged immune systems on organismal well-being and longevity, age-associated diseases with immune etiology, and potential immune interventions to increase health span. All articles published in Immunity & Ageing are indexed in the following databases: Biological Abstracts, BIOSIS, CAS, Citebase, DOAJ, Embase, Google Scholar, Journal Citation Reports/Science Edition, OAIster, PubMed, PubMed Central, Science Citation Index Expanded, SCImago, Scopus, SOCOLAR, and Zetoc.