Abstract
Sleep and emotional disturbances are prevalent in systemic lupus erythematosus (SLE) patients, yet the neuroinflammatory mechanisms remain unclear. Here, we investigated this issue using pristane-induced lupus (PIL) mice. We firstly confirmed that PIL mice exhibited progressive fragmentation of NREM sleep and decreased cumulative sleep time, correlating with blood-brain barrier (BBB) leakage and IgG deposition in the paraventricular thalamus (PVT). Concurrently, PVT neurons showed aberrant excitatory activity, including a high level of cFos expression, decreased amplitude and increased rate of Ca2+ transients during wakefulness. Bulk RNA sequencing and protein analyses demonstrated upregulation of the cyclic GMP-AMP synthase (cGAS) -stimulator of interferon genes (STING) -TANK-binding kinase 1 (TBK1) activation pathway in PVT microglia, with elevated phosphorylation of STING (pSTING) and TBK1 (pTBK1), promoting synthesis of pro-inflammatory cytokines. Selectively knockdown STING in microglia effectively normalized PVT neuronal excitability, restored sleep homeostasis, and ameliorated anxiety/depression-like behaviors. Notably, we identified selective expression of cannabinoid receptor type 2 (CB2R) in PVT microglia. Pharmacological CB2R activation could inhibit TBK1 phosphorylation, attenuate microglial inflammatory responses, and improve sleep and emotional disturbances. Our findings elucidate a novel neuroimmune axis in SLE-related neuropsychiatric symptoms, offering potential therapeutic avenues for mitigating neuroinflammation and associated behavioral comorbidities in lupus.