Roflumilast Elicits Therapeutic and Neuroprotective Effects in 3-Nitropropionic Acid-Induced Huntington’s Disease-Like Neurodegeneration in Rats by Mitigating NLRP3 Inflammasome-Mediated Pyroptosis, Ferroptosis, and Glial Activation
摘要
Huntington’s disease (HD) pathogenesis involves diverse cellular mechanisms, yet the contributions of pyroptosis and ferroptosis remain elusive. Roflumilast, a phosphodiesterase-4 (PDE-4) inhibitor, has shown neuroprotective effects, but its precise mechanisms are yet to be elucidated. We evaluated the potential neuroprotective and therapeutic effects of roflumilast in 3-nitropropionic acid (3-NP)-induced HD-like neurodegeneration, focusing on pyroptotic and ferroptotic cell death signaling. Adult male Wistar rats were assigned to five groups: normal control (saline + 0.5% carboxymethyl cellulose), roflumilast-control (1 mg/kg/day, p.o. for 21 days), 3-NP (20 mg/kg/day, i.p. for seven days), roflumilast-prophylactic (1 mg/kg/day, p.o. for 21 days prior to 3-NP), and roflumilast-treatment (1 mg/kg/day, p.o. for 21 days post-3-NP). Behavioral outcomes of the open-field, rotarod, and grip strength tests were assessed. Striatal PDE-4, total and p-CREB, BDNF, interleukin-1β, and markers of pyroptosis (NLRP3, caspase-1, and gasdermin D) and ferroptosis (iron, GPx4, GSH, and malondialdehyde) were measured alongside histopathological alterations and GFAP and Iba-1 immunohistochemical staining. Bioinformatics was used to visualize the target genes’ protein-protein interaction network. Behavioral assessments revealed impaired locomotion, motor coordination, and muscle strength in the 3-NP-injected rats. Biochemical analysis showed increased striatal PDE-4 expression and decreased p-CREB/BDNF axis alongside NLRP3 inflammasome/caspase-1/gasdermin D activation and elevated interleukin-1β. In parallel, ferroptosis was evidenced by increased striatal iron and malondialdehyde levels, along with reduced GPx4 and GSH. Histopathological examination revealed pronounced striatal neurodegeneration, accompanied by enhanced GFAP and Iba-1 immunostaining, indicating astrogliosis and microglial activation. Roflumilast, administered prophylactically or therapeutically, significantly improved functional and behavioral abnormalities while ameliorating biochemical, histopathological, and immunohistochemical derangements induced by 3-NP. The therapeutic regimen exhibited superior efficacy relative to prophylaxis. Conclusively, roflumilast exerts therapeutic and neuroprotective effects in HD-like neurodegeneration by mitigating pyroptosis and ferroptosis, attenuating astrogliosis, microglial activation, and neuroinflammation, and restoring synaptic plasticity.
Graphical AbstractA graphical abstract illustrating the proposed mechanistic pathway underlying the neuroprotection of the PDE-4 inhibitor roflumilast through reducing striatal pyroptosis, ferroptosis, microglial and astrocyte activation, and neuroinflammation, while restoring synaptic plasticity in experimental Huntington’s disease-like neurodegeneration induced by 3-NP.