A selective p38α/β MAPKs inhibitor alleviates neuropathology and cognitive impairment by modulating microglia function in 5XFAD mouse
Abstract Background: Chronic neuroinflammation, aggressive amyloid beta (Aβ) deposition, neuronal cell loss and cognitive impairment are pathological symptoms of Alzheimer’s disease (AD). Regarding these symptoms, resolution of neuroinflammation and inhibition of Aβ-driven pathology might be one of the important strategies for AD therapy. Previous efforts to prevent AD progression have identified that p38 mitogen-activated protein kinase (MAPK) is a promising target for AD therapy. Especially, recent studies showed that pharmacological p38α MAPK inhibition improved memory impairment in AD mouse models. Methods: In this study, we explored the therapeutic potential of NJK14047, a selective p38α/β MAPKs inhibitor, using an Alzheimer’s disease mouse model, 5XFAD. The mice were injected 2.5 mg/kg NJK14047 or vehicle every other day for 3 months. Morris water maze task and histological imaging analysis were performed. Protein and mRNA expression levels were measured using immunoblotting and qRT-PCR respectively. In in vitro studies, the cytotoxicity of microglial conditioned medium and astrocyte conditioned medium on primary neurons were measured using MTT assay and TUNEL assay. Results: NJK14047 treatment downregulated phospho-p38 MAPK levels, decreased the amount of Aβ deposits, and prevented spatial learning memory loss in 9-month-old 5XFAD mice. Interestingly, we found the decreased pro-inflammatory conditions and increased expression of alternatively activated microglial markers and microglial phagocytic receptors. Furthermore, NJK14047 treatment reduced the number of Fluoro-jade B positive cells, a class of degenerating neurons, in the brains of 5XFAD mice. The neuroprotective effect of NJK14047 was further confirmed by in vitro studies. Conclusion: Taken together, a selective p38α/β MAPKs inhibitor NJK14047 successfully showed therapeutic effects in 5XFAD mice. Our data support that p38 MAPKs inhibition is a potential strategy for AD therapy and NJK14047 might be one of the promising candidates for AD therapeutics targeting p38 MAPKs.