PEG-PEI/siROCK2 inhibits A beta(42)-induced microglial inflammation via NLRP3/caspase 1 pathway

Objectives There is an urgent need to develop therapeutic strategies to improve the treatment outcome of Alzheimer's disease. The treatment strategy of gene therapy mediated by nanocarrier systems brings new hope for the treatment of Alzheimer's disease. ROCK2 is involved in various pathological processes of Alzheimer's disease and may be a potential target for the treatment of Alzheimer's disease. Our previous study indicated that PEG-PEI/siROCK2 [polyethyleneglycol-polyethyleneimine deliver ROCK2-siRNA, (PPSR)] prevented A beta(42)-induced neurotoxicity and showed a promising prospect for the treatment of Alzheimer's disease. However, whether PPSR has an effect on the microglial inflammation in Alzheimer's disease is still unclear. Materials and methods 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay was used to detect the cytotoxicity of PEG-PEI and PPSR in primary microglial cells. Real-time PCR and western blotting were used to assess the expression of ROCK2 and nucleotide oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3)/caspase 1 pathway in primary microglial cells. ELISA assay was used to measure the effect of PPSR on attenuating the lipopolysaccharide (LPS) + A beta-induced increase in IL-1 beta. Results PEG-PEI concentration less than 20 mu g/ml and the N/P (molar ratio of PEG-PEI amino/siRNA phosphate) ratio of PPSR less than 50 showed no significant cytotoxicity in primary microglia cells. PPSR could effectively inhibit the expression of ROCK2 in primary microglial cells. A further study revealed that PPSR attenuates the LPS+A beta-induced increase in IL-1 beta without affecting cell viability. In addition, we found that PPSR suppressed the A beta-induced NLRP3/caspase 1 pathway in primary microglial cells. Conclusion PPSR inhibits A beta(42)-induced microglial inflammation via NLRP3/caspase 1 pathway.