Study On The Anti-inflammatory Mechanism Of Curcumin Inhibiting APOE4-mediated Neuroinflammation

Objective: To explore the effect of curcumin on APOE4-induced neuroinflammation and its molecular mechanism,it is expected to provide a new therapeutic target for AD.Methods:(1)In vivo,APOE4 gene knock in mice was selected as Alzheimer's disease(AD)model mice,and DNA was extracted from mouse tail tissue,which was identified as positive mice by PCR.APOE4 gene knock in mice and C57BL/6 mice were divided into four groups.Curcumin was given to the curcumin administration group(APOE4-KI + Cur)and curcumin control group(WT + Cur)for 21 days in a continuous manner by intraperitoneal injection.The wild control group(WT)and the gene knock-in group(APOE4-KI)were given corresponding solvents in the same way.At the end of an administration,water maze experiment was carried out.Nissl staining was used to observe the changes of the hippocampal morphology of mice;Tumor necrosis factor(TNF-?),interleukin 1?(IL-1?)and NO inflammatory factors were detected by ELISA;Inducible carbon monoxide synthase(i NOS)and cyclooxygenase 2(COX-2)proteins were immunofluorescence Detection;Western Blot was used to detect the expression of NF-?Bp65,p-NF-?Bp65,and peroxisome proliferator-activated receptor ?(PPAR?)protein in brain tissue.(2)In vitro experiments,MTT was used to detect the survival rate of cells after transfection;Ed U method was used to detect the proliferation of SHSY5 Y cells;ELISA method was used to detect the release of pro-inflammatory factors;Immunofluorescence method was used to detect the nuclear entry of NF-?Bp65;Immunoblotting was used to detect the inflammatory factors Expression of i NOS,COX-2 protein and NF-?B signaling pathway related protein.For further in-depth study,down-regulate PPAR? protein and analyze the effect on NF-?B signaling pathway protein.Results: Curcumin can inhibit APOE4-mediated inflammatory damage both in vivo and invitro.(1)The results of water maze showed that compared with wild-type mice,APOE4 gene knockin mice increased their swimming trajectory,prolonged escape latency,decreased time,distance and times of crossing the platform in target quadrant,suggesting that the spatial sense and learning and memory ability of mice were impaired;Nissl staining results showed that APOE4 gene knock-in mice had significantly reduced Nissl bodies,scattered cell arrangement,and curcumin could significantly reverse the injury;second,the release of inflammatory factors TNF-?,IL-1?,and NO was significantly inhibited by curcumin;Immunofluorescence results also showed that curcumin inhibited i NOS and COX-2 protein expression;immunoblotting results showed that curcumin can inhibit NF-?B signaling pathway and promote PPAR?protein expression.(2)In SHSY5 Y cells transfected with APOE4,curcumin significantly reduced the release of inflammatory factors TNF-?,IL-1?,and NO;Western Blot results showed that under the stimulation of APOE4,curcumin can reduce the total NF-?Bp65 and nucleus in cells p-NF-?Bp65expression;in addition,APOE4 overexpression inhibits PPAR? and significantly reduces its expression,while curcumin can reverse and increase the expression of PPAR? protein;The application of inhibitors GW9662 and PPAR? sh RNA technology to downregulate PPAR? protein expression and observe The expression of total NF-?Bp65 in the treated cells and p-NF-?Bp65 in the nucleus increased significantly compared with curcumin administration,suggesting that PPAR? is involved in the regulation of NF-?B signaling pathway.Conclusions: Curcumin inhibits APOE4-mediated inflammation and damage in vivo and in vitro.The mechanism may be that curcumin plays an anti-inflammatory role by activating PPAR? protein,thereby regulating the NF-?B signaling pathway.