Effect And Mechanism Of β Amyloid Protein On Mouse Macrophage Cell Line RAW264.7

Objective: Alzheimer’s disease(AD)is a neurodegenerative disease characterized by the presence of β-amyloid protein(Aβ)in the brain.The senile plaques formed by sedimentation and neurofibrillary tangles in nerve cells due to abnormal phosphorylation of Tau protein are generally accompanied by activation of intracerebral inflammatory response and neural stem cell function.The AD inflammatory response is mainly caused by microglia in the brain,astrocytes,peripheral monocytes that cross the blood-brain barrier,and secretion of inflammatory cytokines and chemokines [1].In the AD brain,the inflammatory response is inextricably linked to its development.The peripheral blood mononuclear cells of AD patients and brain-injected Aβ rats highly expressed the granulocyte-macrophage colony-stimulating factor(GM-CSF)receptor βsubunit-CSF2 RB,There was no significant difference in the expression of CSF2RA(GM-CSF receptor alpha subunit)between patients and the elderly of the same age.The above results suggest that the difference in expression of CSF2 RA and CSF2 RB is associated with Aβ inflammation in the brain.Mononuclear cells differentiate into macrophages after entering the brain.To investigate the effect of Aβ on macrophage GM-CSF receptor expression and macrophage function,we stimulated mouse macrophages with Aβ1-42 synthetic peptide in vitro.The cell line RAW264.7 was compared with the LPS stimulation results to study the effect and mechanism of Aβ1-42 on the expression and secretion of inflammatory factors in RAW264.7 cells.Methods: RAW264.7 cells were stimulated by LPS and Aβ1-42 and the expression levels of GM-CSF receptors CSF2 RA and CSF2 RB were detected by RT-PCR and Western Blot.The inflammatory factors GM-CSF 、IL-1β、IL-6 and TNF-α levels were detected by ELISA under Aβ1-42 stimulation.TLR4 inhibitors were used to intervene in RAW264.7 cells treated with LPS and Aβ1-42 and detect changes in CSF2 RA and CSF2 RB receptor expression,and release of inflammatory factors IL-1β and IL-6.Flow cytometry was used to detect the differentiation type of RAW264.7 cells stimulated by Aβ1-42.Results: The expression of GM-CSF receptor CSF2 RA and CSF2 RB on RAW264.7 cells increased after LPS and Aβ1-42 treatment,and CSF2 RA increased before CSF2 RB, which was significantly different from the control group(p<0.05);Inflammation factor IL-6 and IL-1β increase after Aβ1-42 stimulation,TLR4 plays a role in the release of Aβ-induced inflammatory factors.Conclusion:1.Aβ1-42/LPS stimulation of macrophage RAW264.7 increased CSF2 RA and CSF2 RB,and CSF2 RA increased before CSF2 RB.2.Aβ1-42 increases the secretion of macrophage inflammatory factors IL-1β and IL-6 through the action of the TLR4 receptor.