Interaction of microglia and amyloid-β through β2-integrin is regulated by RhoA

Amyloid-β (Aβ) is one of the main factors to cause Alzheimer's disease. Although fibrillar Aβ (fAβ) activates microglial cells that release toxic compounds to induce partial neuronal death, the mechanism of interaction between Aβ and microglia remains unclear. Therefore, we examined the interaction of microglial cells (BV2) and fAβ on a gelatin-precoated plate.The binding was markedly enhanced by RhoA inactivation using Tat-C3, dominant negative RhoA, and si-RhoA. To identify the receptor for fAβ, we tested various antibodies to mask receptors. Among them, anti-β2-integrin antibody mostly suppressed cell binding to fAβ.The incremental binding of cells induced by RhoA inhibition was also blocked by addition of anti-β2-integrin antibody. These results suggest that RhoA inhibition stimulates β2-integrin-mediated cell interaction to fAβ.