Involvement of insulin signalling pathway in methamphetamine-induced hyperphosphorylation of Tau

Methamphetamine (METH), an amphetamine-like drug, is one of the most commonly used central nervous system psychostimulants worldwide. METH abuse frequently leads to cognitive decline and dementia-like changes, but the mechanisms remain poorly understood. In the present study, the mechanisms of METH-induced changes in Alzheimer's disease-like pathological protein in Neuro2A cells were explored. Our results indicated that METH exposure significantly increased the expression of the pathological protein hyperphosphorylated tau (p-tau). Further analysis revealed that METH exposure obviously disrupted insulin signalling, resulted in brain insulin resistance, which manifested as downregulation of the insulin receptor substrate-1, AKT^{ser 473}, and GSK3β activation. Notably, the linkage between p-tau expression and insulin signalling can be partially verified by treatment with the insulin-sensitizing drug rosiglitazone and GSK3β inhibitor TWS119 which specifically reversed METH-induced hyperphosphorylation of tau. Our results indicate that insulin signalling can be therapeutically exploited for attenuating METH-induced upregulation of p-tau.