2-Cyclopropylimino-3-methyl-1,3-thiazoline hydrochloride protects against beta-amyloid-induced activation of the apoptotic cascade in cultured cortical neurons.

Aggregated β-amyloid, implicated in the pathogenesis of Alzheimer's disease (AD), induces neurotoxicity by evoking a cascade of oxidative damage-dependent apoptosis in neurons. We investigated the molecular mechanisms underlying the protective effect of 2-cyclopropylimino-3-methyl-1,3-thiazoline hydrochloride (KHG26377) against the beta-amyloid (Aβ25-35)-induced primary cortical neuronal cell neurotoxicity. Treatment with KHG26377 attenuated the Aβ25-35-induced apoptosis by decreasing the Bax/Bcl-2 ratio and suppressing the activation of caspase-3. A marked increase in calcium influx and in the level of reactive oxygen species together with a decrease in glutathione levels was found after Aβ25-35 exposure; however, KHG26377 treatment reversed these changes in a concentration-dependent manner. In addition, KHG26377 significantly suppressed Aβ25-35-induced toxicity concomitant with a reduction in the activation of extracellular signal-regulated kinases 1 and 2 and nuclear factor kappa B. The KHG26377-induced protection of neuronal cells against Aβ toxicity was also mediated by suppressing the expression of glycogen synthase kinase-3β, increasing the levels of β-catenin, and reducing the levels of phosphorylated tau. Our findings suggest that KHG26377 may modulate the neurotoxic effects of β-amyloid and provide a rationale for treatment of AD.