Insulin deficiency promotes formation of toxic amyloid-β42 conformer co-aggregating with hyper-phosphorylated tau oligomer in an Alzheimer's disease model.

The toxic conformer of amyloid β-protein (Aβ) ending at 42 (Aβ42), which contains a unique turn conformation at amino acid residue positions 22 and 23 and tends to form oligomers that are neurotoxic, was reported to play a critical role in the pathomechanisms of Alzheimer's disease (AD), in which diabetes mellitus (DM)-like mechanisms are also suggested to be operative. It remains to be established whether the attenuation of insulin signaling is involved in an increase of toxic Aβ42 conformer levels. The present study investigated the association between impaired insulin metabolism and formation of toxic Aβ42 conformers in the brains of an AD mouse model.

Apomorphine Therapy for Neuronal Insulin Resistance in a Mouse Model of Alzheimer's Disease.

Apomorphine (APO) promotes intraneuronal amyloid-β (Aβ) degradation and improves memory function in an Alzheimer's disease (AD) model, 3xTg-AD mice. Since insulin resistance is increased in AD neurons, we investigated the effects of APO on brain insulin resistance in 3xTg-AD mice at early and late stages. After 1-month subcutaneous injection of Apokyn® to 3xTg-AD mice at 6 or 12 months of age, memory function was significantly improved in both age groups.

Activation of glutathione peroxidase and inhibition of p53-related apoptosis by apomorphine.

Apomorphine hydrochloride (APO) is known to be a dopamine receptor agonist, and has recently been found to be a novel drug for Alzheimer's disease (AD). We found that APO treatment ameliorated oxidative stress in an AD mouse model and specifically attenuated the hydrogen peroxide-induced p53-related apoptosis in the SH-SY5Y neuroblastoma cell line. To further understand the mechanism behind this action, we investigated the actions of APO on intracellular redox systems, such as the glutathione cycle and catalase.