Streptozotocin induced hyperglycemia stimulates molecular signaling that promotes cell cycle reentry in mouse hippocampus.

AIMS: Cerebral atrophy resulting from neurodegeneration is highly prevalent in individuals with diabetes; however, the underlying mechanisms for diabetic neurodegeneration are not fully understood. Here we hypothesized that hyperglycemia induces molecular signaling that favors induction of proliferation in post mitotic, fully differentiated hippocampal neurons.

MATERIALS AND METHODS: Streptozotocin (150 mg/kg) was intraperitoneally injected to four months old male mice to induce diabetes. Hippocampal tissue was subjected to molecular analysis of wingless-related integration site, extracellular signal regulated kinase, and brain derived neurotrophic factor signaling, and cell cycle regulation.

KEY FINDINGS: Hyperglycemia did not alter wingless-related integration site signaling or cyclin E levels in the hippocampus. There were reductions in extracellular signal regulated kinase activation and brain derived neurotrophic factor levels along with elevated cyclin D1 levels.

SIGNIFICANCE: These findings indicate that hyperglycemic conditions can stimulate cell cycle progression in the hippocampus in vivo. These new insights into the disease mechanisms could support the development of novel therapeutics aimed to provide neuroprotection in diabetic patients.