Gliptins normalize posttraumatic hippocampal neurogenesis and restore cognitive function after controlled cortical...

Area of Science:

• Neuroscience
• Cell Biology
• Pharmacology

Background:

• Traumatic brain injury (TBI) frequently causes lasting neurocognitive deficits.
• Adult neurogenesis in the hippocampal dentate gyrus (DG) is crucial for cognition but vulnerable to brain insults.
• Disrupted neurogenesis and astrocyte reactivity in the DG contribute to TBI-related cognitive impairments.

Purpose of the Study:

• To investigate the effects of DPP-4 inhibitors (gliptins) on hippocampal function and cognitive sequelae following TBI.
• To explore the cellular and molecular mechanisms underlying gliptin's neuroprotective effects in a TBI model.

Main Methods:

• A controlled cortical impact (CCI) model of moderate TBI was used in mice.
• Sitagliptin and vildagliptin were administered to assess their impact on neurogenesis, astrocyte activation, and cognitive behavior.
• Electrophysiological recordings evaluated long-term potentiation in DG immature granule cells.

Main Results:

• Sensorimotor CCI induced cognitive deficits, increased DG neurogenic proliferation, reactive astrocytes, and ectopic immature neurons.
• Gliptins (sitagliptin, vildagliptin) reduced ectopic migration of immature neurons and normalized dendritic outgrowth.
• DPP-4 inhibitors preserved synaptic integration, prevented astrocyte reactivation, and improved cognitive performance post-TBI.

Conclusions:

• Distal sensorimotor cortical injury disrupts hippocampal neurogenesis and astrocyte function, contributing to cognitive decline.
• DPP-4 inhibitors mitigate these detrimental effects by normalizing neurogenesis and astrocyte activity.
• Gliptins offer a potential therapeutic strategy for improving cognitive outcomes after TBI.