Temporal-Specific Sex and Injury-Dependent Changes on Neurogranin-Associated Synaptic Signaling After Controlled...

Area of Science:

• Neuroscience
• Traumatic Brain Injury Research
• Synaptic Plasticity

Background:

• Cognitive impairment following traumatic brain injury (TBI) is linked to synaptic deficits.
• Neurogranin (Ng) is crucial for synaptic plasticity via calcium/calmodulin-dependent protein kinase II (CaMKII) signaling.
• Understanding Ng's role in post-TBI hippocampal synaptic changes is critical.

Purpose of the Study:

• To investigate alterations in hippocampal post-synaptic signaling proteins after controlled cortical impact (CCI) injury in rats.
• To examine the expression of Neurogranin (Ng) and associated proteins sub-acutely after TBI.

Main Methods:

• Adult male and female Sprague-Dawley rats underwent sham or CCI TBI under isoflurane anesthesia.
• Hippocampal synaptosomes were isolated at 24 hours, and 1, 2, and 4 weeks post-injury.
• Western blot analysis was used to assess protein expression of Ng, phosphorylated Ng, CaMKII, and CaM.

Main Results:

• Significant changes in hippocampal synaptic expression of Ng and associated proteins were observed up to 4 weeks post-CCI.
• Phosphorylated Ng, CaMKII, and CaM levels were altered, indicating TBI-induced synaptic dysfunction.
• These alterations were consistent across both sexes.

Conclusions:

• Traumatic brain injury significantly alters hippocampal synaptic signaling, including the expression and phosphorylation of Ng and related proteins.
• These synaptic changes contribute to cognitive deficits observed sub-acutely after TBI.
• The findings provide insight into the molecular mechanisms underlying TBI-related cognitive impairment.