Journal of neurotrauma
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Journal of neurotrauma · Jul 2019
Multifocal Neuronal Ultrastructural Abnormalities and Synaptic Alterations in Mice after Low-Intensity Blast Exposure.
Service members during military actions or combat training are exposed frequently to primary blast generated by explosive weaponry. The majority of military-related neurotrauma are classified as mild and designated as "invisible injuries" that are prevalent during current conflicts. While the previous experimental blast injury studies using moderate- to high-intensity exposures focused mainly on gross and microscopic neuropathology, our previous studies have shown that low-intensity blast (LIB) exposures resulted in nanoscale subcellular myelin and mitochondrial damages and subsequent behavioral disorders in the absence of gross or detectable cellular damage. ⋯ In addition, we observed a significant increase in protein levels of PSD95 and synaptophysin mainly at seven DPI indicating potential synaptic reorganization. These results demonstrated that a single LIB exposure can lead to ultrastructural brain injury with accompanying multi-focal neuronal organelle alterations. This pre-clinical study provides key insights into disease pathogenesis related to primary blast exposure.
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Journal of neurotrauma · Jul 2019
A Role for Postsynaptic Density 95 and its Binding Partners in Models of Traumatic Brain Injury.
Postsynaptic density 95 (PSD-95), the major scaffold protein at excitatory synapses, plays a major role in mediating intracellular signaling by synaptic N-methyl-d-aspartate (NMDA) type glutamate receptors. Despite the fact that much is known about the role of PSD-95 in NMDA-mediated toxicity, less is known about its role in mechanical injury, and more specifically, in traumatic brain injury (TBI). Given that neural circuitry is disrupted after TBI and that PSD-95 and its interactors end-binding protein 3 (EB3) and adenomatous polyposis coli (APC) shape dendrites, we examined whether changes to these proteins and their interactions occur after brain trauma. ⋯ Rapid deformation of cortical neurons leads to neuronal death 72 h after injury, but this outcome is not dependent on PSD-95 expression. However, disruptions in dendritic arborization following stretch injury in vitro require PSD-95 expression, and these changes in arborization can be mimicked with expression of PSD-95 mutants lacking the second PDZ domain. Thus, PSD-95 and its interactors may serve as therapeutic targets for repairing dendrites after TBI.