Integrated miRNA-proteomic profiling identifies chronic vesicle-trafficking and proteostasis disruptions after mild...

Mild traumatic brain injury (mTBI) often produces persistent deficits, yet the molecular mechanisms driving chronic pathology remain undefined.

We aimed to identify mechanistic drivers of long-term dysfunction after mTBI by integrating proteomics, transcriptomics, and behavioral outcomes.

Adult rats were subjected to a modified Marmarou weight-drop mTBI model (diffuse closed-head injury) or a sham procedure. Cortical tissue was analyzed at 21 days post-injury (chronic phase) by quantitative proteomics and small RNA sequencing, while neurological and motor functions were tracked longitudinally (subacute to chronic phases). Key molecular changes were validated via Western blotting and RT-qPCR.

mTBI induced widespread and persistent alterations in cortical protein expression, particularly affecting vesicle-trafficking and proteostasis-related pathways. Several proteins-including Rab11b, Dnm2, TIA1, Snx30, Sbf1, and Vma21-exhibited robust decreases across both proteomic and immunoblot analyses, indicating reproducible impairment of endosomal recycling and stress-response mechanisms. Cavin-2 and COMMD2 showed significant fold changes at the proteomic level but were not entirely validated and therefore remain preliminary observations. Differentially expressed miRNAs exhibited coordinated regulatory patterns, and integrated miRNA-protein signatures achieved high discriminatory performance (AUC > 0.95) in separating injured from control animals.

These findings demonstrate that even an mTBI causes enduring disruptions in protein homeostasis, vesicle trafficking, and post-transcriptional regulation, which correlate with chronic behavioral deficits. The injury-responsive networks identified provide a systems-level foundation for future mechanistic studies and highlight promising candidate biomarkers to improve mTBI diagnosis and monitoring.