PROTEOMIC ANALYSIS OF SPINAL CORD INJURY AFTER TREATMENT WITH CEMENTUM-ATTACHMENT PROTEIN-DERIVED PEPTIDE (HACD1/CAP)

Abstract

Introduction: Spinal cord injury (SCI) represents a significant public health challenge, with an estimated 17,000 new cases annually in the United States and 2,000 cases in Mexico. Despite the profound psychological and social impact, current therapies do not promote spinal cord regeneration.
Our research group has developed an intralesional implant based on a peptide derived from the cementum-binding protein HACD1/CAP. This treatment is combined with hydrazide to reduce reactive oxygen species (ROS) and inflammation, along with debridement to eliminate hemorrhagic necrosis. In preclinical testing in a mouse model, the treatment resulted in significant motor recovery and increased survival rates.
However, the molecular mechanisms behind these improvements remain unclear.
Objective: To elucidate the biological mechanism of action of the treatment by analyzing proteomic changes in a mouse spinal cord injury after treatment implantation. Methodology: The study involved generating a traumatic spinal cord injury in mice. 24 hours later, the injured area was debrided and treatment was implemented. Five days later, we obtained spinal cord biopsies from the different groups: healthy spinal cord (control), untreated spinal cord injury (control), and spinal cord injury with our treatment (experimental) to perform protein extraction and proteomic analysis by liquid chromatography-mass spectrometry. The identified proteins were analyzed using the UNIPROT database, and interaction maps were developed in STRING, as well as the interpretation of biological process networks.
Result: In the experimental group, clusters related to neuronal regeneration, nervous system development, plasticity, synapses, and decreased inflammation and reactive oxygen species (ROS) were observed. These clusters were enhanced thanks to the peptide's properties, such as chemoattraction, cell proliferation, and differentiation. The debridement technique is important for generating a favorable microenvironment at the injured site for the regenerative process. Hydrazide reduces the expression of ROS and inflammation-related proteins, and finally, the peptide induces the expression of proteins related to nervous system development.
Conclusion: The proteomic study provided valuable information on the treatment's mechanism of action. It appears to promote motor recovery by facilitating nerve regeneration, improving myelination, and reducing inflammation and oxidative stress, processes essential for spinal cord repair.

Keywords: Traumatic spinal cord injury, regeneration, HACD1/CAP, hydrazide, oxidative stress