Cross-Species Transcriptomic Analysis Identifies an Endocannabinoid-Associated Immune Remodeling Signature and Candidate Pharmacologic Targets in Spinal Cord Injury

Background: Spinal cord injury (SCI) triggers secondary injury processes involving neuroinflammation and systemic immune remodeling. The endocannabinoid system (ECS) has been implicated in neuroimmune regulation, but its transcriptional relationship with immune remodeling and its translational relevance in human SCI blood remain incompletely defined. Methods: A cross-species discovery–validation–translation framework was applied using a rat spinal cord discovery cohort (GSE45006), an independent mouse validation cohort (GSE171441), and a human peripheral white blood cell cohort (GSE151371). Analyses included differential expression profiling, ECS-focused assessment, cross-species comparison, immune-cell signature scoring, ECS–immune correlation analysis, receiver operating characteristic (ROC) analysis, LASSO-based biomarker prioritization, network analysis, disease enrichment, drug–gene interaction querying, and transcription factor/microRNA regulatory annotation. Results: ECS-related transcriptional remodeling was identified across rodent and human datasets in a compartment-dependent manner. In human SCI blood, CNR2, PTGS2, and DAGLB were significantly altered and showed biomarker-prioritization potential. Human SCI blood also showed innate immune enrichment, adaptive immune depletion, and significant ECS–immune correlations. The integrated 28-gene SCI–ECS immune panel formed a functionally coherent protein–protein interaction (PPI) network enriched in immune-response pathways. Disease enrichment supported an immune/inflammatory pathological context, whereas DGIdb identified hypothesis-generating drug–gene relationships involving ECS-related targets. ChEA 2022 revealed nominal transcription factor annotations that did not survive multiple-testing correction, and miRNet identified database-derived miRNA regulators of panel genes. In a secondary sensitivity analysis, the combined ECS signature also retained discriminatory performance against non-CNS trauma controls, suggesting that the observed transcriptional pattern was not fully attributable to generalized trauma-related responses. Conclusions: This study proposes an ECS-associated immune remodeling signature in SCI with translational biomarker-prioritization and pharmacologic target-annotation context in human peripheral blood. These findings are exploratory and require prospective and functional validation.