A new study published in Burns & Trauma identifies a key molecular pathway that turns spinal cord scars from a barrier to repair into a target for therapeutic intervention. Fibrotic scarring is a major obstacle to recovery after spinal cord injury (SCI). While initial scar formation helps stabilize the wound, excessive fibrosis later creates a dense barrier that blocks axon regrowth and limits functional recovery. The study, conducted by researchers from multiple Chinese institutions, reveals that the c-Jun–Irf8–CD36 axis drives this scarring process and that inhibiting CD36 or its upstream regulator c-Jun can reduce fibrotic scar formation, improve vascular remodeling, support axonal regeneration, and promote motor recovery in mouse models.
Using single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics, the team mapped CD36 expression after SCI and found it concentrated in lesion scars, particularly in specific fibroblast subclusters associated with fibrotic progression. To test therapeutic potential, they used salvianolic acid B (SAB), a CD36 inhibitor, and T5224, an AP-1/c-Jun inhibitor, in mouse SCI models. SAB reduced P4HB-positive fibroblast accumulation, decreased fibrotic deposition, enhanced CD31-marked angiogenesis, supported axonal regrowth, and improved hindlimb functional recovery. T5224 similarly lowered CD36 expression, reduced fibroblast aggregation and extracellular matrix (ECM) deposition, promoted vascular remodeling, and improved early motor recovery.
Mechanistically, the study demonstrated that c-Jun activates Irf8, which then promotes CD36 transcription, establishing a c-Jun–Irf8–CD36 signaling cascade. CUT&Tag and dual-luciferase reporter assays confirmed this regulatory connection. Multi-omic analyses further showed that T5224 selectively restrained the abnormal expansion of CD36-positive fibroblast subclusters and shifted their transcriptional state toward a less fibrotic, more repair-permissive phenotype.
The authors suggest that rather than trying to remove scar tissue completely, the goal may be to tune the scar at the right stage—preserving its early protective role while preventing fibroblasts from building a long-lasting fibrotic wall. Identifying c-Jun, Irf8, and CD36 as connected control points provides a clearer route for developing therapies that reshape the injury microenvironment and give regenerating axons a better chance to reconnect.
These findings may support new stage-adapted strategies for SCI treatment, especially therapies aimed at scar biology during the early post-injury window. Because both CD36 and c-Jun are pharmacologically targetable, the work provides a foundation for testing localized drug delivery, combination therapy, or precision approaches that act on pathogenic fibroblast subtypes while preserving tissue stability. The study also shows how scRNA-seq and spatial transcriptomics can reveal not only which cells are present in an injury site, but where they act and how they change after treatment. Further validation in larger animal models and preclinical systems will be needed before translation to human SCI therapy.
The full study is available at https://doi.org/10.1093/burnst/tkag020.
