Acute Extrinsic Activation of the RANKL Pathway Decreases Wound Healing and Functional Recovery After Spinal Cord Injury in Mice.

Manipulating wound healing-associated signaling after SCI presents a promising avenue for increasing the recovery of function after injury. This study explores the potential of targeting molecular regulators of wound healing, initially identified in nonneural tissues, to enhance outcomes after SCI. Astrocytes, pivotal in central nervous system wound healing, play a crucial role in tissue remodeling and recovery. However, the optimal manipulation of astrogliosis for beneficial outcomes remains elusive. Previous research demonstrated a transcriptional response in astrocytes resembling epithelial-to-mesenchymal transitions (EMTs) after CNS injury. Here, we investigate the extrinsic manipulation of wound healing through the Receptor Activator of Nuclear-factor Kappa-Β (RANK) pathway, known for its involvement in nonneural tissue remodeling and linked to EMT pathway. Using a severe thoracic spinal cord contusion mouse model, we demonstrate that acute activation of the RANK pathway with RANK ligand (RANKL) adversely affects tissue remodeling, resulting in larger lesion volumes and delayed recovery of posture and locomotion. These findings suggest that early perturbations in the tight molecular regulation of tissue remodeling negatively impact the wound-healing process after SCI. The study provides a proof-of-concept demonstration that exogenous nonneural remodeling ligands can modify astrocyte responses and functional recovery after SCI, raising questions about the optimal time frame for beneficial remodeling interventions during injury progression. These insights open new avenues for therapeutic strategies aimed at improving functional outcomes following SCI.