Netrin-3 enhances recovery and reduces inflammation following spinal cord injury via suppressing NLRP1 inflammasome activation

Spinal cord injury (SCI) represents a significant challenge in the field of neurology due to its complex pathology and the limited efficacy of current treatments. The search for effective therapeutic strategies has led to investigations into molecules that can promote neural repair and functional recovery. Netrin-3, previously known for its roles in axonal guidance and development, emerges as a potential candidate for enhancing recovery post-SCI. Hereby, we used gene therapy to increase Netrin-3 expression in SCI mouse models and evaluated neurological recovery through behavioral tests, histological assessments, and biochemical analyses. Additionally, we examined the activation of the NOD-like Receptor family pyrin domain containing 1 (NLRP1) inflammasome and production of interleukin-1β (IL-1β) and IL-18, and confirmed the dependency of Netrin-3's neuroprotective effects on the Adenosine Monophosphate-activated Protein Kinase (AMPK) pathway using an AMPK Inhibitor. Our results explores the impact of Netrin-3 on neurological recovery following SCI. It was observed that Netrin-3 expression markedly decreased at both mRNA and protein levels after injury. Enhancing Netrin-3 levels through gene therapy improved neurological outcomes, including locomotor function, reduced lesion size, and normalized spinal cord water content compared to untreated injured mice. Furthermore, Netrin-3 administration mitigated oxidative stress by modulating malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity, and inhibited NLRP1 inflammasome activation, resulting in suppressed IL-1β and IL-18 production. The AMPK pathway was activated by Netrin-3 post-injury, suggesting a mechanism underlying its neuroprotective effects. However, these beneficial impacts were abolished by an AMPK Inhibitor, indicating the dependency of Netrin-3's protective actions on the AMPK pathway. Collectively, these findings highlight Netrin-3 as a promising target for developing novel therapies aimed at improving restoration from SCI.

AMPK; NLRP1; Netrin-3; Oxidative stress; Spinal cord injury.