Peripheral nervous system (PNS) neurons, including motor neurons (MNs), possess a remarkable ability to regenerate and reinnervate target muscles following nerve injury. This process is orchestrated by a combination of intrinsic neuronal properties and extrinsic factors, with Schwann cells (SCs) playing a central role. Upon injury, SCs transition into a repair phenotype that allows axonal regeneration through molecular signaling and structural guidance. However, the identity of the SCs’ reprogramming factors is only partially known. We previously identified hydrogen peroxide (H₂O₂) as an early and key driver of nerve repair, inducing gene expression rewiring in SCs to support nerve re-growth. In this study, we quantitatively assessed the role of H₂O₂ in the activation of key pro-regenerative signaling pathways in SCs following sciatic nerve compression, specifically the extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun, which are essential for functional nerve recovery. Notably, we found that H₂O₂ neutralization does not impact degeneration, but it significantly affects the regenerative response. Collectively, our findings establish H₂O₂ as a promising regulator of the Schwann cell injury response at the injury site, linking oxidative signaling to the molecular mechanisms governing nerve regeneration.

Instability and denervation of the neuromuscular junction (NMJ) are early events in Amyotrophic Lateral Sclerosis (ALS), likely reflecting a progressive decline in the regenerative capacity of motor neurons (MNs) and their environment. To investigate this, we evaluated NMJ regeneration throughout disease progression in SOD1 ^G93A mice following reversible axon terminal degeneration induced by α-Latrotoxin. In parallel, we monitored the expression of CXCR4, a GPCR upregulated during axonal regeneration, and tested whether its pharmacological activation could mitigate ALS- related functional decline. We found that NMJ regenerative capacity is largely preserved during pre- and early symptomatic stages, and remains active in subsets of NMJs even at later stages. CXCR4 is expressed at axon terminals from early disease stages, declining only at end stage. Its expression is conserved across ALS models, including SOD1 ^G93A pigs, hiPSC-derived MN with ALS mutations, and biopsies from sporadic ALS patients. CXCR4 stimulation improved motor function, NMJ innervation, MN survival, and respiratory performance in ALS mice, and axon outgrowth in iPSC-derived MN. These findings identify the NMJ and CXCR4 as viable therapeutic targets in ALS.