Neuro-Stabilizing Proteolytic Activating Chimeras (N-SPARCs): A Non-Immunomodulatory Paradigm for Targeted Neuroprotection in Multiple Sclerosis

This manuscript introduces an innovative, non-immunomodulatory therapeutic class for Multiple Sclerosis (MS) called Neuro-Stabilizing Proteolytic Activating Chimeras (N-SPARCs). This approach aims to address the shortcomings of current treatments, which rely on systemic immune suppression. An N-SPARC is a biologic prodrug designed to be inert in the body but capable of crossing the blood-brain barrier to access the central nervous system. It is selectively activated only within active MS lesions, where pathologically high levels of a destructive enzyme, Matrix Metalloproteinase-9 (MMP-9), are present. This enzyme cleaves a specific linker in the drug's structure, releasing a potent therapeutic payload—an inhibitory peptide that neutralizes local MMP-9 activity at its source. This targeted mechanism is intended to achieve a threefold therapeutic effect: stabilizing the blood-brain barrier, protecting the myelin sheath from damage, and attenuating the neurotoxic environment, all without affecting the immune system in the rest of the body. The manuscript also addresses potential challenges such as activation specificity, immunogenicity, and manufacturing, and it proposes a clear research roadmap for proof-of-concept validation, presenting a promising new therapeutic paradigm for MS.