Neutrophil-specific exocytosis inhibitors for neuroinflammation in multiple sclerosis

Overview

Neutrophils are key drivers of central nervous system (CNS) inflammation in autoimmune and viral neuroinflammatory diseases, including experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS). This solution offers a class of small-molecule inhibitors, known as Nexinhibs, that selectively block neutrophil exocytosis, preventing the release of pro-inflammatory cargoes that drive tissue damage and demyelination. These are the only neutrophil-specific exocytosis inhibitors currently available, representing a novel therapeutic approach that targets neutrophil-mediated inflammation without broadly suppressing immune function or affecting encephalitogenic T cell responses.

The inhibitors have shown encouraging results in preclinical models, including decreased neutrophil activation, reduced tissue infiltration, and lower systemic pro-inflammatory cytokine production. In a viral-induced CNS demyelination model, preliminary data suggest a reduction in demyelination. The proposed research will evaluate these inhibitors in EAE, with the goal of reducing neutrophil infiltration into the CNS and limiting demyelination, offering a potential new pathway for treating MS and related neuroinflammatory conditions.

Technical specifications

Key features:

• First-in-class neutrophil-specific exocytosis inhibitors (Nexinhibs), including second-generation compounds designed for improved potency
• Selective mechanism targeting neutrophil secretion without affecting T cell-mediated immune responses
• Small-molecule format suitable for pharmaceutical development and oral or injectable administration
• Validated in endotoxemia and auto-inflammatory disease models, with ongoing evaluation in viral CNS infection models

Mechanism of action:

• Blocks the release of pro-inflammatory cargoes from neutrophils, reducing tissue infiltration and activation
• Decreases upregulation of adhesion and activation markers on neutrophils
• Reduces neutrophil-microglia interactions in the CNS, a key driver of neuroinflammation

Research tools and methods:

• CyTOF (mass cytometry) for detailed immune cell profiling
• Flow cytometry for quantifying neutrophil populations and activation states
• High-resolution microscopy for assessing neutrophil infiltration, microglia contact, and demyelination
• Luxol fast blue (LFB) staining for myelin quantification
• Brain drug concentration analysis to confirm CNS penetration

Technology readiness level

The Nexinhib inhibitors are at an early preclinical stage of development. They have been validated in vitro and in vivo across multiple inflammation models, with statistically significant results in an endotoxemia model (n=6, showing decreased pro-inflammatory cytokines) and an auto-inflammatory model (n=3, showing reduced tissue infiltration and activation marker expression). Preliminary data from a viral CNS infection model (n=6) suggest decreased demyelination, though expanded studies are needed to reach statistical significance.

Planned validation includes testing in the EAE mouse model using C57BL/6J mice with MOG35-55 induction, with approximately 15 mice per group to achieve adequate statistical power. Two small-molecule candidates will be evaluated for their ability to reduce neutrophil infiltration and demyelination in the CNS. Additional funding is required for animal studies, reagents, advanced analytical tools, and key personnel to complete this validation. The technology is positioned for translational development through Scripps Research's integrated drug discovery capabilities, including medicinal chemistry optimization and preclinical pathways.