AGE-DEPENDENT NETWORK EXCITABILITY UPON BTKI ADMINISTRATION IN THE EAE MOUSE MODEL

Bruton’s tyrosine kinase (BTK) is a central signaling intermediary in immune pathways associated with Multiple Sclerosis (MS). Central nervous system–penetrant BTK inhibitors (BTKi) are being developed to modulate neuroinflammatory disease activity. How prophylactic BTK-treatment modulates neuronal population activity and network recruitment thresholds, across age groups, remains insufficiently characterized.
This study aims to assess whether prophylactic BTKi treatment modifies ex vivo neuronal network excitability in experimental autoimmune encephalomyelitis (EAE) and to establish an age-comparative framework in young and aged mice.
Young (8 weeks) and aged (10 months) mice received prophylactic BTKi treatment beginning from immunization through EAE development. Acute brain slices were prepared for multielectrode array (MEA) recordings. A standardized protocol was applied: baseline recording, stepwise increases in extracellular KCl (5 mM, 7.5 mM) and 4-aminopyridine (4-AP) as a positive control for robust network activation. Outcomes included firing rate, burst structure, and network synchrony. Analyses for the aged cohort are ongoing.
BTKi-treated EAE networks exhibited greater recruitment at 7.5 mM KCl, with consistently higher firing and bursting, indicating increased depolarization sensitivity under moderate stimulation. All groups responded robustly to 4-AP, confirming preserved capacity for strong network activation.
Prophylactic BTKi treatment is associated with enhanced network recruitment under moderate depolarizing stimulation in young EAE mice, indicating an inverse correlation between symptomatic burden and network excitability. Ongoing age-stratified analyses will test whether aging modifies this treatment-related shift in network excitability and will guide mechanistic follow-up on whether altered responsiveness reflects changes in synaptic excitation–inhibition balance or indirect effects of immunomodulation.