1256493-34-1

Dynamin is a large GTPase enzyme that severs membrane‐bound clathrin‐coated vesicles. Endocytosis internalizes portions of cells’ plasma membrane along with extracellular material, is fundamentally important in cell physiology. Hydroxy Dynasore inhibits Dynamin I (Dyn I) activity with IC ₅₀ values of 2.7 μM and 0.38 μM with or without 0.06% Tween‐80 in the GTPase assay. Hydroxy Dynasore shows an IC ₅₀ of 5.7 μM in clathrin‐mediated endocytosis (CME) assay for inhibition of Tfn‐A594 uptake in U2OS cells. Hydroxy Dynasore shows IC ₅₀ values of 0.38 μM and 1.1 μM in absence of Tween-80, and exhibits IC ₅₀ values of 4.9 μM and 30.0 μM in presence of Tween-80, respectively. Hydroxy Dynasore is 2.1‐fold selective for DynI versus DynII from Sf21 cells] and DynII (recombinant protein from Sf21 cells) in this GTPase assay. Hydroxy Dynasore prevents the uptake of BoNT/A-Hc in cultured hippocampal neurons and in motor nerve terminals. Hydroxy Dynasore (1-100μM; 20 min prior to the addition of Alexa Fluor 488-BoNT/A-Hc) results in depolarization of Hippocampal neurons, it dose-dependently inhibits internalization of Alexa Fluor 488-BoNT/A-Hc with an IC ₅₀ of 16.0 ± 1.2 μM.

Hydroxy Dynasore (intraperitoneal injection; 30 mg/kg; 1.5-2 h before BoNT/A injection) provides protection again BoNT/A-induced paralysis in the phrenic nerve-hemidiaphragm twitch model in CD-1 mice.