FRAX486

FRAX486 is a potent p21-activated kinase (PAK) inhibitor (IC50 values are 14, 33, 39 and 575 nM for PAK1, PAK2, PAK3 and PAK4 respectively) . FRAX486 rescues seizures and behavioral abnormalities such as hyperactivity and repetitive movements, thereby supporting the hypothesis that a drug treatment that reverses the spine abnormalities can also treat neurological and behavioral symptoms. A single administration of FRAX486 is sufficient to rescue all of these phenotypes in adult Fmr1 KO mice, demonstrating the potential for rapid, postdiagnostic therapy in adults with FXS. FRAX486 ameliorate schizophrenia-associated dendritic spine deterioration in vitro and in vivo during late adolescence. (In Vitro) :In vitro kinase assays using pure enzymes reveal IC50s for FRAX486 between 10-100 nM for PAK1-3, while the IC50 of 779 nM for PAK4 is just below the micromolar range. For FRAX486, an EC50 value of 500 nM has been reported from cells (5-50 fold higher than IC50) . FRAX486 (30 μM) inhibits endothelin-1 and -2 induced contractions. In WPMY-1 cells, FRAX486 (24 h) induces concentration-dependent (1-10 μM) degeneration of actin filaments. This is paralleled by attenuation of proliferation rate, being observed from 1 to 10 μM FRAX486. Cytotoxicity of FRAX486 in WPMY-1 cells is time- and concentration-dependent. FRAX486 significantly reduces the relative proliferation rate in the remaining populations of WPMY-1 cells. While 68% of solvent-treated (24 h) cells shows proliferation, proliferation rate after application of FRAX486 (1-10 μM, 24 h) ranges around 45%. FRAX486 (1-10 μM, 24 h) causes concentration-dependent degeneration of actin filaments. Actin filaments in solvent-treated control cells are arranged to bundles, forming long and thin protrusions, with elongations from adjacent cells overlapping each other. FRAX486 in concentrations of 1 μM causes partial loss of actin organization, including regressing degree of actin polymerization and degeneration of protrusions. FRAX486 in concentrations of 5 or 10 μM causes complete breakdown of filament organization, resulting in a rounded cell shape without protrusions. (In Vivo) :FRAX486 displays the highest penetrance of blood–brain barrier in DISC1-knockdown C57BL/6 mice. Daily administration of FRAX486, but not that of vehicle, between P35 and P60 blocks the exacerbated spine loss during adolescence. In addition to the significant blockade of spine elimination, a trend of enhanced spine generation is observed by treatment with FRAX486. FRAX486 treatment ameliorates a deficit in prepulse inhibition in adulthood.