BRL-50481 is a novel and selective PDE7 inhibitor with IC50 values of 0.15 μM for PDE7A, 12.1 μM for PDE7B, 62 μM for PDE4, and 490 μM for PDE3.

PDE7B:12 μM, PDE7A:0.15 μM, PDE3:490 μM, PDE4:62 μM

BRL-50481 marginally increases cAMP levels (19.1±6.2% of the IBMX response at 300 μM) but demonstrates lower potency. At a concentration of 30 μM, BRL-50481 does not independently hinder proliferation but significantly enhances the efficacy of rolipram in this regard. Similarly, it does not affect IL-15-driven proliferation alone, yet amplifies rolipram’s inhibitory properties. A 30-minute pretreatment of human monocytes with BRL-50481 exhibits a minor inhibitory impact (~2 to 10%) on TNFα production across all examined concentrations but boosts the suppressive action of PGE2 on LPS-induced TNFα release. Alone, BRL-50481 has a negligible influence on κB-dependent transcription (5.6±1.9% inhibition at 30 μM) and does not bolster rolipram’s effectiveness (maximum inhibition, 52.9±2.7%; pIC30 value of 5.33±0.12). However, BRL-50481 dose-dependently curtails LPS-induced TNFα secretion in monocytes where PDE7A1 is elevated (21.7±1.6% inhibition at 30 μM after 12 hours) [2].

MOLT-4 cells in 96-well plates are treated for 30 min with BRL-50481. The cAMP content is then determined by an immuno-specific ELISA. Results are expressed as a percentage of the response affected by 100 μM IBMX[2].