LQ23 is a selective inhibitor of CDC2-like kinase 2 (CLK2) with an IC50 of 1.4 nM, exhibiting anti-inflammatory activity [1].

LQ23, when used at concentrations of 10-100 nM, inhibits the phosphorylation of SR proteins in chondrocytes in a dose-dependent manner, consequently modulating gene alternative splicing [1]. It also dose-dependently suppresses CHIR99021-induced Wnt signaling in HEK-293T cells with an IC50 of 2.9 μM [1]. At a concentration of 30 nM, LQ23 enhances the differentiation of bone marrow mesenchymal stem cells (BMSC) into chondrocytes and prevents cartilage degeneration, which helps improve osteoarthritis [1]. According to a Western blot analysis [1], treatment of chondrocytes with 10-100 nM LQ23 for 1 hour resulted in decreased levels of phosphorylated SRSF4, SRSF5, and SRSF6, as well as reduced β-catenin and c-myc levels.

LQ23, administered as a single intra-articular injection at a dosage of 1.5 μg/kg, demonstrated anti-inflammatory properties, cartilage protection, and improved joint function in Sprague-Dawley rat models of osteoarthritis induced by monosodium iodoacetate (MIA) or ACLT-pMMx. Specific improvements observed include enhanced cartilage surface and cellular alignment, reduced synovial membrane thickness, increased space between the femur and tibia, and lowered levels of inflammatory cytokines and degradative enzymes. [1]