RNA binding protein PUM2 promotes IL-1β-induced apoptosis of chondrocytes via regulating FOXO3 expression

Area of Science:

• Molecular Biology
• Cell Biology
• Pathogenesis Research

Background:

• RNA-binding proteins (RBPs) play roles in disease pathogenesis.
• The specific role of RBPs in osteoarthritis (OA) pathogenesis remains underexplored.
• Understanding RBP functions in chondrocytes is crucial for OA research.

Purpose of the Study:

• To investigate the function and mechanism of the RBP PUM2 in chondrocyte apoptosis during osteoarthritis.
• To elucidate the regulatory role of PUM2 in the context of OA.

Main Methods:

• Quantitative real-time PCR (qRT-PCR) for PUM2 expression analysis in human OA cartilage and chondrocytes.
• MTT assay and flow cytometry to assess chondrocyte viability and apoptosis.
• Flow cytometry to measure reactive oxygen species (ROS) generation.
• RNA immunoprecipitation, RNA pull-down, and Luciferase reporter assays to determine PUM2 regulation of FOXO3 translation.

Main Results:

• PUM2 expression is upregulated in human OA cartilage and IL-1β-stimulated chondrocytes.
• PUM2 overexpression decreases chondrocyte viability and increases apoptosis and ROS generation.
• PUM2 silencing enhances chondrocyte viability and reduces IL-1β-induced apoptosis and ROS generation.
• PUM2 directly inhibits FOXO3 translation by binding to its 3'-untranslated region (3'-UTR).

Conclusions:

• PUM2 is upregulated in osteoarthritis cartilage.
• PUM2 positively regulates chondrocyte apoptosis.
• PUM2 exerts its function by controlling FOXO3 protein expression, forming a critical signaling axis in OA pathogenesis.