Exploring Placental Protein-Target Protein Interactions: In Silico and In Vitro Approaches for Osteoarthritis Therapy.

Background: Osteoarthritis (OA) is a persistent joint condition marked by gradual softening and breakdown of articular cartilage. Current research in OA treatment explores biologics that target proinflammatory cytokines and proteases, as well as promote chondrocyte regeneration and cartilage repair. Human placental tissues, abundant in anti-catabolic factors, can mitigate cartilage degradation by inhibiting protease expression and maintaining cartilage homeostasis in the presence of anabolic factors.

Objective: This investigation examined placental protein interactions with proteases and OA target proteins through protein-protein docking and dynamic studies.

Method: The NCBI conserved domain database was utilized to predict functional protein domains. Protein sequence motifs were identified using literature, the MEME suite tool, and the My- Hits database. The Expasy-ProtParam online tool was employed to analyze protein physical parameters. ClusPro Advanced Options was used to dock binding site residues of selected placental proteins against specific OA target proteins, while PDBsum and Biovia Discovery Studio were used to visualize and examine molecular interactions. A 100 ns molecular dynamics (MD) study was conducted using DESMOND software.

Result: Protein-protein docking revealed strong interactions of placental proteins with docking scores ranging from -1700 to -2450.3 against proteases and -900 to -1400 against specific target proteins. PDBsum analysis of placental protein-target protein docked complexes revealed residue interactions, hydrogen bonds, and non-bonded contacts. Molecular dynamics simulations further confirmed the stability of these complexes, indicating favorable protein-protein interactions (PPIs). The anti-inflammatory activity of human placental tissue against lipopolysaccharide-induced macrophages was investigated using flow cytometry.

Conclusion: These results provide a foundation for future experimental studies to confirm the predicted interactions and to explore their potential therapeutic applications in OA treatment. Additionally, patients with OA and other arthritic conditions could benefit from the biologics chondroprotective biofactors, which serve as a promising alternative to conventional knee replacement surgery.