Abstract

TREATMENT OF MICE WITH TLR4 AND IFN-? ANTIBODY AND EXOGENOUS IL-10 MODULATES BCL2 AND LC3 EXPRESSION IN RANKL/M-CSF PLUS LPS STIMULATED BONE MARROW MACROPHAGES- LEADING TO BONE RESORPTION

Gopinath Mukherjee, Sharmistha Samanta, Sreya Chattopadhyay, Sandip Mukherjee, Tiyesh Paul, Biswadev Bishayi*

ABSTRACT

Bone marrow derived macrophages activation must be precisely regulated to ensure an effective immune response to infectious agents while preventing excessive inflammation and associated toxicity. Toll-like receptor 4 (TLR4) is activated by lipopolysaccharide (LPS) from Gram-negative bacteria, initiating pro-inflammatory signaling cascadesleading to bone damage.Moreover,LPS-induced cellular autophagy plays a critical role in osteoclastogenesis and bone resorption, primarily through the LC3-mediated pathway. Whereas, elevated levels of the anti-apoptotic protein BCL2 can counteract this effect and restore bone integrity.Our study demonstrates that treatment with TLR4 antibody (TLR4Ab) and IFN-γ antibody (IFNγAb), combined with exogenous IL-10in LPS induced bone damage model, effectively downregulates cellular reactive oxygen species (ROS), leading to suppressed mTOR expression and subsequent regulation of pro-inflammatory cytokine production in LPS stimulated bone marrowmacrophages. Moreover, dual antibody treatment prior to LPS induced bone damage and post-IL-10 administration restores the phagocytic capacity of undifferentiated RBMCs as evidenced by improved membrane fluidity and bacterial engulfment. These findings highlight the therapeutic potential of targeting TLR4 and IFNγ, along with IL-10 supplementation, to mitigate LPS-induced bone inflammation by suppressing autophagy-driven osteoclastogenesis. This approach offers a promising strategy for preventing bacterial infection-associated bone loss and warrants further investigation as a potential therapeutic intervention in inflammatory bone diseases.

Keywords: Bone resorption; Lipopolysaccharide; TLR4, IFN?, Autophagy.