Single-cell RNA sequencing reveals B cell dynamics and osteoclast activation in Talaromycosis-related bone destruction.

Objective: To explore the changes in bone destruction caused by Talaromycosis and its potential mechanisms.

Methods: We assessed bone destruction and its severity using Micro CT, hematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, F-actin staining, and Western blotting. We evaluated the biomechanical properties and pain perception in mice through biomechanical testing and the von Frey test. Single-cell RNA sequencing was used to analyze B cell composition in mouse tibial bone marrow, with findings verified by flow cytometry and qRT-PCR. Inflammatory cytokine levels, reactive oxygen species (ROS), and mitochondrial membrane potential were measured via enzyme-linked immunosorbent assay, immunofluorescence, and flow cytometry. Key proteins in the MAPK signaling pathway were also evaluated using Western blot.

Results: Talaromyces marneffei (TM) infection led to increased osteoclast activity and significant bone destruction, accompanied by a reduction in weight gain, increased pain, and diminished bone biomechanical properties in mice. Post-infection, an increase in the number of B cells, particularly Naïve-B, ProB, and mature B cells, was observed, potentially linked to oxidative phosphorylation processes. TM infection elevated inflammatory cytokines production, ROS production and decreased mitochondrial membrane potential in vivo and in vitro. Furthermore, TM infection enhanced osteoclast differentiation through the activation of MAPK signaling pathways, including p38, ERK, and JNK.

Conclusion: TM infection induces B cell maturation and promotes bone destruction in the tibia of mice. This effect may be associated with mitochondrial apoptosis and ROS production during oxidative phosphorylation, potentially through MAPK pathway activation.