Mechanism of Scutellaria baicalensis extracellular vesicles in attenuating Mycoplasma gallisepticum-induced inflammation via TRPC1 - STIM1/ORAI1 channel inhibition

MAJOR OBJECTIVES: The infection caused by Mycoplasma gallisepticum (MG) has had a significant impact on the poultry industry. Scutellaria baicalensis extract has shown great potential in anti-MG infection, but the role and mechanism of its extracellular vesicles (EVs) remain unexplored. The aim of this study is to investigate the potential mechanism of Scutellaria baicalensis derived extracellular vesicles (SEVs) against MG, especially by regulating TRPC1-STIM1/ORAI1 signaling pathway, which is a key component of store-operated calcium entry (SOCE). METHODS: SEVs were obtained from Scutellaria baicalensis and subsequently subjected to characterization. Through in vitro and in vivo MG infection models, experimental techniques including non-targeted metabolomics, qRT-PCR, Western Blot and Fluo-4 AM calcium imaging were employed. Additionally, synergistic and antagonistic effects were demonstrated via siRNA-mediated STIM1 knockdown and plasmid overexpression experiments to validate its pivotal role. RESULTS: Non-targeted metabolomics analysis showed that SEVs treatment regulated metabolic pathways related to calcium signaling pathway compared with MG-infected group, which aided our study to determine that SEVs may affect inflammatory injury by affecting calcium signaling. The results of molecular experiments showed that SEVs markedly downregulated SOCE molecules (TRPC1, STIM1 and ORAI1) at mRNA and protein levels, effectively suppressing MG-induced abnormal intracellular calcium influx and reducing pro-inflammatory cytokine production. CONCLUSIONS: SEVs alleviate MG-induced inflammation through the TRPC1-STIM1/ORAI1 pathway, restoring calcium homeostasis and inhibiting NF-κB signaling and cytokine release. PRACTICAL APPLICATIONS: This study reveals a novel mechanism by which plant-derived exosome-like nanoparticles (PELNs) exert anti-inflammatory effects, highlighting their potential as a natural nanotherapeutic strategy for controlling MG infection in poultry.