Identification of Mycoplasma pneumoniae P1-interacting proteins by GST pull-down and analysis of its transcriptomic regulation in A549 cells.

Mycoplasma pneumoniae (M. pneumoniae) is a major pathogen causing community-acquired pneumonia in children. Its pathogenic process relies on the adherence to and colonization of host respiratory epithelial cells. P1 protein is the primary adhesin of M. pneumoniae, directly mediating its binding to host cells. To explore the interaction mechanism between P1 recombinant protein and host cells, we conducted protein expression and purification, glutathione S-transferase (GST) pull-down assay, and transcriptome sequencing. The rP1-GST fusion protein was expressed under confirmed induction conditions (16°C, 0.1 mM IPTG). GST pull-down assay identified 22 differentially expressed membrane proteins in the rP1-GST group, among which annexin A2 (ANXA2) and C-C chemokine receptor type 5 (CCR5) were significantly altered and interact with P1 adhesin. Both ANXA2 and CCR5 possessed multiple functions including protein binding, receptor activity and signal sensor activity. Transcriptome analysis indicated that differentially expressed genes from rP1-A549 cell interaction were significantly enriched in multiple Gene Ontology (GO) terms and KEGG pathways. These results suggest that ANXA2 and CCR5 may serve as potential binding partners of P1 adhesin. P1 adhesin may regulate host genes involved in mitochondria and energy metabolism. These findings provide clues for understanding the adhesion and pathogenesis of M. pneumoniae.