PSEUDOMONAS AERUGINOSA ADHERES TO APOPTOTIC CELLS THROUGH A FUNCTIONAL TYPE IV PILI FORMING STABLE CLUSTERS

CELESTE DEA; MARIA VICTORIA PEPE; ROSET, MARA SABRINA; FERNANDO PERUANI; ARLINET KIERBEL

Congreso; LVIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; 2022

The opportunistic pathogen Pseudomonas aeruginosa causes a wide range of acute and chronic infections. In cystic fibrosis (CF)airways, it forms multicellular aggregates called biofilms that are thought to contribute to chronic infection. Understanding theearly steps of the transition from a free-swimming to a multicellular and sessile state is critical for developing strategies againstchronic infections. We have reported that free-swimming P. aeruginosa attaches to apoptotic cells extruded from the epithelium,forming stable bacterial clusters. We further established that although clusters are permanent, individual adhesion is reversible andmediated by type IV pili (T4P). T4P are retractable filaments located at the poles of the bacterial cell and responsible for criticalfunctions such as twitching motility (a form of surface-associated bacterial movement), adhesion to biotic and abiotic surfaces,virulence, and biofilm formation. The semi-flexible polymers of T4P are formed majorly by pilin (PilA) subunits. Pilus extensionand retraction are mediated by PilB and PilT ATPases, respectively. There is another ATPase called PilU, which also contributesto pilus retraction, although its role is less clear. pilT mutants are typically hyperpiliated but totally impaired for twitching motility.