Antisense inhibition of accA in E. coli suppressed luxS expression and increased antibiotic susceptibility

Bacterial multiple drug resistance is a significant issue for the medical community. Gram-negative bacteria exhibit higher rates of multi-drug resistance, partly due to the impermeability of the Gram-negative bacterial cell wall and double-membrane cell envelope, which limits the internal accumulation of antibiotic agents. The outer lipopolysaccharide membrane regulates the transport of hydrophobic molecules, while the inner phospholipid membrane controls influx of hydrophilic particles. In Escherichia coli, the gene accA produces the acetyl-CoA carboxylase transferase enzyme required for catalyzing synthesis of fatty acids and phospholipids that compose the inner membrane. To increase antibiotic susceptibility and decrease growth, this study interrupted fatty acid synthesis and disrupted the composition of the inner membrane through inhibiting the gene accA with antisense RNA. This inhibition suppressed expression of luxS, a vital virulence factor that regulates cell growth, transfers intercellular quorum-sensing signals mediated by autoinducer-2, and is necessary for biofilm formation. Bacterial cells in which accA was inhibited also displayed a greater magnitude of antibiotic susceptibility. These findings confirm accA as a potent target for developing novel antibiotics such as antimicrobial gene therapies.