Genetic Evidence for Inhibition of Bacterial Division Protein FtsZ by Berberine

Abstract

BackgroundBerberine is a plant alkaloid that is widely used as an anti-infective in traditional medicine. Escherichia coli exposed to berberine form filaments, suggesting an antibacterial mechanism that involves inhibition of cell division. Berberine is a DNA ligand and may induce filamentation through induction of the SOS response. Also, there is biochemical evidence for berberine inhibition of the cell division protein FtsZ. Here we aimed to assess possible berberine mechanism(s) of action in growing bacteria using genetics tools.Methodology/Principal FindingsFirst, we tested whether berberine inhibits bacterial growth through DNA damage and induction of the SOS response. The SOS response induced by berberine was much lower compared to that induced by mitomycin C in an SOS response reporter strain. Also, cell filamentation was observed in an SOS-negative E. coli strain. To test whether berberine inhibits FtsZ, we assessed its effects on formation of the cell division Z-rings, and observed a dramatic reduction in Z-rings in the presence of berberine. We next used two different strategies for RNA silencing of ftsZ and both resulted in sensitisation of bacteria to berberine, visible as a drop in the Minimum Inhibitory Concentration (MIC). Furthermore, Fractional Inhibitory Concentration Indices (FICIs) showed a high level of synergy between ftsZ silencing and berberine treatment (FICI values of 0.23 and 0.25 for peptide nucleic acid- and expressed antisense RNA-based silencing of ftsZ, respectively). Finally, over-expression of ftsZ led to a mild rescue effect in berberine-treated cells.ConclusionsThe results argue against DNA binding as the primary mechanism of action of berberine and support the hypothesis that its antibacterial properties are due to inhibition of the cell division protein FtsZ. In addition, the genetic approach used here provides a means to rapidly test the activity of other putative FtsZ inhibitors.

Plant-Derived Antimicrobials: Insights into Mitigation of Antimicrobial Resistance

“…It has been reported that isoquinoline such as chelerythrine possess two mechanisms in inhibiting the growth of bacterial cells; through inhibiting the cellular division and nucleic acid synthesis. Isoquinoline inhibits cellular division by tampering with the FtsZ protein, a protein which is essential for the Z ring formation during cellular division [98][99]. In addition, the synthesis of nucleic acids is also inhibited as isoquinoline inhibits the action of type I topoisomerases; this prevents the translation of antibiotic resistant genes, increasing bacterial susceptibility towards antibiotics [100].…”

Characterization of Osmotically Induced Filaments of Salmonella enterica

“…FtsZ is a well-studied member of this family of proteins; at nonpermissive temperatures, ftsZ mutants of Escherichia coli are incapable of cellular division (4,9,10,33,56). Likewise, hydrostatic pressure, the SOS response via SulA, and antimicrobials, such as berberine and cinnamaldehyde, induce filamentation of E. coli by preventing the polymerization of FtsZ (5,12,13,24,30,39,55). ␤-Lactam antibiotics that bind penicillin-binding protein 3 (PBP3, also known as FtsI) inhibit its enzymatic activity and septum formation but not cellular growth (46,62).…”

Antibacterial Activity of Polygonum pulchrum Blume Ethanol Extract on Staphylococcus aureus and Escherichia coli

“…12 The isoquinolines perturbate of the Z-ring and inhibition cell division. 13,14 The quinolones, which is lack of the 3-carboxyl group, unable to inhibit the type II topoisomerase enzymes (Heeb). 15 Agelasines inhibit BCG 3185c enzyme, a suspected dioxygenase which thereby allows disruption of bacterial homeostasis.…”