Adsorption of Phenazines Produced by Pseudomonas aeruginosa Using AST-120 Decreases Pyocyanin-Associated Cytotoxicity

Abstract

AST-120 (Kremezin) is used to treat progressive chronic kidney disease by adsorbing uremic toxin precursors produced by the gut microbiota, such as indole and phenols. Previously, we found that AST-120 decreased drug tolerance and virulence in Escherichia coli by adsorbing indole. Here, we show that AST-120 adsorbs phenazine compounds, such as pyocyanin, produced by Pseudomonas aeruginosa including multidrug-resistant P. aeruginosa strains, and suppresses pyocyanin-associated toxicity in A-549 (alveolar adenocarcinoma) and Caco-2 (colon adenocarcinoma) cells. Addition of fosfomycin, colistin and amikacin, which are often used to treat P. aeruginosa, inhibited the bacterial growth, regardless of the presence or absence of AST-120. These results suggest a further benefit of AST-120 that supports anti-Pseudomonas chemotherapy in addition to that of E. coli and propose a novel method to treat P. aeruginosa infection.

Oral Absorbent AST-120 Is Associated with Compositional and Functional Adaptations of Gut Microbiota and Modification of Serum Short and Medium-Chain Fatty Acids in Advanced CKD Patients

“…In addition to the uremic toxin-lowering effect, several other lines associated with intestinal microbiota modifications have been reported with administration of AST-120. This compound had anti-cytotoxic effects against Escherichia coli and Pseudomona aeruginosa by changing gut microbial enzymatic metabolism leading to decreased drug tolerance and virulence [ 31 , 32 ]. AST-120 treatment was associated with a reduced ratio of Bacteroidetes to Firmicutes (B/F ratio) in the feces of the db/db mice.…”

Adsorption of extracellular proteases and pyocyanin produced by Pseudomonas aeruginosa using a macroporous magnesium oxide-templated carbon decreases cytotoxicity

“…Cytotoxicity of bacterial cultures to human intestinal epithelial cells was estimated in a cell viability assay as previously described ( Hirakawa et al., 2021b ). Bacteria were grown in LB medium for 24 h. A total of the 50 μL of bacteria-free culture supernatants was diluted into 50 μL DMEM containing 10% HyClone FetalClone III serum, and added to cultured Caco-2 cells in a 96-well plate.…”

“…The pyocyanin level was determined as previously described ( Essar et al., 1990 ; Hirakawa et al., 2021b ). Bacteria were grown in LB medium for 24 h and the cell cultures were centrifuged to remove the cell pellets.…”

“…The promoter activities of lasI and rhlA were measured as previously described ( Hirakawa et al., 2021b ). The PAO1 strains carrying each reporter plasmid, pBBRlasI (PAO1)-P or pBBRrhlA (PAO1)-P, were grown in the presence and absence of 30 mg MgOC 150 in 5 mL of LB medium to the early stationary phase (OD 600 =2.0).…”

“…Pyocyanin is the most-characterized non-protein molecule that contributes to virulence of P. aeruginosa , and it impairs host cells by generating reactive oxygen species ( Hall et al., 2016 ). We previously found that AST-120, adsorbs pyocyanin produced by P. aeruginosa, and attenuated pyocyanin-associated toxicity to intestinal epithelial cells ( Hirakawa et al., 2021b ). This finding leads to the focus of potency of porous carbon as an anti-Pseudomonas option.…”