Repurposing anti-diabetic drug “Sitagliptin” as a novel virulence attenuating agent in Serratia marcescens

Abstract

Background Serratia marcescens is an emerging pathogen that causes a variety of health care associated infections. S. marcescens is equipped with an arsenal of virulence factors such as biofilm formation, swimming and swarming motilities, prodigiosin, protease and others which enable it to initiate and cause the infection. These virulence factors are orchestrated under the umbrella of an intercellular communication system named Quorum sensing (QS). QS allows bacterial population to synchronize the expression of virulence genes upon detection of a chemical signaling molecule. Targeting bacterial virulence is a promising approach to attenuate bacteria and enhances the ability of immune system to eradicate the bacterial infection. Drug repurposing is an advantageous strategy that confers new applications for drugs outside the scope of their original medical use. This promising strategy offers the use of safe approved compounds, which potentially lowers the costs and shortens the time than that needed for development of new drugs. Sitagliptin is dipeptidyl peptidase-4 (DPP-4) inhibitor, is used to treat diabetes mellitus type II as it increases the production of insulin and decreasing the production of glucagon by the pancreas. We aimed in this study to repurpose sitagliptin, investigating the anti-virulence activities of sitagliptin on S. marcescens. Methods The effect of sub-inhibitory concentrations of sitagliptin on virulence factors; protease, prodigiosin, biofilm formation, swimming and swarming motilities was estimated phenotypically. The qRT-PCR was used to show the effect of sitagliptin on the expression of QS-regulated virulence genes. The in-vivo protective activity of sitagliptin on S. marcescens pathogenesis was evaluated on mice. Results Sitagliptin (1 mg/ml) significantly reduced the biofilm formation, swimming and swarming motilities, prodigiosin and protease. The qRT-PCR confirmed the effect on virulence as shown by down regulating the expression of fimA, fimC, flhC, flhD, bsmB, rssB, rsmA, pigP,

Repurposing Anti-diabetic Drugs to Cripple Quorum Sensing in Pseudomonas aeruginosa

“…The ability of tested anti-diabetic drugs to inhibit biofilm formation was analyzed using the microtitre dish biofilm formation assay [ 6 , 26 ]. Aliquots of 10 μL of the P. aeruginosa suspension were adjusted approximately to OD600 of 0.4 and added to 1 mL amounts of fresh TSB with and without 1/10 MIC of the tested drugs.…”

“…The abilities of anti-diabetic drugs to interfere in the P. aeruginosa swimming, swarming and twitching motilities were investigated [ 6 , 27 , 28 ]. For swimming or swarming assay, 0.3% or 0.5% LB agar plates with or without the tested drugs in sub-MIC were point inoculated with 5 µL of the bacterial suspension and the plates were incubated at 37 °C for 24 h. For the twitching assay, 1% LB agar plates with or without the tested drugs in sub-MIC were centrally stabbed with 5 μL of the P. aeruginosa suspensions and incubated for 48 h at 37 °C.…”

“…Dozens of studies describe how the clinically-relevant bacteria utilize QS to control the collective production of virulence factors and the efforts to inhibit QS in these pathogens with the aim of designing new efficient antimicrobial therapeutics [ 3 , 4 , 5 ]. In this direction, we and several groups studied the ability of several compounds and chemical moieties to serve as anti-biofilm and anti-QS agents, giving a great consideration to these chemical compounds as their safeties have been already approved [ 6 , 7 ].…”

“…Furthermore, metformin potentiated the antibacterial activities of gold nanoparticles and augmented the biofilm eradication [ 12 ]. Significantly, we showed in a previous work that a pyrazine derivative with triazole moiety anti-diabetic drug sitagliptin can be repurposed as a virulence mitigating agent in Serratia marcescens [ 6 ]. Vildagliptin is another oral anti-diabetic containing pyrrolidine chemical moiety that was proven to have antifungal and antibacterial activity against P. aeruginosa , showing anti-QS activity [ 13 ].…”

“…P. aeruginosa causes severe infections in diabetic “immunocompromised” patients and constitutes a real obstacle to be resolved, especially in wound infections and diabetic foot infections [ 22 , 23 ]. Bearing in mind the approved anti-virulence efficiency of anti-diabetic sitagliptin against Serratia marcescens [ 6 ], we aimed to investigate more anti-diabetic drugs against P. aeruginosa . In the current study we aimed to investigate the possibility of repurposing the chemically diverse anti-diabetic drugs sitagliptin, vildagliptin and metformin as inhibitors of P. aeruginosa QS in-vitro and in-vivo.…”