Thursday, November 21, 2024
11/21/2024
Project Summary Rates of the disease human vibriosis caused by Vibrio infections are steadily rising world-wide, correlating with rising ocean temperatures and increased Vibrio abundance and broader distribution in marine ecosystems, coastal waters, and aquaculture farms. Multi-drug resistant Vibrio isolates are becoming more prevalent, limiting the efficacy of traditional antibiotic therapy in this rapidly progressing acute disease. Thus, there is an urgent need to develop alternative and combinatorial therapeutics for treatment of Vibrio infections. In Vibrio species, the major pathway that controls pathogenesis is quorum sensing: cell-cell chemical communication that bacteria use to control gene expression in response to changes in the number of bacteria around them. In all pathogenic Vibrios, the central quorum sensing regulator LuxR/SmcR is necessary for virulence in hosts and controls genes critical for pathogenesis: proteases, hemolysins, cytotoxins, siderophores, and biofilms. Thus, LuxR/SmcR proteins are promising targets for drug development to directly inhibit quorum sensing and prevent Vibrio pathogenesis. Thiophenesulfonamide compounds such as PTSP (3- phenyl-1-(thiophen-2-ylsulfonyl)-1H-pyrazole) are potent, stable, fast-acting, specific inhibitors of LuxR/SmcR proteins, but do not affect Vibrio cell growth or viability even at high concentrations. PTSP compounds block protease and hemolysin production and protect shrimp from Vibrio infection in vivo. Thus, the long-term goal of this research program is to develop PTSP and its derivatives into anti-quorum sensing therapeutic compounds that treat vibriosis disease in humans. The primary causative agent of acute illness, morbidity, and mortality from human vibriosis disease is Vibrio vulnificus. The proposed research aims to assess the efficacy of these compounds at preventing colonization, decreasing virulence, and treating established V. vulnificus infections. To accomplish these goals, the research team will employ a novel ex vivo human skin infection model for wound infections. Pilot experiments demonstrated rapid V. vulnificus colonization and degradation of the dermal-epidermal tissues, which are similar to phenotypes observed in the clinic. The proposed research will apply the three-dimensional (3D) imaging technique called MiPACT to the ex vivo skin model to visualize V. vulnificus cells in situ. The powerful combination of the ex vivo skin infection model and 3D-imaging method will enable the research team to accomplish two primary aims: 1) examine the role of core virulence factors during early infection and 2) assess the efficacy of PTSP treatment on V. vulnificus colonization. Collectively, the proposed research will enable ex vivo studies of human skin reactions to V. vulnificus colonization and provide a broad platform for observation of virulence factor effects via 3D-microscopy, in order to evaluate thiophenesulfonamide compound efficacy against V. vulnificus skin infections.
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