2013

2013. Drug Administration. This study examined whether CLA could be used as a new therapy to reduce CT production, which, in turn, would decrease disease duration and intensity in cholera patients. CLA could be used in place of traditional antibiotics and would be very unlikely to generate resistance, as it affects only virulence factor production and not bacterial growth or survival. INTRODUCTION Cholera is Cav 2.2 blocker 1 a devastating diarrheal disease that affects between 1.4 and 4.3 million people each year and causes Cav 2.2 blocker 1 an estimated 28,000 to 142,000 deaths annually (1, 2). The disease is characterized by voluminous, watery diarrhea that induces severe dehydration and can lead to hypovolemic shock and eventual death if not treated rapidly. Cholera is caused by oral ingestion of the Gram-negative bacterium serogroups have been identified, only the O1 and O139 serogroups have been implicated in epidemic and pandemic cholera. Cholera patients are clinically treated to prevent dehydration by the administration of oral rehydration solution (ORS), containing various salts and glucose (4). In severe cholera cases, intravenous rehydration is also used. Without treatment, the cholera survival rate can be as low as 50%, but rehydration with ORS raises the survival rate to more than 99% (5). Antibiotics are a secondary treatment option; however their use is typically limited to severe cases and used to shorten the duration of severe disease symptoms. To initiate disease, the production of two virulence factors is necessary: cholera toxin (CT) and toxin-coregulated pilus (TCP). CT is an A-B5 family toxin and is directly responsible for inducing the profuse watery cholera diarrhea (6), while TCP is necessary for host intestinal colonization (7). The expression of the genes encoding both of these virulence factors is under the control of the major virulence transcription activator, ToxT (8). ToxT is a member of the AraC/XylS family of transcription factors and Rabbit Polyclonal to eNOS (phospho-Ser615) consists of two domains, a C-terminal DNA binding domain that contains the AraC/XylS homology and an N-terminal domain that has been implicated in effector binding and, possibly, association of ToxT monomers (9). ToxT activity is modulated by both positive and negative effectors. The positive ToxT effector, bicarbonate, acts to enhance ToxT binding to its cognate DNA sites, known as toxboxes (10, 11). The negative ToxT effectors, unsaturated fatty acids present in bile, act to diminish ToxT binding to its cognate DNA sites (12, 13). Thus, these two effectors have opposing roles in transcription by simply altering ToxT binding affinity, likely by inducing structural alterations in the N-terminal domain (9, 11, 14). encounters high concentrations of bile in the small intestine before entering the mucosal layer, where it colonizes the epithelial surface (15,C17). However, unsaturated fatty acids are a relatively small component of the complex mixture that constitutes bile. In the presence of unsaturated fatty acids expresses its motility genes but does not express its major virulence genes encoding CT and TCP, as ToxT activity is strongly inhibited (18, 19). Because of the strong Cav 2.2 blocker 1 inhibiting effect of linoleic acid that was observed (13), we investigated whether linoleic acid could potentially act as a cholera therapeutic, reducing the production of CT and subsequently reducing the volume of diarrhea induced by CT in cholera. A conjugated form of linoleic acid, CLA, is sold over the counter in the United States as a weight loss supplement aimed at inhibiting fat absorption. As CLA is relatively inexpensive and easily accessible, we explored whether CLA could potentially be used as a supplemental cholera therapy to reduce disease duration and intensity in conjunction with oral rehydration. As antibiotic resistance becomes a more and more pressing problem, therapies that can inhibit pathogenesis, but not bacterial survival, are becoming much more attractive. Here, we show that CLA inhibits virulence gene expression by acting on ToxT. We also show that CLA strongly inhibits CT production and fluid accumulation in a rabbit ileal loop model. These findings suggest that CLA.