Association of ompU gene in Vibrio cholerae from patients and environment with bile resistance.

The objective of this study was to determine whether Vibrio cholerae, possessing ompU isolated from patients and the environment, conferred bile resistance and whether other virulence genes were also related to bile resistance. Fifty-two V cholerae O1 and non-O1 isolates were examined by PCR for the presence of the virulence-associated and regulatory genes, ctxA, tcpA, zot, ace, ompU, toxR, hlyA and stn/sto. V. cholerae possessing ompU resistant to equal or greater than 10% sodium deoxycholate were found in 93% of isolates but only in 9% of V. cholerae isolates not possessing ompU. The effects of other virulence genes on bile resistance could not be ascertained in this study. Thus V cholerae non-O1 with ompU and possibly other virulence genes isolated from the environment have the potential of affecting public health.

Modulation of Colon Cancer Cell Invasiveness Induced by Deoxycholic Acid / 대한소화기학회지

BACKGROUND/AIMS: Deoxycholic acid (DCA), a secondary bile acid, has been implicated to promote colon cancer growth and progression. However, its molecular mechanisms are largely unknown. In this study, we investigated the effects of DCA on proliferation, migration, and invasiveness of colon cancer cells (HT-29). METHODS: HT-29 cells were incubated with either medium (control) only or DCA for 24-48 hours. Time courses of RT-PCR for vascular endothelial growth factor (VEGF) and hypoxia-inducible factor (HIF)-1alpha mRNA expression, Western blotting for VEGF and matrix metalloproteinase (MMP)-9, zymography for MMP-9 activation, and wound-migration assay were determined after various concentrations of DCA (0-80mum) treatment. Moreover, these experiments were reassessed after pretreatments (2-6 hours) with specific inhibitors of various signal pathways. RESULTS: DCA enhanced HIF-1alpha mRNA expression, VEGF mRNA and VEGF protein expression, MMP-9 protein expression/activation, and cell migration ability in a dose-related manner. DCA-induced VEGF protein expression was inhibited by pretreatment with NS-398 (COX-2 inhibitor), PDTC (NF-kappaB inhibitor), or tauroursodeoxycholic acid (TUDC). DCA-induced cell migration ability was inhibited by pretreatment of GF109203X, a protein kinase C inhibitor. DCA-induced MMP-9 protein expression/activation was inhibited by pretreatment with SB203580, U0126, or PDTC. CONCLUSIONS: DCA significantly upregulates invasive and angiogenic potentials of human colon cancer cells through multiple signal transduction pathways.

Deoxycholic Acid-Induced Signal Transduction in HT-29 Cells: Role of NF-kappa B and Interleukin-8 / 대한소화기학회지

BACKGROUND/AIMS: Deoxycholic acid (DCA) has been appeared to be an endogenous colon tumor promoter. In this study, we investigated whether DCA induces nuclear factor-kappa B (NF-kappa B) activation and IL-8 expression, and tauroursodeoxycholic acid (TUDC) inhibits this signaling in HT-29 cells. METHODS: After DCA treatments, time courses of NF-kappa B binding activity were determined by electrophoretic mobility shift assay (EMSA). Also, we performed Western blotting of I kappa B alpha to confirm NF-kappa B activation. Time and concentration courses of DCA-induced secretion of IL-8 were measured with ELISA in supernatants of cultured media from the cells. To evaluate the role of NF-kappa B, IL-8 levels were assessed after pretreatment with using phosphorothioate-modified anti-sense oligonucleotides (ODN). Moreover, DCA-induced secretions of IL-8 were measured after pretreatment with TUDC. RESULTS: DCA dose-dependently induced prominent NF-kappa B binding complexes from 30 min to 8 hr and degradation of I kappa B alpha. The secretions of IL-8 were increased with DCA (50~200 micro M) treatment in a time and dose-dependent manner. Pre-incubation of the cells with TUDC (0.1~10 micro M) for 2 hours caused significant decreases in DCA induced IL-8 secretion. However, transient transfection using p50 or p65 AS-ODN showed no effect on IL-8 secretion. CONCLUSIONS: DCA may play as a colonic tumor promoter through anti-apoptotic effect of NF-kappa B activation and IL-8 expression, and DCA-induced NF-kappa B independent IL-8 expression is inhibited by TUDC.

Detergent dissection of membrane proteins of Entamoeba histolytica and its effect on lymphokine release in in vitro.

Fifty-two amoebic liver abscess cases were assessed for the release of lymphokines (LMIF) using detergent dissected membrane proteins (DDMP) of axenic Entamoeba histolytica (NIH:200) obtained with sodium deoxycholate treatment. Lymphokines release by T lymphocytes in response to both DDMP and whole amoebic lysate (WAL) was tested by leukocyte migration inhibition test on blood samples from amoebic liver abscess cases. A significant increase was noted in the release of LMIF and 100% positivity was observed with DDMP compared to whole amoebic extract with a positivity of 73%. The difference between means of the above two with regards to release of LMIF was found to be highly significant (P less than 0.005). This shows the patients had high degree of leukocyte sensitization to surface antigens of E. histolytica compared to the whole amoebic lysate. These findings suggest that the antigens shed might have important role as a potent antigen in elicitation of CMI response in amoebic liver abscess cases.

Immunogenicity of detergent membrane proteins of Entamoeba histolytica.

The lymphokine release and antibody production were assessed in the peripheral blood of 52 and 48 cases of amoebic liver abscess respectively, by employing detergent dissected membrane proteins (DDMP) of axenic Entamoeba histolytica (NIH:200). Lymphokine release by T lymphocytes in response to both DDMP and whole amoebic lysate (WAL) was performed by leukocyte migration inhibition test. A highly increased release of LMIF and 100 per cent positivity was observed with DDMP where as the same for whole amoebic extract, was only 73 per cent. The difference between the means of the above two values with regards to release of LMIF, was found to be highly significant (P less than 0.005). Antibodies production in response to both DDMP and whole amoebic lysate was performed by indirect haemagglutination assay on blood samples from amoebic liver abscess cases. A 53 folds increased titres of IHA and cent percent positivity was observed with DDMP compared to WAL. The difference between mean titres of the above two with regards to detection of antibodies, was found to be highly significant (P less than 0.001). This shows that the patients, had high degree of leukocyte sensitization and production of antibodies which will not be assessed simply with WAL. These findings suggest that the shed material might have important role as a potent antigen in elicitation cell mediated and humoral immune response in amoebic liver abscess cases.

Efecto de los ácidos biliares sobre la contractibilidad miometral en útero gestante aislado / Effect of bile acids on myometral contractility of isolated pregnant uterus

Usando un bioensayo tipo cascada nosotros estudiamos el efecto de los ácidos biliares sobre la contracción del útero aislado de ratas preñadas (día 19). Tanto el ácido cólico como deoxicólico a concentraciones entre 2 y 20 *M, causaron una estimulación significativa y dosis-dependiente de la contracción uterina (p<0,0001). El efecto máximo se alcanzó con una concentración de 15 *M. Ambos ácidos biliares fueron también estudiados en un medio libre de calcio y en presencia de calcio más indometacina. La oxitocina fue también administrada bajo las mismas condiciones. La ausencia de calcio en el medio de perfusión, inhibió la actividad uterina inducida por ambos ácidos biliares, en cambio la indometacina sólo logró reducir la contractibilidad levemente y en forma no significativa. El efecto de la oxitocina no fué modificado ni por la ausencia de calcio, ni por la presencia de indometacina. Nosotros concluímos que tanto el ácido cólico como el deoxicólico estimulan la actividad uterina in vitro y sugerimos que dichos agentes aumentan la entrada de calcio a la miocélula, ya sea alterando la arquitectura de la membrana plasmática o penetrando a la célula como complejos calcio-ácidos biliares