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Validation of the tetracycline regulatable gene expression system for the study of the pathogenesis of infectious disease.

Chaturvedi AK, Lazzell AL, Saville SP, Wormley FL, Monteagudo C, Lopez-Ribot JL - PLoS ONE (2011)

Bottom Line: However, some immunomodulatory effects of the tetracyclines, including doxycycline, could potentially limit its use to evaluate host responses during infection.We demonstrate that the pathogenesis of the wild type C. albicans CAF2-1 strain, which does not contain any tet-regulatable element, is not affected by the presence of doxycycline.Our results indicate that the levels of doxycycline needed to control the tetracycline regulatable promoter gene expression system have no detectable effect on global host responses during candidiasis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, Texas, United States of America.

ABSTRACT
Understanding the pathogenesis of infectious disease requires the examination and successful integration of parameters related to both microbial virulence and host responses. As a practical and powerful method to control microbial gene expression, including in vivo, the tetracycline-regulatable system has recently gained the favor of many investigative groups. However, some immunomodulatory effects of the tetracyclines, including doxycycline, could potentially limit its use to evaluate host responses during infection. Here we have used a well-established murine model of disseminated candidiasis, which is highly dependent on both the virulence displayed by the fungal cells and on the host immune status, to validate the use of this system. We demonstrate that the pathogenesis of the wild type C. albicans CAF2-1 strain, which does not contain any tet-regulatable element, is not affected by the presence of doxycycline. Moreover levels of key cytokines, chemokines and many other biomarkers, as determined by multi-analyte profiling, remain essentially unaltered by the presence of the antibiotic during infection. Our results indicate that the levels of doxycycline needed to control the tetracycline regulatable promoter gene expression system have no detectable effect on global host responses during candidiasis. Because tet-regulatable systems are now being increasingly used in a variety of pathogenic microorganisms, these observations have wide implications in the field of infectious diseases.

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Doxycycline does not affect an expanded number of host analytes and biomarkers during systemic candidiasis Multiplex analysis using the mouse multi-analyte profiling (MAP, Rules-Based Medicine) of pooled kidney tissue homogenates obtained from a group of doxycycline-treated mice (n = 5) three days post-infection with C. albicans CAF2-1 strain as compared to doxycycline-untreated (control) animals.Comparative values are expressed as Ratio vs Control (infected in the absence of doxycycline, sacrificed at the very same time), which is arbitrarily assigned a value of 1 for each analyte and indicated by the solid grid line along the y axis. The dotted grid lines along the y axis indicate ratios of 0.5 and 2, set up arbitrarily; any analyte for which the corresponding value was below or above this range was considered to be affected by the antibiotic.
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pone-0020449-g003: Doxycycline does not affect an expanded number of host analytes and biomarkers during systemic candidiasis Multiplex analysis using the mouse multi-analyte profiling (MAP, Rules-Based Medicine) of pooled kidney tissue homogenates obtained from a group of doxycycline-treated mice (n = 5) three days post-infection with C. albicans CAF2-1 strain as compared to doxycycline-untreated (control) animals.Comparative values are expressed as Ratio vs Control (infected in the absence of doxycycline, sacrificed at the very same time), which is arbitrarily assigned a value of 1 for each analyte and indicated by the solid grid line along the y axis. The dotted grid lines along the y axis indicate ratios of 0.5 and 2, set up arbitrarily; any analyte for which the corresponding value was below or above this range was considered to be affected by the antibiotic.

Mentions: A more comprehensive analysis of the global host response in the different groups of mice was performed by multianalyte profiling using the Rules Based Medicine's mouse MAP, that allows for the concomitant examination of an extended panel of broad spectrum biomarkers relevant to infection (a total of 59 analytes, including cytokines, chemokines, growth factors, acute-phase reactants and other metabolites). Figure 3 shows the results of multianalyte profiling analyses for kidney samples (the kidney is the main target of infection) obtained from doxycycline-treated mice 3 days after infection with C. albicans CAF2-1 strain, compared to animals infected in the absence of the antibiotic. This direct comparison revealed no major differences in levels of the multiple analytes between doxycycline-treated versus untreated mice, thus corroborating that the antibiotic has a minimal (if any) effect on host responses under the conditions used. Similar results were obtained in a comparison between the doxycycline-treated and untreated uninfected animals, further demonstrating that basal levels of these biomarkers in the absence of infection are unaffected by doxycycline treatment (see Figure S2). The absolute values for the different analytes in each group of mice are provided in Table S1. Results from similar analyses for spleen homogenates and serum samples also indicated a global lack of effect of antibiotic treatment on systemic host responses, both with and without infection (data not shown).


Validation of the tetracycline regulatable gene expression system for the study of the pathogenesis of infectious disease.

Chaturvedi AK, Lazzell AL, Saville SP, Wormley FL, Monteagudo C, Lopez-Ribot JL - PLoS ONE (2011)

Doxycycline does not affect an expanded number of host analytes and biomarkers during systemic candidiasis Multiplex analysis using the mouse multi-analyte profiling (MAP, Rules-Based Medicine) of pooled kidney tissue homogenates obtained from a group of doxycycline-treated mice (n = 5) three days post-infection with C. albicans CAF2-1 strain as compared to doxycycline-untreated (control) animals.Comparative values are expressed as Ratio vs Control (infected in the absence of doxycycline, sacrificed at the very same time), which is arbitrarily assigned a value of 1 for each analyte and indicated by the solid grid line along the y axis. The dotted grid lines along the y axis indicate ratios of 0.5 and 2, set up arbitrarily; any analyte for which the corresponding value was below or above this range was considered to be affected by the antibiotic.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3102114&req=5

pone-0020449-g003: Doxycycline does not affect an expanded number of host analytes and biomarkers during systemic candidiasis Multiplex analysis using the mouse multi-analyte profiling (MAP, Rules-Based Medicine) of pooled kidney tissue homogenates obtained from a group of doxycycline-treated mice (n = 5) three days post-infection with C. albicans CAF2-1 strain as compared to doxycycline-untreated (control) animals.Comparative values are expressed as Ratio vs Control (infected in the absence of doxycycline, sacrificed at the very same time), which is arbitrarily assigned a value of 1 for each analyte and indicated by the solid grid line along the y axis. The dotted grid lines along the y axis indicate ratios of 0.5 and 2, set up arbitrarily; any analyte for which the corresponding value was below or above this range was considered to be affected by the antibiotic.
Mentions: A more comprehensive analysis of the global host response in the different groups of mice was performed by multianalyte profiling using the Rules Based Medicine's mouse MAP, that allows for the concomitant examination of an extended panel of broad spectrum biomarkers relevant to infection (a total of 59 analytes, including cytokines, chemokines, growth factors, acute-phase reactants and other metabolites). Figure 3 shows the results of multianalyte profiling analyses for kidney samples (the kidney is the main target of infection) obtained from doxycycline-treated mice 3 days after infection with C. albicans CAF2-1 strain, compared to animals infected in the absence of the antibiotic. This direct comparison revealed no major differences in levels of the multiple analytes between doxycycline-treated versus untreated mice, thus corroborating that the antibiotic has a minimal (if any) effect on host responses under the conditions used. Similar results were obtained in a comparison between the doxycycline-treated and untreated uninfected animals, further demonstrating that basal levels of these biomarkers in the absence of infection are unaffected by doxycycline treatment (see Figure S2). The absolute values for the different analytes in each group of mice are provided in Table S1. Results from similar analyses for spleen homogenates and serum samples also indicated a global lack of effect of antibiotic treatment on systemic host responses, both with and without infection (data not shown).

Bottom Line: However, some immunomodulatory effects of the tetracyclines, including doxycycline, could potentially limit its use to evaluate host responses during infection.We demonstrate that the pathogenesis of the wild type C. albicans CAF2-1 strain, which does not contain any tet-regulatable element, is not affected by the presence of doxycycline.Our results indicate that the levels of doxycycline needed to control the tetracycline regulatable promoter gene expression system have no detectable effect on global host responses during candidiasis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, Texas, United States of America.

ABSTRACT
Understanding the pathogenesis of infectious disease requires the examination and successful integration of parameters related to both microbial virulence and host responses. As a practical and powerful method to control microbial gene expression, including in vivo, the tetracycline-regulatable system has recently gained the favor of many investigative groups. However, some immunomodulatory effects of the tetracyclines, including doxycycline, could potentially limit its use to evaluate host responses during infection. Here we have used a well-established murine model of disseminated candidiasis, which is highly dependent on both the virulence displayed by the fungal cells and on the host immune status, to validate the use of this system. We demonstrate that the pathogenesis of the wild type C. albicans CAF2-1 strain, which does not contain any tet-regulatable element, is not affected by the presence of doxycycline. Moreover levels of key cytokines, chemokines and many other biomarkers, as determined by multi-analyte profiling, remain essentially unaltered by the presence of the antibiotic during infection. Our results indicate that the levels of doxycycline needed to control the tetracycline regulatable promoter gene expression system have no detectable effect on global host responses during candidiasis. Because tet-regulatable systems are now being increasingly used in a variety of pathogenic microorganisms, these observations have wide implications in the field of infectious diseases.

Show MeSH
Related in: MedlinePlus