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Jindal G, Tewari R, Gautam A, Pandey SK, Rishi P. Immunological characterization of recombinant Salmonella enterica serovar Typhi FliC protein expressed in Escherichia coli. AMB Express 2012; 2:55. [PMID: 23067582 PMCID: PMC3502275 DOI: 10.1186/2191-0855-2-55] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 09/29/2012] [Indexed: 11/17/2022] Open
Abstract
Like any other enteric pathogen, Salmonella also encounters acidic stress in the stomach as well as within the host macrophage milieu. However, the pathogen is reported to combat this stress through acid tolerance response (ATR), expressing a number of genes and eventually the proteins. Recently, an acid induced outer membrane phenotype encoded by fliC gene in Salmonella enterica serovar Typhi has been identified. In the present study, fliC gene was cloned to study its biological implications. The recombinant FliC (rFliC) protein was observed to stimulate the production of antibodies. These antibodies could also recognize the FliC protein (antigen) in the clinical samples i.e. blood samples from typhoid patents as well as healthy blood samples spiked with serovar Typhi. Moreover, the rFliC also reacted with the sera from patients suffering with typhoid fever indicating its in-vivo immunogenicity. Ex-vivo study revealed that rFliC has the potential to stimulate the macrophages to generate higher levels of inflammatory mediators such as malondialdehyde (MDA) and nitrite. The inflammatory potential of FliC was also confirmed in-vivo, by the paw oedema test as well as by flicking response of the inflamed paw indicating hyperalgesia occurring during inflammatory response. The findings of the present study indicate that acid induced FliC might be one of the factors enhancing the virulence of serovar Typhi under the host acidic conditions and may prove to be helpful in designing the prophylactic measures.
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Rishi P, Rampuria A, Tewari R, Koul A. Phytomodulatory potentials of Aloe vera against Salmonella OmpR-mediated inflammation. Phytother Res 2008; 22:1075-82. [DOI: 10.1002/ptr.2458] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Chanana V, Majumdar S, Rishi P. Involvement of caspase-3, lipid peroxidation and TNF-alpha in causing apoptosis of macrophages by coordinately expressed Salmonella phenotype under stress conditions. Mol Immunol 2006; 44:1551-8. [PMID: 17027970 DOI: 10.1016/j.molimm.2006.08.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Revised: 08/14/2006] [Accepted: 08/22/2006] [Indexed: 11/26/2022]
Abstract
Invasive Salmonella has been reported to induce apoptosis of macrophages as a part of its infection process, which may allow it to avoid detection by the innate immune system. However, the bacterial components capable of inducing apoptosis, particularly under the environments offered by the host have not been fully identified. Therefore, in the present study, attempts were made to evaluate the apoptotic potential of Salmonella enterica serovar Typhi (S. typhi) outer membrane protein expressed under stress conditions like iron, oxidative and anaerobic simulating the in vivo situations encountered by the pathogen. Analysis of data revealed that a coordinately expressed 69kDa outer membrane protein (OMP) expressed with enhanced intensity under iron, oxidative and anaerobic stress conditions caused apoptotic cell death in 51% of macrophages, whereas OMPs of S. typhi extracted under normal conditions accounted for apoptotic cell death in only 31% of macrophages. A significantly enhanced activity of caspase-3 was observed during macrophage-apoptosis induced by this protein. A significant increase in the extent of lipid peroxidation (levels of oxidant) and decrease in the activities of antioxidants was also observed which correlated with the increased generation of tumor necrosis factor-alpha, interleukine-1alpha and interleukine-6. These results suggest that caspase-3 and tumor necrosis factor-alpha in conjunction with other cytokines may induce apoptotic cell death through the up-regulation of oxidants and down-regulation of antioxidants. These findings may be relevant for the better understanding of the disease pathophysiology and for the future developments of diagnostic and preventive strategies during the host-pathogen interactions.
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Affiliation(s)
- Vishal Chanana
- Department of Microbiology, Panjab University, Chandigarh, India
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Chanana V, Majumdar S, Rishi P. Tumour necrosis factor alpha mediated apoptosis in murine macrophages by Salmonella enterica serovar Typhi under oxidative stress. ACTA ACUST UNITED AC 2006; 47:278-86. [PMID: 16831216 DOI: 10.1111/j.1574-695x.2006.00090.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Invasive Salmonella has been reported to induce apoptosis of macrophages as part of its infection process, which may allow it to avoid detection by the innate immune system. However, the induction of apoptosis under the different host environments remains to be examined, including the oxidative stress experienced by pathogens in the macrophage milieu. To simulate in vivo oxidative conditions, Salmonella enterica serovar Typhi was grown in the presence of hydrogen peroxide and its ability to induce apoptosis of murine macrophages was assessed. Analysis of data revealed that oxidative stressed S. Typhi caused apoptotic cell death in 51% of macrophages, whereas S. Typhi grown under normal conditions accounted for apoptotic cell death in only 32% of macrophages. A significant increase in the levels of oxidants and decrease in the antioxidant was also observed which correlated with the increased generation of tumour necrosis factor alpha, interleukin-1alpha and interleukin-6. These results suggest that tumour necrosis factor alpha in conjunction with other cytokines may induce apoptotic cell death through the up-regulation of lipid peroxidation and down-regulation of superoxide dismutase. This finding may help us to understand better the host-pathogen interactions and may be of clinical importance in the development of preventive intervention against infection.
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Affiliation(s)
- Vishal Chanana
- Department of Microbiology, Panjab University, Chandigarh, India
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Rishi P, Kaur H, Tirkey N, Chopra K, Bharrhan S, Chanana V, Koul A. Are the increases in local tumour necrosis factor and lipid peroxidation observed in pre-starved mice infected with Salmonella typhimurium markers of increased liver damage? Microbes Infect 2006; 8:1695-701. [PMID: 16807038 DOI: 10.1016/j.micinf.2006.01.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Revised: 01/20/2006] [Accepted: 01/30/2006] [Indexed: 10/24/2022]
Abstract
Pathogenic microorganisms are known to sense and process signals within their hosts, including those resulting from starvation. Therefore, an attempt was made to evaluate the extent and the possible underlying mechanism of Salmonella typhimurium-induced hepatic damage using pre-starved laboratory mice. The following parameters were analysed, comparing control, fed infected, starved, and starved infected mice: the bacterial load in the liver, fluctuations in liver-derived enzymes alanine-aminotransferase and aspartate-aminotransferase, histopathological changes, lipid peroxidation as well as estimation of reduced glutathione, superoxide dismutase and catalase, along with the TNF content in livers. The number of bacterial cells recovered from starved infected livers at 3 days post-S. typhimurium inoculation was comparable to the number recovered from fed infected livers at 5 days post-Salmonella inoculation, indicating an early increase in the development of the bacteria in starved mice. A marked elevation in liver-derived enzymes in mouse serum and significant histopathological changes are markers of liver damage of higher amplitude in starved infected mice. Analysis of the liver indicated a significant increase in lipid peroxidation in starved infected mice compared to their control counterparts, a process coupled with increased TNF level. Although the reduced glutathione levels showed a marked increase in the starved infected mice, there was a significant decrease in superoxide dismutase and catalase activities in this group.
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Affiliation(s)
- Praveen Rishi
- Department of Microbiology, Basic Medical Sciences Block, Panjab University, Chandigarh, India.
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Chander H, Majumdar S, Sapru S, Rishi P. 55 kDa outer-membrane protein from short-chain fatty acids exposed Salmonella enterica serovar Typhi induces apoptosis in macrophages. Antonie van Leeuwenhoek 2006; 89:317-23. [PMID: 16779627 DOI: 10.1007/s10482-005-9033-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/21/2005] [Indexed: 11/24/2022]
Abstract
Various pathogens including Salmonella species are known to induce apoptosis in host cell types during their infection processes. However, the bacterial components capable of inducing apoptosis have not been fully understood. It is now known that in vivo expression of virulence determinants differ from the expression under in vitro conditions. Therefore, in the present study, attempts were made to evaluate the apoptotic potential of outer-membrane protein (OMP) from short-chain fatty acids (SCFA) exposed Salmonella enterica serovar Typhi. Short-chain fatty acids exposure is one of the in vivo stresses encountered by the pathogen in the intestine. Therefore, to simulate the in vivo condition, S. enterica serovar Typhi was grown in the presence of SCFA and its OMP profile was analyzed. The apoptotic potential of 55 kDa protein expressed with enhanced intensity under the SCFA stress was evaluated. Murine peritoneal macrophages interacted with 55 kDa protein showed DNA fragmentation, changes in fluorescence and exposure of phosphatidylserine on their outer leaflets. Levels of nitrite and citrulline were found to be increased in the supernatant of macrophages after interacting them with 55 kDa protein. However, the enzymatic activity of superoxide dismutase was found to be decreased as compared to that of the control (uninteracted) macrophages. These observations indicate that increased levels of nitrite and decreased levels of superoxide dismutase may be one of the mechanisms to induce apoptosis in macrophages by SCFA induced 55 kDa OMP. These findings may help us better understand the pathophysiology of the disease during the host pathogen interactions.
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Affiliation(s)
- Harish Chander
- Department of Microbiology, Panjab University, Chandigarh, India
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Chanana V, Majumdar S, Ray P, Sharma M, Rishi P. Coordinated expression and immunogenicity of an outer membrane protein from Salmonella enterica serovar Typhi under iron limitation, oxidative stress and anaerobic conditions. J Biomed Sci 2005; 13:303-12. [PMID: 16362827 DOI: 10.1007/s11373-005-9047-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Accepted: 10/24/2005] [Indexed: 11/28/2022] Open
Abstract
Successful pathogens overcome the environmental stresses by the coordinated expression of various genes and eventually proteins. Since, the surface of the microbe is likely to come in contact with the host initially, an attempt was made to identify the outer membrane proteins (OMPs), if any, which may get expressed under more than one environmental conditions simulating the in vivo ones. In the present study, Salmonella enterica serovar Typhi was grown under iron-limited, oxidative stress as well as anaerobic conditions and the OMP profiles were compared. A 69 kDa OMP was found to express with enhanced intensity under the selected stress conditions in comparison to normal conditions. The phenotypic similarity among the proteins was assessed on the basis of their molecular weight, cross reactivity and HPLC. The protein expressed under oxidative stress and anaerobic conditions reacted with the antibodies raised against iron-regulated outer membrane protein (IROMP), indicating the sharing of at least some of the epitopes. A single peak observed after subjecting the pooled 69 kDa protein sample and appearance of a single band on SDS-PAGE thereafter, confirmed the purity and phenotypic similarity of the 69 kDa OMP. Reactivity of pooled 69 kDa protein with 85% of sera from typhoid patients revealed the in vivo expression of this protein. The results of this study indicate the coordination of this phenotype under iron stress, oxidative stress and anaerobic conditions. In view of the expression of the 69 kDa protein under the selected stress conditions and their in vivo immunogenicity, these findings may be relevant for the better understanding of the host-microbe interactions and for the further development of diagnostic and preventive strategies.
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Affiliation(s)
- V Chanana
- Department of Microbiology, Panjab University, Chandigarh, India
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Sood S, Rishi P, Vohra H, Sharma S, Ganguly NK. Cellular immune response induced by Salmonella enterica serotype Typhi iron-regulated outer-membrane proteins at peripheral and mucosal levels. J Med Microbiol 2005; 54:815-821. [PMID: 16091431 DOI: 10.1099/jmm.0.46042-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The role of purified iron-regulated outer-membrane proteins (IROMPs) from Salmonella enterica serotype Typhi in modulation of specific T-cell responses was studied. The cellular immune response induced by IROMPs was measured by assessing the delayed-type hypersensitivity (DTH) response, lymphocyte proliferation, T-cell phenotyping and cytokine-producing cells using lymphocytes isolated from the spleen and Peyer's patches of IROMPs-immunized, immunized-challenged, infected and control mice. IROMPs immunization resulted in an enhanced DTH response and exhibited a significant increase in the protein-specific proliferative response of lymphocyte from the spleen as well as Peyer's patches. A significant increase was also observed in the ratio of CD4+/CD8+ cells in the immunized mice as compared to the infected mice. Results of the cytokine analysis revealed that during the initial period there was increased production of interleukin (IL)-2- and interferon (IFN)-gamma-producing cells in the spleen and Peyer's patches, indicating a Th1 type response, whereas in the later period of the study, increased production of IL-4-producing cells suggested a Th2 type response. The results of this study suggest a role for S. Typhi IROMPs in modulating the cellular immune response at peripheral and mucosal levels.
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Affiliation(s)
- Shaloo Sood
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India 2Department of Microbiology, Panjab University, Chandigarh 160 014, India
| | - Praveen Rishi
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India 2Department of Microbiology, Panjab University, Chandigarh 160 014, India
| | - Harpreet Vohra
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India 2Department of Microbiology, Panjab University, Chandigarh 160 014, India
| | - Saroj Sharma
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India 2Department of Microbiology, Panjab University, Chandigarh 160 014, India
| | - Nirmal K Ganguly
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India 2Department of Microbiology, Panjab University, Chandigarh 160 014, India
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