1
|
Baruah N, Ahamad N, Maiti S, Howlader DR, Bhaumik U, Patil VV, Chakrabarti MK, Koley H, Katti DS. Development of a Self-Adjuvanting, Cross-Protective, Stable Intranasal Recombinant Vaccine for Shigellosis. ACS Infect Dis 2021; 7:3182-3196. [PMID: 34734708 DOI: 10.1021/acsinfecdis.1c00345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
With the acquirement of antibiotic resistance, Shigella has resulted in multiple epidemics of shigellosis, an infectious diarrheal disease, causing thousands of deaths per year. Unfortunately, there are no licensed vaccines, primarily due to low or serotype-specific immunogenicity. Thus, conserved subunit vaccines utilizing recombinant invasion plasmid antigens (Ipa) have been explored as cross-protective vaccine candidates. However, achieving cross-protection against Shigella dysenteriae 1, which caused multiple pandemics/epidemics in the recent past, has been difficult. Therefore, a rational approach to improve cross-protection in the preparation for a possible pandemic should involve conserved proteins from S. dysenteriae 1 (Sd1). IpaC is one such conserved immunogenic protein that is less explored as an independent vaccine due to its instability/aggregation. Therefore, to improve cross-protection and potential immunogenicity and to be prepared for a future epidemic/pandemic, herein, we stabilized recombinant Sd1 IpaC, expressed without its chaperone, using a previously reported stabilizing detergent (LDAO) in a modified protocol and assessed its vaccine potential without an adjuvant. The protein assembled into heterogeneous complex spherical structures in the presence of LDAO and showed improved stability at storage temperatures of -80, -20, 4, 25, and 37 °C while providing enhanced yield and concentration. The protein could also be stably lyophilized and reconstituted, increasing the convenience of transportation and storage. Upon intranasal administration in BALB/c mice, the stabilized-IpaC-immunized groups generated significant antibody response and were not only protected against a high intraperitoneal dose of homologous S. dysenteriae 1 but also showed 100% survival against heterologous Shigella flexneri 2a without an adjuvant, while the control animals showed visible diarrhea (bloody-Sd1 challenge), lethargy, and weight loss with 0% survival. Overall, this work demonstrates that stabilized IpaC can be explored as a minimalist, self-adjuvanting, cross-protective, intranasal, single-antigen Shigella vaccine.
Collapse
Affiliation(s)
- Namrata Baruah
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
- The Mehta Family Centre for Engineering in Medicine, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Nadim Ahamad
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Suhrid Maiti
- Division of Bacteriology, ICMR-National Institute of Cholera & Enteric Diseases, P-33 CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, West Bengal, India
| | - Debaki R. Howlader
- Division of Bacteriology, ICMR-National Institute of Cholera & Enteric Diseases, P-33 CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, West Bengal, India
| | - Ushasi Bhaumik
- Division of Bacteriology, ICMR-National Institute of Cholera & Enteric Diseases, P-33 CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, West Bengal, India
| | - Vinod V. Patil
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Manoj K. Chakrabarti
- Division of Bacteriology, ICMR-National Institute of Cholera & Enteric Diseases, P-33 CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, West Bengal, India
| | - Hemanta Koley
- Division of Bacteriology, ICMR-National Institute of Cholera & Enteric Diseases, P-33 CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, West Bengal, India
| | - Dhirendra S. Katti
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
- The Mehta Family Centre for Engineering in Medicine, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| |
Collapse
|
2
|
Pore D, Mahata N, Chakrabarti MK. Withdrawal: Outer membrane protein A (OmpA) of Shigella flexneri 2a links innate and adaptive immunity in a TLR2-dependent manner and involvement of IL-12 and nitric oxide. J Biol Chem 2020; 295:2543. [DOI: 10.1074/jbc.w120.012819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
3
|
Pore D, Hoque KM, Chakrabarti MK. Animal models in advancement of research in enteric diseases. Anim Biotechnol 2020. [DOI: 10.1016/b978-0-12-811710-1.00032-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
4
|
Adya AK, Agarwal N, Agrawal U, Azevedo V, Bahadur S, Banerjee S, Barh D, Bharadwaj M, Bhatt AN, Bhattacharjee A, Biswas S, Biyani M, Biyani M, Canetta E, Chakrabarti MK, Chanda J, Chandra PK, Chaturvedi R, Chauhan A, Chowbina S, Chowdhuri DK, Chowdhury MR, Das M, Datta A, Dube D, Dubey S, Dutta S, Dwarakanath BSR, Dwivedi PD, Gaur RK, Ghosh P, Gimpel JL, Gupta A, Gupta AK, Gupta M, Gupta UD, Harwansh RK, Hazra R, Hoque KM, Hussain S, Jain P, Jyoti A, Kamal S, Kanjilal S, Kashyap SK, Katiyar CK, Khan FH, Khan ZK, Khanna S, Khurana SMP, Kumar A, Kumar N, Kumar S, Kumar V, Kumar V, Lokman NA, Maherchandani S, Marwal A, Masih S, Maurya PK, Mehrotra R, Mishra A, Mody N, Mondal D, Mukherjee PK, Mukherjee S, Nalluri JJ, Nishigaki K, Nishu N, Oehler MK, Patel B, Pore D, Purushothaman P, Ram KR, Reza Khorramizadeh M, Ricciardelli C, Saadat F, Saha MK, Salawu EO, Shanker R, Sharma R, Singh A, Singh G, Singh M, Singh N, Singh SP, Srivastava P, Suckow MA, Das S, Tripathi R, Upadhyaya KC, Uppal T, Verma AK, Verma A, Verma AS, Verma M, Verma M, Verma M, Verma P, Verma SC, Verma V, Vyas SP, Yadav DK, Yadav N, Yamanaka K, Yiannakopoulou EC. List of Contributors. Anim Biotechnol 2020. [DOI: 10.1016/b978-0-12-811710-1.00043-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
5
|
Affiliation(s)
- Paramita Sarkar
- PathophysiologyNational Institute of Cholera & Enteric DiseasesKolkataIndia
| | - Tultul Saha
- PathophysiologyNational Institute of Cholera & Enteric DiseasesKolkataIndia
| | - Joydeep Aoun
- PathophysiologyNational Institute of Cholera & Enteric DiseasesKolkataIndia
| | | | | | - Shanta K. Dutta
- National Institute of Cholera & Enteric DiseasesKolkataIndia
| | - Kazi Mirajul Hoque
- PathophysiologyNational Institute of Cholera & Enteric DiseasesKolkataIndia
- PhysiologyUniversity of Maryland School of MedicineBaltimoreMD
| |
Collapse
|
6
|
Aoun J, Hayashi M, Sheikh IA, Sarkar P, Saha T, Ghosh P, Bhowmick R, Ghosh D, Chatterjee T, Chakrabarti P, Chakrabarti MK, Hoque KM. Anoctamin 6 Contributes to Cl- Secretion in Accessory Cholera Enterotoxin (Ace)-stimulated Diarrhea: AN ESSENTIAL ROLE FOR PHOSPHATIDYLINOSITOL 4,5-BISPHOSPHATE (PIP2) SIGNALING IN CHOLERA. J Biol Chem 2016; 291:26816-26836. [PMID: 27799301 PMCID: PMC5207189 DOI: 10.1074/jbc.m116.719823] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 10/26/2016] [Indexed: 11/06/2022] Open
Abstract
Accessory cholera enterotoxin (Ace) of Vibrio cholerae has been shown to contribute to diarrhea. However, the signaling mechanism and specific type of Cl- channel activated by Ace are still unknown. We have shown here that the recombinant Ace protein induced ICl of apical plasma membrane, which was inhibited by classical CaCC blockers. Surprisingly, an Ace-elicited rise of current was neither affected by ANO1 (TMEM16A)-specific inhibitor T16A(inh)-AO1(TAO1) nor by the cystic fibrosis transmembrane conductance regulator (CFTR) blocker, CFTR inh-172. Ace stimulated whole-cell current in Caco-2 cells. However, the apical ICl was attenuated by knockdown of ANO6 (TMEM16F). This impaired phenotype was restored by re-expression of ANO6 in Caco-2 cells. Whole-cell patch clamp recordings of ANO currents in HEK293 cells transiently expressing mouse ANO1-mCherry or ANO6-GFP confirmed that Ace induced Cl- secretion. Application of Ace produced ANO6 but not the ANO1 currents. Ace was not able to induce a [Ca2+]i rise in Caco-2 cells, but cellular abundance of phosphatidylinositol 4,5-bisphosphate (PIP2) increased. Identification of the PIP2-binding motif at the N-terminal sequence among human and mouse ANO6 variants along with binding of PIP2 directly to ANO6 in HEK293 cells indicate likely PIP2 regulation of ANO6. The biophysical and pharmacological properties of Ace stimulated Cl- current along with intestinal fluid accumulation, and binding of PIP2 to the proximal KR motif of channel proteins, whose mutagenesis correlates with altered binding of PIP2, is comparable with ANO6 stimulation. We conclude that ANO6 is predominantly expressed in intestinal epithelia, where it contributes secretory diarrhea by Ace stimulation in a calcium-independent mechanism of RhoA-ROCK-PIP2 signaling.
Collapse
Affiliation(s)
- Joydeep Aoun
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Mikio Hayashi
- the Department of Physiology, Kansai Medical University, 5-1, Shimmachi 2, Hirakata, 573 1010 Osaka, Japan
| | - Irshad Ali Sheikh
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Paramita Sarkar
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Tultul Saha
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Priyanka Ghosh
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Rajsekhar Bhowmick
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Dipanjan Ghosh
- the Department of Biotechnology, College of Science and Technology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, India, and
| | - Tanaya Chatterjee
- the Department of Biochemistry, Bose Institute, P-1/12 CIT Road, Scheme-VIIM, Kolkata 700054, India
| | - Pinak Chakrabarti
- the Department of Biochemistry, Bose Institute, P-1/12 CIT Road, Scheme-VIIM, Kolkata 700054, India
| | - Manoj K Chakrabarti
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | - Kazi Mirajul Hoque
- From the Molecular Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India,
| |
Collapse
|
7
|
Nag D, Sinha R, Mitra S, Barman S, Takeda Y, Shinoda S, Chakrabarti MK, Koley H. Heat killed multi-serotype Shigella immunogens induced humoral immunity and protection against heterologous challenge in rabbit model. Immunobiology 2015. [PMID: 26210044 DOI: 10.1016/j.imbio.2015.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recently we have shown the homologous protective efficacy of heat killed multi-serotype Shigella (HKMS) immunogens in a guinea pig colitis model. In our present study, we have advanced our research by immunizing rabbits with a reduced number of oral doses and evaluating the host's adaptive immune responses. The duration of immunogenicity and subsequently protective efficacy was determined against wild type heterologous Shigella strains in a rabbit luminal model. After three successive oral immunizations with HKMS immunogens, serum and lymphocyte supernatant antibody titer against the heterologous shigellae were reciprocally increased and remained at an elevated level up to 180 days. Serogroup and serotype specific O-antigen of lipopolysaccharide and immunogenic proteins of heterologous challenge strains were detected by immunoblot assay. Up-regulation of IL-12p35, IFN-γ and IL-10 mRNA expression was detected in immunized rabbit peripheral blood mononuclear cells (PBMC) after stimulation with HKMS in vitro. HKMS-specific plasma cell response was confirmed by production of a relatively higher level of HKMS-specific IgG in immunized PBMC supernatant compared to control group. Furthermore, the immunized groups of rabbits exhibited complete protection against wild type heterologous shigellae challenge. Thus HKMS immunogens induced humoral and Th1-mediated adaptive immunity and provided complete protection in a rabbit model. These immunogens could be a broad spectrum non-living vaccine candidate for human use in the near future.
Collapse
Affiliation(s)
- Dhrubajyoti Nag
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Ritam Sinha
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Soma Mitra
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Soumik Barman
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Yoshifumi Takeda
- Collaborative Research Centre of Okayama University for Infectious Diseases, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Sumio Shinoda
- Collaborative Research Centre of Okayama University for Infectious Diseases, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - M K Chakrabarti
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Hemanta Koley
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India.
| |
Collapse
|
8
|
Pore D, Chakrabarti MK. Outer membrane protein A (OmpA) from Shigella flexneri 2a: a promising subunit vaccine candidate. Vaccine 2013; 31:3644-50. [PMID: 23764536 DOI: 10.1016/j.vaccine.2013.05.100] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/20/2013] [Accepted: 05/24/2013] [Indexed: 02/08/2023]
Abstract
Shigellosis is the leading cause of childhood mortality and morbidity. Despite many years of extensive research a practical vaccine is not yet available against the disease. Recent studies illustrate that bacterial outer membrane proteins are budding target as vaccine antigen. Outer membrane proteins A (OmpA) are among the most immunodominant antigens in the outer membrane of gram negative bacteria and possess many characteristics desired of a vaccine candidate. We observe that OmpA of Shigella flexneri 2a is crossreactive and common antigen among Shigella spp. and the epitope is widely exposed on the cell surface as well as capable of evoking protective immunity in mice. The protective immunity involves participation of both the humoral and cellular immune responses, since OmpA boosts rapid induction of IgG and IgA in both the systemic and mucosal compartments and also activates Th1 cells. The immunopotentiating activity of OmpA is mediated by its ability to bind and stimulate macrophages and up-regulate the surface expression of MHCII, CD80 and CD40, leading to activation of CD4(+) T cells to secrete cytokines and express chemokine receptor and IL-12Rβ2, thereby orchestrating the bridge between innate and adaptive immune responses. This ability is dependent on Toll-like receptor 2 (TLR2), as demonstrated by lack of response by TLR2 knockdown macrophages to OmpA. Hence this property of OmpA to link innate and adaptive immunity via TLR2 offers a novel vista to develop vaccine against shigellosis.
Collapse
Affiliation(s)
- Debasis Pore
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata 700010, West Bengal, India
| | | |
Collapse
|
9
|
Mitra S, Chakrabarti MK, Koley H. Multi-serotype outer membrane vesicles of Shigellae confer passive protection to the neonatal mice against shigellosis. Vaccine 2013; 31:3163-73. [DOI: 10.1016/j.vaccine.2013.05.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 03/14/2013] [Accepted: 05/01/2013] [Indexed: 12/27/2022]
|
10
|
Sheikh IA, Koley H, Chakrabarti MK, Hoque KM. The Epac1 signaling pathway regulates Cl- secretion via modulation of apical KCNN4c channels in diarrhea. J Biol Chem 2013; 288:20404-15. [PMID: 23720748 DOI: 10.1074/jbc.m113.467860] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The apical membrane of intestinal epithelia expresses intermediate conductance K(+) channel (KCNN4), which provides the driving force for Cl(-) secretion. However, its role in diarrhea and regulation by Epac1 is unknown. Previously we have established that Epac1 upon binding of cAMP activates a PKA-independent mechanism of Cl(-) secretion via stimulation of Rap2-phospholipase Cε-[Ca(2+)]i signaling. Here we report that Epac1 regulates surface expression of KCNN4c channel through its downstream Rap1A-RhoA-Rho-associated kinase (ROCK) signaling pathway for sustained Cl(-) secretion. Depletion of Epac1 protein and apical addition of TRAM-34, a specific KCNN4 inhibitor, significantly abolished cAMP-stimulated Cl(-) secretion and apical K(+) conductance (IK(ap)) in T84WT cells. The current-voltage relationship of basolaterally permeabilized monolayers treated with Epac1 agonist 8-(4-chlorophenylthio)-2'-O- methyladenosine 3',5'-cyclic monophosphate showed the presence of an inwardly rectifying and TRAM-34-sensitive K(+) channel in T84WT cells that was absent in Epac1KDT84 cells. Reconstructed confocal images in Epac1KDT84 cells revealed redistribution of KCNN4c proteins into subapical intracellular compartment, and a biotinylation assay showed ∼83% lower surface expression of KCNN4c proteins compared with T84WT cells. Further investigation revealed that an Epac1 agonist activates Rap1 to facilitate IK(ap). Both RhoA inhibitor (GGTI298) and ROCK inhibitor (H1152) significantly reduced cAMP agonist-stimulated IK(ap), whereas the latter additionally reduced colocalization of KCNN4c with the apical membrane marker wheat germ agglutinin in T84WT cells. In vivo mouse ileal loop experiments showed reduced fluid accumulation by TRAM-34, GGTI298, or H1152 when injected together with cholera toxin into the loop. We conclude that Rap1A-dependent signaling of Epac1 involving RhoA-ROCK is an important regulator of intestinal fluid transport via modulation of apical KCNN4c channels, a finding with potential therapeutic value in diarrheal diseases.
Collapse
Affiliation(s)
- Irshad Ali Sheikh
- Division of Molecular Pathophysiology, National Institute of Cholera and Enteric Diseases, P-33 CIT Road, Scheme-XM, Beliaghata, Kolkata 700010, India
| | | | | | | |
Collapse
|
11
|
Karmakar P, Chakrabarti MK. Thermostable direct hemolysin diminishes tyrosine phosphorylation of epidermal growth factor receptor through protein kinase C dependent mechanism. Biochim Biophys Acta Gen Subj 2012; 1820:1073-80. [PMID: 22543197 DOI: 10.1016/j.bbagen.2012.04.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 04/09/2012] [Accepted: 04/11/2012] [Indexed: 12/20/2022]
Abstract
BACKGROUND Adequate evidence mounts to the fact that several bacteria and their toxins have protective or curative roles in colorectal cancers. Thermostable direct hemolysin (TDH), produced by Vibrio parahaemolyticus, down regulates cell proliferation in colon carcinoma cell lines. TDH induces Ca2+ influx from an extracellular environment accompanied by protein kinase C phosphorylation. Activated protein kinase C inhibits the tyrosine kinase activity of epidermal growth factor receptor (EGFR), the rational target of anti-colorectal cancer therapy. METHODS Immunoblotting analyses were performed to ascertain protein kinase C activation, EGFR status, EGFR phosphorylation and mitogen activated protein kinase (MAPK) activity. Flow cytometry analysis and ELISA reconfirmed tyrosine phosphorylation of EGFR and ERK activations, respectively. PKC-α siRNA knockdown was done to corroborate the involvement of PKC-α in the undertaken study. RESULTS Our study showed the translocation of PKC-α from cytosol to the membrane fraction in colon carcinoma cell lines on incubation with TDH. The EGFR tyrosine kinase activity exhibited a down regulation on TDH treatment which involved PKC-α, as confirmed by siRNA knockdown. Also ERK phosphorylation occurred on PKC-α activation. CONCLUSION TDH activated PKC-α down regulates EGFR tyrosine kinase activity by MEK dependent mechanism involving MAPK. GENERAL SIGNIFICANCE In this study we have seen that TDH has an implication in EGFR based therapeutic approach in colorectal cancer via PKC mediated mechanism.
Collapse
Affiliation(s)
- Poulomee Karmakar
- National Institute of Cholera and Enteric Diseases, Scheme-XM, Beliaghata, Kolkata, India
| | | |
Collapse
|
12
|
Pore D, Mahata N, Chakrabarti MK. Outer membrane protein A (OmpA) of Shigella flexneri 2a links innate and adaptive immunity in a TLR2-dependent manner and involvement of IL-12 and nitric oxide. J Biol Chem 2012; 287:12589-601. [PMID: 22343631 DOI: 10.1074/jbc.m111.335554] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We determine that OmpA of Shigella flexneri 2a is recognized by TLR2 and consequently mediates the release of proinflammatory cytokines and activates NF-κB in HEK 293 cells transfected with TLR2. We also observe that in RAW macrophages TLR2 is essential to instigate the early immune response to OmpA via NF-κB activation and secretion of cytokines and NO. Consistent with these results, TLR2 knockdown using siRNA abolishes the initiation of immune responses. Processing and presentation of OmpA depend on TLR2; MHCII presentation of the processed antigen and expression of CD80 significantly attenuated in TLR2 knockdown macrophages. The optimum production of IFN-γ by the macrophages:CD4(+) T cells co-culture depends on both TLR2 activation and antigen presentation. So, TLR2 is clearly recognized as a decisive factor in initiating host innate immune response to OmpA for the development of CD4(+) T cell adaptive response. Furthermore, we demonstrate in vivo that intranasal immunization of mice with OmpA selectively enhances the release of IFN-γ and IL-2 by CD4(+) T cells. Importantly, OmpA increases the level of IFN-γ production in Ag-primed splenocytes. The addition of neutralizing anti-IL-12p70 mAb to cell cultures results in the decreased release of OmpA-enhanced IFN-γ by Ag-primed splenocytes. Moreover, coincubation with OmpA-pretreated macrophages enhances the production of IFN-γ by OmpA-primed CD4(+) T cells, representing that OmpA may enhance IFN-γ expression in CD4(+) T cells through the induction of IL-12 production in macrophages. These results demonstrate that S. flexneri 2a OmpA may play a critical role in the development of Th1 skewed adaptive immune response.
Collapse
Affiliation(s)
- Debasis Pore
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata 700010, West Bengal, India
| | | | | |
Collapse
|
13
|
Pore D, Mahata N, Pal A, Chakrabarti MK. Outer membrane protein A (OmpA) of Shigella flexneri 2a, induces protective immune response in a mouse model. PLoS One 2011; 6:e22663. [PMID: 21818362 PMCID: PMC3144247 DOI: 10.1371/journal.pone.0022663] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 06/28/2011] [Indexed: 02/03/2023] Open
Abstract
Background In our earlier studies 34 kDa outer membrane protein (OMP) of Shigella flexneri 2a has been identified as an efficient immunostimulant. Key Results In the present study MALDI-TOF MS analysis of the purified 34 kDa OMP of Shigella flexneri 2a shows considerable sequence homology (Identity 65%) with the OmpA of S. flexneri 2a. By using the specific primers, the gene of interest has been amplified from S. flexneri 2a (N.Y-962/92) genomic DNA, cloned in pET100/D-TOPO® vector and expressed using induction with isopropyl thiogalactoside (IPTG) for the first time. Immunogenicity and protective efficacy of the recombinant OmpA has been evaluated in an intranasally immunized murine pulmonary model. The recombinant protein induces significantly enhanced protein specific IgG and IgA Abs in both mucosal and systemic compartments and IgA secreting cells in the systemic compartment (spleen). The mice immunized with OmpA have been protected completely from systemic challenge with a lethal dose of virulent S. flexneri 2a. Immunization with the protein causes mild polymorphonuclear neutrophil infiltration in the lung, without inducing the release of large amounts of proinflammatory cytokines. Conclusion These results suggest that the OmpA of S. flexneri 2a can be an efficacious mucosal immunogen inducing protective immune responses. Our findings also demonstrate that antibodies and Th1 immune response may be associated with the marked protective efficacy of immunized mice after intranasal shigellae infection.
Collapse
Affiliation(s)
- Debasis Pore
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, West Bengal, India
| | - Nibedita Mahata
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, West Bengal, India
| | - Amit Pal
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, West Bengal, India
| | - Manoj K. Chakrabarti
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, West Bengal, India
- * E-mail:
| |
Collapse
|
14
|
Chowdhury P, Pore D, Mahata N, Karmakar P, Pal A, Chakrabarti MK. Thermostable direct hemolysin downregulates human colon carcinoma cell proliferation with the involvement of E-cadherin, and β-catenin/Tcf-4 signaling. PLoS One 2011; 6:e20098. [PMID: 21625458 PMCID: PMC3098874 DOI: 10.1371/journal.pone.0020098] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 04/21/2011] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Colon cancers are the frequent causes of cancer mortality worldwide. Recently bacterial toxins have received marked attention as promising approaches in the treatment of colon cancer. Thermostable direct hemolysin (TDH) secreted by Vibrio parahaemolyticus causes influx of extracellular calcium with the subsequent rise in intracellular calcium level in intestinal epithelial cells and it is known that calcium has antiproliferative activity against colon cancer. KEY RESULTS In the present study it has been shown that TDH, a well-known traditional virulent factor inhibits proliferation of human colon carcinoma cells through the involvement of CaSR in its mechanism. TDH treatment does not induce DNA fragmentation, nor causes the release of lactate dehydrogenase. Therefore, apoptosis and cytotoxicity are not contributing to the TDH-mediated reduction of proliferation rate, and hence the reduction appears to be caused by decrease in cell proliferation. The elevation of E-cadherin, a cell adhesion molecule and suppression of β-catenin, a proto-oncogene have been observed in presence of CaSR agonists whereas reverse effect has been seen in presence of CaSR antagonist as well as si-RNA in TDH treated cells. TDH also triggers a significant reduction of Cyclin-D and cdk2, two important cell cycle regulatory proteins along with an up regulation of cell cycle inhibitory protein p27(Kip1) in presence of CaSR agonists. CONCLUSION Therefore TDH can downregulate colonic carcinoma cell proliferation and involves CaSR in its mechanism of action. The downregulation occurs mainly through the involvement of E-cadherin-β-catenin mediated pathway and the inhibition of cell cycle regulators as well as upregulation of cell cycle inhibitors.
Collapse
Affiliation(s)
- Pinki Chowdhury
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, India
| | - Debasis Pore
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, India
| | - Nibedita Mahata
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, India
| | - Poulomee Karmakar
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, India
| | - Amit Pal
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, India
| | - Manoj K. Chakrabarti
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, India
| |
Collapse
|
15
|
Syngkon A, Elluri S, Koley H, Rompikuntal PK, Saha DR, Chakrabarti MK, Bhadra RK, Wai SN, Pal A. Studies on a novel serine protease of a ΔhapAΔprtV Vibrio cholerae O1 strain and its role in hemorrhagic response in the rabbit ileal loop model. PLoS One 2010; 5. [PMID: 20927349 PMCID: PMC2948034 DOI: 10.1371/journal.pone.0013122] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 09/03/2010] [Indexed: 01/22/2023] Open
Abstract
Background Two well-characterized proteases secreted by Vibrio cholerae O1 strains are hemagglutinin protease (HAP) and V. cholerae protease (PrtV). The hapA and prtV knock out mutant, V. cholerae O1 strain CHA6.8ΔprtV, still retains residual protease activity. We initiated this study to characterize the protease present in CHA6.8ΔprtV strain and study its role in pathogenesis in rabbit ileal loop model (RIL). Methodology/Principal Findings We partially purified the residual protease secreted by strain CHA6.8ΔprtV from culture supernatant by anion-exchange chromatography. The major protein band in native PAGE was identified by MS peptide mapping and sequence analysis showed homology with a 59-kDa trypsin-like serine protease encoded by VC1649. The protease activity was partially inhibited by 25 mM PMSF and 10 mM EDTA and completely inhibited by EDTA and PMSF together. RIL assay with culture supernatants of strains C6709 (FA ratio 1.1+/−0.3 n = 3), CHA6.8 (FA ratio 1.08+/−0.2 n = 3), CHA6.8ΔprtV (FA ratio 1.02+/−0.2 n = 3) and partially purified serine protease from CHA6.8ΔprtV (FA ratio 1.2+/−0.3 n = 3) induced fluid accumulation and histopathological studies on rabbit ileum showed destruction of the villus structure with hemorrhage in all layers of the mucosa. RIL assay with culture supernatant of CHA6.8ΔprtVΔVC1649 strain (FA ratio 0.11+/−0.005 n = 3) and with protease incubated with PMSF and EDTA (FA ratio 0.3+/−0.05 n = 3) induced a significantly reduced FA ratio with almost complete normal villus structure. Conclusion Our results show the presence of a novel 59-kDa serine protease in a ΔhapAΔprtV V. cholerae O1 strain and its role in hemorrhagic response in RIL model.
Collapse
Affiliation(s)
- Aurelia Syngkon
- Divisions of Pathophysiology, National Institute of Cholera and Enteric Diseases, Kolkata, West Bengal, India
| | - Sridhar Elluri
- Divisions of Pathophysiology, National Institute of Cholera and Enteric Diseases, Kolkata, West Bengal, India
- Department of Molecular Biology, Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Hemanta Koley
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, West Bengal, India
| | - Pramod K. Rompikuntal
- Department of Molecular Biology, Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Dhira Rani Saha
- Division of Histology and Electron Microscopy, National Institute of Cholera and Enteric Diseases, Kolkata, West Bengal, India
| | - Manoj K. Chakrabarti
- Divisions of Pathophysiology, National Institute of Cholera and Enteric Diseases, Kolkata, West Bengal, India
| | - Rupak K. Bhadra
- Infectious Diseases and Immunology Division, Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Sun Nyunt Wai
- Department of Molecular Biology, Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Amit Pal
- Divisions of Pathophysiology, National Institute of Cholera and Enteric Diseases, Kolkata, West Bengal, India
- * E-mail:
| |
Collapse
|
16
|
Mahata N, Pore D, Pal A, Chakrabarti MK. Reorganization of cytoskeletal proteins by Escherichia coli heat-stable enterotoxin (STa)-mediated signaling cascade. Biochim Biophys Acta Gen Subj 2010; 1800:591-8. [PMID: 20338221 DOI: 10.1016/j.bbagen.2010.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 03/08/2010] [Accepted: 03/10/2010] [Indexed: 11/17/2022]
Abstract
BACKGROUND IP(3)-mediated calcium mobilization from intracellular stores activates and translocates PKC-alpha from cytosol to membrane fraction in response to STa in COLO-205 cell line. The present study was undertaken to determine the involvement of cytoskeleton proteins in translocation of PKC-alpha to membrane from cytosol in the Escherichiacoli STa-mediated signaling cascade in a human colonic carcinoma cell line COLO-205. METHODS Western blots and consequent densitometric analysis were used to assess time-dependent redistribution of cytoskeletal proteins. This redistribution was further confirmed by using confocal microscopy. Pharmacological reagents were applied to colonic carcinoma cells to disrupt the microfilaments (cytochalasin D) and microtubules (nocodazole). RESULTS STa treatment in COLO-205 cells showed dynamic redistribution and an increase in actin content in the Triton-insoluble fraction, which corresponds to an increase in polymerization within 1min. Moreover, pharmacological disruption of actin-based cytoskeleton greatly disturbed PKC-alpha translocation to the membrane. CONCLUSIONS These results suggested that the organization of actin cytoskeleton is rapidly rearranged following E. coli STa treatment and the integrity of the actin cytoskeleton played a crucial role in PKC-alpha movement in colonic cells. Depolymerization of tubulin had no effect on the ability of the kinase to be translocated to the membrane. GENERAL SIGNIFICANCE In the present study, we have shown for the first time that in colonic carcinoma cells, STa-mediated rapid changes of actin cytoskeleton arrangement might be involved in the translocation of PKC-alpha to membrane.
Collapse
Affiliation(s)
- Nibedita Mahata
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata-700010, West Bengal, India
| | | | | | | |
Collapse
|
17
|
Pore D, Chowdhury P, Mahata N, Pal A, Yamasaki S, Mahalanabis D, Chakrabarti MK. Purification and characterization of an immunogenic outer membrane protein of Shigella flexneri 2a. Vaccine 2009; 27:5855-64. [PMID: 19660587 DOI: 10.1016/j.vaccine.2009.07.054] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 07/13/2009] [Accepted: 07/18/2009] [Indexed: 10/20/2022]
Abstract
In the present study we purified 34 kDa major outer membrane protein (MOMP) of Shigella flexneri 2a for the first time, which was cross-reactive and antigenically conserved among Shigella spp. and the epitope was surface exposed on the intact bacterium. The purified antigen was found to be glycosylated, which aids in binding to macrophages and up-regulated the production of nitric oxide, granulocyte-colony stimulating factor and IL-12p70, indicating that the MOMP is immunogenic and has the ability to commence protective immune responses against intracellular pathogens, thereby it may be considered as a potential vaccine candidate.
Collapse
Affiliation(s)
- Debasis Pore
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata 700010, West Bengal, India
| | | | | | | | | | | | | |
Collapse
|
18
|
Saha S, Chowdhury P, Pal A, Chakrabarti MK. Downregulation of human colon carcinoma cell (COLO-205) proliferation through PKG-MAP kinase mediated signaling cascade by E. coli heat stable enterotoxin (STa), a potent anti-angiogenic and anti-metastatic molecule. J Appl Toxicol 2008; 28:475-83. [PMID: 17828804 DOI: 10.1002/jat.1297] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It was reported earlier that Escherichia coli heat stable enterotoxin (STa), a major causative agent of secretory diarrhea, can also inhibit the proliferation of colon carcinoma cells with the involvement of cGMP mediated calcium influx. In the present study it is shown that E. coli STa inhibits cell proliferation in the colonic carcinoma cell line COLO-205 by the PKG-ERK44/42 mediated signaling pathway. This enterotoxin negatively regulates cell proliferation by downregulating the activity of ERK44/42(MAPK) and subsequently the activity of a transcription regulatory protein cMyc. The antiproliferative effect of STa was reversed by LY83583, a guanylate cyclase (GC) inhibitor and KT5823, a PKG inhibitor. Thus suggesting the involvement of cGMP dependent protein kinase (PKG) in the downregulation of ERK44/42 and subsequent inactivation of cMyc activity. Moreover, it has been shown that a specific ERK44/42 inhibitor, PD98059, also inhibits cMyc activation and cell proliferation, which further confirms the involvement of ERK44/42 in the activation of cMyc. It is also shown that E. coli STa significantly inhibits the vascular endothelial growth factor (VEGF, a potent angiogenic factor) expression in COLO-205 cells and also downregulates vascular cell adhesion molecule-1 (VCAM-1, a potent metastatic factor) expression on the COLO-205 cell surface. So it is reported for the first time that E. coli STa inhibits the proliferation of the colonic carcinoma cell line COLO-205 by the PKG-ERK44/42 mediated pathway and it may have a role against the development of colon carcinoma.
Collapse
Affiliation(s)
- Subhrajit Saha
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Calcutta 700010, India
| | | | | | | |
Collapse
|
19
|
Saha S, Chowdhury P, Mazumdar A, Pal A, Das P, Chakrabarti MK. Role of Yersinia enterocolitica heat-stable enterotoxin (Y-STa) on differential regulation of nuclear and cytosolic calcium signaling in rat intestinal epithelial cells. Cell Biol Toxicol 2008; 25:297-308. [PMID: 18563600 DOI: 10.1007/s10565-008-9084-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Accepted: 04/22/2008] [Indexed: 01/11/2023]
Abstract
The heat-stable enterotoxin (Y-STa) produced by the pathogenic strains of Yersinia enterocolitica is a causative agent of secretory diarrhea. We have reported earlier that Y-STa-induced inositol trisphosphate-mediated cytosolic calcium rise occurs in rat intestinal epithelial cells. In the present communication, the involvement of a nuclear calcium store in the action mechanism of Y-STa in rat intestinal epithelial cells has been shown. Calcium imaging with time series confocal microscopy shows that Y-STa stimulates both the nuclear and cytosolic calcium levels in rat intestinal epithelial cells where a rise in nuclear calcium precedes the cytosolic events. Moreover, Y-STa stimulates both cytosolic and nuclear inositol trisphosphate (IP(3)) levels in a time-dependent manner. Western blot and immunocytochemical analysis reveal a higher density of IP(3) receptor type II in the nuclear membrane compared to the cytosol, which may be the cause of an early rise of the nuclear calcium level. Therefore, it is suggested that Y-STa regulates the nuclear and cytosolic calcium signals in a distinct temporal manner in rat intestinal epithelial cells.
Collapse
Affiliation(s)
- Subhrajit Saha
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Calcutta, India
| | | | | | | | | | | |
Collapse
|
20
|
Ghosh A, Saha DR, Hoque KM, Asakuna M, Yamasaki S, Koley H, Das SS, Chakrabarti MK, Pal A. Enterotoxigenicity of mature 45-kilodalton and processed 35-kilodalton forms of hemagglutinin protease purified from a cholera toxin gene-negative Vibrio cholerae non-O1, non-O139 strain. Infect Immun 2006; 74:2937-46. [PMID: 16622232 PMCID: PMC1459690 DOI: 10.1128/iai.74.5.2937-2946.2006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Revised: 10/14/2005] [Accepted: 02/14/2006] [Indexed: 11/20/2022] Open
Abstract
Cholera toxin gene-negative Vibrio cholerae non-O1, non-O139 strain PL-21 is the etiologic agent of cholera-like syndrome. Hemagglutinin protease (HAP) is one of the major secretory proteins of PL-21. The mature 45-kDa and processed 35-kDa forms of HAP were purified in the presence and absence of EDTA from culture supernatants of PL-21. Enterotoxigenicities of both forms of HAP were tested in rabbit ileal loop (RIL), Ussing chamber, and tissue culture assays. The 35-kDa HAP showed hemorrhagic fluid response in a dose-dependent manner in the RIL assay. Histopathological examination of 20 microg of purified protease-treated rabbit ileum showed the presence of erythrocytes and neutrophils in the upper part of the villous lamina propria. Treatment with 40 microg of protease resulted in gross damage of the villous epithelium with inflammation, hemorrhage, and necrosis. The 35-kDa form of HAP, when added to the lumenal surface of rat ileum loaded in an Ussing chamber, showed a decrease in the intestinal short-circuit current and a cell rounding effect on HeLa cells. The mature 45-kDa form of HAP showed an increase in intestinal short-circuit current in an Ussing chamber and a cell distending effect on HeLa cells. These results show that HAP may play a role in the pathogenesis of PL-21.
Collapse
Affiliation(s)
- A Ghosh
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Calcutta 700010, West Bengal, India
| | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Mukhopadhaya A, Mahalanabis D, Chakrabarti MK. Role of Shigella flexneri 2a 34 kDa outer membrane protein in induction of protective immune response. Vaccine 2006; 24:6028-36. [PMID: 16765491 DOI: 10.1016/j.vaccine.2006.03.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Revised: 03/07/2006] [Accepted: 03/14/2006] [Indexed: 11/26/2022]
Abstract
Emergence of Shigella vaccine is in great need in developing countries. In this paper we have shown that 34 kDa Shigella flexneri 2a outer membrane protein has a role in eliciting immune responses. When injected parentarally this protein gives significant protection against challenge with virulent Shigella flexneri 2a. Macrophages activated with the 34 kDa protein resulted in the dose dependent production of nitric oxide, the highly reactive free radical responsible for killing of invading bacterial pathogen. Also, treatment of murine peritoneal macrophages with the 34 kDa protein showed dose dependent increase in the production of tumor necrosis factor-alpha and interleukin-12. However, there was no dose dependent increase in interleukin-10 production. These data indicated that the 34 kDa outer membrane protein has the ability to modulate the protective immune response against the invading bacterial pathogen, mainly through TH1 mediated pathway. So, the 34 kDa outer mebrane protein can be one of the major components for developing subunit vaccine against shigellosis.
Collapse
Affiliation(s)
- A Mukhopadhaya
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata 700010, West Bengal, India
| | | | | |
Collapse
|
22
|
Chakrabarti MK, Haque KM, Chakrabarty M, Mahalanabis D. Effect of reducing sodium or glucose concentration in a hypo-osmolar ORS (oral rehydration salts) on absorption efficiency: marker perfusion study in rat jejunum. Dig Dis Sci 2005; 50:241-5. [PMID: 15745079 DOI: 10.1007/s10620-005-1589-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
We evaluated the relative absorption efficiency of reducing the sodium or glucose concentration to make an ORS hypo-osmolar in a perfusion model. In nine adult albino rats 30 cm of jejunum was perfused at 0.4 ml/min with three glucose salt solutions for 45 min each, one with 60 mM sodium, 111 mM glucose, and osmolarity 247, one with 90 mM sodium, 60 mM glucose, and osmolarity 250, and one with 90 mM sodium, (111 mM) glucose, and osmolarity 301 (control solution). Each contained 2 g/L polyethylene glycol 4000 as a marker. The net water and sodium absorption were 2.8 (P < 0.001) and 2.6 (P < 0.001) times higher from low-sodium and 1.7 (P < 0.001)- and 1.5 (P < 0.001)-fold higher from low-glucose solutions compared to the control. Net glucose absorption was 2.2 (P < 0.001)-fold higher from low-sodium solutions compared to the control. The net water, sodium, potassium, and glucose absorptions were 1.6 (P < 0.001)-, 1.7 (P < 0.001)-, 1.36 (P < 0.05)-, and 4.15 (P < 0.001)-fold higher from low-sodium compared to low-glucose solutions. The hypo-osmolar ORS with reduced sodium was substantially more absorption efficient compared to the one with reduced glucose.
Collapse
Affiliation(s)
- Manoj K Chakrabarti
- Society for Applied Studies, 108 Manicktala Main Road, Flat-3/21, Calcutta 700 054, India
| | | | | | | |
Collapse
|
23
|
Saha S, Gupta DD, Chakrabarti MK. Involvement of phospholipase C in Yersinia enterocolitica heat stable enterotoxin (Y-STa) mediated rise in intracellular calcium level in rat intestinal epithelial cells. Toxicon 2005; 45:361-7. [PMID: 15683875 DOI: 10.1016/j.toxicon.2004.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Revised: 11/02/2004] [Accepted: 11/03/2004] [Indexed: 11/26/2022]
Abstract
In response to Yersinia enterocolitica heat stable enterotoxin (Y-STa) intracellular calcium level was increased with a prolong sustained phase in presence of calcium chloride in extracellular environment in rat intestinal epithelial cells. Chelation of extracellular calcium with EGTA (extracellular calcium chelator) and suspension of cells in calcium free buffer demonstrated a rapid but transient rise in calcium level, which suggested that Y-STa induced rise in intracellular calcium concentration was the combination of both intracellular calcium store depletion and calcium influx from extracellular environment. Moreover, in response to Y-STa phosphoinositide specific phospholipase C activity and inositol tri phosphate (IP3) level was increased and U73122, a phospholipase C inhibitor could completely inhibit Y-STa induced calcium rise. However, treatment of rat enterocytes with dantrolene IP3, a mediated calcium release inhibitor from intracellular store resulted partial inhibition of Y-STa induced rise in intracellular calcium level. Similar observation was noted with IP3 receptor antagonist 2ABP (2-amino-ethoxydiphenylborate). These results suggested that beside phospholipase C IP3 pathway, phospholipase C might have an independent role in Y-STa induced calcium influx. Rise in phospholipase Cgamma isoform activity in response to Y-STa suggested that gamma isoform of phospholipase C might have a role in Y-STa mediated rise in intracellular calcium level.
Collapse
Affiliation(s)
- Subhrajit Saha
- Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Calcutta 700010, India
| | | | | |
Collapse
|
24
|
Gupta DD, Saha S, Chakrabarti MK. Involvement of protein kinase C in the mechanism of action of Escherichia coli heat-stable enterotoxin (STa) in a human colonic carcinoma cell line, COLO-205. Toxicol Appl Pharmacol 2004; 206:9-16. [PMID: 15963340 DOI: 10.1016/j.taap.2004.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2004] [Revised: 10/28/2004] [Accepted: 11/01/2004] [Indexed: 10/26/2022]
Abstract
The present study was undertaken to determine the involvement of calcium-protein kinase C pathway in the mechanism of action of Escherichia coli heat stable enterotoxin (STa) apart from STa-induced activation of guanylate cyclase in human colonic carcinoma cell line COLO-205, which was used as a model cultured cell line to study the mechanism of action of E. coli STa. In response to E. coli STa, protein kinase C (PKC) activity was increased in a time-dependent manner with its physical translocation from cytosol to membrane. Inhibition of the PKC activity in membrane fraction and inhibition of its physical translocation in response to IP3-mediated calcium release inhibitor dantrolene suggested the involvement of intracellular store depletion in the regulation of PKC activity. Among different PKC isoforms, predominant involvement of calcium-dependent protein kinase C (PKC(alpha)) was specified using isotype-specific pseudosubstrate, which showed pronounce enzyme activity. Inhibition of enzyme activity by PKC(alpha)-specific inhibitor Gö6976 and immunoblott study employing isotype-specific antibody further demonstrated the involvement of calcium-dependent isoform of PKC in the mechanism of action of E. coli STa. Moreover, inhibition of guanylate cyclase activity by PKC(alpha)-specific inhibitor Gö6976 suggested the involvement of PKC(alpha) in the regulation of guanylate cyclase activity.
Collapse
Affiliation(s)
- Dyuti Datta Gupta
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, P-33, C. I. T. Road, Scheme-XM, Beliaghata, Kolkata-700 010, India
| | | | | |
Collapse
|
25
|
Hoque KM, Saha S, Gupta DD, Chakrabarti MK. Role of nitric oxide in NAG-ST induced store-operated calcium entry in rat intestinal epithelial cells. Toxicology 2004; 201:95-103. [PMID: 15297024 DOI: 10.1016/j.tox.2004.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2003] [Revised: 04/15/2004] [Accepted: 04/15/2004] [Indexed: 11/24/2022]
Abstract
This study was undertaken to find out the mechanism of non-agglutinable Vibrio cholerae heat-stable enterotoxin (NAG-ST)-induced calcium influx across the plasma membrane. Adriamycin, an inhibitor of IP3-specific 3-kinase, could not inhibit NAG-ST-induced calcium influx in rat intestinal epithelial cells, which suggested that inositol 1,3,4,5-tetrakisphosphate (IP4) had no role in NAG-ST-induced calcium influx. NAG-ST increased intracellular nitric oxide level of rat enterocytes as measured by a fluorimetric method using a fluoroprobe 4,5-diaminofluorescein-2-diacetate (DAF-2DA). N-Nitro-L-arginine, an inhibitor of nitric oxide synthase, inhibited NAG-ST-induced rise in nitric oxide level and also calcium influx. Inhibition of inositol trisphosphate (IP3)-mediated intracellular calcium mobilization by Dantrolene could also inhibit NAG-ST-induced rise in intracellular nitric oxide level. Moreover, inhibition of soluble guanylate cyclase by inhibitors (ODQ, LY83583) could inhibit the NAG-ST-induced rise in cyclic guanosine-3',5'-monophosphate (cGMP) level and calcium influx. From this study, it is evident that NAG-ST causes IP3-mediated calcium release from intracellular calcium store, which then stimulates nitric oxide production by activating nitric oxide synthase and the nitric oxide through cGMP activates calcium influx.
Collapse
Affiliation(s)
- Kazi Mirazul Hoque
- Pathophysiology Division, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Calcutta 700010, India
| | | | | | | |
Collapse
|
26
|
Mukhopadhaya A, Mahalanabis D, Khanam J, Chakrabarti MK. Protective efficacy of oral immunization with heat-killed Shigella flexneri 2a in animal model: study of cross protection, immune response and antigenic recognition. Vaccine 2003; 21:3043-50. [PMID: 12798648 DOI: 10.1016/s0264-410x(03)00111-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oral immunization of rabbits with four doses of 10(11) heat-killed Shigella flexneri 2a showed 100% protection against challenge with virulent S. flexneri 2a. After orally immunizing Guinea pigs with four doses of heat-killed S. flexneri 2a 100% protection could be shown against ocular challenge with the same virulent S. flexneri 2a strain but this conferred no protection against challenge with Shigella dysenteriae type 1. In enzyme-linked immunosorbent assay (ELISA) and immunoblot experiments both whole cell lysate-envelope (WCL-E) fraction and outer membrane proteins (OMPs) were recognized by the antisera. Though protective mechanism in shigellosis is not established with certainty, outer membrane proteins (specially 38, 34, 23 and 20kDa proteins) may be the major antigens in the induction of protective immune responses as indicated by this observation.
Collapse
Affiliation(s)
- A Mukhopadhaya
- Division of Pathophysiology, National Institute of Cholera & Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata 700010, West Bengal, India
| | | | | | | |
Collapse
|
27
|
Hoque KM, Pal A, Chakrabarti MK. Translocation of protein kinase-C with IP3-induced calcium mobilization by heat-stable enterotoxin of Vibrio cholerae non-O1 in isolated rat enterocytes. Int J Med Microbiol 2003; 293:413-20. [PMID: 14760972 DOI: 10.1078/1438-4221-00279] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The activity of the calcium- and phospholipid-dependent enzyme protein kinase C (PKC) in response to heat-stable enterotoxin (NAG-ST) of Vibrio cholerae non-O1 was examined in isolated rat enterocytes. Optimal stimulation of the membrane-bound PKC activity (about 4.3-fold) was observed after 1 min of incubation of cells with 10 ng/ml toxin; and the effects were dose dependent. Following NAG-ST treatment an increase in PKC activity in the membrane fraction was found with a concomitant decrease in the cytosolic fraction suggesting the redistribution of the enzyme. The pronounced enzyme activity in presence of a classical pseudosubstrate and its complete inhibition by Gö 6976 suggested the involvement of a calcium-dependent isoform of PKC (PKC-alpha). A time course study employing an immunoblot assay provided evidence that NAG-ST led to almost complete translocation of PKC-alpha to the membrane. A 65% inhibition of enzyme activity in the membrane fraction and inhibition of its translocation to some extent by dantrolene treatment further suggested that the enzyme was translocated with the rise of intracellular calcium ([Ca2+]i). The phosphorylation of three membrane proteins by toxin-induced PKC in vitro and abolition of this phosphorylation by Gö 6976 demonstrated that phosphorylation of these membrane proteins was PKC-alpha mediated and might be involved in the alteration of membrane functions.
Collapse
Affiliation(s)
- Kazi Mirajul Hoque
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata, India
| | | | | |
Collapse
|
28
|
Mahalanabis D, Chowdhury A, Jana S, Bhattacharya MK, Chakrabarti MK, Wahed MA, Khaled MA. Zinc supplementation as adjunct therapy in children with measles accompanied by pneumonia: a double-blind, randomized controlled trial. Am J Clin Nutr 2002; 76:604-7. [PMID: 12198006 DOI: 10.1093/ajcn/76.3.604] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Zinc deficiency, common in developing countries, is associated with decreased immunocompetence. Zinc supplementation benefits children with acute and persistent diarrhea and prevents pneumonia. Most deaths from vaccine-preventable diseases are from measles and whooping cough; pneumonia is the most common complication of measles and often the proximate cause of related deaths. OBJECTIVE We evaluated the effect of zinc supplementation on episodes of illness in children with measles accompanied by pneumonia. DESIGN In a double-blind, randomized controlled trial, children aged 9 mo-15 y who were admitted to the Infectious Diseases Hospital in Calcutta with clinically severe measles accompanied by pneumonia and who had been ill for </= 7 d were randomly assigned to receive zinc (20 mg, in elemental form as acetate, twice daily for 6 d) or a placebo. All patients received standard treatment with antibiotics and an initial 100 000-IU dose of vitamin A (as palmitate) by mouth. RESULTS Time-to-event analysis using the Cox proportional hazards model (42 in the zinc group and 43 in the placebo group) showed that the time needed for the resolution of fever and tachypnea, the return of appetite, and the achievement of a "much improved" or "cured" status was not different between the 2 groups. A high proportion of children had low serum retinol and zinc concentrations. Improvement in serum zinc and retinol concentrations after 6 d of treatment was not different between the 2 groups. CONCLUSION Children with severe measles accompanied by pneumonia treated with antibiotics and vitamin A did not show any additional benefit from also receiving a zinc supplement.
Collapse
|
29
|
Hoque KM, Pal A, Nair GB, Chattopadhyay S, Chakrabarti MK. Evidence of calcium influx across the plasma membrane depends upon the initial rise of cytosolic calcium with activation of IP(3) in rat enterocytes by heat-stable enterotoxin of Vibrio cholerae non-O1. FEMS Microbiol Lett 2001; 196:45-50. [PMID: 11257546 DOI: 10.1111/j.1574-6968.2001.tb10538.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In response to heat-stable enterotoxin of Vibrio cholerae non-O1, the initial rise of cytosolic Ca(2+) occurred with activation of IP(3). Chelation of extracellular Ca(2+) with EGTA and suspension of cells in Ca(2+) free buffer both demonstrated the involvement of internal stores in the rise of [Ca(2+)]i. Cells pretreated with dantrolene resulted in decrease of [Ca(2+)]i response which suggested that the rise of intracellular level of Ca(2+) was mostly due to the mobilization from IP(3) sensitive stores. When the cytosolic Ca(2+) was chelated by loading the cells with BAPTA, NAG-ST could not induce Ca(2+) entry to the cell as assessed by Mn(2+) quenching of fura-2 fluorescence which suggested that calcium influx across the plasma membrane depends upon initial rise of this bivalent cation that maintained the sustained phase of [Ca(2+)]i response. Addition of toxin to the fura-2-loaded cells, preincubated with lanthanum chloride, resulted in reduction of [Ca(2+)]i level with a short duration of irregular sustained phase further suggesting that the influx of Ca(2+) across the plasma membrane might be through the calcium channel.
Collapse
Affiliation(s)
- K M Hoque
- Pathophysiology Division, national Institute of Cholera and Enteric Diseases, Calcutta, India
| | | | | | | | | |
Collapse
|
30
|
Bhattacharya J, Samanta S, Hoque KM, Mukherjee A, Chakrabarti MK. Escherichia coli heat stable enterotoxin receptors & guanylyl cyclase activity in the intestinal brush border membrane of hamsters & guinea pigs. Indian J Med Res 2001; 113:5-10. [PMID: 11280169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
BACKGROUND & OBJECTIVES Although Escherichia coli heat stable enterotoxin (STa) causes diarrhoea in laboratory animals, no studies were done to find out the species specific variation of distribution of the STa receptors in laboratory animals. The present investigation evaluates the density of STa receptors and the guanylyl cyclase (GC) activity in the small intestinal epithelial cells of hamsters and guinea pigs. METHODS Brush border membrane (BBM) was prepared from the small intestines of hamsters and guinea pigs. Receptor binding assay, GC assay and autoradiography were performed to determine the density of STa receptors, the GC activity and molecular weights of the STa binding proteins respectively. RESULTS The receptor densities, per mg BBM protein at equilibrium, were found to be 4.1 x 10(9) and 1.5 x 10(12) in hamsters and guinea pigs respectively. The GC activity was found to be lower in STa treated hamster BBM compared to that of guinea pig. Scatchard analysis of the stoichiometric data showed a linear plot, and STa bound with association constants of 0.31 x 10(12) M-1 and 1.04 x 10(12) M-1 in hamsters and guinea pigs respectively. Autoradiographic analysis of the SDS-PAGE, revealed that 125I-STa bound apparently to a 45 kDa membrane protein in hamster and a 115 kDa membrane protein in guinea pig. INTERPRETATION & CONCLUSIONS It appears that a lower density of STa receptor exists in hamsters compared to that in guinea pigs. STa binds with a single population of STa receptors in each species with different ligand binding affinities. Also, the molecular weights of the STa binding proteins differ in these species. Moreover, the GC activity was found to be lower in hamsters than in guinea pigs.
Collapse
Affiliation(s)
- J Bhattacharya
- Division of Pathophysiology, National Institute of Cholera & Enteric Diseases, Calcutta, India
| | | | | | | | | |
Collapse
|
31
|
Pal A, Hoque KM, Niyogi SK, Ramamurthy T, Nair GB, Bhattacharya SK, Chakrabarti MK. Rise in free intracellular calcium in HeLa cells infected with aggregative Klebsiella pneumoniae strains isolated from cases of diarrhoea. Indian J Med Res 2001; 113:1-4. [PMID: 11280164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
BACKGROUND & OBJECTIVES Klebsiella pneumoniae strains occasionally cause diarrhoea in humans. This study was done to determine the involvement of calcium in the pathogenesis of aggregative K. pneumoniae strains. METHODS A total of nine strains of K. pneumoniae were tested for adherence assay in HeLa cell line. A representative strain CO-1215 was used for [Ca2+]i study using Fura-2 fluorescence. RESULTS Infection of cultured HeLa cells with aggregative K. pneumoniae strain resulted in five-fold elevation of intracellular level of free calcium ([Ca2+]i) with maximum Ca2+ influx at 3 h after bacterial infection. Chelation of extracellular Ca2+ with [ethylenebis(oxyethylenenitrile)] tetraacetic acid and suspension of cells in Ca2+ free buffer suggested that the rise of Ca2+ in aggregative K. pneumoniae infected HeLa cells was due to influx of Ca2+ from extracellular medium. INTERPRETATION & CONCLUSIONS This study showed aggregative adherence in HeLa cells and this adherence leads to influx of extracellular Ca2+. The unrestricted passage of calcium ions across cell membranes could cause phosphorylation of proteins involved in ion transport across the membrane, which could result in secretory diarrhoea. Further work is in progress to study the enterotoxicity of these strains in an in vitro rabbit intestinal model.
Collapse
Affiliation(s)
- A Pal
- National Institute of Cholera & Enteric Diseases (ICMR), Calcutta, India
| | | | | | | | | | | | | |
Collapse
|
32
|
Abstract
The effects of desflurane on renal sympathetic nerve activity (RSNA) were studied in intact or vagotomized anaesthetized rabbits with initial concentrations of 4.5-18%, subsequently equilibrated to end-tidal concentrations from 3%, 6%, 9% and 12% each for 20 min allowing sympathetic activity to stabilize. In intact animals, immediate transient increases in mean sympathetic activity from 27% to 63% were closely related to initial concentrations from 4.5% to 18%. During subsequent equilibration this remained elevated by 25-30% up to 6%, returned to control at 9% and fell by 33% at 12%. Bilateral vagotomy abolished sympathoexcitation apart from small increases in sympathetic activity, for example 14% at 4.5% (P < 0.05). We conclude that increases in inspired desflurane concentrations evoked rapid transient vagally mediated reflex sympathoexcitation with a small extra-vagal contribution. Central depression of sympathetic activity started at 6% and was 33% below baseline at 12%.
Collapse
Affiliation(s)
- C K Pac-Soo
- Department of Anaesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital, London, UK
| | | | | | | | | |
Collapse
|
33
|
Pac-Soo CK, Wang C, Chakrabarti MK, Whitwam JG. Comparison of the effects of inhalational anaesthetic agents on sympathetic activity in rabbits. Eur J Anaesthesiol 2000; 17:311-8. [PMID: 10926072 DOI: 10.1046/j.1365-2346.2000.00669.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effects of inhalational anaesthetic agents on renal sympathetic nerve activity (RSNA) were compared in anaesthetized rabbits. Concentrations of 6% desflurane, 1.2% isoflurane, and 2.4% enflurane increased mean RSNA up to 32, 36 and 44% while higher concentrations, of 12, 2.4 and 3.2% depressed it by 42, 83 and 5%, respectively. For halothane RSNA was unchanged up to 0.8% and decreased by 36% at 1.6% concentration. Nitrous oxide increased RSNA up to 28% at 50% concentration. Maximum reductions in mean arterial pressure (MAP) were 60% for both 2.4% isoflurane and 3.2% enflurane, 50% for 12% desflurane and 1.6% halothane, while 70% nitrous oxide increased MAP by 22%. In conclusion, unlike the entirely depressive effects of halothane, the effects of desflurane, isoflurane and enflurane were biphasic involving excitation at lower concentrations and depression of RSNA and a reduction in MAP at higher concentrations. Nitrous oxide caused increases in both RSNA and MAP.
Collapse
Affiliation(s)
- C K Pac-Soo
- Department of Anaesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital, London, UK
| | | | | | | |
Collapse
|
34
|
Whitwam JG, Galletly DC, Ma D, Chakrabarti MK. The effects of propofol on heart rate, arterial pressure and adelta and C somatosympathetic reflexes in anaesthetized dogs. Eur J Anaesthesiol 2000; 17:57-63. [PMID: 10758446 DOI: 10.1046/j.1365-2346.2000.00605.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effects of propofol on mean arterial pressure, heart rate and Adelta and C somatosympathetic reflexes, recorded in renal nerves, evoked by repeated individual supramaximal electrical stimuli applied to radial nerves, were observed in anaesthetized, paralysed and artificially ventilated dogs. Propofol was infused at rates from 0.4 to 2.0 mg kg-1 min-1. Mean C and Adelta reflexes were abolished at plasma concentrations (mean, SEM) of 24.3 (3.3) and 29.2 (2.6) microg mL-1 (P < 0.05), respectively, when mean arterial pressure and mean heart rate were reduced by approximately 55% (P < 0.01) and 26% (P > 0.05), respectively. Recovery of Adelta and C reflexes occurred at plasma concentrations of 13.1 (2.3) and 9.9 (1.3) microg mL-1 (P > 0.05), respectively. There was a log- arithmically linearly related fall in mean arterial pressure by 70% up to a plasma concentration approximately 97 microg mL-1 (r 2=0.7) with a 28% reduction in heart rate which was uncorrelated with the plasma concentrations (r 2=0.12). In conclusion, propofol abolished Adelta and C responses at comparable plasma concentrations and caused a major reduction in both mean arterial pressure and heart rate which is consistent with resetting of the baroreflexes. The reduction in mean arterial pressure was logarithmically, linearly correlated with a progressive increase in plasma concentrations without evidence of a ceiling effect.
Collapse
Affiliation(s)
- J G Whitwam
- Department of Anaesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital, London UK
| | | | | | | |
Collapse
|
35
|
Abstract
BACKGROUND The effects of propofol, remifentanil, and their combination on phrenic nerve activity (PNA), resting heart rate (HR), mean arterial pressure (MAP), and nociceptive cardiovascular responses were studied in rabbits. METHODS Basal anesthesia and constant blood gas tensions were maintained with alpha-chloralose and mechanical ventilation. PNA, HR, MAP, and maximum changes in HR and MAP (deltaHR, deltaMAP) evoked by electrical nerve stimulation of tibial nerves were recorded. The comparative effects were observed for propofol at infusion rates from 0.05 to 3.2 mg x kg(-1) x min(-1) (group I) and remifentanil from 0.0125 to 12.8 microg x kg(-1) x min(-1) alone (group II), and during constant infusions of propofol at rates of 0.1 and 0.8 mg x kg(-1) x min(-1) (groups III and IV, respectively). Finally, the effect of remifentanil on propofol blood levels was observed (group V). RESULTS The infusion rates for 50% depression (ED50) of PNA, deltaHR, and deltaMAP were 0.41, 1.32, and 1.58 mg x kg-(1) x min(-1) for propofol, and 0.115, 0.125, and 1.090 microg x kg(-1) x min(-1) for remifentanil, respectively. The ratios for the ED50 values of deltaHR and deltaMAP to PNA were 3.2 and 3.9 for propofol, and 1.1 and 9.5 for remifentanil, respectively. Analysis of the expected and observed responses and isobologrms showed that although their combined effects on PNA, resting HR, and MAP, and deltaMAP were synergistic for deltaHR, they were merely additive. Remifentanil had no effect on propofol blood levels. CONCLUSION PNA was abolished by propofol and remifentanil, alone and in combination, before significant depression of nociceptive pressor responses occurred. Their combined effects on PNA, HR, MAP, and deltaMAP are greater than additive, ie., synergistic. Unlike propofol, remifentanil obtunded pressor responses more than the resting circulation.
Collapse
Affiliation(s)
- D Ma
- Department of Anaesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital, London, United Kingdom.
| | | | | |
Collapse
|
36
|
Basu I, Mitra R, Saha PK, Ghosh AN, Bhattacharya J, Chakrabarti MK, Takeda Y, Nair GB. Morphological and cytoskeletal changes caused by non-membrane damaging cytotoxin of Vibrio cholerae on int 407 and HeLa cells. FEMS Microbiol Lett 1999; 179:255-63. [PMID: 10518724 DOI: 10.1111/j.1574-6968.1999.tb08736.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Vibrio cholerae produces a non-membrane damaging cytotoxin (NMDCY), also known as cell rounding factor, which causes rapid rounding of cultured cells like HeLa, CHO and Vero and reportedly elicits enterotoxic activity in the rabbit ileal loop assay. Pursuing the concept that NMDCY might be an accessory factor contributing to the diarrhea caused by V. cholerae, we investigated the effect of NMDCY on Int 407 (intestinal cell line) and HeLa (non-intestinal cell line) cells using light, fluorescent and electron microscopy to gain insight into the cellular response evoked by NMDCY. Binding assays showed that NMDCY has affinity for both Int 407 and HeLa cells. Changes in the internal organelles and cytoskeletal structures of the cell lines were documented indicating changes in the secretory and metabolic function of the toxin-treated cells. Toxin-treated cells visualized under the electron microscope revealed retraction of cell body, formation of blebs on cell surface, changes in mitochondria having dilated and rarefied matrix and an extensively developed Golgi apparatus, endoplasmic reticulum and lysosomes compared to those in normal cells. Immunofluorescence study showed restructuring of microfilament network represented by actin, filamin and vinculin, as also of the microtubular component, tubulin and the intermediate filament, vimentin. Immunogold study further revealed that the toxin is internalized even within the nucleus. Moreover, a rise in the intracellular calcium level of the NMDCY-treated cells leads us to hypothesize that a cascade of events results in the final impairment of the cell machinery.
Collapse
Affiliation(s)
- I Basu
- National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme XM, Beliaghata, Calcutta, India
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Ma D, Chakrabarti MK, Whitwam JG. The combined effects of sevoflurane and remifentanil on central respiratory activity and nociceptive cardiovascular responses in anesthetized rabbits. Anesth Analg 1999; 89:453-61. [PMID: 10439766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
UNLABELLED We studied the effects of sevoflurane and remifentanil, alone and in combination, on phrenic nerve activity (PNA), resting heart rate (HR), arterial pressure (MAP), and changes in HR (delta HR) and MAP (delta MAP) evoked by electrical stimulation of tibial nerves in anesthetized rabbits. The 50% effective dose (95% confidence intervals) for the depressant effects of sevoflurane on delta HR, delta MAP, and PNA were 2.3 (1.8%-2.6%), 2.7 (2.3%-2.9%), and 3.4 (3.1%-3.7%), respectively, and for remifentanil were 0.100 (0.050-0.132), 0.850 (0.720-1.450), and 0.090 (0.080-0.145) microgram.kg-1.min-1, which were reduced to 0.046 (0.021-0.065), 0.110 (0.080-0.200), and 0.030 (0.020-0.040) microgram.kg-1.min-1, respectively, by 1% sevoflurane. Depression of evoked cardiovascular responses relative to PNA was greater for sevoflurane and less for remifentanil both alone and in combination with sevoflurane. Sevoflurane acted synergistically with remifentanil on PNA and delta MAP, but not delta HR, for which their combined effect was additive. Coadministration of 1% sevoflurane with the highest infusion rate of remifentanil (1.6 micrograms.kg-1.min-1) used during combined administration reduced resting HR and MAP by 25% (P < 0.05) and 41% (P < 0.05), respectively, which was greater than the predicted reductions of only 14% and 15% if their combined effects had been additive. We conclude that sevoflurane caused a relatively greater depression of nociceptive cardioaccelerator and pressor responses compared with PNA and vice versa for remifentanil. When coadministered, their combined effects on PNA, resting HR, MAP, and delta MAP were synergistic, whereas they were merely additive for delta HR. IMPLICATIONS Although sevoflurane caused relatively greater depression of nociceptive cardiovascular responses compared with phrenic nerve activity, remifentanil either alone or combined with sevoflurane caused a much greater depression of phrenic nerve activity than cardio-accelerator and pressor responses. This could imply that, during major surgery using anesthesia combining sevoflurane and remifentanil, spontaneous ventilation is not acceptable, and depression of the resting circulation may be much greater than anticipated.
Collapse
Affiliation(s)
- D Ma
- Department of Anaesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital, London, United Kingdom.
| | | | | |
Collapse
|
38
|
Pac-Soo CK, Ma D, Wang C, Chakrabarti MK, Whitwam JG. Specific actions of halothane, isoflurane, and desflurane on sympathetic activity and A delta and C somatosympathetic reflexes recorded in renal nerves in dogs. Anesthesiology 1999; 91:470-8. [PMID: 10443611 DOI: 10.1097/00000542-199908000-00022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND This was a study of the relative effects on directly recorded sympathetic activity of desflurane, isoflurane, and halothane. METHODS Renal sympathetic nerve activity (RSNA) was recorded with bipolar electrodes in renal nerves exposed retroperitoneally in anesthetized (alpha-chloralose), paralyzed (succinylcholine), and artificially ventilated dogs. Somatosympathetic responses were evoked by supramaximal electrical stimulation of radial nerves (0.33 Hz, 30 V, 0.5 ms). Spontaneous and evoked activity were rectified, averaged, and integrated to allow quantitative comparison of the effects of 3-12% desflurane, 0.6-2.4% isoflurane, and 0.4-1.6% halothane. RESULTS Increasing concentrations of isoflurane progressively depressed mean RSNA, Adelta, and C reflexes by 40% (P < 0.01), 50% (P < 0.01) and 70% (P < 0.001) respectively at 2.4% concentration. Halothane depressed both reflexes equally by approximately 60% (P < 0.01) at 1.6% concentration, without significant depression of spontaneous RSNA. Desflurane increased and subsequently decreased RSNA by 37% (P < 0.02) and 65% (P < 0.001) at concentrations of 6% and 12% respectively, and although somatosympathetic reflexes remained unchanged up to 9%, both were depressed equally by 70% (P < 0.01) at 12% concentration. CONCLUSION After equilibration, lower concentrations of desflurane remained excitatory, but, like isoflurane, higher concentrations depressed RSNA. The effect of halothane on RSNA was insignificant. Isoflurane depressed C more than Adelta somatosympathetic reflexes, which is uncorrelated with lipid solubility because desflurane and halothane, which have the highest and lowest minimum alveolar concentration, respectively, depressed both equally.
Collapse
Affiliation(s)
- C K Pac-Soo
- Department of Anesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital, London, United Kingdom.
| | | | | | | | | |
Collapse
|
39
|
Abstract
Propofol may cause profound bradycardia and asystole, which are mediated indirectly via cardiac innervation but could involve direct effects on the sino-atrial (SA) node and the conducting system of the heart. To test the hypothesis that propofol may also activate Bezold-Jarisch reflexes to cause bradycardia, 5-hydroxytryptamine (5-HT), veratridine and propofol were injected into the left ventricle of the heart in both intact and vagotomized rabbits. 5-HT and veratridine produced an acute, rapid, dose-dependent decrease in mean heart rate (delta HR) and a decrease in mean arterial pressure (delta MAP) together with transient but severe depression and abolition of renal sympathetic nerve activity (RSNA). Bilateral vagotomy greatly attenuated these responses; for example, at the highest dose of 5-HT (8 micrograms kg-1), delta HR, delta MAP and duration of abolition of RSNA were reduced by 57% (P < 0.001), 53% (P < 0.05) and 79% (P < 0.05), respectively. In contrast, reductions in delta HR and delta MAP produced by propofol were statistically significant only at very high doses (8 mg kg-1). Propofol depressed but did not abolish RSNA, and bilateral vagotomy had no effect on any of these responses. These results indicate that the cause of acute bradycardia after administration of propofol does not involve the Bezold-Jarisch reflex.
Collapse
Affiliation(s)
- D Ma
- Department of Anaesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital, London, UK
| | | | | |
Collapse
|
40
|
Bhattacharya J, Chakrabarti MK. Binding of Escherichia coli heat-stable toxin and rise of guanylyl cyclase activity in the brush-border membranes of rabbit intestinal epithelial cells. J Diarrhoeal Dis Res 1999; 17:28-33. [PMID: 10892494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The study examines the age-related differences in the density of Escherichia coli heat-stable enterotoxin (STa) receptors in the small intestine of rabbits. The number of STa receptors was found to be 1.7 x 10(12) in 14-day old rabbits compared to 2.4 x 10(9) in 14-week old rabbits per milligram brush-border membrane protein. The STa-induced guanylyl cyclase activity in the intestinal brush-border membranes was found to be stimulated by 6.2 folds over the basal enzyme activity in 14-day old rabbits, whereas in the 14-week old rabbits, it was 4 folds over the basal activity. Moreover, the enzyme activity remained lower in the adult rabbits compared to the younger ones. Autoradiographic analysis of sodium dodecyl sulphate polyacrylamide gel electrophoresis showed two STa-binding proteins of apparent molecular weights of 140 and 38 kDa in the intestinal brush-border membranes of rabbits.
Collapse
Affiliation(s)
- J Bhattacharya
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Beliaghata, Calcutta, India
| | | |
Collapse
|
41
|
Chakrabarti MK, Bhattacharya J, Bhattacharya MK, Nair GB, Bhattacharya SK, Mahalanabis D. Killed oral Shigella vaccine made from Shigella flexneri 2a protects against challenge in the rabbit model of shigellosis. Acta Paediatr 1999; 88:161-5. [PMID: 10102148 DOI: 10.1080/08035259950170321] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
Abstract
The protective efficacy of an orally administered heat-killed virulent strain of Shigella flexneri 2a (5 weekly oral doses) was evaluated in 25 rabbits (14 immunized and 11 non-immunized controls) against challenge with the same strain of Shigella using the rabbit model of shigellosis. All 11 non-immunized rabbits developed bloody diarrhoea following challenge and 6 (54%) died. None of the 14 immunized rabbits developed diarrhoea (all had pellet stools) but 3 (21%) died from causes not associated with diarrhoea. Protection from diarrhoea and dysentery following oral immunization with a killed Shigella species was 100% and highly significant. Death following challenge was 2.5-fold higher in the non-immunized group (p = 0.115) but was not significant. These promising results suggest that further studies should be undertaken to develop a killed oral vaccine against shigellosis.
Collapse
Affiliation(s)
- M K Chakrabarti
- Society for Applied Studies and National Institute of Cholera, Calcutta, India
| | | | | | | | | | | |
Collapse
|
42
|
Ma D, Sapsed-Byrne SM, Chakrabarti MK, Ridout D, Whitwam JG. Synergism between sevoflurane and intravenous fentanyl on A delta and C somatosympathetic reflexes in dogs. Anesth Analg 1998; 87:211-6. [PMID: 9661576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
UNLABELLED In this study, we defined the nature of the interactions between sevoflurane and fentanyl on spontaneous and reflex-evoked sympathetic activity, resting heart rate (HR), and mean arterial pressure (MAP). Spontaneous renal sympathetic nerve activity (RSNA) and A delta- and C-fiber-mediated somatosympathetic reflexes, evoked by electrical stimulation of radial nerves, and HR and MAP were recorded in anesthetized dogs. In one group, the effects of incremental doses of 2-64 micrograms/kg fentanyl i.v. were observed. It had a greater inhibitory effect on C than on A delta reflexes, which were abolished by mean cumulative doses of 64 micrograms/kg and approximately 128 micrograms/kg, respectively. Although 1.5% sevoflurane reduced C reflexes by 28% and A delta reflexes by only 12%, it reduced the total doses of fentanyl required for their abolition to 32 micrograms/kg and 64 micrograms/kg, respectively. Mean RSNA, HR, and MAP values were reduced by 46%, 54%, and 30%, respectively, by fentanyl alone and by 23%, 11%, and 17%, respectively, in response to 1.5% sevoflurane. The combination of fentanyl and sevoflurane caused reductions of 44%, 54%, and 41%, respectively, which indicates a less than additive effect. These results indicate that sevoflurane interacts synergistically with fentanyl to depress A delta and C somatosympathetic reflexes, whereas for RSNA, HR, and MAP, their effects were less than the additive. IMPLICATIONS Although fentanyl caused a greater depression of C than of A delta reflexes to the point of abolition, the maximal depression of spontaneous sympathetic activity, heart rate, and arterial pressure occurred at smaller doses. The combined depressant effects of sevoflurane and fentanyl were synergistic on somatosympathetic reflexes but were less than additive on spontaneous sympathetic activity, heart rate, and arterial pressure.
Collapse
Affiliation(s)
- D Ma
- Department of Anaesthetics, Imperial College School of Medicine, Hammersmith Hospital, London, United Kingdom.
| | | | | | | | | |
Collapse
|
43
|
Ma D, Sapsed-Byrne SM, Chakrabarti MK, Whitwam JG. Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits. Acta Anaesthesiol Scand 1998; 42:670-7. [PMID: 9689273 DOI: 10.1111/j.1399-6576.1998.tb05300.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e.g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. METHODS PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 microgram.kg-1 i.v. or midazolam 0.05 mg.kg-1 i.v. on the effects of propofol and fentanyl respectively on PNA were studied. RESULTS Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg.kg-1 i.v. and 32 micrograms.kg-1 i.v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg.kg-1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg.kg-1. The mean ED50s, calculated from dose-response curves, were 5.4 mg.kg-1, 3.9 micrograms.kg-1 and 0.4 mg.kg-1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 microgram.kg-1 i.v. or midazolam 0.05 mg.kg-1 i.v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg.kg-1 and 8 micrograms.kg-1, respectively. CONCLUSION Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.
Collapse
Affiliation(s)
- D Ma
- Department of Anaesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital London, UK
| | | | | | | |
Collapse
|
44
|
Ma D, Sapsed-Byrne SM, Chakrabarti MK, Whitwam JG. Synergistic antinociceptive interaction between sevoflurane and intrathecal fentanyl in dogs. Br J Anaesth 1998; 80:800-6. [PMID: 9771311 DOI: 10.1093/bja/80.6.800] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This study determined the nature of the antinociceptive interaction between sevoflurane and intrathecal fentanyl on somatosympathetic reflexes in anaesthetized dogs. Afferent A delta- and C-fibre-mediated somatosympathetic reflexes, evoked by supramaximal electrical stimulation of tibial nerves, were recorded from renal sympathetic nerves. The effect of fentanyl alone, administered intrathecally (i.t.) in incremental doses from 2 to 64 micrograms, was compared with the effect of the same doses during the administration of 1.5% sevoflurane. The mean ED50s for the depressant effect of fentanyl (i.t.) on A delta and C reflexes were 35.6 micrograms and 14.2 micrograms while 1.5% sevoflurane, when administered alone, depressed them by 15.5% (P < 0.05) and 27.5% (P < 0.01) respectively. During the administration of 1.5% sevoflurane, the mean ED50s of fentanyl (i.t.) for the depression of A delta and C reflexes were reduced by 76% and 75%, to 8.5 micrograms and 3.5 micrograms respectively. The combined antinociceptive effects of sevoflurane and intrathecal fentanyl were not additive but exhibited a high degree of synergistic interaction.
Collapse
Affiliation(s)
- D Ma
- Department of Anaesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital, London
| | | | | | | |
Collapse
|
45
|
Bhattacharya J, Chakrabarti MK. Rise of intracellular free calcium levels with activation of inositol triphosphate in a human colonic carcinoma cell line (COLO 205) by heat-stable enterotoxin of Escherichia coli. Biochim Biophys Acta 1998; 1403:1-4. [PMID: 9622581 DOI: 10.1016/s0167-4889(98)00026-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The heat-stable enterotoxin (STa) produced by Escherichia coli has been found to increase rapidly two potential intracellular signals, inositol triphosphate and cytosolic free calcium in a human colonic cell line, COLO 205. Addition of STa to COLO 205 cells prelabelled with myo-[2-3H]inositol resulted in a rapid rise of [3H]inositol triphosphate. Using fluorescent indicator, Fura-2AM, intracellular free Ca2+ has been found to increase 5.12-fold compared to control. Suspension of cells in calcium-free buffer demonstrated STa-induced rapid rise of cytosolic Ca2+. The same result was found when extracellular calcium was chelated with EGTA. This effect was not observed with cells that were pretreated with dantrolene which suggest that the intracellular calcium rise might be due to mobilization from intracellular stores. This study demonstrated for the first time a change in cytosolic calcium in cultured human colonic cells by STa, which is accompanied by inositol triphosphate activation.
Collapse
Affiliation(s)
- J Bhattacharya
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Calcutta 700 010, India
| | | |
Collapse
|
46
|
Ma D, Wang C, Pac Soo CK, Chakrabarti MK, Lockwood GG, Whitwam JG. The effect of sevoflurane on spontaneous sympathetic activity, A delta and C somatosympathetic reflexes, and associated hemodynamic changes in dogs. Anesth Analg 1998; 86:1079-83. [PMID: 9585302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
UNLABELLED This study examined the effect of sevoflurane on spontaneous renal sympathetic nerve activity (RSNA), A delta- and C-fiber-mediated somatosympathetic reflexes, and hemodynamic changes in anesthetized dogs. RSNA, and A delta and C reflexes evoked by electrical stimulation of the radial nerve were observed in multifiber recordings of efferent activity in renal sympathetic nerves. Sevoflurane was administered at 1%, 2%, 3%, and 4% end-tidal concentrations for periods of 20 min. The mean A delta reflexes decreased by 20%, 39%, and 54% (P < 0.05 to < 0.01), and the C reflexes decreased by 38%, 62%, and 74% (P < 0.05 to < 0.01) at concentrations of 2%, 3%, and 4%, respectively. The relatively greater effect on C reflexes was significant (P < 0.05) and comparable with the effect of mu-opioids. There was no change in mean RSNA, heart rate (HR), and cardiac output (CO) up to 3% sevoflurane, but these decreased by 36%, 24%, and 13% (P < 0.05), respectively, at 4% sevoflurane. Sevoflurane 1%-4% caused a virtually linear reduction in systemic vascular resistance (SVR) from 7% (P < 0.05) to 44% (P < 0.05), together with a reduction in mean arterial pressure (MAP) that was significant for concentrations greater than 2%. The results indicate that sevoflurane causes a greater depression of C compared with A delta reflexes, and that the reduction in MAP was entirely due to a decrease in SVR up to 3%, whereas at 4% sevoflurane, reductions in sympathetic activity, HR, and CO also contributed its depressor effect. IMPLICATIONS The relatively greater depressant effect of sevoflurane on C compared with A delta nociceptive somatosympathetic reflexes is similar to mu-opioids. The hypotensive effect of sevoflurane was significant at 2% concentration, whereas heart rate, cardiac output and sympathetic activity were reduced only at concentrations greater than 3%.
Collapse
Affiliation(s)
- D Ma
- Department of Anaesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital, London, England.
| | | | | | | | | | | |
Collapse
|
47
|
Chakrabarti MK, Bhattacharya MK, Bhattacharya J, Bhattacharya SK, Mahalanabis D. Evaluation of different antibiotics in inhibiting colonization of Vibrio cholerae O1 and O139 in the rabbit intestine. Chemotherapy 1998; 44:108-11. [PMID: 9551241 DOI: 10.1159/000007101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The effects of furazolidone, erythromycin and azithromycin in inhibiting colonisation of Vibrio cholerae O1 and O139 in the rabbit intestine were tested. Both V. cholerae O1 and O139 highly colonised the gut in control rabbits. The colonisation of furazolidone-resistant strains in the rabbit intestine was prevented effectively by both erythromycin and azithromycin. In furazolidone-sensitive strains, the efficacies of erythromycin and azithromycin were very much comparable to furazolidone. These results suggested that azithromycin may be subjected to clinical trial in comparison to furazolidone and erythromycin for the treatment of cholera due to O1 and O139 infection in children.
Collapse
Affiliation(s)
- M K Chakrabarti
- National Institute of Cholera and Enteric Diseases, Calcutta, India.
| | | | | | | | | |
Collapse
|
48
|
Chaudhuri AG, Bhattacharya J, Nair GB, Takeda T, Chakrabarti MK. Rise of cytosolic Ca2+ and activation of membrane-bound guanylyl cyclase activity in rat enterocytes by heat-stable enterotoxin of Vibrio cholerae non-01. FEMS Microbiol Lett 1998; 160:125-9. [PMID: 9495023 DOI: 10.1111/j.1574-6968.1998.tb12901.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The cytosolic calcium level ([Ca2+]i) and the membrane-bound guanylyl cyclase activity in the isolated rat intestinal epithelial cells were investigated. Heat-stable enterotoxin of Vibrio cholerae non-01 (NAG-ST) was found to increase both the [Ca2+]i and the enzyme activity. These changes occur similarly until 5 min of incubation with NAG-ST, indicating that these changes might be involved in NAG-ST induced signal transduction in rat enterocytes.
Collapse
Affiliation(s)
- A G Chaudhuri
- National Institute of Cholera and Enteric Diseases, Beliaghata, Calcutta, India
| | | | | | | | | |
Collapse
|
49
|
Abstract
Sevoflurane causes a decrease in mean arterial pressure (MAP). We have studied in anaesthetized rabbits its interactive effects on MAP, the autonomic nervous system and baroreflexes. During sevoflurane administration changes in renal sympathetic nerve activity (RSNA) and heart rate (HR) were observed: (1) when the normal decrease in MAP occurred; (2) when this was prevented by angiotensin II; (3) during a similar decrease in MAP induced by infusion of sodium nitroprusside (SNP) without sevoflurane administration; and (4) during pressor and depressor responses to phenylephrine and SNP. There was a reduction in MAP from 80 to 40 mm Hg after 1-4% sevoflurane without changes in HR, while RSNA remained unchanged only up to concentrations of 3% and was depressed by 37% (P < 0.05) with 4% sevoflurane. When MAP was maintained constant with angiotensin II, both HR and RSNA decreased, by 12% and 69%, respectively, after 4% sevoflurane (P < 0.05). A decrease in MAP of 40 mm Hg during infusion of SNP increased HR and RSNA by 22% (P < 0.05) and 150% (P < 0.01), respectively. At 2% sevoflurane, baroreflex sensitivity (i.e. delta RSNA/delta MAP and delta HR/delta MAP) was depressed by 36% and 57%, respectively, for the pressor effects of pherylephrine, and by 89% and 81%, respectively, for the depressor effects of SNP. We conclude that the baroreflexes continued to compensate for the effects of sevoflurane on sympathetic and cardiomotor activity with concentrations up to 3% and 4%, respectively.
Collapse
Affiliation(s)
- D Ma
- Department of Anaesthesia, Royal Postgraduate Medical School, Hammersmith Hospital, London
| | | | | | | |
Collapse
|
50
|
Bhattacharya J, Chaudhuri AG, Sinha AK, Samanta AK, Chakrabarti MK. Binding of Escherichia coli heat-stable enterotoxin and rise of cyclic GMP in COLO 205 human colonic carcinoma cells. FEMS Microbiol Lett 1997; 156:79-83. [PMID: 9368363 DOI: 10.1111/j.1574-6968.1997.tb12708.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Escherichia coli heat-stable enterotoxin (STa) was found to bind on the surface of human colonic (COLO 205) cells. The binding of [125I]STa to cell membranes was found to be specific, reversible and saturable. Scatchard analysis of the equilibrium binding demonstrated a single class of binding sites with a Kd of 0.5 x 10(-10) M. Autoradiographic analysis of polyacrylamide gel electrophoresis revealed the specific incorporation of [125I]STa into a single STa binding protein with a molecular mass of 95 kDa. Following incubation of COLO 205 cells with STa, a rise of intracellular cGMP was also evident.
Collapse
Affiliation(s)
- J Bhattacharya
- Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Calcutta, India
| | | | | | | | | |
Collapse
|