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Norman KM, Lang GA, Shadid TM, Honold ST, Reel JM, Cox MA, Ballard JD, Lang ML. Clostridioides difficile toxin B subverts germinal center and antibody recall responses by stimulating a drug-treatable CXCR4-dependent mechanism. Cell Rep 2024; 43:114245. [PMID: 38761377 PMCID: PMC11210377 DOI: 10.1016/j.celrep.2024.114245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 04/04/2024] [Accepted: 05/02/2024] [Indexed: 05/20/2024] Open
Abstract
Recurrent Clostridioides difficile infection (CDI) results in significant morbidity and mortality. We previously established that CDI in mice does not protect against reinfection and is associated with poor pathogen-specific B cell memory (Bmem), recapitulating our observations with human Bmem. Here, we demonstrate that the secreted toxin TcdB2 is responsible for subversion of Bmem responses. TcdB2 from an endemic C. difficile strain delayed immunoglobulin G (IgG) class switch following vaccination, attenuated IgG recall to a vaccine booster, and prevented germinal center formation. The mechanism of TcdB2 action included increased B cell CXCR4 expression and responsiveness to its ligand CXCL12, accounting for altered cell migration and a failure of germinal center-dependent Bmem. These results were reproduced in a C. difficile infection model, and a US Food and Drug Administration (FDA)-approved CXCR4-blocking drug rescued germinal center formation. We therefore provide mechanistic insights into C. difficile-associated pathogenesis and illuminate a target for clinical intervention to limit recurrent disease.
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Affiliation(s)
- Kaylee M Norman
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Gillian A Lang
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Tyler M Shadid
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Sydney T Honold
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Jessica M Reel
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Maureen A Cox
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Jimmy D Ballard
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Mark L Lang
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA.
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Fettucciari K, Dini F, Marconi P, Bassotti G. Role of the Alteration in Calcium Homeostasis in Cell Death Induced by Clostridioides difficile Toxin A and Toxin B. BIOLOGY 2023; 12:1117. [PMID: 37627001 PMCID: PMC10452684 DOI: 10.3390/biology12081117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 08/05/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023]
Abstract
Clostridioides difficile (C. difficile), responsible for 15-25% of gastrointestinal infections, causes health problems mainly due to the toxic activity of toxins A and B (Tcds). These are responsible for its clinical manifestations, including diarrhea, pseudomembranous colitis, toxic megacolon and death, with a mortality of 5-30% in primary infection, that increase following relapses. Studies on Tcd-induced cell death have highlighted a key role of caspases, calpains, and cathepsins, with involvement of mitochondria and reactive oxygen species (ROS) in a complex signaling pathway network. The complex response in the execution of various types of cell death (apoptosis, necrosis, pyroptosis and pyknosis) depends on the amount of Tcd, cell types, and Tcd receptors involved, and could have as initial/precocious event the alterations in calcium homeostasis. The entities, peculiarities and cell types involved in these alterations will decide the signaling pathways activated and cell death type. Calcium homeostasis alterations can be caused by calcium influx through calcium channel activation, transient intracellular calcium oscillations, and leakage of calcium from intracellular stores. These increases in cytoplasmic calcium have important effects on all calcium-regulated molecules, which may play a direct role in several cell death types and/or activate other cell death effectors, such as caspases, calpains, ROS and proapoptotic Bcl-2 family members. Furthermore, some support for the possible role of the calcium homeostasis alteration in Tcd-induced cell death originates from the similarity with cytotoxic effects that cause pore-forming toxins, based mainly on calcium influx through plasma membrane pores.
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Affiliation(s)
- Katia Fettucciari
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy;
| | - Fabrizio Dini
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024 Matelica, Italy;
| | - Pierfrancesco Marconi
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy;
| | - Gabrio Bassotti
- Gastroenterology, Hepatology & Digestive Endoscopy Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy;
- Gastroenterology & Hepatology Unit, Santa Maria Della Misericordia Hospital, 06129 Perugia, Italy
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Paudice M, Biatta CM, Scaglione G, Parodi A, Mammoliti S, Moioli M, Centurioni MG, Barra F, Ferrero S, De Cian F, Mazzocco K, Vellone VG. Histopathological and Immunohistochemical Prognostic Factors in High-Grade Non-Endometrioid Carcinomas of the Endometrium (HG-NECs): Is It Possible to Identify Subgroups at Increased Risk? Diagnostics (Basel) 2023; 13:2171. [PMID: 37443564 DOI: 10.3390/diagnostics13132171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/07/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Endometrial cancer is an emerging disease with an increase in prevalence of aggressive histotypes in recent years. BACKGROUND In the present study, potential histopathological and immunohistochemical prognostic markers were investigated. Consecutive cases of high-grade non-endometrioid carcinoma (HG-NEC) of the endometrium were considered. METHODS Each surgical specimen was routinely processed; the most significant block was selected for immunohistochemistry and tested for ER, PR, ki67, p53, E-cadherin, β-catenin, Bcl-2 and cyclin D1. For each immunomarker, the percentage of positive tumor cells was evaluated (%) and dichotomized as low and high according to the distribution in the study population. Follow-up was collected for disease-free survival (DFS) and overall survival (OS). Thirty-three cases were eligible: 19 resulted in FIGO I-II; 14 resulted in FIGO III-IV. Twelve patients suffered a recurrent disease (mean follow-up 24.6 months); 8 patients died of the disease (mean follow-up 26.6 months). RESULTS Women with recurrent disease demonstrated a significantly higher Bcl2% (35.84 ± 30.96% vs. 8.09 ± 11.56%; p = 0.0032) while DOD patients had higher ki67% (75 ± 13.09% vs. 58.6 ± 19.97%; p = 0.033) and Bcl2% of border significance (34.37 ± 34.99% vs. 13 ± 17.97%; p = 0.078). As expected, FIGO III-IV had a worse DFS (HR = 3.34; 95% CI: 1.1-10.99; p = 0.034) and OS (HR = 5.19; 95% CI: 1.27-21.14; p = 0.0217). Bcl-2-high patients (Bcl2 > 10%) demonstrated a significantly worse DFS (HR = 9.11; 95% CI: 2.6-32.4; p = 0.0006) and OS (HR = 7.63; 95% CI: 1.7-34; p = 0.0084); moreover, PR low patients (PR ≤ 10%) had significantly worse DFS (HR = 3.74; 95% CI: 1.2-11.9; p = 0.02). CONCLUSIONS HG-NEC represents a heterogeneous group of endometrial aggressive neoplasms with a worrisome prognosis, often at an advanced stage at presentation. Bcl-2 and PR may represent promising markers to identify a subgroup of patients having an even worse prognosis requiring a careful and close follow-up.
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Affiliation(s)
- Michele Paudice
- Department of Integrated Diagnostic and Surgical Sciences (DISC), University of Genoa, 16100 Genoa, Italy
- Pathology University Unit, IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Chiara Maria Biatta
- Anatomy and Pathological Histology, Veneto Institute of Oncology IOV-IRCCS, 35128 Padua, Italy
| | - Giulia Scaglione
- Pathology Unit, Fondazione Policlinico A. Gemelli IRCCS, 00168 Rome, Italy
| | - Alessia Parodi
- Department of Integrated Diagnostic and Surgical Sciences (DISC), University of Genoa, 16100 Genoa, Italy
| | - Serafina Mammoliti
- Oncology Unit 1, IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Melita Moioli
- Obstetrics & Gynecology University Unit, IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | | | - Fabio Barra
- Department of Health Sciences (DISSAL), University of Genoa, 16132 Genoa, Italy
| | - Simone Ferrero
- Obstetrics & Gynecology University Unit, IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, 16132 Genoa, Italy
| | - Franco De Cian
- Department of Integrated Diagnostic and Surgical Sciences (DISC), University of Genoa, 16100 Genoa, Italy
- General Surgery University Unit, IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Katia Mazzocco
- Pathology Unit, IRCCS Istituto Giannina Gaslini, 16132 Genoa, Italy
| | - Valerio Gaetano Vellone
- Department of Integrated Diagnostic and Surgical Sciences (DISC), University of Genoa, 16100 Genoa, Italy
- Pathology Unit, IRCCS Istituto Giannina Gaslini, 16132 Genoa, Italy
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Kwon JE, Jo SH, Song WS, Lee JS, Jeon HJ, Park JH, Kim YR, Baek JH, Kim MG, Kwon SY, Kim JS, Yang YH, Kim YG. Investigation of metabolic crosstalk between host and pathogenic Clostridioides difficile via multiomics approaches. Front Bioeng Biotechnol 2022; 10:971739. [PMID: 36118584 PMCID: PMC9478559 DOI: 10.3389/fbioe.2022.971739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 08/11/2022] [Indexed: 11/23/2022] Open
Abstract
Clostridioides difficile is a gram-positive anaerobic bacterium that causes antibiotic-associated infections in the gut. C. difficile infection develops in the intestine of a host with an imbalance of the intestinal microbiota and, in severe cases, can lead to toxic megacolon, intestinal perforation, and even death. Despite its severity and importance, however, the lack of a model to understand host-pathogen interactions and the lack of research results on host cell effects and response mechanisms under C. difficile infection remain limited. Here, we developed an in vitro anaerobic-aerobic C. difficile infection model that enables direct interaction between human gut epithelial cells and C. difficile through the Mimetic Intestinal Host–Microbe Interaction Coculture System. Additionally, an integrative multiomics approach was applied to investigate the biological changes and response mechanisms of host cells caused by C. difficile in the early stage of infection. The C. difficile infection model was validated through the induction of disaggregation of the actin filaments and disruption of the intestinal epithelial barrier as the toxin-mediated phenotypes following infection progression. In addition, an upregulation of stress-induced chaperones and an increase in the ubiquitin proteasomal pathway were identified in response to protein stress that occurred in the early stage of infection, and downregulation of proteins contained in the electron transfer chain and ATP synthase was observed. It has been demonstrated that host cell energy metabolism is inhibited through the glycolysis of Caco-2 cells and the reduction of metabolites belonging to the TCA cycle. Taken together, our C. difficile infection model suggests a new biological response pathway in the host cell induced by C. difficile during the early stage of infection at the molecular level under anaerobic-aerobic conditions. Therefore, this study has the potential to be applied to the development of future therapeutics through basic metabolic studies of C. difficile infection.
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Affiliation(s)
- Ji-Eun Kwon
- Department of Chemical Engineering, Soongsil University, Seoul, South Korea
| | - Sung-Hyun Jo
- Department of Chemical Engineering, Soongsil University, Seoul, South Korea
| | - Won-Suk Song
- Department of Chemical Engineering, Soongsil University, Seoul, South Korea
| | - Jae-Seung Lee
- Department of Chemical Engineering, Soongsil University, Seoul, South Korea
| | - Hyo-Jin Jeon
- Department of Chemical Engineering, Soongsil University, Seoul, South Korea
| | - Ji-Hyeon Park
- Department of Chemical Engineering, Soongsil University, Seoul, South Korea
| | - Ye-Rim Kim
- Department of Chemical Engineering, Soongsil University, Seoul, South Korea
| | - Ji-Hyun Baek
- Department of Chemical Engineering, Soongsil University, Seoul, South Korea
| | - Min-Gyu Kim
- Department of Chemical Engineering, Soongsil University, Seoul, South Korea
| | - Seo-Young Kwon
- Department of Chemical Engineering, Soongsil University, Seoul, South Korea
| | - Jae-Seok Kim
- Department of Laboratory Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, South Korea
| | - Yung-Hun Yang
- Department of Biological Engineering, Konkuk University, Seoul, South Korea
| | - Yun-Gon Kim
- Department of Chemical Engineering, Soongsil University, Seoul, South Korea
- *Correspondence: Yun-Gon Kim,
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Clostridioides difficile toxin B alone and with pro-inflammatory cytokines induces apoptosis in enteric glial cells by activating three different signalling pathways mediated by caspases, calpains and cathepsin B. Cell Mol Life Sci 2022; 79:442. [PMID: 35864342 PMCID: PMC9304068 DOI: 10.1007/s00018-022-04459-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 06/22/2022] [Accepted: 06/29/2022] [Indexed: 11/03/2022]
Abstract
Clostridioides difficile infection (CDI) causes nosocomial/antibiotic-associated gastrointestinal diseases with dramatically increasing global incidence and mortality rates. The main C. difficile virulence factors, toxins A and B (TcdA/TcdB), cause cytopathic/cytotoxic effects and inflammation. We demonstrated that TcdB induces caspase-dependent, mitochondria-independent enteric glial cell (EGC) apoptosis that is enhanced by the pro-inflammatory cytokines TNF-α and IFN-γ (CKs) by increasing caspase-3/7/9 and PARP activation. Because this cytotoxic synergism is important for CDI pathogenesis, we investigated the apoptotic pathways involved in TcdB- and TcdB + CK-induced apoptosis indepth. EGCs were pre-treated with the inhibitors BAF or Q-VD-OPh (pan-caspase), Z-DEVD-fmk (caspase-3/7), Z-IETD-fmk (caspase-8), PD150606 (calpains), and CA-074Me (cathepsin B) 1 h before TcdB exposure, while CKs were given 1.5 h after TcdB exposure, and assays were performed at 24 h. TcdB and TcdB + CKs induced apoptosis through three signalling pathways activated by calpains, caspases and cathepsins, which all are involved both in induction and execution apoptotic signalling under both conditions but to different degrees in TcdB and TcdB + CKs especially as regards to signal transduction mediated by these proteases towards downstream effects (apoptosis). Calpain activation by Ca2+ influx is the first pro-apoptotic event in TcdB- and TcdB + CK-induced EGC apoptosis and causes caspase-3, caspase-7 and PARP activation. PARP is also directly activated by calpains which are responsible of about 75% of apoptosis in TcdB and 62% in TcdB + CK which is both effector caspase-dependent and -independent. Initiator caspase-8 activation mediated by TcdB contributes to caspase-3/caspase-7 and PARP activation and is responsible of about 28% of apoptosis in both conditions. Caspase-3/caspase-7 activation is weakly responsible of apoptosis, indeed we found that it mediates 27% of apoptosis only in TcdB. Cathepsin B contributes to triggering pro-apoptotic signal and is responsible in both conditions of about 35% of apoptosis by a caspase-independent manner, and seems to regulate the caspase-3 and caspase-7 cleaved fragment levels, highlighting the complex interaction between these cysteine protease families activated during TcdB-induced apoptosis. Further a relevant difference between TcdB- and TcdB + CK-induced apoptosis is that TcdB-induced apoptosis increased slowly reaching at 72 h the value of 18.7%, while TcdB + CK-induced apoptosis increased strongly reaching at 72 h the value of 60.6%. Apoptotic signalling activation by TcdB + CKs is enriched by TNF-α-induced NF-κB signalling, inhibition of JNK activation and activation of AKT. In conclusion, the ability of C. difficile to activate three apoptotic pathways represents an important strategy to overcome resistance against its cytotoxic activity.
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CeO2-Zn Nanocomposite Induced Superoxide, Autophagy and a Non-Apoptotic Mode of Cell Death in Human Umbilical-Vein-Derived Endothelial (HUVE) Cells. TOXICS 2022; 10:toxics10050250. [PMID: 35622663 PMCID: PMC9147432 DOI: 10.3390/toxics10050250] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 02/01/2023]
Abstract
In this study, a nanocomposite of cerium oxide-zinc (CeO2-Zn; 26 ± 11 nm) based on the antioxidant rare-earth cerium oxide (CeO2) nanoparticles (NPs) with the modifier zinc (Zn) was synthesized by sintering method and characterized. Its bio-response was examined in human umbilical-vein-derived endothelial (HUVE) cells to get insight into the components of vascular system. While NPs of CeO2 did not significantly alter cell viability up to a concentration of 200 µg/mL for a 24 h exposure, 154 ± 6 µg/mL of nanocomposite CeO2-Zn induced 50% cytotoxicity. Mechanism of cytotoxicity occurring due to nanocomposite by its Zn content was compared by choosing NPs of ZnO, possibly the closest nanoparticulate form of Zn. ZnO NPs lead to the induction of higher reactive oxygen species (ROS) (DCF-fluorescence), steeper depletion in antioxidant glutathione (GSH) and a greater loss of mitochondrial membrane potential (MMP) as compared to that induced by CeO2-Zn nanocomposite. Nanocomposite of CeO2-Zn, on the other hand, lead to significant higher induction of superoxide radical (O2•−, DHE fluorescence), nitric oxide (NO, determined by DAR-2 imaging and Griess reagent) and autophagic vesicles (determined by Lysotracker and monodansylcadeverine probes) as compared to that caused by ZnO NP treatment. Moreover, analysis after triple staining (by annexin V-FITC, PI, and Hoechst) conducted at their respective IC50s revealed an apoptosis mode of cell death due to ZnO NPs, whereas CeO2-Zn nanocomposite induced a mechanism of cell death that was significantly different from apoptosis. Our findings on advanced biomarkers such as autophagy and mode of cell death suggested the CeO2-Zn nanocomposite might behave as independent nanostructure from its constituent ones. Since nanocomposites can behave independently of their constituent NPs/elements, by creating nanocomposites, NP versatility can be increased manifold by just manipulating existing NPs. Moreover, data in this study can furnish early mechanistic insight about the potential damage that could occur in the integrity of vascular systems.
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Zhang L, Liu F, Xue J, Lee SA, Liu L, Riordan SM. Bacterial Species Associated With Human Inflammatory Bowel Disease and Their Pathogenic Mechanisms. Front Microbiol 2022; 13:801892. [PMID: 35283816 PMCID: PMC8908260 DOI: 10.3389/fmicb.2022.801892] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 01/25/2022] [Indexed: 12/17/2022] Open
Abstract
Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract with unknown etiology. The pathogenesis of IBD results from immune responses to microbes in the gastrointestinal tract. Various bacterial species that are associated with human IBD have been identified. However, the microbes that trigger the development of human IBD are still not clear. Here we review bacterial species that are associated with human IBD and their pathogenic mechanisms to provide an updated broad understanding of this research field. IBD is an inflammatory syndrome rather than a single disease. We propose a three-stage pathogenesis model to illustrate the roles of different IBD-associated bacterial species and gut commensal bacteria in the development of human IBD. Finally, we recommend microbe-targeted therapeutic strategies based on the three-stage pathogenesis model.
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Affiliation(s)
- Li Zhang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
- *Correspondence: Li Zhang,
| | - Fang Liu
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Jessica Xue
- Faculty of Medicine, Monash University, Melbourne, VIC, Australia
| | - Seul A. Lee
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Lu Liu
- School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Stephen M. Riordan
- Gastrointestinal and Liver Unit, Prince of Wales Hospital, University of New South Wales, Sydney, NSW, Australia
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Inhibition of Clostridium difficile TcdA and TcdB toxins with transition state analogues. Nat Commun 2021; 12:6285. [PMID: 34725358 PMCID: PMC8560925 DOI: 10.1038/s41467-021-26580-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 10/11/2021] [Indexed: 12/20/2022] Open
Abstract
Clostridium difficile causes life-threatening diarrhea and is the leading cause of healthcare-associated bacterial infections in the United States. TcdA and TcdB bacterial toxins are primary determinants of disease pathogenesis and are attractive therapeutic targets. TcdA and TcdB contain domains that use UDP-glucose to glucosylate and inactivate host Rho GTPases, resulting in cytoskeletal changes causing cell rounding and loss of intestinal integrity. Transition state analysis revealed glucocationic character for the TcdA and TcdB transition states. We identified transition state analogue inhibitors and characterized them by kinetic, thermodynamic and structural analysis. Iminosugars, isofagomine and noeuromycin mimic the transition state and inhibit both TcdA and TcdB by forming ternary complexes with Tcd and UDP, a product of the TcdA- and TcdB-catalyzed reactions. Both iminosugars prevent TcdA- and TcdB-induced cytotoxicity in cultured mammalian cells by preventing glucosylation of Rho GTPases. Iminosugar transition state analogues of the Tcd toxins show potential as therapeutics for C. difficile pathology. The Clostridium difficile virulence factors TcdA and TcdB contain a glucosyltransferase domain (GTD), which has both glucohydrolase (GH) and glucosyltransferase (GT) activities. Here, the authors characterize the transition state features of the TcdA and TcdB GH reactions by measuring kinetic isotope effects and they identify two transition state analogues, isofagomine and noeuromycin that inhibit TcdA and TcdB. They also present the crystal structures of TcdB-GTD bound to these inhibitors and the reaction product UDP.
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The role of the globular heads of the C1q receptor in TcdA-induced human colonic epithelial cell apoptosis via a mitochondria-dependent pathway. BMC Microbiol 2020; 20:274. [PMID: 32878596 PMCID: PMC7465811 DOI: 10.1186/s12866-020-01958-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 08/25/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Clostridioides (formerly Clostridium) difficile infection is the leading cause of antibiotic-associated colitis. Studies have demonstrated that C. difficile toxin A (TcdA) can cause apoptosis of many human cell types. The purpose of this study was to investigate the relationships among exposure to TcdA, the role of the receptor for the globular heads of C1q (gC1qR) gene and the underlying intracellular apoptotic mechanism in human colonic epithelial cells (NCM 460). In this study, gC1qR expression was examined using real-time polymerase chain reaction (PCR), western blotting and immunohistochemical staining. Cell viability was assessed by the water-soluble tetrazolium salt (WST-1) assay, and cell apoptosis was assessed by flow cytometry and the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay. Mitochondrial function was assessed based on reactive oxygen species (ROS) generation, changes in the mitochondrial membrane potential (ΔΨm) and the content of ATP. RESULTS Our study demonstrated that increasing the concentration of TcdA from 10 ng/ml to 20 ng/ml inhibited cell viability and induced cell apoptosis (p < 0.01). Moreover, the TcdA-induced gC1qR expression and enhanced expression of gC1qR caused mitochondrial dysfunction (including production of ROS and decreases in the ΔΨm and the content of ATP) and cell apoptosis. However, silencing of the gC1qR gene reversed TcdA-induced cell apoptosis and mitochondrial dysfunction. CONCLUSION These data support a mechanism by which gC1qR plays a crucial role in TcdA-induced apoptosis of human colonic epithelial cells in a mitochondria-dependent manner.
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Intestinal bile acids directly modulate the structure and function of C. difficile TcdB toxin. Proc Natl Acad Sci U S A 2020; 117:6792-6800. [PMID: 32152097 DOI: 10.1073/pnas.1916965117] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Intestinal bile acids are known to modulate the germination and growth of Clostridioides difficile Here we describe a role for intestinal bile acids in directly binding and neutralizing TcdB toxin, the primary determinant of C. difficile disease. We show that individual primary and secondary bile acids reversibly bind and inhibit TcdB to varying degrees through a mechanism that requires the combined oligopeptide repeats region to which no function has previously been ascribed. We find that bile acids induce TcdB into a compact "balled up" conformation that is no longer able to bind cell surface receptors. Lastly, through a high-throughput screen designed to identify bile acid mimetics we uncovered nonsteroidal small molecule scaffolds that bind and inhibit TcdB through a bile acid-like mechanism. In addition to suggesting a role for bile acids in C. difficile pathogenesis, these findings provide a framework for development of a mechanistic class of C. difficile antitoxins.
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Mehrbod P, Ebrahimi SN, Fotouhi F, Eskandari F, Eloff JN, McGaw LJ, Fasina FO. Experimental validation and computational modeling of anti-influenza effects of quercetin-3-O-α-L-rhamnopyranoside from indigenous south African medicinal plant Rapanea melanophloeos. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 19:346. [PMID: 31791311 PMCID: PMC6888925 DOI: 10.1186/s12906-019-2774-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 11/27/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND Influenza A virus (IAV) is still a major health threat. The clinical manifestations of this infection are related to immune dysregulation, which causes morbidity and mortality. The usage of traditional medication with immunomodulatory properties against influenza infection has been increased recently. Our previous study showed antiviral activity of quercetin-3-O-α-L-rhamnopyranoside (Q3R) isolated from Rapanea melanophloeos (RM) (L.) Mez (family Myrsinaceae) against H1N1 (A/PR/8/34) infection. This study aimed to confirm the wider range of immunomodulatory effect of Q3R on selective pro- and anti-inflammatory cytokines against IAV in vitro, to evaluate the effect of Q3R on apoptosis pathway in combination with H1N1, also to assess the physical interaction of Q3R with virus glycoproteins and RhoA protein using computational docking. METHODS MDCK cells were exposed to Q3R and 100CCID50/100 μl of H1N1 in combined treatments (co-, pre- and post-penetration treatments). The treatments were tested for the cytokines evaluation at RNA and protein levels by qPCR and ELISA, respectively. In another set of treatment, apoptosis was examined by detecting RhoA GTPase protein and caspase-3 activity. Molecular docking was used as a tool for evaluation of the potential anti-influenza activity of Q3R. RESULTS The expressions of cytokines in both genome and protein levels were significantly affected by Q3R treatment. It was shown that Q3R was much more effective against influenza when it was applied in co-penetration treatment. Q3R in combination with H1N1 increased caspase-3 activity while decreasing RhoA activation. The molecular docking results showed strong binding ability of Q3R with M2 transmembrane, Neuraminidase of 2009 pandemic H1N1, N1 and H1 of PR/8/1934 and Human RhoA proteins, with docking energy of - 10.81, - 10.47, - 9.52, - 9.24 and - 8.78 Kcal/mol, respectively. CONCLUSIONS Quercetin-3-O-α-L-rhamnopyranoside from RM was significantly effective against influenza infection by immunomodulatory properties, affecting the apoptosis pathway and binding ability to viral receptors M2 transmembrane and Neuraminidase of 2009 pandemic H1N1 and human RhoA cellular protein. Further research will focus on detecting the detailed specific mechanism of Q3R in virus-host interactions.
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Affiliation(s)
- Parvaneh Mehrbod
- Influenza and Respiratory Viruses Department, Pasteur Institute of Iran, Tehran, Iran
- Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa
| | - Samad Nejad Ebrahimi
- Department of Phytochemistry, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Tehran, Iran
| | - Fatemeh Fotouhi
- Influenza and Respiratory Viruses Department, Pasteur Institute of Iran, Tehran, Iran
| | - Fatemeh Eskandari
- Influenza and Respiratory Viruses Department, Pasteur Institute of Iran, Tehran, Iran
| | - Jacobus N. Eloff
- Phytomedicine Programme, Department of Paraclinical Sciences, University of Pretoria, Pretoria, South Africa
| | - Lyndy J. McGaw
- Phytomedicine Programme, Department of Paraclinical Sciences, University of Pretoria, Pretoria, South Africa
| | - Folorunso O. Fasina
- Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa
- ECTAD, Food and Agriculture Organization of the United Nations (FAO), Dar es Salaam, Tanzania
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12
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Rahim K, Huo L, Li C, Zhang P, Basit A, Xiang B, Ting B, Hao X, Zhu X. Identification of a basidiomycete-specific Vilse-like GTPase activating proteins (GAPs) and its roles in the production of virulence factors in Cryptococcus neoformans. FEMS Yeast Res 2019; 17:4644832. [PMID: 29177429 DOI: 10.1093/femsyr/fox089] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 11/20/2017] [Indexed: 12/25/2022] Open
Abstract
Cryptococcus neoformans is a basidiomycetous pathogenic yeast that causes fatal infections in both immunocompetent and immunocompromised patients. Regulation on the production of its virulence factors is not fully understood. Here we reported the characterization of a gene, named CVH1(CNA06260), encoding a Drosophila Vilse-like RhoGAP homolog, which is hallmarked by three conserved functional domains: WW, MyTH4 and RhoGAP. Phylogenetic analysis suggests that CVH1 is highly conserved from protists to mammals and interestingly in basidiomycetes, but absent in plants or Ascomycota and other lower fungi. This phylogenetic distribution indicates an evolutionary link among these groups of organisms. Functional analyses demonstrated that CVH1 was involved in stress tolerance and virulence factor production. By disrupting CVH1, we created a second mutant cvh1Δ with the CRISPR-Cas9 editing tool. The mutant strain exhibited hypersensitivity to osmotic stress by 2 M sorbitol and NaCl, suggesting defects in the HOG signaling pathway and an interaction of Cvh1 with the HOG pathway. Hypersensitivity of cvh1Δ to 1% Congo red and 0.01% SDS suggests that the cell wall integrity was impaired in the mutant. And cvh1Δ hardly produced the pigment melanin and capsule. Our study for the first time demonstrates that the fungal Vilse-like RhoGAP CVH1 is an important regulator of multiple biological processes in C. neoformans, and provides novel insights into the regulatory circuit of stress resistance/cell wall integrity, and laccase and capsule synthesis in C. neoformans.
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Affiliation(s)
- Kashif Rahim
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Liang Huo
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Chenxi Li
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Ping Zhang
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Abdul Basit
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Biyun Xiang
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Bie Ting
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Xiaoran Hao
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Xudong Zhu
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
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13
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Abstract
Clostridium difficile is the cause of antibiotics-associated diarrhea and pseudomembranous colitis. The pathogen produces three protein toxins: C. difficile toxins A (TcdA) and B (TcdB), and C. difficile transferase toxin (CDT). The single-chain toxins TcdA and TcdB are the main virulence factors. They bind to cell membrane receptors and are internalized. The N-terminal glucosyltransferase and autoprotease domains of the toxins translocate from low-pH endosomes into the cytosol. After activation by inositol hexakisphosphate (InsP6), the autoprotease cleaves and releases the glucosyltransferase domain into the cytosol, where GTP-binding proteins of the Rho/Ras family are mono-O-glucosylated and, thereby, inactivated. Inactivation of Rho proteins disturbs the organization of the cytoskeleton and affects multiple Rho-dependent cellular processes, including loss of epithelial barrier functions, induction of apoptosis, and inflammation. CDT, the third C. difficile toxin, is a binary actin-ADP-ribosylating toxin that causes depolymerization of actin, thereby inducing formation of the microtubule-based protrusions. Recent progress in understanding of the toxins' actions include insights into the toxin structures, their interaction with host cells, and functional consequences of their actions.
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Affiliation(s)
- Klaus Aktories
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany; , ,
| | - Carsten Schwan
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany; , ,
| | - Thomas Jank
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany; , ,
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14
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Fettucciari K, Ponsini P, Gioè D, Macchioni L, Palumbo C, Antonelli E, Coaccioli S, Villanacci V, Corazzi L, Marconi P, Bassotti G. Enteric glial cells are susceptible to Clostridium difficile toxin B. Cell Mol Life Sci 2017; 74:1527-1551. [PMID: 27891552 PMCID: PMC11107567 DOI: 10.1007/s00018-016-2426-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 10/27/2016] [Accepted: 11/21/2016] [Indexed: 02/06/2023]
Abstract
Clostridium difficile causes nosocomial/antibiotic-associated diarrhoea and pseudomembranous colitis. The major virulence factors are toxin A and toxin B (TcdB), which inactivate GTPases by monoglucosylation, leading to cytopathic (cytoskeleton alteration, cell rounding) and cytotoxic effects (cell-cycle arrest, apoptosis). C. difficile toxins breaching the intestinal epithelial barrier can act on underlying cells, enterocytes, colonocytes, and enteric neurons, as described in vitro and in vivo, but until now no data have been available on enteric glial cell (EGC) susceptibility. EGCs are crucial for regulating the enteric nervous system, gut homeostasis, the immune and inflammatory responses, and digestive and extradigestive diseases. Therefore, we evaluated the effects of C. difficile TcdB in EGCs. Rat-transformed EGCs were treated with TcdB at 0.1-10 ng/ml for 1.5-48 h, and several parameters were analysed. TcdB induces the following in EGCs: (1) early cell rounding with Rac1 glucosylation; (2) early G2/M cell-cycle arrest by cyclin B1/Cdc2 complex inactivation caused by p27 upregulation, the downregulation of cyclin B1 and Cdc2 phosphorylated at Thr161 and Tyr15; and (3) apoptosis by a caspase-dependent but mitochondria-independent pathway. Most importantly, the stimulation of EGCs with TNF-α plus IFN-γ before, concomitantly or after TcdB treatment strongly increased TcdB-induced apoptosis. Furthermore, EGCs that survived the cytotoxic effect of TcdB did not recover completely and showed not only persistent Rac1 glucosylation, cell-cycle arrest and low apoptosis but also increased production of glial cell-derived neurotrophic factor, suggesting self-rescuing mechanisms. In conclusion, the high susceptibility of EGCs to TcdB in vitro, the increased sensitivity to inflammatory cytokines related to apoptosis and the persistence of altered functions in surviving cells suggest an important in vivo role of EGCs in the pathogenesis of C. difficile infection.
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Affiliation(s)
- Katia Fettucciari
- Department of Experimental Medicine, Histology and Medical Embryology Section, Perugia University, Piazza Lucio Severi 1, Edificio B IV piano, Sant'Andrea delle Fratte, 06132, Perugia, Italy.
| | - Pamela Ponsini
- Department of Experimental Medicine, Histology and Medical Embryology Section, Perugia University, Piazza Lucio Severi 1, Edificio B IV piano, Sant'Andrea delle Fratte, 06132, Perugia, Italy
| | - Davide Gioè
- Department of Experimental Medicine, Histology and Medical Embryology Section, Perugia University, Piazza Lucio Severi 1, Edificio B IV piano, Sant'Andrea delle Fratte, 06132, Perugia, Italy
| | - Lara Macchioni
- Department of Experimental Medicine, Physiology and Biochemistry Section, Perugia University, Perugia, Italy
| | - Camilla Palumbo
- Department of Clinical Sciences and Translational Medicine, Tor Vergata University, Rome, Italy
| | | | - Stefano Coaccioli
- Department of Medicine, Internal Medicine, Rheumatology and Medical Therapy of Pain Section, Perugia University, District of Terni, Perugia, Italy
| | | | - Lanfranco Corazzi
- Department of Experimental Medicine, Physiology and Biochemistry Section, Perugia University, Perugia, Italy
| | - Pierfrancesco Marconi
- Department of Experimental Medicine, Histology and Medical Embryology Section, Perugia University, Piazza Lucio Severi 1, Edificio B IV piano, Sant'Andrea delle Fratte, 06132, Perugia, Italy
| | - Gabrio Bassotti
- Department of Medicine, Gastroenterology, Hepatology and Digestive Endoscopy Section, Perugia University, Perugia, Italy
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15
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Chen S, Sun C, Gu H, Wang H, Li S, Ma Y, Wang J. Salubrinal protects against Clostridium difficile toxin B-induced CT26 cell death. Acta Biochim Biophys Sin (Shanghai) 2017; 49:228-237. [PMID: 28119311 DOI: 10.1093/abbs/gmw139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile (C. difficile) is considered to be the major cause of the antibiotic-associated diarrhea and pseudomembranous colitis in animals and humans. The prevalence of C. difficile infections (CDI) has been increasing since 2000. Two exotoxins of C. difficile, Toxin A (TcdA) and Toxin B (TcdB), are the main virulence factors of CDI, which can induce glucosylation of Rho GTPases in host cytosol, leading to cell morphological changes, cell apoptosis, and cell death. The mechanism of TcdB-induced cell death has been investigated for decades, but it is still not completely understood. It has been reported that TcdB induces endoplasmic reticulum stress via PERK-eIF2α signaling pathway in CT26 cell line (BALB/C mouse colon tumor cells). In this study, we found that salubrinal, a selective inhibitor of eIF2α dephosphorylation, efficiently protects CT26 cell line against TcdB-induced cell death and tried to explore the mechanism underlying in this protective effect. Our results demonstrated that salubrinal protects CT26 cells from TcdB-mediated cytotoxic and cytopathic effect, inhibits apoptosis and death of the toxin-exposed cells via caspase-9-dependent pathway, eIF2α signaling pathway, and autophagy. These findings will be helpful for the development of CDI therapies.
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Affiliation(s)
- Shuyi Chen
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Chunli Sun
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Huawei Gu
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Haiying Wang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Shan Li
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Yi Ma
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Jufang Wang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
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16
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Secore S, Wang S, Doughtry J, Xie J, Miezeiewski M, Rustandi RR, Horton M, Xoconostle R, Wang B, Lancaster C, Kristopeit A, Wang SC, Christanti S, Vitelli S, Gentile MP, Goerke A, Skinner J, Strable E, Thiriot DS, Bodmer JL, Heinrichs JH. Development of a Novel Vaccine Containing Binary Toxin for the Prevention of Clostridium difficile Disease with Enhanced Efficacy against NAP1 Strains. PLoS One 2017; 12:e0170640. [PMID: 28125650 PMCID: PMC5268477 DOI: 10.1371/journal.pone.0170640] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 01/06/2017] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile infections (CDI) are a leading cause of nosocomial diarrhea in the developed world. The main virulence factors of the bacterium are the large clostridial toxins (LCTs), TcdA and TcdB, which are largely responsible for the symptoms of the disease. Recent outbreaks of CDI have been associated with the emergence of hypervirulent strains, such as NAP1/BI/027, many strains of which also produce a third toxin, binary toxin (CDTa and CDTb). These hypervirulent strains have been associated with increased morbidity and higher mortality. Here we present pre-clinical data describing a novel tetravalent vaccine composed of attenuated forms of TcdA, TcdB and binary toxin components CDTa and CDTb. We demonstrate, using the Syrian golden hamster model of CDI, that the inclusion of binary toxin components CDTa and CDTb significantly improves the efficacy of the vaccine against challenge with NAP1 strains in comparison to vaccines containing only TcdA and TcdB antigens, while providing comparable efficacy against challenge with the prototypic, non-epidemic strain VPI10463. This combination vaccine elicits high neutralizing antibody titers against TcdA, TcdB and binary toxin in both hamsters and rhesus macaques. Finally we present data that binary toxin alone can act as a virulence factor in animal models. Taken together, these data strongly support the inclusion of binary toxin in a vaccine against CDI to provide enhanced protection from epidemic strains of C. difficile.
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Affiliation(s)
- Susan Secore
- Vaccine Basic Research, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Su Wang
- Vaccine Basic Research, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Julie Doughtry
- Vaccine Basic Research, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Jinfu Xie
- Vaccine Basic Research, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Matt Miezeiewski
- Eurofins Laboratories, Lancaster, Pennsylvania, United States of America
| | - Richard R. Rustandi
- Vaccine Analytical Development, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Melanie Horton
- Vaccine Basic Research, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Rachel Xoconostle
- Vaccine Basic Research, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Bei Wang
- Vaccine Drug Product Development, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Catherine Lancaster
- Vaccine Analytical Development, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Adam Kristopeit
- Vaccine Process Development, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Sheng-Ching Wang
- Vaccine Process Development, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Sianny Christanti
- Vaccine Process Development, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Salvatore Vitelli
- Vaccine Analytical Development, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Marie-Pierre Gentile
- Vaccine Process Development, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Aaron Goerke
- Vaccine Process Development, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Julie Skinner
- Vaccine Basic Research, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Erica Strable
- Vaccine Drug Product Development, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - David S. Thiriot
- Vaccine Drug Product Development, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Jean-Luc Bodmer
- Vaccine Basic Research, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
| | - Jon H. Heinrichs
- Vaccine Basic Research, Merck Research Laboratories, Merck and Company, Incorporated, West Point, Pennsylvania, United States of America
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17
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Dai Y, Jin S, Li X, Wang D. The involvement of Bcl-2 family proteins in AKT-regulated cell survival in cisplatin resistant epithelial ovarian cancer. Oncotarget 2016; 8:1354-1368. [PMID: 27935869 PMCID: PMC5352061 DOI: 10.18632/oncotarget.13817] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 11/08/2016] [Indexed: 11/29/2022] Open
Abstract
Many studies involving patients with cisplatin-resistant ovarian cancer have shown that AKT activation leads to inhibition of apoptosis. The aim of this study was to examine the potential involvement of the Bcl-2 family proteins in AKT-regulated cell survival in response to cisplatin treatment. Cisplatin-sensitive (PEO1) and cisplatin-resistant (PEO4) cells were taken from ascites of patients with ovarian cancer before cisplatin treatment and after development of chemoresistance. It was found that cisplatin treatment activated the AKT signaling pathway and promoted cell proliferation in cisplatin-resistant EOC cells. When AKT was transfected into nucleus of cisplatin-resistant ovarian cancer cells, DNA-PK was phosphorylated at S473. The activated AKT (pAKT-S473) in these cells inhibited the death signal induced by cisplatin thereby inhibiting cisplatin-mediated apoptosis. Results from this study showed that the combination of cisplatin, DNA-PK inhibitor NU7441, and AKT inhibitor TCN can overcome drug resistance, increase apoptosis, and re-sensitize PEO4 cells to cisplatin treatment. A decrease in apoptotic activity was seen in PEO4 cells when Bad was downregulated by siRNA, which indicated that Bad promotes apoptosis in PEO4 cells. Use of the Bcl-2 inhibitor ABT-737 showed that ABT-737 binds to Bcl-2 but not Mcl-1 and releases Bax/Bak which leads to cell apoptosis. The combination of ABT-737 and cisplatin leads to a significant increase in the death of PEO1 and PEO4 cells. All together, these results indicate that Bcl-2 family proteins are regulators of drug resistance. The combination of cisplatin and Bcl-2 family protein inhibitor could be a strategy for the treatment of cisplatin-resistant ovarian cancer.
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Affiliation(s)
- Yan Dai
- 1 The Second Xiangya Hospital of Central South University, Changsha, China
| | - Shiguang Jin
- 2 Clinical Medical College, Yangzhou University, Yangzhou, China,3 Medical Research Centre, Northern Jiangsu People's Hospital, Yangzhou, China
| | - Xueping Li
- 4 Nanjing Hospital Affiliated to Nanjing Medical University, The First Hospital of Nanjing, Nanjing, China
| | - Daxin Wang
- 2 Clinical Medical College, Yangzhou University, Yangzhou, China,3 Medical Research Centre, Northern Jiangsu People's Hospital, Yangzhou, China
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18
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Yang G, Qian C, Wang N, Lin C, Wang Y, Wang G, Piao X. Tetramethylpyrazine Protects Against Oxygen-Glucose Deprivation-Induced Brain Microvascular Endothelial Cells Injury via Rho/Rho-kinase Signaling Pathway. Cell Mol Neurobiol 2016; 37:619-633. [DOI: 10.1007/s10571-016-0398-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 06/22/2016] [Indexed: 01/24/2023]
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19
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Di Bella S, Ascenzi P, Siarakas S, Petrosillo N, di Masi A. Clostridium difficile Toxins A and B: Insights into Pathogenic Properties and Extraintestinal Effects. Toxins (Basel) 2016; 8:E134. [PMID: 27153087 PMCID: PMC4885049 DOI: 10.3390/toxins8050134] [Citation(s) in RCA: 147] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/22/2016] [Accepted: 04/25/2016] [Indexed: 02/06/2023] Open
Abstract
Clostridium difficile infection (CDI) has significant clinical impact especially on the elderly and/or immunocompromised patients. The pathogenicity of Clostridium difficile is mainly mediated by two exotoxins: toxin A (TcdA) and toxin B (TcdB). These toxins primarily disrupt the cytoskeletal structure and the tight junctions of target cells causing cell rounding and ultimately cell death. Detectable C. difficile toxemia is strongly associated with fulminant disease. However, besides the well-known intestinal damage, recent animal and in vitro studies have suggested a more far-reaching role for these toxins activity including cardiac, renal, and neurologic impairment. The creation of C. difficile strains with mutations in the genes encoding toxin A and B indicate that toxin B plays a major role in overall CDI pathogenesis. Novel insights, such as the role of a regulator protein (TcdE) on toxin production and binding interactions between albumin and C. difficile toxins, have recently been discovered and will be described. Our review focuses on the toxin-mediated pathogenic processes of CDI with an emphasis on recent studies.
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Affiliation(s)
- Stefano Di Bella
- 2nd Infectious Diseases Division, National Institute for Infectious Diseases "L. Spallanzani", Rome 00149, Italy.
| | - Paolo Ascenzi
- Department of Science, Roma Tre University, Rome 00154, Italy.
| | - Steven Siarakas
- Department of Microbiology and Infectious Diseases, Concord Repatriation General Hospital, Sydney 2139, Australia.
| | - Nicola Petrosillo
- 2nd Infectious Diseases Division, National Institute for Infectious Diseases "L. Spallanzani", Rome 00149, Italy.
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20
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Zhang Y, Feng H. Pathogenic effects of glucosyltransferase from Clostridium difficile toxins. Pathog Dis 2016; 74:ftw024. [PMID: 27044305 DOI: 10.1093/femspd/ftw024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2016] [Indexed: 01/13/2023] Open
Abstract
The glucosyltransferase domain ofClostridium difficiletoxins modifies guanine nucleotide-binding proteins of Rho family. It is the major virulent domain of the holotoxins. Various pathogenic effects ofC. difficiletoxins in response to Rho glucosylation have been investigated including cytoskeleton damage, cell death and inflammation. The most recent studies have revealed some significant characteristics of the holotoxins that are independent of glucosylating activity. These findings arouse discussion about the role of glucosyltransferase activity in toxin pathogenesis and open up new insights for toxin mechanism study. In this review, we summarize the pathogenic effects of glucosyltransferase domain of the toxins in the past years.
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Affiliation(s)
- Yongrong Zhang
- Department of Microbial Pathogenesis, University of Maryland Baltimore, 650 W. Baltimore Street, Baltimore, MD 21201, USA
| | - Hanping Feng
- Department of Microbial Pathogenesis, University of Maryland Baltimore, 650 W. Baltimore Street, Baltimore, MD 21201, USA
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21
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Watson EC, Whitehead L, Adams RH, Dewson G, Coultas L. Endothelial cell survival during angiogenesis requires the pro-survival protein MCL1. Cell Death Differ 2016; 23:1371-9. [PMID: 26943318 DOI: 10.1038/cdd.2016.20] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 01/07/2016] [Accepted: 01/29/2016] [Indexed: 01/31/2023] Open
Abstract
Angiogenesis is essential to match the size of blood vessel networks to the metabolic demands of growing tissues. While many genes and pathways necessary for regulating angiogenesis have been identified, those responsible for endothelial cell (EC) survival during angiogenesis remain largely unknown. We have investigated the in vivo role of myeloid cell leukemia 1 (MCL1), a pro-survival member of the BCL2 family, in EC survival during angiogenesis. EC-specific deletion of Mcl1 resulted in a dose-dependent increase in EC apoptosis in the angiogenic vasculature and a corresponding decline in vessel density. Our results suggest this apoptosis was independent of the BH3-only protein BIM. Despite the known link between apoptosis and blood vessel regression, this was not the cause of reduced vessel density observed in the absence of endothelial MCL1. Rather, the reduction in vessel density was linked to ectopic apoptosis in regions of the angiogenic vasculature where EC proliferation and new vessel growth occurs. We have therefore identified MCL1 as an essential survival factor for ECs that is required for blood vessel production during angiogenesis.
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Affiliation(s)
- E C Watson
- Development and Cancer Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia.,Department of Medical Biology, University of Melbourne, 1G Royal Parade, VIC, Australia
| | - L Whitehead
- Department of Medical Biology, University of Melbourne, 1G Royal Parade, VIC, Australia.,Systems Biology and Personalised Medicine Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
| | - R H Adams
- Department of Tissue Morphogenesis, Max Planck Institute for Molecular Biomedicine, Roentgenstrasse 20, Münster D, Germany.,Faculty of Medicine, University of Münster, Münster D, Germany
| | - G Dewson
- Department of Medical Biology, University of Melbourne, 1G Royal Parade, VIC, Australia.,Cell Signalling and Cell Death Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia
| | - L Coultas
- Development and Cancer Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, Australia.,Department of Medical Biology, University of Melbourne, 1G Royal Parade, VIC, Australia
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Chen S, Sun C, Wang H, Wang J. The Role of Rho GTPases in Toxicity of Clostridium difficile Toxins. Toxins (Basel) 2015; 7:5254-67. [PMID: 26633511 PMCID: PMC4690124 DOI: 10.3390/toxins7124874] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/18/2015] [Accepted: 11/18/2015] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile (C. difficile) is the main cause of antibiotic-associated diarrhea prevailing in hospital settings. In the past decade, the morbidity and mortality of C. difficile infection (CDI) has increased significantly due to the emergence of hypervirulent strains. Toxin A (TcdA) and toxin B (TcdB), the two exotoxins of C. difficile, are the major virulence factors of CDI. The common mode of action of TcdA and TcdB is elicited by specific glucosylation of Rho-GTPase proteins in the host cytosol using UDP-glucose as a co-substrate, resulting in the inactivation of Rho proteins. Rho proteins are the key members in many biological processes and signaling pathways, inactivation of which leads to cytopathic and cytotoxic effects and immune responses of the host cells. It is supposed that Rho GTPases play an important role in the toxicity of C. difficile toxins. This review focuses on recent progresses in the understanding of functional consequences of Rho GTPases glucosylation induced by C. difficile toxins and the role of Rho GTPases in the toxicity of TcdA and TcdB.
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Affiliation(s)
- Shuyi Chen
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
| | - Chunli Sun
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
| | - Haiying Wang
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
| | - Jufang Wang
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
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The Makes Caterpillars Floppy (MCF)-Like Domain of Vibrio vulnificus Induces Mitochondrion-Mediated Apoptosis. Infect Immun 2015; 83:4392-403. [PMID: 26351282 DOI: 10.1128/iai.00570-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Accepted: 08/26/2015] [Indexed: 12/17/2022] Open
Abstract
The multifunctional-autoprocessing repeats-in-toxin (MARTXVv) toxin of Vibrio vulnificus plays a significant role in the pathogenesis of this bacterium through delivery of up to five effector domains to the host cells. Previous studies have established that the MARTXVv toxin is linked to V. vulnificus dependent induction of apoptosis, but the region of the large multifunction protein essential for this activity was not previously identified. Recently, we showed that the Makes Caterpillar Floppy-like MARTX effector domain (MCFVv) is an autoproteolytic cysteine protease that induces rounding of various cell types. In this study, we demonstrate that cell rounding induced by MCFVv is coupled to reduced metabolic rate and inhibition of cellular proliferation. Moreover, delivery of MCFVv into host cells either as a fusion to the N-terminal fragment of anthrax toxin lethal factor or when naturally delivered as a V. vulnificus MARTX toxin led to loss of mitochondrial membrane potential, release of cytochrome c, activation of Bax and Bak, and processing of caspases and poly-(ADP-ribose) polymerase (PARP-γ). These studies specifically link the MCFVv effector domain to induction of the intrinsic apoptosis pathway by V. vulnificus.
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Tam J, Beilhartz GL, Auger A, Gupta P, Therien AG, Melnyk RA. Small molecule inhibitors of Clostridium difficile toxin B-induced cellular damage. ACTA ACUST UNITED AC 2015; 22:175-85. [PMID: 25619932 DOI: 10.1016/j.chembiol.2014.12.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 11/25/2014] [Accepted: 12/06/2014] [Indexed: 02/04/2023]
Abstract
Clostridium difficile causes life-threatening diarrhea through the actions of its homologous toxins TcdA and TcdB on human colonocytes. Therapeutic agents that block toxin-induced damage are urgently needed to prevent the harmful consequences of toxin action that are not addressed with current antibiotic-based treatments. Here, we developed an imaging-based phenotypic screen to identify small molecules that protected human cells from TcdB-induced cell rounding. A series of structurally diverse compounds with antitoxin activity were identified and found to act through one of a small subset of mechanisms, including direct binding and sequestration of TcdB, inhibition of endosomal maturation, and noncompetitive inhibition of the toxin glucosyltransferase activity. Distinct classes of inhibitors were used further to dissect the determinants of the toxin-mediated necrosis phenotype occurring at higher doses of toxin. These findings validate and inform novel targeting strategies for discovering small molecule agents to treat C. difficile infection.
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Affiliation(s)
- John Tam
- Molecular Structure & Function, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Greg L Beilhartz
- Molecular Structure & Function, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Anick Auger
- Molecular Structure & Function, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Pulkit Gupta
- Merck & Co. Inc., 2000 Galloping Hill Road, K15, Kenilworth, NJ 07033, USA
| | - Alex G Therien
- Merck & Co. Inc., 2000 Galloping Hill Road, K15, Kenilworth, NJ 07033, USA
| | - Roman A Melnyk
- Molecular Structure & Function, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada.
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Toxin-mediated paracellular transport of antitoxin antibodies facilitates protection against Clostridium difficile infection. Infect Immun 2014; 83:405-16. [PMID: 25385797 DOI: 10.1128/iai.02550-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The exotoxins TcdA and TcdB are the major virulence factors of Clostridium difficile. Circulating neutralizing antitoxin antibodies are protective in C. difficile infection (CDI), as demonstrated, in part, by the protective effects of actoxumab and bezlotoxumab, which bind to and neutralize TcdA and TcdB, respectively. The question of how systemic IgG antibodies neutralize toxins in the gut lumen remains unresolved, although it has been suggested that the Fc receptor FcRn may be involved in active antibody transport across the gut epithelium. In this study, we demonstrated that genetic ablation of FcRn and excess irrelevant human IgG have no impact on actoxumab-bezlotoxumab-mediated protection in murine and hamster models of CDI, suggesting that Fc-dependent transport of antibodies across the gut wall is not required for efficacy. Tissue distribution studies in hamsters suggest, rather, that the transport of antibodies depends on toxin-induced damage to the gut lining. In an in vitro two-dimensional culture system that mimics the architecture of the intestinal mucosal epithelium, toxins on the apical side of epithelial cell monolayers are neutralized by basolateral antibodies, and antibody transport across the cell layer is dramatically increased upon addition of toxin to the apical side. Similar data were obtained with F(ab')2 fragments, which lack an Fc domain, consistent with FcRn-independent paracellular, rather than transcellular, transport of antibodies. Kinetic studies show that initial damage caused by apical toxin is required for efficient neutralization by basolateral antibodies. These data may represent a general mechanism of humoral response-mediated protection against enteric pathogens.
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Huang T, Li S, Li G, Tian Y, Wang H, Shi L, Perez-Cordon G, Mao L, Wang X, Wang J, Feng H. Utility of Clostridium difficile toxin B for inducing anti-tumor immunity. PLoS One 2014; 9:e110826. [PMID: 25340750 PMCID: PMC4207755 DOI: 10.1371/journal.pone.0110826] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 08/01/2014] [Indexed: 12/22/2022] Open
Abstract
Clostridium difficile toxin B (TcdB) is a key virulence factor of bacterium and induces intestinal inflammatory disease. Because of its potent cytotoxic and proinflammatory activities, we investigated the utility of TcdB in developing anti-tumor immunity. TcdB induced cell death in mouse colorectal cancer CT26 cells, and the intoxicated cells stimulated the activation of mouse bone marrow-derived dendritic cells and subsequent T cell activation in vitro. Immunization of BALB/c mice with toxin-treated CT26 cells elicited potent anti-tumor immunity that protected mice from a lethal challenge of the same tumor cells and rejected pre-injected tumors. The anti-tumor immunity generated was cell-mediated, long-term, and tumor-specific. Further experiments demonstrated that the intact cell bodies were important for the immunogenicity since lysing the toxin-treated tumor cells reduced their ability to induce antitumor immunity. Finally, we showed that TcdB is able to induce potent anti-tumor immunity in B16-F10 melanoma model. Taken together, these data demonstrate the utility of C. difficile toxin B for developing anti-tumor immunity.
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Affiliation(s)
- Tuxiong Huang
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou, China
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United States of America
| | - Shan Li
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou, China
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United States of America
| | - Guangchao Li
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou, China
| | - Yuan Tian
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou, China
| | - Haiying Wang
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou, China
| | - Lianfa Shi
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United States of America
| | - Gregorio Perez-Cordon
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United States of America
| | - Li Mao
- Department of Oncology and Diagnostics, University of Maryland Dental School, Baltimore, Maryland, United States of America
| | - Xiaoning Wang
- Institute of Life Science, General Hospital of the People’s Liberation Army, Beijing, China
| | - Jufang Wang
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou, China
- * E-mail: (JW); (HF)
| | - Hanping Feng
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, United States of America
- * E-mail: (JW); (HF)
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Labandeira-Garcia JL, Rodríguez-Perez AI, Villar-Cheda B, Borrajo A, Dominguez-Meijide A, Guerra MJ. Rho Kinase and Dopaminergic Degeneration. Neuroscientist 2014; 21:616-29. [DOI: 10.1177/1073858414554954] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The small GTP-binding protein Rho plays an important role in several cellular functions. RhoA, which is a member of the Rho family, initiates cellular processes that act on its direct downstream effector Rho-associated kinase (ROCK). ROCK inhibition protects against dopaminergic cell death induced by dopaminergic neurotoxins. It has been suggested that ROCK inhibition activates neuroprotective survival cascades in dopaminergic neurons. Axon-stabilizing effects in damaged neurons may represent another mechanism of neuroprotection of dopaminergic neurons by ROCK inhibition. However, it has been shown that microglial cells play a crucial role in neuroprotection by ROCK inhibition and that activation of microglial ROCK mediates major components of the microglial inflammatory response. Additional mechanisms such as interaction with autophagy may also contribute to the neuroprotective effects of ROCK inhibition. Interestingly, ROCK interacts with several brain factors that play a major role in dopaminergic neuron vulnerability such as NADPH-oxidase, angiotensin, and estrogen. ROCK inhibition may provide a new neuroprotective strategy for Parkinson’s disease. This is of particular interest because ROCK inhibitors are currently used against vascular diseases in clinical practice. However, it is necessary to develop more potent and selective ROCK inhibitors to reduce side effects and enhance the efficacy.
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Affiliation(s)
- Jose L. Labandeira-Garcia
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Ana I. Rodríguez-Perez
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Begoña Villar-Cheda
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Ana Borrajo
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Antonio Dominguez-Meijide
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Maria J. Guerra
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
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Wang Z, Pan X, Wang D, Sun H, Han F, Lv C, Zhang X. Protective effects of protocatechuic acid on retinal ganglion cells from oxidative damage induced by H2O2. Neurol Res 2014; 37:159-66. [DOI: 10.1179/1743132814y.0000000421] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Eisa-Beygi S, Ekker M, Moon TW, Macdonald RL, Wen XY. Developmental processes regulated by the 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) pathway: highlights from animal studies. Reprod Toxicol 2014; 46:115-20. [PMID: 24732207 DOI: 10.1016/j.reprotox.2014.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 03/13/2014] [Accepted: 04/02/2014] [Indexed: 12/20/2022]
Abstract
The 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) is the rate-limiting enzyme in the biosynthesis of cholesterol and isoprenoids, which are substrates required for post-translational modification of signalling proteins that can potentially regulate various aspects of embryonic development. The HMGCR transcripts are detectable during early embryogenesis in both invertebrates and vertebrates, which suggests a conserved developmental requirement for mevalonate derivatives. Consistently, recent animal and in vitro studies have yielded valuable insights into potential morphogenic parameters that are modulated by HMGCR activity. These developmental end-points include brain and craniofacial morphogenesis, PGC migration and survival, myocardial epithelial migration and fusion, EC migration and survival, and vascular stabilization. By providing a synthesis of these studies, we hope that this review will highlight the need to comprehensively examine the entire suite of developmental processes regulated by HMGCR.
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Affiliation(s)
- Shahram Eisa-Beygi
- Department of Biology, Centre for Advanced Research in Environmental Genomics (CAREG), University of Ottawa, ON, Canada; Zebrafish Centre for Advanced Drug Discovery, Keenan Research Centre of the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, ON, Canada; Institute of Medical Science & Department of Medicine, University of Toronto, ON, Canada.
| | - Marc Ekker
- Department of Biology, Centre for Advanced Research in Environmental Genomics (CAREG), University of Ottawa, ON, Canada
| | - Thomas W Moon
- Department of Biology, Centre for Advanced Research in Environmental Genomics (CAREG), University of Ottawa, ON, Canada
| | - R Loch Macdonald
- Zebrafish Centre for Advanced Drug Discovery, Keenan Research Centre of the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, ON, Canada; Institute of Medical Science & Department of Medicine, University of Toronto, ON, Canada; Division of Neurosurgery, St. Michael's Hospital, Labatt Family Centre of Excellence in Brain Injury and Trauma Research, Keenan Research Centre of the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, ON, Canada
| | - Xiao-Yan Wen
- Zebrafish Centre for Advanced Drug Discovery, Keenan Research Centre of the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, ON, Canada; Institute of Medical Science & Department of Medicine, University of Toronto, ON, Canada
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30
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KUANG JING, WANG YALAN, XIAO MING, TANG YI, CHEN WENWEN, SONG GUANGLIN, YANG XI, LI MING. Synergistic effect of arginine-specific ADP-ribosyltransferase 1 and poly(ADP-ribose) polymerase-1 on apoptosis induced by cisplatin in CT26 cells. Oncol Rep 2014; 31:2335-43. [DOI: 10.3892/or.2014.3100] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 03/06/2014] [Indexed: 11/06/2022] Open
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Translocation domain mutations affecting cellular toxicity identify the Clostridium difficile toxin B pore. Proc Natl Acad Sci U S A 2014; 111:3721-6. [PMID: 24567384 DOI: 10.1073/pnas.1400680111] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Disease associated with Clostridium difficile infection is caused by the actions of the homologous toxins TcdA and TcdB on colonic epithelial cells. Binding to target cells triggers toxin internalization into acidified vesicles, whereupon cryptic segments from within the 1,050-aa translocation domain unfurl and insert into the bounding membrane, creating a transmembrane passageway to the cytosol. Our current understanding of the mechanisms underlying pore formation and the subsequent translocation of the upstream cytotoxic domain to the cytosol is limited by the lack of information available regarding the identity and architecture of the transmembrane pore. Here, through systematic perturbation of conserved sites within predicted membrane-insertion elements of the translocation domain, we uncovered highly sensitive residues--clustered between amino acids 1,035 and 1,107--that when individually mutated, reduced cellular toxicity by as much as >1,000-fold. We demonstrate that defective variants are defined by impaired pore formation in planar lipid bilayers and biological membranes, resulting in an inability to intoxicate cells through either apoptotic or necrotic pathways. These findings along with the unexpected similarities uncovered between the pore-forming "hotspots" of TcdB and the well-characterized α-helical diphtheria toxin translocation domain provide insights into the structure and mechanism of formation of the translocation pore for this important class of pathogenic toxins.
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Caspase activation as a versatile assay platform for detection of cytotoxic bacterial toxins. J Clin Microbiol 2013; 51:2970-6. [PMID: 23824772 DOI: 10.1128/jcm.01161-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Pathogenic bacteria produce several virulence factors that help them establish infection in permissive hosts. Bacterial toxins are a major class of virulence factors and hence are attractive therapeutic targets for vaccine development. Here, we describe the development of a rapid, sensitive, and high-throughput assay that can be used as a versatile platform to measure the activities of bacterial toxins. We have exploited the ability of these toxins to cause cell death via apoptosis of sensitive cultured cell lines as a readout for measuring toxin activity. Caspases (cysteine-aspartic proteases) are induced early in the apoptotic pathway, and so we used their induction to measure the activities of Clostridium difficile toxins A (TcdA) and B (TcdB) and binary toxin (CDTa-CDTb), Corynebacterium diphtheriae toxin (DT), and Pseudomonas aeruginosa exotoxin A (PEA). Caspase induction in the cell lines, upon exposure to toxins, was optimized by toxin concentration and intoxication time, and the specificity of caspase activity was established using a genetically mutated toxin and a pan-caspase inhibitor. In addition, we demonstrate the utility of the caspase assay for measuring toxin potency, as well as neutralizing antibody (NAb) activity against C. difficile toxins. Furthermore, the caspase assay showed excellent correlation with the filamentous actin (F-actin) polymerization assay for measuring TcdA and TcdB neutralization titers upon vaccination of hamsters. These results demonstrate that the detection of caspase induction due to toxin exposure using a chemiluminescence readout can support potency and clinical immunogenicity testing for bacterial toxin vaccine candidates in development.
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Na RH, Zhu GH, Luo JX, Meng XJ, Cui L, Peng HJ, Chen XG, Gomez-Cambronero J. Enzymatically active Rho and Rac small-GTPases are involved in the establishment of the vacuolar membrane after Toxoplasma gondii invasion of host cells. BMC Microbiol 2013; 13:125. [PMID: 23721065 PMCID: PMC3681593 DOI: 10.1186/1471-2180-13-125] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 05/27/2013] [Indexed: 11/10/2022] Open
Abstract
Background GTPases are the family of hydrolases that bind and hydrolyze guanosine triphosphate. The large Immunity-related GTPases and the small GTPase ADP-ribosylation factor-6 in host cells are known to accumulate on the parasitophorous vacuole membrane (PVM) of Toxoplasma gondii and play critical roles in this parasite infection, but these GTPases cannot explain the full extent of infection. Results In this research, RhoA and Rac1 GTPases from the host cell were found to accumulate on the PVM regardless of the virulence of the T. gondii strains after T. gondii invasion, and this accumulation was dependent on their GTPase activity. The real-time micrography of T. gondii tachyzoites invading COS-7 cells overexpressing CFP-RhoA showed that this GTPase was recruited to the PVM at the very beginning of the invasion through the host cell membrane or from the cytosol. Host cell RhoA and Rac1 were also activated after T. gondii tachyzoites invasion, which was needed for host cell cytoskeleton reorganization to facilitate intracellular pathogens invasion. The decisive domains for the RhoA accumulation on the PVM included the GTP/Mg2+ binding site, the mDia effector interaction site, the G1 box, the G2 box and the G5 box, respectively, which were related to the binding of GTP for enzymatic activity and mDia for the regulation of microtubules. The recruited CFP-RhoA on the PVM could not be activated by epithelial growth factor (EGF) and no translocation was observed, unlike the unassociated RhoA in the host cell cytosol that migrated to the cell membrane towards the EGF activation spot. This result supported the hypothesis that the recruited RhoA or Rac1 on the PVM were in the GTP-bound active form. Wild-type RhoA or Rac1 overexpressed cells had almost the same infection rates by T. gondii as the mock-treated cells, while RhoA-N19 or Rac1-N17 transfected cells and RhoA, Rac1 or RhoA + Rac1 siRNA-treated cells showed significantly diminished infection rates compared to mock cells. Conclusions The accumulation of the RhoA and Rac1 on the PVM and the requisite of their normal GTPase activity for efficient invasion implied their involvement and function in T. gondii invasion.
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Affiliation(s)
- Ren-Hua Na
- Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, Department of Pathogen Biology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong 510515, China
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Wu D, Joyee AG, Nandagopal S, Lopez M, Ma X, Berry J, Lin F. Effects of Clostridium difficile toxin A and B on human T lymphocyte migration. Toxins (Basel) 2013; 5:926-38. [PMID: 23645153 PMCID: PMC3709270 DOI: 10.3390/toxins5050926] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 03/27/2013] [Accepted: 04/23/2013] [Indexed: 01/24/2023] Open
Abstract
Bacterial products such as toxins can interfere with a variety of cellular processes, leading to severe human diseases. Clostridium difficile toxins, TcdA and TcdB are the primary contributing factors to the pathogenesis of C. difficile-associated diseases (CDAD). While the mechanisms for TcdA and TcdB mediated cellular responses are complex, it has been shown that these toxins can alter chemotactic responses of neutrophils and intestinal epithelial cells leading to innate immune responses and tissue damages. The effects of C. difficile toxins on the migration and trafficking of other leukocyte subsets, such as T lymphocytes, are not clear and may have potential implications for adaptive immunity. We investigated here the direct and indirect effects of TcdA and TcdB on the migration of human blood T cells using conventional cell migration assays and microfluidic devices. It has been found that, although both toxins decrease T cell motility, only TcdA but not TcdB decreases T cell chemotaxis. Similar effects are observed in T cell migration toward the TcdA- or TcdB-treated human epithelial cells. Our study demonstrated the primary role of TcdA (compared to TcdB) in altering T cell migration and chemotaxis, suggesting possible implications for C. difficile toxin mediated adaptive immune responses in CDAD.
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Affiliation(s)
- Dan Wu
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; E-Mails: (D.W.); (S.N.); (X.M.)
| | - Antony George Joyee
- Cangene Corporation, Winnipeg, MB R3T 2N2, Canada; E-Mails: (A.G.J.); (J.B.)
- Department of Immunology, University of Manitoba, Winnipeg, MB R3E 0T5, Canada
| | - Saravanan Nandagopal
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; E-Mails: (D.W.); (S.N.); (X.M.)
- Department of Biosystems Engineering, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Marianela Lopez
- Department of Medical Microbiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada; E-Mail:
| | - Xiuli Ma
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; E-Mails: (D.W.); (S.N.); (X.M.)
| | - Jody Berry
- Cangene Corporation, Winnipeg, MB R3T 2N2, Canada; E-Mails: (A.G.J.); (J.B.)
- BD Biosciences, La Jolla, CA 92121, USA
| | - Francis Lin
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; E-Mails: (D.W.); (S.N.); (X.M.)
- Department of Immunology, University of Manitoba, Winnipeg, MB R3E 0T5, Canada
- Department of Biosystems Engineering, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-204-474-9895; Fax: +1-204-474-7622
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Lum MA, Pundt KE, Paluch BE, Black AR, Black JD. Agonist-induced down-regulation of endogenous protein kinase c α through an endolysosomal mechanism. J Biol Chem 2013; 288:13093-109. [PMID: 23508961 DOI: 10.1074/jbc.m112.437061] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Protein kinase C (PKC) isozymes undergo down-regulation upon sustained stimulation. Previous studies have pointed to the existence of both proteasome-dependent and -independent pathways of PKCα processing. Here we demonstrate that these down-regulation pathways are engaged in different subcellular compartments; proteasomal degradation occurs mainly at the plasma membrane, whereas non-proteasomal processing occurs in the perinuclear region. Using cholesterol depletion, pharmacological inhibitors, RNA interference, and dominant-negative mutants, we define the mechanisms involved in perinuclear accumulation of PKCα and identify the non-proteasomal mechanism mediating its degradation. We show that intracellular accumulation of PKCα involves at least two clathrin-independent, cholesterol/lipid raft-mediated pathways that do not require ubiquitination of the protein; one is dynamin-dependent and likely involves caveolae, whereas the other is dynamin- and small GTPase-independent. Internalized PKCα traffics through endosomes and is delivered to the lysosome for degradation. Supportive evidence includes (a) detection of the enzyme in EEA1-positive early endosomes, Rab7-positive late endosomes/multivesicular bodies, and LAMP1-positive lysosomes and (b) inhibition of its down-regulation by lysosome-disrupting agents and leupeptin. Only limited dephosphorylation of PKCα occurs during trafficking, with fully mature enzyme being the main target for lysosomal degradation. These studies define a novel and widespread mechanism of desensitization of PKCα signaling that involves endocytic trafficking and lysosome-mediated degradation of the mature, fully phosphorylated protein.
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Affiliation(s)
- Michelle A Lum
- The Eppley Institute, University of Nebraska Medical Center, Omaha, Nebraska 68198-5950, USA
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Tomar N, De RK. Modeling host-pathogen interactions: H. sapiens as a host and C. difficile as a pathogen. J Mol Recognit 2012; 25:474-85. [DOI: 10.1002/jmr.2211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Namrata Tomar
- Machine Intelligence Unit; Indian Statistical Institute; 203 B.T. Road; Kolkata; 700108; India
| | - Rajat K. De
- Machine Intelligence Unit; Indian Statistical Institute; 203 B.T. Road; Kolkata; 700108; India
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Choi SJ, Lee MY, Jo H, Lim SS, Jung SH. Preparative isolation and purification of neuroprotective compounds from Rhus verniciflua by high speed counter-current chromatography. Biol Pharm Bull 2012; 35:559-67. [PMID: 22466561 DOI: 10.1248/bpb.35.559] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, extracts from Rhus verniciflua were demonstrated to significantly attenuate the negative effects of hydrogen peroxide (H(2)O(2)) on transformed retinal ganglion cell line (RGC-5 cells), indicating that they may be protective against oxidative stress-induced retinal degeneration. The inclusion of R. verniciflua in the culture was found to both reduce the levels of reactive oxygen species (ROS) present and lessen the up-regulation of apoptotic proteins such as cleaved poly(ADP-ribose) polymerase, cleaved caspase-3, and cleaved caspase-9. Active compounds were also successfully isolated from R. verniciflua using high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (3.5:5:3.5:5, v/v). Using this method, we successfully separated 252.1 mg of fustin at a purity of over 93.09%, 51.2 mg of fisetin at a purity of over 95.45%, 39.7 mg of sulfuretin at a purity of over 95.17%, and 10.7 mg of butein at a purity of over 95.01% from 1.5 g of R. verniciflua extract. The chemical structures of these compounds were elucidated by chemical and spectral analyses. There isolated compounds also significantly attenuated the negative effects of H(2)O(2) on RGC-5 cells. Results therefore suggest that, due to its anti-oxidative and anti-apoptotic effects, R. verniciflua could be used as a lead substance for the treatment of retinal diseases such as glaucoma.
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Affiliation(s)
- Soon Jung Choi
- Functional Food Center, Korea Institute of Science and Technology, Gangneung Institute, Republic of Korea
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Rohrbeck A, Kolbe T, Hagemann S, Genth H, Just I. Distinct biological activities of C3 and ADP-ribosyltransferase-deficient C3-E174Q. FEBS J 2012; 279:2657-71. [DOI: 10.1111/j.1742-4658.2012.08645.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Targosz-Korecka M, Biedron R, Szczygiel AM, Brzezinka G, Szczerbinski J, Zuk A. Stiffness changes of tumor HEp2 cells correlates with the inhibition and release of TRAIL-induced apoptosis pathways. J Mol Recognit 2012; 25:299-308. [DOI: 10.1002/jmr.2192] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | - Rafal Biedron
- Chair of Immunology, Medical College; Jagiellonian University; Czysta 18; 31-121; Krakow; Poland
| | | | - Grzegorz Brzezinka
- Institute of Physics; Jagiellonian University; Reymonta 4; 30-059; Krakow; Poland
| | - Jacek Szczerbinski
- Institute of Physics; Jagiellonian University; Reymonta 4; 30-059; Krakow; Poland
| | - Anna Zuk
- Institute of Physics; Jagiellonian University; Reymonta 4; 30-059; Krakow; Poland
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Takeba Y, Matsumoto N, Watanabe M, Takenoshita-Nakaya S, Ohta Y, Kumai T, Takagi M, Koizumi S, Asakura T, Otsubo T. The Rho kinase inhibitor fasudil is involved in p53-mediated apoptosis in human hepatocellular carcinoma cells. Cancer Chemother Pharmacol 2012; 69:1545-55. [DOI: 10.1007/s00280-012-1862-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Accepted: 03/12/2012] [Indexed: 01/10/2023]
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Pruitt RN, Lacy DB. Toward a structural understanding of Clostridium difficile toxins A and B. Front Cell Infect Microbiol 2012; 2:28. [PMID: 22919620 PMCID: PMC3417631 DOI: 10.3389/fcimb.2012.00028] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 02/27/2012] [Indexed: 12/17/2022] Open
Abstract
Clostridium difficile is a toxin-producing bacterium that is a frequent cause of hospital-acquired and antibiotic-associated diarrhea. The incidence, severity, and costs associated with C. difficile associated disease are substantial and increasing, making C. difficile a significant public health concern. The two primary toxins, TcdA and TcdB, disrupt host cell function by inactivating small GTPases that regulate the actin cytoskeleton. This review will discuss the role of these two toxins in pathogenesis and the structural and molecular mechanisms by which they intoxicate cells. A focus will be placed on recent publications highlighting mechanistic similarities and differences between TcdA, TcdB, and different TcdB variants.
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Affiliation(s)
- Rory N Pruitt
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville TN, USA
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Ludwig K, Parsons SJ. The Tumor Suppressor, p190RhoGAP, Differentially Initiates Apoptosis and Confers Docetaxel Sensitivity to Breast Cancer Cells. Genes Cancer 2011; 2:20-30. [PMID: 21779478 DOI: 10.1177/1947601911402680] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 02/03/2011] [Accepted: 02/11/2011] [Indexed: 12/22/2022] Open
Abstract
p190RhoGAP (p190) is a negative regulator of RhoGTPases and a putative tumor suppressor, whose mechanism of tumor suppression is poorly defined. Ectopic expression of p190 induces various morphological phenotypes, including multinucleation, dendrite-like formation, and chromatin condensation, suggesting an involvement in apoptosis. We examined the possibility that p190 can function as a tumor suppressor by regulating induction of apoptosis. We show that the predominant phenotype of p190 overexpression in a variety of cell lines is apoptosis, which is mediated through p190's regulation of Rho and caspases. The secondary phenotypes, multinucleation and dendrite-like formation, are determined by transformation status, not cell lineage, and appear to be intermediate phenotypes in the p190-induced apoptotic pathway. Finally, we show that p190 levels can regulate the apoptotic response of breast cancer cell lines to docetaxel through its regulation of Rho. Together, these findings suggest that one mechanism by which p190 can mediate its tumor-suppressive function is through regulation of Rho-activated cell death pathways and that this function can be exploited to optimize the action of cytoskeletal-based chemotherapeutics, such as the taxanes.
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Affiliation(s)
- Kirsten Ludwig
- Department of Microbiology and Cancer Center, University of Virginia Health System, Charlottesville, VA, USA
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Jha HC, Srivastava P, Vardhan H, Singh LC, Bhengraj AR, Prasad J, Mittal A. Chlamydia pneumoniae heat shock protein 60 is associated with apoptotic signaling pathway in human atheromatous plaques of coronary artery disease patients. J Cardiol 2011; 58:216-25. [PMID: 21889313 DOI: 10.1016/j.jjcc.2011.07.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 07/22/2011] [Accepted: 07/23/2011] [Indexed: 12/11/2022]
Abstract
BACKGROUND Chlamydia pneumoniae heat shock protein (HSP) 60 is known to contribute to the activation of inflammation. In addition, there are contradictory reports on C. pneumoniae and their role in activation of pathways (apoptotic/antiapoptotic/necrosis) in coronary artery disease (CAD). Hence, more studies are required to know the actual role of C. pneumoniae in activation of apoptotic/antiapoptotic/necrosis pathways. METHODS AND RESULTS In this study, two sets of patient groups (cHSP60 positive and cHSP60 negative) were included and gene expression was studied by cDNA micro array and real time polymerase chain reaction arrays. Expression of Caspase-3, 8, 9, c-FLIP, PPAR-γ, PGC-1α, and Gsk-3b were also evaluated at protein level by immunoblotting. In cHSP60 positive CAD patients significantly higher (p<0.001) mRNA expression was found for CCL4, CXCL4, CXCL9, IL-8, CD40LG, CD8, TGFβ1, TGFβ2, APOE, EGR1, CTGF, APOB, LDLR, LPA, and LPL, whereas significantly lower (p<0.001) mRNA expression was detected for CD4, IL1F10, IFNA2, and IL-10 as compared to cHSP60 negative CAD patients. Additionally, at protein level expression of Caspase-3 (p=0.027), 8 (p=0.028), and 9 (p=0.037) were higher and c-FLIP (p=0.028) and PPAR-γ (p=0.95) expression were comparable in cHSP60 positive CAD patients compared to cHSP60 negative CAD patients. CONCLUSION Genes/proteins of pre-apoptotic caspase dependent/independent pathways, chemokines, and inflammatory cytokines receptors were significantly up-regulated in human atheromatous plaques of cHSP60 positive CAD patients suggesting an association of cHSP60 with CAD.
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Affiliation(s)
- Hem Chandra Jha
- Institute of Pathology (ICMR), Safdarjung Hospital Campus, Post Box No. 4909, New Delhi 110 029, India
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Lu Q, Rounds S. Focal adhesion kinase and endothelial cell apoptosis. Microvasc Res 2011; 83:56-63. [PMID: 21624380 DOI: 10.1016/j.mvr.2011.05.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 05/10/2011] [Accepted: 05/12/2011] [Indexed: 10/18/2022]
Abstract
Focal adhesion kinase (FAK) is a key component of cell-substratum adhesions, known as focal adhesion complexes. Growing evidence indicates that FAK is important in maintenance of normal cell survival and that disruption of FAK signaling results in loss of substrate adhesion and anoikis (apoptosis) of anchorage-dependent cells, such as endothelial cells. Basal FAK activity in non-stimulated endothelial cells is important in maintaining cell adhesion to integrins via PI3 kinase/Akt signaling. FAK activity is dependent upon small GTPase signaling. FAK also appears to be important in cardiomyocyte hypertrophy and hypoxia/reoxygenation-induced cell death. This review summarizes the signaling pathways of FAK in prevention of apoptosis and the role of FAK in mediating adenosine and homocysteine-induced endothelial cell apoptosis and in cardiovascular diseases.
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Affiliation(s)
- Qing Lu
- Vascular Research Laboratory, Providence Veterans Affairs Medical Center, Department of Medicine, Alpert Medical School of Brown University, Providence, RI 02908, USA
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Primary human colonic myofibroblasts are resistant to Clostridium difficile toxin A-induced, but not toxin B-induced, cell death. Infect Immun 2011; 79:1623-30. [PMID: 21245273 DOI: 10.1128/iai.00686-10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Colonic inflammation in Clostridium difficile infection is mediated by released toxins A and B. We investigated responses to C. difficile toxins A and B by isolated primary human colonic myofibroblasts, which represent a distinct subpopulation of mucosal cells that are normally located below the intestinal epithelium. Following incubation with either purified toxin A or B, there was a change in myofibroblast morphology to stellate cells with processes that were immunoreactive for alpha-smooth muscle actin. Most of the myofibroblasts remained viable, with persistence of stellate morphology, despite exposure to high concentrations (up to 10 μg/ml) of toxin A for 72 h. In contrast, a majority of the toxin B-exposed myofibroblasts lost their processes prior to cell death over 24 to 72 h. At low concentrations, toxin A provided protection against toxin B-induced cell death. Within 4 h, myofibroblasts exposed to either toxin A or toxin B lost expression of the nonglucosylated form of Rac1, and there was also a loss of the active form of RhoA. Despite preexposure to high concentrations of toxin A for 3 h, colonic myofibroblasts were able to recover their morphology and proliferative capacity during prolonged culture in medium. However, toxin B-preexposed myofibroblasts were not able to recover. In conclusion, primary human colonic mucosal myofibroblasts are resistant to toxin A (but not toxin B)-induced cell death. Responses by colonic myofibroblasts may play an important role in mucosal protection, repair, and regeneration in colitis due to C. difficile infection.
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Difference in the biological effects of Clostridium difficile toxin B in proliferating and non-proliferating cells. Naunyn Schmiedebergs Arch Pharmacol 2011; 383:275-83. [PMID: 21212934 DOI: 10.1007/s00210-010-0595-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 12/21/2010] [Indexed: 02/07/2023]
Abstract
Toxin A (TcdA) and toxin B (TcdB) from Clostridium difficile are the causative agents of the C. difficile-associated diarrhea (CDAD) and its severe form, the pseudomembranous colitis. TcdA and TcdB both glucosylate and thereby inactivate low molecular weight GTP-binding proteins of the Rho, Rac, and Cdc42 subfamilies. In cultured cell lines, TcdB induces actin re-organization and bi-nucleation ("cytopathic effects") and cell death ("cytotoxic effects"). In this study, the role of cell cycle progression in the cytopathic and the cytotoxic effects of TcdB is evaluated by a differential analysis of these effects in proliferating and non-proliferating cells. Density-synchronized murine fibroblasts and confluent HT29 colonocytes are exploited as cell culture models for non-proliferating cells. Cell death is analyzed in terms of a loss of cell viability, phosphatidylserine exposure, and DNA fragmentation. In proliferating cells, TcdB blocks cell proliferation and induces apoptotic cell death. In contrast, TcdB induces non-apoptotic cell death in non-proliferating cells. TcdB-induced cell rounding turns out to be independent of cell cycle progression. Cell cycle progression is an important determinant in the biological effects of TcdB. With respect to the pathology of CDAD, this study leads to the new hypothesis that necrotic cell death of terminally differentiated colonocytes and inhibition of epithelial renewal of the colon contribute to the pathogenesis of CDAD.
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Tagami M, Kusuhara S, Imai H, Uemura A, Honda S, Tsukahara Y, Negi A. MRP4 knockdown enhances migration, suppresses apoptosis, and produces aggregated morphology in human retinal vascular endothelial cells. Biochem Biophys Res Commun 2010; 400:593-8. [DOI: 10.1016/j.bbrc.2010.08.109] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 08/25/2010] [Indexed: 01/04/2023]
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Jung SH, Kim BJ, Lee EH, Osborne NN. Isoquercitrin is the most effective antioxidant in the plant Thuja orientalis and able to counteract oxidative-induced damage to a transformed cell line (RGC-5 cells). Neurochem Int 2010; 57:713-21. [PMID: 20708054 DOI: 10.1016/j.neuint.2010.08.005] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 07/29/2010] [Accepted: 08/03/2010] [Indexed: 02/06/2023]
Abstract
The shrub Thuja orientalis is extensively used as a herbal medicine in Korea and China. In the present study extracts of the plant were subjected to fractionation and purification, with seven compounds (myricitrin, isoquercitrin, hypoletin-7-O-β-D-xylopyranoside, quercitrin, kaempferin, kaempferol, and amentoflavone) being isolated. Of these seven compounds, isoquercitrin was found to be the most effective at attenuating the death of RGC-5 cells in culture caused by exposure to hydrogen peroxide (H(2)O(2)). It was found that an insult of H(2)O(2) to RGC-5 cells caused them to die by apoptosis, demonstrated not only by staining dead cells for phosphatidylserine but also by the up-regulation (cleaved PARP, AIF, p53) and down-regulation (Bcl-2) of proteins associated with apoptosis and survival. Subsequent studies showed that isoquercitrin acts as a powerful antioxidant. It scavenges ROS generally as demonstrated by staining of cultures as well as the generation of individual radical species (H(2)O(2), OH* and O(2)(*-)). Moreover, isoquercitrin reduced the depletion of glutathione (GSH) caused by elevation of specific radical species (H(2)O(2), OH* and O(2)(*-)) in RGC-5 cells in culture and blunted the decrease in catalase and glutathione peroxidase 1 (Gpx-1) caused by exposure of RGC-5 cells to H(2)O(2). Furthermore, isoquercitrin potently attenuated the lipid peroxidation of rat brain homogenates initiated by nitric oxide, with an IC(50) value of 1.04 μM. Since isoquercitrin can be tolerated when taken orally it is suggested that this substance might reach the retina and therefore be potentially useful for treating glaucoma, in which oxidative stress is thought to play a major role in the demise of retinal ganglion cells.
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Affiliation(s)
- Sang Hoon Jung
- Nuffield Laboratory of Ophthalmology, Oxford University, John Radcliffe Hospital, Oxford, UK
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Inhibition of Rho-ROCK signaling induces apoptotic and non-apoptotic PS exposure in cardiomyocytes via inhibition of flippase. J Mol Cell Cardiol 2010; 49:781-90. [PMID: 20691698 DOI: 10.1016/j.yjmcc.2010.07.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 07/12/2010] [Accepted: 07/28/2010] [Indexed: 02/06/2023]
Abstract
Subsequent to myocardial infarction, cardiomyocytes within the infarcted areas and border zones expose phosphatidylserine (PS) in the outer plasma membrane leaflet (flip-flop). We showed earlier that in addition to apoptosis, this flip-flop can be reversible in cardiomyocytes. We now investigated a possible role for Rho and downstream effector Rho-associated kinase (ROCK) in the process of (reversible) PS exposure and apoptosis in cardiomyocytes. In rat cardiomyoblasts (H9c2 cells) and isolated adult ventricular rat cardiomyocytes Clostridium difficile Toxin B (TcdB), a Rho GTPase family inhibitor, C3 transferase (C3), a Rho(A,B,C) inhibitor and the ROCK inhibitors Y27632 and H1152 were used to inhibit Rho-ROCK signaling. PS exposure was assessed via flow cytometry and fluorescent digital imaging microscopy using annexin V. Akt expression and phosphorylation were analyzed via Western blot, and Akt activity was inhibited by wortmannin. The cellular concentration activated caspase 3 was determined as a measure of apoptosis, and flippase activity was assessed via flow cytometry using NBD-labeled PS. TcdB, C3, Y27632 and H1152 all significantly increased PS exposure. TcdB, Y27632 and H1152 all significantly inhibited phosphorylation of the anti-apoptotic protein Akt and Akt inhibition by wortmannin lead to increased PS exposure. However, only TcdB and C3, but not ROCK- or Akt inhibition led to caspase 3 activation and thus apoptosis. Notably, pancaspase inhibitor zVAD only partially inhibited TcdB-induced PS exposure indicating the existence of apoptotic and non-apoptotic PS exposure. The induced PS exposure coincided with decreased flippase activity as measured with NBD-labeled PS flip-flop. In this study, we show a regulatory role for a novel signaling route, Rho-ROCK-flippase signaling, in maintaining asymmetrical membrane phospholipid distribution in cardiomyocytes.
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Sun X, Savidge T, Feng H. The enterotoxicity of Clostridium difficile toxins. Toxins (Basel) 2010; 2:1848-80. [PMID: 22069662 PMCID: PMC3153265 DOI: 10.3390/toxins2071848] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 06/23/2010] [Accepted: 07/09/2010] [Indexed: 02/06/2023] Open
Abstract
The major virulence factors of Clostridium difficile infection (CDI) are two large exotoxins A (TcdA) and B (TcdB). However, our understanding of the specific roles of these toxins in CDI is still evolving. It is now accepted that both toxins are enterotoxic and proinflammatory in the human intestine. Both purified TcdA and TcdB are capable of inducing the pathophysiology of CDI, although most studies have focused on TcdA. C. difficile toxins exert a wide array of biological activities by acting directly on intestinal epithelial cells. Alternatively, the toxins may target immune cells and neurons once the intestinal epithelial barrier is disrupted. The toxins may also act indirectly by stimulating cells to produce chemokines, proinflammatory cytokines, neuropeptides and other neuroimmune signals. This review considers the mechanisms of TcdA- and TcdB-induced enterotoxicity, and recent developments in this field.
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Affiliation(s)
- Xingmin Sun
- Tufts Cummings School of Veterinary Medicine, North Grafton, MA, 01536, USA;
| | - Tor Savidge
- The University of Texas Medical Branch, Galveston, TX, 77555, USA;
| | - Hanping Feng
- Tufts Cummings School of Veterinary Medicine, North Grafton, MA, 01536, USA;
- Author to whom correspondence should be addressed; ; Tel.: +1-508-887-4252; Fax: +1-508-839-7911
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