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Choi Y, Lichterman JN, Coughlin LA, Poulides N, Li W, Del Valle P, Palmer SN, Gan S, Kim J, Zhan X, Gao Y, Evers BM, Hooper LV, Pasare C, Koh AY. Immune checkpoint blockade induces gut microbiota translocation that augments extraintestinal antitumor immunity. Sci Immunol 2023; 8:eabo2003. [PMID: 36867675 PMCID: PMC10080670 DOI: 10.1126/sciimmunol.abo2003] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 02/09/2023] [Indexed: 03/05/2023]
Abstract
Gut microbiota, specifically gut bacteria, are critical for effective immune checkpoint blockade therapy (ICT) for cancer. The mechanisms by which gut microbiota augment extraintestinal anticancer immune responses, however, are largely unknown. Here, we find that ICT induces the translocation of specific endogenous gut bacteria into secondary lymphoid organs and subcutaneous melanoma tumors. Mechanistically, ICT induces lymph node remodeling and dendritic cell (DC) activation, which facilitates the translocation of a selective subset of gut bacteria to extraintestinal tissues to promote optimal antitumor T cell responses in both the tumor-draining lymph nodes (TDLNs) and the primary tumor. Antibiotic treatment results in decreased gut microbiota translocation into mesenteric lymph nodes (MLNs) and TDLNs, diminished DC and effector CD8+ T cell responses, and attenuated responses to ICT. Our findings illuminate a key mechanism by which gut microbiota promote extraintestinal anticancer immunity.
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Affiliation(s)
- Yongbin Choi
- Department of Pediatrics, Division of Hematology/Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jake N. Lichterman
- Division of Hematology/Oncology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Laura A. Coughlin
- Department of Pediatrics, Division of Hematology/Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Nicole Poulides
- Department of Pediatrics, Division of Hematology/Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Wenling Li
- Department of Pediatrics, Division of Hematology/Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Priscilla Del Valle
- Department of Pediatrics, Division of Hematology/Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Cell and Molecular Biology, The University of Texas Southwestern Medical Center, Dallas, TX. 75390
| | - Suzette N. Palmer
- Department of Pediatrics, Division of Hematology/Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Population and Data Sciences, The University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Biomedical Engineering, The University of Texas Southwestern Medical, Dallas, TX 75390
| | - Shuheng Gan
- Department of Population and Data Sciences, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jiwoong Kim
- Department of Population and Data Sciences, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Xiaowei Zhan
- Department of Population and Data Sciences, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Yajing Gao
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Bret M. Evers
- Department of Pathology, The University of Texas Southwestern Medical, Dallas, TX 75390
| | - Lora V. Hooper
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
- The Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Chandrashekhar Pasare
- Division of Immunobiology and Center for Inflammation and Tolerance, Cincinnati Children’s Hospital Medical Center Cincinnati, OH 45229
- Department of Pediatrics, University of Cincinnati, College of Medicine, Cincinnati, OH 45220
| | - Andrew Y. Koh
- Department of Pediatrics, Division of Hematology/Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
- Harold C. Simmons Comprehensive Cancer Center, The University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Microbiology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
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Gao Y, Deason K, Jain A, Irizarry-Caro RA, Dozmorov I, Coughlin LA, Rauch I, Evers BM, Koh AY, Wakeland EK, Pasare C. Transcriptional profiling identifies caspase-1 as a T cell-intrinsic regulator of Th17 differentiation. J Exp Med 2020; 217:133631. [PMID: 31967646 PMCID: PMC7144520 DOI: 10.1084/jem.20190476] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 10/07/2019] [Accepted: 12/09/2019] [Indexed: 12/27/2022] Open
Abstract
Dendritic cells (DCs) are critical for the differentiation of pathogen-specific CD4 T cells. However, to what extent innate cues from DCs dictate transcriptional changes in T cells remains elusive. Here, we used DCs stimulated with specific pathogens to prime CD4 T cells in vitro and found that these T cells express unique transcriptional profiles dictated by the nature of the priming pathogen. More specifically, the transcriptome of in vitro C. rodentium–primed Th17 cells resembled that of Th17 cells primed following infection in vivo but was remarkably distinct from cytokine-polarized Th17 cells. We identified caspase-1 as a unique gene up-regulated only in pathogen-primed Th17 cells and discovered a critical role for T cell–intrinsic caspase-1, independent of inflammasome, in optimal priming of Th17 responses. T cells lacking caspase-1 failed to induce colitis or confer protection against C. rodentium infection due to suboptimal Th17 cell differentiation in vivo. This study underlines the importance of DC-mediated priming in identifying novel regulators of T cell differentiation.
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Affiliation(s)
- Yajing Gao
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX.,Immunology Graduate Program, University of Texas Southwestern Medical Center, Dallas, TX
| | - Krystin Deason
- Immunology Graduate Program, University of Texas Southwestern Medical Center, Dallas, TX
| | - Aakanksha Jain
- Division of Immunobiology, Center for Inflammation and Tolerance, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.,Immunology Graduate Program, University of Texas Southwestern Medical Center, Dallas, TX
| | - Ricardo A Irizarry-Caro
- Division of Immunobiology, Center for Inflammation and Tolerance, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.,Immunology Graduate Program, University of Texas Southwestern Medical Center, Dallas, TX
| | - Igor Dozmorov
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Laura A Coughlin
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Isabella Rauch
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR
| | - Bret M Evers
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Andrew Y Koh
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX.,Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX.,Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Edward K Wakeland
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Chandrashekhar Pasare
- Division of Immunobiology, Center for Inflammation and Tolerance, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
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3
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Piper HG, Coughlin LA, Hussain S, Nguyen V, Channabasappa N, Koh AY. The Impact of Lactobacillus Probiotics on the Gut Microbiota in Children With Short Bowel Syndrome. J Surg Res 2020; 251:112-118. [DOI: 10.1016/j.jss.2020.01.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 01/22/2020] [Accepted: 01/31/2020] [Indexed: 12/22/2022]
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Piper HG, Coughlin LA, Nguyen V, Channabasappa N, Koh AY. A comparison of small bowel and fecal microbiota in children with short bowel syndrome. J Pediatr Surg 2020; 55:878-882. [PMID: 32063370 DOI: 10.1016/j.jpedsurg.2020.01.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 01/25/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Babies with short bowel syndrome (SBS) have small intestinal microbial disturbances that impact gut function. Characterizing the small bowel microbiota is challenging, and the utility of sampling stool is unclear. This study compares the microbiota from fecal samples and the small bowel. METHODS Stool samples were collected (2016-2017) from infants with SBS and colon in continuity (COLON) or SBS with small bowel ostomy (sbSTOMA). The abundance and quantity of major bacterial genera was compared between groups and to healthy controls using 16S rRNA sequencing and qPCR. Kruskall-Wallis test was used for analysis with P values <0.05 considered significant. RESULTS Samples (n = 41) were collected from 15 SBS infants (<2 years) (9 sbSTOMA, 6 COLON) and 3 healthy infants. Demographics and small intestinal length did not differ between sbSTOMA and COLON infants. The microbiota of SBS groups differed significantly from healthy controls. Fecal samples contained higher quantities of bacteria, but there were no significant differences between sbSTOMA and COLON groups in the abundance of facultative or obligate anaerobes, anti-inflammatory Clostridia, Enterobacteriaceae, or Bifidobacterium. CONCLUSION Infants with SBS have disturbances to their intestinal microbiota. Sampling small intestinal effluent is challenging. Stool samples may provide a window into the more proximal microbial community. TYPE OF STUDY Diagnostic. LEVEL OF EVIDENCE Level II.
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Affiliation(s)
- Hannah G Piper
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada.
| | - Laura A Coughlin
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Van Nguyen
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Nandini Channabasappa
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Andrew Y Koh
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA; Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Frankel AE, Froehlich TW, Kim J, Coughlin LA, Xie Y, Frenkel EP, Koh AY. Metagenomic shotgun sequencing to identify specific human gut microbes associated with immune checkpoint therapy efficacy in melanoma patients. J Clin Oncol 2017. [DOI: 10.1200/jco.2017.35.15_suppl.9516] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
9516 Background: Immune checkpoint inhibitor therapy, ICT, achieves durable remissions in 30-50% of patients (pts) with metastatic melanoma (Larkin et al. NEJM 2015). It is still unclear what host factors modulate response to ICT. Preclinical mouse studies with B16 melanoma demonstrated that ICT response was dependent on the presence of specific commensal gut bacteria (Vetizou et al. Science 2015; Sivan et al. Science2015). These specific gut bacteria induced the maturation of dendritic cells (DCs) and T-cells needed for effective ICT. We sought to determine whether specific gut microbiota are associated with improved response to ICT in melanoma patients. Methods: 37 melanoma pts treated with ICT (nivolumab plus ipilimumab or pembrolizumab alone) at UTSW Medical Center were enrolled. Fecal samples were collected prior to ICT. Genomic DNA was extracted, and metagenomic shotgun sequencing (MSS) performed on an Illumina HiSeq 2500 PE-100. Taxonomic (MetaPhlAn) and functional (HUMAnN) analysis was performed on MSS data. Disease status was assessed by CT scans and physical exams every two months. Results: Among the 23 evaluable pts, 8 were classified as RECIST responders, 5 with stable disease and 10 with progression. RECIST responder microbiomes were significantly enriched with Methanobrevibacter smithii(p = 0.03; LDA coupled with effect size measurements, LEfSe; Kruskal-Wallis test) , Bacteroides thetaiotamicron(p = 0.03) , Lactobacillus plantarum(p = 0.04), and Eubacterium limosum(p = 0.01) compared to those with progressive disease. Conclusions: MSS identified 4 specific gut microbiota associated with improved response to ICT therapy in melanoma pts. All of these bacteria have been shown to modulate host immune response (Bang PLoS One 2014; Hickey Cell Host Microbe 2016; Rigaux Allergy 2009; Kaunachi World J Gastroentertol 2006). To gain mechanistic insight and confirm causality, shotgun metabolomics on the same fecal specimens used for MSS, in vitroimmune cell assays using the gut microbiota identified, and preclinical modeling in a mouse melanoma model with ICT are underway. These studies may lay the foundation for optimizing the host response to ICT.
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Affiliation(s)
| | | | - Jiwoong Kim
- The University of Texas Southwestern Medical Center, Dallas, TX
| | | | - Yang Xie
- The University of Texas Southwestern Medical Center, Dallas, TX
| | | | - Andrew Y. Koh
- The University of Texas Southwestern Medical Center, Dallas, TX
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6
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Simms-Waldrip TR, Sunkersett G, Coughlin LA, Savani MR, Arana C, Kim J, Kim M, Zhan X, Greenberg DE, Xie Y, Davies SM, Koh AY. Antibiotic-Induced Depletion of Anti-inflammatory Clostridia Is Associated with the Development of Graft-versus-Host Disease in Pediatric Stem Cell Transplantation Patients. Biol Blood Marrow Transplant 2017; 23:820-829. [PMID: 28192251 DOI: 10.1016/j.bbmt.2017.02.004] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 02/06/2017] [Indexed: 12/11/2022]
Abstract
Adult stem cell transplantation (SCT) patients with graft-versus-host-disease (GVHD) exhibit significant disruptions in gut microbial communities. These changes are associated with higher overall mortality and appear to be driven by specific antibiotic therapies. It is unclear whether pediatric SCT patients who develop GVHD exhibit similar antibiotic-induced gut microbiota community changes. Here, we show that pediatric SCT patients (from Children's Medical Center Dallas, n = 8, and Cincinnati Children's Hospital, n = 7) who developed GVHD showed a significant decline, up to 10-log fold, in gut anti-inflammatory Clostridia (AIC) compared with those without GVHD. In fact, the development of GVHD is significantly associated with this AIC decline and with cumulative antibiotic exposure, particularly antibiotics effective against anaerobic bacteria (P = .003, Firth logistic regression analysis). Using metagenomic shotgun sequencing analysis, we were able to identify specific commensal bacterial species, including AIC, that were significantly depleted in GVHD patients. We then used a preclinical GVHD model to verify our clinical observations. Clindamycin depleted AIC and exacerbated GVHD in mice, whereas oral AIC supplementation increased gut AIC levels and mitigated GVHD in mice. Together, these data suggest that an antibiotic-induced AIC depletion in the gut microbiota is associated with the development of GVHD in pediatric SCT patients.
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Affiliation(s)
| | - Gauri Sunkersett
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Laura A Coughlin
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Milan R Savani
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Carlos Arana
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jiwoong Kim
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas; Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Minsoo Kim
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas; Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Xiaowei Zhan
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas; Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, Texas; Center for Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, Texas
| | - David E Greenberg
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Yang Xie
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas; Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, Texas; Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Stella M Davies
- Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children's Hospital, Cincinnati, Ohio
| | - Andrew Y Koh
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas; Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas.
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7
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Piper HG, Fan D, Coughlin LA, Ho EX, McDaniel MM, Channabasappa N, Kim J, Kim M, Zhan X, Xie Y, Koh AY. Severe Gut Microbiota Dysbiosis Is Associated With Poor Growth in Patients With Short Bowel Syndrome. JPEN J Parenter Enteral Nutr 2016; 41:1202-1212. [PMID: 27406942 DOI: 10.1177/0148607116658762] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Children with short bowel syndrome (SBS) can vary significantly in their growth trajectory. Recent data have shown that children with SBS possess a unique gut microbiota signature compared with healthy controls. We hypothesized that children with SBS and poor growth would exhibit more severe gut microbiota dysbiosis compared with those with SBS who are growing adequately, despite similar intestinal anatomy. MATERIALS AND METHODS Stool samples were collected from children with SBS (n = 8) and healthy controls (n = 3) over 3 months. Gut microbiota populations (16S ribosomal RNA sequencing and metagenomic shotgun sequencing) were compared, including a more in-depth analysis of SBS children exhibiting poor and good growth. Statistical analysis was performed using Mann-Whitney, Kruskal-Wallis, and χ2 tests as appropriate. RESULTS Children with SBS had a significant deficiency of the commensal Firmicutes order Clostridiales ( P = .025, Kruskal-Wallis) compared with healthy children. Furthermore, children with SBS and poor growth were deficient in beneficial bacteria known to produce short-chain fatty acids and had expansion of proinflammatory Enterobacteriaceae ( P = .038, Kruskal-Wallis) compared with children with SBS who were growing adequately. Using metabolic function analyses, SBS/poor growth microbiomes were deficient in genes needed for gluconeogenesis but enriched in branched and aromatic amino acid synthesis and citrate cycle pathway genes. CONCLUSIONS Patients with SBS, particularly those with suboptimal growth, have a marked gut dysbiosis characterized by a paucity of beneficial commensal anaerobes, resulting in a deficiency of key metabolic enzymes found in the gut microbiomes of healthy children.
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Affiliation(s)
- Hannah G Piper
- 1 Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Di Fan
- 2 Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Laura A Coughlin
- 2 Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Evi X Ho
- 2 Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Margaret M McDaniel
- 3 Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Nandini Channabasappa
- 2 Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jiwoong Kim
- 4 Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,5 Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Minsoo Kim
- 4 Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,5 Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Xiaowei Zhan
- 4 Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,5 Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,6 Center for Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Yang Xie
- 4 Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,5 Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,7 Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Andrew Y Koh
- 1 Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,7 Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,8 Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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8
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Lopez-Medina E, Fan D, Coughlin LA, Ho EX, Lamont IL, Reimmann C, Hooper LV, Koh AY. Candida albicans Inhibits Pseudomonas aeruginosa Virulence through Suppression of Pyochelin and Pyoverdine Biosynthesis. PLoS Pathog 2015; 11:e1005129. [PMID: 26313907 PMCID: PMC4552174 DOI: 10.1371/journal.ppat.1005129] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 08/04/2015] [Indexed: 01/09/2023] Open
Abstract
Bacterial-fungal interactions have important physiologic and medical ramifications, but the mechanisms of these interactions are poorly understood. The gut is host to trillions of microorganisms, and bacterial-fungal interactions are likely to be important. Using a neutropenic mouse model of microbial gastrointestinal colonization and dissemination, we show that the fungus Candida albicans inhibits the virulence of the bacterium Pseudomonas aeruginosa by inhibiting P. aeruginosa pyochelin and pyoverdine gene expression, which plays a critical role in iron acquisition and virulence. Accordingly, deletion of both P. aeruginosa pyochelin and pyoverdine genes attenuates P. aeruginosa virulence. Heat-killed C. albicans has no effect on P. aeruginosa, whereas C. albicans secreted proteins directly suppress P. aeruginosa pyoverdine and pyochelin expression and inhibit P. aeruginosa virulence in mice. Interestingly, suppression or deletion of pyochelin and pyoverdine genes has no effect on P. aeruginosa’s ability to colonize the GI tract but does decrease P. aeruginosa’s cytotoxic effect on cultured colonocytes. Finally, oral iron supplementation restores P. aeruginosa virulence in P. aeruginosa and C. albicans colonized mice. Together, our findings provide insight into how a bacterial-fungal interaction can modulate bacterial virulence in the intestine. Previously described bacterial-fungal antagonistic interactions have focused on growth inhibition or colonization inhibition/modulation, yet here we describe a novel observation of fungal-inhibition of bacterial effectors critical for virulence but not important for colonization. These findings validate the use of a mammalian model system to explore the complexities of polymicrobial, polykingdom infections in order to identify new therapeutic targets for preventing microbial disease. Pseudomonas aeruginosa and Candida albicans are two medically important human pathogens that often co-infect or co-colonize the same human niches, such as the gut. In a normal healthy host, P. aeruginosa and C. albicans can colonize the gut without any significant pathologic sequelae. But in immunocompromised hosts, both pathogens can escape the gut and cause life-threatening disseminated infections. Yet the mechanisms and pathogenic consequences of interactions between these two pathogens within a living mammalian host are not well understood. Here, we use a mouse model of P. aeruginosa and C. albicans gut co-infection to better understand the mechanisms by which C. albicans inhibits P. aeruginosa infection. C. albicans inhibits the expression of P. aeruginosa genes that are vital for iron acquisition. Accordingly, deleting these iron acquisition genes in P. aeruginosa prevents infection. Understanding how microbes interact and antagonize each other may help us identify new potential therapeutic targets for preventing or treating infections.
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Affiliation(s)
- Eduardo Lopez-Medina
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Di Fan
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Laura A. Coughlin
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Evi X. Ho
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Iain L. Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Cornelia Reimmann
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Lora V. Hooper
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- The Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Center for Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Andrew Y. Koh
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- * E-mail:
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9
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Tabashnik BE, Fabrick JA, Henderson S, Biggs RW, Yafuso CM, Nyboer ME, Manhardt NM, Coughlin LA, Sollome J, Carrière Y, Dennehy TJ, Morin S. DNA screening reveals pink bollworm resistance to Bt cotton remains rare after a decade of exposure. J Econ Entomol 2006; 99:1525-30. [PMID: 17066779 DOI: 10.1603/0022-0493-99.5.1525] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Transgenic crops producing toxins from the bacterium Bacillus thuringiensis (Bt) kill insect pests and can reduce reliance on insecticide sprays. Although Bt cotton (Gossypium hirsutum L.) and Bt corn (Zea mays L.) covered 26 million ha worldwide in 2005, their success could be cut short by evolution of pest resistance. Monitoring the early phases of pest resistance to Bt crops is crucial, but it has been extremely difficult because bioassays usually cannot detect heterozygotes harboring one allele for resistance. We report here monitoring of resistance to Bt cotton with DNA-based screening, which detects single resistance alleles in heterozygotes. We used polymerase chain reaction primers that specifically amplify three mutant alleles of a cadherin gene linked with resistance to Bt cotton in pink bollworm, Pectinophora gossypiella (Saunders), a major pest. We screened DNA of 5,571 insects derived from 59 cotton fields in Arizona, California, and Texas during 2001-2005. No resistance alleles were detected despite a decade of exposure to Bt cotton. In conjunction with data from bioassays and field efficacy tests, the results reported here contradict predictions of rapid pest resistance to Bt crops.
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Affiliation(s)
- Bruce E Tabashnik
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.
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10
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Tabashnik BE, Fabrick JA, Henderson S, Biggs RW, Yafuso CM, Nyboer ME, Manhardt NM, Coughlin LA, Sollome J, Carrière Y, Dennehy TJ, Morin S. DNA screening reveals pink bollworm resistance to Bt cotton remains rare after a decade of exposure. J Econ Entomol 2006; 99:1525-1530. [PMID: 17066779 DOI: 10.1093/jee/99.5.1525] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Transgenic crops producing toxins from the bacterium Bacillus thuringiensis (Bt) kill insect pests and can reduce reliance on insecticide sprays. Although Bt cotton (Gossypium hirsutum L.) and Bt corn (Zea mays L.) covered 26 million ha worldwide in 2005, their success could be cut short by evolution of pest resistance. Monitoring the early phases of pest resistance to Bt crops is crucial, but it has been extremely difficult because bioassays usually cannot detect heterozygotes harboring one allele for resistance. We report here monitoring of resistance to Bt cotton with DNA-based screening, which detects single resistance alleles in heterozygotes. We used polymerase chain reaction primers that specifically amplify three mutant alleles of a cadherin gene linked with resistance to Bt cotton in pink bollworm, Pectinophora gossypiella (Saunders), a major pest. We screened DNA of 5,571 insects derived from 59 cotton fields in Arizona, California, and Texas during 2001-2005. No resistance alleles were detected despite a decade of exposure to Bt cotton. In conjunction with data from bioassays and field efficacy tests, the results reported here contradict predictions of rapid pest resistance to Bt crops.
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Affiliation(s)
- Bruce E Tabashnik
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.
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