When draining lymph nodes become infected by Yersinia pestis (Y. pestis), a massive influx of phagocytic cells occurs, resulting in distended and necrotic structures known as buboes. The bubonic stage of the Y. pestis life cycle precedes septicemia, which is facilitated by trafficking of infected mononuclear phagocytes through these buboes. However, how Y. pestis convert these immunocytes recruited by host to contain the pathogen into vehicles for bacterial dispersal and the role of immune cell death in this context are unknown. We show that the lymphatic spread requires Yersinia outer protein J (YopJ), which triggers death of infected macrophages by downregulating a suppressor of receptor-interacting protein kinase 1–mediated (RIPK1-mediated) cell death programs. The YopJ-triggered cell death was identified as necroptotic, which released intracellular bacteria, allowing them to infect new neighboring cell targets. Dying macrophages also produced chemotactic sphingosine 1-phosphate, enhancing cell-to-cell contact, further promoting infection. This necroptosis-driven expansion of infected macrophages in buboes maximized the number of bacteria-bearing macrophages reaching secondary lymph nodes, leading to sepsis. In support, necrostatins confined bacteria within macrophages and protected mice from lethal infection. These findings define necrotization of buboes as a mechanism for bacterial spread and a potential target for therapeutic intervention.
Mohammad Arifuzzaman, W.X. Gladys Ang, Hae Woong Choi, Matthew L. Nilles, Ashley L. St. John, Soman N. Abraham
Studies in patients with genetic defects can provide unique insights regarding the role of specific genes and pathways in humans. Patients with defects in the Th17/IL-17 axis, such as patients harboring loss-of-function STAT3 mutations (autosomal-dominant hyper IgE syndrome; AD-HIES) present with recurrent oral fungal infections. Our studies aimed to comprehensively evaluate consequences of STAT3 deficiency on the oral commensal microbiome. We characterized fungal and bacterial communities in AD-HIES in the presence and absence of oral fungal infection compared with healthy volunteers. Analyses of oral mucosal fungal communities in AD-HIES revealed severe dysbiosis with dominance of Candida albicans (C. albicans) in actively infected patients and minimal representation of health-associated fungi and/or opportunists. Bacterial communities also displayed dysbiosis in AD-HIES, particularly in the setting of active Candida infection. Active candidiasis was associated with decreased microbial diversity and enrichment of the streptococci Streptococcus oralis (S. oralis) and S. mutans, suggesting an interkingdom interaction of C. albicans with oral streptococci. Increased abundance of S. mutans was consistent with susceptibility to dental caries in AD-HIES. Collectively, our findings illustrate a critical role for STAT3/Th17 in the containment of C. albicans as a commensal organism and an overall contribution in the establishment of fungal and bacterial oral commensal communities.
Loreto Abusleme, Patricia I. Diaz, Alexandra F. Freeman, Teresa Greenwell-Wild, Laurie Brenchley, Jigar V. Desai, Weng-Ian Ng, Steven M. Holland, Michail S. Lionakis, Julia A. Segre, Heidi H. Kong, Niki M. Moutsopoulos
Obesity is a risk factor for osteoarthritis (OA), the greatest cause of disability in the US. The impact of obesity on OA is driven by systemic inflammation, and increased systemic inflammation is now understood to be caused by gut microbiome dysbiosis. Oligofructose, a nondigestible prebiotic fiber, can restore a lean gut microbial community profile in the context of obesity, suggesting a potentially novel approach to treat the OA of obesity. Here, we report that — compared with the lean murine gut — obesity is associated with loss of beneficial Bifidobacteria, while key proinflammatory species gain in abundance. A downstream systemic inflammatory signature culminates with macrophage migration to the synovium and accelerated knee OA. Oligofructose supplementation restores the lean gut microbiome in obese mice, in part, by supporting key commensal microflora, particularly Bifidobacterium pseudolongum. This is associated with reduced inflammation in the colon, circulation, and knee and protection from OA. This observation of a gut microbiome–OA connection sets the stage for discovery of potentially new OA therapeutics involving strategic manipulation of specific microbial species inhabiting the intestinal space.
Eric M. Schott, Christopher W. Farnsworth, Alex Grier, Jacquelyn A. Lillis, Sarah Soniwala, Gregory H. Dadourian, Richard D. Bell, Madison L. Doolittle, David A. Villani, Hani Awad, John P. Ketz, Fadia Kamal, Cheryl Ackert-Bicknell, John M. Ashton, Steven R. Gill, Robert A. Mooney, Michael J. Zuscik
Adoptive T cell therapy (ACT) is a promising new modality for malignancies. Here, we report that adoptive T cell efficacy in tumor-bearing mice is significantly affected by differences in the native composition of the gut microbiome or treatment with antibiotics, or by heterologous fecal transfer. Depletion of bacteria with vancomycin decreased the rate of tumor growth in mice from The Jackson Laboratory receiving ACT, whereas treatment with neomycin and metronidazole had no effect, indicating the role of specific bacteria in host response. Vancomycin treatment induced an increase in systemic CD8α+ DCs, which sustained systemic adoptively transferred antitumor T cells in an IL-12–dependent manner. In subjects undergoing allogeneic hematopoietic cell transplantation, we found that oral vancomycin also increased IL-12 levels. Collectively, our findings demonstrate an important role played by the gut microbiota in the antitumor effectiveness of ACT and suggest potentially new avenues to improve response to ACT by altering the gut microbiota.
Mireia Uribe-Herranz, Kyle Bittinger, Stavros Rafail, Sonia Guedan, Stefano Pierini, Ceylan Tanes, Alex Ganetsky, Mark A. Morgan, Saar Gill, Janos L. Tanyi, Frederic D. Bushman, Carl H. June, Andrea Facciabene
Malaria eradication necessitates new tools to fight the evolving and complex Plasmodium pathogens. These tools include prophylactic drugs that eliminate Plasmodium liver stages and consequently prevent clinical disease, decrease transmission, and reduce the propensity for resistance development. Currently, the identification of these drugs relies on in vitro P. falciparum liver stage assays or in vivo causal prophylaxis assays using rodent malaria parasites; there is no method to directly test in vivo liver stage activity of candidate antimalarials against the human malaria–causing parasite P. falciparum. Here, we use a liver-chimeric humanized mouse (FRG huHep) to demonstrate in vivo P. falciparum liver stage development and describe the efficacy of clinically used and candidate antimalarials with prophylactic activity. We show that daily administration of atovaquone-proguanil (ATQ-PG; ATQ, 30 mg/kg, and PG, 10 mg/kg) protects 5 of 5 mice from liver stage infection, consistent with the use in humans as a causal prophylactic drug. Single-dose primaquine (60 mg/kg) has similar activity to that observed in humans, demonstrating the activity of this drug (and its active metabolites) in FRG huHep mice. We also show that DSM265, a selective Plasmodial dihydroorotate dehydrogenase inhibitor with causal prophylactic activity in humans, reduces liver stage burden in FRG huHep mice. Finally, we measured liver stage–to–blood stage transition of the parasite, the ultimate readout of prophylactic activity and measurement of infective capacity of parasites in the liver, to show that ATQ-PG reduces blood stage patency to below the limit of quantitation by quantitative PCR (qPCR). The FRG huHep model, thus, provides a platform for preclinical evaluation of drug candidates for liver stage causal prophylactic activity, pharmacokinetic/pharmacodynamics studies, and biological studies to investigate the mechanism of action of liver stage active antimalarials.
Erika L. Flannery, Lander Foquet, Vorada Chuenchob, Matthew Fishbaugher, Zachary Billman, Mary Jane Navarro, William Betz, Tayla M. Olsen, Joshua Lee, Nelly Camargo, Thao Nguyen, Carola Schafer, Brandon K. Sack, Elizabeth M. Wilson, Jessica Saunders, John Bial, Brice Campo, Susan A. Charman, Sean C. Murphy, Margaret A. Phillips, Stefan H.I. Kappe, Sebastian A. Mikolajczak
Initial promising results with immune sera guided early human mAb approaches against Gram-negative sepsis to an LPS neutralization mechanism, but these efforts failed in human clinical trials. Emergence of multidrug resistance has renewed interest in pathogen-specific mAbs. We utilized a pair of antibodies targeting
Taylor S. Cohen, Mark Pelletier, Lily Cheng, Meghan E. Pennini, Jessica Bonnell, Romana Cvitkovic, Chew-shun Chang, Xiaodong Xiao, Elisabetta Cameroni, Davide Corti, Elena Semenova, Paul Warrener, Bret R. Sellman, JoAnn Suzich, Qun Wang, C. Kendall Stover
The placenta is a barrier against maternal-fetal transmission of pathogens. Placental infections can cause several adverse pregnancy outcomes, including preterm birth (PTB). Yet, we have limited knowledge regarding the mechanisms the placenta uses to control infections. Here, we show that autophagy, a cellular recycling pathway important for host defense against pathogens, and the autophagy gene Atg16L1 play a key role in placental defense and are negatively associated with PTB in pregnant women. First, we demonstrate that placentas from women who delivered preterm exhibit reduced autophagy activity and are associated with higher infection indicators. Second, we identify the cellular location of the autophagy activity as being in syncytial trophoblasts. Third, we demonstrate that higher levels of autophagy and ATG16L1 in human trophoblasts were associated with increased resistance to infection. Accordingly, loss of autophagy or ATG16L1 impaired trophoblast antibacterial defenses. Fourth, we show that
Bin Cao, Colin Macones, Indira U. Mysorekar
Catheter-associated urinary tract infections (CAUTI) are the most common hospital-associated infections. Here, we report that bladder catheterization initiated a persistent sterile inflammatory reaction within minutes of catheter implantation. Catheterization resulted in increased expression of genes associated with defense responses and cellular migration, with ensuing rapid and sustained innate immune cell infiltration into the bladder. Catheterization also resulted in hypersensitivity to
Matthieu Rousseau, H.M. Sharon Goh, Sarah Holec, Matthew L. Albert, Rohan B.H. Williams, Molly A. Ingersoll, Kimberly A. Kline
BACKGROUND. Paneth cell dysfunction has been implicated in a subset of Crohn’s disease (CD) patients. We previously stratified clinical outcomes of CD patients by using Paneth cell phenotypes, which we defined by the intracellular distribution of antimicrobial proteins. Animal studies suggest that Paneth cells shape the intestinal microbiome. However, it is unclear whether Paneth cell phenotypes alter the microbiome complexity in CD subjects. Therefore, we analyzed the correlation of Paneth cell phenotypes with mucosal microbiome composition and ileal RNA expression in pediatric CD and noninflammatory bowel disease (non-IBD) patients.
METHODS. Pediatric CD (
RESULTS. The prevalence of abnormal Paneth cells was higher in pediatric versus adult CD cohorts. For pediatric CD patients, those with abnormal Paneth cells showed significant changes in their ileal mucosal microbiome, highlighted by reduced protective microbes and enriched proinflammatory microbes. Ileal transcriptome profiles showed reduced transcripts for genes that control oxidative phosphorylation in CD patients with abnormal Paneth cells. These transcriptional changes in turn were correlated with specific microbiome alterations. In non-IBD patients, a subset contained abnormal Paneth cells. However, this subset was not associated with alterations in the microbiome or host transcriptome.
CONCLUSION. Paneth cell abnormalities in human subjects are associated with mucosal dysbiosis in the context of CD, and these changes are associated with alterations in oxidative phosphorylation, potentially in a feedback loop.
FUNDING. The research was funded by Helmsley Charitable Trust (to T.S. Stappenbeck, R.J. Xavier, and D.P.B. McGovern), Crohn’s and Colitis Foundation of America (to N.H. Salzman, T.S. Stappenbeck, R.J. Xavier, and C. Huttenhower), and Doris Duke Charitable Foundation grant 2014103 (to T.C. Liu).
Ta-Chiang Liu, Bhaskar Gurram, Megan T. Baldridge, Richard Head, Vy Lam, Chengwei Luo, Yumei Cao, Pippa Simpson, Michael Hayward, Mary L. Holtz, Pavlos Bousounis, Joshua Noe, Diana Lerner, Jose Cabrera, Vincent Biank, Michael Stephens, Curtis Huttenhower, Dermot P.B. McGovern, Ramnik J. Xavier, Thaddeus S. Stappenbeck, Nita H. Salzman
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