Marie-Astrid Vernet, Stéphanie Reynard, Alexandra Fizet, Justine Schaeffer, Delphine Pannetier, Jeremie Guedj, Max Rives, Nadia Georges, Nathalie Garcia-Bonnet, Aboubacar I. Sylla, Péma Grovogui, Jean-Yves Kerherve, Christophe Savio, Sylvie Savio-Coste, Marie-Laure de Séverac, Philippe Zloczewski, Sandrine Linares, Souley Harouna, Bing M’Lebing Abdoul, Frederic Petitjean, Nenefing Samake, Susan Shepherd, Moumouni Kinda, Fara Roger Koundouno, Ludovic Joxe, Mathieu Mateo, Patrick Lecine, Audrey Page, Tang Maleki Tchamdja, Matthieu Schoenhals, Solenne Barbe, Bernard Simon, Tuan Tran-Minh, Christophe Longuet, François L’Hériteau, Sylvain Baize
Gram-negative pneumonia is a dangerous illness, and bacterial dissemination to the bloodstream during the infection is strongly associated with death. Antibiotic resistance among the causative pathogens has resulted in diminishing treatment options against this infection. Hepcidin is the master regulator of extracellular iron availability in vertebrates, but its role in the context of host defense is undefined. We hypothesized that hepcidin-mediated depletion of extracellular iron during Gram-negative pneumonia protects the host by limiting dissemination of bacteria to the bloodstream. During experimental pneumonia, hepcidin was induced in the liver in an IL-6–dependent manner and mediated a rapid decline in plasma iron. In contrast, hepcidin-deficient mice developed a paradoxical increase in plasma iron during infection associated with profound susceptibility to bacteremia. Incubation of bacteria with iron-supplemented plasma enhanced bacterial growth in vitro, and systemic administration of iron to WT mice similarly promoted increased susceptibility to bloodstream infection. Finally, treatment with a hepcidin analogue restored hypoferremia in hepcidin-deficient hosts, mediated bacterial control, and improved outcomes. These data show hepcidin induction during pneumonia to be essential to preventing bacterial dissemination by limiting extracellular iron availability. Hepcidin agonists may represent an effective therapy for Gram-negative infections in patients with impaired hepcidin production or signaling.
Kathryn R. Michels, Zhimin Zhang, Alexandra M. Bettina, R. Elaine Cagnina, Debora Stefanova, Marie D. Burdick, Sophie Vaulont, Elizabeta Nemeth, Tomas Ganz, Borna Mehrad
HIV-1 viremic controllers (VC) spontaneously control infection without antiretroviral treatment. Several studies indicate that IgG Abs from VCs induce enhanced responses from immune effector cells. Since signaling through Fc-γ receptors (FCGRs) modulate these Ab-driven responses, here we examine if enhanced FCGR activation is a common feature of IgG from VCs. Using an infected cell–based system, we observed that VC IgG stimulated greater FCGR2A and FCGR3A activation as compared with noncontrollers, independent of the magnitude of HIV-specific Ab binding or virus neutralization activities. Multivariate regression analysis showed that enhanced FCGR signaling was a significant predictor of VC status as compared with chronically infected patients (CIP) on highly active antiretroviral therapy (HAART). Unsupervised hierarchical clustering of patient IgG functions primarily grouped VC IgG profiles by enhanced FCGR2A, FCGR3A, or dual signaling activity. Our findings demonstrate that enhanced FCGR signaling is a common and significant predictive feature of VC IgG, with VCs displaying a distinct spectrum of FCGR activation profiles. Thus, profiling FCGR activation may provide a useful method for screening and distinguishing protective anti-HIV IgG responses in HIV-infected patients and in monitoring HIV vaccination regimens.
Raymond A. Alvarez, Ana M. Maestre, Kenneth Law, Natasha D. Durham, Maria Ines Barria, Akiko Ishii-Watabe, Minoru Tada, Manav Kapoor, Mathew T. Hotta, Gabriela Rodriguez-Caprio, Daniel S. Fierer, Ana Fernandez-Sesma, Viviana Simon, Benjamin K. Chen
Zika virus (ZIKV) is an important pathogen that causes not only neurologic, but also ocular, abnormalities. Thus, it is imperative that models to study ZIKV pathogenesis in the eye are developed to identify potential targets for interventions. Here, we studied ZIKV interactions with human retinal cells and evaluated ZIKV’s pathobiology in mouse eyes. We showed that cells lining the blood-retinal barrier (BRB), the retinal endothelium, and retinal pigment epithelium (RPE) were highly permissive and susceptible to ZIKV-induced cell death. Direct inoculation of ZIKV in eyes of adult C57BL/6 and IFN-stimulated gene 15 (ISG15) KO mice caused chorioretinal atrophy with RPE mottling, a common ocular manifestation of congenital ZIKV infection in humans. This response was associated with induced expression of multiple inflammatory and antiviral (IFNs) response genes in the infected mouse retina. Interestingly, ISG15 KO eyes exhibited severe chorioretinitis, which coincided with increased retinal cell death and higher ZIKV replication. Collectively, our study provides the first evidence to our knowledge that ZIKV causes retinal lesions and infects the cells lining the BRB and that ISG15 plays a role in retinal innate defense against ZIKV infection. Our mouse model can be used to study mechanisms underlying ZIKV-induced chorioretinitis and to gauge ocular antiviral therapies.
Pawan Kumar Singh, John-Michael Guest, Mamta Kanwar, Joseph Boss, Nan Gao, Mark S. Juzych, Gary W. Abrams, Fu-Shin Yu, Ashok Kumar
Adaptive changes in the genome of a locally predominant clinical isolate of the multidrug-resistant
Danielle Ahn, Hernán Peñaloza, Zheng Wang, Matthew Wickersham, Dane Parker, Purvi Patel, Antonius Koller, Emily I. Chen, Susan M. Bueno, Anne-Catrin Uhlemann, Alice Prince
Invasive pulmonary aspergillosis is a life-threatening mycosis that only affects patients with immunosuppression, chemotherapy-induced neutropenia, transplantation, or congenital immunodeficiency. We studied the clinical, genetic, histological, and immunological features of 2 unrelated patients without known immunodeficiency who developed extrapulmonary invasive aspergillosis at the ages of 8 and 18. One patient died at age 12 with progressive intra-abdominal aspergillosis. The other patient had presented with intra-abdominal candidiasis at age 9, and developed central nervous system aspergillosis at age 18 and intra-abdominal aspergillosis at age 25. Neither patient developed
Nikolaus Rieber, Roel P. Gazendam, Alexandra F. Freeman, Amy P. Hsu, Amanda L. Collar, Janyce A. Sugui, Rebecca A. Drummond, Chokechai Rongkavilit, Kevin Hoffman, Carolyn Henderson, Lily Clark, Markus Mezger, Muthulekha Swamydas, Maik Engeholm, Rebecca Schüle, Bettina Neumayer, Frank Ebel, Constantinos M. Mikelis, Stefania Pittaluga, Vinod K. Prasad, Anurag Singh, Joshua D. Milner, Kelli W. Williams, Jean K. Lim, Kyung J. Kwon-Chung, Steven M. Holland, Dominik Hartl, Taco W. Kuijpers, Michail S. Lionakis
Jennifer K Roe, Niclas Thomas, Eliza Gil, Katharine Best, Evdokia Tsaliki, Stephen Morris‑Jones, Sian Stafford, Nandi Simpson, Karolina D Witt, Benjamin Chain, Robert F Miller, Adrian Martineau, Mahdad Noursadeghi
Transcriptome profiles derived from the site of human disease have led to the identification of genes that contribute to pathogenesis, yet the complex mixture of cell types in these lesions has been an obstacle for defining specific mechanisms. Leprosy provides an outstanding model to study host defense and pathogenesis in a human infectious disease, given its clinical spectrum, which interrelates with the host immunologic and pathologic responses. Here, we investigated gene expression profiles derived from skin lesions for each clinical subtype of leprosy, analyzing gene coexpression modules by cell-type deconvolution. In lesions from tuberculoid leprosy patients, those with the self-limited form of the disease, dendritic cells were linked with
Megan S. Inkeles, Rosane M.B. Teles, Delila Pouldar, Priscila R. Andrade, Cressida A. Madigan, David Lopez, Mike Ambrose, Mahdad Noursadeghi, Euzenir N. Sarno, Thomas H. Rea, Maria T. Ochoa, M. Luisa Iruela-Arispe, William R. Swindell, Tom H.M. Ottenhoff, Annemieke Geluk, Barry R. Bloom, Matteo Pellegrini, Robert L. Modlin
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
Pirfenidone is a recently approved antifibrotic drug for the treatment of idiopathic pulmonary fibrosis (IPF). Because tuberculosis (TB) is characterized by granulomatous inflammation in conjunction with parenchymal destruction and replacement fibrosis, we sought to determine whether the addition of pirfenidone as an adjunctive, host-directed therapy provides a beneficial effect during antimicrobial treatment of TB. We hypothesized that pirfenidone’s antiinflammatory and antifibrotic properties would reduce inflammatory lung damage and increase antimicrobial drug penetration in granulomas to accelerate treatment response. The effectiveness of adjunctive pirfenidone during TB drug therapy was evaluated using a murine model of chronic TB. Mice treated with standard therapy 2HRZ/4HR (H, isoniazid; R, rifampin; and Z, pyrazinamide) were compared with 2 alternative regimens containing pirfenidone (Pf) (2HRZPf/4HRPf and 2HRZPf/4HR). Contrary to our hypothesis, adjunctive pirfenidone use leads to reduced bacterial clearance and increased relapse rates. This treatment failure is closely associated with the emergence of isoniazid monoresistant bacilli, increased cavitation, and significant lung pathology. While antifibrotic agents may eventually be used as part of adjunctive host-directed therapy of TB, this study clearly demonstrates that caution must be exercised. Moreover, as pirfenidone becomes more widely used in clinical practice, increased patient monitoring would be required in endemic TB settings.
Bintou A. Ahidjo, Mariama C. Maiga, Elizabeth A. Ihms, Mamoudou Maiga, Alvaro A. Ordonez, Laurene S. Cheung, Sarah Beck, Bruno B. Andrade, Sanjay Jain, William R. Bishai
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