Infectious disease
Abstract
Epoxyeicosatrienoic acids (EETs) have potent anti-inflammatory properties. Hydrolysis of EETs by soluble epoxide hydrolase (sEH/EPHX2) to less active diols attenuates their anti-inflammatory effects. Macrophage activation is critical to many inflammatory responses; however, the role of EETs and sEH in regulating macrophage function remains unknown. Lung bacterial clearance of S. pneumoniae was impaired in Ephx2-deficient (Ephx2-/-) mice and in mice treated with an sEH inhibitor. The EET receptor antagonist, EEZE, restored lung clearance of S. pneumoniae in Ephx2-/- mice. Ephx2-/- mice had normal lung Il-1β, Il-6 and Tnfα expression and macrophage recruitment to lungs during S. pneumoniae infection; however, Ephx2 disruption attenuated proinflammatory cytokine induction, Tlr2 and Pgylrp1 receptor upregulation and Rac1/2 and Cdc42 activation in PGN-stimulated macrophages. Consistent with these observations, Ephx2-/-macrophages displayed reduced phagocytosis of S. pneumoniae in vivo and in vitro. Heterologous overexpression of TLR2 and PGLYRP1 in Ephx2-/- macrophages restored macrophage activation and phagocytosis. Human macrophage function was similarly regulated by EETs. Together, these results demonstrate that EETs reduce macrophage activation and phagocytosis of S. pneumoniae through down-regulation of TLR2 and PGLYRP1 expression. Defining the role of EETs and sEH in macrophage function may lead to development of new therapeutic approaches for bacterial diseases.
Authors
Hong Li, J. Alyce Bradbury, Matthew L. Edin, Joan P. Graves, Artiom Gruzdev, Jennifer Cheng, Samantha L. Hoopes, Laura Miller-Degraff, Michael B. Fessler, Stavros Garantziotis, Shepherd H. Schurman, Darryl Craig Zeldin
Abstract
Authors
Manami Tsunoi, Sunao Iyoda, Tadayuki Iwase
Abstract
Authors
Inès Ambite, Ulrich Dobrindt, Catharina Svanborg
Abstract
Persons living with HIV (PLWH) are at increased risk of tuberculosis (TB). HIV-associated TB is often the result of recent infection with Mycobacterium tuberculosis (Mtb) followed by rapid progression to disease. Alveolar macrophages (AM) are the first cells of the innate immune system that engage Mtb, but how HIV and antiretroviral therapy (ART) impact on the anti-mycobacterial response of AM is not known. To investigate the impact of HIV and ART on the transcriptomic and epigenetic response of AM to Mtb, we obtained AM by bronchoalveolar lavage from 20 PLWH receiving ART, 16 control subjects who were HIV-free (HC), and 14 subjects who received ART as pre-exposure prophylaxis (PrEP) to prevent HIV infection. Following in-vitro challenge with Mtb, AM from each group displayed overlapping but distinct profiles of significantly up- and down-regulated genes in response to Mtb. Comparatively, AM isolated from both PLWH and PrEP subjects presented a substantially weaker transcriptional response. In addition, AM from HC subjects challenged with Mtb responded with pronounced chromatin accessibility changes while AM obtained from PLWH and PrEP subjects displayed no significant changes in their chromatin state. Collectively, these results revealed a stronger adverse effect of ART than HIV on the epigenetic landscape and transcriptional responsiveness of AM.
Authors
Wilian Correa-Macedo, Vinicius M. Fava, Marianna Orlova, Pauline Cassart, Ron Olivenstein, Joaquín Sanz, Yong Zhong Xu, Anne Dumaine, Renata H.M. Sindeaux, Vania Yotova, Alain Pacis, Josée Girouard, Barbara Kalsdorf, Christoph Lange, Jean-Pierre Routy, Luis B. Barreiro, Erwin Schurr
Abstract
BACKGROUND. Evidence supporting convalescent plasma (CP), one of the first investigational treatments for COVID-19, has been inconclusive, leading to conflicting recommendations. The primary objective was to perform a comparative effectiveness study of CP for all-cause, in-hospital mortality in patients with COVID-19. METHODS. The multicenter, electronic health records-based, retrospective study included 44,770 patients hospitalized with COVID-19 in one of 176 HCA Healthcare-affiliated community hospitals. Coarsened exact matching (1:k) was employed, resulting in a sample of 3,774 CP and 10,687 comparison patients. RESULTS. Examination of mortality using a shared frailty model, controlling for concomitant medications, date of admission, and days from admission to transfusion, demonstrated a significant association of CP with lower mortality risk relative to the comparison group (aHR=0.71, 95%CI 0.59-0.86, p<0.001). Examination of patient risk trajectories, represented by 400 clinico-demographic features from our Real-Time Risk Model (RTRM), indicated that patients who received CP recovered quicker. The stratification of days to transfusion revealed that CP within 3 days after admission, but not 4-7 days, was associated with a significantly lower mortality risk (aHR=0.53, 95%CI 0.47-0.60, p<0.001). CP serology level was inversely associated with mortality when controlling for its interaction with days to transfusion (HR=0.998, 95%CI 0.997-0.999, p=0.013) yet not reaching univariable significance. CONCLUSIONS. This large, diverse, multicenter cohort study demonstrated that CP, compared to matched controls, is significantly associated with reduced risk of in-hospital mortality. These observations highlight the utility of real-world evidence and suggest the need for further evaluation prior to abandoning CP as a viable therapy for COVID-19. FUNDING. This research was supported, in whole, by HCA Healthcare and/or an HCA Healthcare affiliated entity including Sarah Cannon and Genospace.
Authors
Shanna A. Arnold Egloff, Angela Junglen, Joseph S.A. Restivo, Marjorie Wongskhaluang, Casey Martin, Pratik Doshi, Daniel Schlauch, Gregg Fromell, Lindsay E. Sears, Mick Correll, Howard A. Burris, Charles F. LeMaistre
Abstract
Herein, we describe an extracellular function of the vertebrate high-mobility group box 1 protein (HMGB1) in the proliferation of bacterial biofilms. Within host cells, HMGB1 functions as a DNA architectural protein, similar to the ubiquitous DNABII family of bacterial proteins; despite that, these proteins share no amino acid sequence identity. Extracellularly, HMGB1 induces a proinflammatory immune response, whereas the DNABII proteins stabilize the extracellular DNA-dependent matrix that maintains bacterial biofilms. We showed that when both proteins converged on extracellular DNA within bacterial biofilms, HMGB1, unlike the DNABII proteins, disrupted biofilms both in vitro (including the high-priority ESKAPEE pathogens) and in vivo in 2 distinct animal models, albeit with induction of a strong inflammatory response that we attenuated by a single engineered amino acid change. We propose a model where extracellular HMGB1 balances the degree of induced inflammation and biofilm containment without excessive release of biofilm-resident bacteria.
Authors
Aishwarya Devaraj, Laura A. Novotny, Frank H. Robledo-Avila, John R. Buzzo, Lauren Mashburn-Warren, Joseph A. Jurcisek, Natalia O. Tjokro, Santiago Partida-Sanchez, Lauren O. Bakaletz, Steven D. Goodman
Abstract
BACKGROUND Necrotizing soft-tissue infections (NSTIs) are rapidly progressing infections frequently complicated by septic shock and associated with high mortality. Early diagnosis is critical for patient outcome, but challenging due to vague initial symptoms. Here, we identified predictive biomarkers for NSTI clinical phenotypes and outcomes using a prospective multicenter NSTI patient cohort.METHODS Luminex multiplex assays were used to assess 36 soluble factors in plasma from NSTI patients with positive microbiological cultures (n = 251 and n = 60 in the discovery and validation cohorts, respectively). Control groups for comparative analyses included surgical controls (n = 20), non-NSTI controls (i.e., suspected NSTI with no necrosis detected upon exploratory surgery, n = 20), and sepsis patients (n = 24).RESULTS Thrombomodulin was identified as a unique biomarker for detection of NSTI (AUC, 0.95). A distinct profile discriminating mono- (type II) versus polymicrobial (type I) NSTI types was identified based on differential expression of IL-2, IL-10, IL-22, CXCL10, Fas-ligand, and MMP9 (AUC >0.7). While each NSTI type displayed a distinct array of biomarkers predicting septic shock, granulocyte CSF (G-CSF), S100A8, and IL-6 were shared by both types (AUC >0.78). Finally, differential connectivity analysis revealed distinctive networks associated with specific clinical phenotypes.CONCLUSIONS This study identifies predictive biomarkers for NSTI clinical phenotypes of potential value for diagnostic, prognostic, and therapeutic approaches in NSTIs.TRIAL REGISTRATION ClinicalTrials.gov NCT01790698.FUNDING Center for Innovative Medicine (CIMED); Region Stockholm; Swedish Research Council; European Union; Vinnova; Innovation Fund Denmark; Research Council of Norway; Netherlands Organisation for Health Research and Development; DLR Federal Ministry of Education and Research; and Swedish Children’s Cancer Foundation.
Authors
Laura M. Palma Medina, Eivind Rath, Sanjeevan Jahagirdar, Trond Bruun, Martin B. Madsen, Kristoffer Strålin, Christian Unge, Marco Bo Hansen, Per Arnell, Michael Nekludov, Ole Hyldegaard, Magda Lourda, Vitor A.P. Martins dos Santos, Edoardo Saccenti, Steinar Skrede, Mattias Svensson, Anna Norrby-Teglund
Abstract
In view of emerging drug-resistant tuberculosis (TB), host directed adjunct therapies are urgently needed to improve treatment outcomes with currently available anti-TB therapies. One approach is to interfere with the formation of lipid-laden "foamy" macrophages in the host, as they provide a nutrient-rich host cell environment for Mycobacterium tuberculosis (Mtb). Here, we provide evidence that Wnt family member 6 (WNT6), a ligand of the evolutionarily conserved Wingless/Integrase 1 (WNT) signaling pathway, promotes foam cell formation by regulating key lipid metabolic genes including acetyl-CoA carboxylase-2 (ACC2) during pulmonary TB. Using genetic and pharmacological approaches, we demonstrated that lack of functional WNT6 or ACC2 significantly reduced intracellular triacylglycerol (TAG) levels and Mtb survival in macrophages. Moreover, treatment of Mtb-infected mice with a combination of a pharmacological ACC2 inhibitor and the anti-TB drug isoniazid (INH) reduced lung TAG and cytokine levels, as well as lung weights compared to treatment with INH alone. This combination also reduced Mtb bacterial numbers and the size of mononuclear cell infiltrates in livers of infected mice. In summary, our findings demonstrated that Mtb exploits WNT6/ACC2-induced storage of TAGs in macrophages to facilitate its intracellular survival, a finding opening new perspectives for host directed adjunctive treatment of pulmonary TB.
Authors
Julius Brandenburg, Sebastian Marwitz, Simone C. Tazoll, Franziska Waldow, Barbara Kalsdorf, Tim Vierbuchen, Thomas Scholzen, Annette Gross, Svenja Goldenbaum, Alexandra Hölscher, Martina Hein, Lara Linnemann, Maja Reimann, Andreas Kispert, Michael Leitges, Jan Rupp, Christoph Lange, Stefan Niemann, Jochen Behrends, Torsten Goldmann, Holger Heine, Ulrich E. Schaible, Christoph Hölscher, Dominik Schwudke, Norbert Reiling
Abstract
Macrophages deploy numerous strategies to combat invasion by microbes. One tactic is to restrict acquisition of diverse nutrients including trace metals, a process termed nutritional immunity. Intracellular pathogens adapt to a resource poor environment by marshalling mechanisms to harvest nutrients. Carbon acquisition is crucial for pathogen survival; compounds that reduce availability are a potential strategy to control intracellular replication. Treatment of macrophages with the glucose analog, 2-deoxy-D-glucose (2-DG), armed phagocytes to eliminate the intracellular fungal pathogen Histoplasma capsulatum in vitro and in vivo. Killing did not rely on altering access to carbon-containing molecules, or changes in ATP, ER stress, or autophagy. Unexpectedly, 2-DG undermined import of exogenous zinc into macrophages decreasing the quantity of cytosolic and phagosomal zinc. The fungus perished as a result of zinc starvation. This change in metal ingress was not ascribed to a defect in a single importer; rather, there was a collective impairment in transporter activity. This undescribed effect promotes the antifungal machinery of macrophages and expands the complexity of 2-DG activities far beyond manipulating glycolysis. Mechanistic metabolic studies employing 2-DG will have to consider its effect on zinc transport. Our preclinical data support consideration of this agent as a possible adjunctive therapy for histoplasmosis.
Authors
Diego C.P. Rossi, Julio A. Landero Figueroa, William R. Buesing, Kathleen Candor, Logan T. Blancett, Heather M. Evans, Rena Lenchitz, Bradford L. Crowther, Waleed Elsegeiny, Peter R. Williamson, Jan Rupp, George S. Deepe Jr.
Abstract
MHC-E, a non-classical MHC molecule, restricted CD8 T-cell responses have been associated with protection in an SIV/rhesus macaque model. The biological relevance of HLA-E restricted CD8 T-cell responses in HIV infection however remains unknown. In this study, CD8 T cells responding to HIV-1 Gag peptides presented by HLA-E were analyzed. Using in-vitro assays, we observed HLA-E restricted T-cell responses to what we believe to be a newly identified subdominant Gag-KL9 as well as a well-described immuno-dominant Gag-KF11 epitope in T-cell lines derived from chronically HIV-infected patients and also primed from healthy donors. Blocking of the HLA-E/KF11 binding by the B7 signal peptide resulted in decreased CD8 T-cell responses. KF11 presented via HLA-E in HIV infected cells was recognized by antigen specific CD8 T cells. Importantly, bulk CD8 T cells obtained from HIV infected individuals recognized infected cells via HLA-E presentation. Ex-vivo analyses at the epitope level showed a higher responder frequency of HLA-E restricted responses to KF11 compared to KL9. Taken together, our findings of HLA-E restricted HIV specific immune responses offer intriguing and possibly paradigm shifting insights into factors that contribute to the immuno-dominance of CD8 T-cell responses in HIV infection.
Authors
Anju Bansal, Mika N. Gehre, Kai Qin, Sarah Sterrett, Ayub Ali, Ying Dang, Sojan Abraham, Margaret C. Costanzo, Leon A. Venegas, Jianming Tang, N. Manjunath, Mark A. Brockman, Otto O. Yang, June Kan-Mitchell, Paul A. Goepfert
No posts were found with this tag.
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)