Ferroptosis is a death program executed via selective oxidation of arachidonic acid–phosphatidylethanolamines (AA-PE) by 15-lipoxygenases. In mammalian cells and tissues, ferroptosis has been pathogenically associated with brain, kidney, and liver injury/diseases. We discovered that a prokaryotic bacterium, Pseudomonas aeruginosa, that does not contain AA-PE can express lipoxygenase (pLoxA), oxidize host AA-PE to 15-hydroperoxy-AA-PE (15-HOO-AA-PE), and trigger ferroptosis in human bronchial epithelial cells. Induction of ferroptosis by clinical P. aeruginosa isolates from patients with persistent lower respiratory tract infections was dependent on the level and enzymatic activity of pLoxA. Redox phospholipidomics revealed elevated levels of oxidized AA-PE in airway tissues from patients with cystic fibrosis (CF) but not with emphysema or CF without P. aeruginosa. We believe that the evolutionarily conserved mechanism of pLoxA-driven ferroptosis may represent a potential therapeutic target against P. aeruginosa–associated diseases such as CF and persistent lower respiratory tract infections.
Haider H. Dar, Yulia Y. Tyurina, Karolina Mikulska-Ruminska, Indira Shrivastava, Hsiu-Chi Ting, Vladimir A. Tyurin, James Krieger, Claudette M. St. Croix, Simon Watkins, Erkan Bayir, Gaowei Mao, Catherine R. Armbruster, Alexandr Kapralov, Hong Wang, Matthew R. Parsek, Tamil S. Anthonymuthu, Abiola F. Ogunsola, Becca A. Flitter, Cody J. Freedman, Jordan R. Gaston, Theodore R. Holman, Joseph M. Pilewski, Joel S. Greenberger, Rama K. Mallampalli, Yohei Doi, Janet S. Lee, Ivet Bahar, Jennifer M. Bomberger, Hülya Bayır, Valerian E. Kagan
Enterovirus 71 (EV-A71) receptors that have been identified to date cannot fully explain the pathogenesis of EV-A71, which is an important global cause of hand-foot-and-mouth disease and life-threatening encephalitis. We identified an interferon-gamma (IFNγ)-inducible EV-A71 cellular entry factor, human tryptophanyl-tRNA synthetase (hWARS), using genome-wide RNAi library screening. The importance of hWARS in mediating virus entry and infectivity was confirmed by virus attachment, in vitro pull-down, antibody/antigen blocking, and CRISPR/Cas9. Upon IFNγ treatment, induced hyperexpression and plasma membrane translocation of hWARS were observed, which sensitized semi-permissive (human neuronal NT2)/non-permissive (mouse fibroblast L929) cells to EV-A71 infection. Our hWARS-transduced mouse infection model showed pathological changes similar to patients with severe EV-A71 infection. The expression of hWARS is also required for productive infection by other human enteroviruses, including the clinically important CV-A16 and EV-D68. This is the first report on the discovery of an entry factor, hWARS, which can be induced by IFNγ for EV-A71. Given that a high level of IFNγ was observed in patients with severe EV-A71 infection, our findings extend the knowledge of the pathogenicity of EV-A71 in relation to the expression of entry factor upon IFNγ stimulation and the therapeutic options for treating severe EV-A71-associated complications.
Man Lung Yeung, Lilong Jia, Cyril C.Y. Yip, Jasper F.W. Chan, Jade L.L. Teng, Kwok-Hung Chan, Jian-Piao Cai, Chaoyu Zhang, Anna J. Zhang, Wan-Man Wong, Kin-Hang Kok, Susanna K.P. Lau, Patrick C.Y. Woo, Janice Y.C. Lo, Dong-Yan Jin, Shin-Ru Shih, Kwok-Yung Yuen
B cells are increasingly recognised to play an important role in the ongoing control of hepatitis B virus (HBV). The development of antibodies against the viral surface antigen (HBsAg) constitutes the hallmark of resolution of acute infection and is a therapeutic goal for functional cure of chronic HBV (CHB). We characterised B cells directly ex vivo from the blood and liver of patients with CHB to investigate constraints on their antiviral potential. Unexpectedly, we found that HBsAg-specific B cells persisted in the blood and liver of many patients with CHB and were enriched for T-bet, a signature of antiviral potential in B cells. However purified, differentiated HBsAg-specific B cells from patients with CHB had defective antibody production, consistent with undetectable anti-HBs antibodies in vivo. HBsAg-specific and global B cells had an accumulation of CD21–CD27– atypical memory B cells (atMBC) with high expression of inhibitory receptors including PD-1. These atMBC demonstrated altered signalling, homing, differentiation into antibody-producing cells, survival and antiviral/pro-inflammatory cytokine production, that could be partially rescued by PD-1 blockade. Analysis of B cells within healthy and HBV-infected livers implicated the combination of this tolerogenic niche and HBV infection in driving PD-1hiatMBC and impairing B cell immunity.
Alice R. Burton, Laura J. Pallett, Laura E. McCoy, Kornelija Suveizdyte, Oliver E. Amin, Leo Swadling, Elena Alberts, Brian R. Davidson, Patrick T.F. Kennedy, Upkar S. Gill, Claudia Mauri, Paul A. Blair, Nadege Pelletier, Mala K. Maini
Chronic HBV (CHB) infection suppresses virus-specific T cells, but its impact on humoral immunity has been poorly analyzed. Here, we developed a dual staining method, which utilizes HBsAg labelled with fluorochromes as “baits”, for specific ex vivo detection of HBsAg-specific B cells and analysis of their quantity, function and phenotype. We studied healthy vaccinated subjects (n=18) and patients with resolved (n=21), acute (n=11) or chronic (n=96) HBV infection and observed that frequencies of circulating HBsAg-specific B cells are independent of the HBV infection status. In contrast, serum HBsAg presence affects function and phenotype of HBsAg-specific B cells that were unable to mature in vitro into antibody-secreting cells and displayed an increased expression of markers linked to hyperactivation (CD21low) and exhaustion (PD-1). Importantly, B cell alterations were not limited to HBsAg-specific B cells but affected the global B cell population. HBsAg-specific B cell maturation could be partially restored by a method involving the combination of IL-2, IL-21 and CD40L-expressing feeder cells, and further boosted by addition of anti-PD-1 antibodies.In conclusion, HBV infection has a marked impact on global and HBV-specific humoral immunity, yet HBsAg-specific B cells are amenable to a partial rescue by B cell maturing cytokines and PD-1 blockade.
Loghman Salimzadeh, Nina Le Bert, Charles-A. Dutertre, Upkar S. Gill, Evan W. Newell, Christian Frey, Magdeleine Hung, Nikolai Novikov, Simon Fletcher, Patrick T.F. Kennedy, Antonio Bertoletti
Autosomal dominant hyper IgE syndrome (AD-HIES), or Job’s syndrome, is a primary immune deficiency caused by dominant-negative mutations in STAT3. Recurrent Staphylococcus aureus skin abscesses are a defining feature of this syndrome. A widely held hypothesis that defects in peripheral Th17 differentiation confer this susceptibility has never been directly evaluated. To assess the cutaneous immune response in AD-HIES, we induced suction blisters in healthy volunteers (HVs) and patients with AD-HIES and then challenged the wound with lethally irradiated bacteria. We show that cutaneous production of IL-17A and IL-17F was normal in patients with AD-HIES. Overproduction of TNF-α differentiated the responses in AD-HIES from HVs. This was associated with reduced IL-10 family signaling in blister-infiltrating cells and defective epithelial cell function. Mouse models of AD-HIES recapitulated these aberrant epithelial responses to S. aureus and involved defective epithelial-to-mesenchymal transition (EMT) rather than a failure of bacterial killing. Defective responses in mouse models of AD-HIES and primary keratinocyte cultures from patients with AD-HIES could be reversed by TNF-α blockade and by drugs with reported modulatory effects on EMT. Our results identify these as potential therapeutic approaches in patients with AD-HIES suffering S. aureus infections.
Ian A. Myles, Erik D. Anderson, Noah J. Earland, Kol A. Zarember, Inka Sastalla, Kelli W. Williams, Portia Gough, Ian N. Moore, Sundar Ganesan, Cedar J. Fowler, Arian Laurence, Mary Garofalo, Douglas B. Kuhns, Mark D. Kieh, Arhum Saleem, Pamela A. Welch, Dirk A. Darnell, John I. Gallin, Alexandra F. Freeman, Steven M. Holland, Sandip K. Datta
The adjuvanted varicella-zoster virus glycoprotein E (VZV gE) subunit herpes zoster vaccine (HZ/su) confers higher protection against HZ than the live attenuated zoster vaccine (ZV). To understand the immunologic basis for the different efficacies of the vaccines, we compared immune responses to the vaccines in adults 50- to 85-year-old. gE-specific T cells were very low/undetectable before vaccination when analyzed by FluoroSpot and flow cytometry. Both ZV and HZ/su increased gE-specific responses, but at peak memory response (PMR) after vaccination (30 days after ZV or after the second dose of HZ/su) gE-specific CD4+ and CD8+ T-cell responses were ≥ 10-fold higher in HZ/su compared with ZV recipients. Comparing the vaccines, T cell memory responses, including gE- and VZV-IL2+ spot-forming cells (SFC), were higher in HZ/su recipients and cytotoxic and effector responses were lower. At 1 year after vaccination, all gE-Th1 and VZV-IL2+ SFC remained higher in HZ/su compared to ZV recipients. Mediation analyses showed that IL2+ PMR were necessary for the persistence of Th1 responses to either vaccine and VZV-IL2+ PMR explained 73% of the total effect of HZ/su on persistence. This emphasizes the biological importance of the memory responses, which were clearly superior in HZ/su compared with ZV participants.
Myron J. Levin, Miranda E. Kroehl, Michael J. Johnson, Andrew Hammes, Dominik Reinhold, Nancy Lang, Adriana Weinberg
HIV post-treatment controllers (PTCs) represent a natural model of sustained HIV remission, but they are rare and little is known about their viral reservoir. We obtained 1450 proviral sequences after near-full-length amplification for 10 PTCs and 16 post-treatment non-controllers (NCs). Before treatment interruption, the median intact and total reservoir size in PTCs was 7-fold lower than in NCs, but the proportion of intact, defective and total clonally-expanded viral genomes was not significantly different between the two groups. Quantification of total, but not intact, proviral genome copies predicted sustained HIV remission as 81% of NCs, but none of the PTCs, had a total proviral genome >4 copies per million PBMCs. The results highlight the restricted intact and defective HIV reservoir in PTCs and suggest that total proviral genome burden could act as the first biomarker for identifying PTCs. Defective, but not intact, proviral copy numbers correlated with levels of cell-associated HIV RNA, activated NK cell percentages and both HIV-specific CD4+ and CD8+ responses. These results support the concept that defective HIV genomes lead to viral antigen production and interact with both the innate and adaptive immune systems.
Radwa Sharaf, Guinevere Q. Lee, Xiaoming Sun, Behzad Etemad, Layla M. Aboukhater, Zixin Hu, Zabrina L. Brumme, Evgenia Aga, Ronald J. Bosch, Ying Wen, Golnaz Namazi, Ce Gao, Edward P. Acosta, Rajesh T. Gandhi, Jeffrey M. Jacobson, Daniel Skiest, David M. Margolis, Ronald Mitsuyasu, Paul Volberding, Elizabeth Connick, Daniel R. Kuritzkes, Michael M. Lederman, Xu G. Yu, Mathias Lichterfeld, Jonathan Z. Li
Lysine-63 (K63)–linked polyubiquitination of TRAF3 coordinates the engagement of pattern recognition receptors to recruited adaptor proteins and downstream activator TBK1 in pathways that induce type I interferon (IFN). Whether auto-ubiquitination or other E3 ligases mediate K63-linked TRAF3 polyubiquitination remains unclear. We demonstrated that mice deficient in E3 ligase gene Hectd3 remarkably increased host defense against infection by intracellular bacteria F. novicida, Mycobacterium, and Listeria by limiting bacterial dissemination. In the absence of HECTD3, type I IFN response was impaired during bacterial infection both in vivo and in vitro. HECTD3 regulated type I IFN production by mediating K63-linked polyubiquitination of TRAF3 at residue K138. The catalytic domain of HECTD3 regulated TRAF3 K63 polyubiquitination, which enabled TRAF3–TBK1 complex formation. Our study offers novel insights into mechanisms of TRAF3 modulation and provides potential therapeutic targets against infections by intracellular bacteria and inflammatory diseases.
Fubing Li, Yang Li, Huichun Liang, Tao Xu, Yanjie Kong, Maobo Huang, Ji Xiao, Xi Chen, Houjun Xia, Yingying Wu, Zhongmei Zhou, Xiaomin Guo, Chunmiao Hu, Chuanyu Yang, Xu Cheng, Ceshi Chen, Xiaopeng Qi
The human brain is an important site of HIV replication and persistence during antiretroviral therapy (ART). Direct evaluation of HIV infection in the brains of otherwise healthy individuals is not feasible; therefore, we performed a large-scale study of bone marrow/liver/thymus (BLT) humanized mice as an in vivo model to study HIV infection in the brain. Human immune cells, including CD4+ T cells and macrophages, were present throughout the BLT mouse brain. HIV DNA, HIV RNA, and/or p24+ cells were observed in the brains of HIV-infected animals, regardless of the HIV isolate used. HIV infection resulted in decreased numbers of CD4+ T cells, increased numbers of CD8+ T cells, and a decreased CD4+/CD8+ T cell ratio in the brain. Using humanized T cell–only mice (ToM), we demonstrated that T cells establish and maintain HIV infection of the brain in the complete absence of human myeloid cells. HIV infection of ToM resulted in CD4+ T cell depletion and a reduced CD4+/CD8+ T cell ratio. ART significantly reduced HIV levels in the BLT mouse brain, and the immune cell populations present were indistinguishable from those of uninfected controls, which demonstrated the effectiveness of ART in controlling HIV replication in the CNS and returning cellular homeostasis to a pre-HIV state.
Jenna B. Honeycutt, Baolin Liao, Christopher C. Nixon, Rachel A. Cleary, William O. Thayer, Shayla L. Birath, Michael D. Swanson, Patricia Sheridan, Oksana Zakharova, Francesca Prince, JoAnn Kuruc, Cynthia L. Gay, Chris Evans, Joseph J. Eron, Angela Wahl, J. Victor Garcia
Enterotoxigenic Escherichia coli (ETEC) infections are highly prevalent in developing countries where clinical presentations range from asymptomatic colonization to severe cholera-like illness. The molecular basis for these varied presentations, that may involve strain-specific virulence features as well as host factors, have not been elucidated. We demonstrate that when challenged with ETEC strain H10407, originally isolated from a case of cholera-like illness, blood group A human volunteers developed severe diarrhea more frequently than individuals from other blood groups. Interestingly, a diverse population of ETEC strains, including H10407, secrete a novel adhesin molecule, EtpA. As many bacterial adhesins also agglutinate red blood cells, we combined the use of glycan arrays, biolayer inferometry, and non-canonical amino acid labeling with hemagglutination studies to demonstrate that EtpA is a dominant ETEC blood group A specific lectin/hemagglutinin. Importantly, we also show that EtpA interacts specifically with glycans expressed on intestinal epithelial cells from blood group A individuals, and that EtpA-mediated bacterial-host interactions accelerate bacterial adhesion and the effective delivery both heat-labile and heat-stable toxins of ETEC. Collectively, these data provide additional insight into the complex molecular basis of severe ETEC diarrheal illness that may inform rational design of vaccines to protect those at highest risk.
Pardeep Kumar, F. Matthew Kuhlmann, Subhra Chakroborty, A. Louis Bourgeois, Jennifer Foulke-Abel, Brunda Tumala, Tim J. Vickers, David A. Sack, Barbara DeNearing, Clayton D. Harro, W. Shea Wright, Jeffrey C. Gildersleeve, Matthew A. Ciorba, Srikanth Santhanam, Chad K. Porter, Ramiro L. Gutierrez, Michael G. Prouty, Mark S. Riddle, Alexander Polino, Alaullah Sheikh, Mark Donowitz, James M. Fleckenstein
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