Peptidylarginine deiminases (PADs) are a family of calcium-dependent enzymes that are involved in a variety of human disorders, including cancer and autoimmune diseases. Although targeting PAD4 has shown no benefit in sepsis, the role of PAD2 remains unknown. Here, we report that PAD2 is engaged in sepsis and sepsis-induced acute lung injury in both human patients and mice. Pad2–/– or selective inhibition of PAD2 by a small molecule inhibitor increased survival and improved overall outcomes in mouse models of sepsis. Pad2 deficiency decreased neutrophil extracellular trap (NET) formation. Importantly, Pad2 deficiency inhibited Caspase-11–dependent pyroptosis in vivo and in vitro. Suppression of PAD2 expression reduced inflammation and increased macrophage bactericidal activity. In contrast to Pad2–/–, Pad4 deficiency enhanced activation of Caspase-11–dependent pyroptosis in BM-derived macrophages and displayed no survival improvement in a mouse sepsis model. Collectively, our findings highlight the potential of PAD2 as an indicative marker and therapeutic target for sepsis.
Yuzi Tian, Shibin Qu, Hasan B. Alam, Aaron M. Williams, Zhenyu Wu, Qiufang Deng, Baihong Pan, Jing Zhou, Baoling Liu, Xiuzhen Duan, Jianjie Ma, Santanu Mondal, Paul R. Thompson, Kathleen A. Stringer, Theodore J. Standiford, Yongqing Li
There is no cure for the more than 270 million people chronically infected with HBV. Nucleos(t)ide analogs (NUCs), the mainstay of anti-HBV treatment, block HBV reverse transcription. NUCs do not eliminate the intranuclear covalently closed circular DNA (cccDNA), from which viral RNAs, including pregenomic RNA (pgRNA), are transcribed. A key gap in designing a cure is understanding how NUCs affect HBV replication and transcription because serum markers yield an incomplete view of intrahepatic HBV. We applied single-cell laser capture microdissection and droplet digital PCR to paired liver biopsies collected from 5 HBV/HIV-coinfected persons who took NUCs over 2–4 years. From biopsy 1 to 2, proportions of HBV-infected hepatocytes declined with adherence to NUC treatment (P < 0.05); we extrapolated that eradication of HBV will take over 10 decades with NUCs in these participants. In individual hepatocytes, pgRNA levels diminished 28- to 73-fold during NUC treatment, corresponding with decreased tissue HBV core antigen staining (P < 0.01). In 4 out of 5 participants, hepatocytes with cccDNA but undetectable pgRNA (transcriptionally inactive) were present, and these were enriched in 3 participants during NUC treatment. Further work to unravel mechanisms of cccDNA transcriptional inactivation may lead to therapies that can achieve this in all hepatocytes, resulting in a functional cure.
Ashwin Balagopal, Tanner Grudda, Ruy M. Ribeiro, Yasmeen S. Saad, Hyon S. Hwang, Jeffrey Quinn, Michael Murphy, Kathleen Ward, Richard K. Sterling, Yang Zhang, Alan S. Perelson, Mark S. Sulkowski, William O. Osburn, Chloe L. Thio
Staphylococcus aureus is prevalent in surgical site infections (SSI) and leads to death in approximately 1% of patients. Phase IIB/III clinical trial results have demonstrated that vaccination against the iron-regulated surface determinant protein B (IsdB) is associated with an increased mortality rate in patients with SSI. Thus, we hypothesized that S. aureus induces nonneutralizing anti-IsdB antibodies, which facilitate bacterial entry into leukocytes to generate “Trojan horse” leukocytes that disseminate the pathogen. Since hemoglobin (Hb) is the primary target of IsdB, and abundant Hb-haptoglobin (Hb-Hp) complexes in bleeding surgical wounds are normally cleared via CD163-mediated endocytosis by macrophages, we investigated this mechanism in vitro and in vivo. Our results demonstrate that active and passive IsdB immunization of mice renders them susceptible to sepsis following SSI. We also found that a multimolecular complex containing S. aureus protein A–anti-IsdB–IsdB–Hb-Hp mediates CD163-dependent bacterial internalization of macrophages in vitro. Moreover, IsdB-immunized CD163–/– mice are resistant to sepsis following S. aureus SSI, as are normal healthy mice given anti-CD163–neutralizing antibodies. These genetic and biologic CD163 deficiencies did not exacerbate local infection. Thus, anti-IsdB antibodies are a risk factor for S. aureus sepsis following SSI, and disruption of the multimolecular complex and/or CD163 blockade may intervene.
Kohei Nishitani, Masahiro Ishikawa, Yugo Morita, Noriaki Yokogawa, Chao Xie, Karen L. de Mesy Bentley, Hiromu Ito, Stephen L. Kates, John L. Daiss, Edward M. Schwarz
Most of the patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mount a humoral immune response to the virus within a few weeks of infection, but the duration of this response and how it correlates with clinical outcomes has not been completely characterized. Of particular importance is the identification of immune correlates of infection that would support public health decision-making on treatment approaches, vaccination strategies, and convalescent plasma therapy. While ELISA-based assays to detect and quantitate antibodies to SARS-CoV-2 in patient samples have been developed, the detection of neutralizing antibodies typically requires more demanding cell-based viral assays. Here, we present a safe and efficient protein-based assay for the detection of serum and plasma antibodies that block the interaction of the SARS-CoV-2 spike protein receptor binding domain (RBD) with its receptor, angiotensin converting-enzyme 2 (ACE2). The assay serves as a surrogate neutralization assay and is performed on the same platform and in parallel with an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against the RBD, enabling a direct comparison. The results obtained with our assay correlate with those of two viral based assays, a plaque reduction neutralization test (PRNT) that uses live SARS-CoV-2 virus, and a spike pseudotyped viral-vector-based assay.
Kento T. Abe, Zhijie Li, Reuben Samson, Payman Samavarchi-Tehrani, Emelissa J. Valcourt, Heidi Wood, Patrick Budylowski, Alan P. Dupuis II, Roxie C. Girardin, Bhavisha Rathod, Jenny Wang, Miriam Barrios-Rodiles, Karen Colwill, Allison McGeer, Samira Mubareka, Jennifer L. Gommerman, Yves Durocher, Mario Ostrowski, Kathleen A. McDonough, Michael A. Drebot, Steven J. Drews, James M. Rini, Anne-Claude Gingras
The emergence of SARS-CoV-2 has created an international health crisis. Small animal models mirroring SARS-CoV-2 human disease are essential for medical countermeasure (MCM) development. Mice are refractory to SARS-CoV-2 infection due to low affinity binding to the murine angiotensin-converting enzyme 2 (ACE2) protein. Here we evaluated the pathogenesis of SARS-CoV-2 in male and female mice expressing the human ACE2 gene under the control of the keratin 18 promotor. In contrast to non-transgenic mice, intranasal exposure of K18-hACE2 animals to two different doses of SARS-CoV-2 resulted in acute disease including weight loss, lung injury, brain infection and lethality. Vasculitis was the most prominent finding in the lungs of infected mice. Transcriptomic analysis from lungs of infected animals revealed increases in transcripts involved in lung injury and inflammatory cytokines. In the lower dose challenge groups, there was a survival advantage in the female mice with 60% surviving infection whereas all male mice succumbed to disease. Male mice that succumbed to disease had higher levels of inflammatory transcripts compared to female mice. This is the first highly lethal murine infection model for SARS-CoV-2. The K18-hACE2 murine model will be valuable for the study of SARS-CoV-2 pathogenesis and the assessment of MCMs.
Joseph W. Golden, Curtis R. Cline, Xiankun Zeng, Aura R. Garrison, Brian D. Carey, Eric M. Mucker, Lauren E. White, Joshua D. Shamblin, Rebecca L. Brocato, Jun Liu, April M. Babka, Hypaitia B. Rauch, Jeffrey M. Smith, Bradley S. Hollidge, Collin Fitzpatrick, Catherine V. Badger, Jay W. Hooper
Background: Control of the tuberculosis (TB) pandemic remains hindered, in part, by a lack of simple and accurate measures of treatment efficacy. Current gold standard markers rely on sputum-based assays that are slow and challenging to implement. Previous work identified urinary N1, N12-diacetylspermine (DiAcSpm), neopterin, hydroxykynurenine, N-acetylhexosamine, ureidopropionic acid, sialic acid, and m/z 241.0903 as potential biomarkers of active pulmonary TB (ATB). Here, we evaluated their ability to serve as biomarkers of TB treatment response and mycobacterial load. Methods: We analyzed urine samples prospectively collected from two cohorts with ATB: 34 participants from African countries treated with first line TB therapy (HRZE) and followed for one year, and 35 participants from Haiti treated with either HRZE or an experimental drug followed for 14 days. Blinded samples were analyzed by untargeted high-performance liquid chromatography-coupled-time of flight-mass spectrometry. Results: Urinary levels of all seven molecules exhibited significant decreases by week 26 of successful treatment (p=0.01-p<0.0001), and positive correlations with sputum mycobacterial load (p<0.0001). Urinary levels of DiAcSpm exhibited significant decreases in participants treated with HRZE as early as 14 days (p<0.0001) but were unchanged in participants receiving ineffective therapy (p=0.14). Conclusion: Reductions in urinary DiAcSpm, neopterin, hydroxykynurenine, N-acetylhexosamine, ureidopropionic acid, sialic acid, and m/z 241.0903 correlated with successful anti-TB treatment and sputum mycobacterial load. Levels of DiAcSpm exhibited reductions capable of differentiating treatment success from failure as early as two weeks after the initiation of chemotherapy, commending its further development as a potentially simple, non-invasive biomarker of treatment response and bacterial load. Funding: This work was supported by the Clinical and Translational Science Center at Weill Cornell College of Medicine (NIH/NCATS 1 UL1 TR002384-02 and KL2TR000458), the Department of Defense (PR170782), the National Institute of Allergy and Infectious Disease grants (NIAID T32AI007613-16, K24 AI098627 and K23 AI131913), the NIH Fogarty International Center grants (R24 TW007988 and TW010062), the National Institute of Health grant (R01 GM135926 ), the Abby and Howard P. Milstein Program in Chemical Biology and Translational Medicine, and the Tuberculosis Research Units Networks (TBRU-N, AI111143).
Qianjing Xia, Myung Hee Lee, Kathleen F. Walsh, Kathrine McAulay, James M. Bean, Daniel W. Fitzgerald, Kathryn M. Dupnik, Warren D. Johnson, Jean W. Pape, Kyu Y. Rhee, Flonza Isa
Background Tuberculosis (TB) kills more people than any other infection and new diagnostic tests to identify active cases are urgently required. We aimed to discover and verify novel markers for TB in non-depleted plasma. Methods We applied an optimised quantitative proteomics discovery methodology based on multidimensional and orthogonal liquid chromatographic separation hyphenated with high-resolution mass spectrometry (q3D LC-MS) to study non-depleted plasma of 11 patients with active TB compared to 10 healthy control donors. Prioritised candidates were verified in an independent UK-based (n=118) and a South African cohorts (n=203). Results We generated the most comprehensive TB plasma proteome to date, profiling 5022 proteins spanning 11 orders-of-magnitude concentration range with diverse biochemical and molecular properties. We further analysed the predominantly low molecular weight sub-proteome; identifying 46 proteins with significantly increased and 90 with decreased abundance (peptide FDR ≤1%, q-value ≤0.05). Biological network analysis showed regulation of new pathways involving lipid and organophosphate ester transport. Verification was performed for novel candidate biomarkers (CFHR5, ILF2) in two independent cohorts. These proteins were elevated in both TB and other respiratory diseases (ORD). Receiver-operating-characteristics analyses using a 5-protein panel (CFHR5, LRG1, CRP, LBP and SAA1) exhibited discriminatory power in distinguishing between TB and ORD (AUC =0.81). Conclusions We report the most comprehensive TB plasma proteome to date, identifying numerous novel markers with verification in two independent cohorts, which led to a 5-protein biosignature with potential to improve TB diagnosis. With further development, these biomarkers have potential as a diagnostic triage test. Funding Colombia: Colciencias. UK: Medical Research Council, Innovate UK, National Institute for Health Research, Academy of Medical Sciences. Peru: Program for Advanced Research Capacities for AIDS. South Africa: Wellcome Centre for Infectious Diseases Research.
Diana J. Garay-Baquero, Cory H. White, Naomi F. Walker, Marc Tebruegge, Hannah F. Schiff, Cesar Ugarte-Gil, Stephen Morris-Jones, Ben G. Marshall, Antigoni Manousopoulou, John H. Adamson, Andres F. Vallejo, Magdalena K. Bielecka, Robert J. Wilkinson, Liku B. Tezera, Christopher H. Woelk, Spiros D. Garbis, Paul Elkington
Clostridioides difficile is a leading cause of nosocomial infection responsible for significant morbidity and mortality with limited options for therapy. Secreted C. difficile toxin B (TcdB) is a major contributor to disease pathology and select TcdB-specific Abs may protect against disease recurrence. However, the high frequency of recurrence suggests that the memory B cell response, essential for new Ab production following C. difficile re-exposure, is insufficient. We therefore isolated TcdB-specific memory B cells from individuals with a history of C. difficile infection and performed single-cell deep sequencing of their Ab genes. Herein, we report that TcdB-specific memory B cell-encoded antibodies showed somatic hypermutation but displayed limited isotype class switch. Memory B cell-encoded monoclonal antibodies generated from the gene sequences revealed low to moderate affinity for TcdB and a limited ability to neutralize TcdB. These findings indicate that memory B cells are an important factor in C. difficile disease recurrence.
Hemangi B. Shah, Kenneth Smith, Edgar J. Scott, II, Jason L. Larabee, Judith A. James, Jimmy D. Ballard, Mark L. Lang
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a novel tick-borne bunyavirus that recently emerged in East Asian countries. SFTS is characterized by high fever, thrombocytopenia, leukopenia, multiorgan failure, and hemorrhage with case fatality rates of 6.3% to 30%. Neither antivirals nor vaccines are available at present. We previously demonstrated that neutralizing antibodies specific for SFTSV glycoprotein (Gn) played a vital role in the survival of patients with SFTS. Nanobodies from camels present unique properties, such as thermostability, high affinity, and low immunogenicity. In the current study, mammalian expressed SFTSV Gn was used to immunize a camel, and functional nanobodies were isolated from the B cell nanobody library constructed from the immunized animal. Clone SNB02 was selected for in-depth analysis for its inhibition of SFTSV replication both in vitro and in vivo. We showed that SNB02 potently inhibited SFTSV infection and prevented thrombocytopenia in a humanized mouse model and is a potential candidate for therapeutics.
Xilin Wu, Yanlei Li, Bilian Huang, Xiaohua Ma, Linjing Zhu, Nan Zheng, Shijie Xu, Waqas Nawaz, Changping Xu, Zhiwei Wu
Critical illness is accompanied by the release of large amounts of the anaphylotoxin, C5a. C5a suppresses antimicrobial functions of neutrophils which is associated with adverse outcomes. The signalling pathways that mediate C5a-induced neutrophil dysfunction are incompletely understood. Healthy donor neutrophils exposed to purified C5a demonstrated a prolonged defect (7 hours) in phagocytosis of Staphylococcus aureus. Phosphoproteomic profiling of 2712 phosphoproteins identified persistent C5a signalling and selective impairment of phagosomal protein phosphorylation on exposure to S. aureus. Notable proteins included early endosomal marker ZFYVE16 and V-ATPase proton channel component ATPV1G1. A novel assay of phagosomal acidification demonstrated C5a-induced impairment of phagosomal acidification which was recapitulated in neutrophils from critically ill patients. Examination of the C5a-impaired protein phosphorylation indicated a role for the phosphatidylinositol 3-kinase VPS34 in phagosomal maturation. Inhibition of VPS34 impaired neutrophil phagosomal acidification and killing of S. aureus. This study provides a phosphoproteomic assessment of human neutrophil signalling in response to S. aureus and its disruption by C5a, identifying a defect in phagosomal maturation and new mechanisms of immune failure in critical illness.
Alexander J.T. Wood, Arlette M. Vassallo, Marie-Helene Ruchaud-Sparagano, Jonathan Scott, Carmelo Zinnato, Carmen Gonzalez-Tejedo, Kamal Kishore, Clive S. D’Santos, A. John Simpson, David K. Menon, Charlotte Summers, Edwin R. Chilvers, Klaus Okkenhaug, Andrew Conway Morris
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