1
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Pontejo SM, Martinez S, Zhao A, Barnes K, de Anda J, Alimohamadi H, Lee EY, Dishman AF, Volkman BF, Wong GCL, Garboczi DN, Ballesteros A, Murphy PM. Chemokines Kill Bacteria by Binding Anionic Phospholipids without Triggering Antimicrobial Resistance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.25.604863. [PMID: 39091850 PMCID: PMC11291121 DOI: 10.1101/2024.07.25.604863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Classically, chemokines coordinate leukocyte trafficking during immune responses; however, many chemokines have also been reported to possess direct antibacterial activity in vitro. Yet, the bacterial killing mechanism of chemokines and the biochemical properties that define which members of the chemokine superfamily are antimicrobial remain poorly understood. Here we report that the antimicrobial activity of chemokines is defined by their ability to bind phosphatidylglycerol and cardiolipin, two anionic phospholipids commonly found in the bacterial plasma membrane. We show that only chemokines able to bind these two phospholipids kill Escherichia coli and Staphylococcus aureus and that they exert rapid bacteriostatic and bactericidal effects against E. coli with a higher potency than the antimicrobial peptide beta-defensin 3. Furthermore, our data support that bacterial membrane cardiolipin facilitates the antimicrobial action of chemokines. Both biochemical and genetic interference with the chemokine-cardiolipin interaction impaired microbial growth arrest, bacterial killing, and membrane disruption by chemokines. Moreover, unlike conventional antibiotics, E. coli failed to develop resistance when placed under increasing antimicrobial chemokine pressure in vitro. Thus, we have identified cardiolipin and phosphatidylglycerol as novel binding partners for chemokines responsible for chemokine antimicrobial action. Our results provide proof of principle for developing chemokines as novel antibiotics resistant to bacterial antimicrobial resistance mechanisms.
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2
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Weaver DF. Endogenous Antimicrobial-Immunomodulatory Molecules: Networking Biomolecules of Innate Immunity. Chembiochem 2024; 25:e202400089. [PMID: 38658319 DOI: 10.1002/cbic.202400089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/21/2024] [Accepted: 04/24/2024] [Indexed: 04/26/2024]
Abstract
Endogenous antimicrobial-immunomodulatory molecules (EAIMs) are essential to immune-mediated human health and evolution. Conventionally, antimicrobial peptides (AMPs) have been regarded as the dominant endogenous antimicrobial molecule; however, AMPs are not sufficient to account for the full spectrum of antimicrobial-immunomodulatory duality occurring within the human body. The threat posed by pathogenic microbes is pervasive with the capacity for widespread impact across many organ systems and multiple biochemical pathways; accordingly, the host needs the capacity to react with an equally diverse response. This can be attained by having EAIMs that traverse the full range of molecular size (small to large molecules) and structural diversity (including molecules other than peptides). This review identifies multiple molecules (peptide/protein, lipid, carbohydrate, nucleic acid, small organic molecule, and metallic cation) as EAIMs and discusses the possibility of cooperative, additive effects amongst the various EAIM classes during the host response to a microbial assault. This comprehensive consideration of the full molecular diversity of EAIMs enables the conclusion that EAIMs constitute a previously uncatalogued structurally diverse and collectively underappreciated immuno-active group of integrated molecular responders within the innate immune system's first line of defence.
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Affiliation(s)
- Donald F Weaver
- Departments of Chemistry and Medicine, University of Toronto, Krembil Research Institute, University Health Network, Toronto, ON, M5Y 0S8, Canada
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3
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Pampalone M, Cuscino N, Iannolo G, Amico G, Ricordi C, Vitale G, Carcione C, Castelbuono S, Scilabra SD, Coronnello C, Gruttadauria S, Pietrosi G. Human Amniotic MSC Response in LPS-Stimulated Ascites from Patients with Cirrhosis: FOXO1 Gene and Th17 Activation in Enhanced Antibacterial Activation. Int J Mol Sci 2024; 25:2801. [PMID: 38474048 DOI: 10.3390/ijms25052801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/14/2024] Open
Abstract
Spontaneous bacterial peritonitis (SBP) is a severe complication in patients with decompensated liver cirrhosis and is commonly treated with broad spectrum antibiotics. However, the rise of antibiotic resistance requires alternative therapeutic strategies. As recently shown, human amnion-derived mesenchymal stem cells (hA-MSCs) are able, in vitro, to promote bacterial clearance and modulate the immune and inflammatory response in SBP. Our results highlight the upregulation of FOXO1, CXCL5, CXCL6, CCL20, and MAPK13 in hA-MSCs as well as the promotion of bacterial clearance, prompting a shift in the immune response toward a Th17 lymphocyte phenotype after 72 h treatment. In this study, we used an in vitro SBP model and employed omics techniques (next-generation sequencing) to investigate the mechanisms by which hA-MSCs modify the crosstalk between immune cells in LPS-stimulated ascitic fluid. We also validated the data obtained via qRT-PCR, cytofluorimetric analysis, and Luminex assay. These findings provide further support to the hope of using hA-MSCs for the prevention and treatment of infective diseases, such as SBP, offering a viable alternative to antibiotic therapy.
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Affiliation(s)
- Mariangela Pampalone
- Ri.MED Foundation, 90127 Palermo, Italy
- Department of Laboratory Medicine and Advanced Biotechnologies, IRCCS ISMETT (Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione), 90127 Palermo, Italy
| | - Nicola Cuscino
- Department of Laboratory Medicine and Advanced Biotechnologies, IRCCS ISMETT (Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione), 90127 Palermo, Italy
| | - Gioacchin Iannolo
- Department of Laboratory Medicine and Advanced Biotechnologies, IRCCS ISMETT (Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione), 90127 Palermo, Italy
| | - Giandomenico Amico
- Ri.MED Foundation, 90127 Palermo, Italy
- Department of Laboratory Medicine and Advanced Biotechnologies, IRCCS ISMETT (Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione), 90127 Palermo, Italy
| | - Camillo Ricordi
- Cell Transplant Center, Diabetes Research Institute (DRI), University of Miami Miller School of Medicine, 1450 NW 10th Ave, Miami, FL 33136, USA
| | | | | | - Salvatore Castelbuono
- Department of Laboratory Medicine and Advanced Biotechnologies, IRCCS ISMETT (Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione), 90127 Palermo, Italy
| | - Simone Dario Scilabra
- Ri.MED Foundation, 90127 Palermo, Italy
- Department of Laboratory Medicine and Advanced Biotechnologies, IRCCS ISMETT (Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione), 90127 Palermo, Italy
| | | | - Salvatore Gruttadauria
- Department for the Treatment and Study of Abdominal Disease and Abdominal Transplantation, IRCCS ISMETT (Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione), UPMCI (University of Pittsburgh Medical Center Italy), 90127 Palermo, Italy
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, 95124 Catania, Italy
| | - Giada Pietrosi
- Department for the Treatment and Study of Abdominal Disease and Abdominal Transplantation, IRCCS ISMETT (Istituto Mediterraneo per i Trapianti e Terapie ad Alta Specializzazione), UPMCI (University of Pittsburgh Medical Center Italy), 90127 Palermo, Italy
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4
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Cui Z, Crawford MA, Rumble BA, Krogh MM, Hughes MA, Letteri RA. Antimicrobial Peptide-Poly(ethylene glycol) Conjugates: Connecting Molecular Architecture, Solution Properties, and Functional Performance. ACS POLYMERS AU 2024; 4:45-55. [PMID: 38371733 PMCID: PMC10870750 DOI: 10.1021/acspolymersau.3c00026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/20/2023] [Accepted: 11/27/2023] [Indexed: 02/20/2024]
Abstract
Antimicrobial peptides (AMPs) are promising alternatives to conventional antibiotics for treating infections caused by drug-resistant bacteria; yet, many peptides are limited by toxicity to eukaryotic cells and instability in biological environments. Conjugation to linear polymers that reduce cytotoxicity and improve stability, however, often decreases antimicrobial activity. In this work, we combine the biocompatibility advantages of poly(ethylene glycol) (PEG) with the efficacy merits of nonlinear polymer architectures that accommodate multiple AMPs per molecule. By conjugating a chemokine-derived AMP, stapled Ac-P9, to linear and star-shaped PEG with various arm numbers and lengths, we investigated the role of molecular architecture in solution properties (i.e., ζ-potential, size, and morphology) and performance (i.e., antimicrobial activity, hemolysis, and protease resistance). Linear, 4-arm, and 8-arm conjugates with 2-2.5 kDa PEG arms were found to form nanoscale structures in solution with lower ζ-potentials relative to the unconjugated AMP, suggesting that the polymer partially shields the cationic AMP. Reducing the length of the PEG arms of the 8-arm conjugate to 1.25 kDa appeared to better reveal the peptide, seen by the increased ζ-potential, and promote assembly into particles with a larger size and defined spherical morphology. The antimicrobial effects exerted by the short 8-arm conjugate rivaled that of the unconjugated peptide, and the AMP constituents of the short 8-arm conjugate were protected from proteolytic degradation. All other conjugates examined also imparted a degree of protease resistance, but exhibited some reduced level of antimicrobial activity as compared to the AMP alone. None of the conjugates caused significant cytotoxic effects, which bodes well for their future potential to treat infections. While enhancing proteolytic stability often comes with the cost of lower antimicrobial activity, we have found that presenting AMPs at high density on a neutral nonlinear polymer strikes a favorable balance, exhibiting both enhanced stability and high antimicrobial activity.
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Affiliation(s)
- Zixian Cui
- Department
of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22903, United States
| | - Matthew A. Crawford
- Division
of Infectious Diseases & International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia 22908, United States
| | - Blake A. Rumble
- Division
of Infectious Diseases & International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia 22908, United States
| | - Megan M. Krogh
- Division
of Infectious Diseases & International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia 22908, United States
| | - Molly A. Hughes
- Division
of Infectious Diseases & International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia 22908, United States
| | - Rachel A. Letteri
- Department
of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22903, United States
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5
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Disparate Regions of the Human Chemokine CXCL10 Exhibit Broad-Spectrum Antimicrobial Activity against Biodefense and Antibiotic-Resistant Bacterial Pathogens. ACS Infect Dis 2022; 9:122-139. [PMID: 36475632 PMCID: PMC9841529 DOI: 10.1021/acsinfecdis.2c00456] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
CXCL10 is a pro-inflammatory chemokine produced by the host in response to microbial infection. In addition to canonical, receptor-dependent actions affecting immune-cell migration and activation, CXCL10 has also been found to directly kill a broad range of pathogenic bacteria. Prior investigations suggest that the bactericidal effects of CXCL10 occur through two distinct pathways that compromise the cell envelope. These observations raise the intriguing notion that CXCL10 features a separable pair of antimicrobial domains. Herein, we affirm this possibility through peptide-based mapping and structure/function analyses, which demonstrate that discrete peptides derived from the N- and C-terminal regions of CXCL10 mediate bacterial killing. The N-terminal derivative, peptide P1, exhibited marked antimicrobial activity against Bacillus anthracis vegetative bacilli and spores, as well as antibiotic-resistant clinical isolates of Klebsiella pneumoniae, Acinetobacter baumannii, Enterococcus faecium, and Staphylococcus aureus, among others. At bactericidal concentrations, peptide P1 had a minimal degree of chemotactic activity, but did not cause red blood cell hemolysis or cytotoxic effects against primary human cells. The C-terminal derivative, peptide P9, exhibited antimicrobial effects, but only against Gram-negative bacteria in low-salt medium─conditions under which the peptide can adopt an α-helical conformation. The introduction of a hydrocarbon staple induced and stabilized α-helicity; accordingly, stapled peptide P9 displayed significantly improved bactericidal effects against both Gram-positive and Gram-negative bacteria in media containing physiologic levels of salt. Together, our findings identify and characterize the antimicrobial regions of CXCL10 and functionalize these novel determinants as discrete peptides with potential therapeutic utility against difficult-to-treat pathogens.
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Zhang Y, Li X, Li J, Liu D, Zhai L, Wang X, Abdurahman A, Yokota H, Zhang P. Knee Loading Enhances the Migration of Adipose-Derived Stem Cells to the Osteoarthritic Sites Through the SDF-1/CXCR4 Regulatory Axis. Calcif Tissue Int 2022; 111:171-184. [PMID: 35429248 DOI: 10.1007/s00223-022-00976-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/30/2022] [Indexed: 11/02/2022]
Abstract
Osteoarthritis (OA) is a whole joint disorder that is characterized by cartilage damage and abnormal remodeling of subchondral bone. Injecting adipose-derived stem cells (ASCs) into the knee joint cavity can assist in repairing osteoarthritic joints, but their ability to migrate to the damaged site is limited. Our previous studies have shown that knee loading can improve the symptoms of OA, but the effect and mechanism of knee loading on the migration of ASCs in OA remain unclear. We employed a mouse model of OA in the knee and applied knee loading (1 N at 5 Hz for 6 min/day for 2 weeks) after the intra-articular injection of ASCs. The cartilage and subchondral bone repair were assessed by histopathological analysis. Immunofluorescence assays were also used to analyze the migration of ASCs. Using cell cultures, we evaluated the migration of ASCs using the transwell migration and wound healing assays. In vivo experiments showed that knee loading promoted the migration of ASCs, increased the local SDF-1 level, and accelerated the repair of the OA-damaged sites. Mechanistically, the observed effects were blocked by the SDF-1/CXCR4 inhibitor. The in vitro results further revealed that knee loading promoted the migration of ASCs and the inhibition of SDF-1/CXCR4 significantly suppressed the beneficial loading effect. The results herein suggested that the migration of ASCs was enhanced by knee loading through the SDF-1/CXCR4 regulatory axis, and mechanical loading promoted the joint-protective effect of ASCs.
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Affiliation(s)
- Yifan Zhang
- Department of Anatomy and Histology, School of Basic Medical Sciences, Tianjin Medical University, 22 Qixiangtai Road, Tianjin, 300070, China
| | - Xinle Li
- Department of Anatomy and Histology, School of Basic Medical Sciences, Tianjin Medical University, 22 Qixiangtai Road, Tianjin, 300070, China
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Medical University, Tianjin, 300070, China
| | - Jie Li
- Department of Anatomy and Histology, School of Basic Medical Sciences, Tianjin Medical University, 22 Qixiangtai Road, Tianjin, 300070, China
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Medical University, Tianjin, 300070, China
| | - Daquan Liu
- Department of Anatomy and Histology, School of Basic Medical Sciences, Tianjin Medical University, 22 Qixiangtai Road, Tianjin, 300070, China
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Medical University, Tianjin, 300070, China
| | - Lidong Zhai
- Department of Anatomy and Histology, School of Basic Medical Sciences, Tianjin Medical University, 22 Qixiangtai Road, Tianjin, 300070, China
| | - Xuetong Wang
- Department of Anatomy and Histology, School of Basic Medical Sciences, Tianjin Medical University, 22 Qixiangtai Road, Tianjin, 300070, China
| | - Abdusami Abdurahman
- Department of Anatomy and Histology, School of Basic Medical Sciences, Tianjin Medical University, 22 Qixiangtai Road, Tianjin, 300070, China
| | - Hiroki Yokota
- Department of Biomedical Engineering, Indiana University-Purdue University, Indianapolis, IN, 46202, USA
| | - Ping Zhang
- Department of Anatomy and Histology, School of Basic Medical Sciences, Tianjin Medical University, 22 Qixiangtai Road, Tianjin, 300070, China.
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Medical University, Tianjin, 300070, China.
- Tianjin Key Laboratory of Spine and Spinal Cord, Tianjin Medical University, Tianjin, 300052, China.
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7
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Aldous AM, Joy C, Daniels J, Jais M, Simmens SJ, Magnus M, Roberts A, Connors K, Capozzi B, Mohamed H, Juzumaite M, Devore H, Moriarty T, Hatch Schultz C, Zumer M, Simon G, Ghosh M. Recent sexual violence exposure is associated with immune biomarkers of HIV susceptibility in women. Am J Reprod Immunol 2021; 86:e13432. [PMID: 33894020 DOI: 10.1111/aji.13432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/13/2021] [Accepted: 04/16/2021] [Indexed: 11/28/2022] Open
Abstract
PROBLEM HIV/AIDS and sexual violence act synergistically and compromise women's health. Yet, immuno-biological mechanisms linking sexual violence and increased HIV susceptibility are poorly understood. METHODS We conducted a cross-sectional pilot study of HIV-uninfected women, comparing 13 women exposed to forced vaginal penetration within the past 12 weeks (Exposed) with 25 Non-Exposed women. ELISA assays were conducted for 49 biomarkers associated with HIV pathogenesis in plasma and cervicovaginal lavage (CVL). Differences between Exposed and Non-Exposed were analyzed by linear and logistic regression, using propensity score weighting to control for age, race, socioeconomic status, menstrual cycle, and contraceptive use. RESULTS In CVL, Exposed women had significantly reduced chemokines MIP-3α (p < .01), MCP-1 (p < .01), and anti-HIV/wound-healing thrombospondin-1 (p = .03). They also had significantly increased inflammatory cytokine IL-1α (p < 0.01) and were more likely to have detectable wound-healing PDGF (p = .02). In plasma, Exposed women had reduced chemokines MIP-3α (p < .01) and IL-8 (p < .01), anti-inflammatory cytokine TGF-β (p = .02), anti-HIV/antimicrobial HBD-2 (p = .02), and wound-healing MMP-1 (p = 0.02). They also had increased thrombospondin-1 (p < .01) and Cathepsin B (p = .01). After applying the stringent method of false discovery rate adjustment, differences for IL-1α (p = .05) and MCP-1 (p = .03) in CVL and MIP-3α (p = .03) in plasma remained significant. CONCLUSIONS We report systemic and mucosal immune dysregulation in women exposed to sexual violence. As these biomarkers have been associated with HIV pathogenesis, dysregulation may increase HIV susceptibility.
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Affiliation(s)
- Annette M Aldous
- Department of Epidemiology, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - Christopher Joy
- Department of Epidemiology, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - Jason Daniels
- Department of Epidemiology, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - Mariel Jais
- Department of Epidemiology, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - Samuel J Simmens
- Department of Biostatistics and Bioinformatics, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - Manya Magnus
- Department of Epidemiology, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - Afsoon Roberts
- Division of Infectious Diseases, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Kaleigh Connors
- Department of Epidemiology, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - Brendan Capozzi
- Department of Epidemiology, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - Hani Mohamed
- Department of Epidemiology, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - Monika Juzumaite
- Department of Epidemiology, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - Heather Devore
- District of Columbia Forensic Nurse Examiners, Washington, DC, USA
| | | | | | - Maria Zumer
- Medical Faculty Associates, Inc., The George Washington University, Washington, DC, USA
| | - Gary Simon
- Division of Infectious Diseases, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Mimi Ghosh
- Department of Epidemiology, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
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8
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Inhibition of Human Neutrophil Functions In Vitro by Multiple Sclerosis Disease-Modifying Therapies. J Clin Med 2020; 9:jcm9113542. [PMID: 33147889 PMCID: PMC7692529 DOI: 10.3390/jcm9113542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/21/2020] [Accepted: 10/30/2020] [Indexed: 02/06/2023] Open
Abstract
There is a growing optimism about the potential of new disease-modifying therapies (DMTs) in the management of relapsing-remitting multiple sclerosis (RRMS) patients. However, this initial enthusiasm has been tempered by evidence indicating that multiple sclerosis (MS) patients undergoing DMT may be at higher risk of developing infections through incompletely understood mechanisms. As neutrophils provide the first line of defense against pathogens, here we have compared the effects of some of the commonly used MS DMTs (i.e., moderate-efficacy injective, first-line: interferonβ-1b (IFNβ-1b), glatiramer acetate (GA); and high-efficacy, second-line: fingolimod (FTY) and natalizumab (NAT)) on the in vitro viability and functions of neutrophils isolated from healthy subjects. All the DMTs tested impaired the ability of neutrophils to kill Klebsiella pneumoniae, whereas none of them affected the rate of neutrophil apoptosis or CD11b and CD62L cell surface expression. Intriguingly, only FTY exposure negatively affected K. pneumoniae-induced production of reactive oxygen species (ROS) in polymorphonuclear leukocytes (PMNs). Furthermore, neutrophils exposed to K. pneumoniae secreted enhanced amounts of CXCL8, IL-1β and TNF-α, which were differentially regulated following DMT pretreatment. Altogether, these findings suggest that DMTs may increase the susceptibility of MS patients to microbial infections, in part, through inhibition of neutrophil functions. In light of these data, we recommend that the design of personalized therapies for RRMS patients should take into account not just the mechanism of action of the chosen DMT but also the potential risk of infection associated with the administration of such therapeutic compounds to this highly vulnerable population.
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9
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Dishman AF, Lee MW, de Anda J, Lee EY, He J, Huppler AR, Wong GCL, Volkman BF. Switchable Membrane Remodeling and Antifungal Defense by Metamorphic Chemokine XCL1. ACS Infect Dis 2020; 6:1204-1213. [PMID: 32243126 PMCID: PMC7258946 DOI: 10.1021/acsinfecdis.0c00011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
![]()
Antimicrobial peptides (AMPs) are
a class of molecules which generally
kill pathogens via preferential cell membrane disruption. Chemokines
are a family of signaling proteins that direct immune cell migration
and share a conserved α–β tertiary structure. Recently,
it was found that a subset of chemokines can also function as AMPs,
including CCL20, CXCL4, and XCL1. It is therefore surprising that
machine learning based analysis predicts that CCL20 and CXCL4’s
α-helices are membrane disruptive, while XCL1’s helix
is not. XCL1, however, is the only chemokine known to be a metamorphic
protein which can interconvert reversibly between two distinct native
structures (a β-sheet dimer and the α–β chemokine
structure). Here, we investigate XCL1’s antimicrobial mechanism
of action with a focus on the role of metamorphic folding. We demonstrate
that XCL1 is a molecular “Swiss army knife” that can
refold into different structures for distinct context-dependent functions:
whereas the α–β chemokine structure controls cell
migration by binding to G-Protein Coupled Receptors (GPCRs), we find
using small angle X-ray scattering (SAXS) that only the β-sheet
and unfolded XCL1 structures can induce negative Gaussian curvature
(NGC) in membranes, the type of curvature topologically required for
membrane permeation. Moreover, the membrane remodeling activity of
XCL1’s β-sheet structure is strongly dependent on membrane
composition: XCL1 selectively remodels bacterial model membranes but
not mammalian model membranes. Interestingly, XCL1 also permeates
fungal model membranes and exhibits anti-Candida activity in vitro, in contrast to the usual mode of antifungal defense
which requires Th17 mediated cell-based responses. These observations
suggest that metamorphic XCL1 is capable of a versatile multimodal
form of antimicrobial defense.
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Affiliation(s)
- Acacia F. Dishman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 United States
| | - Michelle W. Lee
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Jaime de Anda
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Ernest Y. Lee
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California 90095, United States
- UCLA-Caltech Medical Scientist Training Program, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Jie He
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 United States
| | - Anna R. Huppler
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 United States
| | - Gerard C. L. Wong
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Brian F. Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 United States
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10
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Thomas MA, He J, Peterson FC, Huppler AR, Volkman BF. The Solution Structure of CCL28 Reveals Structural Lability that Does Not Constrain Antifungal Activity. J Mol Biol 2018; 430:3266-3282. [PMID: 29913161 DOI: 10.1016/j.jmb.2018.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/18/2018] [Accepted: 06/04/2018] [Indexed: 11/16/2022]
Abstract
The chemokine CCL28 is constitutively expressed in mucosal tissues and is abundant in low-salt mucosal secretions. Beyond its traditional role as a chemoattractant, CCL28 has been shown to act as a potent and broad-spectrum antimicrobial agent with particular efficacy against the commensal fungus and opportunistic pathogen Candida albicans. However, the structural features that allow CCL28 to perform its chemotactic and antimicrobial functions remain unknown. Here, we report the structure of CCL28, solved using nuclear magnetic resonance spectroscopy. CCL28 adopts the canonical chemokine tertiary fold, but also has a disordered C-terminal domain that is partially tethered to the core by a non-conserved disulfide bond. Structure-function analysis reveals that removal of the C-terminal tail reduces the antifungal activity of CCL28 without disrupting its structural integrity. Conversely, removal of the non-conserved disulfide bond destabilizes the tertiary fold of CCL28 without altering its antifungal effects. Moreover, we report that CCL28 unfolds in response to low pH but is stabilized by the presence of salt. To explore the physiologic relevance of the observed structural lability of CCL28, we investigated the effects of pH and salt on the antifungal activity of CCL28 in vitro. We found that low pH enhances the antifungal potency of CCL28, but also that this pH effect is independent of CCL28's tertiary fold. Given its dual role as a chemoattractant and antimicrobial agent, our results suggest that changes in the salt concentration or pH at mucosal sites may fine-tune CCL28's functional repertoire by adjusting the thermostability of its structure.
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Affiliation(s)
- Monica A Thomas
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jie He
- Department of Pediatrics, Division of Infectious Disease, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Francis C Peterson
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Anna R Huppler
- Department of Pediatrics, Division of Infectious Disease, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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