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Coya JM, Fraile-Ágreda V, de Tapia L, García-Fojeda B, Sáenz A, Bengoechea JA, Kronqvist N, Johansson J, Casals C. Cooperative action of SP-A and its trimeric recombinant fragment with polymyxins against Gram-negative respiratory bacteria. Front Immunol 2022; 13:927017. [PMID: 36159837 PMCID: PMC9493720 DOI: 10.3389/fimmu.2022.927017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 08/10/2022] [Indexed: 11/19/2022] Open
Abstract
The exploration of therapies combining antimicrobial lung proteins and conventional antibiotics is important due to the growing problem of multidrug-resistant bacteria. The aim of this study was to investigate whether human SP-A and a recombinant trimeric fragment (rfhSP-A) have cooperative antimicrobial activity with antibiotics against pathogenic Gram-negative bacteria. We found that SP-A bound the cationic peptide polymyxin B (PMB) with an apparent dissociation constant (K D) of 0.32 ± 0.04 µM. SP-A showed synergistic microbicidal activity with polymyxin B and E, but not with other antibiotics, against three SP-A-resistant pathogenic bacteria: Klebsiella pneumoniae, non-typable Haemophilus influenzae (NTHi), and Pseudomonas aeruginosa. SP-A was not able to bind to K. pneumoniae, NTHi, or to mutant strains thereof expressing long-chain lipopolysaccharides (or lipooligosaccharides) and/or polysaccharide capsules. In the presence of PMB, SP-A induced the formation of SP-A/PMB aggregates that enhance PMB-induced bacterial membrane permeabilization. Furthermore, SP-A bound to a molecular derivative of PMB lacking the acyl chain (PMBN) with a K D of 0.26 ± 0.02 μM, forming SP-A/PMBN aggregates. PMBN has no bactericidal activity but can bind to the outer membrane of Gram-negative bacteria. Surprisingly, SP-A and PMBN showed synergistic bactericidal activity against Gram-negative bacteria. Unlike native supratrimeric SP-A, the trimeric rfhSP-A fragment had small but significant direct bactericidal activity against K. pneumoniae, NTHi, and P. aeruginosa. rfhSP-A did not bind to PMB under physiological conditions but acted additively with PMB and other antibiotics against these pathogenic bacteria. In summary, our results significantly improve our understanding of the antimicrobial actions of SP-A and its synergistic action with PMB. A peptide based on SP-A may aid the therapeutic use of PMB, a relatively cytotoxic antibiotic that is currently being reintroduced into clinics due to the global problem of antibiotic resistance.
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Affiliation(s)
- Juan Manuel Coya
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - Víctor Fraile-Ágreda
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - Lidia de Tapia
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - Belén García-Fojeda
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - Alejandra Sáenz
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - José A. Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, United Kingdom
| | - Nina Kronqvist
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, Sweden
| | - Jan Johansson
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, Sweden
| | - Cristina Casals
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
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de Tapia L, García-Fojeda B, Kronqvist N, Johansson J, Casals C. The collectin SP-A and its trimeric recombinant fragment protect alveolar epithelial cells from the cytotoxic and proinflammatory effects of human cathelicidin in vitro. Front Immunol 2022; 13:994328. [PMID: 36105805 PMCID: PMC9464622 DOI: 10.3389/fimmu.2022.994328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 08/08/2022] [Indexed: 01/19/2023] Open
Abstract
Human cathelicidin (LL-37) is a defense peptide with antimicrobial activity against various pathogens. However, LL-37 can also trigger tissue injury by binding to host cell membranes. The cytotoxic effects of LL-37 may be especially relevant in chronic respiratory diseases characterized by increased LL-37. The aim of this study was to investigate whether the human collectin SP-A and a trimeric recombinant fragment thereof (rfhSP-A) can regulate the activities of LL-37. To this end, we studied the interaction of LL-37 with SP-A and rfhSP-A by intrinsic fluorescence, dynamic light scattering, and circular dichroism, as well as the effects of these proteins on the antimicrobial and cytotoxic activities of LL-37. Both SP-A and rfhSP-A bound LL-37 with high affinity at physiological ionic strength (KD = 0.45 ± 0.01 nM for SP-A and 1.22 ± 0.7 nM for rfhSP-A). Such interactions result in the reduction of LL-37-induced cell permeability and IL-8 release in human pneumocytes, mediated by P2X7 channels. Binding of LL-37 to SP-A did not modify the properties of SP-A or the antibacterial activity of LL-37 against respiratory pathogens (Klebsiella pneumoniae, Pseudomonas aeruginosa, and nontypeable Haemophilus influenzae). SP-A/LL-37 complexes showed a greater ability to aggregate LPS vesicles than LL-37, which reduces endotoxin bioactivity. These results reveal the protective role of native SP-A in controlling LL-37 activities and suggest a potential therapeutic effect of rfhSP-A in reducing the cytotoxic and inflammatory actions of LL-37, without affecting its microbicidal activity against Gram-negative pathogens.
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Affiliation(s)
- Lidia de Tapia
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - Belén García-Fojeda
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
| | - Nina Kronqvist
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, Sweden
| | - Jan Johansson
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, Sweden
| | - Cristina Casals
- Department of Biochemistry and Molecular Biology, Complutense University of Madrid, Madrid, Spain
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Šede M, Fridmanis J, Otikovs M, Johansson J, Rising A, Kronqvist N, Jaudzems K. Solution Structure of Tubuliform Spidroin N-Terminal Domain and Implications for pH Dependent Dimerization. Front Mol Biosci 2022; 9:936887. [PMID: 35775078 PMCID: PMC9237525 DOI: 10.3389/fmolb.2022.936887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 05/26/2022] [Indexed: 11/13/2022] Open
Abstract
The spidroin N-terminal domain (NT) is responsible for high solubility and pH-dependent assembly of spider silk proteins during storage and fiber formation, respectively. It forms a monomeric five-helix bundle at neutral pH and dimerizes at lowered pH, thereby firmly interconnecting the spidroins. Mechanistic studies with the NTs from major ampullate, minor ampullate, and flagelliform spidroins (MaSp, MiSp, and FlSp) have shown that the pH dependency is conserved between different silk types, although the residues that mediate this process can differ. Here we study the tubuliform spidroin (TuSp) NT from Argiope argentata, which lacks several well conserved residues involved in the dimerization of other NTs. We solve its structure at low pH revealing an antiparallel dimer of two five-α-helix bundles, which contrasts with a previously determined Nephila antipodiana TuSp NT monomer structure. Further, we study a set of mutants and find that the residues participating in the protonation events during dimerization are different from MaSp and MiSp NT. Charge reversal of one of these residues (R117 in TuSp) results in significantly altered electrostatic interactions between monomer subunits. Altogether, the structure and mutant studies suggest that TuSp NT monomers assemble by elimination of intramolecular repulsive charge interactions, which could lead to slight tilting of α-helices.
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Affiliation(s)
- Megija Šede
- Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, Latvia
| | - Jēkabs Fridmanis
- Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, Latvia
| | - Martins Otikovs
- Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, Latvia
| | - Jan Johansson
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, Sweden
| | - Anna Rising
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, Sweden
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Nina Kronqvist
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, Sweden
| | - Kristaps Jaudzems
- Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, Latvia
- Faculty of Chemistry, University of Latvia, Riga, Latvia
- *Correspondence: Kristaps Jaudzems,
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Sarr M, Kitoka K, Walsh-White KA, Kaldmäe M, Metlāns R, Tārs K, Mantese A, Shah D, Landreh M, Rising A, Johansson J, Jaudzems K, Kronqvist N. The dimerization mechanism of the N-terminal domain of spider silk proteins is conserved despite extensive sequence divergence. J Biol Chem 2022; 298:101913. [PMID: 35398358 PMCID: PMC9097459 DOI: 10.1016/j.jbc.2022.101913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 11/09/2022] Open
Abstract
The N-terminal (NT) domain of spider silk proteins (spidroins) is crucial for their storage at high concentrations and also regulates silk assembly. NTs from the major ampullate spidroin (MaSp) and the minor ampullate spidroin are monomeric at neutral pH and confer solubility to spidroins, whereas at lower pH, they dimerize to interconnect spidroins in a fiber. This dimerization is known to result from modulation of electrostatic interactions by protonation of well-conserved glutamates, although it is undetermined if this mechanism applies to other spidroin types as well. Here, we determine the solution and crystal structures of the flagelliform spidroin NT, which shares only 35% identity with MaSp NT, and investigate the mechanisms of its dimerization. We show that flagelliform spidroin NT is structurally similar to MaSp NT and that the electrostatic intermolecular interaction between Asp 40 and Lys 65 residues is conserved. However, the protonation events involve a different set of residues than in MaSp, indicating that an overall mechanism of pH-dependent dimerization is conserved but can be mediated by different pathways in different silk types.
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Affiliation(s)
- Médoune Sarr
- Department of Neurobiology, Care Sciences and Society, Division for Neurogeriatrics, Karolinska Institutet, 141 83 Huddinge, Sweden
| | - Kristine Kitoka
- Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, 1006, Latvia
| | - Kellie-Ann Walsh-White
- Department of Neurobiology, Care Sciences and Society, Division for Neurogeriatrics, Karolinska Institutet, 141 83 Huddinge, Sweden
| | - Margit Kaldmäe
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 65 Solna, Sweden
| | - Rimants Metlāns
- Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, 1006, Latvia
| | - Kaspar Tārs
- Latvian Biomedical Research and Study Centre, Riga, 1067, Latvia
| | | | - Dipen Shah
- ZoBio BV, J.H. Oortweg 19, 2333CH Leiden, the Netherlands
| | - Michael Landreh
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 65 Solna, Sweden
| | - Anna Rising
- Department of Neurobiology, Care Sciences and Society, Division for Neurogeriatrics, Karolinska Institutet, 141 83 Huddinge, Sweden; Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
| | - Jan Johansson
- Department of Neurobiology, Care Sciences and Society, Division for Neurogeriatrics, Karolinska Institutet, 141 83 Huddinge, Sweden; Department of Biosciences and Nutrition, Neo, Karolinska Institutet, 141 83 Huddinge, Sweden
| | - Kristaps Jaudzems
- Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, 1006, Latvia
| | - Nina Kronqvist
- Department of Neurobiology, Care Sciences and Society, Division for Neurogeriatrics, Karolinska Institutet, 141 83 Huddinge, Sweden; Department of Biosciences and Nutrition, Neo, Karolinska Institutet, 141 83 Huddinge, Sweden.
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