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Shandilya UK, Sharma A, Mallikarjunappa S, Guo J, Mao Y, Meade KG, Karrow NA. CRISPR-Cas9-mediated knockout of TLR4 modulates Mycobacterium avium ssp. paratuberculosis cell lysate-induced inflammation in bovine mammary epithelial cells. J Dairy Sci 2021; 104:11135-11146. [PMID: 34253365 DOI: 10.3168/jds.2021-20305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/25/2021] [Indexed: 11/19/2022]
Abstract
Toll-like receptor 4 (TLR4) is a pattern-recognition receptor involved in the recognition of microbial pathogens and host alarmins. Ligation to TLR4 initiates a signaling cascade that leads to inflammation. Polymorphisms in bovine TLR4 have been associated with Mycobacterium avium ssp. paratuberculosis (MAP) susceptibility and resistance, the cause of Johne's disease, and milk somatic cell score, a biomarker of mastitis. Although the contribution of TLR4 to recognition of bacterial lipopolysaccharide (LPS) has been well characterized, its role in MAP recognition is less certain. Clustered regularly interspaced short palindromic repeats-Cas9 mediated gene editing was performed to generate TLR4 knockout (KO) mammary epithelial cells to determine if TLR4 expression is involved in the initiation of the host inflammatory response to MAP cell lysate (5 and 10 µg/mL) and Escherichia coli LPS (5 µg/mL). The absence of TLR4 in KO cells resulted in enhanced expression of key inflammatory genes (TNFA and IL6), anti-inflammatory genes (IL10 and SOCS3), and supernatant cytokine and chemokine levels (TNF-α, IL-6, IL-10, CCL3) in response to the MAP cell lysate (10 µg/mL). However, in response to LPS, the KO cells showed reduced expression of key inflammatory genes (TNFA, IL1A, IL1B, and IL6) and supernatant cytokine levels (TNF-α, IL-6, CCL2, IL-8) as compared with unedited cells. Overall, these results confirm that TLR4 is essential for eliciting inflammation in response to LPS; however, exacerbated gene and protein expression in TLR4 KO cells in response to MAP cell lysate suggests a different mechanism of infection and host response for MAP, at least in terms of how it interacts with TLR4. These novel findings show potential divergent roles for TLR4 in mycobacterial infections, and this may have important consequences for the therapeutic control of inflammation in cattle.
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Affiliation(s)
- Umesh K Shandilya
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, N1G 2W1, Ontario, Canada
| | - A Sharma
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, N1G 2W1, Ontario, Canada
| | - S Mallikarjunappa
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, N1G 2W1, Ontario, Canada
| | - J Guo
- Key Laboratory for Animal Genetics, Breeding, Reproduction and Molecular Design of Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, P R China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Y Mao
- Key Laboratory for Animal Genetics, Breeding, Reproduction and Molecular Design of Jiangsu Province, College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, P R China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - K G Meade
- Animal and Bioscience Research Department, Teagasc, Grange, Co. Meath, Ireland, C15 PW93; School of Agriculture and Food Science, University College Dublin, Ireland, D04 V1W8
| | - N A Karrow
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, N1G 2W1, Ontario, Canada.
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Mikkelsen H, Aagaard C, Nielsen SS, Jungersen G. Review of Mycobacterium avium subsp. paratuberculosis antigen candidates with diagnostic potential. Vet Microbiol 2011; 152:1-20. [DOI: 10.1016/j.vetmic.2011.03.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 03/02/2011] [Accepted: 03/10/2011] [Indexed: 11/25/2022]
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Ferwerda G, Kullberg BJ, de Jong DJ, Girardin SE, Langenberg DML, van Crevel R, Ottenhoff THM, Van der Meer JWM, Netea MG. Mycobacterium paratuberculosis is recognized by Toll-like receptors and NOD2. J Leukoc Biol 2007; 82:1011-8. [PMID: 17652449 DOI: 10.1189/jlb.0307147] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mycobacterium paratuberculosis has been suggested to be involved in the pathogenesis of Crohn's disease (CD). The importance of microorganisms in CD is supported by the association of CD with mutations in the intracellular pathogen recognition receptor (PRR) nucleotide-binding oligomerization domain 2 (NOD2). The aim of this study is to investigate the PRR involved in the recognition of M. paratuberculosis. Methods used include in vitro stimulation of transfected cell lines, murine macrophages, and human PBMC. M. paratuberculosis stimulated human TLR2 (hTLR2)-Chinese hamster ovary (CHO) cells predominantly and hTLR4-CHO cells modestly. Macrophages from TLR2 and TLR4 knockout mice produced less cytokines compared with controls after stimulation with M. paratuberculosis. TLR4 inhibition in human PBMC reduced cytokine production only after stimulation with live M. paratuberculosis. TLR-induced TNF-alpha, IL-1beta, and IL-10 production is mediated through MyD88, whereas Toll-IL-1R domain-containing adaptor inducing IFN-beta (TRIF) promoted the release of IL-1beta. hNOD2-human embryo kidney (HEK) cells, but not hNOD1-HEK cells, responded to stimulation with M. paratuberculosis. PBMC of individuals homozygous for the 3020insC NOD2 mutation showed a 70% defective cytokine response after stimulation with M. paratuberculosis. These results demonstrate that TLR2, TLR4, and NOD2 are involved in the recognition of M. paratuberculosis by the innate immune system.
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Affiliation(s)
- Gerben Ferwerda
- Department of Internal Medicine and Nijmegen University Center for Infectious Diseases, Radboud University Nijmegen Medical Center, Geert Grooteplein Zuid 8, 6525 GA Nijmegen, The Netherlands
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Schromm AB, Howe J, Ulmer AJ, Wiesmüller KH, Seyberth T, Jung G, Rössle M, Koch MHJ, Gutsmann T, Brandenburg K. Physicochemical and biological analysis of synthetic bacterial lipopeptides: validity of the concept of endotoxic conformation. J Biol Chem 2007; 282:11030-7. [PMID: 17308304 DOI: 10.1074/jbc.m700287200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The importance of the biological function and activity of lipoproteins from the outer or cytoplasmic membranes of Gram-positive and Gram-negative bacteria is being increasingly recognized. It is well established that they are like the endotoxins (lipopolysaccharide (LPS)), which are the main amphiphilic components of the outer membrane of Gram-negative bacteria, potent stimulants of the human innate immune system, and elicit a variety of proinflammatory immune responses. Investigations of synthetic lipopeptides corresponding to N-terminal partial structures of bacterial lipoproteins defined the chemical prerequisites for their biological activity and in particular the number and length of acyl chains and sequence of the peptide part. Here we present experimental data on the biophysical mechanisms underlying lipopeptide bioactivity. Investigation of selected synthetic diacylated and triacylated lipopeptides revealed that the geometry of these molecules (i.e. the molecular conformations and supramolecular aggregate structures) and the preference for membrane intercalation provide an explanation for the biological activities of the different lipopeptides. This refers in particular to the agonistic or antagonistic activity (i.e. their ability to induce cytokines in mononuclear cells or to block this activity, respectively). Biological activity of lipopeptides was hardly affected by the LPS-neutralizing antibiotic polymyxin B, and the biophysical interaction characteristics were found to be in sharp contrast to that of LPS with polymyxin B. The analytical data show that our concept of "endotoxic conformation," originally developed for LPS, can be applied also to the investigated lipopeptide and suggest that the molecular mechanisms of cell activation by amphiphilic molecules are governed by a general principle.
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Affiliation(s)
- Andra B Schromm
- Research Center Borstel, Leibniz Center for Medicine and Biosciences, Department of Immunochemistry and Biochemical Microbiology, Emmy Noether Group of Immunobiophysics, Division of Biophysics, Borstel, Germany.
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