Molecular Recognition of Muramyl Dipeptide Occurs in the Leucine-rich Repeat Domain of Nod2

Lauro, Mackenzie L.; D'Ambrosio, Elizabeth A.; Bahnson, Brian J.; Grimes, Catherine L.

doi:10.1021/acsinfecdis.6b00154

Cited by 43 publications

(74 citation statements)

References 36 publications

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“…MDP is linked to the surface via the C‐1 and the previously established C‐6 position (Figure A), allowing us to directly compare binding affinities for the site of modification. A concentration gradient of Nod2 LRR was applied to the surface and the binding affinities for both compounds were determined. Nod2 LRR binds to 6‐amino MDP with low nanomolar binding affinity (95(±9) n m ) in agreement with the literature (Figure B) .…”

Section: Methodsmentioning

confidence: 99%

“…A concentration gradient of Nod2 LRR was applied to the surface and the binding affinities for both compounds were determined. Nod2 LRR binds to 6‐amino MDP with low nanomolar binding affinity (95(±9) n m ) in agreement with the literature (Figure B) . When ( 1 ) was attached to the surface via the C‐1 position, binding decreased to high nanomolar affinity (700(±100) n m ; Figure C).…”

Section: Methodsmentioning

confidence: 99%

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Synthesis and Application of Methyl N,O‐Hydroxylamine Muramyl Peptides

et al. 2019

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The innate immune system's interaction with bacterial cells plays a pivotal role in a variety of human diseases. Carbohydrate units derived from a component of bacterial cell wall, peptidoglycan (PG), are known to stimulate an immune response. Nonetheless, access to modified late‐stage peptidoglycan intermediates is limited due to their synthetic complexity. A method to rapidly functionalize PG fragments is needed to better understand the natural host–PG interactions. Here methyl N,O‐hydroxylamine linkers are incorporated onto a synthetic PG derivative, muramyl dipeptide (MDP). The modification of MDP maintained the ability to stimulate a nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) immune response dependent on the expression of nucleotide‐binding oligomerization domain‐containing protein 2 (Nod2). Intrigued by this modification's maintenance of biological activity, several applications were explored. Methyl N,O‐hydroxylamine MDP was amendable to N‐hydroxylsuccinimide (NHS) chemistry for bioconjugation to fluorophores as well as a self‐assembled monolayer for Nod2 surface plasmon resonance analysis. Finally, linker incorporation was applicable to larger PG fragments, both enzymatically generated from Escherichia coli or chemically synthesized. This methodology provides rapid access to PG probes in one step and allows for the installation of a variety of chemical handles to advance the molecular understanding of PG and the innate immune system.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Synthesis and Application of Methyl N,O‐Hydroxylamine Muramyl Peptides

et al. 2019

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“…Nucleotide‐binding oligomerization domain protein 2, initially described as a susceptibility gene for inflammatory bowel diseases such as Crohn’s disease, is an intracellular protein LRRs (containing leucine‐rich repeats) similar to those found in TLRs (Toll‐like receptors) [8]. As an intracellular PRR (pathogen recognition receptor), NOD2 perceives bacterial peptidoglycans from gram‐positive and gram‐negative bacteria, through its interaction with MDP (muramyl dipeptide) [9,10]. NOD2 is widely expressed in dendritic cells, macrophages, and at lower levels in intestinal epithelial cells and VSMCs [11].…”

Section: Introductionmentioning

confidence: 99%

Nucleotide‐binding oligomerization domain protein 2 deficiency enhances CHOP expression and plaque necrosis in advanced atherosclerotic lesions

et al. 2020

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Endoplasmic reticulum (ER) stress-induced cell death of vascular smooth muscle cells (VSMCs) is extensively involved in atherosclerotic plaque stabilization. We previously reported that nucleotide-binding oligomerization domain protein 2 (NOD2) participated in vascular homeostasis and tissue injury. However, the role and underlying mechanisms of NOD2 remain unknown in ER stress-induced cell death of VSMC during vascular diseases, including advanced atherosclerosis. Here, we report that NOD2 specifically interacted with ER stress sensor activating transcription factor 6 (ATF6) and suppressed the expression of proapoptotic transcription factor CHOP (C/EBP homologous protein) during ER stress. CHOP-positive cells were increased in neointimal lesions after femoral artery injury in NOD2-deficient mice. In particular, a NOD2 ligand, MDP, and overexpression of NOD2 decreased CHOP expression in wild-type VSMCs. NOD2 interacted with an ER stress sensor molecule, ATF6, and acted as a negative regulator for ATF6 activation and its downstream target molecule, CHOP, that regulates ER stress-induced apoptosis. Moreover, NOD2 deficiency promoted disruption of advanced atherosclerotic lesions and CHOP expression in NOD2 À/À ApoE À/À mice. Our findings indicate an unsuspected critical role for NOD2 in ER stress-induced cell death.Abbreviations ATF6, activating transcription factor 6; CHOP, transcription factor C/EBP homologous protein; ER stress, endoplasmic reticulum stress; ERSE, cis-acting ER stress response element; IREl, inositol requiring protein 1; LRRs, leucine-rich repeats; MDP, muramyl dipeptide; NOD2, nucleotide-binding oligomerization domain protein 2; PERK, protein kinase RNA-like endoplasmic reticulum kinase; PRRs, pattern recognition receptors; TLRs, toll-like receptors; VSMCs, vascular smooth muscle cells; XBP1, X-box binding protein 1.NOD2 regulates ER stress-induced cell death M-Y. Kwon et al.

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“…RNA secreted from bacteria can also induce IFN-␤ production by activation of the cytosolic RIG-I sensor (19). A third possibility is that cell wall components released from the phagosome activated cytoplasmic NOD2 (41). Pore-forming toxins, including pneumolysin, have been suggested to deliver bacterial stimulatory molecules from the phagolysosome to the host cytosol, where interaction with pattern recognition receptors occurs, leading to IFN-␤ production (33,37).…”

Section: Discussionmentioning

confidence: 99%

Intact Pneumococci Trigger Transcription of Interferon-Related Genes in Human Monocytes, while Fragmented, Autolyzed Bacteria Subvert This Response

et al. 2017

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A peculiar trait of pneumococci (Streptococcus pneumoniae) is their propensity to undergo spontaneous lysis during stationary growth due to activation of the enzyme autolysin (LytA), which fragments the peptidoglycan cell wall. The fragments that are generated upon autolysis impair phagocytosis and reduce production of interleukin-12 (IL-12) and gamma interferon (IFN-␥) by human leukocytes in response to intact pneumococci, thereby impeding crucial host defenses. The objective was to identify additional monocyte genes whose transcription is induced by intact pneumococci and subverted by autolyzed bacteria. Monocytes were isolated from healthy blood donors and stimulated for 3 h with UV-inactivated S. pneumoniae (Rx1PLY Ϫ LytA ϩ strain), which is capable of autolyzing, its LytA Ϫ isogenic autolysindeficient mutant, or a mixture of the two (containing twice the initial bacterial concentration). Gene expression was assessed by Illumina microarray, and selected findings were confirmed by reverse transcription-quantitative real-time PCR (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), and flow cytometry. In all, we identified 121 genes that were upregulated to a significantly higher degree by intact than autolyzed pneumococci. These included IFNB1 and a large set of interferon-induced genes, such as IFIT3, RSAD2, CFCL1, and CXCL10 genes, as well as IL12B and CD40 genes. RT-qPCR revealed that transcription of these genes in response to intact pneumococci diminished when autolyzed pneumococci were admixed and that this pattern was independent of pneumolysin. Thus, transcription of interferon-related genes is triggered by intact pneumococci and subverted by fragments generated by spontaneous bacterial autolysis. We suggest that interferon-related pathways are important for elimination of pneumococci and that autolysis contributes to virulence by extinguishing these pathways. KEYWORDS Streptococcus pneumoniae, autolysins, inflammation, interferons Infection by the pneumococcus (Streptococcus pneumoniae) is a leading cause of death in young children worldwide (1). Pneumococci are one of the major causes of pneumonia, sepsis, and meningitis, as well as less severe localized respiratory infections, such as acute otitis media and sinusitis.The major defense against pneumococcal infection is phagocyte-mediated killing, and the most prominent virulence factor is the thick and hydrophilic pneumococcal capsule, which impedes phagocytosis. Another well-recognized virulence factor is pneumolysin, a cytolysin that incorporates into cholesterol-rich eukaryotic cell membranes. When present in high concentrations, it lyses the host cells (2), while lower

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Molecular Recognition of Muramyl Dipeptide Occurs in the Leucine-rich Repeat Domain of Nod2

Cited by 43 publications

References 36 publications

Synthesis and Application of Methyl N,O‐Hydroxylamine Muramyl Peptides

Synthesis and Application of Methyl N,O‐Hydroxylamine Muramyl Peptides

Nucleotide‐binding oligomerization domain protein 2 deficiency enhances CHOP expression and plaque necrosis in advanced atherosclerotic lesions

Intact Pneumococci Trigger Transcription of Interferon-Related Genes in Human Monocytes, while Fragmented, Autolyzed Bacteria Subvert This Response

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