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Posovszky C, Pfalzer V, Lahr G, Niess JH, Klaus J, Mayer B, Debatin KM, von Boyen GBT. Age-of-onset-dependent influence of NOD2 gene variants on disease behaviour and treatment in Crohn's disease. BMC Gastroenterol 2013; 13:77. [PMID: 23635032 PMCID: PMC3659055 DOI: 10.1186/1471-230x-13-77] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 04/26/2013] [Indexed: 02/08/2023] Open
Abstract
Background Influence of genetic variants in the NOD2 gene may play a more important role in disease activity, behaviour and treatment of pediatric- than adult-onset Crohn’s disease (CD). Methods 85 pediatric- and 117 adult-onset CD patients were tested for the three main NOD2 CD-associated variants (p.R702W, p.G908R and p.10007fs) and clinical data of at least two years of follow-up were compared regarding disease behaviour and activity, response to therapy and bone mineral density (BMD). Results Chronic active and moderate to severe course of CD is associated in patients with pediatric-onset (p=0.0001) and NOD2 variant alleles (p=0.0001). In pediatric-onset CD the average PCDAI-Score was significantly higher in patients carrying NOD2 variants (p=0.0008). In addition, underweight during course of the disease (p=0.012) was associated with NOD2 variants. Interestingly, osteoporosis was found more frequently in patients carrying NOD2 variant alleles (p=0.033), especially in pediatric-onset CD patients with homozygous NOD2 variants (p=0.037). Accordingly, low BMD in pediatric-onset CD is associated with a higher PCDAI (p=0.0092), chronic active disease (p=0.0148), underweight at diagnosis (p=0.0271) and during follow-up (p=0.0109). Furthermore, pediatric-onset CD patients with NOD2 variants are more frequently steroid-dependent or refractory (p=0.048) and need long-term immunosuppressive therapy (p=0.0213). Conclusions These data suggests that the presence of any of the main NOD2 variants in CD is associated with osteoporosis and an age of onset dependent influence towards underweight, higher disease activity and a more intensive immunosuppressive therapy. This observation supports the idea for an early intensive treatment strategy in children and adolescent CD patients with NOD2 gene variants.
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Affiliation(s)
- Carsten Posovszky
- Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Eythstr, 24, Ulm, 89075, Germany.
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Schuster C, Gläser R, Fiala C, Eppel W, Harder J, Schröder JM, Elbe-Bürger A. Prenatal human skin expresses the antimicrobial peptide RNase 7. Arch Dermatol Res 2013; 305:545-9. [PMID: 23545750 PMCID: PMC3717166 DOI: 10.1007/s00403-013-1340-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 02/28/2013] [Accepted: 03/18/2013] [Indexed: 11/30/2022]
Abstract
Antimicrobial peptides and proteins (AMPs) play important roles in skin immune defense due to their capacity to inhibit growth of microbes. During intrauterine life, the skin immune system has to acquire the prerequisites to protect the newborn from infection in the hostile environment after birth, which includes the production of skin AMPs. The aim of this study was to analyze the expression of RNase 7, HBD-2/3 and psoriasin during human skin development, thus, providing a deeper insight about the maturity of a fundamental component of the innate immune system. We found low RNase 7 expression levels in the periderm but no expression of HBD-2/3 and psoriasin in first trimester human skin using immunohistochemistry. At the end of the second trimester, RNase 7 is expressed weakly in all epidermal layers with a marked signal in the stratum corneum. HBD-3 and psoriasin are focally expressed while HBD-2 is not detectable. Analysis of supernatants from cultured prenatal skin cells showed that in contrast to adult control, RNase 7 and psoriasin are not found in prenatal skin, suggesting that AMPs are detectable but are not secreted. This study shows the differential expression of AMPs in developing, non-perturbed human prenatal skin. It is conceivable that the combined expression of RNase 7, HBD-3 and psoriasin in fetal skin constitutes a developmental program to exert a broad spectrum of antimicrobial activity to maintain sterility in the amniotic cavity.
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Affiliation(s)
- Christopher Schuster
- Division of Immunology, Allergy and Infectious Diseases (DIAID), Department of Dermatology, Laboratory of Cellular and Molecular Immunobiology of the Skin, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
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Abstract
NOD1 {nucleotide-binding oligomerization domain 1; NLRC [NOD-LRR (leucine-rich repeat) family with CARD (caspase recruitment domain) 1]} and NOD2 (NLRC2) are among the most prominent members of the NLR (NOD-LRR) family –proteins that contain nucleotide-binding NACHT domains and receptor-like LRR domains. With over 20 members identified in humans, NLRs represent important components of the mammalian innate immune system, serving as intracellular receptors for pathogens and for endogenous molecules elaborated by tissue injury. NOD1 and NOD2 proteins operate as microbial sensors through the recognition of specific PG (peptidoglycan) constituents of bacteria. Upon activation, these NLR family members initiate signal transduction mechanisms that include stimulation of NF-κB (nuclear factor-κB), stress kinases, IRFs (interferon regulatory factors) and autophagy. Hereditary polymorphisms in the genes encoding NOD1 and NOD2 have been associated with an increasing number of chronic inflammatory diseases. In fact, potential roles for NOD1 and NOD2 in inflammatory disorders have been revealed by investigations using a series of animal models. In the present review, we describe recent experimental findings associating NOD1 and NOD2 with various autoimmune and chronic inflammatory disorders, and we discuss prospects for development of novel therapeutics targeting these NLR family proteins.
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104
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Antimicrobial Human β-Defensins in the Colon and Their Role in Infectious and Non-Infectious Diseases. Pathogens 2013; 2:177-92. [PMID: 25436887 PMCID: PMC4235710 DOI: 10.3390/pathogens2010177] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 03/01/2013] [Accepted: 03/10/2013] [Indexed: 01/02/2023] Open
Abstract
β-defensins are small cationic antimicrobial peptides secreted by diverse cell types including colonic epithelial cells. Human β-defensins form an essential component of the intestinal lumen in innate immunity. The defensive mechanisms of β-defensins include binding to negatively charged microbial membranes that cause cell death and chemoattraction of immune cells. The antimicrobial activity of β-defensin is well reported in vitro against several enteric pathogens and in non-infectious processes such as inflammatory bowel diseases, which alters β-defensin production. However, the role of β-defensin in vivo in its interaction with other immune components in host defense against bacteria, viruses and parasites with more complex membranes is still not well known. This review focuses on the latest findings regarding the role of β-defensin in relevant human infectious and non-infectious diseases of the colonic mucosa. In addition, we summarize the most significant aspects of β-defensin and its antimicrobial role in a variety of disease processes.
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105
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Biswas A, Kobayashi KS. Regulation of intestinal microbiota by the NLR protein family. Int Immunol 2013; 25:207-14. [PMID: 23325116 DOI: 10.1093/intimm/dxs116] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The human intestine harbors a diverse microbial community consisting of a large number of bacteria and other micro-organisms that have co-evolved with the host intestinal immune system. During this process, microbiota and the host immune system shape one another by various mechanisms to achieve a successful symbiotic relationship. An increasing amount of evidence suggests that dysbiosis--the breakdown of such harmonized colonization--may result in infectious and inflammatory disorders, and recent advances in our studies indicate that receptors such as Toll-like receptors and NLR (nucleotide-binding oligomerization domain-like receptor; or nucleotide-binding domain- and leucine-rich repeat-containing receptor) proteins that detect micro-organisms and their products play a critical role in maintaining intestinal homeostasis. In this review, we summarize the role of NLR proteins in the regulation of intestinal microbiota. NLR proteins belong to a diverse family of cytoplasmic microbial sensors, mutations of which are involved in various disorders, including inflammatory bowel diseases. Understanding of the different roles of NLR family proteins in the intestine is, therefore, an important step towards the development of therapeutics against digestive diseases.
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Affiliation(s)
- Amlan Biswas
- Department of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, TX 77843, USA
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106
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RNAi screening identifies mediators of NOD2 signaling: implications for spatial specificity of MDP recognition. Proc Natl Acad Sci U S A 2012; 109:21426-31. [PMID: 23213202 DOI: 10.1073/pnas.1209673109] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The intracellular nucleotide-binding oligomerization domain-2 (NOD2) receptor detects bacteria-derived muramyl dipeptide (MDP) and activates the transcription factor NF-κB. Here we describe the regulatome of NOD2 signaling using a systematic RNAi screen. Using three consecutive screens, we identified a set of 20 positive NF-κB regulators including the known pathway members RIPK2, RELA, and BIRC4 (XIAP) as well as FRMPD2 (FERM and PDZ domain-containing 2). FRMPD2 interacts with NOD2 via leucine-rich repeats and forms a complex with the membrane-associated protein ERBB2IP. We demonstrate that FRMPD2 spatially assembles the NOD2-signaling complex, hereby restricting NOD2-mediated immune responses to the basolateral compartment of polarized intestinal epithelial cells. We show that genetic truncation of the NOD2 leucine-rich repeat domain, which is associated with Crohn disease, impairs the interaction with FRMPD2, and that intestinal inflammation leads to down-regulation of FRMPD2. These results suggest a structural mechanism for how polarity of epithelial cells acts on intestinal NOD-like receptor signaling to mediate spatial specificity of bacterial recognition and control of immune responses.
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107
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Inflammatory bowel disease: an impaired barrier disease. Langenbecks Arch Surg 2012; 398:1-12. [PMID: 23160753 DOI: 10.1007/s00423-012-1030-9] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 11/01/2012] [Indexed: 12/19/2022]
Abstract
BACKGROUND The intestinal barrier is a delicate structure composed of a single layer of epithelial cells, the mucus, commensal bacteria, immune cells, and antibodies. Furthermore, a wealth of antimicrobial peptides (AMPs) can be found in the mucus and defend the mucosa. Different lines of investigations now point to a prominent pathophysiological role of defensins, an important family of AMPs, in the pathogenesis of inflammatory bowel disease and, particularly, in small intestinal Crohn's disease. PURPOSE In this review, we introduce the different antimicrobial peptides of the intestinal mucosa and describe their function, their expression pattern along the gastrointestinal tract, and their spatial relationship to the mucus layer. We then focus on the alterations found in inflammatory bowel disease. Small intestinal Crohn's disease (CD) is closely linked to defects in Paneth cells (specialized secretory epithelial cells at the bottom crypts) which secrete α-defensin human defensin (HD)-5 in huge quantities in healthy individuals. Decreased expression of these antimicrobial peptides is found in ileal CD, and single nucleotide polymorphisms with the highest linkage to CD affect genes involved in Paneth cell biology and defensin secretion. Additionally, antimicrobial peptides have a role in ulcerative colitis, where the depleted mucus layer cannot fulfill its crucial function of binding defensins and other AMPs to their proper site of action. CONCLUSION Inflammatory bowel disease arises when the mucosal barrier is compromised in its defense against challenges from the intestinal microbiota. In ileal CD, a strong association can be found between diminished expression or defective function of defensins and the advent of intestinal inflammation.
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Chassin C, Hempel C, Stockinger S, Dupont A, Kübler JF, Wedemeyer J, Vandewalle A, Hornef MW. MicroRNA-146a-mediated downregulation of IRAK1 protects mouse and human small intestine against ischemia/reperfusion injury. EMBO Mol Med 2012; 4:1308-19. [PMID: 23143987 PMCID: PMC3531605 DOI: 10.1002/emmm.201201298] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 09/21/2012] [Accepted: 09/25/2012] [Indexed: 01/28/2023] Open
Abstract
Intestinal ischemia/reperfusion (I/R) injury causes inflammation and tissue damage and is associated with high morbidity and mortality. Uncontrolled activation of the innate immune system through toll-like receptors (Tlr) plays a key role in I/R-mediated tissue damage but the underlying mechanisms have not been fully resolved. Here, we identify post-transcriptional upregulation of the essential Tlr signalling molecule interleukin 1 receptor-associated kinase (Irak) 1 as the causative mechanism for post-ischemic immune hyper-responsiveness of intestinal epithelial cells. Increased Irak1 protein levels enhanced epithelial ligand responsiveness, chemokine secretion, apoptosis and mucosal barrier disruption in an experimental intestinal I/R model using wild-type, Irak1−/− and Tlr4−/− mice and ischemic human intestinal tissue. Irak1 accumulation under hypoxic conditions was associated with reduced K48 ubiquitination and enhanced Senp1-mediated deSUMOylation of Irak1. Importantly, administration of microRNA (miR)-146a or induction of miR-146a by the phytochemical diindolylmethane controlled Irak1 upregulation and prevented immune hyper-responsiveness in mouse and human tissue. These findings indicate that Irak1 accumulation triggers I/R-induced epithelial immune hyper-responsiveness and suggest that the induction of miR-146a offers a promising strategy to prevent I/R tissue injury.
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Affiliation(s)
- Cécilia Chassin
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany.
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109
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Moreira LO, Zamboni DS. NOD1 and NOD2 Signaling in Infection and Inflammation. Front Immunol 2012; 3:328. [PMID: 23162548 PMCID: PMC3492658 DOI: 10.3389/fimmu.2012.00328] [Citation(s) in RCA: 190] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 10/17/2012] [Indexed: 12/12/2022] Open
Abstract
Sensing intracellular pathogens is a process mediated by innate immune cells that is crucial for the induction of inflammatory processes and effective adaptive immune responses against pathogenic microbes. NOD-like receptors (NLRs) comprise a family of intracellular pattern recognition receptors that are important for the recognition of damage and microbial-associated molecular patterns. NOD1 and NOD2 are specialized NLRs that participate in the recognition of a subset of pathogenic microorganisms that are able to invade and multiply intracellularly. Once activated, these molecules trigger intracellular signaling pathways that lead to the activation of transcriptional responses culminating in the expression of a subset of inflammatory genes. In this review, we will focus on the role of NOD1 and NOD2 in the recognition and response to intracellular pathogens, including Gram-positive and Gram-negative bacteria, and on their ability to signal in response to non-peptidoglycan-containing pathogens, such as viruses and protozoan parasites.
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Affiliation(s)
- Lilian O Moreira
- Faculdade de Farmácia, Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
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110
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Harder J, Schröder JM, Gläser R. The skin surface as antimicrobial barrier: present concepts and future outlooks. Exp Dermatol 2012; 22:1-5. [DOI: 10.1111/exd.12046] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2012] [Indexed: 12/12/2022]
Affiliation(s)
- Jürgen Harder
- Department of Dermatology; University Hospital of Schleswig-Holstein; Kiel; Germany
| | | | - Regine Gläser
- Department of Dermatology; University Hospital of Schleswig-Holstein; Kiel; Germany
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111
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Daddaoua A, Martínez-Plata E, Ortega-González M, Ocón B, Aranda CJ, Zarzuelo A, Suárez MD, de Medina FS, Martínez-Augustin O. The nutritional supplement Active Hexose Correlated Compound (AHCC) has direct immunomodulatory actions on intestinal epithelial cells and macrophages involving TLR/MyD88 and NF-κB/MAPK activation. Food Chem 2012. [PMID: 23194525 DOI: 10.1016/j.foodchem.2012.09.039] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Active Hexose Correlated Compound (AHCC) is an immunostimulatory nutritional supplement. AHCC effects and mechanism of action on intestinal epithelial cells or monocytes are poorly described. AHCC was added to the culture medium of intestinal epithelial cells (IEC18 and HT29 cells) and monocytes (THP-1 cells) and assessed the secretion of proinflammatory cytokines by ELISA. Inhibitors of NFκB and MAPKs were used to study signal transduction pathways while TLR4 and MyD88 were silenced in IEC18 cells using shRNA. It was found that AHCC induced GROα and MCP1 secretion in IEC18 and IL-8 in HT29 cells. These effects depended on NFκB activation, and partly on MAPKs activation and on the presence of MyD88 and TLR4. In THP-1 cells AHCC evoked IL-8, IL-1β and TNF-α secretion. The induction of IL-8 depended on JNK and NFκB activation. Therefore, AHCC exerts immunostimulatory effects on intestinal epithelial cells and monocytes involving TLR4/MyD88 and NFκB/MAPK signal transduction pathways.
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Affiliation(s)
- Abdelali Daddaoua
- Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, C/ Profesor Albareda 1, E-18008 Granada, Spain
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112
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Kang MJ, Heo SK, Song EJ, Kim DJ, Han SY, Han JH, Kim BY, Park JH. Activation of Nod1 and Nod2 induces innate immune responses of prostate epithelial cells. Prostate 2012; 72:1351-8. [PMID: 22228081 DOI: 10.1002/pros.22483] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 12/12/2011] [Indexed: 12/21/2022]
Abstract
BACKGROUND Nod1 and Nod2 are cytosolic receptors which are responsible for sensing bacterial peptidoglycan derivatives. In this study, we determined whether Nod1 and Nod2 are involved in the innate immune responses of prostate epithelial cells. METHODS The expression of Nod1 and Nod2 was examined by RT-PCR and immunohistochemistry. ELISA was performed to determine the production of cytokines/chemokines. Activation of NF-κB and MAPK was examined using western blot analysis. RESULTS The Nod1 gene was distinctly expressed in all tested cells including DU145, PC3, and TRAMP-C2 cells, whereas Nod2 expression was weak. Both Nod1 and Nod2 proteins were expressed in normal mouse prostate epithelia with difference of expression levels. Tri-DAP (Nod1 agonist), but not MDP (Nod2), increased the production of IL-8 (or KC) and IL-6 in prostate epithelial cells. Tri-DAP and MDP could upregulate the gene expression of COX-2 and activate NF-κB and MAPK. In addition, Tri-DAP and MDP synergized with TLR agonists to induce the production of IL-8/KC or IL-6 in PC3 and TRAMP-C2 cells. We finally showed that Nod1 and Nod2 were also expressed in a wide range of prostate lesions including prostate intraepithelial neoplasm (PIN), phyllodes-like tumor, and adenocarcinoma in TRAMP (transgenic adenocarcinoma of the mouse prostate) mice, even though the expression level of Nod1 and Nod2 was different. CONCLUSION These results indicate that Nod1 and Nod2 may play important roles in the innate immune response of prostate epithelial cells and the development and progression of prostate cancer.
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Affiliation(s)
- Min-Jung Kang
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon 302-711, Korea
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113
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Regulation of antimicrobial peptide gene expression by nutrients and by-products of microbial metabolism. Eur J Nutr 2012; 51:899-907. [PMID: 22797470 DOI: 10.1007/s00394-012-0415-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 06/27/2012] [Indexed: 12/22/2022]
Abstract
BACKGROUND Antimicrobial peptides (AMPs) are synthesized and secreted by immune and epithelial cells that are constantly exposed to environmental microbes. AMPs are essential for barrier defense, and deficiencies lead to increased susceptibility to infection. In addition to their ability to disrupt the integrity of bacterial, viral and fungal membranes, AMPs bind lipopolysaccharides, act as chemoattractants for immune cells and bind to cellular receptors and modulate the expression of cytokines and chemokines. These additional biological activities may explain the role of AMPs in inflammatory diseases and cancer. Modulating the endogenous expression of AMPs offers potential therapeutic treatments for infection and disease. METHODS The present review examines the published data from both in vitro and in vivo studies reporting the effects of nutrients and by-products of microbial metabolism on the expression of antimicrobial peptide genes in order to highlight an emerging appreciation for the role of dietary compounds in modulating the innate immune response. RESULTS Vitamins A and D, dietary histone deacetylases and by-products of intestinal microbial metabolism (butyrate and secondary bile acids) have been found to regulate the expression of AMPs in humans. Vitamin D deficiency correlates with increased susceptibility to infection, and supplementation studies indicate an improvement in defense against infection. Animal and human clinical studies with butyrate indicate that increasing expression of AMPs in the colon protects against infection. CONCLUSION These findings suggest that diet and/or consumption of nutritional supplements may be used to improve and/or modulate immune function. In addition, by-products of gut microbe metabolism could be important for communicating with intestinal epithelial and immune cells, thus affecting the expression of AMPs. This interaction may help establish a mucosal barrier to prevent invasion of the intestinal epithelium by either mutualistic or pathogenic microorganisms.
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114
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Hill DR, Kessler SP, Rho HK, Cowman MK, de la Motte CA. Specific-sized hyaluronan fragments promote expression of human β-defensin 2 in intestinal epithelium. J Biol Chem 2012; 287:30610-24. [PMID: 22761444 DOI: 10.1074/jbc.m112.356238] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hyaluronan (HA) is a glycosaminoglycan polymer found in the extracellular matrix of virtually all mammalian tissues. Recent work has suggested a role for small, fragmented HA polymers in initiating innate defense responses in immune cells, endothelium, and epidermis through interaction with innate molecular pattern recognition receptors, such as TLR4. Despite these advances, little is known regarding the effect of fragmented HA at the intestinal epithelium, where numerous pattern recognition receptors act as sentinels of an innate defense response that maintains epithelial barrier integrity in the presence of abundant and diverse microbial challenges. Here we report that HA fragments promote expression of the innate antimicrobial peptide human β-defensin 2 (HβD2) in intestinal epithelial cells. Treatment of HT-29 colonic epithelial cells with HA fragment preparations resulted in time- and dose-dependent up-regulated expression of HβD2 protein in a fragment size-specific manner, with 35-kDa HA fragment preparations emerging as the most potent inducers of intracellular HβD2. Furthermore, oral administration of specific-sized HA fragments promotes the expression of an HβD2 ortholog in the colonic epithelium of both wild-type and CD44-deficient mice but not in TLR4-deficient mice. Together, our observations suggest that a highly size-specific, TLR4-dependent, innate defense response to fragmented HA contributes to intestinal epithelium barrier defense through the induction of intracellular HβD2 protein.
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Affiliation(s)
- David R Hill
- Department of Molecular Medicine, Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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115
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Pathogen recognition and activation of the innate immune response in zebrafish. Adv Hematol 2012; 2012:159807. [PMID: 22811714 PMCID: PMC3395205 DOI: 10.1155/2012/159807] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 04/22/2012] [Indexed: 12/28/2022] Open
Abstract
The zebrafish has proven itself as an excellent model to study vertebrate innate immunity. It presents us with possibilities for in vivo imaging of host-pathogen interactions which are unparalleled in mammalian model systems. In addition, its suitability for genetic approaches is providing new insights on the mechanisms underlying the innate immune response. Here, we review the pattern recognition receptors that identify invading microbes, as well as the innate immune effector mechanisms that they activate in zebrafish embryos. We compare the current knowledge about these processes in mammalian models and zebrafish and discuss recent studies using zebrafish infection models that have advanced our general understanding of the innate immune system. Furthermore, we use transcriptome analysis of zebrafish infected with E. tarda, S. typhimurium, and M. marinum to visualize the gene expression profiles resulting from these infections. Our data illustrate that the two acute disease-causing pathogens, E. tarda and S. typhimurium, elicit a highly similar proinflammatory gene induction profile, while the chronic disease-causing pathogen, M. marinum, induces a weaker and delayed innate immune response.
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116
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Juárez E, Carranza C, Hernández-Sánchez F, León-Contreras JC, Hernández-Pando R, Escobedo D, Torres M, Sada E. NOD2 enhances the innate response of alveolar macrophages to Mycobacterium tuberculosis in humans. Eur J Immunol 2012; 42:880-9. [PMID: 22531915 DOI: 10.1002/eji.201142105] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A role for the nucleotide-binding oligomerization domain 2 (NOD2) receptor in pulmonary innate immune responses has recently been explored. In the present study, we investigated the role that NOD2 plays in human alveolar macrophage innate responses and determined its involvement in the response to infection with virulent Mycobacterium tuberculosis. Our results showed that NOD2 was expressed in human alveolar macrophages, and significant amounts of IL-1β, IL-6, and TNF-α were produced upon ligand recognition with muramyldipeptide (MDP). NOD2 ligation induced the transcription and protein expression of the antimicrobial peptide LL37 and the autophagy enzyme IRGM in alveolar macrophages, demonstrating a novel function for this receptor in these cells. MDP treatment of alveolar macrophages improved the intracellular growth control of virulent M. tuberculosis; this was associated with a significant release of TNF-α and IL-6 and overexpression of bactericidal LL37. In addition, the autophagy proteins IRGM, LC3 and ATG16L1 were recruited to the bacteria-containing autophagosome after treatment with MDP. In conclusion, our results suggest that NOD2 can modulate the innate immune response of alveolar macrophages and play a role in the initial control of respiratory M. tuberculosis infections.
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Affiliation(s)
- Esmeralda Juárez
- Department of Microbiology, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, México City, México
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Kopfnagel V, Wittmann M, Werfel T. An AIM2 inflammasome is active in human keratinocytes : Response to letter from Dombrowski et al.: Comment on Kopfnagel et al. Exp Dermatol. 2011 Dec; 20(12):1027-9. Exp Dermatol 2012. [DOI: 10.1111/j.1600-0625.2012.01512.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Verena Kopfnagel
- Division of Immunodermatology and Allergy Research; Department of Dermatology and Allergy; Hannover Medical School; Hannover; Germany
| | | | - Thomas Werfel
- Division of Immunodermatology and Allergy Research; Department of Dermatology and Allergy; Hannover Medical School; Hannover; Germany
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118
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Dössel J, Meyer-Hoffert U, Schröder JM, Gerstel U. Pseudomonas aeruginosa-derived rhamnolipids subvert the host innate immune response through manipulation of the human beta-defensin-2 expression. Cell Microbiol 2012; 14:1364-75. [PMID: 22500651 DOI: 10.1111/j.1462-5822.2012.01801.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Pseudomonas aeruginosa is a well-known cause of infections especially in compromised patients. To neutralize this pathogen, the expression of antimicrobial factors in epithelial cells is crucial. In particular the human beta-defensin hBD-2 is especially active against P. aeruginosa. In this study, we identified rhamnolipids in P. aeruginosa culture supernatants that are able to prevent the pathogen-induced hBD-2 response in keratinocytes. The presence of rhamnolipids within the host cells and inhibition assays suggest that calcium-regulated pathways and protein kinase C activation are impaired by rhamnolipids. In consequence, the induction of hBD-2 in keratinocytes by P. aeruginosa-derived flagellin as well as the host's own hBD-2 mediator interleukin IL-1β is inhibited. Strikingly, rhamnolipids did not affect the release of the proinflammatory mediator interleukin IL-8 by flagellin. Thus, in addition to their function in establishment and persistence of P. aeruginosa infections, rhamnolipids can be engaged by P. aeruginosa for a targeted attenuation of the innate immunity to manage its survival and colonization on compromised epithelia.
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Affiliation(s)
- Jomtje Dössel
- Department of Dermatology, University Hospital Schleswig-Holstein, D-24105 Kiel, Germany
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Kesting MR, Stoeckelhuber M, Kuppek A, Hasler R, Rohleder N, Wolff KD, Nieberler M. Human β-defensins and psoriasin/S100A7 expression in salivary glands: anti-oncogenic molecules for potential therapeutic approaches. BioDrugs 2012; 26:33-42. [PMID: 22149099 DOI: 10.2165/11597570-000000000-00000] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Host defence peptides (HDPs), including human β-defensins (hBDs) and psoriasin/S100A7, exert antimicrobial and immunoregulatory functions of the innate defense system. In addition to these functions, the search for cancer biomarkers has identified HDPs as playing a potential role in both tumor suppression and oncogenesis. Although HDPs are highly expressed in salivary glands, their role as molecules for potential diagnostic and therapeutic approaches has not yet been analyzed. OBJECTIVE The aim of the present study was to investigate whether expression levels of putative pro- or anti-oncogenic hBDs, including hBD-1, -2, -3, and psoriasin/S100A7, are altered in salivary gland tumor tissue as potential targets for molecular-based therapeutic approaches. METHODS We analyzed the expression levels of hBD-1, -2, -3, and psoriasin/S100A7 by quantitative real-time polymerase chain reaction (qrt-PCR) and immunohistochemistry in a case control study by comparing salivary gland tumor samples relative to healthy control specimens from 58 patients. Expression level analysis of hBD-1, -2, -3, and psoriasin/S100A7 by qrt-PCR was normalized to the endogenous 18S rRNA expression levels. RESULTS The results demonstrate the significant downregulation of hBD-1 (p < 0.001), hBD-2 (p = 0.003), hBD-3 (p = 0.002), and psoriasin/S100A7 (p = 0.003) mRNA in human salivary gland tumors compared with healthy control specimens. Protein expression levels of hBD-1, -2, -3, and psoriasin/S100A7 in salivary gland tumor tissue were strongly reduced compared with healthy control specimens. CONCLUSION The data indicates a putative role of the innate defense system in salivary gland tumor formation. The identification of immunoregulatory molecules as diagnostic biomarkers or therapeutic targets could provide new approaches for molecular-based diagnostic and therapeutic support to treat salivary gland tumors as well as other malignancies. We suggest that HDPs should be taken into consideration for use in molecular-based therapeutic approaches.
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Affiliation(s)
- Marco R Kesting
- Department of Oral and Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
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Johannessen M, Sollid JE, Hanssen AM. Host- and microbe determinants that may influence the success of S. aureus colonization. Front Cell Infect Microbiol 2012; 2:56. [PMID: 22919647 PMCID: PMC3417514 DOI: 10.3389/fcimb.2012.00056] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 04/10/2012] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus may cause serious skin and soft tissue infections, deep abscesses, endocarditis, osteomyelitis, pneumonia, and sepsis. S. aureus persistently colonizes 25–30% of the adult human population, and S. aureus carriers have an increased risk for infections caused by the bacterium. The major site of colonization is the nose, i.e., the vestibulum nasi, which is covered with ordinary skin and hair follicles. Several host and microbe determinants are assumed to be associated with colonization. These include the presence and expression level of bacterial adhesins, which can adhere to various proteins in the extracellular matrix or on the cellular surface of human skin. The host expresses several antimicrobial peptides and lipids. The level of β-defensin 3, free sphingosine, and cis-6-hexadecenoic acid are found to be associated with nasal carriage of S. aureus. Other host factors are certain polymorphisms in Toll-like receptor 2, mannose-binding lectin, C-reactive protein, glucocorticoid-, and vitamin D receptor. Additional putative determinants for carriage include genetic variation and expression of microbial surface components recognizing adhesive matrix molecules and their interaction partners, as well as variation among humans in the ability of recognizing and responding appropriately to the bacteria. Moreover, the available microflora may influence the success of S. aureus colonization. In conclusion, colonization is a complex interplay between the bacteria and its host. Several bacterial and host factors are involved, and an increased molecular understanding of these are needed.
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Affiliation(s)
- Mona Johannessen
- Research Group of Host-Microbe Interaction, Department of Medical Biology, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.
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121
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Swain B, Basu M, Samanta M. Molecular cloning and characterization of nucleotide binding and oligomerization domain-1 (NOD1) receptor in the Indian Major Carp, rohu (Labeo rohita), and analysis of its inductive expression and down-stream signalling molecules following ligands exposure and Gram-negative bacterial infections. FISH & SHELLFISH IMMUNOLOGY 2012; 32:899-908. [PMID: 22530240 DOI: 10.1016/j.fsi.2012.02.018] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Nucleotide binding and oligomerization domain-1 (NOD1) is a cytoplasmic pattern recognition receptor (PRR), and is a member of the NOD-like receptor (NLR) family. It senses a wide range of bacteria and viruses or their products, and plays a key role in inducing innate immunity. In this report, NOD1 gene was cloned and characterized in rohu (Labeo rohita), a fish species of highest commercial importance in the Indian subcontinent. The full-length rohu NOD1 (rNOD1) cDNA comprised of 3168 bp with a single open reading frame (ORF) of 2814 bp, encoding a polypeptide of 937 amino acids (aa) with an estimated molecular mass of 106.13 kDa. Structurally, it comprised of one caspase recruitment domain (CARD) at N-terminal, seven leucine rich repeat (LRR) regions at C-terminal and one NACHT domain in between N and C-terminals. Phylogenetically, rNOD1 was closely related to grass carp NOD1 (gcNOD1), and exhibited significant similarity (95.8%) and identity (91.0%) in their amino acids. Ontogenic expression analysis of rNOD1 and its associated down-stream signaling molecule RICK (receptor interacting serine–threonine kinase) by quantitative real-time PCR (qRT-PCR) revealed their constitutive expression in all embryonic developmental stages. Basal expression analysis of rNOD1 showed its wide range of expression in all examined tissues, highest was in spleen and the lowest was in blood. Inductive expression of rNOD1 was observed following LPS and poly I:C exposure, and Aeromonas hydrophila, Edwardsiella tarda and Shigella flexneri infections. Expression of RICK in various organs was significantly enhanced by ligands exposure and bacterial infections, and was correlated with the inductive expression of rNOD1. Together, these findings highlighted the important role of NOD1 in fish in response to pathogenic invasion.
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Affiliation(s)
- Banikalyan Swain
- Fish Health Management Division, Central Institute of Freshwater Aquaculture (CIFA), Bhubaneswar, Orissa, India
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Abstract
The pathogenetic mechanisms that cause the two types of inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC), are still under investigation. Nevertheless, there is broad agreement that luminal microbes are of particular relevance in the development of these conditions. In recent years, increasing evidence has shown that defects in the innate immunity are at the centre of both types of IBD. The innate intestinal barrier is provided by the epithelium which secretes antimicrobial peptides (so-called defensins) that are retained in the mucus layer. In ileal CD, the alpha-defensins are lacking owing to several Paneth cell defects. In colonic CD, the expression of beta-defensins is inadequate. This may be related to downregulation of the transcription factor peroxisome proliferator-activated receptor-gamma and in some cohorts is associated with a reduced HBD2 gene copy number. In UC, the mucus layer, which protects the host from the enormous amounts of luminal microbes, is defective. This is accompanied by an insufficient differentiation from intestinal stem cells towards goblet cells. All these disturbances in the gut barrier shift the balance from epithelial defence towards bacterial offence. The current treatment for CD and UC is based on suppression of this secondary inflammatory process. In future, patients may benefit from new therapeutic approaches stimulating the protective innate immune system.
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Affiliation(s)
- M Gersemann
- Department of Internal Medicine I, Robert Bosch Hospital, Stuttgart Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart
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de Koning HD, Simon A, Zeeuwen PLJM, Schalkwijk J. Pattern recognition receptors in infectious skin diseases. Microbes Infect 2012; 14:881-93. [PMID: 22516809 DOI: 10.1016/j.micinf.2012.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 03/15/2012] [Accepted: 03/16/2012] [Indexed: 12/27/2022]
Abstract
During the last decade, multiple pattern recognition receptors (PRRs) have been identified. These are involved in the innate immune response against a plethora of pathogens. However, PRR functioning can also be detrimental, even during infections. This review discusses the current knowledge on PRRs that recognize dermatotropic pathogens, and potential therapeutical implications.
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Affiliation(s)
- Heleen D de Koning
- Department of Dermatology, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB, The Netherlands.
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Abstract
Vitamin D has emerged as a pleiotropic regulator of human physiology, and recent work has revealed that it has several roles in control of human immune system function. Vitamin D was originally characterized for its role in calcium homeostasis, and the active form, 1,25-dihydroxyvitamin D (1,25D), can be produced in the kidney by 1α-hydroxylation of circulating 25-hydroxyvitamin D catalyzed by the enzyme CYP27B1. Renal CYP27B1 expression is regulated by calcium regulatory inputs, and 1,25D produced in the kidney was thought to function largely as an endocrine hormone. However, it is now clear that CYP27B1 is expressed in numerous tissues, and that 1,25D acts at several sites in the body in an intracrine or paracrine manner. In particular, both CYP27B1 and the vitamin D receptor (VDR) are expressed in several cell types in the immune system, where CYP27B1 production is controlled by a number of immune-specific inputs. Recent research has opened several windows on the molecular mechanisms by which 1,25D signaling regulates both innate and adaptive immune responses in humans. Moreover, intervention trials are beginning to provide evidence that vitamin D supplementation can bolster clinical responses to infection. This review will discuss recent developments in our understanding of how immune signaling controls local vitamin D metabolism and how, in turn, the 1,25D-bound VDR modulates immune system function. A particular emphasis will be placed on the interplay between vitamin D signaling and signaling through different classes of pattern recognition receptors in the production of antimicrobial peptides during innate immune responses to microbial infection.
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Affiliation(s)
- John H White
- Department of Physiology, McGill University, McIntyre Bldg., Rm. 1112, 3655 Drummond St, Montreal, QC, H3G 1Y6, Canada.
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Importance of NOD2/CARD15 gene variants for susceptibility to and outcome of sepsis in Turkish children. Pediatr Crit Care Med 2012; 13:e73-7. [PMID: 21460759 DOI: 10.1097/pcc.0b013e3182191c2e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Severe sepsis remains a leading cause of morbidity and mortality in children. Given the link to pathogenesis, polymorphisms in genes involved in infection and inflammation may influence the outcomes in patients with sepsis and septic shock. The role of mutations within the innate immunity receptor NOD2/CARD15 has recently been demonstrated as a risk factor for bacteremia and mortality in adult patients with sepsis. The aim of this study was to evaluate the role of mutations of the NOD2/CARD15 gene in pediatric patients with sepsis. DESIGN Prospective cohort study. SETTING A tertiary care, ten-bed, pediatric intensive care unit. PATIENTS One hundred twenty-eight patients with sepsis admitted to the pediatric intensive care unit and healthy control group were included. INTERVENTIONS Venous blood from the children with sepsis and healthy controls was collected to investigate common polymorphisms (Arg702Trp, Gly908Arg, Leu1007fsincC) within the NOD2/CARD15 gene. Standard polymerase chain reaction restriction fragment length polymorphism technique was used to determine NOD2/CARD15 gene polymorphism. MEASUREMENT AND MAIN RESULTS R702W, G908R, and Leu1007fsinsC variants in the NOD2/CARD15 gene were determined as significant risk factors associated with susceptibility to sepsis (p = .025, p = .031, p = .014, respectively). Sepsis-related mortality was increased in children carrying the Leu1007fsinsC variant (p = .041). CONCLUSIONS The present article is the first report of clinical implications of NOD2/CARD15 gene variants in children with sepsis. Our findings suggest that common polymorphisms in the NOD2/CARD15 gene may play a major role in susceptibility to sepsis and the outcome of sepsis in children.
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Langhorst J, Choi KE. The role of human defensins in gastrointestinal diseases. Expert Rev Clin Immunol 2012; 7:779-87. [PMID: 22014019 DOI: 10.1586/eci.11.62] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In clarifying the pathogenesis of inflammatory bowel diseases, a dysregulation of the adaptive immune function was the main focus of research in the last decade. With increasing knowledge of antimicrobial peptides, a primary disturbed barrier function and the system of innate immunity has recently received increasing attention. Contrary to the common understanding of irritable bowel syndrome as a functional disorder, there is first evidence for an involvement of innate immunity for this condition. Peptides with high relevance seem to be the class of human defensins. This article will thus discuss current advances in immunologic research of inflammatory bowel disease and irritable bowel syndrome, focusing on defensins and their possible role as biomarkers of these diseases.
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Affiliation(s)
- Jost Langhorst
- Integrative Gastroenterology, Department of Integrative and Internal Medicine, Kliniken Essen-Mitte, University of Duisburg-Essen, Knappschafts Krankenhaus, Am Deimelsberg 34a, 45276 Essen, Germany.
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127
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Abstract
It is now clear that the epidermis has an active role in local immune responses in the skin. Keratinocytes are involved early in inflammation by providing first-line innate mechanisms and, in addition, can contribute to adaptive immune responses that may be associated with clinical disease. Moreover, keratinocytes are capable of enhancing and shaping the outcome of inflammation in response to stimuli and promoting particular types of immune bias. Through understanding the underlying mechanisms, the role of keratinocytes in disease pathogenesis will be further defined, which is likely to lead to the identification of potential targets for prophylactic or therapeutic intervention.
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Affiliation(s)
- Danuta Gutowska-Owsiak
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
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128
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Hering NA, Fromm M, Schulzke JD. Determinants of colonic barrier function in inflammatory bowel disease and potential therapeutics. J Physiol 2012; 590:1035-44. [PMID: 22219336 DOI: 10.1113/jphysiol.2011.224568] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Intestinal barrier dysfunction is a main feature of the inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis. Leak flux diarrhoea and a facilitated uptake of noxious antigens are the two consequences resulting from an impaired epithelial barrier. Barrier perturbations in IBD comprise alterations in epithelial tight junctions (TJ), i.e. a reduced number of horizontal TJ strands and an altered TJ protein expression and subcellular distribution. Moreover, increased incidence of apoptotic events as well as erosions and ulcerations can add to that leakiness. These barrier defects are attributed to enhanced activity of pro-inflammatory cytokines like TNFα, INFγ, IL-1β and IL-13, which are highly expressed in the chronically inflamed intestine. Although the aetiology of IBD is far from being clear, chronic inflammation is believed to result from an inadequate immune response as a consequence of genetic predisposition as well as changes in, and altered responses to, the intestinal microbiota. On the other hand, an insufficient mucosal response to bacterial stimuli results in an insufficient immune response towards intestinal pathogens. However, detailed characterization of barrier defects offers the opportunity to consider and test therapeutic interventions. Beside cytokine antagonists, different plant compounds and probiotics have been shown to stabilize the barrier function by affecting TJ protein expression and distribution.
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Affiliation(s)
- Nina A Hering
- Department of Gastroenterology, Division of Nutritional Medicine, Charité, Campus Benjamin Franklin, Berlin, Germany
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Swain B, Basu M, Sahoo BR, Maiti NK, Routray P, Eknath AE, Samanta M. Molecular characterization of nucleotide binding and oligomerization domain (NOD)-2, analysis of its inductive expression and down-stream signaling following ligands exposure and bacterial infection in rohu (Labeo rohita). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2012; 36:93-103. [PMID: 21767564 DOI: 10.1016/j.dci.2011.06.018] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 06/16/2011] [Accepted: 06/17/2011] [Indexed: 05/31/2023]
Abstract
Nucleotide-binding and oligomerization domain (NOD)-2 is a cytoplasmic pattern recognition receptor (PRR) and is a member of NOD like receptor (NLR) family. It senses a wide range of bacteria and viruses or their products and is involved in innate immune responses. In this report, NOD-2 gene was cloned and characterized from rohu (Labeo rohita) which is highly commercially important fish species in the Indian subcontinent. The full length rohu NOD-2 (rNOD-2) cDNA comprised of 3176 bp with a single open reading frame (ORF) of 2949 bp encoding a polypeptide of 982 amino acids (aa) with an estimated molecular mass of 109.65 kDa. The rNOD-2 comprised two N-terminal CARD domains (at 4-91 aa and 111-200 aa), one NACHT domain (at 271-441 aa) and seven C-terminal leucine rich repeat (LRR) regions. Phylogenetically, rNOD-2 was closely related to grass carp NOD-2 (gcNOD2) and exhibited significant similarity (94.2%) and identity (88.6%) in their amino acids. Ontogeny analysis of rNOD-2 showed its constitutive expression across the developmental stages, and highlighted the embryonic innate defense system in fish. Tissue specific analysis of rNOD-2 by quantitative real-time PCR (qRT-PCR) revealed its wide distribution; highest expression was in liver followed by blood. In response to PGN and LTA stimulation, Aeromonas hydrophila and Edwardsiella tarda infection, and poly I:C treatment, expression of rNOD-2 and its associated downstream molecules RICK and IFN-γ were significantly enhanced in the treated fish compared to control. These findings suggested the key role of NOD-2 in augmenting innate immunity in fish in response to bacterial and viral infection. This study may be helpful for the development of preventive measures against infectious diseases in fish.
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Affiliation(s)
- B Swain
- Fish Health Management Division, Central Institute of Freshwater Aquaculture (CIFA), Kausalyaganga, Bhubaneswar, Orissa 751002, India
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Abstract
Initial recognition of bacteria by the innate immune system is thought to occur primarily by germline-encoded pattern recognition receptors (PRRs). These receptors are present in multiple compartments of host cells and are thus capable of surveying both the intracellular and extracellular milieu for bacteria. It has generally been presumed that the cellular location of these receptors dictates what type of bacteria they respond to: extracellular bacteria being recognized by cell surface receptors, such as certain Toll-like receptors, and bacteria that are capable of breaching the plasma membrane and entering the cytoplasm, being sensed by cytoplasmic receptors, including the Nod-like receptors (NLRs). Increasingly, it is becoming apparent that this is a false dichotomy and that extracellular bacteria can be sensed by cytoplasmic PRRs and this is crucial for controlling the levels of these bacteria. In this review, we discuss the role of two NLRs, Nod1 and Nod2, in the recognition of and response to extracellular bacteria.
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Affiliation(s)
- Thomas B Clarke
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6076, USA
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131
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Sorbara MT, Philpott DJ. Peptidoglycan: a critical activator of the mammalian immune system during infection and homeostasis. Immunol Rev 2011; 243:40-60. [PMID: 21884166 DOI: 10.1111/j.1600-065x.2011.01047.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Peptidoglycan is a conserved structural component of the bacterial cell wall with molecular motifs unique to bacteria. The mammalian immune system takes advantage of these properties and has evolved to recognize this microbial associated molecular pattern. Mammals have four secreted peptidoglycan recognition proteins, PGLYRP-1-4, as well as two intracellular sensors of peptidoglycan, Nod1 and Nod2. Recognition of peptidoglycan is important in initiating and shaping the immune response under both homeostatic and infection conditions. During infection, peptidoglycan recognition drives both cell-autonomous and whole-organism defense responses. Here, we examine recent advances in the understanding of how peptidoglycan recognition shapes mammalian immune responses in these diverse contexts.
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Affiliation(s)
- Matthew T Sorbara
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
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132
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White JH. Regulation of intracrine production of 1,25-dihydroxyvitamin D and its role in innate immune defense against infection. Arch Biochem Biophys 2011; 523:58-63. [PMID: 22107948 DOI: 10.1016/j.abb.2011.11.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 11/03/2011] [Indexed: 12/31/2022]
Abstract
Vitamin D was discovered as the cure for nutritional rickets. Classically, hormonal 1,25-dihydroxyvitamin D (1,25D), produced in the kidney by CYP27B1-catalyzed 1α-hydroxylation from its circulating 25-hydroxy precursor, has been considered to function as a critical endocrine regulator of calcium homeostasis. However, our appreciation of vitamin D metabolism and physiological function has evolved dramatically in recent years. First, vitamin D is now recognized as a pleiotropic regulator of human physiology, with emerging roles in cancer chemoprevention, cardio-protection, and, in particular, regulation of immune system functions. Moreover, CYP27B1 is very widely expressed, and evidence is rapidly accumulating that local CYP27B1-catalyzed production of 1,25D, controlled by tissue-specific signals, is critical for its physiological actions. Nowhere is this more apparent than in the innate immune system, where recent studies have shown that CYP27B1 expression is under control of several immune signaling pathways, and that signaling by 1,25D in macrophages and dendritic cells is critical for innate immune responses to infection. This review will describe our current knowledge of the signaling pathways that lead to 1,25D production in the immune system and the downstream signaling events it controls in response to pathogen recognition.
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Affiliation(s)
- John H White
- Department of Physiology, McIntyre Bldg., Rm. 1112, 3655 Drummond St., Montreal, Qc, Canada H3G 1Y6.
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133
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Jensen SR, Nielsen OH, Brix S. Are NOD2 polymorphisms linked to a specific disease endophenotype of Crohn's disease? Inflamm Bowel Dis 2011; 17:2392-401. [PMID: 21337670 DOI: 10.1002/ibd.21656] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 12/31/2010] [Indexed: 12/28/2022]
Abstract
The complex and yet unknown etiology of Crohn's disease (CD) might consist of various disease endophenotypes, each of which represent their own pathogenesis. This review focuses on the disease endophenotype linked to polymorphisms in the nucleotide-binding oligomerization domain containing 2 (NOD2) protein and on the importance of established adherent-invasive E. coli (AIEC) in ileal mucosa. To date, there are several reports pointing to the implications of NOD2 polymorphisms in epithelial and immunological responses against microbes, but the pathological significance of NOD2 mutations in CD is not yet clarified. The enhanced number of pathogenic E. coli in the ileal mucosa of CD as compared to healthy controls may result from a genetically based failure in one of the intestinal bacteria sensing systems, like NOD2, making the ileal epithelium more prone to colonization with microbes harboring specific properties such as AIEC. Increasing the focus on defining subgroups of patients with similar disease initiations, mechanisms of action, and manifestations in CD may be pivotal for the development and implementation of future individualized treatment strategies of benefit for the single patient at an early stage.
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Affiliation(s)
- Stina Rikke Jensen
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Kgs. Lyngby, Denmark.
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Foster N, Berndt A, Lalmanach AC, Methner U, Pasquali P, Rychlik I, Velge P, Zhou X, Barrow P. Emergency and therapeutic vaccination--is stimulating innate immunity an option? Res Vet Sci 2011; 93:7-12. [PMID: 22015261 DOI: 10.1016/j.rvsc.2011.05.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 05/08/2011] [Accepted: 05/24/2011] [Indexed: 01/22/2023]
Abstract
There is increasing evidence that activation of innate immunity, in animals and man, by live vaccines, sub-unit vaccines or synthetic or non-synthetic stimulants can induce a profound and rapidly induced resistance to pathogens, including infectious agents that are unrelated to the stimulating antigen or agent. We review the evidence for this phenomenon and present the proposition that this approach might be used to stimulate immunity during the life of the animal when susceptibility to infection is high and when normal vaccination procedures may be inappropriate.
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Affiliation(s)
- N Foster
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, Loughborough, Leicestershire LE12 5RD, UK
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135
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NOD-like receptors and the innate immune system: Coping with danger, damage and death. Cytokine Growth Factor Rev 2011; 22:257-76. [DOI: 10.1016/j.cytogfr.2011.09.003] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 09/07/2011] [Indexed: 12/26/2022]
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Nimmo ER, Stevens C, Phillips AM, Smith A, Drummond HE, Noble CL, Quail M, Davies G, Aldhous MC, Wilson DC, Satsangi J. TLE1 modifies the effects of NOD2 in the pathogenesis of Crohn's disease. Gastroenterology 2011; 141:972-981.e1-2. [PMID: 21699783 DOI: 10.1053/j.gastro.2011.05.043] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 05/16/2011] [Accepted: 05/20/2011] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS The mechanisms by which specific mutations in NOD2/CARD15 increase the risk for Crohn's disease (CD) are unclear. We identified proteins that interact with NOD2 and investigated them by expression, genetic, and functional analyses. METHODS By using a yeast 2-hybrid screen of an intestinal epithelial library, we identified proteins that interact with NOD2 and confirmed the interactions in mammalian cells using co-immunoprecipitation. We used microarray analysis to analyze gene expression patterns in 302 intestinal biopsy samples (129 from patients with ulcerative colitis [UC], 106 with CD, and 67 controls). Eighty single-nucleotide polymorphisms within the genes that encoded 6 interacting proteins were genotyped in a discovery cohort (869 cases of inflammatory bowel disease [IBD], 885 controls) and a replication cohort (504 patients with IBD, 713 controls). We investigated interaction between transducin-like enhancer of split 1 (TLE1) and NOD2 in HEK293 cells. RESULTS We identified 6 NOD2-interacting proteins (TLE1, UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 2 [GALNT2], HIV-1 Tat interactive protein [HTATIP], Vimentin, fission 1 (mitochondrial outer membrane) homolog [FIS1], and protein phosphatase 2, regulatory subunit B', epsilon isoform [PPP2R5E]). Of these, expression of GALNT2 (CD, P = .004) and vimentin (CD, P = .006; UC, P = .0025) was altered in patients with IBD compared with controls. Single-nucleotide polymorphisms within TLE1 were associated with susceptibility to CD, specifically with ileal disease (rs6559629, P = 3.1 × 10⁻⁵; odds ratio, 1.45). The TLE1 risk allele is required for susceptibility to CD in carriers of NOD2 mutations. In cells, TLE1 and NOD2 co-localized around the nuclear membrane and TLE1 inhibited activation of nuclear factor-κB by NOD2. CONCLUSIONS Epistatic and biological interactions between TLE1 and NOD2 are involved in IBD pathogenesis. NOD2 might be involved in a series of pathways such as epigenetic regulation of expression (via TLE1 and HTATIP), biosynthesis of mucin (via GALNT2), apoptosis (via PPP2R5E and FIS1), and integrity of the intracellular cytoskeleton (vimentin).
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Affiliation(s)
- Elaine R Nimmo
- Gastrointestinal Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Molecular Medicine Centre, Western General Hospital, Edinburgh, UK.
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Biswas A, Petnicki-Ocwieja T, Kobayashi KS. Nod2: a key regulator linking microbiota to intestinal mucosal immunity. J Mol Med (Berl) 2011; 90:15-24. [PMID: 21861185 DOI: 10.1007/s00109-011-0802-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 07/27/2011] [Accepted: 08/09/2011] [Indexed: 12/19/2022]
Abstract
The human intestine harbors a large number of bacteria that are constantly interacting with the intestinal immune system, eliciting non-pathological basal level immune responses. Increasing evidence points to dysbiosis of microbiota in the intestine as an underlying factor in inflammatory bowel disease susceptibility. Loss-of-function mutations in NOD2 are among the stronger genetic factors linked to ileal Crohn's disease. Indeed, Nod2 is a key regulator of microbiota in the intestine, as microflora in the terminal ileum is dysregulated in Nod2-deficient mice. Nod2 is highly expressed in Paneth cells, which are responsible for the regulation of ileal microflora by anti-microbial compounds, and Nod2-deficient ileal intestinal epithelia are unable to kill bacteria efficiently. It is therefore likely that NOD2 mutations in Crohn's disease may increase disease susceptibility by altering interactions between ileal microbiota and mucosal immunity.
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Affiliation(s)
- Amlan Biswas
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Dana 1420A, 450 Brookline Avenue, Boston, MA 02215, USA
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138
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Gutiérrez A, Holler E, Zapater P, Sempere L, Jover R, Pérez-Mateo M, Schoelmerich J, Such J, Wiest R, Francés R. Antimicrobial peptide response to blood translocation of bacterial DNA in Crohn's disease is affected by NOD2/CARD15 genotype. Inflamm Bowel Dis 2011; 17:1641-50. [PMID: 21744420 DOI: 10.1002/ibd.21537] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 09/24/2010] [Indexed: 12/16/2022]
Abstract
BACKGROUND Blood translocation of bacterial-DNA has been described in patients with Crohn's disease (CD). The host's immune cell types cooperate to respond against bacterial insults. Some antimicrobial peptides are inducible after culture with bacterial products and a linkage has been established between them and NOD2/CARD15. The aim was to test whether defensins and cathelicidin (LL-37) expression and NOD2/CARD15 mutations in blood neutrophils are related to molecular bacterial translocation events in CD patients. METHODS Fifty consecutively admitted CD patients and 15 healthy controls were included. Clinical and analytical characteristics of patients were considered. NOD2/CARD15 genotyping, presence of bacterial-DNA, defensin and cathelicidin gene, and protein levels in neutrophils and serum cytokine levels were studied. RESULTS Twenty patients (40%) presented bacterial-DNA in blood. Eleven were active and 9 were in remission. Bacterial-DNA was not present in controls. NOD2/CARD15 mutations were identified in 25 patients (50%), 15 of which were in remission. Sixty percent of bacterial-DNA(+) and 43% of bacterial-DNA(-) patients showed a NOD2/CARD15 mutation. β-Defensin 2 and LL-37 mRNA and protein levels were upregulated in bacterial-DNA(+) patients. β-Defensin 2 and LL-37 expression correlated with bacterial-DNA concentration only in patients with a wildtype NOD2/CARD15 genotype. Cultured neutrophils of bacterial-DNA(-) patients confirmed the muramyl dipeptide-independent association between DEFB2 and LL-37 with bacterial-DNA concentration in wildtype NOD2/CARD15 patients. Cytokine levels were increased in bacterial-DNA(+) patients and correlated with bacterial-DNA concentration. NOD2/CARD15 genotype did not influence this correlation. CONCLUSIONS β-Defensin 2, LL-37, and proinflammatory cytokines are increased in CD patients with bacterial-DNA in a concentration-dependent manner. NOD2/CARD15 plays a key role in the regulation of this response.
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Affiliation(s)
- Ana Gutiérrez
- Servicio de Medicina Digestiva, Hospital General Universitario de Alicante, Alicante, Spain
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139
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Abstract
Ulcerative colitis (UC) is a chronic intestinal inflammatory disease whose etiology is still unknown. It is widely believed that UC is a kind of non-specific inflammatory disease which is caused by environmental factors and autoimmune disorders in people who carry susceptibility genes. Epidemiologic data, such as familial aggregation, twin studies, and racial/ethnic differences in disease prevalence, indicate that there are genetic contributions to UC pathogenesis. In this article, we will review the recent progress in research of genes associated with susceptibility to UC.
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140
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Lee BJ, Bak YT. Irritable bowel syndrome, gut microbiota and probiotics. J Neurogastroenterol Motil 2011; 17:252-66. [PMID: 21860817 PMCID: PMC3155061 DOI: 10.5056/jnm.2011.17.3.252] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 06/09/2011] [Accepted: 06/11/2011] [Indexed: 12/13/2022] Open
Abstract
Irritable bowel syndrome (IBS) is a complex disorder characterized by abdominal symptoms including chronic abdominal pain or discomfort and altered bowel habits. The etiology of IBS is multifactorial, as abnormal gut motility, visceral hypersensitivity, disturbed neural function of the brain-gut axis and an abnormal autonomic nervous system are all implicated in disease progression. Based on recent experimental and clinical studies, it has been suggested that additional etiological factors including low-grade inflammation, altered gut microbiota and alteration in the gut immune system play important roles in the pathogenesis of IBS. Therefore, therapeutic restoration of altered intestinal microbiota may be an ideal treatment for IBS. Probiotics are live organisms that are believed to cause no harm and result in health benefits for the host. Clinical efficacy of probiotics has been shown in the treatment or prevention of some gastrointestinal inflammation-associated disorders including traveler's diarrhea, antibiotics-associated diarrhea, pouchitis of the restorative ileal pouch and necrotizing enterocolitis. The molecular mechanisms, as cause of IBS pathogenesis, affected by altered gut microbiota and gut inflammation-immunity are reviewed. The effect of probiotics on the gut inflammation-immune systems and the results from clinical trials of probiotics for the treatment of IBS are also summarized.
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Affiliation(s)
- Beom Jae Lee
- Department of Gastroenterology, Korea University Guro Hospital, Seoul, Korea
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141
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Kutikhin AG. Role of NOD1/CARD4 and NOD2/CARD15 gene polymorphisms in cancer etiology. Hum Immunol 2011; 72:955-68. [PMID: 21745515 DOI: 10.1016/j.humimm.2011.06.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2011] [Revised: 05/30/2011] [Accepted: 06/08/2011] [Indexed: 02/08/2023]
Abstract
NOD1/CARD4 and NOD2/CARD15 are members of Nod-like receptor family. They are located in cytosol, bind bacterial and viral ligands and play a key role in realization of innate and adaptive immune response, apoptosis, autophagy, and reactive oxygen species generation. Polymorphisms in NOD1/CARD4 and NOD2/CARD15 genes may shift balance between pro- and anti-inflammatory cytokines, modulating the risk of infection, chronic inflammation and cancer. NOD1/CARD4 and NOD2/CARD15 gene polymorphisms may be associated with altered risk of gastric, colorectal, breast, ovarian, prostate, testicular, lung, laryngeal, liver, gallbladder, biliary tract, pancreatic, small bowel, kidney, urinary bladder cancer, skin cancer, nonthyroid endocrine tumors, lymphoma and leukemia. The short list of such polymorphisms perspective for oncogenomic investigations may include rs2006847, rs2066845, rs2066844, rs2066842, ND(1)+32656, rs2075820 whereas rs104895493, rs104895476, rs104895475, rs104895474, rs104895473, rs104895472, rs104895462, rs104895461, rs104895460, rs104895438, rs5743291, rs5743260, rs2076756, rs2066843, Pro371Thr, Ala794Pro, Gln908His, rs72551113, rs72551107, rs6958571, rs2907749, rs2907748, rs2075822, rs2075819, rs2075818 may be added to the extended list. Reasons of discrepancies between different studies include confounding host genetic, bacterial, or environmental factors modulating penetrance of variant allele and affecting risk of condition increasing cancer risk, different bacterial impact in aetiology of such conditions, differences in sample size, clinicopathological characteristics, diagnostics, stratification, genotyping methods, and chance.
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Affiliation(s)
- Anton G Kutikhin
- Department of Epidemiology, Kemerovo State Medical Academy, Kemerovo, Russia.
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142
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Ghadimi D, Hassan M, Njeru PN, de Vrese M, Geis A, Shalabi SI, Abdel-Razek ST, Abdel-Khair AEAA, Heller KJ, Schrezenmeir J. Suppression subtractive hybridization identifies bacterial genomic regions that are possibly involved in hBD-2 regulation by enterocytes. Mol Nutr Food Res 2011; 55:1533-42. [PMID: 21710560 DOI: 10.1002/mnfr.201100052] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Revised: 03/29/2011] [Accepted: 04/15/2011] [Indexed: 02/05/2023]
Abstract
SCOPE Human β-defensin 2 (hBD-2) is an inducible antimicrobial peptide synthesized by the epithelium to counteract bacterial adherence and invasion. It has been suggested that probiotic bacteria sustain gut barrier function via induction of defensins. The goals of this study were (i) to evaluate the potential immunomodulatory effects of 11 different Lactobacillus fermentum strains isolated from Kimere, an African fermented pearl millet (Pennisetum glaucum) dough, on the hBD-2 secretion by human intestinal CaCo-2 cell line and (ii) to examine genetic differences between two strains of L. fermentum (K2-Lb4 and K11-Lb3) which differed in their effect on the production of hBD-2 in this study. METHODS AND RESULTS Totally, 46 strains of L. fermentum from Kimere were isolated and characterized using molecular biology methods including pulsed-field gel electrophoresis patterns. After performing time- and dose-experiments, CaCo-2 cells were incubated with or without bacteria for 12 h. L. fermentum PZ1162 was included as the positive control. Cell-free supernatants were analyzed for hBD-2 protein by enzyme-linked immunosorbent assay (ELISA). To identify potential bacterial genes associated with hBD-2 regulation, suppression subtractive hybridization (SSH) was used. Among the 11 strains tested, only two strains of bacteria, K11-Lb3 and K2-Lb6, significantly induced the production of hBD-2 by CaCo-2 cells. This effect was strain-specific, dose-dependent and particularly seems to be bacterial genomic-dependent as manifested by SSH. L. fermentum strains with and without hBD-2 inducing effect differed in genes encoding proteins involved in glycosylation of cell-wall proteins e.g. glycosyltransferase, UDP-N-acetylglucosamine 2-epimerase, rod shape-determining protein MreC, lipoprotein precursors, sugar ABC transporters, and glutamine ABC transporter ATP-binding protein. CONCLUSION This study implies that certain strains of L. fermentum isolated from Kimere may stimulate the intestinal innate defense through the induction of hBD-2. The molecular basis of hBD-2 induction by L. fermentum strain K11-Lb3 may be based on glycosylated cell-surface structures synthesized with the aid of glycosyltransferase, UDP-N-acetylglucosamine 2-epimerase, and rod shape-determining protein MreC.
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Affiliation(s)
- Darab Ghadimi
- Department of Physiology and Biochemistry of Nutrition, Max Rubner-Institut, Hermann-Weigmann, Kiel, Germany.
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143
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Beisner J, Stange EF, Wehkamp J. Innate antimicrobial immunity in inflammatory bowel diseases. Expert Rev Clin Immunol 2011; 6:809-18. [PMID: 20828289 DOI: 10.1586/eci.10.56] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inflammatory bowel diseases are characterized by chronic intestinal inflammation at different sites. Data from animal models as well as human patients including gene-association studies suggest that different components of the innate barrier function are primarily defective. These recent advances support the evolving hypothesis that intestinal bacteria induce inflammation predominantly as a result of a weakened innate mucosal barrier in genetically predisposed individuals. This article discusses our current understanding of the primary events of disease. Together, these findings should result in new therapeutic avenues aimed at restoring antimicrobial barrier function to prevent a bacterial-triggered inflammatory response.
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Affiliation(s)
- Julia Beisner
- Dr Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Germany
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144
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The role of innate immunity in donor organ procurement. Semin Immunopathol 2011; 33:169-84. [DOI: 10.1007/s00281-011-0254-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Accepted: 01/13/2011] [Indexed: 12/18/2022]
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145
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Petnicki-Ocwieja T, DeFrancesco AS, Chung E, Darcy CT, Bronson RT, Kobayashi KS, Hu LT. Nod2 suppresses Borrelia burgdorferi mediated murine Lyme arthritis and carditis through the induction of tolerance. PLoS One 2011; 6:e17414. [PMID: 21387014 PMCID: PMC3046161 DOI: 10.1371/journal.pone.0017414] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 01/31/2011] [Indexed: 01/07/2023] Open
Abstract
The internalization of Borrelia burgdorferi, the causative agent of Lyme disease, by phagocytes is essential for an effective activation of the immune response to this pathogen. The intracellular, cytosolic receptor Nod2 has been shown to play varying roles in either enhancing or attenuating inflammation in response to different infectious agents. We examined the role of Nod2 in responses to B. burgdorferi. In vitro stimulation of Nod2 deficient bone marrow derived macrophages (BMDM) resulted in decreased induction of multiple cytokines, interferons and interferon regulated genes compared with wild-type cells. However, B. burgdorferi infection of Nod2 deficient mice resulted in increased rather than decreased arthritis and carditis compared to control mice. We explored multiple potential mechanisms for the paradoxical response in in vivo versus in vitro systems and found that prolonged stimulation with a Nod2 ligand, muramyl dipeptide (MDP), resulted in tolerance to stimulation by B. burgdorferi. This tolerance was lost with stimulation of Nod2 deficient cells that cannot respond to MDP. Cytokine patterns in the tolerance model closely paralleled cytokine profiles in infected Nod2 deficient mice. We propose a model where Nod2 has an enhancing role in activating inflammation in early infection, but moderates inflammation after prolonged exposure to the organism through induction of tolerance.
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Affiliation(s)
- Tanja Petnicki-Ocwieja
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, Massachusetts, United States of America
| | - Alicia S. DeFrancesco
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, Massachusetts, United States of America
| | - Erin Chung
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, Massachusetts, United States of America
| | - Courtney T. Darcy
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, Massachusetts, United States of America
| | - Roderick T. Bronson
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Koichi S. Kobayashi
- Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Linden T. Hu
- Division of Geographic Medicine and Infectious Diseases, Tufts Medical Center, Boston, Massachusetts, United States of America
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146
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Billmann-Born S, Lipinski S, Böck J, Till A, Rosenstiel P, Schreiber S. The complex interplay of NOD-like receptors and the autophagy machinery in the pathophysiology of Crohn disease. Eur J Cell Biol 2010; 90:593-602. [PMID: 21146253 DOI: 10.1016/j.ejcb.2010.10.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 10/20/2010] [Accepted: 10/22/2010] [Indexed: 02/07/2023] Open
Abstract
Several coding variants of NOD2 and ATG16L1 are associated with increased risk of Crohn disease (CD). NOD2, a cytosolic receptor of the innate immune system activates pro-inflammatory signalling cascades upon recognition of bacterial muramyl dipeptide, but seems also to be involved in antiviral and anti-parasitic defence programs. The CD associated variant L1007fsinsC leads to impaired pro-inflammatory signalling and diminished bacterial clearance. ATG16L1 is a protein essential for autophagosome formation at the phagophore assembly site. The CD associated T300A variant is located in the c-terminal WD40 domain, whose function is still unknown. Basal autophagy is not affected by the T300A variant, but antibacterial autophagy (xenophagy) is impaired, a finding that relates ATG16L1 as well as NOD2 to pathogen defence. Notably, combination of disease-associated alleles of ATG16L1 and NOD2/CARD15 leads to synergistically increased susceptibility for CD, indicating a possible crosstalk between NOD2- and ATG16L1-mediated processes in the pathogenesis of CD. This review surveys current research results and discusses the functional models of potential interplay between NLR-pathways and xenophagy. Interaction between pathways is discussed in the context of reactive oxygen species (ROS), membrane co-localisation, antigen processing and implications of disturbed Paneth cell vesicle export. These effects on pathogen response might imbalance the intestinal barrier epithelia towards chronic inflammation and promote development of Crohn disease. Further elucidation of NOD2/ATG16L1 interplay in xenophagy is relevant for understanding the aetiology of chronic intestinal inflammation and host-microbe interaction in general and could lead to principal new insights to xenophagy induction.
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Affiliation(s)
- Susanne Billmann-Born
- Institute of Clinical Molecular Biology, Christian-Albrechts-University, Kiel, Germany
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147
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Klapproth JMA, Sasaki M. Bacterial induction of proinflammatory cytokines in inflammatory bowel disease. Inflamm Bowel Dis 2010; 16:2173-9. [PMID: 20848533 DOI: 10.1002/ibd.21332] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
It has become increasingly clear that inflammatory bowel disease (IBD) develops on the background of genetic defects in the host, conveying an increased susceptibility to an environmental antigen or antigens. The environmental factor implicated in the pathophysiology of gut inflammation, which is undergoing increased scrutiny, is the intestinal flora. The intestinal flora as a whole and specific bacteria and their products have been found to trigger cytokine expression in various cell types. Consistently, multiple bacterial strains were found to induce tumor necrosis factor alpha (TNF-α) and interleukin-8 (IL-8) in macrophage and epithelial cell systems, respectively, in particular in Crohn's disease. Interestingly, various cell types from patients with IBD display an increased susceptibility to specific bacterial products, including flagellin, pili, and lipopolysaccharides. It remains to be determined whether additional effector proteins regulate cytokine expression and the aberrant mucosal immune response in IBD.
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148
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Jäger S, Stange EF, Wehkamp J. Antimicrobial peptides in gastrointestinal inflammation. Int J Inflam 2010; 2010:910283. [PMID: 21151692 PMCID: PMC2992817 DOI: 10.4061/2010/910283] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 08/18/2010] [Indexed: 12/19/2022] Open
Abstract
Acute and chronic inflammations of mucosal surfaces are complex events in which the effector mechanisms of innate and adaptive immune systems interact with pathogenic and commensal bacteria. The role of constitutive and inducible antimicrobial peptides in intestinal inflammation has been investigated thoroughly over the recent years, and their involvement in various disease states is expanded ever more. Especially in the intestines, a critical balance between luminal bacteria and the antimicrobial peptides is essential, and a breakdown in barrier function by impaired production of defensins is already implicated in Crohn's disease. In this paper, we focus on the role of antimicrobial peptides in inflammatory processes along the gastrointestinal tract, while considering the resident and pathogenic flora encountered at the specific sites. The role of antimicrobial peptides in the primary events of inflammatory bowel diseases receives special attention.
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Affiliation(s)
- Simon Jäger
- Department of Internal Medicine I, Robert Bosch Hospital, Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Auerbachstr. 112, 70376 Stuttgart, Germany
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149
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Marinis JM, Homer CR, McDonald C, Abbott DW. A novel motif in the Crohn's disease susceptibility protein, NOD2, allows TRAF4 to down-regulate innate immune responses. J Biol Chem 2010; 286:1938-50. [PMID: 21097508 DOI: 10.1074/jbc.m110.189308] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The Crohn's disease and early onset sarcoidosis susceptibility protein, NOD2, coordinates innate immune signaling pathways. Because dysregulation of this coordination can lead to inflammatory disease, maintaining appropriate activation of the NOD2 signaling pathway is paramount in immunologic homeostasis. In this work, we identify the atypical tumor necrosis factor-associated factor (TRAF) family member, TRAF4, as a key negative regulator of NOD2 signaling. TRAF4 inhibits NOD2-induced NF-κB activation and directly binds to NOD2 to inhibit NOD2-induced bacterial killing. We find that two consecutive glutamate residues in NOD2 are required for interaction with TRAF4 and inhibition of NOD2 signaling because mutation of these residues abrogated both TRAF4 binding and inhibition of NOD2. This work identifies a novel negative regulator of NOD2 signaling. Additionally, it defines a TRAF4 binding motif within NOD2 involved in termination of innate immune signaling responses.
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Affiliation(s)
- Jill M Marinis
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
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150
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Skin commensals amplify the innate immune response to pathogens by activation of distinct signaling pathways. J Invest Dermatol 2010; 131:382-90. [PMID: 21048787 DOI: 10.1038/jid.2010.328] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Little is known about the impact of different microbial signals on skin barrier organ function and the interdependency between resident microflora and pathogenic microorganisms. This study shows that commensal and pathogenic staphylococci differ in their ability to induce expression of antimicrobial peptides/proteins (AMPs) and activate different signaling pathways in human primary keratinocytes. Whereas secreted factors of skin commensals induce expression of the AMPs HBD-3 and RNase7 in primary human keratinocytes via Toll-like receptor (TLR)-2, EGFR, and NF-κB activation, those of pathogenic staphylococci activate the mitogen-activated protein kinase and phosphatidylinositol 3-kinase/AKT signaling pathways and suppress NF-κB activation. Interestingly, commensal bacteria are able to amplify the innate immune response of human keratinocytes to pathogens by increased induction of AMP expression and abrogation of NF-κB suppression, suggesting that the two activation pathways can act in a synergistic way. These data indicate that commensal and pathogenic microorganisms evolved specific mechanisms to modulate innate immunity of the skin.
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