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Bai L, Zhou Y, Sheng C, Yin Y, Chen Y, Ding X, Yu G, Yang G, Chen L. Common carp Peptidoglycan Recognition Protein 2 (CcPGRP2) plays a role in innate immunity for defense against bacterial infections. FISH & SHELLFISH IMMUNOLOGY 2023; 133:108564. [PMID: 36690267 DOI: 10.1016/j.fsi.2023.108564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 01/04/2023] [Accepted: 01/20/2023] [Indexed: 06/17/2023]
Abstract
PGRP is a family of pattern recognition molecules of the innate immune system. PGRPs are conserved from insects to mammals and have diverse functions in antimicrobial defense. Here we cloned a common carp PGRP ortholog, CcPGRP2 containing a conserved C-terminal PGRP domain. We tested the expression levels of CcPGRP2 in the liver, spleen, kidney, foregut, midgut, and hindgut of the highest level in the liver. The expression of CcPGRP2 upregulated in common carp infected with Aeromonas hydrophila (A. hydrophila) or Staphylococcus aureus (S. aureus). Recombinant CcPGRP2 protein expressed in Escherichia coli (E. coli) system and the purified CcPGRP2 could maintain the integrity of intestinal mucosa of common carp infected with A. hydrophila. In addition, CcPGRP2 could agglutinate or bind both gram-positive and gram-negative bacteria in a Zn2+-dependent manner. CcPGRP2 has a stronger agglutination and bacterial binding ability in gram-positive bacteria than in gram-negative bacteria. It is perhaps because CcPGRP2 could bind peptidoglycan (PGN) with a higher degree to lipopolysaccharide (LPS). And CcPGRP2 shows antimicrobial activities in the presence of Zn2+. Our results of CcPGRP2 provided new insight into the function of PGRP in the innate immunity of the common carp.
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Affiliation(s)
- Linyi Bai
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250000, PR China
| | - Yuan Zhou
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250000, PR China
| | - Chen Sheng
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250000, PR China
| | - Yizhi Yin
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250000, PR China
| | - Yanru Chen
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250000, PR China
| | - Xinli Ding
- Department of Food Industry, Shandong Institute of Commerce and Technology, No.4516 Lvyou Road, Jinan, 250103, PR China
| | - Guanliu Yu
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250000, PR China
| | - Guiwen Yang
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250000, PR China
| | - Lei Chen
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250000, PR China.
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Conjunctival epitheliopathy induced by topical exposure to bacterial peptidoglycan, muramyl dipeptide. Exp Eye Res 2023; 227:109383. [PMID: 36634837 DOI: 10.1016/j.exer.2023.109383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 11/02/2022] [Accepted: 01/05/2023] [Indexed: 01/11/2023]
Abstract
Noninfectious exudative conjunctivitis can be experimentally produced in rabbits by application of the apoptogenic bacterial cell wall peptidoglycan, muramyl dipeptide (MDP) to the ocular surface. The purpose of this study was to investigate the acute conjunctival cytopathology induced by unilateral ocular surface exposure to MDP. Hematoxylin and eosin staining assessed bilateral tear cytopathology and conjunctival histopathology. The caspases levels in conjunctival tissue and tears were measured in standard assays utilizing p-nitroanaline tagged caspase-specific substrates. Immunofluorescent antibody identified intracellular caspase-3, nuclear factor-κβ (NF-κβ), and oxidative DNA damage (8-OHdG; 8-oxo-2'-deoxyguanosine) in tear and conjunctiva cells. DNA extracted from conjunctival tissues and pooled tear fluids were visualized by ethydium bromide agarose gel electrophoresis. Onset of ipsilateral conjunctivitis was due to an epitheliopathy characterized by loss of conjunctival epithelial cell adherence, exuviation of conjunctival epithelial cells, and neutrophil infiltration. Caspase-3 levels were significantly higher in exuviated cells in ipsilateral than contralateral tear (p's ≤ 0.001) collected at 3-5 h post MDP. Significantly higher caspase-2, -3, -6, -8 and -9 (p's ≤ 0.03) levels were detected in ipsilateral than contralateral conjunctival tissue at 5 h. Polymeric DNA was detected in ipsilateral but not contralateral conjunctival tissue and tears. Caspase-3, NF-κβ, and 8-OHdG positive neutrophils were detected in bilateral conjunctiva and tear. The caspase-3/NF-κβ epithelial cells and polymeric DNA in conjunctival tissue and shedding of caspase positive cells and polymeric DNA into ipsilateral tears support MDP induction of acute programmed cell death in vivo. The results suggest that ipsilateral exudative conjunctivitis is due to acute caspase-mediated conjunctival epitheliopathy induced by topical exposure to the bacterial peptidoglycan MDP.
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Iqbal Z, Fachim HA, Gibson JM, Baricevic-Jones I, Campbell AE, Geary B, Donn RP, Hamarashid D, Syed A, Whetton AD, Soran H, Heald AH. Changes in the Proteome Profile of People Achieving Remission of Type 2 Diabetes after Bariatric Surgery. J Clin Med 2021; 10:3659. [PMID: 34441954 PMCID: PMC8396849 DOI: 10.3390/jcm10163659] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/17/2021] [Accepted: 08/17/2021] [Indexed: 02/07/2023] Open
Abstract
Bariatric surgery (BS) results in metabolic pathway recalibration. We have identified potential biomarkers in plasma of people achieving type 2 diabetes mellitus (T2DM) remission after BS. Longitudinal analysis was performed on plasma from 10 individuals following Roux-en-Y gastric bypass (n = 7) or sleeve gastrectomy (n = 3). Sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS) was done on samples taken at 4 months before (baseline) and 6 and 12 months after BS. Four hundred sixty-seven proteins were quantified by SWATH-MS. Principal component analysis resolved samples from distinct time points after selection of key discriminatory proteins: 25 proteins were differentially expressed between baseline and 6 months post-surgery; 39 proteins between baseline and 12 months. Eight proteins (SHBG, TF, PRG4, APOA4, LRG1, HSPA4, EPHX2 and PGLYRP) were significantly different to baseline at both 6 and 12 months post-surgery. The panel of proteins identified as consistently different included peptides related to insulin sensitivity (SHBG increase), systemic inflammation (TF and HSPA4-both decreased) and lipid metabolism (APOA4 decreased). We found significant changes in the proteome for eight proteins at 6- and 12-months post-BS, and several of these are key components in metabolic and inflammatory pathways. These may represent potential biomarkers of remission of T2DM.
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Affiliation(s)
- Zohaib Iqbal
- The School of Medicine and Manchester Academic Health Sciences Centre, Manchester University, Manchester M13 9PL, UK; (Z.I.); (J.M.G.); (R.P.D.); (H.S.)
- Department of Endocrinology, Diabetes and Metabolism, Salford Royal Foundation Trust, Salford M6 8HD, UK; (D.H.); (A.S.)
| | - Helene A. Fachim
- The School of Medicine and Manchester Academic Health Sciences Centre, Manchester University, Manchester M13 9PL, UK; (Z.I.); (J.M.G.); (R.P.D.); (H.S.)
- Department of Endocrinology, Diabetes and Metabolism, Salford Royal Foundation Trust, Salford M6 8HD, UK; (D.H.); (A.S.)
| | - J. Martin Gibson
- The School of Medicine and Manchester Academic Health Sciences Centre, Manchester University, Manchester M13 9PL, UK; (Z.I.); (J.M.G.); (R.P.D.); (H.S.)
- Department of Endocrinology, Diabetes and Metabolism, Salford Royal Foundation Trust, Salford M6 8HD, UK; (D.H.); (A.S.)
| | - Ivona Baricevic-Jones
- Stoller Biomarker Discovery Centre, Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (I.B.-J.); (A.E.C.); (B.G.); (A.D.W.)
| | - Amy E. Campbell
- Stoller Biomarker Discovery Centre, Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (I.B.-J.); (A.E.C.); (B.G.); (A.D.W.)
| | - Bethany Geary
- Stoller Biomarker Discovery Centre, Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (I.B.-J.); (A.E.C.); (B.G.); (A.D.W.)
| | - Rachelle P. Donn
- The School of Medicine and Manchester Academic Health Sciences Centre, Manchester University, Manchester M13 9PL, UK; (Z.I.); (J.M.G.); (R.P.D.); (H.S.)
| | - Dashne Hamarashid
- Department of Endocrinology, Diabetes and Metabolism, Salford Royal Foundation Trust, Salford M6 8HD, UK; (D.H.); (A.S.)
| | - Akheel Syed
- Department of Endocrinology, Diabetes and Metabolism, Salford Royal Foundation Trust, Salford M6 8HD, UK; (D.H.); (A.S.)
| | - Anthony D. Whetton
- Stoller Biomarker Discovery Centre, Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK; (I.B.-J.); (A.E.C.); (B.G.); (A.D.W.)
- Manchester National Institute for Health Research Biomedical Research Centre, Manchester M13 9WL, UK
| | - Handrean Soran
- The School of Medicine and Manchester Academic Health Sciences Centre, Manchester University, Manchester M13 9PL, UK; (Z.I.); (J.M.G.); (R.P.D.); (H.S.)
| | - Adrian H. Heald
- The School of Medicine and Manchester Academic Health Sciences Centre, Manchester University, Manchester M13 9PL, UK; (Z.I.); (J.M.G.); (R.P.D.); (H.S.)
- Department of Endocrinology, Diabetes and Metabolism, Salford Royal Foundation Trust, Salford M6 8HD, UK; (D.H.); (A.S.)
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Ho CH, Cheng CH, Huang TW, Peng SY, Lee KM, Cheng PC. Switched phenotypes of macrophages during the different stages of Schistosoma japonicum infection influenced the subsequent trends of immune responses. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2021; 55:503-526. [PMID: 34330662 DOI: 10.1016/j.jmii.2021.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/28/2021] [Accepted: 06/24/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Macrophages play crucial roles in immune responses during the course of schistosomal infections. METHODS We currently investigated influence of immunocompetent changes in macrophages via microarray-based analysis, mRNA expression analysis, detection of serum cytokines, and subsequent evaluation of the immune phenotypes following the differentiation of infection-induced lymphocytes in a unique T1/T2 double-transgenic mouse model. RESULTS The gradual upregulation of genes encoding YM1, YM2, and interleukin (IL)-4/IL-13 receptors in infected mice indicated the role of type 2 alternatively activated macrophages (M2, AAMφs) in immune responses after Schistosoma japonicum egg production. FACS analysis showed that surface markers MHC class II (IA/IE) and CD8α+ of the macrophages also exhibited a dramatic change at the various time points before and after egg-production. The transgenic mouse experiments further demonstrated that the shifting of macrophage phenotypes influenced the percentage of helper T (Th)-2 cells, which was observed to be higher than that of Th1 cells, which increased only at 3 and 5 weeks post-infection. The differentiation of effector B cells showed a similar but more significant trend toward type-2 immunity. CONCLUSION These results suggest that the infection of mice with S. japonicum resulted in a final Th2- and Be2-skewed immune response. This may be due to phenotypic changes in the macrophages. The influence of alternatively activated macrophages was also activated by S. japonicum egg production. This study elucidated the existence of variations in immune mechanisms at the schistosome infection stages.
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Affiliation(s)
- Chen-Hsun Ho
- Division of Urology, Department of Surgery, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan; School of Medicine, College of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Chia-Hsiung Cheng
- Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Tzu-Wen Huang
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Shih-Yi Peng
- Department of Biochemistry, College of Medicine, Tzu Chi University, Hualien, Taiwan.
| | - Kin-Mu Lee
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Po-Ching Cheng
- Department of Molecular Parasitology and Tropical Diseases, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Center for International Tropical Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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Loomis KH, Wu SK, Ernlund A, Zudock K, Reno A, Blount K, Karig DK. A mixed community of skin microbiome representatives influences cutaneous processes more than individual members. MICROBIOME 2021; 9:22. [PMID: 33482907 PMCID: PMC7825201 DOI: 10.1186/s40168-020-00963-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 12/06/2020] [Indexed: 05/06/2023]
Abstract
BACKGROUND Skin, the largest organ of the human body by weight, hosts a diversity of microorganisms that can influence health. The microbial residents of the skin are now appreciated for their roles in host immune interactions, wound healing, colonization resistance, and various skin disorders. Still, much remains to be discovered in terms of the host pathways influenced by skin microorganisms, as well as the higher-level skin properties impacted through these microbe-host interactions. Towards this direction, recent efforts using mouse models point to pronounced changes in the transcriptional profiles of the skin in response to the presence of a microbial community. However, there is a need to quantify the roles of microorganisms at both the individual and community-level in healthy human skin. In this study, we utilize human skin equivalents to study the effects of individual taxa and a microbial community in a precisely controlled context. Through transcriptomics analysis, we identify key genes and pathways influenced by skin microbes, and we also characterize higher-level impacts on skin processes and properties through histological analyses. RESULTS The presence of a microbiome on a 3D skin tissue model led to significantly altered patterns of gene expression, influencing genes involved in the regulation of apoptosis, proliferation, and the extracellular matrix (among others). Moreover, microbiome treatment influenced the thickness of the epidermal layer, reduced the number of actively proliferating cells, and increased filaggrin expression. Many of these findings were evident upon treatment with the mixed community, but either not detected or less pronounced in treatments by single microorganisms, underscoring the impact that a diverse skin microbiome has on the host. CONCLUSIONS This work contributes to the understanding of how microbiome constituents individually and collectively influence human skin processes and properties. The results show that, while it is important to understand the effect of individual microbes on the host, a full community of microbes has unique and pronounced effects on the skin. Thus, in its impacts on the host, the skin microbiome is more than the sum of its parts. Video abstract.
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Affiliation(s)
- Kristin H. Loomis
- Research and Exploratory Development, Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Susan K. Wu
- Research and Exploratory Development, Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Amanda Ernlund
- Research and Exploratory Development, Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Kristina Zudock
- Research and Exploratory Development, Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - Allison Reno
- Department of Bioengineering, Clemson University, Clemson, SC USA
| | - Kianna Blount
- Research and Exploratory Development, Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - David K. Karig
- Research and Exploratory Development, Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
- Department of Bioengineering, Clemson University, Clemson, SC USA
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Yang Z, Feng J, Xiao L, Chen X, Yao Y, Li Y, Tang Y, Zhang S, Lu M, Qian Y, Wu H, Shi M. Tumor-Derived Peptidoglycan Recognition Protein 2 Predicts Survival and Antitumor Immune Responses in Hepatocellular Carcinoma. Hepatology 2020; 71:1626-1642. [PMID: 31479523 PMCID: PMC7318564 DOI: 10.1002/hep.30924] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 08/28/2019] [Indexed: 12/30/2022]
Abstract
BACKGROUND AND AIMS Hepatocellular carcinoma (HCC) is linked to immunosuppression. Relieving immunosuppression has been an attractive strategy to improve the efficacy of cancer immunotherapy. Peptidoglycan recognition protein 2 (PGLYRP2) is a pattern recognition receptor which is specifically expressed in liver and implicated in the regulation of innate immunity and immunosurveillance. However, the role of hepatic PGLYRP2 in modulating immune responses against HCC remains to be investigated. APPROACH AND RESULTS In this study, we investigated whether PGLYRP2 is able to influence HCC progression through regulating host antitumor immune responses. We demonstrated that PGLYRP2 was down-regulated in HCC, which was linked with poor prognosis in patients (P < 0.001). PGLYRP2 overexpression in HCC cells significantly enhanced antitumor immune responses in immune-competent mice and elevated immune response rates of peripheral blood mononuclear cells against HCC. Mechanistically, DNA methyltransferase 3A-mediated promoter hypermethylation was responsible for the down-regulation of PGLYRP2 in HCC. PGLYRP2 promoted production of chemokine (C-C motif) ligand 5 (CCL5) in HCC through binding to the CCL5 promoter, which contributed to the enhanced antitumor immunity. CONCLUSIONS We provide evidence that tumor-derived PGLYRP2 acts as a candidate biomarker for adequate immune response against HCC and improved patient outcomes, indicating the importance of hepatic PGLYRP2 in cancer immunosurveillance and in designing immunotherapeutic approaches.
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Affiliation(s)
- Zongyi Yang
- School of Life Science and TechnologyHarbin Institute of TechnologyHarbinChina
| | - Jia Feng
- School of Life Science and TechnologyHarbin Institute of TechnologyHarbinChina
| | - Li Xiao
- School of Life Science and TechnologyHarbin Institute of TechnologyHarbinChina
| | - Xi Chen
- School of Life Science and TechnologyHarbin Institute of TechnologyHarbinChina
| | - Yuanfei Yao
- Department of Gastrointestinal Medical OncologyThird Affiliated Hospital of Harbin Medical UniversityHarbinChina
| | - Yiqun Li
- School of Life Science and TechnologyHarbin Institute of TechnologyHarbinChina
| | - Yu Tang
- School of Life Science and TechnologyHarbin Institute of TechnologyHarbinChina
| | - Shuai Zhang
- School of Life Science and TechnologyHarbin Institute of TechnologyHarbinChina
| | - Min Lu
- School of Life Science and TechnologyHarbin Institute of TechnologyHarbinChina
| | - Yu Qian
- School of Life Science and TechnologyHarbin Institute of TechnologyHarbinChina
| | - Hongjin Wu
- The NHC Key Laboratory of Drug Addition MedicineFirst Affiliated Hospital of Kunming Medical UniversityKunmingChina
| | - Ming Shi
- School of Life Science and TechnologyHarbin Institute of TechnologyHarbinChina
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Hu Z, Cao X, Guo M, Li C. Identification and characterization of a novel short-type peptidoglycan recognition protein in Apostichopus japonicus. FISH & SHELLFISH IMMUNOLOGY 2020; 99:257-266. [PMID: 32061713 DOI: 10.1016/j.fsi.2020.02.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 06/10/2023]
Abstract
Peptidoglycan recognition proteins (PGRPs) are pattern recognition molecules of the innate immune system via specific recognizing peptidoglycan, a unique component of bacterial cell wall. In the present study, a homologous gene encoding PGRP-S was identified and characterized from Apostichopus japonicus and designated as AjPGRP-S. The open reading frame of AjPGRP-S is 756 bp encoding a polypeptide of 251 amino acids (aa) with a signal peptide (1-24 aa) and a typical PGRP domain (37-178 aa). Phylogenetic analysis and sequence alignment revealed that AjPGRP-S is a member of the PGRP-S family. In healthy sea cucumbers, AjPGRP-S was expressed in all examined tissues with the highest distribution in body wall, muscle, and intestine. In Vibrio splendidus-infected sea cucumbers, AjPGRP-S was remarkably induced in coelomocytes. The recombinant AjPGRP-S (rAjPGRP-S) was shown to possess the highly amidase activity in the presence of Zn2+. Moreover, rAjPGRP-S exhibited agglutination abilities and strong bacteriostatic activities against V. splendidus, V. harveyi, V. parahaemolyticus, Staphylococcus aureus, and Micrococcus luteus. Furthermore, the agglutination ability can be enhanced in the presence of Zn2+. In conclusion, our results suggested that AjPGRP-S serves as a pattern recognition molecule involved in the immune response towards various pathogenic infections.
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Affiliation(s)
- Zhenguo Hu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, PR China
| | - Xuebin Cao
- National Algae and Sea Cucumber Project Technology Research Center, Shandong Oriental Ocean Sci-Tech Company Limited, Yantai, 264003, PR China
| | - Ming Guo
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, PR China
| | - Chenghua Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, PR China.
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Dabrowski AN, Conrad C, Behrendt U, Shrivastav A, Baal N, Wienhold SM, Hackstein H, N'Guessan PD, Aly S, Reppe K, Suttorp N, Zahlten J. Peptidoglycan Recognition Protein 2 Regulates Neutrophil Recruitment Into the Lungs After Streptococcus pneumoniae Infection. Front Microbiol 2019; 10:199. [PMID: 30837960 PMCID: PMC6389715 DOI: 10.3389/fmicb.2019.00199] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 01/24/2019] [Indexed: 12/22/2022] Open
Abstract
Peptidoglycan (PGN) recognition proteins (PGLYRPs) are a highly conserved group of host defense proteins in insects and mammals that sense bacterial cell wall PGN and act bactericidally or cleave PGN by amidase function. Streptococcus (S.) pneumoniae is one of the top five killers worldwide and causes, e.g., pneumonia, endocarditis, meningitis and sepsis. S. pneumoniae accounts for approximately 1.5–2 million deaths every year. The risk of antibiotic resistance and a general poor prognosis in young children and elderly people have led to the need for new treatment approaches. To the best of our knowledge, there is no report on the relevance of PGLYRP2 in lung infections. Therefore, we infected mice deficient for PGLYRP2 transnasally with S. pneumoniae and examined the innate immune response in comparison to WT animals. As expected, PGLYRP2-KO animals had to be sacrificed earlier than their WT counterparts, and this was due to higher bacteremia. The higher bacterial load in the PGLYRP2-KO mice was accomplished with lower amounts of proinflammatory cytokines in the lungs. This led to an abolished recruitment of neutrophils into the lungs, the spread of bacteria and the subsequent aggravated course of the disease and early mortality of the PGLYRP2-KO mice. These data suggest a substantial role of PGLYRP2 in the early defense against S. pneumoniae infection, and PGLYRP2 might also affect other infections in the lungs.
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Affiliation(s)
- Alexander N Dabrowski
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Claudia Conrad
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ulrike Behrendt
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Anshu Shrivastav
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Nelli Baal
- Immunology and Transfusion Medicine, Justus Liebig University Giessen, Giessen, Germany
| | - Sandra M Wienhold
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Division of Pulmonary Inflammation, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Holger Hackstein
- Immunology and Transfusion Medicine, Justus Liebig University Giessen, Giessen, Germany
| | - Philippe D N'Guessan
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Sahar Aly
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Katrin Reppe
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Division of Pulmonary Inflammation, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Norbert Suttorp
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Janine Zahlten
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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Dietary fatty acid source has little effect on the development of the immune system in the pyloric caeca of Atlantic salmon fry. Sci Rep 2019; 9:27. [PMID: 30631091 PMCID: PMC6328623 DOI: 10.1038/s41598-018-37266-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 11/29/2018] [Indexed: 12/26/2022] Open
Abstract
The quality and relative amounts of dietary lipids may affect the health and growth of cultured Atlantic salmon. So far, little is known about their effects on the performance of the fish immune system during early life stages and, in particular their importance in the transition from endogenous nutrition (yolk) in the alevin stage to exogenous nutrition in the later fry stage. We investigated the immunomodulatory effects of fish oil, vegetable oil and phospholipid-rich oil in feeds for farmed Atlantic salmon using a transcriptomic approach. The experiment allowed a fine-scale monitoring of gene expression profiles in two tissues, the pyloric caeca of the intestine and the liver, in a 94 days-long first feeding experiment. The analysis of transcriptional profiles revealed that first feeding induced a strong immunomodulation in the pyloric caeca after 48 days of feeding, lasting up to day 94 and possibly beyond. On the other hand, the differential effect of the three dietary regimes was negligible. We interpret this upregulation, undetectable in liver, as a potentiation of the immune system upon the first contact of the digestive system with exogenous feed. This process involved a complex network of gene products involved in both cellular and humoral immunity. We identified the classical pathway of the complement system, acting at the crossroads between innate and adaptive immunity, as a key process modulated in response to the switch from endogenous to exogenous nutrition.
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Choi KM, Joo MS, Cho DH, Bae JS, Jung JM, Hwang JY, Kwon MG, Seo JS, Hwang SD, Jee BY, Kim DH, Park CI. Characterization of gene expression profiles and functional analysis of peptidoglycan recognition protein 2 from rock bream (Oplegnathus fasciatus). FISH & SHELLFISH IMMUNOLOGY 2019; 84:1068-1074. [PMID: 30439496 DOI: 10.1016/j.fsi.2018.11.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/18/2018] [Accepted: 11/10/2018] [Indexed: 06/09/2023]
Abstract
Peptidoglycan recognition protein 2 (PGRP2) is a Zn2+-dependent peptidase that plays important roles in binding to microbial components of the cell membrane, inducing phagocytosis and antimicrobial activity. Rock bream (Oplegnathus fasciatus) PGRP2 (RbPGRP2) was identified in the intestine by next generation sequencing (NGS) analysis. The open reading frame (ORF) the RbPGRP2 cDNA (470 amino acid residues) contains a peptidoglycan recognition protein domain (residues 300 to 446). Alignment analysis revealed that RbPGRP2 shares 37.6-53.5% overall sequence identity with the PGRP2s of other species. Phylogenetic analysis revealed that RbPGRP2 clustered together with PGRP2s from teleosts. In healthy rock bream, RbPGRP2 was found to be ubiquitously expressed in all of the examined tissues, especially in the liver. RbPGRP2 expression was significantly upregulated in all of the examined tissues of rock bream after infection with Edwardsiella piscicida, Streptococcus iniae and red sea bream iridovirus (RSIV) compared with the control. Purified rRbPGRP2 interactions with bacteria and inhibited the growth of bacteria in the presence of Zn2+. These results indicate that RbPGRP2 plays an important role in the innate immune response against bacterial infection.
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Affiliation(s)
- Kwang-Min Choi
- Institute of Marine Industry, College of Marine Science, Gyeongsang National University, 455, Tongyeong, 650-160, Republic of Korea
| | - Min-Soo Joo
- Institute of Marine Industry, College of Marine Science, Gyeongsang National University, 455, Tongyeong, 650-160, Republic of Korea
| | - Dong Hee Cho
- Institute of Marine Industry, College of Marine Science, Gyeongsang National University, 455, Tongyeong, 650-160, Republic of Korea
| | - Jin-Sol Bae
- Institute of Marine Industry, College of Marine Science, Gyeongsang National University, 455, Tongyeong, 650-160, Republic of Korea
| | - Ji-Min Jung
- Institute of Marine Industry, College of Marine Science, Gyeongsang National University, 455, Tongyeong, 650-160, Republic of Korea
| | - Jee Youn Hwang
- Aquatic Animal Disease Control Center, National Institute of Fisheries Science (NIFS), 216 Gijanghaean-ro, Gijang-eup, Gijang-gun, Busan, 46083, Republic of Korea
| | - Mun-Gyeong Kwon
- Aquatic Animal Disease Control Center, National Institute of Fisheries Science (NIFS), 216 Gijanghaean-ro, Gijang-eup, Gijang-gun, Busan, 46083, Republic of Korea
| | - Jung Soo Seo
- Aquatic Animal Disease Control Center, National Institute of Fisheries Science (NIFS), 216 Gijanghaean-ro, Gijang-eup, Gijang-gun, Busan, 46083, Republic of Korea
| | - Seong Don Hwang
- Aquatic Animal Disease Control Center, National Institute of Fisheries Science (NIFS), 216 Gijanghaean-ro, Gijang-eup, Gijang-gun, Busan, 46083, Republic of Korea
| | - Bo-Yeong Jee
- Aquatic Animal Disease Control Center, National Institute of Fisheries Science (NIFS), 216 Gijanghaean-ro, Gijang-eup, Gijang-gun, Busan, 46083, Republic of Korea
| | - Do-Hyung Kim
- Department of Aquatic Life Medicine, College of Fisheries Science, Pukyong National University, 45, Yongso-ro, Nam-Gu, Busan, Republic of Korea.
| | - Chan-Il Park
- Institute of Marine Industry, College of Marine Science, Gyeongsang National University, 455, Tongyeong, 650-160, Republic of Korea.
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Scholz GM, Heath JE, Aw J, Reynolds EC. Regulation of the Peptidoglycan Amidase PGLYRP2 in Epithelial Cells by Interleukin-36γ. Infect Immun 2018; 86:e00384-18. [PMID: 29914927 PMCID: PMC6105881 DOI: 10.1128/iai.00384-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 06/11/2018] [Indexed: 12/16/2022] Open
Abstract
Interleukin-36 (IL-36) cytokines are important regulators of mucosal homeostasis and inflammation. We have previously established that oral epithelial cells upregulate IL-36γ expression in response to the bacterial pathogen Porphyromonas gingivalis Here, we have established that IL-36γ can stimulate the gene expression of mechanistically distinct antimicrobial proteins, including the peptidoglycan amidase PGLYRP2, in oral epithelial cells (e.g., TIGK cells). PGLYRP2 gene expression was not stimulated by either IL-17 or IL-22, thus demonstrating selectivity in the regulation of PGLYRP2 by IL-36γ. The IL-36γ-inducible expression of PGLYRP2 was shown to be mediated by IRAK1- and p38 mitogen-activated protein (MAP) kinase-dependent signaling. Furthermore, our finding that IL-36γ-inducible PGLYRP2 expression was reduced in proliferating TIGK cells but increased in terminally differentiating cells suggests that control of PGLYRP2 expression is associated with the maturation of the oral epithelium. PGLYRP2 expression in TIGK cells can also be directly stimulated by oral bacteria. However, the extracellular gingipain proteases (Kgp and RgpA/B) produced by P. gingivalis, which are critical virulence factors, can antagonize PGLYRP2 expression. Thus, the expression of IL-36γ by oral epithelial cells in response to P. gingivalis might enable the subsequent autocrine stimulation of PGLYRP2 expression. In summary, our data identify how IL-36γ may promote oral mucosal homeostasis by regulating PGLYRP2 expression.
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Affiliation(s)
- Glen M Scholz
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Jacqueline E Heath
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Jiamin Aw
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Eric C Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, Australia
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K ATP channel block inhibits the Toll-like receptor 2-mediated stimulation of NF-κB by suppressing the activation of Akt, mTOR, JNK and p38-MAPK. Eur J Pharmacol 2017; 815:190-201. [PMID: 28923349 DOI: 10.1016/j.ejphar.2017.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 08/23/2017] [Accepted: 09/12/2017] [Indexed: 11/22/2022]
Abstract
Changes in the KATP channel activity have been shown to regulate inflammation and immune responses. Using human keratinocytes, we investigated the effect of KATP channel inhibition on inflammatory mediator production in relation to the Toll like receptor-2-mediated-Akt, mTOR and NF-κB pathways, as well as JNK and p38-MAPK, which regulate the transcription genes involved in immune and inflammatory responses. 5-Hydroxydecanoate (a selective KATP channel blocker), glibenclamide (a cell surface and mitochondrial KATP channel inhibitor), the Akt inhibitor, rapamycin, Bay 11-7085 and N-acetylcysteine reduced the lipoteichoic acid- or peptidoglycan-induced production of cytokines and chemokines, and production of reactive oxygen species and increased the levels and activities of Kir 6.2, NF-κB, phosphorylated-Akt and mTOR, and the activation of JNK and p38-MAPK in keratinocytes. Inhibitors of c-JNK (SP600125) and p38-MAPK (SB203580) attenuated the lipoteichoic acid- or peptidoglycan-induced production of inflammatory mediators, the activation of the JNK and p38-MAPK, and the production of reactive oxygen species in keratinocytes. The results show that KATP channel blockers may reduce the bacterial component-stimulated production of inflammatory mediators in keratinocytes by suppressing the Toll-like receptor-2-mediated activation of the Akt, mTOR and NF-κB pathways, as well as JNK and p38-MAPK. The suppressive effect of KATP channel blockers appears to be achieved by the inhibition of reactive oxygen species production.
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Functions of Peptidoglycan Recognition Proteins (Pglyrps) at the Ocular Surface: Bacterial Keratitis in Gene-Targeted Mice Deficient in Pglyrp-2, -3 and -4. PLoS One 2015; 10:e0137129. [PMID: 26332373 PMCID: PMC4558058 DOI: 10.1371/journal.pone.0137129] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 08/12/2015] [Indexed: 02/07/2023] Open
Abstract
PURPOSE Functions of antimicrobial peptidoglycan recognition proteins (Pglyrp1-4) at the ocular surface are poorly understood. Earlier, we reported an antibacterial role for Pglyrp-1 in Pseudomonas aeruginosa keratitis. Here we investigated functions of three other related genes Pglyrp-2, -3 and -4 in a mouse model of P. aeruginosa keratitis. METHODS Wild type (WT) and each of the Pglyrp-null genotypes were challenged with P. aeruginosa keratitis. The eyes were scored in a blinded manner 24 and 48h post infection. Viable bacterial counts and inflammatory factors (IL-12, TNF-α, IFN-γ, CCL2, IL-6 and IL-10) were measured in whole eye homogenates using cytometric bead arrays. Expressions of Pglyrp-1-4, mouse beta defensins (mBD)-2,-3, cathelicidin-related antimicrobial peptide (CRAMP) were determined by qRTPCR in total RNA extracts of uninfected and infected eyes of WT and each of the Pglyrp-null mouse types. RESULTS The Pglyrp-2-/- mice showed reduced disease and lower induction of pro-inflammatory TNF-α (p = 0.02) than WT or the other Pglyrp null mice. Viable bacterial yield was significantly lower in the Pglyrp-2-/- (p = 0.0007) and the Pglyrp-4-/- (p = 0.098) mice. With regards to expression of these antimicrobial genes, Pglyrp-2 expression was induced after infection in WT mice. Pglyrp-3 expression was low before and after infection in WT mice, while Pglyrp-4 expression was slightly elevated after infection in WT, Pglyrp-2 and -3 null mice. Pglyrp-1 expression was slightly elevated after infection in all genotypes without statistical significance. Transcripts for antimicrobial peptides mBD2, mBD3 and CRAMP were elevated in infected Pglyrp-2-/- males without statistical significance. CONCLUSIONS Efficient resolution of keratitis in the Pglyrp-2-/- mice may be due to a reduced pro-inflammatory microenvironment and synergistic antibacterial activities of defensins, CRAMP and Pglyrp-1. Therefore, in ocular infections the pro-inflammatory functions of Pglyrp-2 must be regulated to benefit the host.
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Supp DM, Neely AN. Cutaneous antimicrobial gene therapy: engineering human skin replacements to combat wound infection. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/17469872.3.1.73] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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15
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Jang JH, Kim H, Cho JH. Rainbow trout peptidoglycan recognition protein has an anti-inflammatory function in liver cells. FISH & SHELLFISH IMMUNOLOGY 2013; 35:1838-1847. [PMID: 24056276 DOI: 10.1016/j.fsi.2013.09.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/06/2013] [Accepted: 09/06/2013] [Indexed: 06/02/2023]
Abstract
Peptidoglycan recognition proteins (PGRPs) are innate immune molecules that are structurally conserved through evolution in both invertebrate and vertebrate animals. PGRPs exert diverse host-defense functions both through direct antibacterial activity and through indirect effects, including the induction of antimicrobial peptides and the modulation of inflammation and immune responses. In this study, we identified the gene encoding a long form of PGRP (OmPGRP-L1) from the rainbow trout, Oncorhynchus mykiss, and investigated whether it has immunomodulating activity in a rainbow trout hepatoma cell line RTH-149 challenged with fish pathogenic bacteria. OmPGRP-L1 contains the conserved PGRP domain and the four Zn(2+)-binding amino acid residues required for amidase activity. In RTH-149 cells, OmPGRP-L1 expression was increased by bacterial stimulation. Loss-of-function and gain-of-function experiments indicated that OmPGRP-L1 is involved in the expression of pro-inflammatory cytokines. Silencing of OmPGRP-L1 in RTH-149 cells challenged with Edwardsiella tarda dramatically increased the expression of IL-1β and TNF-α. In contrast, overexpression of OmPGRP-L1 or its amidase-inactive mutant OmPGRP-L1(C472S) resulted in down-regulation of IL-1β and TNF-α expression. When overexpressed in RTH-149 cells, OmPGRP-L1 inhibited NF-κB activity with or without bacterial stimulation. Collectively, these findings suggest that OmPGRP-L1 has an anti-inflammatory function, independent of its amidase activity, possibly via NF-κB inhibition in liver cells.
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Affiliation(s)
- Ju Hye Jang
- Department of Biology, Research Institute of Life Science, Gyeongsang National University, 501 Jinju Dae-ro, Jinju 660-701, South Korea
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Kuo IH, Yoshida T, De Benedetto A, Beck LA. The cutaneous innate immune response in patients with atopic dermatitis. J Allergy Clin Immunol 2013; 131:266-78. [PMID: 23374259 DOI: 10.1016/j.jaci.2012.12.1563] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 12/13/2012] [Indexed: 12/28/2022]
Abstract
Orchestrating when and how the cutaneous innate immune system should respond to commensal or pathogenic microbes is a critical function of the epithelium. The cutaneous innate immune system is a key determinant of the physical, chemical, microbial, and immunologic barrier functions of the epidermis. A malfunction in this system can lead to an inadequate host response to a pathogen or a persistent inflammatory state. Atopic dermatitis is the most common inflammatory skin disorder and characterized by abnormalities in both skin barrier structures (stratum corneum and tight junctions), a robust T(H)2 response to environmental antigens, defects in innate immunity, and an altered microbiome. Many of these abnormalities may occur as the consequence of epidermal dysfunction. The epidermis directly interfaces with the environment and, not surprisingly, expresses many pattern recognition receptors that make it a key player in cutaneous innate immune responses to skin infections and injury. This review will discuss the role epidermal innate receptors play in regulation of skin barriers and, where possible, discuss the relevance of these findings for patients with atopic dermatitis.
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Affiliation(s)
- I-Hsin Kuo
- Department of Dermatology, University of Rochester Medical Center, Rochester, NY 14642, USA
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Lu M, Varley AW, Munford RS. Persistently active microbial molecules prolong innate immune tolerance in vivo. PLoS Pathog 2013; 9:e1003339. [PMID: 23675296 PMCID: PMC3649966 DOI: 10.1371/journal.ppat.1003339] [Citation(s) in RCA: 27] [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: 09/04/2012] [Accepted: 03/18/2013] [Indexed: 01/01/2023] Open
Abstract
Measures that bolster the resolution phase of infectious diseases may offer new opportunities for improving outcome. Here we show that inactivation of microbial lipopolysaccharides (LPS) can be required for animals to recover from the innate immune tolerance that follows exposure to Gram-negative bacteria. When wildtype mice are exposed to small parenteral doses of LPS or Gram-negative bacteria, their macrophages become reprogrammed (tolerant) for a few days before they resume normal function. Mice that are unable to inactivate LPS, in contrast, remain tolerant for several months; during this time they respond sluggishly to Gram-negative bacterial challenge, with high mortality. We show here that prolonged macrophage reprogramming is maintained in vivo by the persistence of stimulatory LPS molecules within the cells' in vivo environment, where naïve cells can acquire LPS via cell-cell contact or from the extracellular fluid. The findings provide strong evidence that inactivation of a stimulatory microbial molecule can be required for animals to regain immune homeostasis following parenteral exposure to bacteria. Measures that disable microbial molecules might enhance resolution of tissue inflammation and help restore innate defenses in individuals recovering from many different infectious diseases. We showed previously that mice lacking acyloxyacyl hydrolase (AOAH), the host enzyme that inactivates Gram-negative bacterial lipopolysaccharides (LPS), are unable to regain normal immune responsiveness for many weeks/months after they are exposed in vivo to a small amount of LPS or Gram-negative bacteria. The many possible explanations for slow recovery included long-lasting epigenetic changes in macrophages or other host cells, chronically stimulated cells that produce certain mediators, and persistent signaling by internalized LPS within macrophages. Using several in vivo techniques to study peritoneal macrophages, we found that none of these mechanisms was correct. Rather, prolonged recovery is caused by intact LPS that remains in the environment where macrophages live and can pass from one cell to another in vivo. This is the first evidence that the persistence of a bioactive microbial agonist, per se, can prevent resolution of inflammation in vivo. It also identifies the stimulatory microbial molecule as a realistic target for intervention – in further support, we found that providing recombinant AOAH can be partially preventive. In a larger sense, showing that chemical inactivation of one important microbial signaling molecule is required for full recovery should encourage efforts to find out whether disabling other microbial agonists (chitin, lipopeptides, flagella, others) also benefits infected animals.
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Affiliation(s)
- Mingfang Lu
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
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Clowers JS, Allensworth JJ, Lee EJ, Rosenzweig HL. Investigation of the peptidoglycan sensing molecule, PGLYRP-2, in murine inflammatory uveitis. Br J Ophthalmol 2013; 97:504-10. [PMID: 23361435 DOI: 10.1136/bjophthalmol-2012-302650] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIM Peptidoglycan (PGN) recognition proteins (PGLYRPs) are innate immune molecules that recognise bacterial cell wall PGN, and participate in several inflammatory diseases such as arthritis. We sought to elucidate the contribution of PGLYRPs in murine uveitis (intraocular inflammatory disease) elicited by PGN, and the extent to which systemically administered PGN alters uveitis compared with arthritis versus locally triggered ocular responses. METHODS Mice deficient for PGLYRP-2, PGLYRP-3 or PGLYRP-4 were administered PGN by an intraperitoneal or intraocular injection. Arthritis was assessed by near-infrared imaging and histopathology, while uveitis was measured by intravital videomicroscopy and histopathology. RESULTS Systemic PGN exposure predisposed to arthritis through a PGLYRP-2 dependent mechanism. By contrast, systemic PGN exposure did not predispose to uveitis, and PGLYRP-2 deficiency had no impact on the development the uveitis. When PGN was administered locally, a robust uveitis ensued, which occurred independently of PGLYRP-2. Regardless of whether PGN was administered systemically or locally, neither PGLYRP-3 nor PGLYRP-4 deficiency significantly altered ocular inflammation compared with wild-type control animals. CONCLUSIONS Our findings highlight the complexity of PGLYRPs and how PGLYRP-2 may use different molecular pathways in the joints versus eyes. Collectively, our results support a non-essential or redundant role for PGLYRPs-2, -3, -4 in uveitis.
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Role of mouse peptidoglycan recognition protein PGLYRP2 in the innate immune response to Salmonella enterica serovar Typhimurium infection in vivo. Infect Immun 2012; 80:2645-54. [PMID: 22615249 DOI: 10.1128/iai.00168-12] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Peptidoglycan recognition proteins (PGRPs) are a family of innate pattern recognition molecules that bind bacterial peptidoglycan. While the role of PGRPs in Drosophila innate immunity has been extensively studied, how the four mammalian PGRP proteins (PGLYRP1 to PGLYRP4) contribute to host defense against bacterial pathogens in vivo remains poorly understood. PGLYRP1, PGLYRP3, and PGLYRP4 are directly bactericidal in vitro, whereas PGLYRP2 is an N-acetylmuramyl-L-alanine amidase that cleaves peptidoglycan between the sugar backbone and the peptide stem. Because PGLYRP2 cleaves muramyl peptides detected by host peptidoglycan sensors Nod1 and Nod2, we speculated that PGLYRP2 may act as a modifier of Nod1/Nod2-dependent innate immune responses. We investigated the role of PGLYRP2 in Salmonella enterica serovar Typhimurium-induced colitis, which is regulated by Nod1/Nod2 through the induction of an early Th17 response. PGLYRP2 did not contribute to expression of Th17-associated cytokines, interleukin-22 (IL-22)-dependent antimicrobial proteins, or inflammatory cytokines. However, we found that Pglyrp2-deficient mice displayed significantly enhanced inflammation in the cecum at 72 h postinfection, reflected by increased polymorphonuclear leukocyte (PMN) infiltration and goblet cell depletion. Pglyrp2 expression was also induced in the cecum of Salmonella-infected mice, and expression of green fluorescent protein under control of the Pglyrp2 promoter was increased in discrete populations of intraepithelial lymphocytes. Lastly, Nod2(-/-) Pglyrp2(-/-) mice displayed increased susceptibility to infection at 24 h postinfection compared to Pglyrp2(-/-) mice, which correlated with increased PMN infiltration and submucosal edema. Thus, PGLYRP2 plays a protective role in vivo in the control of S. Typhimurium infection through a Nod1/Nod2-independent mechanism.
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Dziarski R, Kashyap DR, Gupta D. Mammalian peptidoglycan recognition proteins kill bacteria by activating two-component systems and modulate microbiome and inflammation. Microb Drug Resist 2012; 18:280-5. [PMID: 22432705 DOI: 10.1089/mdr.2012.0002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Peptidoglycan recognition proteins (PGRPs) are conserved from insects to mammals and function in antibacterial immunity. We have revealed a novel mechanism of bacterial killing by innate immune system, in which mammalian PGRPs bind to bacterial cell wall or outer membrane and exploit bacterial stress defense response to kill bacteria. PGRPs enter Gram-positive cell wall at the site of daughter cell separation during cell division. In Bacillus subtilis PGRPs activate the CssR-CssS two-component system that detects and disposes of misfolded proteins exported out of bacterial cells. This activation results in membrane depolarization, production of hydroxyl radicals, and cessation of intracellular peptidoglycan, protein, RNA, and DNA synthesis, which are responsible for bacterial death. PGRPs also bind to the outer membrane in Escherichia coli and activate functionally homologous CpxA-CpxR two-component system, which also results in bacterial death. We excluded other potential bactericidal mechanisms, such as inhibition of extracellular peptidoglycan synthesis, hydrolysis of peptidoglycan, and membrane permeabilization. In vivo, mammalian PGRPs are expressed in polymorphonuclear leukocytes, skin, salivary glands, oral cavity, intestinal tract, eyes, and liver. They control acquisition and maintenance of beneficial normal gut microflora, which protects the host from enhanced inflammation, tissue damage, and colitis.
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Affiliation(s)
- Roman Dziarski
- School of Medicine, Indiana University, Gary, Indiana 46408, USA.
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Peptidoglycan recognition proteins: modulators of the microbiome and inflammation. Nat Rev Immunol 2011; 11:837-51. [DOI: 10.1038/nri3089] [Citation(s) in RCA: 259] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Park SY, Gupta D, Hurwich R, Kim CH, Dziarski R. Peptidoglycan recognition protein Pglyrp2 protects mice from psoriasis-like skin inflammation by promoting regulatory T cells and limiting Th17 responses. THE JOURNAL OF IMMUNOLOGY 2011; 187:5813-23. [PMID: 22048773 DOI: 10.4049/jimmunol.1101068] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Skin protects the body from the environment and is an important component of the innate and adaptive immune systems. Psoriasis is a frequent inflammatory skin disease of unknown cause determined by multigenic predisposition, environmental factors, and aberrant immune response. Peptidoglycan recognition proteins (Pglyrps) are expressed in the skin, and we report in this article that they modulate sensitivity in an experimentally induced mouse model of psoriasis. We demonstrate that Pglyrp2(-/-) mice (but not Pglyrp3(-/-) and Pglyrp4(-/-) mice) are more sensitive to the development of 12-O-tetradecanoylphorbol 13-acetate-induced psoriasis-like inflammation, whereas Pglyrp1(-/-) mice are less sensitive. The mechanism underlying this increased sensitivity of Pglyrp2(-/-) mice to 12-O-tetradecanoylphorbol 13-acetate-induced psoriasis-like inflammation is reduced recruitment of regulatory T cells to the skin and enhanced production and activation of Th17 cells in the skin in Pglyrp2(-/-) mice, which results in more severe inflammation and keratinocyte proliferation. Thus, in wild type mice, Pglyrp2 limits overactivation of Th17 cells by promoting accumulation of regulatory T cells at the site of inflammation, which protects the skin from the exaggerated inflammatory response.
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Affiliation(s)
- Shin Yong Park
- Indiana University School of Medicine-Northwest, Gary, IN 46408, USA
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Differential effects of peptidoglycan recognition proteins on experimental atopic and contact dermatitis mediated by Treg and Th17 cells. PLoS One 2011; 6:e24961. [PMID: 21949809 PMCID: PMC3174980 DOI: 10.1371/journal.pone.0024961] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 08/24/2011] [Indexed: 12/31/2022] Open
Abstract
Skin protects the body from the environment and is an important component of the innate and adaptive immune systems. Atopic dermatitis and contact dermatitis are among the most frequent inflammatory skin diseases and are both determined by multigenic predisposition, environmental factors, and aberrant immune response. Peptidoglycan Recognition Proteins (Pglyrps) are expressed in the skin and we report here that they modulate sensitivity to experimentally-induced atopic dermatitis and contact dermatitis. Pglyrp3(-/-) and Pglyrp4(-/-) mice (but not Pglyrp2(-/-) mice) develop more severe oxazolone-induced atopic dermatitis than wild type (WT) mice. The common mechanism underlying this increased sensitivity of Pglyrp3(-/-) and Pglyrp4(-/-) mice to atopic dermatitis is reduced recruitment of Treg cells to the skin and enhanced production and activation Th17 cells in Pglyrp3(-/-) and Pglyrp4(-/-) mice, which results in more severe inflammation and keratinocyte proliferation. This mechanism is supported by decreased inflammation in Pglyrp3(-/-) mice following in vivo induction of Treg cells by vitamin D or after neutralization of IL-17. By contrast, Pglyrp1(-/-) mice develop less severe oxazolone-induced atopic dermatitis and also oxazolone-induced contact dermatitis than WT mice. Thus, Pglyrp3 and Pglyrp4 limit over-activation of Th17 cells by promoting accumulation of Treg cells at the site of chronic inflammation, which protects the skin from exaggerated inflammatory response to cell activators and allergens, whereas Pglyrp1 has an opposite pro-inflammatory effect in the skin.
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Peptidoglycan recognition proteins protect mice from experimental colitis by promoting normal gut flora and preventing induction of interferon-gamma. Cell Host Microbe 2010; 8:147-62. [PMID: 20709292 DOI: 10.1016/j.chom.2010.07.005] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Revised: 01/21/2010] [Accepted: 05/27/2010] [Indexed: 12/18/2022]
Abstract
There are multiple mechanisms that protect the intestine from an excessive inflammatory response to intestinal microorganisms. We report here that all four mammalian peptidoglycan recognition proteins (PGRPs or Pglyrps) protect the host from colitis induced by dextran sulfate sodium (DSS). Pglyrp1(-/-), Pglyrp2(-/-), Pglyrp3(-/-), and Pglyrp4(-/-) mice are all more sensitive than wild-type mice to DSS-induced colitis due to a more inflammatory gut microflora, higher production of interferon-gamma, higher expression of interferon-inducible genes, and an increased number of NK cells in the colon upon initial exposure to DSS, which leads to severe hyperplasia of the lamina propria, loss of epithelial cells, and ulceration in the colon. Thus, during experimental colitis, PGRPs protect the colon of wild-type mice from an early inflammatory response and the loss of the barrier function of intestinal epithelium by promoting normal bacterial flora and by preventing damaging production of interferon-gamma by NK cells in response to injury.
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Dziarski R, Gupta D. Review: Mammalian peptidoglycan recognition proteins (PGRPs) in innate immunity. Innate Immun 2010; 16:168-74. [PMID: 20418257 DOI: 10.1177/1753425910366059] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Peptidoglycan recognition proteins (PGRPs or PGLYRPs) are innate immunity proteins that are conserved from insects to mammals, recognize bacterial peptidoglycan, and function in antibacterial immunity and inflammation. Mammals have four PGRPs - PGLYRP1, PGLYRP2, PGLYRP3, and PGLYRP4. They are secreted proteins expressed in polymorphonuclear leukocytes (PGLYRP1), liver (PGLYRP2), or on body surfaces, mucous membranes, and in secretions (saliva, sweat) (PGLYRP3 and PGLYRP4). All PGRPs recognize bacterial peptidoglycan. Three PGRPs, PGLYRP1, PGLYRP3, and PGLYRP4 are directly bactericidal for both Gram-positive and Gram-negative bacteria and have no enzymatic activity, whereas PGLYRP2 is an N-acetylmuramoyl-L-alanine amidase that hydrolyzes bacterial cell wall peptidoglycan. Peptidoglycan recognition proteins influence host- pathogen interactions not only through their antibacterial or peptidoglycan-hydrolytic properties, but also through their pro-inflammatory and anti-inflammatory properties that are independent of their hydrolytic and antibacterial activities. The PGRPs likely play a role both in antibacterial defenses and several inflammatory diseases. They modulate local inflammatory responses in tissues (such as arthritic joints) and there is evidence for association of PGRPs with inflammatory diseases, such as psoriasis.
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Affiliation(s)
- Roman Dziarski
- Indiana University School of Medicine Northwest, Gary, USA.
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Mao Y, Wang J, Zhang Z, Ding S, Su Y. Cloning, mRNA expression, and recombinant expression of peptidoglycan recognition protein II gene from large yellow croaker (Pseudosciaena crocea). Mol Biol Rep 2010; 37:3897-908. [DOI: 10.1007/s11033-010-0046-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2008] [Accepted: 04/14/2009] [Indexed: 11/28/2022]
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Ghosh A, Lee S, Dziarski R, Chakravarti S. A novel antimicrobial peptidoglycan recognition protein in the cornea. Invest Ophthalmol Vis Sci 2009; 50:4185-91. [PMID: 19387073 PMCID: PMC3052780 DOI: 10.1167/iovs.08-3040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
PURPOSE In an earlier gene expression study, the authors identified a novel antimicrobial gene, Peptidoglycan recognition protein 1 (Pglyrp1), in the mouse cornea. Here the expression of the Pglyrp1 transcript and the encoded protein, PGLYRP1, in the cornea was investigated. The role of PGLYRP1 in the cornea was further investigated using wild-type and Pglyrp1-deficient mice. This is the first report of this antimicrobial protein in the cornea. METHODS PGLYRP1 was detected in the cornea and was further localized to the epithelium by immunohistology, confocal microscopy, immunoblotting, and real-time PCR. The role of PGLYRP1 in the cornea was investigated by comparing the response of wild-type and Pglyrp1(-/-) mice to corneal epithelial wounds and Pseudomonas aeruginosa-mediated corneal infections. The antibacterial effects of corneal PGLYRP1 were assayed by measuring bacterial growth in vitro, in the presence of wild-type corneal epithelial extracts, before and after antibody-mediated blocking of PGLYRP1. RESULTS PGLYRP1 is expressed at high levels in the mouse corneal epithelium. PGLYRP1 was localized to the mouse corneal epithelium and the human corneal epithelium. The Pglyrp1(-/-) mouse shows delayed healing and poor clearing of bacterial keratitis; in vitro its epithelial protein extract shows reduced bacteriostatic activity compared with wild-type mice. CONCLUSIONS PGLYRP1 is a novel antimicrobial protein of the corneal epithelium and protects the ocular surface from bacterial infections.
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Affiliation(s)
- Amit Ghosh
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Seakwoo Lee
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Roman Dziarski
- Department of Immunology and Microbiology, Indiana University School of Medicine-Northwest, Gary, Indiana
| | - Shukti Chakravarti
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Ruíz-González V, Cancino-Diaz JC, Rodríguez-Martínez S, Cancino-Diaz ME. Keratinocytes treated with peptidoglycan fromStaphylococcus aureusproduce vascular endothelial growth factor, and its expression is amplified by the subsequent production of interleukin-13. Int J Dermatol 2009; 48:846-54. [DOI: 10.1111/j.1365-4632.2008.03924.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Saha S, Qi J, Wang S, Wang M, Li X, Kim YG, Núñez G, Gupta D, Dziarski R. PGLYRP-2 and Nod2 are both required for peptidoglycan-induced arthritis and local inflammation. Cell Host Microbe 2009; 5:137-50. [PMID: 19218085 DOI: 10.1016/j.chom.2008.12.010] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 10/06/2008] [Accepted: 12/22/2008] [Indexed: 11/30/2022]
Abstract
Peptidoglycan recognition proteins (PGRPs) are structurally conserved from insects to mammals. Insect PGRPs have diverse host-defense functions. Mammalian PGRPs PGLYRP-1, PGLYRP-3, and PGLYRP-4 have bactericidal activity, while PGLYRP-2 has amidase activity. To extend the known functions of mammalian PGRPs, we examined whether they have immunomodulating activities in peptidoglycan-induced arthritis in mice. We demonstrate that PGLYRP-2 and Nod2 are both required for arthritis in this model. The sequence of events in peptidoglycan-induced arthritis is activation of Nod2, local expression of PGLYRP-2, chemokine production, and recruitment of neutrophils into the limbs, which induces acute arthritis. Only PGLYRP-2 among the four mammalian PGRPs displays this proinflammatory function, and PGLYRP-1 is anti-inflammatory. Toll-like receptor 4 (TLR4) and MyD88 are required for maturation of neutrophils before peptidoglycan challenge. Our results demonstrate that PGRPs, Nod2, and TLR4, representing three different types of pattern-recognition molecules, play interdependent in vivo roles in local inflammation.
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Affiliation(s)
- Sukumar Saha
- Indiana University School of Medicine Northwest, Gary, IN 46408, USA
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Oyoshi MK, He R, Kumar L, Yoon J, Geha RS. Cellular and molecular mechanisms in atopic dermatitis. Adv Immunol 2009; 102:135-226. [PMID: 19477321 DOI: 10.1016/s0065-2776(09)01203-6] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Atopic dermatitis (AD) is a pruritic inflammatory skin disease associated with a personal or family history of allergy. The prevalence of AD is on the rise and estimated at approximately 17% in the USA. The fundamental lesion in AD is a defective skin barrier that results in dry itchy skin, and is aggravated by mechanical injury inflicted by scratching. This allows entry of antigens via the skin and creates a milieu that shapes the immune response to these antigens. This review discusses recent advances in our understanding of the abnormal skin barrier in AD, namely abnormalities in epidermal structural proteins, such as filaggrin, mutated in approximately 15% of patients with AD, epidermal lipids, and epidermal proteases and protease inhibitors. The review also dissects, based on information from mouse models of AD, the contributions of the innate and adaptive immune system to the pathogenesis of AD, including the effect of mechanical skin injury on the polarization of skin dendritic cells, mediated by keratinocyte-derived cytokines such as thymic stromal lymphopoietin (TSLP), IL-6, and IL-1, that results in a Th2-dominated immune response with a Th17 component in acute AD skin lesions and the progressive conversion to a Th1-dominated response in chronic AD skin lesions. Finally, we discuss the mechanisms of susceptibility of AD skin lesions to microbial infections and the role of microbial products in exacerbating skin inflammation in AD. Based on this information, we discuss current and future therapy of this common disease.
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Affiliation(s)
- Michiko K Oyoshi
- Division of Immunology, Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
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Abstract
Antimicrobial proteins constitute a phylogenetically ancient form of innate immunity that provides host defence at skin and mucosal surfaces. Although some components of this system are constitutively expressed, new evidence reviewed in this Progress article shows that the production of certain antimicrobial proteins by epithelial cells can also be regulated by cytokines of the innate and adaptive immune systems. In particular, the effector cytokines interleukin-17 and interleukin-22, which are produced by the T-helper-17-cell subset, are emerging as crucial regulators of antimicrobial-peptide production in the gut and the lungs. This suggests that this T-cell lineage and its cytokines have important roles in skin and mucosal immunity.
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Li X, Wang S, Qi J, Echtenkamp SF, Chatterjee R, Wang M, Boons GJ, Dziarski R, Gupta D. Zebrafish peptidoglycan recognition proteins are bactericidal amidases essential for defense against bacterial infections. Immunity 2007; 27:518-29. [PMID: 17892854 PMCID: PMC2074879 DOI: 10.1016/j.immuni.2007.07.020] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Revised: 06/04/2007] [Accepted: 07/23/2007] [Indexed: 10/22/2022]
Abstract
Peptidoglycan recognition proteins (PGRPs) are structurally conserved through evolution, but their functions in innate immunity are different in invertebrates and vertebrates. We asked what the functions of PGRPs in fish are and whether they are indispensable for defense against infection because fish are the first vertebrates that developed adaptive immunity, but they still rely solely on innate immunity during early development of embryos. We identified and cloned three zebrafish PGRPs and showed that they are highly expressed in eggs, developing embryos, and adult tissues that contact external environment. Zebrafish PGRPs have both peptidoglycan-lytic amidase activity and broad-spectrum bactericidal activity, which is a unique feature. Furthermore, we demonstrated that in the developing zebrafish embryo, one of these PGRPs is essential for defense and survival during bacterial infections. These data demonstrate an absolute requirement for innate immunity in defense against infections in fish embryos and for a PGRP protein for survival in vertebrates.
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Affiliation(s)
- Xinna Li
- Indiana University School of Medicine Northwest, Gary, IN 46408, USA
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Wang M, Liu LH, Wang S, Li X, Lu X, Gupta D, Dziarski R. Human peptidoglycan recognition proteins require zinc to kill both gram-positive and gram-negative bacteria and are synergistic with antibacterial peptides. THE JOURNAL OF IMMUNOLOGY 2007; 178:3116-25. [PMID: 17312159 DOI: 10.4049/jimmunol.178.5.3116] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mammals have four peptidoglycan recognition proteins (PGRPs or PGLYRPs), which are secreted innate immunity pattern recognition molecules with effector functions. In this study, we demonstrate that human PGLYRP-1, PGLYRP-3, PGLYRP-4, and PGLYRP-3:4 have Zn(2+)-dependent bactericidal activity against both Gram-positive and Gram-negative bacteria at physiologic Zn(2+) concentrations found in serum, sweat, saliva, and other body fluids. The requirement for Zn(2+) can only be partially replaced by Ca(2+) for killing of Gram-positive bacteria but not for killing of Gram-negative bacteria. The bactericidal activity of PGLYRPs is salt insensitive and requires N-glycosylation of PGLYRPs. The LD(99) of PGLYRPs for Gram-positive and Gram-negative bacteria is 0.3-1.7 muM, and killing of bacteria by PGLYRPs, in contrast to killing by antibacterial peptides, does not involve permeabilization of cytoplasmic membrane. PGLYRPs and antibacterial peptides (phospholipase A(2), alpha- and beta-defensins, and bactericidal permeability-increasing protein), at subbactericidal concentrations, synergistically kill Gram-positive and Gram-negative bacteria. These results demonstrate that PGLYRPs are a novel class of recognition and effector molecules with broad Zn(2+)-dependent bactericidal activity against both Gram-positive and Gram-negative bacteria that are synergistic with antibacterial peptides.
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Affiliation(s)
- Minhui Wang
- Indiana University School of Medicine, Northwest Campus, 3400 Broadway, Gary, IN 46408, USA
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Royet J, Dziarski R. Peptidoglycan recognition proteins: pleiotropic sensors and effectors of antimicrobial defences. Nat Rev Microbiol 2007; 5:264-77. [PMID: 17363965 DOI: 10.1038/nrmicro1620] [Citation(s) in RCA: 281] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Peptidoglycan recognition proteins (PGRPs) are innate immunity molecules that are present in most invertebrate and vertebrate animals. All PGRPs function in antimicrobial defence and are homologous to the prokaryotic peptidoglycan-lytic type 2 amidases. However, only some PGRPs have the catalytic activity that protects the host from excessive inflammation, and most PGRPs have diversified to carry out other host-defence functions. Insect and mammalian PGRPs defend host cells against infection through very different mechanisms. Insect PGRPs activate signal transduction pathways in host cells or trigger proteolytic cascades in the haemolymph, both of which generate antimicrobial effectors. By contrast, mammalian PGRPs are directly bactericidal. Here, we review these contrasting modes of action.
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Affiliation(s)
- Julien Royet
- Institut de Biologie du Développement de Marseille-Luminy, UMR 6216 CNRS, Université de la Méditérannée Aix-Marseille II, Marseille, France.
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Abstract
Peptidoglycan recognition proteins (PGRPs) are found in insects, mollusks, echinoderms, and vertebrates, and they protect animals against infections. The four mammalian family members are either bactericidal proteins or amidases that hydrolyze bacterial peptidoglycan. Peptidoglycan recognition proteins (PGRPs) are innate immunity molecules present in insects, mollusks, echinoderms, and vertebrates, but not in nematodes or plants. PGRPs have at least one carboxy-terminal PGRP domain (approximately 165 amino acids long), which is homologous to bacteriophage and bacterial type 2 amidases. Insects have up to 19 PGRPs, classified into short (S) and long (L) forms. The short forms are present in the hemolymph, cuticle, and fat-body cells, and sometimes in epidermal cells in the gut and hemocytes, whereas the long forms are mainly expressed in hemocytes. The expression of insect PGRPs is often upregulated by exposure to bacteria. Insect PGRPs activate the Toll or immune deficiency (Imd) signal transduction pathways or induce proteolytic cascades that generate antimicrobial products, induce phagocytosis, hydrolyze peptidoglycan, and protect insects against infections. Mammals have four PGRPs, which are secreted; it is not clear whether any are directly orthologous to the insect PGRPs. One mammalian PGRP, PGLYRP-2, is an N-acetylmuramoyl-L-alanine amidase that hydrolyzes bacterial peptidoglycan and reduces its proinflammatory activity; PGLYRP-2 is secreted from the liver into the blood and is also induced by bacteria in epithelial cells. The three remaining mammalian PGRPs are bactericidal proteins that are secreted as disulfide-linked homo- and hetero-dimers. PGLYRP-1 is expressed primarily in polymorphonuclear leukocyte granules and PGLYRP-3 and PGLYRP-4 are expressed in the skin, eyes, salivary glands, throat, tongue, esophagus, stomach, and intestine. These three proteins kill bacteria by interacting with cell wall peptidoglycan, rather than permeabilizing bacterial membranes as other antibacterial peptides do. Direct bactericidal activity of these PGRPs either evolved in the vertebrate (or mammalian) lineage or is yet to be discovered in insects.
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Affiliation(s)
- Roman Dziarski
- Indiana University School of Medicine-Northwest, Gary, IN 46408, USA.
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Baker BS, Powles A, Fry L. Peptidoglycan: a major aetiological factor for psoriasis? Trends Immunol 2006; 27:545-51. [PMID: 17045843 DOI: 10.1016/j.it.2006.10.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 09/05/2006] [Accepted: 10/02/2006] [Indexed: 12/24/2022]
Abstract
Peptidoglycan (PG), a major cell-wall component of Gram-positive bacteria, has been detected within antigen-presenting cells in various inflammatory conditions, including psoriasis. The additional presence of T-helper 1 cells specific for streptococcal or staphylococcal PG in psoriasis skin lesions implicates PG as an important T-cell stimulator for the disease. PG is a major target for the innate immune system, and associations between genetic polymorphisms of recognition receptors for PG and various auto-inflammatory diseases have been identified. The location of these genes within four linkage sites for psoriasis raises the possibility that an altered innate recognition of PG might contribute to the enhanced T-cell response to the bacterial antigen. These observations suggest that PG is a major aetiological factor for psoriasis and emphasize the importance of PG in bacterial-infection-induced inflammatory disease.
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Affiliation(s)
- Barbara S Baker
- Department of Dermatology, Faculty of Medicine, Imperial College, St Mary's Campus, London W2 1PG, UK.
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Abstract
Peptidoglycan recognition proteins (PGRPs) are innate immunity molecules conserved from insects to mammals. Insects have up to 19 PGRPs, which activate Toll or Imd signal transduction pathways or induce proteolytic cascades that generate antimicrobial products, induce phagocytosis, hydrolyse peptidoglycan, and protect insects against infections. Mammals have four PGRPs, which were hypothesized to function as signal-transducing pattern recognition receptors. However, all mammalian PGRPs are secreted, usually as disulphide-linked homo- and heterodimers. One mammalian PGRP, PGLYRP-2, is an N-acetylmuramoyl-L-alanine amidase that hydrolyses bacterial peptidoglycan and reduces its proinflammatory activity. PGLYRP-2 is secreted from liver into blood, and is also induced by bacteria in epithelial cells. The three remaining mammalian PGRPs are bactericidal or bacteriostatic proteins. PGLYRP-1 is expressed primarily in the granules of polymorphonuclear leucocytes (PMNs) , and PGLYRP-3 and PGLYRP-4 are expressed in the skin, eyes, salivary glands, throat, tongue, esophagus, stomach and intestine, and protect the host against infections. They kill bacteria by interacting with their cell wall peptidoglycan, rather than permeabilizing their membranes. These PGRPs therefore are a new class of bactericidal and bacteriostatic proteins that have different structure, mechanism of action, and expression pattern from currently known vertebrate antimicrobial peptides. Direct bactericidal activity of these PGRPs either evolved in vertebrates or mammals, or it is yet to be discovered in insects.
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Affiliation(s)
- Roman Dziarski
- Indiana University School of Medicine-Northwest, Gary, IN 46408, USA.
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Li X, Wang S, Wang H, Gupta D. Differential expression of peptidoglycan recognition protein 2 in the skin and liver requires different transcription factors. J Biol Chem 2006; 281:20738-20748. [PMID: 16714290 DOI: 10.1074/jbc.m601017200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human peptidoglycan recognition protein 2 (PGLYRP2) is an N-acetylmuramoyl-L-alanine amidase that hydrolyzes bacterial peptidoglycan and is differentially expressed in the two major organs in the human body, liver and skin. PGLYRP2 has a high constitutive expression in the liver but is not expressed in healthy human skin. PGLYRP2 mRNA is also not expressed in cultured human keratinocytes but is highly induced upon exposure to bacteria. In this study we identified the transcription start site for pglyrp2 and demonstrated that the differential expression of PGLYRP2 in hepatocytes and keratinocytes is regulated by different transcription factors whose binding sequences are located in different regions of the pglyrp2 promoter. Induction of pglyrp2 in keratinocytes is regulated by sequences in the distal region of the promoter and requires transcription factors NF-kappaB and Sp1, whereas constitutive expression of pglyrp2 in a hepatocyte cell line is regulated by sequences in the proximal region of the promoter and requires transcription factors c-Jun and ATF2. Regulation of constitutive and inducible expression of pglyrp2 is important for systemic and local innate immune responses to bacterial infections.
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Affiliation(s)
- Xinna Li
- Indiana University School of Medicine-Northwest, Gary, Indiana 46408
| | - Shiyong Wang
- Indiana University School of Medicine-Northwest, Gary, Indiana 46408
| | - Haitao Wang
- Indiana University School of Medicine-Northwest, Gary, Indiana 46408
| | - Dipika Gupta
- Indiana University School of Medicine-Northwest, Gary, Indiana 46408.
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