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Wang DN, Ni JJ, Li JH, Gao YQ, Ni FJ, Zhang ZZ, Fang JY, Lu J, Yao YF. Bacterial infection promotes tumorigenesis of colorectal cancer via regulating CDC42 acetylation. PLoS Pathog 2023; 19:e1011189. [PMID: 36812247 PMCID: PMC9987831 DOI: 10.1371/journal.ppat.1011189] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 03/06/2023] [Accepted: 02/07/2023] [Indexed: 02/24/2023] Open
Abstract
Increasing evidence highlights the role of bacteria in promoting tumorigenesis. The underlying mechanisms may be diverse and remain poorly understood. Here, we report that Salmonella infection leads to extensive de/acetylation changes in host cell proteins. The acetylation of mammalian cell division cycle 42 (CDC42), a member of the Rho family of GTPases involved in many crucial signaling pathways in cancer cells, is drastically reduced after bacterial infection. CDC42 is deacetylated by SIRT2 and acetylated by p300/CBP. Non-acetylated CDC42 at lysine 153 shows an impaired binding of its downstream effector PAK4 and an attenuated phosphorylation of p38 and JNK, consequently reduces cell apoptosis. The reduction in K153 acetylation also enhances the migration and invasion ability of colon cancer cells. The low level of K153 acetylation in patients with colorectal cancer (CRC) predicts a poor prognosis. Taken together, our findings suggest a new mechanism of bacterial infection-induced promotion of colorectal tumorigenesis by modulation of the CDC42-PAK axis through manipulation of CDC42 acetylation.
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Affiliation(s)
- Dan-Ni Wang
- Laboratory of Bacterial Pathogenesis, Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jin-Jing Ni
- Laboratory of Bacterial Pathogenesis, Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian-Hui Li
- Laboratory of Bacterial Pathogenesis, Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Phage, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Ya-Qi Gao
- State Key Laboratory for Oncogenes and Related Genes; Division of Gastroenterology and Hepatology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fang-Jing Ni
- Laboratory of Bacterial Pathogenesis, Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhen-Zhen Zhang
- Department of Pathology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jing-Yuan Fang
- State Key Laboratory for Oncogenes and Related Genes; Division of Gastroenterology and Hepatology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jie Lu
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- * E-mail: (JL); (Y-FY)
| | - Yu-Feng Yao
- Laboratory of Bacterial Pathogenesis, Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Emergency Prevention, Diagnosis and Treatment of Respiratory Infectious Diseases, Shanghai, China
- * E-mail: (JL); (Y-FY)
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Lo Bello F, Ieni A, Hansbro PM, Ruggeri P, Di Stefano A, Nucera F, Coppolino I, Monaco F, Tuccari G, Adcock IM, Caramori G. Role of the mucins in pathogenesis of COPD: implications for therapy. Expert Rev Respir Med 2020; 14:465-483. [PMID: 32133884 DOI: 10.1080/17476348.2020.1739525] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Introduction: Evidence accumulated in the last decade has started to reveal the enormous complexity in the expression, interactions and functions of the large number of different mucins present in the different compartments of the human lower airways. This occurs both in normal subjects and in COPD patients in different clinical phases and stages of severity.Areas covered: We review the known physiological mechanisms that regulate mucin production in human lower airways of normal subjects, the changes in mucin synthesis/secretion in COPD patients and the clinical efficacy of drugs that modulate mucin synthesis/secretion.Expert opinion: It is evident that the old simplistic concept that mucus hypersecretion in COPD patients is associated with negative clinical outcomes is not valid and that the therapeutic potential of 'mucolytic drugs' is under-appreciated due to the complexity of the associated molecular network(s). Likewise, our current knowledge of the effects of the drugs already available on the market that target mucin synthesis/secretion/structure in the lower airways is extremely limited and often indirect and more well-controlled clinical trials are needed in this area.
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Affiliation(s)
- Federica Lo Bello
- Pneumologia, Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali (BIOMORF), Università di Messina, Messina, Italy
| | - Antonio Ieni
- Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", Section of Anatomic Pathology, University of Messina, Messina, Italy
| | - Philip M Hansbro
- Centre for Inflammation, Centenary Institute, Sydney, University of Technology Sydney, Ultimo, Australia
| | - Paolo Ruggeri
- Pneumologia, Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali (BIOMORF), Università di Messina, Messina, Italy
| | - Antonino Di Stefano
- Divisione di Pneumologia e Laboratorio di Citoimmunopatologia dell'Apparato Cardio Respiratorio, Istituti Clinici Scientifici Maugeri, IRCCS, Veruno, Italy
| | - Francesco Nucera
- Pneumologia, Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali (BIOMORF), Università di Messina, Messina, Italy
| | - Irene Coppolino
- Pneumologia, Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali (BIOMORF), Università di Messina, Messina, Italy
| | - Francesco Monaco
- Unità Operativa Semplice Dipartimentale di Chirurgia Toracica, Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali (BIOMORF), AOU Policlinico "G.martino", Messina, Italy
| | - Giovanni Tuccari
- Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", Section of Anatomic Pathology, University of Messina, Messina, Italy
| | - Ian M Adcock
- Airway Disease Section, National Heart and Lung Institute, Imperial College, London, UK
| | - Gaetano Caramori
- Pneumologia, Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali (BIOMORF), Università di Messina, Messina, Italy
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Ramos-Álvarez I, Lee L, Jensen RT. Group II p21-activated kinase, PAK4, is needed for activation of focal adhesion kinases, MAPK, GSK3, and β-catenin in rat pancreatic acinar cells. Am J Physiol Gastrointest Liver Physiol 2020; 318:G490-G503. [PMID: 31984786 PMCID: PMC7099487 DOI: 10.1152/ajpgi.00229.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
PAK4 is the only member of the Group II p21-activated kinases (PAKs) present in rat pancreatic acinar cells and is activated by gastrointestinal hormones/neurotransmitters stimulating PLC/cAMP and by various pancreatic growth factors. However, little is known of the role of PAK4 activation in cellular signaling cascades in pancreatic acinar cells. In the present study, we examined the role of PAK4's participation in five different cholecystokinin-8 (CCK-8)-stimulated signaling pathways (PI3K/Akt, MAPK, focal adhesion kinase, GSK3, and β-catenin), which mediate many of its physiological acinar-cell effects, as well as effects in pathophysiological conditions. To define PAK4's role, the effect of two different PAK4 inhibitors, PF-3758309 and LCH-7749944, was examined under experimental conditions that only inhibited PAK4 activation and not activation of the other pancreatic PAK, Group I PAK2. The inhibitors' effects on activation of these five signaling cascades by both physiological and pathophysiological concentrations of CCK, as well as by 12-O-tetradecanoylphobol-13-acetate (TPA), a PKC-activator, were examined. CCK/TPA activation of focal adhesion kinases(PYK2/p125FAK) and the accompanying adapter proteins (paxillin/p130CAS), Mek1/2, and p44/42, but not c-Raf or other MAPKs (JNK/p38), were mediated by PAK4. Activation of PI3K/Akt/p70s6K was independent of PAK4, whereas GSK3 and β-catenin stimulation was PAK4-dependent. These results, coupled with recent studies showing PAK4 is important in pancreatic fluid/electrolyte/enzyme secretion and acinar cell growth, show that PAK4 plays an important role in different cellular signaling cascades, which have been shown to mediate numerous physiological and pathophysiological processes in pancreatic acinar cells.NEW & NOTEWORTHY In pancreatic acinar cells, cholecystokinin (CCK) or 12-O-tetradecanoylphobol-13-acetate (TPA) activation of focal adhesion kinases (p125FAK,PYK2) and its accompanying adapter proteins, p130CAS/paxillin; Mek1/2, p44/42, GSK3, and β-catenin are mediated by PAK4. PI3K/Akt/p70s6K, c-Raf, JNK, or p38 pathways are independent of PAK4 activation.
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Affiliation(s)
- Irene Ramos-Álvarez
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Lingaku Lee
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Robert T. Jensen
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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4
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Ramos-Alvarez I, Jensen RT. P21-activated kinase 4 in pancreatic acinar cells is activated by numerous gastrointestinal hormones/neurotransmitters and growth factors by novel signaling, and its activation stimulates secretory/growth cascades. Am J Physiol Gastrointest Liver Physiol 2018; 315:G302-G317. [PMID: 29672153 PMCID: PMC6139648 DOI: 10.1152/ajpgi.00005.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 04/06/2018] [Accepted: 04/12/2018] [Indexed: 01/31/2023]
Abstract
p21-activated kinases (PAKs) are highly conserved serine/threonine protein kinases, which are divided into two groups: group-I (PAKs1-3) and group-II (PAKs4-6). In various tissues, Group-II PAKs play important roles in cytoskeletal dynamics and cell growth as well as neoplastic development/progression. However, little is known about Group-II PAK's role in a number of physiological events, including their ability to be activated by gastrointestinal (GI) hormones/neurotransmitters/growth factors (GFs). We used rat pancreatic acini to explore the ability of GI hormones/neurotransmitters/GFs to activate Group-II-PAKs and the signaling cascades involved. Only PAK4 was detected in pancreatic acini. PAK4 was activated by endothelin, secretagogues-stimulating phospholipase C (bombesin, CCK-8, and carbachol), by pancreatic GFs (insulin, insulin-like growth factor 1, hepatocyte growth factor, epidermal growth factor, basic fibroblast growth factor, and platelet-derived growth factor), and by postreceptor stimulants (12-O-tetradecanoylphobol-13-acetate and A23187 ). CCK-8 activation of PAK4 required both high- and low-affinity CCK1-receptor state activation. It was reduced by PKC-, Src-, p44/42-, or p38-inhibition but not with phosphatidylinositol 3-kinase-inhibitors and only minimally by thapsigargin. A protein kinase D (PKD)-inhibitor completely inhibited CCK-8-stimulated PKD-activation; however, stimulated PAK4 phosphorylation was only inhibited by 60%, demonstrating that it is both PKD-dependent and PKD-independent. PF-3758309 and LCH-7749944, inhibitors of PAK4, decreased CCK-8-stimulated PAK4 activation but not PAK2 activation. Each inhibited ERK1/2 activation and amylase release induced by CCK-8 or bombesin. These results show that PAK4 has an important role in modulating signal cascades activated by a number of GI hormones/neurotransmitters/GFs that have been shown to mediate both physiological/pathological responses in acinar cells. Therefore, in addition to the extensive studies on PAK4 in pancreatic cancer, PAK4 should also be considered an important signaling molecule for pancreatic acinar physiological responses and, in the future, should be investigated for a possible role in pancreatic acinar pathophysiological responses, such as in pancreatitis. NEW & NOTEWORTHY This study demonstrates that the only Group-II p21-activated kinase (PAK) in rat pancreatic acinar cells is PAK4, and thus differs from islets/pancreatic cancer. Both gastrointestinal hormones/neurotransmitters stimulating PLC and pancreatic growth factors activate PAK4. With cholecystokinin (CCK), activation is PKC-dependent/-independent, requires both CCK1-R affinity states, Src, p42/44, and p38 activation. PAK4 activation is required for CCK-mediated p42/44 activation/amylase release. These results show PAK4 plays an important role in mediating CCK physiological signal cascades and suggest it may be a target in pancreatic acinar diseases besides cancer.
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Affiliation(s)
- Irene Ramos-Alvarez
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland
| | - R T Jensen
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland
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Li JD, Hermansson A, Ryan AF, Bakaletz LO, Brown SD, Cheeseman MT, Juhn SK, Jung TTK, Lim DJ, Lim JH, Lin J, Moon SK, Post JC. Panel 4: Recent advances in otitis media in molecular biology, biochemistry, genetics, and animal models. Otolaryngol Head Neck Surg 2013; 148:E52-63. [PMID: 23536532 DOI: 10.1177/0194599813479772] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Otitis media (OM) is the most common childhood bacterial infection and also the leading cause of conductive hearing loss in children. Currently, there is an urgent need for developing novel therapeutic agents for treating OM based on full understanding of molecular pathogenesis in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM. OBJECTIVE To provide a state-of-the-art review concerning recent advances in OM in the areas of molecular biology, biochemistry, genetics, and animal model studies and to discuss the future directions of OM studies in these areas. DATA SOURCES AND REVIEW METHODS A structured search of the current literature (since June 2007). The authors searched PubMed for published literature in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM. RESULTS Over the past 4 years, significant progress has been made in the areas of molecular biology, biochemistry, genetics, and animal model studies in OM. These studies brought new insights into our understanding of the molecular and biochemical mechanisms underlying the molecular pathogenesis of OM and helped identify novel therapeutic targets for OM. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE Our understanding of the molecular pathogenesis of OM has been significantly advanced, particularly in the areas of inflammation, innate immunity, mucus overproduction, mucosal hyperplasia, middle ear and inner ear interaction, genetics, genome sequencing, and animal model studies. Although these studies are still in their experimental stages, they help identify new potential therapeutic targets. Future preclinical and clinical studies will help to translate these exciting experimental research findings into clinical applications.
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Affiliation(s)
- Jian-Dong Li
- Center for Inflammation, Immunity & Infection, and Department of Biology, Georgia State University, Atlanta, Georgia 30303, USA.
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6
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Kim JH, Park DK, Lee CH, Yoon DY. A new isoflavone glycitein 7-O-beta-D-glucoside 4''-O-methylate, isolated from Cordyceps militaris grown on germinated soybeans extract, inhibits EGF-induced mucus hypersecretion in the human lung mucoepidermoid cells. Phytother Res 2012; 26:1807-12. [PMID: 22407817 DOI: 10.1002/ptr.4655] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 01/26/2012] [Accepted: 02/01/2012] [Indexed: 12/11/2022]
Abstract
A new isoflavone glycitein 7-O-beta-d-glucoside 4''-O-methylate (CGLM) has been isolated recently from Cordyceps militaris grown on germinated soybean extract and has antioxidant activity. In the present study, CGLM was investigated for its suppression of airway mucous hyper-secretion in epidermal growth factor (EGF)-treated human lung mucoepidermoid cells. NCI-H292 cells were treated with CGLM for 1 h, followed by EGF treatment for 24 h. The decrease in cyclooxygenase-2 (COX-2) production was correlated with reduced levels of protein and mRNA of inducible matrix metalloproteinase 9 (MMP-9) and also MUC5AC gene expression. CGLM directly inhibited down-regulated NF-κB activity, and significantly inhibited the phosphorylation of p38 and ERK1/2 (p42/p44) in NCI-H292 cells. These results suggest that CGLM protects NCI-H292 cells from EGF-induced damage by down-regulation of COX-2, MMP-9 and MUC5AC gene expression, mediated via blocking the NF-kappa-B and p38/ERK MAPK pathways.
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Affiliation(s)
- Jung-Hee Kim
- Department of Bioscience and Biotechnology, BIMC, Konkuk University, Seoul 143-701, Republic of Korea
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Lee J, Komatsu K, Lee BC, Lim JH, Jono H, Xu H, Kai H, Zhang ZJ, Yan C, Li JD. Phosphodiesterase 4B mediates extracellular signal-regulated kinase-dependent up-regulation of mucin MUC5AC protein by Streptococcus pneumoniae by inhibiting cAMP-protein kinase A-dependent MKP-1 phosphatase pathway. J Biol Chem 2012; 287:22799-811. [PMID: 22610099 DOI: 10.1074/jbc.m111.337378] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Otitis media (OM) is the most common childhood bacterial infection and the major cause of conductive hearing loss in children. Mucus overproduction is a hallmark of OM. Streptococcus pneumoniae is the most common gram-positive bacterial pathogen causing OM. Among many mucin genes, MUC5AC has been found to be greatly up-regulated in the middle ear mucosa of human patients with OM. We previously reported that S. pneumoniae up-regulates MUC5AC expression in a MAPK ERK-dependent manner. We also found that MAPK phosphatase-1 (MKP-1) negatively regulates S. pneumoniae-induced ERK-dependent MUC5AC up-regulation. Therapeutic strategies for up-regulating the expression of negative regulators such as MKP-1 may have significant therapeutic potential for treating mucus overproduction in OM. However, the underlying molecular mechanism by which MKP-1 expression is negatively regulated during S. pneumoniae infection is unknown. In this study we show that phosphodiesterase 4B (PDE4B) mediates S. pneumoniae-induced MUC5AC up-regulation by inhibiting the expression of a negative regulator MKP-1, which in turn leads to enhanced MAPK ERK activation and subsequent up-regulation of MUC5AC. PDE4B inhibits MKP-1 expression in a cAMP-PKA-dependent manner. PDE4-specific inhibitor rolipram inhibits S. pneumoniae-induced MUC5AC up-regulation both in vitro and in vivo. Moreover, we show that PDE4B plays a critical role in MUC5AC induction. Finally, topical and post-infection administration of rolipram into the middle ear potently inhibited S. pneumoniae-induced MUC5AC up-regulation. Collectively, these data demonstrate that PDE4B mediates ERK-dependent up-regulation of mucin MUC5AC by S. pneumoniae by inhibiting cAMP-PKA-dependent MKP-1 pathway. This study may lead to novel therapeutic strategy for inhibiting mucus overproduction.
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Affiliation(s)
- Jiyun Lee
- Center for Inflammation, Immunity, and Infection and Department of Biology, Georgia State University, Atlanta, Georgia 30303, USA
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8
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Jono H, Lim JH, Xu H, Li JD. PKCθ synergizes with TLR-dependent TRAF6 signaling pathway to upregulate MUC5AC mucin via CARMA1. PLoS One 2012; 7:e31049. [PMID: 22303480 PMCID: PMC3267763 DOI: 10.1371/journal.pone.0031049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Accepted: 12/30/2011] [Indexed: 01/09/2023] Open
Abstract
CARD-containing MAGUK protein 1 (CARMA1) plays a crucial role in regulating adaptive immune responses upon T-cell receptor (TCR) activation in T cells. Its role in regulating host mucosal innate immune response such as upregulation of mucin remains unknown. Here we show that CARMA1 acts as a key signaling mediator for synergistic upregulation of MUC5AC mucin by bacterium nontypeable Haemophilus influenzae (NTHi) and phorbol ester PMA in respiratory epithelial cells. NTHi-induced TLR-dependent TRAF6-MKK3-p38 MAPK signaling pathway synergizes with PKCθ-MEK-ERK signaling pathway. CARMA1 plays a crucial role in mediating this synergistic effect via TRAF6, thereby resulting in synergistic upregulation of MUC5AC mucin. Thus our study unveils a novel role for CARMA1 in mediating host mucosal innate immune response.
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Affiliation(s)
- Hirofumi Jono
- Department of Microbiology & Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Jae Hyang Lim
- Department of Microbiology & Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
- Center for Inflammation, Immunity & Infection, and Department of Biology, Georgia State Universtity, Atlanta, Georgia, United States of America
| | - Haidong Xu
- Department of Microbiology & Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
- Center for Inflammation, Immunity & Infection, and Department of Biology, Georgia State Universtity, Atlanta, Georgia, United States of America
| | - Jian-Dong Li
- Department of Microbiology & Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
- Center for Inflammation, Immunity & Infection, and Department of Biology, Georgia State Universtity, Atlanta, Georgia, United States of America
- * E-mail:
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Ren D, Daines DA. Use of the EpiAirway model for characterizing long-term host-pathogen interactions. J Vis Exp 2011:e3261. [PMID: 21912369 DOI: 10.3791/3261] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) are human-adapted Gram-negative bacteria that can cause recurrent and chronic infections of the respiratory mucosa (1; 2). To study the mechanisms by which these organisms survive on and inside respiratory tissues, a model in which successful long-term co-culture of bacteria and human cells can be performed is required. We use primary human respiratory epithelial tissues raised to the air-liquid interface, the EpiAirway model (MatTek, Ashland, MA). These are non-immortalized, well-differentiated, 3-dimensional tissues that contain tight junctions, ciliated and nonciliated cells, goblet cells that produce mucin, and retain the ability to produce cytokines in response to infection. This biologically relevant in vitro model of the human upper airway can be used in a number of ways; the overall goal of this method is to perform long-term co-culture of EpiAirway tissues with NTHi and quantitate cell-associated and internalized bacteria over time. As well, mucin production and the cytokine profile of the infected co-cultures can be determined. This approach improves upon existing methods in that many current protocols use submerged monolayer or Transwell cultures of human cells, which are not capable of supporting bacterial infections over extended periods(3). For example, if an organism can replicate in the overlying media, this can result in unacceptable levels of cytotoxicity and loss of host cells, arresting the experiment. The EpiAirway model allows characterization of long-term host-pathogen interactions. Further, since the source for the EpiAirway is normal human tracheo-bronchial cells rather than an immortalized line, each is an excellent representation of actual human upper respiratory tract tissue, both in structure and in function(4). For this method, the EpiAirway tissues are weaned off of anti-microbial and anti-fungal compounds for 2 days prior to delivery, and all procedures are performed under antibiotic-free conditions. This necessitates special considerations, since both bacteria and primary human tissues are used in the same biosafety cabinet, and are co-cultured for extended periods.
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Affiliation(s)
- Dabin Ren
- Division of Basic Medical Sciences, Mercer University School of Medicine
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10
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Baldassa S, Calogero AM, Colombo G, Zippel R, Gnesutta N. N-terminal interaction domain implicates PAK4 in translational regulation and reveals novel cellular localization signals. J Cell Physiol 2010; 224:722-33. [DOI: 10.1002/jcp.22172] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Abstract
The Rho-family GTPases Rho Rac and Cdc42 regulate many intracellular processes through their interaction with downstream effector proteins. The PAKs (p21-activated kinases) are a family of effector proteins for Rac and Cdc42. PAKs are important regulators of actin cytoskeletal dynamics, neurite outgrowth, cell survival, hormone signalling and gene transcription. There are six mammalian PAKs that can be divided into two groups: group I PAKs (PAK1-3) and group II PAKs (PAK4-6). Although the two PAK groups are architecturally similar, there are differences in their mode of regulation, suggesting that their cellular functions are likely to be different. Whereas much is known about group I PAKs, less is known about the more recently discovered PAK4, PAK5 and PAK6. This review will focus on the latest structural and functional results relating to the group II PAKs and discuss the emerging importance of group II PAKs in disease progression.
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Ha UH, Lim JH, Kim HJ, Wu W, Jin S, Xu H, Li JD. MKP1 regulates the induction of MUC5AC mucin by Streptococcus pneumoniae pneumolysin by inhibiting the PAK4-JNK signaling pathway. J Biol Chem 2008; 283:30624-31. [PMID: 18782768 DOI: 10.1074/jbc.m802519200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Mucosal epithelial cells in the respiratory tract act as the first line of host innate defense against inhaled microbes by producing a range of molecules for clearance. In particular, epithelial mucins facilitate the mucociliary clearance by physically trapping the inhaled microbes. Up-regulation of mucin production thus represents an important host innate defense response against invading microbes. Excess mucin production, however, overwhelms the mucociliary clearance, resulting in defective mucosal defenses. Thus, tight regulation of mucin production is critical for maintaining an appropriate balance between beneficial and detrimental outcomes. Among various mechanisms, negative regulation plays an important role in tightly regulating mucin production. Here we show that the PAK4-JNK signaling pathway acted as a negative regulator for Streptococcus pneumoniae pneumolysin-induced MUC5AC mucin transcription. Moreover pneumolysin also selectively induced expression of MKP1 via a TLR4-dependent MyD88-TRAF6-ERK signaling pathway, which inhibited the PAK4-JNK signaling pathway, thereby leading to up-regulation of MUC5AC mucin production to maintain effective mucosal protection against S. pneumoniae infection. These studies provide novel insights into the molecular mechanisms underlying the tight regulation of mucin overproduction in the pathogenesis of airway infectious diseases and may lead to development of new therapeutic strategies.
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Affiliation(s)
- Un-Hwan Ha
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642, USA
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