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Relationship between growth factors and its implication in the pathogenesis of leprosy. Microb Pathog 2014; 77:66-72. [PMID: 25457797 DOI: 10.1016/j.micpath.2014.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 10/07/2014] [Accepted: 10/15/2014] [Indexed: 11/23/2022]
Abstract
Leprosy is a chronic infectious disease caused by Mycobacterium leprae which affects the skin and peripheral nervous system. The immune response of the host determines the clinical course of the disease. The tuberculoid form is the result of high cell-mediated immunity characterized by a Th1 response, whereas the lepromatous form is characterized by low cell-mediated immunity and a Th2 humoral response. The neural damage established produces marked changes in the expression of growth factors such as nerve growth factor (NGF) and its receptors (NGF-R). The expression of NGF, associated with the expression of Th1 and Th2 cytokines, might be involved in the tissue damage caused by the bacillus. Therefore, the objective of this study was to correlate the immunoexpression patterns of NGF and NGF-R in the different clinical forms of leprosy, and to associate the findings with the in situ expression of TGF-β and clinical classification of the disease. TGF-β, NGF and NGF-R immunoexpression was analyzed by immunohistochemistry in paraffin-embedded material. Most patients were males with a mean age of 40.7 years. TGF-β levels were significantly higher in the lepromatous forms. No significant difference in the immunoexpression of NGF or NGF-R was observed between the clinical forms, but expression tended to be higher at the lepromatous pole. There was a significant positive correlation between NGF and NGF-R in the different clinical forms of leprosy. A significant positive correlation was observed between NGF, NGF-R and TGF-β. It can be concluded that, even existing evidence on the role of these molecules in the clinical spectrum of leprosy.
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Costa RD, Mendonça VA, Soriani FM, Lyon S, Penido RA, Costa AMDD, Costa MD, Terra FDS, Teixeira MM, Antunes CMDF, Teixeira AL. Serial measurement of the circulating levels of tumour necrosis factor and its soluble receptors 1 and 2 for monitoring leprosy patients during multidrug treatment. Mem Inst Oswaldo Cruz 2014; 108:1051-6. [PMID: 24402158 PMCID: PMC4005550 DOI: 10.1590/0074-0276130240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 09/26/2013] [Indexed: 11/24/2022] Open
Abstract
Leprosy is an infectious and contagious spectral disease accompanied by a series of
immunological events triggered by the host response to the aetiologic agent,
Mycobacterium leprae . The induction and maintenance of the
immune/inflammatory response in leprosy are linked to multiple cell interactions and
soluble factors, primarily through the action of cytokines. The purpose of the
present study was to evaluate the serum levels of tumour necrosis factor (TNF)-α and
its soluble receptors (sTNF-R1 and sTNF-R2) in leprosy patients at different stages
of multidrug treatment (MDT) in comparison with non-infected individuals and to
determine their role as putative biomarkers of the severity of leprosy or the
treatment response. ELISA was used to measure the levels of these molecules in 30
healthy controls and 37 leprosy patients at the time of diagnosis and during and
after MDT. Our results showed increases in the serum levels of TNF-α and sTNF-R2 in
infected individuals in comparison with controls. The levels of TNF-α, but not
sTNF-R2, decreased with treatment. The current results corroborate previous reports
of elevated serum levels of TNF-α in leprosy and suggest a role for sTNF-R2 in the
control of this cytokine during MDT.
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Affiliation(s)
- Rosane Dias Costa
- Santa Casa de Misericórdia de Belo Horizonte, Belo HorizonteMG, Brasil
| | - Vanessa Amaral Mendonça
- Laboratório de Inflamação e Metabolismo, Universidade Federal dos Vales do Jequitinhonha e Mucuri, DiamantinaMG, Brasil
| | - Frederico Marianetti Soriani
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo HorizonteMG, Brasil
| | - Sandra Lyon
- Universidade José do Rosário Vellano, AlfenasMG, Brasil
| | - Rachel Adriana Penido
- Hospital Eduardo de Menezes, Fundação Hospitalar do Estado de Minas Gerais, Belo HorizonteMG, Brasil
| | | | - Marina Dias Costa
- Santa Casa de Misericórdia de Belo Horizonte, Belo HorizonteMG, Brasil
| | | | - Mauro Martins Teixeira
- Laboratório Interdisciplinar de Investigação Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo HorizonteMG, Brasil
| | | | - Antonio Lúcio Teixeira
- Laboratório Interdisciplinar de Investigação Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo HorizonteMG, Brasil
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Antônio JR, Soubhia RMC, Paschoal VDA, Amarante CF, Travolo ARF. Biological agents: investigation into leprosy and other infectious diseases before indication. An Bras Dermatol 2013; 88:23-5. [PMID: 24346871 PMCID: PMC3875992 DOI: 10.1590/abd1806-4841.20132187] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 12/22/2012] [Indexed: 11/22/2022] Open
Abstract
Biological agents are widely used for various immune-mediated diseases, with remarkable effectiveness in the treatment of rheumatoid arthritis (RA), psoriasis, psoriatic arthritis, ankylosing spondylitis and Crohn's disease. However, attention needs to be drawn to the adverse effects of these therapies and the risk of reactivating underlying granulomatous infectious diseases such as tuberculosis, leprosy, syphilis, leishmaniasis, among others. The objective of this paper is to describe a case of leprosy in a patient with RA using anti-TNF alfa, demonstrating the need for systematic investigation of skin lesions suggestive of leprosy in patients who require rheumatoid arthritis therapeutic treatment, especially in endemic regions like Brazil.
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Affiliation(s)
- João Roberto Antônio
- Professor Emeritus and Doctor at the State Medical School of São José
do Rio Preto (FAMERP) - Head of Dermatology at the State Medical School of São José do
Rio Preto and the Dermatology Department of the Base Hospital of São José do Rio Preto -
São José do Rio Preto (SP), Brazil
| | - Rosa Maria Cordeiro Soubhia
- PhD in Health Sciences - Adjunct Professor of Dermatology at the State
Medical School of São José do Rio Preto (FAMERP) - São José do Rio Preto (SP),
Brazil
| | - Vania Del Arco Paschoal
- PhD in Health Sciences - Adjunct Professor in the Department of Health
Nursing at the State Medical School of São José do Rio Preto (FAMERP) - São José do Rio
Preto (SP), Brazil
| | - Carolina Forte Amarante
- Resident Doctor - Resident at the Medical Clinic at the Base Hospital
of the Regional Medical School Foundation (FUNFARME) - São José do Rio Preto (SP),
Brazil
| | - Ana Regina Franchi Travolo
- Dermatologist - Specialist in Dermatology - Residency in Dermatology
from the Base Hospital of the Regional Medical School Foundation (FUNFARME) - São José
do Rio Preto (SP), Brazil
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Costa RD, Mendonça VA, Penido RA, Lyon S, Costa AMDD, Costa MD, Terra FDS, Bretas TL, Antunes CMDF, Teixeira AL. Study of the profile of the neurotrophin BDNF in new leprosy cases before, during and after multidrug therapy. ARQUIVOS DE NEURO-PSIQUIATRIA 2011; 69:100-4. [PMID: 21359431 DOI: 10.1590/s0004-282x2011000100019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Accepted: 08/18/2010] [Indexed: 12/20/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is a neurotrophin involved in the survival of neurons and growth and differentiation of dendrites and axons. The purpose of the present study was to evaluate plasma levels of BDNF of leprosy patients at different stages of multidrug therapy (MDT) in comparison with non-infected individuals. Plasma levels of BDNF were measured by ELISA in 30 healthy controls and 37 leprosy patients at diagnosis, during and after MDT. Plasma levels of BDNF tended to be higher in control subjects in comparison with leprosy patients, but this difference does not reach statistical significance. Interestingly, BDNF levels changed following MDT, achieving statistical difference only at the 2nd dose of MDT. These results indicate that BDNF may not be a surrogate marker of leprosy infection and/or related neuropathy. Further research is needed to investigate the meaning of BDNF level changes following leprosy treatment.
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Costa RD, Mendonça VA, Lyon S, Penido RA, Costa AMDD, Costa MD, Nishi MP, Teixeira MM, Teixeira AL, Antunes CMDF. Evaluation of the expression of interleukin 1 beta (IL-1beta) and interleukin 1 receptor antagonist (IL-1Ra) in leprosy patients. Rev Soc Bras Med Trop 2009; 41 Suppl 2:99-103. [PMID: 19618085 DOI: 10.1590/s0037-86822008000700020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Leprosy is an infectious and contagious spectral disease accompanied by a series of immunological events triggered by the host's response to the etiologic agent, Mycobacterium leprae. Evidence suggests that the induction and maintenance of the immune/inflammatory response in leprosy are linked to multiple cell interactions and soluble factors, mainly through the action of cytokines. The ELISA test was used to measure the levels of IL-1beta and IL-1Ra in 37 new leprosy patients followed-up during treatment and 30 healthy controls. Peripheral blood was collected four times during the treatment of leprosy patients (MDT pretreatment, 2nd dose, 6th dose and post-MDT), and only once from the controls. The comparison of molecular levels in pre-MDT patients and controls showed a statistically significant difference for IL-1beta. The results suggest the participation of this cytokine in the genesis of the immune/inflammatory process.
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Lyon AC, Teixeira MM, Araújo SA, Pereira MCN, Pedroso ERP, Teixeira AL. Serum levels of sTNF-R1, sTNF-R2 and CXCL9 correlate with disease activity in adult type paracoccidioidomycosis. Acta Trop 2009; 109:213-8. [PMID: 19083989 DOI: 10.1016/j.actatropica.2008.11.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Revised: 10/16/2008] [Accepted: 11/14/2008] [Indexed: 11/16/2022]
Abstract
Paracoccidioidomycosis (PCM) is the most common systemic mycosis in Latin America. A major problem in the management of PCM is to determine the best time to discontinue therapy due to the high relapse rate among patients. Soluble TNF receptors (sTNF-R) levels and chemokines are associated with disease activity in several infectious, inflammatory and autoimmune disorders. The aim of the present work was to evaluate levels of sTNF-R1, sTNF-R2 and chemokines in serum of patients with adult type of PCM, before and after antifungal therapy, and to correlate those levels to disease activity. Concentrations of sTNF-R1, sTNF-R2 and CXCL9 were higher in untreated patients and decreased progressively with treatment. The serum marker with the best accuracy to discriminate PCM cases from controls was sTNF-R2. sTNF-R1 did not drop to control levels before 36 months of treatment. CCL2 and CCL3 levels were low at baseline in PCM patients, raised significantly after 12 months of treatment and diminished thereafter. CCL24 levels were higher after 36 months of antifungal therapy in PCM patients. CCL11 levels were not statistically different from control subjects. sTNF-R1, sTNF-R2 and CXCL9 may be useful as laboratory parameters to assess disease activity in PCM patients.
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Affiliation(s)
- Ana C Lyon
- Department of Internal Medicine, Faculty of Medicine, Federal University of Minas Gerais, Avenida Alfredo Balena 190, Santa Efigênia, Belo Horizonte, MG, Brazil
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Sabry A, Elbasyouni SR, Sheashaa HA, Alhusseini AA, Mahmoud K, George SK, Kaleek EA, abo-Zena H, Kalil AM, Mohsen T, Rahim MA, El-samanody AZ. Correlation between levels of TNF-alpha and IL-6 and hematological involvement in SLE Egyptian patients with lupus nephritis. Int Urol Nephrol 2007; 38:731-7. [PMID: 17260180 DOI: 10.1007/s11255-006-0047-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Accepted: 02/10/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND Systemic lupus Erythematosus (SLE) is a rheumatic autoimmune disease characterized by multisystem organ involvement and by high titers of auto antibodies against several nuclear and cytoplasmic antigens. Numerous abnormalities of the cytokine network have been described in patients suffering from SLE. However the role of cytokines in different organ involvement is not yet well defined. OBJECTIVE To determine if levels of Interlukin-6 (IL-6) and Tumor necrosis factor (TNF-alpha) correlate with SLE disease activity in Egyptian SLE patients and more specifically with hematological involvement. METHODS Levels of TNF-alpha and IL-6 in serum samples from sixty individuals (40 with Systemic lupus Erythmatosus and 20 healthy controls) were determined and renal biopsies were obtained from SLE patients. RESULTS Levels of TNF-alpha and IL-6 were higher in SLE patients with active compared with inactive hematological disease. Further analysis showed that this association was dependent on inverse correlation (P=0.017, r=-0.49) for IL-6 and (P=0.76, r=-.243) for TNF-alpha. The mean level of TNF-alpha and Il-6 was (766.95+/-357.82 pg/ml) and (135.4+/-54.23 pg/ml) respectively for patients with active disease while it was (314.01+/-100.87 pg/ml) and (47.33+/-18.61 pg/ml) for those with inactive disease and (172.7+/-39.19 pg/ml) and (21.15+/-10.99 pg/ml) for the healthy control group respectively. The difference was statistically significant (P=0.002). We found significant positive correlations between TNF-alpha and IL-6 and the SLE Disease Activity Index (SLEDAI) score. (r=+0.743 and +0.772 respectively). CONCLUSION Raised level of Il-6 and TNF-alpha may influence the development of anemia in Egyptian patients with Lupus Nephritis.
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Affiliation(s)
- Alaa Sabry
- Nephrology Department, Mansoura Urology and Nephrology Center, Mansoura University, Mansoura, Egypt.
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Sabry AA, Elbasyouni SR, Kalil AM, Abdel-Rahim M, Mohsen T, Sleem A. Markers of inflammation and atherosclerosis in Egyptian patients with systemic lupus erythematosus. Nephrology (Carlton) 2006; 11:329-35. [PMID: 16889573 DOI: 10.1111/j.1440-1797.2006.00573.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cardiovascular events are markedly increased in systemic lupus erythematosus (SLE) and the mechanism of atherogenesis remains poorly understood. Low-grade inflammation and endothelial dysfunction play pivotal roles in the initiation, progression and propagation of the atherosclerotic process. Several methods have been employed to assess endothelial function, among them the measurement of biomarkers of endothelial activation and dysfunction (intercellular adhesion molecule (ICAM)-1). Since then, it has been reported that such biomarkers play a more important role than traditional risk factors in cardiovascular disease. OBJECTIVE To measure (tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and ICAM-1) levels as markers of inflammation and atherosclerosis in 40 Egyptian patients with SLE with various degrees of activity in comparison with 20 healthy volunteers, and to investigate their relationship to disease activity and hypertension. METHODS Sixty subject (40 with SLE and 20 healthy controls) were the subject of this study, their clinical disease activity was scored according to the SLE Disease Activity Index (SLEDAI), and serum sampling was obtained for TNF-alpha, IL-6 and ICAM-1 level assay. Renal biopsy was carried out and examined by light microscopy. The mean level of TNF-alpha, IL-6 and ICAM-1 were significantly higher in SLE patients with active disease (766.95 +/- 357.82 Pg/mL, 135.4 +/- 54.23 Pg/mL, 826.05 +/- 367.1 Pg/mL) when compared with those with inactive disease (314.01 +/- 100.87 Pg/mL, 47.33 +/- 18.61 pg/mL, 441.33 +/- 225.19 Pg/mL) and healthy control volunteers (172.7 +/- 39.19 Pg/mL, 21.15 +/- 10.99 Pg/mL, 111.5 +/- 17.36 Pg/mL), respectively. Furthermore, these levels were significantly higher in hypertensive (614.08 +/- 333.05 Pg/mL, 107.86 +/- 54.96 Pg/mL and 862.13 +/- 333.29 Pg/mL) compared to normotensive patients (267.5 +/- 112.72 Pg/mL, P = 0.008, 35.75 +/- 20.26 Pg/mL, P = 0.02I, and 337.25 +/- 235.62 Pg/mL, P = 0.02) for TNF-alpha, IL-6 and ICAM, respectively. There were no statistically significant difference regarding age, sex, smoking, cholesterol and high-density lipoprotein (HDL) levels between hypertensive and normotensive patients. CONCLUSION A high concentration of soluble ICAM-1 in Egyptian patients with SLE and nephritis is reported here for the first time. Our finding of increased concentrations of TNF-alpha, IL-6 and ICAM-1 in Egyptian patients with SLE and lupus nephritis underlines the importance of inflammation and endothelial involvement in this disorder, but their predictive value in the disease monitoring needs to be further studied.
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Affiliation(s)
- Alaa A Sabry
- Department of Nephrology and Internal Medicine, Mansoura University, Egypt.
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Reikerås O, Shegarfi H, Wang JE, Utvåg SE. Lipopolysaccharide impairs fracture healing: an experimental study in rats. Acta Orthop 2005; 76:749-53. [PMID: 16470425 DOI: 10.1080/17453670510045327] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND It has been shown that trauma causes translocation of lipopolysaccharide (LPS) endotoxins from the gut. LPS has been identified as a major bacterial bone resorbing factor. The effects of LPS on bone healing are therefore of clinical interest, as trauma involving fractures followed by sepsis is a clinical scenario. We investigated the effects of systemic and local administration of LPS on the healing of femoral fractures in rats. ANIMALS AND METHODS In 3 groups, each consisting of 9 rats, a mid-diaphyseal osteotomy/fracture of the femoral bone was performed and then nailed. In one group of animals, LPS was applied intraperitoneally (systemically), and in another group, LPS was applied locally at the fracture site. The third group served as a control. The animals were killed after 6 weeks, and the mechanical characteristics of the healing osteotomies were evaluated. RESULTS We found that LPS induced a hypertrophic and immature callus, as evaluated by bone mineral content and density. In the rats given LPS intraperitoneally, the mechanical strength characteristics were reduced, as evaluated by bending moment, rigidity, and energy absorption. INTERPRETATION The rats given LPS intraperitoneally reflect a clinical situation with fracture trauma and endotoxinemia. Our findings indicate that endotoxinemia may impair the fracture healing processes.
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Affiliation(s)
- Olav Reikerås
- Department of Orthopaedics, Rikshospitalet University Clinic, Norway.
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Sabry AA, Kalil AM, El-Rahim MA, El-Shahat FB, Elbasyouni SR. Proinflammatory Cytokines (TNF alpha and IL-6) in Egyptian SLE Patients With Lupus Nephritis. ELECTRONIC JOURNAL OF GENERAL MEDICINE 2005. [DOI: 10.29333/ejgm/82333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Andrian E, Grenier D, Rouabhia M. Porphyromonas gingivalis lipopolysaccharide induces shedding of syndecan-1 expressed by gingival epithelial cells. J Cell Physiol 2005; 204:178-83. [PMID: 15648090 DOI: 10.1002/jcp.20287] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Syndecans are constitutively shed from growing epithelial cells as the part of normal cell surface turnover. However, increased serum levels of the soluble syndecan ectodomain have been reported to occur during bacterial infections. The aim of this study was to evaluate the potential of lipopolysaccharide (LPS) from the periodontopathogen Porphyromonas gingivalis to induce the shedding of syndecan-1 expressed by human gingival epithelial cells. We showed that the syndecan-1 ectodomain is constitutively shed from the cell surface of human gingival epithelial cells. This constitutive shedding corresponding to the basal level of soluble syndecan-1 ectodomain was significantly increased when cells were stimulated with P. gingivalis LPS and reached a level comparable to that caused by phorbol myristic acid (PMA), an activator of protein kinase C (PKC) which is well known as a shedding agonist. The syndecan-1 shedding was paralleled by pro-inflammatory cytokine interleukin-1 beta (IL-1beta), IL-6, IL-8, and tumor necrosis factor alpha (TNF-alpha) release. Indeed, secretion of IL-1beta and TNF-alpha increased following stimulation by P. gingivalis LPS and PMA, respectively. When recombinant forms of these proteins were added to the cell culture, they induced a concentration-dependent increase in syndecan-1 ectodomain shedding. A treatment with IL-1beta converting enzyme (ICE) specific inhibitor prevented IL-1beta secretion by epithelial cells stimulated by P. gingivalis LPS and decreased the levels of shed syndecan-1 ectodomain. We also observed that PMA and TNF-alpha stimulated matrix metalloproteinase-9 secretion, whereas IL-1beta and P. gingivalis LPS did not. Our results demonstrated that P. gingivalis LPS stimulated syndecan-1 shedding, a phenomenon that may be mediated in part by IL-1beta, leading to an activation of intracellular signaling pathways different from those involved in PMA stimulation.
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Affiliation(s)
- Elisoa Andrian
- Groupe de Recherche en Ecologie Buccale, Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec, Canada
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Park PW, Pier GB, Preston MJ, Goldberger O, Fitzgerald ML, Bernfield M. Syndecan-1 shedding is enhanced by LasA, a secreted virulence factor of Pseudomonas aeruginosa. J Biol Chem 2000; 275:3057-64. [PMID: 10652286 DOI: 10.1074/jbc.275.5.3057] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Microbial pathogens frequently take advantage of host systems for their pathogenesis. Shedding of cell surface molecules as soluble extracellular domains (ectodomains) is one of the host responses activated during tissue injury. In this study, we examined whether pathogenic bacteria can modulate shedding of syndecan-1, the predominant syndecan of host epithelia. Our studies found that overnight culture supernatants of Pseudomonas aeruginosa and Staphylococcus aureus enhanced the shedding of syndecan-1 ectodomains, whereas culture supernatants of several other Gram-negative and Gram-positive bacteria had only low levels of activity. Because supernatants from all tested strains of P. aeruginosa (n = 9) enhanced syndecan-1 shedding by more than 4-fold above control levels, we focused our attention on this Gram-negative bacterium. Culture supernatants of P. aeruginosa increased shedding of syndecan-1 in both a concentration- and time-dependent manner, and augmented shedding by various host cells. A 20-kDa shedding enhancer was partially purified from the supernatant through ammonium sulfate precipitation and gel chromatography, and identified by N-terminal sequencing as LasA, a known P. aeruginosa virulence factor. LasA was subsequently determined to be a syndecan-1 shedding enhancer from the findings that (i) immunodepletion of LasA from the partially purified sample resulted in abrogation of its activity to enhance shedding and (ii) purified LasA increased shedding in a concentration-dependent manner. Our results also indicated that LasA enhances syndecan-1 shedding by activation of the host cell's shedding mechanism and not by direct interaction with syndecan-1 ectodomains. Enhanced syndecan-1 shedding may be a means by which pathogenic bacteria take advantage of a host mechanism to promote their pathogenesis.
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Affiliation(s)
- P W Park
- Division of Newborn Medicine, Department of Medicine, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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