Reactive oxygen species and p47phox activation are essential for the Mycobacterium tuberculosis-induced pro-inflammatory response in murine microglia

Yang Chul-Su, Lee Hye-Mi, Lee Ji-Yeon, Kim Jeong-Ah, Lee, Shin Dong-Min, Lee Young-Ho, Lee Dong-Seok, El-Benna Jamel, Jo, Jo Eun-Kyeong

Description

Activated microglia elicits a robust amount of pro-inflammatory cytokines, which are implicated in the pathogenesis of tuberculosis in the central nervous system (CNS). However, little is known about the intracellular signaling mechanisms governing these inflammatory responses in microglia in response to Mycobacterium tuberculosis (Mtb). Methods Murine microglial BV-2 cells and primary mixed glial cells were stimulated with sonicated Mtb (s-Mtb). Intracellular ROS levels were measured by staining with oxidative fluorescent dyes [2',7'-Dichlorodihydrofluorescein diacetate (H 2 DCFDA) and dihydroethidium (DHE)]. NADPH oxidase activities were measured by lucigenin chemiluminescence assay. S-Mtb-induced MAPK activation and pro-inflammatory cytokine release in microglial cells were measured using by Western blot analysis and enzyme-linked immunosorbent assay, respectively. Results We demonstrate that s-Mtb promotes the up-regulation of reactive oxygen species (ROS) and the rapid activation of mitogen-activated protein kinases (MAPKs), including p38 and extracellular signal-regulated kinase (ERK) 1/2, as well as the secretion of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-12p40 in murine microglial BV-2 cells and primary mixed glial cells. Both NADPH oxidase and mitochondrial electron transfer chain subunit I play an indispensable role in s-Mtb-induced MAPK activation and pro-inflammatory cytokine production in BV-2 cells and mixed glial cells. Furthermore, the activation of cytosolic NADPH oxidase p47phox and MAPKs (p38 and ERK1/2) is mutually dependent on s-Mtb-induced inflammatory signaling in murine microglia. Neither TLR2 nor dectin-1 was involved in s-Mtb-induced inflammatory responses in murine microglia. Conclusion These data collectively demonstrate that s-Mtb actively induces the pro-inflammatory response in microglia through NADPH oxidase-dependent ROS generation, although the specific pattern-recognition receptors involved in these responses remain to be identified.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2007
• Nombre de lectures: 4
• Langue: English

Extrait

Journal of Neuroinflammation

BioMedCentral

Open Access Research Reactive oxygen species and p47phox activation are essential for theMycobacterium tuberculosisinduced proinflammatory response in murine microglia †1 †1†1 2 ChulSu Yang, HyeMi Lee, JiYeon Lee, JeongAh Kim, Sung 3 12 4 Joong Lee, DongMin Shin, YoungHo Lee, DongSeok Lee, Jamel 5 1,6 ElBenna andEunKyeong Jo*

1 2 Address: Departmentof Microbiology, College of Medicine, Chungnam National University, Daejeon 301747, S. Korea,Department of 3 Anatomy, College of Medicine, Chungnam National University, Daejeon 301747, S. Korea,Department of Oral Physiology, School of Dentistry, 4 Seoul National University, 28 Yeongundong, Jongnogu, Seoul 110749, S. Korea,College of animal resource sciences, Kangwon National 5 6 University, Chunchon 200701, Korea,Inserm U773, Université Paris 7Denis Diderot, Site Bichat, Paris, France andInfection Signaling Network Research Center, College of Medicine, Chungnam National University, Daejeon 301747, S. Korea

Email: ChulSu Yang  [e-mail]; HyeMi Lee  [e-mail]; JiYeon Lee  [e-mail]; Jeong Ah Kim  [e-mail]; Sung Joong Lee  [e-mail]; DongMin Shin  [e-mail]; Young Ho Lee  [e-mail]; DongSeok Lee  [e-mail]; Jamel ElBenna  [e-mail]; Eun Kyeong Jo*  [e-mail] * Corresponding author†Equal contributors

Published: 26 November 2007Received: 28 August 2007 Accepted: 26 November 2007 Journal of Neuroinflammation2007,4:27 doi:10.1186/17422094427 This article is available from: http://www.jneuroinflammation.com/content/4/1/27 © 2007 Yang et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:Activated microglia elicits a robust amount of proinflammatory cytokines, which are implicated in the pathogenesis of tuberculosis in the central nervous system (CNS). However, little is known about the intracellular signaling mechanisms governing these inflammatory responses in microglia in response toMycobacterium tuberculosis(Mtb). Methods:Murine microglial BV2 cells and primary mixed glial cells were stimulated with sonicated Mtb (sMtb). Intracellular ROS levels were measured by staining with oxidative fluorescent dyes [2',7'Dichlorodihydrofluorescein diacetate (H DCFDA) 2 and dihydroethidium (DHE)]. NADPH oxidase activities were measured by lucigenin chemiluminescence assay. SMtbinduced MAPK activation and proinflammatory cytokine release in microglial cells were measured using by Western blot analysis and enzymelinked immunosorbent assay, respectively. Results:We demonstrate that sMtb promotes the upregulation of reactive oxygen species (ROS) and the rapid activation of mitogenactivated protein kinases (MAPKs), including p38 and extracellular signalregulated kinase (ERK) 1/2, as well as the secretion of tumor necrosis factor (TNF)α, interleukin (IL)6, and IL12p40 in murine microglial BV2 cells and primary mixed glial cells. Both NADPH oxidase and mitochondrial electron transfer chain subunit I play an indispensable role in sMtbinduced MAPK activation and proinflammatory cytokine production in BV2 cells and mixed glial cells. Furthermore, the activation of cytosolic NADPH oxidase p47phox and MAPKs (p38 and ERK1/2) is mutually dependent on sMtbinduced inflammatory signaling in murine microglia. Neither TLR2 nor dectin1 was involved in sMtbinduced inflammatory responses in murine microglia. Conclusion:These data collectively demonstrate that sMtb actively induces the proinflammatory response in microglia through NADPH oxidasedependent ROS generation, although the specific patternrecognition receptors involved in these responses remain to be identified.

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