-
[show abstract]
[hide abstract]
ABSTRACT: Two closely related bacterial species, Segniliparus rotundus and Segniliparus rugosus, have emerged as important human pathogens, but little is known about the immune responses they elicit or their comparative pathophysiologies. To determine the virulence and immune responses of the two species, we compared their abilities to grow in phagocytic and non-phagocytic cells. Both species maintained non-replicating states within A549 epithelial cells. S. rugosus persisted longer and multiplied more rapidly inside murine bone marrow-derived macrophages (BMDMs), induced more pro-inflammatory cytokines, and induced higher levels of macrophage necrosis. Activation of BMDMs by both species was mediated by toll-like receptor 2 (TLR2), followed by mitogen-activated protein kinases (MAPK) and nuclear factor κB (NF-κB) signaling pathways, indicating a critical role for TLR2 in Segniliparus-induced macrophage activation. S. rugosus triggered faster and stronger activation of MAPK signaling and IκB degradation, indicating that S. rugosus induces more pro-inflammatory cytokines than S. rotundus. Multifocal granulomatous inflammations in the liver and lung were observed in mice infected with S. rugosus, but S. rotundus was rapidly cleared from all organs tested within 15 days post-infection. Furthermore, S. rugosus induced faster infiltration of innate immune cells such as neutrophils and macrophages to the lung than S. rotundus. Our results suggest that S. rugosus is more virulent and induces a stronger immune response than S. rotundus.
PLoS ONE 01/2013; 8(3):e59646. · 4.09 Impact Factor
-
Eui-Hong Byun,
Woo Sik Kim,
Jong-Seok Kim, Choul-Jae Won,
Han-Gyu Choi,
Hwa-Jung Kim,
Sang-Nae Cho,
Keehoon Lee,
Tiejun Zhang,
Gang Min Hur,
Sung Jae Shin
[show abstract]
[hide abstract]
ABSTRACT: Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of Johne's disease in animals and MAP involvement in human Crohn's disease has been recently emphasized. Evidence from M. tuberculosis studies suggests mycobacterial proteins activate dendritic cells (DCs) via Toll-like receptor (TLR) 4, eventually determining the fate of immune responses. Here, we investigated whether MAP CobT contributes to the development of T cell immunity through the activation of DCs. MAP CobT recognizes TLR4, induces DC maturation and activation via the MyD88 and TRIF signaling cascades, which are followed by MAP kinases and NF-κB. We further found that MAP CobT-treated DCs activated naive T cells, effectively polarized CD4+ and CD8+ T cells to secrete IFN-γ and IL-2, but not IL-4 and IL-10, and induced T cell proliferation. These data indicate MAP CobT contributes to T helper (Th) 1-polarization of the immune response. MAP CobT-treated DCs specifically induced the expansion of CD4+/CD8+CD44highCD62Llow memory T cells in the mesenteric lymph node (MLN) of MAP-infected mice in a TLR4-dependent manner. Our results indicate that MAP CobT is a novel DC maturation-inducing antigen that drives Th1 polarized-naive/memory T cell expansion in a TLR4-dependent cascade, suggesting that MAP CobT potentially links innate and adaptive immunity against MAP.
Journal of Biological Chemistry 09/2012; · 4.77 Impact Factor
-
Go-Eun Choi,
Sung Jae Shin, Choul-Jae Won,
Ki-Nam Min,
Taegwon Oh,
Mi-Young Hahn,
Keehoon Lee,
Soo Hyun Lee,
Charles L Daley,
Seonwoo Kim,
Byeong-Ho Jeong,
Kyeongman Jeon,
Won-Jung Koh
[show abstract]
[hide abstract]
ABSTRACT: RATIONALE: Macrolides, such as clarithromycin (CLR) and azithromycin (AZM), are frequently the only oral antibiotics that are active against Mycobacterium abscessus and Mycobacterium massiliense infections. Neither CLR nor AZM have previously been demonstrated to provide superior treatment efficacy for these infections. OBJECTIVES: We compared the treatment efficacies of CLR and AZM and determined the correlation between efficacy and induced erm(41) expression in experimental models of M. abscessus and M. massiliense infections. MEASUREMENTS AND MAIN RESULTS: In all tested M. abscessus isolates, a high level of inducible CLR resistance developed (minimal inhibitory concentration [MIC] on day 3 vs. day 14; P<0.001). Whereas the AZM MIC increased on day 14 (P<0.01 vs. day 3), the level was significantly lower than the CLR MIC on day 14 (P<0.001). However, the MICs of CLR and AZM for the M. massiliense isolates did not change. Compared to CLR, AZM presented greater antibiotic activity against M. abscessus in vitro, ex vivo, and in vivo (P<0.05), whereas both macrolides were comparably effective against M. massiliense. In M. abscessus infection, the level of erm(41) expression was higher following exposure to CLR than following exposure to AZM (P<0.001). Experiments using an erm(41)-knockout M. abscessus mutant and an M. massiliense transformant expressing M. abscessus erm(41) confirmed that erm(41) was responsible for inducible CLR resistance. CONCLUSIONS: CLR induces greater erm(41) expression and thus higher macrolide resistance than AZM in M. abscessus infection. AZM may be more effective against M. abscessus, whereas both macrolides appear to be equally effective against M. massiliense.
American Journal of Respiratory and Critical Care Medicine 08/2012; · 11.08 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Infections caused by Mycobacterium abscessus and Mycobacterium massiliense are on the rise among humans. Although macrolides, including clarithromycin (CLR) and azithromycin (AZM), are key antibiotics for the treatment of M. abscessus and M. massiliense infections, treatment regimens for these infections are still largely undefined. In this study, we evaluated the in vitro, ex vivo, and in vivo activities of moxifloxacin (MXF) in combination with macrolides against clinically isolated M. abscessus and M. massiliense strains. Overall, CLR, AZM, and MXF alone showed activity against both species in vitro, ex vivo, and in vivo. When MXF was combined with a macrolide against M. abscessus isolates, antagonism was observed in 65.4% (17/26) of the strains with CLR and 46.2% (12/26) of the strains with AZM in vitro as well as in 66.7% (10/15) of the strains with CLR and 40.0% (6/15) of the strains with AZM in macrophages as determined by the fractional inhibitory concentration index. In contrast, either indifferent or synergistic effects of the MXF-macrolide combinations were observed against only M. massiliense strains. Moreover, a murine infection model showed similar results. Antagonism between the MXF and macrolide combinations was observed in five out of seven M. abscessus strains, while indifferent and synergistic effects for these combinations were observed for three of the six M. massiliense strains tested, respectively. In conclusion, the activity of MXF in combination with a macrolide differed for M. abscessus and M. massiliense infections and the addition of MXF to macrolide therapy had no benefit for the treatment of M. abscessus infections.
Antimicrobial Agents and Chemotherapy 05/2012; 56(7):3549-55. · 4.84 Impact Factor
-
Eui-Hong Byun,
Woo Sik Kim,
A-Rum Shin,
Jong-Seok Kim,
Jake Whang, Choul-Jae Won,
Yohan Choi,
Su-Young Kim,
Won Jung Koh,
Hwa-Jung Kim,
Sung Jae Shin
[show abstract]
[hide abstract]
ABSTRACT: Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) is one of the most deadly infectious diseases, with approximately two million people dying of TB annually. An effective therapeutic method for activating dendritic cells (DCs) and driving Th1 immune responses would improve host defenses and further the development of a TB vaccine. Given the importance of DC maturation in eliciting protective immunity against TB, we investigated whether Rv0315, a newly identified Mtb antigen, can prompt DC maturation. We found that Rv0315 functionally activated DCs by augmenting the expression of the co-stimulatory molecules CD80 and CD86 as well as MHC class I/II molecules. Moreover, it increased DC secretion of the pro-inflammatory cytokines IL-6, IL-1β, and TNF-α. Unlike LPS, however, Rv0315 induced the secretion of IL-12p70, but not IL-10. In addition, Rv0315-treated DCs accelerated the proliferation of CD4(+) and CD8(+) splenic T cells from Mtb-infected mice, with increased levels of IFN-γ, in syngeneic and allogeneic mixed lymphocyte reactions, indicating that Rv0315 contributes to Th1 polarization of the immune response. Importantly, both mitogen-activated protein kinases and nuclear factor κB signaling mediated the expression of DC surface markers and cytokines. Taken together, our results indicate that Rv0315 is a novel DC maturation-inducing antigen that drives T cell immune responses toward Th1 polarization, suggesting that Rv0315 plays a key role in determining the nature of the immune response to TB.
Journal of Molecular Medicine 03/2012; 90(3):285-98. · 4.67 Impact Factor
-
Hosung Sohn,
Jong-Seok Kim,
Sung Jae Shin,
Kwangwook Kim, Choul-Jae Won,
Woo Sik Kim,
Ki-Nam Min,
Han-Gyu Choi,
Je Chul Lee,
Jeong-Kyu Park,
Hwa-Jung Kim
[show abstract]
[hide abstract]
ABSTRACT: Mycobacterium tuberculosis heparin-binding hemagglutinin (HBHA), a virulence factor involved in extrapulmonary dissemination and a strong diagnostic antigen against tuberculosis, is both surface-associated and secreted. The role of HBHA in macrophages during M. tuberculosis infection, however, is less well known. Here, we show that recombinant HBHA produced by Mycobacterium smegmatis effectively induces apoptosis in murine macrophages. DNA fragmentation, nuclear condensation, caspase activation, and poly (ADP-ribose) polymerase cleavage were observed in apoptotic macrophages treated with HBHA. Enhanced reactive oxygen species (ROS) production and Bax activation were essential for HBHA-induced apoptosis, as evidenced by a restoration of the viability of macrophages pretreated with N-acetylcysteine, a potent ROS scavenger, or transfected with Bax siRNA. HBHA is targeted to the mitochondrial compartment of HBHA-treated and M. tuberculosis-infected macrophages. Dissipation of the mitochondrial transmembrane potential (ΔΨ(m)) and depletion of cytochrome c also occurred in both macrophages and isolated mitochondria treated with HBHA. Disruption of HBHA gene led to the restoration of ΔΨ(m) impairment in infected macrophages, resulting in reduced apoptosis. Taken together, our data suggest that HBHA may act as a strong pathogenic factor to cause apoptosis of professional phagocytes infected with M. tuberculosis.
PLoS Pathogens 12/2011; 7(12):e1002435. · 9.13 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Mycobacterium massiliense is an emerging pathogen and very similar to Mycobacterium abscessus of rapidly growing mycobacteria in the phenotype and genotype. Pathogenic bacteria secrete a diversity of factors into extracellular medium which contribute to the bacterial pathogenicity. In the present study, we performed the comparative proteome analysis of culture filtrate proteins from a clinical isolate of M. massiliense and M. abscessus strains using two-dimensional gel electrophoresis and liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS). Interestingly, 9 proteins of M. massiliense were distinctly expressed from those of M. abscessus. Bioinformatic analysis of the identified proteins revealed that 3 unique proteins corresponded to serine/arginine rich protein, membrane protein from Streptomyces coelicolor, and one hypothetical protein from Corynebacterium efficiens YS-314, respectively. Culture filtrate proteins from M. massiliense induced the release of pro-inflammatory cytokines from macrophages in a dose-dependent manner but not that from M. abscessus. Taken together, the functional study on the identified proteins uniquely produced from M. massiliense may provide not only the clues for the different pathogensis, but also help develop the diagnostic tools for the differentiation between two mycobacterial species.
The Journal of Microbiology 08/2010; 48(4):502-11. · 1.10 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Mycobacterium kansasii is a facultative intracellular pathogen causing pulmonary disease in immunocompetent patients. Little is known about the host defense against M. kansasii and its intracellular survival strategy inside macrophages. In the present study, we obtained six clinical isolates from patients with M. kansasii pulmonary disease and investigated the intracellular growth and cytotoxic effects of M. kansasii inside mouse bone marrow-derived macrophages (BMDM) as well as cytokine secretion from BMDM. Interestingly, two isolates, SM-1 and 2693-20, displayed faster growth rates and higher levels of TNF-alpha secretion from macrophages when compared to the other strains. In addition, SM-1 and 2693-20 also induced massive cell death in BMDM and THP-1 acute monocytic leukemia cells, while the slow growing strains induced significantly lower levels of cell death. This cytotoxicity was mainly caused by necrosis, not apoptosis and it was TNF-alpha-independent. Caspase inhibitors failed to block M. kansasii-induced macrophage death. In addition, necrosis caused by the fast growing strains was accompanied by the loss of mitochondrial membrane potential (DeltaPsi(m)). When dissipation of DeltaPsi(m) was inhibited by the classical mitochondrial permeability transition (MPT) inhibitor cyclosporine A (CsA), macrophage necrosis was reduced. These results suggest that clinical isolates of M. kansasii that grow faster in macrophages induce higher levels of necrosis in a DeltaPsi(m) loss-dependent manner.
Microbial Pathogenesis 03/2010; 48(5):160-7. · 1.94 Impact Factor
-
Yu-Mi Kwon,
Ki-Hwan Jung,
Go-Eun Choi,
A-Rum Shin,
Byung-Su Lee, Choul-Jae Won,
Woo-Sik Kim,
Sung-Jae Shin,
Jeong-Kyu Park,
Chulhun L Chang,
Hwa-Jung Kim
[show abstract]
[hide abstract]
ABSTRACT: It is important to identify and to test serologically active antigens, so as to devise a cocktail of the best antigens or peptides. We searched for antigens that have serodiagnostic utility using two-dimensional fractionation of sonic extracts from Mycobacterium tuberculosis and probing with pools of sera from healthy subjects and patients with tuberculosis (TB). Reactive protein spots with patient sera were identified by tandem mass spectrometry. Three proteins, Rv0652, Rv2626c, and Rv3418c, which have not previously been described as serologic targets, were identified. Rv0652 protein among them was expressed in Escherichia coli and serum IgG antibodies against this antigen were measured in 150 patients with pulmonary TB and in 115 healthy subjects. The sensitivity and specificity were 39% and 92%, respectively. These results suggest that a newly identified protein, Rv0652 may be a valuable candidate to be included in a cocktail test kit for TB diagnosis.
Journal of Bacteriology and Virology 01/2009; 39:329-336.
