BCG vaccine in Korea.

The anti-tuberculosis Bacille de Calmette et Guérin (BCG) vaccine was developed between 1905 and 1921 at Pasteur Institutes of Lille in France, and was adopted by many countries. BCG strains comprise natural mutants of major virulence factors of Mycobacterium tuberculosis and that BCG sub-strains differ markedly in virulence levels. The tuberculosis became endemic in Korea after the Korean War (1950s). The BCG strain, which was donated by Pasteur Institutes, was brought to Korea in 1955, and the first domestic BCG vaccine was produced by the National Defense Research Institute (NDRI), current Korea Centers for Disease Control and Prevention (KCDC), in 1960. Since 1987, BCG manufacture work was handed over to the Korean Institute of Tuberculosis (KIT), the freeze-dried BCG vaccine was manufactured at a scale required to meet the whole amount of domestic consumption. However, since 2006, the manufacture of BCG vaccine suspended and the whole amount of BCG was imported at this point of time. Now KIT is planning to re-produce the BCG vaccine in Korea under the supervision of KCDC, this will be render great role to National Tuberculosis Control Program (NTP) and provide initiating step for developing new tuberculosis vaccines in Korea.

Complete Genome Sequence of Mycobacterium bovis BCG Korea, the Korean Vaccine Strain for Substantial Production.

Mycobacterium bovis bacillus Calmette-Guérin (BCG) is the only vaccine available against tuberculosis, and the strains used worldwide represent a family of daughter strains with distinct genotypic characteristics. Here, we report the complete genome sequence of M. bovis BCG Korea, the strain that will be actually used in Korea for vaccine production.

Suppression of Toll-like receptor 4 activation by endogenous oxidized phosphatidylcholine, KOdiA-PC by inhibiting LPS binding to MD2.

OBJECTIVE: Activation of Toll-like receptor 4 (TLR4) triggers immune and inflammatory events by sensing endogenous danger signals as well as invading pathogens and contributes to the development of chronic inflammatory diseases. In this study, we investigated effect of 1-palmitoyl-2-(5-keto-6-octenedioyl)-sn-glycero-3-phosphocholine (KOdiA-PC), an oxidized phosphatidylcholine, on TLR4 activation and the underlying regulatory mechanism. METHODS: RAW264.7 macrophages were used for the study. The levels of TNF-α, IFN-ß, and COX-2 mRNA and protein were determined by quantitative PCR and ELISA, respectively. Activation of TLR4-signaling was examined by immunoblot and luciferase reporter assays. In vitro binding assay was performed to determine LPS binding to MD2. Macrophage migration was analyzed using a transwell-culture system. RESULTS: KOdiA-PC prevented the activation of TLR4-signaling components including ERK, JNK, p38, NF-κB, and IRF3 leading to decrease of TNF-α, IFN-ß, and COX-2 expression. In vitro binding assay revealed that KOdiA-PC interrupted LPS binding to MD2, a TLR4 co-receptor. Consistently, KOdiA-PC suppressed LPS-induced macrophage migration. CONCLUSION: The results demonstrate that KOdiA-PC can modulate TLR4 activation by regulating ligand-receptor interaction. Therefore, endogenously generated, oxidized phospholipids may play a role in resolving inflammation by terminating TLR activation and macrophage recruitment to the inflamed site.

PI3K/Akt contributes to increased expression of Toll-like receptor 4 in macrophages exposed to hypoxic stress.

Toll-like receptors (TLRs) play critical roles in triggering immune and inflammatory responses by detecting invading microbial pathogens and endogenous danger signals. Increased expression of TLR4 is implicated in aggravated inflammatory symptoms in ischemic tissue injury and chronic diseases. Results from our previous study showed that TLR4 expression was upregulated by hypoxic stress mediated by hypoxia-inducible factor-1 (HIF-1) at a transcriptional level in macrophages. In this study, we further investigated the upstream signaling pathway that contributed to the increase of TLR4 expression by hypoxic stress. Either treatment with pharmacological inhibitors of PI3K and Akt or knockdown of Akt expression by siRNA blocked the increase of TLR4 mRNA and protein levels in macrophages exposed to hypoxia and CoCl(2). Phosphorylation of Akt by hypoxic stress preceded nuclear accumulation of HIF-1α. A PI3K inhibitor (LY294002) attenuated CoCl(2)-induced nuclear accumulation and transcriptional activation of HIF-1α. In addition, HIF-1α-mediated upregulation of TLR4 expression was blocked by LY294002. Furthermore, sulforaphane suppressed hypoxia- and CoCl(2)-induced upregulation of TLR4 mRNA and protein by inhibiting PI3K/Akt activation and the subsequent nuclear accumulation and transcriptional activation of HIF-1α. However, p38 was not involved in HIF-1α activation and TLR4 expression induced by hypoxic stress in macrophages. Collectively, our results demonstrate that PI3K/Akt contributes to hypoxic stress-induced TLR4 expression at least partly through the regulation of HIF-1 activation. These reveal a novel mechanism for regulation of TLR4 expression upon hypoxic stress and provide a therapeutic target for chronic diseases related to hypoxic stress.

Akt contributes to activation of the TRIF-dependent signaling pathways of TLRs by interacting with TANK-binding kinase 1.

Toll/IL-1R domain-containing adaptor inducing IFN-ß (TRIF) is an adaptor molecule that is recruited to TLR3 and -4 upon agonist stimulation and triggers activation of IFN regulatory factor 3 (IRF3) and expression of type 1 IFNs, which are critical for cellular antiviral responses. We show that Akt is a downstream molecule of TRIF/TANK-binding kinase 1 (TBK1) and plays an important role in the activation of IRF3 by TLR3 and -4 agonists. Blockade of Akt by a dominant-negative mutant or by short interfering RNA decreased IRF3 activation and IFN-ß expression induced by polyinosinic:polycytidylic acid [poly(I:C)], LPS, TRIF, and TBK1. Association of endogenous TBK1 and Akt was observed in macrophages when stimulated with poly(I:C) and LPS. In vitro kinase assays combined with reversed-phase liquid chromatography mass spectrometry analysis showed that TBK1 enhanced phosphorylation of Akt on Ser(473), whereas knockdown of TBK1 expression by short interfering RNA in macrophages decreased poly(I:C)- and LPS-induced Akt phosphorylation. Embryonic fibroblasts derived from TBK1 knockout mice also showed impaired Akt phosphorylation in response to poly(I:C) and LPS. To our knowledge, our results demonstrate a new regulatory mechanism for Akt activation mediated by TBK1 and a novel role of Akt in TLR-mediated immune responses.

Sulforaphane suppresses oligomerization of TLR4 in a thiol-dependent manner.

TLRs are pattern recognition receptors that detect invading microorganisms and nonmicrobial endogenous molecules to trigger immune and inflammatory responses during host defense and tissue repair. TLR activity is closely linked to the risk of many inflammatory diseases and immune disorders. Therefore, TLR signaling pathways can provide efficient therapeutic targets for chronic diseases. Sulforaphane (SFN), an isothiocyanate, has been well known for its anti-inflammatory activities. In this study, we investigated the modulation of TLR activity by SFN and the underlying mechanism. SFN suppressed ligand-induced and ligand-independent TLR4 activation because it prevented IL-1R-associated kinase-1 degradation, activation of NF-kappaB and IFN regulatory factor 3, and cyclooxygenase-2 expression induced by LPS or overexpression of TLR4. Receptor oligomerization, which is one of the initial and critical events of TLR4 activation, was suppressed by SFN, resulting in the downregulation of NF-kappaB activation. SFN formed adducts with cysteine residues in the extracellular domain of TLR4 as confirmed by liquid chromatography-tandem mass spectrometry analysis and the inhibitory effects of SFN on oligomerization and NF-kappaB activation were reversed by thiol donors (DTT and N-acetyl-L-cysteine). These suggest that the reactivity of SFN to sulfhydryl moiety contributes to its inhibitory activities. Blockade of TLR4 signaling by SFN resulted in the reduced production of inflammatory cytokines and the decreased dermal inflammation and edema in vivo in experimental inflammatory animal models. Collectively, our results demonstrated that SFN downregulated TLR4 signaling through the suppression of oligomerization process in a thiol-dependent manner. These present a novel mechanism for beneficial effects of SFN and a novel anti-inflammatory target in TLR4 signaling.

Hypoxic stress up-regulates the expression of Toll-like receptor 4 in macrophages via hypoxia-inducible factor.

Toll-like receptors (TLRs) are germline-encoded innate immune receptors that recognize invading micro-organisms and induce immune and inflammatory responses. Deregulation of TLRs is known to be closely linked to various immune disorders and inflammatory diseases. Cells at sites of inflammation are exposed to hypoxic stress, which further aggravates inflammatory processes. We have examined if hypoxic stress modulates the TLR activity of macrophages. Hypoxia and CoCl(2) (a hypoxia mimetic) enhanced the expression of TLR4 messenger RNA and protein in macrophages (RAW264.7 cells), whereas the messenger RNA of other TLRs was not increased. To determine the underlying mechanism, we investigated the role of hypoxia-inducible factor 1 (HIF-1) in the regulation of TLR4 expression. Knockdown of HIF-1alpha expression by small interfering RNA inhibited hypoxia-induced and CoCl(2)-induced TLR4 expression in macrophages, while over-expression of HIF-1alpha potentiated TLR4 expression. Chromatin immunoprecipitation assays revealed that HIF-1alpha binds to the TLR4 promoter region under hypoxic conditions. In addition, deletion or mutation of a putative HIF-1-binding motif in the TLR4 promoter greatly attenuated HIF-1alpha-induced TLR4 promoter reporter expression. Up-regulation of TLR4 expression by hypoxic stress enhanced the response of macrophages to lipopolysaccharide, resulting in increased expression of cyclooxygenase-2, interleukin-6, regulated on activation normal T cell expressed and secreted, and interferon-inducible protein-10. These results demonstrate that TLR4 expression in macrophages is up-regulated via HIF-1 in response to hypoxic stress, suggesting that hypoxic stress at sites of inflammation enhances susceptibility to subsequent infection and inflammatory signals by up-regulating TLR4.