Protective immunity to Mycobacterium tuberculosis infection by chemokine and cytokine conditioned CFP-10 differentiated dendritic cells

Background

Dendritic cells (DCs) play major roles in mediating immune responses to mycobacteria. A crucial aspect of this is the priming of T cells via chemokines and cytokines. In this study we investigated the roles of chemokines RANTES and IP-10 in regulating protective responses from Mycobacterium tuberculosis (M. tb) 10 kDa Culture Filtrate Protein-10 (CFP-10) differentiated DCs (CFP10-DCs).

Methods and Findings

Infection of CFP10-DCs with mycobacteria down-modulated RANTES and IP-10 levels. Pathway specific microarray analyses showed that in addition to RANTES and IP-10, mycobacteria infected CFP10-DCs showed reduced expression of many Th1 promoting chemokines and chemokine receptors. Importantly, T cells co-cultured with RANTES and IP-10 conditioned CFP10-DCs mediated killing of mycobacteria from infected macrophages. Similarly, T cells recruited by RANTES and IP-10 conditioned CFP10-DCs mediated significant killing of mycobacteria from infected macrophages. IFN-gamma treatment of CFP10-DCs restored RANTES and IP-10 levels and T cells activated by these DCs mediated significant killing of virulent M. tb inside macrophages. Adoptive transfer of either RANTES and IP-10 or IL-12 and IFN-gamma conditioned CFP10-DCs cleared an established M. tb infection in mice. The extent of clearance was similar to that obtained with drug treatment.

Conclusions

These results indicate that chemokine and cytokine secretion by DCs differentiated by M. tb antigens such as CFP-10 play major roles in regulating protective immune responses at sites of infection.     

The stimulatory effects of alpha1-adrenergic receptors on TGF-beta1, IGF-1 and hyaluronan production in human skin fibroblasts

Skin fibroblasts modulate tissue repair, wound healing and immunological responses. Adrenergic receptors (ARs) mediate important physiological functions, such as endocrine, metabolic and neuronal activity. In this study, the expression α1A-ARs in human skin fibroblasts is examined and verified. Regulatory effects of α1-agonist cirazoline on cell migration and the production of transforming growth factor β1 (TGF-β1), insulin-like growth factor 1 (IGF-1), hyaluronan (HA), fibronectin and procollagen type I carboxy-terminal peptide (PIP) by human skin fibroblasts are assessed and validated. α1A-AR mRNA and protein were found in human skin fibroblasts WS1. Exposure of cirazoline doubled skin fibroblast migration and the increase in cell migration was attenuated by α1-antagonist prazosin. TGF-β1 mRNA and production were enhanced after exposure to cirazoline and IGF-1 production was also increased after treatment with cirazoline. Exposure to cirazoline also enhanced HA and PIP production. The increases in TGF-β1, IGF-1, HA and PIP production were partially abolished in fibroblasts transfected with α1A-AR short interfering RNAs, indicating that α1A-ARs are involved in the cirazoline-induced increases in TGF-β1, IGF-1, HA and PIP production. Thus, α1A-ARs are stably expressed and stimulate cell migration and TGF-β1, IGF-1, HA and PIP production in human skin fibroblasts. Moreover, TGF-β1, IGF-1, HA and PIP production and the cell migration of human skin fibroblasts are possibly modulated by natural catecholamines produced by the endocrine system or sympathetic innervation, which could directly or indirectly participate in cytokine secretion, fibroblast migration and matrix production of wound healing in the skin.     

Matrilin-3 as a putative effector of C-type natriuretic peptide signaling during TGF-β induced chondrogenic differentiation of mesenchymal stem cells

C-type natriuretic peptide (CNP) signaling has been implicated as an important regulator of chondrogenic differentiation during endochondral bone development. This preliminary study further investigated the putative effectors and/or targets of CNP signaling in transforming growth factor (TGF)-β induced in vitro chondrogenic differentiation of mesenchymal stem cells (MSCs). Previously characterized human trabecular bone derived MSCs were induced either with only TGF-β1 or with a combination of TGF-β1 and CNP in micromass culture for 10 or 20 days. Genome wide gene expression profile changes in between these two groups were analyzed on day-10 or day-20 of culture. Results revealed that there were only 7 genes, whose expression change was fourfolds or higher in TGF-β1 and CNP fed group in comparison to only TGF-β1 fed group. The up-regulated genes included matrilin-3 (MATN3), engulfment and cell motility 1 (ELMO1), CD24, and DCN1, defective in cullin neddylation 1, domain containing 1 (DCUN1D1). The down-regulated genes, on the other hand, included LIM domain kinase 2 (LIMK2), Ewing sarcoma breakpoint region 1, and guanine nucleotide binding protein (G protein), gamma 12 (GNG12). The up-regulation of MATN3 was confirmed on the basis of RT-PCR. The known literature on both CNP signaling and MATN3 function in chondrogenesis match with each other and suggest MATN3 as a putative effector and/or target of CNP signaling during this process.     

Expression and Mechanism of BRP-39 in Bleomycin-Induced Pulmonary Fibrosis in Rat

The purpose of the study was to explore the effects of breast regression protein 39 (BRP-39) in bleomycin-induced pulmonary fibrosis and its mechanism in pulmonary fibrosis by studying change in BRP-39 to provide a novel direction for the treatment of idiopathic pulmonary fibrosis. SPF grade male C57BL/6 rats were randomly divided into three groups, including bleomycin group, bleomycin+ BRP-39 recombinant protein group and control group. HE and Masson staining were applied to test the change in lung tissue after being treated by BRP-39, ELISA was applied to test the expression of TGF-β1 in different groups, and Western blot was used to test the expression of BRP-39 in rat lung tissue. Expression of BRP-39 increased, the fibrosis was obvious, and lung tissue collagen increased in bleomycin-induced pulmonary fibrosis in rat lung tissue. Increasing BRP-39 protein level and intratracheal bleomycin medication to establish pulmonary fibrosis model can aggravate pulmonary fibrosis. Along with the increase in BRP-39 protein level, TGF-β1 expression level also increased in lung tissue. Western blot results showed the expression of BRP-39, and TGF-β1 had the same trend in different groups. BRP-39 has effects in bleomycin-induced rat pulmonary fibrosis. Change in BRP-39 can affect the process of bleomycin-induced pulmonary fibrosis. The mechanism of BRP-3 in pulmonary fibrosis may work by regulating TGF-β1.     

The regulatory peptide apelin: a novel inhibitor of renal interstitial fibrosis

Epithelial–mesenchymal transition (EMT) of tubular epithelial cells is a key event in renal interstitial fibrosis and the progression of chronic kidney disease (CKD). Apelin is a regulatory peptide involved in the regulation of normal renal hemodynamics and tubular functions, but its role in renal fibrosis remains unknown. In this study, we examined the inhibitory effects of apelin on transforming growth factor-β1 (TGF-β1)-induced EMT in HK-2 cells, and evaluated its therapeutic efficacy in mice with complete unilateral ureteral obstruction (UUO). In vitro, apelin inhibited TGF-β1-mediated upregulation of α-smooth muscle actin (α-SMA) and downregulation of E-cadherin. Increased levels of phosphorylated Smad-2/3 and decreased levels of Smad7 in TGF-β1-stimulated cells were reversed by apelin co-treatment. In the UUO model, administration of apelin significantly attenuated renal interstitial fibrosis, as evidenced by the maintenance of E-cadherin and laminin expression, and markedly suppressed expression of α-SMA, TGF-β1 and its type I receptor, as well as interstitial matrix components. Interestingly, in UUO mice, there was a reduction in the plasma level of apelin, which was compensated by upregulation of APJ expression in the injured kidney. Exogenous supplementation of apelin normalized the level of plasmatic apelin and renal APJ. In conclusion, our study provides the first evidence that apelin is able to ameliorate renal interstitial fibrosis by suppression of tubular EMT through a Smad-dependent mechanism. The apelinergic system itself may promote some compensatory response in the renal fibrotic process. These results suggest that apelin has potential renoprotective effects and may be an effective agent for retarding CKD progression.     

Relative mRNA expression and immunolocalization for transforming growth factor-beta (TGF-β) and their effect on in vitro development of caprine preantral follicles

This study aimed to evaluate the immunolocalization and messenger RNA (mRNA) expression for transforming growth factor-beta (TGF-β) and its receptors (TGF-βRI and RII), as well as mRNA expression for P450 aromatase and FSH receptor in caprine preantral follicles. The effects of TGF-β, FSH alone, or in association on the in vitro follicular development were also assessed. Immunohistochemical analyses showed the expression of TGF-β and its receptors in oocytes of all follicle stages and granulosa cells of primary and secondary follicles. mRNA for TGF-β receptors and for FSH receptor (FSHR) was present in preantral follicles as well as in oocytes and granulosa cells of antral follicles. Isolated secondary follicles were cultured in α-minimum essential medium (MEM) alone or supplemented with either FSH (100 ng/ml), TGF-β (10 ng/ml), or TGF-β + FSH for 18 d. TGF-β increased significantly oocyte diameter when compared to FSH alone and control. After 18 d of culture, all groups showed a significant reduction in P450 aromatase and FSHR mRNA levels in comparison to fresh control. In contrast, treatment with FSH significantly increased the mRNA expression for TGF-β in comparison to fresh control and other treatments. In conclusion, the findings showed that TGF-β and its receptors are present in caprine ovarian follicles. Furthermore, they showed a positive effect on oocyte growth in vitro.     

Ancient and diverged TGF-β signaling components in Nasonia vitripennis

The transforming growth factor beta (TGF)-β signaling pathway and its modulators are involved in many aspects of cellular growth and differentiation in all metazoa. Although most of the core components of the pathway are highly conserved, many lineage-specific adaptations have been observed including changes regarding paralog number, presence and absence of modulators, and functional relevance for particular processes. In the parasitic jewel wasp Nasonia vitripennis, the bone morphogenetic proteins (BMPs), one of the major subgroups of the TGF-β superfamily, play a more fundamental role in dorsoventral (DV) patterning than in all other insects studied so far. However, Nasonia lacks the BMP antagonist Short gastrulation (Sog)/chordin, which is essential for polarizing the BMP gradient along the DV axis in most bilaterian animals. Here, we present a broad survey of TGF-β signaling in Nasonia with the aim to detect other lineage-specific peculiarities and to identify potential mechanisms, which explain how BMP-dependent DV pattering occurs in the early Nasonia embryo in the absence of Sog.     

Study of possible involvement of MEK mitogen-activated protein kinase and TGF-β receptor in planarian regeneration processes using pharmacological inhibition analysis

Possible involvement of MEK mitogen-activated protein kinase and TGF-β receptor in the processes of regeneration and morphogenesis in freshwater planarian flatworms Schmidtea mediterranea was studied using a pharmacological inhibitor analysis. It was found that pharmacological inhibitors of these kinases significantly inhibit the regeneration of the head end of the animals and that this effect is realized due to inhibition of proliferative activity of neoblasts, planarian stem cells. It is shown that that the inhibition of the studied protein kinases in regenerating planarians markedly disturbs stem cell differentiation and morphogenesis.     

Legionella pneumophila infection induces programmed cell death,caspase activation,and release of high-mobility group box 1 protein in A549 alveolar epithelial cells: inhibition by methyl prednisolone

Background

Legionella pneumophila pneumonia often exacerbates acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Apoptosis of alveolar epithelial cells is considered to play an important role in the pathogenesis of ALI and ARDS. In this study, we investigated the precise mechanism by which A549 alveolar epithelial cells induced by L. pneumophila undergo apoptosis. We also studied the effect of methyl prednisolone on apoptosis in these cells.

Methods

Nuclear deoxyribonucleic acid (DNA) fragmentation and caspase activation in L. pneumophila-infected A549 alveolar epithelial cells were assessed using the terminal deoxyribonucleotidyl transferase-mediated triphosphate (dUTP)-biotin nick end labeling method (TUNEL method) and colorimetric caspase activity assays. The virulent L. pneumophila strain AA100jm and the avirulent dotO mutant were used and compared in this study. In addition, we investigated whether methyl prednisolone has any influence on nuclear DNA fragmentation and caspase activation in A549 alveolar epithelial cells infected with L. pneumophila.

Results

The virulent strain of L. pneumophila grew within A549 alveolar epithelial cells and induced subsequent cell death in a dose-dependent manner. The avirulent strain dotO mutant showed no such effect. The virulent strains of L. pneumophila induced DNA fragmentation (shown by TUNEL staining) and activation of caspases 3, 8, 9, and 1 in A549 cells, while the avirulent strain did not. High-mobility group box 1 (HMGB1) protein was released from A549 cells infected with virulent Legionella. Methyl prednisolone (53.4 μM) did not influence the intracellular growth of L. pneumophila within alveolar epithelial cells, but affected DNA fragmentation and caspase activation of infected A549 cells.

Conclusion

Infection of A549 alveolar epithelial cells with L. pneumophila caused programmed cell death, activation of various caspases, and release of HMGB1. The dot/icm system, a major virulence factor of L. pneumophila, is involved in the effects we measured in alveolar epithelial cells. Methyl prednisolone may modulate the interaction of Legionella and these cells.     

Effect of Intestinal Microbiota Alteration on Hepatic Damage in Rats with Acute Rejection After Liver Transplantation

The previous studies all focus on the effect of probiotics and antibiotics on infection after liver transplantation. Here, we focus on the effect of gut microbiota alteration caused by probiotics and antibiotics on hepatic damage after allograft liver transplantation. Brown-Norway rats received saline, probiotics, or antibiotics via daily gavage for 3 weeks. Orthotopic liver transplantation (OLT) was carried out after 1 week of gavage. Alteration of the intestinal microbiota, liver function and histopathology, serum and liver cytokines, and T cells in peripheral blood and Peyer’s patch were evaluated. Distinct segregation of fecal bacterial diversity was observed in the probiotic group and antibiotic group when compared with the allograft group. As for diversity of intestinal mucosal microbiota and pathology of intestine at 2 weeks after OLT, antibiotics and probiotics had a significant effect on ileum and colon. The population of Lactobacillus and Bifidobacterium in the probiotic group was significantly greater than the antibiotic group and the allograft group. The liver injury was significantly reduced in the antibiotic group and the probiotic group compared with the allograft group. The CD4/CD8 and Treg cells in Peyer’s patch were decreased in the antibiotic group. The intestinal Treg cell and serum and liver TGF-β were increased markedly while CD4/CD8 ratio was significantly decreased in the probiotic group. It suggested that probiotics mediate their beneficial effects through increase of Treg cells and TGF-β and deduction of CD4/CD8 in rats with acute rejection (AR) after OLT.     

Citrus alkaline extracts prevent endoplasmic reticulum stress in type II alveolar epithelial cells to ameliorate pulmonary fibrosis via the ATF3/PINK1 pathway

BackgroundIdiopathic pulmonary fibrosis is a chronic, progressive, fibrotic disease. Although the pathogenesis remains unclear, the effect of endoplasmic reticulum (ER) stress in type II alveolar epithelial cells (AEC IIs) is increasingly thought to be a critical mechanism.PurposeWe investigated the effects of citrus alkaline extracts (CAE) on AEC IIs and elucidated the underlying mechanism for their possible use in ameliorating pulmonary fibrosis (PF).MethodsA bleomycin-induced mouse model of PF, and an in vitro tunicamycin (TM) -induced ER stress model in A549 cells were successfully established. Accumulation of collagen in lung tissues in vivo was assessed using histological analysis and western blotting. The expression levels of the ER-stress marker BiP and other related proteins were assessed by western blotting and immunofluorescence staining. Mitochondrial membrane potential was assessed to evaluate mitochondrial homeostasis.ResultsCAE mitigated collagen deposition to ameliorate PF in vivo. CAE suppressed the bleomycin or TM-induced increases in ER-stress biomarker, BiP, and PERK pathway proteins, resulting in a decrease in ER stress in mouse lung tissues and A549 cells, respectively. Additionally, CAE treatment suppressed the bleomycin or TM-induced increase in the ER-stress downstream proteins, activating ATF3 and increased the levels of PINK1 in AEC IIs, both in vivo and in vitro. The reduced mitochondrial homeostasis induced by TM was restored by CAE-treatment in A549 cells. Furthermore, conditioned media from TM-treated A549 cells increased collagen deposition in MRC5 cells mainly via TGF-β1. The increased collagen deposition was not seen using conditioned media from CAE-treated A549 cells.ConclusionThese results provide novel insights into the potential mechanism of CAE in inhibiting ER stress in AEC IIs, and suggests that it has great potential to ameliorate PF via the ATF3/PINK1 pathway.     

Potential role for Ext1-dependent heparan sulfate in regulating P311 gene expression in A549 carcinoma cells

Background

Exostosin-1 (EXT1), a member of the EXT protein family, is indispensable for synthesis of heparan sulfate (HS) chains that bind to and modulate the signaling efficiency of numerous growth factor activities. We have previously shown that Ext1 mutated mouse embryonic fibroblasts produce short sulfated HS chains which dramatically influence tumor cell behavior in a 3-dimensional (3D) heterospheroid system composed of tumor cells and fibroblasts.

Region of Difference 1 in Nontuberculous Mycobacterium Species Adds a Phylogenetic and Taxonomical Character

The esat-6 and cfp-10 genes are essential for virulence in Mycobacterium tuberculosis. Among nontuberculous mycobacteria, we found these genes only in M. kansasii, M. szulgai, M. marinum, and M. riyadhense, with unique sequences. This adds a phylogenetic and taxonomical characteristic and may represent a virulence factor for nontuberculous mycobacteria.The 6-kDa early secretory antigenic target (ESAT-6) and 10-kDa culture filtrate protein (CFP-10) of Mycobacterium tuberculosis are potent T-cell antigens (2, 12). The genes encoding ESAT-6 and CFP-10 are situated within “region of difference 1” (RD1) of Mycobacterium tuberculosis but are also present in some nontuberculous mycobacteria (NTM) (2, 12). Deletion of RD1 in M. tuberculosis significantly decreases its virulence in animal models (8), suggesting that genes residing in RD1 are involved in pathogenesis. In M. tuberculosis, the RD1 proteins effect translocation to the cytosol, a mechanism for survival within macrophages (15). Therefore, RD1 in NTM may also play a crucial role in virulence.To improve our understanding of the pathogenesis of NTM disease and the possible role of RD1 in virulence, we screened a wide diversity of NTM for the presence of RD1.From our laboratory database, we retrieved isolates of all five Mycobacterium kansasii subtypes based on 16S-23S internal transcribed spacer sequencing (n = 15), M. szulgai (n = 4), M. marinum (n = 4), M. avium (n = 2), M. conspicuum (n = 4), M. genavense (n = 1), M. bohemicum (n = 2), M. interjectum (n = 2), M. flavescens (n = 5), M. xenopi (n = 2), M. malmoense (n = 2), M. riyadhense (n = 1), and M. tuberculosis H37Rv.The selection of these strains was based on their phylogenetic relationship with the M. tuberculosis complex in the multigene taxonomical model published by Devulder et al. (3).To establish the presence of an RD1-like element and sequences of the esat-6 and cfp-10 genes, we used the Esa-12 (CATGACAGAGCAGCAGTG) and Esa-303 (5′-GCCCTATGCGAACATCCC-3′) primers for esat-6 and the opBR78 (5′-GTAGCCCGGGATGGCAGAGATGAAGACCGATGCC-3′) and opBR103 (5′-TCAGAAGCCCATTTGCGAGGACAGC-3′) primers for cfp-10 (1). The M. smegmatis esat-6 and cfp-10 gene sequences were extracted from the whole-genome sequence in the GenBank database (accession number {"type":"entrez-nucleotide","attrs":{"text":"CP000480","term_id":"118168627","term_text":"CP000480"}}CP000480).Using these primers, we were able to demonstrate an RD1 for M. tuberculosis H37Rv and for all M. kansasii subtypes, M. szulgai, M. marinum, and M. riyadhense. The PCR was repeatedly negative for isolates of the remaining species, M. avium, M. conspicuum, M. genavense, M. bohemicum, M. interjectum, M. flavescens, M. xenopi, and M. malmoense. For these species, we performed Southern blotting and hybridized DNA membranes using the purified M. tuberculosis H37Rv and M. kansasii type I esat-6 amplicons as probes (1). None of the PCR-negative species hybridized with either probe (data not shown).The presence of RD1, characterized by an esat-6-like gene and an cfp-10-like gene, is a phylogenetic characteristic among the NTM. It is mainly found only among slowly growing NTM species that are phylogenetically related to the M. tuberculosis complex based on the multigene taxonomical model by Devulder et al. (3) and in the more distantly related rapid grower M. smegmatis. Possibly, the presence of RD1 reflects phylogenetic relationships to the M. tuberculosis complex.Previous authors have recorded the presence of RD1 in M. flavescens (1). We were unable to demonstrate it in four reference strains (ATCC 23008, ATCC 23033, ATCC 23035, and ATCC 23039) and a clinical isolate. Thus, with its presence of an RD1 region, M. smegmatis still stands out among the rapid growing NTM.Gey van Pittius et al. have demonstrated the presence of the ESX-5 locus, which they assume is a product of duplication of RD1 and its secretion system (ESX-1), in most slow-growing NTM species (5). Our results seem to suggest that in many slow growers, after this duplication, the original ESX-1 either was lost or has undergone extensive mutation, barring hybridization.All five subtypes of M. kansasii had distinct esat-6 and cfp-10 sequences; type three was subdivided into two separate lineages based on both esat-6 and cfp-10 sequences. Among M. marinum and M. szulgai strains, no difference was noted, and the sequences obtained for M. riyadhense were unique. We aligned the esat-6 and cfp-10 gene sequences separately and concatenated, using the Clustal X software program (14). The resulting topology and tree, inferred by neighbor joining and visualized using the MEGA 4.0 software package (13), were evaluated by bootstrap analyses based on 1,000 resamplings. The resulting trees are shown in Fig. ​Fig.1A1A (esat-6), B (cfp-10), and C (esat-6 and cfp-10 concatenated). From these trees, it is obvious that the slow-growing RD1-positive NTM have esat-6 and cfp-10 sequences much more closely related to those of M. tuberculosis than to those of M. smegmatis (Fig. 1A to C).Open in a separate windowFIG. 1.Phylogenetic trees based on multiple sequence alignment of esat-6 (A), cfp-10 (B), and concatenated esat-6 and cfp-10 (C) sequences. The neighbor-joining tree was created and bootstrapped 1,000× with CLUSTALX and visualized with MEGA 4.0 (13, 14). Bootstrap values are indicated at the nodes.Thus, the presence of RD1 in these slow growers marks a genetically closely related Mycobacterium grouping, and sequencing of RD1 is a tool for (sub)species identification. Therefore, we propose that future introduction of new species phylogenetically related to the RD1-positive grouping should include an investigation of RD1 presence and gene sequences.Deletion of RD1 lowers the virulence of M. tuberculosis complex bacteria (8, 9, 11). Although the presence of RD1 may thus be important for virulence, we were not able to detect this genomic region in well-known causative agents of disease in humans, including M. avium and M. malmoense (7, 12). In M. smegmatis, ESAT-6 and CFP-10 secretion has a role in conjugation, rather than translocation to the cytosol, by which M. tuberculosis survives within macrophages (4, 15). The remaining NTM species that harbor RD1 are phylogenetically more closely related to M. tuberculosis than to M. smegmatis (3), which is also expressed in their esat-6 and cfp-10 sequences (Fig. ​(Fig.1).1). Moreover, M. kansasii, M. szulgai, and M. marinum are considered the most pathogenic among the NTM (1, 6, 16). Therefore, RD1 may play a role in virulence of these NTM.The RD1 sequences differed between M. kansasii type 1, an important causative agent of NTM disease, and the other types, which are less involved or not involved in human disease (1). Clinically relevant and nonrelevant M. szulgai isolates, determined using the American Thoracic Society diagnostic criteria (6, 16), shared identical sequences. The RD1 presence and gene sequences and thus the protein structure do not provide a complete explanation of the virulences of the different NTM. Presumably, host factors and pathogen factors other than RD1 presence are also important. In vitro infection experiments are necessary to clarify the role of RD1-containing slow-growing NTM.Demonstration and characterization of RD1 in NTM have gained significance with the advent of the gamma interferon release assays (IGRAs) for the diagnosis of (latent) tuberculosis. These assays measure gamma interferon production and release by patients'' T lymphocytes after incubation with the ESAT-6 and CFP-10 antigens of M. tuberculosis (10). The presence of similar antigens in NTM and thus recognition of these antigens by patients infected by these NTM theoretically lowers the specificity of the IGRAs in diagnosing latent tuberculosis.In conclusion, an RD1 element, similar to that of M. tuberculosis, is present in M. kansasii, M. szulgai, M. marinum, and M. riyadhense. The presence of RD1 in general is a phylogenetic and taxonomical characteristic of NTM, which hints at a phylogenetic relationship with the M. tuberculosis complex. The RD1 sequence analysis enables distinction to the species or subspecies level. Future studies describing related new species should investigate RD1 presence and gene sequences. The role of RD1 as a virulence factor and the impact of RD1-containing NTM on functioning of the IGRAs should be the subjects of further studies.     

Anti-tuberculosis lead molecules from natural products targeting <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> ClpC1

Tuberculosis (TB) is a serious and potentially fatal disease caused by Mycobacterium tuberculosis (M. tb). The occurrence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) M. tb is a significant public health concern because most of the anti-TB drugs that have been in use for over 40 years are no longer effective for the treatment of these infections. Recently, new anti-TB lead compounds such as cyclomarin A, lassomycin, and ecumicin, which are cyclic peptides from actinomycetes, have shown potent anti-TB activity against MDR and XDR M. tb as well as drug-susceptible M. tb in vitro. The target molecule of these antibiotics is ClpC1, a protein that is essential for the growth of M. tb. In this review, we introduce the three anti-TB lead compounds as potential anti-TB therapeutic agents targeting ClpC1 and compare them with the existing anti-TB drugs approved by the US Food and Drug Administration.     

TLR3 promotes MMP-9 production in primary human airway epithelial cells through Wnt/β-catenin signaling

Background

Airway epithelial cells (AEC) act as the first line of defence in case of lung infections. They constitute a physical barrier against pathogens and they participate in the initiation of the immune response. Yet, the modalities of pathogen recognition by AEC and the consequences on the epithelial barrier remain poorly documented.

Method

We investigated the response of primary human AEC to viral (polyinosinic-polycytidylic acid, poly(I:C)) and bacterial (lipopolysaccharide, LPS) stimulations in combination with the lung remodeling factor Transforming Growth Factor-β (TGF-β).

Results

We showed a strong production of pro-inflammatory cytokines (Interleukin (IL)-6, Tumor Necrosis Factor α, TNFα) or chemokines (CCL2, CCL3, CCL4, CXCL10, CXCL11) by AEC stimulated with poly(I:C). Cytokine and chemokine production, except CXCL10, was Toll Like Receptor (TLR)-3 dependent and although they express TLR4, we found no cytokine production after LPS stimulation. Poly(I:C), but not LPS, synergised with TGF-β for the production of matrix metalloproteinase-9 (MMP-9) and fibronectin. Mechanistic analyses suggest the secretion of Wnt ligands by AEC along with a degradation of the cellular junctions after poly(I:C) exposure, leading to the release of β-catenin from the cell membrane and stimulation of the Wnt/β-catenin pathway.

Conclusion

Our results highlight the cross talk between TGF-β and TLR signaling in bronchial epithelium and its impact on the remodeling process.