Roles of autophagy in killing of mycobacterial pathogens by host macrophages - Effects of some medicinal plants.

Autophagy is a cellular stress-induced intracellular process, through which damaged cellular components are decomposed via lysosomal degradation. This process plays important roles in host innate immunity, particularly the elimination of intracellular pathogens inside host macrophages. A more detailed understanding of the roles of autophagic events in the effective manifestation of macrophagic antimycobacterial activity is needed.

Immunoadjunctive Therapy against Bacterial Infections Using Herbal Medicines Based on Th17 Cell-mediated Protective Immunity.

One of the major health concerns in the world is the global increase in intractable bacterial infectious diseases due to the emergence of multi- and extensively drug-resistant bacterial pathogens as well as increase in compromised hosts around the world. Particularly, in the case of mycobacteriosis, the high incidence of tuberculosis in developing countries, resurgence of tuberculosis in industrialized countries, and increase in the prevalence of Mycobacterium avium complex infections are important worldwide health concerns. However, the development of novel antimycobacterial drugs is currently making slow progress.

Hypascyrins A-E, Prenylated Acylphloroglucinols from .

Six new prenylated acylphloroglucinols with menthane moieties, hypascyrins A-E (-) and -hyphenrone J (), together with four known analogues, were isolated from roots. Detailed spectroscopic data analyses resulted in the assignment of their structures. The absolute configuration of was deduced by experimental and calculated ECD data, while those of - were assigned by ECD data analyses as well as chemical conversions.

Clinical and Basic Studies on Therapeutic Efficacy of Herbal Medicines against Mycobacterial Infections.

The high incidence of tuberculosis (TB) in developing countries, the resurgence of TB in industrialized countries, and the worldwide increase in the prevalence of complex infections are important global health concerns. However, the development of novel antimycobacterial drugs is currently making very slow progress. Therefore, it is considered that devising improved administration protocols for clinical treatment against intractable mycobacteriosis using existing chemotherapeutics is more practical than awaiting the development of new antimycobacterial drugs.

Inhibition of tumor formation and metastasis by a monoclonal antibody against lymphatic vessel endothelial hyaluronan receptor 1.

Although cancer metastasis is associated with poor prognosis, the mechanisms of this event, especially via lymphatic vessels, remain unclear. Lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) is expressed on lymphatic vessel endothelium and is considered to be a specific marker of lymphatic vessels, but it is unknown how LYVE-1 is involved in the growth and metastasis of cancer cells. We produced rat monoclonal antibodies (mAb) recognizing the extracellular domain of mouse LYVE-1, and investigated the roles of LYVE-1 in tumor formation and metastasis.

Identification of Novel Mycobacterial Inhibitors Against Mycobacterial Protein Kinase G.

Protein kinase G (PknG) is a eukaryotic-like serine/threonine kinase that is expressed by and promotes survival of mycobacteria in host macrophages by suppressing phagosome-lysosome fusion. Thus, compounds showing inhibitory activity against PknG are promising anti-mycobacterial agents. We therefore aimed to develop anti-mycobacterial agents by identifying new PknG inhibitors.

Anti-Mycobacterium avium complex activity of clarithromycin, rifampin, rifabutin, and ethambutol in combination with adenosine 5'-triphosphate.

We previously reported that adenosine 5'-triphosphate (ATP) inhibited the growth of various bacteria, including mycobacteria, Staphylococcus, and Pseudomonas, without damaging bacterial surface structures. Notably, ATP's antibacterial activity was found to be attributable to its iron-chelating ability. ATP exhibited combined effects with some antimicrobials against Mycobacterium intracellulare and methicillin-resistant S.

Host-Directed Therapeutics against Mycobacterial Infections.

The high incidence of tuberculosis (TB) in the world, especially in developing countries, the resurgence of TB in industrialized countries, and the global increase in the prevalence of Mycobacterium avium complex infections in immunocompromised hosts have prompted the quest for novel antimycobacterial drugs. However, the development of such antimicrobial chemotherapeutics is currently making very slow progress even with using the bioinformatics-based methodology for drug design. It thus appears that devising improved administration protocols for clinical treatment against intractable mycobacterial infections using existing chemotherapeutics is more practical than awaiting the development of new antimycobacterial drugs.

Hypatulins A and B, Meroterpenes from Hypericum patulum.

Two novel prenylated benzophenone related meroterpenes, hypatulins A (1) and B (2), were isolated from the leaves of Hypericum patulum. The structures of 1 and 2 were assigned by spectroscopic analysis, chemical conversion, and calculations of the ECD (electron circular dichroism) spectra. Hypatulin A (1) had a unique densely substituted tricyclic octahydro-1,5-methanopentalene core, while hypatulin B (2) possessed a bicyclo[3.

Erecricins A-E, prenylated acylphloroglucinols from the roots of Hypericum erectum.

Six new prenylated acylphloroglucinols, erecricins A-E (1-5) and adotogirin (6), were isolated from the roots of Hypericum erectum (Hypericaceae). Their structures were assigned on the basis of spectroscopic evidences. Erecricins A-E (1-5) are bicyclic prenylated acylphloroglucinols possessing a chromane or a chromene skeleton.

[M1 AND M2 MACROPHAGE POPULATIONS: THOSE INDUCED AND ACTIVATED BY MYCOBACTERIAL INFECTIONS].

In the advanced stages of mycobacterial infections, host immune systems tend to change from a Th1-type to Th2-type immune response, resulting in the abrogation of Th1 cell- and macrophage-mediated antimicrobial host protective immunity. Notably, this type of immune conversion is occasionally associated with the generation of. certain types of suppressor macrophage populations.

Aldose reductase participates in the downregulation of T cell functions due to suppressor macrophages.

The cell-to-cell contact of T lymphocytes with immunosuppressive macrophages causes marked changes in the tyrosine phosphorylation of some cytosolic proteins of T cells. By phosphoproteome analysis, we identified a 36-kDa protein as aldose reductase (AR). The AR expression in T cells was not changed by TCR stimulation or due to cell-to-cell transmission of suppressor signals from immunosuppressive macrophages.

ATP exhibits antimicrobial action by inhibiting bacterial utilization of ferric ions.

ATP up-regulates macrophage antimycobacterial activity in a P2X7-dependent manner, but little is known about whether ATP directly exhibits antimicrobial effects against intracellular mycobacteria. In this study, we found that ATP inhibited the growth of various bacteria, including Staphylococcus, Pseudomonas, and mycobacteria, without damaging bacterial surface structures. Using gene technology, we newly established an enterobactin-deficient (entB(-)) mutant from ATP-resistant Klebsiella pneumoniae, and found the recovery of ATP susceptibility in the enterobactin-deleted mutant.

In vivo crystallography at X-ray free-electron lasers: the next generation of structural biology?

The serendipitous discovery of the spontaneous growth of protein crystals inside cells has opened the field of crystallography to chemically unmodified samples directly available from their natural environment. On the one hand, through in vivo crystallography, protocols for protein crystal preparation can be highly simplified, although the technique suffers from difficulties in sampling, particularly in the extraction of the crystals from the cells partly due to their small sizes. On the other hand, the extremely intense X-ray pulses emerging from X-ray free-electron laser (XFEL) sources, along with the appearance of serial femtosecond crystallography (SFX) is a milestone for radiation damage-free protein structural studies but requires micrometre-size crystals.

Unique macrophages different from M1/M2 macrophages inhibit T cell mitogenesis while upregulating Th17 polarization.

Mycobacterial infection induces suppressor macrophages (MΦs), causing disease exacerbation. There are two major MΦ subsets (M1 and M2 MΦs) that are phenotypically and functionally different. Here, we examined which of the MΦ subsets the mycobacterial infection-induced suppressor MΦs (MIS-MΦs) belong to.

[Phagocytosis of Mycobacterium leprae down-regulates anti-microbial activity of murine macrophages against Mycobacterium intracellulare].

Patients with highly bacillated lepromatous leprosy (LL) essentially lack T cell-mediated immune responses specific to Mycobacterium leprae (ML) antigens, resulting in severely impaired host resistance to leprosy bacilli. Such type of immune unresponsiveness characteristic of LL patients is mainly attributable to markedly depressed T cell ability to activate/expand in response to ML antigens. In this study, we examined profiles of antimycobacterial activity of macrophages, which phagocytized leprosy bacilli, because there is another possibility that, in LL patients, host macrophages in the leprosy lesions are impaired in their antimicrobial activity due to their interaction with infected leprosy bacilli, particularly cellular events through binding with and/or internalization of the pathogens, thereby causing the reduction in host resistance to ML pathogens.

Characteristics of suppressor macrophages induced by mycobacterial and protozoal infections in relation to alternatively activated M2 macrophages.

In the advanced stages of mycobacterial infections, host immune systems tend to change from a Th1-type to Th2-type immune response, resulting in the abrogation of Th1 cell- and macrophage-mediated antimicrobial host protective immunity. Notably, this type of immune conversion is occasionally associated with the generation of certain types of suppressor macrophage populations. During the course of Mycobacterium tuberculosis (MTB) and Mycobacterium avium-intracellulare complex (MAC) infections, the generation of macrophages which possess strong suppressor activity against host T- and B-cell functions is frequently encountered.

Comparative in vitro and in vivo antimicrobial activities of sitafloxacin, gatifloxacin and moxifloxacin against Mycobacterium avium.

Moxifloxacin exhibits therapeutic activity against Mycobacterium avium infection in mice. Since not only moxifloxacin but also another 8-methoxy quinolone, gatifloxacin, and a C-8-chloro quinolone, sitafloxacin, show favourable antimycobacterial activity in vitro, their anti-M. avium activities were compared in vivo.

Development of new antituberculous drugs based on bacterial virulence factors interfering with host cytokine networks.

The worldwide increase in the prevalence of tuberculosis (TB), especially multidrug-resistant TB and extensively drug-resistant TB, is an important global health concern, and new effective drugs are urgently needed. Information on the genome of Mycobacterium tuberculosis (MTB) and various mycobacterial virulence genes is leading to the identification of genes that code for new drug targets. Mycobacterium tuberculosis (MTB) is resistant to the antimicrobial mechanisms of host macrophages and can survive and replicate in macrophages for long periods, resulting in a persistent infection.

Properties of immunosuppressive macrophages generated by Mycobacterium intracellulare infection in M. intracellulare-susceptible and resistant mice.

Splenic macrophages (M(phi)s) generated in Mycobacterium intracellulare (Min)-infected mice exhibit suppressor activity against T cell mitogenesis. We examined profiles of the Min-induced generation of immunosuppressive M(phi)s (Min-M(phi)s) in Min-susceptible BALB/c (bcg(s)) and resistant CBA/JN (bcg(r)) mice. Min infection in BALB/c mice caused a more rapid generation of the immunosuppressive M(phi)s, which expressed M(phi) markers such as CD11b and F4/80, exhibited an increased ability to generate reactive oxygen intermediates, and inhibited IL-2 receptor expression by mitogenic T cells, than did Min infection in CBA/JN mice.

Recent advances in antituberculous drug development and novel drug targets.

TB, especially multidrug-resistant TB and extensively drug-resistant TB, is an important global health concern, and the novel development of effective anti-tuberculous drugs is urgently needed. Newly elucidated, critical information on the entire genome of Mycobacterium tuberculosis (MTB) and advances in knowledge regarding various mycobacterial virulence genes are promoting progression in the identification of genes that code for new drug targets. With this background, this review deals with the following areas: first, the future development of new anti-tuberculous drugs is discussed according to the potential pharmacological targets of MTB; and second, a review of the present development status of new anti-tuberculous drugs is conducted, particularly focusing on some promising new anti-tuberculous agents, such as nitroimidazoles, diarylquinolines and oxazolidinones.

Tropoelastin regulates chemokine expression in fibroblasts in Costello syndrome.

Costello syndrome is a multiple congenital anomaly associated with growth and mental retardation, cardiac and skeletal anomalies, and a predisposition to develop neoplasia. Comprehensive expression analysis revealed remarkable up-regulation of several cytokines and chemokines including Gro family proteins, interleukin-1beta (IL-1beta), IL-8 and MCP-1 but down-regulation of extracellular matrix components including collagens and proteoglycans of skin fibroblasts derived from a Japanese Costello syndrome patient characterized by significantly reduced tropoelastin mRNA, impaired elastogenesis and enhanced cell proliferation. In contrast, decreases in these chemokines and IL-1beta expression were observed in Costello fibroblastic cell lines stably expressing the bovine tropoelastin (btEln) gene and in restored elastic fibers.

[Profiles of intracellular expression, distribution, and activation of phospholipase A2 in host macrophages infected with Mycobacterium avium complex].

Our recent studies have shown that type IV cytosolic phospholipase A2 (cPLA2) plays an important role in the expression of macrophage (MPh) antimicrobial activity against the Mycobacterium avium complex (MAC). To clarify the modes of cPLA2 participation in MPh anti-MAC antimicrobial function in detail, we studied intracellular profiles of phospholilase A2, focusing on cPLA2, in MAC-infected MPhs, with the following findings: In murine peritoneal MPhs, cPLA2 was constitutively expressed even in uninfected MPhs, and MAC infection did not increase intramacrophage cPLA2 expression. In an RAW264.