High dose of Mycobacterium tuberculosis (Mtb) strain H37Rv administered by intratracheal injection in BALB/c mice induce progressive tuberculosis (TB). In this model, during the first month there is ...a temporal control of bacillary growth, in coexistence with macrophage activation, granuloma formation and Th‐1 response. Then, bacterial proliferation recommences, accompanied by progressive pneumonia and decreasing expression of protective cytokines (IFN‐γ and TNF‐α). In this model, we studied the IL‐12 gene expression kinetics and cellular source. There is a rapid and progressive IL‐12 expression peaking at day 14, when granulomas start their formation and numerous macrophages show strong IL‐12 immunostaining, while during progressive TB there is a significant decrease of IL‐12 expression and occasional macrophages showed IL‐12 immunolabeling. In the second part of this study, we determined the immunotherapeutic effect of recombinant adenoviruses that codify IL‐12 (AdIL‐12). Intratracheal administration of only one dose of AdIL‐12 one day before Mtb infection produced significant decrease of bacterial loads, lesser pneumonia and higher expression of TNF‐α, IFN‐γ and iNOS. When only one dose of AdIL‐12 was given in healthy mice cohoused with infected mice with highly virulent and transmissible Mtb, total prevention of infection was conferred. Moreover, when AdIL‐12 was administered by intranasal route in animals suffering late active TB after 2 months of infection, a very low pulmonary bacilli burdens was detected. These experimental data confirm that IL‐12 is a significant cytokine in the immune protection against Mtb, and gene therapy based in adenoviruses coding this cytokine increased protective immunity and prevent Mtb transmission.
The emergence and spread of drug-resistant
strains possibly threaten our ability to treat this disease in the future. Even though two new antitubercular drugs have recently been introduced, there is ...still the need to design new molecules whose mechanisms of action could reduce the length of treatment. We show that two alternative sigma factors of
(SigE and SigB) have a major role in determining the level of basal resistance to several drugs and the amount of persisters surviving long-duration drug treatment. We also demonstrate that ethambutol, a bacteriostatic drug, is highly bactericidal for
mutants missing either SigE or SigB. We suggest that molecules able to interfere with the activity of SigE or SigB not only could reduce
virulence
but also could boost the effect of other drugs by increasing the sensitivity of the organism and reducing the number of persisters able to escape killing.
Summary
Tuberculosis (TB) is the leading cause of death from a single bacterial infectious agent and is one of the most relevant issues of public health. Another pandemic disease is type II diabetes ...mellitus (T2D) that is estimated to affect half a billion people in the world. T2D is directly associated with obesity and a sedentary lifestyle and is frequently associated with immunosuppression. Immune dysfunction induced by hyperglycemia increases infection frequency and severity. Thus, in developing countries the T2D/TB co‐morbidity is frequent and represents one of the most significant challenges for the health‐care systems. Several immunoendocrine abnormalities are occurring during the chronic phase of both diseases, such as high extra‐adrenal production of active glucocorticoids (GCs) by the activity of 11‐β‐hydroxysteroid dehydrogenase type 1 (11‐βHSD1). 11‐βHSD1 catalyzes the conversion of inactive cortisone to active cortisol or corticosterone in lungs and liver, while 11‐β‐hydroxysteroid dehydrogenase type 2 (11‐βHSD2) has the opposite effect. Active GCs have been related to insulin resistance and suppression of Th1 responses, which are deleterious factors in both T2D and TB. The anabolic adrenal hormone dehydroepiandrosterone (DHEA) exerts antagonistic effects on GC signaling in immune cells and metabolic tissues; however, its anabolic effects prohibit its use to treat immunoendocrine diseases. 16α‐bromoepiandrosterone (BEA) is a water miscible synthetic sterol related to DHEA that lacks an anabolic effect while amplifying the immune and metabolic properties with important potential therapeutic uses. In this work, we compared the expression of 11‐βHSD1 and the therapeutic efficacy of BEA in diabetic mice infected with tuberculosis (TB) (T2D/TB) with respect to non‐diabetic TB‐infected mice (TB). T2D was induced by feeding mice with a high‐fat diet and administering a single low‐dose of streptozotocin. After 4 weeks of T2D establishment, mice were infected intratracheally with a high‐dose of Mycobacterium tuberculosis strain H37Rv. Then, mice were treated with BEA three times a week by subcutaneous and intratracheal routes. Infection with TB increased the expression of 11‐βHSD1 and corticosterone in the lungs and liver of both T2D/TB and TB mice; however, T2D/TB mice developed a more severe lung disease than TB mice. In comparison with untreated animals, BEA decreased GC and 11‐βHSD1 expression while increasing 11‐βHSD2 expression. These molecular effects of BEA were associated with a reduction in hyperglycemia and liver steatosis, lower lung bacillary loads and pneumonia. These results uphold BEA as a promising effective therapy for the T2D/TB co‐morbidity.
Study of immune‐endocrine relation between diabetes and their relationship in tuberculosis susceptibility.
The relation between men and women suffering pulmonary tuberculosis is 7/3 in favor to males. Sex hormones could be a significant factor for this difference, considering that testosterone impairs ...macrophage activation and pro-inflammatory cytokines production, while estrogens are proinflammatory mediator's inducer. The aim of this work was to compare the evolution of tuberculosis in male and female mice using a model of progressive disease. BALB/c mice, male and female were randomized into two groups: castrated or sham-operated, and infected by the intratracheal route with a high dose of Mycobacterium tuberculosis strain H37Rv. Mice were euthanized at different time points and in their lungs were determined bacilli loads, inflammation, cytokines expression, survival and testosterone levels in serum. Non-castrated male mice showed significant higher mortality and bacilli burdens during late disease than female and castrated male animals. Compared to males, females and castrated males exhibited significant higher inflammation in all lung compartments, earlier formation of granulomas and pneumonia, while between castrated and non-castrated females there were not significant differences. Females and castrated males expressed significant higher TNF-α, IFN γ, IL12, iNOS and IL17 than non-castrated males during the first month of infection. Serum Testosterone of males showed higher concentration during late infection. Orchidectomy at day 60 post-infection produced a significant decrease of bacilli burdens in coexistence with higher expression of TNFα, IL-12 and IFNγ. Thus, male mice are more susceptible to tuberculosis than females and this was prevented by castration suggesting that testosterone could be a tuberculosis susceptibility factor.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
As components of the innate immune response, antimicrobial peptides (AMPs) efficiently contribute to infection control and maintenance of a latent state in pulmonary tuberculosis (TB). As a ...therapeutic strategy, the administration of recombinant AMPs could be limited by enzymatic degradation and high production costs. Likewise, strategies based on the induction of AMPs have generated controversial results. In this study, 2 recombinant type‐5 adenoviruses (Ad) expressing the human β‐defensin 3 (HβD3) or cathelicidin (LL37) were assessed in a murine pulmonary TB model. Mice infected with either a high dose of a drug‐sensitive (H37Rv) or a multidrug‐resistant (MDR) strain of Mycobacterium tuberculosis (Mtb) were treated with a single administration of AdHβD3, AdLL37, AdGFP (control vector expressing a green fluorescent protein), or saline solution (SS). Lungs were obtained to determine the bacterial burden, histologic damage, and cytokine expression at different time points. Mice treated with AdHβD3 or AdLL37 showed significantly lower bacterial load and pneumonia, and higher proinflammatory cytokine expression than the control groups AdGFP and SS. A synergistic therapeutic effect could be observed when first‐ or second‐line antibiotics (ABs) were administered with adenoviral therapy in animals infected with H37Rv or MDR strains, respectively. Adenovirus‐delivered AMP's administration constitutes a promising adjuvant therapy for current anti‐TB drugs by enhancing a protective immune response and potentially reducing current AB regimes' duration.
Graphical
Adenovirus‐delivered antimicrobial peptide administration constitutes a promising adjuvant therapy for current anti‐TB drugs by enhancing a protective immune response and potentially reducing current antibiotic regimes' duration.
Tuberculosis (TB) is one of the deadliest infectious diseases in humankind history. Although, drug sensible TB is slowly decreasing, at present the rise of TB cases produced by multidrug‐resistant ...(MDR) and extensively drug‐resistant strains is a big challenge. Thus, looking for new therapeutic options against these MDR strains is mandatory. In the present work, we studied, in BALB/c mice infected with MDR strain, the therapeutic effect of supra‐pharmacological doses of the conventional primary antibiotics rifampicin and isoniazid (administrated by gavage or intratracheal routes), in combination with recombinant human hepatocyte growth factor (HGF). This high dose of antibiotics administered for 3 months, overcome the resistant threshold of the MDR strain producing a significant reduction of pulmonary bacillary loads but induced liver damage, which was totally prevented by the administration of HGF. To address the long‐term efficiency of this combined treatment, groups of animals after 1 month of treatment termination were immunosuppressed by glucocorticoid administration and, after 1 month, mice were euthanized, and the bacillary load was determined in lungs. In comparison with animals treated only with a high dose of antibiotics, animals that received the combined treatment showed significantly lower bacterial burdens. Thus, treatment of MDR‐TB with very high doses of primary antibiotics particularly administrated by aerial route can produce a very good therapeutic effect, and its hepatic toxicity can be prevented by the administration of HGF, becoming in a new treatment modality for MDR‐TB.
HGF protects the liver from anti‐tuberculosis drugs toxicity HGF potentiates the pharmacological effects of anti‐tuberculosis drugs HGF differentially modulates ROS content in the liver and the lungs
Mycobacterium tuberculosis has developed diverse mechanisms to survive inside phagocytic cells, such as macrophages. Phagocytosis is a key process in eliminating invading pathogens; thus, M. ...tuberculosis efficiently disrupts phagosome maturation to ensure infection. However, inflammatory cytokines produced by macrophages in response to early M. tuberculosis infection are key to promoting bacterial clarification. IFN‐γ enhances M. tuberculosis engulfment and destruction by reprogramming macrophages from phagocytosis to macropinocytosis. Here, we show that the transcription factor Krüppel‐like factor 10 (Klf10) plays a positive role in M. tuberculosis survival and infection by negatively modulating IFN‐γ levels. Naïve Klf10‐deficient macrophages produce more IFN‐γ upon stimulation than wild‐type macrophages, thus enhancing bacterial uptake and bactericidal activity achieved by macropinocytosis. Moreover, Klf10⁻/⁻ macrophages showed cytoplasmic distribution of coronin 1 correlated with increased pseudopod count and length. In agreement with these observations, Klf10⁻/⁻ mice showed improved bacterial clearance from the lungs and increased viability. Altogether, our data indicate that Klf10 plays a critical role in M. tuberculosis survival by preventing macrophage reprogramming from phagocytosis to macropinocytosis by negatively regulating IFN‐γ production upon macrophage infection.
Graphical
By inducing Klf10 expression, Mycobacterium tuberculosis decreases INF‐γ production and impairs an INF‐γ‐mediated autocrine loop that promotes macrophages macropinocytosis, thus favoring survival and infection.
Tuberculosis (TB) caused by Mycobacterium tuberculosis mainly affects the lungs, but can spread to other organs. TB chronically activates the immune and endocrine systems producing remarkable ...functional changes.So far, it is unknown whether pulmonary non-disseminated TB cause changes in the female reproductive system and lung endocrinology.
To investigate whether pulmonary TB produces immunoendocrine alterations of the female mice reproductive organs, and lung estradiol synthesis.
BALB/c mice were infected intratracheally with Mycobacterium tuberculosis (Mtb) strain H37Rv. Groups of six non-infected and infected animals were euthanized on different days. Bacillary loads were determined in the lungs, ovaries and uterus. Immunohistochemistry and morphometry studies were performed in histological sections. Serum estradiol wasassayed, and supernatantfrom cultured lung cells was analyzed by Thin Layer Chromatography (TLC).
Mtb only grew in lung tissue. Histopathology revealed abnormal folliculogenesis and decreased corpora lutea. Altered ovarian expression of IL-6, IL-1β was found. The infection increased serum estradiol. Estradiol synthesis by infected lung cells triplicate after 30 pi days.Aromatase immunostaining was found in the alveolar and bronchial epithelium, being stronger in the infected lungs, mainly in macrophages.
Pulmonary TB affects the histophysiology of the female reproductive system in absence of its local infection, and disturbslung endocrinology.
Mycobacterium tuberculosis (MTB) is the principal cause of human tuberculosis (TB), which is a serious health problem worldwide. The development of innovative therapeutic modalities to treat TB is ...mainly due to the emergence of multi drug resistant (MDR) TB. Autophagy is a cell-host defense process. Previous studies have reported that autophagy-activating agents eliminate intracellular MDR MTB. Thus, combining a direct antibiotic activity against circulating bacteria with autophagy activation to eliminate bacteria residing inside cells could treat MDR TB. We show that the synthetic peptide, IP-1 (KFLNRFWHWLQLKPGQPMY), induced autophagy in HEK293T cells and macrophages at a low dose (10 μM), while increasing the dose (50 μM) induced cell death; IP-1 induced the secretion of TNFα in macrophages and killed Mtb at a dose where macrophages are not killed by IP-1. Moreover, IP-1 showed significant therapeutic activity in a mice model of progressive pulmonary TB. In terms of the mechanism of action, IP-1 sequesters ATP in vitro and inside living cells. Thus, IP-1 is the first antimicrobial peptide that eliminates MDR MTB infection by combining four activities: reducing ATP levels, bactericidal activity, autophagy activation, and TNFα secretion.
The global control of Tuberculosis remains elusive, and Bacillus Calmette-Guérin (BCG) -the most widely used vaccine in history-has proven insufficient for reversing this epidemic. Several authors ...have suggested that the mass presence of vaccinated hosts might have affected the
(MTB) population structure, and this could in turn be reflected in a prevalence of strains with higher ability to circumvent BCG-induced immunity, such as the recent Beijing genotype. The effect of vaccination on vaccine-escape variants has been well-documented in several bacterial pathogens; however the effect of the interaction between MTB strains and vaccinated hosts has never been previously described. In this study we show for the first time the interaction between MTB Beijing-genotype strains and BCG-vaccinated hosts. Using a well-controlled murine model of progressive pulmonary tuberculosis, we vaccinated BALB/c mice with two different sub-strains of BCG (BCG-Phipps and BCG-Vietnam). Following vaccination, the mice were infected with either one of three selected MTB strains. Strains were selected based on lineage, and included two Beijing-family clinical isolates (strains 46 and 48) and a well-characterized laboratory strain (H37Rv). Two months after infection, mice were euthanized and the bacteria extracted from their lungs. We characterized the genomic composite of the bacteria before and after exposure to vaccinated hosts, and also characterized the local response to the bacteria by sequencing the lung transcriptome in animals during the infection. Results from this study show that the interaction within the lungs of the vaccinated hosts results in the selection of higher-virulence bacteria, specifically for the Beijing genotype strains 46 and 48. After exposure to the BCG-induced immune response, strains 46 and 48 acquire genomic mutations associated with several virulence factors. As a result, the bacteria collected from these vaccinated hosts have an increased ability for immune evasion, as shown in both the host transcriptome and the histopathology studies, and replicates far more efficiently compared to bacteria collected from unvaccinated hosts or to the original-stock strain. Further research is warranted to ascertain the pathways associated with the genomic alterations. However, our results highlight novel host-pathogen interactions induced by exposure of MTB to BCG vaccinated hosts.
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