Host-Derived Lipids from Tuberculous Pleurisy Impair Macrophage Microbicidal-Associated Metabolic Activity.

Mycobacterium tuberculosis (Mtb) regulates the macrophage metabolic state to thrive in the host, yet the responsible mechanisms remain elusive. Macrophage activation toward the microbicidal (M1) program depends on the HIF-1α-mediated metabolic shift from oxidative phosphorylation (OXPHOS) toward glycolysis. Here, we ask whether a tuberculosis (TB) microenvironment changes the M1 macrophage metabolic state. We expose M1 macrophages to the acellular fraction of tuberculous pleural effusions (TB-PEs) and find lower glycolytic activity, accompanied by elevated levels of OXPHOS and bacillary load, compared to controls. The eicosanoid fraction of TB-PE drives these metabolic alterations. HIF-1α stabilization reverts the effect of TB-PE by restoring M1 metabolism. Furthermore, Mtb-infected mice with stabilized HIF-1α display lower bacillary loads and a pronounced M1-like metabolic profile in alveolar macrophages (AMs). Collectively, we demonstrate that lipids from a TB-associated microenvironment alter the M1 macrophage metabolic reprogramming by hampering HIF-1α functions, thereby impairing control of Mtb infection.

Fatty acid oxidation of alternatively activated macrophages prevents foam cell formation, but Mycobacterium tuberculosis counteracts this process via HIF-1α activation.

The ability of Mycobacterium tuberculosis (Mtb) to persist inside host cells relies on metabolic adaptation, like the accumulation of lipid bodies (LBs) in the so-called foamy macrophages (FM), which are favorable to Mtb. The activation state of macrophages is tightly associated to different metabolic pathways, such as lipid metabolism, but whether differentiation towards FM differs between the macrophage activation profiles remains unclear. Here, we aimed to elucidate whether distinct macrophage activation states exposed to a tuberculosis-associated microenvironment or directly infected with Mtb can form FM. We showed that the triggering of signal transducer and activator of transcription 6 (STAT6) in interleukin (IL)-4-activated human macrophages (M(IL-4)) prevents FM formation induced by pleural effusion from patients with tuberculosis. In these cells, LBs are disrupted by lipolysis, and the released fatty acids enter the ß-oxidation (FAO) pathway fueling the generation of ATP in mitochondria. Accordingly, murine alveolar macrophages, which exhibit a predominant FAO metabolism, are less prone to become FM than bone marrow derived-macrophages. Interestingly, direct infection of M(IL-4) macrophages with Mtb results in the establishment of aerobic glycolytic pathway and FM formation, which could be prevented by FAO activation or inhibition of the hypoxia-inducible factor 1-alpha (HIF-1α)-induced glycolytic pathway. In conclusion, our results demonstrate that Mtb has a remarkable capacity to induce FM formation through the rewiring of metabolic pathways in human macrophages, including the STAT6-driven alternatively activated program. This study provides key insights into macrophage metabolism and pathogen subversion strategies.

Tuberculosis Exacerbates HIV-1 Infection through IL-10/STAT3-Dependent Tunneling Nanotube Formation in Macrophages.

The tuberculosis (TB) bacillus, Mycobacterium tuberculosis (Mtb), and HIV-1 act synergistically; however, the mechanisms by which Mtb exacerbates HIV-1 pathogenesis are not well known. Using in vitro and ex vivo cell culture systems, we show that human M(IL-10) anti-inflammatory macrophages, present in TB-associated microenvironment, produce high levels of HIV-1. In vivo, M(IL-10) macrophages are expanded in lungs of co-infected non-human primates, which correlates with disease severity. Furthermore, HIV-1/Mtb co-infected patients display an accumulation of M(IL-10) macrophage markers (soluble CD163 and MerTK). These M(IL-10) macrophages form direct cell-to-cell bridges, which we identified as tunneling nanotubes (TNTs) involved in viral transfer. TNT formation requires the IL-10/STAT3 signaling pathway, and targeted inhibition of TNTs substantially reduces the enhancement of HIV-1 cell-to-cell transfer and overproduction in M(IL-10) macrophages. Our study reveals that TNTs facilitate viral transfer and amplification, thereby promoting TNT formation as a mechanism to be explored in TB/AIDS potential therapeutics.

PD-1/PD-L1 Pathway Modulates Macrophage Susceptibility to Mycobacterium tuberculosis Specific CD8+ T cell Induced Death.

CD8+T cells contribute to tuberculosis (TB) infection control by inducing death of infected macrophages. Mycobacterium tuberculosis (Mtb) infection is associated with increased PD-1/PD-L1 expression and alternative activation of macrophages. We aimed to study the role of PD-1 pathway and macrophage polarization on Mtb-specific CD8+T cell-induced macrophage death. We observed that both PD-L1 on CD14+ cells and PD-1 on CD8+T cells were highly expressed at the site of infection in pleurisy TB patients' effusion samples (PEMC). Moreover, a significant increase in CD8+T cells' Mtb-specific degranulation from TB-PEMC vs. TB-PBMC was observed, which correlated with PD-1 and PDL-1 expression. In an in vitro model, M1 macrophages were more susceptible to Mtb-specific CD8+T cells' cytotoxicity compared to M2a macrophages and involved the transfer of cytolytic effector molecules from CD8+T lymphocytes to target cells. Additionally, PD-L1 blocking significantly increased the in vitro Ag-specific CD8+T cell cytotoxicity against IFN-γ-activated macrophages but had no effect over cytotoxicity on IL-4 or IL-10-activated macrophages. Interestingly, PD-L1 blocking enhanced Mtb-specific CD8+ T cell killing of CD14+ cells from human tuberculous pleural effusion samples. Our data indicate that PD-1/PD-L1 pathway modulates antigen-specific cytotoxicity against M1 targets in-vitro and encourage the exploration of checkpoint blockade as new adjuvant for TB therapies.

Formation of Foamy Macrophages by Tuberculous Pleural Effusions Is Triggered by the Interleukin-10/Signal Transducer and Activator of Transcription 3 Axis through ACAT Upregulation.

The ability of Mycobacterium tuberculosis (Mtb) to persist in its human host relies on numerous immune evasion strategies, such as the deregulation of the lipid metabolism leading to the formation of foamy macrophages (FM). Yet, the specific host factors leading to the foamy phenotype of Mtb-infected macrophages remain unknown. Herein, we aimed to address whether host cytokines contribute to FM formation in the context of Mtb infection. Our approach is based on the use of an acellular fraction of tuberculous pleural effusions (TB-PE) as a physiological source of local factors released during Mtb infection. We found that TB-PE induced FM differentiation as observed by the increase in lipid bodies, intracellular cholesterol, and expression of the scavenger receptor CD36, as well as the enzyme acyl CoA:cholesterol acyl transferase (ACAT). Importantly, interleukin-10 (IL-10) depletion from TB-PE prevented the augmentation of all these parameters. Moreover, we observed a positive correlation between the levels of IL-10 and the number of lipid-laden CD14+ cells among the pleural cells in TB patients, demonstrating that FM differentiation occurs within the pleural environment. Downstream of IL-10 signaling, we noticed that the transcription factor signal transducer and activator of transcription 3 was activated by TB-PE, and its chemical inhibition prevented the accumulation of lipid bodies and ACAT expression in macrophages. In terms of the host immune response, TB-PE-treated macrophages displayed immunosuppressive properties and bore higher bacillary loads. Finally, we confirmed our results using bone marrow-derived macrophage from IL-10-/- mice demonstrating that IL-10 deficiency partially prevented foamy phenotype induction after Mtb lipids exposure. In conclusion, our results evidence a role of IL-10 in promoting the differentiation of FM in the context of Mtb infection, contributing to our understanding of how alterations of the host metabolic factors may favor pathogen persistence.

Tuberculosis is associated with expansion of a motile, permissive and immunomodulatory CD16(+) monocyte population via the IL-10/STAT3 axis.

The human CD14(+) monocyte compartment is composed by two subsets based on CD16 expression. We previously reported that this compartment is perturbed in tuberculosis (TB) patients, as reflected by the expansion of CD16(+) monocytes along with disease severity. Whether this unbalance is beneficial or detrimental to host defense remains to be elucidated. Here in the context of active TB, we demonstrate that human monocytes are predisposed to differentiate towards an anti-inflammatory (M2-like) macrophage activation program characterized by the CD16(+)CD163(+)MerTK(+)pSTAT3(+) phenotype and functional properties such as enhanced protease-dependent motility, pathogen permissivity and immunomodulation. This process is dependent on STAT3 activation, and loss-of-function experiments point towards a detrimental role in host defense against TB. Importantly, we provide a critical correlation between the abundance of the CD16(+)CD163(+)MerTK(+)pSTAT3(+) cells and the progression of the disease either at the local level in a non-human primate tuberculous granuloma context, or at the systemic level through the detection of the soluble form of CD163 in human sera. Collectively, this study argues for the pathogenic role of the CD16(+)CD163(+)MerTK(+)pSTAT3(+) monocyte-to-macrophage differentiation program and its potential as a target for TB therapy, and promotes the detection of circulating CD163 as a potential biomarker for disease progression and monitoring of treatment efficacy.

Human pleural B-cells regulate IFN-γ production by local T-cells and NK cells in a Mycobacterium tuberculosis-induced delayed hypersensitivity reaction.

DTH (delayed type hypersensitivity) reactions are secondary cellular immune responses that appear 24-72 h after antigen exposure. Tuberculous pleurisy is a common manifestation of extrapulmonary TB (tuberculosis) and is considered a human model of Th1-mediated DTH. In order to identify functional cross-talk among cellular populations sited in this inflammatory microenvironment, we analysed phenotypic and functional features of human B-cells isolated from the PF (pleural fluid) of TB patients. Freshly isolated PF-B-cells displayed a lower expression of CD20, CD1d and HLA-DR, and a higher expression of CD95, CD38, CD25, CXCR3 (CXC chemokine receptor 3) and CXCR4 (CXC chemokine receptor 4) than their PB (peripheral blood) counterparts, suggesting a non-classical in situ activation. Although memory PF-T-cell frequencies were increased, the frequencies of memory PF-B-cells were not. We demonstrated that, upon stimulation with γ-irradiated M. tuberculosis, mycobacterially secreted proteins or a lectin mitogen, PF-B-cells had a strong activation and produced IL-10 by a mechanism that was dependent on bystander activation of CD19(-) PF cells. Besides, within PF cells, B-cells diminished in vitro M. tuberculosis-induced IFN (interferon)-γ production by T-cells and NK (natural killer) cells in an IL-10-dependent manner. Finally, we found that the lower the frequency of B-cells, the higher the ratio of IFN-γ/IL-10 within PF. Thus our results suggest that B-cells can regulate a human DTH reaction induced by M. tuberculosis.

[Tuberculosis treatment. A practical guide elaborated by the tuberculosis section, Argentine Association of Respiratory Medicine]. / Tratamiento de la tuberculosis. Guia practica elaborada por la seccion tuberculosis, Asociacion Argentina de Medicina Respiratoria.

Tuberculosis is a worldwide prevalent disease. The emergence of multidrug-resistant strains spurred the search for new drugs. There are several tuberculosis treatment guidelines, international and local in a programmatic approach. An Argentinean specialists panel draw practical guidelines based in clinical criteria and the local and international bibliography through consensus meetings, including issues as: antituberculosis drugs available in Argentina, initial and re-treatement modalities, special situations treatment, adverse reactions to antituberculosis drugs, current indications of surgical treatment and new drugs under study for the treatment of the disease.

Tratamiento de la tuberculosis: guia practica elaborada por la Seccion Tuberculosis, Asociacion Argentina de Medicina Respiratoria / Tuberculosis treatment: a practical guide elaborated by the Tuberculosis Section, Argentine Association of Respiratory Medicine

La tuberculosis es una enfermedad prevalente en todo el mundo. La emergencia de cepas multirresistentes del Mycobacterium tuberculosis ha incentivado la búsqueda de nuevos fármacos. Existen diversas guías de tratamiento de la enfermedad, internacionales y a nivel programático local. Un grupo de especialistas argentinos elaboró una guía práctica basada en criterios clínicos y en la bibliografía nacional e internacional sobre el tema a través de reuniones de consenso, abarcando tópicos como: fármacos antituberculosos disponibles en la Argentina, modalidades de tratamiento inicial y retratamiento, tratamiento en situaciones especiales, reacciones adversas a fármacos antituberculosos, indicaciones actuales de tratamiento quirúrgico y nuevos fármacos en estudio para el tratamiento de la enfermedad.

Tuberculosis is a worldwide prevalent disease. The emergence of multidrug-resistant strains spurred the search for new drugs. There are several tuberculosis treatment guidelines, international and local in a programmatic approach. An Argentinean specialists panel draw practical guidelines based in clinical criteria and the local and international bibliography through consensus meetings, including issues as: antituberculosis drugs available in Argentina, initial and re-treatement modalities, special situations treatment, adverse reactions to antituberculosis drugs, current indications of surgical treatment and new drugs under study for the treatment of the disease.

Tratamiento de la tuberculosis: guia practica elaborada por la Seccion Tuberculosis, Asociacion Argentina de Medicina Respiratoria / Tuberculosis treatment: a practical guide elaborated by the Tuberculosis Section, Argentine Association of Respiratory Medicine

La tuberculosis es una enfermedad prevalente en todo el mundo. La emergencia de cepas multirresistentes del Mycobacterium tuberculosis ha incentivado la búsqueda de nuevos fármacos. Existen diversas guías de tratamiento de la enfermedad, internacionales y a nivel programático local. Un grupo de especialistas argentinos elaboró una guía práctica basada en criterios clínicos y en la bibliografía nacional e internacional sobre el tema a través de reuniones de consenso, abarcando tópicos como: fármacos antituberculosos disponibles en la Argentina, modalidades de tratamiento inicial y retratamiento, tratamiento en situaciones especiales, reacciones adversas a fármacos antituberculosos, indicaciones actuales de tratamiento quirúrgico y nuevos fármacos en estudio para el tratamiento de la enfermedad.(AU)

Tuberculosis is a worldwide prevalent disease. The emergence of multidrug-resistant strains spurred the search for new drugs. There are several tuberculosis treatment guidelines, international and local in a programmatic approach. An Argentinean specialists panel draw practical guidelines based in clinical criteria and the local and international bibliography through consensus meetings, including issues as: antituberculosis drugs available in Argentina, initial and re-treatement modalities, special situations treatment, adverse reactions to antituberculosis drugs, current indications of surgical treatment and new drugs under study for the treatment of the disease.(AU)

Tuberculosis polirresistente: su tratamiento quirúrgico / Polyresistant tuberculosis: its surgical treatment

Se presentan 36 casos de enfermos con TBC pulmonar que resultaron por distintas razones, excluída la infección por HIV, multiresistentes a drogas antituberculosas. Los mismos debieron ser sometidos a algún tipo de tratamiento quirúrgico, en la mayoría de los casos con adyuvancia quimioterápica. En 27 casos los pacientes fueron dados de alta curados. En 4, el tratamiento no dio resultados y 4 fallecieron entre los 2 y 3 años por progresión lesional y uno por paro cardíaco intraoperatorio. Se hacen consideraciones sobre la etiología y epidemiología de la resistencia bacteriana y su vinculación con HIV. Se describen las tácticas y técnicas de las distintas operaciones usadas en los casos que tratamos, incluyendo los tratamientos médicos con los que culminaron el postoperatorio. Se hace notar la mejor evolución de las resecciones pulmonares sobre los tratamientos colapsantes primarios.

Tuberculosis polirresistente: su tratamiento quirúrgico / Polyresistant tuberculosis: its surgical treatment

Se presentan 36 casos de enfermos con TBC pulmonar que resultaron por distintas razones, excluída la infección por HIV, multiresistentes a drogas antituberculosas. Los mismos debieron ser sometidos a algún tipo de tratamiento quirúrgico, en la mayoría de los casos con adyuvancia quimioterápica. En 27 casos los pacientes fueron dados de alta curados. En 4, el tratamiento no dio resultados y 4 fallecieron entre los 2 y 3 años por progresión lesional y uno por paro cardíaco intraoperatorio. Se hacen consideraciones sobre la etiología y epidemiología de la resistencia bacteriana y su vinculación con HIV. Se describen las tácticas y técnicas de las distintas operaciones usadas en los casos que tratamos, incluyendo los tratamientos médicos con los que culminaron el postoperatorio. Se hace notar la mejor evolución de las resecciones pulmonares sobre los tratamientos colapsantes primarios. (AU)