RESUMEN
N-Methylmesoporphyrin IX (NMM) has long been known as a G-quadruplex DNA (G4) ligand. However, there has been little investigation into its G-quadruplex photocleavage activity. Herein, we demonstrate that NMM is a highly selective photocleavage agent for G4 structures but not duplex DNA. Analysis of the cleavage products by PAGE demonstrates that G4 photocleavage by NMM occurs at sites similar to those cleaved by TMPyP4, a nonselective DNA photocleavage agent. Although NMM is shown here to generate singlet oxygen in the presence of both duplex and G4, the lack of increased photocleavage in D2 O indicated that singlet oxygen is not involved in the photocleavage of G4 by NMM.
Asunto(s)
ADN/química , Mesoporfirinas/química , G-Cuádruplex , Estructura Molecular , Procesos FotoquímicosRESUMEN
Chronic immune activation promotes tuberculosis (TB) reactivation in the macaque Mycobacterium tuberculosis (M. tuberculosis)/SIV coinfection model. Initiating combinatorial antiretroviral therapy (cART) early lowers the risk of TB reactivation, but immune activation persists. Studies of host-directed therapeutics (HDTs) that mitigate immune activation are, therefore, required. Indoleamine 2,3, dioxygenase (IDO), a potent immunosuppressor, is one of the most abundantly induced proteins in NHP and human TB granulomas. Inhibition of IDO improves immune responses in the lung, leading to better control of TB, including adjunctive to TB chemotherapy. The IDO inhibitor D-1 methyl tryptophan (D1MT) is, therefore, a bona fide TB HDT candidate. Since HDTs against TB are likely to be deployed in an HIV coinfection setting, we studied the effect of IDO inhibition in M. tuberculosis/SIV coinfection, adjunctive to cART. D1MT is safe in this setting, does not interfere with viral suppression, and improves the quality of CD4+ and CD8+ T cell responses, including reconstitution, activation and M. tuberculosis-specific cytokine production, and access of CD8+ T cells to the lung granulomas; it reduces granuloma size and necrosis, type I IFN expression, and the recruitment of inflammatory IDO+ interstitial macrophages (IMs). Thus, trials evaluating the potential of IDO inhibition as HDT in the setting of cART in M. tuberculosis/HIV coinfected individuals are warranted.
Asunto(s)
Coinfección , Indolamina-Pirrol 2,3,-Dioxigenasa , Macaca mulatta , Mycobacterium tuberculosis , Síndrome de Inmunodeficiencia Adquirida del Simio , Triptófano , Indolamina-Pirrol 2,3,-Dioxigenasa/antagonistas & inhibidores , Indolamina-Pirrol 2,3,-Dioxigenasa/metabolismo , Animales , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/tratamiento farmacológico , Coinfección/tratamiento farmacológico , Coinfección/inmunología , Triptófano/metabolismo , Triptófano/análogos & derivados , Tuberculosis/inmunología , Tuberculosis/tratamiento farmacológico , Virus de la Inmunodeficiencia de los Simios/inmunología , Modelos Animales de Enfermedad , Linfocitos T CD8-positivos/inmunología , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/inmunología , Infecciones por VIH/complicaciones , Antirretrovirales/uso terapéutico , Antirretrovirales/farmacología , Masculino , Pulmón/inmunología , Pulmón/patología , Humanos , Linfocitos T CD4-Positivos/inmunologíaRESUMEN
The expression of indoleamine 2,3-dioxygenase (IDO), a robust immunosuppressant, is significantly induced in macaque tuberculosis (TB) granulomas, where it is expressed on IFN-responsive macrophages and myeloid-derived suppressor cells. IDO expression is also highly induced in human TB granulomas, and products of its activity are detected in patients with TB. In vivo blockade of IDO activity resulted in the reorganization of the granuloma with substantially greater T cells being recruited to the core of the lesions. This correlated with better immune control of TB and reduced lung M. tuberculosis burdens. To study if the IDO blockade strategy can be translated to a bona fide host-directed therapy in the clinical setting of TB, we studied the effect of IDO inhibitor 1-methyl-d-tryptophan adjunctive to suboptimal anti-TB chemotherapy. While two-thirds of controls and one-third of chemotherapy-treated animals progressed to active TB, inhibition of IDO adjunctive to the same therapy protected macaques from TB, as measured by clinical, radiological, and microbiological attributes. Although chemotherapy improved proliferative T cell responses, adjunctive inhibition of IDO further enhanced the recruitment of effector T cells to the lung. These results strongly suggest the possibility that IDO inhibition can be attempted adjunctive to anti-TB chemotherapy in clinical trials.
Asunto(s)
Mycobacterium tuberculosis , Tuberculosis Pulmonar , Tuberculosis , Animales , Humanos , Granuloma , Indolamina-Pirrol 2,3,-Dioxigenasa , Macrófagos/metabolismo , Mycobacterium tuberculosis/metabolismoRESUMEN
With the advent of the novel SARS-CoV-2, the entire world has been thrown into chaos with severe disruptions from a normal life. While the entire world was going chaotic, the researchers throughout the world were struggling to contribute to the best of their capabilities to advance the understanding of this new pandemic and fast track the development of novel therapeutics and vaccines. While various animal models have helped a lot to understand the basic physiology, nonhman primates have been promising and much more successful in modelling human diseases compared to other available clinical models. Here we describe the different aspects of modelling the SARS-CoV-2 infection in NHPs along with the associated methods used in NHP immunology.
Asunto(s)
COVID-19 , Animales , Modelos Animales de Enfermedad , Pandemias , Primates , SARS-CoV-2RESUMEN
Studies using the nonhuman primate model of Mycobacterium tuberculosis/simian immunodeficiency virus coinfection have revealed protective CD4+ T cell-independent immune responses that suppress latent tuberculosis infection (LTBI) reactivation. In particular, chronic immune activation rather than the mere depletion of CD4+ T cells correlates with reactivation due to SIV coinfection. Here, we administered combinatorial antiretroviral therapy (cART) 2 weeks after SIV coinfection to study whether restoration of CD4+ T cell immunity occurred more broadly, and whether this prevented reactivation of LTBI compared to cART initiated 4 weeks after SIV. Earlier initiation of cART enhanced survival, led to better control of viral replication, and reduced immune activation in the periphery and lung vasculature, thereby reducing the rate of SIV-induced reactivation. We observed robust CD8+ T effector memory responses and significantly reduced macrophage turnover in the lung tissue. However, skewed CD4+ T effector memory responses persisted and new TB lesions formed after SIV coinfection. Thus, reactivation of LTBI is governed by very early events of SIV infection. Timing of cART is critical in mitigating chronic immune activation. The potential novelty of these findings mainly relates to the development of a robust animal model of human M. tuberculosis/HIV coinfection that allows the testing of underlying mechanisms.
Asunto(s)
Antirretrovirales/farmacología , Coinfección , Tuberculosis Latente/metabolismo , Mycobacterium tuberculosis/metabolismo , Síndrome de Inmunodeficiencia Adquirida del Simio , Virus de la Inmunodeficiencia de los Simios/metabolismo , Animales , Coinfección/tratamiento farmacológico , Coinfección/metabolismo , Coinfección/microbiología , Coinfección/virología , Macaca mulatta , Síndrome de Inmunodeficiencia Adquirida del Simio/tratamiento farmacológico , Síndrome de Inmunodeficiencia Adquirida del Simio/metabolismo , Síndrome de Inmunodeficiencia Adquirida del Simio/microbiologíaRESUMEN
Coronavirus disease 2019 (COVID-19) is a highly contagious, infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which emerged in late 2019 in Wuhan China. A year after the World Health Organization declared COVID-19 a global pandemic, over 215 million confirmed cases and approximately 5 million deaths have been reported worldwide. In this multidisciplinary review, we summarize important insights for COVID-19, ranging from its origin, pathology, epidemiology, to clinical manifestations and treatment. More importantly, we also highlight the foundational connection between genetics and the development of personalized medicine and how these aspects have an impact on disease treatment and management in the dynamic landscape of this pandemic.
Asunto(s)
COVID-19 , China/epidemiología , Humanos , Pandemias , SARS-CoV-2RESUMEN
The development of vaccines against infectious diseases has helped us battle the greatest threat to public health. With the emergence of novel viruses, targeted immunotherapeutics ranging from informed vaccine development to personalized medicine may be the very thing that separates us between life and death. Late in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of coronavirus disease 2019 (COVID-19), made a remarkable entrance to human civilization, being one of many to cross the species barrier. This review discusses the important aspects of COVID-19, providing a brief overview of our current understanding of dysregulated immune responses developed using various experimental models, a brief outline of experimental models of COVID-19 and more importantly, the rapid development of vaccines against COVID-19.
Asunto(s)
Vacunas contra la COVID-19/inmunología , COVID-19/patología , COVID-19/prevención & control , SARS-CoV-2/inmunología , Inmunidad Adaptativa/inmunología , Animales , COVID-19/terapia , Síndrome de Liberación de Citoquinas/patología , Citocinas/biosíntesis , Citocinas/inmunología , Modelos Animales de Enfermedad , Humanos , Inmunoterapia/métodos , Células Mieloides/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Vacunación , Desarrollo de VacunasRESUMEN
Myeloid-derived suppressor cells (MDSCs) represent an innate immune cell population comprised of immature myeloid cells and myeloid progenitors with very potent immunosuppressive potential. MDSCs are reported to be abundant in the lungs of active tuberculosis (TB) patients. We sought to perform an in-depth study of MDSCs during latent TB infection (LTBI) and active TB (ATB) using the nonhuman primate (NHP) model of pulmonary TB. We found a higher proportion of granulocytic, polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) in the lungs of ATB animals compared to those with LTBI or naive control animals. Active disease in the lung, but not LTBI, was furthermore associated with higher proliferation, expansion, and immunosuppressive capabilities of PMN-MDSCs, as shown by enhanced expression of Ki67, indoleamine 2,3-dioxygenase (IDO1), interleukin-10 (IL-10), matrix metallopeptidase 9 (MMP-9), inducible nitric oxide synthase (iNOS), and programmed death-ligand 1 (PD-L1). These immunosuppressive PMN-MDSCs specifically localized to the lymphocytic cuff at the periphery of the granulomas in animals with ATB. Conversely, these cells were scarcely distributed in interstitial lung tissue and the inner core of granulomas. This spatial regulation suggests an important immunomodulatory role of PMN-MDSCs by restricting T cell access to the TB granuloma core and can potentially explain dysfunctional anti-TB responses in active granuloma. Our results raise the possibility that the presence of MDSCs can serve as a biomarker for ATB, while their disappearance can indicate successful therapy. Furthermore, MDSCs may serve as a potential target cell for adjunctive TB therapy. IMPORTANCE Myeloid cells are immunocytes of innate origin that orchestrate the first response toward pathogens via immune surveillance (uptake and killing), antigen presentation, and initiation of adaptive immunity by T cell stimulation. However, MDSCs are a subset of innate immunocytes that deviate to an immunoregulatory phenotype. MDSCs possess strong immunosuppressive capabilities that are induced in autoimmune, malignant neoplastic, and chronic inflammatory diseases. Induction of MDSCs has been found in peripheral blood, bronchoalveolar lavage (BAL) fluid, and pleural effusions of active TB patients, but their precise localization in lung tissue and in TB granulomas remains unclear due to challenges associated with sampling lungs and granulomas from active TB patients. Nonhuman primates (NHPs) are an important animal model with TB granulomas that closely mimic those found in humans and can therefore be used for studies that are otherwise challenging with patient material. Herein, we study MDSC localization in the lungs of NHPs exhibiting latent and active TB. Our findings reveal that MDSCs localize and exert their immunosuppressive roles at the periphery rather than in the core of TB granulomas.
Asunto(s)
Granuloma/inmunología , Tuberculosis Latente/inmunología , Células Supresoras de Origen Mieloide/inmunología , Linfocitos T/inmunología , Tuberculosis Pulmonar/inmunología , Animales , Antígeno B7-H1/genética , Antígeno B7-H1/inmunología , Modelos Animales de Enfermedad , Femenino , Granuloma/microbiología , Humanos , Indolamina-Pirrol 2,3,-Dioxigenasa/genética , Indolamina-Pirrol 2,3,-Dioxigenasa/inmunología , Interleucina-10/genética , Interleucina-10/inmunología , Tuberculosis Latente/genética , Tuberculosis Latente/microbiología , Macaca mulatta , Metaloproteinasa 9 de la Matriz/genética , Metaloproteinasa 9 de la Matriz/inmunología , Mycobacterium tuberculosis/fisiología , Tuberculosis Pulmonar/genética , Tuberculosis Pulmonar/microbiologíaRESUMEN
Non-human primate models will expedite therapeutics and vaccines for coronavirus disease 2019 (COVID-19) to clinical trials. Here, we compare acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in young and old rhesus macaques, baboons and old marmosets. Macaques had clinical signs of viral infection, mild to moderate pneumonitis and extra-pulmonary pathologies, and both age groups recovered in two weeks. Baboons had prolonged viral RNA shedding and substantially more lung inflammation compared with macaques. Inflammation in bronchoalveolar lavage was increased in old versus young baboons. Using techniques including computed tomography imaging, immunophenotyping, and alveolar/peripheral cytokine response and immunohistochemical analyses, we delineated cellular immune responses to SARS-CoV-2 infection in macaque and baboon lungs, including innate and adaptive immune cells and a prominent type-I interferon response. Macaques developed T-cell memory phenotypes/responses and bystander cytokine production. Old macaques had lower titres of SARS-CoV-2-specific IgG antibody levels compared with young macaques. Acute respiratory distress in macaques and baboons recapitulates the progression of COVID-19 in humans, making them suitable as models to test vaccines and therapies.