Rationale: Tuberculosis kills more than 1.5 million people per year, and standard treatment has remained unchanged for more than 30 years. Tuberculosis (TB) drives matrix metalloproteinase (MMP) activity to cause immunopathology. In advanced HIV infection, tissue destruction is reduced, but underlying mechanisms are poorly defined and no current antituberculous therapy reduces host tissue damage. Objectives: To investigate MMP activity in patients with TB with and without HIV coinfection and to determine the potential of doxycycline to inhibit MMPs and decrease pathology. Methods: Concentrations of MMPs and cytokines were analyzed by Luminex array in a prospectively recruited cohort of patients. Modulation of MMP secretion and Mycobacterium tuberculosis growth by doxycycline was studied in primary human cells and TB-infected guinea pigs. Measurements and Main Results: HIV coinfection decreased MMP concentrations in induced sputum of patients with TB. MMPs correlated with clinical markers of tissue damage, further implicating dysregulated protease activity in TB-driven pathology. In contrast, cytokine concentrations were no different. Doxycycline, a licensed MMP inhibitor, suppressed TB-dependent MMP-1 and -9 secretion from primary human macrophages and epithelial cells by inhibiting promoter activation. In the guinea pig model, doxycycline reduced lung TB colony forming units after 8 weeks in a dose-dependent manner compared with untreated animals, and in vitro doxycycline inhibited mycobacterial proliferation. Conclusions: HIV coinfection in patients with TB reduces concentrations of immunopathogenic MMPs. Doxycycline decreases MMP activity in a cellular model and suppresses mycobacterial growth in vitro and in guinea pigs. Adjunctive doxycycline therapy may reduce morbidity and mortality in TB.Keywords: lung; mycobacteria; immunopathology; protease inhibitors Tuberculosis (TB) continues to kill more than 1.5 million people a year (1). Standard treatment for TB has remained unchanged for more than 30 years (2), and multidrug-and extensively drugresistant strains are progressively emerging (3, 4). Mortality rates remain high among patients even after they have commenced TB treatment (5, 6). A characteristic hallmark of TB is tissue destruction, causing morbidity, mortality, and transmission of infection. However, the mediators of this immunopathology are incompletely understood (7,8), preventing the design of rational therapies to reduce immunemediated host damage and improve outcomes in TB.TB is primarily a disease of the lung (9, 10). In advanced HIV infection, with severely reduced CD4 cell counts, TB infection is common, but there is reduced tissue destruction and cavitation rarely occurs (11). The underlying cause of divergent pathology in HIV-TB coinfection is poorly defined, and greater understanding of this tissue destruction may identify novel therapeutic approaches to limit morbidity and mortality. The biochemistry of the lung extracellular matrix predicts that matrix metalloproteinases (MMPs) will be ...
Tuberculosis (TB) is characterized by extensive pulmonary matrix breakdown. Interleukin‐17 (IL‐17) is key in host defence in TB but its role in TB‐driven tissue damage is unknown. We investigated the hypothesis that respiratory stromal cell matrix metalloproteinase (MMP) production in TB is regulated by T‐helper 17 (TH‐17) cytokines. Biopsies of patients with pulmonary TB were analysed by immunohistochemistry (IHC), and patient bronchoalveolar lavage fluid (BALF) MMP and cytokine concentrations were measured by Luminex assays. Primary human airway epithelial cells were stimulated with conditioned medium from human monocytes infected with Mycobacterium tuberculosis (Mtb) and TH‐17 cytokines. MMP secretion, activity, and gene expression were determined by ELISA, Luminex assay, zymography, RT‐qPCR, and dual luciferase reporter assays. Signalling pathways were examined using phospho‐western analysis and siRNA. IL‐17 is expressed in TB patient granulomas and MMP‐3 is expressed in adjacent pulmonary epithelial cells. IL‐17 had a divergent, concentration‐dependent effect on MMP secretion, increasing epithelial secretion of MMP‐3 (p < 0.001) over 72 h, whilst decreasing that of MMP‐9 (p < 0.0001); mRNA levels were similarly affected. Both IL‐17 and IL‐22 increased fibroblast Mtb‐dependent MMP‐3 secretion but IL‐22 did not modulate epithelial MMP‐3 expression. Both IL‐17 and IL‐22, but not IL‐23, were significantly up‐regulated in BALF from TB patients. IL‐17‐driven MMP‐3 was dependent on p38 MAP kinase and the PI3K p110α subunit. In summary, IL‐17 drives airway stromal cell‐derived MMP‐3, a mediator of tissue destruction in TB, alone and with monocyte‐dependent networks in TB. This is regulated by p38 MAP kinase and PI3K pathways. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Plasmodium merozoite surface protein-1 (MSP-1) is an essential antigen for the merozoite invasion of erythrocytes. A key challenge to the development of an effective malaria vaccine that can block the erythrocyte invasion is to establish the molecular interaction(s) among the parasite surface proteins as well as with the host cell encoded receptors. In the present study, we applied molecular interactions and proteome approaches to identify PfMSP-1 associated complex on the merozoite surface. Proteomic analysis identified a major malaria surface protein, PfRhopH3 interacting with PfMSP-1(42). Pull-down experiments with merozoite lysate using anti-PfMSP-1 or anti-PfRhopH3 antibodies showed 16 bands that when identified by tandem mass spectrometry corresponded to11 parasite proteins: PfMSP-3, PfMSP-6, PfMSP-7, PfMSP-9, PfRhopH3, PfRhopH1, PfRAP-1, PfRAP-2, and two RAP domain containing proteins. This MSP-1 associated complex was specifically seen at schizont/merozoite stages but not the next ring stage. We could also identify many of these proteins in culture supernatant, suggesting the shedding of the complex. Interestingly, the PfRhopH3 protein also showed binding to the human erythrocyte and anti-PfRhopH3 antibodies blocked the erythrocyte invasion of the merozoites. These results have potential implications in the development of PfMSP-1 based blood stage malaria vaccine.
dTuberculosis is characterized by extensive destruction and remodelling of the pulmonary extracellular matrix. Stromal cell-derived matrix metalloproteinases (MMPs) are implicated in this process and may be a target for adjunctive immunotherapy. We hypothesized that MMPs are elevated in bronchoalveolar lavage fluid of tuberculosis patients and that antimycobacterial agents may have a modulatory effect on MMP secretion. Concentrations of MMP-1, -2, -3, -7, -8, and -9 were elevated in the bronchoalveolar lavage fluid from tuberculosis patients compared to those in bronchoalveolar lavage fluid from patients with other pulmonary conditions. There was a positive correlation between MMP-3, MMP-7, and MMP-8 and a chest radiological score of cavitation and parenchymal damage. Respiratory epithelial cell-derived MMP-3 was suppressed by moxifloxacin, rifampicin, and azithromycin in a dose-dependent manner. Respiratory epithelial cell-derived MMP-1 was suppressed by moxifloxacin and azithromycin, whereas MMP-9 secretion was only decreased by moxifloxacin. In contrast, moxifloxacin and azithromycin both increased MMP-1 and -3 secretion from MRC-5 fibroblasts, demonstrating that the effects of these drugs are cell specific. Isoniazid did not affect MMP secretion. In conclusion, MMPs are elevated in bronchoalveolar lavage fluid from tuberculosis patients and correlate with parameters of tissue destruction. Antimycobacterial agents have a hitherto-undescribed immunomodulatory effect on MMP release by stromal cells.
This study was designed to investigate the role of the phosphatidyl inositol 3-kinase (PI3K)/AKT/p70(S6K) signaling path on regulation of primary normal human bronchial epithelial cell-derived matrix metalloproteinase (MMP)-1, -3, and -9 expression in tuberculosis (TB). These MMPs are key in pathological extracellular matrix degradation in TB. Normal human bronchial epithelials were stimulated with conditioned medium from monocytes infected with virulent TB (CoMTb) and components of the PI3K/AKT signaling pathway blocked using specific chemical inhibitors and siRNA. MMP gene expression was measured by RT-PCR and secretion by ELISA, luminex, or zymography. Phospho-p70 S6K was detected by Western blot analysis and activity blocked by rapamycin. Chemical blockade of the proximal catalytic PI3K p110 subunit augmented MMP-1 and MMP-9 in a dose-dependent manner (all P<0.001) but suppressed MMP-3 (P<0.01). Targeted siRNA studies identified the p110α isoform as key causing 5-fold increase in TB network-dependent MMP-1 secretion to 4900 ± 1100 pg/ml. Specific inhibition of the AKT node suppressed all 3 MMPs. Phospho-p70(S6K) was identified in the cellular model, and rapamycin, a p70(S6K) inhibitor, inhibited MMP-1 (P<0.001) and MMP-3 (P<0.01) but not MMP-9. Controls were epithelial cells that were unstimulated or exposed to conditioned medium from monocytes not exposed to TB. In summary, blockade of the proximal PI3K catalytic subunit increases MMP-1 and MMP-9, whereas rapamycin decreased both MMP-1 and MMP-3. The regulation of the PI3K path in TB is complex, MMP specific, and a potential immunotherapeutic target in diseases characterized by tissue destruction.
To evaluate the performance of the Pediatric Index of Mortality 3 as mortality risk assessment model. DESIGN:This prospective study included all admissions 30 days to 18 years old for 12 months during 2016 and 2017. Data gathered included the following: age and gender, diagnosis and reason for PICU admission, data specific for the Pediatric Index of Mortality 3 calculation, PICU outcomes (death or survival), and length of PICU stay.SETTING: Nine units that care for children within tertiary or quaternary academic hospitals in South Africa. PATIENTS:All admissions 30 days to 18 years old, excluding premature infants, children who died within 2 hours of admission, or children transferred to other PICUs, and those older than 18 years old. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS:There were 3,681 admissions of which 2,253 (61.3%) were male. The median age was 18 months (interquartile range, 6-59.5 mo). There were 354 deaths (9.6%). The Pediatric Index of Mortality 3 predicted 277.47 deaths (7.5%). The overall standardized mortality ratio was 1.28. The area under the receiver operating characteristic curve was 0.81 (95% CI 0.79-0.83). The Hosmer-Lemeshow goodness-of-fit test statistic was 174.4 (p < 0.001). Standardized mortality ratio for all age groups was greater than 1. Standardized mortality ratio for diagnostic subgroups was mostly greater than 1 except for those whose reason for PICU admission was classified as accident, toxin and envenomation, and metabolic which had an standardized mortality ratio less than 1. There were similar proportions of respiratory patients, but significantly greater proportions of neurologic and cardiac (including postoperative) patients in the Pediatric Index of Mortality 3 derivation cohort than the South African cohort. In contrast, the South African cohort contained a significantly greater proportion of miscellaneous (including injury/accident victims) and postoperative noncardiac patients. CONCLUSIONS:The Pediatric Index of Mortality 3 discrimination between death and survival among South African units was good. Case-mix differences between these units and the Pediatric Index of Mortality 3 derivation cohort may partly explain the poor calibration. We need to recalibrate Pediatric Index of Mortality 3 to the local setting.
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