Occurrence of matrix metalloproteinases and tissue inhibitors of metalloproteinases in tuberculous pleuritis

Immunological aspects of host-pathogen crosstalk in the co-pathogenesis of diabetes and latent tuberculosis

Introduction

Diabetes is a potent risk factor for the activation of latent tuberculosis and worsens the tuberculosis (TB) treatment outcome. The major reason for mortality and morbidity in diabetic patients is due to their increased susceptibility to TB. Thus, the study was conducted to understand the crosstalk between M. tuberculosis and its host upon latent tuberculosis infection and under hyperglycemic conditions or diabetes.

Methods

An animal model was employed to study the relationship between latent tuberculosis and diabetes. BCG immunization was done in mice before infection with M. tuberculosis, and latency was confirmed by bacillary load, histopathological changes in the lungs and gene expression of hspX, tgs1, tgs3 and tgs5. Diabetes was then induced by a single high dose of streptozotocin (150 mg/kg body weight). Host factors, like various cytokines and MMPs (Matrix metalloproteinases), which play an important role in the containment of mycobacterial infection were studied in vivo and in vitro.

Results

A murine model of latent TB was developed, which was confirmed by CFU counts (<10⁴ in the lungs and spleen) and granuloma formation in lungs in the latent TB group. Also, the gene expression of hspX, tgs1, and tgs5 was upregulated, and after diabetes induction, blood glucose levels were >200 mg/dl. An in vitro study employing a THP-1 macrophage model of latent and active tuberculosis under normal and high glucose conditions showed that dormant bacilli were better contained in the presence of 5.5 mM glucose concentration as compared with active bacilli. However, the killing and restriction efficiency of macrophages decreased, and CFU counts increased significantly with an increase in glucose concentration.

Discussion

The decreased levels of MCP-1, decreased expression of mmp-9, and increased expression of mmp-1 in the latent group at high glucose concentrations could explain the failure of granuloma formation at high glucose conditions.

Helminth Coinfection Is Associated With Enhanced Plasma Levels of Matrix Metalloproteinases and Tissue Inhibitor of Metalloproteinases in Tuberculous Lymphadenitis

Matrix metalloproteinases (MMPs) are crucial for tissue remodeling and repair and are expressed in diverse infections, whereas tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of MMPs. However, the interaction of MMPs and TIMPs in tuberculous lymphadenitis (TBL), an extra-pulmonary form of tuberculosis (EPTB) and helminth (Hel+) coinfection is not known. Therefore, this present study investigates the levels of circulating MMPs (1, 2, 3, 7, 8, 9, 12, 13) and TIMPs (1, 2, 3, 4) in TBL individuals with helminth (Strongyloides stercoralis [Ss], hereafter Hel+) coinfection and without helminth coinfection (hereafter, Hel-). In addition, we have also carried out the regression analysis and calculated the MMP/TIMP ratios between the two study groups. We describe that the circulating levels of MMPs (except MMP-8 and MMP-12) were elevated in TBL-Hel+ coinfected individuals compared to TBL-Hel- individuals. Similarly, the systemic levels of TIMPs (1, 2, 3, 4) were increased in TBL-Hel+ compared to TBL-Hel- groups indicating that it is a feature of helminth coinfection per se. Finally, our multivariate analysis data also revealed that the changes in MMPs and TIMPs were independent of age, sex, and culture status between TBL-Hel+ and TBL-Hel- individuals. We show that the MMP-2 ratio with all TIMPs were significantly associated with TBL-helminth coinfection. Thus, our results describe how helminth infection has a profound effect on the pathogenesis of TBL and that both MMPs and TIMPs could dampen the immunity against the TBL-Hel+ coinfected individuals.

The Interplay Between Systemic Inflammation, Oxidative Stress, and Tissue Remodeling in Tuberculosis

Significance: Excessive and prolonged proinflammatory responses are associated with oxidative stress, which is commonly observed during chronic tuberculosis (TB). Such condition favors tissue destruction and consequently bacterial spread. A tissue remodeling program is also triggered in chronically inflamed sites, facilitating a wide spectrum of clinical manifestations. Recent Advances: Since persistent and exacerbated oxidative stress responses have been associated with severe pathology, a number of studies have suggested that the inhibition of this augmented stress response by improving host antioxidant status may represent a reasonable strategy to ameliorate tissue damage in TB. Critical Issues: This review summarizes the interplay between oxidative stress, systemic inflammation and tissue remodeling, and its consequences in promoting TB disease. We emphasize the most important mechanisms associated with stress responses that contribute to the progression of TB. We also point out important host immune components that may influence the exacerbation of cellular stress and the subsequent tissue injury. Future Directions: Further research should reveal valuable targets for host-directed therapy of TB, preventing development of severe immunopathology and disease progression. Antioxid. Redox Signal. 34, 471-485.

Matrix Metalloproteinases and Tissue Inhibitors of Metalloproteinases Are Potential Biomarkers of Pulmonary and Extra-Pulmonary Tuberculosis

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) are potential regulators of tuberculosis (TB) pathology. Whether they are candidates for non-sputum-based biomarkers for pulmonary TB (PTB) and extra-pulmonary TB (EPTB) is not fully understood. Hence, to examine the association of MMPs and TIMPs with PTB and EPTB, we have measured the circulating levels of MMPs (MMP-1, 2, 3, 7, 8, 9, 12, and 13) and TIMPs (TIMP-1, 2, 3, and 4) in PTB, EPTB and compared them with latent tuberculosis (LTB) or healthy control (HC) individuals. We have also assessed their circulating levels before and after the completion of anti-tuberculosis treatment (ATT). Our data describes that systemic levels of MMP-1, 8, 9, 12 were significantly increased in PTB compared to EPTB, LTB, and HC individuals. In contrast, MMP-7 was significantly reduced in PTB compared to EPTB individuals. Likewise, the systemic levels of MMP-1, 7, 13 were significantly increased in EPTB in comparison to LTB and HC individuals. In contrast, MMP-8 was significantly reduced in EPTB individuals compared to LTB and HC individuals. In addition, the systemic levels of TIMP-1, 2, 3 were significantly diminished and TIMP-4 levels were significantly enhanced in PTB compared to EPTB, LTB, and HC individuals. The circulating levels of TIMP-2 was significantly reduced and TIMP-3 was significantly elevated in EPTB individuals in comparison with LTB and HCs. Some of the MMPs (7, 8, 9, 12, 13 in PTB and 1, 7, 8, 9 in EPTB) and TIMPs (1, 2, 3, 4 in PTB and 4 in EPTB) were significantly modulated upon treatment completion. ROC analysis showed that MMP-1, 9 and TIMP-2, 4 could clearly discriminate PTB from EPTB, LTB and HCs and MMP-13 and TIMP-2 could clearly discriminate EPTB from LTB and HCs. Additionally, multivariate analysis also indicated that these alterations were independent of age and sex in PTB and EPTB individuals. Therefore, our data demonstrates that MMPs and TIMPs are potential candidates for non-sputum-based biomarkers for differentiating PTB and EPTB from LTB and HC individuals.

Plasma levels of C-reactive protein, matrix metalloproteinase-7 and lipopolysaccharide-binding protein distinguish active pulmonary or extrapulmonary tuberculosis from uninfected controls in children

The immune profile associated with distinct clinical forms of tuberculosis (TB) has been extensively described for adult populations. Nevertheless, studies describing immune determinants of pulmonary or extrapulmonary TB (PTB or EPTB, respectively) in children are scarce. Here, we retrospectively assessed plasma levels of several mediators of inflammation in age and sex-matched children from South India presenting with PTB (n = 14) or EPTB (n = 22) as well as uninfected healthy controls (n = 19) to identify biomarkers that could accurately distinguish different TB clinical forms. Furthermore, we performed exploratory analyses testing the influence of sex on the systemic inflammatory profile. The analyses identified a biosignature of 10 biomarkers capable of distinguishing the three clinical groups simultaneously. Machine-learning decision trees indicated that C-reactive protein (CRP), matrix metalloproteinase (MMP)-7 and lipopolysaccharide-binding protein (LBP) were the markers that, when combined, displayed the highest accuracy in identifying the clinical groups. Additional exploratory analyses suggested that the disease signatures were highly influenced by sex. Therefore, sex differentially impacted status of systemic inflammation, immune activation and tissue remodeling in children with distinct clinical forms of TB. Regardless of such nuances related to biological sex, MMP-7, CRP and LBP were strong discriminators of active TB and thus could be considered as biomarkers useful in discrimination different TB clinical forms. These observations have implications on our understanding of the immunopathology of both clinical forms of TB in pediatric patients. If validated by other studies in the future, the combination of identified biomarkers may help development of point-of-care diagnostic or prognostic tools.

Elevated levels of matrix metalloproteinases reflect severity and extent of disease in tuberculosis-diabetes co-morbidity and are predominantly reversed following standard anti-tuberculosis or metformin treatment

Background

Matrix metalloproteinases (MMPs) are considered to be key mediators of tuberculosis (TB) pathology but their role in tuberculosis – diabetes comorbidity (TB-DM) is not well understood.

Methods

To study the association of MMP levels with severity and extent of disease as well as bacterial burden in TB-DM, we examined the systemic levels of MMP-1, − 2, − 3, − 7, − 8, − 9, − 10, − 12 and − 13 in individuals with TB-DM and compared them to those with TB alone (TB) or healthy controls (HC).

Results

Circulating levels of MMP-1, − 2, − 3, − 7, − 10 and − 12 were significantly higher in TB-DM compared to both TB and HC and MMP -13 levels were higher in comparison to HC alone. To understand the effect of standard anti-tuberculosis therapy (ATT) on these MMP levels in TB-DM, we measured the levels of MMPs at the end of treatment (post-treatment). Our findings indicate that ATT is associated with a significant reduction in the levels of MMP-1, − 2, − 3, − 8 and − 13 post-treatment. Moreover, the levels of MMP-1, − 2, − 3, − 9 and − 12 were significantly higher in TB-DM individuals with cavitary disease and/or bilateral disease at baseline but not post-treatment. Similarly, the levels of MMP -1, − 2, − 3 and − 8 exhibited a significant positive relationship with bacterial burden and HbA1c levels at baseline but not post-treatment. Within the TB-DM group, those known to be diabetic before incident TB (KDM) exhibited significantly higher levels of MMP-1, − 2, − 10 and − 12 at baseline and of MMP-1 and -3 post-treatment compared to those newly diagnosed with DM (NDM). Finally, KDM individuals on metformin treatment exhibited significantly lower levels of MMP-1, − 2, − 3, − 7, − 9 and − 12 at baseline and of MMP-7 post-treatment.

Conclusions

Our data demonstrate that systemic MMP levels reflect baseline disease severity and extent in TB-DM, differentiate KDM from NDM and are modulated by ATT and metformin therapy.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3246-y) contains supplementary material, which is available to authorized users.

Calpain and spectrin breakdown products as potential biomarkers in tuberculous pleural effusion

Background

Early diagnosis of tuberculous pleural effusion (TPE) remains difficult. Calpain is a family of calcium-dependent endopeptidase that plays an important role in extracellular matrix (ECM) remodeling and collagen synthesis. The aim of this study was to explore the diagnostic value of pleural fluid angiotensin-converting enzyme (ACE), calpain-1, spectrin breakdown products (SBDP), and matrix metalloproteinase-1 (MMP-1) in TPE and malignant pleural effusion (MPE).

Methods

The study included 47 patients with TPE, 28 patients with MPE, and 10 patients with transudate of non-tuberculous and non-malignant origin as controls. Calpain-1, ACE, SBDP, and MMP-1 levels in pleural fluid were measured by the ELISA method.

Results

ACE, calpain-1, SBDP, and MMP-1 levels were higher in TPE than MPE and transudate (all, P<0.05). On multivariate logistic regression analysis, adenosine deaminase (ADA) ≥40 IU/mL, calpain-1 ≥787 ng/mL, and SBDP ≥2.745 ng/mL were independent factors associated with TPE. The predicted probability of TPE based on these three predictors had an area under the receiver operating characteristic (ROC) curve of 0.985, with 97.9% sensitivity and 86.6% specificity under a cut-off value of 0.326. In patients with TPE, residual pulmonary thickening (RPT) was associated with significantly higher calpain-1, SBDP, and MMP-1 levels (all, P<0.05) versus cases without RPT.

Conclusions

Our results suggest that the overproduction of calpain-1 and SBDP is associated with pleural fibrosis in tuberculous pleurisy. While ADA is a conventional marker for diagnostic TPE, the simultaneous measurement of calpain-1 and SBDP l in pleural fluid may improve the diagnostic efficacy.

Hemostatic Changes Associated With Increased Mortality Rates in Hospitalized Patients With HIV-Associated Tuberculosis: A Prospective Cohort Study

Background

Mortality rates remain high for human immunodeficiency virus (HIV)-associated tuberculosis, and our knowledge of contributing mechanisms is limited. We aimed to determine whether hemostatic changes in HIV-tuberculosis were associated with mortality or decreased survival time and the contribution of mycobacteremia to these effects.

Methods

We conducted a prospective study in Khayelitsha, South Africa, in hospitalized HIV-infected patients with CD4 cell counts <350/µL and microbiologically proved tuberculosis. HIV-infected outpatients without tuberculosis served as controls. Plasma biomarkers reflecting activation of procoagulation and anticoagulation, fibrinolysis, endothelial cell activation, matricellular protein release, and tissue damage were measured at admission. Cox proportional hazard models were used to assess variables associated with 12-week mortality rates.

Results

Of 59 patients with HIV-tuberculosis, 16 (27%) died after a median of 12 days (interquartile range, 0-24 days); 29 (64%) of the 45 not receiving anticoagulants fulfilled criteria for disseminated intravascular coagulation. Decreased survival time was associated with higher concentrations of markers of fibrinolysis, endothelial activation, matricellular protein release, and tissue damage and with decreased concentrations for markers of anticoagulation. In patients who died, coagulation factors involved in the common pathway were depleted (factor II, V, X), which corresponded to increased plasma clotting times. Mycobacteremia modestly influenced hemostatic changes without affecting mortality.

Conclusions

Patients with severe HIV-tuberculosis display a hypercoagulable state and activation of the endothelium, which is associated with mortality.

HIV infection rather than concurrent opportunistic infections drives most systemic procoagulant, vascular and damage responses - a prospective cohort study in central Africa

BACKGROUND

HIV infection is accompanied by various systemic host responses, including activation of coagulation and the vascular endothelium. We sought to determine the impact of opportunistic coinfections in a central African setting.

METHODS

This prospective study included 98 HIV-infected individuals in Gabon initiating combination antiretroviral therapy (cART) and followed them up for 6 months. Patients were stratified according to the presence of active tuberculosis (TB; n=19), mucocutaneous opportunistic infection (n=9) or no opportunistic infection (n=70). HIV-uninfected subjects were included as controls (n=32). Plasma concentrations of 14 markers of coagulation, endothelial activation, extracellular matrix formation and tissue damage were measured with a multiplex assay at baseline and months 3 and 6 after cART initiation.

RESULTS

HIV-infected patients showed elevated plasma levels of all biomarkers measured with exception of protein C, which was reduced. Concurrent TB was only associated with elevated concentrations of D-dimer, metallopeptidase inhibitor 1 and Tenascin-C. Mucocutaneous coinfection did not alter HIV-associated responses. Most markers measured declined but remained elevated despite response to cART.

CONCLUSIONS

HIV infection is associated with systemic pro-coagulant, vascular and damage responses. In an ambulatory setting, concurrent opportunistic infections have little if any influence on these responses and normalization is incomplete after response to cART. This suggests that these responses are mainly driven by HIV-associated immune activation and less so by opportunistic infections.

Tissue inhibitor of metalloproteinases 1, a novel biomarker of tuberculosis

Tuberculosis (TB) is an important infectious disease of humans and other animals. Conventional diagnostic methods, including the tuberculin skin test, chest X‑rays and bacterial culture, have certain innate disadvantages for the early, rapid and specific diagnosis of tuberculosis. The present study aimed to identify a novel diagnostic biomarker to overcome these disadvantages. The potential target identified in the present study was tissue inhibitor of metalloproteinases 1 (TIMP‑1), which has previously been demonstrated to be critical in the immune response to TB. The concentration of TIMP‑1 in the blood was determined using a commercial ELISA kit, and the relative mRNA expression levels following bacterial infection were detected by reverse transcription‑quantitative polymerase chain reaction. Based on a clinical and microbiological diagnosis, the ELISA for plasma TIMP‑1 had a sensitivity of 91.80% [95% confidence interval (CI): 85.44, 96.00] and a specificity of 91.41% (95% CI: 85.14, 95.63). In a THP‑1 cell model, Bacillus Calmette‑Guérin and Mycobacterium bovis significantly upregulated the mRNA expression levels of TIMP‑1 post infection in a time‑dependent manner (P=0.006 for BCG 24 h PI, P=3.2x10‑7 for M. bovis 24 PI). The results of the present study indicate that plasma TIMP‑1 may be a potential biomarker for the diagnosis of TB.

Matrix Metalloproteinases in Non-Neoplastic Disorders

The matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases belonging to the metzincin superfamily. There are at least 23 members of MMPs ever reported in human, and they and their substrates are widely expressed in many tissues. Recent growing evidence has established that MMP not only can degrade a variety of components of extracellular matrix, but also can cleave and activate various non-matrix proteins, including cytokines, chemokines and growth factors, contributing to both physiological and pathological processes. In normal conditions, MMP expression and activity are tightly regulated via interactions between their activators and inhibitors. Imbalance among these factors, however, results in dysregulated MMP activity, which causes tissue destruction and functional alteration or local inflammation, leading to the development of diverse diseases, such as cardiovascular disease, arthritis, neurodegenerative disease, as well as cancer. This article focuses on the accumulated evidence supporting a wide range of roles of MMPs in various non-neoplastic diseases and provides an outlook on the therapeutic potential of inhibiting MMP action.

Rational design of antirheumatic prodrugs specific for sites of inflammation

Objective

Biologic drugs, such as the anti–tumor necrosis factor (anti‐TNF) antibody adalimumab, have represented a breakthrough in the treatment of rheumatoid arthritis. Yet, concerns remain over their lack of efficacy in a sizable proportion of patients and their potential for systemic side effects such as infection. Improved biologic prodrugs specifically targeted to the site of inflammation have the potential to alleviate current concerns surrounding biologic anticytokine therapies. The purpose of this study was to design, construct, and evaluate in vitro and ex vivo the targeting and antiinflammatory capacity of activatable bispecific antibodies.

Methods

Activatable dual variable domain (aDVD) antibodies were designed and constructed to target intercellular adhesion molecule 1 (ICAM‐1), which is up‐regulated at sites of inflammation, and anti‐TNF antibodies (adalimumab and infliximab). These bispecific molecules included an external arm that targets ICAM‐1 and an internal arm that comprises the therapeutic domain of an anti‐TNF antibody. Both arms were linked to matrix metalloproteinase (MMP)–cleavable linkers. The constructs were tested for their ability to bind and neutralize both in vitro and ex vivo targets.

Results

Intact aDVD constructs demonstrated significantly reduced binding and anti‐TNF activity in the prodrug formulation as compared to the parent antibodies. Human synovial fluid and physiologic concentrations of MMP enzyme were capable of cleaving the external domain of the antibody, revealing a fully active molecule. Activated antibodies retained the same binding and anti‐TNF inhibitory capacities as the parent molecules.

Conclusion

The design of a biologic prodrug with enhanced specificity for sites of inflammation (synovium) and reduced specificity for off‐target TNF is described. This construct has the potential to form a platform technology that is capable of enhancing the therapeutic index of drugs for the treatment of RA and other inflammatory diseases.

Tissue factor expression by myeloid cells contributes to protective immune response against Mycobacterium tuberculosis infection

Tissue factor (TF) is a transmembrane glycoprotein that plays an essential role in hemostasis by activating coagulation. TF is also expressed by monocytes/macrophages as part of the innate immune response to infections. In the current study, we determined the role of TF expressed by myeloid cells during Mycobacterium tuberculosis (M. tb) infection by using mice lacking the TF gene in myeloid cells (TF(Δ) ) and human monocyte derived macrophages (MDMs). We found that during M. tb infection, a deficiency of TF in myeloid cells was associated with reduced inducible nitric oxide synthase (iNOS) expression, enhanced arginase 1 (Arg1) expression, enhanced IL-10 production and reduced apoptosis in infected macrophages, which augmented M. tb growth. Our results demonstrate that a deficiency of TF in myeloid cells promotes M2-like phenotype in M .tb infected macrophages. A deficiency in TF expression by myeloid cells was also associated with reduced fibrin deposition and increased matrix metalloproteases (MMP)-2 and MMP-9 mediated inflammation in M. tb infected lungs. Our studies demonstrate that TF expressed by myeloid cells has newly recognized abilities to polarize macrophages and to regulate M. tb growth.

Differential expression of HLA-G and ILT-2 receptor in human tuberculosis: Localized versus disseminated disease

Human leukocyte antigen-G (HLA-G) is an anti-inflammatory and immunosuppressive molecule that can modulate immune cell activation. The role of HLA-G in tuberculosis, an immune-mediated and chronic bacterial disease remains to be elucidated. We investigated the expression profile of soluble and membrane bound HLA-G in pulmonary TB (PTB), TB pleural effusion (TB-PE, localized disease) and Miliary TB (disseminated form). The expression of HLA-G receptor, ILT-2 was also determined on the immune cells. We observed that the plasma sHLA-G levels were significantly increased in Miliary TB than in TB-PE patients. In contrast, immunophenotyping revealed that the percent frequency of CD3(+) T cells expressing HLA-G was significantly reduced in Miliary TB as compared to TB-PE, whereas frequency of CD14(+) monocytes expressing HLA-G was significantly higher in TB-PE patients. Strikingly in the TB-PE cases, comparison of disease site, i.e. pleural effusion with peripheral blood showed increased expression of both soluble and surface HLA-G, whereas ILT-2 expressing cells were reduced at the local disease site. Furthermore, we demonstrated that in TB-PE cases, HLA-G expression on CD3(+) T cells was influenced by broad spectrum MMP inhibitor. Thus, differential expression of HLA-G could potentially be a useful biomarker to distinguish different states of TB disease.

Tissue inhibitor of metalloproteinase-1 is responsible for residual pleural thickening in pleural tuberculosis

Residual pleural thickening (RPT) is the most frequent complication associated with pleural tuberculosis, and may occur even after successful anti-tuberculosis medications. Matrix metalloproteinases (MMPs) are zinc-dependent proteinases capable of degrading all components of the extracellular matrix. The proteolytic action of MMPs may be involved in the pathogenesis of tuberculosis. MMP-9, secreted by monocytes and lymphocyte, may lead to long-term fibrosis. The aim of the present study was to determine whether MMP-2 and/or MMP-9 and their specific inhibitors, tissue inhibitors of metalloproteinase 1 (TIMP-1) and TIMP-2, could be used to predict RPT. This retrospective study enrolled 52 patients diagnosed with pleural tuberculosis. Levels of MMP-2, MMP-9, TIMP-1, and TIM-2 were determined in the pleural fluid by ELISA. The RPT was measured on chest X-ray at the completion of treatment and the final follow-up. The average periods of anti-tuberculosis medication and the follow-up after completion of treatment were 6.7 and 7.6 months, respectively. MMP-2 or MMP-9 levels had no significant correlation to RPT. The patients with RPT > 2 mm at the completion of anti-tuberculosis medication and the final follow-up had higher TIMP-1 levels (p = 0.00 and p = 0.001, respectively). However, patients with RPT > 2 mm at the completion of anti-tuberculosis medication had lower TIMP-2 levels (p = 0.005). In a logistic regression model, elevated TIMP-1 levels at the completion of anti-tuberculosis medications were associated with RPT. In conclusion, higher TIMP-1 levels are responsible for the development of RPT and may be helpful for predicting RPT in pleural tuberculosis.

Matrix Metalloproteinases in Tuberculosis-Immune Reconstitution Inflammatory Syndrome and Impaired Lung Function Among Advanced HIV/TB Co-infected Patients Initiating Antiretroviral Therapy

Background

HIV-infected patients with pulmonary TB (pTB) can have worsening of respiratory symptoms as part of TB-immune reconstitution inflammatory syndrome (TB-IRIS) following antiretroviral therapy (ART) initiation. Thus, reconstitution of immune function on ART could drive incident lung damage in HIV/TB.

Methods

We hypothesized that increases in matrix metalloproteinases (MMPs), which can degrade lung matrix, on ART are associated with TB-IRIS among a cohort of advanced, ART naïve, HIV-infected adults with pTB. Furthermore, we related early changes in immune measures and MMPs on ART to lung function in an exploratory subset of patients post-TB cure. This study was nested within a prospective cohort study. Rank sum and chi-square tests, Spearman's correlation coefficient, and logistic regression were used for analyses.

Results

Increases in MMP-8 following ART initiation were independently associated with TB-IRIS (p = 0.04; adjusted odds ratio 1.5 [95% confidence interval: 1.0–2.1]; n = 32). Increases in CD4 counts and MMP-8 on ART were also associated with reduced forced expiratory volume in one-second post-TB treatment completion (r = − 0.7, p = 0.006 and r = − 0.6, p = 0.02, respectively; n = 14).

Conclusions

ART-induced MMP increases are associated with TB-IRIS and may affect lung function post-TB cure. End-organ damage due to TB-IRIS and mechanisms whereby immune restoration impairs lung function in pTB deserve further investigation.

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Matrix metalloproteinases (MMP), capable of degrading lung collagen, can increase rapidly on ART in HIV/TB patients.

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Increases in plasma MMP-8 concentrations after ART initiation are associated with the development of paradoxical TB-IRIS.

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Increases in CD4 T-cells and MMP-8 concentrations after ART initiation are correlated with decreased lung function post-TB cure.

TB-associated pulmonary morbidity can persist after TB cure. However, causal mechanisms for lung damage, which may involve immune mechanisms and tissue proteases, in TB are unclear. Less is known in this regard among patients with HIV/TB, who are at risk for inflammatory reactions following ART initiation, otherwise known as TB-immune reconstitution inflammatory syndrome (IRIS). In this study, rapid ART-induced increases in certain tissue degrading proteins called matrix metalloproteinases (MMP) were associated with TB-IRIS. Furthermore, rapid recovery of CD4 T-cells and MMP-8 concentrations were associated with decreased lung function in an exploratory subset. In HIV/TB, robust increases in cellular immune function and MMPs on ART may underlie lung injury and long-term pulmonary deficits.

Mycobacterium tuberculosis Upregulates TNF-α Expression via TLR2/ERK Signaling and Induces MMP-1 and MMP-9 Production in Human Pleural Mesothelial Cells

BACKGROUND

Tumor necrosis factor (TNF)-α and matrix metalloproteinases (MMPs) are elevated in pleural fluids of tuberculous pleuritis (TBP) where pleural mesothelial cells (PMCs) conduct the first-line defense against Mycobacterium tuberculosis (MTB). However, the clinical implication of TNF-α and MMPs in TBP and the response of PMCs to MTB infection remain unclear.

METHODS

We measured pleural fluid levels of TNF-α and MMPs in patients with TBP (n = 18) or heart failure (n = 18) as controls. Radiological scores for initial effusion amount and residual pleural fibrosis at 6-month follow-up were assessed. In vitro human PMC experiments were performed to assess the effect of heat-killed M. tuberculosis H37Ra (MTBRa) on the expression of TNF-α and MMPs.

RESULTS

As compared with controls, the effusion levels of TNF-α, MMP-1 and MMP-9 were significantly higher and correlated positively with initial effusion amount in patients with TBP, while TNF-α and MMP-1, but not MMP-9, were positively associated with residual pleural fibrosis of TBP. Moreover, effusion levels of TNF-α had positive correlation with those of MMP-1 and MMP-9 in TBP. In cultured PMCs, MTBRa enhanced TLR2 and TLR4 expression, activated ERK signaling, and upregulated TNF-α mRNA and protein expression. Furthermore, knockdown of TLR2, but not TLR4, significantly inhibited ERK phosphorylation and TNF-α expression. Additionally, both MTBRa and TNF-α markedly induced MMP-1 and MMP-9 synthesis in human PMCs, and TNF-α neutralization substantially reduced the production of MMP-1, but not MMP-9, in response to MTBRa stimulation.

CONCLUSION

MTBRa activates TLR2/ERK signalings to induce TNF-α and elicit MMP-1 and MMP-9 in human PMCs, which are associated with effusion volume and pleural fibrosis and may contribute to pathogenesis of TBP. Further investigation of manipulation of TNF-α and MMP expression in pleural mesothelium may provide new insights into the mechanisms and rational treatment strategies for TBP.

Lesion-Specific Immune Response in Granulomas of Patients with Pulmonary Tuberculosis: A Pilot Study

The formation and maintenance of granulomas is central to the host response to Mycobacterium tuberculosis (Mtb) infection. It is widely accepted that the lungs of patients with tuberculosis (TB) usually contain multiple infection foci, and that the granulomas evolve and differentiate independently, resulting in considerable heterogeneity. Although gene expression profiles of human blood cells have been proposed as biomarkers of Mtb infection and/or active disease, the immune profiles of discrete lesion types has not been studied extensively. Using histology, immunopathology and genome-wide transcriptome analysis, we explored the immunological profile of human lung TB granulomas. We show that although the different granulomas share core similarities in their immunological/inflammatory characteristics, they also exhibit significant divergence. Despite similar numbers of CD68⁺ macrophages in the different lesions, the extent of immune reactivity, as determined by the density of CD3⁺ T cells in the macrophage rich areas, and the extent of fibrosis, shows considerable variation. Both quantitative and qualitative differences among significantly differentially expressed genes (SDEG) were noted in each of the lesion types studied. Further, network/pathway analysis of SDEG revealed differential regulation of inflammatory response, immune cell trafficking, and cell mediated immune response in the different lesions. Our data highlight the formidable challenges facing ongoing efforts to identify peripheral blood biomarkers due to the diversity of lesion types and complexity of local immune responses in the lung.

Matrix metalloproteinase-sensitive hydrogel microparticles for pulmonary drug delivery of small molecule drugs or proteins

Hydrogel microparticles are particularly attractive for pulmonary drug delivery. Their size can be engineered for efficient delivery into the bronchi, where they subsequently swell, avoiding macrophage uptake. In this study, enzyme-responsive peptide functionalized poly(ethylene glycol) (PEG) based hydrogel microparticles were synthesized by an emulsion polymerization. Here, we demonstrate that these microparticles are nontoxic and demonstrated their viability as a drug carrier by studying the encapsulation and release of three types of drugs: a hydrophobic (dexamethasone), a hydrophilic (methylene blue) and a protein (horseradish peroxidase)-based drug. The release of each of these three drugs was studied in the presence of varying concentrations of matrix metalloproteinase (MMP). Each of the three types of drugs were able to be encapsulated in the microparticles, and we further showed that the protein is still functional after release.

Enzyme-responsive hydrogel microparticles for pulmonary drug delivery

Poly(ethylene glycol) based hydrogel microparticles were developed for pulmonary drug delivery. Hydrogels are particularly attractive for pulmonary delivery because they can be size engineered for delivery into the bronchi, yet also swell upon reaching their destination to avoid uptake and clearance by alveolar macrophages. To develop enzyme-responsive hydrogel microparticles for pulmonary delivery a new synthesis method based on a solution polymerization was developed. This method produces spherical poly(ethylene glycol) (PEG) microparticles from high molecular weight poly(ethylene glycol) diacrylate (PEGDA)-based precursors that incorporate peptides in the polymer chain. Specifically, we have synthesized hydrogel microparticles that degrade in response to matrix metalloproteinases that are overexpressed in pulmonary diseases. Small hydrogel microparticles with sizes suitable for lung delivery by inhalation were obtained from solid precursors when PEGDA was dissolved in water at a high concentration. The average diameter of the particles was between 2.8 and 4 μm, depending on the molecular weight of the precursor polymer used and its concentration in water. The relation between the physical properties of the particles and their enzymatic degradation is also reported, where an increased mesh size corresponds to increased degradation.

Induced sputum MMP-1, -3 & -8 concentrations during treatment of tuberculosis

INTRODUCTION

Tuberculosis (TB) destroys lung tissues and this immunopathology is mediated in part by Matrix Metalloproteinases (MMPs). There are no data on the relationship between local tissue MMPs concentrations, anti-tuberculosis therapy and sputum conversion.

MATERIALS AND METHODS

Induced sputum was collected from 68 TB patients and 69 controls in a cross-sectional study. MMPs concentrations were measured by Luminex array, TIMP concentrations by ELISA and were correlated with a disease severity score (TBscore). 46 TB patients were then studied longitudinally at the 2nd, 8th week and end of treatment.

RESULTS

Sputum MMP-1,-2,-3,-8,-9 and TIMP-1 and -2 concentrations are increased in TB. Elevated MMP-1 and -3 concentrations are independently associated with higher TB severity scores (p<0.05). MMP-1, -3 and -8 concentrations decreased rapidly during treatment (p<0.05) whilst there was a transient increase in TIMP-1/2 concentrations at week 2. MMP-2, -8 and -9 and TIMP-2 concentrations were higher at TB diagnosis in patients who remain sputum culture positive at 2 weeks and MMP-3, -8 and TIMP-1 concentrations were higher in these patients at 2nd week of TB treatment.

CONCLUSIONS

MMPs are elevated in TB patients and associate with disease severity. This matrix-degrading phenotype resolves rapidly with treatment. The MMP profile at presentation correlates with a delayed treatment response.

Mycobacterial trehalose dimycolate reprograms macrophage global gene expression and activates matrix metalloproteinases

Trehalose 6,6'-dimycolate (TDM) is a cell wall glycolipid and an important virulence factor of mycobacteria. In order to study the role of TDM in the innate immune response to Mycobacterium tuberculosis, microarray analysis was used to examine gene regulation in murine bone marrow-derived macrophages in response to 90-μm-diameter polystyrene microspheres coated with TDM. A large number of genes, particularly those involved in the immune response and macrophage function, were up- or downregulated in response to these TDM-coated beads compared to control beads. Genes involved in the immune response were specifically upregulated in a myeloid differentiation primary response gene 88 (MyD88)-dependent manner. The complexity of the transcriptional response also increased greatly between 2 and 24 h. Matrix metalloproteinases (MMPs) were significantly upregulated at both time points, and this was confirmed by quantitative real-time reverse transcription-PCR (RT-PCR). Using an in vivo Matrigel granuloma model, the presence and activity of MMP-9 were examined by immunohistochemistry and in situ zymography (ISZ), respectively. We found that TDM-coated beads induced MMP-9 expression and activity in Matrigel granulomas. Macrophages were primarily responsible for MMP-9 expression, as granulomas from neutrophil-depleted mice showed staining patterns similar to that for wild-type mice. The relevance of these observations to human disease is supported by the similar induction of MMP-9 in human caseous tuberculosis (TB) granulomas. Given that MMPs likely play an important role in both the construction and breakdown of tuberculous granulomas, our results suggest that TDM may drive MMP expression during TB pathogenesis.

Host gene-encoded severe lung TB: from genes to the potential pathways

We are reporting that the two-locus genotype -2518 macrophage chemoattractant protein (MCP)-1 GG and -1607 matrix metalloproteinase (MMP)-1 2G/2G promotes the expression of hyperinflammation in response to Mycobacterium tuberculosis infection, inducing extensive tissue damage and severe tuberculosis (TB) disease. Carriers of this two-locus genotype have a 13-fold higher chance of developing severe disease and 6.5-fold higher chance of developing permanent lesions, and a 3.864-fold higher chance of delayed response to first-line standardized treatment than carriers of any other relevant combination of genotypes at those two loci. Thus, these persons have an increased likelihood of poor health-related quality of life and of transmitting M. tuberculosis to other members of the community. In addition, through the analysis of human lung tissues, serum/plasma and in vitro experiments, including in vitro infections of THP-1 cells with M. tuberculosis and microarray analysis, we determined that this hyperinflammation state is potentially driven by the MCP-1/MMP-1/PAR-1 pathway. Hence, we are providing markers for the identification of TB cases that may develop severe pulmonary disease and delayed response to treatment, and are providing the basis for development of novel host-targeted clinical interventions to ameliorate the severity of pulmonary TB.

ACE/ACE2 ratio and MMP-9 activity as potential biomarkers in tuberculous pleural effusions

OBJECTIVE

Pleural effusion is common problem, but the rapid and reliable diagnosis for specific pathogenic effusions are lacking. This study aimed to identify the diagnosis based on clinical variables to differentiate pleural tuberculous exudates from other pleural effusions. We also investigated the role of renin-angiotensin system (RAS) and matrix metalloproteinase (MMPs) in the pathogenesis of pleural exudates.

EXPERIMENTAL DESIGN

The major components in RAS and extracellular matrix metabolism, including angiotensin converting enzyme (ACE), ACE2, MMP-2 and MMP-9 activities, were measured and compared in the patients with transudative (n = 45) and exudative (n = 80) effusions. The exudative effusions were come from the patients with tuberculosis (n = 20), pneumonia (n = 32), and adenocarcinoma (n = 28).

RESULTS

Increased ACE and equivalent ACE2 activities, resulting in a significantly increased ACE/ACE2 ratio in exudates, were detected compared to these values in transudates. MMP-9 activity in exudates was significantly higher than that in transudates. The significant correlation between ACE and ACE2 activity that was found in transudates was not found in exudates. Advanced analyses showed significantly increased ACE and MMP-9 activities, and decreased ACE2 activity in tuberculous pleural effusions compared with those in pneumonia and adenocarcinoma effusions. The results indicate that increased ACE and MMP-9 activities found in the exudates were mainly contributed from a higher level of both enzyme activities in the tuberculous pleural effusions.

CONCLUSION

Interplay between ACE and ACE2, essential functions in the RAS, and abnormal regulation of MMP-9 probably play a pivotal role in the development of exudative effusions. Moreover, the ACE/ACE2 ratio combined with MMP-9 activity in pleural fluid may be potential biomarkers for diagnosing tuberculous pleurisy.

Comparison of localized versus systemic levels of Matrix metalloproteinases (MMPs), its tissue inhibitors (TIMPs) and cytokines in tuberculous and non-tuberculous pleuritis patients

The interaction of Matrix metalloproteinases (MMPs), its tissue inhibitors (TIMPs) and pro-inflammatory cytokines in response to Mycobacterium tuberculosis (MTB) infection is important to understand the immune response at the site of infection. We compared the levels of MMPs, TIMPs and cytokines in plasma (BL) and pleural fluid (PF) of tuberculosis (TB) and non tuberculosis (NTB) patients. Comparison between BL and PF showed significantly higher levels of MMP-1, TIMP-1 and -3 in TB PF; of MMP-7, -8, -9 in BL of both groups. Also, levels of MMP-1,-8,-9 and TIMP-3 were significantly higher in TB PF compared to NTB. Cytokines INF-γ, TNF-α, and IL-6 significantly increased in PF of both groups. A positive correlation of MMPs with TIMPs in TB, MMP-1 and -9 with IL-6 in TB PF and MMP-9 with IFN-γ in NTB PF was observed. This study implicates the possible usage of MMPs as bio-markers aiding diagnosis in TB pleuritis.

Transcriptional response of peripheral blood mononuclear cells from cattle infected with Mycobacterium bovis

Mycobacterium bovis is the causative agent of most cases of bovine tuberculosis. The identification of bTB biomarkers in specific stages of the disease will contribute to a better understanding of the immunopathology associated with tuberculosis and will enable their use in disease diagnosis and prognosis. The aim of this study was to evaluate the gene expression profile induced after specific stimulation of bovine peripheral blood mononuclear cells from cattle infected with M. bovis using the Affymetrix® GeneChip® Bovine Genome Array. A total of 172 genes showed differential expression profile that was statistically significant with log2-fold change >2.5 and <−2.5. Twenty-four out of these genes were upregulated and 148 were downregulated in bovine peripheral blood mononuclear cells of M. bovis-infected cattle. The highest differentially-expressed genes were related to immune and inflammatory responses, apoptosis, endocytosis, cellular trafficking and genes encoding proteins involved in cellular matrix degradation. Microarray results were confirmed in another group of infected cattle by RT-qPCR for the CD14, IL-1R, THBS1, MMP9 and FYVE genes. This study confirms previous findings that have shown that M. bovis infection in cattle results in the downregulation of immune response-related genes. Moreover, it validates the use of microarray platforms in combination with RT-qPCR to identify biomarkers of bovine tuberculosis. In addition, we propose CD14, IL-1R, THBS1, MMP9 and FYVE as potential biomarkers of bovine tuberculosis.

Predominance of interleukin-22 over interleukin-17 at the site of disease in human tuberculosis

The inflammatory response to Mycobacterium tuberculosis (M.tb) at the site of disease is Th1 driven. Whether the Th17 cytokines, IL-17 and IL-22, contribute to this response in humans is unknown. We hypothesized that IL-17 and IL-22 contribute to the inflammatory response in pleural and pericardial disease sites of human tuberculosis (TB). We studied pleural and pericardial effusions, established TB disease sites, from HIV-uninfected TB patients. Levels of soluble cytokines were measured by ELISA and MMP-9 by luminex. Bronchoalveolar lavage or pericardial mycobacteria-specific T cell cytokine expression was analyzed by intracellular cytokine staining. IL-17 was not abundant in pleural or pericardial fluid. IL-17 expression by mycobacteria-specific disease site T cells was not detected in healthy, M.tb-infected persons, or patients with TB pericarditis. These data do not support a major role for IL-17 at established TB disease sites in humans. IL-22 was readily detected in fluid from both disease sites. These IL-22 levels exceeded matching peripheral blood levels. Further, IL-22 levels in pericardial fluid correlated positively with MMP-9, an enzyme known to degrade the pulmonary extracellular matrix. We propose that our findings support a role for IL-22 in TB-induced pathology or the resulting repair process.

Joint effect of MCP-1 genotype GG and MMP-1 genotype 2G/2G increases the likelihood of developing pulmonary tuberculosis in BCG-vaccinated individuals

We previously reported that the – 2518 MCP-1 genotype GG increases the likelihood of developing tuberculosis (TB) in non-BCG-vaccinated Mexicans and Koreans. Here, we tested the hypothesis that this genotype, alone or together with the – 1607 MMP-1 functional polymorphism, increases the likelihood of developing TB in BCG-vaccinated individuals. We conducted population-based case-control studies of BCG-vaccinated individuals in Mexico and Peru that included 193 TB cases and 243 healthy tuberculin-positive controls from Mexico and 701 TB cases and 796 controls from Peru. We also performed immunohistochemistry (IHC) analysis of lymph nodes from carriers of relevant two-locus genotypes and in vitro studies to determine how these variants may operate to increase the risk of developing active disease. We report that a joint effect between the – 2518 MCP-1 genotype GG and the – 1607 MMP-1 genotype 2G/2G consistently increases the odds of developing TB 3.59-fold in Mexicans and 3.9-fold in Peruvians. IHC analysis of lymph nodes indicated that carriers of the two-locus genotype MCP-1 GG MMP-1 2G/2G express the highest levels of both MCP-1 and MMP-1. Carriers of these susceptibility genotypes might be at increased risk of developing TB because they produce high levels of MCP-1, which enhances the induction of MMP-1 production by M. tuberculosis-sonicate antigens to higher levels than in carriers of the other two-locus MCP-1 MMP-1 genotypes studied. This notion was supported by in vitro experiments and luciferase based promoter activity assay. MMP-1 may destabilize granuloma formation and promote tissue damage and disease progression early in the infection. Our findings may foster the development of new and personalized therapeutic approaches targeting MCP-1 and/or MMP-1.

[Pulmonary and pleural tuberculosis in the elderly]

With the increase of the proportion of the elderly in the total population more cases of pulmonary and extrapulmonary tuberculosis (TB) are observed in this age group as well. Symptoms of TB are unspecific, often less apparent in the elderly, and may therefore cause a delay in the diagnostic process. A history of TB and comorbidities are more common in elder as compared to younger TB patients. The tuberculin skin test is less frequently positive. The interferon-gamma-release assay is complementary and together with clinical, radiologic, and bacteriologic test results helpful for the diagnosis or the exclusion of an active or latent TB infection. Medical treatment of TB in the elderly follows the established guidelines in the same way as for younger patients. The likelihood of drug-induced side effects and interactions with concomitant medications, however, is increased. Comorbidity and age-related immunosuppression may lead to a delay in the healing process. Higher age, comorbidity, and immunosuppression are predictors of an increased TB mortality. Even in a low-incidence country like Germany, TB should be recognized as an explanation for clinical symptoms particularly in the elderly patient group in order to allow an early diagnosis and therapy and thus a reduction of mortality and prevention of a further spread of this disease.

Dexamethasone, cerebrospinal fluid matrix metalloproteinase concentrations and clinical outcomes in tuberculous meningitis

Background

Adjunctive dexamethasone reduces mortality from tuberculous meningitis, but how it produces this effect is not known. Matrix metalloproteinases (MMPs) are important in the immunopathology of many inflammatory CNS diseases thus we hypothesized that that their secretion is important in TBM and might be influenced by dexamethasone.

Methodology/Principal Findings

The kinetics of cerebrospinal fluid (CSF) MMP and tissue inhibitors of MMPs (TIMPs) concentrations were studied in a subset of HIV uninfected adults (n = 37) with TBM recruited to a randomized, placebo-controlled trial of adjuvant dexamethasone. Analysis followed a pre-defined plan. Dexamethasone significantly reduced CSF MMP-9 concentrations in early follow up samples (median 5 days (range 3–8) of treatment), but had no significant influence on other MMPs/TIMPs. Additionally CSF MMP-9 concentration was strongly correlated to concomitant CSF neutrophil count.

Conclusions/Significance

Dexamethasone decreased CSF MMP-9 concentrations early in treatment and this may represent one mechanism by which corticosteroids improve outcome in TBM. The strong correlation between CSF MMP-9 and neutrophil count suggests that polymorphonuclear leukocytes may play a central role in the early pathogenesis of TBM.

PIM2 Induced COX-2 and MMP-9 expression in macrophages requires PI3K and Notch1 signaling

Activation of inflammatory immune responses during granuloma formation by the host upon infection of mycobacteria is one of the crucial steps that is often associated with tissue remodeling and breakdown of the extracellular matrix. In these complex processes, cyclooxygenase-2 (COX-2) plays a major role in chronic inflammation and matrix metalloproteinase-9 (MMP-9) significantly in tissue remodeling. In this study, we investigated the molecular mechanisms underlying Phosphatidyl-myo-inositol dimannosides (PIM2), an integral component of the mycobacterial envelope, triggered COX-2 and MMP-9 expression in macrophages. PIM2 triggers the activation of Phosphoinositide-3 Kinase (PI3K) and Notch1 signaling leading to COX-2 and MMP-9 expression in a Toll-like receptor 2 (TLR2)-MyD88 dependent manner. Notch1 signaling perturbations data demonstrate the involvement of the cross-talk with members of PI3K and Mitogen activated protein kinase pathway. Enforced expression of the cleaved Notch1 in macrophages induces the expression of COX-2 and MMP-9. PIM2 triggered significant p65 nuclear factor -κB (NF-κB) nuclear translocation that was dependent on activation of PI3K or Notch1 signaling. Furthermore, COX-2 and MMP-9 expression requires Notch1 mediated recruitment of Suppressor of Hairless (CSL) and NF-κB to respective promoters. Inhibition of PIM2 induced COX-2 resulted in marked reduction in MMP-9 expression clearly implicating the role of COX-2 dependent signaling events in driving the MMP-9 expression. Taken together, these data implicate PI3K and Notch1 signaling as obligatory early proximal signaling events during PIM2 induced COX-2 and MMP-9 expression in macrophages.

Matrix metalloproteinase-1 polymorphism in Taiwanese patients with endobronchial tuberculosis

Endobronchial tuberculosis (TB) often leads to some degree of tracheobronchial stenosis. Because matrix metalloproteinases (MMPs) play an essential role in tissue remodeling in the airways, we investigated the role of MMP-1 polymorphism in patients with endobronchial TB. One hundred and one cases of pulmonary TB in Taiwanese patients were genotyped for the 1G/2G polymorphism of MMP-1 promoter (-1607 bp). Bronchoscopic examination was performed to determine the presence of endobronchial involvement. Levels of MMP-1 in peripheral blood monocytes and in bronchial biopsies were also determined. 1G genotypes of MMP-1 polymorphism, containing at least one 1G allele, were associated with the presence of endobronchial TB. Using multivariate analysis, 1G genotypes and female gender were independent predictors of the development of endobronchial TB. Endobronchial TB patients with 1G genotypes had a 9.86-fold greater risk of developing tracheobronchial stenosis. IL-1beta increased levels of MMP-1 in peripheral blood monocytes of TB patients with 1G genotypes. MMP-1 activity was also present in the endobronchial TB granuloma from patients with 1G/1G genotype. 1G genotypes of MMP-1 polymorphism were associated with a greater risk of developing tracheobronchial stenosis through up-regulation of MMP-1 activity.

The chemokine receptor CXCR3 attenuates the control of chronic Mycobacterium tuberculosis infection in BALB/c mice

The chemokine receptor CXCR3 plays a significant role in regulating the migration of Th1 cells. Given the importance of Th1 immunity in the control of tuberculous infection, the results of the present study demonstrating that CXCR3-deficient BALB/c mice are more resistant to Mycobacterium tuberculosis, compared with wild-type mice, is surprising. This enhanced resistance manifests in the chronic but not the acute phase of infection. Remarkable differences in the cellular composition of the pulmonic granuloma of the CXCR3(-/-) and wild-type mice were found, the most striking being the increase in the number of CD4(+) T cells in the knockout strain. In the chronic phase of infection, the number of CD69-expressing CD4(+) T lymphocytes in the lungs of CXCR3(-/-) mice was higher than in wild-type mice. Additionally, at 1 mo postinfection, the number of IFN-gamma-producing CD4(+) T cells in the lungs and mediastinal lymph nodes of the CXCR3-deficient strain was elevated compared with wild-type mice. Pulmonic expression of IFN-gamma, IL-12, TNF-alpha, or NO synthase 2, the principal antimycobacterial factors, were equivalent in the two mouse strains. These results indicate that: 1) CXCR3 plays a role in modulating the cellular composition of tuberculous granuloma; 2) CXCR3 impairs antimycobacterial activity in chronic tuberculosis; and 3) in the absence of CXCR3, mice exhibit a heightened state of CD4(+) T lymphocyte activation in the chronic phase of infection that is associated with enhanced CD4(+) T cell priming. Therefore, CXCR3 can attenuate the host immune response to M. tuberculosis by adversely affecting T cell priming.

Role for matrix metalloproteinase 9 in granuloma formation during pulmonary Mycobacterium tuberculosis infection

Recent studies have shown that matrix metalloproteinases (MMPs) are induced by Mycobacterium tuberculosis during pulmonary infection. Here, expression of MMP-9 during pulmonary M. tuberculosis infection was characterized to determine whether its production correlated with disease resistance in vivo and to determine what role, if any, MMP-9 might have in granuloma formation. Following aerosol infection with M. tuberculosis, dissemination of bacilli occurred earlier in the C57BL/6 resistant mouse strain than in the susceptible CBA/J strain, as was evident from an increased number of bacteria in the blood, spleen, and liver at day 14 after infection. In addition, early dissemination of the bacilli was associated with early induction of protective immunity as assessed from gamma interferon levels. Nonspecific blocking of MMPs in C57BL/6 mice early during infection reduced hematogenous spread of the bacilli, suggesting that MMPs indeed play a role in facilitating dissemination, likely via extracellular matrix degradation. The concentration of active MMP-9, specifically, was greater in the lungs of C57BL/6 mice than in those of the CBA/J mice at day 28, thereby suggesting that MMP-9 is not one of the MMPs directly involved in promoting early dissemination of M. tuberculosis. Instead, however, histological lung sections and flow cytometric analysis of lung cells from MMP-9-knockout mice showed that MMP-9 is involved in macrophage recruitment and granuloma development. These combined data support the idea that early MMP activity is an essential component of resistance to pulmonary mycobacterial infection and that MMP-9, specifically, is required for recruitment of macrophages and tissue remodeling to allow for the formation of tight, well-organized granulomas.

Matrix metalloproteinases in destructive pulmonary pathology

Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that have a number of important physiological roles including remodelling of the extracellular matrix, facilitating cell migration, cleaving cytokines, and activating defensins. However, excess MMP activity may lead to tissue destruction. The biology of MMP and the role of these proteases in normal pulmonary immunity are reviewed, and evidence that implicates excess MMP activity in causing matrix breakdown in chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), sarcoidosis, and tuberculosis is discussed. Evidence from both clinical studies and animal models showing that stromal and inflammatory cell MMP expression leads to immunopathology is examined, and the mechanisms by which excess MMP activity may be targeted to improve clinical outcomes are discussed.

Matrix metalloproteinase-2 (MMP-2) and MMP-9 in pulmonary pathology

The lung is affected by a variety of disease processes that can lead to considerable morbidity and mortality. As the lung is the only organ for respiration and gas exchange, the structural and functional integrity of the lung is of primary importance. Various pathological processes affect the extracellular matrix (ECM) of the lung in an adverse manner, causing destruction of tissue integrity followed by tissue remodeling, which together impair normal pulmonary function. Matrix metalloproteinases (MMPs) are neutral proteinases that are involved in the breakdown and remodeling of the ECM under a variety of physiological and pathological conditions. MMP-2 and MMP-9, collectively known as the gelatinases, are particularly important in the pathogenesis of inflammatory, infectious, and neoplastic diseases in many organs including the lung. This review examines the expression of MMP-2 and MMP-9 in disease of the lung and discusses the role these gelatinases may play in disease progression.

Expression of matrix metalloproteinase-9 in pleural effusions of tuberculosis and lung cancer

BACKGROUND

Matrix metalloproteinase (MMP)-9 has been implicated in the development of pleural effusions.

OBJECTIVES

The aim of this study was to assess the expression of MMP-9 in pleural effusions of tuberculosis, lung cancer and transudates.

METHODS

Ninety-one patients (37 tuberculous pleural effusions, 42 malignant pleural effusions of lung cancer and 12 transudates) were included. Concentrations of pleural fluid MMP-9 and tissue inhibitors of matrix metalloproteinase (TIMP)-1 were determined by immunoassay. We also investigated the cellular localization of MMP-9 and TIMP-1 by reverse-transcriptase polymerase chain reaction on lymphocytes from pleural effusions and by immunohistochemical analysis of pleural tissues.

RESULTS

Pleural fluid MMP-9 levels, MMP-9/total protein and MMP-9/TIMP-1 ratios were significantly higher in tuberculous pleural effusions, whilst TIMP-1 levels were similar in the three groups. MMP-9 levels positively correlated with TIMP-1 and lactate dehydrogenase levels, and negatively with pH and glucose levels in pleural effusions. MMP-9 mRNA expression in lymphocytes tended to be higher in malignant pleural effusions of lung cancer than in the other groups without reaching statistical significance. The strongest immunoreactivity for MMP-9 was observed in epithelioid cells of tuberculous pleural tissues. Much lower levels of MMP-9 expression were found in tumor cells of pleural tissues.

CONCLUSIONS

MMP-9 is increased in tuberculous pleural effusions compared with transudates and malignant pleural effusions of lung cancer and is produced predominantly by epithelioid cells in the granulomas of tuberculous pleural tissues.

Progelatinase B/matrix metalloproteinase-9 proenzyme as a marker of pleural inflammation

Previous analyses of pleural effusions of different origin revealed high levels of matrix metalloproteinase-9 proenzyme (proMMP-9), predominantly in parainfectious exudates. To confirm the etiological association with inflammation and to explore time course of release of proMMP-9 under conditions of a local inflammatory reaction, the authors estimated proMMP-9 in pleural fluids of patients undergoing therapeutic talc pleurodesis (n = 20) and explorative thoracoscopy (n = 4), before, and at different time intervals after the intervention. The authors also compared proMMP-9 values with proinflammatory markers, such as interleukin-6 (IL-6), C-reactive protein (CRP), and leukocyte count. As revealed through scanning substrate electrophoresis, proMMP-9 levels increased within the first hours a!nd culminated 16 to 48 hours after intervention, amounting to 1.5- to 102 -fold of initial concentration (mean = 14.8 -fold). MMP-9 proenzyme values significantly correlated with the levels of proinflammatory cytokine IL-6 (r =.79, n = 47, p <.01) and with neutrophil counts (r =.75, n = 45, p <.01). In conclusion, the results present proMMP-9 as a novel early indicator of acute host-response in pleural space that complements traditional proinflammatory markers and might be useful in monitoring pleural inflammatory processes.

Differential diagnosis of pleural effusions by fuzzy-logic-based analysis of cytokines

Pleural effusions can be caused by highly different underlying diseases and are characterized by complex interactions of various local and circulating cells as well as numerous soluble parameters like interleukins (IL). Knowledge about this complex network could help to indicate underlying disease. Therefore, we have investigated immunoreactive concentrations of IL-4, IL-6, IL-11, IL-15, IL-17, IL-18, and tumor necrosis factor-alpha (TNF-alpha) in pleural effusions and peripheral blood from patients with tuberculosis, bronchial carcinoma and other carcinomas as well as congestive heart failure (CHF) and pneumonias. To determine the value of cytokine measurement for differential diagnosis, statistical and fuzzy-logic methods were applied. Quantitative analysis showed high concentrations of IL-6 and IL-11 only in pleural effusions. IL-15, IL-17, IL-18 and TNF-alpha could be detected also in blood plasma. Lowest amounts were detected in CHF indicating the non-inflammatory origin of effusions. Statistical analysis did not provide evidence for diagnostic relevance of singular cytokines. Fuzzy-logic analysis was able to assign patients to the correct diseases with 80% accuracy using IL-6 and IL-15 measurement. Our results confirm the pathogenetic role of these cytokines in pleural effusions. Fuzzy-logic-based procedures may help to characterize and distinguish effusions of unknown origin even in small patient groups.

Vascular endothelial growth factor correlates with matrix metalloproteinase-9 in the pleural effusion

Vascular endothelial growth factor (VEGF) is a potent, multifunctional cytokine that contributes to angiogenesis and inflammation. Matrix metalloproteinase-9 (MMP-9) is one of the major proteolytic enzymes that degrade various components of the extracellular matrix. Few data are available on the potential relationship between VEGF and MMP-9 in the accumulation of pleural effusion. We examined levels of VEGF and MMP-9 by means of enzyme immunoassay, zymographic analysis, and Western blot analysis in the patients with liver cirrhosis, tuberculosis, or lung cancer. The levels of VEGF and MMP-9 were significantly increased in the pleural fluids and sera of patients with tuberculosis and were even higher in patients with lung cancer compared with the patients with liver cirrhosis. A significant correlation was established between the level of VEGF and the level of MMP-9 in the pleural effusion. These results suggest that overproduction of VEGF and MMP-9 is associated with accumulation of the pleural effusion in tuberculosis and lung cancer. The relationship between VEGF and MMP-9 in the pleural effusion may have a role in the pathogenesis of pleural fluid formation.

Persistent increase of matrix metalloproteinases in cerebrospinal fluid of tuberculous meningitis

Matrix metalloproteinase (MMP)-2 and MMP-9 were analyzed by gelatin zymography and an enzyme-linked immunosorbent assay (ELISA) in a cerebrospinal fluid (CSF) from patients with tuberculous meningitis (n=24), acute aseptic meningitis (n=23) and the control (n=10). The MMP-2 and MMP-9 levels were significantly higher in the samples from the tuberculous meningitis patients than those from either the aseptic meningitis patients or the controls. In tuberculous meningitis, the patients with late neurologic complications had higher MMP-2 and MMP-9 levels than those without. The persistent increase in the MMP-2 and MMP-9 levels was associated with the development of complications following tuberculous meningitis. Inhibiting the MMPs may be an effective strategy for preventing or reducing the complications in tuberculous meningitis.