Stromelysin-2 (MMP-10) facilitates clearance and moderates inflammation and cell death following lung exposure to long multiwalled carbon nanotubes

Tyler C Vandivort,1,2 Timothy P Birkland,1 Talita P Domiciano,3 Somenath Mitra,4 Terrance J Kavanagh,2 William C Parks1 1Cedars-Sinai Medical Center, Women’s Guild Lung Institute, Los Angeles, CA, 2Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, 3Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, CA, 4Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ, USA Abstract: Multiwalled carbon nanotubes (MWCNTs) are nanomaterials composed of multiple layers of graphene cylinders with unique properties that make them valuable for a number of industries. However, rising global production has led to concerns regarding potential occupational exposures to them as raw materials during handling. This is especially true for long MWCNT fibers, whose aspect ratio has been posited to initiate pathology similar to that of asbestos. Matrix metalloproteinases (MMPs) are a class of extracellular endopeptidases that control various processes related to tissue repair, inflammation, and more. Stromelysin-2 (MMP-10) has roles in modulating macrophage activation and function, and hence, we used an MMP-10 null (Mmp10-/-) mouse model to assess its role in controlling lung responses to inhaled long MWCNTs. Oropharyngeal aspiration of long MWCNTs (80 µg/mouse) by wild-type mice induced expression of Mmp10 mRNA, which was accompanied by a robust inflammatory response characterized by elevated expression of Tnfa, Il6, and Il1b. In Mmp10-/- mice, we found that absence of MMP-10 led to impaired pulmonary clearance of MWCNTs and reduced macrophage cell survival. Exposure of wild-type bone marrow-derived macrophages (BMDMs) and alveolar macrophages to MWCNTs caused a rapid, dose-dependent upregulation of Mmp10 mRNA expression, which was accompanied by expression of pro-inflammatory products (Il6 and Il1b). These products were further enhanced in Mmp10-/- macrophages, resulting in increased caspase-3-dependent cell death compared with wild-type cells. These findings indicate that MMP-10 facilitates the clearance of MWCNTs and moderates the pro-inflammatory response of exposed alveolar and infiltrated macrophages. Keywords: MMP-10, multiwalled carbon nanotubes, lung injury, macrophages, apoptosi

The effect of eosinophils on collagen gel contraction and implications for tissue remodelling

Asthma is characterized by an eosinophilic inflammation and a subepithelial fibrosis in the airways. Eosinophils contain several cytotoxic substances, such as eosinophil cationic protein (ECP), which can promote inflammation and cause tissue damage. This has generated the hypothesis that eosinophils may drive remodelling of extracellular matrix (ECM). To investigate the role of eosinophils we used an in vitro model for remodelling, the three-dimensional collagen gel contraction assay. Two sources of eosinophils were used in this study, isolated human peripheral eosinophils (purity > 95%) and stimulated [interleukin (IL)-5, IL-3 and granulocyte macrophage–colony stimulating factor (GM-CSF)] HL-60 clone 15 cells. Human eosinophils or HL-60 cells were cast together with human lung fibroblasts (HFL1) in type I collagen gels. Both types of eosinophils augmented fibroblast-mediated collagen gel contraction in a time and concentration-dependent manner. At 48 h, the gel area in HFL1/eosinophil co-culture was 46·5% ± 0·5 (mean ± s.e.m.) of initial area and in HFL1 culture 52·3% ± 0·1 (P < 0·001). Respective figures for HFL1/stimulated HL-60 co-culture and HFL1 culture only were 44·1% ± 0·5 and 52·4% ± 0·4 (P < 0·001). The release of ECP was increased when fibroblasts were cultured with eosinophils compared to eosinophils cultured alone. In addition, native ECP added to fibroblast gel cultures also augmented contraction. Our results suggest that eosinophils may interact with mesenchymal cells, promoting remodelling of ECM and that ECP constitutes one potential eosinophil-derived mediator driving this process. We conclude that this may be one important mechanism by which eosinophil–ECM interactions will lead to airway tissue remodelling in asthma

Tumor necrosis factor-α in human American tegumentary leishmaniasis

Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Protozoologia. Laboratório de Imunidade Celular e Hormonal. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Protozoologia. Laboratório de Imunidade Celular e Hormonal. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Protozoologia. Laboratório de Imunidade Celular e Hormonal. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Protozoologia. Laboratório de Imunidade Celular e Hormonal. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Protozoologia. Laboratório de Imunidade Celular e Hormonal. Rio de Janeiro, RJ, Brasil.Tumor necrosis factor-alpha (TNFα ) is a cytokine produced by activated macrophages and other cells. In order to verify whether the serum levels of TNFα in American tegumentary leishmaniasis patients are associated with the process of cure or aggravation of the disease, 41 patients were studied: 26 cases of cutaneous leishmaniasis (CL) and 15 of mucocutaneous leishmaniasis (MCL). During active disease the serum levels of TNFα of MCL patients were significantly higher than those of CL patients and control subjects (healthy individuals and cutaneous lesions from other etiologies). The MCL patients had serum titers of TNFα significantly lower at the end of antimonial therapy than before therapy. After a six-month follow-up, the MCL patients had serum levels of TNFα similar to those observed at the end of the therapy as well as to those of CL patients and control subjects. No significant variation in the serum levels of TNFα was observed in CL patients throughout the study period (before, at the end of therapy and after a six-month follow-up). The possible relationship between the high TNFα serum levels and severity of the disease is discussed

Down-regulation of tumor necrosis factor alpha activity by acute ethanol treatment in human peripheral blood monocytes

As the most commonly used drug that can modulate both metabolic and immune pathways, ethanol is evaluated in this report as a regulator of tumor necrosis factor alpha (TNF alpha) production in human peripheral blood monocytes (M phi) in combination with a variety of stimuli. While acute ethanol treatment did not induce TNF alpha in M phi, it was a potent down-regulator of M phi TNF alpha production whether induced by the combination of interferon-gamma plus muramyl dipeptide (MDP) (P \u3c 0.001), lipopolysaccharide (LPS) alone (P \u3c 0.01), or interferon-gamma plus LPS. Down-regulation of M phi TNF alpha by ethanol was dose dependent and statistically significant in the biologically relevant, 25-150 mM, ethanol concentration range. We also demonstrate that these ethanol concentrations did not affect M phi viability. TNF alpha down-regulation by ethanol was most effective when ethanol was administered 4 hr prior to MDP stimulation; however, it was also effective--though to a lesser extent--if it was added at the time of MDP stimulation. Furthermore, ethanol also down-regulated TNF alpha production of the in vivo preactivated M phi of trauma patients, which produce hyperelevated levels of TNF alpha. We have previously shown that the majority of posttrauma elevated M phi TNF alpha is produced by the M phi subpopulation expressing high-affinity type I Fc gamma receptors (Fc gamma RI). When the Fc gamma RI cross-linking-stimulated M phi subpopulation was treated with acute ethanol, TNF alpha production was suppressed again both in in vivo preactivated M phi of trauma patients and in M phi of normal controls.(ABSTRACT TRUNCATED AT 250 WORDS