Novel Proteolytic Microvesicles Released from Human Macrophages after Exposure to Tobacco Smoke

Abstract

Cigarette smoking damages the extracellular matrix in a variety of locations, leading to atherosclerotic plaque instability and emphysematous lung destruction, but the underlying mechanisms remain poorly understood. Here, we sought to determine whether exposure of human macrophages, a key participant in extracellular matrix damage, to tobacco smoke extract (TSE) induces the release of microvesicles (MVs; or microparticles) with proteolytic activity; the major proteases involved; and the cellular mechanisms that might mediate their generation. We found that MVs released from TSE-exposed macrophages carry substantial gelatinolytic and collagenolytic activities that surprisingly can be predominantly attributed to a single transmembrane protease of the matrix metalloproteinase (MMP) superfamily (namely, MMP14). Flow cytometric counts revealed that exposure of human macrophages to TSE for 20 hours more than quadrupled their production of MMP14-positive MVs (control, 1112 ± 231; TSE-induced, 5823 ± 2192 MMP14-positive MVs/μL of conditioned medium; means ± SEM; n = 6; P < 0.01). Our results indicate that the production of these MVs by human macrophages relies on a series of regulated steps that include activation of two mitogen-activated protein kinases (MAPKs, i.e., the Jun N-terminal kinase and p38 MAPK), and then MAPK-dependent induction and maturation of cellular MMP14, a remarkable accumulation of MMP14 into nascent plasma membrane blebs, and finally caspase- and MAPK-dependent apoptosis and apoptotic microvesicle generation. Proteolytically active MVs induced by tobacco smoke may be novel mediators of clinical important matrix destruction in smokers.

Extracellular vesicles released in response to respiratory exposures: implications for chronic disease

“…Li et al (2013) noted that CSE exposure of monocytes and monocyte-derived macrophages induced a threefold rise in EV-associated matrix metalloproteinase (MMP) 14-dependent gelatinolytic and collagenolytic activity. Folkesson et al (2015) found that, when exposed to CSE, neutrophil-like HL60 cells secreted EV-associated and proteolytically active a disintegrin and metalloproteinase (ADAM)10 and ADAM17.…”

Microparticles as Biomarkers of Vascular Dysfunction in Metabolic Syndrome and its Individual Components

“…Moreover, in vitro exposure of macrophages to tobacco smoke can directly induce the release of a mix of microparticles and exosomes carrying gelatinolytic and collagenolytic activities, mainly through the protease MMP14. These vesicles may be novel mediators of clinically important matrix destruction in smokers [77].…”

Mechanisms of development of multimorbidity in the elderly

“…Microparticles are also derived from other cell types, such as epithelial and inflammatory cells, but their roles are less well defined. For example, cigarette smoke stimulates the release of microparticles that have proteolytic activity (MMP14) from macrophages in vitro [103]. Endothelial microparticles containing miRNAs are increased in age-related vascular diseases, including atherosclerosis, hypertension and congestive cardiac failure [104,105].…”