Ligation of CD40 Activates Interleukin 1β-converting Enzyme (Caspase-1) Activity in Vascular Smooth Muscle and Endothelial Cells and Promotes Elaboration of Active Interleukin 1β

Interleukin-1β–converting enzyme (ICE, caspase-1) regulates key steps in inflammation and immunity, by activating the proinflammatory cytokines interleukin (IL-)1β and IL-18, or mediating apoptotic processes. We recently provided evidence for the regulation of caspase-1 activity via an endogenous inhibitor expressed by human vascular smooth muscle cells (SMCs) (Schönbeck, U., M. Herzberg, A. Petersen, C. Wohlenberg, J. Gerdes, H.-D. Flad, and H. Loppnow. 1997. J. Exp. Med. 185:1287–1294). However, the molecular identity of this endogenous inhibitor remained undefined. We report here that the serine proteinase inhibitor (serpin) PI-9 accounts for the endogenous caspase-1 inhibitory activity in human SMCs and prevents processing of the enzyme's natural substrates, IL-1β and IL-18 precursor. Treatment of SMC lysates with anti–PI-9 antibody abrogated the caspase-1 inhibitory activity and coprecipitated the enzyme, demonstrating protein–protein interaction. Furthermore, PI-9 antisense oligonucleotides coordinately reduced PI-9 expression and promoted IL-1β release. Since SMCs comprise the majority of cells in the vascular wall, and because IL-1 is implicated in atherogenesis, we tested the biological validity of our in vitro findings within human atheroma in situ. The unaffected arterial wall contains abundant and homogeneously distributed PI-9. In human atherosclerotic lesions, however, PI-9 expression correlated inversely with immunoreactive IL-1β, supporting a potential role of the endogenous caspase-1 inhibitor in this chronic inflammatory disease. Thus, our results provide new insights into the regulation of this enzyme involved in immune and inflammatory processes of chronic inflammatory diseases, and point to an endogenous antiinflammatory action of PI-9, dysregulated in a prevalent human disease.

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Studies of Endothelin-Converting Enzyme in Bovine Endothelial Cells and Vascular Smooth-Muscle Cells: Further Characterization of the Biosynthetic Process

Journal of Cardiovascular Pharmacology ◽

10.1097/00005344-199800001-00015 ◽

1998 ◽

Vol 31 ◽

pp. S46-S48 ◽

Cited By ~ 5

Author(s):

Roger Corder ◽

Noorafza Khan ◽

Stewart Barker

Keyword(s):

Endothelial Cells ◽

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Vascular Smooth Muscle Cells ◽

Muscle Cells ◽

Converting Enzyme ◽

Endothelin Converting Enzyme ◽

Bovine Endothelial Cells

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A REVIEW ON ENDOTHELINS: AN UPDATE

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2018.v11i4.23255 ◽

2018 ◽

Vol 11 (4) ◽

pp. 38

Author(s):

Anitha Nandagopal ◽

Mubeen Unnisa Shamsia

Keyword(s):

Endothelial Cells ◽

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Vascular Smooth Muscle Cells ◽

Muscle Cells ◽

Converting Enzyme ◽

Endothelin Converting Enzyme ◽

Eta Receptor ◽

Potent Vasoconstrictor

Endothelin (ET) is the most potent vasoconstrictor. It is secreted by the endothelial cells. At low concentration, it acts as an agonist for endothelium-derived relaxing factors and thereby causes vasodilatation, and at higher concentration it acts as a potent vasoconstrictor. It is synthesized by proteolytic cleavage of preproendothelin to proendothelin by the action of metallopeptidases and chymase, which is further cleaved into mature form of ET by endothelin converting enzyme. There are four isoforms of ET, namely, ET-1, ET-2, ET-3, and ET-4. ET acts on 2 types of receptors. Binding of ET-1 to ETA receptor at the vascular smooth muscle cells induces vasoconstriction. It also produces vasoconstriction by acting on the ETB2 receptor of vascular smooth muscle cells but promotes vasodilatation at ETB1 receptor present on the endothelial cell.

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Human Vascular Smooth Muscle Cells Express Interleukin-1β–converting Enzyme (ICE), but Inhibit Processing of the Interleukin-1β Precursor by ICE

Journal of Experimental Medicine ◽

10.1084/jem.185.7.1287 ◽

1997 ◽

Vol 185 (7) ◽

pp. 1287-1294 ◽

Cited By ~ 29

Author(s):

Uwe Schönbeck ◽

Mona Herzberg ◽

Arnd Petersen ◽

Claudia Wohlenberg ◽

Johannes Gerdes ◽

...

Keyword(s):

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Biochemical Characterization ◽

Vascular Diseases ◽

Vascular Biology ◽

Molecular Size ◽

Interleukin 1Β ◽

Converting Enzyme ◽

Membrane Compartment ◽

And Function

Local immunoregulatory processes during normal vascular biology or pathogenesis are mediated in part by the production of and response to cytokines by vessel wall cells. Among these cytokines interleukin (IL)-1 is considered to be of major importance. Although vascular smooth muscle (SMC) and endothelial cells (EC) expressed both IL-1α and IL-1β as cell-associated, 33-kilodalton (kD) precursors, SMC neither contained detectable mature IL-1β, nor processed recombinant IL-1β precursor into its mature 17-kD form. Thus, we investigated the expression and function of IL-1β–converting enzyme (ICE) in vascular cells. We demonstrate in processing experiments with recombinant IL-1 precursor molecules that EC processed IL-1β, in contrast to SMC. Despite the failure of SMC to process IL-1β, these cells expressed ICE mRNA, immunoreactive ICE protein, and the expected IL-1β nucleotide sequence. The lack of processing was explained by our finding that extracts of SMC specifically and concentration dependently blocked processing of IL-1β precursor by recombinant or native ICE. The initial biochemical characterization of the inhibitory activity showed that it is heat-labile, has a molecular size of 50–100 kD, and is associated to the cell membrane compartment. Inhibition of processing, i.e., activation of IL-1β precursor by SMC may constitute a novel regulatory mechanism during normal vascular biology or pathogenesis of vascular diseases.

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Vascular Smooth Muscle Cells Inhibit the Plasminogen Activators Secreted by Endothelial Cells

Thrombosis and Haemostasis ◽

10.1055/s-0038-1661265 ◽

1985 ◽

Vol 53 (02) ◽

pp. 165-169 ◽

Cited By ~ 24

Author(s):

Walter E Laug

Keyword(s):

Endothelial Cells ◽

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Conditioned Medium ◽

Vascular Smooth Muscle Cells ◽

Inhibitory Activity ◽

Muscle Cells ◽

Plasminogen Activators ◽

Bovine Endothelial Cells

SummaryTPure cultures of bovine endothelial cells (EC) produce and secrete large amounts of plasminogen activators (PA). Cocultivation of EC with vascular smooth muscle cells (SMC) resulted in a significant decrease of PA activities secreted by the EC, whereas the cellular PA activities remained unaffected. Secreted PA activities were absent in the growth medium as long as the SMC to EC ratio was 2:1 or higher. The PA inhibitory activity of the SMC was rapid and cell-to-cell contact was not necessary.The PA inhibitory activity was present in homogenates of SMC as well as in the medium conditioned by them but not in the extracellular matrix elaborated by these cells. Serum free medium conditioned by SMC neutralized both tissue type (t-PA) and urokinase like (u-PA) plasminogen activators. Gel electrophoretic analysis of SMC conditioned medium followed by reverse fibrin autography demonstrated PA inhibitory activities in the molecular weight (Mr) range of 50,000 to 52,000 similar to those present in media conditioned by bovine endothelial cells or fibroblasts. Regular fibrin zymography of SMC conditioned medium incubated with u-PA or t-PA revealed the presence of a component with a calculated approximate Mr of 45,000 to 50,000 which formed SDS resistant complexes with both types of PA.These data demonstrate that vascular SMC produce and secrete (a) inhibitor(s) of PAs which may influence the fibrinolytic potential of EC.

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