Elastase and matrix metalloproteinase inhibitors induce regression, and tenascin-C antisense prevents progression, of vascular disease
Kyle Northcote Cowan, … , Peter Lloyd Jones, Marlene Rabinovitch
Kyle Northcote Cowan, … , Peter Lloyd Jones, Marlene Rabinovitch
Published January 1, 2000
Citation Information: J Clin Invest. 2000;105(1):21-34. https://doi.org/10.1172/JCI6539.
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Article

Elastase and matrix metalloproteinase inhibitors induce regression, and tenascin-C antisense prevents progression, of vascular disease

Abstract

Increased expression of the glycoprotein tenascin-C (TN) is associated with progression of clinical and experimental pulmonary hypertension. In cultured smooth muscle cells (SMCs) TN is induced by matrix metalloproteinases (MMPs) and amplifies the proliferative response to growth factors. Conversely, suppression of TN leads to SMC apoptosis. We now report that hypertrophied rat pulmonary arteries in organ culture, which progressively thicken in association with cell proliferation and matrix accumulation, can be made to regress by inhibiting either serine elastases or MMPs. This effect is associated with reduced TN, suppression of SMC proliferation, and induction of apoptosis. Selective repression of TN by transfecting pulmonary arteries with antisense/ribozyme constructs also induces SMC apoptosis and arrests progressive vascular thickening but fails to induce regression. This failure is related to concomitant expansion of a SMC population, which produces an alternative cell survival αvβ3 ligand, osteopontin (OPN), in response to pro-proliferative cues provided by a proteolytic environment. OPN rescues MMP inhibitor–induced SMC apoptosis, and αvβ3 blockade induces apoptosis in hypertrophied arteries. Our data suggest that proteinase inhibition is a novel strategy to induce regression of vascular disease because this overcomes the pluripotentiality of SMC-matrix survival interactions and induces coordinated apoptosis and resorption of matrix.

Authors

Kyle Northcote Cowan, Peter Lloyd Jones, Marlene Rabinovitch

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Figure 13

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OPN- and αvβ3-mediated SMC survival. (a) Effect of exogenous OPN on apop...
OPN- and αvβ3-mediated SMC survival. (a) Effect of exogenous OPN on apoptosis of rat PA SMCs following MMP inhibition associated with loss of the SMC survival ligand TN. The addition of recombinant OPN to collagen gels prevented loss of cell number and rescued the SMCs from apoptosis, as assessed by loss of mitochondrial membrane potential (DePsipher positivity) described in Methods. Next we investigated the effect of αvβ3 integrin blockade in inducing apoptosis in hypertrophied PA organ cultures. Representative photomicrographs indicate that whereas apoptosis (bright green TUNEL-positive fluorescent nuclei) was minimal or absent in PAs after Mct injection both before culture, day 21 (b), and after 1 week of culture, either untreated (c) or treated with control IgG (d), unligation of the αvβ3 integrin with LM609 antibodies resulted in an abundant apoptotic response (e). This apoptosis, quantified in (f), was associated with regression of vascular hypertrophy as evident in the photomicrographs and as quantified in (g). Bars: 25 μm; graph bars: mean + SEM of 4 dishes or vessels; *P < 0.05 compared with DMSO control in a and IgG control in f and g; P < 0.05 compared with GM-6001 in a and preculture Mct (day 0) in f and g.