EVE and beyond, retro and prospective insights

Marlene Rabinovitch

Division of Cardiovascular Research, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8


    ABSTRACT
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ABSTRACT
INTRODUCTION
EVE AND PULMONARY VASCULAR...
TN AND THE VASCULAR...
FN AND THE VASCULAR...
APPLICATION TO SYSTEMIC ARTERY...
REFERENCES

Our work has focused on the discovery that an endogenous vascular elastase (EVE) plays a pivotal role in the vascular changes associated with the development and progression of pulmonary hypertension. Recent studies have identified serum factors that stimulate transcription of this enzyme and have elucidated a signal transduction process involving activation of the mitogen-activated protein kinase pathway and nuclear expression of the transcription factor AML1. Proteases release and activate growth factors that are bound to the extracellular matrix and also induce, in a beta 3-integrin-dependent manner, the transcription of the gene for the matrix glycoprotein tenascin. Tenascin alters smooth muscle cell shape and facilitates the proliferative response to growth factors by clustering and activating growth factor receptors. In addition, breakdown products of elastin, elastin peptides, can upregulate the production of fibronectin, a glycoprotein that is critical to smooth muscle cell migration. The mechanisms regulating enhanced fibronectin production have recently been successfully targeted to prevent the development of intimal lesions.

endogenous vascular elastase; pulmonary hypertension; extracellular matrix; elastase; tenascin; fibronectin


    INTRODUCTION
TOP
ABSTRACT
INTRODUCTION
EVE AND PULMONARY VASCULAR...
TN AND THE VASCULAR...
FN AND THE VASCULAR...
APPLICATION TO SYSTEMIC ARTERY...
REFERENCES

OUR STUDIES began with EVE (endogenous vascular elastase). Like all mother figures, EVE likely has an important nurturing function suggested by the fact that the enzyme is expressed in the embryo at sites of vascular remodeling. Like the biblical Eve, however, the enzyme also has a darker side in that once reactivated in response to injury, it stimulates a zealous and misdirected remodeling that thickens the vessel wall and occludes the lumen.

EVE is a 20-kDa enzyme related to the serine proteinase adipsin (34). If there is an EVE, there must also be an Adam, and, indeed, the naturally occurring partner for EVE appears to be elafin, a 9-kDa serine elastase inhibitor first found in skin and bronchial secretions but also expressed in embryonic and postnatal vessel walls, accompanying and likely modulating the activities of EVE (21, 25, 26).


    EVE AND PULMONARY VASCULAR DISEASE: AN OVERVIEW
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INTRODUCTION
EVE AND PULMONARY VASCULAR...
TN AND THE VASCULAR...
FN AND THE VASCULAR...
APPLICATION TO SYSTEMIC ARTERY...
REFERENCES

Our evidence that EVE was important in the pathophysiology of pulmonary vascular disease was first suggested by electron-microscopic studies in which we showed fragmentation of elastin as an early feature of pulmonary vascular lesions in patients with congenital heart defects and left to right shunts (24). We measured an increase in serine elastase activity in the pulmonary arteries (PAs) of rats in which pulmonary hypertension was induced by exposure to hypoxia (15) or after injection with the toxin monocrotaline (29, 31). A cause-and-effect relationship was demonstrated in studies in which we showed that elastase inhibitors prevented pulmonary hypertension and associated vascular disease or greatly retarded its progression (15, 31).

Studies have been carried out in cultured endothelial and smooth muscle cells (SMCs) to investigate how pulmonary hypertension-producing stimuli such as the high flow and pressure of a congenital heart defect, hypoxia, or toxins might induce structural changes in PAs (Fig. 1). We reasoned that the structural and functional alterations in the endothelium (24) would result in loss of barrier function. This would, as a consequence, allow penetration into the subendothelium of a serum factor that could stimulate SMC production and the release of EVE. The idea that EVE could come from SMCs was predicated on the observations of the French investigators Hornebeck et al. (10), who first demonstrated activity of a serine elastase in cultured SMCs and in atherosclerotic tissues.


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Fig. 1.   Schema showing proposed role of elastase in pathogenesis of pulmonary vascular disease. EVE, endogenous vascular elastase; SMC, smooth muscle cell; bFGF, basic fibroblast growth factor-2; TGF-beta , transforming growth factor-beta .

Our studies (14, 27) have, in fact, shown that SMCs in culture degrade radiolabeled elastin when stimulated with serum- or endothelial-conditioned medium (Fig. 2). This is coupled with increased adhesion of radiolabeled elastin to the cell surface. In fact, pretreating elastin or cells with serum- or with endothelial-conditioned medium was as effective as serum alone and appeared to accelerate elastin degradation. The elastin binding elastase-inducing serum component appears to be, at least in part, attributed to apolipoprotein A1. The mechanism involves tethering elastin to the SMC surface and engaging it directly with the elastin binding protein. Tyrosine kinase-mediated intracellular signaling is induced, resulting in transcription of mRNA. There is increased expression of the transcription factor AML1, discovered by PCR differential display (30). AML1 is critical in white cell differentiation (a mutation causes acute myelogenous leukemia) and also has a recognition site in the promoter of neutrophil elastase (22), making it a likely candidate as a transcription factor for EVE (27).1


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Fig. 2.   Serum induction of elastolytic activity in fetal lamb pulmonary artery (PA) SMCs. Values are means ± SE of increase in elastolytic activity over that under serum-free conditions (i.e., 0.1% BSA) from 3 separate assays. There was significant elastolysis with a fetal bovine serum (FBS) concentration of only 0.1% (* P < 0.05 compared with serum-free condition), and maximum activity was evident with a concentration of 1% FBS, with no further increase observed with 5 or 10% FBS (** P < 0.01 compared with serum-free condition). (Reproduced from J. Kobayashi, D. Wigle, T. Childs, L. Zhu, F. W. Keeley, and M. Rabinovitch. Journal of Cellular Physiology 160: 121-131, 1994. Copyright 1994, John Wiley & Sons, Inc. Reprinted by permission of Wiley-Liss, Inc., a subsidiary of John Wiley & Sons, Inc.)

EVE is a powerful enzyme that, by virtue of its ability to degrade elastin, will also degrade proteoglycans that serve as storage sites for growth factors, such as basic fibroblast growth factor (FGF-2) and transforming growth factor-beta . A study from our laboratory (28) has shown that EVE releases FGF-2 in a biologically active form that stimulates SMC proliferation (Fig. 3).


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Fig. 3.   EVE-mediated release of 125I-bFGF into conditioned medium. Serum-starved ovine PASMCs preincubated with 125I-bFGF were exposed to serum-pretreated elastin (STE). STE treatment resulted in a concentration-dependent release of 125I-bFGF into conditioned medium. cpm, Counts/min. Values are means ± SD from 1 of 2 independent experiments with similar significance (* P < 0.05 compared with control levels). (Reproduced from K. Thompson and M. Rabinovitch. Journal of Cellular Physiology 166: 495-505, 1996. Copyright 1996, John Wiley & Sons, Inc. Reprinted by permission of Wiley-Liss, Inc., a subsidiary of John Wiley & Sons, Inc.)

Elastase activity either directly or via activation of matrix metalloproteinases can induce production of the matrix glycoprotein tenascin (TN) (17), which optimizes the mitogenic response to FGF-2 and is, in fact, a prerequisite for the response to epidermal growth factor (EGF) in cultured SMCs (13).

The process of SMC migration also appears to depend, at least in experimental animals, on the continued activity of elastase. We (7, 9) have shown that elastin peptides stimulate the production of the matrix glycoprotein fibronectin (FN), which changes SMCs from a contractile to a migratory phenotype, and we have begun to unravel a unique molecular mechanism of regulation.


    TN AND THE VASCULAR SMC PROLIFERATIVE RESPONSE
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ABSTRACT
INTRODUCTION
EVE AND PULMONARY VASCULAR...
TN AND THE VASCULAR...
FN AND THE VASCULAR...
APPLICATION TO SYSTEMIC ARTERY...
REFERENCES

We pursued the expression of TN in vascular disease by carrying out immunohistochemical analyses in biopsy tissue from patients with congenital heart defects. Minimal expression of TN was apparent with mild disease, but with progressive hypertrophy, intense foci were observed in the adventitia, periendothelium, and, occasionally, the media. With the development of obstructive lesions, TN colocalized in the neointima, with increased expression of EGF and proliferating cells as judged by positive immunostaining with an antibody that recognizes the proliferating cell nuclear antigen (11) (Fig. 4). A similar relationship was seen in the evolution of experimental pulmonary vascular disease. TN was apparent in the adventitia and outer media in PAs from rats 14 days after injection of monocrotaline, coincident with the development of pulmonary hypertension, and in the inner media and emerging neointima by day 21, associated with progressive disease and colocalization with proliferating cells. The morphological expression of TN is coupled with evidence of the induction of TN mRNA transcripts by Northern blot analysis (Fig. 5). Cultured rat SMCs showed that TN augmented the proliferative response to FGF-2 and was a prerequisite for the proliferative response to EGF (Fig. 6). The mechanism appears to involve a TN-mediated change in the cytoskeleton such that when TN is engaged by its integrin (alpha vbeta 3), actin filaments rearrange in focal adhesion contacts and EGF receptors are clustered and primed. The addition of EGF results in rapid phosphorylation of the EGF receptor and a cascade of phosphorylation events that results in a nuclear signal necessary for mitosis (12) (Fig. 7). On the other hand, complete withdrawal of TN results in SMC apoptosis.


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Fig. 4.   Representative photomicrographs showing immunoperoxidase staining for tenascin (TN)-C (A, D, and G), proliferating cell nuclear antigen (PCNA; B, E, and H), and epidermal growth factor (EGF; C, F, and I) in graded lung biopsy tissue sections. A-C: vessel showing a typical grade IA lesion. D-F: vessel showing a typical grade IC lesion. G-I: vessel showing a typical grade IIIC lesion. In low-grade lesions (A), modest TN immunostaining was evident in adventitia. With medial hypertrophy, TN immunoreactivity became more prominent in periendothelium (D), with the most intense immunostaining being apparent within neointima of high-grade lesions, showing occlusive neointimal formation (G). In lowest grade of lesion, PCNA was negative (B) despite foci of EGF in media. With medial hypertrophy, PCNA was expressed in media (E) together with foci of EGF (F). With development of higher-grade occlusive lesions, TN (G), PCNA (H), and EGF (I) colocalized to neointimal cell layers. Note that TN and PCNA staining was performed on serial sections, whereas EGF detection was carried out on similar vessels within the same biopsy. Original magnification, ×40. [Reproduced with permission from Jones et al. (11).]



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Fig. 5.   Northern blot analyses for TN in adult PA (A, top) and lung (A, bottom) tissue isolated at 7 (7d), 14 (14d), and 28 days (28d) post-monocrotaline injection. Two TN isoforms of ~6.4 and 7.3 kb were observed from 14 days postinjection in PA and from 7 days postinjection in lung tissue. 18S, 18S rRNA. B: densitometric analysis of 7.3-kb TN isoform from autoradiograms shown in A normalized to 28S rRNA loading controls showed that steady-state TN mRNA levels increase with progressive pulmonary vascular disease. [Reproduced with permission from Jones and Rabinovitch (13).]



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Fig. 6.   Effect of exogenous TN-C (15 g/ml) on PASMC attachment (A) and growth factor-dependent proliferation (B). No significant differences in attachment efficiency were noted between cells plated on type I collagen alone or on TN-C-supplemented gels (A). Similarly, SMC growth in serum-free medium (SFM) was unaffected by addition (+) of exogenous TN-C. In contrast, addition of bFGF or EGF to TN-C-treated cultures resulted in a significant increase in cell number. Values are means ± SE. * P < 0.05 vs. corresponding SFM level. dagger  P < 0.05 for difference related to TN-C.



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Fig. 7.   Hypothetical model for regulation and function of TN-C in vascular SMCs. A: vascular SMCs attach and spread on native type I collagen using beta 1-integrins. Under serum-free conditions, cells withdraw from cell cycle and become quiescent. EGF-R, EGF receptor. B: degradation of native type I collagen by matrix metalloproteinases (MMPs) leads to exposure of cryptic RGD sites that preferentially bind beta 3-subunit-containing integrins. In turn, occupancy and activation of beta 3-integrins signal production of TN-C. C: incorporation of multivalent TN-C protein into underlying substrate leads to further aggregation and activation of beta 3-containing integrins (avbeta 3) and to accumulation of tyrosine-phosphorylated (Tyr-P) signaling molecules and actin into a focal adhesion complex (FAC). Note that even in absence of EGF ligand, TN-C-dependent reorganization of cytoskeleton leads to clustering of actin-associated EGF-Rs. D: addition of EGF ligand to clustered EGF-Rs results in rapid and substantial tyrosine phosphorylation of EGF-R and activation of downstream pathways, culminating in generation of nuclear signals leading to cell proliferation. (Reproduced from P. L. Jones, J. Crack, and M. Rabinovitch. Journal of Cell Biology 139: 279-293, 1997, by copyright permission of the Rockefeller University Press.)


    FN AND THE VASCULAR SMC MIGRATORY RESPONSE
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ABSTRACT
INTRODUCTION
EVE AND PULMONARY VASCULAR...
TN AND THE VASCULAR...
FN AND THE VASCULAR...
APPLICATION TO SYSTEMIC ARTERY...
REFERENCES

To study how elastase may be related to SMC migration, we investigated the mechanism whereby fetal ductus arteriosus SMCs migrate during the formation of intimal cushions in late gestation. These structures partially occlude the ductus lumen and ensure that it completely closes in the postnatal period. We (33) had made the observation that the ductus, rather than degrading elastin, assembles elastin poorly. The by-products, namely the elastin peptides, convert the SMCs from contractile to migratory by upregulating their production of FN (7, 9). Ductus cells produce twofold more FN than aortic cells and appear quite different in collagen gels (1-3). They have an elongated "svelte" cometlike migratory phenotype compared with aortic cells, which appear more rotund and look like helicopters. By adding FN antibodies, the ductus cells revert to the contractile phenotype and lose their jetlike profile and property (Fig. 8). Conversely, when aortic SMCs are supplied with elastin peptides in the form of kappa -elastin or when they are induced to assemble elastin poorly and to produce elastin peptides through the addition of chondroitin sulfate (8), we (7, 9) have shown that they too upregulate their production of FN.


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Fig. 8.   Ductus arteriosus (DA) and aortic SMCs on collagen (2 mg/ml) gels. A: DA SMCs 2 days after being seeded onto surface of collagen gels. Cells exhibit a spindlelike elongated morphology, and majority of cells are visible on surface of gels. B: cell that has just migrated into gel. By focusing into gel at a depth of 250 µm, this cell comes clearly into focus. C: aortic cells 2 days after being seeded onto surface of gel exhibit a flattened, stellate morphology. In presence of antibodies against fibronectin (1:100), DA smooth muscle cells (D) also display a more flattened, stellate appearance. [Reprinted with permission from Boudreau et al. (3).]

The regulation of FN is posttranscriptional because there is no increase in FN mRNA levels as shown by Northern blot analysis (1). The mechanism is related to the more efficient translation of FN mRNA in the ductus SMCs compared with that in the aortic SMCs. This is related to the increased production of a microtubule-associated protein, LC3, that binds to a sequence in the 3'-untranslated region of FN mRNA rich in A+U bases (adenosine-uridine-rich element). We can increase the efficiency of translation of FN mRNA in aortic SMCs to produce levels of FN comparable to those in ductus cells by transfecting the aortic cells with LC3. Moreover, by sequestering LC3, we (32) have been able to switch the ductus phenotype to nonmigratory and prevent the increased production of FN that is associated with the migratory phenotype. A more recent study from our laboratory (16) has indicated that the production of LC3 may be a function of the redox state and intracellular concentration of nitric oxide.


    APPLICATION TO SYSTEMIC ARTERY DISEASE
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ABSTRACT
INTRODUCTION
EVE AND PULMONARY VASCULAR...
TN AND THE VASCULAR...
FN AND THE VASCULAR...
APPLICATION TO SYSTEMIC ARTERY...
REFERENCES

The mechanisms elucidated by the above studies will, we hope, lead to new therapeutic targets to prevent the progression of pulmonary vascular disease and potentially even to induce its regression. The windfall of our efforts has come through the extrapolation of our findings to coronary artery disease. This new direction of our laboratory was motivated by the loss of one of the pediatric heart transplant patients to an accelerated form of atherosclerosis. Using experimental models, we showed that elastase activity is high in coronary arteries after transplant and that this activity could be inhibited by exogenous elafin (23). The mechanism of graft coronary artery disease involved the infiltration of inflammatory cells and the consequent release of elastases and cytokines that interacted to induce SMC proliferation and FN-dependent migration (4, 5, 18-20). To test the effect of elastase in the pathophysiology of posttransplant-accelerated coronary arteriopathy, the elastase inhibitor elafin was given by continuous intravenous administration to rabbits after heterotopic heart transplantation. Elafin markedly reduced the number and severity of coronary artery intimal lesions (6) (Fig. 9). A dividend in these studies is that elafin also reduced the myocardial necrosis associated with transplant rejection, presumably by inhibiting T-cell elastase.


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Fig. 9.   Representative photomicrographs of Movat pentachrome staining of coronary arteries in host control and elafin-treated donor groups. Normal-appearing host vessel (A) contrasts with affected donor vessel (B), showing a concentric intimal lesion in control group, but a more normal-appearing artery is seen in elafin-treated donor group (C). Original magnification, ×200. (Reproduced from B. Cowan, O. Baron, J. Crack, C. Coulber, G. J. Wilson, and M. Rabinovitch. The Journal of Clinical Investigation 97: 2452-2468, 1996, by copyright permission of The American Society for Clinical Investigation.)


    ACKNOWLEDGEMENTS

M. Rabinovitch is a Heart and Stroke Foundation of Ontario Research Endowed Chair.


    FOOTNOTES

1 Reference 27 as well as Refs. 6, 11-13, 16, and 32 were published after the Julius Comroe Lecture was given at the Experimental Biology meeting in 1996.

This lecture was part of the Distinguished Lectureship Series given at the Experimental Biology meeting in 1996 in Washington, DC.

Address for reprint requests and other correspondence: M. Rabinovitch, Division of Cardiovascular Research, Hospital for Sick Children, 555 University Ave., Toronto, ON, Canada M5G 1X8 (E-mail: mr{at}sickkids.on.ca).


    REFERENCES
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ABSTRACT
INTRODUCTION
EVE AND PULMONARY VASCULAR...
TN AND THE VASCULAR...
FN AND THE VASCULAR...
APPLICATION TO SYSTEMIC ARTERY...
REFERENCES

1.   Boudreau, N., N. Clausell, J. Boyle, and M. Rabinovitch. Transforming growth factor-beta regulates increased ductus arteriosus endothelial glycosaminoglycan synthesis and a post-transcriptional mechanism controls increased smooth muscle fibronectin, features associated with intimal proliferation. Lab. Invest. 67: 350-359, 1992[Medline].

2.   Boudreau, N., and M. Rabinovitch. Developmentally regulated changes in extracellular matrix in endothelial and smooth muscle cells in the ductus arteriosus may be related to intimal proliferation. Lab. Invest. 64: 187-199, 1991[Medline].

3.   Boudreau, N., E. Turley, and M. Rabinovitch. Fibronectin, hyaluronan and a hyaluronan binding protein contribute to increased ductus arteriosus smooth muscle cell migration. Dev. Biol. 143: 235-247, 1991[Medline].

4.   Clausell, N., S. Molossi, S. Sett, and M. Rabinovitch. In vivo blockade of tumor necrosis factor-alpha in cholesterol-fed rabbits after cardiac transplant inhibits acute coronary artery neointimal formation. Circulation 89: 2768-2779, 1994[Abstract].

5.   Clausell, N., and M. Rabinovitch. Upregulation of fibronectin synthesis by interleukin-1beta in coronary artery smooth muscle cells is associated with the development of the post-cardiac transplant arteriopathy in piglets. J. Clin. Invest. 92: 1850-1858, 1992.

6.   Cowan, B., O. Baron, J. Crack, C. Coulber, G. J. Wilson, and M. Rabinovitch. Elafin, a serine elastase inhibitor, attenuates post-cardiac transplant coronary arteriopathy and reduces myocardial necrosis in rabbits following heterotopic cardiac transplantation. J. Clin. Invest. 97: 2452-2468, 1996[Abstract/Free Full Text].

7.   Hinek, A., J. Boyle, and M. Rabinovitch. Vascular smooth muscle cell detachment from elastin and migration through elastic laminae is promoted by chondroitin sulfate-induced "shedding" of the 67-kDa cell surface elastin binding protein. Exp. Cell Res. 203: 344-353, 1992[Medline].

8.   Hinek, A., R. P. Mecham, F. Keeley, and M. Rabinovitch. Impaired elastin fiber assembly related to reduced 67-kD elastin-binding protein in fetal lamb ductus arteriosus and cultured aortic smooth muscle cells treated with chondroitin sulfate. J. Clin. Invest. 88: 2083-2094, 1991[Medline].

9.   Hinek, A., S. Molossi, and M. Rabinovitch. Functional interplay between interleukin-1 receptor and elastin binding protein controls fibronectin synthesis in coronary artery smooth muscle cells. Exp. Cell Res. 225: 122-131, 1996[Medline].

10.   Hornebeck, W., J. C. Derouette, and L. Robert. Isolation, purification, and properties of aortic elastase. FEBS Lett. 58: 66-70, 1975[Medline].

11.   Jones, P. L., K. N. Cowan, and M. Rabinovitch. Tenascin-C, proliferation and subendothelial fibronectin in progressive pulmonary vascular disease. Am. J. Pathol. 150: 1349-1360, 1997[Abstract].

12.   Jones, P. L., J. Crack, and M. Rabinovitch. Regulation of tenascin-C, a vascular smooth muscle cell survival factor that interacts with the alpha vbeta 3 integrin to promote epidermal growth factor receptor phosphorylation and growth. J. Cell Biol. 139: 279-293, 1997[Abstract/Free Full Text].

13.   Jones, P. L., and M. Rabinovitch. Tenascin-C is induced with progressive pulmonary vascular disease in rats and is functionally related to increased smooth muscle cell proliferation. Circ. Res. 79: 1131-1142, 1996[Abstract/Free Full Text].

14.   Kobayashi, J., D. Wigle, T. Childs, L. Zhu, F. W. Keeley, and M. Rabinovitch. Serum-induced vascular smooth muscle cell elastolytic activity through tyrosine kinase intracellular signalling. J. Cell. Physiol. 160: 121-131, 1994[Medline].

15.   Maruyama, K., C. Ye, M. Woo, H. Venkatacharya, L. D. Lines, M. M. Silver, and M. Rabinovitch. Chronic hypoxic pulmonary hypertension in rats and increased elastolytic activity. Am. J. Physiol. 261 (Heart Circ. Physiol. 30): H1716-H1726, 1991[Abstract/Free Full Text].

16.  Mason, C. A. E., P. Chang, C. Fallery, and M. Rabinovitch. Nitric oxide mediates LC-3 dependent regulation of fibronectin synthesis in ductus arteriosus smooth muscle cells. FASEB J. In press.

17.   Meiners, S., M. Marone, J. L. Rittenhouse, and H. M. Geller. Regulation of astrocytic tenascin by basic fibroblast growth factor. Dev. Biol. 160: 480-493, 1993[Medline].

18.   Molossi, S., N. Clausell, and M. Rabinovitch. Reciprocal induction of tumor necrosis factor-alpha and interleukin-1beta activity mediates fibronectin synthesis in coronary artery smooth muscle cells. J. Cell. Physiol. 163: 19-29, 1995[Medline].

19.   Molossi, S., M. Elices, T. Arrhenius, R. Diaz, C. Coulber, and M. Rabinovitch. Blockade of very late antigen-4 integrin binding to fibronectin with connecting segment-1 peptide reduces accelerated coronary arteriopathy in rabbit cardiac allografts. J. Clin. Invest. 95: 2601-2610, 1995[Medline].

20.   Molossi, S., M. Elices, T. Arrhenius, and M. Rabinovitch. Lymphocyte transendothelial migration toward smooth muscle cells in interleukin-1beta stimulated co-cultures is related to fibronectin interactions with alpha 4beta 1 and alpha 5beta 1 integrins. J. Cell. Physiol. 164: 620-633, 1995[Medline].

21.   Nara, K., K. Ito, T. Ito, Y. Suzuki, M. A. Ghoneim, S. Tachibana, and S. Hirose. Elastase inhibitor elafin is a new type of proteinase inhibitor which has a transglutaminase-mediated anchoring sequence termed "cementoin". J. Biochem. (Tokyo) 115: 441-448, 1994[Abstract].

22.   Nuchprayoon, I., S. Meyers, L. M. Scott, J. Suzow, S. W. Hiebert, and A. D. Friedman. PEBP2/CBF, the murine homolog of the human myeloid AML1 and PEBP2beta CBF beta proto-oncoproteins, regulates the murine myeloperoxidase and neutrophil elastase genes in immature myeloid cells. Mol. Cell. Biol. 14: 5558-5568, 1994[Abstract].

23.   Oho, S., and M. Rabinovitch. Post-cardiac transplant arteriopathy in piglets is associated with fragmentation of elastin and increased activity of a serine elastase. Am. J. Pathol. 145: 202-210, 1994[Abstract].

24.   Rabinovitch, M., T. Bothwell, B. N. Hayakawa, W. G. Williams, G. A. Trusler, R. D. Rowe, P. M. Olley, and E. Cutz. Pulmonary artery endothelial abnormalities in patients with congenital heart defects and pulmonary hypertension: a correlation of light with scanning electron microscopy and transmission electron microscopy. Lab. Invest. 55: 632-653, 1986[Medline].

25.   Sallenave, J.-M., A. Silva, M. E. Marsden, and A. P. Ryle. Secretion of mucous proteinase inhibitor and elafin by Clara cell and type II pneumocyte cell lines. Am. J. Respir. Cell Mol. Biol. 8: 126-133, 1993[Medline].

26.   Schalkwijk, J., A. Chang, P. Janssen, G. J. de Jongh, and P. Mier. Skin-derived antileucoproteases (SKALPs): characterization of two new elastase inhibitors from psoriatic epidermis. Br. J. Dermatol. 122: 631-641, 1990[Medline].

27.   Thompson, E., J. Kobayashi, T. Childs, D. Wigle, and M. Rabinovitch. Endothelial and serum factors which include apolipoprotein A1 tether elastin to smooth muscle cells inducing serine elastase activity via tyrosine kinase-mediated transcription and translation. J. Cell. Physiol. 174: 78-89, 1998[Medline].

28.   Thompson, K., and M. Rabinovitch. Exogenous leukocyte and endogenous elastases can mediate mitogenic activity in pulmonary artery smooth muscle cells by release of extracellular matrix-bound basic fibroblast growth factor. J. Cell. Physiol. 166: 495-505, 1995.

29.   Todorovich-Hunter, L., H. Dodo, C. Ye, L. McCready, F. W. Keeley, and M. Rabinovitch. Increased pulmonary artery elastolytic activity in adult rats with monocrotaline-induced progressive hypertensive pulmonary vascular disease compared with infant rats with nonprogressive disease. Am. Rev. Respir. Dis. 146: 213-223, 1992[Medline].

30.   Wigle, D., K. Thompson, S. Yablonsky, P. L. Jones, S. Zaidi, C. Coulber, and M. Rabinovitch. AML1-like transcription factor induces serine elastase activity in ovine pulmonary artery smooth muscle cells. Circ. Res. 83: 252-263, 1998[Abstract/Free Full Text].

31.   Ye, C., and M. Rabinovitch. Inhibition of elastolysis by SC-37698 reduces development and progression of monocrotaline pulmonary hypertension. Am. J. Physiol. 261 (Heart Circ. Physiol. 30): H1255-H1267, 1991[Abstract/Free Full Text].

32.   Zhou, B., N. Boudreau, C. Coulber, J. Hammarback, and M. Rabinovitch. Microtubule-associated protein 1 light chain 3 is a fibronectin mRNA-binding protein linked to mRNA translation in lamb vascular smooth muscle cells. J. Clin. Invest. 100: 3070-3082, 1997[Abstract/Free Full Text].

33.   Zhu, L., E. Dagher, D. J. Johnson, D. Bedell-Hogan, F. W. Keeley, H. M. Kagan, and M. Rabinovitch. A developmentally regulated program restricting insolubilization of elastin and formation of laminae in the fetal lamb ductus arteriosus. Lab. Invest. 68: 321-331, 1993[Medline].

34.   Zhu, L., D. Wigle, A. Hinek, J. Kobayashi, C. Ye, M. Zuker, H. Dodo, F. W. Keeley, and M. Rabinovitch. The endogenous vascular elastase that governs development and progression of monocrotaline-induced pulmonary hypertension in rats is a novel enzyme related to the serine proteinase adipsin. J. Clin. Invest. 94: 1163-1171, 1994[Medline].


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