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Arteriosclerosis, Thrombosis, and Vascular Biology. 2000;20:2184-2191

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(Arteriosclerosis, Thrombosis, and Vascular Biology. 2000;20:2184.)
© 2000 American Heart Association, Inc.


Vascular Biology

Determination of Temporal Expression Patterns for Multiple Genes in the Rat Carotid Artery Injury Model

Julie T. N. Tai; Eric E. Brooks; Shoudan Liang; Roland Somogyi; Jose D. Rosete; Richard M. Lawn; Dov Shiffman

From CV Therapeutics (J.T.N.T., E.E.B., J.D.R., R.M.L., D.S.) and Incyte Pharmaceuticals (S.L., R.S.) Palo Alto, Calif.

Correspondence to Dr Dov Shiffman, CV Therapeutics, 3172 Porter Dr, Palo Alto, CA 94304. E-mail ds{at}cvt.com


*    Abstract
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Abstract—Vascular injury induces extensive alteration to the extracellular matrix (ECM). These changes contribute to lesion formation and promote cell migration and proliferation. To elucidate ECM response to arterial injury, we used real-time polymerase chain reaction monitoring to quantitate the expression levels of 81 genes involved in the synthesis and breakdown of ECM as well as receptors and signaling proteins that communicate and respond to ECM molecules. The temporal regulation of gene expression in the carotid was measured at 1, 3, 5, 7, 9, 14, and 28 days postinjury. Among the 68 genes that showed detectable expression by our method, 47 (69%) were significantly induced or repressed over time, confirming the extensive ECM gene response in this model. More ECM-related genes (31) were regulated at day 1 than at any other time point, and the number of regulated genes decreased over time. However, 14 of the genes were still induced or repressed at day 28, indicating that return to preinjury expression patterns did not occur and no new steady state was achieved over 28 days. In spite of the large number of changes in gene expression, only a small number of expression patterns was observed, suggesting that ECM-related genes could potentially be coregulated.


Key Words: restenosis • carotid artery injury • gene expression profiling • extracellular matrix • matrix metalloproteinases


*    Introduction
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*Introduction
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Restenosis, defined as recurrent lumen narrowing, is a significant clinical problem that occurs in 20% to 50% of patients undergoing percutaneous transluminal angioplasty.1 2 In the rat carotid balloon injury model of restenosis, the replication of smooth muscle cells in the tunica media is considered the initial wave of response that occurs during the first 2 days postinjury.3 Replication is followed by migration of smooth muscle cells from their normal location in the tunica media to the newly formed intimal layer. The subsequent proliferation of intimal smooth muscle cells eventually leads to the formation of a thickened neointima and consequent reduction in luminal diameter. Cell proliferation and migration events are promoted by the continuous breakdown and synthesis of a complex network of extracellular matrix (ECM) macromolecules that shape the vascular structure. It has been argued that although proliferation results in an increase of the total cell number, it is the ECM that accounts for the bulk of the neointimal volume in the restenotic lesion.4

Previous research has shown that ECM genes are significantly regulated after injury in the rat model and are responsive to numerous growth factors, cytokines, and stretch stimulation.5 However, expression studies using conventional methods usually generate information on a limited number of genes and fail to give a more comprehensive view of the transcriptional events governing these changes. Recently, it has been proposed6 7 8 9 that temporal transcription profiles of multiple genes during a model physiological process could be measured and clustered on the basis of similarities in their expression patterns.10 This information could potentially be used to propose regulatory circuits that control gene expression in the model system.11

Using real-time polymerase chain reaction (PCR) monitoring, we determined the expression profiles of 68 genes over 28 days in the rat carotid balloon injury model. The clustering of the temporal expression patterns of these genes yielded 4 waves of differential regulation, 1 of which could be additionally divided into 4 smaller clusters. More genes were regulated at 1 day after injury than at any other time point, and no new equilibrium was reached as late as 28 days postinjury. This systematic approach also led to the identification of genes previously not known to take part in neointima formation and could provide additional insight into the pathophysiology of the disease.


*    Methods
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Rat Tissue and RNA Isolation
Male Sprague-Dawley rats (400 to 500 g) (Charles River Breeding Laboratories, Wilmington, Mass) were anesthetized with an intraperitoneal injection of 0.45 to 0.55 mL of 58% ketamine and 42% xylazine mixture. A 2 French Fogarty catheter was used to induce vascular injury, as previously described.12 Rat neonatal smooth muscle cells were cultured, as described previously.12 RNA was extracted from pools of 10 carotid arteries or cultured smooth muscle cells using RNA STAT-60 (Tel-Test, Inc.) according to the instructions by the manufacturer and stored at -80°C.

mRNA Quantitation
Quantitation of gene expression was performed on the ABI Prism Sequence Detection System 5700 (PE Applied Biosystems). A set of primers was designed for each gene using Primer Express (PE Applied Biosystems). DNA sequence was obtained from GenBank (see online supplement at www.ahajournals.org), and amplicons of 100 to 200 base pairs with melting temperature between 68° and 85°C were selected. Reverse transcriptase (RT) reactions consisted of 0.1 to 1 µg of DNase-treated total RNA, 5.5 mmol/L of magnesium chloride, 500 µmol/L each of dNTP, 2.5 µmol/L of random hexamers, 0.4 U/µL of RNase inhibitor, and 2.5 µL of 50 U/µL MultiScribe RT in a final volume of 100 µL. The reaction conditions were 25°C for 10 minutes followed by 48°C for 30 minutes and inactivation at 95°C for 5 minutes. An aliquot of the RT reaction was used for a 40-cycle PCR amplification in the presence of SYBR green fluorescent dye according to a protocol provided by the manufacturer (PE Applied Biosystems). PCR product generation was monitored by measuring the increase in fluorescence caused by the binding of SYBR green to double-stranded DNA at each annealing phase. A dissociation curve was generated at the end of the 40th cycle to verify that a single product was amplified. A standard curve for each amplicon was obtained using serial dilutions of total RNA prepared from rat vascular smooth muscle cells grown in culture.

Data Analysis
The results from duplicate PCR reactions for a given gene in each time point were used to determine its RNA quantity relative to the corresponding standard curve. Two sets of PCR reactions, each with cyclophilin A13 or ribosomal protein S9 primers, were performed for each batch of RT reaction. The relative RNA quantity for a given gene sampled from the same RT reaction was divided by the value obtained for either of these 2 genes to correct for fluctuations in input RNA levels and varying efficiencies of RT reactions. The differential expression curves obtained using either of these genes as the correction factor consistently showed the same pattern.

Clustering
Each measurement was converted to the log2 of the ratio of injured over control sample for each time point (1, 3, 5, 7, 9, 14, and 28 days after injury), generating 7 expression ratio values for each gene. Considering that our data represent a time series, we were interested in the variation from one time point to the next. To emphasize these changes for clustering, the expression differences between consecutive time points were calculated. Consequently, the expression pattern for each gene was converted into a vector with 7 expression ratios and 6 expression differences. The Euclidean distance between these vectors was used as a similarity measure for the expression responses.

An iterative agglomerative algorithm of N-1 steps (N=number of genes) was used to construct a dendrogram similar to the phylogenetic tree familiar to most biologists.8 14 Starting with N clusters containing a single gene, at each step in the iteration the 2 closest clusters were merged into a larger cluster. The distance between clusters was defined as the distance between their average expression patterns. After N-1 steps, all the data points were merged together. This clustering process defines a hierarchical tree.

We can automatically assign genes to a cluster by cutting the tree between the root and each gene branch with a set of lines separated by equal distance (see Branch Levels in Figure 2DownDown). We first normalize the tree so that each branch is at the same distance from the root. To preserve the distance between the closest genes, we distort the tree at the branch farthest from the leaf. The number of intersections at each branch level determines the number of the grouping in that hierarchy.



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Figure 2. Clustering of gene expression data. A, Gene expression time series were clustered using an agglomerative algorithm, as described in the text. The numerical classifier on the left signifies the position of each gene in the similarity tree (dendrogram), which has been divided into 10 levels of branching depth. The black line between the numerical classifiers extends to the branch level in the tree at which the expression patterns of neighboring genes differ; a longer line corresponds to a bigger difference between neighboring expression profiles. For each gene, the log2 values of the expression ratio between injured and uninjured vessel at each time point are listed. As a visual aid, the expression data are accentuated by 4 levels of gray, ranging from the minimum (white) to the maximum (black) value for each gene. Alternating gray and white shading of gene names corresponds to the different clusters generated by cutting the tree at branch level 5. Wave numbers as they appear in the text are listed on the right. B, Subclusters of wave 1 generated by cutting the similarity tree at branch level 8.



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Figure IG2B. Continued.


*    Results
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mRNA Quantitation Using Real Time PCR Monitoring
The relative abundance of individual mRNA species was measured by RT-PCR, as described in Methods. Two potential sources of measurement errors are associated with real-time PCR monitoring. First, fluctuations in the quantity of input RNA and the varying efficiency of different RT reactions can affect the initial amount of cDNA in the PCR reaction. Second, the stochastic nature of the early cycles of PCR reactions can spuriously amplify small differences between samples. To reduce the noise level in this study, we normalized the message abundance with an internal control gene. It is important to choose a gene that shows a constant level of expression across all experimental conditions. Traditionally used housekeeping genes (glyceraldehyde-3-phosphate dehydrogenase and {alpha}-actin) failed to meet this criterion. We found that the expression level ratios of cyclophilin A and ribosomal protein S9 were consistent in all of our experimental samples, indicating that these genes are either tightly coregulated or, more probably, expressed at constant levels (data not shown). To evaluate the measurement errors in our study, we measured the quantity of 16 mRNA species twice, using a pair of independent RT-PCR reactions of the same sample. For most of the genes (75%), a 1- to 2.4-fold change was measured (Figure 1Down), indicating that a measured 2.4-fold change or less between samples was not reliable enough to indicate a real difference. The results of duplicated PCR reactions taken from the same RT reactions were more reproducible (<26% SD), suggesting that the variation was mainly attributable to differences in the efficiency of independent RT reactions. On the basis of these results, a 2.5-fold differential expression was considered a significant change. This cutoff level was a compromise between inclusion of data that are within the measurement error (false positives) and exclusion of genes that are regulated at low levels (false negatives).



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Figure 1. Real-time PCR reproducibility. Fold changes in the normalized values of 16 genes obtained from 2 independent RT-PCR reactions were calculated. Five genes had a 1- to 1.4-fold change between these measurements, 4 had a 1.5- to 1.9-fold change, 3 had a 2- to 2.4-fold change, and 4 had a 2.5- and 3.2-fold change.

Genes Surveyed in the Study
A list of 81 known rat genes was compiled for the study (Table 1DownDown) (for a complete list online of accession numbers and primers used, please see www.ahajournals.org). It included components of the vascular matrix, their corresponding receptors, enzymes involved in matrix remodeling, and the family of transforming growth factor (TGF)-ß cytokines and their receptors. Several cell-cycle progression markers were also included. Some of the genes are known to be regulated in this model. However, to systematically analyze the regulation of all the ECM components, we also included genes not reported or expected to be expressed in the carotid artery, such as aggrecan and neurocan. The temporal expression profiles of all 81 genes were initially analyzed at 4 time points: 1, 3, 7, and 14 days postinjury, because it has been observed that key events of cell migration proliferation occur during this period of time. Thirteen of the 81 genes were not detectable either in normal or injured carotid tissue by our method. Although it is possible that these genes are expressed at other time points after injury, they were excluded from subsequent analysis, because the information obtained would not be sufficient to generate a complete temporal expression profile. The remaining 68 genes were then measured at a higher sampling density (1, 3, 5, 7, 9, 14, and 28 days postinjury).


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Table 1. Rat Genes Analyzed by Real Time Quantitative RT-PCR


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Table AB1A. Continued

Global Expression Changes
A total of 47 (69%) of the genes showed 2.5-fold differential expression at one or multiple time points (Figure 2Up) (log2 values >1.3 or <-1.3). The largest number of differentially regulated genes was observed at the first day postinjury. Thirty-one genes were found to be at least 2.5-fold upregulated or downregulated at this time (Figure 3Down). Downregulated genes (21) outnumbered the upregulated genes (10). The number of differentially regulated genes decreased at later time points, a trend indicating a partial return to steady state. However, even at day 28, 14 of the genes (20%) were differentially regulated, indicating an ongoing process of ECM modulation.



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Figure 3. Temporal differential expression plot. Numbers of genes that are significantly induced (open bars) or repressed (black bars) at each time point are plotted.

Cluster Analysis
The expression profiles were clustered on the basis of similarities in the trend and magnitude of the differential expression pattern. The data were normalized using the log2 values of the expression levels ratio between the injured and the normal arteries at each time point. The magnitude of the normalized change and the slope of the curve were weighted when a dendrogram of the expression profiles was generated (see Methods). Each gene was assigned a numerical tag, which corresponded to the branching pattern for that gene. Thus, genes can be clustered at different levels of similarity using this tag (Figure 2Up). Four clusters were generated by cutting the expression profile tree at branch level 5 (Figure 2AUp). Waves 1 and 4 consisted of 40 genes, accounting for 85% of the differentially regulated genes. Thus, the expression profiles of a vast majority of the surveyed genes can be captured in these 2 clusters. Genes in wave 1 can be additionally segmented into 4 distinct groups by cutting the clustering tree at branch level 8 (Figure 2BUp), resulting in a total of 7 waves of expression profiles (Figure 4Down). Waves 1.A through 1.D shared an early repression feature but had distinct characteristics in the timing and extent of differential regulation. Genes in wave 1.A were moderately repressed from days 1 to 5, whereas the genes in wave 1.C were downregulated at days 1 and 3. The 3 genes in wave 1.D, collagen {alpha}1 type III, collagen {alpha}2 type V, and glypican, were sharply downregulated at day 1 only. Wave 1.B showed a unique pattern of downregulation at day 1 and upregulation at day 9. Altogether, wave 1 comprised the largest number (25) of differentially regulated genes and, therefore, can be considered the predominant regulation trend for ECM genes in this model. Several genes in wave 1 belong to the group of late matrix components: 4 collagens, 7 proteoglycans, and 1 elastin. The expression pattern of some of these genes has been previously described15 16 and largely corresponds to our data, but these results were interpreted only as a late induction of these genes, and very little was reported regarding their early regulation. Waves 2 and 3 represented two opposite trends of induction. They deviated from other genes in the cluster tree at branch level 1 and 3, suggesting that their expression profiles are distinctively different from other clusters. The 3 genes in wave 2 showed peak induction at day 1 (Figure 4Down). Matrix metalloproteinase-8 (MMP-8) is a neutrophil-derived matrix metalloproteinase, and its early upregulation might be indicative of early neutrophil adhesion in this model. Early neutrophil adhesion has been reported in similar injury models of rabbit17 and mouse.18 Wave 3 also consisted of only 3 genes: tenascin-C, aggrecan, and MMP-12. They were all significantly and continuously induced until day 28. This group of genes also showed the greatest increase in its expression level, because an average of 42-fold induction over normal was observed at day 7 (Figure 4Down). Wave 4 can be characterized by intermediate induction from days 3 to 7. It has been reported that genes involved in cell proliferation and hyaluronic acid (HA)-mediated motility are induced between 3 to 7 days postinjury in this model.19 20 21 Not surprisingly, 2 genes involved in the regulation of cell-cycle progression, cyclin-dependent kinase 1 (CDK1) and cyclin B, and 3 members of the HA family, HA synthase, CD44, and receptor for hyaluronan-mediated motility (RHAMM), are among the genes clustered in wave 4 (Figure 4Down). Some of the genes in this cluster were not significantly induced between days 3 and 7. For example, versican V3 isoform is only significantly upregulated at day 1. However, the clustering algorithm is designed to capture both the shape of the curve and magnitude of change. The change in expression for versican V3 isoform between days 3 and 9 generated a shape characteristic of wave 4, even though the data points were within the noise level. Therefore, clustering data should be examined critically, taking into account the limitations of the method and noise level in the data. One gene, sciatic nerve integrin ß, displayed unique expression profiles and did not cluster into any of the 7 waves described above (Figure 2AUp).



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Figure 4. Waves of differential expression. Normalized gene expression profiles from Figure 2Up were cut at level 5 to generate 4 major waves of differential expression. Wave 1 was additionally analyzed at level 8 to yield 4 subwaves. Normalized expression patterns over 7 time points for all genes in each wave are shown in dotted gray lines, with the average expression pattern for each wave in heavy lines. Genes in wave 1.A: syndecan-3, tissue inhibitor of MMP-3 (TIMP-3), and plasminogen activator inhibitor-1 (PAI-1); genes in wave 1.B: biglycan, TGF-ß2, lysyl oxidase, and p21; genes in wave 1.C: agrin, syndecan-2, MMP-2, MMP-11, membrane-type 3 (MT3)-MMP, TIMP-2, collagen {alpha}2 type I, TGF-ß3, collagen {alpha}1 type I, integrin ß5, MMP-21/23, lumican, MT1-MMP, tropoelastin, and decorin; genes in wave 1.D: collagen {alpha}1 type III, collagen {alpha}2 type V, and glypican; genes in wave 2: integrin ß7, PAI-2, and MMP-8; genes in wave 3: aggrecan, tenascin-C, and MMP-12; genes in wave 4: CD 44, osteopontin, urokinase plasminogen activator (uPA) receptor, uPA, HA synthase, syndecan-1, fibronectin, TIMP-1, versican V3 isoform, CDK1, cyclin B, RHAMM, collagen {alpha}1 type XII, and thrombospondin-4.


*    Discussion
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*Discussion
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We have successfully used real-time PCR to measure the expression fingerprints of the major ECM and representative cell-cycle control genes in the rat carotid artery restenosis model. Traditionally, RNA isolation posed a major limitation for gene expression studies in rat carotid arteries, because the tissue sections are small in size ({approx}10x2 mm) and have a high ECM content. Typically, pools of 5 to 10 carotids were needed to obtain enough RNA for a Northern blot analysis of a single gene. Because RT-PCR requires a small amount of RNA, 10- to 50-mRNA species can be measured from a single carotid (J.T., unpublished data, May 1999). This highly sensitive method allowed us to generate expression information for all but 13 of the genes analyzed.

The rat carotid artery is undergoing continuous alteration in tissue composition during the process of restenosis. Smooth muscle cell proliferation and immune cell invasion result in different proportions of adventitia, media, neointima, and invading immune cells when compared with normal carotid arteries at various time points. However , the changing composition of the tissue could additionally complicate data interpretation, because gene induction could be attributable to either an increase in the number of cells expressing a given gene in the injured tissue or to an increase in the expression level in a fixed population of cells. Thus, changes in expression of MMP-8 could either reflect early neutrophil adhesion or the induction of MMP-8 expression in the existing tissue. Although the presence of neutrophils in mice18 and rabbit17 arteries after injury was observed previously, the localization of these differential expression events awaits in situ hybridization analysis.

The systematic expression profiling of genes involved in ECM synthesis and response revealed an extensive differential regulation of these genes in the rat carotid balloon injury model. A total of 47 genes showed differential regulation of 2.5-fold from normal at one or multiple time points. The largest number of differentially regulated genes was observed at the earliest measurement, 1 day after injury. As the tissue is responding to the recent trauma generated by endothelial denudation and stretching, early changes in gene expression can be expected. Because we monitored only a small number of genes relative to the whole genome, it remains to be seen whether this pronounced early downregulation of gene expression will hold for a much larger sample of genes. It is apparent from our study that significant differential gene expression still persists 4 weeks after injury, even though smooth muscle cell proliferation and migration are believed to subside by 2 weeks in this model.22 A total of 14 genes were differentially regulated at 28 days postinjury. Previously, 4 other genes were reported to be regulated in similar time frame,23 which would suggest that the system does not return to the preinjury state.

The number of repressed versus induced genes decreases over time (Figure 3Up). At day 1, 21 genes were repressed and 10 were induced. By day 28, only 2 were repressed and 12 were induced. This trend could be attributed to the large number of ECM genes monitored in this study, because it has been shown that accumulation of ECM increases in the late phases of arterial repair in similar models.24 25 Our observation that more genes are induced at late time points is consistent with the roles these matrix components play in the injury response.

The measurement of the expression levels of numerous genes led to the identification of regulation events not recognized previously. For example, the inductions of cartilage oligomeric matrix protein (COMP), collagen {alpha}1 type XII, and aggrecan have not been documented in this model previously. Recently it has been shown that the expression of collagen {alpha}1 type XII and tenascin-C is induced by mechanical stress,26 27 and stretch-responsive enhancer regions were found in the promoters of these 2 genes.28 In our analysis, these genes showed significant induction by day 3 after injury, and both peaked at days 5 and 7. Because it is known that the accumulation of matrix proteins increases the tensile strength of the arterial wall after balloon injury,29 it is possible that the induction of these 2 genes in this model was in response to ECM synthesis.

Both COMP (a glycoprotein) and aggrecan (a chondrotin sulfate proteoglycan) are proteins found almost exclusively in the cartilage.30 31 The expression levels of COMP and aggrecan are low in normal carotid tissues and were induced 15- and 64-fold, respectively, at day 28 postinjury. Osteopontin, an acidic noncollagenous protein of the ECM of the cartilage, was also induced in our model (6-fold on day 3). Osteopontin is shown to be elevated after rat carotid injury,23 32 in human atherosclerotic plaques,33 and at sites of dystrophic calcification, and it may play a regulatory role in calcification.34 35 36 Because vascular calcification is a common finding in atherosclerosis and aortic stenosis, the induction of these 3 genes suggests a similar calcification process occurring in the rat restenosis model.

Clustering the expression profiles we measured can be used to generate new research questions. It is not surprising that most of the collagen genes we measured cluster together in wave 1; however, collagen {alpha}1 type XII has a different expression pattern (wave 4) and might indicate its different role in the restenosis process. Waves 2 and 3 were sharply different from the other genes we studied and branched off the hierarchical tree earlier than other clusters (Figure 2AUp). We do not know whether these 2 groups reflect distinct novel biological processes or whether the tight coregulation we observed for these 2 clusters is coincidental. Elucidating the transcription control mechanisms of genes in these clusters and identification of common regulatory factors could clarify the biological significance of these findings.

This study demonstrates the feasibility of expression analysis of nearly 100 genes in a complex tissue source with limiting amounts of RNA. The quantitative nature of our data allows easy comparison to expression information generated in other studies and makes it a useful database for expression profiles of ECM gene families in the rat injury model. Future experiments can assess the effects of pharmacological intervention on gene expression and provide a better understanding of drug effects in restenosis. The study is limited by the sensitivity of the method and by its noise level. However, our ability to detect a gene expressed primarily in neutrophils demonstrates the potential utility of our methodology. The number and profile of the clusters we observed also increased our confidence in the validity of our data, because the expression profiles we obtained were not random and did not include the entire spectrum of possible expression patterns.

Received April 3, 2000; accepted July 21, 2000.


*    References
up arrowTop
up arrowAbstract
up arrowIntroduction
up arrowMethods
up arrowResults
up arrowDiscussion
*References
 
1. Yntani C, Imakita M, Ishibashi-Ueda H, Tsukamoto Y, Nishida N, Ikeda Y. Coronary atherosclerosis and interventions: pathological sequences and restenosis. Pathol Int. 1999;49:273–290.[Medline] [Order article via Infotrieve]

2. Casterella PJ, Teirstein PS. Prevention of coronary restenosis. Cardiol Rev. 1999;7:219–231.[Medline] [Order article via Infotrieve]

3. Libby P, Tanaka H. The molecular bases of restenosis. Prog Cardiovasc Dis. 1997;40:97–106.[Medline] [Order article via Infotrieve]

4. Schwartz RS, Holmes DR, Topol EJ. The restenosis paradigm revisited: an alternative proposal for cellular mechanisms. J Am Coll Cardiol. 1992;20:1284–1293.[Abstract]

5. Gibbons GH, Dzau VJ. The emerging concept of vascular remodeling. N Eng J Med. 1994;330:1431–1438.[Free Full Text]

6. Lockhart DJ, Dong H, Byrne MC, Follettie MT, Gallo MV, Chee MS, Mittmann M, Wang C, Kobayashi M, Horton H, Brown EL. Expression monitoring by hybridization to high-density oligonucleotide arrays. Nat Biotechnol. 1996;14:1675–1680.[Medline] [Order article via Infotrieve]

7. Schena M, Shalon D, Heller R, Chai A, Brown PO, Davis RW. Parallel human genome analysis: microarray-based expression monitoring of 1000 genes. Proc Natl Acad Sci U S A. 1996;93:10614–10619.[Abstract/Free Full Text]

8. Wen X, Fuhrman S, Michaels GS, Carr DB, Smith S, Barker JL, Somogyi R. Large-scale temporal gene expression mapping of central nervous system development. Proc Natl Acad Sci U S A. 1998;95:334–339.[Abstract/Free Full Text]

9. Iyer VR, Eisen MB, Ross DT, Schuler G, Moore T, Lee JCF, Trent JM, Staudt LM, Hudson J Jr, Boguski MS, Lashkari D, Shalon D, Botstein D, Brown PO. The transcriptional program in the response of human fibroblasts to serum. Science. 1999;283:83–87.[Abstract/Free Full Text]

10. Eisen MB, Spellman PT, Brown PO, Botstein D. Cluster analysis and display of genome-wide expression patterns. Proc Natl Acad Sci U S A. 1998;95:14863–14868.[Abstract/Free Full Text]

11. D’haeseleer P, Liang S, Somogyi R. Genetic network inference: from co-expression clustering to reverse engineering. Bioinformatics. In press.

12. Brooks EE, Gray NS, Joly A, Kerwar SS, Lum R, Mackman RL, Norman TC, Rosete J, Rowe M, Schow SR, Schultz PG, Wang X, Wick MM, Shiffman D. CVT-313, a specific and potent inhibitor of CDK2 that prevents neointimal proliferation. J Biol Chem. 1997;272:29207–29211.[Abstract/Free Full Text]

13. Danielson PE, Forss-Petter S, Brow MA, Calavetta L, Doglass J, Milner RJ, Sutcliffe JG. p1B15: a cDNA clone of the rat mRNA encoding cyclophilin. DNA. 1988;7:261–267.[Medline] [Order article via Infotrieve]

14. Eisen JA. Phylogenomics: improving functional predictions for uncharacterized genes by evolutionary analysis. Genome Res. 1998;8:163–167.[Free Full Text]

15. Majesky MW, Lindner V, Twardzik DR, Schwartz SM, Reidy MA. Production of transforming growth factor ß1 during repair of arterial injury. J Clin Invest. 1991;88:904–910.

16. Jenkins GM, Crow MT, Bilato C, Gluzband Y, Ryu WS, Li Z, Stetler-Stevenson W, Nater C, Froehlich JP, Lakatta EG, Cheng L. Increased expression of membrane-type matrix metalloproteinase and preferential localization of matrix metalloporteinase-2 to the neointima of balloon-injured rat carotid arteries. Circulation. 1998;97:82–90.[Abstract/Free Full Text]

17. Welt FG, Edelman ER, Rogers C. Neutrophil, not macrophage, infiltration precedes neointimal thickening after endothelial denudation. Circulation. 1999;100(suppl I):I-541. Abstract.

18. Simon DI, Chen Z, Seifert P, Edelman ER, Ballantyne CM, Rogers C. Decreased neointimal formation in Mac-1-/- mice revealed a role for inflammation in vascular repair after angioplasty. J Clin Invest. 2000;105:293–300.[Medline] [Order article via Infotrieve]

19. Wei GL, Krasinski K, Kearney M, Isner JM, Walsh K, Andres V. Temporally and spatially coordinated expression of cell cycle regulatory factors after angioplasty. Circ Res. 1997;80:418–426.

20. Savani RC, Turley EA. The role of hyaluronan and its receptors in restenosis after balloon angioplasty: development of a potential therapy. Int J Tissue React. 1995;17:141–151.[Medline] [Order article via Infotrieve]

21. Riessen R, Wight TN, Pastore C, Henley C, Isner JM. Distribution of hyaluronan during extracellular matrix remodeling in human restenotic arteries and balloon-injured rat carotid arteries. Circulation. 1996;93:1141–1147.[Abstract/Free Full Text]

22. Clowes AW, Reidy MA, Clowes MM. Kinetics of cellular proliferation after arterial injury, I: smooth muscle growth in the absence of endothelium. Lab Invest. 1983;49:327–333.[Medline] [Order article via Infotrieve]

23. Adams LD, Lemire JM, Schwartz SM. A systematic analysis of 40 random genes in cultured vascular smooth muscle subtypes reveals a heterogeneity of gene expression and identifies the tight junction gene zonula occludens 2 as a marker of epithelioid "pup" smooth muscle cells and a participant in carotid neointimal formation. Atherioscler Thromb Vasc Biol. 1999;19:2600–2608.[Abstract/Free Full Text]

24. Lindner V, Fingerle J, Reidy MA. Mouse model of arterial injury. Circ Res. 1993;73:792–796.[Abstract/Free Full Text]

25. Fuster V, Badimon L, Badimon JJ, Chesebro JH. The pathogenesis of coronary artery disease and the acute coronary syndromes. N Engl J Med. 1992;326:242–250.[Medline] [Order article via Infotrieve]

26. Chiquet M, Matthisson M, Koch M, Tannheimer M, Chiquet-Ehrismann R. Regulation of extracellular matrix synthesis by mechanical stress. Biochem Cell Biol. 1996;74:737–744.[Medline] [Order article via Infotrieve]

27. Trachslin J, Koch M, Chiquet M. Rapid and reversible regulation of collagen XII expression by changes in tensile stress. Exp Cell Res. 1999;247:320–328.[Medline] [Order article via Infotrieve]

28. Chiquet M. Regulation of extracellular matrix gene expression by mechanical stress. Matrix Biol. 1999;18:417–426.[Medline] [Order article via Infotrieve]

29. Batchelor WB, Robinson R, Strauss BH. The extracellular matrix in balloon arterial injury: a novel target for restenosis prevention. Prog Cardiovasc Dis. 1998;41:35–49.[Medline] [Order article via Infotrieve]

30. Glumoff V, Savontaus M, Vehanen J, Vuorio E. Analysis of aggrecan and tenascin gene expression in mouse skeletal tissues by northern and in situ hybridization using species specific cDNA probes. Biochim Biophys Acta. 1994;1219:613–622.[Medline] [Order article via Infotrieve]

31. Hedbom E, Antonsson P, Hjerpe A, Aeschlimann D, Paulsson M, Rosa-Pimentel E, Sommarin Y, Wendel M, Oldberg A, Heinegard D. Cartilage matrix proteins: an acidic oligomeric protein (COMP) detected only in cartilage. J Biol Chem. 1992;267:6132–6136.[Abstract/Free Full Text]

32. Wang X, Louden C, Ohlstein EH, Stadel JM, Gu JL, Yue TL. Osteopontin expression in platelet-derived growth factor-stimulated vascular smooth muscle cells and carotid artery after balloon angioplasty. Atherioscler Thromb Vasc Biol. 1996;16:1365–1372.[Abstract/Free Full Text]

33. Giachelli CM, Bae N, Almeida M, Denhardt DT, Alpers CE, Schwartz SM. Osteopontin is elevated during neointima formation in rat arteries and is a novel component of human atherosclerotic plaques. J Clin Invest. 1993;92:1686–1696.

34. Ikeda T, Shirasawa T, Esaki Y, Yoshiki S, Hirokawa K. Osteopontin mRNA is expressed by smooth muscle-derived foam cells in human atherosclerotic lesions of the aorta. J Clin Invest. 1993;92:2814–2820.

35. Hirota S, Imakita M, Kohri K, Ito A, Morii E, Adachi S, Kim H-M, Kiamura Y, Yutani C, Nomura S. Expression of osteopontin messenger RNA by macrophages in atherosclerotic plaques: a possible association with calcification. Am J Pathol. 1993;143:1003–1008.[Abstract]

36. Fitzpatrick LA, Severson A, Edwards WD, Ingram RT. Diffuse calcification in human coronary arteries: association of osteopontin with atherosclerosis. J Clin Invest. 1994;94:1597–1604.




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