Biomedical subjects

N A Kefalides

Publications and source records attributed to N A Kefalides.

At least 19 recordsLinked to original sources

PubMed1994

The alpha 3 chain of type IV collagen prevents activation of human polymorphonuclear leukocytes.

Our initial observation that type I collagen activates polymorphonuclear leukocytes (PMN) prompted the testing of the activating potential of type IV collagen. It was noted, however, that type IV collagen isolated from bovine lens capsule did not activate PMN but rather prevented their stimulation by N-formylmethionyl-leucyl-phenylalanine, phorbol myristate acetate, or type I collagen. This observation led to the present study, which demonstrates that the inhibitory effect of lens capsule type IV collagen resides in the noncollagenous (NC1) domain of the alpha 3 chain and specifically in the region comprising residues 185-203 of the NC1 domain of both the human and bovine molecules. Synthetic peptides from the same region of the NC1 domains of the alpha 1, alpha 2, alpha 4, and alpha 5 chains did not possess the inhibitory effect seen with the alpha 3 chain. The sequence S-N-S (residues 189-191) is unique to the peptide of the alpha 3 chain, and substitution of either serine with alanine abolishes the inhibition. Type IV collagen isolated from the mouse Engelbreth-Holm-Swarm (EHS) tumor, a molecule that lacks the alpha 3 chain, did not prevent PMN activation but instead stimulated the secretion of elastase and type IV collagenase. Incubation of PMN with intact lens capsule type IV collagen or a peptide comprising residues 185-203 of the alpha 3 (IV) chain resulted in a 3-fold increase of intracellular cAMP, whereas, Ca2+ levels remained unchanged. Incubating PMN with forskolin or with dibutyryl-cAMP resulted in the inhibition of O2- production and degranulation by PMN, thus mimicking the effects of type IV collagen and the alpha 3 (IV) 185-203 peptide. The data suggest that type IV collagen, through its alpha 3 chain, down-regulates PMN activation and thus decreases the potential for damage as these cells traverse the capillary wall. Our in vitro experiments suggest that the higher the content of the alpha 3 (IV) chain is in a basement membrane, the wider would be its capacity for self-protection.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1994

Coculture modulates laminin synthesis and mRNA levels in epidermal keratinocytes and dermal fibroblasts.

To investigate the role of cell-cell interactions between keratinocytes and fibroblasts at the dermal-epidermal junction in the regulation of extracellular matrix protein expression, we have developed a cell coculture model that allows both cell types to interact on a reciprocal basis and yet be isolated as pure populations for quantitative analysis. Using porous membrane inserts as a substrate for keratinocytes grown in coculture over fibroblast monolayers, we report that coculture stimulates cell growth and total protein synthesis in both cell types when compared to monocultured controls. Both keratinocytes and fibroblasts synthesize laminin B1 and B2 chains with an additional subunit comigrating with laminin M chain detected in keratinocytes but only faintly visible in fibroblasts. Laminin A chain synthesis could not be detected. Although laminin subunit composition did not change in either cell type, fractional laminin synthesis increases by 41.0 +/- 2.3% in cocultured keratinocytes and decreases by 73.8 +/- 8.1% in cocultured fibroblasts when compared to monocultured controls. In cocultured keratinocytes, steady-state mRNA levels for laminin B1, B2, and M chains increased by 69.4, 63.5, and 136.8%, respectively, when compared to monocultured controls. However, in cocultured fibroblasts, laminin B1 and B2 chain mRNA decreased by 74.2 and 72.7%, respectively. Laminin M chain mRNA could not be detected in fibroblasts. These results suggest that synthesis and expression of laminin is regulated through reciprocal cell-cell interactions in fibroblasts and keratinocytes grown in coculture.

Cell Communication↗

PubMed1994

Expression of the alpha 2-subunit of laminin correlates with increased cell adhesion and metastatic propensity.

Previous studies have indicated that laminin from neoplastic cells of high tumorigenicity is less active in promoting cell adhesion than aminin from normal cells or tissues. In the present study, we tested the hypothesis that laminin of metastatic tumor cells differs from that of nonmetastatic cells. Accordingly, we determined the subunit composition of laminin in highly metastatic, ras-transformed cells (4R) and compared it with laminin produced by nonmetastatic cells transformed with ras plus E1a (RE4). Metastatic 4R cells produced three to four times more of the alpha 2-subunit of laminin than RE4 cells did. Furthermore, the highly metastatic human melanoma cells (1205 and A2058) made and secreted into the medium, laminin containing significantly more of the alpha 2-subunit than laminin from the highly tumorigenic but nonmetastatic melanoma WM793 or HT1080 fibrosarcoma cells. Using HT1080 cells, laminin (250 ng/well) from 4R cells showed more adhesion promoting activity (68%) than laminin from RE4 cells (39%). Similarly, laminin isolated from human placenta, which expresses both the alpha 1 beta 1 gamma 1 and alpha 2 beta 1 gamma 1 isoforms, promoted cell adhesion better (63%) than EHS laminin (26%), which contains only the former isoform, at 250 ng/well. In addition, both 4R and RE4 cells attached more efficiently to 4R laminin-coated substratum than to RE4 laminin at 0.3 and 0.6 microgram/well.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Lithium chloride suppresses the synthesis of messenger RNA for infected cell protein-4 and viral deoxyribonucleic acid polymerase in herpes simplex virus-1 infected endothelial cells.

BACKGROUND: Patients treated with lithium salts for manic depression had a lower incidence of herpes simplex infections. Initial studies in our laboratory demonstrated that addition of LiCl in cultures of human endothelial cells infected with herpes simplex virus suppressed viral replication and allowed synthesis of host proteins. EXPERIMENTAL DESIGN: Based on the above observations, we decided to study the optimal condition for the lithium effect and determine the process of inhibition of viral replication. Endothelial cell cultures infected with herpes simplex virus-1 were exposed to LiCl at various times postinfection. The levels of host and viral mRNAs were measured by Northern and slot blot hybridization. The pattern of protein synthesis was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot and replication was assessed by plaque assay. RESULTS: LiCl inhibited virus replication in a dose- and time-dependent manner as was reflected in the sharp decrease or absence of infectious virus production. The condition for optimal effects of LiCl were the addition of the salt between 0-3 hours postinfection, and at a concentration of 30 mM. LiCl suppressed the synthesis of viral polypeptides, whereas the synthesis of host proteins was maintained. Similar results were observed with phosphonoacetic acid, an inhibitor of viral DNA polymerase. NaCl, at the same concentration as LiCl, did not prevent the virus-induced inhibition of host cell protein synthesis. The level of host mRNA for fibronectin, thrombospondin, collagen type IV, actin, and plasminogen activator inhibitor-1 were maintained in the presence of LiCl. mRNAs for viral proteins, ICP-4 and DNA polymerase were nearly undetectable when LiCl was added with the virus (0 time postinfection). CONCLUSIONS: The data indicate that LiCl treatment results in suppression of herpes virus mRNAs, i.e., mRNAs for ICP-4 and DNA polymerase, thereby inhibiting replication. On the other hand, the levels of host mRNAs are maintained to varying degrees depending on the message. The data suggest that a very early step in the process of viral replication is affected by LiCl, since the drug is maximally effective when added with the virus.

Blotting, Northern↗

PubMed1993

Heterogeneity of antibodies in Goodpasture syndrome reacting with type IV collagen.

Sera from patients with antiglomerular basement membrane (anti-GBM) antibodies associated with Goodpasture syndrome (GP) or glomerulonephritis were tested by ELISA and electroimmunoblot against whole basement membrane collagen (type IV) isolated from bovine anterior lens capsule (ALC) and bacterial collagenase resistant domains of the collagen molecule, that is, the NC-1 and 7-S domains isolated from either ALC or bovine and human glomerular basement membrane (GBM). Reactivity was high with the NC-1 domain by both the ELISA and the electroimmunoblot techniques. Some of the anti-GBM sera reacted with both the NC-1 and 7-S domains of both human and bovine type IV collagen. At a time when the patients' sera reacted weakly with a collagenase digest of human GBM using a radioimmunoassay, the reactivity with the NC-1 domain was also low, but some of the sera continued to react with the 7-S domain. The data suggest that there may be heterogeneity in the nature of autoantibodies with respect to collagen type IV domain reactivity in the sera of patients with anti-GBM antibody disease.

Animals↗

PubMed1993

Identification of antigenic epitopes in type IV collagen by use of synthetic peptides.

Peptides representing potential antigenic regions of the NC-1 and 7-S domains of the human alpha 1 and alpha 2, and bovine alpha 3 chains of type IV collagen were synthesized either chemically or by the recombinant DNA technique and tested by ELISA using antibodies raised in rabbits against the whole type IV collagen or the NC-1 domain. Sera from patients with Goodpasture syndrome (GP) or with acute poststreptococcal glomerulonephritis (APSGN) were also tested. The location of antigenic determinants was predicted from the primary and secondary structure of the chains, that is, aromaticity, hydrophilicity and presence of beta-turns. All synthetic peptides reacted with the antiserum to type IV collagen (anti-Col IV). Whereas all peptides arising from the NC-1 domain reacted with anti-NC-1, intact 7-S or peptides of the alpha 1 or alpha 2 chain of the 7-S domain did not react. However intact 7-S reacted with anti-Col IV. Two synthetic peptides from the NC-1 domain of alpha 1, (a.a. 71-90 and a.a. 176-190), one from the alpha 2 (a.a. 70-83) and four from the alpha 3 chain (a.a. 72-89, a.a. 104-117, a.a. 133-145, a.a. 185-203) reacted with anti-NC-1 and anti-COL IV. The above peptides, except alpha 3 (72-89) and alpha 3 (185-203), were tested and found to be reactive with sera from patients with GP.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

PubMed1993

Adhesion promoting property of laminin from normal tissue and from a tumorigenic cell line.

The cell adhesion promoting activity of laminin isolated from normal human placenta was compared with that isolated from mouse EHS tumor and from the cultures of a mouse epithelial cell line B82 and its tumorigenic derivative, B82HT. The adhesion promoting properties of commercial merosin isolated from placenta was also compared with the above preparations using the human fibrosarcoma HT1080 cells. Percent attachment was defined as (radioactivity extracted from attached cells)/(radioactivity in cells added to assay) x 100. HT1080 cells adhered more efficiently on laminin (0.5 micrograms/well), isolated from the B82 rather than B82HT cell conditioned medium, (82% vs 64%). Percent attachment of HT1080 cells on isolated native placental laminin or commercial merosin was significantly higher compared to laminin from the EHS tumor (at 0.75 micrograms/well, 69%, 73% and 20% respectively). In parallel experiments the steady-state levels of mRNAs for subunits A, M, B1 and B2 in cultures of B82 and B82HT cells were determined. The ratio of mRNA for the laminin subunits in B82 and B82HT cells was 1:0.9 for the A chain, 1:0.6 for the M chain, 1:0.4 for the B1 chain, and 1:0.3 for the B2 chain. Protein studies indicated that the M subunit is absent in laminin preparations from the EHS tumor whereas it is abundant in the laminin from placenta and in commercial merosin. Laminin isolated from B82 cells contains a higher proportion of the M subunit compared to that from B82HT cells. The data suggest that there are functional differences between the laminin found in normal tissue and that present in a solid tumor. Functional differences were noted between the laminins synthesized by the B82 cell line and its tumorigenic counterpart, B82HT. These differences may result from the lack of gene expression for the laminin subunit M by the EHS tumor and by the lower degree of gene expression for this subunit by B82HT cells. The possibility that the laminin synthesized by the tumorigenic cell line may be structurally different from that synthesized by the B82 cells should also be considered.

Animals↗

PubMed1991

The effects of interleukin-1 on the expression of thrombospondin and fibronectin by rabbit articular chondrocytes.

Studies to evaluate the effects of recombinant interleukin-1 beta (IL-1) on the expression of matrix proteins by rabbit articular chondrocytes were conducted. Chondrocytes expressed high levels of message for thrombospondin (Tsp) and fibronectin (Fn). RNA slot-blot analysis demonstrated that treatment of the cultures with IL-1 (100 ng/ml) for 24 h caused a 70% suppression of their steady-state Tsp mRNA levels whereas those of Fn were not affected. Steady-state mRNA levels for the intracellular protein, actin, were not modulated by treatment with IL-1. The suppression of Tsp mRNA levels by IL-1 (100 ng/ml) was maximal by 4 h and was concentration dependent; half-maximal suppression was estimated to require 0.12 ng/ml IL-1. Cycloheximide treatment enhanced Tsp mRNA levels, but did not modulate IL-1 suppression of Tsp mRNA. Using pulse-labeling and immunoprecipitation techniques, we found that IL-1 suppression of Tsp mRNA levels was reflected in a coordinate inhibition of Tsp protein synthesis. Chondrocyte synthesis of Fn was not affected by IL-1. These data suggest that IL-1 specifically regulates chondrocyte expression of Tsp at least in part by decreasing the amount of Tsp mRNA available for translation.

Actins↗

PubMed1991

The biosynthesis of proteoglycans and interstitial collagens by bovine pericardial fibroblasts.

The biosynthesis of interstitial collagens (types I and III) and proteoglycans was studied in fibroblasts isolated from the parietal layer of bovine pericardium. Confluent cultures were labeled with Na2 35SO4 for proteoglycans or 14C-proline for collagens. The proteoglycans synthesized by pericardial fibroblasts were purified by DEAE-Sephacel chromatography and further fractionated into three components by gelfilitration. Two minor high molecular weight proteoglycans were shown by SDS-PAGE to be resistant to chondroitinase ABC and AC, and partially degraded by nitrous acid. The major, low molecular weight proteoglycan had a core protein of 45 kDa and is considered to be a dermatan sulfate/chondroitin sulfate proteoglycan since it was resistant to nitrous acid, but digested partially by chondroitinase AC and completely by ABC. The pericardial fibroblasts synthesized predominantly type I collagen and low amounts (about 10%) of type III collagen which was detected by delayed reduction on SDS-PAGE. The data show that pericardial fibroblasts synthesize the same macromolecules that can be extracted from the intact tissue and suggest that the proteoglycan may play a structural as well as physiological role.

Animals↗

PubMed1991

Differential suppression of host cell protein synthesis and mRNA levels in herpes simplex virus-infected endothelial cells.

Earlier studies from this laboratory have shown that infection of vascular cells with herpes simplex virus 1 or 2 (HSV-1, HSV-2) results in the differential suppression of extracellular matrix proteins including fibronectin (FN), type IV collagen, thrombospondin (TSP) and Factor VIII von Willebrand protein. The present study was designed to determine whether a correlation exists between suppression of synthesis of specific proteins and their mRNA levels. We have measured the steady-state levels of mRNAs for several extracellular matrix proteins (type IV collagen, FN and TSP) and two intracellular proteins (actin and tubulin) in human endothelial cells (EC) following HSV-1 infection. The results show that during the first 5 h post-infection, when there is a rapid decrease in the synthesis of extracellular matrix proteins, the steady-state levels of the corresponding mRNAs remain relatively high, but progressively decline to levels of less than 20% by 13 h post-infection. These findings suggest that in the early hours post-infection there is an alteration in the translatability of the hybridizable message followed by degradation in the later hours.

Cells, Cultured↗

PubMed1991

Studies on human laminin and laminin-collagen complexes.

Intact human laminin and laminin type IV collagen complexes were extracted from term placental membranes and their structures were examined by electroimmunoblot and by rotary shadowing electron microscopy. Rotary shadowing electron microscopy revealed a structure of human laminin which is essentially similar to the cruciform structure of the mouse tumor (EHS) laminin, but with some notable differences. The observed lengths of the short arms in the human laminin are different. One short arm has an average length of 34 nm and another short arm a length of 42 nm. In the mouse laminin all three short arms are of equal length. The average length of the long arm is 97 nm, which is longer than that of mouse tumor laminin (77 nm). The distal portion of the long arm has two clearly separated globular domains instead of the single one observed with tumor laminin. Human laminin was found in various states of aggregation including dimers, trimers and higher aggregates. Laminin molecules appeared to attach to a point in type IV collagen located 87 nm from C-terminus, or at 174 nm from C-terminus and one with less frequency, at 251 nm from C-terminus. A small number of molecules appeared to bind at the N-terminus of the collagen. These laminin-collagen interactions occurred via the distal globular domains of both the short and long arms of laminin. The data suggest that human laminin extracted from placenta is structurally different from that isolated from the mouse EHS tumor.

Chromatography, Gel↗

PubMed1991

Changes in the subunit composition of laminin during the increased tumorigenesis of mouse A9 cells.

We compared the structure and subunit composition of laminin in less tumorigenic mouse A9 and highly tumorigenic mouse A9HT cells by pulse-chase studies. During a 15' pulse, the ratio of laminin B1 to B2 subunits in cell lysates is 1:1 in both the A9 and A9HT cells; however, after a 3 hr chase, this ratio changes to 6:1 and 2:1 in the A9 and A9HT cells, respectively. Analysis of mature laminin subunits in culture media after a 3 hr chase also showed a similar higher ratio of B1 to B2 in the A9 cells as compared to the A9HT cells. The higher ratio of B1 to B2 subunits in A9 cells was evident as early as after a 30' pulse. A comparative analysis of steady-state levels of mRNAs for the laminin subunits B1 and B2 between A9 and A9HT cells showed a ratio of 1:1 for B1 and a ratio of 1:1.65 for B2. The ratio of B1 to B2 mRNAs in A9 cells was 1:1.3 whereas in A9HT cells it was 1:2.5, suggesting changes in the processing of mRNA in the highly tumorigenic A9HT cells. These observations suggest that the processing of laminin B subunits is altered during the process of increased tumorigenicity, thus resulting in the synthesis and secretion of structurally different laminin in tumorigenic A9HT cells as compared to the parent and less tumorigenic A9 cells.

Animals↗

PubMed1990

Laminin "A" chain fragment of Mr 43 kilodalton contains PC12 cell attachment promoting site.

In the present study, the ability of a 43 K fragment, originating from the long arm of the 400 K laminin "A" chain (Rao and Kefalides, manuscript in press), to promote the attachment and de novo neurite outgrowth by the pheochromocytoma cell line, (PC12) was studied. Unprimed PC12 cells (not treated with nerve growth factor, NGF), just as the primed cells (treated with NGF), rapidly and efficiently attach to the laminin fragment but less efficiently to the intact laminin coated bacteriological plastic surfaces. The neurite outgrowth was continuous from primed cells attached to both laminin and laminin fragment substrates, when cultured for four days in the presence of NGF. On the other hand, no significant neurite outgrowth was observed from unprimed PC12 cells attached to the laminin fragment coated bacteriological dishes, in the absence of NGF. These data suggest that the 43 K laminin "A" chain fragment contains the PC12 cell attachment promoting site.

Adrenal Gland Neoplasms↗

PubMed1990

Identification and characterization of a 43-kilodalton laminin fragment from the "A" chain (long arm) with high-affinity heparin binding and mammary epithelial cell adhesion-spreading activities.

A recently described procedure of reduction and carboxymethylation followed by heparin-Sepharose chromatography [Arumugham et al. (1988) Connect. Tissue Res. 18, 135-147] was used to characterize high-affinity heparin binding fragments of the laminin "A" chain. Two laminin fragments of Mr 53K and 43K selectively bound to the heparin-Sepharose column from the chymotrypsin digest of laminin, indicating that these fragments originate from the "A" chain. Without reduction and carboxymethylation but in the presence of 2.0 M urea, the heparin-Sepharose-bound material from the chymotrypsin laminin digest contains all the attachment-promoting activity for normal mouse mammary epithelial cells. The reduced 200-kDa intact three short arm fragment, fragments of Mr 70K-160K obtained either from laminin or from the reduced 200-kDa three short arm fragment, and the 53-kDa heparin binding fragment were all inactive in promoting the adhesion of mouse mammary epithelial cells. The mammary epithelial cell adhesion and spreading properties of laminin are associated with the high-affinity heparin binding 43-kDa fragment. The mammary epithelial cells attach to the 43-kDa fragment substrate and synthesize laminin, collagen type IV, and desmoplankins I and II as are the cells attached to laminin substrate and to the cells grown on tissue culture dishes. The biologically active 43-kDa fragment is generated from laminin, but not from the three short arm fragment. These results suggest that normal mouse mammary epithelial cells interact with laminin through a single site which is present in the 43-kDa heparin binding fragment located on the long arm of the "A" chain.

Animals↗

PubMed1990

The effect of heparin on fibronectin and thrombospondin synthesis and mRNA levels in cultured human endothelial cells.

Studies to eludicate the effect of heparin on the synthesis of extracellular matrix components by cultured human umbilical vein endothelial cells (EC) were conducted. Using pulse-labeling and ELISA techniques, we found that EC grown in the presence of heparin (90 micrograms/ml) and endothelial cell growth factor (ECGF) synthesized 50% less fibronectin (FN) than did ECGF-treated control cultures. No change in the synthesis of thrombospondin (TSP) was induced by heparin. The effect of heparin on EC FN synthesis was independent of whether the cells were cultivated on plastic or gelatin substrates. However, ECGF modulates the effect of heparin on EC synthesis of FN. RNA slot-blot analysis demonstrated that heparin treatment specifically decreased the steady-state mRNA levels for both FN and TSP in the cells. Steady-state levels of mRNA for two intracellular proteins, actin and tubulin, were unchanged. These data suggest that heparin decreases EC expression of FN at least in part by decreasing the amount of FN mRNA available for translation. The failure of heparin to inhibit TSP expression, although it reduces TSP mRNA levels, points to the possibility that the rate of EC synthesis of TSP is translationally or post-translationally regulated.

Cells, Cultured↗

PubMed1990

Inhibition of proteoglycan synthesis in human endothelial cells after infection with herpes simplex virus type 1 in vitro.

The effects of herpes simplex virus type 1 (HSV-1) infection on proteoglycan synthesis by human endothelial cells were studied as a model of endothelial cell injury. Confluent cultures of early passage endothelial cells from human umbilical vein were infected with HSV-1 at multiplicities of infection from 0.001 to 1.0. HSV-1 infection produced a dose-dependent inhibition of total proteoglycan synthesis of up to 85%. Although there was a 2- to 3-fold increase in the quantity of virus necessary to cause 50% inhibition of heparan sulfate compared to chondroitin/dermatan sulfate proteoglycan, the inhibition was relatively parallel, even up to high virus doses. There was no inhibition of an undersulfated heparan sulfate proteoglycan that contained glycosaminoglycan chains shorter than the predominant species. The results indicate that HSV-1 infection of human endothelial cells produces complex effects on host-cell metabolism. The viral-induced changes in proteoglycan metabolism may influence cell-matrix interactions and lead to altered vessel wall function.

Cell Membrane↗

PubMed1990

Suppression of host mRNA in human smooth muscle cells by a virion competent factor in herpes simplex virus type 1.

Herpes simplex virus type 1 produces an early decrease in protein synthesis in cultured smooth muscle cells isolated from human umbilical artery. To confirm that suppression of host protein synthesis occurs before virus protein expression, cultures were treated with actinomycin D (5 micrograms/ml) continuously from the beginning of infection. In the presence of actinomycin D, by 3.5 hours postinfection, virus-infected cultures showed much less incorporation of [35S]methionine into sodium dodecyl sulfate-polyacrylamide electrophoresis-separated products than did identically treated mock-infected cultures. In the absence of actinomycin D, there was incorporation of radiolabel into viral proteins as early as 4.5 hours postinfection. Hybridization of slot-blotted total RNA demonstrated that virus-infected cultures treated with and without actinomycin D showed a marked decrease in hybridizable RNA by 2 hours PI when compared with mock-infected controls. This decrease was seen with cDNA probes for the mRNA for secreted extracellular matrix macromolecules (fibronectin, thrombospondin and collagen chains alpha 2(I), alpha 1(III] as well as with cDNA probes for RNA of intracellular macromolecules actin and beta-tubulin. In vitro translation of total RNA isolated from infected human smooth muscle cells at 2 and 5 hours postinfection resulted in far less [35S]methionine incorporation into sodium dodecyl sulfate-polyacrylamide electrophoresis-separated products than would be predicted from the amount of hybridizable RNA available. The results suggest that host message is rapidly rendered nonfunctional as well as degraded by means of a virion-competent mechanism(s).

Dactinomycin↗

PubMed1989

Heparin increases mRNA levels of thrombospondin but not fibronectin in human vascular smooth muscle cells.

The effects of heparin (180 micrograms/ml) on steady state mRNA levels for fibronectin, thrombospondin, actin and collagen types I and III were investigated in human umbilical artery smooth muscle cells. Heparin caused a 120% increase in thrombospondin mRNA levels and a 60% and 180% increase in the mRNA levels of procollagen chains alpha 2(I) and alpha 1(III), respectively. No change in fibronectin or actin mRNA levels resulted from heparin treatment. We reported earlier (Biochem. Biophys. Res. Comm. 148:1264, 1987) that heparin increases smooth muscle cell synthesis of both fibronectin and thrombospondin. These data show that heparin coordinately regulates thrombospondin mRNA and protein levels. The heparin induced increase in fibronectin biosynthesis apparently reflects control at the translational or post-translational level.

Actins↗