Enhanced cellular fibronectin accumulation in chondrocytes treated with vitamin A.

Chick sternal chondrocytes cultured at high cell density lack fibronectin as a surface protein, while vitamin A-treated chondrocytes contain it as the major cell surface protein. We investigated the mechanism of fibronectin accumulation under these conditions. Control chondrocytes synthesized nearly as much fibronectin as vitamin A-treated chondrocytes, but it was secreted primarily into culture medium. Althought the fibronectin of control chondrocytes was of a slightly lower apparent molecular weight than the fibronectin synthesized by the treated cells, it bound as effectively to the cell layer of both normal and treated cells. In contrast, the vitamin A-treated cultures were 2.7 fold more effective in binding fibronectin synthesized by either control or treated cells. Thus in chondrocytes, vitamin A appears to regulate the cellular accumulation of fibronectin by increasing the ability of the cell layer to bind fibronectin rather than by altering its synthesis or its adhesivity for the cell layer.     

Response to osmotic stress and temperature of the fungus <Emphasis Type="Italic">Ustilago maydis</Emphasis>

Ustilago maydis is a fungal pathogen which is exposed during its life cycle to both abiotic and biotic stresses before and after the infection of maize. To cope with extreme environmental changes, microorganisms usually accumulate the disaccharide trehalose. We have investigated both the accumulation of trehalose and the activity of trehalase during the adaptation of U. maydis haploid cells to thermal, sorbitol, and NaCl stresses. Sorbitol and sodium chloride induced sustained accumulation of trehalose, while a transient increase was observed under heat stress. Sorbitol stressed cells showed higher trehalase activity compared with control cells and to those stressed by NaCl and high temperature. Addition of cycloheximide, a protein synthesis inhibitor, did not affect the trehalose accumulation during the first 15 min, but basal levels of trehalose were reached after the second period of 15 min. The proteomic analysis of the response of U. maydis to temperature, sorbitol, and salt stresses indicated a complex pattern which highlights the change of 18 proteins involved in carbohydrate and amino acid metabolism, protein folding, redox regulation, ion homeostasis, and stress response. We hypothesize that trehalose accumulation during sorbitol stress in U. maydis might be related to the adaptation of this organism during plant infection.     

Beta-type transforming growth factor specifies organizational behavior in vascular smooth muscle cell cultures

In culture, vascular smooth muscle cells (SMC) grow in a "hill-and-valley" (multilayered) pattern of organization. We have studied the growth, behavioral organization, and biosynthetic phenotype of rat aortic SMC exposed to purified platelet-derived growth regulatory molecules. We show that multilayered growth is not a constitutive feature of cultured SMC, and that beta-type transforming growth factor (TGF-beta) is the primary determinant of multilayered growth and the hill-and-valley pattern of organization diagnostic for SMC in culture. TGF-beta inhibited, in a dose-dependent manner, the serum- or platelet-derived growth factor-mediated proliferation of these cells in two-dimensional culture, but only when cells were plated at subconfluent densities. The ability of TGF-beta to inhibit SMC growth was inversely correlated to plating cell density. When SMC were plated at monolayer density (5 X 10(4) cells/cm2) to allow maximal cell-to-cell contact, TGF-beta potentiated cell growth. This differential response of SMC to TGF-beta may contribute to the hill-and-valley pattern of organization. Unlike its effect on other cell types, TGF-beta did not enhance the synthesis of fibronectin or its incorporation into the extracellular matrix. However, the synthesis of a number of other secreted proteins was altered by TGF-beta treatment. SMC treated with TGF-beta for 4 or 8 h secreted markedly enhanced amounts of an Mr 38,000-D protein doublet whose synthesis is known to be increased by heparin (another inhibitor of SMC growth), suggesting metabolic similarities between heparin- and TGF-beta-mediated SMC growth inhibition. The data suggest that TGF-beta may play an important and complex regulatory role in SMC proliferation and organization during development and after vascular injury.     

Adhesion-induced intracellular signalling in endothelial cells depends on the nature of the matrix

The adhesion of a human microvascular endothelial cell line to its own matrix was studied in comparison with adhesion of the same cells to fibronectin or thrombospondin-1. These endothelial cells adhered preferentially to their matrix whereas an equal cell number was attached to fibronectin or thrombospondin-1. The adhesion of cells to thrombospondin-1 was mediated by the N-terminal heparin binding domain of thrombospondin-1 as shown by the use of a recombinant fragment, N18. Cells adhering to their matrix displayed a morphology and a cytoskeleton organization very similar to that observed in vivo with an apical immunostaining for actin stress fibers and a fine basal labeling for vinculin. Cells on fibronectin were extensively spread and rapidly assembled stress fibers and focal contacts. Cells adherent to thrombospondin-1 presented large lamellae rich in actin but devoid of vinculin and only few actin fibers were observed. Depending on the substratum used, adhering endothelial cells displayed also different tyrosine phosphorylation patterns on electrophoresis. Our observations indicate that endothelial cells adhering to their matrix present an activation state intermediate between that induced by a "hyperadhesive" protein like fibronectin and that generated by a moderate, indeed anti-adhesive, protein like thrombospondin-1.     

Fibronectin stimulates growth but not follicle-stimulating hormone-dependent differentiation of rat granulosa cells in vitro

Since fibronectin is a secretory product of immature rat granulosa cells in culture and may contribute to the follicular microenvironment in vivo, we have studied the effects of this adhesion factor on follicle-stimulating hormone (FSH)-dependent differentiation in short-term (2-3-day) cultures and on growth and protein synthesis in long-term (12-day) cultures. In comparison with cells plated on tissue culture plastic, those plated on an optimal fibronectin-coated substratum showed much greater cell spreading. There were no short-term effects of this morphological change on FSH-stimulation of cyclic AMP production, apparent activities of aromatase or cholesterol side-chain cleavage enzymes, or acquisition of luteinizing hormone (LH) responsiveness in cultured cells. However, progesterone metabolism to 20 alpha-hydroxypregnan-4-en-3-one was increased. Only cultures on fibronectin showed increases between days 3 and 9 in protein (2.5-fold) and DNA (1.4-fold) contents. Cells cultured on fibronectin also showed greater uptake and incorporation of [3H]leucine in comparison with cells cultured on plastic. FSH treatment caused cell aggregation and rounding and delayed the increase in protein content of cells cultured on fibronectin. The results presented demonstrate that the principal direct effect of fibronectin-mediated adhesion on rat granulosa cells is to enhance cell maintenance and growth, while having no generalized action on FSH-dependent differentiation.     

Induction of stress proteins in the phototrophic bacterium Rhodobacter sphaeroides

The stress response of the phototrophic bacterium Rhodobacter sphaeroides was investigated by two-dimensional gel electrophoresis. Oxygen, 0.5% and 4% ethanol, UV radiation, heat shock at 42°C and 0.01% phenanthrene were tested as stress factors. The protein pattern on two-dimensional gels of stressed as compared to control cells revealed that all stress factors applied caused modifications in the protein pattern of R. sphaeroides. The intensity of particular spots increased or decreased as a consequence of altered protein synthesis. Specific and general stress responses were observed.     

Osmotically Induced Proline Accumulation in <Emphasis Type="Italic">Lotus Corniculatus</Emphasis> Leaves is Affected by Light and Nitrogen Source

Proline accumulation in osmotically stressed leaves of Lotus corniculatus was stimulated by increasing light intensity (photon fluence density, PFD). Treatment with propanil limited proline accumulation in response to light and osmotic stress, indicating a dependence of proline synthesis on photosynthetic NADPH. Drought stress induced proline accumulation in L. corniculatus both in nitrate-fed plant (NFP) and ammonium-fed plants (AFP), although higher proline concentration was observed in AFP than in NFP after 24 h of drought stress. Changes in proline accumulation induced by drought stress in plants grown under different nitrogen regimes could not be explained by changes of either total protein or amino acids, consistent with specifically altered regulation of proline synthesis. Under control conditions, alanine, aspartate and glutamate were the predominant amino acids in NFP; conversely, in AFP, arginine and ornithine were the predominant amino acids. Only the NFP regime showed changes in the concentrations of specific amino acids under drought stress a decrease in alanine, aspartate and glutamate and increased gama-aminobutyric acid. In AFP and especially NFP, proline accumulation under osmotic stress was associated with increased ornithine amino transferase activity. An increase of both activity and protein of ferredoxin-dependent glutamate synthase was observed in osmotic-stressed NFP; inversely both decreased in drought-stressed AFP. PFD and nitrogen source are therefore shown to be regulators of proline accumulation in L. corniculatus osmotically stressed plants.     

Adhesion Complexes Formed by OVCAR-4 Cells on Laminin 1 Differ from Those Observed on Fibronectin

Cell adhesion to laminin 1 or to fibronectin is mediated by distinct sets of integrins and is differentially regulated by protein kinase C (PKC). It suggests that upon integrin ligation to laminin 1 or to fibronectin different intracellular signaling pathways could be activated. We have therefore investigated the formation of signaling complexes induced during cell adhesion to laminin 1 or to fibronectin. Following cell adhesion to laminin 1 the re-arrangement of the cytoskeleton was slower than that observed on fibronectin and it was activated by treating the cells with H-7, an inhibitor of PKC. Conversely, treatment of laminin-adhering cells with a PKC activator resulted in a rapid disorganization of the actin cytoskeleton while a similar treatment had no effect on fibronectin-adhering cells. These results suggested that the structural organization of the adhesion complexes might be substrate-specific and might correspond to a different arrangement of cytoskeletal and/or cytoplasmic proteins. Reflection interference contrast microscopy (RICM) images revealed that cell-substratum contacts formed on laminin 1 were not well differentiated in contrast to those developed on fibronectin. However, immunofluorescence staining revealed a similar organisation of actin microfilaments, talin and phosphotyrosyl-containing proteins on both substrates. In contrast, differences were observed for vinculin distribution within cells spread on fibronectin or on laminin I. Following cell adhesion to fibronectin most of the vinculin appeared as thick patches at the tips of the actin stress fibers while in laminin-adhering cells vinculin was recruited into thin streaks localized at the end of only some actin stress fibers.     

Focal adhesion sites and the removal of substratum-bound fibronectin

Fibronectin was not removed from the substratum beneath focal adhesion sites when fibroblasts spread in serum-free medium on adsorbed fibronectin substrata, or when fibroblasts spread in serum-containing medium on covalently cross-linked fibronectin substrata. Under these conditions, there was colocalization between 140-kD fibronectin receptors and focal adhesion sites. It was concluded that removal of adsorbed fibronectin from beneath focal adhesion sites was a mechanical process that required serum. The effect of serum was nonspecific since serum could be replaced by equivalent concentrations of serum albumin, ovalbumin, or gamma globulins. Quantitative measurements indicated that the presence of proteins in the incubation medium weakens the interaction of fibronectin with the substratum, thereby allowing the adsorbed protein to be removed from the substratum at sites of high stress. After removing fibronectin from the substratum, cells reorganized this material into patches and fibrils beneath cells, and the reorganized fibronectin colocalized with fibronectin receptors. Some of the patches of fibronectin were phagocytosed. The fibronectin fibrils were observed to be in register with actin filament bundles and sometimes translocated to the upper cell surfaces. It is proposed that removal of fibronectin from beneath focal adhesion sites is an example of how cells can modify their extracellular matrices through contractile activity.     

Accumulation of glutamate by Salmonella typhimurium in response to osmotic stress.

Salmonella typhimurium accumulates glutamate in response to osmotic stress. Cells in aerobic exponential growth have an intracellular pool of approximately 125 nmol of glutamate mg of protein-1. When cells were grown in minimal medium with 500 mM NaCl, KCl, or sucrose, 290 to 430 nmol of glutamate was found to accumulate. Values were lower when cells were harvested in stationary phase. Cells were grown in conventional medium, harvested, washed, resuspended in the control medium or in medium with osmolytes, and aerated for 1 h. With aeration, glutamate was found to accumulate at levels comparable to those observed in exponential cultures. Antibiotics inhibiting protein synthesis did not affect glutamate accumulation when cells were aerated. Strains with mutations in glutamate synthase (glt) or in glutamate dehydrogenase (gdh) accumulated nearly normal levels of glutamate under these conditions. A double (gdh glt) mutant accumulated much less glutamate (63.9 nmol mg of protein-1), but a 1.9-fold excess accumulated when cells were aerated with osmotic stress. Methionine sulfone, an inhibitor of glutamate synthase, did not prevent accumulation of glutamate in cells aerated with osmotic stress. Glutamate dehydrogenase is thought to have minimum activity when ammonium is limiting. Resuspending cells with limiting ammonium reduced glutamate production but did not eliminate accumulation of excess glutamate when cells were osmotically stressed. Amino oxyacetic acid, an inhibitor of transamination reactions, did not prevent accumulation of excess glutamate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Extracellular myocilin affects activity of human trabecular meshwork cells

The trabecular meshwork (TM), a specialized eye tissue, is a major site for regulation of the aqueous humor outflow. Malfunctioning of this tissue is believed to be responsible for development of glaucoma, a blinding disease. Myocilin is a gene linked to the most common form of glaucoma. The protein product has been localized to both intra and extracellular sites, but its function still remains unclear. This study was to determine whether extracellular myocilin presented in the matrix affects adhesion, morphology, and migratory and phagocytic activities of human TM cells in culture. Cell adhesion assays indicated that TM cells, while adhering readily on fibronectin, failed to attach on recombinant myocilin purified from bacterial cultures. Adhesion on fibronectin was also compromised by myocilin in a dose dependent manner. Myocilin in addition triggered TM cells to assume a stellate appearance with broad cell bodies and microspikes. Loss of actin stress fibers and focal adhesions was observed. TM cell migration on fibronectin/myocilin to scratched wounds was reduced compared to fibronectin controls. Myocilin, however, had little impact on phagocytic activities of TM cells. Cell attachment on fibronectin and migration of corneal fibroblasts, a control cell type, were not altered by myocilin. These results demonstrate that extracellular myocilin elicits anti-adhesive and counter-migratory effects on TM cells. Myocilin in the matrix of tissues could be exerting a similar influence on TM cells in vivo, impacting the flexibility and resilience required for maintenance of the normal aqueous outflow.     

Cellular and metabolic specificity in the interaction of adhesion proteins with collagen and with cells

Fibronectin mediates the adhesion of fibroblasts to collagen substrates, binding first to the collagen and then to the cells. We report here that the interaction of the cells with the fibronectin-collagen complex is blocked by specific gangliosides, GD_{1 a} and GT₁, and that the sugar moieties of these gangliosides contain the inhibitory activity. The gangliosides act by binding to fibronectin, suggesting that they may be the cell surface receptor for fibronectin. Evidence is presented that other adhesion proteins or mechanisms of attachment exist for chondrocytes, epidermal cells, and transformed tumorigenic cells, since adhesion of these cells is not stimulated by fibronectin. Chondrocytes adhere via a serum factor that is more temperature-sensitive and less basic than fibronectin. Unlike that of fibroblasts chondrocyte adhesion is stimulated by low levels of gangliosides. Epidermal cells adhere preferentially to type IV (basement membrane) collagen but at a much slower rate than fibroblasts or chondrocytes. This suggests that these epidermal cells synthesize their own specific adhesion factor. Metastatic cells cultured from the T241 fibrosarcoma adhere rapidly to type IV collagen in the absence of fibronectin and do not synthesize significant amounts of collagen or fibronectin. Their growth, in contrast to that of normal fibroblasts, is unaffected by a specific inhibitor of collagen synthesis. These data indicate the importance of specific collagens and adhesion proteins in the adhesion of certain cells and suggest that a reduction in the synthesis of collagen and of fibronectin is related to some of the abnormalities observed in transformed cells.     

Modulation of cultured chicken growth plate chondrocytes by transforming growth factor-beta 1 and basic fibroblast growth factor.

Expression of several cellular and matrix proteins which increase significantly during the maturation of growth plate cartilage has been shown to be affected by various endocrine and autocrine factors. In the studies reported here, transforming growth factor-beta (TGF-beta 1) and basic fibroblast growth factor (bFGF) were administered to primary cultures of avian growth plate chondrocytes at pre- or post-confluent stages to study the interplay that occurs between these factors in modulating chondrocytic phenotype. Added continuously to pre-confluent chondrocytes, TGF-beta 1 stimulated the cells to produce abundant extracellular matrix and multilayered cell growth; cell morphology was altered to a more spherical configuration. These effects were generally mimicked by bFGF, but cell shape was not affected. Administered together with TGF-beta 1, bFGF caused additive stimulation of protein synthesis, and alkaline phosphatase (AP) activity was markedly, but transiently enhanced. During this pre-confluent stage, TGF-beta 1 also increased fibronectin secretion into the culture medium. Added to post-confluent cells, TGF-beta 1 alone caused a dosage-dependent suppression of AP activity, but bFGF alone did not. Under these conditions, TGF-beta 1 and bFGF had little effect on general protein synthesis, but TGF-beta 1 alone caused large, dosage-dependent increases in synthesis of fibronectin, and to some extent type II and X collagens. Given together with bFGF, TGF-beta 1 synergistically increased secretion of fibronectin. These findings reveal that regulation of phenotypic expression in maturing growth plate chondrocytes involves complex interactions between growth factors that are determined by timing, level, continuity, and length of exposure.     

镉胁迫对丹参生长及有效成分积累的影响研究

采用盆栽试验方法,研究了镉（Cd2＋）对丹参（Salvia miltiorrhiza Bunge）的生长及其有效成分积累的影响。结果表明,镉胁迫下丹参的生长受到了显著抑制,体内Cd2＋残留量、可溶性蛋白含量和膜脂过氧化程度显著增加,叶绿素含量降低。与对照相比,镉胁迫下丹参叶片水溶性酚酸类化合物咖啡酸和迷迭香酸的含量显著降低（P〈0．05）,原儿茶酸含量增加,丹参素、原儿茶醛和丹酚酸B的含量也降低,但变化均不显著（P〉0．05）。而根系中这6种酚酸类化合物含量均降低,其中迷迭香酸的含量变化极显著（P〈0．01）。镉胁迫下丹参根系脂溶性丹参酮类化合物二氢丹参酮、丹参酮I和隐丹参酮含量均显著降低,而丹参酮lIA含量变化不显著。丹参叶片中水溶性酚酸类化合物合成关键酶苯丙氨酸解氨酶（PAL）和酪氨酸氨基转移酶（TAT）的活性显著降低,而肉桂酸4一羟化酶（C4H）和4一香豆酸CoA连接酶（4CL）的活性显著升高。这些结果均说明镉胁迫可以降低丹参的产量和质量。     

Platelet-derived growth factor inhibits smooth muscle cell adhesion to fibronectin by ERK-dependent and ERK-independent pathways

The adhesion of cells to the extracellular matrix plays a major role in cell migration. Pretreatment with platelet-derived growth factor (PDGF) inhibited the adhesion of smooth muscle cells to fibronectin by 80%. This inhibition decreased as concentrations of fibronectin increased. In the presence of 200 microm GRGDS peptide, only 45% of PDGF-treated cells adhered to fibronectin compared with 80% of control cells. This indicates that a decrease in integrin avidity was induced by PDGF. Cell adhesion was partially restored when the activation of the extracellular signal-regulated kinase (ERK) was inhibited with PD98059. The remaining inhibition of adhesion (50%) was independent of the fibronectin concentration, suggesting that the ERK pathway is involved in the decrease in integrin avidity. This was confirmed by depleting ERK protein levels by treatment with ERK antisense oligonucleotide. The adhesion of ERK control oligonucleotide-treated cells decreased by 41% when the concentration of GRGDS peptide was increased from 50 to 200 microm but only decreased by 11% in ERK antisense oligonucleotide-treated cells. Treatment with PDGF also delayed focal complex assembly and inhibited stress fiber formation. Consistent with a delay in tyrosine phosphorylation of paxillin, PDGF treatment caused a lag in focal complex formation, although this was not associated with any change in Src family tyrosine kinase activity. Our results indicate that PDGF inhibits smooth muscle cells adhesion by two pathways. The first involves an ERK-dependent decrease in integrin avidity; the second involves the ERK-independent inhibition of focal complex assembly.     

Effects of NaCl and iso-osmotic PEG stress on growth,osmolytes accumulation and antioxidant defense in cultured sugarcane cells

In order to discriminate between the ionic and osmotic components of salt stress, sugarcane (Saccharum officinarum L. cv. Co 86032) calli were cultured on media containing NaCl or polyethylene glycol (PEG) 8000 that exerted the same osmotic pressure (−0.7 MPa). PEG stress exposure for 15 days led to significant growth reduction and loss in water content than salt stressed and control tissues. Osmotic adjustment (OA) was observed in callus tissues grown on salt, but was not evident in callus grown on PEG. Oxidative damage to membranes, estimated in terms of accumulation of thiobarbituric acid reactive substances-TBARS and electrolytic leakage was significantly higher in both the stressed calli than the control however, the extent of damage was more in the PEG stressed calli. The stressed callus tissues showed inhibition of ascorbate peroxidase activity, while catalase activity was increased. These results indicate sensitivity of cells to PEG-mediated stress than salt stress and differences in their OA to these two stress conditions. The sensitivity to the osmotic stress indicate that expression of the stress tolerance response requires the coordinated action of different tissues in a plant and hence was not expressed at the cellular level.     

Analysis of proteins synthesized by Salmonella typhimurium during growth within a host macrophage.

Salmonella typhimurium is a facultative intracellular pathogen, able both to invade and to survive within eukaryotic cells and to grow in various extracellular environments. To compare the bacterial responses to these disparate environments and to shed light on the nature of the intracellular environment, we have examined the pattern of protein synthesis by two-dimensional polyacrylamide gel electrophoresis. The levels of approximately 40 proteins were observed to increase during growth within macrophage-like U937 cells, while approximately 100 proteins exhibited levels that were repressed relative to those of an extracellular control culture. To aid in the interpretation of these results, the patterns of proteins made by S. typhimurium exposed to various environmental conditions in the laboratory were determined. The intracellular protein pattern was then compared with each of these benchmark protein patterns. This analysis revealed that, as expected, the intracellular environment appears to impose numerous stresses on the bacteria, but unexpectedly, the macrophage-induced response was not a simple sum of the individual stress responses displayed during extracellular growth.     

Impact of oxidative stress on the function,abundance, and turnover of the Arabidopsis 80S cytosolic ribosome

Abiotic stress in plants causes accumulation of reactive oxygen species (ROS) leading to the need for new protein synthesis to defend against ROS and to replace existing proteins that are damaged by oxidation. Functional plant ribosomes are critical for these activities, however we know little about the impact of oxidative stress on plant ribosome abundance, turnover, and function. Using Arabidopsis cell culture as a model system, we induced oxidative stress using 1 µm of H₂O₂ or 5 µm menadione to more than halve cell growth rate and limit total protein content. We show that ribosome content on a total cell protein basis decreased in oxidatively stressed cells. However, overall protein synthesis rates on a ribosome abundance basis showed the resident ribosomes retained their function in oxidatively stressed cells. ¹⁵N progressive labelling was used to calculate the rate of ribosome synthesis and degradation to track the fate of 62 r‐proteins. The degradation rates and the synthesis rates of most r‐proteins slowed following oxidative stress leading to an ageing population of ribosomes in stressed cells. However, there were exceptions to this trend; r‐protein RPS14C doubled its degradation rate in both oxidative treatments. Overall, we show that ribosome abundance decreases and their age increases with oxidative stress in line with loss of cell growth rate and total cellular protein amount, but ribosome function of the ageing ribosomes appeared to be maintained concomittently with differences in the turnover rate and abundance of specific ribosomal proteins. Data are available via ProteomeXchange with identifier PXD012840.     

Adhesion and cytoskeletal organisation of fibroblasts in response to fibronectin fragments.

Fibronectin has been shown previously to promote complete cell adhesion in the absence of other serum components or de novo protein synthesis. Recently a sequence of four amino acids from the cell-binding domain of fibronectin has been termed the 'cell recognition site' of this multidomain molecule since it mediates cell attachment and inhibits cell adhesion to intact fibronectin. We show here, however, that substrata coated with an isolated cell-binding domain of fibronectin are not sufficient for complete cell adhesion; cells attach and spread but, unlike those adhering to intact fibronectin, they do not form stress fibres terminating in focal adhesions. An additional external stimulus is needed for this cytoskeletal reorganisation and may be provided by one of two heparin-binding fragments of fibronectin. The two 'signals' required for complete adhesion need not be provided simultaneously since focal adhesion formation can be promoted by stimulating cells pre-spread on a cell-binding fragment of fibronectin with a soluble heparin-binding fragment. This second stimulation may involve cell membrane heparan sulphate proteoglycans.     

Integrin-dependent interaction of human vascular endothelial cells on biomimetic peptide surfactant polymers

Biomimetic surfactant polymers designed by molecular grafting of pendant RGD peptides (Pep) and dextran oligosaccharides (Dex) in different ratios onto the backbone of poly(vinyl amine) (PVAm) were examined for their ability to promote endothelial cell (EC) growth. Adhesion, formation of focal contacts, and expression of integrin receptors were examined in EC seeded onto a series of novel surfactants containing 100% dextran (PVAm[Pep (0%)]) to 100% peptide (PVAm[Pep (100%)]) compared to fibronectin control. Interaction of EC on polymer was specific, as soluble GRGDSP, but not GRGESP, was able to inhibit both adhesion and spreading of EC. At three hours, EC attachment and spreading were rapid and comparable on fibronectin and PVAm[Pep (100%)], rounded on PVAm[Pep (0%)], and intermediate on PVAm[Pep (25%)], (PVAm[Pep (50%)], and PVAm[Pep (75%)], with increasing peptide ratio favoring more spreading, although all the substrates had similar hydrophilicity. Cells that spread well on fibronectin and PVAm[Pep (100%)] had sharp spikes of vinculin localized at the termination point of actin stress fibers. Formation of stress fibers and focal adhesions on other substrates were correlated with spreading pattern of EC and the peptide content. EC seeded on fibronectin expressed alpha5beta1 integrins all along the stress fibers and throughout the entire cytoskeleton, but this distribution pattern was less prominent on PVAm[Pep (100%)]. However, expression and distribution of vitronectin receptors (alpha(v)beta3) were similar on both fibronectin and PVAm[Pep (100%)], suggesting a strong cell adhesion on PVAm[Pep (100%)]. Viability of EC was also comparable on both fibronectin and PVAm[Pep (100%)] at 24 h. Substrates with high proportion of dextran limited cell adhesion, probably by decreasing protein adsorption. These results suggest that it may be possible to engineer substrates that promote cell adhesion in a receptor-dependent manner while blocking nonspecific protein adsorption, which may have potential as interface materials for prostheses used in cardiovascular system.