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Biomedical subjects

T J Lawley

Publications and source records attributed to T J Lawley.

At least 19 recordsLinked to original sources
PubMed1992

Regulation of vascular cell adhesion molecule 1 on human dermal microvascular endothelial cells.

Vascular endothelial cell adhesion molecule 1 (VCAM-1) is an adherence molecule that is induced on endothelial cells by cytokine stimulation and can mediate binding of lymphocytes or tumor cells to endothelium. Because these interactions often occur at the level of the microvasculature, we have examined the regulation of expression of VCAM-1 in human dermal microvascular endothelial cells (HDMEC) and compared it to the regulation of VCAM-1 in large vessel human umbilical vein endothelial cells (HUVEC). Both cell populations were judged pure as assessed by expression of von Willebrand factor and uptake of acetylated low density lipoprotein. Expression of VCAM-1 was not detectable on either unstimulated HDMEC or HUVEC when assessed by ELISA or flow cytometry. Stimulation of either HDMEC or HUVEC with TNF-alpha resulted in a time- and dose-dependent induction of VCAM-1. However, although TNF-alpha-induced cell surface and mRNA expression of VCAM-1 in HDMEC was transient, peaking after 16 h of stimulation, TNF stimulation led to persistently elevated cell surface expression of VCAM-1 on HUVEC. IL-1 alpha also induced cell surface expression of VCAM-1 on HUVEC in a time- and dose-dependent manner, but stimulation of HDMEC with IL-1 alpha at doses up to 1000 U/ml failed to induce significant cell surface expression. However, IL-1 alpha induced time- and dose-dependent increases in ICAM-1 on HDMEC. Similarly, IL-4 induced VCAM-1 expression and augmented TNF-alpha-induced expression on HUVEC but did not affect VCAM-1 expression on HDMEC. Binding of Ramos cells to cytokine-stimulated endothelial cell monolayers correlated with VCAM-1 induction. Increased binding was seen after stimulation of HDMEC with TNF-alpha, which was blocked by anti-VCAM-1 mAb, but no increases in binding were noted after stimulation of HDMEC monolayers with IL-1 alpha. These data provide additional evidence for the existence of endothelial cell heterogeneity and differences in cell adhesion molecule regulation on endothelial cells derived from different vascular beds.

Cell Adhesion Molecules↗
PubMed1992

Human dermal microvascular endothelial but not human umbilical vein endothelial cells express CD36 in vivo and in vitro.

CD36 is an 88-kDa glycoprotein that has been identified on platelets, monocytes, and some endothelial cells. Experimental evidence suggests that CD36 mediates the binding of Plasmodium falciparum-infected RBC to a variety of cells, and therefore may play a role in the vascular complications associated with malaria. Additionally, CD36 may also bind the extracellular matrix proteins thrombospondin and collagen. Human umbilical vein endothelial cells have been used in in vitro models examining the binding of P. falciparum RBC to endothelial cells, but they do not consistently express cell surface CD36. Inasmuch as human dermal microvascular endothelial cells (HDMEC) differ in a variety of ways from large vessel endothelial cells, we have examined HDMEC for cell surface expression of CD36 in vivo and in vitro. Direct immunofluorescence of skin showed bright staining of HDMEC with antibody recognizing CD36 and flow cytometric analysis of cultured HDMEC revealed cell surface expression. In contrast, large vessel endothelial cells were not stained with antibody recognizing CD36 in vivo and cultured cells derived from umbilical vein failed to express cell surface CD36 in vitro. Western immunoblots of lysates of HDMEC but not human umbilical vein endothelial cells demonstrated an 88-kDa protein that comigrated with CD36 from platelets. Functional studies demonstrated that adherence of PRBC to HDMEC was inhibited up to 66% by mAb recognizing CD36. Furthermore, the expression of CD36 on HDMEC was increased in a dose- and time-dependent manner by IFN-gamma, and was decreased by protein kinase C agonists. These data demonstrate that HDMEC express functionally active CD36 and this expression can be positively and negatively regulated by soluble factors. This study demonstrates that HDMEC are useful in the study of CD36-mediated binding of PRBC to endothelial cells in vitro and provides further evidence of distinct phenotypic differences between HDMEC and large vessel endothelial cells.

Antigens, CD↗
PubMed1992

VCAM-1-, ELAM-1-, and ICAM-1-independent adhesion of melanoma cells to cultured human dermal microvascular endothelial cells.

We have examined the mechanisms by which tumor cells bind to endothelial cells utilizing cultured melanoma cells and microvascular endothelial cells derived from human dermis (HDMEC). The ability of biologic response modifiers (BRM) to modulate the adhesion of melanoma cells to HDMEC was defined and those results were compared with results from human umbilical vein endothelial cells (HUVEC). SK-MEL-2, WM266-4, and Hs 294T melanoma cells all bound to HDMEC and HUVEC monolayers and adherence of melanoma cells was enhanced in a dose- and time-dependent manner by the treatment of HDMEC with interleukin 1 (IL-1) alpha or tumor necrosis factor (TNF) alpha. Similar increases in binding to HDMEC or HUVEC were induced after BRM stimulation, although baseline melanoma cell binding to HUVEC tended to be slightly higher than to HDMEC. In contrast, whereas phorbol 12-myristate 13-acetate (PMA) augmented melanoma cell adherence to HDMEC, PMA failed to increase adherence to HUVEC. The alterations in melanoma cell binding were induced only after pretreatment of endothelial and not melanoma cells with PMA. Studies of the expression of cell adhesion molecules (CAM) on HDMEC and HUVEC using enzyme-linked immunosorbent assay showed that vascular cell adhesion molecule 1 (VCAM-1) is not induced by PMA on HDMEC and intercellular adhesion molecule 1 (ICAM-1) is downregulated on HDMEC by PMA treatment. Endothelial leukocyte adhesion molecule 1 (ELAM-1) is induced by PMA, IL-1 alpha, or TNFalpha, but its expression does not correlate with increased melanoma cell binding MoAb recognizing VCAM-1-inhibited TNFalpha-induced increases in melanoma cell binding to HUVEC. However, anti-VCAM-1 antibody failed to clock melanoma cell binding to PMA or IL-1 alpha-stimulated HDMEC and only partially inhibited melanoma cell binding to TNF alpha-stimulated HDMEC. This study demonstrates that PMA and IL-1 alpha-induced increases in melanoma cell adherence to HDMEC are not mediated via known CAM, including ICAM-1, VCAM-1, or ELAM-1, and may be affected through microvessel-specific novel proteins not previously described on endothelial cells.

Antibodies, Monoclonal↗
PubMed1992

HMEC-1: establishment of an immortalized human microvascular endothelial cell line.

The study of human microvascular endothelial cells has been limited, because these cells are difficult to isolate in pure culture, are fastidious in their in vitro growth requirements, and have a very limited lifespan. In order to overcome these difficulties, we have transfected human dermal microvascular endothelial cells (HMEC) with a PBR-322-based plasmid containing the coding region for the simian virus 40 A gene product, large T antigen, and succeeded in immortalizing them. These cells, termed CDC/EU.HMEC-1 (HMEC-1), have been passaged 95 times to date and show no signs of senescence, whereas normal microvascular endothelial cells undergo senescence at passages 8-10. HMEC-1 exhibit typical cobblestone morphology when grown in monolayer culture, express and secrete von Willebrand's Factor, take up acteylated low-density lipoprotein, and rapidly form tubes when cultured on matrigel. HMEC-1 grow to densities three to seven times higher than microvascular endothelial cells and require much less stringent growth medium. HMEC-1 will grow in the absence of human serum, whereas microvascular endothelial cells require culture medium supplemented with 30% human serum. These cells express other cell-surface molecules typically associated with endothelial cells, including CD31 and CD36 and epitopes identified by monoclonal antibodies EN4 and PAL-E. They also express the cell adhesion molecules ICAM-1 and CD44 and following stimulation with interferon-gamma express major histocompatibility complex class II antigens. HMEC-1 specifically bind lymphocytes in cell adhesion assays. Thus HMEC-1 is the first immortalized human microvascular endothelial cell line that retains the morphologic, phenotypic, and functional characteristics of normal human microvascular endothelial cells.

Antigens, Differentiation, Myelomonocytic↗
PubMed1992

Expression and modulation of the vitronectin receptor on human dermal microvascular endothelial cells.

Microvascular endothelial cells express a variety of cell-surface integrins in vivo and in vitro with varying affinities for matrix proteins. The vitronectin receptor (VnR), a complex of the alpha v and beta 3 integrin chains, is capable of binding to a variety of matrix proteins that are deposited in injured tissues, including vitronectin, fibrinogen, and thrombin. Staining of frozen sections of human skin with antibodies recognizing the VnR and examination by immunofluorescence microscopy demonstrates staining in a vascular pattern suggesting in vivo expression of the vitronectin receptor on endothelial cells. Examination of pure cultures of human dermal microvascular endothelial cells (HDMEC) by flow-cytometric analysis and enzyme-linked immunosorbent assay confirmed that HDMEC also express cell surface VnR complex in vitro. Stimulation of human dermal microvascular endothelial cells in vitro with agents that stimulate protein kinase C resulted in dose- and time-dependent increases in expression of alpha v and beta 3 integrin chains. Additionally, stimulation with basic fibroblast growth factor induced similar increases, but stimulation with transforming growth factor-beta or interleukin-1 alpha failed to increase VnR expression. Increases in cell-surface VnR expression also correlated with an increased ability of microvascular endothelial cells to bind to vitronectin, but not fibronectin-coated surfaces. Although increases in cell-surface expression of beta 3 paralleled increases in expression of cell-surface alpha v, regulation of mRNA expression was distinct for each chain. These data suggests that microvascular endothelial cells express the VnR complex in vivo, that the cell-surface expression of this integrin on dermal microvascular endothelial cells can be regulated, and that this regulation may be important in cell adherence, cell migration, and wound healing.

Blotting, Northern↗
PubMed1991

Studies of the modulation of MHC antigen and cell adhesion molecule expression on human dermal microvascular endothelial cells.

Interactions between leukocytes and endothelial cells, particularly in the microvasculature, are important for the initiation and regulation of tissue inflammation. These interactions are regulated by the recognition of specific cell adhesion molecules (CAM) on both leukocytes and endothelial cells. In this study, we examined the modulation of cell surface expression of MHC antigens and the CAM intercellular adhesion molecule 1 (ICAM-1), lymphocyte function antigen 3 (LFA-3), and CD44 on human dermal microvascular endothelial cells (HDMEC) both grown in monolayers and differentiated into capillary-like structures on the basement membrane-like substrate matrigel. HDMEC grown in monolayers or differentiated on matrigel express comparable cell surface MHC class I, LFA-3, CD44, and ICAM-1. ICAM-1, but not LFA-3 or CD44, was increased in expression in a dose- and time-dependent manner by interleukin 1 (IL-1) alpha, tumor necrosis factor (TNF) alpha, lipopolysaccharide (LPS), or interferon (IFN) gamma. Comparable upregulation was observed both in cells grown in monolayers and cells differentiated on matrigel. IL-1 alpha, TNF alpha, and LPS increased ICAM-1 expression on average 100-200% whereas IFN gamma was somewhat less potent. Comparative studies with human umbilical vein endothelial cells (HUVEC) demonstrated consistently lower levels of ICAM-1 expression on HUVEC, but greater increases after cytokine stimulation. Pretreatment with dexamethasone or transforming growth factor (TGF) beta did not affect baseline expression of ICAM-1 or inhibit upregulation of ICAM-1 on HDMEC by IL-1 alpha, TNF alpha, LPS, or IFN gamma. Both IFN gamma and TNF alpha, but not IL-1 alpha increased MHC class I expression, whereas only IFN gamma induced the expression of HLA-DR on HDMEC. The effect of IL-1 alpha, TNF alpha, or IFN gamma was inhibited by antibody to the specific cytokine, but was unaffected by antibody to other cytokines. Additionally, IFN alpha or beta inhibited upregulation of HLA-DR by IFN gamma, but had no effect on the increased MHC class I or ICAM-1 expression mediated by this cytokine. These data demonstrate that the expression of CAM and MHC antigens on small vessel-derived endothelial cells is different from that observed on large-vessel HUVEC, is regulated by the presence of multiple cytokines operating via distinct pathways, and the expression and regulation of these proteins appear to be similar on cells that have been grown in monolayers to those morphologically differentiated into blood vessel-like structures.

Cell Adhesion Molecules↗
PubMed1991

Cell adhesion molecules and cutaneous inflammation.

Cutaneous inflammation is characterized by the infiltration of leukocytes such as polymorphonuclear neutrophils (PMNs), lymphocytes, and monocytes into the epidermis, dermis, or subcutaneous tissue in response to infectious or immunologic stimuli, in wound healing, or in response to trauma. In recent years, it has been found that cell-surface proteins on leukocytes, endothelial cells, and keratinocytes are critical elements in the initiation and evolution of cutaneous inflammation. In order for peripheral blood leukocytes to leave the circulatory system and enter tissue parenchyma, they must first bind to endothelial cells, pass between them, and traverse the vascular basement membrane. In this article we will examine both leukocyte-endothelial cell binding and evidence indicating that various cell-surface molecules present on leukocytes and endothelial cells, known as cell adhesion molecules (CAMs), interact with one another in specific fashion. This interaction or binding is a critical occurrence and its inhibition leads to downregulation of inflammation. Furthermore, some CAMs can be either induced or upregulated on leukocytes and endothelial cells by various proinflammatory cytokines. This tends to upregulate inflammation. It has become increasingly clear that the time-course of inflammation and its exquisite anatomic specificity are related to the regulation of expression of CAMs.

Animals↗
PubMed1990

Prevalence of thyroid abnormalities in patients with dermatitis herpetiformis and in control subjects with HLA-B8/-DR3.

PURPOSE: The prevalence of thyroid dysfunction as measured by the presence of overt thyroid disease, abnormal results of thyroid function tests, or antithyroid antibodies was compared in patients with dermatitis herpetiformis (DH) and a normal control group who had the HLA-B8/-DR3 haplotype. PATIENTS AND METHODS: The study population consisted of 56 patients with DH and 26 control subjects with the HLA-B8/-DR3 haplotype. All were examined for thyroid function abnormalities and thyroid autoantibodies. RESULTS: Patients with DH had a statistically significant increase in the prevalence of abnormal thyroid function test results and autoantibodies: 32% versus 4% for controls (Z = 2.01, p less than 0.02). In patients with DH, hypothyroidism was the most common thyroid abnormality (12 of 56) followed by hyperthyroidism (four of 56). Two patients had normal thyroid function test results with thyroid autoantibodies. Risk factors for thyroid abnormalities in patients with DH were increasing age (chi 2 = 6.55, p less than 0.02, significant) and the presence of thyroid microsomal antibodies. The HLA-B8/-DR3 haplotype was not a risk factor for thyroid abnormalities. CONCLUSION: The findings suggest that thyroid disease is independently associated with DH. Examination of patients with DH should include thyroid function tests along with assays for antithyroid antibodies.

Adult↗
PubMed1990

Cell adhesion molecules.

Recently it has become recognized that cell adhesion is critical in many different cellular functions. The proteins involved in the cell-cell or cell-matrix interactions are known as cell adhesion molecules (CAMs). This article reviews some of the most important CAMs and emphasizes their importance in dermatology and in skin diseases.

Cell Adhesion Molecules↗
PubMed1990

Vasculitis.

Vasculitis may be defined as damage to blood vessels induced by pathologic processes, resulting in compromise of function of the organ in which the blood vessels reside. A large number of syndromes and disease processes exist in which vasculitis plays a key role. Selected vasculitic syndromes of special interest to dermatologists are discussed in this article.

Humans↗
PubMed1990

[Immunophenotypic analysis of human endothelial cells].

Very Little is known about the immunological attributes of human endothelial cells. In this study, we performed immunologic phenotypic analysis of cultured human dermal microvascular endothelial cells in comparison with human umbilical vein endothelial cells and examined the ability of various biologic response modifiers to alter the phenotypes. Using FACS analysis, both types of the cells appear to lack many of the cell surface markers of immunologically proficient cells, E.G. OKT4, OKT8, Leu7, FcIgG receptor, complement receptors, IL-2 receptor and HLA-Dr, but they possess beta 2-microglobulin and DAF. HLA-Dr antigens can be induced on both types of endothelial cells by gamma-IFN in a dose and time dependent manner. Both types of endothelial cells possess several kinds of Cell Adhesion Molecules (CAMs), such as ICAM-1, CD44, LFA-3, but not LFA-1 or CD2. ICAM-1 but not LFA-3 or CD44 can be upregulated by exposure of both types of endothelial cells to gamma-IFN, IL-1 and TNF. These data suggest that endothelial cells of the dermal microvasculature may play central roles in a variety of different cutaneous inflammation.

Antigens, Surface↗
PubMed1989

Polymyositis/dermatomyositis associated with dermatitis herpetiformis.

We describe 2 patients with dermatitis herpetiformis who developed polymyositis/dermatomyositis. On HLA typing, both patients were found to be HLA-B8, DR3 positive. The concurrence of these two relatively rare diseases, both associated with immunologic abnormalities, further supports the role of autoimmunity in their pathogenesis and indicates a possible common genetic basis. It also suggests that myositis may be more common in patients with dermatitis herpetiformis than in the general population.

Adult↗
PubMed1989

Cutaneous vasculitis: its relationship to systemic disease.

Necrotizing vasculitis may be localized to the skin or may involve multiple organs. Although the etiology of cutaneous necrotizing vasculitis is unknown, evidence suggests that circulating immune complexes play an important role. The most common clinical lesion seen is palpable purpura, which histologically demonstrates leukocytoclastic vasculitis. The majority of patients affected with cutaneous necrotizing vasculitis have a benign course.

Humans↗
PubMed1989

Dermatologic complications associated with administration of 2',3'-dideoxycytidine in patients with human immunodeficiency virus infection.

We describe a distinctive mucocutaneous eruption that occurred in 14 of 20 (70%) patients with human immunodeficiency virus infection while they were being treated with a new therapeutic agent, 2'3'-dideoxycytidine. A maculopapular eruption developed in these patients on day 10 or 11 of treatment. Seven of 14 patients, especially those receiving higher-dose therapy, also had systemic symptoms. In addition, oral ulcers developed in 9 of 14 patients on days 4 to 6 of therapy. The occurrence of the cutaneous and oral lesions correlated with dose, route, and schedule of administration of 2'3'-dideoxycytidine. In most instances the mucocutaneous lesions resolved even with continuation of therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Analysis of the interaction of human C5a and C5a des Arg with human monocytes and neutrophils: flow cytometric and chemotaxis studies.

C5a and C5a des Arg are potent complement-derived mediators that bind receptors on peripheral blood leukocytes and tissue-specific cellular elements to elicit and amplify inflammatory and immunomodulatory reactions. To study the interactions of C5a and C5a des Arg with these cells, fluorescein conjugates of these ligands were prepared by a new technique and their binding to monocytes, neutrophils, platelets, and endothelial cells was studied with flow cytometry. Fluoresceinated C5a produced neutrophil myeloperoxidase release and chemotaxis and also bound rabbit anti-C5a antibody much like native anaphylatoxin; likewise, fluoresceinated C5a des Arg demonstrated retention of biologic and antigenic activities. Both fluorescein-conjugated C5a and C5a des Arg bound to monocytes and neutrophils in a concentration-dependent, saturable, and homogeneous manner, but 10- to 15-fold higher concentrations of C5a des Arg were required to attain saturable binding of these leukocytes. Ligand binding was specifically inhibited by native purified human C5a in a concentration-dependent manner, while it was unaffected by C3a or N-formyl-methionyl-leucyl-phenylalanine-lysine. There was no evidence of a C5a receptor-negative subpopulation of monocytes or neutrophils. Moreover, comparative binding experiments with leukocytes from multiple normal volunteers showed that a greater percentage of monocytes than neutrophils bound C5a at less than saturable concentrations of ligand (P less than 0.05, 0.5 to 5.0 nM). A representative half-maximal binding of fluorescein-conjugated C5a (C5a des Arg) binding to monocytes and neutrophils was 1.2 nM (30 nM) and 2.6 nM (68 nM), respectively. In contrast, fluorescein-conjugated C5a did not specifically bind to human platelets or umbilical vein endothelial cells.

Blood Platelets↗
PubMed1989

Induction of morphologic differentiation of endothelial cells in culture.

Human endothelial cells when grown in cell culture assume a "cobblestone" morphology and do not form tubes or capillarylike structures. We have recently identified a culture substrate containing basement membrane-derived proteins that promotes morphologic differentiation of human umbilical vein and human dermal microvascular endothelial cells into capillarylike tubes. This differentiation is rapid, beginning within 1 h and is complete by 8-12 h. On electron microscopy these cells form a lumen, derived from remodeling of multiple cells and also by forming holes in the cytoplasm of individual cells. The endothelial cells no longer proliferate when cultured on this substrate known as matrigel, but can be induced to do so when cultured on fibronectin. We have also identified a critical molecular signal for endothelial cell differentiation induced by matrigel. Laminin, a prime constituent of matrigel, and to lesser extent collagen IV appear to be key elements in the differentiation of endothelial cells induced by matrigel.

Basement Membrane↗
PubMed1989

Inflammatory properties of human C5a and C5a des Arg/ in mast cell-depleted human skin.

C5a and its degradation product, C5a des Arg, elicit immediate cutaneous inflammatory reactions after intradermal injection. Histologically, these reactions are characterized by neutrophil-rich leukocytic infiltrates, leukocytoclasis, edema, and dermal mast cell degranulation. It has not been possible to assess in vivo the relative contributions of resident mast cells and circulating leukocytes to this reaction because the accumulation of leukocytes and degranulation of mast cells occur simultaneously after injection of these anaphylatoxins. To assess the role of mast cells in these inflammatory reactions, we have examined the reactivity of human skin selectively depleted of dermal mast cells by local corticosteroid treatment. Corticosteroid-treated skin became virtually devoid of dermal mast cells within 4-6 wk as assessed by light microscopy, immunofluorescence with fluorescein-conjugated avidin, or electron microscopy. Mast cell-depleted skin demonstrated normal vasopermeability and vasodilatory responsiveness to intradermal injection of histamine, but the reactivity of these sites to the mast cell secretagogue, morphine, was absent. Moreover, no clinical reactions were detectable in mast cell-depleted human skin after intradermal challenge with 50 ng of either C5a or C5a des Arg, despite the fact that biopsies of these sites revealed substantial, neutrophil-rich infiltrates. These infiltrates were qualitatively and quantitatively identical to C5a or C5a des Arg-induced infiltrates in mast cell replete skin. This experimental approach in vivo has allowed the independent analysis of the anaphylactogenic and chemoattractant activities of human C5a and C5a des Arg in human skin, demonstrated the importance of dermal mast cells in these clinical responses, and shown that leukocytes can accumulate at these injection sites directly in response to these mediators.

Adrenal Cortex Hormones↗