Resistance Against the Membrane Attack Complex of Complement Induced in Porcine Endothelial Cells with a Galα(1–3)Gal Binding Lectin: Up-Regulation of CD59 Expression

Abstract

Endothelial cells (EC) play central roles in vascular physiology and pathophysiology. EC activation results in proinflammatory activities with production of cytokines and expression of adhesion molecules. However, we have shown before in a model of xenotransplantation that prolonged stimulation of porcine EC with human anti-porcine IgM natural Abs can activate the cells to become resistant against cytotoxicity by the membrane attack complex of complement (MAC). Now we report the major characteristics of induction and maintenance of resistance elicited in porcine EC with Bandeiraea simplicifolia lectin that binds terminal galα(1–3)gal. Lectin-treated cells underwent little or no cytotoxicity and PGI2 release when exposed to MAC. Induction of resistance required incubation of the EC with lectin for 4 h but was not fully manifested until 16 h later. Most of the initially bound lectin remained on the cell surface for >60 h. EC-bound lectin did not inhibit binding of IgM natural Abs or activation and binding of C components, including C9, but a C-induced permeability channel of reduced size was present. Induction of resistance required protein synthesis, developed slowly, and was associated with up-regulation of expression of mRNA for the MAC inhibitor CD59 and membrane-associated CD59 protein. Resistance lasted at least 3 days, and the cells regained normal morphology and were metabolically active. This induced resistance may have a physiologic counterpart that might be amenable to pharmacologic manipulation in vascular endothelium pathophysiology.

Interleukin-4 Induces Up-regulation of Endothelial Cell Claudin-5 through Activation of FoxO1

“…Many substances are able to adversely modify the EC junction, including thrombin (23), antibodies and EC antigen-binding lectins (11,13), and the membrane attack complex of complement (24). Because the injury caused by complement can be prevented by IL-4 (5), we hypothesized that IL-4 modifies one or more components of the junction so that the EC monolayer can resist the deleterious effect of complement.…”

“…Treatment with Cytokines and Inhibitors-ECs were explanted from pig aortae and cultured and identified as described previously (11). Experiments were performed with EC monolayers from five different preparations in passages 3 to 7, 2, to 3 days post-confluence in gelatin-coated plates (Corning).…”

Endothelial Cell Protection by Dextran Sulfate: A Novel Strategy to Prevent Acute Vascular Rejection in Xenotransplantation

“…Accommodation is dependent on the expression of protective genes by the graft vasculature, and HO-1 contributes in a critical manner to this step (6,7). The initial stimulus promoting accommodation in preference to rejection is still unknown, but various studies support the fact that anti-EC Abs can initiate cytoprotective changes (8)(9)(10). These data also show that the endothelium is a key component in AVR, and recent findings confirm that this disease is caused by an active metabolic process and not by apoptosis of EC's (11).…”

IL‐4 induces protection of vascular endothelial cells against killing by complement and melittin through lipid biosynthesis

“…EC from pig aortae were cultured and identified as previously described [39]. We performed experiments with cells in passages 3 to 7, 2 to 3 days post-confluence, in gelatin-coated Costar tissue culture plates as follows: 48-well plates for EC killing, membrane permeability, and ATP content; 24-well plates for flow cytometry and cholesterol assay; and 15-cm dishes for proton nuclear magnetic resonance (pNMR) studies (Corning, Corning, NY, USA).…”