Comparison of the action of transforming growth factor-beta 1 and interleukin-1 beta on matrix metabolism in the culture of porcine endothelial cells

Gene expression of endothelial cells due to interleukin-1 beta stimulation and neutrophil transmigration

During the inflammatory response, endothelial cell (EC) functions and mechanics change dramatically. To understand these responses, the authors analyzed changes in EC gene expression in an in vitro model of inflammation using cDNA microarrays. After interleukin-1 beta (IL1beta) stimulation, over 2500 genes were differentially expressed, of which approximately 2000 had not been previously identified by microarray studies of IL1beta stimulation in human umbilical vein endothelial cells (HUVECs). Functional grouping of these genes according to gene ontologies revealed genes associated with apoptosis, cell cycle, nuclear factor (NF)-kappa B cascade, chemotaxis, and immune response. Interestingly, claudin-1, known to exist in endothelial cell-cell junctions was up-regulated, but claudin-5 and occludin, which also exist in EC junctions, were down-regulated. Pre-b-cell colony enhancing factor (PBEF), a cytokine which may play a role in regulating endothelial permeability, was also up-regulated following IL1beta stimulation. Neutrophil transmigration across IL1beta-stimulated ECs did not induce changes in EC gene expression as strongly as IL1beta stimulation alone. Nineteen genes after 1 h and 22 genes after 3 h of neutrophil application were differentially expressed. These results indicate that, in terms of transcriptional effects on ECs, neutrophil transmigration is a relatively small perturbation in comparison to the background of large scale changes induced in ECs by cytokine stimulation. Supplementary materials are available for this article. Go to the publisher's online edition of Endothelium for the following free supplementary resources: supplementary figures and tables.

Differential regulation of biglycan and decorin synthesis by connective tissue growth factor in cultured vascular endothelial cells

It is possible that connective tissue growth factor (CTGF) serves as either an independent regulator or a downstream effector of transforming growth factor-beta (TGF-beta) on the proteoglycan synthesis in vascular endothelial cells. Since TGF-beta regulates endothelial proteoglycan synthesis in a cell density-dependent manner, dense and sparse cultures of bovine aortic endothelial cells were metabolically labeled with [(35)S]sulfate or (35)S-labeled amino acids in the presence of CTGF, and the labeled proteoglycans were characterized by biochemical techniques. The results indicate that CTGF suppresses the synthesis of biglycan but newly induced that of decorin in the cells when the cell density is low; in addition, no change was observed in the hydrodynamic size and the glycosaminoglycan chain length of these two small chondroitin/dermatan sulfate proteoglycans. The regulation of endothelial proteoglycan synthesis by CTGF is completely different from that by TGF-beta, suggesting that CTGF is not a downstream effector of TGF-beta but an independent regulator in vascular endothelial cells with respect to the proteoglycan synthesis.

Synthesis of sulfated proteoglycans by bovine glomerular endothelial cells in culture

It has been suggested that proteinuria is caused by alterations of the charge selectivity of the basement membrane and/or the epithelial cell layer (podocytes). However, recent findings suggest that the endothelial luminal surface coat, consisting of proteoglycans with their connected glycosaminoglycan (GAG) branches and glycoproteins, may contribute to the permselectivity. Therefore, we wanted to investigate the effects on endothelial GAG synthesis during normal and pathological conditions. We treated glomerular endothelial cell cultures with puromycin aminonucleoside (PAN, a nephrosis-inducing agent) or interleukin-1beta (IL-1beta) for a total of 72 h and compared the metabolic turnover and incorporation of [(35)S]sulfate during the last 2 days. In control cultures, the GAG content in the media supernatants increased 66 +/- 6% (mean +/- SE) between 12 and 42 h of incubation with radioactivity (P < 0.01, n = 8). The content of (35)S-labeled GAGs in the media was reduced by 31 +/- 1% by PAN (P < 0.001, n = 8) and increased by 141 +/- 15% by 10 U/ml IL-1beta (P < 0.01, n = 8). Treatment with enzymes revealed a dominance of heparan, chondroitin, and dermatan sulfate GAGs. Thus the glomerular endothelial cell production of GAGs was increased by IL-1beta and reduced by PAN. Therefore, it is conceivable that certain nephrotic conditions may be due to endothelial dysfunction, rather than other renal causes.