Adhesion Molecule-1 mRNA Levels Research Articles

Phosphatidylinositol 3-Kinase Is a Key Regulator of Early Phase Differentiation in Keratinocytes

The survival and growth of epithelial cells depend on adhesion to the extracellular matrix. Because epidermal keratinocytes differentiate as they leave the basement membrane, an adhesion signal may regulate the initiation of differentiation. Phosphatidylinositol 3-kinase (PI3K) is a fundamental signaling molecule that regulates the adhesion signal. Transfection of a dominant negative form of PI3K into keratinocytes using an adenovirus vector resulted in significant morphological changes comparable to differentiation and the induction of differentiation markers, keratin (K) 1 and K10. In turn, transfection with the constitutively active form of PI3K almost completely abolished the induction of K1 and K10 by differentiation in suspension cultures using polyhydroxyethylmethacrylate-coated dishes. PI3K activity was lost in suspension culture, except by cells bearing the constitutively active form of PI3K. These data demonstrate that blockade of PI3K results in differentiation and that activation of PI3K prevents differentiation. Furthermore, expression of the dominant negative form of PI3K significantly inhibited keratinocyte adhesion to the extracellular matrix and reduced the surface expression of alpha(6) and beta(1) integrins in suspension culture. Moreover, expression of the active form of PI3K restored the mRNA levels of adhesion molecules that were reduced in suspension culture, including alpha(3), alpha(6), and beta(1) integrins, BP180, and BP230. In conclusion, loss of PI3K activity results in keratinocytes leaving the basement membrane and the initiation of a "default" differentiation mechanism.

Pattern of cytokine and adhesion molecule mRNA in hapten-induced relapsing colon inflammation in the rat.

We examined the mRNA expression of cytokines, chemokines, integrins, and selectins in colon lesions of rat colitis with a semi-quantitative RT-PCR assay. Rat colitis was induced by trinitrobenzene sulfonic acid (TNBS) in 50% ethanol. Within 24 h, an acute inflammation occurred with hyperemia, edema, necrosis and an intense infiltration of granulocytes in the mucosa. The lesion proceeded into a T-lymphocyte/monocyte-driven chronic inflammation for two weeks and healed in 6 weeks. An acute inflammation recurred at the same site when the recovered animals were systemically injected with TNBS. We isolated RNA from colon tissue at 24 h, 1, 2, 4, 6 weeks after TNBS treatment and from the relapsed animals. The mRNA for cytokines IL-1beta, IL-6, IL-10 and the chemokines CINC, MIP-1alpha, MCP-1 were significantly (P < 0.05) elevated and persisted for 2 weeks, decreased in 6 weeks and increased again during relapse. IFN-gamma mRNA stayed at control levels initially, but increased dramatically in the second weeks of chronic inflammation as well as in relapse. The mRNA levels of adhesion molecules, ICAM-1, VCAM-1, the mucosal homing integrin beta7 as well as P- and E-selectin were greatly enhanced between 1 and 3 weeks. The data showed that the chronically inflamed tissue expresses a time-dependent changing pattern of TH1 cytokines and adhesion molecules that maintain the infiltration and activation of inflammatory cells and tissue injury.

Intercellular Adhesion Molecule-1 Suppression in Skin by Topical Delivery of Anti-Sense Oligonucleotides

We topically applied 20 nucleotide phosphorothioate intercellular adhesion molecule-1 anti-sense oligodeoxynucleotide in a cream formulation. It effectively inhibited tumor necrosis factor-alpha-induced expression of intercellular adhesion molecule-1 in human skin transplanted on severe compromised immunodeficient mice. The effects were concentration dependent, sequence specific, and resulted from reduction of intercellular adhesion molecule-1 mRNA levels in the skin. Intravenous administration of the drug did not show pharmacologic effects, probably due to insufficient drug concentrations in skin. Topical delivery, however, produced a rapid and a significantly higher accumulation of oligodeoxynucleotide in the epidermis and dermis. The results strongly suggest that topically applied anti-sense oligonucleotides can be delivered to target sites in the skin and may be of considerable value in the treatment of psoriasis and other inflammatory skin disorders.

Chemokine and Cell Adhesion Molecule mRNA Expression and Neutrophil Infiltration in Lipopolysaccharide‐Induced Hepatitis in Ethanol‐Fed Rats

Neutrophil infiltration is a feature of alcoholic hepatitis (AH), and although the mechanism by which this occurs is unclear, it may involve a chemotactic gradient. We used lipopolysaccharide (LPS) to induce, in ethanol-fed rats, liver damage similar to that seen in AH. To our knowledge, this study is the first to examine the effect of ethanol on LPS-stimulated chemokine mRNA expression in this model. Hepatic cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1beta, MIP-2, and eotaxin mRNA levels were elevated 1 to 3 hr post-LPS in both groups. Maximal expression of MIP-2 and MCP-1 mRNA was higher in ethanol-fed rats 1 hr post-LPS, whereas CINC-2 mRNA expression was elevated above controls at 12 to 24 hr. Hepatic intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 mRNA levels were elevated in both groups at 1 hr, whereas L-selectin expression in ethanol-fed rats was elevated above controls at 12 to 24 hr. Hepatic neutrophil infiltration was highest during maximal hepatocyte necrosis. These data suggest that cell adhesion molecules, in conjunction with elevated cytokines and the subsequently induced chemokines, may assist in the formation of a chemotactic gradient within the liver, causing the neutrophil infiltration seen both in this model and possibly in AH.

Salicylates inhibit I kappa B-alpha phosphorylation, endothelial-leukocyte adhesion molecule expression, and neutrophil transmigration.

The expression of leukocyte adhesion molecules on endothelial cells is induced by TNF-alpha and other inflammatory cytokines. This induction of endothelial-leukocyte adhesion molecule-1, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 requires the transcription factor nuclear factor-kappa B (NF-kappa B). Recent work has suggested that some nonsteroidal anti-inflammatory agents, including sodium salicylate and aspirin, can inhibit NF-kappa B-dependent gene activation. We studied the effects of salicylates on expression of adhesion molecules in HUVECs. We found that sodium salicylate inhibited activation of NF-kappa B (p50/p65 and p65/p65) by preventing phosphorylation and subsequent degradation of the inhibitor 1 kappa B-alpha. Salicylate treatment had no effect on TNF-alpha-induced phosphorylation of the transcription factor ATF-2. Salicylate blocked the TNF-alpha-induced increase in mRNA levels of adhesion molecules and gave a dose-dependent inhibition of TNF-alpha-induced surface expression of vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 with higher doses required to inhibit endothelial-leukocyte adhesion molecule-1 expression. Indomethacin, a nonsalicylate cyclooxygenase inhibitor, had no effect on surface expression of adhesion molecules, suggesting that the effects were not due to inhibition of cyclooxygenase. Treatment of endothelial cell monolayers with sodium salicylate inhibited transendothelial migration of neutrophils but had no significant effect on neutrophil adhesion under flow conditions. The clinical importance of high-dose salicylates in inflammation may be due, in part, to the ability to prevent expression of inducible adhesion molecules and recruitment of leukocytes.

Cardiopulmonary Bypass, Myocardial Management, and Support Techniques

Leukocyte adhesion to vascular endothelium is an early step in inflammatory damage to tissues. To investigate the expression of endothelial adhesion molecules in the inflammatory response associated with cardiopulmonary bypass, we measured messenger ribonucleic acid (mRNA) encoding the adhesion molecules E-selectin and intercellular adhesion molecule-1 in intraoperative samples of cardiac tissue and skeletal muscle from infants undergoing cardiopulmonary bypass. Atrial tissue samples were obtained before and after bypass from 11 children and paired samples of rectus abdominis muscle from 15. mRNA was analyzed by ribonuclease protection with the use of nonmuscle actin as an internal control. Atrial E-selectin mRNA levels increased from before to after bypass (median increase 3.5-fold, p = 0.0002) in each of nine patients tested, and atrial intercellular adhesion molecule-1 mRNA increased in seven of nine patients (median, 2.1-fold, p = 0.025). In skeletal muscle, E-selectin mRNA increased in 11 of 12 patients (median 4.3-fold, p = 0.0018), and intercellular adhesion molecule-1 mRNA levels increased in 13 of 13 patients (median 3.2-fold, p = 0.013). E-selectin and intercellular adhesion molecule-1 induction in skeletal muscle occurred with or without circulatory arrest. We conclude that adhesion molecule mRNA induction occurs in cardiac and noncardiac tissue during cardiopulmonary bypass in man.