Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S-1-P) are both low molecular weight lysophospholipid (LPL) ligands that are recognized by the Edg family of G protein-coupled receptors. In endothelial cells, these two ligands activate Edg receptors, resulting in cell proliferation and cell migration. The intercellular adhesion molecule-1 (ICAM-1, CD54) is one of many cell adhesion molecules belonging to the immunoglobulin superfamily. This study showed that LPA and S-1-P enhance ICAM-1 expression at both the mRNA and protein levels in human umbilical cord vein endothelial cells (HUVECs). This enhanced ICAM-1 expression in HUVECs was first observed at 2 h postligand treatment. Maximal expression appeared at 8 h postligand treatment, as detected by flow cytometry and Western blotting. Furthermore, the effects of S-1-P on ICAM-1 expression were shown to be concentration dependent. Prior treatment of HUVECs with pertussis toxin, a specific inhibitor of G(i), ammonium pyrrolidinedithiocarbamate and BAY 11-7082, inhibitors of the nuclear factor (NF)-kappaB pathway, or Clostridium difficile toxin B, an inhibitor of Rac, prevented the enhanced effect of LPL-induced ICAM-1 expression. However, pretreatment of HUVECs with exoC3, an inhibitor of Rho, had no effect on S-1-P-enhanced ICAM-1 expression. In a static cell-cell adhesion assay system, pretreatment of LPL enhanced the adhesion between HUVECs and U-937 cells, a human mononucleated cell line. The enhanced adhesion effect could be prevented by preincubation with a functional blocking antibody against human ICAM-1. These results suggest that LPLs released by activated platelets might enhance interactions of leukocytes with the endothelium through a G(i)-, NF-kappaB-, and possibly Rac-dependent mechanism, thus facilitating wound healing and inflammation processes.

BackgroundCigarette smoking cannot fully explain the epidemiologic characteristics of chronic obstructive pulmonary disease (COPD) in women, particularly for those who rarely smoke, but COPD risk is not less than men. The aim of our study is to investigate the relationship between second-hand smoke (SHS) exposure and chronic bronchitis in Taiwanese women.MethodsWe used Taiwan's National Health Insurance Bureau claims data in 1999, and cross-checked using criteria set by the American Thoracic Society; there were 33 women with chronic bronchitis, 182 with probable chronic bronchitis, and 205 with no chronic bronchitis during our interview time between 2000 and 2005. We measured second-hand smoke (SHS) exposure by self-reported measures (household users and duration of exposure), and validated this by measuring urinary cotinine levels of a subset subjects. Classification of chronic bronchitis was also based on spirometry defined according to the GOLD guidelines to get the severity of COPD.ResultsWomen who smoked and women who had been exposed to a lifetime of SHS were 24.81-fold (95% CI: 5.78-106.38) and 3.65-fold (95% CI: 1.19-11.26) more likely to have chronic bronchitis, respectively, than those who had not been exposed to SHS. In addition, there was a significant increasing trend between the severity of COPD and exposure years of SHS (p < 0.01). The population attributable risk percentages of chronic bronchitis for smokers and those exposed to SHS were 23.2 and 47.3% respectively.ConclusionsThese findings indicate that, besides cigarette smoking, exposure to SHS is a major risk factor for chronic bronchitis in Taiwanese women.

Cytokine-induced inflammation is the predominant underlying mechanism in chronic obstructive pulmonary disease (COPD). Genetic factors may play a pivotal role in the development of this disease. This study looked at the relationship between COPD and genetic polymorphisms in the genes encoding some of these cytokines in a Taiwanese population. The genetic polymorphisms examined in this study were tumor necrosis factor (TNF)-alpha(-308), TNF-alpha(+489), interleukin(IL)-1beta(-31), interleukin-1 receptor antagonist (IL-1 RN), and IL-6(-174). In total, 30 patients with COPD, 64 subjects at risk of COPD and 115 controls were recruited to the study between 1999 and 2003. DNA was collected from these subjects and analyzed by polymerase chain reaction with sequence-specific primers and restriction enzyme fragment length polymorphism analysis. The frequencies of cytokine genotypes in COPD cases and controls, respectively, were as follows: for G/G in TNF-alpha(-308), 76.7% and 83.5%; for G/G in TNF-alpha(+489), 76.7% and 68.7%; for C/T in IL-1beta(-31), 60.0% and 55.7%; for 4R/4R in IL-1 RN, 80.0% and 86.1%; and for G/G in IL-6(-174), 100.1% and 98.3%. There was no difference in the distribution of the frequencies of these genotypes and alleles between COPD cases and controls. Moreover, no association was found between these genetic polymorphisms in cytokines and COPD (regardless of COPD subtypes) with respect to cigarette smoking or pulmonary function tests. Despite this, smoking is still an important risk factor for developing COPD.