Ken Nakagawa

Adenovector-mediated gene transfer of lysophosphatidylcholine acyltransferase 1 attenuates oleic acid-induced acute lung injury in rats.

Objective: Lysophosphatidylcholine is generated through the hydrolysis of phosphatidylcholine by phospholipase A2 and reversely converted to phosphatidylcholine by lysophosphatidylcholine acyltransferase 1. Although lysophosphatidylcholine is a potent proinflammatory mediator and increased in several types of acute lung injuries, the role of lysophosphatidylcholine acyltransferase 1 has not yet been addressed. We aimed to investigate whether the exogenous expression of lysophosphatidylcholine acyltransferase 1 could attenuate acute lung injury. Design: Randomized, prospective animal study, including in vitro primary cell culture test. Setting: University medical center research laboratory. Subjects: Adult male Sprague-Dawley rats. Interventions: Recombinant adenoviruses carrying complementary DNA encoding lysophosphatidylcholine acyltransferase 1 or lacZ (Ad-lacZ) as a control was constructed. Alveolar type II cells were isolated from rats and cultured on tissue-culture inserts. Rats were pretreated with an endobronchial administration of the recombinant adenovirus. One week later, they were IV injected with oleic acid. The lungs were examined 4 hours post oleic acid. Measurements and Main Results: Adenoviruses carrying complementary DNA encoding lysophosphatidylcholine acyltransferase 1–infected alveolar type II cells showed lower lysophosphatidylcholine levels and a decreased percentage of cell death compared with Ad-lacZ-infected cells or noninfected cells after exposure to hydrogen peroxide for 1 hour. Compared with Ad-lacZ plus oleic acid–treated lungs, adenoviruses carrying complementary DNA encoding lysophosphatidylcholine acyltransferase 1 plus oleic acid–treated lungs showed a lower wet-to-dry lung weight ratio, a higher lung compliance, lower lysophosphatidylcholine contents, higher phosphatidylcholine contents, and a lower apoptosis ratio of alveolar type II cells. Histological scoring revealed that the adenoviruses carrying complementary DNA encoding lysophosphatidylcholine acyltransferase 1–treated lungs developed oleic acid–induced lung injuries that were attenuated compared with those of Ad-lacZ-treated lungs. Conclusions: Exogenous expression of lysophosphatidylcholine acyltransferase 1 protects alveolar type II cells from oxidant-induced cell death in vitro, and endobronchial delivery of a lysophosphatidylcholine acyltransferase 1 transgene effectively attenuates oleic acid–induced acute lung injury in vivo. These results suggest that lysophosphatidylcholine acyltransferase 1 plays a protective role in acute lung injury.

p53 Signaling Pathway Polymorphisms Associated With Emphysematous Changes in Patients With COPD

Background The p53 signaling pathway may be important for the pathogenesis of emphysematous changes in the lungs of smokers. Polymorphism of p53 at codon 72 is known to affect apoptotic effector proteins, and the polymorphism of mouse double minute 2 homolog (MDM2) single nucleotide polymorphism (SNP)309 is known to increase MDM2 expression. The aim of this study was to assess polymorphisms of the p53 and MDM2 genes in smokers and confirm the role of SNPs in these genes in the pathogenesis of pulmonary emphysema. Methods This study included 365 patients with a smoking history, and the polymorphisms of p53 and MDM2 genes were identified. The degree of pulmonary emphysema was determined by means of CT scanning. SNPs, MDM2 mRNA, and p53 protein levels were assessed in human lung tissues from smokers. Plasmids encoding p53 and MDM2 SNPs were used to transfect human lung fibroblasts (HLFs) with or without cigarette smoke extract (CSE), and the effects on cell proliferation and MDM2 promoter activity were measured. Results The polymorphisms of the p53 and MDM2 genes were associated with emphysematous changes in the lung and were also associated with p53 protein and MDM2 mRNA expression in the lung tissue samples. Transfection with a p53 gene‐coding plasmid regulated HLF proliferation, and the analysis of P2 promoter activity in MDM2 SNP309‐coding HLFs showed the promoter activity was altered by CSE. Conclusions Our data demonstrated that p53 and MDM2 gene polymorphisms are associated with apoptotic signaling and smoking‐related emphysematous changes in lungs from smokers.

Sirt1 expression is associated with CD31 expression in blood cells from patients with chronic obstructive pulmonary disease

BackgroundCigarette smoke induced oxidative stress has been shown to reduce silent information regulator 1 (Sirt1) levels in lung tissue from smokers and patients with COPD patients. Sirt1 is known to inhibit endothelial senescence and may play a protective role in vascular cells. Endothelial progenitor cells (EPCs) are mobilized into circulation under various pathophysiological conditions, and are thought to play an important role in tissue repair in chronic obstructive lung disease (COPD). Therefore, Sirt1 and EPC-associated mRNAs were measured in blood samples from patients with COPD and from cultured CD34+ progenitor cells to examine whether these genes are associated with COPD development.MethodsThis study included 358 patients with a smoking history of more than 10 pack-years. RNA was extracted from blood samples and from CD34+ progenitor cells treated with cigarette smoke extract (CSE), followed by assessment of CD31, CD34, Sirt1 mRNA, miR-34a, and miR-126-3p expression by real-time RT-PCR.ResultsThe expression of CD31, CD34, Sirt1 mRNAs, and miR-126-3p decreased and that of miR-34a increased in moderate COPD compared with that in control smokers. However, no significant differences in these genes were observed in blood cells from patients with severe COPD compared with those in control smokers. CSE significantly decreased Sirt1 and increased miR-34a expression in cultured progenitor cells.ConclusionSirt1 expression in blood cells from patients with COPD could be a biomarker for disease stability in patients with moderate COPD. MiR-34a may participate in apoptosis and/or senescence of EPCs in smokers. Decreased expression of CD31, CD34, and miR-126-3p potentially represents decreased numbers of EPCs in blood cell from patients with COPD.

A three-microphone acoustic reflection technique using transmitted acoustic waves in the airway.

The acoustic reflection technique noninvasively measures airway cross-sectional area vs. distance functions and uses a wave tube with a constant cross-sectional area to separate incidental and reflected waves introduced into the mouth or nostril. The accuracy of estimated cross-sectional areas gets worse in the deeper distances due to the nature of marching algorithms, i.e., errors of the estimated areas in the closer distances accumulate to those in the further distances. Here we present a new technique of acoustic reflection from measuring transmitted acoustic waves in the airway with three microphones and without employing a wave tube. Using miniaturized microphones mounted on a catheter, we estimated reflection coefficients among the microphones and separated incidental and reflected waves. A model study showed that the estimated cross-sectional area vs. distance function was coincident with the conventional two-microphone method, and it did not change with altered cross-sectional areas at the microphone position, although the estimated cross-sectional areas are relative values to that at the microphone position. The pharyngeal cross-sectional areas including retropalatal and retroglossal regions and the closing site during sleep was visualized in patients with obstructive sleep apnea. The method can be applicable to larger or smaller bronchi to evaluate the airspace and function in these localized airways.