Ying-Ji Li

EM703 improves bleomycin-induced pulmonary fibrosis in mice by the inhibition of TGF-β signaling in lung fibroblasts

BackgroundFourteen-membered ring macrolides have been effective in reducing chronic airway inflammation and also preventing lung injury and fibrosis in bleomycin-challenged mice via anti-inflammatory effects. EM703 is a new derivative of erythromycin (EM) without the bactericidal effects. We investigated the anti-inflammatory and antifibrotic effects of EM703 in an experimental model of bleomycin-induced lung injury and subsequent fibrosis in mice.MethodsSeven-week-old male ICR mice were used. All experiments used eight mice/group, unless otherwise noted in the figure legends. Bleomycin was administered intravenously to the mice on day 0. EM703 was orally administered daily to mice. All groups were examined for cell populations in the bronchoalveolar lavage (BAL) fluid and for induction of messenger RNA (mRNA) of Smad3 and Smad4 in the lung tissues by reverse transcriptase (RT)-polymerase chainreaction (PCR) on day 7. Fibroblastic foci were assessed histologically, and the hydroxyproline content was chemically determined in the lung tissues on day 28. We performed assay of proliferation and soluble collagen production, and examined the induction of mRNA of Smad3 and Smad4 by RT-PCR in murine lung fibroblast cell line MLg2908. We also examined Smad3, Smad4 and phosphorylated Smad2/3 (p-Smad2/3) protein assay by western blotting in MLg2908.ResultsBleomycin-induced lung fibrosis, and the infiltration of macrophages and neutrophils into the airspace were inhibited by EM703. The expression of Smad3 and Smad4 mRNA was clearly attenuated by bleomycin, but was recovered by EM703. EM703 also inhibited fibroblast proliferation and the collagen production in lung fibroblasts induced by Transforming growth factor-beta (TGF-β). The expression of Smad3 and Smad4 mRNA in murine lung fibroblasts disappeared due to TGF-β, but was recovered by EM703. EM703 inhibited the expression of p-Smad2/3 and Smad4 protein in murine lung fibroblasts induced by TGF-β.ConclusionThese findings suggest that EM703 improves bleomycin-induced pulmonary fibrosis in mice by actions of anti-inflammation and regulation of TGF-β signaling in lung fibroblasts.

Role of oxidative stresses induced by diesel exhaust particles in airway inflammation, allergy and asthma: their potential as a target of chemoprevention.

Epidemiological studies have shown that particulate air pollutants, such as diesel exhaust particles (DEPs) are implicated in the increased incidence of allergic airway disorders. DEPs induce and exaggerate allergic airway inflammation in vitro and in vivo. Studies of molecular mechanisms have focused on the role of reactive oxygen species (ROS) generated directly and indirectly by exposure to DEPs. The ROS play an important role in proinflammatory reaction in airways. Nuclear erythroid 2 P45-related factor Nrf2 is a key transcription factor that regulates host antioxidant and contributes to regulate airway inflammation and exacerbation of allergic inflammation induced by DEPs. The authors demonstrated that DEPs-induced oxidants stress and resultant inflammatory changes were blocked by antioxidants such as N-acetyl cysteine (NAC). Therefore, chemoprevention against DEPs health effects in susceptible individuals may become a choice for future environmental protection policy.

AIRWAY INFLAMMATORY RESPONSES TO OXIDATIVE STRESS INDUCED BY LOW-DOSE DIESEL EXHAUST PARTICLE EXPOSURE DIFFER BETWEEN MOUSE STRAINS

Low-dose diesel exhaust particle (DEP) exposure induces airway inflammation and exaggerates asthmatic responses in mice, but it is unclear whether strains differ in their susceptibility to adverse effects from low-dose DEP exposure. The authors used BALB/c and C57BL/6 mouse strains to search for genetically based differences in response to low-dose DEP (100 µg/m3) exposure in terms of airway inflammatory response. The macrophage count in bronchoalveolar lavage (BAL) fluid soon after DE exposure began was significantly greater in C57BL/6 mice (P < .05) than that in BALB/c mice. The count did not increase significantly in BALB/c mice until later. Heme oxygenase-1 (HO-1) mRNA expression and protein production in lung tissues soon after exposure began were more marked in BALB/c mice than in C57BL/6 mice, but the reverse was true later on. The increases in interleukin (IL)-1β and interferon (IFN)-γ levels in BAL fluid after DE exposure were significant only in BALB/c mice; there were significantly increases in monocyte chemoattractant protein (MCP)-1, IL-12, IL-10, IL-4, and IL-13 in both strains, but these were more marked in C57BL/6 mice. These interstrain differences in airway inflammatory response after DE exposure were significantly attenuated by antioxidant N-acetylcysteine (NAC) treatment. Changes in airway hyperresponsiveness were independent of the airway inflammation induced by low-dose DEP. Thus, in BALB/c mice, innate immunity may play a central role in DE exposure response, whereas in C57BL/6 mice Th2-dominant responses play a central role. Low-dose DEP exposure induces airway inflammatory responses that differ among strains, and these differences may be caused by differences in sensitivity to oxidative stress.

Prostaglandin E2 Inhibits Human Lung Fibroblast Chemotaxis through Disparate Actions on Different E-Prostanoid Receptors

The migration of fibroblasts is believed to play a key role in both normal wound repair and abnormal tissue remodeling. Prostaglandin E (PGE)(2), a mediator that can inhibit many fibroblast functions including chemotaxis, was reported to be mediated by the E-prostanoid (EP) receptor EP2. PGE(2), however, can act on four receptors. This study was designed to determine if EP receptors, in addition to EP2, can modulate fibroblast chemotaxis. Using human fetal lung fibroblasts, the expression of all four EP receptors was demonstrated by Western blotting. EP2-selective and EP4-selective agonists inhibited both chemotaxis toward fibronectin in the blindwell assay and migration in a wound-closure assay. In contrast, EP1-selective and EP3-selective agonists stimulated cell migration in both assay systems. These results were confirmed using EP-selective antagonists. The role of both EP2 and EP4 receptors in mediating the PGE(2) inhibition of chemotaxis was also confirmed by small interfering RNA suppression. Furthermore, the role of EP receptors was confirmed by blocking the expected signaling pathways. Taken together, these results demonstrate that PGE(2) can act on multiple EP receptors in human lung fibroblasts, to exert disparate effects. Alterations in EP receptor expression may have the potential to alter PGE(2) action. Targeting specific EP receptors may offer therapeutic opportunities in conditions characterized by abnormal tissue repair and remodeling.

Nrf2 is closely related to allergic airway inflammatory responses induced by low-dose diesel exhaust particles in mice.

We have recently reported that disruption of nuclear erythroid 2 P45-related factor 2 (Nrf2) enhances susceptibility to airway inflammatory responses induced by low-dose diesel exhaust particles (DEP) in mice. C57BL/6 Nrf2 knockout (Nrf2(-/-)) mice and wild-type (Nrf2(+/+)) mice were further exposed to low-dose DEP for 7h/day, 5 days/week, for a maximum of 8 weeks. After exposure to DEP for 5 weeks, allergic airway inflammation was generated in the mice by intraperitoneal sensitization with OVA followed by intranasal challenge. Nrf2(-/-) mice exposed to relatively low-dose DEP showed significantly increased percentage changes relative to the OVA alone group in terms of airway hyperresponsiveness (AHR) and inflammatory cells, levels of IL-5 and thymus and activation regulated chemokine (TARC) in bronchoalveolar lavage (BAL) fluid than did Nrf2(+/+) mice. Lung tissues of Nrf2(-/-) mice after DEP exposure showed inflammatory cell infiltrates, and increased PAS staining-positive mucus cell hyperplasia. In contrast, the percentage changes relative to the OVA group in the reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio in whole blood was higher in Nrf2(+/+) mice than in Nrf2(-/-) mice. By using Nrf2(-/-) mice, it was shown for the first time that relatively low-dose DEP exposure induces oxidant stress, and that host anti-oxidant responses play a key role in the development of DEP-induced exacerbation of allergic airway inflammation.

Association of smoking status, insulin resistance, body mass index, and metabolic syndrome in workers: A 1-year follow-up study

SUMMARY OBJECTIVE We performed a 1-year follow-up study to determine the effects of smoking status and insulin resistance on the prevalence of metabolic syndrome. METHODS This study included 2136 workers without metabolic syndrome at baseline who were followed for 1 year. The subjects were divided into four categories of smoking and work history, respectively. Insulin resistance was evaluated using the homeostasis model assessment for insulin resistance (HOMA-R). RESULTS The prevalence of metabolic syndrome after 1 year was 6.3%. A multiple logistic regression analysis showed that the current smokers category versus the non-smokers category, a 0.1-point increase in the HOMA-R score, a 1-point increase in the uric acid level, age, and body mass index were significantly correlated with increased odds for metabolic syndrome, yielding odds ratios (95% confidence intervals) of 1.61 (1.09-2.39), 1.14 (1.04-1.25), 1.31 (1.12-1.54), and 1.06 (1.03-1.09), and 1.23 (1.15-1.31), respectively. CONCLUSIONS Current smoking, insulin resistance, uric acid level, and age contributed positively to the prevalence of metabolic syndrome. In contrast, smoking cessation within 1 year and work history did not contribute to metabolic syndrome.

EM, EM703 inhibit NF-kB activation induced by oxidative stress from diesel exhaust particle in human bronchial epithelial cells: Importance in IL-8 transcription

Diesel exhaust particle (DEP) is the major components of PM2.5, and much attention has focused on PM2.5 in relation to adverse health effects, and many pulmonary diseases. In the present study, we used a human bronchial epithelial cell (HBEC) line to investigate the anti-inflammatory effects of erythromycin (EM) and EM703 - a new derivative of erythromycin without antibacterial effects on the expressions of IL-8 caused by DEP exposure. DEP showed a dose-dependent stimulatory effect on IL-8 product in HBEC. Increases of IL-8 expression by DEP stimulation were significantly blocked by both EM and EM703 pretreatment. Furthermore, NF-κB and Nrf2 activation, the antioxidant enzymes such as HO-1, NQO-1 mRNA expression were increased by DEP exposure and these increases were blocked by both of EM and EM703 pretreatment. Our results suggest that, EM and EM703 may have an inhibitory effect on expression inflammatory cytokines in HBEC induced by DEP not only as an anti-inflammation but also an antioxidant drug. EM and EM703 might contribute to chemical prevention of the risk of pulmonary diseases induced by oxidative stress from environmental pollutant, such as DEP.

Nrf2 Is a Protective Factor against Oxidative Stresses Induced by Diesel Exhaust Particle in Allergic Asthma

Epidemiological studies have shown that air pollutants, such as diesel exhaust particle (DEP), are implicated in the increased incidence of allergic airway disorders. In vitro studies of molecular mechanisms have focused on the role of reactive oxygen species generated directly and indirectly by the exposure to DEP. Antioxidants effectively reduce the allergic inflammatory effects induced by DEP both in vitro and in vivo. On the other hand, Nrf2 is a transcription factor essential for the inducible and/or constitutive expression of phase II and antioxidant enzymes. Disruption of Nrf2 enhances susceptibility to airway inflammatory responses and exacerbation of allergic inflammation induced by DEP in mice. Host responses to DEP are regulated by a balance between antioxidants and proinflammatory responses. Nrf2 may be an important protective factor against oxidative stresses induced by DEP in airway inflammation and allergic asthma and is expected to contribute to chemoprevention against DEP health effects in susceptible individuals.

Relationship among lifestyles, aging and psychological wellbeing using the General Health Questionnaire 12-items in Japanese working men

Introduction. The relationship among lifestyle, aging and psychological wellbeing was evaluated in Japanese working men. Methods. Self-administered questionnaire on six lifestyle factors and the General Health Questionnaire 12-item version (GHQ12) were administered to 3306 male workers. Health practice index (HPI) was calculated as a desirable lifestyle score by summing up each binary lifestyle score (0, 1), ranging from 0 to 6. To check validity of the study outcome, the authors repeated twice with 1 year interval. HPI was categorised into three groups by the score of 0–2, 3–4 and 5–6. Results. The number of subjects categorised by HPI was 532, 1967 and 807, respectively. The mean value of GHQ12 significantly decreased as the HPI increased by adjusting age. Multiple regression analysis was conducted to predict GHQ12 by six lifestyle scores, and age, sleep, night snacking and exercise were significantly related to GHQ12. Multiple logistic regression analysis was conducted and age in 50s, two-shift work, sleep, night snacking and exercise were significantly associated with GHQ12. Conclusion. Although cause–effect relationship cannot make clear, some of desirable health practices and aging were closely related to psychological wellbeing judged by GHQ12.

EM703, A NEW DERIVATIVE OF ERYTHROMYCIN, INHIBITS TRANSFORMING GRWTH FACTOR-β SIGNALING IN HUMAN LUNG FIBROBLASTS

Long-term, low-dose macrolide therapy has been proven to improve survival in patients with diffuse panbronchiolitis and cystic fibrosis, although the mechanisms by which it does so remain unknown. To elucidate the molecular mechanisms of the anti-inflammatory effects of macrolides, the authors examined the effects of erythromycin (EM-A) and new derivative EM703 on transforming growth factor (TGF)-β /Smad signaling fibroblasts. EM-A and EM703 each inhibited fibroblast proliferation and the collagen production in human lung fibroblasts induced by TGF-β. EM-A and EM703 inhibited the augmentation of Smad3 mRNA induced by TGF-β. Smad7 mRNA was inhibited by TGF-β, but augmented by coincubation with EM-A or EM703. EM-A and EM703 each inhibited p-Smad2/3 proteins induced by TGF-β. Smad7 protein inhibited by TGF-β restored beyond basal level by EM-A and EM703. These findings suggest that EM-A and EM703 inhibit TGF-β signaling in human lung fibroblasts via inhibition of p-Smad2/3 through recovery of Smad7 level.