RESUMO
A number of previous studies have demonstrated the pivotal role of PI3K/AKT signalling in cigarette smoke (CS)-induced emphysema, where phosphoinositide dependent protein kinase 1 (PDK1) is a critical component of this pathway. Therefore, the present study aimed to investigate the effects of a PDK1 inhibitor (GSK-2334470) on the expression levels of PI3K, AKT, cyclin-dependent kinase inhibitor 2A (p16) and LC3B in a CS + CS extract (CSE)-induced mouse emphysema model. CS exposure and intraperitoneal injections of CSE were combined for 4 weeks to establish an emphysema model. Mice (n=35) were randomly divided into the normal control, emphysema (CS), PI3K inhibitor (CS3) and PDK1 inhibitor (CS1) groups. Immunohistochemistry staining of lung tissues was used to measure the expression of the PI3K, PDK1 and AKT proteins in airway epithelial tissues. Immunofluorescence staining was also used to measure the levels of p16 and LC3BII protein expression in the airway epithelial tissues. In addition, PI3K, PDK1, AKT, p16 and LC3B protein expression was semi-quantified using western blotting. The expression of PDK1, PI3K and AKT proteins in the airway epithelial tissues was significantly increased in the CS + CSE group compared with that in the control group. The expression levels of p16 and LC3B were also increased as well in the CS + CSE group compared with those in the control group. The expression levels of PI3K, PDK1, AKT, LC3B and p16 in the airway epithelial tissues of the CS3 group were lower compared with those in the CS + CSE group. A decrease in the expression levels of PDK1, AKT, p16 and LC3B in the airway epithelial tissues of the CS1 group compared with those in the CS + CSE group was also observed. However, there were no significant differences in the expression levels of PI3K between the CS1 and the CS groups. The present study concluded that the inhibition of PDK1 can potentially reduce autophagy and cell senescence by downregulating the expression of PI3K/AKT pathway related proteins in airway epithelial cells, thereby protecting against CS + CSE-induced emphysema in mice.
RESUMO
Exergy analysis, as a core evaluation tool to improve energy efficiency and system sustainability, has been applied in various fields over the last decades, leading to a significant increase of exergy-related publications. However, the existing reviews only analyzed part of publications related to a specific topic and lack a systematic analysis. To fill this research gap, a coupled bibliometric analysis and knowledge map method was conducted on 13,941 exergy-related publications during 1997-2020. Results show that publications increased from 54 in 1997 to 1976 in 2020. Journal of Energy is the most productive journals (1543 publications), and Energy & Fuels is the most popular subject category (9204 publications). Three developing countries in Asia (China, Iran, and Turkey) are the most productive, accounting for 45.87%. The main research objects and methods in this field were identified by cluster analysis. Furthermore, timeline analysis and burst detection analysis show that the new research hotspots or research frontiers will focus on organic Rankine cycle, building industry, multi-objective optimization, and sustainable development. This study further pointed out the future direction of the exergy field: in-depth application of the coupled exergy and exergoeconomic analysis; technologies development for efficient utilization of renewable energy, clean energy, and waste heat; enrichment of exergy framework incorporating environmental perspectives and mathematical methods; adaptation of theoretical research; and system optimization to the needs of social development. Through the review of exergy-related publications, results of this study can help to better identify the research hotspots and provide a valuable reference for future research.