Pathogenesis of systemic sclerosis associated interstitial lung disease
JOURNAL OF SCLERODERMA AND RELATED DISORDERS
Authors: Nihtyanova, Svetlana, I; Denton, Christopher P.
Abstract
Systemic sclerosis is an autoimmune disease leading to vasculopathy and fibrosis of skin and internal organs. Despite likely shared pathogenic mechanisms, the patterns of skin and lung fibrosis differ. Pathogenesis of interstitial lung disease, a major cause of death in systemic sclerosis, reflects the intrinsic disease pathobiology and is associated with distinct clinical phenotypes and laboratory characteristics. The commonest histological pattern of systemic sclerosis-interstitial lung disease is non-specific interstitial pneumonia. Systemic sclerosis-interstitial lung disease pathogenesis involves multiple components, including susceptibility and triggering factors, which could be genetic or environmental. The process is amplified likely through ongoing inflammation and the link between inflammatory activity and fibrosis with IL6 emerging as a key mediator. The disease is driven by epithelial injury, reflected by markers in the serum, such as surfactant proteins and KL-6. In addition, mediators that are produced by epithelial cells and that regulate inflammatory cell trafficking may be important, especially CCL2. Other factors, such as CXCL4 and CCL18, point towards immune-mediated damage or injury response. Monocytes and alternatively activated macrophages appear to be important. Transforming growth factor beta appears central to pathogenesis and regulates epithelial repair and fibroblast activation. Understanding pathogenesis may help to unravel the stages of systemic sclerosis-interstitial lung disease, risks of progression and determinants of outcome. With this article, we set out to review the multiple factors, including genetic, environmental, cellular and molecular, that may be involved in the pathogenesis of systemic sclerosis-interstitial lung disease and the mechanisms leading to sustained fibrosis. We propose a model for the pathogenesis of systemic sclerosis-interstitial lung disease, based on the available literature.
Real-Time QCM-D Monitoring of the Adsorption-Desorption of Expansin on Lignin
LANGMUIR
Authors: Cui, Mei; Duan, Yuhao; Ma, Yuanyuan; Al-Shwafy, Khaled W. A.; Liu, Yudong; Zhao, Xudong; Huang, Renliang; Qi, Wei; He, Zhonghe; Su, Rongxin
Abstract
Expansin has nonhydrolytic disruptive activity and synergistically acts with cellulases to enhance the hydrolysis of cellulose. The adsorption-desorption of expansin on noncellulosic lignin can greatly affect the action of expansin on lignocellulose. In this study, three lignins with different sources (kraft lignin (KL), sodium lignin sulfonate (SLS), and enzymatic hydrolysis lignin (EHL)) were selected as the substrates. The real-time adsorption-desorption of Bacillus subtilis expansin (BsEXLX1) on lignins was monitored using quartz crystal microgravimetry with dissipation (QCM-D). The effects of temperature and Tween 80 on the adsorption-desorption behaviors were also investigated. The results show that BsEXLX1 exhibited high binding ability on lignin and achieved maximum adsorption of 283.2, 273.8, and 266.9 ng cm(-2) at 25 degrees C on KL, SLS, and EHL, respectively. The maximum adsorption decreased to 148.2-192.8 ng cm(-2) when the temperature increased from 25 to 45 degrees C. Moreover, Tween 80 competitively bound to lignin and significantly prevented expansin adsorption. After irreversible adsorption of Tween 80, the maximum adsorption of BsEXLX1 greatly decreased to 33.3, 37.2, and 10.3 ng cm(-2) at 25 degrees C on la, SLS, and EHL, respectively. Finally, a kinetic model was developed to analyze the adsorption- desorption process of BsEXLX1. BsEXLX1 has a higher adsorption rate constant (k(A)) and a lower desorption rate constant (k(D)) on KL than on SLS and EHL. The findings of this study provide useful insights into the adsorption-desorption of expansin on lignin.