No abstract

The three-river source region (TRSR, including Yangtze, Yellow and Lancang rivers), located in the Qinghai-Tibetan Plateau, China, is a typical alpine zone with apparent ecosystem vulnerability and sensitivity. In this paper, we introduced many interdisciplinary factors, such as landscape pattern indices (Shannon diversity index and Shannon evenness index) and extreme climate factors (number of extreme high temperature days, number of extreme low temperature days, and number of extreme precipitation days), to establish a new model for evaluating the spatial patterns of ecosystem vulnerability changes in the TRSR. The change intensity (CI) of ecosystem vulnerability was also analyzed. The results showed that the established evaluation model was effective and the ecosystem vulnerability in the whole study area was intensive. During the study period of 2001-2011, there was a slight degradation in the eco-environmental quality. The Yellow River source region had the best eco-environmental quality, while the Yangtze River source region had the worst one. In addition, the zones dominated by deserts were the most severely deteriorated areas and the eco-environmental quality of the zones occupied by evergreen coniferous forests showed a better change. Furthermore, the larger the change rates of the climate factors (accumulative temperature of ≥10°C and annual average precipitation) are, the more intensive the CI of ecosystem vulnerability is. This study would provide a scientific basis for the eco-environmental protection and restoration in the TRSR.

Dendritic cell (DC) can be stimulated by both exogenous pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharide (LPS) and endogenous damage-associated molecular patterns (DAMPs) such as high mobility group box-1 protein (HMGB1). MicroRNAs (miRNAs) act as post-transcriptional fine tuners of mRNA. Studies have focused mostly on the potential role of miRNAs in DCs maturation triggered by PAMPs, especially LPS, however, little is known about the regulatory mechanism underlying the effects of miRNAs in DC maturation mediated by DAMPs, including HMGB1. Here, we first profiled a miRNA microarray of DCs stimulated by HMGB1 and determined that the up-regulated miRNA miR-181a-5p may act as a regulatory miRNA in these cells. Computational algorithms predicted TNF-α 3′UTR to be targeted by miR-181a-5p, which was confirmed by the experiments involving luciferase reporters. In addition, we found that TNF-α mRNA was down-regulated by miR-181a-5p mimic, and significantly up-regulated by miR-181a-5p inhibitor. Taken together, we identified miR-181a-5p a negative regulator in HMGB1-induced immune responses by targeting TNF-α mRNA in DCs. Moreover, we suggested that miR-181a-5p may play a role in regulating DC responses to HMGB1 and serve as evidence indicating that novel therapies targeting miRNAs may be useful for treating immune dysfunction in the setting of sepsis.