Arginase2 mediates contrast-induced acute kidney injury via facilitating nitrosative stress in tubular cells.

Contrast-induced acute kidney injury(CI-AKI) is the third cause of AKI. Although tubular injury has been regarded as an important pathophysiology of CI-AKI, the underlying mechanism remains elusive. Here, we found arginase2(ARG2) accumulated in the tubules of CI-AKI mice, and was upregulated in iohexol treated kidney tubular cells and in blood samples of CI-AKI mice and patients, accompanied by increased nitrosative stress and apoptosis. However, all of the above were reversed in ARG2 knockout mice, as evidenced by the ameliorated kidney dysfunction and the tubular injury, and decreased nitrosative stress and apoptosis. Mechanistically, HO-1 upregulation could alleviate iohexol or ARG2 overexpression mediated nitrosative stress. Silencing and overexpressing ARG2 was able to upregulate and downregulate HO-1 expression, respectively, while HO-1 siRNA had no effect on ARG2 expression, indicating that ARG2 might inhibit HO-1 expression at the transcriptional level, which facilitated nitrosative stress during CI-AKI. Additionally, CREB1, a transcription factor, bound to the promoter region of ARG2 and stimulated its transcription. Similar findings were yielded in cisplatin- or vancomycin-induced AKI models. Taken together, ARG2 is a crucial target of CI-AKI, and activating CREB1/ARG2/HO-1 axis can mediate tubular injury by promoting nitrosative stress, highlighting potential therapeutic strategy for treating CI-AKI.

Identification and validation of hub genes in drug induced acute kidney injury basing on integrated transcriptomic analysis.

Background: Drug-induced acute kidney damage (DI-AKI) is a clinical phenomenon of rapid loss of kidney function over a brief period of time as a consequence of the using of medicines. The lack of a specialized treatment and the instability of traditional kidney injury markers to detect DI-AKI frequently result in the development of chronic kidney disease. Thus, it is crucial to continue screening for DI-AKI hub genes and specific biomarkers. Methods: Differentially expressed genes (DEGs) of group iohexol, cisplatin, and vancomycin's were analyzed using Limma package, and the intersection was calculated. DEGs were then put into String database to create a network of protein-protein interactions (PPI). Ten algorithms are used in the Cytohubba plugin to find the common hub genes. Three DI-AKI models' hub gene expression was verified in vivo and in vitro using PCR and western blot. To investigate the hub gene's potential as a biomarker, protein levels of mouse serum and urine were measured by ELISA kits. The UUO, IRI and aristolochic acid I-induced nephrotoxicity (AAN) datasets in the GEO database were utilized for external data verification by WGCNA and Limma package. Finally, the Elisa kit was used to identify DI-AKI patient samples. Results: 95 up-regulated common DEGs and 32 down-regulated common DEGs were obtained using Limma package. A PPI network with 84 nodes and 24 edges was built with confidence >0.4. Four hub genes were obtained by Algorithms of Cytohubba plugin, including TLR4, AOC3, IRF4 and TNFAIP6. Then, we discovered that the protein and mRNA levels of four hub genes were significantly changed in the DI-AKI model in vivo and in vitro. External data validation revealed that only the AAN model, which also belonged to DI-AKI model, had significant difference in these hub genes, whereas IRI and UUO did not. Finally, we found that plasma TLR4 levels were higher in patients with DI-AKI, especially in vancomycin-induced AKI. Conclusion: The immune system and inflammation are key factors in DI-AKI. We discovered the immunological and inflammatory-related genes TLR4, AOC3, IRF4, and TNFAIP6, which may be promising specific biomarkers and essential hub genes for the prevention and identification of DI-AKI.

Species richness patterns and the determinants of larch forests in China.

Larch forests are important for species diversity, as well as soil and water conservation in mountain regions. In this study, we determined large-scale patterns of species richness in larch forests and identified the factors that drive these patterns. We found that larch forest species richness was high in southern China and low in northern China, and that patterns of species richness along an elevational gradient depend on larch forest type. In addition, we found that patterns of species richness in larch forests are best explained by contemporary climatic factors. Specifically, mean annual temperature and annual potential evapotranspiration were the most important factors for species richness of tree and shrub layers, while mean temperature of the coldest quarter and anomaly of annual precipitation from the Last Glacial Maximum to the present were the most important for that of herb layer and the whole community. Community structural factors, especially stand density, are also associated with the species richness of larch forests. Our findings that species richness in China's larch forests is mainly affected by energy availability and cold conditions support the ambient energy hypothesis and the freezing tolerance hypothesis.

[Flora and geographic pattern of mountain forests at community level in Taihang Mountains: Results based on plant community survey]. / å¤ªè¡Œå±±å±±åœ°æ£®æž—ç¾¤è½æ¤ç‰©åŒºç³»ä¸Žåœ°ç†æ ¼å±€­­åŸºäºŽæ¤ç‰©ç¾¤è½æ¸ 查数据.

Taihang Mountains is located on the eastern edge of the second step of Chinese topography, which is the natural boundary between Loess Plateau and North China Plain and is considered as one of the important priority areas for biodiversity conservation in China. We took 108 counties involved in the generalized Taihang Mountains as the research area to systematically analyze the characteristics of family and genus characters, floristic composition, geographical pattern of plant diversity and species richness hotspots at community level of mountain forests in Taihang Mountains. A total of 963 species of seed plants belonging to 447 genera and 100 families were recorded in 778 forest plots in Taihang Mountains. Within all the species, 12 species of gymnosperms belonging to 7 genera of 3 families, 951 species of angiosperms belonging to 440 genera of 97 families. Herbaceous plants (71.1%) was the dominant life form. The distribution types of families were mainly tropical (38%) and temperate (24%), and the distribution types of genera were mainly temperate (68.7%). The horizontal distribution pattern of plant diversity showed a trend of increasing from southwest to northeast. Species richness was positively correlated with the latitude and longitude. However, the richness patterns of different life-form plants were different, in that herbaceous richness was positively correlated with the longitude and latitude but that of woody plants was not. In the vertical gradient, plant richness of Taihang Mountains presented a single-peak distribution, which was concentrated in the low and middle elevations of 400-1800 m and peaked at 1000-1200 m. Based on the community inventory data, we mapped plant richness of Taihang Mountain forest community. The mountain areas such as Xiaowutai Mountain, Yuntai Mountain, Taiyue Mountain, Wangwu Mountain and Zhongtiao Mountain were identified as hotspots of plant richness, which should be included in the key planning and management areas of the Taihang Mountains priority protection.

Range expansion and habitat shift triggered elevated diversification of the rice genus (Oryza, Poaceae) during the Pleistocene.

BACKGROUND: The rice genus (Oryza) contains many wild genetic resources that are vital to the well-being of humans. However, little is known about the process by which the genus diversified or the factors that drove its speciation. Here, we integrated the phylogenetic, molecular dating and biogeographic methods to investigate the spatial-temporal patterns of Oryza diversification, and used a series of model tests to examine whether intercontinental migrations and/or key innovations were associated with significant changes in diversification rates in the genus. RESULTS: Oryza became differentiated in tropical Asia in the Miocene. There were two migrations from the ancestral area into Africa and Australia during the Miocene. We inferred at least 10 migration events out of tropical Asia since the Pleistocene, mainly involving the species adapting open habitat. A rapid increase in diversification rates of the whole Oryza occurred during the Pleistocene. Intercontinental migrations from tropical Asia to other tropical regions were positively correlated with shift in habitat, but not with changes in life history. A habitat preference shift from shade tolerant to open habitat predated the burst in diversification rates. CONCLUSIONS: Rice species may have been pre-adapted to invade open habitat. Significant increase in diversification rates occurred during the Pleistocene and is associated with range expansion and habitat shift, but not with life history. The rice genus provides an excellent case supporting the idea that range expansion and invasion of novel habitats can drive the diversification of a group.