Protective mechanisms of Leontopodium leontopodioides extracts on lipopolysaccharide-induced acute kidney injury viathe NF-κB/NLRP3 pathway

Sepsis-induced uncontrolled systemic inflammatory response syndrome (SIRS) is a critical cause of multiple organ failure. Acute kidney injury (AKI) is one of the most serious complications associated with an extremely high mortality rate in SIRS, and it lacked simple, safe, and effective treatment strategies. Leontopodium leontopodioides (Willd.) Beauv (LLB) is commonly used in traditional Chinese medicine for the treatment of acute and chronic nephritis. However, it remains unclear whether lipopolysaccharide (LPS) affects LPS-induced AKI. To identify the molecular mechanisms of LLB in LPS-induced HK-2 cells and mice, LLB was prepared by extraction with 70% methanol, while a lipopolysaccharide (LPS)-induced HK-2 cell model and an AKI model were established in this study. Renal histopathology staining was performed to observe the morphology changes. The cell supernatant and kidney tissues were collected for determining the levels of inflammatory factors and protein expression by ELISA, immunofluorescence, and Western blot. The results indicated that LLB significantly reduced the expression of IL-6 and TNF-α in LPS-induced HK-2 cells, as well as the secretion of IL-6, TNF-α, and IL-1β in the supernatant. The same results were observed in LPS-induced AKI serum. Further studies revealed that LLB remarkably improved oxidative stress and apoptosis based on the content of MDA, SOD, and CAT in serum and TUNEL staining results. Notably, LLB significantly reduced the mortality due to LPS infection. Renal histopathology staining results supported these results. Furthermore, immunofluorescence and Western blot results confirmed that LLB significantly reduced the expression of the protein related to the NF-κB signaling pathway and NLRP3, ASC, and Caspase-1 which were significantly increased through LPS stimulation. These findings clearly demonstrated the potential use of LLB in the treatment of AKI and the crucial role of the NF-κB/NLRP3 pathway in the process through which LLB attenuates AKI induced by LPS.

[Characteristics of Leontopodium leontopodioides leaf stochiometry with altitude and their relationship with soil nutrients in Qilian Mountains, Northwest China]

Foliar stoichiometry provides information on the biotic and abiotic changes of environment. We examined the stoichiometric characteristics of plant leaves at different altitudes to understand how plants adapt to environmental changes. Foliar stoichiometry of Leontopodium leontopodioides at various altitudes (2400, 2600, 2800, 3000 and 3200 m) were analyzed in the Qilian Mountains of China. Across the altitude gradient, mean value of leaf carbon content (LC), nitrogen content (LN), and phosphorous content (LP) of L. leontopodioides was 401.27, 23.99 and 1.22 g·kg^-1, respectively. The mean value of LC:LN, LC:LP and LN:LP was 16.8, 352.5 and 20.7, respectively. LC, LC:LN, LC:LP and LN:LP initially increased with increases in altitude, rea-ching the maximum at 2600 m, then decreased, reaching the minimum at 3000 m, and finally increased again. LP exhibited the opposite trend. LN demonstrated an initial decrease with altitude, reaching the minimum at 2800 m, followed by an increase at higher altitudes. LC did not correlate with LN, but was significantly negatively correlated with LP. LN was significantly positively correlated with LP. There was no correlation between LN and any other stoichiometry ratios. LP showed a significantly negative correlation with other stoichiometry ratios. LC:LN, LC:LP, and LN:LP were positively correlated with each other. Both soil total nitrogen and total phosphorus affected LC and LN, whereas LP was significantly negatively correlated with soil total phosphorus. The results suggested that the growth of L. leontopodioides in the study region was mainly limited by P availability.

Elevational variations of leaf stochiometry in Leontopodium leontopodioides on the Qinghai-Tibetan Plateau, China

Topography has major impacts on the trade-off of plant survival strategies. Exploring the differential pattern of leaf ecological stoichiometry along the elevation gradient contributes to a better understanding of plant's response to environmental changes and its ecological adaptability. We investigated leaf C, N, and P concentrations and stoichiometric ratios of Leontopodium leontopodioides at three elevations, including from 4400 m to 4700 m, from 4701 m to 5000 m, and from 5001 m to 5300 m, on the northeastern margin of the Qinghai-Tibetan Plateau in China. The results showed that the concentrations of leaf C, N, and P of L. leontopodioides were 405.36 g·kg^-1, 18.42 g·kg^-1 and 0.94 g·kg^-1, respectively. Leaf C/N, C/P, and N/P were 22.67, 467.61 and 20.30, respectively. The concentrations of leaf N and P of L. leontopodioides consistently increased with the increases of elevation. The coefficient of variations for leaf C, N and P concentrations and ratios of L. leontopodioides were all less than 30%, with an order of P (30%) > C/P (29%) > C/N (18%) > N (17%) > N/P (15%) > C (3%). The growth of L. leontopodioides on the Qinghai-Tibetan Plateau was mainly limited by P availability.

and Leontopodium leontopodioides to CC chemokine receptor 2b (CCR2b)

The present study was designed to establish a suitable assay to explore CCR2b receptor antagonists from the natural products of Artemisia rupetris and Leontopodium leontopodioides. An aequorin assay was developed as a cell-based assay suitable for 384-well microplate and used for screening CCR2b receptor antagonists from natural products. Through establishing suitable conditions, the assay was shown to be suitable for screening of CCR2b receptor antagonists. Seven compounds were identified in preliminary screening. Five of them showed evident dose-response relationship in secondary screening. The structure-activity relationship study suggested that 7-position hydroxyl group of flavonoids was necessary, a polar group should be introduced on the 3-position, and the substituents on 2-position benzene ring of flavonoids have little influence on the potentency of the inhibition activity on CCR2b receptor. The ortho-position dihydroxyl structure in quinic acid compounds may be important. In conclusion, Compounds HR-1, 5, 7, and AR-20, 35 showed activity as antagonist of CCR2b receptor, which shed lights on the development of novel drugs as CCR2b receptor antagonists for preventing inflammation related diseases.