Puerarin specifically disrupts osteoclast activation via blocking integrin-ß3 Pyk2/Src/Cbl signaling pathway.

OBJECTIVE: Given the limitations of current anti-resorption agents for postmenopausal osteoporosis, there is a need for alternatives without impairing coupling crosstalk between bone resorption and bone formation ie. osteoclastogenesis. Puerarin, a unique C-glycoside isoflavonoid, was found to be able to prevent bone loss by inhibiting bone resorption, but the underlying mechanism was controversial. In this study, we investigated the effects of puerarin on osteoclastic differentiation, activation and bone resorption and its underlying molecular mechanism in vitro, and then evaluated the effects of puerarin on bone metabolism using an ovariectomized (OVX) rat model. METHODS: In vitro, the effect of puerarin on osteoclastic cytotoxicity, differentiation, apoptosis, activation and function were studied in raw 264.7 â€‹cells and mouse BMMs. Mechanistically, osteoclast-related makers were determined by RT-PCR, western blot, immunofluorescence, and kinase activity assay. In vivo, Micro-CT, histology, serum bone biomarker, and mechanical testing were used to evaluate the effects of puerarin on preventing osteoporosis. RESULTS: Puerarin significantly inhibited osteoclast activation and bone resorption, without affecting osteoclastogenesis or apoptosis. In terms of mechanism, the expressions of protein of integrin-ß3 and phosphorylations of Src, Pyk2 and Cbl were lower in puerarin group than those in the control group. Oral administration of puerarin prevented OVX-induced trabecular bone loss and significantly improved bone strength in rats. Moreover, puerarin significantly decreased trap positive osteoclast numbers and serum TRAP-5b, CTx1, without affecting bone formation rate. CONCLUSIONS: Collectively, puerarin prevented the bone loss in OVX rat through suppression of osteoclast activation and bone resorption, by inhibiting integrin-ß3-Pyk2/Cbl/Src signaling pathway, without affecting osteoclasts formation or apoptosis. TRANSLATIONAL POTENTIAL OF THIS ARTICLE: These results demonstrate the unique mechanism of puerarin on bone metabolism and provide a novel agent for prevention of postmenopausal osteoporosis.

Seasonal Succession of Bacterial Communities in Three Eutrophic Freshwater Lakes.

Urban freshwater lakes play an indispensable role in maintaining the urban environment and are suffering great threats of eutrophication. Until now, little has been known about the seasonal bacterial communities of the surface water of adjacent freshwater urban lakes. This study reported the bacterial communities of three adjacent freshwater lakes (i.e., Tangxun Lake, Yezhi Lake and Nan Lake) during the alternation of seasons. Nan Lake had the best water quality among the three lakes as reflected by the bacterial eutrophic index (BEI), bacterial indicator (Luteolibacter) and functional prediction analysis. It was found that Alphaproteobacteria had the lowest abundance in summer and the highest abundance in winter. Bacteroidetes had the lowest abundance in winter, while Planctomycetes had the highest abundance in summer. N/P ratio appeared to have some relationships with eutrophication. Tangxun Lake and Nan Lake with higher average N/P ratios (e.g., N/P = 20) tended to have a higher BEI in summer at a water temperature of 27 °C, while Yezhi Lake with a relatively lower average N/P ratio (e.g., N/P = 14) tended to have a higher BEI in spring and autumn at a water temperature of 9-20 °C. BEI and water temperature were identified as the key parameters in determining the bacterial communities of lake water. Phosphorus seemed to have slightly more impact on the bacterial communities than nitrogen. It is expected that this study will help to gain more knowledge on urban lake eutrophication.

Bacterial eutrophic index for potential water quality evaluation of a freshwater ecosystem.

Water quality evaluation of freshwater ecosystems has been widely reported based on the physical and chemical parameters of water (e.g., Carlson's trophic state index (TSI)), while the aquatic microorganisms are actually a more intuitive way to reflect the eutrophic levels. This article was based on 27 global freshwater ecosystems including freshwater rivers, lakes, and reservoirs. Bacterial eutrophic index (BEI) was determined as the function of temperature and abundances of Cyanobacteria and Actinobacteria. BEI and TSI values of the freshwater ecosystems were determined and the correlation analysis of TSI and BEI indicated their positive correlation (ρ = 0.452, p < 0.01). Furthermore, an eutrophication classification based on BEI was proposed. It turned out that BEI was a possible feasible method for water quality evaluation. The aquatic microorganism-based method such as BEI should be considered for water quality evaluation of a freshwater ecosystem. Complicated models combined with physicochemical (e.g., TSI) and microbial (e.g., BEI) method are recommended for water quality evaluation of a freshwater ecosystem in future.

Bacterial community and eutrophic index analysis of the East Lake.

This study investigated bacterial diversities in surface water and sediment of the East Lake located in Wuhan, China. Bacterial community of lake water was mainly composed of Proteobacteria (31.1%), Actinobacteria (25.0%), Bacteroidetes (18.6%), Cyanobacteria (18.9%), Planctomycetes (2.4%) and Verrucomicrobia (1.4%), while more abundant and richer bacterial community was found in the sediments, e.g. 46.1% for Proteobacteria, 10.1% for Bacteroidetes, 8.7% for Chloroflexi, 8.4% for Acidobacteria, 5.0% for Cyanobacteria, 3.6% for Firmicutes, 3.1% for Planctomycetes, 2.8% for Actinobacteria and 2.3% for Nitrospirae. The decreased bacterial community richness and abundance was found in poor-quality water. Moreover, Bacterial Eutrophic Index (BEI) was firstly put forward to quantitatively describe the water quality of a freshwater ecosystem, which was defined as the ratio of abundance of Cyanobacteria and Actinobacteria in water. It was demonstrated BEI was well correlated to Carlson's Trophic State Index (TSI) (Spearman's ρ = 0.848, p < 0.01). The average TSI and BEI were determined to be 64 and 0.81, suggesting that East Lake could be classified as a medium eutrophic level.

Bacterial communities of four adjacent fresh lakes at different trophic status.

Knowing the microbial compositions in fresh lakes is significant to explore the mechanisms of eutrophication and algal blooms. This study reported on the bacterial communities of the four adjacent fresh lakes at different trophic status by Illumina MiSeq Platform, which were Tangxun Lake (J1), Qingling Lake (J2), Huangjia Lake (J3) and Niushan Lake (J4) in Wuhan, China. J1 had the highest salinity and phosphorus. J2 was abundant in TC (Total Carbon)/TOC (Total Organic Carbon.), calcium and magnesium. J3 had the highest content of nitrogen, iron and pollution of heavy metals. High-throughput sequencing analysis of the 16S rRNA gene revealed that the eutrophic lakes (J1, J2 and J3) were dominated by Cyanobacteria (46.1% for J1, 40.8% for J2, 33.4% for J3) and the oligotrophic lake (J4) was dominated by Actinobacteria (34.2%). An increase of Cyanobacteria could inhibit the growth of Proteobacteria, Actinobacteria and Bacteroidetes. Functional inferences from 16S rRNA sequences suggested that J4 had more abundant bacteria with regard to substrate metabolism than J1, J2, and J3. Burkholderia and Fluviicola might be a suggestion of good water quality. The results demonstrated that the bacterial community could well reflect the water quality of the four lakes.