Up-regulation of miR-126 via DNA methylation in hypoxia-preconditioned endothelial cells may contribute to hypoxic tolerance of neuronal cells.

BACKGROUND: Endothelial cells (ECs) can confer neuroprotection by secreting molecules. This study aimed to investigate whether DNA methylation contributes to the neuroprotective gene expression induced by hypoxia preconditioning (HPC) in ECs and to clarify that the secretion of molecules from HPC ECs may be one of the molecular mechanisms of neuroprotection. METHODS: Human microvascular endothelial cell-1 (HMEC-1) was cultured under normal conditions (C), hypoxia(H), and hypoxia preconditioning (HPC), followed by the isolation of culture medium (CM). SY5Y cell incubated with the isolated CM from HMEC-1 was exposed to oxygen-glucose deprivation (OGD). The DNA methyltransferases (DNMTs), global methylation level, miR-126 and its promotor DNA methylation level in HMEC-1 were measured. The cell viability and cell injury in SY5Y were detected. RESULTS: HPC decreased DNMTs level and global methylation level as well as increased miR-126 expression in HMEC-1. CM from HPC treated HMEC-1 also relieved SY5Y cell damage, while CM from HMEC-1 which over-expression of miR-126 can reduce injury in SY5Y under OGD condition. CONCLUSIONS: These findings indicate EC may secrete molecules, such as miR-126, to execute neuroprotection induced by HPC through regulating the expression of DNMTs.

Analysis of Atmospheric CO2 and CO at Akedala Atmospheric Background Observation Station, a Regional Station in Northwestern China.

Air samples were collected by flasks and analyzed via a Picarro G2401 gas analyzer for carbon dioxide (CO2) and carbon monoxide (CO) at the Akedala Atmospheric Background Station in Xinjiang, China, from September 2009 to December 2019, to analyze the changes in the characteristics of atmospheric CO2 and CO and determine the sources. The results show that the annual average CO2 concentration showed an increasing trend (growth rate: 1.90 ppm year-1), ranging from 389.80 to 410.43 ppm, and the annual average CO concentration also showed an increasing trend (growth rate: 1.78 ppb year-1), ranging from 136.30 to 189.82 ppb. The CO2 concentration and growth rate were the highest in winter, followed by autumn, spring, and summer. The CO concentration and growth rate were also the highest in winter due to anthropogenic emissions, ecosystem effects, and diffusion conditions. The main trajectories of CO2 and CO determined by the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model were parallel to the Irtysh River valley and then passed through the Old Wind Pass. Furthermore, the main source regions of CO2 and CO at the Akedala Station were eastern Kazakhstan, southern Russia, western Mongolia, and the Xinjiang Tianshan North Slope Economic Zone of China. This study reflects the characteristics of long-term changes in CO2 and CO concentrations at the Akedala station and provides fundamental data for the studies on environmental changes and climate change in Central Asia.

Novel Paclitaxel-Loaded Nanoparticles Based on Human H Chain Ferritin for Tumor-Targeted Delivery.

Paclitaxel (PTX), an excellent chemotherapeutic antitumor drug, is widely used to treat patients with various cancers. However, its clinical applications are greatly restricted by poor solubility and lack of targeting. Herein, we applied natural human H chain ferritin (HFtn) nanocages that can bind to tumor cells via interacting with the human transferritin receptor 1 (TfR1) leading to its endocytosis as the PTX carrier for the targeted delivery. PTX molecules were encapsulated into HFtn cavity using disassembly/reassembly method through adjusting pH. According to the requirements of drugs suitable for clinical trials, HFtn can be easily purified in high yields with no ligand modification or property modulation. We demonstrated that PTX molecules were successfully encapsulated in the protein nanocages. The HFtn-PTX nanoparticles exhibited similar morphology and structural characteristics to the hollow cage and showed significant cytotoxicity in vitro than the naked PTX. Flow cytometry, confocal laser scanning microscopy, and in vivo imaging of MDA-MB-231 tumor demonstrated the HFtn-PTX nanoparticles targeting ability to tumor cells. Cell apoptosis assay showed that HFtn-PTX had similar apoptotic characteristics on MDA-MB-231 cells as that of the free PTX. HFtn-PTX nanoparticles have higher in vivo therapeutic efficacy and lower systemic toxicity. The BALB/c mice model also confirmed the effectiveness of the nanoparticles. Specifically targeting to tumors and solving the solubility issue of water-insoluble drugs thus alleviating the side effects, HFtn can be an efficient hydrophobic drug delivery nanocarrier for further applications in cancer therapy.

CdTe quantum dot-based fluorescent probes for selective detection of Hg (II): The effect of particle size.

Mercury ions-induced fluorescence quenching properties of CdTe quantum dots (QDs) have been studied using the fluorescence spectroscopic techniques. By using the hydrothermal method, the CdTe QDs with different particles sizes from 1.98 to 3.68nm have been prepared, and the corresponding fluorescence emission wavelength is changed from 518 to 620nm. The fluorescence of QDs is enhanced after linking Bovine serum albumin (BSA) onto the surface of the QDs. Experimental results show that the fluorescence intensity of BSA-coated CdTe QDs could be effectively quenched when Hg2+ react with BSA-coated CdTe QDs. Interestingly, both the sensing sensitivity and selectivity of this fluorescence probe could be improved when the particle size of the QDs decreases. Thus the BSA-coated CdTe QDs with green fluorescence emission have better advantages than the BSA-coated CdTe QDs with red fluorescence for Hg2+ detection. Interference experiment results indicate that the influence from other metal ions could be neglected in the detection, and the Hg2+ could be specifically detected. By using this BSA-coated CdTe QDs-based fluorescence probe, the Hg2+ could be detected with an ultra-low detection limit of nanomole level, and the linear range spans a scope from 0.001 to 1µmol/L.

Genetic variability of PRNP in Chinese indigenous goats.

Polymorphism of the prion protein gene (PRNP) is usually associated with scrapie susceptibility or resistance. To determine the variability of PRNP in Chinese indigenous goat breeds, we isolated genomic DNA from goat blood and amplified and sequenced the coding region of the gene. We identified 10 polymorphic sites that gave rise to 28 haplotypes. Clear frequency differences were found between northern and southern breeds and confirmed by genetic distance analysis, except for the Tangshan dairy goat. Phylogeographic analysis supported the idea that northern and southern breeds might be considered separate clusters, except for the Tangshan dairy goat. The finding of significant differences in allele distribution in northern and southern goats, especially if involved in modulating resistance/susceptibility, needs to be carefully considered for the feasibility of selection plans for resistance to scrapie.