Cold-activated brown fat-derived extracellular vesicle-miR-378a-3p stimulates hepatic gluconeogenesis in male mice.

During cold exposure, activated brown adipose tissue (BAT) takes up a large amount of circulating glucose to fuel non-shivering thermogenesis and defend against hypothermia. However, little is known about the endocrine function of BAT controlling glucose homoeostasis under this thermoregulatory challenge. Here, we show that in male mice, activated BAT-derived extracellular vesicles (BDEVs) reprogram systemic glucose metabolism by promoting hepatic gluconeogenesis during cold stress. Cold exposure facilitates the selective packaging of miR-378a-3p-one of the BAT-enriched miRNAs-into EVs and delivery into the liver. BAT-derived miR-378a-3p enhances gluconeogenesis by targeting p110α. miR-378 KO mice display reduced hepatic gluconeogenesis during cold exposure, while restoration of miR-378a-3p in iBAT induces the expression of gluconeogenic genes in the liver. These findings provide a mechanistic understanding of BDEV-miRNA as stress-induced batokine to coordinate systemic glucose homoeostasis. This miR-378a-3p-mediated interorgan communication highlights a novel endocrine function of BAT in preventing hypoglycemia during cold stress.

Vertically integrated spiking cone photoreceptor arrays for color perception.

The cone photoreceptors in our eyes selectively transduce the natural light into spiking representations, which endows the brain with high energy-efficiency color vision. However, the cone-like device with color-selectivity and spike-encoding capability remains challenging. Here, we propose a metal oxide-based vertically integrated spiking cone photoreceptor array, which can directly transduce persistent lights into spike trains at a certain rate according to the input wavelengths. Such spiking cone photoreceptors have an ultralow power consumption of less than 400 picowatts per spike in visible light, which is very close to biological cones. In this work, lights with three wavelengths were exploited as pseudo-three-primary colors to form 'colorful' images for recognition tasks, and the device with the ability to discriminate mixed colors shows better accuracy. Our results would enable hardware spiking neural networks with biologically plausible visual perception and provide great potential for the development of dynamic vision sensors.

Formation and Stability of Bulk Nanobubbles in Different Solutions.

The existence of bulk nanobubbles is still controversial in spite of their significance in a large range of applications. Here, we developed a new method of compression-decompression to produce controllably bulk nanobubbles. Then, we further investigated the generation of bulk nanobubbles in pure water, acid, alkaline, and salt solutions using nanoparticle tracking analysis. The results indicated that the concentration of bulk nanobubbles depends on the decompression time and would reach a maximum value when the decompression time is about 30 min for the pure water system. More importantly, we gave a relatively direct evidence of the existence of bulk nanobubbles by measuring the X-ray fluorescence intensity of Kr in acid, alkaline, and salt solutions. It is shown that the decrease tendency in intensity of Kr in alkaline solution is similar to that in the concentration of bulk nanobubbles with the deposited time, indicating that the bulk nanobubbles produced indeed have gas inside. Furthermore, the concentration and stability of bulk nanobubbles in an alkaline solution are greatest compared with other two solutions regardless of gas types. The concentration of bulk nanobubbles will decrease in the order alkaline > acid/pure water > salt solutions. We believe that our results should be very helpful in understanding the formation and stability of bulk nanobubbles in different solutions.

The Role of Nanobubbles in the Precipitation and Recovery of Organic-Phosphine-Containing Beneficiation Wastewater.

Dissolved air flotation (DAF) is broadly applied in wastewater treatment, especially for the recovery of organic pollution with low concentration. However, the mechanism of interaction between nanoscale gas bubbles and nanoparticles in the process of DAF remains unclear. Here, we investigated the role of nanobubbles in the precipitation of styryl phosphoric acid (SPA)-Pb particles and recovering organic phosphine containined in beneficiation wastewater by UV-vis (ultraviolet-visible) spectra, microflotation tests, nanoparticle tracking analysis, dynamic light scattering, and atomic force microscopy measurements. As suggested from the results, nanobubbles can inhibit the crystallization of SPA-Pb precipitation, which makes the sediment flotation recovery below 20%. After the precipitation crystallization is completed, nanobubbles can flocculate precipitated particles, which can promote the flotation recovery of precipitated particles to 90%. On the basis of the results, we proposed a model to explain the different roles of nanobubbles in the process of precipitation and flotation of SPA-Pb particles. This study will be helpful to understand the interaction between nanobubbles and nanoparticles in the application of flotation.

MiR-23a modulates X-linked inhibitor of apoptosis-mediated autophagy in human luminal breast cancer cell lines.

Autophagy is a conserved multi-step lysosomal process that is induced by diverse stimuli including cellular nutrient deficiency. X-linked inhibitor of apoptosis (XIAP) promotes cell survival and recently has been demonstrated to suppress autophagy. Herein, we examined regulation of XIAP-mediated autophagy in breast cancer cells and determined the underlying molecular mechanism. To investigate this process, autophagy of breast cancer cells was induced by Earle's balanced salt solution (EBSS). We observed discordant expression of XIAP mRNA and protein in the autophagic process induced by EBSS, suggesting XIAP may be regulated at a post-transcriptional level. By scanning several miRNAs potentially targeting XIAP, we observed that forced expression of miR-23a significantly decreased the expression of XIAP and promoted autophagy, wherever down-regulation of miR-23a increased XIAPexpression and suppressed autophagy in breast cancer cells. XIAP was confirmed as a direct target of miR-23a by reporter assay utilizing the 3'UTR of XIAP. In vitro, forced expression of miR-23a promoted autophagy, colony formation, migration and invasion of breast cancer cell by down-regulation of XIAP expression. However, miR-23a inhibited apoptosis of breast cancer cells independent of XIAP. Xenograft models confirmed the effect of miR-23a on expression of XIAP and LC3 and that miR-23a promoted breast cancer cell invasiveness. Therefore, our study demonstrates that miR-23a modulates XIAP-mediated autophagy and promotes survival and migration in breast cancer cells and hence provides important new insights into the understanding of the development and progression of breast cancer.