ATF6 aggravates apoptosis in early porcine embryonic development by regulating organelle homeostasis under high-temperature conditions

Activating transcription factor 6(ATF6),one of the three sensor proteins in the endoplasmic reticulum(ER),is an important regulator of ER stress-induced apoptosis.ATF6 resides in the ER and,upon activation,is translocated to the Golgi apparatus,where it is cleaved by site-1 protease(S1P)to generate an amino-terminal cytoplasmic fragment.Although recent studies have made progress in elucidating the regulatory mechanisms of ATF6,its function during early porcine embryonic development under high-temperature(HT)stress remains unclear.In this study,zygotes were divided into four groups:control,HT,HT+ATF6 knockdown,and HT+PF(S1P inhibitor).Results showed that HT exposure induced ER stress,which increased ATF6 protein expression and led to a decrease in the blastocyst rate.Next,ATF6 expression was knocked down in HT embryos under microinjection of ATF6 double-stranded RNA(dsRNA).Results revealed that ATF6 knockdown(ATF6-KD)attenuated the increased expression of CHOP,an ER stress marker,and Ca2+release induced by HT.In addition,ATF6-KD alleviated homeostasis dysregulation among organelles caused by HT-induced ER stress,and further reduced Golgi apparatus and mitochondrial dysfunction in HT embryos.AIFM2 is an important downstream effector of ATF6.Results showed that ATF6-KD reduced the occurrence of AIFM2-mediated embryonic apoptosis at HT.Taken together,our findings suggest that ATF6 is a crucial mediator of apoptosis during early porcine embryonic development,resulting from HT-induced ER stress and disruption of organelle homeostasis.

慢病毒载体对MDA-MB-231细胞中microRNA-18a-3P表达的影响

目的构建人microRNA-18a-3P(miR-18a-3P)过表达及干扰慢病毒载体,研究病毒感染人乳腺癌细胞系MDA-MB-231的步骤和方法。方法 PCR技术扩增相应目的基因片段并进行酶切,回收后与目的基因连接,产物转化细菌感受态细胞,对阳性克隆测序行对比分析,构建miR-18a-3P过表达及干扰慢病毒载体,荧光法测定病毒滴定;倒置荧光显微镜观察人乳腺癌细胞MDA-MB-231转染及筛选过程的转染效率,筛选最佳MOI值;qRT-PCR检测慢病毒转染后MDA-MB-231细胞内miR-18a-3P的表达。结果测序分析证实重组慢病毒构建正确;过表达及干扰慢病毒滴度分别为2×10~9和1×10~9 TU/ml;加Polybrene较未加Polybrene转染效率升高,当感染复数为10 TU/ml,Polybrene浓度为1μg/ml时,转染效率最佳;miR-18a-3P转染组过表达miR-18a-3P的相对表达量较空白对照组、阴性对照组高(P<0.05),miR-18a-3P转染组干扰表达miR-18a-3P的相对表达量较空白对照组、阴性对照组低(P<0.05)。结论成功构建了miR-18a-3P过表达及干扰慢病毒表达载体,对人乳腺癌细胞MDA-MB-231进行转染和筛选后,可快速高效率获得所需目的细胞。

Characterization of metal element distributions in the rat brain following ischemic stroke by synchrotron radiation microfluorescence analysis

Ischemic stroke is one of the leading causes of death worldwide,and effective treatment strategies in the chronic phase of this disease remain insufficient.Homeostasis of metals in the brain plays an important role in maintaining normal brain function.However,the dynamic spatial distributions of iron,zinc,calcium,potassium,and copper in a rat brain following ischemic stroke and the association between structural distribution and function remain to be elucidated.In this study,we used a synchrotron radiation-based micro-X-ray fluorescence technique to image element mapping changes in special rat brain regions after ischemic stroke,showing the distribution characteristics of iron,zinc,calcium,potassium,and copper.We demonstrated,for the first time,the consistent dynamic spatial distributions of metal elements at a series of time points(3 h,4.5 h,6 h,12 h,1 d,3 d,5 d,7 d,10 d,14 d,28 d)after brain ischemia,which revealed that the homeostasis of iron,zinc,calcium,potassium,and copper in the brain was disturbed with distinctive change trends,providing clear insights in understanding the underlying pathogenesis of stroke from a novel perspective,thus laying the foundation of further developing new drug targets for stroke treatment.

Realizing high thermoelectric performance of Cu and Ce co-doped p-type polycrystalline SnSe via inducing nanoprecipitation arrays

Thermoelectric(TE)performance of polycrystalline stannous selenide(SnSe)has been remarkably promoted by the strategies of energy band,defect engineering,etc.However,due to the intrinsic insufficiencies of phonon scattering and carrier concentration,it is hard to simultaneously realize the regulations of electrical and thermal transport properties by one simple approach.Herein,we develop Cu and Ce co-doping strategy that can not only greatly reduce lattice thermal conductivity but also improve the electrical transport properties.In this strategy,the incorporated Cu and Ce atoms could induce high-density SnSe_(2) nanoprecipitation arrays on the surface of SnSe microplate,and produce dopant atom point defects and dislocations in its interior,which form multi-scale phonon scattering synergy,thereby presenting an ultralow thermal conductivity of 0.275 W·m^(−1)·K^(−1) at 786 K.Meanwhile,density functional theory(DFT)calculations,carrier concentration,and mobility testing reveal that more extra hole carriers and lower conducting carrier scattering generate after Cu and Ce co-doping,thereby improving the electrical conductivity.The co-doped Sn_(0.98)Cu_(0.01)Ce_(0.01)Se bulk exhibits an excellent ZT value up to~1.2 at 786 K and a high average ZT value of 0.67 from 300 to 786 K.This work provides a simple and convenient strategy of enhancing the TE performance of polycrystalline SnSe.

Improving tribological and corrosion resistance of Ti6Al4V alloy by hybrid microarc oxidation/enameling treatments

A promising duplex coating was prepared by microarc oxidation（MAO） and enameling processes onto polished Ti6A14V alloy. The TiO2 ceramic coating deposited by MAO was characterized and then combined with an enameling treatment in order to improve the tribological and corrosion resistance of Ti6A14V alloy. The morphology, phase composition, and hardness of MAO and MAO/enameling-coated Ti6A14V alloy were evaluated by scanning electron microscopy（SEM）, X-ray diffraction（XRD）, and Vickers microhardness tester, respectively.The tribological performance was investigated using a ballon-disk tribometer. The corrosion resistance was studied using immersion tests and potentiodynamic polarization.Wear tests show that the enamel coating on the MAOcoated surface causes a reduction in the friction coefficient.Immersion tests demonstrate that the duplex coating is more effective in improving the corrosion resistance of Ti6A14V than the MAO coating especially at high temperature（80 ℃）. Potentiodynamic polarization curves reveal that the corrosion potential of the duplex coating increases by about 250 mV and the corrosion current density is slightly lower than that of the MAO coating. The duplex coating is superior to the stand-alone MAO coating in improving the tribological and corrosion behavior of Ti6A14V.

Proteome landscape and spatial map of mouse primordial germ cells

Primordial germ cells(PGCs)are precursors of both male and female gametes as fundamental materials for organism development.The transcriptome,methylome,and chromatin accessibility profiles of PGCs in both mice and humans have been recently reported.However,little is known about the characteristics of PGCs at the protein levels,which directly exert cellular functions.Here,we construct landscapes of both proteome and 3D spatial distribution of mouse PGCs at E11.5,E13.5 and E16.5 days,the three critical developmental windows for PGCs'sex differentiation,female meiosis initiation and male mitotic arrest.In each developmental stage of PGCs,nearly 2,000–3,000 proteins are identified,among which specific functional pathways such as oxidative phosphorylation,DNA damage repair,and meiotic cell cycle are involved for different events during PGCs development.Interestingly,by 3D modeling we find that PGCs spatially cluster into around 1,300 nests in genital ridge at E11.5 and the nest number is not increased by the exponential proliferation of PGCs.Comparative analysis of our proteomic data with published transcriptomic data does not show a close correlation,meaning that the practically executive factors are beyond the transcriptome.Thus,our work offers a valuable resource for the systematic investigations of PGC development at protein level and spatial map.