LIN28A inhibits DUSP family phosphatases and activates MAPK signaling pathway to maintain pluripotency in porcine induced pluripotent stem cells

LIN28A,an RNA-binding protein,plays an important role in porcine induced pluripotent stem cells(piPSCs).However,the molecular mechanism underlying the function of LIN28A in the maintenance of pluripotency in piPSCs remains unclear.Here,we explored the function of LIN28A in piPSCs based on its overexpression and knockdown.We performed total RNA sequencing(RNA-seq)of piPSCs and detected the expression levels of relevant genes by quantitative real-time polymerase chain reaction(qRT-PCR),western blot analysis,and immunofluorescence staining.Results indicated that piPSC proliferation ability decreased following LIN28A knockdown.Furthermore,when LIN28A expression in the shLIN28A2 group was lower(by 20%)than that in the negative control knockdown group(shNC),the pluripotency of piPSCs disappeared and they differentiated into neuroectoderm cells.Results also showed that LIN28A overexpression inhibited the expression of DUSP(dual-specificity phosphatases)family phosphatases and activated the mitogen-activated protein kinase(MAPK)signaling pathway.Thus,LIN28A appears to activate the MAPK signaling pathway to maintain the pluripotency and proliferation ability of piPSCs.Our study provides a new resource for exploring the functions of LIN28A in piPSCs.

Analysis of oxide layer structure in nitrided grain-oriented silicon steel

The production of low-temperature reheated grain-oriented silicon steel is mainly based on the acquired inhibitor method.Due to the additional nitriding process,a high nitrogen content exists in the oxide layer,which changes the structure of the oxide layer.In this study,the structure of the surface oxide layer after nitriding was analyzed by scanning electron microscopy(SEM),electron back-scattered diffraction(EBSD),glow discharge spectrometry(GDS),and X-ray diffraction(XRD).The size and orientation of ferritic grains in the oxide layer were characterized,and the distribution characteristics of the key elements along the thickness direction were determined.The results show that the oxide layer of the steel sample mainly comprised particles of Fe2SiO4 and spherical and lamellar SiO2,and Fe4N and fcc-Fe phases were also detected.Moreover,the size and orientation of ferritic grains in the oxide layer were different from those of coarse matrix ferritic grains beneath the oxide layer;however,some ferritic grains exhibited same orientations as those in the neighboring matrix.Higher nitrogen content was detected in the oxide layer than that in the matrix beneath the oxide layer.The form of nitrogen enrichment in the oxide layer was analyzed,and the growth mechanism of ferritic grains during the oxide layer formation is proposed.

OCT6 inhibits differentiation of porcine-induced pluripotent stem cells through MAPK and PI3K signaling regulation

As a transcription factor of the Pit-Oct-Unc(POU)domain family,octamer-binding transcription factor 6(OCT6)participates in various aspects of stem cell development and differentiation.At present,however,its role in porcine-induced pluripotent stem cells(piPSCs)remains unclear.Here,we explored the function of OCT6 in piPSCs.We found that piPSCs overexpressing OCT6 maintained colony morphology and pluripotency under differentiation conditions,with a similar gene expression pattern to that of non-differentiated piPSCs.Functional analysis revealed that OCT6 attenuated the adverse effects of extracellular signal-regulated kinase(ERK)signaling pathway inhibition on piPSC pluripotency by activating phosphatidylinositol 3-kinase-protein kinase B(PI3K-AKT)signaling activity.Our research sheds new light on the mechanism by which OCT6 promotes PSC maintenance.

Optimization of sgRNA expression strategy to generate multiplex gene-edited pigs

DEAR EDITOR,The use of CRISPR/Cas9 technology to breed polygenicmodified animals with desired traits holds great promise in agriculture and biomedicine. However, as most studies are based on human and mouse models, whether different single guide RNA(sg RNA) expression strategies affect multiplex gene-editing efficiency in domestic animals remains elusive.

Aerodynamic Performance Optmization and Data Mining of a Low Pressure Exhaust Hood

The design of exhaust hood is a typical high dimensional,expensive computational and black box problem.Multi-Point Search based Efficient Global Optimization(MSEGO)is proposed to solve this problem.MSEGO is used for the aerodynamic performance optimization of a low exhaust hood with non-axisymmetric outer flow guider.After optimization,the static pressure coefficient of the exhaust hood increases by 284.54%,and the aerodynamic performance analysis explains the reason of the improvement.Further,the analysis of variance(ANOVA)as the data mining technique is used to extract information of design space and analyze the influence of variables on the performance.Though aerodynamic performance analysis and data mining,it indicates that non-axisymmetric outer flow guider and the width of outer hood has a significant effect on the aerodynamic performance.Thereby,design lessons are derived and accumulated for the optimization of similar designs.

Meiotic transcriptional reprogramming mediated by cell-cell communications in humans and mice revealed by scATACseq and scRNA-seq

Meiosis is a highly complex process significantly influenced by transcriptional regulation.However,studies on the mechanisms that govern transcriptomic changes during meiosis,especially in prophase I,are limited.Here,we performed single-cell ATAC-seq of human testis tissues and observed reprogramming during the transition from zygotene to pachytene spermatocytes.This event,conserved in mice,involved the deactivation of genes associated with meiosis after reprogramming and the activation of those related to spermatogenesis before their functional onset.Furthermore,we identified 282 transcriptional regulators(TRs)that underwent activation or deactivation subsequent to this process.Evidence suggested that physical contact signals from Sertoli cells may regulate these TRs in spermatocytes,while secreted ENHO signals may alter metabolic patterns in these cells.Our results further indicated that defective transcriptional reprogramming may be associated with non-obstructive azoospermia(NOA).This study revealed the importance of both physical contact and secreted signals between Sertoli cells and germ cells in meiotic progression.

淀粉样前体蛋白通过抑制线粒体凋亡通路调节人肝癌细胞对5-氟尿嘧啶的抗性

目的:探讨淀粉样前体蛋白(APP)是否与肝癌细胞5-氟尿嘧啶(5-FU)耐药的过程相关,并探索其发挥作用的分子机制。创新点:首次探索并初步证实APP通过影响线粒体凋亡通路信号的传递可以促进肝癌5-FU耐药。方法:为探究肝癌中APP与5-FU耐药性之间的关系,我们构建了APP沉默和过表达的Bel7402细胞系,并进行了细胞活性检测、细胞凋亡和细胞周期、蛋白质印迹和荧光定量聚合酶链式反应(q PCR)等实验,验证过表达或沉默APP时,肝癌细胞的状态变化,以及APP发挥作用的分子机制。结论:与Bel7402细胞相比,耐药细胞Bel7402-5-FU中APP的表达明显上调。在Bel7402细胞中过表达APP降低了细胞的5-FU敏感性,而沉默Bel7402细胞的APP表达提升了细胞对5-FU的敏感性。从机制上讲,APP的过表达和沉默可以调节线粒体的凋亡途径和凋亡抑制基因(BAX、BID、Bcl-2和Bcl-xl)的表达,并进一步影响细胞凋亡的进程。综上所述,我们的结果初步表明APP在肝癌耐药过程中显著上调,APP能够通过影响线粒体凋亡通路调节肝癌细胞的5-FU敏感性,这为研究肝癌耐药机制提供了新的视角。

Mageb4,a Testis-Specific Gene,is Dispensable for Mouse Spermatogenesis

Objective:It has recently been shown that the melanoma antigen gene(MAGE)family is expressed in various tumor cell lines but silent in normal tissues,except germ cell lines.Mageb4,a member of the MAGE family,is highly expressed in the testis and homologous in humans and mice.Whole-exome sequencing studies have identifiedMageb4 as a possible X-linked cause of inherited male infertility.However,the function of Mageb4 protein remains largely unknown.Methods:Using clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein(Cas)9 technology,we generated aMageb4 knockout mouse model(Mageb4^-/Y)to explore the role of this gene in spermatogenesis.Results:First,immunostaining of testicular cells showed thatMageb4 is localized in the cytoplasm of spermatogonia.Second,Mageb4^-/Y male mice displayed significant increases in apoptosis.However,Mageb4^-/Y male mice showed normal fertility,including normal sperm concentration,sperm motility,and testicular and epididymal histology.Conclusions:These findings suggest that,despite testis-exclusive expression,Mageb4 is dispensable for mouse spermatogenesis.Future research should focus on the role of this gene in apoptosis,aiming to provide clinical guidance regarding male infertility.

Extracellular Vesicles in Mouse Testes Elevate the Level of Serum Testosterone

Objective:Testosterone plays an essential role in maintaining spermatogenesis and male fertility,and the primary known source of testosterone is testicular Leydig cells,which are regulated by luteinizing hormone(LH).However,whether any other ways of testosterone secretion exist still remains unknown.Methods:Transmission electron microscopy was used to detect testicular extracellular vesicles(EVs),which were isolated by an ultracentrifuge process.Separately,the concentrations of follicle-stimulating hormone(FSH),LH,and testosterone were measured by enzyme-linked immunosorbent assay.Results:Some EVs were found by tail vein injection to be present in mouse testes that elevate the circulating testosterone and LH levels in the blood,but do not affect FSH.Separately,they also promote testosterone production in the TM3 Leydig cell line in vitro.To determine whether the EVs from spermatogonia were involved in the secretion of testosterone,we used spermatogonial stem/progenitor cell line C18-4 cells and revealed that C18-4 cells promote production of testosterone in the TM3 Leydig cell line using the EVs.Conclusions:EVs in mouse testes likely originate from spermatogonia and involved in the regulation of the serum testosterone.Our results provide a new mechanism for the regulation of testosterone production.