Copper-Catalyzed Dual Remote Asymmetric Vinylogous Alkynylallylic Substitution of Yne-Allylic Esters with Coumarins.

Chiral coumarins and their derivatives are ubiquitous structural motifs found in an array of biologically and therapeutically active natural products and drugs. Herein, a highly enantioselective dual remote copper-catalyzed vinylogous alkynylallylic substitution of yne-allylic esters with coumarins has been developed. The practicality of this method is exemplified by the use of readily available starting materials; mild reaction conditions; excellent regio-, enantio-, and stereoselectivities; and the very broad substrate scope (67 examples), while the scalability and further applications of this method are illustrated by the gram-scale reaction and the series of derivations of the products.

Copper-Catalyzed Remote Asymmetric Yne-Allylic Substitution of Yne-Allylic Esters with Anthrones.

Anthrones are key structural motifs in many natural products and pharmaceutical chemicals. However, due to its unique tricyclic aromatic structure, the synthetic space for the development of chiral anthrone derivatives is largely limited. By utilizing the potential of the copper-catalyzed remote asymmetric yne-allylic substitution reaction, we describe the first example of copper-catalyzed highly regio- and enantioselective remote yne-allylic substitution on various yne-allylic esters with anthrones under a mild reaction condition, which afforded a range of enantioenriched 1,3-enynes with exhibiting broad functional group tolerance across 51 examples.

Hepatocyte-specific METTL3 ablation by Alb-iCre mice (GPT), but not by Alb-Cre mice (JAX), resulted in acute liver failure (ALF) and postnatal lethality.

Aim: In 2019, to examine the functions of METTL3 in liver and underlying mechanisms, we generated mice with hepatocyte-specific METTL3 homozygous knockout (METTL3Δhep) by simultaneously crossing METTL3fl/fl mice with Alb-iCre mice (GPT) or Alb-Cre mice (JAX), respectively. In this study, we explored the potential reasons why hepatocyte-specific METTL3 homozygous disruption by Alb-iCre mice (GPT), but not by Alb-Cre mice (JAX), resulted in acute liver failure (ALF) and then postnatal lethality.

Main Methods: Mice with hepatocyte-specific METTL3 knockout were generated by simultaneously crossing METTL3fl/fl mice with Alb-iCre mice (GPT; Strain No.

Copper-Catalyzed Remote Enantioselective Sulfonylation of Yne-Allylic Esters with Sodium Sulfinates.

Impressive progress has been made in the copper-catalyzed asymmetric propargylic substitution (APS) reaction, but its use in remote asymmetric yne-allylic substitution remains a challenging topic. Herein, we report the first remote enantioselective copper-catalyzed sulfonylation of yne-allylic esters with sodium sulfinates. The reaction is assumed to occur via a copper-vinylvinylidene species as the key reactive intermediate.

Hairy gene homolog increases nasopharyngeal carcinoma cell stemness by upregulating .

B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1) is overexpressed in various cancer types. We found that mRNA levels were elevated in nasopharyngeal carcinoma (NPC) cell lines. In immunohistochemical analyses, high Bmi-1 levels were observed in not only 5 of 38 non-cancerous nasopharyngeal squamous epithelial biopsies, but also in 66 of 98 NPC specimens (67.

mA demethylase ALKBH5 suppression contributes to esophageal squamous cell carcinoma progression.

Esophageal squamous cell carcinoma (ESCC) is a highly malignant gastrointestinal cancer with a high recurrence rate and poor prognosis. Although N-methyladenosine (mA), the most abundant epitranscriptomic modification of mRNAs, has been implicated in several cancers, little is known about its participation in ESCC progression. We found reduced expression of ALKBH5, an mA demethylase, in ESCC tissue specimens with a more pronounced effect in T3-T4, N1-N3, clinical stages III-IV, and histological grade III tumors, suggesting its involvement in advanced stages of ESCC.

Design and Synthesis of TY-Phos and Application in Palladium-Catalyzed Enantioselective Fluoroarylation of gem-Difluoroalkenes.

The first example of highly enantioselective fluoroarylation of gem-difluoroalkenes with aryl halides is presented by using a new chiral sulfinamide phosphine (Sadphos) type ligand TY-Phos. N-Me-TY-Phos can be easily synthesized on a gram scale from readily available starting materials in three steps. Salient features of this work including readily available starting materials, good yields, high enantioselectivities as well as broad substrate scope make this approach very practical and attractive.

Loss of PDK4 expression promotes proliferation, tumorigenicity, motility and invasion of hepatocellular carcinoma cells.

Although the roles and underlying mechanisms of other PDK family members (i.e., PDK1, PDK2 and PDK3) in tumor progression have been extensively investigated and are well understood, the functions and underlying molecular mechanisms of pyruvate dehydrogenase kinase 4 (PDK4) in the tumorigenesis and progression of various cancers [including hepatocellular carcinoma (HCC)] remain largely unknown.

miR-19 regulates the expression of interferon-induced genes and MHC class I genes in human cancer cells.

MicroRNA-19 (miR-19) is identified as the key oncogenic component of the miR-17-92 cluster. When we explored the functions of the dysregulated miR-19 in lung cancer, microarray-based data unexpectedly demonstrated that some immune and inflammatory response genes (i.e.

Optimization Strategy for Generating Gene-edited Tibet Minipigs by Synchronized Oestrus and Cytoplasmic Microinjection.

The Tibet minipig is a rare highland pig breed worldwide and has many applications in biomedical and agricultural research. However, Tibet minipigs are not like domesticated pigs in that their ovulation number is low, which is unfavourable for the collection of zygotes. Partly for this reason, few studies have reported the successful generation of genetically modified Tibet minipigs by zygote injection.

Loss of Cirbp expression is correlated with the malignant progression and poor prognosis in nasopharyngeal carcinoma.

The correlation of cold-inducible RNA-binding protein (Cirbp) expression with clinicopathological features including patient prognosis in nasopharyngeal carcinoma (NPC) was investigated. The expression of Cirbp in NPC cell lines and tissue specimens was examined by qRT-PCR or immunohistochemistry (IHC). Immunohistochemistry (IHC) results showed that high Cirbp expression was detected in 61 of 61 non-cancerous nasopharyngeal squamous epithelial biopsies, whereas the significantly reduced expression of Cirbp was observed in NPC specimens.

miR-26a promotes hepatocellular carcinoma invasion and metastasis by inhibiting PTEN and inhibits cell growth by repressing EZH2.

A previous study revealed that therapeutic miR-26a delivery suppresses tumorigenesis in a murine liver cancer model, whereas we found that forced miR-26a expression increased hepatocellular carcinoma (HCC) cell migration and invasion, which prompted us to characterize the causes and mechanisms underlying enhanced invasion due to ectopic miR-26a expression. Gain-of-function and loss-of-function experiments demonstrated that miR-26a promoted migration and invasion of BEL-7402 and HepG2 cells in vitro and positively modulated matrix metalloproteinase (MMP)-1, MMP-2, MMP-9, and MMP-10 expression. In addition, exogenous miR-26a expression significantly enhanced the metastatic ability of HepG2 cells in vivo.

TZAP plays an inhibitory role in the self-renewal of porcine mesenchymal stromal cells and is implicated the regulation of premature senescence via the p53 pathway.

Background: Mesenchymal stromal cells (MSCs) were originally characterized by the ability to differentiate into different mesenchymal lineages in vitro, and their immunomodulatory and trophic functions have recently aroused significant interest in the application of MSCs in cell-based regenerative medicine. However, a major problem in clinical practice is the replicative senescence of MSCs, which limits the cell proliferation potential of MSCs after large-scale expansion. Telomeric zinc finger-associated protein (TZAP), a novel specific telomere-binding protein, was recently found to stimulate telomere trimming and prevent excessive telomere elongation.

Chirality Transfer in Rhodium(I)-Catalyzed [3 + 2]-Cycloaddition of Vinyl Aziridines and Oxime Ethers: Atom-Economical Synthesis of Chiral Imidazolidines.

A highly efficient and stereoselective synthesis of enantioenriched imidazolidines by rhodium-catalyzed intermolecular [3 + 2] cycloaddition reaction of chiral vinyl aziridines and oxime ethers has been successfully developed. Notably, both aldoximes and ketoximes are suitable substrates to afford the corresponding chiral imidazolidines in high yields with good stereoselectivity. This transformation represents an unprecedented example that utilizes ketimine derivatives as an aza-[2C]-component in cycloadditions of vinyl aziridines.

Divergent Access to Functionalized Pyrrolidines and Pyrrolines via Iridium-Catalyzed Domino-Ring-Opening Cyclization of Vinyl Aziridines with β-Ketocarbonyls.

A useful synthesis of five-membered N-heterocycles has been developed through an iridium-catalyzed domino-ring-opening cyclization of vinylaziridines with β-ketocarbonyls. α-Substituted 1,3-dicarbonyls reacted with vinylaziridines to give 2-methylenepyrrolidines bearing two adjacent sp-carbon centers with moderate to excellent diastereoselectivity, while the reaction of α-unsubstituted 1,3-dicarbonyls afforded 2-pyrrolines in good yield.

Phosphine-catalyzed enantioselective [3 + 2] cycloadditions of γ-substituted allenoates with β-perfluoroalkyl enones.

The enantioselective construction of densely functionalized cyclopentene bearing contiguous three stereocenters has been a challenging task in organic synthesis. Herein, we present a phoshine-catalyzed highly regio-, diastereo- and enantioselective [3 + 2] cycloaddition of γ-substituted allenoates with β-perfluoroalkyl enones, delivering a wide range of densely functionalized perfluoroalkylated cyclopentenes with three contiguous chiral stereocenters.

Transfer of Chirality in the Rhodium-Catalyzed Chemoselective and Regioselective Allylic Alkylation of Hydroxyarenes with Vinyl Aziridines.

By taking advantage of chirality-transfer strategy, a chemo- and regioselective allylic alkylation of naphthols and phenols with vinylaziridines provides an atom-economic and efficient method for the synthesis of enantioenriched 2-vinyl-2-arylethylamine derivatives. Use of readily available starting materials, a broad substrate scope, high selectivity, mild reaction conditions, as well as versatile functionalizations of the aromatic ethylamine products make this approach very practical and attractive.

MiR-155 Enhances Insulin Sensitivity by Coordinated Regulation of Multiple Genes in Mice.

miR-155 plays critical roles in numerous physiological and pathological processes, however, its function in the regulation of blood glucose homeostasis and insulin sensitivity and underlying mechanisms remain unknown. Here, we reveal that miR-155 levels are downregulated in serum from type 2 diabetes (T2D) patients, suggesting that miR-155 might be involved in blood glucose control and diabetes. Gain-of-function and loss-of-function studies in mice demonstrate that miR-155 has no effects on the pancreatic β-cell proliferation and function.

Ectopic expression of Cripto-1 in transgenic mouse embryos causes hemorrhages, fatal cardiac defects and embryonic lethality.

Targeted disruption of Cripto-1 in mice caused embryonic lethality at E7.5, whereas we unexpectedly found that ectopic Cripto-1 expression in mouse embryos also led to embryonic lethality, which prompted us to characterize the causes and mechanisms underlying embryonic death due to ectopic Cripto-1 expression. RCLG/EIIa-Cre embryos displayed complex phenotypes between embryonic day 14.

R/L, a double reporter mouse line that expresses luciferase gene upon Cre-mediated excision, followed by inactivation of mRFP expression.

The Cre/loxP system has become an important tool for the conditional gene knockout and conditional gene expression in genetically engineered mice. The applications of this system depend on transgenic reporter mouse lines that provide Cre recombinase activity with a defined cell type-, tissue-, or developmental stage-specificity. To develop a sensitive assay for monitoring Cre-mediated DNA excisions in mice, we generated Cre-mediated excision reporter mice, designated R/L mice (R/L: mRFP(monomeric red fluorescent protein)/luciferase), express mRFP throughout embryonic development and adult stages, while Cre-mediated excision deletes a loxP-flanked mRFP reporter gene and STOP sequence, thereby activating the expression of the second reporter gene luciferase, as assayed by in vivo and ex vivo bioluminescence imaging.

Regiodivergent Intermolecular [3+2] Cycloadditions of Vinyl Aziridines and Allenes: Stereospecific Synthesis of Chiral Pyrrolidines.

The first rhodium-catalyzed intermolecular [3+2] cycloaddition reaction of vinyl aziridines and allenes for the synthesis of enantioenriched functionalized pyrrolidines was realized. [3+2] cycloaddition with the proximal C=C bond of N-allenamides gave 3-methylene-pyrrolidines in high regio- and diastereoselectivity, whereas, 2-methylene-pyrrolidines were obtained as the major products by the cycloadditions of vinyl aziridines with the distal C=C bond of allenes. Use of readily available starting materials, a broad substrate scope, high selectivity, mild reaction conditions, as well as versatile functionalization of the cycloadducts make this approach very practical and attractive.

Targeted Disruption of miR-17-92 Impairs Mouse Spermatogenesis by Activating mTOR Signaling Pathway.

The miR-17-92 cluster and its 6 different mature microRNAs, including miR-17, miR-18a, miR-19a, miR-20a, miR-19b-1, and miR-92a, play important roles in embryo development, immune system, kidney and heart development, adipose differentiation, aging, and tumorigenicity. Currently, increasing evidence indicates that some members of miR-17-92 cluster may be critical players in spermatogenesis, including miR-17, miR-18a, and miR-20a. However, the roles and underlying mechanisms of miR-17-92 in spermatogenesis remain largely unknown.