Publications by authors named "Junjie Gu"

52 Publications

An effective method for size-controlled gold nanoparticles synthesis with nonthermal microplasma.

Nanotechnology 2021 Jul 7;32(39). Epub 2021 Jul 7.

School of Control Engineering, Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement Technology, Northeastern University at Qinhuangdao, Qinhuangdao, People's Republic of China.

A simple, effective and interesting method for gold nanoparticles (AuNPs) synthesis with nonthermal microplasma is developed in this study. The device of dielectric barrier discharge (DBD) microplasma generator with a spray portion is designed and fabricated for uniform AuNPs synthesis. The AuNPs can be synthesized effectivelyby the DBD microplasma generated on the nozzle of the pneumatic micro-nebulizer. The mechanism of the AuNPs formation under microplasma, the effect of nebulization for uniform AuNPs synthesis and other significant parameters are investigated in the experiment. The morphology and optical properties of the synthesized gold nanoparticles are also characterized. The minimum particle size in average obtained by the proposed method is 4.9 ± 1.1 nm. The particle size of AuNPs can be controlled in the range of 4.9-16.8 nm by the various aqueous solution conditions.
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http://dx.doi.org/10.1088/1361-6528/ac0d80DOI Listing
July 2021

FMS-Related Tyrosine Kinase 3 Ligand Promotes Radioresistance in Esophageal Squamous Cell Carcinoma.

Front Pharmacol 2021 10;12:659735. Epub 2021 May 10.

Department of Radiotherapy, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.

The FMS-related tyrosine kinase 3 ligand (FL) has an important role in regulating FMS-related tyrosine kinase 3 (Flt-3) activity. Serum FL levels are markedly increased among patients with hematopoietic disease. However, its role in radiation treatment remains unclear. In this study, we investigated the effects of FL on radiotherapy for esophageal squamous cell carcinoma (ESCC). KYSE150 and KYSE450 cells were stimulated with FL (200 ng/ml). mRNA expression was analyzed using qRT-PCR. Cell viability was checked using CCK-8 assay kits. Proliferation was determined using the EdU assay. Radiosensitivity was detected through a colony-forming assay. Flow cytometry was used to evaluate cell apoptosis. The number of γH2AX foci was verified using an immunofluorescence assay. The change in relative proteins was determined by western blot analysis. The growth of transplanted tumors was demonstrated in nude mice. Our results showed that FL increased the radiation resistance of ESCC cells by promoting clone formation, increasing EdU incorporation, enhancing DNA damage repair, and inhibiting apoptosis. Moreover, the Flt-3 receptor expression significantly increased in ESCC cells after radiation, which may have been an important factor in their radioresistance. Our results suggest that FL increases the radioresistance of esophageal cancer cells and that FL-Flt-3 could be a potential target for enhancing radiosensitivity in ESCC.
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http://dx.doi.org/10.3389/fphar.2021.659735DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8141745PMC
May 2021

The role of PKM2 nuclear translocation in the constant activation of the NF-κB signaling pathway in cancer-associated fibroblasts.

Cell Death Dis 2021 03 17;12(4):291. Epub 2021 Mar 17.

Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Peking Union Medical College Hospital, Center of Excellence in Tissue Engineering Chinese Academy of Medical Sciences, Beijing Key Laboratory (No. BZO381), 100005, Beijing, China.

Cancer-associated fibroblasts (CAFs) play critical roles in cancer progression by regulating tumor cell proliferation, angiogenesis, and metastasis. Recent studies demonstrated that CAFs induce inhibitory immune cell infiltration and chemotherapy resistance in gastric cancer by activating the NF-κB signaling pathway to secrete IL6, IL8, and other inflammatory factors. Inhibition of the NF-κB signaling pathway in CAFs might be a potential therapeutic strategy in gastric cancer. However, how the NF-κB pathway is activated in CAFs remains unclear. We showed that mesenchymal stem cells (MSCs) differentiated into CAFs, induced by the exosomes derived from gastric cancer cells. During the process of differentiation from MSCs into CAFs, we showed that nuclear PKM2 expression was continuously upregulated and associated with NF-κB P65 acetylation, contributing to P65 nuclear retention in CAFs and constant transcription of IL-6, IL-8, and other inflammatory factors, thus promoting gastric cancer cell proliferation. We showed that NF-κB P65 acetylation was induced by P300. We showed that nuclear PKM2 was derived from exosomes of gastric cancer cell lines and the positive feedback loop induced by PKM2-P65 combination. It is also proved that P300 inhibitors can inhibit tumor proliferation in an AGS subcutaneous xenograft tumor model. Our study showed that gastric cancer cells influence the continuous activation of the NF-κB signaling pathway in CAFs by secreting gastric cancer exosomes containing PKM2, thus inducing abnormal metabolism and inflammation activation. This study provides a new therapeutic target for CAF normalization or deactivation strategies.
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http://dx.doi.org/10.1038/s41419-021-03579-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7969736PMC
March 2021

Hypoxic tumour cell-derived exosomal miR-340-5p promotes radioresistance of oesophageal squamous cell carcinoma via KLF10.

J Exp Clin Cancer Res 2021 Jan 23;40(1):38. Epub 2021 Jan 23.

Department of Radiation Oncology, The First Affiliated Hospital of Nanjing Medical University, No.300 Guangzhou Road, Nanjing, 210029, China.

Background: Radiotherapy resistance is a major obstacle in the treatment of oesophageal squamous cell carcinoma (OSCC). Hypoxia is a critical cause of radioresistance. However, the communication between hypoxic cells and aerobic cells via exosomes during the transfer of radiation resistance remains unclear.

Methods: Exo-miR-340-5p levels were analysed by RNA-seq and qRT-PCR. We co-cultured OSCC cells with isolated normoxic and hypoxic exosomes to study their impact on radiosensitivity. We used a specific exo-miR-340-5p mimic and knock-down retrovirus to explore the role of this miRNA in the transfer of radioresistance from hypoxic to normoxic cells. Dual-luciferase reporter and RIP assays were used to verify KLF10 as a putative target of miR-340-5p. Several in vitro assays were conducted and xenograft models were established to investigate the effect of exo-miR-340-5p on OSCC radiosensitivity. The plasma exo-miR-340-5p levels in OSCC patients were analysed to study the clinical value of this parameter.

Results: Hypoxic exosomes alleviated radiation-induced apoptosis and accelerated DNA damage repair. miR-340-5p was highly expressed in hypoxic exosomes and was transferred into normoxic cells, where it induced radioresistance. Overexpression of miR-340-5p in normoxic OSCC cells mimicked the radioresistance of cells co-cultured with hypoxic exosomes. Knockdown of miR-340-5p in hypoxic exosomes reversed the radioresistance effect, indicating that exo-miR-340-5p is critical for hypoxic EV-transferred radioresistance. KLF10 was identified as the direct target of miR-340-5p. Moreover, metformin was found to increase the expression of KLF10 and enhance the radiosensitivity of OSCC. Higher levels of miR-340-5p in the plasma exosomes from OSCC patients are related to a poorer radiotherapy response and prognosis.

Conclusions: Hypoxic tumour cell-derived exosomal miR-340-5p confers radioresistance in OSCC by targeting KLF10/UVRAG, suggesting that miR-340-5p could be a potential biomarker and therapeutic target for the enhancement of radiosensitivity in OSCC. Metformin can increase KLF10 expression, which ameliorates the radioresistance induced by exo-miR-340-5p transfer. Therefore, metformin could be further investigated as a therapeutic option for the treatment of OSCC.
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http://dx.doi.org/10.1186/s13046-021-01834-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7825246PMC
January 2021

Calcineurin A gamma and NFATc3/SRPX2 axis contribute to human embryonic stem cell differentiation.

J Cell Physiol 2021 Aug 3;236(8):5698-5714. Epub 2021 Jan 3.

CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, CAS Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.

Our understanding of signaling pathways regulating the cell fate of human embryonic stem cells (hESCs) is limited. Calcineurin-NFAT signaling is associated with a wide range of biological processes and diseases. However, its role in controlling hESC fate remains unclear. Here, we report that calcineurin A gamma and the NFATc3/SRPX2 axis control the expression of lineage and epithelial-mesenchymal transition (EMT) markers in hESCs. Knockdown of PPP3CC, the gene encoding calcineurin A gamma, or NFATC3, downregulates certain markers both at the self-renewal state and during differentiation of hESCs. Furthermore, NFATc3 interacts with c-JUN and regulates the expression of SRPX2, the gene encoding a secreted glycoprotein known as a ligand of uPAR. We show that SRPX2 is a downstream target of NFATc3. Both SRPX2 and uPAR participate in controlling expression of lineage and EMT markers. Importantly, SRPX2 knockdown diminishes the upregulation of multiple lineage and EMT markers induced by co-overexpression of NFATc3 and c-JUN in hESCs. Together, this study uncovers a previously unknown role of calcineurin A gamma and the NFATc3/SRPX2 axis in modulating the fate determination of hESCs.
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http://dx.doi.org/10.1002/jcp.30255DOI Listing
August 2021

The ATPase subunit of ATP6V1C1 inhibits autophagy and enhances radiotherapy resistance in esophageal squamous cell carcinoma.

Gene 2021 Feb 22;768:145261. Epub 2020 Oct 22.

Department of Radiation Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China. Electronic address:

Radiotherapy is one of the primary therapeutic modalities for patients diagnosed esophageal squamous cell carcinoma(ESCC). Previous studies have shown that chemotherapy resistance could be linked with the overexpression vascular ATPases(V-ATPase) subunits genes. However, it is unknown whether V-ATPase subunits genes play a role in radiotherapy resistance. The aim of this study was to investigate the effect of the ATP6V1C1 in radiotherapy resistance. siRNA and plasmids were used to transfect low expression of ATP6V1C1 in TE13 (human ESCC cell) and high expressed in ECA109 (human ESCC cell), respectively. To observe proliferation, radiosensitivity, apoptosis and DNA-damage response, colony formation assays, EDU assays, flow cytometry and γH2AX assay were used with or without radiation exposure, separately. The quantities of the autophagosomes and autolysosomes by immunofluorescence were calculated. Autophagic microstructure were discovered by transmission electron microscopy, and the study also repeated in vivo by nude mice. Western blot assay was applied to prove changes in relative proteins. We found that suppressing ATP6V1C1 increased the sensitivity of ESCC cells after RT. Silencing ATP6V1C1 with IR suppressed the tumor growth and promoted autophagy. Besides, the underlying mechanism of ATP6V1C1, which is not fatally disrupted, is that ATP6V1C1 with ionizing radiation (IR)decreased apoptosis and inhibited autophagy may by activating mTOR signaling to suppress radiosensitivity for ESCC cells. Thus, we first reported that the ATP6V1C1 may represent a potential radiotherapeutic target by effect on radiation sensitivity for ESCC.
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http://dx.doi.org/10.1016/j.gene.2020.145261DOI Listing
February 2021

Twenty-hydroxyecdysone produced by dephosphorylation and ecdysteroidogenesis regulates early embryonic development in the silkmoth, Bombyx mori.

Insect Biochem Mol Biol 2020 12 20;127:103491. Epub 2020 Oct 20.

Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8562, Japan. Electronic address:

Ecdysteroids are key regulators of embryonic development as well as molting and metamorphosis in insects. Although an active form of ecdysteroids, 20-hydroxyecdysone (20E) is known to be produced through ecdysteroidogenesis from cholesterol and dephosphorylation of 20E-phosphate during embryogenesis in Lepidoptera, the importance of these production mechanisms in embryonic development has been unclear. Here, we investigated the activation timing of ecdysteroidogenesis from cholesterol and 20E-phosphate dephosphorylation during early embryogenesis in non-diapause eggs of the silkmoth Bombyx mori by observing morphological development, quantifying 20E and 20E-phosphate, measuring transcripts of enzymes involved in 20E production, and detecting activity of these enzymes using egg extracts. Stage-dependent 20E fluctuation and changes in mRNA amounts of enzymes suggest that the two 20E-producing mechanisms are activated at different stages during embryogenesis. Furthermore, knockdown of a dephosphorylation enzyme delayed development at early embryogenesis, whereas knockdown of an ecdysteroidogenic enzyme delayed development at early-middle embryogenesis. These results suggest that 20E is primarily produced initially by dephosphorylation of 20E-phosphate, and then by ecdysteroidogenesis from cholesterol to induce progression of embryonic development in B. mori.
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http://dx.doi.org/10.1016/j.ibmb.2020.103491DOI Listing
December 2020

Focal adhesion kinase: Insight into its roles and therapeutic potential in oesophageal cancer.

Cancer Lett 2021 01 8;496:93-103. Epub 2020 Oct 8.

Department of Radiation Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu province, China. Electronic address:

Oesophageal cancer is associated with high morbidity and mortality rates because it is highly invasive and prone to recurrence and metastasis, with a five-year survival rate of <20%. Therefore, there is an urgent need for new methods aimed at improving therapeutic intervention. Several studies have shown that targeted therapy may be effective for the treatment of oesophageal cancer. Focal adhesion kinase (FAK), a non-receptor tyrosine kinase with kinase activity and scaffolding function, could be overexpressed in a variety of solid tumours, including oesophageal cancer. FAK participates in survival, proliferation, progression, adhesion, invasion, migration, epithelial-to-mesenchymal transition, angiogenesis, DNA damage repair, and other biological processes through multiple signalling pathways in cancer cells. It plays an important role in the occurrence and development of tumours and has been linked to the prognosis of oesophageal cancer. FAK has been suggested as a potential therapeutic target in oesophageal cancer; thus, the combination of FAK inhibitors with chemotherapy, radiotherapy, and immunotherapy is expected to prolong the survival of patients. This paper presents a brief overview of the structure of FAK and its potential role in oesophageal cancer, providing a rationale for the future application of FAK inhibitors in the treatment of the disease.
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http://dx.doi.org/10.1016/j.canlet.2020.10.005DOI Listing
January 2021

Several critical genes and microRNAs associated with the development of polycystic ovary syndrome.

Ann Endocrinol (Paris) 2020 Feb 11;81(1):18-27. Epub 2019 Nov 11.

Department of Reproductive Medicine, Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China. Electronic address:

Background: We aimed to identify key genes and microRNAs (miRNAs) associated with the development of polycystic ovary syndrome (PCOS).

Methods: GSE84376 mRNA microarray data (15 PCOS granulosa cells and 13 control granulosa cells) and GSE34526 mRNA microarray data (7 PCOS granulosa cells and 3 control granulosa cells) were downloaded from the Gene Expression Omnibus (GEO) database. First, differentially expressed gene (DEG) analysis, gene set enrichment analysis (GSEA) for differentially expressed mRNAs, and protein-protein interaction (PPI) network analysis were conducted. Next, miRNA-target genes were analyzed and functions predicted, and a competing endogenous RNA (ceRNA) network was constructed. Finally, the relationship between miR-486-5p and PRELID2 was experimentally validated.

Results: Spleen tyrosine kinase (SYK), major histocompatibility complex, class II, DR alpha (HLA-DRA), and interleukin 10 (IL-10) were important nodes in the PPI network. Interestingly, HLA-DRA was significantly enriched in phagosomes mediated by Staphylococcus aureus infection, and in IL-10 enriched during S. aureus infection. One miRNA (miR-486-5p) and a single target gene (PRELID2) were obtained from the ceRNA network. Further experiments showed that miR-486-5p is upregulated and PRELID2 is downregulated in PCOS patient granulosa cells, and that miR-486-5p targets the PRELID2 3'UTR. Topological property analysis showed that hsa-miR-4687-5p downregulation and hsa-miR-4651 upregulation determined the levels of most mRNAs. Levels of the hsa-miR-4651 target gene were significantly enriched in the leukocyte transendothelial migration pathway.

Conclusions: Our results suggest that HLA-DRA and IL-10 may contribute to PCOS progression via phagosome enriched by S. aureus infection, while miR-486-5p may be implicated in follicular development in PCOS by targeting PRELID2. Besides, miR-4651 may be involved in inflammation via leukocyte transendothelial migration, by regulating its target gene. These findings may indicate new directions and constitute a breakthrough in studying the pathophysiology of PCOS.
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http://dx.doi.org/10.1016/j.ando.2019.10.002DOI Listing
February 2020

Hypoxia induced changes in miRNAs and their target mRNAs in extracellular vesicles of esophageal squamous cancer cells.

Thorac Cancer 2020 03 10;11(3):570-580. Epub 2020 Jan 10.

Department of Radiation Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.

Background: Extracellular vesicles (EVs) are endogenous membrane vesicles with a diameter of 30-200 nm. It has been reported that hypoxic cancer cells can release numerous EVs to mediate multiple regional and systemic effects in the tumor microenvironment.

Methods: In this study, we used ultracentrifugation to extract EVs secreted by TE-13, an esophageal squamous carcinoma (ESCC) cell line during normoxia and hypoxia and performed high-throughput sequencing to detect exosomal miRNAs. Gene ontology (GO) and KEGG pathway analyses were used to reveal pathways potentially regulated by the miRNAs.

Results: A total of 10 810 miRNAs were detected; 50 were significantly upregulated and 34 were significantly downregulated under hypoxic environment. GO analysis identified enrichment of protein binding, regulation of transcription (DNA-templated), and membrane as molecular function, biological process, and cellular component, respectively. KEGG pathway analysis revealed cancer-associated pathways, phospholipase D signaling pathway, autophagy, focal adhesion and AGE-RAGE signaling as the key pathways. Further verification experiment from qRT-PCR indicated that miR-128-3p, miR-140-3p, miR-340-5p, miR-452-5p, miR-769-5p and miR-1304-p5 were significantly upregulated in EVs from hypoxia TE-13 cells while miR-340-5p was significantly upregulated in two other ESCC cells, ECA109 and TE-1.

Conclusion: This study, for the first time reveals changes in the expression of exosomal miRNAs in hypoxic ESCC cells and these findings will act as a resource to study the hypoxic tumor microenvironment and ESCC EVs.
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http://dx.doi.org/10.1111/1759-7714.13295DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7049507PMC
March 2020

Early Path Nursing on Neurological Function Recovery of Cerebral Infarction.

Transl Neurosci 2019 2;10:160-163. Epub 2019 Oct 2.

Emergency Department, Hangzhou first people's hospital, Zhejiang, China.

Purpose: to study the application of path type early rehabilitation nursing in the nursing of patients with cerebral infarction and to explore its impact on the recovery of neurological function.

Methods: Patients with acute cerebral infarction in our hospital were randomly divided into two groups. The control group used conventional treatment methods. The experimental group used path type early rehabilitation care based on conventional treatment methods and observed the curative effect.

Results: The NIHSS scores in the experimental group were significantly lower than those in the control group, and the P value was less than 0.05, which was statistically significant.

Conclusion: Path type early rehabilitation nursing has a positive effect on the treatment of patients with cerebral infarction, which contributes to the recovery of neurological function of patients and is worthy of promotion in treatment.
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http://dx.doi.org/10.1515/tnsci-2019-0028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6778399PMC
October 2019

CDK11 safeguards the identity of human embryonic stem cells via fine-tuning signaling pathways.

J Cell Physiol 2020 05 15;235(5):4279-4290. Epub 2019 Oct 15.

CAS Key Laboratory of Tissue Microenvironment and Tumor, Chinese Academy of Sciences, Shanghai, China.

Signaling pathways transmit extracellular cues into cells and regulate transcriptome and epigenome to maintain or change the cell identity. Protein kinases and phosphatases are critical for signaling transduction and regulation. Here, we report that CDK11, a member of the CDK family, is required for the maintenance of human embryonic stem cell (hESC) self-renewal. Our results show that, among the three main isoforms of CDK11, CDK11 is the main isoform safeguarding the hESC identity. Mechanistically, CDK11 constrains two important mitogen-activated protein kinase (MAPK) signaling pathways (JNK and p38 signaling) through modulating the activity of protein phosphatase 1. Furthermore, CDK11 knockdown activates transforming growth factor β (TGF-β)/SMAD2/3 signaling and upregulates certain nonneural differentiation-associated genes. Taken together, this study uncovers a kinase required for hESC self-renewal through fine-tuning MAPK and TGF-β signaling at appropriate levels. The kinase-phosphatase axis reported here may shed new light on the molecular mechanism sustaining the identity of hESCs.
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http://dx.doi.org/10.1002/jcp.29305DOI Listing
May 2020

Response prediction to oxaliplatin plus 5-fluorouracil chemotherapy in patients with colorectal cancer using a four-protein immunohistochemical model.

Oncol Lett 2019 Aug 14;18(2):2091-2101. Epub 2019 Jun 14.

Department of Medical Oncology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Dongcheng, Beijing 100730, P.R. China.

The response of cancer patients to oxaliplatin combined with 5-fluorouracil (5-FU) is difficult to predict. It has been reported that carcinoma-associated fibroblasts (CAFs) could induce AKT and ERK phosphorylation, and upregulate survivin expression in colorectal cancer (CRC) cells, which could lead to oxaliplatin plus 5-FU resistance. A total of 71 patients with advanced CRC (aCRC) treated with oxaliplatin plus 5-FU were included in the present study. These patients comprised 46 chemotherapy responders and 25 non-responders. The expression levels of α-smooth muscle actin (α-SMA), phosphorylated (p)-AKT, p-ERK and survivin were determined by immunohistochemical evaluation of paraffin-embedded samples from patients. A predictive model was established using a Probabilistic Neural Network model. The high expression of α-SMA, p-AKT and survivin in patients with aCRC were associated with oxaliplatin plus 5-FU resistance (P<0.001, P=0.023 and P=0.001, respectively). Furthermore, patients with stage IV CRC exhibiting high expression levels of α-SMA and survivin experienced a reduced progression-free survival time compared with patients with low expressions of α-SMA and survivin (5.5 vs. 15.0 months; 5.5 vs. 15.0 months; P=0.005 and P=0.001, respectively). Stage IV CRC and high survivin expression predicted a reduced overall survival time compared with that for patients with stage IV CRC and low survivin expression (50.0 vs. 15.0 months; P<0.001). Patients with α-SMA, p-AKT, p-ERK and survivin overexpression were more likely to present with intrinsic resistance to the oxaliplatin plus 5-FU regimen (the accuracies of modeling, validation and prediction were 83.7, 92.9 and 85.7%, respectively). In conclusion, the multifactorial predictive biomarker model of α-SMA, p-AKT, p-ERK and survivin expression for patients with aCRC to predict intrinsic resistance to oxaliplatin plus 5-FU regimens is of great efficiency and accuracy. Patients with high expression of this predictive model may be intrinsically resistant to the oxaliplatin and 5-FU regimen.
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http://dx.doi.org/10.3892/ol.2019.10474DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6607064PMC
August 2019

generated hematopoietic stem cells from genome edited induced pluripotent stem cells are functional in platelet-targeted gene therapy of murine hemophilia A.

Haematologica 2020 04 11;105(4):e175-e179. Epub 2019 Jul 11.

State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China

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http://dx.doi.org/10.3324/haematol.2019.219089DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7109733PMC
April 2020

Simultaneous removal of nitrogen oxides and sulfur dioxide using ultrasonically atomized hydrogen peroxide.

Environ Sci Pollut Res Int 2019 Aug 1;26(22):22351-22361. Epub 2019 Jun 1.

School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China.

A new method was developed for denitrification and desulfurization using hydrogen peroxide with the aid of an ultrasonic nebulizer to obtain high removal efficiency of NOx and SO. Comparing with the atomizing nozzles having the aperture size of 0.01~0.02 mm, the droplets generated using the ultrasonic nebulizer show the smallest d value of 7.2 μm, with 72% possessing the size less than 10 μm. Based on the numerical simulation of the vaporization rate of droplets, it is indicated that the droplets with the size of 7.2 μm can be vaporized totally at very short residence time (0.11 s) under 130 °C. Effects of influence factors including the reaction temperature, the initial HO concentration, pH value, and the flue gas flow rate were studied on the removal efficiencies of NO and SO. Using the in-series double-oxidation subsystems with HO concentration of 6 wt%, pH 5.0, and the reaction temperature of 130 °C, the removal efficiencies of SO and NO are respectively 100% and 89.3% at the short residence time of 1.8 s, and the removal efficiency of NO can be increased to 100% as the residence time is longer than 3.7 s. It is confirmed that the ultrasonically atomized HO can indeed enhance the removal efficiencies of NO and SO at the optimal temperature, owing to the fast vaporization rate of fine droplets as well as the formation of more active radicals to be captured by NO and SO simultaneously. The results here provide a promising route to remove effectively the emissions of NO and SO simultaneously. Graphical abstract.
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http://dx.doi.org/10.1007/s11356-019-05531-1DOI Listing
August 2019

deletion elevates c-JUN protein level and impairs mesoderm differentiation.

J Biol Chem 2019 06 15;294(25):9959-9972. Epub 2019 May 15.

From the Basic Clinical Research Center, Renji Hospital and Shanghai Key Laboratory of Reproductive Medicine, Department of Histoembryology, Genetics and Developmental Biology, Shanghai Jiao Tong University School of Medicine, 227 South Chongqing Road, Shanghai 200025, China,

Mesoderm development is a finely tuned process initiated by the differentiation of pluripotent epiblast cells. Serine/threonine kinase 40 (STK40) controls the development of several mesoderm-derived cell types, its overexpression induces differentiation of mouse embryonic stem cells (mESCs) toward the extraembryonic endoderm, and knockout (KO) results in multiple organ failure and is lethal at the perinatal stage in mice. However, molecular mechanisms underlying the physiological functions of STK40 in mesoderm differentiation remain elusive. Here, we report that ablation impairs mesoderm differentiation both and Mechanistically, STK40 interacts with both the E3 ubiquitin ligase mammalian constitutive photomorphogenesis protein 1 (COP1) and the transcriptional regulator proto-oncogene c-Jun (c-JUN), promoting c-JUN protein degradation. Consequently, knockout leads to c-JUN protein accumulation, which, in turn, apparently suppresses WNT signaling activity and impairs the mesoderm differentiation process. Overall, this study reveals that STK40, together with COP1, represents a previously unknown regulatory axis that modulates the c-JUN protein level within an appropriate range during mesoderm differentiation from mESCs. Our findings provide critical insights into the molecular mechanisms regulating the c-JUN protein level and may have potential implications for managing cellular disorders arising from c-JUN dysfunction.
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http://dx.doi.org/10.1074/jbc.RA119.007840DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6597834PMC
June 2019

Effects of Gastric Cancer Cell-Derived Exosomes on the Immune Regulation of Mesenchymal Stem Cells by the NF-kB Signaling Pathway.

Stem Cells Dev 2019 04 5;28(7):464-476. Epub 2019 Mar 5.

1 Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Peking Union Medical College Hospital, Center of Excellence in Tissue Engineering Chinese Academy of Medical Sciences, Beijing Key Laboratory (No. BZO381), Beijing, People's Republic of China.

Mesenchymal stem cells (MSCs) are important components of the tumor microenvironment, which play an important role in tumor development. Exosomes derived from tumor cells can affect the biological characteristics of MSCs. Our study examined the effects of exosomes derived from gastric cancer cells on MSC immunomodulatory functions. Exosomes were extracted from gastric cancer cell line AGS (AGS-Exos) and cultured with MSCs. MSCs were then cocultured with both human peripheral blood mononuclear cells and macrophages [phorbol-12-myristate-13-acetate (PMA)-stimulated THP1 cells]. The activation levels of T cells and macrophages were detected by flow cytometry and real-time quantitative polymerase chain reaction (RT-PCR). Changes in the MSC signaling pathway after AGS-Exos stimulation were studied using RNA Chip, and the molecular mechanisms of functional change in MSCs were studied by inhibiting the signaling pathway. MSCs treated with AGS-Exos could promote macrophage phagocytosis and upregulate the secretion of proinflammatory factor, and promote the activation of CD69 and CD25 on the surface of T cells. RNA Chip results indicated the abnormal activation of the NF-kB signaling pathway in MSCs after AGS-Exos stimulation, and this was verified by the identification of key proteins in the pathway using western blot analysis. After NF-kB signaling pathway inhibition, the effect of MSCs stimulated by AGS-Exos on T cells and macrophages was markedly weakened. Therefore, AGS-Exos affected the immunomodulation function of MSCs through the NF-kB signaling pathway, which enhanced the ability of MSCs to activate immune cells, maintain the inflammatory environment, and support tumor growth.
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http://dx.doi.org/10.1089/scd.2018.0125DOI Listing
April 2019

Disruption of OCT4 Ubiquitination Increases OCT4 Protein Stability and ASH2L-B-Mediated H3K4 Methylation Promoting Pluripotency Acquisition.

Stem Cell Reports 2018 10 27;11(4):973-987. Epub 2018 Sep 27.

Basic Clinical Research Center, Renji Hospital, Department of Histology, Genetics and Developmental Biology, Shanghai Key Laboratory of Reproductive Medicine, Shanghai JiaoTong University School of Medicine, 227 South Chongqing Road, Shanghai 200025, China. Electronic address:

The protein level of OCT4, a core pluripotency transcription factor, is vital for embryonic stem cell (ESC) maintenance, differentiation, and somatic cell reprogramming. However, how OCT4 protein levels are controlled during reprogramming remains largely unknown. Here, we identify ubiquitin conjugation sites of OCT4 and report that disruption of WWP2-catalyzed OCT4 ubiquitination or ablation of Wwp2 significantly promotes the efficiency of pluripotency induction from mouse embryonic fibroblasts. Mechanistically, disruption of WWP2-mediated OCT4 ubiquitination elevates OCT4 protein stability and H3K4 methylation level during the reprogramming process. Furthermore, we reveal that OCT4 directly activates expression of Ash2l-b, and that ASH2L-B is a major isoform of ASH2L highly expressed in ESCs and required for somatic cell reprogramming. Together, this study emphasizes the importance of ubiquitination manipulation of the reprogramming factor and its interplay with the epigenetic regulator for successful reprogramming, opening a new avenue to improve the efficiency of pluripotency induction.
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http://dx.doi.org/10.1016/j.stemcr.2018.09.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6178847PMC
October 2018

Transcription coactivator Cited1 acts as an inducer of trophoblast-like state from mouse embryonic stem cells through the activation of BMP signaling.

Cell Death Dis 2018 09 11;9(9):924. Epub 2018 Sep 11.

Basic Clinical Research Center, Renji Hospital, Department of Histology, Genetics and Developmental Biology, Shanghai Key Laboratory of Reproductive Medicine, Shanghai JiaoTong University School of Medicine, 225 South Chongqing Road, 200025, Shanghai, China.

Trophoblast lineages, precursors of the placenta, are essential for post-implantation embryo survival. However, the regulatory network of trophoblast development remains incompletely understood. Here, we report that Cited1, a transcription coactivator, is a robust inducer for trophoblast-like state from mouse embryonic stem cells (ESCs). Depletion of Cited1 in ESCs compromises the trophoblast lineage specification induced by BMP signaling. In contrast, overexpression of Cited1 in ESCs induces a trophoblast-like state with elevated expression of trophoblast marker genes in vitro and generation of trophoblastic tumors in vivo. Furthermore, global transcriptome profile analysis indicates that ectopic Cited1 activates a trophoblast-like transcriptional program in ESCs. Mechanistically, Cited1 interacts with Bmpr2 and Smad4 to activate the Cited1-Bmpr2-Smad1/5/8 axis in the cytoplasm and Cited1-Smad4-p300 complexes in the nucleus, respectively. Collectively, our results show that Cited1 plays an important role in regulating trophoblast lineage specification through activating the BMP signaling pathway.
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http://dx.doi.org/10.1038/s41419-018-0991-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6134011PMC
September 2018

Graphene oxide encapsulated polyvinyl alcohol/sodium alginate hydrogel microspheres for Cu (II) and U (VI) removal.

Ecotoxicol Environ Saf 2018 Aug 2;158:309-318. Epub 2018 May 2.

College of Chemistry, Fuzhou University, Fuzhou 350108, China. Electronic address:

In this work, a novel sodium alginate (SA)/polyvinyl alcohol (PVA)/graphene oxide (GO) hydrogel microspheres were prepared by a simple method. Sodium alginate was physically crosslinked by Ca; GO was encapsulated into the composite to strengthen the hydrogels; PVA played a significant role in well dispersing of GO in SA. The SA/PVA/GO (SPG) hydrogels were employed as an efficient adsorbent for removal of Cu (II) and U (VI) from aqueous solution. Batch experiments with the subject of the pH, initial metal ion concentration, competing ions and contact time were investigated. Structure characterization was successfully conducted by FTIR, SEM, EDX, BET and XPS. Furthermore, the sorption kinetics of Cu and UO followed pseudo-second order model and exhibited 3-stage intraparticle diffusion model. Equilibrium data were best described by Langmuir model and the obtained maximum adsorption capacities of SPG hydrogel microspheres for Cu and UO were 247.16 and 403.78 mg/g, respectively. The difference in adsorption capacity can be confirmed by the percentage of elements in EDX spectra and the intension of peak of elements in XPS spectra. The SPG sorbent exhibited excellent reusability after 5 adsorption-desorption cycles. All results suggested that the prepared adsorbents could be considered as effective and promising materials for removal of Cu (II) and U (VI) in wastewater.
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http://dx.doi.org/10.1016/j.ecoenv.2018.04.039DOI Listing
August 2018

Exosomes Derived from Hypoxia-Treated Human Adipose Mesenchymal Stem Cells Enhance Angiogenesis Through the PKA Signaling Pathway.

Stem Cells Dev 2018 04 20;27(7):456-465. Epub 2018 Mar 20.

1 Beijing Key Laboratory (No. BZO381), Center of Excellence in Tissue Engineering Chinese Academy of Medical Sciences, Peking Union Medical College Hospital, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences , Beijing, People's Republic of China .

Angiogenesis is a complicated and sequential process that plays an important role in different physiological processes. Mesenchymal stem cells (MSCs), which are pluripotent stem cells, are widely used for the treatment of ischemic and traumatic diseases, and exosomes derived from these cells can also promote angiogenesis. Therefore, we aimed to uncover mechanisms to improve MSC exosome-mediated angiogenesis. For this study, we isolated human adipose-derived MSCs (hAD-MSCs) and assessed differentiation ability and markers. Cells were divided into hypoxia-treated MSCs (H-MSCs) and normoxia-treated MSCs (N-MSC), and exosomes were extracted by ultrafiltration. Exosomes (100 μg/mL) from H-MSCs and N-MSCs were added to human umbilical vein endothelial cells (HUVECs). Exosome uptake and the ability of endothelial cells to form tubes were detected in real time. Protein samples were collected at different time points to detect the expression of inhibitors (Vash1) and enhancers (Angpt1 and Flk1) of angiogenesis; we also assessed their related signaling pathways. We found that exosomes from the hypoxia group were more easily taken up by HUVECs; furthermore, their angiogenesis stimulatory activity was also significantly enhanced compared to that with exosomes from the normoxia group. HUVECs exposed to exosomes from H-MSCs significantly upregulated angiogenesis-stimulating genes and deregulated angiogenesis-inhibitory genes. The expression of vascular endothelial growth factor (VEGF) and activation of the protein kinase A (PKA) signaling pathway in HUVECs were significantly increased by hypoxia-exposed exosomes. Moreover, a PKA inhibitor was shown to significantly suppress angiogenesis. Finally, we concluded that hypoxia-exposed exosomes derived from hAD-MSCs can improve angiogenesis by activating the PKA signaling pathway and promoting the expression of VEGF. These results could be used to uncover safe and effective treatments for traumatic diseases.
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http://dx.doi.org/10.1089/scd.2017.0296DOI Listing
April 2018

Enhanced removal of Cr(VI) from aqueous solution by supported ZnO nanoparticles on biochar derived from waste water hyacinth.

Chemosphere 2018 Mar 22;195:632-640. Epub 2017 Dec 22.

Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, PR China. Electronic address:

Biochar derived from waste water hyacinth was prepared and modified by ZnO nanoparticles for Cr(VI) removal from aqueous solution with the aim of Cr(VI) removal and management of waste biomass. The effect of carbonization temperature (500-800 °C), ZnO content (10-50 wt%) loaded on biochar and contact time (0.17-14 h) on the Cr(VI) removal were investigated. It was found that higher than 95% removal efficiency of Cr(VI) can be achieved with the biochar loaded 30 wt% ZnO. The adsorption kinetics of the sorbent is consistent with the pseudo-second-order kinetic model and adsorption isotherm follows the Langmuir model with maximum adsorption capacity of 43.48 mg g for Cr(VI). Multiple techniques such as XRD, XPS, SEM, EDX and FT-IR were performed to investigate the possible mechanisms involved in the Cr (VI) adsorption. The results show that there is precipitation between chromium ions and Zn oxide. Furthermore, the ZnO nanoparticles acts as photo-catalyst to generate photo-generated electrons to enhance the reduction of Cr(VI) to Cr(III). The as-prepared ZnO/BC possess good recyclability and the removal ratio remained at about 70% in the fifth cycle, which suggests that both contaminants removal and effective management of water hyacinth can be achieved by the approach.
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http://dx.doi.org/10.1016/j.chemosphere.2017.12.128DOI Listing
March 2018

Modification of chitosan/calcium alginate/FeO hydrogel microsphere for enhancement of Cu(II) adsorption.

Environ Sci Pollut Res Int 2018 Feb 25;25(4):3922-3932. Epub 2017 Nov 25.

College of Chemistry, Fuzhou University, Fuzhou, 350108, China.

Copper in drinking water causes a significant environmental problem. Composite material based on alginate hydrogel has been gaining attention in the field of Cu(II) adsorption. However, alginate-based hydrogel exhibits poor mechanical property and relative low adsorption capacity which limit their application. The present study is devoted to the modification of chitosan/calcium alginate/FeO (CAF) hydrogel microsphere by NaOH solution for enhancement of Cu(II) adsorption. Results reveal that modification of CAF via NaOH solution significantly improves the mechanical strength and Cu adsorption capacity of pristine materials. FTIR and XRD analysis confirms that CAF and newly prepared materials (NACAF) are successfully prepared. SEM and EDX are employed to analyze the surface morphology and elemental composition, respectively, both before and after their loading with Cu. XPS study demonstrates adsorption mechanism is based on chelation and ion-exchange. Compressive stress-strain curves demonstrate NACAF has better mechanical performance than CAF. The adsorption kinetics of the two adsorbents follow a pseudo-second-order model. The equilibrium data were best described by Langmuir isotherm model, and the estimated maximum equilibrium sorption capacity, q ,is 261.31 mg/g for the NACAF, which is larger than that of CAF (145.39 mg/g). Hence, NACAF shows excellent mechanical strength and high sorption capacity for Cu. It has great potential for Cu(II) removal in aqueous solutions.
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http://dx.doi.org/10.1007/s11356-017-0802-8DOI Listing
February 2018

Steroid hormone profiling in obese and nonobese women with polycystic ovary syndrome.

Sci Rep 2017 10 26;7(1):14156. Epub 2017 Oct 26.

Shanghai National Clinical Research Center for Endocrine and Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of Chinese Ministry of Health, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China.

The study explored differences in the steroidogenic pathway between obese and nonobese women with polycystic ovary syndrome (PCOS) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). 1044 women with PCOS (including 350 lean, 312 overweight and 382 obese) and 366 control women without PCOS (including 203 lean, 32 overweight and 131 obese) were enrolled. The differences in steroid hormones were amplified in lean PCOS versus lean controls compared with obese PCOS versus obese controls. Compared with obese PCOS, lean PCOS demonstrated increased dehydroepiandrosterone sulfate (P = 0.015), 17-hydropregnenolone (P = 0.003), 17-hydroprogesterone (17-OHP) (P < 0.001), progesterone (P < 0.001) and estrone (P < 0.001) levels. Enzyme activity evaluation showed that lean PCOS had increased activity of P450c17 (17-hydropregnenolone/pregnenolone, P < 0.001), P450aro (P < 0.001), 3βHSD2 (progesterone/ pregnenolone and 17-OHP/17-hydropregnenolone, both P < 0.001) and decreased activity of P450c21(11-deoxycorticorsterone/progesterone and 11-deoxycortisol/17-OHP, P < 0.001). Moreover, we found higher frequencies of CYP21A2- (encoding P450c21) c.552 C > G (p. D184E) in lean PCOS compared with obese PCOS patients (P = 0.006). In conclusion, this study demonstrated for the first time that the adrenal-specific enzyme P450c21 showed decreased activity in lean PCOS patients, and that the adrenal androgen excess may play different roles in lean and obese PCOS patients, which represents as different enzyme activity in the steroidogenic pathway.
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http://dx.doi.org/10.1038/s41598-017-14534-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5658378PMC
October 2017

Encapsulating FeO into calcium alginate coated chitosan hydrochloride hydrogel beads for removal of Cu (II) and U (VI) from aqueous solutions.

Ecotoxicol Environ Saf 2018 Jan 19;147:699-707. Epub 2017 Sep 19.

College of Chemistry, Fuzhou University, Fuzhou 350108, China. Electronic address:

The aim of this work was to study the removal of Cu (II) and U (VI) ions from aqueous solutions by encapsulating magnetic FeO nanoparticles into calcium alginate coated chitosan hydrochloride (CCM) hydrogel beads. ATR-FTIR and XRD analysis data indicated that the CCM composites were successfully prepared. SEM images and EDX spectra showed that Cu and UO ions were adhered onto sorbents. Adsorption properties for removal of both copper and uranium ions under various experimental conditions were investigated. Kinetic data and sorption equilibrium isotherms were also conducted in batch process. The sorption kinetic analysis revealed that sorption of Cu (II) and U (VI) followed the pseudo-second-order model well and exhibited 3-stage intraparticle diffusion model during the whole sorption process. Equilibrium data were best described by Langmuir model, and the CCM composite hydrogel beads showed the estimated maximum adsorption capacity 143.276mg/g and 392.692mg/g for Cu (II) and U (VI), respectively. The CCM adsorbent exhibited excellent reusability for five cycles use without significant changes in the adsorption capacity and structural stability. The results demonstrated that CCM can be an effective and promising sorbent for Cu (II) and U (VI) ions in wastewater.
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http://dx.doi.org/10.1016/j.ecoenv.2017.09.036DOI Listing
January 2018

JMJD1C Ensures Mouse Embryonic Stem Cell Self-Renewal and Somatic Cell Reprogramming through Controlling MicroRNA Expression.

Stem Cell Reports 2017 09 17;9(3):927-942. Epub 2017 Aug 17.

Key Laboratory of Stem Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China; Department of Histoembryology, Genetics and Developmental Biology, Institute of Medical Sciences, Shanghai JiaoTong University School of Medicine, 225 South Chongqing Road, Shanghai 200025, China. Electronic address:

The roles of histone demethylases (HDMs) for the establishment and maintenance of pluripotency are incompletely characterized. Here, we show that JmjC-domain-containing protein 1c (JMJD1C), an H3K9 demethylase, is required for mouse embryonic stem cell (ESC) self-renewal. Depletion of Jmjd1c leads to the activation of ERK/MAPK signaling and epithelial-to-mesenchymal transition (EMT) to induce differentiation of ESCs. Inhibition of ERK/MAPK signaling rescues the differentiation phenotype caused by Jmjd1c depletion. Mechanistically, JMJD1C, with the help of pluripotency factor KLF4, maintains ESC identity at least in part by regulating the expression of the miR-200 family and miR-290/295 cluster to suppress the ERK/MAPK signaling and EMT. Additionally, we uncover that JMJD1C ensures efficient generation and maintenance of induced pluripotent stem cells, at least partially through controlling the expression of microRNAs. Collectively, we propose an integrated model of epigenetic and transcriptional control mediated by the H3K9 demethylase for ESC self-renewal and somatic cell reprogramming.
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http://dx.doi.org/10.1016/j.stemcr.2017.07.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5599225PMC
September 2017

Single-cell analysis reveals lineage segregation in early post-implantation mouse embryos.

J Biol Chem 2017 06 15;292(23):9840-9854. Epub 2017 Mar 15.

From the Key Laboratory of Stem Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences/Shanghai JiaoTong University School of Medicine, Shanghai 200031,

The mammalian post-implantation embryo has been extensively investigated at the tissue level. However, to unravel the molecular basis for the cell-fate plasticity and determination, it is essential to study the characteristics of individual cells. In particular, the individual definitive endoderm (DE) cells have not been characterized Here, we report gene expression patterns in single cells freshly isolated from mouse embryos on days 5.5 and 6.5. Initial transcriptome data from 124 single cells yielded signature genes for the epiblast, visceral endoderm, and extra-embryonic ectoderm and revealed a unique distribution pattern of fibroblast growth factor (FGF) ligands and receptors. Further analysis indicated that early-stage epiblast cells do not segregate into lineages of the major germ layers. Instead, some cells began to diverge from epiblast cells, displaying molecular features of the premesendoderm by expressing higher levels of mesendoderm markers and lower levels of transcripts. Analysis of single-cell high-throughput quantitative RT-PCR data from 441 cells identified a late stage of the day 6.5 embryo in which mesoderm and DE cells emerge, with many of them coexpressing and Analysis of single-cell RNA-sequence data from 112 cells of the late-stage day 6.5 embryos revealed differentially expressed signaling genes and networks of transcription factors that might underlie the segregation of the mesoderm and DE lineages. Moreover, we discovered a subpopulation of mesoderm cells that possess molecular features of the extraembryonic mesoderm. This study provides fundamental insight into the molecular basis for lineage segregation in post-implantation mouse embryos.
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http://dx.doi.org/10.1074/jbc.M117.780585DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5465504PMC
June 2017

The chromatin remodeler Chd4 maintains embryonic stem cell identity by controlling pluripotency- and differentiation-associated genes.

J Biol Chem 2017 05 15;292(20):8507-8519. Epub 2017 Mar 15.

Key Laboratory of Stem Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences/Shanghai JiaoTong University School of Medicine, 320 Yueyang Road, Shanghai 200031, China; Laboratory of Molecular Developmental Biology, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China. Electronic address:

The unique properties of embryonic stem cells (ESCs), including unlimited self-renewal and pluripotent differentiation potential, are sustained by integrated genetic and epigenetic networks composed of transcriptional factors and epigenetic modulators. However, the molecular mechanisms underlying the function of these regulators are not fully elucidated. Chromodomain helicase DNA-binding protein 4 (Chd4), an ATPase subunit of the nucleosome remodeling and deacetylase (NuRD) complex, is highly expressed in ESCs. However, its function in ESC regulation remains elusive. Here we report that Chd4 is required for the maintenance of ESC self-renewal. RNAi-mediated silencing of Chd4 disrupted self-renewal and up-regulated lineage commitment-associated genes under self-renewal culture conditions. During ESC differentiation in embryoid body formation, we observed significantly stronger induction of differentiation-associated genes in Chd4-deficient cells. The phenotype was different from that caused by the deletion of Mbd3, another subunit of the NuRD complex. Transcriptomic analyses revealed that Chd4 secured ESC identity by controlling the expression of subsets of pluripotency- and differentiation-associated genes. Importantly, Chd4 repressed the transcription of T box protein 3 (Tbx3), a transcription factor with important functions in ESC fate determination. Tbx3 knockdown partially rescued aberrant activation of differentiation-associated genes, especially of endoderm-associated genes, induced by Chd4 depletion. Moreover, we identified an interaction of Chd4 with the histone variant H2A.Z. This variant stabilized Chd4 by inhibiting Chd4 protein degradation through the ubiquitin-proteasome pathway. Collectively, this study identifies the Chd4-Tbx3 axis in controlling ESC fate and a role of H2A.Z in maintaining the stability of Chd4 proteins.
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http://dx.doi.org/10.1074/jbc.M116.770248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5437254PMC
May 2017

PHB Associates with the HIRA Complex to Control an Epigenetic-Metabolic Circuit in Human ESCs.

Cell Stem Cell 2017 02 8;20(2):274-289.e7. Epub 2016 Dec 8.

Key Laboratory of Stem Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences/Shanghai JiaoTong University School of Medicine, 320 Yueyang Road, Shanghai 200032, China; Department of Molecular Developmental Biology, Institute of Medical Sciences, Shanghai JiaoTong University School of Medicine, 225 South Chongqing Road, Shanghai 200025, China. Electronic address:

The chromatin landscape and cellular metabolism both contribute to cell fate determination, but their interplay remains poorly understood. Using genome-wide siRNA screening, we have identified prohibitin (PHB) as an essential factor in self-renewal of human embryonic stem cells (hESCs). Mechanistically, PHB forms protein complexes with HIRA, a histone H3.3 chaperone, and stabilizes the protein levels of HIRA complex components. Like PHB, HIRA is required for hESC self-renewal. PHB and HIRA act together to control global deposition of histone H3.3 and gene expression in hESCs. Of particular note, PHB and HIRA regulate the chromatin architecture at the promoters of isocitrate dehydrogenase genes to promote transcription and, thus, production of α-ketoglutarate, a key metabolite in the regulation of ESC fate. Our study shows that PHB has an unexpected nuclear role in hESCs that is required for self-renewal and that it acts with HIRA in chromatin organization to link epigenetic organization to a metabolic circuit.
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http://dx.doi.org/10.1016/j.stem.2016.11.002DOI Listing
February 2017