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1.
Polymers (Basel) ; 15(12)2023 Jun 20.
Article in English | MEDLINE | ID: mdl-37376397

ABSTRACT

It is a great challenge to develop low-cost and dopant-free polymer hole-transporting materials (HTM) for PSCs, especially for efficient air-processed inverted (p-i-n) planar PSCs. A new homopolymer HTM, poly(2,7-(9,9-bis(N,N-di-p-methoxylphenyl amine)-4-phenyl))-fluorene (denoted as PFTPA), with appropriate photo-electrochemical, opto-electronic and thermal stability, was designed and synthesized in two steps to meet this challenge. By employing PFTPA as dopant-free hole-transport layer in air-processed inverted PSCs, a champion power conversion efficiency (PCE) of up to 16.82% (0.1 cm2) was achieved, much superior to that of commercial HTM PEDOT:PSS (13.8%) under the same conditions. Such a superiority is attributed to the well-aligned energy levels, improved morphology, and efficient hole-transporting, as well as hole-extraction characteristics at the perovskite/HTM interface. In particular, these PFTPA-based PSCs fabricated in the air atmosphere maintain a long-term stability of 91% under ambient air conditions for 1000 h. Finally, PFTPA as the dopant-free HTM was also fabricated the slot-die coated perovskite device through the same fabrication condition, and a maximum PCE of 13.84% was obtained. Our study demonstrated that the low-cost and facile homopolymer PFTPA as the dopant-free HTM are potential candidates for large-scale production perovskite solar cell.

2.
Sci Rep ; 13(1): 6024, 2023 Apr 13.
Article in English | MEDLINE | ID: mdl-37055451

ABSTRACT

As the particularly popular green energy, geothermal resources are gradually favored by countries around the world, and the development model centered on geothermal dew point cannot meet the increasing geothermal demand. In this paper, a GIS model combining PCA and AHP is proposed, aiming to select the advantages of geothermal resources at the regional scale and analyze the main influencing indicators. Through the combination of the two methods, both data and empirical can be considered, then the geothermal advantage distribution on the area can be displayed through GIS software images. A multi-index evaluation system is established to qualitatively and quantitatively evaluate the mid-high temperature geothermal resources in Jiangxi Province, and carry out the evaluation of the dominant target areas and the analysis of geothermal impact indicators. The results show that it is divided into 7 geothermal resource potential areas and 38 geothermal advantage targets, and the determination of deep fault is the most critical index of geothermal distribution. This method is suitable for large-scale geothermal research, multi-index and multi-data model analysis and precise positioning of high-quality geothermal resource targets, which can meet the needs of geothermal research at the regional scale.

3.
Nat Cancer ; 4(1): 62-80, 2023 01.
Article in English | MEDLINE | ID: mdl-36585453

ABSTRACT

Pancreatic ductal adenocarcinoma (PDAC) is considered non-immunogenic, with trials showing its recalcitrance to PD1 and CTLA4 immune checkpoint therapies (ICTs). Here, we sought to systematically characterize the mechanisms underlying de novo ICT resistance and to identify effective therapeutic options for PDAC. We report that agonist 41BB and antagonist LAG3 ICT alone and in combination, increased survival and antitumor immunity, characterized by modulating T cell subsets with antitumor activity, increased T cell clonality and diversification, decreased immunosuppressive myeloid cells and increased antigen presentation/decreased immunosuppressive capability of myeloid cells. Translational analyses confirmed the expression of 41BB and LAG3 in human PDAC. Since single and dual ICTs were not curative, T cell-activating ICTs were combined with a CXCR1/2 inhibitor targeting immunosuppressive myeloid cells. Triple therapy resulted in durable complete responses. Given similar profiles in human PDAC and the availability of these agents for clinical testing, our findings provide a testable hypothesis for this lethal disease.


Subject(s)
Carcinoma, Pancreatic Ductal , Pancreatic Neoplasms , Humans , Carcinoma, Pancreatic Ductal/drug therapy , Myeloid Cells/pathology , Pancreatic Neoplasms/drug therapy , T-Lymphocyte Subsets/metabolism , T-Lymphocyte Subsets/pathology , Receptors, Interleukin-8A/immunology , Pancreatic Neoplasms
4.
Cells ; 11(19)2022 09 21.
Article in English | MEDLINE | ID: mdl-36230914

ABSTRACT

Pancreatic cancer has a notoriously poor prognosis, exhibits persistent drug resistance, and lacks a cure. Unique features of the pancreatic tumor microenvironment exacerbate tumorigenesis, metastasis, and therapy resistance. Recent studies emphasize the importance of exploiting cells in the tumor microenvironment to thwart cancers. In this review, we summarize the hallmarks of the multifaceted pancreatic tumor microenvironment, notably pancreatic stellate cells, tumor-associated fibroblasts, macrophages, and neutrophils, in the regulation of chemo-, radio-, immuno-, and targeted therapy resistance in pancreatic cancer. The molecular insight will facilitate the development of novel therapeutics against pancreatic cancer.


Subject(s)
Pancreatic Neoplasms , Tumor Microenvironment , Humans , Pancreas/pathology , Pancreatic Neoplasms/pathology , Pancreatic Stellate Cells/pathology , Tumor Microenvironment/physiology , Pancreatic Neoplasms
5.
Theranostics ; 12(13): 5691-5709, 2022.
Article in English | MEDLINE | ID: mdl-35966590

ABSTRACT

Aberrant activation of KRAS signaling is common in cancer, which has catalyzed heroic drug development efforts to target KRAS directly or its downstream signaling effectors. Recent works have yielded novel small molecule drugs with promising preclinical and clinical activities. Yet, no matter how a cancer is addicted to a specific target - cancer's genetic and biological plasticity fashions a variety of resistance mechanisms as a fait accompli, limiting clinical benefit of targeted interventions. Knowledge of these mechanisms may inform combination strategies to attack both oncogenic KRAS and subsequent bypass mechanisms.


Subject(s)
Neoplasms , Proto-Oncogene Proteins p21(ras) , Carcinogenesis/genetics , Humans , Neoplasms/drug therapy , Neoplasms/genetics , Oncogenes , Proto-Oncogene Proteins p21(ras)/genetics , Signal Transduction
6.
Oncogene ; 40(41): 6049-6056, 2021 10.
Article in English | MEDLINE | ID: mdl-34471235

ABSTRACT

Yes-associated protein 1 (YAP1), a key player in the Hippo pathway, has been shown to play a critical role in tumor progression. However, the role of YAP1 in prostate cancer cell invasion, migration, and metastasis is not well defined. Through functional, transcriptomic, epigenomic, and proteomic analyses, we showed that prolyl hydroxylation of YAP1 plays a critical role in the suppression of cell migration, invasion, and metastasis in prostate cancer. Knockdown (KD) or knockout (KO) of YAP1 led to an increase in cell migration, invasion, and metastasis in prostate cancer cells. Microarray analysis showed that the EMT pathway was activated in Yap1-KD cells. ChIP-seq analysis showed that YAP1 target genes are enriched in pathways regulating cell migration. Mass spectrometry analysis identified P4H prolyl hydroxylase in the YAP1 complex and YAP1 was hydroxylated at multiple proline residues. Proline-to-alanine mutations of YAP1 isoform 3 identified proline 174 as a critical residue, and its hydroxylation suppressed cell migration, invasion, and metastasis. KO of P4ha2 led to an increase in cell migration and invasion, which was reversed upon Yap1 KD. Our study identified a novel regulatory mechanism of YAP1 by which P4HA2-dependent prolyl hydroxylation of YAP1 determines its transcriptional activities and its function in prostate cancer metastasis.


Subject(s)
Prolyl Hydroxylases/metabolism , Prostatic Neoplasms/metabolism , YAP-Signaling Proteins/metabolism , Animals , Cell Movement/physiology , Humans , Male , Mice , Neoplasm Invasiveness , Neoplasm Metastasis , Prostatic Neoplasms/pathology , YAP-Signaling Proteins/antagonists & inhibitors
7.
Genes Dev ; 35(19-20): 1327-1332, 2021 10 01.
Article in English | MEDLINE | ID: mdl-34531315

ABSTRACT

Activating mutations in KRAS (KRAS*) are present in nearly all pancreatic ductal adenocarcinoma (PDAC) cases and critical for tumor maintenance. By using an inducible KRAS* PDAC mouse model, we identified a deubiquitinase USP21-driven resistance mechanism to anti-KRAS* therapy. USP21 promotes KRAS*-independent tumor growth via its regulation of MARK3-induced macropinocytosis, which serves to maintain intracellular amino acid levels for anabolic growth. The USP21-mediated KRAS* bypass, coupled with the frequent amplification of USP21 in human PDAC tumors, encourages the assessment of USP21 as a novel drug target as well as a potential parameter that may affect responsiveness to emergent anti-KRAS* therapy.


Subject(s)
Carcinoma, Pancreatic Ductal , Pancreatic Neoplasms , Animals , Carcinoma, Pancreatic Ductal/genetics , Carcinoma, Pancreatic Ductal/pathology , Cell Line, Tumor , Deubiquitinating Enzymes/metabolism , Mice , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/metabolism , Proto-Oncogene Proteins p21(ras)/genetics , Proto-Oncogene Proteins p21(ras)/metabolism , Ubiquitin Thiolesterase
8.
Nat Commun ; 11(1): 4766, 2020 09 21.
Article in English | MEDLINE | ID: mdl-32958778

ABSTRACT

Germline telomere maintenance defects are associated with an increased incidence of inflammatory diseases in humans, yet whether and how telomere dysfunction causes inflammation are not known. Here, we show that telomere dysfunction drives pATM/c-ABL-mediated activation of the YAP1 transcription factor, up-regulating the major pro-inflammatory factor, pro-IL-18. The colonic microbiome stimulates cytosolic receptors activating caspase-1 which cleaves pro-IL-18 into mature IL-18, leading to recruitment of interferon (IFN)-γ-secreting T cells and intestinal inflammation. Correspondingly, patients with germline telomere maintenance defects exhibit DNA damage (γH2AX) signaling together with elevated YAP1 and IL-18 expression. In mice with telomere dysfunction, telomerase reactivation in the intestinal epithelium or pharmacological inhibition of ATM, YAP1, or caspase-1 as well as antibiotic treatment, dramatically reduces IL-18 and intestinal inflammation. Thus, telomere dysfunction-induced activation of the ATM-YAP1-pro-IL-18 pathway in epithelium is a key instigator of tissue inflammation.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Cell Cycle Proteins/metabolism , Inflammation/pathology , Telomere/pathology , Adaptor Proteins, Signal Transducing/antagonists & inhibitors , Adaptor Proteins, Signal Transducing/genetics , Animals , Anti-Bacterial Agents/therapeutic use , Ataxia Telangiectasia Mutated Proteins/antagonists & inhibitors , Ataxia Telangiectasia Mutated Proteins/metabolism , Caspase 1/metabolism , Cell Cycle Proteins/antagonists & inhibitors , Cell Cycle Proteins/genetics , Child , Colon/metabolism , Colon/microbiology , Colon/pathology , Gastrointestinal Diseases/pathology , Gastrointestinal Microbiome/drug effects , Gastrointestinal Microbiome/physiology , Humans , Inflammation/drug therapy , Inflammation/metabolism , Inflammation/microbiology , Interleukin-18/genetics , Interleukin-18/metabolism , Intestinal Mucosa/metabolism , Intestinal Mucosa/pathology , Mice , Mice, Mutant Strains , Phosphorylation , Protein Precursors/genetics , Protein Precursors/metabolism , Signal Transduction , Telomerase/genetics , Telomerase/metabolism , YAP-Signaling Proteins
9.
Cancer Discov ; 10(7): 1058-1077, 2020 07.
Article in English | MEDLINE | ID: mdl-32341020

ABSTRACT

Oncogenic KRAS (KRAS*) is a key tumor maintenance gene in pancreatic ductal adenocarcinoma (PDAC), motivating pharmacologic targeting of KRAS* and its effectors. Here, we explored mechanisms involving the tumor microenvironment (TME) as a potential basis for resistance to targeting KRAS*. Using the inducible Kras G12D;Trp53 -/- PDAC mouse model, gain-of-function screens of epigenetic regulators identified HDAC5 as the top hit enabling KRAS* independent tumor growth. HDAC5-driven escaper tumors showed a prominent neutrophil-to-macrophage switch relative to KRAS*-driven tumors. Mechanistically, HDAC5 represses Socs3, a negative regulator of chemokine CCL2, resulting in increased CCL2, which recruits CCR2+ macrophages. Correspondingly, enforced Ccl2 promotes macrophage recruitment into the TME and enables tumor recurrence following KRAS* extinction. These tumor-associated macrophages in turn provide cancer cells with trophic support including TGFß to enable KRAS* bypass in a SMAD4-dependent manner. Our work uncovers a KRAS* resistance mechanism involving immune cell remodeling of the PDAC TME. SIGNIFICANCE: Although KRAS* is required for PDAC tumor maintenance, tumors can recur following KRAS* extinction. The capacity of PDAC cancer cells to alter the TME myeloid cell composition to support KRAS*-independent tumor growth illuminates novel therapeutic targets that may enhance the effectiveness of therapies targeting KRAS* and its pathway components.See related commentary by Carr and Fernandez-Zapico, p. 910.This article is highlighted in the In This Issue feature, p. 890.


Subject(s)
Oncogenes/physiology , Pancreatic Neoplasms/genetics , Proto-Oncogene Proteins p21(ras)/metabolism , Humans , Pancreatic Neoplasms/pathology , Tumor Microenvironment , Pancreatic Neoplasms
10.
Genes Dev ; 33(19-20): 1361-1366, 2019 10 01.
Article in English | MEDLINE | ID: mdl-31488580

ABSTRACT

The ubiquitin-specific protease (USP) family is the largest group of cysteine proteases. Cancer genomic analysis identified frequent amplification of USP21 (22%) in human pancreatic ductal adenocarcinoma (PDAC). USP21 overexpression correlates with human PDAC progression, and enforced expression of USP21 accelerates murine PDAC tumor growth and drives PanIN to PDAC progression in immortalized human pancreatic ductal cells. Conversely, depletion of USP21 impairs PDAC tumor growth. Mechanistically, USP21 deubiquitinates and stabilizes the TCF/LEF transcription factor TCF7, which promotes cancer cell stemness. Our work identifies and validates USP21 as a PDAC oncogene, providing a potential druggable target for this intractable disease.


Subject(s)
Gene Expression Regulation, Neoplastic/genetics , Pancreatic Neoplasms/enzymology , Ubiquitin Thiolesterase/genetics , Ubiquitin Thiolesterase/metabolism , Wnt Signaling Pathway/genetics , Animals , Cell Line, Tumor , Humans , Mice , Neoplastic Stem Cells/pathology , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/physiopathology , T Cell Transcription Factor 1 , Ubiquitination , Pancreatic Neoplasms
11.
J Zhejiang Univ Sci B ; 20(7): 613-616, 2019 Jul.
Article in English | MEDLINE | ID: mdl-31168975

ABSTRACT

The ovum oil of forest frog has various health beneficial functions. In the current research, we evaluated the hypolipidemic effects of the low-cholesterol ovum oil from the forest frog and its combination with stigmasterol in rats.


Subject(s)
Cholesterol/metabolism , Hyperlipidemias/drug therapy , Oils/pharmacology , Ranidae , Stigmasterol/pharmacology , Animals , Fatty Acids, Unsaturated/pharmacology , Female , Lipids/blood , Male , Ovum/chemistry , Rats , Rats, Sprague-Dawley
12.
Nature ; 568(7752): 410-414, 2019 04.
Article in English | MEDLINE | ID: mdl-30918400

ABSTRACT

Pancreatic ductal adenocarcinoma (PDAC) remains recalcitrant to all forms of cancer treatment and carries a five-year survival rate of only 8%1. Inhibition of oncogenic KRAS (hereafter KRAS*), the earliest lesion in disease development that is present in more than 90% of PDACs, and its signalling surrogates has yielded encouraging preclinical results with experimental agents2-4. However, KRAS*-independent disease recurrence following genetic extinction of Kras* in mouse models anticipates the need for co-extinction strategies5,6. Multiple oncogenic processes are initiated at the cell surface, where KRAS* physically and functionally interacts to direct signalling that is essential for malignant transformation and tumour maintenance. Insights into the complexity of the functional cell-surface-protein repertoire (surfaceome) have been technologically limited until recently and-in the case of PDAC-the genetic control of the function and composition of the PDAC surfaceome in the context of KRAS* signalling remains largely unknown. Here we develop an unbiased, functional target-discovery platform to query KRAS*-dependent changes of the PDAC surfaceome, which reveals syndecan 1 (SDC1, also known as CD138) as a protein that is upregulated at the cell surface by KRAS*. Localization of SDC1 at the cell surface-where it regulates macropinocytosis, an essential metabolic pathway that fuels PDAC cell growth-is essential for disease maintenance and progression. Thus, our study forges a mechanistic link between KRAS* signalling and a targetable molecule driving nutrient salvage pathways in PDAC and validates oncogene-driven surfaceome annotation as a strategy to identify cancer-specific vulnerabilities.


Subject(s)
Carcinoma, Pancreatic Ductal/pathology , Pancreatic Neoplasms/pathology , Pinocytosis , Syndecan-1/metabolism , ADP-Ribosylation Factor 6 , ADP-Ribosylation Factors/metabolism , Animals , Carcinoma, Pancreatic Ductal/genetics , Carcinoma, Pancreatic Ductal/metabolism , Cell Proliferation , Disease Progression , Female , Guanine Nucleotide Exchange Factors/metabolism , Humans , Male , Mice , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/metabolism , Proto-Oncogene Proteins p21(ras)/genetics , Proto-Oncogene Proteins p21(ras)/metabolism , Signal Transduction
13.
Food Nutr Res ; 622018.
Article in English | MEDLINE | ID: mdl-30574053

ABSTRACT

BACKGROUND: Previous studies suggested that probiotics intervention may be one of the methods for preventing and/or treating gastric ulcer. OBJECTIVE: The aim of the study was to compare the preventive effects of a spaceflight mutant Lactobacillus reuteri F-9-35 and its wild type on ethanol-induced gastric injury in rats. DESIGN: Forty rats were randomly allocated into five groups: a normal group (NOR), ethanol group (EtOH), skim milk group (MILK), L. reuteri F-9-35 group (F935) and wild-type group (WT). The NOR and EtOH groups received 1 ml of distilled water by daily gavage for 14 days. The MILK group received 1 ml of skim milk alone, while the F935 and WT groups were administered 1 ml of skim milk containing the mutant and wild type (1 × 1010 colony-forming unit/ml) by daily gavage for 14 days, respectively. Acute gastric injury was induced by absolute alcohol 1 h after the final administration of different treatments, except for the NOR group. RESULTS: Pretreatment with L. reuteri F-9-35, but not milk alone or milk with the L. reuteri wild type, showed significant reduction of ethanol-induced gastric injury, as evidenced by lowering of ulcer index, ulcer area (%), and histological lesion. F-9-35 decreased the levels of lipid peroxidation and myeloperoxidase and increased mucus, glutathione, and nitric oxide levels in gastric tissue. Moreover, F-9-35 inhibited the expression of proinflammatory genes including gastric tumor necrosis factor-α, interleukin-1ß, and cyclooxygenase-2 and decreased the activity of nuclear factor kappa B (NF-κB). CONCLUSION: These findings indicated that L. reuteri F-9-35 pretreatment can attenuate ethanol-induced gastric injury in rats by inhibiting oxidative stress and inflammatory response. Together, L. reuteri F-9-35 has potential preventive efficacy on gastric ulcer.

14.
Soft Matter ; 14(32): 6774-6782, 2018 Aug 15.
Article in English | MEDLINE | ID: mdl-30074601

ABSTRACT

Obtaining nanoscale-ordered structures is important for the development of nanotechnology. We designed and synthesized a series of disk-cube triads containing one hexa-peri-hexabenzocoronene (HBC) and two polyhedral oligomeric silsesquioxane (POSS) moieties, HBC-2POSS. The two POSS units were linked via ester or amide bonds. With the amide linkage used, the hydrogen bonding that was introduced affected the balance between the π-π interaction of HBC cores and crystallization interaction of POSS units. Hierarchically ordered structures were obtained from HBC-2POSS triads owing to the synergistic effect of multiple secondary interactions: π-π interaction, hydrogen bonding, and crystallization interaction. As organic-inorganic hybrid materials, these HBC-2POSS triads are promising candidates for templates <10 nm.

15.
Angew Chem Int Ed Engl ; 57(32): 10132-10136, 2018 Aug 06.
Article in English | MEDLINE | ID: mdl-29883051

ABSTRACT

The self-assembly of a rod-coil amphiphilic block copolymer (ABCP) led to Im3‾ m and Pn3‾ m polymer cubosomes and p6mm polymer hexasomes. This is the first time that these structures are observed in a rod-coil system. By varying the hydrophobic chain length, the initial concentration of the polymer solution, or the solubility parameter of the mixed solvent, head-tail asymmetry is adjusted to control the formation of polymer cubosomes or hexasomes. The formation mechanism of the polymer cubosomes was also studied. This research opens up a new way for further study of the bicontinuous and inverse phases in different ABCP systems.

16.
Cancer Discov ; 6(1): 80-95, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26701088

ABSTRACT

UNLABELLED: The signaling mechanisms between prostate cancer cells and infiltrating immune cells may illuminate novel therapeutic approaches. Here, utilizing a prostate adenocarcinoma model driven by loss of Pten and Smad4, we identify polymorphonuclear myeloid-derived suppressor cells (MDSC) as the major infiltrating immune cell type, and depletion of MDSCs blocks progression. Employing a novel dual reporter prostate cancer model, epithelial and stromal transcriptomic profiling identified CXCL5 as a cancer-secreted chemokine to attract CXCR2-expressing MDSCs, and, correspondingly, pharmacologic inhibition of CXCR2 impeded tumor progression. Integrated analyses identified hyperactivated Hippo-YAP signaling in driving CXCL5 upregulation in cancer cells through the YAP-TEAD complex and promoting MDSC recruitment. Clinicopathologic studies reveal upregulation and activation of YAP1 in a subset of human prostate tumors, and the YAP1 signature is enriched in primary prostate tumor samples with stronger expression of MDSC-relevant genes. Together, YAP-driven MDSC recruitment via heterotypic CXCL5-CXCR2 signaling reveals an effective therapeutic strategy for advanced prostate cancer. SIGNIFICANCE: We demonstrate a critical role of MDSCs in prostate tumor progression and discover a cancer cell nonautonomous function of the Hippo-YAP pathway in regulation of CXCL5, a ligand for CXCR2-expressing MDSCs. Pharmacologic elimination of MDSCs or blocking the heterotypic CXCL5-CXCR2 signaling circuit elicits robust antitumor responses and prolongs survival.


Subject(s)
Chemokine CXCL5/genetics , Myeloid Cells/immunology , PTEN Phosphohydrolase/deficiency , Prostatic Neoplasms/immunology , Smad4 Protein/deficiency , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Animals , Cell Line, Tumor , Chemokine CXCL5/metabolism , Disease Progression , Hippo Signaling Pathway , Humans , Male , Mice , Phosphoproteins/genetics , Phosphoproteins/metabolism , Prostatic Neoplasms/genetics , Prostatic Neoplasms/pathology , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Receptors, Interleukin-8B/genetics , Receptors, Interleukin-8B/metabolism , Signal Transduction , Transcription Factors , YAP-Signaling Proteins
17.
Science ; 341(6146): 651-4, 2013 Aug 09.
Article in English | MEDLINE | ID: mdl-23868920

ABSTRACT

Pluripotent stem cells can be induced from somatic cells, providing an unlimited cell resource, with potential for studying disease and use in regenerative medicine. However, genetic manipulation and technically challenging strategies such as nuclear transfer used in reprogramming limit their clinical applications. Here, we show that pluripotent stem cells can be generated from mouse somatic cells at a frequency up to 0.2% using a combination of seven small-molecule compounds. The chemically induced pluripotent stem cells resemble embryonic stem cells in terms of their gene expression profiles, epigenetic status, and potential for differentiation and germline transmission. By using small molecules, exogenous "master genes" are dispensable for cell fate reprogramming. This chemical reprogramming strategy has potential use in generating functional desirable cell types for clinical applications.


Subject(s)
Cell Engineering/methods , Cellular Reprogramming/drug effects , Fibroblasts/drug effects , Induced Pluripotent Stem Cells/cytology , Small Molecule Libraries/pharmacology , Animals , Cadherins/genetics , Cellular Reprogramming/genetics , Epithelial-Mesenchymal Transition/drug effects , Epithelial-Mesenchymal Transition/genetics , Fibroblasts/cytology , Gene Expression Profiling , Green Fluorescent Proteins/genetics , Induced Pluripotent Stem Cells/metabolism , Mice , Mice, Inbred C57BL , Mice, Inbred ICR , Octamer Transcription Factor-3/genetics , Octamer Transcription Factor-3/metabolism , Promoter Regions, Genetic/drug effects , Small Molecule Libraries/chemistry
18.
Appl Microbiol Biotechnol ; 97(2): 681-92, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22391974

ABSTRACT

A simple preparation process for the monodispersed pH-sensitive core-shell magnetic microspheres was carried out consisting of chitosan self-assembled on magnetic iron oxide nanoparticles. Meanwhile, glucoamylase was immobilized as a model enzyme on this carrier of Fe(3)O(4)/CS microspheres by ionic adsorption. The morphology, inner structure, and high magnetic sensitivity of the resulting magnetic chitosan microspheres were studied, respectively, with a field emission scanning electron microscope (SEM), transmission electron microscope (TEM), FT-IR spectroscopy, thermogravimetric analysis (TGA), and a vibrating sample magnetometer (VSM). Subsequently, the properties of glucoamylase immobilized on the regenerated supports were also investigated by determining storage stability, pH stability, reusability, magnetic response, and regeneration of supports. The results from characterization and determination remarkably indicated that the immobilized glucoamylase obtained presents excellent storage stability, pH stability, reusability, magnetic response, and regeneration of supports. Therefore, this kind of magnetic Fe(3)O(4)/CS microspheres with perfect monodispersity should be an ideal support for enzyme immobilization.


Subject(s)
Chitosan/chemistry , Enzymes, Immobilized/chemistry , Glucan 1,4-alpha-Glucosidase/chemistry , Magnetics , Hydrogen-Ion Concentration , Microscopy, Electron, Scanning , Nanotechnology , Spectroscopy, Fourier Transform Infrared , Thermogravimetry
19.
Cell Res ; 21(1): 196-204, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20956998

ABSTRACT

The introduction of four transcription factors Oct4, Klf4, Sox2 and c-Myc by viral transduction can induce reprogramming of somatic cells into induced pluripotent stem cells (iPSCs), but the use of iPSCs is hindered by the use of viral delivery systems. Chemical-induced reprogramming offers a novel approach to generating iPSCs without any viral vector-based genetic modification. Previous reports showed that several small molecules could replace some of the reprogramming factors although at least two transcription factors, Oct4 and Klf4, are still required to generate iPSCs from mouse embryonic fibroblasts. Here, we identify a specific chemical combination, which is sufficient to permit reprogramming from mouse embryonic and adult fibroblasts in the presence of a single transcription factor, Oct4, within 20 days, replacing Sox2, Klf4 and c-Myc. The iPSCs generated using this treatment resembled mouse embryonic stem cells in terms of global gene expression profile, epigenetic status and pluripotency both in vitro and in vivo. We also found that 8 days of Oct4 induction was sufficient to enable Oct4-induced reprogramming in the presence of the small molecules, which suggests that reprogramming was initiated within the first 8 days and was independent of continuous exogenous Oct4 expression. These discoveries will aid in the future generation of iPSCs without genetic modification, as well as elucidating the molecular mechanisms that underlie the reprogramming process.


Subject(s)
Fibroblasts/cytology , Induced Pluripotent Stem Cells/metabolism , Octamer Transcription Factor-3/metabolism , Animals , Cellular Reprogramming/drug effects , Gene Expression Profiling , Kruppel-Like Factor 4 , Kruppel-Like Transcription Factors/genetics , Kruppel-Like Transcription Factors/metabolism , Mice , Octamer Transcription Factor-3/genetics , Proto-Oncogene Proteins c-myc/genetics , Proto-Oncogene Proteins c-myc/metabolism , Pyridines/pharmacology , Pyrimidines/pharmacology , SOXB1 Transcription Factors/genetics , SOXB1 Transcription Factors/metabolism
20.
Cell Stem Cell ; 3(6): 587-90, 2008 Dec 04.
Article in English | MEDLINE | ID: mdl-19041774
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