Reprogramming of fibroblasts into expandable cardiovascular progenitor cells via small molecules in xeno-free conditions.

A major hurdle in cardiac cell therapy is the lack of a bona fide autologous stem-cell type that can be expanded long-term and has authentic cardiovascular differentiation potential. Here we report that a proliferative cell population with robust cardiovascular differentiation potential can be generated from mouse or human fibroblasts via a combination of six small molecules. These chemically induced cardiovascular progenitor cells (ciCPCs) self-renew long-term in fully chemically defined and xeno-free conditions, with faithful preservation of the CPC phenotype and of cardiovascular differentiation capacity in vitro and in vivo. Transplantation of ciCPCs into infarcted mouse hearts improved animal survival and cardiac function up to 13 weeks post-infarction. Mechanistically, activated fibroblasts revert to a plastic state permissive to cardiogenic signals, enabling their reprogramming into ciCPCs. Expanded autologous cardiovascular cells may find uses in drug discovery, disease modelling and cardiac cell therapy.

Facile construction of g-C3N4/ZnIn2S4 nanocomposites for enhance Cr(VI) photocatalytic reduction.

Hexavalent chromium (Cr(VI)) is the nether-most toxic environmental pollutants. In this work, g-C3N4/ZnIn2S4 photocatalyst was constructed to investigate their potential application for economical visible-light photocatalytic reduction of Cr(VI). Photocatalysts phase and microstructure were analyzed by XRD, SEM and TEM techniques. Elements were confirmed by EDS and XPS techniques. Optical properties were revealed by DRS and emission spectra. The generation and activeness of photogenerated electron-hole pairs were revealed by the emission spectra, photocurrent response and Nyquist plots. The result is perfectly displayed that g-C3N4/ZnIn2S4 has potential application in photocatalysis field and g-C3N4/ZnIn2S4 has higher photocatalytic occupation than that of g-C3N4 and ZnIn2S4.

Bi/BiVO4/NiFe-LDH heterostructures with enhanced photoelectrochemical performance for streptomycin detection.

Streptomycin (STR) plays an essential role in bacterial infection treatments. Selectivity and sensitivity of photoelectrochemical (PEC) sensors are the two most important parameters, which can be measured using the photosensitivity of its active material. We prepared a novel PEC sensor to detect STR using Bi/BiVO4/LDH (layered double hydroxides) heterostructures as an active material, which is photoactive in the visible light wavelength range. The simultaneous presence of LDH and Bi/BiVO4 enhanced the material photocurrent response, which was linear to the STR concentrations in the 0.01-500 nmol/L range. The STR detection limit by this sensor was 0.0042 nmol/L. Our novel PEC-based sensing strategy includes using an ultra-sensitive and highly selective sensor for STR detection. Additionally, the two-pot synthesis of Bi/BiVO4/LDH developed in this work is environmentally friendly.

Pten Regulates Cardiomyocyte Differentiation by Modulating Non-CG Methylation via Dnmt3.

The regulation of cardiomyocyte differentiation is a fundamental aspect of cardiac development and regenerative medicine. PTEN plays important roles during embryonic development. However, its role in cardiomyocyte differentiation remains unknown. In this study, a low-cost protocol for cardiomyocyte differentiation from mouse embryonic stem cells (ESCs) is presented and it is shown that Pten deletion potently suppresses cardiomyocyte differentiation. Transcriptome analysis shows that the expression of a series of cardiomyocyte marker genes is downregulated in Pten-/- cardiomyocytes. Pten ablation induces Dnmt3b expression via the AKT/FoxO3a pathway and regulates the expression of a series of imprinted genes, including Igf2. Double knockout of Dnmt3l and Dnmt3b rescues the deficiency of cardiomyocyte differentiation of Pten-/- ESCs. The DNA methylomes from wild-type and Pten-/- embryoid bodies and cardiomyocytes are analyzed by whole-genome bisulfite sequencing. Pten deletion significantly promotes the non-CG (CHG and CHH) methylation levels of genomic DNA during cardiomyocyte differentiation, and the non-CG methylation levels of cardiomyocyte genes and Igf2 are increased in Pten-/- cardiomyocytes. Igf2 or Igf1r deletion also suppresses cardiomyocyte differentiation through the MAPK/ERK signaling pathway, and IGF2 supplementation partially rescues the cardiomyocyte differentiation. Finally, Pten conditional knockout mice are generated and the role of PTEN in cardiomyocyte differentiation is verified in vivo.

Targeted RNA N6 -Methyladenosine Demethylation Controls Cell Fate Transition in Human Pluripotent Stem Cells.

Deficiency of the N6 -methyladenosine (m6 A) methyltransferase complex results in global reduction of m6 A abundance and defective cell development in embryonic stem cells (ESCs). However, it's unclear whether regional m6 A methylation affects cell fate decisions due to the inability to modulate individual m6 A modification in ESCs with precise temporal control. Here, a targeted RNA m6 A erasure (TRME) system is developed to achieve site-specific demethylation of RNAs in human ESCs (hESCs). TRME, in which a stably transfected, doxycycline-inducible dCas13a is fused to the catalytic domain of ALKBH5, can precisely and reversibly demethylate the targeted m6 A site of mRNA and increase mRNA stability with limited off-target effects. It is further demonstrated that temporal m6 A erasure on a single site of SOX2 is sufficient to control the differentiation of hESCs. This study provides a versatile toolbox to reveal the function of individual m6 A modification in hESCs, enabling cell fate control studies at the epitranscriptional level.

Dual Thermo- and Photo-Responsive Micelles Based on Azobenzene-Containing Random Copolymer.

Amphiphilic random copolymer poly(methacrylamido-azobenzene)-ran-poly(2-hydroxyethylacrylate) (PMAAAB-ran-PHEA) was synthesized via hydrolysis of poly(methacrylamido-azobenzene)-ran-poly[2-((2'-tetrahydropyranyl)oxy)ethylacrylate] (PMAAAB-ran-P(THP-HEA)), which was prepared by conventional radical polymerization. PMAAAB-ran-PHEA micelles were then prepared via dialysis method against water with DMF as solvent. The structure, morphology, size, and low critical solution temperature (LCST) of PMAAAB-ran-PHEA and its micelles were determined by 1H-NMR, GPC, TEM, and DLS. The thermo- and photo-responsive behaviors of the resulting polymer micelles were investigated with Nile red as a fluorescence probe. The results showed that PMAAAB-ran-PHEA micelles were porous or bowl-shaped and its size was 135-150 nm, and its LCST was 55 °C when FMAAAB of the random copolymer was 0.5351; the hydrophobicity of the micellar core was changed reversibly under the irradiation of UV light and visible light without release of Nile red or disruption of micelles; the size and solubilization capacity of the micelles were dependent on temperature, and Nile red would migrate for many times between the water phase and the micelles, and finally increasingly accumulated during the repeated heating and cooling processes.

Bacteriorhodopsin-Inspired Light-Driven Artificial Molecule Motors for Transmembrane Mass Transportation.

In nature, biological machines and motors can selectively transport cargoes across the lipid membranes to efficiently perform various physiological functions via ion channels or ion pumps. It is interesting and challengeable to develop artificial motors and machines of nanodimensions to controllably regulate mass transport in compartmentalized systems. In this work, we show a system of artificial molecular motors that uses light energy to perform transmembrane molecule transport through synthetical nanochannels. After functionalizing the polymer nanochannels with azobenzene derivatives, these nanomachines exhibit autonomous selective transport behavior over a long distance upon simultaneous irradiation with UV (365 nm) and visible (430 nm) light. With new strategies or suitable materials for directed molecular movement, such device can be regarded as a precursor of artificial light-driven molecular pumps.

Light- and Electric-Field-Controlled Wetting Behavior in Nanochannels for Regulating Nanoconfined Mass Transport.

Water wetting behavior in nanoconfined environments plays an important role in mass transport and signal transmission of organisms. It is valuable and challenging to investigate how water behaves in such a nanometer-scale with external stimuli, in particular with electric field and light. Unfortunately, the mechanism of hydrophobic reaction inside the nanospaces is still obscure and lacks experimental support for the current electric-field- or photoresponsive nanochannels which suffer from fragility or monofunctionality. Here, we design functionalized hydrophobic nanopores to regulate ion transport by light and electric field using azobenzene-derivatives-modified polymer nanochannels. With these addressable features, we can control the pore surface wetting behavior to switch the nanochannels between nonconducting and conducting states. Furthermore, we found these hydrophobic nanochannels are rough with a contact angle of 67.3°, making them extremely different from the familiar ones with a smooth pore surface and larger contact angles (>90°). These findings point to new opportunities for studying and manipulating water behavior in nanoconfined environments.

Using low-risk factors to generate non-integrated human induced pluripotent stem cells from urine-derived cells.

BACKGROUND: Because the lack of an induced pluripotent stem cell (iPSC) induction system with optimal safety and efficiency limits the application of these cells, development of such a system is important. METHODS: To create such an induction system, we screened a variety of reprogrammed plasmid combinations and multiple compounds and then verified the system's feasibility using urine cells from different individuals. We also compared large-scale iPSC chromosomal variations and expression of genes associated with genomic stability between this system and the traditional episomal system using karyotype and quantitative reverse transcription polymerase chain reaction analyses. RESULTS: We developed a high-efficiency episomal system, the 6F/BM1-4C system, lacking tumorigenic factors for human urine-derived cell (hUC) reprogramming. This system includes six low-risk factors (6F), Oct4, Glis1, Klf4, Sox2, L-Myc, and the miR-302 cluster. Transfected hUCs were treated with four compounds (4C), inhibitor of lysine-demethylase1, methyl ethyl ketone, glycogen synthase kinase 3 beta, and histone deacetylase, within a short time period. Comparative analysis revealed significantly decreased chromosomal variation in iPSCs and significantly increased Sirt1 expression compared with iPSCs induced using the traditional episomal system. CONCLUSION: The 6F/BM1-4C system effectively induces reprogramming of urine cells in samples obtained from different individuals. iPSCs induced using the 6F/BM1-4C system are more stable at the cytogenetic level and have potential value for clinical application.

Sequential Recognition of Zinc and Pyrophosphate Ions in a Terpyridine-Functionalized Single Nanochannel.

A highly selective recognition system for zinc(II) and pyrophosphate ions is constructed using a single conical nanochannel covalently functionalized with N'-{4-[(2,2':6',2''-terpyridine)-4-yl]benzyl}ethane-1,2-diamine (TPYD). The immobilized TPYD acts as a specific coordination site for Zn2+ to form TPYD-Zn2+ complexes in preference over other metal ions, and subsequently, the resulting Zn2+ -coordinated nanochannel can be used as a selective recognition element for the pyrophosphate ion based on the coordination reaction between hydroxyl oxygen atoms of pyrophosphate and Zn2+ . Ion recognition is monitored by measuring the current-voltage curves of the solutions. The ionic current of the TPYD-functionalized system at -2.0 V undergoes a clear decrease after exposure to Zn2+ ions and is followed with an obvious increase after subsequent treatment with a pyrophosphate solution. The change of ionic current can be primarily attributed to the variation of charge density of the nanochannel. This functionalized single nanochannel might provide a simple and universal means to recognize other targets by modifying different functional molecules onto the inner surfaces of nanochannels.

miR-411 contributes the cell proliferation of lung cancer by targeting FOXO1.

Lung cancer is the leading cause of cancer deaths worldwide; the study of microRNAs gives new hope for lung cancer treatment. miR-411 has been demonstrated to be an independent prognostic factor for lung adenocarcinoma, but the role and regulatory mechanism are largely unknown. In the present study, we found miR-411 was overexpressed in the lung cancer cells; overexpression of miR-411 promoted anchorage-dependent and anchorage-independent growths of lung cancer, while miR-411 knockdown reduced this effect. Further study showed forkhead box O1 (FOXO1) was a target of miR-411. Overexpression of miR-411 suppressed the expression of FOXO1; the effect of suppression was abrogated when the mutation occurred in the 3'UTR of FOXO1. Knockdown of FOXO1 in cells which miR-411 was inhibited recapitulated the phenotype of miR-411 overexpression. Taken together, our study revealed miR-411 promoted cell proliferation of lung cancer by targeting tumor suppressor gene FOXO1 and miR-411 might be a potential target for lung cancer therapy.

The roles of ncRNAs and histone-modifiers in regulating breast cancer stem cells.

Cancer stem cells (CSCs), a subpopulation of cancer cells with ability of initiating tumorigenesis, exist in many kinds of tumors including breast cancer. Cancer stem cells contribute to treatment resistance and relapse. Conventional treatments only kill differentiated cancer cells, but spare CSCs. Combining conventional treatments with therapeutic drugs targeting to CSCs will eradicate cancer cells more efficiently. Studying the molecular mechanisms of CSCs regulation is essential for developing new therapeutic strategies. Growing evidences showed CSCs are regulated by non-coding RNA (ncRNA) including microRNAs and long non-coding RNAs (lncRNAs), and histone-modifiers, such as let-7, miR-93, miR-100, HOTAIR, Bmi-1 and EZH2. Herein we review the roles of microRNAs, lncRNAs and histone-modifiers especially Polycomb family proteins in regulating breast cancer stem cells (BCSCs).

Role of microRNA221 in regulating normal mammary epithelial hierarchy and breast cancer stem-like cells.

Increasing evidence suggests that lineage specific subpopulations and stem-like cells exist in normal and malignant breast tissues. Epigenetic mechanisms maintaining this hierarchical homeostasis remain to be investigated. In this study, we found the level of microRNA221 (miR-221) was higher in stem-like and myoepithelial cells than in luminal cells isolated from normal and malignant breast tissue. In normal breast cells, over-expression of miR-221 generated more myoepithelial cells whereas knock-down of miR-221 increased luminal cells. Over-expression of miR-221 stimulated stem-like cells in luminal type of cancer and the miR-221 level was correlated with clinical outcome in breast cancer patients. Epithelial-mesenchymal transition (EMT) was induced by overexpression of miR-221 in normal and breast cancer cells. The EMT related gene ATXN1 was found to be a miR-221 target gene regulating breast cell hierarchy. In conclusion, we propose that miR-221 contributes to lineage homeostasis of normal and malignant breast epithelium.

Modeling of hemophilia A using patient-specific induced pluripotent stem cells derived from urine cells.

AIMS: Hemophilia A (HA) is a severe, congenital bleeding disorder caused by the deficiency of clotting factor VIII (FVIII). For years, traditional laboratory animals have been used to study HA and its therapies, although animal models may not entirely mirror the human pathophysiology. Human induced pluripotent stem cells (iPSCs) can undergo unlimited self-renewal and differentiate into all cell types. This study aims to generate hemophilia A (HA) patient-specific iPSCs that differentiate into disease-affected hepatocyte cells. These hepatocytes are potentially useful for in vitro disease modeling and provide an applicable cell source for autologous cell therapy after genetic correction. MAIN METHODS: In this study, we mainly generated iPSCs from urine collected from HA patients with integration-free episomal vectors PEP4-EO2S-ET2K containing human genes OCT4, SOX2, SV40LT and KLF4, and differentiated these iPSCs into hepatocyte-like cells. We further identified the genetic phenotype of the FVIII genes and the FVIII activity in the patient-specific iPSC derived hepatic cells. KEY FINDINGS: HA patient-specific iPSCs (HA-iPSCs) exhibited typical pluripotent properties evident by immunostaining, in vitro assays and in vivo assays. Importantly, we showed that HA-iPSCs could differentiate into functional hepatocyte-like cells and the HA-iPSC-derived hepatocytes failed to produce FVIII, but otherwise functioned normally, recapitulating the phenotype of HA disease in vitro. SIGNIFICANCE: HA-iPSCs, particular those generated from the urine using a non-viral approach, provide an efficient way for modeling HA in vitro. Furthermore, HA-iPSCs and their derivatives serve as an invaluable cell source that can be used for gene and cell therapy in regenerative medicine.