Preparation and performance evaluation of fluorescent nanofluid for oil displacement.

Oil displacement agent technology is an attractive technique for improving oil recovery efficiency, as it not only enhances oil recovery efficiency and extends oilfield lifespan, but also helps reduce environmental impact and improve the precision of oilfield management. However, the application of traditional oil displacement agents in oilfield development is limited by poor local fluidity and difficulty in monitoring their effectiveness. To improve oil displacement efficiency and achieve more accurate process monitoring, this paper designs an oil displacement agent that has both oil displacement and tracer functions.

Gastruloids enable modeling of the earliest stages of human cardiac and hepatic vascularization.

Although model organisms have provided insight into the earliest stages of cardiac and hepatic vascularization, we know very little about this process in humans because of ethical restrictions and the technical difficulty of obtaining embryos during very early development. In this study, we demonstrate that micropatterned human pluripotent stem cell-derived gastruloids enable in vitro modeling of the earliest stages of vascularization. We identify a combination of vascular-inducing factors that give rise to cardiac vascularized organoids with a spatially organized and branched vascular network.

Double knockdown of prolyl hydroxylase and factor-inhibiting hypoxia-inducible factor with nonviral minicircle gene therapy enhances stem cell mobilization and angiogenesis after myocardial infarction.

Background: Under normoxic conditions, hypoxia-inducible factor (HIF)-1α is rapidly degraded by 2 hydroxylases: prolyl hydroxylase (PHD) and factor-inhibiting HIF-1 (FIH). Because HIF-1α mediates the cardioprotective response to ischemic injury, its upregulation may be an effective therapeutic option for ischemic heart failure.

Methods And Results: PHD and FIH were cloned from mouse embryonic stem cells.

Novel microRNA prosurvival cocktail for improving engraftment and function of cardiac progenitor cell transplantation.

Background: Although stem cell therapy has provided a promising treatment for myocardial infarction, the low survival of the transplanted cells in the infarcted myocardium is possibly a primary reason for failure of long-term improvement. Therefore, the development of novel prosurvival strategies to boost stem cell survival will be of significant benefit to this field.

Methods And Results: Cardiac progenitor cells (CPCs) were isolated from transgenic mice, which constitutively express firefly luciferase and green fluorescent protein.

Generation of adult human induced pluripotent stem cells using nonviral minicircle DNA vectors.

Human induced pluripotent stem cells (hiPSCs) derived from patient samples have tremendous potential for innovative approaches to disease pathology investigation and regenerative medicine therapies. However, most hiPSC derivation techniques use integrating viruses, which may leave residual transgene sequences as part of the host genome, thereby unpredictably altering cell phenotype in downstream applications. In this study, we describe a protocol for hiPSC derivation by transfection of a simple, nonviral minicircle DNA construct into human adipose stromal cells (hASCs).

MicroRNA-210 as a novel therapy for treatment of ischemic heart disease.

Background: MicroRNAs are involved in various critical functions, including the regulation of cellular differentiation, proliferation, angiogenesis, and apoptosis. We hypothesize that microRNA-210 can rescue cardiac function after myocardial infarction by upregulation of angiogenesis and inhibition of cellular apoptosis in the heart.

Methods And Results: Using microRNA microarrays, we first showed that microRNA-210 was highly expressed in live mouse HL-1 cardiomyocytes compared with apoptotic cells after 48 hours of hypoxia exposure.

Dynamic microRNA expression programs during cardiac differentiation of human embryonic stem cells: role for miR-499.

Background: MicroRNAs (miRNAs) are a newly discovered endogenous class of small, noncoding RNAs that play important posttranscriptional regulatory roles by targeting messenger RNAs for cleavage or translational repression. Human embryonic stem cells are known to express miRNAs that are often undetectable in adult organs, and a growing body of evidence has implicated miRNAs as important arbiters of heart development and disease.

Methods And Results: To better understand the transition between the human embryonic and cardiac "miRNA-omes," we report here the first miRNA profiling study of cardiomyocytes derived from human embryonic stem cells.

A nonviral minicircle vector for deriving human iPS cells.

Owing to the risk of insertional mutagenesis, viral transduction has been increasingly replaced by nonviral methods to generate induced pluripotent stem cells (iPSCs). We report the use of 'minicircle' DNA, a vector type that is free of bacterial DNA and capable of high expression in cells, for this purpose. Here we use a single minicircle vector to generate transgene-free iPSCs from adult human adipose stem cells.

Functional and transcriptional characterization of human embryonic stem cell-derived endothelial cells for treatment of myocardial infarction.

Background: Differentiation of human embryonic stem cells into endothelial cells (hESC-ECs) has the potential to provide an unlimited source of cells for novel transplantation therapies of ischemic diseases by supporting angiogenesis and vasculogenesis. However, the endothelial differentiation efficiency of the conventional embryoid body (EB) method is low while the 2-dimensional method of co-culturing with mouse embryonic fibroblasts (MEFs) require animal product, both of which can limit the future clinical application of hESC-ECs. Moreover, to fully understand the beneficial effects of stem cell therapy, investigators must be able to track the functional biology and physiology of transplanted cells in living subjects over time.

Feeder-free derivation of induced pluripotent stem cells from adult human adipose stem cells.

Ectopic expression of transcription factors can reprogram somatic cells to a pluripotent state. However, most of the studies used skin fibroblasts as the starting population for reprogramming, which usually take weeks for expansion from a single biopsy. We show here that induced pluripotent stem (iPS) cells can be generated from adult human adipose stem cells (hASCs) freshly isolated from patients.

Novel minicircle vector for gene therapy in murine myocardial infarction.

Background: Conventional plasmids for gene therapy produce low-level and short-term gene expression. In this study, we develop a novel nonviral vector that robustly and persistently expresses the hypoxia-inducible factor-1 alpha (HIF-1alpha) therapeutic gene in the heart, leading to functional benefits after myocardial infarction.

Methods And Results: We first created minicircles (MC) carrying double-fusion reporter gene consisting of firefly luciferase and enhanced green fluorescent protein (Fluc-eGFP) for noninvasive measurement of transfection efficiency.

MicroRNA profiling of human-induced pluripotent stem cells.

MicroRNAs (miRNAs) are a newly discovered endogenous class of small noncoding RNAs that play important posttranscriptional regulatory roles by targeting mRNAs for cleavage or translational repression. Accumulating evidence now supports the importance of miRNAs for human embryonic stem cell (hESC) self-renewal, pluripotency, and differentiation. However, with respect to induced pluripotent stem cells (iPSC), in which embryonic-like cells are reprogrammed from adult cells using defined factors, the role of miRNAs during reprogramming has not been well-characterized.

Short hairpin RNA interference therapy for ischemic heart disease.

Background: During hypoxia, upregulation of hypoxia inducible factor-1 alpha transcriptional factor can activate several downstream angiogenic genes. However, hypoxia inducible factor-1 alpha is naturally degraded by prolyl hydroxylase-2 (PHD2) protein. Here we hypothesize that short hairpin RNA (shRNA) interference therapy targeting PHD2 can be used for treatment of myocardial ischemia and this process can be followed noninvasively by molecular imaging.

Identification of zebrafish LPTS: a gene with similarities to human LPTS/PinX1 that inhibits telomerase activity.

Human LPTS/PinX1 is a newly identified telomerase inhibitory protein. Overexpression of the LPTS/PinX1 gene suppresses telomerase activity, results in shortened telomeres. To investigate the role of the LPTS gene in zebrafish, we cloned the homologous gene, zLPTS, which encodes a protein of 355 amino acids.

A strategy for constructing and verifying short hairpin RNA expression vectors.

The application of RNA interference (RNAi) to study gene function is now commonplace in a variety of biological systems. Producing short hairpin RNA (shRNA) by DNA vectors is one popular strategy for RNAi applications. Here, we describe a one-step PCR method, termed reverse PCR, for constructing shRNA expression vectors.

Transactivated minimal E1b promoter is capable of driving the expression of short hairpin RNA.

The strategy that transcribes short hairpin RNAs (shRNAs) by RNA polymerase II promoters is expected to present flexible approaches for regulating the patterns of shRNA expression. The capacity of generating shRNA by a modified adenovirus RNA polymerase II E1b promoter was studied. This 49bp promoter consists of a TATA-box and an initiation element.

Fast screening target sites for RNA interference using a cell-free system.

A fast and simple procedure to screen target sites for RNA interference by using RNA in a cell-free system of Hela cells, and then evaluating the efficiency by Northern blotting, is described. This procedure produces results with an identical reliability compared to those described previously but which are more time-consuming than this present method.