Improved Cardiac Function in Postischemic Rats Using an Optimized Cardiac Reprogramming Cocktail Delivered in a Single Novel Adeno-Associated Virus.

Background: Cardiac reprogramming is a technique to directly convert nonmyocytes into myocardial cells using genes or small molecules. This intervention provides functional benefit to the rodent heart when delivered at the time of myocardial infarction or activated transgenically up to 4 weeks after myocardial infarction. Yet, several hurdles have prevented the advancement of cardiac reprogramming for clinical use.

Two-dimensional ultrasonography and CEUS of a case with primary biliary cholangitis and vanishing bile duct syndrome.

Vanishing bile duct syndrome (VBDS) is a pathological concept that refers to the gradual reduction, destruction and disappearance of intrahepatic bile ducts caused by drugs, immunity, malignancy, and infections (including HIV and tuberculosis). Its clinical manifestation is cholestasis. The pathological diagnostic criteria for VBDS are the occurrence of intralobular vanishing bile ducts in more than 50% of 10 or more portal areas.

Retrospective Evaluation of Non-Invasive Assessment Based on Routine Laboratory Markers for Assessing Advanced Liver Fibrosis in Chronic Hepatitis B Patients.

Background: At present, there is a lack of cheap, effective and convenient detection methods for hepatitis B-related liver fibrosis, especially in the developing area.

Aim: To evaluate the non-invasive methods for the significant and advanced fibrosis stage in chronic hepatitis B virus (HBV) patients in basic hospitals and to assess their diagnostic utility.

Methods: The study included 436 consecutive naive HBV individuals who had their livers biopsied.

Context-Specific Transcription Factor Functions Regulate Epigenomic and Transcriptional Dynamics during Cardiac Reprogramming.

Ectopic expression of combinations of transcription factors (TFs) can drive direct lineage conversion, thereby reprogramming a somatic cell's identity. To determine the molecular mechanisms by which Gata4, Mef2c, and Tbx5 (GMT) induce conversion from a cardiac fibroblast toward an induced cardiomyocyte, we performed comprehensive transcriptomic, DNA-occupancy, and epigenomic interrogation throughout the reprogramming process. Integration of these datasets identified new TFs involved in cardiac reprogramming and revealed context-specific roles for GMT, including the ability of Mef2c and Tbx5 to independently promote chromatin remodeling at previously inaccessible sites.

Chemical Enhancement of In Vitro and In Vivo Direct Cardiac Reprogramming.

Background: Reprogramming of cardiac fibroblasts into induced cardiomyocyte-like cells in situ represents a promising strategy for cardiac regeneration. A combination of 3 cardiac transcription factors, Gata4, Mef2c, and Tbx5 (GMT), can convert fibroblasts into induced cardiomyocyte-like cells, albeit with low efficiency in vitro.

Methods: We screened 5500 compounds in primary cardiac fibroblasts to identify the pathways that can be modulated to enhance cardiomyocyte reprogramming.

Effect of biophysical cues on reprogramming to cardiomyocytes.

Reprogramming of fibroblasts to cardiomyocytes offers exciting potential in cell therapy and regenerative medicine, but has low efficiency. We hypothesize that physical cues may positively affect the reprogramming process, and studied the effects of periodic mechanical stretch, substrate stiffness and microgrooved substrate on reprogramming yield. Subjecting reprogramming fibroblasts to periodic mechanical stretch and different substrate stiffness did not improve reprogramming yield.

Peptide-enhanced mRNA transfection in cultured mouse cardiac fibroblasts and direct reprogramming towards cardiomyocyte-like cells.

The treatment of myocardial infarction is a major challenge in medicine due to the inability of heart tissue to regenerate. Direct reprogramming of endogenous cardiac fibroblasts into functional cardiomyocytes via the delivery of transcription factor mRNAs has the potential to regenerate cardiac tissue and to treat heart failure. Even though mRNA delivery to cardiac fibroblasts has the therapeutic potential, mRNA transfection in cardiac fibroblasts has been challenging.

NANOG is multiply phosphorylated and directly modified by ERK2 and CDK1 in vitro.

NANOG is a divergent homeobox protein and a core component of the transcriptional circuitry that sustains pluripotency and self-renewal. Although NANOG has been extensively studied on the transcriptional level, little is known regarding its posttranslational regulation, likely due to its low abundance and challenging physical properties. Here, we identify eleven phosphorylation sites on endogenous human NANOG, nine of which mapped to single amino acids.

Epigenomic analysis of multilineage differentiation of human embryonic stem cells.

Epigenetic mechanisms have been proposed to play crucial roles in mammalian development, but their precise functions are only partially understood. To investigate epigenetic regulation of embryonic development, we differentiated human embryonic stem cells into mesendoderm, neural progenitor cells, trophoblast-like cells, and mesenchymal stem cells and systematically characterized DNA methylation, chromatin modifications, and the transcriptome in each lineage. We found that promoters that are active in early developmental stages tend to be CG rich and mainly engage H3K27me3 upon silencing in nonexpressing lineages.

Instant spectral assignment for advanced decision tree-driven mass spectrometry.

We have developed and implemented a sequence identification algorithm (inSeq) that processes tandem mass spectra in real-time using the mass spectrometer's (MS) onboard processors. The inSeq algorithm relies on accurate mass tandem MS data for swift spectral matching with high accuracy. The instant spectral processing technology takes ∼16 ms to execute and provides information to enable autonomous, real-time decision making by the MS system.

Phosphorylation regulates human OCT4.

The transcription factor OCT4 is fundamental to maintaining pluripotency and self-renewal. To better understand protein-level regulation of OCT4, we applied liquid chromatography-MS to identify 14 localized sites of phosphorylation, 11 of which were previously unknown. Functional analysis of two sites, T234 and S235, suggested that phosphorylation within the homeobox region of OCT4 negatively regulates its activity by interrupting sequence-specific DNA binding.

Thermal stability of fibroblast growth factor protein is a determinant factor in regulating self-renewal, differentiation, and reprogramming in human pluripotent stem cells.

Fibroblast growth factor (FGF), transforming growth factor (TGF)/Nodal, and Insulin/insulin-like growth factor (IGF) signaling pathways are sufficient to maintain human embryonic stem cells (ESCs) and induced pluripotent stem cells in a proliferative, undifferentiated state. Here, we show that only a few FGF family members (FGF2, FGF4, FGF6, and FGF9) are able to sustain strong extracellular-signal-regulated kinase (ERK) phosphorylation and NANOG expression levels in human ESCs. Surprisingly, FGF1, which is reported to target the same set of receptors as FGF2, fails to sustain ERK phosphorylation and NANOG expression under standard culture conditions.

Dynamic chromatin states in human ES cells reveal potential regulatory sequences and genes involved in pluripotency.

Pluripotency, the ability of a cell to differentiate and give rise to all embryonic lineages, defines a small number of mammalian cell types such as embryonic stem (ES) cells. While it has been generally held that pluripotency is the product of a transcriptional regulatory network that activates and maintains the expression of key stem cell genes, accumulating evidence is pointing to a critical role for epigenetic processes in establishing and safeguarding the pluripotency of ES cells, as well as maintaining the identity of differentiated cell types. In order to better understand the role of epigenetic mechanisms in pluripotency, we have examined the dynamics of chromatin modifications genome-wide in human ES cells (hESCs) undergoing differentiation into a mesendodermal lineage.

FGF2 sustains NANOG and switches the outcome of BMP4-induced human embryonic stem cell differentiation.

Here, we show that as human embryonic stem cells (ESCs) exit the pluripotent state, NANOG can play a key role in determining lineage outcome. It has previously been reported that BMPs induce differentiation of human ESCs into extraembryonic lineages. Here, we find that FGF2, acting through the MEK-ERK pathway, switches BMP4-induced human ESC differentiation outcome to mesendoderm, characterized by the uniform expression of T (brachyury) and other primitive streak markers.