The status of MAPK cascades contributes to the induction and activation of Gata4 and Nkx2.5 during the stepwise process of cardiac differentiation

Exosomes derived from induced cardiopulmonary progenitor cells alleviate acute lung injury in mice

Cardiopulmonary progenitor cells (CPPs) constitute a minor subpopulation of cells that are commonly associated with heart and lung morphogenesis during embryonic development but completely subside after birth. This fact offers the possibility for the treatment of pulmonary heart disease (PHD), in which the lung and heart are both damaged. A reliable source of CPPs is urgently needed. In this study, we reprogrammed human cardiac fibroblasts (HCFs) into CPP-like cells (or induced CPPs, iCPPs) and evaluated the therapeutic potential of iCPP-derived exosomes for acute lung injury (ALI). iCPPs were created in passage 3 primary HCFs by overexpressing GLI1, WNT2, ISL1 and TBX5 (GWIT). Exosomes were isolated from the culture medium of passage 6-8 GWIT-iCPPs. A mouse ALI model was established by intratracheal instillation of LPS. Four hours after LPS instillation, ALI mice were treated with GWIT-iCPP-derived exosomes (5 × 109, 5 × 1010 particles/mL) via intratracheal instillation. We showed that GWIT-iCPPs could differentiate into cell lineages, such as cardiomyocyte-like cells, endothelial cells, smooth muscle cells and alveolar epithelial cells, in vitro. Transcription analysis revealed that GWIT-iCPPs have potential for heart and lung development. Intratracheal instillation of iCPP-derived exosomes dose-dependently alleviated LPS-induced ALI in mice by attenuating lung inflammation, promoting endothelial function and restoring capillary endothelial cells and the epithelial cells barrier. This study provides a potential new method for the prevention and treatment of cardiopulmonary injury, especially lung injury, and provides a new cell model for drug screening.

Cripto Is Targeted by miR-1a-3p in a Mouse Model of Heart Development

During cardiac differentiation, numerous factors contribute to the development of the heart. Understanding the molecular mechanisms underlying cardiac development will help combat cardiovascular disorders, among the leading causes of morbidity and mortality worldwide. Among the main mechanisms, we indeed find Cripto. Cripto is found in both the syncytiotrophoblast of ampullary pregnancies and the inner cell mass along the primitive streak as the second epithelial-mesenchymal transformation event occurs to form the mesoderm and the developing myocardium. At the same time, it is now known that cardiac signaling pathways are intimately intertwined with the expression of myomiRNAs, including miR-1. This miR-1 is one of the muscle-specific miRs; aberrant expression of miR-1 plays an essential role in cardiac diseases. Given this scenario, our study aimed to evaluate the inverse correlation between Cripto and miR-1 during heart development. We used in vitro models of the heart, represented by embryoid bodies (EBs) and embryonic carcinoma cell lines derived from an embryo-derived teratocarcinoma in mice (P19 cells), respectively. First, through a luciferase assay, we demonstrated that Cripto is a target of miR-1. Following this result, we observed that as the days of differentiation increased, the Cripto gene expression decreased, while the level of miR-1 increased; furthermore, after silencing miR-1 in P19 cells, there was an increase in Cripto expression. Moreover, inducing damage with a cobra cardiotoxin (CTX) in post-differentiation cells, we noted a decreased miR-1 expression and increased Cripto. Finally, in mouse cardiac biopsies, we observed by monitoring gene expression the distribution of Cripto and miR-1 in the right and left ventricles. These results allowed us to detect an inverse correlation between miR-1 and Cripto that could represent a new pharmacological target for identifying new therapies.

Cardiac Transcription Regulators Differentiate Human Umbilical Cord Mesenchymal Stem Cells into Cardiac Cells

Stem cell-based therapy presents an attractive alternative to conventional therapies for degenerative diseases. Numerous studies have investigated the capability of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) to contribute to the regeneration of cardiomyocytes, and the results have encouraged further basic and clinical studies on the MSC-based treatment of cardiomyopathies. This study aimed to determine the potential of cardiomyogenic transcription factors in differentiating hUC-MSCs into cardiac-like cells in vitro. MSCs were isolated from umbilical cord tissue and were transduced with the transcription factor genes, GATA-4 and Nkx 2.5, via infection with lentiviruses, to promote differentiation into the cardiomyogenic lineage. Gene and protein expression were analysed with qPCR and immunocytochemical staining. After transduction, differentiated cardiac-like cells showed significant expression of cardiac genes and proteins, namely GATA-4, Nkx-2.5, cardiac troponin I (cTnI) and myosin heavy chain (MHC). The cardiomyogenic-induced group significantly overexpressed cardiac-specific genes (GATA-4, Nkx-2.5, cTnI, MHC, α-actinin and Wnt2). Expression of the calcium channel gene was also significantly increased, while the sodium channel gene was downregulated in the transduced hUC-MSCs, as compared to non-transduced cells. The results suggest that GATA-4 and Nkx-2.5 interact synergistically in the activation of downstream cardiac transcription factors, demonstrating the functional convergence of hUC-MSC differentiation into cardiac-like cells. These findings could potentially be utilised in the efficient production of cardiac-like cells from stem cells; these cardiac-like cells could then be used in various applications, such as for in vivo implantation in infarcted myocardium, and for drug screening in toxicity testing.

Relationship between maternal heavy metal exposure and congenital heart defects: a systematic review and meta-analysis

Congenital heart defects (CHDs) are one of the major causes of death in infants and young children, and heavy metal exposure during pregnancy is one of the possible risk factors. However, the effect of heavy metal exposure on CHDs is still controversial. We searched English (PubMed, Web of Science) and Chinese (CNKI and WanFang database) databases for relevant articles. The summarized effect sizes and 95% confidence intervals (CIs) were calculated by pooling estimates using the random-effects model. Egger's test was used to estimate publication bias. Heterogeneity among studies was indicated by p-values and I². Finally, we conducted subgroup analyses to elucidate the causes of heterogeneity. Thirteen studies were included in this meta-analysis. A positive association between maternal exposure to heavy metals and CHDs was found. Pooling odds ratios (ORs) for arsenic, cadmium, mercury, and lead were 2.12, 1.30, 1.22, and 2.30, respectively for total CHDs. Regarding CHD subtypes, arsenic was associated with an increased risk of septal defects (OR: 1.82), barium with left ventricular outflow tract obstruction (LVOTO) (OR: 1.15) and septal defects (OR: 1.21), and lead with conotruncal defects (OR: 2.34) and LVOTO (OR: 1.93). A heterogeneous relationship was found between studies using different methods of measurement, which were mainly due to differences in actual exposure levels to heavy metals. This meta-analysis suggests significant associations between arsenic, cadmium, mercury, and lead exposure during pregnancy and an increased risk of specific CHDs in offspring. These findings underscore the importance of heavy metal exposure during pregnancy in the risk of CHDs in offspring.

Engineering Multifunctional Hydrogel-Integrated 3D Printed Bioactive Prosthetic Interfaces for Osteoporotic Osseointegration

3D printed porous titanium alloy implants is an advanced orthopedic material for joint replacement. However, the high risk of aseptic loosening and periprosthetic infection is difficult to avoid, and the declined autophagy of osteoporosis-derived bone marrow mesenchymal stem cells (OP-BMSCs) further severely impairs the osseointegration under the osteoporotic circumstance. It is thus becoming urgently significant to develop orthopedic materials with autophagy regulation and antibacterial bioactivity. In this regard, a novel class of multifunctional hydrogel-integrated 3D printed bioactive prosthetic interfaces is engineered for in situ osseointegration in osteoporosis. The hydrogel is fabricated from the dynamic crosslinking of synthetic polymers, natural polymers, and silver nanowires to deliver autophagy-regulated rapamycin. Therefore, the resultant soft material exhibits antibacterial ability, biocompatibility, degradability, conductive, self-healing, and stimuli-responsive abilities. In vitro experiments demonstrate that the hydrogel-integrated 3D printed bioactive prosthetic interfaces can restore the declined cellular activities of OP-BMSCs by upregulating the autophagy level and show excellent antibacterial activity against S. aureus and MRSA. More remarkably, the multifunctional 3D printed bioactive prosthetic interfaces significantly improve osseointegration and inhibit infection in osteoporotic environment in vivo. This study provides an efficient strategy to develop novel prosthetic interfaces to reduce complications after arthroplasty for patients with osteoporosis.

Icariin Promotes In Vitro Cardiomyocyte Proliferation and Differentiation in Human Bone Marrow-Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are the excellent candidates in myocardial regeneration given their easy accessibility, low immunogenicity and high potential for cardiomyocyte differentiation. This work focused on investigating the role of icariin, a main active component of the Traditional Chinese herb epimedium, in human bone marrow-derived MSCs (BMSCs) proliferation and differentiation into cardiomyocytes In Vitro. Human BMSCs were cultivated In Vitro, and MTT assay was conducted to measure their proliferation. On this basis, we selected the optimal icariin dose for promoting the proliferation to induce cardiomyocyte differentiation of MSCs, which were pretreated with or without 5-azacytidine (5-Aza). Cardiac-specific cardiac troponin I (cTnI) and connexin 43 (Cx43)-positive cells were detected by immunofluorescent staining. The differentiation ratio of MSCs was examined by flow cytometry. This study measured early cardiac transcription factors (TFs) Nkx2.5 and GATA4 levels through RT-PCR and Western blotting (WB). As a result, icariin increased MSC proliferation dependent on its dose, and the optimal dose was determined to be 80 μg/l. Furthermore, MSCs showed minimal cardiomyogenic differentiation when induced by icariin alone as confirmed by the expression of cardiac-related markers. Moreover, a synergic interaction was observed when icariin and 5-Aza cooperated to induce cardiomyocyte differentiation of MSCs. In conclusion, Icariin stimulates proliferation and facilitates cardiomyocyte differentiation of MSCs In Vitro and may be potentially used as a new method for enhancing the MSCs efficacy in cardiovascular disease.

Activation of GATA-binding protein 4 regulates monocyte chemoattractant protein-1 and chemotaxis in periodontal ligament cells

BACKGROUND AND OBJECTIVES

Periodontitis is a chronic inflammatory disease of periodontal supporting tissues. The persistent inflammatory reaction depends on the release of chemokines to continuously recruit inflammation cells. GATA-binding protein 4 (GATA4) exerts effects on senescence and inflammation, while its role in periodontitis is far from clear. The present study aims to address the effect of GATA4 on regulating chemokines and the chemotaxis in periodontitis.

MATERIAL AND METHODS

Periodontitis rat models were constructed to detect the expression of GATA4 and the chemokine monocyte chemoattractant protein-1 (MCP-1) by immunohistochemistry. Lipopolysaccharide (LPS)-stimulated human periodontal ligament (PDL) cells and GATA4-knockdown by siRNA transient transfection PDL cells were used to explore the correlation between GATA4 and chemokines. Transwell assay was performed to detect the role of GATA4 for the recruitment effect of chemokines on macrophages. Mitogen-activated protein kinase (MAPK) inhibitors were scheduled to intervene in LPS-stimulated PDL cells to examine the association between MAPK signaling pathways and GATA4. The expression of GATA4, chemokines, or MAPK signaling molecules was determined by quantitative real-time polymerase chain reaction, western blotting, or cell immunofluorescence.

RESULTS

The expression of GATA4 and MCP-1 was significantly increased in periodontitis rat models and in LPS-stimulated PDL cells. Knockdown GATA4 inhibited the expression of GATA4 and MCP-1 as well as suppressed the recruitment of macrophage in LPS-stimulated PDL cells. Inhibitors of p38 and ERK1/2 signaling pathways significantly downregulated the increased expression of GATA4 and MCP-1 induced by LPS in PDL cells.

CONCLUSIONS

GATA-binding protein 4 could act as an upstream regulator of MCP-1 and as a downstream regulator of p38 and ERK1/2 signaling pathways to initiate inflammation response and regulate chemotaxis during the progression of periodontitis.

4-phenylbutyrate exerts stage-specific effects on cardiac differentiation via HDAC inhibition

4-phenylbutyrate (4-PBA), a terminal aromatic substituted fatty acid, is used widely to specifically attenuate endoplasmic reticulum (ER) stress and inhibit histone deacetylases (HDACs). In this study, we investigated the effect of 4-PBA on cardiac differentiation of mouse embryonic stem (ES) cells. Herein, we found that 4-PBA regulated cardiac differentiation in a stage-specific manner just like trichostatin A (TSA), a well-known HDAC inhibitor. 4-PBA and TSA favored the early-stage differentiation, but inhibited the late-stage cardiac differentiation via acetylation. Mechanistic studies suggested that HDACs exhibited a temporal expression profiling during cardiomyogenesis. Hdac1 expression underwent a decrease at the early stage, while was upregulated at the late stage of cardiac induction. During the early stage of cardiac differentiation, acetylation favored the induction of Isl1 and Nkx2.5, two transcription factors of cardiac progenitors. During the late stage, histone acetylation induced by 4-PBA or TSA interrupted the gene silence of Oct4, a key determinant of self-renewal and pluripotency. Thereby, 4-PBA and TSA at the late stage hindered the exit from pluripotency, and attenuated the expression of cardiac-specific contractile proteins. Overexpression of HDAC1 and p300 exerted different effects at the distinct stages of cardiac induction. Collectively, our study shows that timely manipulation of HDACs exhibits distinct effects on cardiac differentiation. And the context-dependent effects of HDAC inhibitors depend on cell differentiation states marked by the temporal expression of pluripotency-associated genes.

12-O-Tetradecanoylphorbol-13-acetate increases cardiomyogenesis through PKC/ERK signaling

12-O-Tetradecanoylphorbol-13-acetate (TPA) is the most widely used diacylglycerol (DAG) mimetic agent and inducer of protein kinase C (PKC)-mediated cellular response in biomedical studies. TPA has been proposed as a pluripotent cell differentiation factor, but results obtained have been inconsistent. In the present study we show that TPA can be applied as a cardiomyogenesis-promoting factor for the differentiation of mouse embryonic stem (mES) cells in vitro. The mechanism of TPA action is mediated by the induction of extracellular signal-regulated kinase (ERK) activity and the subsequent phosphorylation of GATA4 transcription factor. Interestingly, general mitogens (FGF, EGF, VEGF and serum) or canonical WNT signalling did not mimic the effect of TPA. Moreover, on the basis of our results, we postulate that a TPA-sensitive population of cardiac progenitor cells exists at a certain time point (after days 6–8 of the differentiation protocol) and that the proposed treatment can be used to increase the multiplication of ES cell-derived cardiomyocytes.

Advances in G protein-coupled receptor high-throughput screening

G protein-coupled receptors (GPCRs) detect compounds on the cell surface and are the starting point of a number of medically relevant signaling cascades. Indeed, over 30% of FDA approved drugs target GPCRs, making them a primary target for drug discovery. Computational and experimental high-throughput screening (HTS) approaches of clinically relevant GPCRs are a first-line drug discovery effort in biomedical research. In this opinion, we review recent advances in GPCR HTS. We focus primarily on cell-based assays, and highlight recent advances in in vitro assays using purified receptors, and computational approaches for GPCR HTS. To date, GPCR HTS has led to the identification of new and repurposing of existing drugs, and the deorphanization of GPCRs with unknown ligands. As automation equipment becomes more common, GPCR HTS will move beyond a drug discovery tool to a key technology to probe basic biological processes that will have an outsized impact on personalized medicine.