Peptidomimetic small-molecule compounds promoting cardiogenesis of stem cells

Recent progress in the manipulation of biochemical and biophysical cues for engineering functional tissues

Tissue engineering (TE) is currently considered a cutting-edge discipline that offers the potential for developing treatments for health conditions that negatively affect the quality of life. This interdisciplinary field typically involves the combination of cells, scaffolds, and appropriate induction factors for the regeneration and repair of damaged tissue. Cell fate decisions, such as survival, proliferation, or differentiation, critically depend on various biochemical and biophysical factors provided by the extracellular environment during developmental, physiological, and pathological processes. Therefore, understanding the mechanisms of action of these factors is critical to accurately mimic the complex architecture of the extracellular environment of living tissues and improve the efficiency of TE approaches. In this review, we recapitulate the effects that biochemical and biophysical induction factors have on various aspects of cell fate. While the role of biochemical factors, such as growth factors, small molecules, extracellular matrix (ECM) components, and cytokines, has been extensively studied in the context of TE applications, it is only recently that we have begun to understand the effects of biophysical signals such as surface topography, mechanical, and electrical signals. These biophysical cues could provide a more robust set of stimuli to manipulate cell signaling pathways during the formation of the engineered tissue. Furthermore, the simultaneous application of different types of signals appears to elicit synergistic responses that are likely to improve functional outcomes, which could help translate results into successful clinical therapies in the future.

Generation of muscle progenitors from human-induced pluripotent stem cells

Background

Small molecules have a role in the differentiation of human-induced pluripotent stem cells (hiPSCs) into different cell linages. The aim of this study was to evaluate the differentiation of hiPSCs into cardiac or skeletal myogenic progenitors with a single small molecule.

Methods

hiPSCs were treated with three different small molecules such as Isoxazole-9, Danazol and Givinostat in serum-free medium for 7 days. Cell viability, qRT-PCR, western blots, and immunostaining were assessed after treatment of hiPSCs with small molecules.

Results

Higher hiPSC viability was observed in hiPSCs treated with Isoxazole-9 (25 µM), Danazol (25 µM) and Givinostat (150 nM) versus control (P < 0.05). Givinostat had dual effect by generating both skeletal and cardiac progenitor cells versus Isoxazole-9 and Danazol after 7 days. Givinostat treatment induced upregulation of skeletal myogenic genes and their protein expression levels on day 4 and further increased on day 8 (P < 0.05) versus control. Furthermore,positive stained cells for Pax3, Myf5, MyoD1, dystrophin, desmin, myogenin, and β-catenin at 1 month. Givinostat increased upregulation of cardiac gene expression levels versus control after day 4 (P < 0.05), with positive stained cells for Nkx2.5, GATA4, TnT, TnI, connexin 43 and α-sarcomeric actinin at 1 month.

Conclusions

Pretreatment of hiPSCs with Givinostat represents a viable strategy for producing both cardiac/skeletal myogenic progenitors in vitro for cell therapies against myocardial infarction and Duchenne muscular dystrophy.

Herbal Extract from Codonopsis pilosula (Franch.) Nannf. Enhances Cardiogenic Differentiation and Improves the Function of Infarcted Rat Hearts

Background: The roots of Codonopsis pilosula (Franch.) Nannf. have been used in traditional Chinese medicine for treating cardiovascular disease. In the current study, we aimed to discover herbal extracts from C. pilosula that are capable of improving cardiac function of infarcted hearts to develop a potential therapeutic approach. Methods: A mouse embryonic stem (ES) cell-based model with an enhanced green fluorescent protein (eGFP) reporter driven by a cardiomyocyte-specific promoter, the α-myosin heavy chain, was constructed to evaluate the cardiogenic activity of herbal extracts. Then, herbal extracts from C. pilosula with cardiogenic activity based on an increase in eGFP expression during ES cell differentiation were further tested in a rat myocardial infarction model with left anterior descending artery (LAD) ligation. Cardiac function assessments were performed using echocardiography, 1, 3, and 6 weeks post LAD ligation. Results: The herbal extract 417W from C. pilosula was capable of enhancing cardiogenic differentiation in mouse ES cells in vitro. Echocardiography results in the LAD-ligated rat model revealed significant improvements in the infarcted hearts at least 6 weeks after 417W treatment that were determined based on left ventricle fractional shortening (FS), fractional area contraction (FAC), and ejection fraction (EF). Conclusions: The herbal extract 417W can enhance the cardiogenic differentiation of ES cells and improve the cardiac function of infarcted hearts.

Stemistry: the control of stem cells in situ using chemistry

A new paradigm for drug research has emerged, namely the deliberate search for molecules able to selectively affect the proliferation, differentiation, and migration of adult stem cells within the tissues in which they exist. Recently, there has been significant interest in medicinal chemistry toward the discovery and design of low molecular weight molecules that affect stem cells and thus have novel therapeutic activity. We believe that a successful agent from such a discover program would have profound effects on the treatment of many long-term degenerative disorders. Among these conditions are examples such as cardiovascular decay, neurological disorders including Alzheimer's disease, and macular degeneration, all of which have significant unmet medical needs. This perspective will review evidence from the literature that indicates that discovery of such agents is achievable and represents a worthwhile pursuit for the skills of the medicinal chemist.

Heart regeneration: opportunities and challenges for drug discovery with novel chemical and therapeutic methods or agents

Following a heart attack, more than a billion cardiac muscle cells (cardiomyocytes) can be killed, leading to heart failure and sudden death. Much research in this area is now focused on the regeneration of heart tissue through differentiation of stem cells, proliferation of existing cardiomyocytes and cardiac progenitor cells, and reprogramming of fibroblasts into cardiomyocytes. Different chemical modalities (i.e. methods or agents), ranging from small molecules and RNA approaches (including both microRNA and anti-microRNA) to modified peptides and proteins, are showing potential to meet this medical need. In this Review, we outline the recent advances in these areas and describe both the modality and progress, including novel screening strategies to identify hits, and the upcoming challenges and opportunities to develop these hits into pharmaceuticals, at which chemistry plays a key role.

Small molecule screening in human induced pluripotent stem cell-derived terminal cell types

A need for better clinical outcomes has heightened interest in the use of physiologically relevant human cells in the drug discovery process. Patient-specific human induced pluripotent stem cells may offer a relevant, robust, scalable, and cost-effective model of human disease physiology. Small molecule high throughput screening in human induced pluripotent stem cell-derived cells with the intent of identifying novel therapeutic compounds is starting to influence the drug discovery process; however, the use of these cells presents many high throughput screening development challenges. This technology has the potential to transform the way drug discovery is performed.

Identification and characterization of CW108F, a novel β-carboline compound that promotes cardiomyogenesis of stem cells

AIMS

The aim of this study was to identify new compounds that induce cardiomyocyte differentiation of stem cells through cell-based screening and investigate lineage specificity and mechanisms in vitro.

MAIN METHODS

Embryoid bodies (EBs) formed from TC-1/KH2 mouse embryonic stem cells (ESCs) carrying the gene for enhanced green fluorescent protein (EGFP) under the control of the α-myosin heavy chain (MHC) promoter were treated with test compounds. The number of cardiomyocyte-like (EGFP-expressing) cells in EBs was determined by fluorescence-activated cell sorting. Cardiomyocyte differentiation was further confirmed using lineage-specific biochemical assays and by investigating the expression of cardiomyocyte-specific and "stemness"-associated genes. Nuclear factor-kappaB (NF-κB) signaling activity was measured in A549 cells using a reporter-gene assay.

KEY FINDINGS

A β-carboline compound, designated CW108F, increased the number of mouse ESCs expressing α-MHC promoter-driven EGFP and the proportion of beating EBs. CW108F also increased expression of MHC in P19 stem cells, but did not induce osteogenesis of MC3T3-E1 cells, suggesting lineage-specific activity toward cardiomyocytes. CW108F upregulated expression of cardiac-specific GATA-4 and atrial natriuretic factor (ANF) genes in TC-1/KH2 cells, but downregulated expression of the stemness genes, Oct-4 and brachyury. CW108F inhibited NF-κB transcriptional activity, an effect that might contribute to its cardiomyogenesis-promoting activity.

SIGNIFICANCE

The results of this study suggest that the novel β-carboline, CW108F, promotes the differentiation of ESCs into cardiomyocytes and may be useful for investigating molecular pathways of cardiomyogenesis and generating cardiomyocytes from ESCs.