Effects of danazol on endothelial cell function and angiogenesis

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.

Identification of drug combinations on the basis of machine learning to maximize anti-aging effects

Aging is a multifactorial process that involves numerous genetic changes, so identifying anti-aging agents is quite challenging. Age-associated genetic factors must be better understood to search appropriately for anti-aging agents. We utilized an aging-related gene expression pattern-trained machine learning system that can implement reversible changes in aging by linking combinatory drugs. In silico gene expression pattern-based drug repositioning strategies, such as connectivity map, have been developed as a method for unique drug discovery. However, these strategies have limitations such as lists that differ for input and drug-inducing genes or constraints to compare experimental cell lines to target diseases. To address this issue and improve the prediction success rate, we modified the original version of expression profiles with a stepwise-filtered method. We utilized a machine learning system called deep-neural network (DNN). Here we report that combinational drug pairs using differential expressed genes (DEG) had a more enhanced anti-aging effect compared with single independent treatments on leukemia cells. This study shows potential drug combinations to retard the effects of aging with higher efficacy using innovative machine learning techniques.

Computational drug repositioning for peripheral arterial disease: prediction of anti-inflammatory and pro-angiogenic therapeutics

Peripheral arterial disease (PAD) results from atherosclerosis that leads to blocked arteries and reduced blood flow, most commonly in the arteries of the legs. PAD clinical trials to induce angiogenesis to improve blood flow conducted in the last decade have not succeeded. We have recently constructed PADPIN, protein-protein interaction network (PIN) of PAD, and here we combine it with the drug-target relations to identify potential drug targets for PAD. Specifically, the proteins in the PADPIN were classified as belonging to the angiome, immunome, and arteriome, characterizing the processes of angiogenesis, immune response/inflammation, and arteriogenesis, respectively. Using the network-based approach we predict the candidate drugs for repositioning that have potential applications to PAD. By compiling the drug information in two drug databases DrugBank and PharmGKB, we predict FDA-approved drugs whose targets are the proteins annotated as anti-angiogenic and pro-inflammatory, respectively. Examples of pro-angiogenic drugs are carvedilol and urokinase. Examples of anti-inflammatory drugs are ACE inhibitors and maraviroc. This is the first computational drug repositioning study for PAD.

Classical nuclear hormone receptor activity as a mediator of complex concentration response relationships for endocrine active compounds

Nonmonotonic concentration response relationships are frequently observed for endocrine active ligands that act via nuclear receptors. The curve of best fit for nonmonotonic concentration response relationships are often inverted U-shaped with effects at intermediate concentrations that are different from effects at higher or lower concentrations. Cytotoxicity is a major mode of action responsible for inverted U-shaped concentration response relationships. However, evidence suggests that ligand selectivity, activation of multiple molecular targets, concerted regulation of multiple opposing endpoints, and multiple ligand binding sites within nuclear receptors also contribute to nonmonotonic concentration response relationships of endocrine active ligands. This review reports the current understanding of mechanisms involved in classical nuclear receptor mediated nonmonotonic concentration response relationships with a focus on studies published between 2012 and 2014.

Emerging drugs for diabetic macular edema

INTRODUCTION

Diabetic macular edema (DME) is the most common cause of visual impairment due to diabetic retinopathy. The treatment of DME has recently undergone a paradigm shift. Traditionally, photocoagulation was standard treatment, but pharmacologic therapies are becoming increasingly used for this purpose. All currently available drug therapies for DME are either anti-VEGF agents or corticosteroids.

AREAS COVERED

The pathogenesis of DME involves angiogenesis, inflammation and oxidative stress. The scientific rationale to treat DME through the pharmacologic blockade of VEGF and other pro-angiogenic factors is discussed. The fluocinolone insert is approved for the treatment of DME in several European countries, but not in the US at this time. Some medications that are already approved for other retinal diseases, most prominently aflibercept and the dexamethasone delivery system, have recently obtained approval for DME in the US. Other compounds are being studied in earlier-phase clinical trials.

EXPERT OPINION

Pharmacologic treatment of DME will likely become increasingly used, especially for patients with edema involving the fovea. At this time, the two main classes of medication for treatment of DME are anti-VEGF agents and corticosteroids. As we continue to collect clinical trials data, the precise role of individual agents, and the continuing role for photocoagulation, will become more clear.

Biphasic effect of danazol on human vascular endothelial cell permeability and f-actin cytoskeleton dynamics

Breakdown of endothelial barrier function is a hallmark event across a variety of pathologies such as inflammation, cancer, and diabetes. It has also been appreciated that steroid hormones impart direct biological activity on endothelial cells at many levels. The purpose of this investigation was to explore the effect of the androgen-like steroid, danazol, on endothelial cell barrier function in vitro. Primary human endothelial cells exposed to 0.01-50 μM danazol were evaluated for changes in permeability. We found that danazol altered endothelial permeability in a biphasic manner in which nanomolar concentrations enhance barrier function while micromolar concentrations are detrimental. Monitoring of trans-endothelial electrical resistance demonstrated that these barrier enhancing effects were rapid (within 5 min) and lasted for over 24h. Analysis of intracellular f-actin organization showed that barrier enhancement also correlated with the formation of a submembranous cortical actin ring. Conversely, at higher danazol concentrations, contractile cell phenotypes were observed, represented by stress fiber formation. Competitive binding studies performed using steroid hormone receptor antagonists proved that this activity is the result of androgen and estrogen receptor ligation. These findings suggest that low dose danazol may provide a therapeutic window for diseases involving vascular leakage.

Endothelial cell surface vimentin binding peptide induces angiogenesis under hypoxic/ischemic conditions

We have previously identified several angiogenic peptides that bind cell surface proteins by screening a phage display peptide library on human umbilical endothelial cells exposed to hypoxic conditions. In this study we describe one of the selected peptides, SP. We found by protein precipitation of endothelial cell lysates that the 12 amino acid SP peptide binds cell surface vimentin. Surprisingly, vimentin was detected on the cell surface of about 30% of intact endothelial cells under both normoxic and hypoxic conditions, as was demonstrated by fluorocytometric analysis on viable cells. The assessment of SP in the induction of angiogenesis was established by a significant increase in endothelial cell proliferation and tube formation under hypoxic conditions and not under normoxic conditions. Cell proliferation and tube length increased two-fold in endothelial cells in the presence of 10 ng/ml SP peptide when compared to controls. The specificity of SP binding to vimentin was demonstrated by SP inhibition of anti-vimentin binding and by the inhibition of tube formation in cells transfected with siRNA against vimentin. Local intramuscular administrations of the peptide SP to ischemic hind limbs using the mouse hind limb ischemia model, demonstrated that SP inoculated at 1 and 10 μg, improved blood perfusion compared to inoculations with an irrelevant peptide or PBS. The recovery of blood perfusion correlated with the increase in the number of detectable capillaries in the ischemic limb. The development of novel peptides for the induction of pro-angiogenic activity may pave the way for new therapeutic strategies in the treatment of cardiovascular ischemic diseases.