The proliferative and chronotropic effects of Brillantaisia nitens Lindau (Acanthaceae) extracts on pluripotent stem cells and their cardiomyocytes derivatives

Assessment of the In Vitro Cytotoxicity Effects of the Leaf Methanol Extract of Crinum zeylanicum on Mouse Induced Pluripotent Stem Cells and Their Cardiomyocytes Derivatives

Crinum zeylanicum (C. zeylanicum) is commonly used in African folk medicine to treat cardiovascular ailments. In the present study, we investigated the cytotoxic effect of the leaf methanol extract of C. zeylanicum (CZE) using mouse pluripotent stem cells (mPSCs). mPSCs and their cardiomyocytes (CMs) derivatives were exposed to CZE at different concentrations. Cell proliferation, differentiation capacity, and beating activity were assessed using xCELLigence system and microscopy for embryoid body (EB) morphology. Expression of markers associated with major cardiac cell types was examined by immunofluorescence and quantitative RT-PCR. Intracellular reactive oxygen species (ROS) levels were assessed by dichlorodihydrofluorescein diacetate staining. The results showed that the plant extract significantly reduced cell proliferation and viability in a concentration- and time-dependent manner. This was accompanied by a decrease in EB size and an increase in intracellular ROS. High concentrations of CZE decreased the expression of some important cardiac biomarkers. In addition, CZE treatment was associated with poor sarcomere structural organization of CMs and significantly decreased the amplitude and beating rate of CMs, without affecting CMs viability. These results indicate that CZE might be toxic at high concentrations in the embryonic stages of stem cells and could modulate the contracting activity of CMs.

Stem cells in natural product and medicinal plant drug discovery-An overview of new screening approaches

Natural products remain a rich source of new drugs, and the search for bioactive molecules from nature continues to play an important role in the development of new medicines. Also, there is increasing use of herbal medicines for the treatment of a plethora of diseases, and demands for more scientific evidence for their efficacy and safety remains a huge challenge. The propensity of stem cells to differentiate into almost every cell type not only holds promise for the delivery of cell-based therapies for currently incurable diseases or a useful tool in studying cell physiology and pathophysiology. Increasingly, stem cells are becoming an important tool in preclinical drug screening and toxicity testing. In this review, we examine the scientific advances made towards the use of pluripotent stem cells as a model for the screening of plant-based medicines. The combination of well-established in vitro electrophysiological and a plethora of toxicogenomic technologies, together with the optimisation of culture methods of herbal plants and pluripotent stem cells can be explored to establish the basis for efficacy, and tissue/organ-based toxicities of many currently used medicinal plants whose efficacies and toxicities remain unknown.

Petasites japonicus Stimulates the Proliferation of Mouse Spermatogonial Stem Cells

Oriental natural plants have been used as medical herbs for the treatment of various diseases for over 2,000 years. In this study, we evaluated the effect of several natural plants on the preservation of male fertility by assessing the ability of plant extracts to stimulate spermatogonial stem cell (SSC) proliferation by using a serum-free culture method. In vitro assays showed that Petasites japonicus extracts, especially the butanol fraction, have a significant effect on germ cells proliferation including SSCs. The activity of SSCs cultured in the presence of the Petasites japonicus butanol fraction was confirmed by normal colony formation and spermatogenesis following germ cell transplantation of the treated SSCs. Our findings could lead to the discovery of novel factors that activate SSCs and could be useful for the development of technologies for the prevention of male infertility.

In vitro chronotropic effects of Erythrina senegalensis DC (Fabaceae) aqueous extract on mouse heart slice and pluripotent stem cell-derived cardiomyocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Erythrina senegalensis DC (Fabaceae) bark is commonly used in sub-Saharan traditional medicine for the treatment of many diseases including gastrointestinal disorders and cardiovascular diseases. In this study, we investigated the effect of the aqueous extract of the stem bark of Erythrina senegalensis on the contractile properties of mouse ventricular slices and human induced pluripotent stem (hiPS) cell-derived cardiomyocytes. We also investigated the cytotoxic effect of the extract on mouse embryonic stem (ES) cells differentiating into cardiomyocytes (CMs).

MATERIALS AND METHODS

We used well-established electrophysiological technologies to assess the effect of Erythrina senegalensis aqueous extract (ESAE) on the beating activity of mouse ventricular slices, mouse ES and hiPS cell-derived CMs. To study the cytotoxic effect of our extract, differentiating mouse ES cells were exposed to different concentrations of ESAE. EB morphology was assessed by microscopy at different stages of differentiation whereas cell viability was measured by flow cytometry, fluorometry and immunocytochemistry. The electrical activity of CMs and heart slices were respectively captured by the patch clamp technique and microelectrode array (MEA) method following ESAE acute exposure.

RESULTS

Our findings revealed that ESAE exhibits a biphasic chronotropic activity on mouse ventricular slices with an initial low dose (0.001 and 0.01 µg/mL) decrease in beating activity followed by a corresponding significant increase in chronotropic activity at higher doses above 10 µg/mL. The muscarinic receptor blocker, atropine abolished the negative chronotropic activity of ESAE, while propranolol successfully blocked its positive chronotropic activity. ESAE showed a significant dose-dependent positive chronotropic activity on hiPS cell-derived CMs. Also, though not significantly, ESAE decreased cell viability and increased total caspase-3/7 activity of mouse ES cells in a concentration-dependent manner.

CONCLUSION

Erythrina senegalensis aqueous extract exhibits a biphasic chronotropic effect on mouse heart and a positive chronotropic activity on hiPS cell-derived CMs, suggesting a possible mechanism through muscarinic and β-adrenergic receptor pathways. Also, ESAE is not cytotoxic on mouse ES cells at concentrations up to 100 µg/mL.

Application of xCELLigence RTCA Biosensor Technology for Revealing the Profile and Window of Drug Responsiveness in Real Time

The xCELLigence technology is a real-time cellular biosensor, which measures the net adhesion of cells to high-density gold electrode arrays printed on custom-designed E-plates. The strength of cellular adhesion is influenced by a myriad of factors that include cell type, cell viability, growth, migration, spreading and proliferation. We therefore hypothesised that xCELLigence biosensor technology would provide a valuable platform for the measurement of drug responses in a multitude of different experimental, clinical or pharmacological contexts. In this manuscript, we demonstrate how xCELLigence technology has been invaluable in the identification of (1) not only if cells respond to a particular drug, but (2) the window of drug responsiveness. The latter aspect is often left to educated guess work in classical end-point assays, whereas biosensor technology reveals the temporal profile of the response in real time, which enables both acute responses and longer term responses to be profiled within the same assay. In our experience, the xCELLigence biosensor technology is suitable for highly targeted drug assessment and also low to medium throughput drug screening, which produces high content temporal data in real time.