Biotechnologies such as high-throughput screening (HTS) enable evaluation of large compound libraries for their biological activity and toxic properties. In the field of drug development, embryonic stem (ES) cells have been instrumental in HTS for testing the effect of new compounds. We report an innovative method in one step to differentiate ES cells in neurons and glial cells. The four different neuronal subtypes, gamma-aminobutyric acid (GABA)-ergic, dopaminergic, serotonergic, and motor neurons, are formed in culture. This protocol is adaptable to small wells and is highly reproducible, as indicated by the Z-factor value. Moreover, by using either leukemia inhibitory factor (LIF) or recombinant Cripto protein in our culture conditions, we provide evidence that this protocol is suitable for testing the effect of different molecules on neuronal differentiation of ES cells. Finally, thanks to the simplicity in carrying out the experiment, this method provides the possibility of following the morphological evolution of the in vitro differentiating neuronal cells by timelapse videomicroscopy. Our experimental system provides a powerful tool for testing the effect of different substances on survival and/or differentiation of neuronal and glial cells in an HTS-based approach. Furthermore, using genetically modified ES cells, it would be possible to screen for drugs that have a therapeutic effect on specific neuronal pathologies or to follow, by time-lapse videomicroscopy, their ability to in vitro differentiate.

We review here some recent data about Glucose-6-phosphate dehydrogenase (G6PD), the housekeeping X-linked gene encoding the first enzyme of the pentose phosphate pathway (PPP), a NADPH-producing dehydrogenase. This enzyme has been popular among clinicians, biochemists, geneticists and molecular biologists because it is the most common form of red blood cell enzymopathy. G6PD deficient erythrocytes do not generate NADPH in any other way than through the PPP and for this reason they are more susceptible than any other cells to oxidative damage. Moreover, this enzyme has also been of crucial importance in many significant discoveries; indeed, G6PD polymorphisms have been instrumental in studying X-inactivation in the human species, as well as in establishing the clonal nature of certain tumors. G6PD deficiency, generally considered as a mild and benign condition, is significantly disadvantageous in certain environmental conditions like in presence of certain drugs. Nevertheless, G6PD deficiency has been positively selected by malaria, and recent knowledge seems to show that it also confers an advantage against the development of cancer, reduces the risk of coronary diseases and has a beneficial effect in terms of longevity.

Intellectual disability (ID) and epilepsy often occur together and have a dramatic impact on the development and quality of life of the affected children. Polyalanine (polyA)-expansion-encoding mutations of aristaless-related homeobox (ARX) cause a spectrum of X-linked ID (XLID) diseases and chronic epilepsy, including infantile spasms. We show that lysine-specific demethylase 5C (KDM5C), a gene known to be mutated in XLID-affected children and involved in chromatin remodeling, is directly regulated by ARX through the binding in a conserved noncoding element. We have studied altered ARX carrying various polyA elongations in individuals with XLID and/or epilepsy. The changes in polyA repeats cause hypomorphic ARX alterations, which exhibit a decreased trans-activity and reduced, but not abolished, binding to the KDM5C regulatory region. The altered functioning of the mutants tested is likely to correlate with the severity of XLID and/or epilepsy. By quantitative RT-PCR, we observed a dramatic Kdm5c mRNA downregulation in murine Arx-knockout embryonic and neural stem cells. Such Kdm5c mRNA diminution led to a severe decrease in the KDM5C content during in vitro neuronal differentiation, which inversely correlated with an increase in H3K4me3 signal. We established that ARX polyA alterations damage the regulation of KDM5C expression, and we propose a potential ARX-dependent path acting via chromatin remodeling.

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Embryonic stem (ES) cells can differentiate in vitro into a variety of cell types. Efforts to produce endodermal cell derivatives, including lung, liver and pancreas, have been met with modest success. Understanding how the endoderm originates from ES cells is the first step to generate specific cell types for therapeutic purposes. Recently, it has been demonstrated that inhibition of Myc or mTOR induces endodermal differentiation. Both Myc and mTOR are known to be activators of the Pentose Phosphate Pathway (PPP). We found that, differentely from wild type (wt), ES cells unable to produce pentose sugars through PPP differentiate into endodermal precursors in cell culture conditions generally non-permissive to generate them. The same effect was observed when wt ES cells were differentiated in presence of chemical inhibitors of the PPP. These data highlight a new role for metabolism. Indeed, to our knowledge, it is the first time that modulation of a metabolic pathway is described to be crucial in determining ES cell fate.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common form of red blood cell enzymopathy. The disorder has reached polymorphic frequencies in different parts of the world due to the relative protection conferred against malaria. G6PD is a housekeeping X-linked gene encoding the first enzyme of the pentose phosphate pathway, an NADPH-producing dehydrogenase. Because erythrocytes do not generate NADPH in any other way than pentose phosphate pathway, they are more susceptible than any other cells to oxidative damages. G6PD deficiency is a prime example of a hemolytic anemia due to an interaction between an intracorpuscular cause and an extracorpuscular cause, because in the majority of cases an exogenous agent triggers hemolysis. Hemolysis, in fact, can be caused by exposure to oxidant agents. Although studies performed on epidemiology, genetics and molecular biology have broaden the information on G6pd deficiency, there are still no reliable and validated methods to test drug hemolytic potential in G6PD deficient patients. The review gives an overview of current knowledge on G6pd deficiency and on the methods that have been developed so far in order to identify drugs causing acute hemolytic anemia in G6pd deficiency. Moreover, we discuss the new potential preclinical strategies to assess, in vitro and in vivo, drug hemolytic risks.

This investigation encourages the perspective to develop OFET-based biosensors in order to accurately characterize stem cells during the cardiac differentiation process and eventually increase their differentiation efficiency.

Embryonic stem (ES) cells, combining self-renewal ability with wide range tissue-specific cell differentiation, represent one of the most powerful model systems in basic research, drug discovery and biomedical applications. In the field of drug development, ES cells are instrumental in high-throughput/content screening (HTS/HCS) for the evaluation of large compound libraries to test biological activity and toxic properties. Since it is a high priority to test new compounds in vitro, before starting animal and human treatments, there is an increasing demand for new in vitro models that can be used in HTS/HCS to facilitate drug development. In order to achieve this objective, several methods for ES cell self-renewal or differentiation have been evaluated to assess their compatibility with HTS/HCS. This review describes protocols used to screen molecules able to maintain self-renewal or to induce differentiation in ectodermal, mesodermal, endodermal, and their derivative cell lines.