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Astrocytes play an important role in maintaining brain homeostasis and their dysfunction is involved in a number of neurological disorders. An accessible source of astrocytes is essential to model neurological diseases and potential cell therapy approaches. Cell reprogramming techniques offer possibilities to reprogram terminally differentiated cells into other cell types. By overexpressing the three astrocytic transcription factors NFIA, NFIB, and SOX9, we showed that it is possible to directly transdifferentiate fibroblasts into functional astrocytes. These induced astrocytes (iAstrocytes) express glial fibrillary acidic protein (GFAP) and S100 calcium binding protein B (S100B), as well as other astrocytic markers. Moreover, electrophysiological properties indicate that iAstrocytes are functionally comparable to native brain astrocytes. Here we describe an optimized protocol to generate iAstrocytes starting from skin fibroblasts and this approach can be adapted for a wide range of somatic cell types.

Sanfilippo syndrome type C (mucopolysaccharidosis IIIC) is an early-onset neurodegenerative lysosomal storage disorder, which is currently untreatable. The vast majority of studies focusing on disease mechanisms of Sanfilippo syndrome were performed on non-neural cells or mouse models, which present obvious limitations. Induced pluripotent stem cells (iPSCs) are an efficient way to model human diseases in vitro. Recently developed transcription factor-based differentiation protocols allow fast and efficient conversion of iPSCs into the cell type of interest. By applying these protocols, we have generated new neuronal and astrocytic models of Sanfilippo syndrome using our previously established disease iPSC lines. Moreover, our neuronal model exhibits disease-specific molecular phenotypes, such as increase in lysosomes and heparan sulfate. Lastly, we tested an experimental, siRNA-based treatment previously shown to be successful in patients’ fibroblasts and demonstrated its lack of efficacy in neurons. Our findings highlight the need to use relevant human cellular models to test therapeutic interventions and shows the applicability of our neuronal and astrocytic models of Sanfilippo syndrome for future studies on disease mechanisms and drug development.

This article belongs to the Special Issue Cells and Materials for Disease Modeling and Regenerative Medicine., Leigh syndrome (LS) is the most frequent infantile mitochondrial disorder (MD) and is characterized by neurodegeneration and astrogliosis in the basal ganglia or the brain stem. At present, there is no cure or treatment for this disease, partly due to scarcity of LS models. Current models generally fail to recapitulate important traits of the disease. Therefore, there is an urgent need to develop new human in vitro models. Establishment of induced pluripotent stem cells (iPSCs) followed by differentiation into neurons is a powerful tool to obtain an in vitro model for LS. Here, we describe the generation and characterization of iPSCs, neural stem cells (NSCs) and iPSC-derived neurons harboring the mtDNA mutation m.13513G>A in heteroplasmy. We have performed mitochondrial characterization, analysis of electrophysiological properties and calcium imaging of LS neurons. Here, we show a clearly compromised oxidative phosphorylation (OXPHOS) function in LS patient neurons. This is also the first report of electrophysiological studies performed on iPSC-derived neurons harboring an mtDNA mutation, which revealed that, in spite of having identical electrical properties, diseased neurons manifested mitochondrial dysfunction together with a diminished calcium buffering capacity. This could lead to an overload of cytoplasmic calcium concentration and the consequent cell death observed in patients. Importantly, our results highlight the importance of calcium homeostasis in LS pathology., This research was funded by ‘Fondo de Investigación Sanitaria, Instituto de Salud Carlos III co-funded by European Regional Development Funds’, grant number PI15/00484 and PI18/00151 to M.E.G; PI13/00556 and PI16/00789 to R.G. F.Z.-D. received grant support from the Ministerio de Educación, Cultura y Deporte (FPU13/00544). M.E.G. is supported by a ‘Miguel Servet’ contract (CP16/00046) from Instituto de Salud Carlos III and European Regional Development Funds. HA received support from the Swedish Research Council.

The thesis investigates the implications for moral philosophy of research in psychology. In addition to an introduction and concluding remarks, the thesis consists of four chapters, each exploring various more specific challenges or inputs to moral philosophy from cognitive, social, personality, developmental, and evolutionary psychology. Chapter 1 explores and clarifies the issue of whether or not morality is innate. The chapter’s general conclusion is that evolution has equipped us with a basic suite of emotions that shape our moral judgments in important ways. Chapter 2 presents and investigates the challenge presented to deontological ethics by Joshua Greene’s so-called dual process theory. The chapter partly agrees with his conclusion that the dual process view neutralizes some common criticisms against utilitarianism founded on deontological intuitions, but also points to avenues left to explore for deontologists. Chapter 3 focuses on Katarzyna de Lazari-Radek and Peter Singer’s suggestion that utilitarianism is less vulnerable to so-called evolutionary debunking than other moral theories. The chapter is by and large critical of their attempt. In the final chapter 4, attention is directed at the issue of whether or not social psychology has shown that people lack stable character traits, and hence that the virtue ethical view is premised on false or tenuous assumptions. Though this so-called situationist challenge at one time seemed like a serious threat to virtue ethics, the chapter argues for a moderate position, pointing to the fragility of much of the empirical research invoked to substantiate this challenge while also suggesting revisions to the virtue ethical view as such.

List of primers/probes used in qPCR analysis. (DOCX 91 kb)