Intracerebroventricular transplantation of human iPSC-derived neural stem cells (hiPSC-NSCs) into neonatal mice.

Human neural stem cells (hNSCs) hold great promises for the development of cell-based therapies for neurodegenerative diseases, given their capability to provide immunomodulatory and trophic support and to replace, to a limited extent, damaged, or lost cells. Human NSCs are under clinical evaluation for the treatment of several neurodegenerative diseases. Still, issues related to the large-scale production of clinical-grade fetal hNSCs and their allogeneic nature-requiring immunosuppressive regimens-have hampered their full exploitation as therapeutics. NSCs derived from human induced pluripotent stem cells (hiPSCs) provide a valuable alternative to fetal hNSCs since they can be generated from autologous or HLA-matched donors expanded for large-scale clinical-grade production, and are amenable for gene addition/gene editing strategies, thus potentially addressing CNS diseases of genetic origin. The prospective use of hiPSC-derived NSCs (hiPSC-NSCs) for CNS-directed therapies demands a careful evaluation of the efficacy and safety of these cell populations in animal models. Here, we describe a protocol for the transplantation and phenotypical characterization of hiPSC-NSCs in neonatal immunodeficient mice. This protocol is relevant to assessing the safety and the efficacy of hiPSC-NSC transplantation to target early-onset neurodegenerative or demyelinating CNS diseases.

Generation of neuronal/glial mixed cultures from human induced pluripotent stem cells (hiPSCs).

For a long time, the understanding of neurological diseases has been limited by the lack of representative experimental models able to recapitulate essential features of the human pathologies. Human induced pluripotent stem cells (hiPSCs) have emerged as a powerful tool for disease modeling, drug screening, and the development of novel cell and gene therapies. A critical issue for the prospective use of hiPSCs in basic and translational research for central nervous system (CNS) disorders is to validate robust protocols able to efficiently differentiate pluripotent cells into neurons and glial cells of interest, specifically those that are most affected in pathological conditions. We describe here a three-step differentiation protocol optimized for feeder-free hiPSCs. The protocol includes a first step of neural induction mediated by dual SMAD inhibition to generate homogeneous populations of neural progenitor cells (NPCs), a second step of NPCs expansion, and a third phase of NPCs differentiation into a mixed culture of neurons, oligodendrocytes, and astrocytes. This experimental platform is relevant to recapitulate the neural induction of hiPSCs and to monitor NPC lineage specification and neuronal/glial differentiation in physiological conditions as well as in the context of CNS diseases. The protocol allows monitoring early pathological hallmarks in the different CNS cell types, also offering a simplified in vitro model to study the neuronal-glial crosstalk.

Human iPSC-based neurodevelopmental models of globoid cell leukodystrophy uncover patient- and cell type-specific disease phenotypes.

Globoid cell leukodystrophy (GLD) is a rare neurodegenerative lysosomal storage disease caused by an inherited deficiency of ß-galactocerebrosidase (GALC). GLD pathogenesis and therapeutic correction have been poorly studied in patient neural cells. Here, we investigated the impact of GALC deficiency and lentiviral vector-mediated GALC rescue/overexpression in induced pluripotent stem cell (iPSC)-derived neural progenitors and neuronal/glial progeny obtained from two GLD patients. GLD neural progeny displayed progressive psychosine storage, oligodendroglial and neuronal defects, unbalanced lipid composition, and early activation of cellular senescence, depending on the disease-causing mutation. The partial rescue of the neural differentiation program upon GALC reconstitution and psychosine clearance suggests multiple mechanisms contributing to neural pathology in GLD. Also, the pathological phenotype associated to supraphysiological GALC levels highlights the need of regulated GALC expression for proper human neural commitment/differentiation. These data have important implications for establishing safe therapeutic strategies to enhance disease correction of GLD.

Friedreich ataxia-induced pluripotent stem cell-derived neurons show a cellular phenotype that is corrected by a benzamide HDAC inhibitor.

We employed induced pluripotent stem cell (iPSC)-derived neurons obtained from Friedreich ataxia (FRDA) patients and healthy subjects, FRDA neurons and CT neurons, respectively, to unveil phenotypic alterations related to frataxin (FXN) deficiency and investigate if they can be reversed by treatments that upregulate FXN. FRDA and control iPSCs were equally capable of differentiating into a neuronal or astrocytic phenotype. FRDA neurons showed lower levels of iron­sulfur (Fe­S) and lipoic acid-containing proteins, higher labile iron pool (LIP), higher expression of mitochondrial superoxide dismutase (SOD2), increased reactive oxygen species (ROS) and lower reduced glutathione (GSH) levels, and enhanced sensitivity to oxidants compared with CT neurons, indicating deficient Fe­S cluster biogenesis, altered iron metabolism, and oxidative stress. Treatment with the benzamide HDAC inhibitor 109 significantly upregulated FXN expression and increased Fe­S and lipoic acid-containing protein levels, downregulated SOD2 levels, normalized LIP and ROS levels, and almost fully protected FRDA neurons from oxidative stress-mediated cell death. Our findings suggest that correction of FXN deficiency may not only stop disease progression, but also lead to clinical improvement by rescuing still surviving, but dysfunctional neurons.