A generalized gene regulatory network model of stem cell differentiation for predicting lineage specifiers

in Stem Cell Reports (2016)

Differentiation of neuroepithelial stem cells into functional dopaminergic neurons in 3D microfluidic cell culture

in Lab on a Chip - Miniaturisation for Chemistry and Biology (2015), 15

Neural stem cells in Parkinson’s disease: a role for neurogenesis defects in onset and progression

in Cellular and Molecular Life Sciences (2015)

TRIM32 modulates pluripotency entry and exit by directly regulating Oct4 stability

in Scientific Reports (2015)

Gene regulatory network analysis reveals differences in site-specific cell fate determination in mammalian brain

in Frontiers in Cellular Neuroscience (2014)

Origin-Dependent Neural Cell Identities in Differentiated Human iPSCs In Vitro and after Transplantation into the Mouse Brain

in Cell Reports (2014)

Derivation and expansion using only small molecules of human neural progenitors for neurodegenerative disease modeling.

in PLoS ONE (2013), 8(3), 59252

Phenotypic drug discovery requires billions of cells for high-throughput screening (HTS) campaigns. Because up to several million different small molecules will be tested in a single HTS campaign, even ... [more ▼]

Phenotypic drug discovery requires billions of cells for high-throughput screening (HTS) campaigns. Because up to several million different small molecules will be tested in a single HTS campaign, even small variability within the cell populations for screening could easily invalidate an entire campaign. Neurodegenerative assays are particularly challenging because neurons are post-mitotic and cannot be expanded for implementation in HTS. Therefore, HTS for neuroprotective compounds requires a cell type that is robustly expandable and able to differentiate into all of the neuronal subtypes involved in disease pathogenesis. Here, we report the derivation and propagation using only small molecules of human neural progenitor cells (small molecule neural precursor cells; smNPCs). smNPCs are robust, exhibit immortal expansion, and do not require cumbersome manual culture and selection steps. We demonstrate that smNPCs have the potential to clonally and efficiently differentiate into neural tube lineages, including motor neurons (MNs) and midbrain dopaminergic neurons (mDANs) as well as neural crest lineages, including peripheral neurons and mesenchymal cells. These properties are so far only matched by pluripotent stem cells. Finally, to demonstrate the usefulness of smNPCs we show that mDANs differentiated from smNPCs with LRRK2 G2019S are more susceptible to apoptosis in the presence of oxidative stress compared to wild-type. Therefore, smNPCs are a powerful biological tool with properties that are optimal for large-scale disease modeling, phenotypic screening, and studies of early human development. [less ▲]

The Parkinson's Disease-Associated LRRK2 Mutation R1441G Inhibits Neuronal Differentiation of Neural Stem Cells.

in Stem Cells and Development (2013)

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene cause familial as well as sporadic Parkinson's disease (PD) that is characterized by an age-dependent degeneration of dopaminergic neurons. LRRK2 ... [more ▼]

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene cause familial as well as sporadic Parkinson's disease (PD) that is characterized by an age-dependent degeneration of dopaminergic neurons. LRRK2 is strongly expressed in neural stem cells (NSCs), but still the exact molecular function of LRRK2 in these cells remains unknown. By performing a systemic analysis of the gene expression profile of LRRK2-deficient NSCs, we found that the expression of several PD-associated genes, such as oxidation and reduction in mitochondria, are deregulated on LRRK2 absence. Our data, indeed, indicate that LRRK2 regulates the level of cellular oxidative stress and thereby influences the survival of NSCs. Furthermore, the lack of LRRK2 leads to an up-regulation of neuronal differentiation-inducing processes, including the Let-7a pathway. On the other hand, the constitutive mutant of LRRK2(R1441G), known to cause PD, leads to down-regulation of the same pathway. In agreement with the function of Let-7a during neuronal differentiation, LRRK2-deficient NSCs differentiate faster than wild-type cells, while LRRK2(R1441G)-expressing NSCs show impaired neuronal differentiation. These results might help better characterize the molecular mechanisms underlying the role of LRRK2 in NSCs and would further improve potential cell-replacement strategies as well as drug discovery approaches. [less ▲]

TRIM32-dependent transcription in adult neural progenitor cells regulates neuronal differentiation

in Cell Death and Disease (2013)

Direct reprogramming of fibroblasts into neural stem cells by defined factors.

in Cell Stem Cell (2012), 10(4), 465-72

Recent studies have shown that defined sets of transcription factors can directly reprogram differentiated somatic cells to a different differentiated cell type without passing through a pluripotent state ... [more ▼]

Recent studies have shown that defined sets of transcription factors can directly reprogram differentiated somatic cells to a different differentiated cell type without passing through a pluripotent state, but the restricted proliferative and lineage potential of the resulting cells limits the scope of their potential applications. Here we show that a combination of transcription factors (Brn4/Pou3f4, Sox2, Klf4, c-Myc, plus E47/Tcf3) induces mouse fibroblasts to directly acquire a neural stem cell identity-which we term as induced neural stem cells (iNSCs). Direct reprogramming of fibroblasts into iNSCs is a gradual process in which the donor transcriptional program is silenced over time. iNSCs exhibit cell morphology, gene expression, epigenetic features, differentiation potential, and self-renewing capacity, as well as in vitro and in vivo functionality similar to those of wild-type NSCs. We conclude that differentiated cells can be reprogrammed directly into specific somatic stem cell types by defined sets of specific transcription factors. [less ▲]