Zinc finger E-box-binding homeobox 1 (ZEB1) is required for neural differentiation of human embryonic stem cells.

Human pluripotent stem cells hold great promise for improving regenerative medicine. However, a risk for tumor formation and difficulties in generating large amounts of subtype derivatives remain the major obstacles for clinical applications of stem cells. Here, we discovered that zinc finger E-box-binding homeobox 1 (ZEB1) is highly expressed upon differentiation of human embryonic stem cells (hESCs) into neuronal precursors. CRISPR/Cas9-mediated ZEB1 depletion did not impede neural fate commitment, but prevented hESC-derived neural precursors from differentiating into neurons, indicating that ZEB1 is required for neuronal differentiation. ZEB1 overexpression not only expedited neural differentiation and neuronal maturation, which ensured safer neural cell transplantation, but also facilitated the generation of excitatory cortical neurons, which were valuable for managing certain neurological disorders, such as Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). Our study provides useful information on how human neural cells are generated, which may help in forming strategies for developing and improving replacement therapies for treating patients with neurological diseases.

A Human-Specific De Novo Gene Promotes Cortical Expansion and Folding.

Newly originated de novo genes have been linked to the formation and function of the human brain. However, how a specific gene originates from ancestral noncoding DNAs and becomes involved in the preexisting network for functional outcomes remains elusive. Here, a human-specific de novo gene, SP0535, is identified that is preferentially expressed in the ventricular zone of the human fetal brain and plays an important role in cortical development and function. In human embryonic stem cell-derived cortical organoids, knockout of SP0535 compromises their growth and neurogenesis. In SP0535 transgenic (TG) mice, expression of SP0535 induces fetal cortex expansion and sulci and gyri-like structure formation. The progenitors and neurons in the SP0535 TG mouse cortex tend to proliferate and differentiate in ways that are unique to humans. SP0535 TG adult mice also exhibit improved cognitive ability and working memory. Mechanistically, SP0535 interacts with the membrane protein Na+ /K+ ATPase subunit alpha-1 (ATP1A1) and releases Src from the ATP1A1-Src complex, allowing increased level of Src phosphorylation that promotes cell proliferation. Thus, SP0535 is the first proven human-specific de novo gene that promotes cortical expansion and folding, and can function through incorporating into an existing conserved molecular network.

Continual Deletion of Spinal Microglia Reforms Astrocyte Scar Favoring Axonal Regeneration.

Astrocyte scar formation after spinal cord injury (SCI) efficiently limits the accurate damage but physically restricts the following axon regeneration. Lately, fine tuning scar formation is becoming a novel strategy to develop SCI treatment, yet how to leverage these opposite effects remains challenging. Here, utilizing an improved drug administration approach, we show that in a mouse model of spinal cord injury, continual deletion of microglia, especially upon scar formation, by pexidartinib decreases the amount of microglia-derived collagen I and reforms the astrocyte scar. The astrocytes become less compacted in the scar, which permits axon regeneration and extension. Although continual microglia deletion did not significantly improve the locomotive performance of the SCI mice, it did ameliorate their weight loss, possibly by improving their relevant health conditions. We thus identified a novel approach to regulate astrocyte scars for improved axon regeneration, which is indicative of the clinical treatment of SCI patients.

A Chemical Recipe for Generation of Clinical-Grade Striatal Neurons from hESCs.

Differentiation of human pluripotent stem cells (hPSCs) into striatal medium spiny neurons (MSNs) promises a cell-based therapy for Huntington's disease. However, clinical-grade MSNs remain unavailable. Here, we developed a chemical recipe named XLSBA to generate clinical-grade MSNs from embryonic stem cells (ESCs). We introduced the γ-secretase inhibitor DAPT into the recipe to accelerate neural differentiation, and replaced protein components with small molecules. Using this optimized protocol we could efficiently direct regular human ESCs (hESCs) as well as clinical-grade hESCs to lateral ganglionic eminence (LGE)-like progenitors and striatal MSNs within less than half of the time than previous protocols (within 14 days and 21 days, respectively). These striatal cells expressed appropriate MSN markers and electrophysiologically acted like authentic MSNs. Upon transplantation into brains of neonatal mice or mouse model of Huntington's disease, they exhibited sufficient safety and reasonable efficacy. Therefore, this quick and highly efficient derivation of MSNs offers unprecedented access to clinical application.