Synergistic contribution of SMAD signaling blockade and high localized cell density in the differentiation of neuroectoderm from H9 cells

Neural induction of porcine-induced pluripotent stem cells and further differentiation using glioblastoma-cultured medium

Prior to transplantation, preclinical study of safety and efficacy of neural progenitor cells (NPCs) is needed. Therefore, it is important to generate an efficient in vitro platform for neural cell differentiation in large animal models such as pigs. In this study, porcine‐induced pluripotent stem cells (iPSCs) were seeded at high cell density to a neural induction medium containing the dual Sma‐ and Mad‐related protein (SMAD) inhibitors, a TGF‐β inhibitor and BMP4 inhibitor. The dSMADi‐derived NPCs showed NPC markers such as PLAG1, NESTIN and VIMENTIN and higher mRNA expression of Sox1 compared to the control. The mRNA expression of HOXB4 was found to significantly increase in the retinoic acid‐treated group. NPCs propagated in vitro and generated neurospheres that are capable of further differentiation in neurons and glial cells. Gliobalstoma‐cultured medium including injury‐related cytokines treated porcine iPSC‐NPCs survive well in vitro and showed more neuronal marker expression compared to standard control medium. Collectively, the present study developed an efficient method for production of neural commitment of porcine iPSCs into NPCs.

Towards Multi-Organoid Systems for Drug Screening Applications

A low percentage of novel drug candidates succeed and reach the end of the drug discovery pipeline, mainly due to poor initial screening and assessment of the effects of the drug and its metabolites over various tissues in the human body. For that, emerging technologies involving the production of organoids from human pluripotent stem cells (hPSCs) and the use of organ-on-a-chip devices are showing great promise for developing a more reliable, rapid and cost-effective drug discovery process when compared with the current use of animal models. In particular, the possibility of virtually obtaining any type of cell within the human body, in combination with the ability to create patient-specific tissues using human induced pluripotent stem cells (hiPSCs), broadens the horizons in the fields of drug discovery and personalized medicine. In this review, we address the current progress and challenges related to the process of obtaining organoids from different cell lineages emerging from hPSCs, as well as how to create devices that will allow a precise examination of the in vitro effects generated by potential drugs in different organ systems.

The BAF45D Protein Is Preferentially Expressed in Adult Neurogenic Zones and in Neurons and May Be Required for Retinoid Acid Induced PAX6 Expression

Adult neurogenesis is important for the development of regenerative therapies for human diseases of the central nervous system (CNS) through the recruitment of adult neural stem cells (NSCs). NSCs are characterized by the capacity to generate neurons, astrocytes, and oligodendrocytes. To identify key factors involved in manipulating the adult NSC neurogenic fate thus has crucial implications for the clinical application. Here, we report that BAF45D is expressed in the subgranular zone (SGZ) of the dentate gyrus, the subventricular zone (SVZ) of the lateral ventricle, and the central canal (CC) of the adult spinal cord. Coexpression of BAF45D with glial fibrillary acidic protein (GFAP), a radial glial like cell marker protein, was identified in the SGZ, the SVZ and the adult spinal cord CC. Quantitative analysis data indicate that BAF45D is preferentially expressed in the neurogenic zone of the LV and the neurons of the adult CNS. Furthermore, during the neuroectoderm differentiation of H9 cells, BAF45D is required for the expression of PAX6, a neuroectoderm determinant that is also known to regulate the self-renewal and neuronal fate specification of adult neural stem/progenitor cells. Together, our results may shed new light on the expression of BAF45D in the adult neurogenic zones and the contribution of BAF45D to early neural development.

DPF2 regulates OCT4 protein level and nuclear distribution

The amount of transcription factor OCT4 is strictly regulated. A tight regulation of OCT4 levels is crucial for mammalian embryonic development and oncogenesis. However, the mechanisms underlying regulation of OCT4 protein expression and nuclear distribution are largely unknown. Here, we report that DPF2, a plant homeodomain (PHD) finger protein, is upregulated during H9 cell differentiation induced by retinoic acid. Endogenous interaction between DPF2 and OCT4 in P19 cells was revealed by an immunoprecipitation assay. GST-pull down assay proved that OCT4 protein in H9 cells and recombinant OCT4 can precipitate with DPF2 in vitro. In vitro ubiquitination assay demonstrated DPF2 might serve as an E3 ligase. Knock down of dpf2 using siRNA increased OCT4 protein level and stability in P19 cells. DPF2 siRNAs also up-regulates OCT4 but not NANOG in H9 cells. However, RA fails to downregulates OCT4 protein level in cells infected by lenitviruses containing DPF2 siRNA. Moreover, overexpression of both DPF2 and OCT4 in 293 cells proved the DPF2-OCT4 interaction. DPF2 but not PHD2 mutant DPF2 enhanced ubiquitination and degradation of OCT4 in 293 cells co-expressed DPF2 and OCT4. Both wild type DPF2 and PHD2 mutant DPF2 redistributes nuclear OCT4 without affecting DPF2-OCT4 interaction. Further analysis indicated that DPF2 decreases monomeric and mono-ubiquitinated OCT4, assembles poly-ubiquitin chains on OCT4 mainly through Ub-K48 linkage. These findings contribute to an understanding of how OCT4 protein level and nuclear distribution is regulated by its associated protein.

Data in support of DPF2 regulates OCT4 protein level and nuclear distribution

DPF2, also named ubi-d4/requiem (REQU), interacts with a protein complex containing OCT4. This paper provides data in support of the research article entitled "DPF2 regulates OCT4 protein level and nuclear distribution". The highlights include: (1) Denature-immunoprecipitation assay revealed ubiquitination of OCT4 in pluripotent H9 cells, which was enhancedby MG132, a proteasome inhibitor. (2) Well colocalization of ectopic OCT4 and FLAG-Ub was found in HeLa cells, which was also increased by MG132. (3) MG132 treatment decreased DPF2 cytoplasmic expression in vivo. These data give insights into how proteasome inhibition contributes to studying ubiquitnation of OCT4.

A simple method for differentiation of H9 cells into neuroectoderm

Human embryonic stem cells (ESCs) can form neuroectoderm (NE), providing a platform for in vitro dissection of NE formation. However, human ESCs can differentiate into all three germ layers. It thus is crucial to develop efficient methods for differentiation of human ESCs into NE cells. Both plating cell density and localized cell density (LCD) affect NE differentiation. Here, we developed a cell cluster-based NE differentiation method, in which both plating cell density and LCD are under control. Using our new method, high plating cell densities promote expression of PAX6, a NE marker protein. Two SMAD signaling blockers, SB431542 and NOGGIN, downregulate OCT4 and upregulate PAX6, while does not affect mRNA expression of GATA2 after 5 d of differentiation. Moreover, IB analysis showed a time-dependent upregulation of PAX6 and beta-III-tubulin together with a downregulation of OCT4 during the neural differentiation. Coexpression of both TH and beta-III-tubulin in the H9-derived cells was also detected, proving the NE cells have an ability to differentiate into one of the specific neurons. Together, we established a simple method for generating NE cells from H9 cells, which might contribute to develop high efficient method for neural differentiation.