LIF-dependent primitive neural stem cells derived from mouse ES cells represent a reversible stage of neural commitment

Exome sequencing of families from Ghana reveals known and candidate hearing impairment genes

We investigated hearing impairment (HI) in 51 families from Ghana with at least two affected members that were negative for GJB2 pathogenic variants. DNA samples from 184 family members underwent whole-exome sequencing (WES). Variants were found in 14 known non-syndromic HI (NSHI) genes [26/51 (51.0%) families], five genes that can underlie either syndromic HI or NSHI [13/51 (25.5%)], and one syndromic HI gene [1/51 (2.0%)]. Variants in CDH23 and MYO15A contributed the most to HI [31.4% (16/51 families)]. For DSPP, an autosomal recessive mode of inheritance was detected. Post-lingual expression was observed for a family segregating a MARVELD2 variant. To our knowledge, seven novel candidate HI genes were identified (13.7%), with six associated with NSHI (INPP4B, CCDC141, MYO19, DNAH11, POTEI, and SOX9); and one (PAX8) with Waardenburg syndrome. MYO19 and DNAH11 were replicated in unrelated Ghanaian probands. Six of the novel genes were expressed in mouse inner ear. It is known that Pax8-/- mice do not respond to sound, and depletion of Sox9 resulted in defective vestibular structures and abnormal utricle development. Most variants (48/60; 80.0%) have not previously been associated with HI. Identifying seven candidate genes in this study emphasizes the potential of novel HI genes discovery in Africa.

Combinational therapy of lithium and human neural stem cells in rat spinal cord contusion model

A large number of treatment approaches have been used for spinal cord injury improvement, a medically incurable disorder, and subsequently stem cell transplantation appears to be a promising strategy. The main objective of this study is to ascertain whether combinational therapy of human neural stem cells (hNSCs) together with lithium chloride improves cell survival, proliferation, and differentiation in a rat spinal contusion model, or not. Contusive spinal cord injury was implemented on Wistar male rats. Experimental groups comprised of: control, hNSCs transplanted, lithium chloride (Li), and hNSCs and lithium chloride (hNSCs + Li). In every experimental group, locomotor activity score and motor evoked potential (MEP) were performed to evaluate motor recovery as well as histological assessments to determine mechanisms of improvement. In accordance with our results, the hNSCs + Li and the Li groups showed significant improvement in locomotor scores and MEP. Also, Histological assessments revealed that transplanted hNSCs are capable of differentiation and migration along the spinal cord. Although NESTIN-positive cells were proliferated significantly in the Lithium group in comparison with control and the hNSCs + Li groups, the quantity of ED1 cells in the hNSCs + Li was significantly larger than the other two groups. Our results demonstrate that combinational therapy of hNSCs with lithium chloride and lithium chloride individually are adequate for ameliorating more than partial functional recovery and endogenous repair in spinal cord-injured rats.

Neural stem cell heterogeneity in the mammalian forebrain

The brain was long considered an organ that underwent very little change after development. It is now well established that the mammalian central nervous system contains neural stem cells that generate progeny that are capable of making new neurons, astrocytes, and oligodendrocytes throughout life. The field has advanced rapidly as it strives to understand the basic biology of these precursor cells, and explore their potential to promote brain repair. The purpose of this review is to present current knowledge about the diversity of neural stem cells in vitro and in vivo, and highlight distinctions between neural stem cell populations, throughout development, and within the niche. A comprehensive understanding of neural stem cell heterogeneity will provide insights into the cellular and molecular regulation of neural development and lifelong neurogenesis, and will guide the development of novel strategies to promote regeneration and neural repair.

Single Cell Analysis Reveals Concomitant Transcription of Pluripotent and Lineage Markers During the Early Steps of Differentiation of Embryonic Stem Cells

The differentiation of embryonic stem cells is associated with extensive changes in gene expression. It is not yet clear whether these changes are the result of binary switch-like mechanisms or that of continuous and progressive variation. Here, I have used immunostaining and single molecule RNA fluorescence in situ hybridization (FISH) to assess changes in the expression of the well-known pluripotency-associated gene Pou5f1 (also known as Oct4) and early differentiation markers Sox1 and T-brachyury in single cells during the early steps of differentiation of mouse embryonic stem cells. I found extensive overlap between the expression of Pou5f1/Sox1 or Pou5f1/T-brachyury shortly after the initiation of differentiation towards either the neuronal or the mesendodermal lineage, but no evidence of correlation between their respective expression levels. Quantitative analysis of transcriptional output at the sites of nascent transcription revealed that Pou5f1 and Sox1 were transcribed in pulses and that embryonic stem cell differentiation was accompanied by changes in pulsing frequencies. The progressive induction of Sox1 was further associated with an increase in the average size of individual transcriptional bursts. Surprisingly, single cells that actively and simultaneously transcribe both the pluripotency- and the lineage-associated genes could easily be found in the differentiating population. The results presented here show for the first time that lineage priming can occur in cells that are actively transcribing a pluripotent marker. Furthermore, they suggest that this process is associated with changes in transcriptional dynamics.

Generation of functional neurons from feeder-free, keratinocyte-derived equine induced pluripotent stem cells

Pluripotent stem cells (PSCs) offer unprecedented biomedical potential not only in relation to humans but also companion animals, particularly the horse. Despite this, attempts to generate bona fide equine embryonic stem cells have been unsuccessful. A very limited number of induced PSC lines have so far been generated from equine fibroblasts but their potential for directed differentiation into clinically relevant tissues has not been explored. In this study, we used retroviral vectors to generate induced pluripotent stem cells (iPSCs) with comparatively high efficiency from equine keratinocytes. Expression of endogenous PSC markers (OCT4, SOX2, LIN28, NANOG, DNMT3B, and REX1) was effectively restored in these cells, which could also form in vivo several tissue derivatives of the three germ layers, including functional neurons, keratinized epithelium, cartilage, bone, muscle, and respiratory and gastric epithelia. Comparative analysis of different reprogrammed cell lines revealed an association between the ability of iPSCs to form well-differentiated teratomas and the distinct endogenous expression of OCT4 and REX1 and reduced expression of viral transgenes. Importantly, unlike in previous studies, equine iPSCs were successfully expanded using simplified feeder-free culture conditions, constituting significant progress toward future biomedical applications. Further, under appropriate conditions equine iPSCs generated cells with features of cholinergic motor neurons including the ability to generate action potentials, providing the first report of functional cells derived from equine iPSCs. The ability to derive electrically active neurons in vitro from a large animal reveals highly conserved pathways of differentiation across species and opens the way for new and exciting applications in veterinary regenerative medicine.