The RNA helicase DDX6 controls early mouse embryogenesis by repressing aberrant inhibition of BMP signaling through miRNA-mediated gene silencing

The evolutionarily conserved RNA helicase DDX6 is a central player of post-transcriptional regulation, but its role during embryogenesis remains elusive. We here demonstrated that DDX6 enables proper cell lineage specification from pluripotent cells by analyzing Ddx6 KO mouse embryos and in vitro epiblast-like cell (EpiLC) induction system. Our study unveiled a great impact of DDX6-mediated RNA regulation on signaling pathways. Deletion of Ddx6 caused the aberrant transcriptional upregulation of the negative regulators of BMP signaling, which accompanied with enhanced Nodal signaling. Ddx6 / pluripotent cells acquired higher pluripotency with a strong inclination toward neural lineage commitment. During gastrulation, abnormally expanded Nodal expression in the primitive streak likely promoted endoderm cell fate specification while inhibiting mesoderm development. We further clarified the mechanism how DDX6 regulates cell fate determination of pluripotent cells by genetically dissecting major DDX6 pathways: processing body (P-body) formation, translational repression, mRNA decay, and miRNA-mediated silencing. P-body-related functions were dispensable, but the miRNA pathway was essential for the DDX6 function. DDX6 may prevent aberrant transcriptional upregulation of the negative regulators of BMP signaling by repressing translation of certain transcription factors through the interaction with miRNA-induced silencing complexes (miRISCs). Overall, this delineates how DDX6 affects development of the three primary germ layers during early mouse embryogenesis and the underlying mechanism of DDX6 function.

An Educational Interventional Study on Stem Cell Awareness among Eligible Beneficiaries in Central India

BACKGROUND Stem cells are pluripotent cells that continuously divide, have the ability of selfrenewal, and can generate complex tissues and organs. Globally there are almost 20 lakh stem cell centres, whereas in India we don’t have such a good network of stem cell registries. The Indian Council of Medical Research (ICMR) study says that if you have 10 lakh stem registries with you, you will be able to serve at least 40 % of the demand, but when we have 20 lakh of the global registry we are not able to meet the demand because of genetic variation. We wanted to spread awareness on stem cells from various levels like NGO’s, government, health sectors and everybody should take the initiative. The objective of the study was to assess knowledge and awareness of stem cells among eligible beneficiaries (ANC mothers and eligible couples) METHODS A cross-sectional educational interventional study was done in the Gwalior region for 2 months. A total of 100 eligible beneficiaries (ANC mothers and eligible couples) were registered for the study. Collection of questionnaire sheets & sorting out of data for analysis was done. RESULTS After awareness, 86 % of the subjects thought that the regenerated tissues from stem cells were good enough to replace the previous tissues and 91 % of the subjects were willing to donate stem cells after awareness. CONCLUSIONS Doctors and health workers can be a potential source of information for these subjects because of effective convincing strategies. KEY WORDS Stem Cells, Awareness, Umbilical Cord Blood (UCB).

HERVH-derived lncRNAs negatively regulate chromatin targeting and remodeling mediated by CHD7

Chd7 encodes an ATP-dependent chromatin remodeler which has been shown to target specific genomic loci and alter local transcription potentially by remodeling chromatin structure. De novo mutations in CHD7 are the major cause of CHARGE syndrome which features multiple developmental defects. We examined whether nuclear RNAs might contribute to its targeting and function and identified a preferential interaction between CHD7 and lncRNAs derived from HERVH loci in pluripotent stem cells. Knockdown of HERVH family lncRNAs using LNAs or knockout of an individual copy of HERVH by CRISPR-Cas9 both resulted in increased binding of CHD7 and increased levels of H3K27ac at a subset of enhancers. Depletion of HERVH family RNAs led to the activation of multiple genes. CHD7 bound HERVH RNA with high affinity but low specificity and this interaction decreased the ability of CHD7 to bind and remodel nucleosomes. We present a model in which HERVH lncRNAs act as a decoy to modulate the dynamics of CHD7 binding to enhancers in pluripotent cells and the activation of numerous genes that might impact the differentiation process.

Microtubule-dependent subcellular organisation of pluripotent cells

ABSTRACT With the advancement of cutting-edge live imaging technologies, microtubule remodelling has evolved as an integral regulator for the establishment of distinct differentiated cells. However, despite their fundamental role in cell structure and function, microtubules have received less attention when unravelling the regulatory circuitry of pluripotency. Here, we summarise the role of microtubule organisation and microtubule-dependent events required for the formation of pluripotent cells in vivo by deciphering the process of early embryogenesis: from fertilisation to blastocyst. Furthermore, we highlight current advances in elucidating the significance of specific microtubule arrays in in vitro culture systems of pluripotent stem cells and how the microtubule cytoskeleton serves as a highway for the precise intracellular movement of organelles. This Review provides an informed understanding of the intrinsic role of subcellular architecture of pluripotent cells and accentuates their regenerative potential in combination with innovative light-inducible microtubule techniques.

A stress-reduced passaging technique improves the viability of human pluripotent cells

Xeno-free culture systems have expanded the clinical and industrial application of human pluripotent stem cells (PSCs). However, yet some problems, such as the reproducibility among the experiments, remain. Here we describe an improved method for the subculture of human PSCs. The revised method significantly enhanced the viability of human PSCs by lowering DNA damage and apoptosis, resulting in more efficient and reproducible downstream applications such as gene editing, gene delivery, and directed differentiation. Furthermore, the method did not alter PSC characteristics after long-term culture and attenuated the growth advantage of abnormal subpopulations. This robust passaging method minimizes experimental error and reduces the rate of PSCs failing quality control of human PSC research and application.