Embryonic Stem Cell Differentiation Is Regulated by SET through Interactions with p53 and β-Catenin

Antifibrotic effect of AD-1 on lipopolysaccharide-mediated fibroblast injury in L929 cells and bleomycin-induced pulmonary fibrosis in mice

20(R)-25-methoxyl-dammarane-3β,12β,20-triol (25-OCH₃-PPD, AD-1) is a dammarane ginsenoside that is isolated from Panax notoginseng. The present study aimed to explore its anti-pulmonary fibrosis (PF) effect in vitro and in vivo. L929 cells were treated with 10 μg mL^-1 lipopolysaccharide (LPS) to establish a PF model in vitro and mice were administered with 3.5 mg kg^-1 bleomycin (BLM) by endotracheal intubation to establish a PF model in vivo for investigating the anti-PF effect and its potential mechanism. The results demonstrated that AD-1 reduced the injury, extracellular matrix (ECM) buildup and α-smooth muscle actin (α-SMA) protein expression levels of L929 induced by LPS. Oral administration of AD-1 downregulated the expression of interleukins (such as IL-1β, IL-6 and IL-18), increased the expression of superoxide dismutase (SOD) and glutathione (GSH), reduced the lung coefficient and the content of hydroxyproline (HYP), and mediated the Bax/Bcl-2 protein ratio and P-p53, β-catenin and SIRT3 expression in the lung tissue of mice. Furthermore, AD-1 inhibited the expression levels of TGF-β1, TIMP-1 and α-SMA and reduced inflammatory cell infiltration and collagen deposition in the lung tissue of PF mice. These results indicated that AD-1 could alleviate PF both in vitro and in vivo, and the underlying mechanism may be related to the decrease in ECM deposition and inflammation, the enhancement of antioxidant capacity, and the mediation of lung cell apoptosis and the TGF-β1/TIMP-1/α-SMA signaling pathway, which provide a theoretical basis for the rehabilitation treatment of PF.

Generation of specialized blood vessels via lymphatic transdifferentiation

The lineage and developmental trajectory of a cell are key determinants of cellular identity. In the vascular system, endothelial cells (ECs) of blood and lymphatic vessels differentiate and specialize to cater to the unique physiological demands of each organ^1,2. Although lymphatic vessels were shown to derive from multiple cellular origins, lymphatic ECs (LECs) are not known to generate other cell types^3,4. Here we use recurrent imaging and lineage-tracing of ECs in zebrafish anal fins, from early development to adulthood, to uncover a mechanism of specialized blood vessel formation through the transdifferentiation of LECs. Moreover, we demonstrate that deriving anal-fin vessels from lymphatic versus blood ECs results in functional differences in the adult organism, uncovering a link between cell ontogeny and functionality. We further use single-cell RNA-sequencing analysis to characterize the different cellular populations and transition states involved in the transdifferentiation process. Finally, we show that, similar to normal development, the vasculature is rederived from lymphatics during anal-fin regeneration, demonstrating that LECs in adult fish retain both potency and plasticity for generating blood ECs. Overall, our research highlights an innate mechanism of blood vessel formation through LEC transdifferentiation, and provides in vivo evidence for a link between cell ontogeny and functionality in ECs.

Multivariate meta-analysis reveals global transcriptomic signatures underlying distinct human naive-like pluripotent states

The ground or naive pluripotent state of human pluripotent stem cells (hPSCs), which was initially established in mouse embryonic stem cells (mESCs), is an emerging and tentative concept. To verify this vital concept in hPSCs, we performed a multivariate meta-analysis of major hPSC datasets via the combined analytic powers of percentile normalization, principal component analysis (PCA), t-distributed stochastic neighbor embedding (t-SNE), and SC3 consensus clustering. This robust bioinformatics approach has significantly improved the predictive values of our meta-analysis. Accordingly, we revealed various similarities or dissimilarities between some naive-like hPSCs (NLPs) generated from different laboratories. Our analysis confirms some previous studies and provides new evidence concerning the existence of three distinct naive-like pluripotent states. Moreover, our study offers global transcriptomic markers that define diverse pluripotent states under various hPSC growth protocols.

Chromatin and Nuclear Architecture in Stem Cells

Here we outline the contents of Stem Cell Reports' first special issue, on chromatin and nuclear architecture in stem cells. It features both reviews and original research articles, covering emerging topics in nuclear architecture including 3D genome organization in stem cells and early development, membraneless organelles, epigenetics-related therapy, and more.