CRISPR-Cas9 screens reveal regulators of ageing in neural stem cells.

Ageing impairs the ability of neural stem cells (NSCs) to transition from quiescence to proliferation in the adult mammalian brain. Functional decline of NSCs results in the decreased production of new neurons and defective regeneration following injury during ageing1-4. Several genetic interventions have been found to ameliorate old brain function5-8, but systematic functional testing of genes in old NSCs-and more generally in old cells-has not been done. Here we develop in vitro and in vivo high-throughput CRISPR-Cas9 screening platforms to systematically uncover gene knockouts that boost NSC activation in old mice. Our genome-wide screens in primary cultures of young and old NSCs uncovered more than 300 gene knockouts that specifically restore the activation of old NSCs. The top gene knockouts are involved in cilium organization and glucose import. We also establish a scalable CRISPR-Cas9 screening platform in vivo, which identified 24 gene knockouts that boost NSC activation and the production of new neurons in old brains. Notably, the knockout of Slc2a4, which encodes the GLUT4 glucose transporter, is a top intervention that improves the function of old NSCs. Glucose uptake increases in NSCs during ageing, and transient glucose starvation restores the ability of old NSCs to activate. Thus, an increase in glucose uptake may contribute to the decline in NSC activation with age. Our work provides scalable platforms to systematically identify genetic interventions that boost the function of old NSCs, including in vivo, with important implications for countering regenerative decline during ageing.

Autophagic state prospectively identifies facultative stem cells in the intestinal epithelium.

The intestinal epithelium exhibits a rapid and efficient regenerative response to injury. Emerging evidence supports a model where plasticity of differentiated cells, particularly those in the secretory lineages, contributes to epithelial regeneration upon ablation of injury-sensitive stem cells. However, such facultative stem cell activity is rare within secretory populations. Here, we ask whether specific functional properties predict facultative stem cell activity. We utilize in vivo labeling combined with ex vivo organoid formation assays to evaluate how cell age and autophagic state contribute to facultative stem cell activity within secretory lineages. Strikingly, we find that cell age (time elapsed since cell cycle exit) does not correlate with secretory cell plasticity. Instead, high autophagic vesicle content predicts plasticity and resistance to DNA damaging injury independently of cell lineage. Our findings indicate that autophagic status prior to injury serves as a lineage-agnostic marker for the prospective identification of facultative stem cells.

Recent trends in stem cell therapy for premature ovarian insufficiency and its therapeutic potential: a review.

Stem cell therapy is attracting attention in the field of regenerative medicine and is advancing rapidly. Many recent studies have applied stem cell therapy to treat reproductive system diseases; however, data are not yet available as to whether this therapy shows enhanced therapeutic effects. This paper analyzes recent preclinical studies on stem cell therapy for ovarian dysfunction in several types of animal models. Several clinical trials and pending projects are also discussed. This review will provide a background for developing stem cell therapies to enhance ovarian function.

Human placenta-derived mesenchymal stem cells trigger repair system in TAA-injured rat model via antioxidant effect.

Oxidative stress induces damages of various cell types or tissues through a repetitive imbalance between the systemic manifestation of reactive oxygen species (ROS) and detoxification of the reactive intermediates. Thioacetamide (TAA) is well known for causing several degenerative diseases by oxidative stress. However, study of the antioxidant mechanisms of stem cells in TAA-injured rat model is insufficient. Therefore, we investigated the effect of placenta-derived mesenchymal stem cells (PD-MSCs) transplantation on liver and ovary of TAA-injured rat models to study the antioxidant effect in degenerative diseases. In TAA-injured rat model, PD-MSCs engrafted into damaged organ including liver and ovary in PD-MSCs transplanted groups (Tx) compared with non-transplanted groups (NTx) (*p<0.05). Transplanted PD-MSCs reduced inflammatory factors and upregulated oxidative stress factors in Tx compared with NTx (*p<0.05). Also, transplanted PD-MSCs enhanced antioxidants factors and organ functional restoration factors in Tx compared with NTx. These data show that PD-MSC transplantation triggers the regeneration of organ (e.g., liver and ovary) damaged by oxidative stress from TAA treatment via activating antioxidant factors. Therefore, these data suggest the therapeutic potential via antioxidant effect and help understand the therapeutic mechanism of PD-MSCs in damaged tissues such as in liver and reproductive system.