Background: Pluripotent stem cells (PSCs), including human embryonic stem cells (hESCs), hold great potential for regenerative medicine and cell therapy. One of the major hurdles hindering the clinical development of PSC-based therapy is the potential risk of tumorigenesis. CD133 (Prominin 1, PROM1) is a transmembrane protein whose mRNA and glycosylated forms are highly expressed in many human cancer cell types. CD133 also serves as a cancer stem cell (CSC) marker associated with cancer progression and patient outcome. Interestingly, CD133 is highly expressed in hESCs as well as in human preimplantation embryos, but its function in hESCs has remained largely unknown. Methods: CD133 knockout hESC WA26 cell line was generated with CRISPR/Cas9. CD133 knockout and wide type hESC lines were subjected to pluripotency, proliferation, telomere biology, and teratoma tests; the related global changes and underlying mechanisms were further systemically analyzed by RNA-seq. Results: CD133 deficiency did not affect hESC pluripotency or in vivo differentiation into three germ layers but significantly decreased cell proliferation. RNA-seq revealed that CD133 deficiency dysregulated the p53, PI3K-Akt, AMPK, and Wnt signaling pathways. Alterations in these pathways have been implicated in tumor proliferation and apoptotic escape. Conclusions: Our data imply that CD133 could be an additional target and used as a selective marker to sort and eliminate undifferentiated cells in reducing potential teratoma formation risk of hESCs in regenerative medicine.

BackgroundTelomere length heterogeneity has been detected in various cell types, including stem cells and cancer cells. Cell heterogeneity in pluripotent stem cells, such as embryonic stem cells (ESCs), is of particular interest; however, the implication and mechanisms underlying the heterogeneity remain to be understood. Single-cell analysis technology has recently been developed and effectively employed to investigate cell heterogeneity. Yet, methods that can simultaneously measure telomere length and analyze the global transcriptome in the same cell have not been available until now.ResultsWe have established a robust method that can simultaneously measure telomere length coupled with RNA-sequencing analysis (scT&R-seq) in the same human ESC (hESC). Using this method, we show that telomere length varies with pluripotency state. Compared to those with long telomere, hESCs with short telomeres exhibit the lowest expressions of TERF1/TRF1, and ZFP42/REX1, PRDM14 and NANOG markers for pluripotency, suggesting that these hESCs are prone to exit from the pluripotent state. Interestingly, hESCs ubiquitously express NOP10 and DKC1, stabilizing components of telomerase complexes. Moreover, new candidate genes, such as MELK, MSH6, and UBQLN1, are highly expressed in the cluster of cells with long telomeres and higher expression of known pluripotency markers. Notably, short telomere hESCs exhibit higher oxidative phosphorylation primed for lineage differentiation, whereas long telomere hESCs show elevated glycolysis, another key feature for pluripotency.ConclusionsTelomere length is a marker of the metabolic activity and pluripotency state of individual hESCs. Single cell analysis of telomeres and RNA-sequencing can be exploited to further understand the molecular mechanisms of telomere heterogeneity.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-017-0453-8) contains supplementary material, which is available to authorized users.

Interferon‐induced transmembrane protein 1 ( IFITM 1), a member of the IFITM protein family, is a component of a multimeric complex involved in the transduction of antiproliferation and cell adhesion signals. IFITM 1 is thought to play a role in antiproliferation and immune surveillance, and has been shown to restrict infection by numerous viruses. It is highly expressed in human embryonic stem cells ( hESC s) but its role in hESC s remains to be elucidated. In this study, knockout of IFITM 1 mediated by CRISPR /Cas9 in hESC s did not affect self‐renewal, pluripotency, telomerase activity or telomeres. However expression of human endogenous retroviruses ( HERV s) was higher than in wild‐type hESC s, and there was also a reduced level of trimethylation of histone H3 on lysine 9 at HERV loci. These data show that IFITM 1 suppresses HERV s in hESC s by regulating epigenetic modifications.

The lncRNA small nucleolar RNA host gene 1 (SNHG1) is a cerebral infarctionassociated gene, its biological role and mechanism in diabetic retinopathy remain to be illuminated. The present study was designed to investigate the role of SNHG1 in high glucose induced human retinal pigment epithelial cells (ARPE-19). Methods: ARPE-19 cells were cultured and exposed to 60 mM high glucose for 48h, and 5.5mM glucose-exposed ARPE-19 cells were used as the control. The levels of the epithelial-mesenchymal transition (EMT) markers E-cadherin, ZO-1, vimentin and α-SMA were measured, and the Cell inflammatory response was evaluated by detecting IL-6 and IL-1β levels. Then, cell migration, proliferation and apoptosis were detected. The expression of the lncRNA SNHG1 in ARPE-19 cells was detected by quantitative real-time PCR. SNHG1 was knocked down by small interfering RNA (siRNA) transfection. The effects of SNHG1 inhibition on inflammation, EMT, migration, proliferation and apoptosis were observed. Results: The results showed that the expression of SNHG1 was significantly increased in ARPE-19 cells exposed to high glucose. Silencing SNHG1 reduced the expression of vimentin, α-SMA, and the expression of inflammatory chemokines IL-6 and IL-1β, inhibited migration and proliferation, elevated the expression of E-cadherin and ZO-1, and promoted apoptosis in ARPE-19 cells. Conclusion:The lncRNA SNHG1 is involved in hyperglycemia-induced EMT and the inflammatory response of ARPE-19 cells and provides a new understanding of the pathogenesis of DR.

In addition to the improvement in BCVA and the reduction in CFT, IVR improved macular retinal function, as assessed by mf-ERG, in diabetic eyes. The combination of OCT and mf-ERG for macular evaluation may better assess DME.