Self-renewing human naïve pluripotent stem cells dedifferentiate in 3D culture and form blastoids spontaneously.

Human naïve pluripotent stem cells (hnPSCs) can generate integrated models of blastocysts termed blastoids upon switch to inductive medium. However, the underlying mechanisms remain obscure. Here we report that self-renewing hnPSCs spontaneously and efficiently give rise to blastoids upon three dimensional (3D) suspension culture. The spontaneous blastoids mimic early stage human blastocysts in terms of structure, size, and transcriptome characteristics and are capable of progressing to post-implantation stages. This property is conferred by the glycogen synthase kinase-3 (GSK3) signalling inhibitor IM-12 present in 5iLAF self-renewing medium. IM-12 upregulates oxidative phosphorylation-associated genes that underly the capacity of hnPSCs to generate blastoids spontaneously. Starting from day one of self-organization, hnPSCs at the boundary of all 3D aggregates dedifferentiate into E5 embryo-like intermediates. Intermediates co-express SOX2/OCT4 and GATA6 and by day 3 specify trophoblast fate, which coincides with cavity and blastoid formation. In summary, spontaneous blastoid formation results from 3D culture triggering dedifferentiation of hnPSCs into earlier embryo-like intermediates which are then competent to segregate blastocyst fates.

In vitro generation of mouse morula-like cells.

Generating cells with the molecular and functional properties of embryo cells and with full developmental potential is an aim with fundamental biological significance. Here we report the in vitro generation of mouse transient morula-like cells (MLCs) via the manipulation of signaling pathways. MLCs are molecularly distinct from embryonic stem cells (ESCs) and cluster instead with embryo 8- to 16-cell stage cells. A single MLC can generate a blastoid, and the efficiency increases to 80% when 8-10 MLCs are used. MLCs make embryoids directly, efficiently, and within 4 days. Transcriptomic analysis shows that day 4-5 MLC-derived embryoids contain the cell types found in natural embryos at early gastrulation. Furthermore, MLCs introduced into morulae segregate into epiblast (EPI), primitive endoderm (PrE), and trophectoderm (TE) fates in blastocyst chimeras and have a molecular signature indistinguishable from that of host embryo cells. These findings represent the generation of cells that are molecularly and functionally similar to the precursors of the first three cell lineages of the embryo.

Isolation, identification, and pathogenicity of a NADC30-like porcine reproductive and respiratory disorder syndrome virus strain affecting sow production.

Since it was first reported in 1987, porcine reproductive and respiratory syndrome virus (PRRSV) has caused several economic crises worldwide. The current prevalence of PRRSV NADC30-like stains causing clinical disease outbreaks in Chain is highly concerning. Immunization against and the prevention of this infection are burdensome for farming organizations as the pathogen frequently mutates and undergoes recombination. Herein, the genetic characterization of a NADC30-like strain (termed BL2019) isolated from a farm in Guangdong Province, China, was analyzed and its pathogenicity for piglets and sows was assessed. Results revealed that BL2019 exhibits a nucleotide homology of 93.7% with NADC30 PRRSV and its NSP2 coding region demonstrates the same 131aa deletion pattern as that of NADC30 and NADC30-like. Furthermore, we identified two recombination breakpoints located nt5804 of the NSP5-coding region and nt6478 of NSP2-coding region, the gene fragment between the two breakpoints showed higher homology to the TJ strain(a representative strain of highly pathogenic PRRSV) compared to the NADC30 strain. In addition, BL2019 infection in piglets caused fever lasting for 1 week, moderate respiratory clinical signs and obvious visual and microscopic lung lesions; infection in gestating sows affected their feed intake and increased body temperature, abortion rates, number of weak fetuses, and other undesirable phenomena. Therefore, we report a NADC30-like PRRSV strain with partial recombination and a representative strain of HP-PRRSV, strain TJ, that can provide early warning and support for PRRS immune prevention and control.

Multiplexed single-cell transcriptome analysis reveals molecular characteristics of monkey pluripotent stem cell lines. / åˆ©ç”¨å¤šæ ·å“æ ‡è®°å•ç»†èƒžè½¬å½•ç»„åˆ†æžæŠ€æœ¯è¡¨å¾çŒ´å¤šèƒ½å¹²ç»†èƒž.

Efforts have been made to establish various human pluripotent stem cell lines. However, such methods have not yet been duplicated in non-human primate cells. Here, we introduce a multiplexed single-cell sequencing technique to profile the molecular features of monkey pluripotent stem cells in published culture conditions. The results demonstrate suboptimized maintenance of pluripotency and show that the selected signaling pathways for resetting human stem cells can also be interpreted for establishing monkey cell lines. Overall, this work legitimates the translation of novel human cell line culture conditions to monkey cells and provides guidance for exploring chemical cocktails for monkey stem cell line derivation.

Palladium-Catalyzed gem-Difluoroallylation Reaction between Aryltributyltin and Bromodifluoromethylated Alkenes.

A robust Stille gem-difluoroallylation of arylstannanes with 3-bromo-3,3-difluoropropenes has been established. The catalyst was found to exert critical effect on the reaction chemoselectivity. By using Pd(OH)2/C as the catalyst, a series of 3-(hetero)aryl/vinyl-3,3-difluoropropenes were obtained in high efficiency with α-substitution regioselectivity. The reaction has a broad substrate scope, and various substitution patterns were well tolerated in both substrates. Notably, the reaction can be easily extended to late-stage gem-difluoroallylation of many bioactive molecules with good chemoselectivity.

Two Birds with One Stone: Preparation of 4, 4-Diaminodiphenylmethane Functionalized GO@SiO2 with Mechanical Reinforcement and UV Shielding Properties and Its Application in Thermoplastic Polyurethane.

This study prepared 4,4-diaminodiphenylmethane (DDM)-functionalized graphene oxide (GO)@silica dioxide (SiO2) nano-composites through amidation reaction and low-temperature precipitation. The resulting modified GO, that was DDM-GO@SiO2. The study found that DDM-GO@SiO2 showed good dispersion and compatibility with thermoplastic polyurethane (TPU) substrates. Compared with pure TPU, the tensile strength of the TPU composites increased by 41% to 94.6 MPa at only 0.5 wt% DDM-GO@SiO2. In addition, even when a small amount of DDM-GO@SiO2 was added, the UV absorption of TPU composites increased significantly, TPU composites can achieve a UV shielding efficiency of 95.21% in the UV-A region. These results show that this type of material holds great promise for the preparation of functional coatings and film materials with high strength and weather resistance.

Generation of pancreatic progenitors from human pluripotent stem cells by small molecules.

Human pluripotent stem cell (hPSC)-derived pancreatic progenitors (PPs) provide promising cell therapies for type 1 diabetes. Current PP differentiation requires a high amount of Activin A during the definitive endoderm (DE) stage, making it economically difficult for commercial ventures. Here we identify a dose-dependent role for Wnt signaling in controlling DE differentiation without Activin A. While high-level Wnt activation induces mesodermal formation, low-level Wnt activation by a small-molecule inhibitor of glycogen synthase kinase 3 is sufficient for DE differentiation, yielding SOX17+FOXA2+ DE cells. BMP inhibition further enhances this DE differentiation, generating over 87% DE cells. These DE cells could be further differentiated into PPs and functional ß cells. RNA-sequencing analysis of PP differentiation from hPSCs revealed expected transcriptome dynamics and new gene regulators during our small-molecule PP differentiation protocol. Overall, we established a robust growth-factor-free protocol for generating DE and PP cells, facilitating scalable production of pancreatic cells for regenerative applications.

Primate Organoids and Gene-Editing Technologies toward Next-Generation Biomedical Research.

The improved ability to organize pluripotent stem cells (PSCs) into 3D structures in vitro has shed light on organoid technology to recapitulate organs and tumors in vivo. Advances in gene-editing technologies, particularly CRISPR-mediated techniques, offer tremendous potential in facilitating organoid research, including the study of development, disease modeling, and personalized medicine. This review discusses how the combination of two novel technologies - organoids and gene editing - not only contributes to revealing molecular events taking place during development and tumorigenesis but also has implications for biobanking, precision medicine, and other diverse biomedical applications.

Association Between Aspirin Use and Risk of Aneurysmal Subarachnoid Hemorrhage: A Meta-analysis.

OBJECTIVE: To assess the association between aspirin use and risk of aneurysmal subarachnoid hemorrhage (aSAH). METHODS: A systematic search was performed in various databases updated on October 22, 2019. The heterogeneity test was performed for each outcome variable. Random-effect model and fixed-effect model were respectively conducted according to the heterogeneity statistics. Trial sequential analysis was used to control random errors. RESULTS: Ten studies involving 1,107,616 patients were involved in this meta-analysis. No significant association was shown between aspirin users and non-aspirin users regarding the risk of aSAH (odds ratio [OR]: 0.981, 95% confidential interval [CI]: 0.773-1.312, P = 0.897]. The results of subgroup analyses indicated that the risk of aSAH was notably associated with a short-term use of aspirin (<3 months) (OR: 1.697, 95% CI: 1.175-2.452, P = 0.005), but not aspirin use for 3-12 months (OR: 1.026, 95% CI: 0.609-1.730, P = 0.922), 1-3 years (OR: 0.942, 95% CI: 0.660-1.346, P = 0.744), >3 years (OR: 0.892, 95% CI: 0.573-1.389, P = 0.612), ≤2 times per week (OR: 0.857, 95% CI: 0.560-1.313, P = 0.479), ≥3 times per week (OR: 1.104, 95% CI: 0.555-2.193, P = 0.778) and former use (OR: 1.029, 95% CI: 0.482-2.196, P = 0.941). CONCLUSIONS: A short-term use of aspirin (<3 months) is associated with an elevated risk of aSAH, whereas the role of its long-term use in either decreasing or increasing the risk of aSAH still requires well-designed, large-scale randomized control trials for verification.

Biomaterials for stem cell engineering and biomanufacturing.

Recent years have witnessed the expansion of tissue failures and diseases. The uprising of regenerative medicine converges the sight onto stem cell-biomaterial based therapy. Tissue engineering and regenerative medicine proposes the strategy of constructing spatially, mechanically, chemically and biologically designed biomaterials for stem cells to grow and differentiate. Therefore, this paper summarized the basic properties of embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs) and adult stem cells. The properties of frequently used biomaterials were also described in terms of natural and synthetic origins. Particularly, the combination of stem cells and biomaterials for tissue repair applications was reviewed in terms of nervous, cardiovascular, pancreatic, hematopoietic and musculoskeletal system. Finally, stem-cell-related biomanufacturing was envisioned and the novel biofabrication technologies were discussed, enlightening a promising route for the future advancement of large-scale stem cell-biomaterial based therapeutic manufacturing.

An Ultrasensitive Calcium Reporter System via CRISPR-Cas9-Mediated Genome Editing in Human Pluripotent Stem Cells.

Genetically encoded calcium indicator (GCaMP) proteins have been reported for imaging cardiac cell activity based on intracellular calcium transients. To bring human pluripotent stem cell (hPSC)-derived cardiomyocytes (CMs) to the clinic, it is critical to evaluate the functionality of CMs. Here, we show that GCaMP6s-expressing hPSCs can be generated and used for CM characterization. By leveraging CRISPR-Cas9 genome editing tools, we generated a knockin cell line that constitutively expresses GCaMP6s, an ultrasensitive calcium sensor protein. We further showed that this clone maintained pluripotency and cardiac differentiation potential. These knockin hPSC-derived CMs exhibited sensitive fluorescence fluctuation with spontaneous contraction. We then compared the fluorescence signal with mechanical contraction signal. The knockin hPSC-derived CMs also showed sensitive response to isoprenaline treatment in a concentration-dependent manner. Therefore, the GCaMP6s knockin hPSC line provides a non-invasive, sensitive, and economic approach to characterize the functionality of hPSC-derived CMs.

Clinical observation on hearing conditions of centenarians in northern district of China.

CONCLUSION: The hearing conditions of the centenarians were quite poor as regards hearing thresholds and speech detection ability. OBJECTIVE: To investigate hearing conditions of centenarians. METHODS: A total of 54 centenarians in Rizhao and Linyi Districts in Shandong Province were investigated to assess hearing conditions of centenerians comprehensively by questionnaire investigation, pure-tone audiometry, acoustic immitance, intelligence evaluation, and speech detection scores. Also, 135 individuals were recruited as controls and divided into four groups according to their age: 45-59 years, 60-69 years, 70-79 years, and 80-89 years. RESULTS: The hearing thresholds of the centenarians were dramatically higher than those of the control group (p < 0.05) and all centenarians suffered moderate to profound hearing loss according to the World Health Organization (WHO) criteria. Few centenarians had normal level of speech detection scores. All centenarians showed descending hearing curve, and the hearing threshold of the male centenarians at 8000 Hz was higher than that of the females (p = 0.047). There was a significant air-bone conduction gap in the centenarians (p < 0.05).