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β-thalassemia is an inherited blood disease caused by reduced or inadequate β-globin synthesis due to β-globin gene mutation. Our previous study developed a gene-edited mice model (β654-ERmice) by CRISPR/Cas9-mediated genome editing, targeting both the βIVS2-654 (C > T) mutation site and the 3ʹ splicing acceptor site at 579 and corrected abnormal β-globin mRNA splicing in the β654-thalassemia mice. Herein, we further explored the therapeutic effect of the hematopoietic stem cells (HSCs) from β654-ERmice on β-thalassemia by consecutive HSC transplantation. The results indicated that HSC transplantation derived from gene-edited mice can significantly improve the survival rate of mice after lethal radiation doses and effectively achieve hematopoietic reconstruction and long-term hematopoiesis. Clinical symptoms, including hematologic parameters and tissue pathology of transplanted recipients, were significantly improved compared to the non-transplanted β654mice. The therapeutic effect of gene-edited HSC transplantation demonstrated no significant difference in hematological parameters and tissue pathology compared with wild-type mouse-derived HSCs. Our data revealed that HSC transplantation from gene-edited mice completely recovered the β-thalassemia phenotype. Our study systematically investigated the therapeutic effect of HSCs derived from β654-ERmice on β-thalassemia and further confirmed the efficacy of our gene-editing approach. Altogether, it provided a reference and primary experimental data for the clinical usage of such gene-edited HSCs in the future.Graphical Abstract

Cytosine base editors (CBEs) are effective tools for introducing C-to-T base conversions, but their clinical applications are limited by off-target and bystander effects. Through structure-guided engineering of human APOBEC3A (A3A) deaminase, we developed highly accurate A3A-CBE (haA3A-CBE) variants that efficiently generate C-to-T conversion with a narrow editing window and near-background level of DNA and RNA off-target activity, irrespective of methylation status and sequence context. The engineered deaminase domains are compatible with PAM-relaxed SpCas9-NG variant, enabling accurate correction of pathogenic mutations in homopolymeric cytosine sites through flexible positioning of the single-guide RNAs. Dual adeno-associated virus delivery of one haA3A-CBE variant to a mouse model of tyrosinemia induced up to 58.1% editing in liver tissues with minimal bystander editing, which was further reduced through single dose of lipid nanoparticle-based messenger RNA delivery of haA3A-CBEs. These results highlight the tremendous promise of haA3A-CBEs for precise genome editing to treat human diseases.

In this work, the electrical characteristics and bias stress reliability of GaN/AlN superlattices (SLs) metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) with Al2O3 dielectric are experimentally investigated. In comparison to the conventional AlGaN barrier MIS-HEMTs, the GaN/AlN SLs MIS-HEMTs exhibit a higher ON/OFF current ratio ( $10^{{{10}}}$ ), higher gate forward breakdown voltage (BV) (15.2 V) and OFF -state BV (495 V), lower ON-resistance ( $9.5~\Omega $ /mm $^{{-{1}}}$ ). Moreover, the threshold voltage ( $V_{{\text {th}}}$ ) shift and ON-resistance (R on) degradation under bias stress are further monitored. The GaN/AlN SLs MIS-HEMTs demonstrate excellent $V_{{\text {th}}}$ and $R_{{\text {on}}}$ stability, attributed to the superior dielectric/barrier interface quality and effective 2-D electron gas confinement provided by the GaN/AlN superlattice structure. These results ensure the superior performance and stability of GaN/AlN SLs MIS-HEMTs for power/RF applications.

In this article, a low-leakage-current and high-breakdown-voltage normally OFF p-GaN gate high-electron-mobility transistor (HEMT) on a Si substrate with low-damage NH3 plasma pretreatment was investigated. NH3 plasma pretreatment was performed in a plasma-enhanced chemical vapor deposition (PECVD) system before PECVD-SiNx deposition, which effectively removed surficial oxides and other impurities, suppressed the interface traps between those of SiNx and (Al)GaN, and reduced the overall drain leakage current of devices in the OFF-state. In comparison to the device without pretreatment, the normally OFF p-GaN gate HEMTs pretreated with NH3 plasma exhibited a high ON/OFF-current ratio of $10^{{9}}$ , a low reverse gate leakage current of $2.86\times 10^{-{8}}$ mA/mm, a high gate breakdown voltage of 9.1 V, and a high breakdown voltage of 690 V at $1~\mu \text{A}$ /mm. Furthermore, NH3 plasma pretreatment effectively suppressed the threshold voltage shift induced by the charge/discharge effect in p-GaN. It was found that NH3 plasma pretreatment is effective in improving device performance, such as the leakage current, breakdown voltage, and threshold voltage stability.

With the development of intelligent technologies, Internet of Things (IoT) opens up a new era in the field of automotive networks, namely, Internet of Vehicles (IoV). The main goal of IoV is to provide a secure and reliable network to vehicles so that users can enjoy various services. However, vulnerabilities and incomplete protection mechanisms have led to a proliferation of security threats against IoV networks. Intrusion detection technology is an effective protection solution for IoV security, especially when artificial intelligence (AI) technology has been introduced into intrusion detection study. This article first briefly introduces the concept and features of IoV, and then reviews the related research on AI-based IoV intrusion detection systems. Finally, we discuss the open challenges and future research directions.

G protein-coupled receptors (GPCRs) are the largest family of transmembrane receptors and regulate various physiological and pathological processes. Despite extensive studies, the roles of GPCRs in mouse embryonic stem cells (mESCs) represent a significant data gap. Here, we show that GPR160, a class A member of GPCRs, is dramatically downregulated concurrent with mESC differentiation into embryoid bodies in vitro. Knockdown of GPR160leads to downregulation of the expression of pluripotency-associated transcription factors and upregulation of the expression of lineage markers, accompanying with the arrest of the mESC cell cycle in the G0/G1 phase. RNA-seq analysis shows that GPR160 participates in the JAK/STAT signaling pathway crucial for maintaining ESC stemness, and the knockdown of GPR160results in the downregulation of STAT3 phosphorylation level, which in turn is partially rescued by colivelin, a STAT3 activator. Constant with these observations, GPR160 physically interacts with JAK1, and cooperates with leukemia inhibitory factor receptor (LIFR) and gp130 to activate the STAT3 pathway. In summary, our results suggest that GPR160 regulates mESC self-renewal and pluripotency by interacting with the JAK1-LIFR-gp130 complex to mediate the JAK1/STAT3 signaling pathway.

This article summarizes the recent activity of the International Stem Cell Banking Initiative (ISCBI) held at the California Institute for Regenerative Medicine (CIRM) in California (June 26, 2016) and the Korean National Institutes for Health in Korea (October 19–20, 2016). Through the workshops, ISCBI is endeavoring to support a new paradigm for human medicine using pluripotent stem cells (hPSC) for cell therapies. Priority considerations for ISCBI include ensuring the safety and efficacy of a final cell therapy product and quality assured source materials, such as stem cells and primary donor cells. To these ends, ISCBI aims to promote global harmonization on quality and safety control of stem cells for research and the development of starting materials for cell therapies, with regular workshops involving hPSC banking centers, biologists, and regulatory bodies. Here, we provide a brief overview of two such recent activities, with summaries of key issues raised. StemCellsTranslationalMedicine2017;6:1956–1962 This article reviews recent discussions among world leading groups working on provision of stem cell lines for research and clinical use. ISCBI confirmed the need for standards of quality control, safety, ethics, and resource sharing.

Cryopreservation techniques for mammalian oocytes and embryos have rapidly progressed during the past two decades, emphasizing their importance in various assisted reproductive technologies. Pregnancies and live births resulting from cryopreserved oocytes and embryos of several species including humans have provided proof of principle and led to the adoption of cryopreservation as an integral part of clinical in vitrofertilization. Considerable progress has been achieved in the development and application of the cryopreservation of mammalian oocytes and embryos, including preservation of the reproductive potential of patients who may become infertile, establishment of cryopreserved oocyte banks, and transport of oocytes and embryos internationally. However, the success rates are still far lower than those obtained with fresh oocytes and embryos, and there are still obstacles that need to be overcome. In this review, we address the major obstacles in the development of effective cryopreservation techniques. Such knowledge may help to eliminate these hurdles by revealing which aspects need improvement. Furthermore, this information may encourage further research by cryobiologists and increase the practical use of cryopreservation as a major part of assisted reproductive technologies for both humans and animal species.

Human mitochondrial DNA is a circular DNA molecule that encodes some of the proteins required for oxidative phosphorylation. Different mitochondrial DNA genotypes may coexist within a single cell, a condition known as heteroplasmy. An A-to-G transition at position 3243 of mitochondrial DNA (A3243G) can result in maternally inherited diabetes and deafness (mitochondrial diabetes). However, the commonly used methods of PCR restriction fragment length polymorphism and Sanger sequencing are neither sensitive nor reliable enough to detect this low level of heteroplasmy. Here, we developed a quantitative method based on pyrosequencing to analyze the heteroplasmy of the A3243G mutation in leukocyte DNA obtained from 83 persons of 15 unrelated pedigrees with mitochondrial diabetes. The accuracy and reliability of this method were also measured by comparing the results with those from high-resolution melting analysis, Sanger sequencing, and PCR restriction fragment length polymorphism with artificial heteroplasmy standard samples. The results showed that the accuracy of pyrosequencing was much higher than that of the other methods, and the limitation of heteroplasmy detection with this method reached 2%, based on our artificial control studies. An inverse correlation was found between the level of heteroplasmy and the age of the onset in our patients. This result suggested that the heteroplasmy of the A3243G mutation could become a significant prediction index for the onset of mitochondrial diabetes.

Data sharing is an essential element of research; however, recent scientific and social developments have challenged conventional methods for protecting privacy. Here we provide guidance for determining data sharing thresholds for human pluripotent stem cell research aimed at a wide range of stakeholders, including research consortia, biorepositories, policy-makers, and funders.

Induced pluripotent stem (iPS) cells can be generated from mouse or human fibroblasts by exogenous expression of four factors, Oct4, Sox2, Klf4 and c-Myc, and hold great potential for transplantation therapies and regenerative medicine. However, use of retroviral vectors during iPS cell generation has limited the technique’s clinical application due to the potential risks resulting from genome integration of transgenes, including insertional mutations and altered differentiation potentials of the target cells, which may lead to pathologies such as tumorigenesis. Here we review recent progress in generating safer transgene-free or integration-free iPS cells, including the use of non-integrating vectors, excision of vectors after integration, DNA-free delivery of factors and chemical induction of pluripotency.

Induced pluripotent stem (iPS) cells can be generated from mouse or human fibroblasts by exogenous expression of four factors, Oct4, Sox2, Klf4 and c-Myc, and hold great potential for transplantation therapies and regenerative medicine. However, use of retroviral vectors during iPS cell generation has limited the technique’s clinical application due to the potential risks resulting from genome integration of transgenes, including insertional mutations and altered differentiation potentials of the target cells, which may lead to pathologies such as tumorigenesis. Here we review recent progress in generating safer transgene-free or integration-free iPS cells, including the use of non-integrating vectors, excision of vectors after integration, DNA-free delivery of factors and chemical induction of pluripotency.

Special education teacher (SET) burnout is a significant concern, especially for SETs serving students with emotional–behavioral disorders (EBD), as they tend to experience higher burnout than other teachers. Working conditions, especially social support, have the potential to ameliorate burnout, but prior research has not articulated the sources and types of social support that are most important. The authors conducted a longitudinal study, surveying 230 SETs serving students with EBD at three time points across 1 school year. Data revealed administrative support, adequacy of planning time, and autonomy in fall predicted emotional exhaustion and personal accomplishment in winter and spring. Associations between working conditions and burnout components were partially mediated by SETs’ perceptions of workload manageability. SET change in well-being due to COVID-19 during the early months of the pandemic was not associated with burnout. The authors discuss implications, limitations, and directions for future inquiry.

The liver is the largest internal organ in mammals, and is important for the maintenance of normal physiological functions of other tissues and organs. Hepatitis, cirrhosis, liver cancer and other chronic liver diseases are serious threats to human health, and these problems are compounded by a scarcity of liver donors for transplantation therapies. Directed differentiation of embryonic stem cells to liver cells is a promising strategy for obtaining hepatocytes that can be used for cell transplantation. In vitrohepatocyte differentiation of embryonic stem cells requires a profound understanding of normal development during embryonic hepatogenesis. Here we provide a simple description of hepatogenesis in vivoand discuss directed differentiation of embryonic stem cells into hepatocytes in vitro.

Induced pluripotent stem cells (iPSCs) are considered to be an attractive alternative to embryonic stem cells (ESCs) and may provide great potential for clinical applications in regenerative medicine. Although possessing characteristics similar to ESCs, the true pluripotency of these newly studied iPSCs was not known because none of the previously developed iPSCs passed the tetraploid complementation assay, which is regarded as the most stringent test for pluripotency. We have recently shown that by modifying some of the culture conditions for inducing iPSCs, we were able to generate cell lines of high pluripotency, resulting in the production of live-born, fertile animals through tetraploid complementation. In this paper, we describe details of our methods of generating iPS cell lines and subsequently producing full-term live animals through the tetraploid complementation assay; the procedure can be completed within 2 months.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, an X-linked inherited disease, is one of the most common enzymopathies and affects over 400 million people worldwide. In China at least 21 distinct point mutations have been identified so far. In this study high-resolution melting (HRM) analysis was used to screen for G6PD mutations in 260 unrelated Han Chinese individuals, and the rapidity and reliability of this method was investigated. The mutants were readily differentiated by using HRM analysis, which produced distinct melting curves for each tested mutation. Interestingly, G1388A and G1376T, the two most common variants accounting for 50% to 60% of G6PD deficiency mutations in the Chinese population, could be differentiated in a single reaction. Further, two G6PD mutations not previously reported in the Chinese population were identified in this study. One of these mutations, designated “G6PD Jiangxi G1340T,” involved a G1340T substitution in exon 11, predicting a Gly447Val change in the protein. The other mutation involved a C406T substitution in exon 5. The frequencies of the common polymorphism site C1311T/IVS (intervening sequence) XI t93c between patients with G6PD and healthy volunteers were not significantly different. Thus, HRM analysis will be a useful alternative for screening G6PDmutations.

Immunoprecipitation of mRNA-protein complexes is a method that can be used to study RNA binding protein (RBP)–RNA interactions. In this protocol, an antibody targeting an RBP of interest is used to immunoprecipitate the RBP and any interacting molecules from a cell lysate. Reverse transcription followed by PCR is then used to identify individual mRNAs isolated with the RBP. This method focuses on examining an association between a specific RBP-mRNA complex, and it is best suited for a small scale screening of known or putative binding partners. It can also be used as a second, independent method to verify RBP-mRNA interactions discovered through more universal screening techniques. We describe the immunoprecipitation protocol in practical detail and discuss variations of the method as well as issues associated with it. The procedure takes three days to complete.

The paucity of biological material has inhibited identifying genes that are differentially expressed during mammalian oogenesis and preimplantation development. We report here the linear amplification of mRNA from small numbers of mouse oocytes and preimplantation embryos to generate amounts of sense RNA that are sufficient for suppression subtractive hybridization. The resulting oocyte-specific and 8-cell-specific cDNA libraries were partially characterized, and the known oocyte-specific ZP1, ZP2, GDF-9, BMP15, and H1oogenes were found in the oocyte-specific cDNA library but not in the 8-cell-specific library. Further characterization of the subtracted oocyte and 8-cell embryo cDNA libraries should furnish a trove of information regarding temporal changes in gene expression during oogenesis and preimplantation development in the mouse.

No relevant conflicts of interest to declare.

Abstract 3265