Genome editing HLA alleles for a pilot immunocompatible hESC line in a Chinese hESC bank for cell therapies.

Robust allogeneic immune reactions after transplantation impede the translational pace of human embryonic stem cells (hESCs)-based therapies. Selective genetic editing of human leucocyte antigen (HLA) molecules has been proposed to generate hESCs with immunocompatibility, which, however, has not been specifically designed for the Chinese population yet. Herein, we explored the possibility of customizing immunocompatible hESCs based on Chinese HLA typing characteristics. We generated an immunocompatible hESC line by disrupting HLA-B, HLA-C, and CIITA genes while retaining HLA-A*11:01 (HLA-A*11:01-retained, HLA-A11R ), which covers ~21% of the Chinese population. The immunocompatibility of HLA-A11R hESCs was verified by in vitro co-culture and confirmed in humanized mice with established human immunity. Moreover, we precisely knocked an inducible caspase-9 suicide cassette into HLA-A11R hESCs (iC9-HLA-A11R ) to promote safety. Compared with wide-type hESCs, HLA-A11R hESC-derived endothelial cells elicited much weaker immune responses to human HLA-A11+ T cells, while maintaining HLA-I molecule-mediated inhibitory signals to natural killer (NK) cells. Additionally, iC9-HLA-A11R hESCs could be induced to undergo apoptosis efficiently by AP1903. Both cell lines displayed genomic integrity and low risks of off-target effects. In conclusion, we customized a pilot immunocompatible hESC cell line based on Chinese HLA typing characteristics with safety insurance. This approach provides a basis for establishment of a universal HLA-AR bank of hESCs covering broad populations worldwide and may speed up the clinical application of hESC-based therapies.

A sustainable mouse karyotype created by programmed chromosome fusion.

Chromosome engineering has been attempted successfully in yeast but remains challenging in higher eukaryotes, including mammals. Here, we report programmed chromosome ligation in mice that resulted in the creation of new karyotypes in the lab. Using haploid embryonic stem cells and gene editing, we fused the two largest mouse chromosomes, chromosomes 1 and 2, and two medium-size chromosomes, chromosomes 4 and 5. Chromatin conformation and stem cell differentiation were minimally affected. However, karyotypes carrying fused chromosomes 1 and 2 resulted in arrested mitosis, polyploidization, and embryonic lethality, whereas a smaller fused chromosome composed of chromosomes 4 and 5 was able to be passed on to homozygous offspring. Our results suggest the feasibility of chromosome-level engineering in mammals.

Relationship between risk perception of COVID-19 and job withdrawal among Chinese nurses: The effect of work-family conflict and job autonomy.

AIM: The aim of this study was to examine the mediating role of work-family conflict and the moderating role of job autonomy on the association between risk perception of COVID-19 and job withdrawal among Chinese nurses during the initial disease outbreak. BACKGROUND: Nurses' job withdrawal can not only reduce the quality and efficiency of care but also give rise to turnover during the COVID-19 pandemic. Thus, it is essential to clarify how and when the risk perception of COVID-19 influences the job withdrawal behaviours of nurses and to provide guidelines for reducing nurses' job withdrawal. METHODS: A two-wave study was conducted among 287 Chinese nurses from 11 COVID-19-designated hospitals during the initial outbreak of the disease from March through April 2020. Data on the risk perception of COVID-19, job autonomy and work-family conflict were collected at time 1, and 1 month later, job withdrawal data were collected at time 2. Model 4 and Model 14 from SPSS macro PROCESS were used to test the mediating effect of work-family conflict and the moderating effect of job autonomy, respectively. RESULTS: Work-family conflict mediated 60.54% of the relationship between risk perception of COVID-19 and job withdrawal. Job autonomy positively moderated the relation between work-family conflict and job withdrawal (ß = 0.12, P < 0.01). CONCLUSION: Risk perception of COVID-19 influenced nurses' job withdrawal through work-family conflict. Job autonomy exaggerated the association between work-family conflict and job withdrawal. IMPLICATIONS FOR NURSING MANAGEMENT: Managers should provide more supportive resources to help nurses cope with the risk of COVID-19 to decrease work-family conflict and job withdrawal, and they should strengthen supervision over the work processes of nurses.

Pathogenesis and Treatment of Cytokine Storm Induced by Infectious Diseases.

Cytokine storm is a phenomenon characterized by strong elevated circulating cytokines that most often occur after an overreactive immune system is activated by an acute systemic infection. A variety of cells participate in cytokine storm induction and progression, with profiles of cytokines released during cytokine storm varying from disease to disease. This review focuses on pathophysiological mechanisms underlying cytokine storm induction and progression induced by pathogenic invasive infectious diseases. Strategies for targeted treatment of various types of infection-induced cytokine storms are described from both host and pathogen perspectives. In summary, current studies indicate that cytokine storm-targeted therapies can effectively alleviate tissue damage while promoting the clearance of invading pathogens. Based on this premise, "multi-omics" immune system profiling should facilitate the development of more effective therapeutic strategies to alleviate cytokine storms caused by various diseases.

A microfluidic platform utilizing anchored water-in-oil-in-water double emulsions to create a niche for analyzing single non-adherent cells.

Non-adherent cells play key roles in various biological processes. Studies on this type of cell, especially at single-cell resolution, help reveal molecular mechanisms underlying many biological and pathological processes. The emerging microfluidics technology has developed effective methods for analyzing cells. However, it remains challenging to treat and monitor single live non-adherent cells in an in situ, long-term, and real-time manner. Herein, a microfluidic platform was set up to generate and anchor cell-laden water-in-oil-in-water (W/O/W) double emulsions (DEs) to investigate these cells. Within the device, W/O/W DEs encapsulating non-adherent cells were generated through two adjacent flow-focusing structures and subsequently anchored in an array of microchambers. These droplets maintained the W/O/W structure and the anchorage status in the continuous perfusion fluid for at least one week. The mass transfer of different molecules with suitable molecular weights and partition coefficients between the interior and exterior of W/O/W DEs could be regulated by perfusion fluid flow rates. These features endow this platform with potential to continuously supply encapsulated non-adherent cells with nutrients or small-molecule stimuli/drugs through fluid perfusion. Meanwhile, the confinement of cells in the anchored DEs favored long-term monitoring of cellular dynamic behaviors and responses. As a proof of concept, fluorescein diacetate (FDA) was employed to visualize the cellular uptake and biochemical metabolism of TF-1 human erythroleukemia cells. We believe that this W/O/W DE anchorage and perfusion platform would benefit single-cell-level studies as well as small-molecule drug discovery requiring live non-adherent cells.