技术资料

Gene-of-interest knockout organoids present a powerful and versatile research tool to study a gene's effects on many biological and pathological processes. Here,we present a straightforward and broadly applicable protocol to generate gene knockouts in mouse organoids using CRISPR-Cas9 technology. We describe the processes of transient transfecting organoids with pre-assembled CRISPR-Cas9 ribonucleoprotein complexes,organoid cell sorting,and establishing clonal organoid culture pairs. We then detail how to confirm the knockout via Western blot analysis. View Publication

Microtubule-associated protein (MAP) 2 has been perceived as a static cytoskeletal protein enriched in neuronal dendritic shafts. Emerging evidence indicates dynamic functions for various MAPs in activity-dependent synaptic plasticity. However,it is unclear how MAP2 is associated with synaptic plasticity mechanisms. Here,we demonstrate that specific silencing of high-molecular-weight MAP2 in vivo abolished induction of long-term potentiation (LTP) in the Schaffer collateral pathway of CA1 pyramidal neurons and in vitro blocked LTP-induced surface delivery of AMPA receptors and spine enlargement. In mature hippocampal neurons,we observed rapid translocation of a subpopulation of MAP2,present in dendritic shafts,to spines following LTP stimulation. Time-lapse confocal imaging showed that spine translocation of MAP2 was coupled with LTP-induced spine enlargement. Consistently,immunogold electron microscopy revealed that LTP stimulation of the Schaffer collateral pathway promoted MAP2 labeling in spine heads of CA1 neurons. This translocation depended on NMDA receptor activation and Ras-MAPK signaling. Furthermore,LTP stimulation led to an increase in surface-expressed AMPA receptors specifically in the neurons with MAP2 spine translocation. Altogether,this study indicates a novel role for MAP2 in LTP mechanisms and suggests that MAP2 participates in activity-dependent synaptic plasticity in mature hippocampal networks. View Publication

Three-dimensional (3D) culture systems have been developed that can re-capitulate organ level responses,simulate compound diffusion through complex structures,and assess cellular heterogeneity of tissues,making them attractive models for advanced in vitro research and discovery. Organoids are a unique subtype of 3D cell culture that are grown from stem cells,are self-organizing,and closely replicate in vivo pathophysiology. Organoids have been used to understand tissue development,model diseases,test drug sensitivity and toxicity,and advance regenerative medicine. However,traditional organoid culture methods are inadequate because they are low throughput and ill-suited for single organoid imaging,phenotypic assessment,and isolation from heterogenous organoid populations. To address these bottlenecks,we have adapted our tissue culture consumable and instrumentation to enable automated imaging,identification,and isolation of individual organoids. Organoids grown on the 3D CytoSort? Array can be reliably tracked,imaged,and phenotypically analyzed using brightfield and fluorescent microscopy as they grow over time,then released and transferred fully intact for use in downstream applications. Using mouse hepatic and pancreatic organoids,we have demonstrated the use of this technology for single-organoid imaging,clonal organoid generation,parent organoid subcloning,and single-organoid RNA extraction for downstream gene expression or transcriptomic analysis. The results validate the ability of the CellRaft AIR? System to facilitate efficient,user-friendly,and automated workflows broadly applicable to organoid research by overcoming several pain points: 1) single organoid time-course imaging and phenotypic assessment,2) establishment of single cell-derived organoids,and 3) isolation and retrieval of single organoids for downstream applications. View Publication

BACKGROUND Circular RNA of vimentin (circ-VIM) is a predictor for poor prognosis of acute myeloid leukemia,but we had little information on its function in esophageal cancer (EC). Here we examined the effects of circ-VIM together with sevoflurane on immune escape and multiple oncogenic activities of EC. METHODS Bioinformatic tools,luciferase assay,and RNA immunoprecipitation were used to examine regulations between circ-VIM,miR-124-3p (miR-124),and PD-L1. CCK-8,wound healing,and Transwell assays were used to measure cell proliferation,migration,and invasion,respectively. The impacts of EC cells on cytotoxicity,proliferation,and apoptosis of CD8+ T cells were examined using LDH assay,CFSE staining,and Annexin V/PI staining,respectively. The in vivo tumorigenesis and lung metastases were assessed using xenograft model and tail vein injection of EC cells. RESULTS Significant upregulation of circ-VIM and PD-L1 and downregulation of miR-124 were detected in EC tissues or cells. Circ-VIM sponged miR-124 and released its suppression on the downstream target PD-L1. Sevoflurane,independent of circ-VIM,also upregulated miR-124 to lower PD-L1 expression. By modulating miR-124/PD-L1 axis,silencing circ-VIM and applying sevoflurane both inhibited immune escape and multiple oncogenic activities of EC in vitro,and suppressed xenograft growth and lung metastases in vivo. The inactivation of Ras/ERK signaling pathway was involved in suppression of malignant phenotypes by silencing circ-VIM and sevoflurane treatment. CONCLUSIONS Silencing circ-VIM and applying sevoflurane,by separately regulating miR-124/PD-L1 axis,presented synergistic effects in inhibiting immune escape and multiple malignant phenotypes of EC cells. View Publication

AIMS Whereas intravenous administration of Toll-like receptor 4 ligand lipopolysaccharide (LPS) to human volunteers is frequently used in clinical pharmacology studies,systemic use of LPS has practical limitations. We aimed to characterize the intradermal LPS response in healthy volunteers,and as such qualify the method as local inflammation model for clinical pharmacology studies. METHODS Eighteen healthy male volunteers received 2 or 4 intradermal 5 ng LPS injections and 1 saline injection on the forearms. The LPS response was evaluated by noninvasive (perfusion,skin temperature and erythema) and invasive assessments (cellular and cytokine responses) in skin biopsy and blister exudate. RESULTS LPS elicited a visible response and returned to baseline at 48??hours. Erythema,perfusion and temperature were statistically significant (P  View Publication

Understanding human hematopoietic stem cell fate control is important for its improved therapeutic manipulation. Asymmetric cell division,the asymmetric inheritance of factors during division instructing future daughter cell fates,was recently described in mouse blood stem cells. In human blood stem cells,the possible existence of asymmetric cell division remained unclear because of technical challenges in its direct observation. Here,we use long-term quantitative single-cell imaging to show that lysosomes and active mitochondria are asymmetrically inherited in human blood stem cells and that their inheritance is a coordinated,nonrandom process. Furthermore,multiple additional organelles,including autophagosomes,mitophagosomes,autolysosomes,and recycling endosomes,show preferential asymmetric cosegregation with lysosomes. Importantly,asymmetric lysosomal inheritance predicts future asymmetric daughter cell-cycle length,differentiation,and stem cell marker expression,whereas asymmetric inheritance of active mitochondria correlates with daughter metabolic activity. Hence,human hematopoietic stem cell fates are regulated by asymmetric cell division,with both mechanistic evolutionary conservation and differences to the mouse system. View Publication

Resting CD4+ T cells are primary targets of early HIV infection events in vivo,but do not readily support HIV replication in vitro. This barrier to infection can be overcome by exposing resting CD4+ T cells to endothelial cells (ECs). ECs line blood vessels and direct T cell trafficking into inflamed tissues. Cell trafficking pathways have been shown to have overlapping roles in facilitating HIV replication,but their relevance to EC-mediated enhancement of HIV susceptibility in resting CD4+ T cells has not previously been examined. We characterized the phenotype of primary human resting CD4+ T cells that became productively infected with HIV when cocultured with primary human blood and lymphatic ECs. The infected CD4+ T cells were primarily central memory cells enriched for high expression of the integrins LFA-1 and VLA-4. ICAM-1 and VCAM-1,the cognate ligands for LFA-1 and VLA-4,respectively,were expressed by the ECs in the coculture. Blocking LFA-1 and VLA-4 on resting CD4+ T cells inhibited infection by 65.4%-96.9%,indicating that engagement of these integrins facilitates EC-mediated enhancement of productive HIV infection in resting CD4+ T cells. The demonstration that ECs influence cellular HIV susceptibility of resting memory CD4+ T cells through cell trafficking pathways engaged during the transmigration of T cells into tissues highlights the physiological relevance of these findings for HIV acquisition and opportunities for intervention. View Publication

Persistent inflammation is a major contributor to healing impairment in diabetic chronic wounds. Paradoxically,diabetic wound environment during the acute phase of healing is completely different because it exhibits a reduced macrophage response owing to inadequate expression of CCL2 proinflammatory cytokine. What causes a reduction in CCL2 expression in diabetic wounds early after injury remains unknown. In this study,we report that in contrast to prolonged exposure to high glucose,which makes monocytes proinflammatory,short-term exposure to high glucose causes a rapid monocyte reprogramming,manifested by increased expression and secretion of IL-10,which in an autocrine/paracrine fashion reduces glucose uptake and transforms monocytes into an anti-inflammatory phenotype by dampening signaling through toll-like receptors. We show that IL-10 expression is significantly increased in diabetic wounds during the acute phase of healing,causing significant reductions in toll-like receptor signaling and proinflammatory cytokine production,delaying macrophage and leukocyte responses,and underlying healing impairment in diabetic wounds. Importantly,blocking IL-10 signaling during the acute phase of healing improves toll-like receptor signaling,increases proinflammatory cytokine production,enhances macrophage and leukocyte responses,and stimulates healing in diabetic wounds. We posit that anti-IL-10 strategies have therapeutic potential if added topically after surgical debridement,which resets chronic wounds into acute fresh wounds. View Publication

BACKGROUND & AIMS An invasive form of intestinal Entamoeba (E.) histolytica infection,which causes amoebic liver abscess,is more common in men than in women. Immunopathological mechanisms are responsible for the more severe outcome in males. Here,we used a mouse model of hepatic amoebiasis to investigate the contribution of hepatic hypoxia-inducible factor (HIF)-1$\alpha$ to T helper 17 (Th17)/regulatory T cell (Treg) responses in the context of the sex-specific outcome of liver damage. METHODS C57BL/6J mice were infected intrahepatically with E. histolytica trophozoites. HIF-1$\alpha$ expression was determined by qPCR,flow cytometry and immunohistochemistry. Tregs and Th17 cells were analysed by immunohistochemistry and flow cytometry. Finally,male and female hepatocyte-specific Hif1$\alpha$ knockout mice were generated,and the effect of HIF-1$\alpha$ on abscess development,the cytokine milieu,and Th17/Treg differentiation was examined. RESULTS E. histolytica infection increased hepatic HIF-1$\alpha$ levels,along with the elevated frequencies of hepatic Th17 and Treg cells. While the Th17 cell population was larger in male mice,Tregs characterised by increased expression of Foxp3 in female mice. Male mice displayed increased IL-6 expression,contributing to immunopathology; this increase in IL-6 expression declined upon deletion of hepatic HIF-1$\alpha$. In both sexes,hepatic deletion of HIF-1$\alpha$ reduced the Th17 cell frequency; however,the percentage of Tregs was reduced in female mice only. CONCLUSIONS Hepatic HIF-1$\alpha$ modulates the sex-specific outcome of murine E. histolytica infection. Our results suggest that in male mice,Th17 cells can be modulated by hepatic HIF-1$\alpha$ via IL-6,indicating marked involvement in the immunopathology underlying abscess development. Strong expression of Foxp3 by hepatic Tregs from female mice suggests a potent immunosuppressive function,leading to initiation of liver regeneration. LAY SUMMARY Infection with the parasite Entamoeba histolytica activates immunopathological mechanisms in male mice,which lead to liver abscesses that are larger than those in female mice. In the absence of the protein HIF-1$\alpha$ in hepatocytes,abscess formation is reduced; moreover,the sex difference in abscess size is abolished. These results suggest that HIF-1$\alpha$ modulates the immune response involved in the induction of immunopathology,resulting in differential disease susceptibility in males and females. View Publication

BACKGROUND During the COVID-19 pandemic,thousands of pregnant women have been infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The implications of maternal SARS-CoV-2 infection on fetal and childhood well-being need to be characterized. We aimed to characterize the fetal immune response to maternal SARS-CoV-2 infection. METHODS We performed single-cell RNA-sequencing and T cell receptor sequencing on cord blood mononuclear cells (CBMCs) from newborns of mothers infected with SARS-CoV-2 in the third trimester (cases) or without SARS-CoV-2 infection (controls). RESULTS We identified widespread gene expression changes in CBMCs from cases,including upregulation of interferon-stimulated genes and major histocompatibility complex genes in CD14+ monocytes,transcriptional changes suggestive of activation of plasmacytoid dendritic cells,and activation and exhaustion of natural killer cells. Lastly,we observed fetal T cell clonal expansion in cases compared to controls. CONCLUSIONS As none of the infants were infected with SARS-CoV-2,our results suggest that maternal SARS-CoV-2 infection might modulate the fetal immune system in the absence of vertical transmission. IMPACT The implications of maternal SARS-CoV-2 infection in the absence of vertical transmission on fetal and childhood well-being are poorly understood. Maternal SARS-CoV-2 infection might modulate the fetal immune system in the absence of vertical transmission. This study raises important questions about the untoward effects of maternal SARS-CoV-2 on the fetus,even in the absence of vertical transmission. View Publication

Peptidylarginine deiminase 4 (PAD4) is a key regulator of inflammation but its function in infections remains incompletely understood. We investigate PAD4 in the context of malaria and demonstrate a role in regulation of immune cell trafficking and chemokine production. PAD4 regulates liver immunopathology by promoting neutrophil trafficking in a Plasmodium chabaudi mouse malaria model. In human macrophages,PAD4 regulates expression of CXCL chemokines in response to stimulation with TLR ligands and P. falciparum. Using patient samples,we show that CXCL1 may be a biomarker for severe malaria. PAD4 inhibition promotes disease tolerance and may represent a therapeutic avenue in malaria. View Publication

Successful implantation requires the coordinated migration and invasion of trophoblast cells from out of the blastocyst and into the endometrium. This process relies on signals produced by cells in the maternal endometrium. However,the relative contribution of stroma cells remains unclear. The study of human implantation has major technical limitations,therefore the need of in vitro models to elucidate the molecular mechanisms. Using a recently described 3D in vitro models we evaluated the interaction between trophoblasts and human endometrial stroma cells (hESC),we assessed the process of trophoblast migration and invasion in the presence of stroma derived factors. We demonstrate that hESC promotes trophoblast invasion through the generation of an inflammatory environment modulated by TNF-?. We also show the role of stromal derived IL-17 as a promoter of trophoblast migration through the induction of essential genes that confer invasive capacity to cells of the trophectoderm. In conclusion,we describe the characterization of a cellular inflammatory network that may be important for blastocyst implantation. Our findings provide a new insight into the complexity of the implantation process and reveal the importance of inflammation for embryo implantation. View Publication