技术资料

During viral infections viruses express molecules that interfere with the host-cell death machinery and thus inhibit cell death responses. For example the viral FLIP (vFLIP) encoded by Kaposi's sarcoma-associated herpesvirus interacts and inhibits the central cell death effector,Caspase-8. In order to analyze the impact of anti-apoptotic viral proteins,like vFlip,on liver physiology in vivo,mice expressing vFlip constitutively in hepatocytes (vFlipAlbCre+) were generated. Transgenic expression of vFlip caused severe liver tissue injury accompanied by massive hepatocellular necrosis and inflammation that finally culminated in early postnatal death of mice. On a molecular level,hepatocellular death was mediated by RIPK1-MLKL necroptosis driven by an autocrine TNF production. The loss of hepatocytes was accompanied by impaired bile acid production and disruption of the bile duct structure with impact on the liver-gut axis. Notably,embryonic development and tissue homeostasis were unaffected by vFlip expression. In summary our data uncovered that transgenic expression of vFlip can cause severe liver injury in mice,culminating in multiple organ insufficiency and death. These results demonstrate that viral cell death regulatory molecules exhibit different facets of activities beyond the inhibition of cell death that may merit more sophisticated in vitro and in vivo analysis. View Publication

Drug-induced gastrointestinal toxicity (GIT) is a common treatment-emergent adverse event that can negatively impact dosing,thereby limiting efficacy and treatment options for patients. An in vitro assay of GIT is needed to address patient variability,mimic the microphysiology of the gut,and accurately predict drug-induced GIT. Primary human ileal organoids (termed 'enteroids') have proven useful for stimulating intestinal stem cell proliferation and differentiation to multiple cell types present in the gut epithelium. Enteroids have enabled characterization of gut biology and the signaling involved in the pathogenesis of disease. Here,enteroids were differentiated from four healthy human donors and assessed for culture duration-dependent differentiation status by immunostaining for gut epithelial markers lysozyme,chromogranin A,mucin,and sucrase isomaltase. Differentiated enteroids were evaluated with a reference set of 31 drugs exhibiting varying degrees of clinical incidence of diarrhea,a common manifestation of GIT that can be caused by drug-induced thinning of the gut epithelium. An assay examining enteroid viability in response to drug treatment demonstrated 90{\%} accuracy for recapitulating the incidence of drug-induced diarrhea. The human enteroid viability assay developed here presents a promising in vitro model for evaluating drug-induced diarrhea. View Publication

Exposure to thalidomide during a critical window of development results in limb defects in humans and non-human primates while mice and rats are refractory to these effects. Thalidomide-induced teratogenicity is dependent on its binding to cereblon (CRBN),the substrate receptor of the Cul4A-DDB1-CRBN-RBX1 E3 ubiquitin ligase complex. Thalidomide binding to CRBN elicits subsequent ubiquitination and proteasomal degradation of CRBN neosubstrates including SALL4,a transcription factor of which polymorphisms phenocopy thalidomide-induced limb defects in humans. Herein,thalidomide-induced degradation of SALL4 was examined in human induced pluripotent stem cells (hiPSCs) that were differentiated either to lateral plate mesoderm (LPM)-like cells,the developmental ontology of the limb bud,or definitive endoderm. Thalidomide and its immunomodulatory drug (IMiD) analogs,lenalidomide,and pomalidomide,dose-dependently inhibited hiPSC mesendoderm differentiation. Thalidomide- and IMiD-induced SALL4 degradation can be abrogated by CRBN V388I mutation or SALL4 G416A mutation in hiPSCs. Genetically modified hiPSCs expressing CRBN E377V/V388I mutant or SALL4 G416A mutant were insensitive to the inhibitory effects of thalidomide,lenalidomide,and pomalidomide on LPM differentiation while retaining sensitivity to another known limb teratogen,all-trans retinoic acid (atRA). Finally,disruption of LPM differentiation by atRA or thalidomide perturbed subsequent chondrogenic differentiation in vitro. The data here show that thalidomide,lenalidomide,and pomalidomide affect stem cell mesendoderm differentiation through CRBN-mediated degradation of SALL4 and highlight the utility of the LPM differentiation model for studying the teratogenicity of new CRBN modulating agents. View Publication

BACKGROUND Lymphotoxin $\beta$ receptor (LT$\beta$R) plays important roles in the development of the immune system and immune response. At the cellular level,ligand-bound LT$\beta$R activates the pro-inflammatory NF-$\kappa$B pathway but the detailed mechanisms regulating its signaling remain unknown. Understanding them is of high importance since LT$\beta$R and its ligands are promising therapeutic targets. Here,we studied the consequences of perturbed cellular cholesterol content on LT$\beta$R-induced NF-$\kappa$B signaling. METHODS To modulate cholesterol availability and/or level in lung carcinoma A549 and H2228,and endothelial HUVEC cells different treatment regimens with filipin,methyl-$\beta$-cyclodextrin and simvastatin were applied. LT$\beta$R localization was studied by confocal microscopy. The activity of LT$\beta$R-induced NF-$\kappa$B pathway was assessed by measuring the levels of NF-$\kappa$B pathway inhibitor I$\kappa$B$\alpha$ and phosphorylation of RelA transcription factor by Western blotting. The NF-$\kappa$B transcriptional response,production of chemokines and adhesion molecules were examined by qRT-PCR,ELISA,and Western blotting,respectively. Adherence of different types of primary immune cells to epithelial A549 cells and endothelial HUVECs was measured fluorometrically. Interactions of LT$\beta$R with its protein partners were investigated by immunoprecipitation. RESULTS We showed that filipin-mediated sequestration of cholesterol or its depletion from the plasma membrane with methyl-$\beta$-cyclodextrin impaired LT$\beta$R internalization and potentiated LT$\beta$R-dependent activation of the canonical branch of the NF-$\kappa$B pathway. The latter was manifested by enhanced degradation of I$\kappa$B$\alpha$ inhibitor,elevated RelA phosphorylation,substantial increase in the expression of NF-$\kappa$B target genes encoding,among others,cytokines and adhesion molecules known to play important roles in immune response. It was followed by robust secretion of CXCL8 and upregulation of ICAM1,that favored the adhesion of immune cells (NK and T cells,neutrophils) to A549 cells and HUVECs. Mechanistically,we showed that cholesterol depletion stabilized interactions of ligand-stimulated LT$\beta$R with modified forms of TRAF2 and NEMO proteins. CONCLUSIONS Our results showed that the reduction of the plasma membrane content of cholesterol or its sequestration strongly potentiated signaling outcome initiated by LT$\beta$R. Thus,drugs modulating cholesterol levels could potentially improve efficacy of LT$\beta$R-based therapies. Video abstract. View Publication

PURPOSE The outgrowth of antigen-negative variants is a significant challenge for adoptive therapy with T cells that target a single specificity. Chimeric antigen receptors (CAR) are typically designed with one or two scFvs that impart antigen specificity fused to activation and costimulation domains of T-cell signaling molecules. We designed and evaluated the function of CARs with up to three specificities for overcoming tumor escape using Designed Ankyrin Repeat Proteins (DARPins) rather than scFvs for tumor recognition. EXPERIMENTAL DESIGN A monospecific CAR was designed with a DARPin binder (E01) specific for EGFR and compared with a CAR designed using an anti-EGFR scFv. CAR constructs in which DARPins specific for EGFR,EpCAM,and HER2 were linked together in a single CAR were then designed and optimized to achieve multispecific tumor recognition. The efficacy of CAR-T cells bearing a multispecific DARPin CAR for treating tumors with heterogeneous antigen expression was evaluated in vivo. RESULTS The monospecific anti-EGFR E01 DARPin conferred potent tumor regression against EGFR+ targets that was comparable with an anti-EGFR scFv CAR. Linking three separate DARPins in tandem was feasible and in an optimized format generated a single tumor recognition domain that targeted a mixture of heterogeneous tumor cells,each expressing a single antigen,and displayed synergistic activity when tumor cells expressed more than one target antigen. CONCLUSIONS DARPins can serve as high-affinity recognition motifs for CAR design,and their robust architecture enables linking of multiple binders against different antigens to achieve functional synergy and reduce antigen escape. View Publication

The recent advances,offered by cell therapy in the regenerative medicine field,offer a revolutionary potential for the development of innovative cures to restore compromised physiological functions or organs. Adult myogenic precursors,such as myoblasts or satellite cells,possess a marked regenerative capacity,but the exploitation of this potential still encounters significant challenges in clinical application,due to low rate of proliferation in vitro,as well as a reduced self-renewal capacity. In this scenario,induced pluripotent stem cells (iPSCs) can offer not only an inexhaustible source of cells for regenerative therapeutic approaches,but also a valuable alternative for in vitro modeling of patient-specific diseases. In this study we established a reliable protocol to induce the myogenic differentiation of iPSCs,generated from pericytes and fibroblasts,exploiting skeletal muscle-derived extracellular vesicles (EVs),in combination with chemically defined factors. This genetic integration-free approach generates functional skeletal myotubes maintaining the engraftment ability in vivo. Our results demonstrate evidence that EVs can act as biological shuttles" to deliver specific bioactive molecules for a successful transgene-free differentiation offering new opportunities for disease modeling and regenerative approaches." View Publication

Prenatal cannabis exposure (PCE) influences human brain development,but it is challenging to model PCE using animals and current cell culture techniques. Here,we developed a one-stop microfluidic platform to assemble and culture human cerebral organoids from human embryonic stem cells (hESC) to investigate the effect of PCE on early human brain development. By incorporating perfusable culture chambers,air-liquid interface,and one-stop protocol,this microfluidic platform can simplify the fabrication procedure and produce a large number of organoids (169 organoids per 3.5 cm × 3.5 cm device area) without fusion,as compared with conventional fabrication methods. These one-stop microfluidic assembled cerebral organoids not only recapitulate early human brain structure,biology,and electrophysiology but also have minimal size variation and hypoxia. Under on-chip exposure to the psychoactive cannabinoid,$\Delta$-9-tetrahydrocannabinol (THC),cerebral organoids exhibited reduced neuronal maturation,downregulation of cannabinoid receptor type 1 (CB1) receptors,and impaired neurite outgrowth. Moreover,transient on-chip THC treatment also decreased spontaneous firing in these organoids. This one-stop microfluidic technique enables a simple,scalable,and repeatable organoid culture method that can be used not only for human brain organoids but also for many other human organoids including liver,kidney,retina,and tumor organoids. This technology could be widely used in modeling brain and other organ development,developmental disorders,developmental pharmacology and toxicology,and drug screening. View Publication

Tandemers 2MG,2MG3,3MG and 4MG are derivatives of the potent anti-HIV-1 microbicide candidate griffithsin (GRFT). We compared these compounds anti-HIV-1 activity to GRFT using the viruses CAP206.08 and CAAN5342.A2 that have decreased sensitivity to this lectin. The 2MG and 2MG3 tandemers had similar activity to GRFT against cell-free and cell-associated viruses,while 3MG and 4MG were significantly more potent. Furthermore,the restoration of the 234N or 295N glycan in these viruses,known to increase sensitivity to GRFT,also increased sensitivity to 2MG and 2MG3,and not to 3MG and 4MG. In addition,GRFT resistant viruses generated in-vitro were equally resistant to 2MG and 2MG3 while they had considerably low resistance to 3MG and 4MG. Lastly,all five compounds showed increased inhibitory activity in seminal and vaginal simulants although the effect was more pronounced in the former. These data support further studies of tandemers as potential microbicides. View Publication

To date,the effects of endurance exercise training on lymphocyte physiology at the kinome level are largely unknown. Therefore,the present study used a highly sensitive peptide-based kinase activity profiling approach to investigate if the basal activity of tyrosine (Tyr) and serine/threonine (Ser/Thr) kinases of human lymphocytes is affected by the aerobic endurance training status. Results revealed that the activity of various tyrosine kinases of the FGFR family and ZAP70 was increased,whereas the activity of multiple Ser/Thr kinases such as IKK$\alpha$,CaMK4,PKA$\alpha$,PKC$\alpha$+$\delta$ (among others) was decreased in lymphocytes of endurance trained athletes (ET). Moreover,functional associations between several differentially regulated kinases in ET-derived lymphocytes were demonstrated by phylogenetic mapping and network analysis. Especially,Ser/Thr kinases of the AGC-kinase (protein kinase A,G,and C) family represent exercise-sensitive key components within the lymphocytes kinase network that may mediate the long-term effects of endurance training. Furthermore,KEGG (Kyoto Encyclopedia of Genes and Genomes) and Reactome pathway analysis indicate that Ras as well as intracellular signaling by second messengers were found to be enriched in the ET individuals. Overall,our data suggest that endurance exercise training improves the adaptive immune competence by modulating the activity of multiple protein kinases in human lymphocytes. View Publication

Bovine viral diarrhea virus (BVDV) is an important viral disease of cattle that causes immune dysfunction. Macrophages are the key cells for the initiation of the innate immunity and play an important role in viral pathogenesis. In this in vitro study,we studied the effect of the supernatant of BVDV-infected macrophage on immune dysfunction. We infected bovine monocyte-derived macrophages (MDM) with high or low virulence strains of BVDV. The supernatant recovered from BVDV-infected MDM was used to examine the functional activity and surface marker expression of normal macrophages as well as lymphocyte apoptosis. Supernatants from the highly virulent 1373-infected MDM reduced phagocytosis,bactericidal activity and downregulated MHC II and CD14 expression of macrophages. Supernatants from 1373-infected MDM induced apoptosis in MDBK cells,lymphocytes or BL-3 cells. By protein electrophoresis,several protein bands were unique for high-virulence,1373-infected MDM supernatant. There was no significant difference in the apoptosis-related cytokine mRNA (IL-1beta,IL-6 and TNF-a) of infected MDM. These data suggest that BVDV has an indirect negative effect on macrophage functions that is strain-specific. Further studies are required to determine the identity and mechanism of action of these virulence factors present in the supernatant of the infected macrophages. View Publication