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The Mesenchymal-to-Epithelial Transition (MET) has been recognized as a crucial step for successful reprogramming of fibroblasts to induced pluripotent stem cells (iPSCs). Thus,it has been demonstrated,that the efficiency of reprogramming can be enhanced by promoting an epithelial expression program in cells,with a concomitant repression of key mesenchymal genes. However,a detailed characterization of the epithelial transition associated with the acquisition of a pluripotent phenotype is still lacking to this date. Here,we integrate a panel of morphological approaches with gene expression analyses to visualize the dynamics of episomal reprogramming of human fibroblasts to iPSCs. We provide the first ultrastructural analysis of human fibroblasts at various stages of episomal iPSC reprogramming,as well as the first real-time live cell visualization of a MET occurring during reprogramming. The results indicate that the MET manifests itself approximately 6-12. days after electroporation,in synchrony with the upregulation of early pluripotency markers,and resembles a reversal of the Epithelial-to-Mesenchymal Transition (EMT) which takes place during mammalian gastrulation. View Publication

The lipophilic statin lovastatin decreases cholesterol synthesis and is a safe and effective treatment for the prevention of cardiovascular diseases. Growing evidence points at antitumor potential of lovastatin. Therefore,understanding the molecular mechanism of lovastatin function in different cell types is critical to effective therapy design. In this study,we investigated the effects of lovastatin on the differentiation potential of human embryonic stem (hES) cells (H9 cell line). Multiparameter flow cytometric assay was used to detect changes in the expression of transcription factors characteristic of hES cells. We found that lovastatin treatment delayed NANOG downregulation during ectodermal and endodermal differentiation. Likewise,expression of ectodermal (SOX1 and OTX2) and endodermal (GATA4 and FOXA2) markers was higher in treated cells. Exposure of hES cells to lovastatin led to a minor decrease in the expression of SSEA-3 and a significant reduction in CD133 expression. Treated cells also formed fewer embryoid bodies than control cells. By analyzing hES with and without CD133,we discovered that CD133 expression is required for proper formation of embryoid bodies. In conclusion,lovastatin reduced the heterogeneity of hES cells and impaired their differentiation potential. View Publication

Background: B cells play an important role in the development and maintenance of rheumatoid arthritis (RA). Although IL-10-producing B cells represent a major subset of regulatory B cells (Bregs) able to suppress autoimmune and inflammatory responses,recent reports showed that B cell-mediated immune suppression may also occur independent of IL-10. For instance,B cells can modulate T cell immune responses through the expression of regulatory molecules such as PD-L1. So far,PD-L1-expressing B cells have not been analyzed in RA patients. Objective: To analyze the frequency of PD-L1-expressing B cells in the peripheral blood of RA patients compared to healthy controls (HC) matched for sex and age,their function on T cell response and their changes in response to therapy. Methods: Fresh peripheral blood B cells from RA patients and HC were characterized by flow cytometry and their functionality assessed in a co-culture system with autologous T cells. Results: The frequencies of CD19+PD-L1+ B cells,CD24hiCD38-PD-L1+ and CD24hiCD38hiPD-L1+ B cells were significantly lower in untreated RA patients than in HC. In a follow-up study,the frequencies of PD-L1+ B cells (CD19+PD-L1+ B cells,CD24hiCD38-PD-L1+ and CD24hiCD38hiPD-L1+ B cells) increased significantly after treatment in good responder patients,although the frequency of total CD24hiCD38hi B cells decreased. CD19+ B cells from untreated RA patients and HC upregulated PD-L1 expression similarly upon stimulation with CpG plus IL-2 and were able to suppress,in vitro,CD8+ T cell proliferation and cytokine production in a PD-L1-dependent manner. Conclusions: Our results show that PD-L1+ B cells exhibiting T cell suppressive capacity are significantly decreased in untreated RA patients but increase in response to successful treatment. PD-L1 expression on B cells from RA patients can be modulated in vitro and PD-L1+ B cells could thus provide new perspectives for future treatment strategies. View Publication

Allogeneic hematopoietic cell transplant (allo-HCT) can be curative for certain hematologic malignancies,but the risk of graft-versus-host disease (GVHD) is a major limitation for wider application. Ideally,strategies to improve allo-HCT would involve suppression of T lymphocytes that drive GVHD while sparing those that mediate graft-versus-malignancy (GVM). Recently,using a xenograft model,we serendipitously discovered that myxoma virus (MYXV) prevented GVHD while permitting GVM. In this study,we show that MYXV binds to resting,primary human T lymphocytes but will only proceed into active virus infection after the T cells receive activation signals. MYXV-infected T lymphocytes exhibited impaired proliferation after activation with reduced expression of interferon-?,interleukin-2 (IL-2),and soluble IL-2R?,but did not affect expression of IL-4 and IL-10. MYXV suppressed T-cell proliferation in 2 patterns (full vs partial) depending on the donor. In terms of GVM,we show that MYXV-infected activated human T lymphocytes effectively deliver live oncolytic virus to human multiple myeloma cells,thus augmenting GVM by transfer of active oncolytic virus to residual cancer cells. Given this dual capacity of reducing GVHD plus increasing the antineoplastic effectiveness of GVM,ex vivo virotherapy with MYXV may be a promising clinical adjunct to allo-HCT regimens. View Publication

BackgroundThe simultaneous differentiation of human pluripotent stem cells (hPSCs) into both endodermal and mesodermal lineages is crucial for developing complex,vascularized tissues,yet poses significant challenges. This study explores a method for co-differentiation of mesoderm and endoderm,and their subsequent differentiation into pancreatic progenitors (PP) with endothelial cells (EC).MethodsTwo hPSC lines were utilized. By manipulating WNT signaling,we optimized co-differentiation protocols of mesoderm and endoderm through adjusting the concentrations of CHIR99021 and mTeSR1. Subsequently,mesoderm and endoderm were differentiated into vascularized pancreatic progenitors (vPP) by adding VEGFA. The differentiation characteristics and potential of vPPs were analyzed via transcriptome sequencing and functional assays.ResultsA low-dose CHIR99021 in combination with mTeSR1 yielded approximately 30% mesodermal and 70% endodermal cells. Introduction of VEGFA significantly enhanced EC differentiation without compromising PP formation,increasing the EC proportion to 13.9%. Transcriptomic analyses confirmed the effectiveness of our protocol,showing up-regulation of mesodermal and endothelial markers,alongside enhanced metabolic pathways. Functional assays demonstrated that vPPs could efficiently differentiate into insulin-producing ?-cells,as evidenced by increased expression of ?-cell markers and insulin secretion.ConclusionOur findings provide a robust method for generating vPPs,which holds significant promise for regenerative medicine applications,particularly in diabetes treatment.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13287-024-04120-5. View Publication

Tuberous Sclerosis Complex (TSC) is a debilitating developmental disorder characterized by a variety of clinical manifestations. While benign tumors in the heart,lungs,kidney,and brain are all hallmarks of the disease,the most severe symptoms of TSC are often neurological,including seizures,autism,psychiatric disorders,and intellectual disabilities. TSC is caused by loss of function mutations in the TSC1 or TSC2 genes and consequent dysregulation of signaling via mechanistic Target of Rapamycin Complex 1 (mTORC1). While TSC neurological phenotypes are well-documented,it is not yet known how early in neural development TSC1/2-mutant cells diverge from the typical developmental trajectory. Another outstanding question is the contribution of homozygous-mutant cells to disease phenotypes and whether such phenotypes are also seen in the heterozygous-mutant populations that comprise the vast majority of cells in patients. Using TSC patient-derived isogenic induced pluripotent stem cells (iPSCs) with defined genetic changes,we observed aberrant early neurodevelopment in vitro,including misexpression of key proteins associated with lineage commitment and premature electrical activity. These alterations in differentiation were coincident with hundreds of differentially methylated DNA regions,including loci associated with key genes in neurodevelopment. Collectively,these data suggest that mutation or loss of TSC2 affects gene regulation and expression at earlier timepoints than previously appreciated,with implications for whether and how prenatal treatment should be pursued. View Publication

IntroductionInnate lymphoid cells (ILCs) are enriched at mucosal surfaces where they respond rapidly to environmental stimuli and contribute to both tissue inflammation and healing. MethodsTo gain insight into the role of ILCs in the pathology and recovery from COVID-19 infection,we employed a multi-omics approach consisting of Abseq and targeted mRNA sequencing to respectively probe the surface marker expression,transcriptional profile and heterogeneity of ILCs in peripheral blood of patients with COVID-19 compared with healthy controls. ResultsWe found that the frequency of ILC1 and ILC2 cells was significantly increased in COVID-19 patients. Moreover,all ILC subsets displayed a significantly higher frequency of CD69-expressing cells,indicating a heightened state of activation. ILC2s from COVID-19 patients had the highest number of significantly differentially expressed (DE) genes. The most notable genes DE in COVID-19 vs healthy participants included a) genes associated with responses to virus infections and b) genes that support ILC self-proliferation,activation and homeostasis. In addition,differential gene regulatory network analysis revealed ILC-specific regulons and their interactions driving the differential gene expression in each ILC. DiscussionOverall,this study provides mechanistic insights into the characteristics of ILC subsets activated during COVID-19 infection. View Publication

AbstractT cells in the human female genital tract (FGT) are key mediators of susceptibility to and protection from infection,including HIV and other sexually transmitted infections. There is a critical need for increased understanding of the distribution and activation of T cell populations in the FGT,but current sampling methods require a healthcare provider and are expensive,limiting the ability to study these populations longitudinally. To address these challenges,we have developed a method to sample immune cells from the FGT utilizing disposable menstrual discs which are noninvasive,self-applied,and low in cost. To demonstrate reproducibility,we sampled the cervicovaginal fluid of healthy,reproductive-aged individuals using menstrual discs across 3 sequential days. Cervicovaginal fluid was processed for cervicovaginal cells,and high-parameter flow cytometry was used to characterize immune populations. We identified large numbers of live,CD45+ leukocytes,as well as distinct populations of T cells and B cells. Within the T cell compartment,activation and suppression status of T cell subsets were consistent with previous studies of the FGT utilizing current approaches,including identification of both tissue-resident and migratory populations. In addition,the T cell population structure was highly conserved across days within individuals but divergent across individuals. Our approach to sample immune cells in the FGT with menstrual discs will decrease barriers to participation and empower longitudinal sampling in future research studies. View Publication

BackgroundT cells are contributors to atherosclerosis pathogenesis. Granulocyte-macrophage-colony-stimulating factor (GM-CSF)-producing T helper (ThGM) cells,a specialized helper T cell subset that highly expresses GM-CSF but lacks other helper T cell markers,could exacerbate atherosclerosis development. Calycosin has been reported to suppress atherosclerosis progression. However,the effect of calycosin on ThGM cells is unknown. This study was designed to test the calycosin-induced impact on the pro-atherosclerotic function of ThGM cells in a mouse atherosclerosis model.MethodsApolipoprotein E knockout (ApoE−/−) mice were fed a high-fat diet and calycosin. The phenotype and cytokine expression of aortic ThGM cells were assessed by flow cytometry. Calycosin-derived influences on ThGM cell differentiation,proliferation,and function were determined by flow cytometry,quantitative RT-PCR,Immunoblotting,gene silencing assays,and co-culture with macrophages.ResultsAortic ThGM cell frequency was attenuated after calycosin administration. Live aortic ThGM cells,phenotypically featuring CD4+CCR6−CCR8−CXCR3−CCR10+,showed slower proliferation and weaker macrophage-activating capability in calycosin-treated mice. Besides,calycosin repressed in vitro ThGM cell differentiation and subsequently impaired ThGM cell-mediated macrophage activation,oxidized low-density lipoprotein (Ox-LDL) uptake,and foam cell formation. Importantly,calycosin upregulated nuclear receptor subfamily 4 group A member 3 (NR4A3) in ThGM cells. NR4A3 silencing partially restored the function of calycosin-treated ThGM cells.ConclusionCalycosin inhibits ThGM cell activity to suppress ThGM-cell-mediated activation of pro-atherosclerotic macrophages to ultimately ameliorate atherosclerosis progression. Therefore,we revealed a novel mechanism by which calycosin protects against atherosclerosis. View Publication

Overcoming drug resistance and targeting cancer stem cells remain challenges for curative cancer treatment. To investigate the role of miRNAs in regulating drug resistance and leukemic stem cell (LSCs) fate,we performed global transcriptome profiling in treatment-na{\{i}}ve chronic myeloid leukemia (CML) stem/progenitor cells and identified that miR-185 levels anticipate their response to ABL tyrosine kinase inhibitors (TKIs). miR-185 functions as a tumor suppressor; its restored expression impaired survival of drug-resistant cells sensitized them to TKIs in vitro and markedly eliminated long-term repopulating LSCs and infiltrating blast cells conferring a survival advantage in pre-clinical xenotransplantation models. Integrative analysis with mRNA profiles uncovered PAK6 as a crucial target of miR-185 and pharmacological inhibition of PAK6 perturbed the RAS/MAPK pathway and mitochondrial activity sensitizing therapy-resistant cells to TKIs. Thus miR-185 presents as a potential predictive biomarker and dual targeting of miR-185-mediated PAK6 activity and BCR-ABL may provide a valuable strategy for overcoming drug resistance in patients." View Publication

Regulation of the homeostasis of vascular endothelium is critical for the processes of vascular remodeling and angiogenesis under physiological and pathological conditions. Here we show that doxorubicin (Dox),a drug used in antitumor therapy,triggered a marked accumulation of p53 and induced CD95 gene expression and apoptosis in proliferating human umbilical vein endothelial cells (HUVECs). Transfection and site-directed mutagenesis experiments using the CD95 promoter fused to an intronic enhancer indicated the requirement for a p53 site for Dox-induced promoter activation. Furthermore,the p53 inhibitor pifithrin-alpha (PFT-alpha) blocked both promoter inducibility and protein up-regulation of CD95 in response to Dox. Up-regulated CD95 in Dox-treated cells was functional in eliciting apoptosis upon incubation of the cells with an agonistic CD95 antibody. However,Dox-mediated apoptosis was independent of CD95/CD95L interaction. The analysis of apoptosis in the presence of PFT-alpha and benzyloxycarbonyl-Val-Ala-dl-Asp-fluoromethylketone revealed that both p53 and caspase activation are required for Dox-mediated apoptosis of HUVECs. Finally,Dox triggered Bcl-2 down-regulation,cytochrome c release from mitochondria,and the activation of caspases 9 and 3,suggesting the involvement of a mitochondrially operated pathway of apoptosis. These results highlight the role of p53 in the response of primary endothelial cells to genotoxic drugs and may reveal a novel mechanism underlying the antitumoral properties of Dox,related to its ability to induce apoptosis in proliferating endothelial cells. View Publication

Management of chronic kidney disease (CKD) remains a major challenge due limited therapeutic options to reverse fibrosis,which is a critical feature in CKD. Partial epithelial-to-mesenchymal transition (EMT) of tubular epithelial cells (TECs) is a key driver of fibrosis,and has become an important focus for kidney protection strategies. Blood platelets,a major source of circulating transforming growth factor beta (TGF-β),are implicated in pathogenesis of CKD,but their involvement in EMT and kidney fibrosis remains uncertain. Methods: We used two mouse models of renal fibrosis—diabetic kidney disease (DKD) and unilateral ureter obstruction (UUO)—to examine the connection between platelets,partial EMT,and fibrosis. Platelet inhibition or depletion was performed to assess EMT,cell cycle arrest,and fibrosis. In vitro,platelets were applied to TECs and kidney organoids. To determine the role of TGF-β signaling,we used TGF-βRI inhibitor. Expression of EMT,and fibrosis markers,as well as TGF-β1 signaling,were analyzed using western blot,reverse transcription quantitative PCR (RT-qPCR),enzyme-linked immunosorbent assay (ELISA),and immunostaining. Results: In both animal models,platelet inhibition or depletion resulted in reduced expression of cell cycle arrest marker p21,partial EMT and fibrosis. In vitro,activated platelets stimulated cell cycle arrest,EMT,and fibrosis in TECs and kidney organoids. Chronically injured TECs experience cell-cycle arrest which promote a paracrine EMT program in TECs,jointly leading to fibrosis. This platelet-mediated effect on cell cycle arrest and EMT was driven by TGF-β1 signaling,as selective inhibition of the TGF-β receptor rescued these dysfunctional phenotypes. Conclusions: Our study demonstrates that platelets activate the TGF-β1 pathway,leading to cell cycle arrest,EMT and renal fibrosis. These findings suggest that antiplatelet therapies may have potential renoprotective effects by protecting tubular homeostasis,attenuating partial EMT and fibrosis. View Publication