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BACKGROUND Glioblastoma (GBM) is the most common and aggressive form of primary brain tumor. Although numerous postoperative therapeutic strategies have already been developed,including radiotherapy,tumors inevitably recur after several years of treatment. The coinhibitory molecule B7-H4 negatively regulates T cell immune responses and promotes immune escape. Exosomes mediate intercellular communication and initiate immune evasion in the tumor microenvironment (TME). OBJECTIVE This study aimed to determine whether B7-H4 is upregulated by radiation and loaded into exosomes,thus contributing to immunosuppression and enhancing tumor growth. METHODS Iodixanol density-gradient centrifugation and flow cytometry were used to verify exosomal B7-H4. Na{\{i}}ve T cells were differentiated into Th1 cells with or without exosomes. T cell-secreted cytokines and markers of T cell subsets were measured. Mechanistically the roles of B7-H4 and ALIX in GBM were analyzed using databases and tissue samples. Co-immunoprecipitation and pull-down assays were used to tested the direct interactions between ATM and ALIX or STAT3. In vitro ATM kinase assays western blotting and site-directed mutation were used to assess ATM-mediated STAT3 phosphorylation. Finally the contribution of exosomal B7-H4 to immunosuppression and tumor growth was investigated in vivo. RESULTS Exosomes from irradiated GBM cells decreased the anti-tumor immune response of T cell in vitro and in vivo via delivered B7-H4. Mechanistically irradiation promoted exosome biogenesis by increasing the ATM-ALIX interaction. Furthermore the ATM-phosphorylated STAT3 was found to directly binds to the B7-H4 promoter to increase its expression. Finally the radiation-induced increase in exosomal B7-H4 induced FoxP3 expression during Th1 cell differentiation via the activated STAT1 pathway. In vivo exosomal B7-H4 decreased the radiation sensitivity of GBM cells and reduced the survival of GBM mice model. CONCLUSION This study showed that radiation-enhanced exosomal B7-H4 promoted immunosuppression and tumor growth hence defining a direct link between irradiation and anti-tumor immune responses. Our results suggest that co-administration of radiotherapy with anti-B7-H4 therapy could improve local tumor control and identify exosomal B7-H4 as a potential tumor biomarker." View Publication

Foxp3+ Regulatory T cells (Tregs) are pivotal for the maintenance of tolerance. Alterations in their number and/or function have been proposed to occur in the autoimmune-prone non-obese diabetic (NOD) mouse. Comparing the frequencies and absolute numbers of CD4+Foxp3+CD25+ Tregs among 4 to 6-week old NOD,B6,and BALB/c mice,we observed differences in counts and Foxp3 expression in Tregs from secondary lymphoid organs,but not in the thymus. Upon TCR and IL-2 stimulation,NOD Tregs showed lower responses than Tregs from B6 and BALB/c mice. Indeed,NOD Tregs responded with less proliferation and with smaller increments in the expression of CD25,LAP-1,CD39,PD-1,PD-L1,and LAG-3,when in vitro cultured for 3 days with anti-CD3/CD28 in the absence or presence of IL-2,Tregs from NOD mice showed to be highly dependent on IL-2 to maintain Foxp3 expression. Moreover,NOD Tregs become producers of IL-17 and INF-gamma more easily than Tregs from the other strains. In addition,NOD Tregs showed lower responsiveness to IL-2,with significantly reduced levels of pSTAT5,even at high IL-2 doses,with respect to B6 and BALB/c Tregs. Interestingly,NOD Tregs exhibit differences in the expression of SOCS3,GRAIL,and OTUB1 when compared with Tregs from B6 and BALB/c mice. Both,at steady state conditions and also after activation,Tregs from NOD mice showed increased levels of OTUB1 and low levels of GRAIL. In addition,NOD Tregs had differences in the expression of ubiquitin related molecules that play a role in the maintenance of Foxp3 cellular pools. Indeed,significantly higher STUB1/USP7 ratios were detected in NOD Tregs,both at basal conditions and after stimulation,compared to in B6 and BALB/c Tregs. Moreover,the addition of a proteasome inhibitor to cell cultures,conferred NOD Tregs the ability to retain Foxp3 expression. Herein,we provide evidence indicating a differential expression of SOCS3,GRAIL,and STUB1/USP7 in Tregs from NOD mice,factors known to be involved in IL-2R signaling and to affect Foxp3 stability. These findings add to the current knowledge of the immunobiology of Tregs and may be related to the known insufficiency of Tregs from NOD mice to maintain self-tolerance. View Publication

Increased levels of intestinal bile acids (BAs) are a risk factor for colorectal cancer (CRC). Here,we show that the convergence of dietary factors (high-fat diet) and dysregulated WNT signaling (APC mutation) alters BA profiles to drive malignant transformations in Lgr5-expressing (Lgr5+) cancer stem cells and promote an adenoma-to-adenocarcinoma progression. Mechanistically,we show that BAs that antagonize intestinal farnesoid X receptor (FXR) function,including tauro-$\beta$-muricholic acid (T-$\beta$MCA) and deoxycholic acid (DCA),induce proliferation and DNA damage in Lgr5+ cells. Conversely,selective activation of intestinal FXR can restrict abnormal Lgr5+ cell growth and curtail CRC progression. This unexpected role for FXR in coordinating intestinal self-renewal with BA levels implicates FXR as a potential therapeutic target for CRC. View Publication

The objective of the study was to identify the mechanism of action for a radiation mitigator of the gastrointestinal (GI) acute radiation syndrome (ARS),identified in an unbiased high-throughput screen. We used mice irradiated with a lethal dose of radiation and treated with daily injections of the radiation mitigator 1-[(4-nitrophenyl)sulfonyl]-4-phenylpiperazine to study its effects on key pathways involved in intestinal stem cell (ISC) maintenance. RNASeq,quantitative reverse transcriptase-polymerase chain reaction,and immunohistochemistry were performed to identify pathways engaged after drug treatment. Target validation was performed with competition assays,reporter cells,and in silico docking. 1-[(4-Nitrophenyl)sulfonyl]-4-phenylpiperazine activates Hedgehog signaling by binding to the transmembrane domain of Smoothened,thereby expanding the ISC pool,increasing the number of regenerating crypts and preventing the GI-ARS. We conclude that Smoothened is a target for radiation mitigation in the small intestine that could be explored for use in radiation accidents as well as to mitigate normal tissue toxicity during and after radiotherapy of the abdomen. View Publication

BACKGROUND Vascularization is important for the clinical application of tissue engineered products. Both adipose-derived stem cells (ASCs) and surgical prefabrication can be used to induce angiogenesis in scaffolds. Our aim was to compare the angiogenic potential of ASC-seeded scaffolds combined with scaffold prefabrication with that of non-seeded,non-prefabricated scaffolds. METHODS For prefabrication,functional blood vessels were introduced into the scaffold using a flow-through pedicle system. ASCs were isolated from rat fat deposits. Three-dimensional-printed cylindrical poly-$\epsilon$-caprolactone scaffolds were fabricated by fused deposition modelling. Three groups,each containing six rats,were investigated by using non-seeded,ASC-seeded,and osteogenic induced ASC-seeded scaffolds. In each group,one rat was implanted with two scaffolds in the inguinal region. On the right side,a scaffold was implanted subcutaneously around the inferior epigastric vessels (classic prefabrication group). On the left side,the inferior epigastric vessels were placed inside the prefabricated scaffold in the flow-through pedicle system (flow-through prefabrication group). The vessel density and vascular architecture were examined histopathologically and by $\mu$CT imaging,respectively,at 2 months after implantation. RESULTS The mean vessel densities were 10- and 5-fold higher in the ASC-seeded and osteogenic induced ASC-seeded scaffolds with flow-through prefabrication,respectively,than in the non-seeded classic prefabricated group (p {\textless} 0.001). $\mu$CT imaging revealed functional vessels within the scaffold. CONCLUSION ASC-seeded scaffolds with prefabrication showed significantly improved scaffold vasculogenesis and could be useful for application to tissue engineering products in the clinical settings. View Publication

Juvenile myelomonocytic leukemia (JMML) is a rare aggressive myelodysplastic/myeloproliferative neoplasm of early childhood,initiated by RAS-activating mutations. Genomic analyses have recently described JMML mutational landscape; however,the nature of JMML-propagating cells (JMML-PCs) and the clonal architecture of the disease remained until now elusive. Combining genomic (exome,RNA-seq),Colony forming assay and xenograft studies,we detect the presence of JMML-PCs that faithfully reproduce JMML features including the complex/nonlinear organization of dominant/minor clones,both at diagnosis and relapse. Further integrated analysis also reveals that although the mutations are acquired in hematopoietic stem cells,JMML-PCs are not always restricted to this compartment,highlighting the heterogeneity of the disease during the initiation steps. We show that the hematopoietic stem/progenitor cell phenotype is globally maintained in JMML despite overexpression of CD90/THY-1 in a subset of patients. This study shed new lights into the ontogeny of JMML,and the identity of JMML-PCs,and provides robust models to monitor the disease and test novel therapeutic approaches. View Publication

The aberrant regulation of the epithelial barrier integrity is involved in many diseases of the digestive tract,including inflammatory bowel diseases and colorectal cancer. Intestinal epithelial cell organoid cultures provide new perspectives for analyses of the intestinal barrier in vitro. However,established methods of barrier function analyses from two dimensional cultures have to be adjusted to the analysis of three dimensional organoid structures. Here we describe the methodology for analysis of epithelial barrier function and molecular regulation in intestinal organoids. Barrier responses to interferon-$\gamma$ of intestinal organoids with and without epithelial cell-specific deletion of the interferon-$\gamma$-receptor 2 gene were used as a model system. The established method allowed monitoring of the kinetics of interferon-$\gamma$-induced permeability changes in living organoids. Proteolytic degradation and altered localization of the tight junction proteins claudin-2,-7,and - 15 was detected using confocal spinning disc microscopy with 3D reconstruction. Hessian analysis was used for quantification of re-localization of claudins. In summary,we provide a novel methodologic approach for quantitative analyses of intestinal epithelial barrier functions in the 3D organoid model. View Publication

Ischemia/reperfusion (I/R) injury is mediated in large part by opening of the mitochondrial permeability transition pore (PTP). Consequently,inhibitors of the PTP hold great promise for the treatment of a variety of cardiovascular disorders. At present,PTP inhibition is obtained only through the use of drugs (e.g. cyclosporine A,CsA) targeting cyclophilin D (CyPD) which is a key modulator,but not a structural component of the PTP. This limitation might explain controversial findings in clinical studies. Therefore,we investigated the protective effects against I/R injury of small-molecule inhibitors of the PTP (63 and TR002) that do not target CyPD. Both compounds exhibited a dose-dependent inhibition of PTP opening in isolated mitochondria and were more potent than CsA. Notably,PTP inhibition was observed also in mitochondria devoid of CyPD. Compounds 63 and TR002 prevented PTP opening and mitochondrial depolarization induced by Ca2+ overload and by reactive oxygen species in neonatal rat ventricular myocytes (NRVMs). Remarkably,both compounds prevented cell death,contractile dysfunction and sarcomeric derangement induced by anoxia/reoxygenation injury in NRVMs at sub-micromolar concentrations,and were more potent than CsA. Cardioprotection was observed also in adult mouse ventricular myocytes and human iPSc-derived cardiomyocytes,as well as ex vivo in perfused hearts. Thus,this study demonstrates that 63 and TR002 represent novel cardioprotective agents that inhibit PTP opening independent of CyPD targeting. View Publication

Pre-existent cardiovascular disease is a risk factor for weak anti-viral immunity,but underlying mechanisms remain undefined. Here,we report that patients with coronary artery disease (CAD) have macrophages (M??) that actively suppress the induction of helper T cells reactive to two viral antigens: the SARS-CoV2 Spike protein and the Epstein-Barr virus (EBV) glycoprotein 350. CAD M?? overexpressed the methyltransferase METTL3,promoting the accumulation of N�?-methyladenosine (m6A) in Poliovirus receptor (CD155) mRNA. m6A modifications of positions 1635 and 3103 in the 3'UTR of CD155 mRNA stabilized the transcript and enhanced CD155 surface expression. As a result,the patients' M?? abundantly expressed the immunoinhibitory ligand CD155 and delivered negative signals to CD4+ T cells expressing CD96 and/or TIGIT receptors. Compromised antigen-presenting function of METTL3hi CD155hi M?? diminished anti-viral T cell responses in vitro and in vivo. LDL and its oxidized form induced the immunosuppressive M?? phenotype. Undifferentiated CAD monocytes had hypermethylated CD155 mRNA,implicating post-transcriptional RNA modifications in the bone-marrow in shaping anti-viral immunity in CAD. View Publication

BACKGROUND Myeloid-derived suppressor cells (MDSCs) can potently inhibit T-cell activity,promote growth and metastasis of tumor and contribute to resistance to immunotherapy. Targeting MDSCs to alleviate their protumor functions and immunosuppressive activities is intimately associated with cancer immunotherapy. Natural killer (NK) cells can engage in crosstalk with multiple myeloid cells to alter adaptive immune responses,triggering T-cell immunity. However,whether the NK-cell-MDSC interaction can modulate the T-cell immune response requires further study. Cryo-thermal therapy could induce the maturation of MDSCs by creating an acute inflammatory environment to elicit a CD4+ Th1-dominant immune response,but the mechanism regulating this process remains unclear. METHODS NK cells were depleted and NKG2D was blocked with monoclonal antibodies in vivo. MDSCs,NK cells and T cells were assessed by flow cytometry and isolated by magnetic-activated cell sorting (MACS). MDSCs and NK cells were cocultured with T cells to determine their immunological function. The transcriptional profiles of MDSCs were measured by qRT-PCR and RNA-sequencing. Isolated NK cells and MDSCs by MACS were cocultured to study the viability and maturation of MDSCs regulated by NK cells. TIMER was used to comprehensively examine the immunological,clinical,and genomic features of tumors. RESULTS NK-cell activation after cryo-thermal therapy decreased MDSC accumulation and reprogrammed immunosuppressive MDSCs toward a mature phenotype to promote T cell antitumor immunity. Furthermore,we discovered that NK cells could kill MDSCs via the NKG2D-NKG2DL axis and promote MDSC maturation by interferon gamma (IFN-$\gamma$) in response to NKG2D. In addition,CD4+ Th1-dominant antitumor immune response was dependent on NKG2D,which promoted the major histocompatibility complex …¡ pathway of MDSCs. High activated NK-cell infiltration and NKG2D level in tumors were positively correlated with better clinical outcomes. CONCLUSIONS Cryo-thermal therapy induces effective CD4+ Th1-dominant antitumor immunity by activating NK cells to reprogram MDSCs,providing a promising therapeutic strategy for cancer immunotherapy. View Publication

G-protein coupled receptor kinases (GRKs) participate in the regulation of chemokine receptors by mediating receptor desensitization. They can be recruited to agonist-activated G-protein coupled receptors (GPCRs) and phosphorylate their intracellular parts,which eventually blocks signal propagation and often induces receptor internalization. However,there is growing evidence that GRKs can also control cellular functions beyond GPCR regulation. Immune cells commonly express two to four members of the GRK family (GRK2,GRK3,GRK5,GRK6) simultaneously,but we have very limited knowledge about their interplay in primary immune cells. In particular,we are missing comprehensive studies comparing the role of this GRK interplay for (a) multiple GPCRs within one leukocyte type,and (b) one specific GPCR between several immune cell subsets. To address this issue,we generated mouse models of single,combinatorial and complete GRK knockouts in four primary immune cell types (neutrophils,T cells,B cells and dendritic cells) and systematically addressed the functional consequences on GPCR-controlled cell migration and tissue localization. Our study shows that combinatorial depletions of GRKs have pleiotropic and cell-type specific effects in leukocytes,many of which could not be predicted. Neutrophils lacking all four GRK family members show increased chemotactic migration responses to a wide range of GPCR ligands,whereas combinatorial GRK depletions in other immune cell types lead to pro- and anti-migratory responses. Combined depletion of GRK2 and GRK6 in T cells and B cells shows distinct functional outcomes for (a) one GPCR type in different cell types,and (b) different GPCRs in one cell type. These GPCR-type and cell-type specific effects reflect in altered lymphocyte chemotaxis in vitro and localization in vivo. Lastly,we provide evidence that complete GRK deficiency impairs dendritic cell homeostasis,which unexpectedly results from defective dendritic cell differentiation and maturation in vitro and in vivo. Together,our findings demonstrate the complexity of GRK functions in immune cells,which go beyond GPCR desensitization in specific leukocyte types. Furthermore,they highlight the need for studying GRK functions in primary immune cells to address their specific roles in each leukocyte subset. View Publication

BACKGROUND Ageing is a complex phenomenon that leads to decreased proliferative activity,loss of function of the cells,and cellular senescence. Senescence of the immune system exacerbates individual's immune response,both humoral and cellular but increases the frequency of infections. We hypothesized that physiological ageing of adaptive immune system occurs in recipients of allogeneic hematopoietic cells transplant (allo-HCT) at faster rate when compared to their respective donors since the small number of donor cells undergo immense proliferative stress restoring recipients hematopoiesis. We compared molecular characterizations of ageing between recipients and donors of allo-HCT: telomeric length and immunophenotypic changes in main lymphocyte subsets - CD4+,CD8+,CD19+,CD56+. RESULTS Median telomeric length (TL) of CD8+ lymphocytes was significantly longer in donors compared to recipients (on average 2,1 kb and 1,7 kb respectively,p??=??0,02). Similar trends were observed for CD4+ and CD19+ although the results did not reach statistical significance. We have also found trends in the immunophenotype between recipients and donors in the subpopulations of CD4+ (na{\{i}}ve and effector memory) CD8+ Eomes+ and B-lymphocytes (B1 and B2). Lower infection risk recipients had also a significantly greater percentage of NK cells (22 3%) than high-risk patients (9 3%) p??=??0 04. CONCLUSION Our data do not support the initial hypothesis of accelerated aging in the long term all-HCT recipients with the exception of the recipients lymphocytes (mainly CD8+) which present some molecular features characteristic for physiological ageing (telomeric shortening immunophenotype) when compared to their respective donors. However a history of lower infection numbers in HCT recipients seems to be associated with increased percentage of NK cells. The history of GVHD seems not to affect the rate of ageing. Therefore it is safe to conclude that the observed subtle differences between recipients' and donors' cells result mainly from the proliferative stress in the early period after allo-HCT and the difference between hosts' and recipients' microenvironments." View Publication