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BACKGROUND Thrombocytopenia leading to life-threatening excessive bleeding can be treated by platelet transfusion. Currently,such treatments are totally dependent on donor-derived platelets. To support future applications in the use of in vitro-derived platelets,we sought to identify genes whose manipulation might improve the efficiency of megakaryocyte production and resulting hemostatic effectiveness. Disruption of Lyn kinase has previously been shown to improve cell survival,megakaryocyte ploidy and TPO-mediated activation in mice,but its role in human megakaryocytes and platelets has not been examined. METHODS To analyze the role of Lyn at defined differentiation stages during human megakaryocyte differentiation,conditional Lyn-deficient cells were generated using CRISPR/Cas9 technology in iPS cells. The efficiency of Lyn-deficient megakaryocytes to differentiate and become activated in response to a range of platelet agonists was analyzed in iPSC-derived megakaryocytes. RESULTS Temporally controlled deletion of Lyn improved the in vitro differentiation of hematopoietic progenitor cells into mature megakaryocytes,as measured by the rate and extent of appearance of CD41+ CD42+ cells. Lyn-deficient megakaryocytes also demonstrated improved hemostatic effectiveness,as reported by their ability to mediate clot formation in rotational thromboelastometry. Finally,Lyn-deficient megakaryocytes produced increased numbers of platelet-like particles (PLP) in vitro. CONCLUSIONS Conditional deletion of Lyn kinase increases the hemostatic effectiveness of megakaryocytes and their progeny as well as improving their yield. Adoption of this system during generation of in vitro-derived platelets may contribute to both their efficiency of production and their ability to support hemostasis. View Publication

Proton export is often considered a detoxifying process in animal cells,with monocarboxylate symporters coexporting excessive lactate and protons during glycolysis or the Warburg effect. We report a novel mechanism by which lactate/H+ export is sufficient to induce cell growth. Increased intracellular pH selectively activates catalysis by key metabolic gatekeeper enzymes HK1/PKM2/G6PDH,thereby enhancing glycolytic and pentose phosphate pathway carbon flux. The result is increased nucleotide levels,NADPH/NADP+ ratio,and cell proliferation. Simply increasing the lactate/proton symporter monocarboxylate transporter 4 (MCT4) or the sodium-proton antiporter NHE1 was sufficient to increase intracellular pH and give normal hematopoietic cells a significant competitive growth advantage in vivo. This process does not require additional cytokine triggers and is exploited in malignancy,where leukemogenic mutations epigenetically increase MCT4. Inhibiting MCT4 decreased intracellular pH and carbon flux and eliminated acute myeloid leukemia-initiating cells in mice without cytotoxic chemotherapy. Intracellular alkalization is a primitive mechanism by which proton partitioning can directly reprogram carbon metabolism for cell growth. 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

Activated neutrophil-derived exosomes reportedly contribute to the proliferation of airway smooth muscle cells (ASMCs),thereby aggravating the airway wall remodeling during asthma; however,the specific mechanism remains unclear. Lipopolysaccharide (LPS)-EXO and si-CRNDE-EXO were extracted from the media of human neutrophils treated with LPS and LPS??+??si-CRNDE (a siRNA targets long non-coding RNA CRNDE),respectively. Human ASMCs were co-cultured with LPS-EXO or si-CRNDE-EXO,and cell viability,proliferation and migration were measured. The interplay of colorectal neoplasia differentially expressed (CRNDE),inhibitor of nuclear factor kappa B kinase subunit beta (IKK$\beta$) and nuclear receptor subfamily 2 group C member 2 (TAK1) was explored using RNA immunoprecipitation (RIP) and Co-IP assays. A mouse model of asthma was induced using ovalbumin. CRNDE was upregulated in LPS-EXO and successfully transferred from LPS-treated neutrophils to ASMCs through exosome. Mechanically,CRNDE loaded in LPS-EXO reinforced TAK1-mediated IKK$\beta$ phosphorylation,thereby activating the nuclear factor kappa B (NF-$\kappa$B) pathway. Functionally,silencing CRNDE in LPS-EXO,an IKK$\beta$ inhibitor,and an NF-$\kappa$B inhibitor all removed the upregulation of cell viability,proliferation and migration induced by LPS-EXO in ASMCs. In the end,the in vivo experiment demonstrated that CRNDE knockdown in neutrophils effectively reduced the thickness of bronchial smooth muscle in a mouse model for asthma. Activated neutrophils-derived CRNDE was transferred to ASMCs through exosomes and activated the NF-$\kappa$B pathway by enhancing IKK$\beta$ phosphorylation. The latter promoted the proliferation and migration of ASMCs and then contributed to airway remodeling in asthma. View Publication

OBJECTIVE Tissue-resident memory T cells (TRM) are vital immune sentinels that provide protective immunity. While hepatic CD8+ TRM have been well described,little is known about the location,phenotype and function of CD4+ TRM. DESIGN We used multiparametric flow cytometry,histological assessment and novel human tissue coculture systems to interrogate the ex vivo phenotype,function and generation of the intrahepatic CD4+ T-cell compartment. We also used leukocytes isolated from human leukocyte antigen (HLA)-disparate liver allografts to assess long-term retention. RESULTS Hepatic CD4+ T cells were delineated into three distinct populations based on CD69 expression: CD69-,CD69INT and CD69HI. CD69HICD4+ cells were identified as tissue-resident CD4+ T cells on the basis of their exclusion from the circulation,phenotypical profile (CXCR6+CD49a+S1PR1-PD-1+) and long-term persistence within the pool of donor-derived leukcoocytes in HLA-disparate liver allografts. CD69HICD4+ T cells produced robust type 1 polyfunctional cytokine responses on stimulation. Conversely,CD69INTCD4+ T cells represented a more heterogenous population containing cells with a more activated phenotype,a distinct chemokine receptor profile (CX3CR1+CXCR3+CXCR1+) and a bias towards interleukin-4 production. While CD69INTCD4+ T cells could be found in the circulation and lymph nodes,these cells also formed part of the long-term resident pool,persisting in HLA-mismatched allografts. Notably,frequencies of CD69INTCD4+ T cells correlated with necroinflammatory scores in chronic hepatitis B infection. Finally,we demonstrated that interaction with hepatic epithelia was sufficient to generate CD69INTCD4+ T cells,while additional signals from the liver microenvironment were required to generate liver-resident CD69HICD4+ T cells. CONCLUSIONS High and intermediate CD69 expressions mark human hepatic CD4+ TRM and a novel functionally distinct recirculating population,respectively,both shaped by the liver microenvironment to achieve diverse immunosurveillance. View Publication

We hypothesized that combining adoptively transferred autologous T cells with a cancer vaccine strategy would enhance therapeutic efficacy by adding antimyeloma idiotype (Id)-keyhole limpet hemocyanin (KLH) vaccine to vaccine-specific costimulated T cells. In this randomized phase 2 trial,patients received either control (KLH only) or Id-KLH vaccine,autologous transplantation,vaccine-specific costimulated T cells expanded ex vivo,and 2 booster doses of assigned vaccine. In 36 patients (KLH,n = 20; Id-KLH,n = 16),no dose-limiting toxicity was seen. At last evaluation,6 (30%) and 8 patients (50%) had achieved complete remission in KLH-only and Id-KLH arms,respectively (P = .22),and no difference in 3-year progression-free survival was observed (59% and 56%,respectively; P = .32). In a 594 Nanostring nCounter gene panel analyzed for immune reconstitution (IR),compared with patients receiving KLH only,there was a greater change in IR genes in T cells in those receiving Id-KLH relative to baseline. Specifically,upregulation of genes associated with activation,effector function induction,and memory CD8+ T-cell generation after Id-KLH but not after KLH control vaccination was observed. Similarly,in responding patients across both arms,upregulation of genes associated with T-cell activation was seen. At baseline,all patients had greater expression of CD8+ T-cell exhaustion markers. These changes were associated with functional Id-specific immune responses in a subset of patients receiving Id-KLH. In conclusion,in this combination immunotherapy approach,we observed significantly more robust IR in CD4+ and CD8+ T cells in the Id-KLH arm,supporting further investigation of vaccine and adoptive immunotherapy strategies. This trial was registered at www.clinicaltrials.gov as #NCT01426828. 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

Traumatic injuries,such as burn,are often complicated by ethanol intoxication at the time of injury. This leads to a myriad of complications and post-burn pathologies exacerbated by aberrant immune responses. Recent findings suggest that immune cell dysfunction in the gastrointestinal system is particularly important in deleterious outcomes associated with burn injuries. In particular,intoxication at the time of burn injury leads to compromised intestinal T cell responses,which can diminish intestinal immunity and promote bacterial translocation,allowing for increased secondary infections in the injured host and associated sequelae,such as multiple organ failure and sepsis. Regulatory T cells (Treg) have been identified as important mediators of suppressing effector T cell function. Therefore,the goal of this study was to assess the effects of ethanol intoxication and burn injury on Treg populations in small intestinal immune organs. We also evaluated the suppressive capability of Tregs isolated from injured animals. Male C57BL/6 mice were gavaged with 2.9?Šg/kg ethanol before receiving a ˆ¼12.5% total body surface area scald burn. One day after injury,we identified a significant increase in Tregs number in small intestine Peyer's patches (ˆ¼?—1.5) and lamina propria (ˆ¼?—2). Tregs-producing cytokine IL-10 were also increased in both tissues. Finally,Tregs isolated from ethanol and burn-injured mice were able to suppress proliferation of effector T cells to a greater degree than sham vehicle Tregs. This was accompanied by increased levels of IL-10 and decreased levels of pro-proliferative cytokine IL-2 in cultures containing ethanol + burn Tregs compared with sham Tregs. These findings suggest that Treg populations are increased in intestinal tissues 1 day following ethanol intoxication and burn injury. Tregs isolated from ethanol and burn-injured animals also exhibit a greater suppression of effector T cell proliferation,which may contribute to altered T cell responses following injury. 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

The clinical evolution of patients with chronic Chagas disease (CCD) is mainly associated with an excessive inflammation and a defective immunomodulatory profile caused by the interaction between T. cruzi and the host. Regulatory B (Breg) cells exert immune suppression mostly through IL-10 production (B10 cells),but also through IL-10-independent mechanisms. Previously,we demonstrated that CCD patients with cardiomyopathy show changes in the ex vivo Breg cell phenotypic distribution although maintain IL-10 production capacity. Here,we sought to identify potential alterations on Breg cells upon in vitro stimulation. Isolated B cells from CCD patients with or without cardiomyopathy and non-infected (NI) donors were stimulated with T. cruzi lysate or CpG + CD40L,and characterized by flow cytometry based on the expression of CD24,CD27,CD38,and the regulatory molecules IL-10 and PD-L1. IL-10 and IL-17 secretion in the supernatant of B cells was evaluated by ELISA. Data showed that T. cruzi stimulation diminished the expression of CD24 and CD38 on CD27- B cells while reducing the percentage of CD24high inside CD27+ B cells. Furthermore,T. cruzi induced a regulatory B cell phenotype by increasing B10 cells and IL-10 secretion in all the groups. The innate-like B10 cells expansion observed in patients with cardiomyopathy would be associated with CD27- B10 cell subsets,while no predominant phenotype was found in the other groups. Patients with cardiomyopathy also displayed higher IL-17 secretion levels in T. cruzi-activated B cells. CpG + CD40L stimulation revealed that B cells from CCD patients and NI donors had the same ability to differentiate into B10 cells and secrete IL-10 in vitro. Additionally,CCD patients showed an increased frequency of CD24-CD27- B cells and a reduction in the percentage of CD24highCD27+ Breg cells,which appeared to be inversely correlated with the presence of T. cruzi DNA in blood. Finally,CCD patients exhibited a higher frequency of PD-L1+ B cells in T. cruzi-stimulated samples,suggesting that IL-10-independent mechanisms could also be tangled in the control of inflammation. Altogether,our results provide evidence about the potential role of Breg cells in the immune response developed against T. cruzi and its contribution to chronic Chagas cardiomyopathy. View Publication

RNA-targeting CRISPR-Cas13 proteins have recently emerged as a powerful platform to modulate gene expression outcomes. However,protein and CRISPR RNA (crRNA) delivery in human cells can be challenging with rapid crRNA degradation yielding transient knockdown. Here we compare several chemical RNA modifications at different positions to identify synthetic crRNAs that improve RNA targeting efficiency and half-life in human cells. We show that co-delivery of modified crRNAs and recombinant Cas13 enzyme in ribonucleoprotein (RNP) complexes can alter gene expression in primary CD4+ and CD8+ T cells. This system represents a robust and efficient method to modulate transcripts without genetic manipulation. View Publication

Neutrophils (PMNs) contain and release a powerful arsenal of mediators,including several granular enzymes,reactive oxygen species (ROS) and neutrophil extracellular traps (NETs). Although airway neutrophilia is associated with severity,poor response to glucocorticoids and exacerbations,the pathophysiological role of neutrophils in asthma remains poorly understood. Twenty-four patients with asthma and 22 healthy controls (HCs) were prospectively recruited. Highly purified peripheral blood neutrophils (> 99%) were evaluated for ROS production and activation status upon stimulation with lipopolysaccharide (LPS),N-formylmethionyl-leucyl-phenylalanine (fMLP) and phorbol 12-myristate 13-acetate (PMA). Plasma levels of myeloperoxidase (MPO),CXCL8,matrix metalloproteinase-9 (MMP-9),granulocyte-monocyte colony-stimulating factor (GM-CSF) and vascular endothelial growth factor (VEGF-A) were measured by ELISA. Plasma concentrations of citrullinated histone H3 (CitH3) and circulating free DNA (dsDNA) were evaluated as NET biomarkers. Activated PMNs from asthmatics displayed reduced ROS production and activation status compared to HCs. Plasma levels of MPO,MMP-9 and CXCL8 were increased in asthmatics compared to HCs. CitH3 and dsDNA plasma levels were increased in asthmatics compared to controls and the CitH3 concentrations were inversely correlated to the % decrease in FEV1/FVC in asthmatics. These findings indicate that neutrophils and their mediators could have an active role in asthma pathophysiology. View Publication