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The efficacy of immunotherapy is often hindered by the suppression of immune responses via the tumor microenvironment (TME). The presence of cancer cells forces other proximal non-cancerous cells to support tumor growth and persistence. A clear example of this cancerous-to-non-cancerous communication is represented by the accumulation of myeloid-derived suppressor cells (MDSCs) within the TME. Several studies have convergently shown that the overexpression of DNA-methyl-transferase-1 (DNMT1) in these cells results in protection from necroptosis and enhanced accumulation in vivo. Conversely,targeting DNMT1 through hypo-methylating agents has shown promising therapeutic potential by not only reducing the levels of MDSCs but also enhancing cancer immunogenicity and the efficacy of immune checkpoint inhibitors (ICI). Methods: Murine 4T1 (triple-negative breast cancer (TNBC)) and CT26 (colon carcinoma) cell lines were cultured under standard conditions and used to generate tumor models in BALB/c mice. An oncolytic adenovirus expressing a DNMT1-targeting short hairpin RNA (OAd.shDNMT1) was engineered and validated for DNMT1 knockdown and genome-wide methylation reduction. Small extracellular vesicles (sEVs) were isolated from virus-infected cancer cells and characterized for RNA content and uptake by MDSCs. MDSC differentiation and suppressive function were assessed in vitro using flow cytometry and co-culture assays with murine splenocytes. In vivo,tumor-bearing mice received intratumoral OAd.shDNMT1,systemic decitabine,or immune checkpoint inhibitors (anti-Programmed cell Death protein-1),and tumor growth,immune infiltration,and systemic MDSC levels were evaluated. Results: In this study,we report that,by using virally infected TNBC murine cells as a source for shDNMT1-loaded sEVs,OAd.shDNMT1 successfully reduced MDSC levels in vitro and in vivo. Furthermore,the co-administration with ICI resulted in a significant tumor growth reduction in mice bearing poorly immunogenic TNBC 4T1 cells. Also,our treatment promoted antitumor immunity,prolonged survival,and complete tumor eradication in modestly immunogenic colon CT26 cancer cells. Conclusions: This multifaceted strategy,based on OV-mediated immune stimulation and reduction of MDSC levels via sEVs,may improve clinical outcomes and the success of immuno-based regimens for patients facing MDSC-rich and highly aggressive cancer subtypes. View Publication

In dynamic light microscopy applications,imaging specimens from multiple angles while maintaining controlled temperature conditions is crucial for comprehensive and accurate analysis. To address these challenges,we present iCAT,an open-source multifunctional accessory designed to enhance light microscopy. It enables specimen rotation along the axial plane,incorporates built-in modules for precise temperature control,features an integrated LED,and includes a camera for real-time specimen monitoring. It can be easily 3D-printed and assembled using readily available electrical components. Combined with any up-right microscope,this versatile device allows researchers to capture detailed images and videos of organoid cultures and live or fixed specimens,such as C. elegans,zebrafish,drosophila,or mouse embryos. The potential applications of iCAT in investigating dynamic cellular processes and complex developmental phenomena are vast,inspiring researchers to explore its possibilities and push the boundaries of biological research. iCAT,an open-source,3D-printable microscopy accessory,enables axial specimen rotation,temperature control,and live monitoring for high-resolution imaging of organoids and diverse model organisms. View Publication

Adult T-cell leukemia (ATL) caused by human T-cell leukemia virus type 1 (HTLV-1) infection,occurs in 2% to 4% of the HTLV-1 carriers with a long latent period,suggesting that additional alterations participate in the development of ATL. To characterize and identify novel markers of ATL,we examined the expression profiles of more than 12 000 genes in 8 cases of acute-type ATL using microarray. One hundred ninety-two genes containing interleukin 2 (IL-2) receptor alpha were up-regulated more than 2-fold compared with CD4(+) and CD4(+)CD45RO(+) T cells,and tumor suppressor in lung cancer 1 (TSLC1),caveolin 1,and prostaglandin D2 synthase showed increased expression of more than 30-fold. TSLC1 is a cell adhesion molecule originally identified as a tumor suppressor in the lung but lacks its expression in normal or activated T cells. We confirmed ectopic expression of the TSLC1 in all acute-type ATL cells and in 7 of 10 ATL- or HTLV-1-infected T-cell lines. Introduction of TSLC1 into a human ATL cell line ED enhanced both self-aggregation and adhesion ability to vascular endothelial cells. These results suggested that the ectopic expression of TSLC1 could provide a novel marker for acute-type ATL and may participate in tissue invasion,a characteristic feature of the malignant ATL cells. View Publication

The ectopic expression of transcription factors can reprogram differentiated tissue cells into induced pluripotent stem cells. However,this is a slow and inefficient process,depending on the simultaneous delivery of multiple genes encoding essential reprogramming factors and on their sustained expression in target cells. Moreover,once cell reprogramming is accomplished,these exogenous reprogramming factors should be replaced with their endogenous counterparts for establishing autoregulated pluripotency. Complete and designed removal of the exogenous genes from the reprogrammed cells would be an ideal option for satisfying this latter requisite as well as for minimizing the risk of malignant cell transformation. However,no single gene delivery/expression system has ever been equipped with these contradictory characteristics. Here we report the development of a novel replication-defective and persistent Sendai virus (SeVdp) vector based on a noncytopathic variant virus,which fulfills all of these requirements for cell reprogramming. The SeVdp vector could accommodate up to four exogenous genes,deliver them efficiently into various mammalian cells (including primary tissue cells and human hematopoietic stem cells) and express them stably in the cytoplasm at a prefixed balance. Furthermore,interfering with viral transcription/replication using siRNA could erase the genomic RNA of SeVdp vector from the target cells quickly and thoroughly. A SeVdp vector installed with Oct4/Sox2/Klf4/c-Myc could reprogram mouse primary fibroblasts quite efficiently; ∼1% of the cells were reprogrammed to Nanog-positive induced pluripotent stem cells without chromosomal gene integration. Thus,this SeVdp vector has potential as a tool for advanced cell reprogramming and for stem cell research. View Publication

Many drug-resistant tumors and cancer stem cells (CSC) express elevated levels of CD44 receptor,a cellular glycoprotein binding hyaluronic acid (HA). Here,we report the synthesis of nanogel-drug conjugates based on membranotropic cholesteryl-HA (CHA) for efficient targeting and suppression of drug-resistant tumors. These conjugates significantly increased the bioavailability of poorly soluble drugs with previously reported activity against CSC,such as etoposide,salinomycin,and curcumin. The small nanogel particles (diameter 20-40 nm) with a hydrophobic core and high drug loads (up to 20%) formed after ultrasonication and demonstrated a sustained drug release following the hydrolysis of biodegradable ester linkage. Importantly,CHA-drug nanogels demonstrated 2-7 times higher cytotoxicity in CD44-expressing drug-resistant human breast and pancreatic adenocarcinoma cells compared to that of free drugs and nonmodified HA-drug conjugates. These nanogels were efficiently internalized via CD44 receptor-mediated endocytosis and simultaneous interaction with the cancer cell membrane. Anchoring by cholesterol moieties in the cellular membrane after nanogel unfolding evidently caused more efficient drug accumulation in cancer cells compared to that in nonmodified HA-drug conjugates. CHA-drug nanogels were able to penetrate multicellular cancer spheroids and displayed a higher cytotoxic effect in the system modeling tumor environment than both free drugs and HA-drug conjugates. In conclusion,the proposed design of nanogel-drug conjugates allowed us to significantly enhance drug bioavailability,cancer cell targeting,and the treatment efficacy against drug-resistant cancer cells and multicellular spheroids. View Publication

Chlamydia infection and disease are endemic in free-ranging koalas. Antibiotics remain the front line treatment for Chlamydia in koalas,despite their rates of treatment failure and adverse gut dysbiosis outcomes. A Chlamydia vaccine for koalas has shown promise for replacing antibiotic treatment in mild ocular Chlamydia disease. In more severe disease presentations that require antibiotic intervention,the effect of vaccinating during antibiotic use is not currently known. This study investigated whether a productive immune response could be induced by vaccinating koalas during antibiotic treatment for Chlamydia-induced cystitis. Plasma IgG antibody levels against the C. pecorum major outer membrane protein (MOMP) dropped during antibiotic treatment in both vaccinated and unvaccinated koalas. Post-treatment,IgG levels recovered. The IgG antibodies from naturally-infected,vaccinated koalas recognised a greater proportion of the MOMP protein compared to their naturally-infected,unvaccinated counterparts. Furthermore,peripheral blood mononuclear cell gene expression revealed an up-regulation in genes related to neutrophil degranulation in vaccinated koalas during the first month post-vaccination. These findings show that vaccination of koalas while they are being treated with antibiotics for cystitis can result in the generation of a productive immune response,in the form of increased and expanded IgG production and host response through neutrophil degranulation. View Publication

Hepatocyte death during acetaminophen (APAP) intoxication elicits a reactive inflammatory response,with hepatic recruitment of neutrophils and monocytes,which further aggravates liver injury. Neutrophil elastase (NE),secreted by activated neutrophils,carries degradative and cytotoxic functions and maintains a proinflammatory state. We investigated NE as a therapeutic target in acetaminophen-induced liver injury (AILI). C57BL/6 mice were administered a toxic dose of APAP,2 h prior to receiving the NE inhibitor sivelestat,N-acetylcysteine (NAC),or a combination therapy,and were euthanized after 24 and 48 h. Upon APAP overdose,neutrophils and monocytes infiltrate the injured liver,accompanied by increased levels of NE. Combination therapy of NAC and sivelestat significantly limits liver damage,as evidenced by lower serum transaminase levels and less hepatic necrosis compared to mice that received APAP only,and this to a greater extent than NAC monotherapy. Lower hepatic expression of proinflammatory markers was observed in the combination treatment group,and flow cytometry revealed significantly less monocyte influx in livers from mice treated with the combination therapy,compared to untreated mice and mice treated with NAC only. The potential of NE to induce leukocyte migration was confirmed in vitro. Importantly,sivelestat did not impair hepatic repair. In conclusion,combination of NE inhibition with sivelestat and NAC dampens the inflammatory response and reduces liver damage following APAP overdose. This strategy exceeds the standard of care and might represent a novel therapeutic option for AILI. View Publication

Efficient in vivo selection increases survival of gene-corrected hematopoietic stem cells (HSCs) and protects hematopoiesis,even if initial gene transfer efficiency is low. Moreover,selection of a limited number of transduced HSCs lowers the number of cell clones at risk of gene activation by insertional mutagenesis. However,a limited clonal repertoire greatly increases the proliferation stress of each individual clone. Therefore,understanding the impact of in vivo selection on proliferation and lineage differentiation of stem-cell clones is essential for its clinical use. We established minimal cell and drug dosage requirements for selection of P140K mutant O6-methylguanine-DNA-methyltransferase (MGMT P140K)-expressing HSCs and monitored their differentiation potential and clonality under long-term selective stress. Up to 17 administrations of O6-benzylguanine (O6-BG) and 1,3-bis(2-chloroethyl)-1-nitroso-urea (BCNU) did not impair long-term differentiation and proliferation of MGMT P140K-expressing stem-cell clones in mice that underwent serial transplantation and did not lead to clonal exhaustion. Interestingly,not all gene-modified hematopoietic repopulating cell clones were efficiently selectable. Our studies demonstrate that the normal function of murine hematopoietic stem and progenitor cells is not compromised by reduced-intensity long-term in vivo selection,thus underscoring the potential value of MGMT P140K selection for clinical gene therapy. View Publication

Human induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM)-based assays are emerging as a promising tool for the in vitro preclinical screening of QT interval-prolonging side effects of drugs in development. A major impediment to the widespread use of human iPSC-CM assays is the low throughput of the currently available electrophysiological tools. To test the precision and applicability of the near-infrared fluorescent voltage-sensitive dye 1-(4-sulfanatobutyl)-4-β[2-(di-n-butylamino)-6-naphthyl]butadienylquinolinium betaine (di-4-ANBDQBS) for moderate-throughput electrophysiological analyses,we compared simultaneous transmembrane voltage and optical action potential (AP) recordings in human iPSC-CM loaded with di-4-ANBDQBS. Optical AP recordings tracked transmembrane voltage with high precision,generating nearly identical values for AP duration (AP durations at 10%,50%,and 90% repolarization). Human iPSC-CMs tolerated repeated laser exposure,with stable optical AP parameters recorded over a 30-min study period. Optical AP recordings appropriately tracked changes in repolarization induced by pharmacological manipulation. Finally,di-4-ANBDQBS allowed for moderate-throughput analyses,increasing throughput textgreater10-fold over the traditional patch-clamp technique. We conclude that the voltage-sensitive dye di-4-ANBDQBS allows for high-precision optical AP measurements that markedly increase the throughput for electrophysiological characterization of human iPSC-CMs. View Publication

Bone marrow mesenchymal stem cells (MSC) have potent immunosuppressive properties and have been advocated for therapeutic use in humans. The nature of their suppressive capacity is poorly understood but is said to be a primitive stem cell function. Demonstration that adult stromal cells such as fibroblasts (Fb) can modulate T cells would have important implications for immunoregulation and cellular therapy. In this report,we show that dermal Fb inhibit allogeneic T cell activation by autologously derived cutaneous APCs and other stimulators. Fb mediate suppression through soluble factors,but this is critically dependent on IFN-gamma from activated T cells. IFN-gamma induces IDO in Fb,and accelerated tryptophan metabolism is at least partly responsible for suppression of T cell proliferation. T cell suppression is reversible,and transient exposure to Fb during activation reprograms T cells,increasing IL-4 and IL-10 secretion upon restimulation. Increased Th2 polarization by stromal cells is associated with amelioration of pathological changes in a human model of graft-vs-host disease. Dermal Fb are highly clonogenic in vitro,suggesting that Fb-mediated immunosuppression is not due to outgrowth of rare MSC,although dermal Fb remain difficult to distinguish from MSC by phenotype or transdifferentiation capacity. These results suggest that immunosuppression is a general property of stromal cells and that dermal Fb may provide an alternative and accessible source of cellular therapy. View Publication

Langerhans cells (LCs) constitute a subset of DCs that initiate immune responses in skin. Using leprosy as a model,we investigated whether expression of CD1a and langerin,an LC-specific C-type lectin,imparts a specific functional role to LCs. LC-like DCs and freshly isolated epidermal LCs presented nonpeptide antigens of Mycobacterium leprae to T cell clones derived from a leprosy patient in a CD1a-restricted and langerin-dependent manner. LC-like DCs were more efficient at CD1a-restricted antigen presentation than monocyte-derived DCs. LCs in leprosy lesions coexpress CD1a and langerin,placing LCs in position to efficiently present a subset of antigens to T cells as part of the host response to human infectious disease. View Publication

The enteric nervous system (ENS) is recognized as a second brain because of its complexity and its largely autonomic control of bowel function. Recent progress in studying the interactions between the ENS and the central nervous system (CNS) has implicated alterations of the gut/brain axis as a possible mechanism in the pathophysiology of autism spectrum disorders (ASDs),Parkinson's disease (PD) and other human CNS disorders,whereas the underlying mechanisms are largely unknown because of the lack of good model systems. Human induced pluripotent stem cells (hiPSCs) have the ability to proliferate indefinitely and differentiate into cells of all three germ layers,thus making iPSCs an ideal source of cells for disease modelling and cell therapy. Here,hiPSCs were induced to differentiate into neural crest stem cells (NCSCs) efficiently. When co-cultured with smooth muscle layers of ganglionic gut tissue,the NCSCs differentiated into different subtypes of mature enteric-like neurons expressing nitric oxide synthase (nNOS),vasoactive intestinal polypeptide (VIP),choline acetyltransferase (ChAT) or calretinin with typical electrophysiological characteristics of functional neurons. Furthermore,when they were transplanted into aneural or aganglionic chick,mouse or human gut tissues in ovo,in vitro or in vivo,hiPSC-derived NCSCs showed extensive migration and neural differentiation capacity,generating neurons and glial cells that expressed phenotypic markers characteristic of the enteric nervous system. Our results indicate that enteric NCSCs derived from hiPSCs supply a powerful tool for studying the pathogenesis of gastrointestinal disorders and brain/gut dysfunction and represent a potentially ideal cell source for enteric neural transplantation treatments.Molecular Psychiatry advance online publication,25 October 2016; doi:10.1038/mp.2016.191. View Publication