Publications by authors named "Donald A Cohen"

γδ T cells are resident in visceral adipose tissue (VAT) where they show an age-associated increase in numbers and contribute to local and systemic chronic inflammation. However, regulation of this population and mechanisms for the age-dependent accumulation are not known. In this study, we identified a progressive trend of γδ T cell accumulation in VAT over the lifespan in mice and explored physiological mechanisms contributing to accumulation.

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Adipose tissue dysfunction is strongly linked to the development of chronic inflammation and cardiometabolic disorders in aging. While much attention has been given to the role of resident adipose tissue immune cells in the disruption of homeostasis in obesity, age-specific effects remain understudied. Here, we identified and characterized a population of γδ T cells, which show unique age-dependent accumulation in the visceral adipose tissue (VAT) of both mice and humans.

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Objectives: Visceral adipose tissue is a major site for expression of proinflammatory and procoagulant genes during acute systemic inflammation. In this study, we tested whether the loss of fat mass by dietary restriction would remove the major source of these factors resulting in improved tolerance to sepsis and endotoxemia.

Design: Prospective, laboratory controlled experiments.

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From birth to adulthood, the gut microbiota matures from a simple community dominated by a few major bacterial groups into a highly diverse ecosystem that provides both benefits and challenges to the host. Currently there is great interest in identifying environmental and host factors that shape the development of our gut microbiota. Breast milk is a rich source of maternal antibodies, which provide the first source of adaptive immunity in the newborn's intestinal tract.

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The virulence protein YopM of the plague bacterium Yersinia pestis has different dominant effects in liver and spleen. Previous studies focused on spleen, where YopM inhibits accumulation of inflammatory dendritic cells. In the present study we focused on liver, where PMN function may be directly undermined by YopM without changes in inflammatory cell numbers in the initial days of infection, and foci of inflammation are easily identified.

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Activation of the Wnt/β-catenin pathway has been observed in at least 1/3 of hepatocellular carcinomas (HCC), and a significant number of these have mutations in the β-catenin gene. Therefore, effective inhibition of this pathway could provide a novel method to treat HCC. The purposed of this study was to determine whether FH535, which was previously shown to block the β-catenin pathway, could inhibit β-catenin activation of target genes and inhibit proliferation of Liver Cancer Stem Cells (LCSC) and HCC cell lines.

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In recent years, the lipoaspirate collected from adipose tissue has been seen as a valuable source of adipose-derived mesenchymal stem cells for autologous cellular therapy. For multiple applications, adipose-derived mesenchymal stem cells are isolated from the stromal vascular fraction (SVF) of adipose tissue. Because the fresh stromal vascular fraction typically contains a heterogeneous mixture of cells, determining cell concentration and viability is a crucial step in preparing fraction samples for downstream processing.

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Maintenance of intestinal homeostasis requires a healthy relationship between the commensal gut microbiota and the host immune system. Breast milk supplies the first source of antigen-specific immune protection in the gastrointestinal tract of suckling mammals, in the form of secretory IgA (SIgA). SIgA is transported across glandular and mucosal epithelial cells into external secretions by the polymeric Ig receptor (pIgR).

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Background: Production of inflammatory cytokines by mesenteric adipose tissue (MAT) has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Animal models of colitis have demonstrated inflammatory changes within MAT, but it is unclear if these changes occur in isolation or as part of a systemic adipose tissue response. It is also unknown what cell types are responsible for cytokine production within MAT.

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Mucosal DCs play a critical role in tissue homeostasis. Several stimuli can induce a mucosal phenotype; however, molecular pathways that regulate development of mucosal DC function are relatively unknown. This study sought to determine whether PPARγ contributes to the development of the "mucosal" phenotype in mouse DCs.

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Background: Deregulated Ras/Raf/mitogen-activated protein kinase and PI3 K/AKT/mTOR signaling pathways are significant in hepatocellular carcinoma proliferation (HCC). In this study we evaluated differences in the antiproliferative effect of dual PI3 K/Akt/mTOR and Ras/Raf/mitogen-activated protein kinase inhibition of non liver cancer stem cell lines (PLC and HuH7) and liver cancer stem cell (LCSC) lines (CD133, CD44, CD24, and aldehyde dehydrogenase 1-positive cells).

Materials And Methods: Flow cytometry was performed on the resulting tumors to identify the LCSC markers CD133, CD44, CD24, and aldehyde dehydrogenase 1.

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Acute myocardial infarction (AMI) triggers mobilization of stem cells from bone marrow (BM) into peripheral blood (PB). Based on our observation that the bioactive sphingophospholipids, sphingosine-1 phosphate (S1P), and ceramide-1 phosphate (C1P) regulate trafficking of hematopoietic stem cells (HSCs), we explored whether they also direct trafficking of non-hematopoietic stem cells (non-HSCs). We detected a 3-6-fold increase in circulating CD34+, CD133+, and CXCR4+ lineage-negative (Lin-)/CD45- cells that are enriched in non-HSCs [including endothelial progenitors (EPCs) and very small embryonic-like stem cells (VSELs)] in PB from AMI patients (P<0.

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YopM is one of the six "effector Yops" of the human-pathogenic Yersinia, but its mechanism has not been defined. After delivery to J774A.1 monocyte-like cells, YopM can rapidly bind and activate the serine/threonine kinases RSK1 and PRK2.

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Background: The pathogenesis of inflammatory bowel disease (IBD) is complex and the need to identify molecular biomarkers is critical. Epithelial cells play a central role in maintaining intestinal homeostasis. We previously identified five "signature" biomarkers in colonic epithelial cells (CEC) that are predictive of disease phenotype in Crohn's disease.

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Dendritic cells (DCs) play an essential role in regulation of immune responses. In the periphery, Ag presentation by DCs is critical for adaptive responses; for this reason, DCs are often targets of adjuvants that enhance vaccine responses. Activated mature DCs enhance B cell activation and differentiation by providing cytokines like BAFF and a proliferation-inducing ligand.

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Background: Hypoadiponectinemia has been associated with states of chronic inflammation in humans. Mesenteric fat hypertrophy and low adiponectin have been described in patients with Crohn's disease. We investigated whether adiponectin and the plant-derived homolog, osmotin, are beneficial in a murine model of colitis.

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Syngeneic graft vs. host disease (SGVHD) was first described as a graft vs. host disease-like syndrome that developed in rats following syngeneic bone marrow transplantation (BMT) and cyclosporin A (CsA) treatment.

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We are using a systemic plague model to identify the cells and pathways that are undermined by the virulence protein YopM of the plague bacterium Yersinia pestis. In this study, we pursued previous findings that Gr1(+) cells are required to selectively limit growth of ΔyopM Y. pestis and that CD11b(+) cells other than polymorphonuclear leukocytes (PMNs) are selectively lost in spleens infected with parent Y.

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Objective: The ischemic myocardium releases multiple chemotactic factors responsible for the mobilization and recruitment of bone marrow-derived cells to injured myocardium. However, the mobilization of primitive pluripotent stem cells (PSCs) enriched in very small embryonic-like stem cells (VSELs) in various cardiac ischemic scenarios is not well understood.

Materials And Methods: Fifty-four ischemic heart disease patients, including subjects with stable angina, non-ST elevation myocardial infarction, and ST elevation myocardial infarction (STEMI) and 12 matched controls were enrolled.

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The murine model of cyclosporine A (CsA)-induced syngeneic graft-versus-host disease (SGVHD) is a bone marrow (BM) transplantation model that develops chronic colon inflammation identical to other murine models of CD4(+) T cell-mediated colitis. Interestingly, SGVHD animals develop chronic liver lesions that are similar to the early peribiliary inflammatory stages of clinical chronic liver disease, which is frequently associated with inflammatory bowel disease (IBD). Therefore, studies were initiated to investigate the chronic liver inflammation that develops in the SGVHD model.

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Treatment of non-small cell lung carcinoma (NSCLC) remains at a disappointingly low success rate. Not only is metastatic spread common in NSCLC, but therapeutic success decreases dramatically once metastases are present. Understanding factors which contribute to poor prognosis in NSCLC is critical for development of more successful therapeutic approaches.

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Tumor-infiltrating myeloid cells (TIMs) support tumor growth by promoting angiogenesis and suppressing antitumor immune responses. CSF-1 receptor (CSF1R) signaling is important for the recruitment of CD11b(+)F4/80(+) tumor-associated macrophages (TAMs) and contributes to myeloid cell-mediated angiogenesis. However, the impact of the CSF1R signaling pathway on other TIM subsets, including CD11b(+)Gr-1(+) myeloid-derived suppressor cells (MDSCs), is unknown.

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YopM, a protein toxin of Yersinia pestis, is necessary for virulence in a mouse model of systemic plague. We previously reported YopM-dependent natural killer (NK) cell depletion from blood and spleen samples of infected mice. However, in this study we found that infection with Y.

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Relapsing fever spirochetes, such as Borrelia hermsii, proliferate to high levels in their hosts' bloodstream until production of IgM against borrelial surface proteins promotes bacterial clearance. The mechanisms by which B. hermsii survives in host blood, as well as the immune mediators that control this infection, remain largely unknown.

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The homeostatic microenvironment in lung is immunosuppressive and interleukin-10 (IL-10) helps maintain this microenvironment. Despite constitutive production of IL-10 in normal lung, macrophages (MØs) and dentritic cells (DCs) remain capable of responding to microorganisms, suggesting that these innate immune cells have a mechanism to override the immunosuppressive effects of IL-10. Prior studies by the authors revealed that Toll-like receptor (TLR) ligands inhibit IL-10 receptor signaling in alveolar macrophages (AMØs), thereby obviating the immunosuppressive activity of IL-10.

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