Project description:IntroductionImmunodeficient mice engrafted with human immune systems support studies of human hematopoiesis and the immune response to human-specific pathogens. A significant limitation of these humanized mouse models is, however, a severely restricted ability of human B cells to undergo class switching and produce antigen-specific IgG after infection or immunization.MethodsIn this study, we have characterized the development and function of human B cells in NOD-scid IL2Rγnull (NSG) mice transgenically expressing human stem cell factor (SCF), granulocyte macrophage colony-stimulating factor (GM-CSF), and IL-3 (NSG-SGM3) following engraftment with human hematopoietic stem cells, autologous fetal liver, and thymic tissues (bone marrow, liver, thymus or BLT model). The NSG-SGM3 BLT mice engraft rapidly with human immune cells and develop T cells, B cells, and myeloid cells.ResultsA higher proportion of human B cells developing in NSG-SGM3 BLT mice had a mature/naive phenotype with a corresponding decrease in immature/transitional human B cells as compared to NSG BLT mice. In addition, NSG-SGM3 BLT mice have higher basal levels of human IgM and IgG as compared with NSG BLT mice. Moreover, dengue virus infection of NSG-SGM3 BLT mice generated higher levels of antigen-specific IgM and IgG, a result not observed in NSG BLT mice.ConclusionsOur studies suggest that NSG-SGM3 BLT mice show improved human B cell development and permit the generation of antigen-specific antibody responses to viral infection.
Project description:In this study, we demonstrate a newly derived mouse model that supports engraftment of human hematopoietic stem cells (HSCs) in the absence of irradiation. We cross the NOD.Cg-Prkdc(scid)Il2rg(tm1Wjl)/SzJ (NSG) strain with the C57BL/6J-Kit(W-41J)/J (C57BL/6.Kit(W41)) strain and engraft, without irradiation, the resulting NBSGW strain with human cord blood CD34+ cells. At 12-weeks postengraftment in NBSGW mice, we observe human cell chimerism in marrow (97% ± 0.4%), peripheral blood (61% ± 2%), and spleen (94% ± 2%) at levels observed with irradiation in NSG mice. We also detected a significant number of glycophorin-A-positive expressing cells in the developing NBSGW marrow. Further, the observed levels of human hematopoietic chimerism mimic those reported for both irradiated NSG and NSG-transgenic strains. This mouse model permits HSC engraftment while avoiding the complicating hematopoietic, gastrointestinal, and neurological side effects associated with irradiation and allows investigators without access to radiation to pursue engraftment studies with human HSCs.
Project description:Pancreatic ductal adenocarcinoma (PDAC) is associated with a high incidence of hepatic metastases, as well as occasional pulmonary metastases. To delineate the potential role of cancer stem cells (CSCs) in PDAC metastasis, human PDAC cells were injected into the spleen of mice. The characteristics and expression of markers associated with CSC and epithelial-mesenchymal transition (EMT) of metastatic cells that developed in the liver and lung were then compared with parental cells. The metastatic cells were polygonal, and larger than parental cells. Metastatic cells also exhibited decreased proliferation and increased adhesion to extracellular matrices, as well as enhanced migration and invasion in vitro and increased metastatic capacity in vivo. The CSC markers ALDH1A1, ABCG2, and nestin were expressed at high levels in metastatic cells and exhibited changes consistent with EMT (eg, decreased E-cadherin expression). Moreover, metastatic cells readily formed spheres in culture and exhibited an increased side population by flow analysis. Nestin and ABCG2 were also expressed at high levels in metastatic lesions from PDAC patients, and silencing nestin with shRNA in PDAC cells derived from lung metastases resulted in a marked decrease in the capacity of the cells to form spheres and to yield pulmonary or hepatic metastases. Thus, the metastatic potential of human PDAC cells correlates with CSCs and with EMT characteristics and is dependent on nestin expression.
Project description:Human hematolymphoid mice have become valuable tools for the study of human hematopoiesis and uniquely human pathogens in vivo. Recent improvements in xenorecipient strains allow for long-term reconstitution with a human immune system. However, certain hematopoietic lineages, for example, the myeloid lineage, are underrepresented, possibly because of the limited cross-reactivity of murine and human cytokines. Therefore, we created a nonobese diabetic/severe combined immunodeficiency/interleukin-2 receptor-γ-null (NOD-SCID IL2Rγ(null)) mouse strain that expressed human stem cell factor, granulocyte-macrophage colony-stimulating factor, and interleukin-3, termed NSG-SGM3. Transplantation of CD34(+) human hematopoietic stem cells into NSG-SGM3 mice led to robust human hematopoietic reconstitution in blood, spleen, bone marrow, and liver. Human myeloid cell frequencies, specifically, myeloid dendritic cells, were elevated in the bone marrow of humanized NSG-SGM3 mice compared with nontransgenic NSG recipients. Most significant, however, was the increase in the CD4(+)FoxP3(+) regulatory T-cell population in all compartments analyzed. These CD4(+)FoxP3(+) regulatory T cells were functional, as evidenced by their ability to suppress T-cell proliferation. In conclusion, humanized NSG-SGM3 mice might serve as a useful model to study human regulatory T-cell development in vivo, but this unexpected lineage skewing also highlights the importance of adequate spatiotemporal expression of human cytokines for future xenorecipient strain development.
Project description:CD8(+)/TCR(-) facilitating cells (FCs) in mouse bone marrow (BM) significantly enhance engraftment of hematopoietic stem/progenitor cells (HSPCs). Human FC phenotype and mechanism of action remain to be defined. We report, for the first time, the phenotypic characterization of human FCs and correlation of phenotype with function. Approximately half of human FCs are CD8(+)/TCR(-)/CD56 negative (CD56(neg)); the remainder are CD8(+)/TCR(-)/CD56 bright (CD56(bright)). The CD56(neg) FC subpopulation significantly promotes homing of HSPCs to BM in nonobese diabetic/severe combined immunodeficiency/IL-2 receptor γ-chain knockout mouse recipients and enhances hematopoietic colony formation in vitro. The CD56(neg) FC subpopulation promotes rapid reconstitution of donor HSPCs without graft-versus-host disease (GVHD); recipients of CD56(bright) FCs plus HSPCs exhibit low donor chimerism early after transplantation, but the level of chimerism significantly increases with time. Recipients of HSPCs plus CD56(neg) or CD56(bright) FCs showed durable donor chimerism at significantly higher levels in BM. The majority of both FC subpopulations express CXCR4. Coculture of CD56(bright) FCs with HSPCs upregulates cathelicidin and β-defensin 2, factors that prime responsiveness of HSPCs to stromal cell-derived factor 1. Both FC subpopulations significantly upregulated mRNA expression of the HSPC growth factors and Flt3 ligand. These results indicate that human FCs exert a direct effect on HSPCs to enhance engraftment. Human FCs offer a potential regulatory cell-based therapy for enhancement of engraftment and prevention of GVHD.
Project description:IntroductionCrohn's disease (CD) is characterized by pronounced intestinal fibrosis and severe mucosal damage and conventional animal models are limited to reflect these pathological manifestations. The aim of this study was to examine whether the combination of patient immune-profiling and preclinical studies in a mouse model based on NOD/scid IL-2Rγnull (NSG) reconstituted with peripheral blood mononuclear cells (PBMC) from CD patients has the capacity to harmonize ex vivo human and in vivo animal studies.MethodsImmunological profiles of CD (n = 24) and ulcerative colitis (UC) patients (n = 47) were established by flow cytometry of subgroups of immune cells and subjected to hierarchical cluster and estimation graphics analyses. Pathological phenotypes of NSG mice, which were reconstituted with PBMC from CD, UC, and non-IBD donors (NSG-CD, NSG-UC, and NSG-non-IBD) were compared. Readouts were the clinical, colon, and histological scores; subtypes of immune cells from spleen and colon; and levels of inflammatory markers, such as c-reactive protein (CRP), monocyte chemotactic protein (MCP)-3, transforming growth factor-beta (TGFß), and hepatocyte growth factor (HGF). Fibrocytes were identified by immunohistochemistry in colonic sections.ResultsCD patients were significantly clustered in a group characterized by increased levels of TH1, TH2 cells, and decreased levels of CD14+ CD163+ monocytes (p = .003). In contrast to NSG-UC mice, NSG-CD mice exhibited an immune-remodeling phenotype characterized by enhanced collagen deposition, elevated levels of CD14+ CD163+ monocytes, HGF, and TGFß. This phenotype was further corroborated by the presence of human fibrocytes as components of fibrotic areas.ConclusionThe NSG-CD model partially reflects the human disease and allows for studying the development of fibrosis.
Project description:Regulatory T cells are essential to maintain immune homeostasis and prevent autoimmunity. Therapy with in vitro expanded human nT(Regs) is being tested to prevent graft versus host disease, which is a major cause for morbidity and mortality associated with hematopoietic stem cell transplantation. Their usefulness in therapy will depend on their capacity to survive, migrate appropriately and retain suppressive activity when introduced into a transplant recipient. The lack of a suitable animal model for studying the in vivo reconstitutive capability of human nT(Regs) is a major impediment for investigating the behavior of adoptively transferred nT(Regs)in vivo. We show that injection of a plasmid encoding human IL-2 is necessary and sufficient for long term engraftment of in vitro expanded nT(Regs) in NOD-SCID IL2rγc(null) mice. We also demonstrate that these in vivo reconstituted T(Regs) traffic to different organs of the body and retain suppressive function. Finally, in an IL-2 accelerated GVHD model, we show that these in vivo reconstituted T(Regs) are capable of preventing severe xenogenic response of human PBMCs. Thus, this novel 'hu-T(Reg) mouse' model offers a pre-clinical platform to study the in vivo function and stability of human nT(Regs) and their ability to modulate autoimmune diseases and GVHD.
Project description:Human delta-like 1 (hDlk1) is known to be able to regulate cell fate decisions during hematopoiesis. Mesenchymal stromal cells (MSCs) are known to exhibit potent immunomodulatory roles in a variety of diseases. Herein, we investigated in vivo functions of hDlk1-hMSCs and hDlk1+hMSCs in T cell development and T cell response to viral infection in humanized NOD/SCID/IL-2Rγnull (NSG) mice. Co-injection of hDlk1-hMSC with hCD34+ cord blood (CB) cells into the liver of NSG mice markedly suppressed the development of human T cells. In contrast, co-injection of hDlk1+hMSC with hCD34+ CB cells into the liver of NSG dramatically promoted the development of human T cells. Human T cells developed in humanized NSG mice represent markedly diverse, functionally active, TCR V[Formula: see text] usages, and the restriction to human MHC molecules. Upon challenge with Epstein-Barr virus (EBV), EBV-specific hCD8+ T cells in humanized NSG mice were effectively mounted with phenotypically activated T cells presented as hCD45+hCD3+hCD8+hCD45RO+hHLA-DR+ T cells, suggesting that antigen-specific T cell response was induced in the humanized NSG mice. Taken together, our data suggest that the hDlk1-expressing MSCs can effectively promote the development of human T cells and immune response to exogenous antigen in humanized NSG mice. Thus, the humanized NSG model might have potential advantages for the development of therapeutics targeting infectious diseases in the future.
Project description:Previously, we found that rapid leukemia engraftment (short time to leukemia, TTL(short)) in the NOD/SCID/huALL (non-obese diabetic/severe combined immuno-deficiency/human acute lymphoblastic leukemia) xenograft model is indicative of early patient relapse. As earlier intact apoptosis sensitivity was predictive for good prognosis in patients, we investigated the importance of apoptosis signaling on NOD/SCID/huALL engraftment. Intact apoptosome function as reflected by cytochrome c-related activation of caspase-3 (CRAC-positivity) was strongly associated with prolonged NOD/SCID engraftment (long time to leukemia, TTL(long)) of primary leukemia cells, good treatment response and superior patient survival. Conversely, deficient apoptosome function (CRAC-negativity) was associated with rapid engraftment (TTL(short)) and early relapse. Moreover, an intact apoptosis signaling was associated with high transcript and protein levels of the pro-apoptotic death-associated protein kinase1 (DAPK1). Our data strongly emphasize the impact of intrinsic apoptosis sensitivity of ALL cells on the engraftment phenotype in the NOD/SCID/huALL model, and most importantly also on patient outcome.
Project description:Combining natural killer (NK) cell adoptive transfer with tumor-sensitizing chemotherapy is an attractive approach against recurrent ovarian cancer (OC), as OC is sensitive to NK cell-mediated immunity. Previously, we showed that CD34+ hematopoietic progenitor cell (HPC)-derived NK cells can kill OC cells in vitro and inhibit OC tumor growth in mice. Here, we investigated the potential of HPC-NK cell therapy combined with chemotherapeutic gemcitabine (used in recurrent OC patients) against OC. We examined the phenotypical, functional, and cytotoxic effects of gemcitabine on HPC-NK cells and/or OC cells in vitro and in OC-bearing mice. To this end, we treated OC cells and/or HPC-NK cells with or without gemcitabine and analyzed the phenotype, cytokine production, and anti-tumor reactivity. We found that gemcitabine did not affect the phenotype and functionality of HPC-NK cells, while on OC cells expression of NK cell activating ligands and death receptors was upregulated. Although gemcitabine pre-treatment of OC cells did not improve the functionality of HPC-NK cells, importantly, HPC-NK cells and gemcitabine additively killed OC cells in vitro. Similarly, combined HPC-NK cell and gemcitabine treatment additively decreased tumor growth in OC-bearing mice. Collectively, our results indicate that combination therapy of HPC-NK cells and gemcitabine results in augmented OC killing in vitro and in vivo. This provides a rationale for exploring this therapeutic strategy in patients with recurrent OC.