10 results on '"Yi, Shounan"'
Search Results
2. Human mesenchymal-stem-cells-derived exosomes are important in enhancing porcine islet resistance to hypoxia.
- Author
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Nie W, Ma X, Yang C, Chen Z, Rong P, Wu M, Jiang J, Tan M, Yi S, and Wang W
- Subjects
- Animals, Cells, Cultured, Culture Media, Conditioned metabolism, Disease Models, Animal, Humans, Islets of Langerhans Transplantation methods, Mesenchymal Stem Cell Transplantation methods, Swine, Transplantation, Heterologous methods, Exosomes immunology, Hypoxia, Islets of Langerhans cytology, Mesenchymal Stem Cells cytology
- Abstract
Background: Hypoxia-induced damage is one of the key factors associated with islet graft dysfunction. Mesenchymal stem cells (MSCs) could be used to enhance the therapeutic effect of islet transplantation due to their paracrine potential such as exosomes. In this study, we investigated whether exosomes from human umbilical cord-derived MSC-conditioned medium (hu-MSC-CM) could increase the survival and function of neonatal porcine islet cell clusters (NICCs) exposed to hypoxia., Methods: Neonatal porcine islet cell clusters were cultured with hu-MSC-CM, with or without exosomes, and native medium RPMI-1640 (Control) under hypoxic conditions (1% O
2 ). The effects of exosomes on NICCs viability and function in vitro were examined by FACS, the Loops system, and the Extracellular Flux assay, respectively., Results: Compared with NICCs cultured in RPMI-1640 medium and hu-MSC-CM without exosomes, the survival ratio, viability, and function increased in NICCs cultured in hu-MSC-CM with exosomes., Conclusions: This study found that hu-MSC-CM could protect NICCs from hypoxia-induced dysfunction, and exosomes played an important role in hypoxic resistance, suggesting a potential strategy to improve islet transplantation outcomes., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)- Published
- 2018
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3. Culturing with modified EGM2 medium enhances porcine neonatal islet-like cell clusters resistance to apoptosis in islet xenotransplantation.
- Author
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Ma X, Yang C, Zhang J, Wang J, Li W, Xu C, Rong P, Ye B, Wu M, Jiang J, Yi S, and Wang W
- Subjects
- Animals, Animals, Newborn, Cells, Cultured, Diabetes Mellitus immunology, Glucose metabolism, Humans, Insulin metabolism, Islets of Langerhans Transplantation methods, Apoptosis immunology, Heterografts immunology, Islets of Langerhans cytology, Transplantation, Heterologous methods
- Abstract
Background: Neonatal pig islet-like cell clusters (NICC) are an attractive source of insulin-producing tissue for potential transplantation treatment of type 1 diabetic patients. However, a considerable loss of NICC after their transplantation due to apoptosis resulted from islet isolation and instant blood-mediated inflammatory reaction remains to be overcome., Methods: EGM2 medium depleted with hydrocortisone and supplemented with 50 mmol/L isobutylmethylxanthine, 10 mmol/L nicotinamide, and 10 mmol/L glucose was used to culture NICC at day 1, the day after isolation and changed every other day. NICC cultured with EGM2 or control Ham's F-10 medium were collected at day 7 of culture for the following assays. The viability of NICC was evaluated by AO/EB staining and FACS. Static assay and oxygen consumption rate analysis were performed to assess the function of NICC. Insulin and glucagon gene expression were measured by real-time PCR. Tubing loops model and TUNEL assay were performed to confirm the apoptosis-resistant ability of NICC cultured with modified EGM2 medium. Serum starvation and hypoxia treatment were used to test the tolerant capability of NICC in the microenvironment of hypoxia/nutrient deficiency in vitro. The molecules involved in apoptosis pathways in NICC were analyzed by Western blotting., Results: Compared with Ham's F-10 medium, culturing NICC with EGM2 medium led to increased number and viability of NICC with higher stimulation index, upregulated gene expression of both insulin and glucagon, and enhanced mitochondria function. Furthermore, fewer modified EGM2 medium cultured NICC were found under apoptosis when evaluated in an in vitro tubing loop model of IBMIR. Moreover, EGM2 medium cultured NICC demonstrated much less apoptotic cells under either serum starvation or hypoxia condition than their Ham's F-10 medium cultured counterparts. The enhanced capability of EGM2 cultured NICC to resist apoptosis was associated with their elevated protein levels of anti-apoptotic Bcl-2 family member Mcl-1., Conclusion: Culturing NICC with EGM2 provides a simple and effective approach not only to increase NICC yield, viability, and maturation but also to enhance their resistance to apoptosis to preserve the initial graft mass for successful islet xenotransplantation., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
- Published
- 2018
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4. Ex vivo-expanded baboon CD39 + regulatory T cells prevent rejection of porcine islet xenografts in NOD-SCID IL-2rγ -/- mice reconstituted with baboon peripheral blood mononuclear cells.
- Author
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Huang D, Wang Y, Hawthorne WJ, Hu M, Hawkes J, Burns H, Davies S, Gao F, Chew YV, Yi S, and O'Connell PJ
- Subjects
- Animals, Antigens, CD immunology, Apyrase immunology, Graft Rejection immunology, Immunosuppressive Agents pharmacology, Interleukin-2 genetics, Islets of Langerhans immunology, Mice, Inbred NOD, Mice, SCID, Papio, Swine, Transplantation, Heterologous methods, Heterografts immunology, Islets of Langerhans Transplantation methods, Leukocytes, Mononuclear immunology, T-Lymphocytes, Regulatory immunology
- Abstract
Background: A high immunosuppressive burden is required for long-term islet xenograft survival in non-human primates even using genetically modified donor pigs., Aims: We aimed to investigate the capacity of baboon regulatory T cells (Treg) to suppress islet xenograft rejection, thereby developing a potential immunoregulatory or tolerance therapy that could be evaluated in NHP models of xenotransplantation., Materials & Methods: Baboon Treg expanded with stimulation by porcine peripheral blood mononuclear cells (PBMC) were characterized by cell phenotyping and suppressive activity assays in vitro. Their function in vivo was evaluated in neonatal porcine islet cell clusters (NICC) transplanted NOD-SCID IL-2rγ-/- (NSG) mice receiving baboon PBMC alone or with expanded autologous Treg., Results: The majority of expanded Treg coexpressed Foxp3 and CD39 and were highly suppressive of the baboon anti-pig xenogeneic T cell response in vitro. Reconstitution of mice with baboon PBMC alone resulted in NICC xenograft rejection within 35 days. Cotransfer with baboon PBMC and Treg prolonged islet xenograft survival beyond 100 days, correlating with Treg engraftment, intragraft CD39 and Foxp3 gene expression, and reduced graft infiltrating effector T cells and reduced interferon-γ production., Discussion & Conclusion: Our data supports the capacity of ex vivo expanded CD39+ baboon Treg to suppress islet xenograft rejection in primatized mice, suggesting it has potential as an adjunctive immunotherapy in preclinical NHP models of xenotransplantation., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
- Published
- 2017
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5. Human regulatory macrophages are potent in suppression of the xenoimmune response via indoleamine-2,3-dioxygenase-involved mechanism(s).
- Author
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Guo F, Hu M, Huang D, Zhao Y, Heng B, Guillemin G, Lim CK, Hawthorne WJ, and Yi S
- Subjects
- Animals, Cell Proliferation drug effects, Cells, Cultured, Humans, Immunosuppression Therapy, Monocytes immunology, Swine, T-Lymphocytes immunology, Transplantation, Heterologous methods, Indoleamine-Pyrrole 2,3,-Dioxygenase metabolism, Leukocytes, Mononuclear immunology, Macrophages immunology
- Abstract
Background: For xenotransplantation to truly succeed, we must develop immunomodulatory strategies to suppress the xenoimmune response but by minimizing immunosuppression over the long term. Regulatory macrophages (Mreg) have been shown to suppress polyclonal T-cell proliferation in vitro and prolong allograft survival in vivo. However, the question of whether they are capable of suppressing xenoimmune responses remains unknown. This study assessed the potential of human Mreg to be used as an effective immunomodulatory method in xenotransplantation., Methods: CD14+ monocytes selected from human peripheral blood mononuclear cells (PBMC) were cultured with macrophage colony-stimulating factor (M-CSF) for 7 days with IFN-γ added at day 6 for Mreg induction. Mreg phenotyping was performed by flow cytometric analysis, and the in vitro suppressive function was assessed by mixed lymphocyte reaction (MLR) using irradiated pig PBMC as the xenogeneic stimulator cells, human PBMC as responder cells, and autologous Mreg as suppressor cells. To assess mRNA expression of Mreg functional molecules indoleamine-2,3-dioxygenase (IDO), IL-10, inducible nitric oxide synthase (iNOS) and TGF-β were measured by real-time PCR. Supernatants were collected from the MLR cultures for IDO activity assay by high-performance liquid chromatography (HPLC). The effects of the IDO inhibitor 1-D/L-methyl-tryptophan (1-MT), iNOS inhibitor N
G -monomethyl-l-arginine (L-NMMA), and anti-IFN-γ or anti-TGF-β monoclonal antibody (mAb) treatment on Mreg suppressive capacity were tested from the supernatants of the MLR assays., Results: We demonstrated that induced Mreg with a phenotype of CD14low CD16-/low CD80low CD83-/low CD86+/hi HLA-DR+/hi were capable of suppressing proliferating human PBMC, CD4+, and CD8+ T cells, even at a higher responder:Mreg ratio of 32:1 in a pig-human xenogeneic MLR. The strong suppressive potency of Mreg was further correlated with their upregulated IDO expression and activity. The IDO upregulation of Mreg was associated with an increased production of IFN-γ, an IDO stimulator, by xenoreactive responder cells in the xenogeneic MLR. While no effect on Mreg suppressive potency was detected by addition of the iNOS inhibitor L-NMMA or anti-TGF-β mAb into the MLR assays, inhibition of IDO activity by neutralizing IFN-γ or by IDO inhibitor 1-MT substantially impaired the capacity of Mreg to suppress the xenogeneic response, indicating the importance of upregulated IDO activity in Mreg-mediated suppression of the xenogeneic response in vitro., Conclusion: This study demonstrates that human Mreg are capable of suppressing the xenoimmune response in vitro via IDO-involved mechanism(s), suggesting their potential role as an effective immunomodulatory tool in xenotransplantation., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)- Published
- 2017
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6. Hepatic artery vs. portal vein infusion of microbeads: a large animal pre-clinical model evaluating the intrahepatic capacity for cell infusion and imaging.
- Author
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Wang W, Liu S, Zheng W, Gao F, Hawthorne WJ, and Yi S
- Subjects
- Alanine Transaminase metabolism, Alginates chemistry, Alginates metabolism, Animals, Biocompatible Materials chemistry, Biocompatible Materials metabolism, Diabetes Mellitus, Type 1 surgery, Dogs, Hypertension, Portal chemically induced, Infusions, Intravenous adverse effects, Islets of Langerhans Transplantation adverse effects, Liver blood supply, Liver cytology, Liver metabolism, Liver pathology, Male, Polylysine analogs & derivatives, Polylysine chemistry, Polylysine metabolism, Thrombosis chemically induced, Transplantation, Heterologous methods, Hemodynamics, Hepatic Artery physiology, Infusions, Intravenous methods, Islets of Langerhans Transplantation methods, Microspheres, Models, Animal, Portal Vein physiology
- Abstract
Background: Islet xeno-transplantation via the portal vein has been proposed as an alternative of islet allo-transplantation for treatment of type 1 diabetes. However, the precise hepatic capacity has not been addressed., Methods: We mimicked cell transplantation by infusion of dogs with alginate/poly-1-lysine/alginate (APA) microbeads via either the portal vein (PV) or hepatic artery (HA). The maximal adaptable capacity for infused microbeads was evaluated by examination of vasculature, microvasculature, hepatic hemodynamics, portal vein, and hepatic artery pressures and liver function in the microbead recipient dogs., Results: PV but not HA dogs demonstrated elevated portal pressure during the infusion procedure in a dose-dependent manner. Four out of twelve PV dogs infused with 32,000 microbeads/kg developed acute liver infarction within 24 h after infusion with four of the remaining eight animals developing portal venous thrombosis within 24 h following infusion. All PV animals demonstrated abnormal alanine aminotransferase (ALT) values, and the extent and duration of increased ALT levels correlated with the increase in the number of microbeads infused. In contrast, HA animals infused with as many as 32,000 microbeads/kg had neither portal thrombosis nor abnormal liver function., Conclusions: The capacity for intrahepatic cell infusion is finite and the intrahepatic artery may have a less hemodynamic interference impact on transplantation of cells into the liver when a larger volume of cells is required to achieve curable outcomes in both allo- and xeno-transplantation.
- Published
- 2010
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7. Foxp3 regulates human natural CD4+CD25+ regulatory T-cell-mediated suppression of xenogeneic response.
- Author
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Sun L, Yi S, and O'Connell PJ
- Subjects
- Animals, Cytokines immunology, Forkhead Transcription Factors genetics, Gene Knockdown Techniques, Humans, Lymphocyte Subsets immunology, RNA, Small Interfering genetics, RNA, Small Interfering metabolism, Swine, CD4-Positive T-Lymphocytes immunology, Forkhead Transcription Factors physiology, Interleukin-2 Receptor alpha Subunit immunology, T-Lymphocytes, Regulatory immunology, Transplantation, Heterologous immunology
- Abstract
Backgrounds: Cellular rejection of xenografts is predominantly mediated by CD4+ T cells. Foxp3 expressing human naturally occurring CD4+CD25+ regulatory T cells (nTregs) have been shown to suppress pathological and physiological immune responses, including the CD4+ T-cell-mediated anti-pig xenogeneic response in vitro. Although Foxp3 is required for nTreg development and their function, the precise role of Foxp3 in regulating Treg suppressive function in xenoimmune response remains to be identified., Methods: In vitro expanded human nTregs were transfected with fluorescein isothiocyanate -conjugated Foxp3 small interfering RNA (siRNA) by Lipofectamine 2000. Transfected nTregs were sorted by fluorescence-activated cell sorting, and then analyzed for Foxp3 gene and protein expression as well as their phenotypic characteristics. Human CD4+CD25- T cells were stimulated with xenogeneic pig peripheral blood mononuclear cell in the presence or absence of nTregs in a coculture or transwell system for evaluation of nTreg suppressive activity. The production of effector cytokines by xenoreactive CD4+CD25- T cells as well as suppressive cytokine by nTregs in their cocultures was examined by ELISA., Results: The siRNA-mediated Foxp3 knockdown resulted in impaired nTreg anergic state, downregulated expression of nTreg function associated molecules, and reduced production of suppressive cytokines by nTregs, which together leading to impaired nTreg-mediated suppression of CD4+CD25- T-cell proliferation and their effector cytokine production in response to xenogeneic stimulation., Conclusions: This study demonstrates that Foxp3 expression is required for human nTregs to maintain their suppressive function in the xenoimmune response.
- Published
- 2010
- Full Text
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8. Selective rejection of porcine islet xenografts by macrophages.
- Author
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Fu Y, Lu X, Yi S, Wu J, O'Hara JM, Hawthorne WJ, Hucker K, and O'Connell PJ
- Subjects
- Animals, Blood Glucose immunology, Female, Graft Rejection blood, Graft Rejection pathology, Islets of Langerhans Transplantation pathology, Macrophage Activation immunology, Male, Mice, Transplantation, Homologous immunology, Graft Rejection immunology, Islets of Langerhans Transplantation adverse effects, Islets of Langerhans Transplantation immunology, Macrophages immunology, Swine immunology, Transplantation, Heterologous immunology
- Abstract
Background: Our previous study has shown that porcine antigen-primed and CD4+ T cell-activated macrophages are capable of recognition and rejection of porcine xenografts after adoptive transfer. However, whether this is an absolute xenograft specific rejection remains to be confirmed., Methods: Mouse islet allografts and neonatal porcine islet cell cluster (NICC) xenografts were admixed and transplanted under the left kidney capsule, and NICC xenografts alone were transplanted under the right kidney capsule of strepotozotocin-induced diabetic NOD-SCID mice. After achievement of normoglycemia, the NOD-SCID recipients were transferred with macrophages purified from NICC transplant NOD-SCID mice reconstituted with CD4+ T cells. Five weeks after macrophage transfer the left kidney with the admixed grafts were removed. Graft survival and function following macrophage transfer was assessed by blood glucose measurement and immunohistochemistry., Results and Conclusions: Adoptive transfer with activated macrophages did not affect the normalized blood glucose levels in NOD-SCID recipients of admixed grafts until left nephrectomy 5 weeks post-macrophage transfer. Insulin-positive and porcine C-peptide-negative mouse islets were detected in the admixed grafts. The surviving mouse islets in the admixed grafts were surrounded but not infiltrated by macrophages. The nephrectomized recipients demonstrated sustained hyperglycemia and completely destroyed NICC xenografts in their remaining right kidneys 8 weeks after macrophage transfer. Taken together, these data provide direct evidence of porcine islet xenograft specific rejection by activated macrophages.
- Published
- 2008
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9. Chemokine and toll-like receptor signaling in macrophage mediated islet xenograft rejection.
- Author
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Chandra AP, Ouyang L, Yi S, Wong JK, Ha H, Walters SN, Patel AT, Stokes R, Jardine M, Hawthorne WJ, and O'Connell PJ
- Subjects
- Animals, CD4-Positive T-Lymphocytes immunology, Cell Movement, Chemokines immunology, Female, Gene Expression, Graft Rejection metabolism, Islets of Langerhans Transplantation adverse effects, Islets of Langerhans Transplantation pathology, Macrophages cytology, Macrophages metabolism, Mice, Receptors, CCR2, Receptors, CCR5 genetics, Receptors, CCR5 immunology, Receptors, Chemokine genetics, Receptors, Chemokine immunology, Skin immunology, Skin metabolism, Swine, Toll-Like Receptors genetics, Up-Regulation, Chemokines metabolism, Graft Rejection immunology, Islets of Langerhans Transplantation immunology, Macrophages immunology, Signal Transduction immunology, Toll-Like Receptors metabolism, Transplantation, Heterologous immunology
- Abstract
Background: Adoptive transfer of antigen-primed T-cell-activated macrophages into NOD-SCID mice within 14 days of foetal porcine pancreatic fragment (FPP) or foetal porcine skin (FPS) transplantation had been shown to cause xenograft rejection. In the present study, it was proposed that signaling between the graft and macrophages promoted specific graft recognition and destruction in this setting., Methods: Exogenous macrophages isolated from rejecting FPP xenografts were transferred to NOD-SCID FPP recipients and tracked by Ly5.1 surface antigen or via CSFE staining. Monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1alpha (MIP-1alpha), macrophage inflammatory protein-1beta (MIP-1beta), regulated upon activation, normal T-cell expressed and secreted (RANTES), chemokine (C-C motif) receptor 2 (CCR2), chemokine (C-C motif) receptor 5 (CCR5), toll-like receptors (TLRs) (1-9) and gene expression in transplanted FPP xenografts was evaluated by real-time polymerase chain reaction. Gene expression of CCR2, CCR5 and TLRs was also analyzed in pooled samples of activated and non-activated macrophages., Results: Exogenous macrophages were shown to track to and reject recently transplanted but not established FPP xenografts. Gene expression for MCP-1, RANTES, MIP-1alpha and MIP-1beta was at least 3-fold greater in recently transplanted compared with established xenografts (P < 0.05), and CCR2 and CCR5 gene expression was 10-fold greater in activated compared non-activated macrophages, suggesting that graft-mediated pro-inflammatory signals were important for macrophage recruitment. Specific graft recognition by macrophages may involve TLR signaling as macrophages exposed to porcine islets had higher levels of TLR gene expression compared with those exposed to allografts regardless of the level of activation., Conclusion: Xenografts provide additional activation signals to macrophages that are not seen following allotransplantation. This study identifies chemokines and TLR as important signals in macrophage-mediated recognition and rejection of islet xenografts.
- Published
- 2007
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10. IFN-gamma but not IL-4 is important for mouse CD4+ T cell-mediated macrophage activation following their exposure to pig cells in vitro.
- Author
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Yi S and O'Connell PJ
- Subjects
- Animals, Antibody Formation, Cell Membrane immunology, Cells, Cultured, Cytokines analysis, DNA Primers, Fetal Tissue Transplantation immunology, Flow Cytometry, Macrophage Activation drug effects, Male, Mice, Mice, Inbred C57BL, Reverse Transcriptase Polymerase Chain Reaction, Swine, CD4-Positive T-Lymphocytes immunology, Interferon-gamma genetics, Interferon-gamma pharmacology, Interleukin-4 genetics, Macrophage Activation immunology, Transplantation, Heterologous immunology
- Abstract
In order to investigate the mechanism by which CD4+ T cells and macrophages interact in the xenogeneic immune response, murine CD4+ T cells and macrophages were used as responder cells in culture with irradiated fetal pig spleen cells (FPSC) as pig xenogeneic stimulators. In this in vitro model, murine CD4+ T cells and macrophages were cultured individually, or together with FPSC. In addition, mouse CD4+ T cells were also cultured with autologous macrophages which were previously stimulated by FPSC. The cultured murine cells were analyzed for expression of CD4+ T cell and macrophage activation markers (cell surface markers and cytokines) as well as cytokine production. CD4+ T cells and macrophages cultured alone or together without FPSC showed unchanged low levels of expression of activation markers. Coculture of macrophages with FPSC and in the absence of CD4+ T cells induced increased expression levels of all the activation markers examined except B7.2 and ICAM-1. Addition of CD4+ T cells to the coculture further enhanced this up-regulation. Coculture of CD4+ T cells with FPSC-stimulated macrophages, but not naive macrophages, or FPSC alone, resulted in significantly increased numbers of CD4+ T cells coexpressing their activation markers, especially IFN-gamma and CD40L, and this expression was enhanced further by including FPSC in the coculture. The activation of both CD4+ T cells and macrophages in their coculture with FPSC was suppressed by neutralizing IFN-gamma but not IL-4. Our results demonstrated that interaction of CD4+ T cells and autologous macrophages was required for their optimal activation in response to pig xenogeneic stimulation. The mechanisms involved included cell-cell and/or cytokine interactions, and in particular IFN-gamma mediated communication was involved. Macrophages activated by pig cells in the absence of CD4+ T cells were able to activate naive CD4+ T cells, thus providing an important communication pathway between innate immune activation and a T cell mediated response in xenograft rejection.
- Published
- 2002
- Full Text
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