Guoliang Yan

Arsenic trioxide is a novel agent for combination therapy to prolong heart allograft survival in allo-primed T cells transferred mice.

Alloreactive memory T cells are major barriers to transplantation acceptance due to their capacity to accelerate rejection. Here, we investigated the effects of combined treatment with arsenic trioxide (As(2)O(3)) and blocking monoclonal antibodies (mAb) against CD154 and LFA-1 (anti-CD154/LFA-1) on graft survival as well as changes in pathology and immunological responses in mice with adoptively transferred allo-primed T cells. The mean survival time (MST) for the cardiac allografts in recipient mice receiving the combination of As(2)O(3) and anti-CD154/LFA-1 was significantly longer (>113.7days) compared to those receiving anti-CD154/LFA-1 (23.2days), As(2)O(3) (12.5days) alone or no treatment (5.5days). This combined strategy distinctly inhibited lymphocyte infiltration in grafts, proliferation of splenic T cells and the generation of memory T cells in spleens. Moreover, the combined treatment caused the significant down-regulation of IL-2 and IFN-γ accompanied by increased expression of TGF-β and regulatory T cells (Tregs) in spleens, which led to long-term cardiac allograft survival in recipient mice. These results highlight the potential application of As(2)O(3) and its contribution in combination therapy with antibody blockade to delay rejection by memory T cells.

Overexpression of Jagged-1 combined with blockade of CD40 pathway prolongs allograft survival

Dendritic cells (DCs) have the tolerogenic potential to regulate adaptive immunity and induce allografts acceptance. Here we investigated whether blockade of the CD40 pathway could enhance the immune tolerance induced by DC2.4 cells modified to express Jagged‐1 (JAG1‐DC) in heart transplantation. Results showed that JAG1‐DC treatment combined with anti‐CD40L monoclonal antibody (mAb) administration significantly prolonged cardiac allograft survival in mice, with long‐term survival (>110 days) of 50% of the allografts in the recipients. The therapy specifically inhibited the immune response, induced alloantigen‐specific T‐cell hyporesponsiveness, upregulated transforming growth factor‐β synthesis and increased the population of regulatory T cells (Tregs) driven by Jagged‐1‐Notch activation. These results highlight the potential application of gene therapy to induce alloantigen‐specific Tregs effectively by providing the Jagged‐1 stimulation.

Immunogenicity and functional evaluation of iPSC-derived organs for transplantation.

Whether physiologically induced pluripotent stem cell (iPSC)-derived organs are immunogenic and can be used for transplantation is unclear. Here, we generated iPSC-derived skin, islet, and heart representing three germ layers of the body through 4n complementation and evaluated their immunogenicity and therapeutic efficacy. Upon transplantation into recipient mice, iPSC-derived skin successfully survived and repaired local tissue wounds. In diabetic mouse models, explanted iPSC-derived islets effectively produced insulin and lowered blood glucose to basal levels. iPSC-derived heart grafts maintained normal beating for more than 3 months in syngeneic recipients. Importantly, no obvious immune rejection responses against iPSC-derived organs were detected long after transplantation. Our study not only demonstrates the fundamental immunogenicity and function of iPSC derivatives, but also provides preclinical evidence to support the feasibility of using iPSC-derived skin, islet, and heart for therapeutic use.

Inhibition of accelerated rejection mediated by alloreactive CD4(+) memory T cells and prolonged allograft survival by arsenic trioxide

The aim of this study was to evaluate and determine the potential mechanisms of As2O3 in accelerated rejection mediated by alloreactive CD4+ memory T cells. Vascularized heterotopic cardiac transplantation from C57BL/6 mice to nude mice (pre-transferred CD4+ memory T cells) was performed on Day 0, and As2O3 was administered to recipient mice from Day 0 to 10. As a result, As2O3 could reduce the proliferation of allo-primed CD4+ memory T cells in vitro in MLR and the baseline rate of proliferation was restored by the addition of exogenous IL-2. In vivo, compared with the control[+] group, the mean survival time of cardiac allografts in the As2O3 group was prolonged from 5.8 ± 0.7 to 14.2 ± 2.5 days. Five days after transplantation, the relative gene expression of IL-2, IFN-γ and Foxp3 was reduced in the grafts by As2O3 treatment, but the expression of IL-10 and TGF-β was increased. Correspondingly, the proportions of CD4+ T cells, CD4+ memory T cells and regulatory T cells (Tregs), both in recipient spleens and lymph nodes, were lowered. These results indicate the potential of As2O3 as a novel immunosuppressant targeting CD4+ memory T cells.

Human iPSC‐MSC‐Derived Xenografts Modulate Immune Responses by Inhibiting the Cleavage of Caspases

Mesenchymal stem cells (MSCs) negatively modulate immune properties. Induced pluripotent stem cells (iPSCs)‐derived MSCs are alternative source of MSCs. However, the effects of iPSC‐MSCs on T cells phenotypes in vivo remain unclear. We established an iPSC‐MSC‐transplanted host versus graft reaction mouse model using subcapsular kidney injection. Th1, Th2, regulatory T cells (Treg), and Th17 phenotypes and their cytokines were investigated in vivo and in vitro. The role of caspases and the soluble factors involved in the effects of MSCs were examined. We found that iPSC‐MSC grafts led to more cell survival and less infiltration of inflammatory cells in mice. iPSC‐MSC transplantation inhibited T cell proliferation, decreased Th1 and Th2 phenotypes and cytokines, upregulated Th17 and Treg subsets. Moreover, iPSC‐MSCs inhibited the cleavage of caspases 3 and 8 and inhibition of caspases downregulated Th1, Th2 responses and upregulated Th17, Treg responses. Soluble factors were determined using protein array and TGF‐β1/2/3, IL‐10, and MCP‐1 were found to be highly expressed in iPSC‐MSCs. The administration of the soluble factors decreased Th1/2 response, upregulated Treg response and inhibited the cleavage of caspases. Our results demonstrate that iPSC‐MSCs regulate T cell responses as a result of a combined action of the above soluble factors secreted by iPSC‐MSCs. These factors suppress T cell responses by inhibiting the cleavage of caspases. These data provide a novel immunomodulatory mechanism for the underlying iPSC‐MSC‐based immunomodulatory effects on T cell responses. Stem Cells 2017;35:1719–1732

Arsenic trioxide inhibits accelerated allograft rejection mediated by alloreactive CD8(+) memory T cells and prolongs allograft survival time.

CD8(+) memory T (Tm) cells are a significant barrier to transplant tolerance induction in alloantigen-primed recipients, and are insensitive to existing clinical immunosuppressants. Here, we studied the inhibition of CD8(+) Tm cells by arsenic trioxide (As2O3) for the first time. Alloantigen-primed CD8(+) Tm cells were transferred to T cell immunodeficient nude mice. The mice were subjected to heart allotransplantation, and treated with As2O3. The transplant survival time was determined, and the inhibitory effects of As2O3 on CD8(+) Tm cell-mediated immune rejection were assessed through serological studies and inspection of the transplanted heart and lymphoid organs. We found that As2O3 treatment prolonged the mean survival time of the graft and reduced the number of CD8(+) Tm cells in the spleen and lymph nodes. The expression of the genes encoding interleukin (IL)-2, and IFN-γ was reduced, while expression of IL-10 and transforming growth factor-β was increased in the transplant. Our findings show that As2O3 treatment inhibits allograft rejection mediated by alloreactive CD8(+) Tm cells in the mouse heart transplantation model.

Inhibiting accelerated rejection mediated by alloreactive CD4+ memory T cells and prolonging allograft survival by 1α,25-dihydroxyvitamin D3 in nude mice

Donor-reactive memory T cells are major barriers to long-term survival of transplanted organs due to their capacity to accelerate rejection. In this study we investigated the ability of 1α,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] to inhibit accelerated rejection mediated by alloreactive CD4(+) memory T cells and to prolong cardiac allograft survival in an adoptive T cell memory/heart transplant model of nude mice. In vitro, the proliferation of CD4(+) memory T cells was significantly inhibited by 1,25(OH)(2)D(3) and was restored following addition of exogenous IL-2. Compared with the control group, the mean survival time of cardiac allografts in the 1,25(OH)(2)D(3) group was prolonged from 6.5±0.3 to 20.2±0.8 days in vivo. Five days after transplantation, the levels of IL-2 and IFN-γ were reduced in the grafts and the recipient sera by 1,25(OH)(2)D(3) treatment, while that of IL-10 increased. The proportions of CD4(+) memory T cells and CD4(+)Foxp3(+) T cells, both in recipient spleen and lymph nodes, were lowered by 1,25(OH)(2)D(3) treatment when compared with the control group. Our data suggests that 1,25(OH)(2)D(3) inhibits expansion of CD4(+) memory T cells, possibly by inducing clonal anergy and/or clonal deletion, resulting in prolongation of cardiac allograft survival in nude mice. These results may provide a rational basis for exploiting 1,25(OH)(2)D(3) as a novel immunosuppressant targeting CD4(+) memory T cells.

CD44/CD70 blockade and anti-CD154/LFA-1 treatment synergistically suppress accelerated rejection and prolong cardiac allograft survival in mice.

Current treatments that are efficient in controlling effector T cell responses to allografts have limited efficacy on the accelerated rejection mediated by memory T cells. Effective targeting of alloreactive memory T cells may therefore be explored to improve therapeutic approaches towards solving this problem. In this study, we investigated the synergistic effect of CD44/CD70 blockade and anti‐CD154/LFA‐1 treatment on the accelerated rejection mediated by memory T cells. While CD44/CD70 blockade had limited effects on the alloresponses of effector T cells in vivo, it diminished the expansion of both CD4+ and CD8+ memory T cells in recipients adoptively transferred with donor‐sensitized T cells. In combination with anti‐CD154/LFA‐1 treatment, CD44/CD70 blockade significantly prolonged cardiac allograft survival in adoptive transfer recipients. We demonstrated that treatment with the combination of all four antibodies (anti‐CD154/LFA‐1/CD44/CD70) inhibited accelerated rejection by markedly suppressing the alloresponses of effector and memory T cells and reducing the number of graft‐infiltration lymphocytes in adoptive transfer recipients. Meanwhile, CD44/CD70 blockade and anti‐CD154/LFA‐1 treatment synergically enhanced regulatory T cells (Tregs) by increasing the proportion of splenic Tregs and the expression of IL‐10 in these recipients. Our findings contribute to the potential design of therapies for accelerated allograft rejection.

Ectopic Drainage from the Inferior Vena Cava to the Left Atrium Together with a Partial Anomalous Pulmonary Venous Connection

We report a case of a 44-year-old male patient with ectopic drainage from the inferior vena cava to the left atrium accompanied by partial anomalous pulmonary venous drainage. After the patient was hospitalized, his diagnosis was confirmed by Doppler echocardiography and angiography. A pericardial patch was used to divert the blood to the atrium. The surgical procedure was successful, and the patient began a rehabilitation program 8 days later. This type of ectopic drainage pattern is an unusual and infrequent clinical finding. The definitive diagnosis should be made by Doppler ultrasound combined with angiography.

The development of an extra-anatomic tissue-engineered artery with collateral arteries for therapeutic angiogenesis in ischemic hind limb

To develop tissue-engineered arteries (TEAs) with collateral arteries(CAs) in ischemic hind limb goat models(IHLMs). The IHLMs created by removing femoral arteries were divided into non-treated control group(NG); non-catheter group (NCG) in which TEA was anastomosed to external iliac artery(EIA), and surrounded with collagen sponge containing autologous MSCs and VEGF-gelatin microspheres, the distal end of TEA was ligated; catheter group(CG) which received the same procedure as NCG, also received heparin infusion through catheter in EIA. TEA patency was assessed weekly by Ultrasound. The TEA and CAs were assessed by angiography, gross examination, histology and electron microscopy. In CG, TEAs remained patent for 1 month, but became partly occluded 1 week after catheter withdrawn. In NCG, TEAs were occluded 1 week after implantation. Angiography demonstrated that communication between CAs arising from the TEAs and the native vessels was established in both groups. NCG had fewer CAs than CG (P < 0.01). At 40 days, TEAs in CG demonstrated of endothelium formation, smooth muscle cells infiltration and collagen regeneration. The CG had more capillaries and mature vessels in adventia of TEAs than NCG (P < 0.01). CG group also had more vessels around TEAs than NCG (P < 0.01) or NG (P < 0.001).