Conversion of antigen-specific effector/memory T cells into Foxp3-expressing T cells by inhibition of CDK8/19.

A promising way to restrain hazardous immune responses, such as autoimmune disease and allergy, is to convert disease-mediating T cells into immunosuppressive regulatory T (T) cells. Here, we show that chemical inhibition of the cyclin-dependent kinase 8 (CDK8) and CDK19, or knockdown/knockout of the CDK8 or CDK19 gene, is able to induce Foxp3, a key transcription factor controlling T cell function, in antigen-stimulated effector/memory as well as naïve CD4 and CD8 T cells. The induction was associated with STAT5 activation, independent of TGF-β action, and not affected by inflammatory cytokines.

Microarray gene expression profiling of chronic allograft nephropathy in the rat kidney transplant model.

Whole genome gene expression profiles were correlated with renal function and histology in a well-established animal model of chronic allograft nephropathy (CAN). Kidneys of F344 rats were transplanted into LEW recipients treated with a brief dose of FK506 (BFK). Blood and urine samples were collected weekly.

Prevention of allograft rejection by amplification of Foxp3(+)CD4(+)CD25(+) regulatory T cells.

CD4(+)CD25(+) T cells were identified originally as potent suppressors of autoimmunity and were later termed "natural regulatory T cells" or nTreg cells. Subsequently, a transcription factor called forkhead box protein 3 (Foxp3) was identified to be a critical regulator for Treg differentiation and function. Foxp3(+)CD4(+)CD25(+) Treg cells have been increasingly documented to suppress allograft rejection and to mediate allograft tolerance in transplantation.

ECDI-fixed allogeneic splenocytes induce donor-specific tolerance for long-term survival of islet transplants via two distinct mechanisms.

A major challenge for human allogeneic islet transplantation is the development of effective methods to induce donor-specific tolerance to obviate the need for life-long immunosuppression that is toxic to the insulin-producing beta cells and detrimental to the host. We developed an efficient donor-specific tolerance therapy that utilizes infusions of ethylene carbodiimide (ECDI)-treated donor splenic antigen-presenting cells that results in indefinite survival of allogeneic islet grafts in the absence of immunosuppression. Furthermore, we show that induction of tolerance is critically dependent on synergistic effects between an intact programmed death 1 receptor-programmed death ligand 1 signaling pathway and CD4(+)CD25(+)Foxp3(+) regulatory T cells.

Prolonging islet allograft survival using in vivo bioluminescence imaging to guide timing of antilymphocyte serum treatment of rejection.

Background: Bioluminescence imaging (BLI) is a sensitive and noninvasive method for tracking the fate of transplanted islets. The aim of this study was to investigate whether early detection of rejection by BLI can aid in the timing of antilymphocyte serum (ALS) treatment for prolonging islet graft survival.

Methods: Transgenic islets (200 per recipient) expressing the firefly luciferase from FVB/NJ strain (H-2q) mice were transplanted under the kidney capsule of streptozotocin-induced diabetic allogeneic Balb/c strain (H-2q) mice.

Targeting acute allograft rejection by immunotherapy with ex vivo-expanded natural CD4+ CD25+ regulatory T cells.

Background: Natural CD4CD25 regulatory T (Treg) cells have been implicated in suppressing alloreactivity in vitro and in vivo. We hypothesized that immunotherapy using ex vivo-expanded natural Treg could prevent acute allograft rejection in mice.

Methods: Natural CD4+ CD25+ Treg were freshly purified from naive mice via automated magnetic cell sorter and expanded ex vivo by anti-CD3/CD28 monoclonal antibody (mAb)-coated Dynabeads.

Graft-versus-leukemia and graft-versus-host reactions after donor lymphocyte infusion are initiated by host-type antigen-presenting cells and regulated by regulatory T cells in early and long-term chimeras.

Regulatory T (T(reg)) cells and host antigen-presenting cells (APCs) have been implicated in graft-versus-host disease (GVHD) and the graft-versus-leukemia (GVL) effect after donor lymphocyte infusion (DLI), but their relative contributions remain unclear in early versus long-term complete donor or mixed murine allogeneic hematopoietic stem cell (HSC) chimeras. We have previously demonstrated that donor HSC-derived Thy1(+) T(reg) cells, consisting primarily of CD4(+)CD25(+) cells, play an important role in the suppression of graft-versus-host (GVH) reactivity when DLI is given to complete donor chimeras 28 days after HSC transplantation. Data presented here demonstrate that protection against GVHD exerted by Thy1(+) T(reg) cells is less evident with time and eventually is not required in long-term complete donor chimeras because of an absence of host-type APCs to activate alloreactive T cells.

Tracking ex vivo-expanded CD4+CD25+ and CD8+CD25+ regulatory T cells after infusion to prevent donor lymphocyte infusion-induced lethal acute graft-versus-host disease.

Donor bone marrow (BM)-derived CD4+ CD25+ regulatory T cells, maturing in the host thymus, are critical in inhibiting graft-versus-host disease (GVHD) after donor lymphocyte infusion (DLI) in murine BM chimeras. Data presented here demonstrate that fresh CD25+ cells isolated from donor-type mice can be expanded ex vivo by a variety of methods. Ex vivo-expanded CD4+ CD25+ and CD8+ CD25+ cells were potent suppressors of donor response to host alloantigens in mixed lymphocyte reaction assays.

Pathogenesis of autoimmunity after xenogeneic thymus transplantation.

Thymus transplantation is a promising strategy to induce xenotolerance, but may also induce an autoimmune syndrome (AIS). The pathogenesis of this AIS was explored using nude rats as recipients. Thymus grafts consisted of fetal hamster thymic tissue with or without mixing with fetal rat tissue such as thymus, thyroid, salivary gland, and heart.

Upregulation of endogenous heparin-binding EGF-like growth factor (HB-EGF) expression after intestinal ischemia/reperfusion injury.

Expression of endogenous heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF), a proven intestinal cytoprotective molecule, was examined in intestinal epithelial cells (IEC) in vitro, and in intestine undergoing ischemia/reperfusion (I/R) injury in vivo. In vitro, cells were exposed to anoxia for 90 min followed by reoxygenation for 1-3 h (A/R). In vivo, total midgut I/R injury was produced in rats by occlusion of the superior mesenteric artery for 30 or 90 min followed by reperfusion for 4 h.

Heparin-binding EGF-like growth factor downregulates expression of adhesion molecules and infiltration of inflammatory cells after intestinal ischemia/reperfusion injury.

Background/purpose: This study examined whether heparin-binding epidermal growth factor (EGF) like growth factor (HB-EGF), a proven intestinal cytoprotective molecule, exerts its protective effects through modulation of adhesion molecule expression and inflammatory cell infiltration, important pathogenic mediators of ischemia/reperfusion (I/R) injury.

Methods: Total midgut I/R injury in rats was achieved by occlusion of the superior mesenteric artery for 90 minutes followed by reperfusion. Rats were treated intraluminally with 600 microg/kg HB-EGF or with PBS 45 minutes after the onset of ischemia.

Heparin-binding EGF-like growth factor preserves crypt cell proliferation and decreases bacterial translocation after intestinal ischemia/reperfusion injury.

Background/purpose: Heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF), a known mitogenic, chemotactic, and cytoprotective growth factor for epithelial cells, was examined to see whether it could protect intestinal barrier function and decrease bacterial translocation (BT) after ischemia/reperfusion (I/R) injury.

Methods: In vitro, tight junctional integrity of intestinal epithelial cells (IEC-6) cells was evaluated by measuring transepithelial electric resistance (TEER), and monolayer permeability was evaluated by translocation of Escherichia coli C25. In vivo, crypt cell proliferation was assessed by 5-bromodeoxyuridine incorporation with calculation of a proliferative index (PI), and BT was evaluated by culture of mesenteric lymph nodes.