Lin Xie

Amelioration of experimental autoimmune encephalomyelitis by curcumin treatment through inhibition of IL-17 production

Experimental autoimmune encephalomylitis (EAE), an animal mode of multiple sclerosis (MS), was previously considered that be mediated by Th1 cells. However, a number of recent studies provided strong evidence that T helper cells that produce IL-17 play a dominant role in the pathogenesis of EAE. Curcumin (1,7-Bis 94-hydroxy-3-methoxyphenyl)-1,6 heptadiene-3, 5-di-one) is a naturally occurring polyphenolic phytochemical isolated from the rhizome of the medicinal plant Curcuma longa. It has been strongly implicated as an anti-inflammatory agent, but the precise mechanisms of its action are largely unknown. In the present study, we have investigated the efficacy and mechanism of curcumin against EAE. The treatment of Lewis rats with curcumin significantly reduced the clinical severity of EAE, and had a dramatic reduction in the number of inflammatory cells infiltration in the spinal cord. The proliferation of the MBP-reaction lymphocyte also was reduced in a curcumin dose-dependent manner. Furthermore, the mRNA expression of the cytokine profiles was assessed by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), revealing the dramatic decrease of IL-17, TGF-beta, IL-6, IL-21, STAT3, and RORgammat expression in curcumin-treated groups and STAT3-phosphorylation also was inhibited. These findings indicated that curcumin amelioration EAE was, to a large extent, due to inhibit differentiation and development of Th17 cells depends on down-regulating expression of IL-6, IL-21, RORgammat signaling and inhibition STAT3-phosphorylation, suggests it is useful in the treatment of MS and other Th17 cell-mediated inflammatory diseases.

PD-1/B7-H1 interaction contribute to the spontaneous acceptance of mouse liver allograft.

The programmed death‐1 (PD‐1)/B7‐H1 pathway acts as an important negative regulator of immune responses. We herein investigated the role of the PD‐1/B7‐H1 pathway in establishing an immunological spontaneous tolerance status in mouse liver allografting. B7‐H1 is highly expressed on the donor‐derived tissue cells and it is also associated with the apoptosis of infiltrating T cells in the allografts. Strikingly, a blockade of the PD‐1/B7‐H1 pathway via anti‐B7‐H1mAb or using B7‐H1 knockout mice as a donor led to severe cell infiltration as well as hemorrhaging and necrosis, thus resulting in mortality within 12 days. Furthermore, the expression of the FasL, perforin, granzyme B, iNOS and OPN mRNA in the liver allografts increased in the antibody‐treated group in comparison to the controls. Taken together, these data revealed that the B7‐H1 upregulation on the tissue cells of liver allografts thus plays an important role in the apoptosis of infiltrating cells, which might play a critical role of the induction of the spontaneous tolerance after hepatic transplantation in mice.

Curcumin has bright prospects for the treatment of multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS). It is associated with a variety of pathophysiological features, including breakdown of the blood-brain barrier (BBB), autoimmune attack, injury of axons and myelin sheaths. Th17 cells are considered as a key immunological player for the pathophysiological process of MS. Neuroprotective approaches work best prior to the initiation of damage, suggesting that some safe and effective prophylaxis would be highly desirable. Curcumin, a dietary spice from turmeric, has outstanding anti-inflammation and neuroprotective effects. Herein, we review key features of curcumin involved biology, pharmacology, and medicinal chemistry and discuss its potential relevance to pathophysiological progress of MS.

Superagonist CD28 antibody preferentially expanded Foxp3-expressing nTreg cells and prevented graft-versus-host diseases.

Regulatory lymphocytes play a pivotal role in preventing organ-specific autoimmune disease and in induction and maintenance of tolerance in various experimental transplantation models. The enhancement of the number and activity of peripheral CD4+CD25+ Treg cells is an obvious goal for the treatment of autoimmunity and for the suppression of alloreactions. The present study demonstrates that naturally occurring CD4+CD25+ Treg (nTreg) cells preferentially proliferate to a fourfold increase within 3 days in response to the administration of a single superagonistic CD28-specific monoclonal antibody (supCD28 mAb). The appearance of increased Foxp3 molecules was accompanied with polarization toward a Th2 cytokine profile with decreased production of IFN-γ and increased production of IL-4 and IL-10 in the expanded Treg subset. Adoptive transfer of supCD28 mAb-expanded cells in a graft-versus-host disease (GvHD) model induced a potent inhibition of lethality. These results suggest that this therapeutic effect is mediated by the in vivo expansion of nTreg cells. Taken together, these data demonstrate that supCD28-mAb may target nTreg cells in vivo and maintain and enhance their potent regulatory functions for the treatment GvHD.

Identification of a novel biomarker gene set with sensitivity and specificity for distinguishing between allograft rejection and tolerance

Here we examined whether the expression of a novel immunoregulatory gene set could be used to predict outcomes in murine models of rapamycin‐induced cardiac tolerance, spontaneous hepatic tolerance, and cardiac rejection. The expression of the immunoregulatory gene set was assessed with the GeXP multiplex reverse‐transcription polymerase chain reaction (RT‐PCR) analysis system, and it was correlated to the pathological and biochemical parameters of the allografts. In rejecting cardiac grafts, the increased expression of an inflammatory set of genes, which included CD45, CD4, CD25, suppressor of cytokine signaling 2, cytotoxic T lymphocyte–associated protein 4 (CTLA4), selectin lymphocyte, interferon‐γ (IFN‐γ), programmed cell death 1 (Pdcd1), and granzyme B (Gzmb), was seen 8 days after transplantation along with histological evidence of severe allograft rejection. In tolerant cardiac allografts, the expression of fibrinogen‐like protein 2 (Fgl2), Pdcd1, killer cell lectin‐like receptor G1 (Klrg1), CTLA4, and lymphocyte‐activation gene 3 was associated with tolerance. In a model of liver allograft tolerance, the increased expression of lectin galactose‐binding soluble 1, Fgl2, CD39, phosphodiesterase 3B, Klrg1, forkhead box P3 (Foxp3), and transforming growth factor β as well as the inflammatory set of genes was observed 8 to 14 days after transplantation (ie, when there was severe inflammatory injury). At a later time when the liver allografts had been fully accepted and were histologically normal, the expression of the inflammatory set of genes returned to the baseline, but the expression of the tolerogenic set of genes was still increased. Genes that were expressed in tolerant cardiac and liver allografts included Fgl2, Klrg1, and Foxp3, whereas genes associated with rejection included CD25, Gzmb, and IFN‐γ. Our data indicate that monitoring the graft expression of a novel biomarker gene set with the GeXP multiplex RT‐PCR analysis system may allow differentiation between rejection and tolerance. Liver Transpl 18:444–454, 2012.

Hydrogen-rich University of Wisconsin solution attenuates renal cold ischemia-reperfusion injury.

Background Renal ischemia-reperfusion (I/R) injury is unavoidable in kidney transplantation and frequently influences both short- and long-term allograft survival rates. One of the major events in I/R injury is the generation of cytotoxic oxygen radicals. Recently, hydrogen gas has been reported to display antioxidant properties and protective effects against organ dysfunction induced by various I/R injuries. We investigated whether hydrogen-rich University of Wisconsin (HRUW) solution attenuates renal cold I/R injury. Methods We prepared HRUW solution by a novel method involving immersion of centrifuge tubes containing UW solution into hydrogen-saturated water. Hydrogen readily permeates through the centrifuge tubes, and thus, the hydrogen concentration of the UW solution gradually increases in a time-dependent manner. Syngeneic rat kidney transplantation was performed, and the animals were divided into three groups: recipients with nonpreserved grafts (control group), recipients with grafts preserved in UW solution for 24 to 48 hr (UW group), and recipients with grafts preserved in HRUW solution for 24 to 48 hr (HRUW group). Results In the early phases, HRUW solution decreased oxidative stress, tubular apoptosis, and interstitial macrophage infiltration in the kidney grafts. Consequently, HRUW solution improved renal function and prolonged recipient survival rate compared with simple cold storage using UW solution. Histopathologically, HRUW treatment alleviated tubular injury and suppressed development of interstitial fibrosis. Conclusions HRUW solution improved graft function and prolonged graft survival compared with simple cold storage using UW solution by protecting tubular epithelial cells from inflammation and apoptosis. Our new method of organ preservation is a groundbreaking, safe, and simple strategy that may be applied in the clinical setting.

The effects of Foxp3-expressing regulatory T cells expanded with CD28 superagonist antibody in DSS-induced mice colitis

Regulatory T (Treg) cells play an important role in the pathogenesis of inflammatory bowel disease (IBD). In the present study, we found that a superagonistic CD28-specific monoclonal antibody (supCD28mAb, D665) could preferentially stimulate expansion of CD4+Foxp3+ Treg cells. Foxp3(EGFP) mice were orally administrated with 3.5% DSS for 5days, and intraperitoneally injected supCD28mAb 1mg/mice in treated group. All of the mice were sacrificed on day 8, and both clinical and histological parameters showed that the severity of colitis was significantly reduced in treated group compared to controls. In treated group, the proportion of CD103, CD152 and CD62L expression on Foxp3+Treg cells in the spleen and mesenteric lymph node were higher than controls. Furthermore, qRT-PCR analysis showed that expression of anti-inflammatory cytokines such as IL-10, TGF-β was significantly increased in treated group. Taken together, our data demonstrated that supCD28mAb targets CD4+Foxp3+Treg cells expansion in vivo, maintains and enhances their regulatory functions, to reduce the damage of colon in dextran sulfate sodium (DSS)-induced mouse colitis by secreting a large amount of IL-10. It represents a major advance towards the therapeutic use of polyclonally activated Treg cells as cellular therapy for treatment of IBD.

Bone marrow-derived conventional, but not cloned, mesenchymal stem cells suppress lymphocyte proliferation and prevent graft-versus-host disease in rats.

Bone marrow-derived mesenchymal stem cells (MSCs) could exert a potent immunosuppressive effect, and therefore may have a therapeutic potential in T-cell-dependent pathologies. In the present study, we aimed to determine whether MSCs could be used to control graft-versus-host disease (GvHD), a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). MSCs were isolated from Lewis rat bone morrow and then cultured in 10% FBS DMEM at 37°C for 4 weeks. The enriched conventional MSCs and macrophages were purified by auto-MACS. Cloned MSCs were obtained by cloning using the limiting dilution method and expanded up to more than 6 months. The identity of MSCs was confirmed by their typical spindle-shaped morphology and immunophenotypic criteria, based on the absence of expression of CD45 and CD11b/c molecules. Both types of MSCs were also tested for their ability to differentiate into adipocytes. We showed that MSCs, like macrophages, exhibit immunomodulatory properties capable of inhibiting T-cell proliferation stimulated by alloantigens, anti-CD3e/CD28 mAbs, and ConA in a dose-dependent manner in vitro. After performing adoptive transfer, MSCs suppressed systemic Lewis to (Lewis × DA)F1 rat GvHD. In contrast to the immunosuppressive activities of conventional MSCs, the cloned MSCs enhanced T-cell proliferation in vitro and yielded no clinical benefit in regard to the incidence or severity of GvHD. Therefore, these rat models have shown intriguing differences in the suppression effects of lymphocyte proliferation and GvHD prevention between short-term cultured conventional MSCs and cloned MSCs.

[11C]DAC-PET for Noninvasively Monitoring Neuroinflammation and Immunosuppressive Therapy Efficacy in Rat Experimental Autoimmune Encephalomyelitis Model

Neuroimaging measures have potential for monitoring neuroinflammation to guide treatment before the occurrence of significant functional impairment or irreversible neuronal damage in multiple sclerosis (MS). N-Benzyl-N-methyl-2-(7-[11C]methyl-8-oxo-2-phenyl-7,8-dihydro-9H-purin-9-yl) acetamide ([11C]DAC), a new developed positron emission tomography (PET) probe for translocator protein 18xa0kDa (TSPO), has been adopted to evaluate the neuroinflammation and treatment effects of experimental autoimmune encephalomyelitis (EAE), an animal model of MS. [11C]DAC-PET enabled visualization of neuroinflammation lesion of EAE by tracing TSPO expression in the spinal cords; the maximal uptake value reached in day 11 and 20 EAE rats with profound inflammatory cell infiltration compared with control, day 0 and 60 EAE rats. Biodistribution studies and in vitro autoradiography confirmed these in vivo imaging results. Doubling immunohistochemical studies showed the infiltration and expansion of CD4+ T cells and CD11b+ microglia; CD68+ macrophages were responsible for the increased TSPO levels visualized by [11C]DAC-PET. Furthermore, mRNA level analysis of the cytokines by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) revealed that TSPO+/CD4 T cells, TSPO+ microglia and TSPO+ macrophages in EAE spinal cords were activated and secreted multiple proinflammation cytokines to mediate inflammation lesions of EAE. EAE rats treated with an immunosuppressive agent: 2-amino-2-[2-(4-octylphenyl)ethyl] propane-1,3-diolhydrochloride (FTY720), which exhibited an absence of inflammatory cell infiltrates, displaying a faint radioactive signal compared with the high accumulation of untreated EAE rats. These results indicated that [11C] DAC-PET imaging is a sensitive tool for noninvasively monitoring the neuroinflammation response and evaluating therapeutic interventions in EAE.

Prolongation of rat major histocompatibility complex-compatible cardiac allograft survival during pregnancy.

BACKGROUNDnIt has been suggested that pregnancy-related hormones play a critical role in mediating selective immune tolerance during pregnancy. An understanding of why a womans body normally does not reject the fetus is highly relevant to the prevention of transplant rejection.nnnMETHODSnThe hearts of female inbred F344 rats (RT-1(lvl)) were transplanted into naive Lewis (RT-1(l); nLewis) or pregnant (pLewis; Day 6, 12 and 18 of pregnancy) rats. The mean survival time (MST) of the cardiac allografts between the nLewis and pLewis rats was compared. We determined the rate of proliferation of the T cells isolated from nLewis and pLewis rats in response to concanavalin A (ConA), anti-CD3 and -CD28 antibody and alloantigen stimulation ex vivo. mRNA expression of several cytokines in these T cells was analyzed using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). In addition, the effect of estriol on the cardiac allograft was tested.nnnRESULTSnThe pLewis rats with transplant on Day 12 of pregnancy had the most significantly prolonged F344 cardiac graft survival (MST 13.3 days) as compared with nLewis recipients (MST 8 days). pLewis T-cell proliferation was stimulated by alloantigen and antibody but ConA was reduced, whereas Th1/Th2 cytokine mRNA profiles in the T cells were similar for nLewis and pLewis rats. Likewise, estriol also significantly prolonged survival of cardiac allografts.nnnCONCLUSIONSnThe results of this study demonstrate that pregnancy hormones not only appear to play a critical role in maternal acceptance of the fetus, but also have therapeutic potential for prolonging the survival of major histocompatibility complex (MHC)-compatible allografts during pregnancy.