Increased Expression and a Potential Anti-Inflammatory Role of TRAIL in Atopic Dermatitis

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis of many transformed but also of non-transformed cells. In addition, TRAIL receptor activation has been reported to activate non-apoptotic signaling pathways. Here, we report an increased expression of TRAIL in peripheral blood T cells and monocytes from patients with atopic dermatitis (AD) compared with control individuals. High TRAIL expression was also observed in skin-infiltrating T cells of AD patients. Topical tacrolimus treatment reduced the total number of T cells in the skin, but the relative proportion of TRAIL-positive cells within both CD4+ and CD8+ cell populations did not change. TRAIL was demonstrated to induce the expression of interleukin-1 receptor antagonist (IL-1Ra) in keratinocytes in a caspase-independent manner in vitro. Moreover, increased expression of IL-1Ra was observed in keratinocytes of AD lesional skin. These data suggest that TRAIL-expressing inflammatory skin cells may contribute to the epidermal activation of the IL-1Ra gene in AD.

Targeted gene therapy of autoimmune diseases: advances and prospects

Idealized gene therapy of autoimmune diseases would mean getting the right drug to the right place at the right time to affect the right mechanism of action. In other words, a specific gene therapy strategy needs to have functional, spatial and temporal specificity. Functional specificity implies targeting the cellular, molecular and/or genetic mechanisms relevant to the disease, without affecting nondiseased organs or tissues through mechanisms that cause adverse effects. Spatial specificity means the delivery of the therapeutic agent exclusively to sites and cells that are relevant to the disease. Temporal specificity is, in principle, synonymous with controlled on-demand expression of the therapeutic gene and thus represents a major safety feature. This article reviews recent advances in strategies to use gene therapy in the treatment of autoimmune diseases.

Role of glucocorticoid‐induced TNF receptor family gene (GITR) in collagen‐induced arthritis

In rheumatoid arthritis (RA), a widespread autoimmune/inflammatory joint disease, early activation of effector CD4+ T lymphocytes, and cytokine production is followed by recruitment of other inflammatory cells, production of a range of inflammation mediators, tissue damage, and disease. GITR (glucocorticoid-induced TNFR family-related gene), a costimulatory molecule for T lymphocytes, increases CD4+CD25- effector T cell activation while inhibiting suppressor activity of CD4+CD25+ T regulatory (Treg) cells. We analyzed the role of GITR in type II collagen (CII) -induced arthritis (CIA) using GITR-/- and GITR+/+ mice. Results indicate significantly less CIA induction in GITR-/- mice than in GITR+/+ mice, with marked differences in erythema, edema, neutrophil infiltration, joint injury, and bone erosion. Production of IFNgamma, IL-6, TNFalpha, MIP-1alpha, and MIP-2, inducible NOS (iNOS), COX-2, and nitrotyrosine poly-ADP-ribose (PAR) were also less in CII-treated GITR-/- mice. Although CD4+CD25+ Treg cells from GITR+/+ and GITR-/- CII-challenged mice exerted similar suppressor activity in vitro, GITR triggering abrogated GITR+/+ Treg suppressor activity and costimulated CD4+CD25- GITR+/+ effector cells. Furthermore, Treg cells from GITR-/- protected more than Treg cells from GITR+/+ mice against CIA when cotransferred with Treg-depleted splenocytes from arthritic GITR+/+ animals into severe combined immunodeficient (SCID) mice. In conclusion, GITR plays a critical role in the immunological response against CII and in the development of CIA.

TRAIL-Transduced Dendritic Cells Protect Mice from Acute Graft-versus-Host Disease and Leukemia Relapse

TRAIL preferentially induces apoptotic cell death in a wide variety of transformed cells, whereas it induces no apoptosis, but inhibits activation of Ag-specific T cells via blockade of cell cycle progression. Although accumulating results suggest that TRAIL is involved in the maintenance of immunological homeostasis under steady state conditions as well as in the initiation and progression of immunopathologies, the potential regulatory effect of TRAIL on immune responses and its therapeutic potential in immunological diseases remains unclear. We report in this study the potential usefulness of TRAIL-transduced dendritic cells (DCs) for the treatment of lethal acute graft-vs-host disease (GVHD) and leukemia relapse. DCs genetically modified to express TRAIL showed potent cytotoxicity against both alloreactive T cells and leukemic cells through the induction of apoptosis. In addition, treatment with genetically modified DCs expressing TRAIL of allogeneic BM transplants recipients with leukemia was effective for protection against acute GVHD and leukemia relapse. Thus, gene transfer of TRAIL to DCs is a novel modality for the treatment of acute GVHD and leukemia relapse by selective targeting of pathogenic T cells and leukemic cells.

Genetic segregation of spontaneous erosive arthritis and generalized autoimmune disease in the BXD2 recombinant inbred strain of mice

The BXD2 strain of mice is one of approximately 80 BXD recombinant inbred (RI) mouse strains derived from an intercross between C57BL/6J (B6) and DBA/2J (D2) strains. We have discovered that adult BXD2 mice spontaneously develop generalized autoimmune disease, including glomerulonephritis (GN), increased serum titres of rheumatoid factor (RF) and anti-DNA antibody, and a spontaneous erosive arthritis characterized by mononuclear cell infiltration, synovial hyperplasia, and bone and cartilage erosion. The features of lupus and arthritis developed by the BXD2 mice segregate in F2 mice generated by crossing BXD2 mice with the parental B6 and D2 strains. Genetic linkage analysis of the serum levels of anti-DNA and RF by using the BXD RI strains shows that the serum titers of anti-DNA and RF were influenced by a genetic locus on mouse chromosome (Chr) 2 near the marker D2Mit412 (78 cm, 163 Mb) and on Chr 4 near D4Mit146 (53.6 cm, 109 Mb), respectively. Both loci are close to the B-cell hyperactivity, lupus or GN susceptibility loci that have been identified previously. The results of our study suggest that the BXD2 strain of mice is a novel model for complex autoimmune disease that will be useful in identifying the mechanisms critical for the immunopathogenesis and genetic segregation of lupus and erosive arthritis.

Novel concepts and treatments for autoimmune disease: ten focal points

Understanding the development of autoimmunity is a crucial step toward improving the management, not only of autoimmune diseases, but also of tumors and primary immunodeficiency syndromes. The rapid expansion of knowledge on autoimmunity is fueling the development of a novel approach known as targeted immunotherapy. The present review will concentrate on ten areas where major advances have been achieved: 1) early regulation of B-cell mediated autoimmunity; 2) thymic regulation of tolerance to tissue-restricted antigens via the transcription factor AIRE; 3) role for a population of regulatory T cells (CD4+ CD25+ Tregs) with unique effects; 4) major role for dendritic cells in the development of autoimmunity in conditions such as lupus; 5) role for T cells in autoimmune diseases; 6) role for T cells in rheumatoid arthritis, with new data from a murine model of spontaneous arthritis related to a ZAP-70 mutation; 7) role for the environment via innate immunity, in particular mediated by the toll-like receptors (TLR); identification of new autoantigens with the description of sense-antisense peptides (e.g., proteinase 3-complementary proteinase 3); the immunosenescence concept, which suggests that some autoimmune diseases may be related to premature aging of the immune system; 10) identification of new immunotherapy targets, including costimulation pathway molecules (CD28, CTLA4), original activation systems (BAFF/BLyS), and receptors such as TLRs. These exciting insights into the pathogenic mechanisms underlying immune dysfunction will play a key role in advancing the field of immunorheumatology.

Prevention of Experimental Autoimmune Encephalomyelitis by Transfer of Embryonic Stem Cell-Derived Dendritic Cells Expressing Myelin Oligodendrocyte Glycoprotein Peptide along with TRAIL or Programmed Death-1 Ligand

Experimental autoimmune encephalomyelitis (EAE) is caused by activation of myelin Ag-reactive CD4+ T cells. In the current study, we tested a strategy to prevent EAE by pretreatment of mice with genetically modified dendritic cells (DC) presenting myelin oligodendrocyte glycoprotein (MOG) peptide in the context of MHC class II molecules and simultaneously expressing TRAIL or Programmed Death-1 ligand (PD-L1). For genetic modification of DC, we used a recently established method to generate DC from mouse embryonic stem cells (ES cells) in vitro (ES-DC). ES cells were sequentially transfected with an expression vector for TRAIL or PD-L1 and an MHC class II-associated invariant chain-based MOG epitope-presenting vector. Subsequently, double-transfectant ES cell clones were induced to differentiate to ES-DC, which expressed the products of introduced genes. Treatment of mice with either of the double-transfectant ES-DC significantly reduced T cell response to MOG, cell infiltration into spinal cord, and the severity of MOG peptide-induced EAE. In contrast, treatment with ES-DC expressing MOG alone, irrelevant Ag (OVA) plus TRAIL, or OVA plus PD-L1, or coinjection with ES-DC expressing MOG plus ES-DC-expressing TRAIL or PD-L1 had no effect in reducing the disease severity. In contrast, immune response to irrelevant exogenous Ag (keyhole limpet hemocyanin) was not impaired by treatment with any of the genetically modified ES-DC. The double-transfectant ES-DC presenting Ag and simultaneously expressing immune-suppressive molecules may well prove to be an effective therapy for autoimmune diseases without inhibition of the immune response to irrelevant Ag.

Gene therapy for autoimmune diseases: quo vadis?

Biological therapies using antibodies and cytokines are becoming widespread for the treatment of chronic inflammatory autoimmune diseases. However, these treatments have several limitations - such as expense, the need for repeated injections and unwanted side-effects - that can be overcome by genetic delivery. This review summarizes the ingenuity, sophistication and variety of gene-therapy approaches that have been taken in the design of therapeutic molecules and vectors, the engineering of cells and the regulation of gene expression for the targeting of disease outcome. We focus our attention on multiple sclerosis, type 1 diabetes and rheumatoid arthritis.

T lymphocytes in systemic lupus erythematosus: an update

PURPOSE OF REVIEW

T cells from patients with systemic lupus erythematosus have been shown to be activated in vivo and provide cognate and noncognate help to autoreactive B cells. In particular, T cells exhibit aberrant responses to stimuli with increased calcium influx and decreased production of interferon-gamma and interleukin-2. An imbalance in the proapoptotic/antiapoptotic mechanisms also seems to contribute to the persistence of autoreactive clones and the lack of productive immune responses. The purpose of this review is to discuss recent studies that shed light into the pathogenetic mechanisms underlying T-cell dysfunction in systemic lupus erythematosus.

RECENT FINDINGS

Significant progress has been made in understanding the causes of the abnormal T-cell receptor and other surface molecule-mediated signaling. Furthermore, investigators have characterized better the intracellular and nuclear signaling pathways that lead to abnormal cytokine production in lupus. Finally, efforts to correct these abnormalities in vitro have yielded promising results.

SUMMARY

New findings in the pathophysiology of T cells in lupus and especially the application of novel techniques to correct immune cell aberrations on the transcriptional and translational levels give hope for the development of rational treatments in systemic lupus erythematosus.