Search

Sclerodermatous graft-versus-host disease, a frequent complication of allogeneic hematopoietic stem cell graft, shares many features with systemic sclerosis, such as production of autoantibodies and fibrosis of skin and inner organs. Recent reports on the implication of signal transducer and activator of transcription 3 and of Wnt/β-catenin in fibrosis have prompted us to investigate the effects of the inhibition of both signaling pathways in a mouse model of sclerodermatous graft-versus-host disease, using niclosamide, an anthelmintic drug, with a well-defined safety profile. Sclerodermatous graft-versus-host disease was induced in BALB/c mice by B10.D2 bone marrow and spleen cell transplantation. Mice were treated every other day, 5 days a week, for 5 weeks by niclosamide. Clinical and biological features were studied 42 days after transplantation. Niclosamide reversed clinical symptoms including alopecia, vasculitis, and diarrhea and prevented fibrosis of the skin and visceral organs. Beneficial immunological effects were also observed: niclosamide decreased the production of effector memory CD4 and CD8 T cells, T-cell infiltration of the skin and visceral organs, and decreased productions of IL-4 and IL-13, and autoimmune B-cell activation. The improvement provided by niclosamide in the mouse model of sclerodermatous graft-versus-host disease provides a rationale for the evaluation of niclosamide in the management of patients affected by systemic fibrotic disease., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Chronic graft-versus-host disease (GVHD) follows allogeneic hematopoietic stem cell transplantation. It results from alloreactive processes induced by minor histocompatibility antigen incompatibilities leading to the activation of CD4 T cells and the development of fibrosis and inflammation of the skin and visceral organs and autoimmunity that resemble systemic sclerosis. EGFR is a ubiquitous cell receptor deeply involved in cell proliferation, differentiation, and motility. EGFR has recently been implicated in autoimmune and fibrotic diseases. Therefore, we tested whether Erlotinib, an EGFR tyrosine kinase inhibitor, can prevent sclerodermatous GVHD (Scl-GVHD). Scl-GVHD was induced in BALB/c mice by B10.D2 bone marrow and spleen cell transplantation. Transplanted mice displayed severe clinical symptoms including alopecia, fibrosis of the skin and visceral organs, vasculitis, and diarrhea. The symptoms were reversed in mice treated with Erlotinib. These beneficial effects were mediated by the decreased production of activated/memory CD4(+) T cells and the reduction in T-cell infiltration of the skin and visceral organs along with a decrease in IFN-γ and IL-13 production and autoimmune B-cell activation. The improvement provided by Erlotinib in the mouse model of Scl-GVHD supplies a rationale for the evaluation of Erlotinib in the management of patients affected by chronic GVHD.

Systemic sclerosis (SSc) is a connective tissue disorder characterized by skin and visceral fibrosis, microvascular damage, and autoimmunity. HOCl-induced mouse SSc is a murine model that mimics the main features of the human disease, especially the activation and hyperproliferation rate of skin fibroblasts. We demonstrate here the efficiency of a tellurium-based catalyst 2,3-bis(phenyltellanyl)naphthoquinone ((PHTE)(2)NQ) in the treatment of murine SSc, through its selective cytotoxic effects on activated SSc skin fibroblasts. SSc mice treated with (PHTE)(2)NQ displayed a significant decrease in lung and skin fibrosis and in alpha-smooth muscle actin (α-SMA) expression in the skin compared with untreated mouse SSc animals. Serum concentrations of advanced oxidation protein products, nitrate, and anti-DNA topoisomerase I autoantibodies were increased in SSc mice, but were significantly reduced in SSc mice treated with (PHTE)(2)NQ. To assess the mechanism of action of (PHTE)(2)NQ, the cytotoxic effect of (PHTE)(2)NQ was compared in normal fibroblasts and in mouse SSc skin fibroblasts. ROS production is higher in mouse SSc fibroblasts than in normal fibroblasts, and was still increased by (PHTE)(2)NQ to reach a lethal threshold and kill mouse SSc fibroblasts. Therefore, the effectiveness of (PHTE)(2)NQ in the treatment of mouse SSc seems to be linked to the selective pro-oxidative and cytotoxic effects of (PHTE)(2)NQ on hyperproliferative fibroblasts.

Deep infiltrating endometriosis (DIE) is a particular clinical and histological entity of endometriosis responsible for chronic pelvic pain and infertility. Here we characterize the proliferative phenotype of DIE cells, to explore the cellular and molecular mechanisms that could explain their aggressive potential. In addition, the inhibition of mTOR/AKT pathway was tested, as a potential treatment of DIE. Included were 22 patients with DIE and 12 control patients without endometriosis. Epithelial and stromal cells were extracted from biopsies of eutopic endometrium and deep infiltrating endometriotic nodules from patients with DIE. Cell proliferation was determined by thymidine incorporation. Oxidative stress was assayed by spectrofluorometry. The ERK and mTOR/AKT pathways were analyzed in vitro by Western blot and for AKT in vivo in a mouse model of DIE. The proliferation rate of eutopic endometrial cells and of deep infiltrating endometriotic cells from DIE patients was higher than that of endometrial cells from controls. The hyperproliferative phenotype of endometriotic cells was associated with an increase in endogenous oxidative stress, and with activation of the ERK and mTOR/AKT pathways. mTOR/AKT inhibition by temsirolimus decreased endometriotic cell proliferation both in vitro and in vivo in a mouse model of DIE. Blocking the mTOR/AKT pathway offers new prospects for the treatment of DIE., (Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Deep infiltrating endometriosis (DIE) is characterized by chronic pain, hyperproliferation of endometriotic cells and fibrosis. Since cannabinoids are endowed with antiproliferative and antifibrotic properties, in addition to their psychogenic and analgesic effects, cannabinoid agonists have been evaluated in DIE both in vitro and in vivo. The in vitro effects of the cannabinoid agonist WIN 55212-2 were evaluated on primary endometriotic and endometrial stromal and epithelial cell lines extracted from patients with or without DIE. Cell proliferation was determined by thymidine incorporation and production of reactive oxygen species by spectrofluorometry. ERK and Akt pathways were studied by immunoblotting. Immunoblotting of α-smooth muscle actin was studied as evidence of myofibroblastic transformation. The in vivo effects of WIN 55212-2 were evaluated on Nude mice implanted with human deep infiltrating endometriotic nodules. The in vitro treatment of stromal endometriotic cells by WIN 55212-2 decreased cell proliferation, reactive oxygen species production, and α-smooth muscle actin expression. The decrease in cell proliferation induced by WIN 55212-2 was not associated with a decrease in ERK activation, but was associated with the inhibition of Akt activation. WIN 55212-2 abrogated the growth of endometriotic tissue implanted in Nude mice. Cannabinoid agonists exert anti-proliferative effects on stromal endometriotic cells linked to the inhibition of the Akt pathway. These beneficial effects of cannabinoid agonists on DIE have been confirmed in vivo.

Our aim was to evaluate the roles of the cannabinoid pathway in the induction and propagation of systemic sclerosis (SSc) in a mouse model of diffuse SSc induced by hypochlorite injections. BALB/c mice injected subcutaneously every day for 6 weeks with PBS or hypochlorite were treated intraperitoneally with either WIN-55,212, an agonist of the cannabinoid receptors 1 (CB1) and receptors 2 (CB2), with JWH-133, a selective agonist of CB2, or with PBS. Skin and lung fibrosis were then assessed by histological and biochemical methods, and the proliferation of fibroblasts purified from diseased skin was assessed by thymidine incorporation. Autoantibodies were detected by ELISA, and spleen cell populations were analyzed by flow cytometry. Experiments were also performed in mice deficient for CB2 receptors (Cnr2(-/-)). Injections of hypochlorite induced cutaneous and lung fibrosis as well as increased the proliferation rate of fibroblasts isolated from fibrotic skin, splenic B cell counts, and levels of anti-DNA topoisomerase-1 autoantibodies. Treatment with WIN-55,212 or with the selective CB2 agonist JWH-133 prevented the development of skin and lung fibrosis as well as reduced fibroblast proliferation and the development of autoantibodies. Experiments performed in CB2-deficient mice confirmed the influence of CB2 in the development of systemic fibrosis and autoimmunity. Therefore, we demonstrate that the CB2 receptor is a potential target for the treatment of SSc because it controls both skin fibroblast proliferation and the autoimmune reaction.

Endometriosis is associated with chronic inflammation, and reactive oxygen species (ROS) are proinflammatory mediators that modulate cell proliferation. We have investigated whether the dysregulation of ROS production in endometriotic cells correlates with a pro-proliferative phenotype and can explain the spreading of this disease. Stromal and epithelial cells were purified from ovarian endometrioma and eutopic endometrium from 14 patients with endometriosis to produce four primary cell lines from each patient. ROS production, detoxification pathways, cell proliferation, and mitogen-activated protein kinase pathway activation were studied and compared with epithelial and stromal cell lines from 14 patients without endometriosis. Modulation of the proliferation of endometriosis by N-acetyl-cysteine, danazol, and mifepristone was tested in vitro and in 28 nude mice implanted with endometriotic tissue of human origin. Endometriotic cells displayed higher endogenous oxidative stress with an increase in ROS production, alterations in ROS detoxification pathways, and a drop in catalase levels, as observed for tumor cells. This increase in endogenous ROS correlated with increased cellular proliferation and activation of ERK1/2. These phenomena were abrogated by the antioxidant molecule N-acetyl-cysteine both in vitro and in a mouse model of endometriosis. Human endometriotic cells display activated pERK, enhanced ROS production, and proliferative capability. Our murine model shows that antioxidant molecules could be used as safe and efficient treatments for endometriosis.

Exosomes are secreted vesicles formed in late endocytic compartments. Immature dendritic cells (DCs) secrete exosomes, which transfer functional major histocompatibility complex (MHC)-peptide complexes to other DCs. Since immature and mature DCs induce different functional T-cell responses (ie, tolerance versus priming), we asked whether DC maturation also influenced the priming abilities of their exosomes. We show that exosomes secreted by lipopolysaccharide (LPS)-treated mature DCs are 50- to 100-fold more potent to induce antigen-specific T-cell activation in vitro than exosomes from immature DCs. In vitro, exosomes from mature DCs transfer to B lymphocytes the ability to prime naive T cells. In vivo, only mature exosomes trigger effector T-cell responses, leading to fast skin graft rejection. Proteomic and biochemical analyses revealed that mature exosomes are enriched in MHC class II, B7.2, intercellular adhesion molecule 1 (ICAM-1), and bear little milk-fat globule-epidermal growth factor-factor VIII (MFG-E8) as compared with immature exosomes. Functional analysis using DC-derived exosomes from knock-out mice showed that MHC class II and ICAM-1 are required for mature exosomes to prime naive T cells, whereas B7.2 and MFG-E8 are dispensable. Therefore, changes in protein composition and priming abilities of exosomes reflect the maturation signals received by DCs.