Browsing by Subject "Systemic sclerosis"

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Open Access
Evaluation of X chromosome inactivation with respect to HLA genetic susceptibility in rheumatoid arthritis and systemic sclerosis
(Public Library of Science, 2016) Kanaan, S. B.; Onat, O. E.; Balandraud, N.; Martin, G. V.; Nelson, J. L.; Azzouz, D. F.; Auger, I.; Arnoux, F.; Martin, M.; Roudier, J.; Ozcelik, T.; Lambert, N. C.
Background: Autoimmune diseases, including rheumatoid arthritis (RA) and systemic sclerosis (SSc) are characterized by a strong genetic susceptibility from the Human Leucocyte Antigen (HLA) locus. Additionally, disorders of epigenetic processes, in particular non-random X chromosome inactivation (XCI), have been reported in many female-predominant autoimmune diseases. Here we test the hypothesis that women with RA or SSc who are strongly genetically predisposed are less susceptible to XCI bias. Methods: Using methylation sensitive genotyping of the androgen receptor (AR) gene, XCI profiles were performed in peripheral blood mononuclear cells from 161 women with RA, 96 women with SSc and 100 healthy women. HLA-DRB1 and DQB1 were genotyped. Presence of specific autoantibodies was documented for patients. XCI skewing was defined as having a ratio ≥ 80:20 of cells inactivating the same X chromosome. Results: 110 women with RA, 68 women with SSc, and 69 controls were informative for the AR polymorphism. Among them 40.9% of RA patients and 36.8% of SSc patients had skewed XCI compared to 17.4% of healthy women (P = 0.002 and 0.018, respectively). Presence of RA-susceptibility alleles coding for the "shared epitope" correlated with higher skewing among RA patients (P = 0.002) and such correlation was not observed in other women, healthy or with SSc. Presence of SSc-susceptibility alleles did not correlate with XCI patterns among SSc patients. Conclusion: Data demonstrate XCI skewing in both RA and SSc compared to healthy women. Unexpectedly, skewed XCI occurs more often in women with RA carrying the shared epitope, which usually reflects severe disease. This reinforces the view that loss of mosaicism in peripheral blood may be a consequence of chronic autoimmunity. © 2016 Kanaan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Open Access
Skewed X chromosome inactivation in blood cells of women with scleroderma
(John Wiley & Sons, Inc., 2005) Özbalkan, Z.; Baǧişlar, S.; Kiraz, S.; Akyerli, C. B.; Özer H. T. E.; Yavuz, Ş.; Birlik, A. M.; Çalgüneri, M.; Özçelik, T.
Objective. Scleroderma (SSc) is an autoimmune disease of unknown etiology. The disease is 3-8 times more frequent in women than in men. The role of X chromosome inactivation (XCI) in the predisposition of women to autoimmunity has been questioned. Until now this has not been illustrated experimentally. This study was undertaken to test the hypothesis that disturbances in XCI mosaicism may be involved in the pathogenesis of the disease in female patients with SSc. Methods. Seventy female SSc patients and 160 female controls were analyzed for the androgen receptor locus by the Hpa II/polymerase chain reaction assay to assess XCI patterns in DNA extracted from peripheral blood cells. Furthermore, skin biopsy samples were obtained from 5 patients whose blood revealed an extremely skewed pattern of XCI, and the analysis repeated. Since microchimerism in SSc was reported, Y chromosome sequences were investigated in all samples. Results. Skewed XCI was observed in DNA from peripheral blood cells in 35 of 55 informative patients (64%), as compared with 10 of 124 informative controls (8%) (P < 0.0001). Extreme skewing was present in 27 of the patient group (49%), as compared with only 3 of the controls (2.4%) (P < 0.0001). However, XCI was random in all skin biopsy samples. The potential contribution of microchimerism to the random XCI pattern is highly unlikely based on the medical histories of the patients. Conclusion. Skewed XCI mosaicism may play a significant role in the pathogenesis of SSc.
Open Access
Therapeutic potential of an immunosuppressive oligodeoxynucleotide encapsulated within liposomes on bleomycin-induced mouse model of lung inflammation and fibrosis
(2019-05) Kılıç, Gizem
Systemic sclerosis (SSc) is an autoimmune/autoinflammatory disease with unknown etiology. It is characterized by vascular dysfunction, inflammation and disseminated fibrosis of skin or internal organs. Although its prevalence is low, development of fibrosis on internal organs and lack of a curative treatment result in high morbidity. Current therapies targeting specific symptoms such as interstitial lung disease, Raynaud’s phenomenon and pulmonary arterial hypertension are inefficient, and at best, temporarily relieves the symptoms throughout the course of the treatment. Herein, we investigated the therapeutic potential of an immunosuppressive oligodeoxynucleotide expressing TTAGGG telomeric repeats which is known as the “A151 ODN” on bleomycin-induced mouse model of systemic sclerosis. A151 ODN is the single stranded synthetic form of the telomeric repeat sequence expressed on mammalian chromosome, and it contains four repeats of “TTAGGG” motif. In order to enhance the therapeutic effectivity while protecting its digestion from nuclease activity following administration, we encapsulated A151 ODN within anionic liposomes. Since pattern recognition receptors and their signaling pathways were demonstrated to initiate inflammation in SSc, we first explored the immunosuppressive capacity of A151 ODN by analyzing in vitro cytokine productions and surface marker expression levels. Similar with the previous findings, A151 ODN was highly potent to abolish cytokine production in response to TLR9 induction. Although A151 ODN by itself was not very effective to suppress cytokine secretion following TLR1/2 and TLR4 induction, encapsulation within anionic liposomes further improved the immunosuppressive potential in response to TLR engagement. Furthermore, flow cytometry analyses revealed that A151 ODN decreased antigen presentation capacity and activation of bone-marrow derived macrophages (BMDMs) in response to TLR stimulation which was demonstrated by the reduction in levels of surface MHCII and co-stimulatory molecules as well as proteins having role on macrophage adherence and migration. A151 ODN also inhibited transcription of two major genes known to play a critical role on the development of fibrosis, TGFβ and Col1a1, from fibroblasts. Following these promising results on A151 ODN’s immunosuppressive and anti-fibrotic potential, we tested its therapeutic role on bleomycin-induced lung inflammation and fibrosis on mice which reflects different phases of systemic sclerosis. First in vivo experiment that A151 ODN was used prior to bleomycin administration revealed that A151 ODN could prevent development of systemic sclerosis by reducing immune cell recruitment into alveolar space and suppressing the secretion of inflammatory cytokines. After that, we investigated if A151 ODN could abolish established lung inflammation triggered by bleomycin instillation. For that, we treated animals with an A151 ODN either in free form or encapsulated within anionic liposomes after lung inflammation was initiated following bleomycin instillation. Data indicated that A151 ODN reduced macrophage activation marker expressions, monocyte and neutrophil infiltration into alveolar space. Moreover, suppression on immune cells activation in bronchoalveolar lavage fluid (BALF) correlated with the inhibited cytokine production. As a result of reduced inflammation, pro-fibrotic gene expressions were less in A151 ODN-treated mice. Of note, liposomal encapsulation provided reduced gene expressions while failed to further enhance the immunosuppressive potential on surface marker expression or cytokine secretion of A151 ODN. Lastly, we tested whether treatment with liposome-encapsulated A151 ODN is still effective to regress fibrosis once it has been developed; therefore, we treated mice with single injection of liposomal A151 on different time points. Unfortunately, single instillation was insufficient to decrease fibrosis and macrophage activation as well as cytokine production. Taken together, our findings indicated that liposome-encapsulated A151 ODN is very potent to attenuate the lung inflammation whereas single injection was ineffective to regress established lung fibrosis.