Transforming growth factor-ß increases interleukin-13 synthesis via GATA-3 transcription factor in T-lymphocytes from patients with systemic sclerosis.

INTRODUCTION: Transforming growth factor (TGF)-ß and interleukin (IL)-13 play a crucial role in the pathogenesis of systemic sclerosis (SSc), partly through activation of collagen production that leads to fibrosis. The aim of the present study was to determine whether TFG-ß alters IL-13 production in T lymphocytes from patients with SSc from that seen in those of healthy donors. METHODS: IL-13 mRNA and protein synthesis under TFG-ß exposure was measured in circulating T lymphocytes from healthy donors and patients with SSc and also in the Jurkat Th2 T-cell line, using quantitative real-time PCR and fluorescence-activated cell sorting analysis, respectively. The involvement of Smad and GATA-3 transcription factors was assessed by using specific inhibitors and small interfering RNA, and the binding capacity of GATA-3 to the IL-13 gene promoter was evaluated by chromatin immunoprecipitation assay. RESULTS: TGF-ß induced a significant decrease in IL-13 mRNA and protein levels in lymphocytes from healthy donors (mean [±SD] inhibition of 30% ± 10% and 20% ± 7%, respectively; p < 0.05). In contrast, TGF-ß promoted a significant increase in IL-13 mRNA levels and IL-13 synthesis by CD4(+) and CD8(+) T-cell subtypes from patients with SSc, with respective increases of 2.4 ± 0.3-fold, 1.6 ± 0.05-fold and 2.7 ± 0.02-fold. The involvement of the Smad signaling pathway and upregulation of GATA-3 binding capacity on the IL-13 promoter in lymphocytes from patients with SSc contributed to the effect of TGF-ß on IL-13 production. CONCLUSIONS: These results demonstrate that TGF-ß upregulates IL-13 synthesis through GATA-3 expression in the T lymphocytes of patients with SSc, confirming that the GATA-3 transcription factor can be regarded as a novel therapeutic target in patients with SSc.

Expression of transforming growth factor ß receptor II in mesenchymal stem cells from systemic sclerosis patients.

OBJECTIVES: The present work aimed to evaluate the expression of transforming growth factor-ß (TGF-ß) receptors on bone marrow-derived multipotent mesenchymal stromal cells (MSCs) in patients with systemic sclerosis (SSc) and the consequences of TGF-ß activation in these cells, since MSC have potential therapeutic interest for SSc patients and knowing that TGF-ß plays a critical role during the development of fibrosis in SSc. DESIGN: This is a prospective research study using MSC samples obtained from SSc patients and compared with MSC from healthy donors. SETTING: One medical hospital involving collaboration between an internal medicine department for initial patient recruitment, a clinical biotherapeutic unit for MSC preparation and an academic laboratory for research. PARTICIPANTS: 9 patients with diffuse SSc for which bone marrow (BM) aspiration was prescribed by sternum aspiration before haematopoietic stem cell transplantation, versus nine healthy donors for normal BM. PRIMARY AND SECONDARY OUTCOME MEASURES: TGF-ß, TGF-ß receptor types I (TBRI) and II (TBRII) mRNA and protein expression were assessed by quantitative PCR and flow cytometry, respectively, in MSC from both SSc patients and healthy donors. MSC were exposed to TGF-ß and assessed for collagen 1α2 synthesis and Smad expression. As positive controls, primary cultures of dermal fibroblasts were also analysed. RESULTS: Compared with nine controls, MSC from nine SSc patients showed significant increase in mRNA levels (p<0.002) and in membrane expression (p<0.0001) of TBRII. In response to TGF-ß activation, a significant increase in collagen 1α synthesis (p<0.05) and Smad-3 phosphorylation was upregulated in SSc MSC. Similar results were obtained on eight SSc-derived dermal fibroblasts compared to six healthy controls. CONCLUSIONS: TBRII gene and protein expression defect in MSC derived from SSc patients may have pathological significance. These findings should be taken into account when considering the use of MSC-based therapies in an autologous setting.

Relationship between cytokine profiles and clinical outcomes in patients with systemic sclerosis.

Although the pathogenesis of systemic sclerosis (SSc) remains unknown, cytokine production and release are key events in this autoimmune disease, characterized by T cell activation and auto-antibodies production leading to microvascular damage, inflammation and fibrosis. We review herein experimental and clinical data, aiming to analyze the relationship between cytokine release and SSc pathogenesis. Measurement of circulating or in situ cytokine levels provides evidence for a balance between "Th1/Th2" or "Th17/Treg" cytokines in the development of SSc. Indeed, the Th2 cytokine response, with the production of IL-4, IL-10 and TGF-ß, leads to tissue fibrosis, whereas Th1 and Th17 cytokines promote inflammation in SSc patients. Thus, cytokine levels have been assessed as diagnostic or prognostic markers in SSc patients. Restoration of the Th1/Th2/Th17/Treg balance is one of the hallmarks of treatment effectiveness and development of cytokine modulators could be considered for new therapeutic approaches in SSc patients.