Th17 cells favor inflammatory responses while inhibiting type I collagen deposition by dermal fibroblasts: Differential effects in healthy and systemic sclerosis fibroblasts

Arthritis research & therapy (Impact Factor: 3.75). 10/2013; 15(5):R151. DOI: 10.1186/ar4334
Source: PubMed


T helper (Th)-17 cells are increased in systemic sclerosis (SSc). We therefore assessed whether Th17 cells could modulate the inflammatory and fibrotic responses in dermal fibroblasts from healthy donors (HD) and SSc individuals.
Fibroblasts were obtained from 14 SSc and 8 HD skin biopsies. Th17 clones were generated from healthy peripheral blood upon enrichment of CC chemokine receptor (CCR)-4/CCR6/CD161 expressing cells. Their cytokine production was assessed by flow cytometry and multiplex beads immunoassay. Fibroblast production of monocyte chemoattractant protein (MCP)-1, interleukin (IL)-8, matrix metalloproteinase (MMP)-1, tissue inhibitor of metalloproteinase (TIMP)-1, MMP-2 and type-I collagen was quantified by enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (RIA), and changes in their transcription levels assessed by real-time PCR. Intracellular signals were dissected by western blot and the use of pharmacological inhibitors. IL-17A, tumor necrosis factor (TNF) and interferon-gamma (IFN-γ) blocking reagents were used to assess the specificity of the observed effects.
IL-17A increased MCP-1, IL-8 and MMP-1 production in a dose-dependent manner while having no effect on type I collagen in HD and SSc fibroblasts both at protein and mRNA levels. Nuclear factor-kappa B (NF-κB) and p38 were preferentially involved in the induction of MCP-1 and IL-8, while MMP-1 was most dependent on c-Jun N-terminal kinase (JNK). Supernatants of activated Th17 clones largely enhanced MCP-1, IL-8 and MMP-1 while strongly inhibiting collagen production. Of note, the production of MCP-1 and IL-8 was higher, while collagen inhibition was lower in SSc compared to HD fibroblasts. The Th17 clone supernatant effects were mostly dependent on additive/synergistic activities between IL-17A, TNF and in part IFN-γ. Importantly, the inhibition of type I collagen production induced by the Th17 clone supernatants was completely abrogated by blockade of IL-17A, TNF and IFN-γ mostly in SSc fibroblasts, revealing an intrinsic resistance to inhibitory signals in SSc.
Our findings demonstrate that in vitro Th17 cells elicit pro-inflammatory responses while restraining collagen production. Thus, the increased Th17 cell number observed in SSc may impact on the inflammatory component of the disease simultaneously potentially providing a protective role against fibrosis.

Download full-text


Available from: Nicolo Costantino Brembilla, Aug 15, 2014
  • Source
    • "Inflammatory cells need an appropriate local cytokine concentration to be able to migrate, and at the same time, the corresponding target cells will migrate (Peters et al., 2013). The role of cytokines and their receptors is thought to be important to the pathogenesis of the disease. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study is to explore the effect of narrow band ultraviolet B (NB-UVB) on the chemokine receptor CCR6 mRNA levels in patients with psoriasis. Psoriasis area and severity index (PASI) values were recorded before and after the treatment with NB-UVB phototherapy of 30 psoriasis vulgaris patients. The reverse transcription-polymerase chain reaction method was used to detect the expression level of CCR6 mRNA in peripheral blood mononuclear cells, and compared with 30 healthy subjects. The PASI value of the 30 psoriasis vulgaris patients decreased significantly after 15 iterations of phototherapy treatment (P < 0.01). The expression level of CCR6 mRNA in psoriasis patients was significantly higher than in the healthy controls (P < 0.01), while the expression level of CCR6 mRNA decreased significantly after phototherapy (P < 0.01). Reduction of CCR6 level may be one of the mechanisms through which NB-UVB can treat psoriasis.
    Preview · Article · Oct 2015 · Genetics and molecular research: GMR
  • Source
    • "While increased number of Th17 cells or elevated levels of IL-17A have been reported by many investigators in the peripheral blood [12], [13], bronchoalveolar lavage fluid [14] and the dermis of SSc individuals [15], the available data in humans do not unanimously point to a clear pro-fibrotic role of IL-17A (reviewed in [16]). In the one hand, IL-17A has been shown to enhance dermal fibroblast proliferation, ICAM expression, IL-6, IL-8, monocyte chemoattractant protein (MCP)-1 and matrix metalloproteinase (MMP)-1 production [17]–[22]. In the other hand, IL-17A has been reported to inhibit collagen production and alpha-smooth muscle actin expression induced by transforming growth factor (TGF)-β [15], [23]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background High interleukin (IL)-17A levels are characteristically found in the skin of systemic sclerosis (SSc) individuals. Our aim was to investigate whether the dermal expression of IL-17A and related IL-17 family members (i.e. IL-17C, IL-17E and IL-17F) could distinguish fibrotic from healthy skin and could show similarities in SSc and morphea, two disorders with presumed distinct pathogenesis, but characterized by skin fibrosis. Methods Biopsies were obtained from the involved skin of 14 SSc, 5 morphea and 8 healthy donors (HD) undergoing plastic surgery. Immunohistochemistry/immunofluorescence techniques were coupled to a semi-automated imaging quantification approach to determine the presence of the IL-17 family members in the skin. The in vitro effects induced by the IL-17 family members on fibroblasts from normal and SSc individuals were assessed by ELISA and RIA. Results Positive cells for each of the IL-17 isoforms investigated were present in the dermis of all the individuals tested, though with variable frequencies. SSc individuals had increased frequency of IL-17A+ (p = 0.0237) and decreased frequency of IL-17F+ (p = 0.0127) and IL-17C+ cells (p = 0.0008) when compared to HD. Similarly, morphea individuals had less frequent IL-17C+ cells (p = 0.0186) in their skin but showed similar number of IL-17A+ and IL-17F+ cells when compared to HD. Finally, IL-17E+ cells were more numerous in morphea (p = 0.0109) and tended to be more frequent in SSc than in HD. Fibroblast production of IL-6, MMP-1 and MCP-1 was enhanced in a dose-dependent manner in the presence of IL-17E and IL-17F, but not in the presence of IL-17C. None of the cytokine tested had significant effect on type I collagen production. Of interest, in SSc the frequency of both IL-17A and IL-17F positive cells increased with disease duration. Conclusions The frequency of IL-17A and IL-17F distinguish SSc to morphea individuals while dermal expression of IL-17C (low) and IL-17E (high) identifies a fibrosis-specific motif. The specific IL-17C/IL-17E cytokine combination may thus play a role in the development of fibrosis.
    Full-text · Article · Aug 2014 · PLoS ONE
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Fibroblasts, which are traditionally recognized as a quiescent cell responsible for extracellular matrix production, are more and more appreciated as an active key player of the immune system. This review describes how fibroblasts and immune cells reciprocally influence the pathogenesis of fibrosis. An overview is given how fibroblasts are triggered by components of the innate and adaptive immunity on the one hand and how fibroblasts modulate immune cell behaviour via conditioning the cellular and cytokine microenvironment on the other hand. Finally, latest insights into the role of cardiac fibroblasts in the orchestration of inflammatory cell infiltration in the heart, and their impact on heart failure, are outlined.
    Preview · Article · Apr 2014 · Cardiovascular Research
Show more