Search

Systemic sclerosis (SSc) is an autoimmune connective tissue disease with a triad of features that include vascular abnormalities, inflammation and skin and lung fibrosis. At the core of the disease is the activation of myofibroblasts from quiescent fibroblasts and this can be modified by various cytokines. IL-41 is a recently described cytokine that was initially characterised as an adipokine as it was highly expressed in adipocytes and adipose tissue. However, it has recently been identified as being widely expressed and has immunomodulatory functions. This study examined the circulating levels of IL-41 and its expression in skin biopsies. We demonstrated significantly reduced levels of IL-41 in diffuse SSc that was also mirrored in the skin of SSc patients. AMPK has been proposed as a downstream target of IL-41, so we also measure mammalian target of rapamycin in skin and found that this is elevated in SSc patients. We speculate that IL-41 maybe an antifibrotic cytokine and its reduction may facilitate the activation of fibroblasts. [ABSTRACT FROM AUTHOR]

Systemic sclerosis is an autoimmune connective tissue disease which is characterised by vascular perturbations, inflammation, and fibrosis. Although huge progress recently into the underlying molecular pathways that are perturbed in the disease, currently no therapy exists that targets the fibrosis element of the disease and consequently there is a huge unmet medical need. Emerging studies reveal new dimensions of complexity, and multiple aberrant pathways have been uncovered that have shed light on disturbed signalling in the disease, primarily in inflammatory pathways that can be targeted with repurposed drugs. Pre-clinical animal models using these inhibitors have yielded proof of concept for targeting these signalling systems and progressing to clinical trials. This review will examine the recent evidence of new perturbed pathways in SSc and how these can be targeted with new or repurposed drugs to target a currently intractable disease. [ABSTRACT FROM AUTHOR]

Summary: Interleukin-11 is a cytokine from the IL-6 family of cytokines that includes IL-6 and oncostatin-M. Initially described for its role in platelet generation, it is now appreciated that this cytokine has multiple functions. Recently it has been found that IL-11 is critical in fibrosis in multiple different organ systems and systemically as in the autoimmune disease systemic sclerosis. Animal models of fibrosis have determined that animals with IL-11 receptor deletions have retarded fibrosis and that in wild-type animals IL-11 is found at the organ of fibrosis. Recent evidence suggests that IL-11 may be a master regulator of fibrosis regardless of end target organ. With the development of neutralizing antibodies targeting the cytokine in pre-clinical models this could be a possible therapeutic, in a disease in which no specific therapies exist. This review appraises the evidence of the role of IL-11 in tissue fibrosis, its signalling properties, and therapeutic targeting. The review ends with an appraisal of indications for which IL-11 modulation is targeted. IL-11 is a key IL-6 family cytokine that has recently been associated with tissue fibrosis. [ABSTRACT FROM AUTHOR]

Systemic sclerosis (SSc) is an autoimmune connective tissue disease in which there is elevated inflammation, aberrant cytokine expression, and subsequent fibrosis. Interleukin‐11 (IL‐11) is a recently described profibrotic cytokine that can mediate fibrosis in the heart, lungs, and skin and is upregulated by transforming Growth Factor‐β (TGF‐β1). The objective of this study was to quantify the serum levels of IL‐11 in early diffuse SSc patients. Also, if IL‐11 could regulate the alarmin IL‐33 in dermal fibroblasts was quantified. Early diffuse SSc patient sera was isolated and IL‐11 was quantified by specific commercial ELISA compared to healthy control (n = 17). Healthy dermal fibroblasts were cultured in vitro and then serum starved and incubated with or without recombinant IL‐11. At specific early and late time points the supernatant was quantified for the alarmin IL‐33 by specific ELISA. In early diffuse SSc patients it was demonstrated that they have elevated IL‐11 in their sera. In a subgroup of SSc patients with interstitial lung disease (ILD) this elevation was particularly pronounced compared to those devoid of fibrotic lung disease. In vitro incubation of healthy dermal fibroblasts led to a significant induction of IL‐33 cytokine release into the cell media. IL‐11 is a profibrotic cytokine that is elevated in early diffuse SSc and is particularly elevated in those with ILD. This suggests that IL‐11 could be a possible biomarker of ILD in SSc. It was also found that IL‐11 led to release of the cytokine alarmin IL‐33 in fibroblasts at earlier time points but not late time points, suggesting early stimulation elicits an inflammatory response in the local microenvironment but prolonged stimulation leads to fibrosis. [ABSTRACT FROM AUTHOR]

SSc is an autoimmune disease that has features of vascular abnormalities, inflammation and skin and lung fibrosis. Toll-like receptors (TLRs) are sentinel receptors that serve to recognize pathogens or internal danger signals leading to downstream signalling pathways that ultimately lead to inflammation and modification of adaptive immunity. Inflammation and fibrosis appear intricately connected in this disease and TLR ligation on fibroblasts can directly activate these cells to produce copious amounts of collagen, a hallmark of disease. The presence of damage-associated molecular patterns in association with fibrosis has been highlighted. Given their prominent role in disease, this review discusses the evidence of their expression and role in disease pathogenesis and possible therapeutic intervention to mitigate fibrosis. [ABSTRACT FROM AUTHOR]