Báo cáo khoa học: FGF-2, IL-1b and TGF-b regulate fibroblast expression of S100A8

FGF-2, IL-1ẞ and TGF-β regulate fibroblast expression of S100A8

Tác giả: Farid Rahimi, Kenneth Hsu, Yasumi Endoh and Carolyn L. Geczy

Lĩnh vực: Inflammatory Diseases Research Unit, School of Medical Sciences, University of New South Wales, Sydney, Australia

Nội dung tài liệu: Nghiên cứu này khám phá vai trò của các yếu tố tăng trưởng (FGF-2, TGF-β) và cytokine (IL-1β) trong việc điều hòa biểu hiện của gen S100A8 ở nguyên bào sợi. Kết quả cho thấy FGF-2 và IL-1β có khả năng cảm ứng mạnh mẽ biểu hiện mRNA của S100A8, trong khi TGF-β lại có tác dụng ức chế, đặc biệt là đối với cảm ứng do FGF-2 gây ra. Sự tương tác phức tạp giữa các yếu tố này và vai trò của chúng trong các quá trình như làm lành vết thương và phản ứng viêm cũng được đề cập.

Mục lục chi tiết:

• Keywords
• Correspondence
• Growth factors, including fibroblast growth factor-2 (FGF-2) and transforming growth factor-ẞ (TGF-β) regulate fibroblast function, differentiation and proliferation. S100A8 and S100A9 are members of the S100 family of Ca2+-binding proteins and are now accepted as markers of inflammation. They are expressed by keratinocytes and inflammatory cells in human/murine wounds and by appropriately activated macrophages, endothelial cells, epithelial cells and keratinocytes in vitro. In this study, regulation and expression of S100A8 and S100A9 were examined in fibroblasts. Endotoxin (LPS), interferon γ (IFNγ), tumour-necrosis factor (TNF) and TGF-ẞ did not induce the S100A8 gene in murine fibroblasts whereas FGF-2 induced mRNA maximally after 12 h. The FGF-2 response was strongly enhanced and prolonged by heparin. Interleukin-1ẞ (IL-1ẞ) alone, or in synergy with FGF-2/heparin strongly induced the gene in 3T3 fibroblasts. S100A9 mRNA was not induced under any condition. Induction of S100A8 in the absence of S100A9 was confirmed in primary fibroblasts. S100A8 mRNA induction by FGF-2 and IL-1ẞ was partially dependent on the mitogen-activated-protein-kinase pathway and dependent on new protein synthesis. FGF-2-responsive elements were distinct from the IL-1ẞ-responsive elements in the S100A8 gene promoter. FGF-2-/heparin-induced, but not IL-1ẞ-induced responses were significantly suppressed by TGF-ẞ, possibly mediated by decreased mRNA stability. S100A8 in activated fibroblasts was mainly intracytoplasmic. Rat dermal wounds contained numerous S100A8-positive fibroblast-like cells 2 and 4 days post injury; numbers declined by 7 days. Up-regulation of S100A8 by FGF-2/IL-1ß, down-regulation by TGF-ẞ, and its time-dependent expression in wound fibroblasts suggest a role in fibroblast differentiation at sites of inflammation and repair.
• Fibroblasts are heterogeneous stromal resident cells that participate in wound healing, fibrosis/scarring and immune/inflammatory processes [1,2] by contributing to leukocyte recruitment/accumulation, angiogenesis, matrix metabolism, and protection against oxidative damage [3,4]. Numerous factors including extracellular matrix (ECM) components, some cytokines, prostaglandins, reactive oxygen species (ROS), and growth factors [5] modulate fibroblast function.
• Abbreviations
• Results
• FGF-2 induces S100A8 mRNA in 3T3 fibroblasts
• Kinetics of induction of S100A8 mRNA in 3T3 fibroblasts
• IL-1ẞ-stimulated 3T3 fibroblasts express S100A8 mRNA
• Induction of S100A8 mRNA in primary murine fibroblast-like cells
• Promoter analysis in 3T3 fibroblasts
• The MAPK pathway is involved in S100A8 mRNA induction by FGF-2 and IL-1ẞ in 3T3 fibroblasts
• TGF-ẞ suppresses FGF-2-induced mS100A8 mRNA in 3T3 and primary fibroblasts
• S100A8 protein in activated 3T3 fibroblasts
• S100A8 expression in rat dermal wounds
• Discussion
• Experimental procedures
• Reagents
• Isolation of primary cells, and cell culture
• RNA extraction and Northern analysis
• Reporter assays
• Protein purification and Western blotting
• Protein localization
• Acknowledgements
• References