The Regulation of Human Dermal Fibroblasts by Mast Cells In Vitro

• Author / Creator

  Rodrigues Silva, Josue

• Background: Dermal fibroproliferative disorders are forms of aberrant cutaneous wound healing, which can lead to the formation of hypertrophic scars (HTS). HTS develop after prolonged healing of deep dermal burns and are associated with excessive inflammation. HTS are characterized by exaggerated cell migration, increased fibroblast proliferation, and up-regulated secretion of cytokines and extracellular matrix proteins. Fibroblasts, especially from the deep layers, are involved during the remodeling process and the excessive biosynthesis of extracellular matrix proteins. Mast cells (MC) have been implicated in fibrotic diseases and HTS development as they are present in significantly greater numbers than in normal skin and appear to degranulate and release pro-inflammatory as well as pro-fibrotic mediators in response to injury. Thus, we hypothesized that activated MC regulate dermal fibroblasts and play a significant role in HTS development. Methods: Fibroblasts were isolated from human HTS tissue and site-matched normal skin, and the superficial and deep layers of normal human skin. The fibroblasts were co-cultured with MC (LAD2) with or without stimulation with substance P. Fibroblast proliferation was quantified by cell counting. Collagen production was measured using the 4-hydroxyproline assay. Myofibroblast differentiation was assessed by flow cytometry. Matrix metalloproteinase-1 and 2, and transforming growth factor-beta 1 were quantified by Simple WES. Simple WES and ELISA measured decorin in the fibroblast lysate and cell culture medium. Fibroblast-populated collagen contraction was examined using a collagen lattice assay.Results: Activated MC significantly increased cell proliferation and reduced collagen production in normal skin fibroblasts (NS Fb), as well as superficial and deep dermal fibroblasts (DF). Myofibroblast differentiation was reduced significantly in NS Fb co-cultured with MC. Activated MC significantly lowered decorin expression in the DF. Also, the levels of decorin in the medium of the NS Fb, and in the layered fibroblasts were significantly down-regulated after co-culturing with activated MC. Likewise, activated MC significantly decreased MMP-1 expression in the DF, and lowered MMP-2 in NS Fb. Activated MC significantly decreased DF-populated collagen gel contraction compared to the controls. Conclusions: In this study, activated MC regulated dermal fibroblasts, and exerted an important modulation of DF in vitro. Our results suggest the relation of activated MC and DF may be one of the key components for HTS development.

• Subjects / Keywords

  • Hypertrophic scars
  • Mast cells
  • Fibroblasts

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-56cw-sd95

• License

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