Fli1 Is a Negative Regulator of Estrogen Receptor α in Dermal Fibroblasts

Abstract

Estrogen is an important regulator of dermal fibroblast functions, including extracellular matrix (ECM) synthesis. Estrogen mediates its effects through estrogen receptors (ERs), ERα and ERβ; however, regulation of ERs in dermal fibroblasts remains poorly understood. Friend leukemia integration factor 1 (Fli1), a member of the Ets transcription factor family, has been shown to play a pivotal role in regulation of the ECM genes in dermal fibroblasts. The aim of this study was to examine a possible interaction between Fli1 and estrogen pathways, focusing on ERα. We show that treatment of human dermal fibroblasts with transforming growth factor-β (TGF-β) increases ERα protein and mRNA levels. Similarly, ERα expression was increased in response to small interfering RNA (siRNA)-mediated depletion of Fli1, suggesting that Fli1 is a mediator of the TGF-β effects on ERα expression. Accordingly, we showed that Fli1 binds to the most proximal region of the ERα promoter, and dissociates from the promoter upon TGF-β treatment. An inverse correlation between Fli1 and ERα expression levels was confirmed in cultured skin fibroblasts obtained from Fli1+/− mice and in the skin of Fli1+/− mice in vivo. This study supports a role of Fli1 as a negative regulator of the ERα gene in dermal fibroblasts.

Estrogens Induce Rapid Cytoskeleton Re-Organization in Human Dermal Fibroblasts via the Non-Classical Receptor GPR30

“…Furthermore ER protein was undetectable in western blotting experiments. This is in apparent contrast with previous reports that documented the expression of ERs in human skin [ 17 , 38 – 40 ]. ERβ was the main ER expressed in fibroblasts whereas ER was expressed in sebocytes rather than fibroblasts [ 13 ].…”

“…However, besides changes in skin extracellular matrix content, the function of resident cells in the skin are likely influenced by estrogen. Although the role of exogenous estrogens in the integrity of human dermal fibroblasts has not been investigated, changes in fibroblast phenotype have been noted in aging skin [ 17 – 19 ].…”

Drug Repurposing Screening Identifies Novel Compounds That Effectively Inhibit Toxoplasma gondii Growth

“…Expression of these ER isoforms is either undetectable or nominal in the HFFs used for the screen, suggesting that the drug functions in an ER-independent manner ( 31 , 32 ). We tested this by assessing the growth of β-Gal-expressing parasites in tamoxifen-treated MCF7 cells, which express the ER ( 32 ), and in HeLa cells and murine embryonic fibroblasts (MEFs) that, like HFFs, are ER deficient or express the ER at significantly lower levels than MCF7 cells do ( 33 , 34 ). We found that parasite growth in all three cell types was similarly affected by tamoxifen, although the IC 50 in MCF7 cells was slightly lower ( Fig.…”

Blockade of PDGF Receptors by Crenolanib Has Therapeutic Effect in Patient Fibroblasts and in Preclinical Models of Systemic Sclerosis

“…Gene expression levels were determined by quantitative real-time PCR, as described previously (Hattori et al, 2011). mRNA levels were normalized to those of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene.…”

“…Human dermal fibroblasts were lysed and subjected to immunoblotting, as described previously (Hattori et al, 2011). Primary antibodies used (1:1000): phospho-PDGFRα, PDGFRα, phospho-PDGFRβ, PDGFRβ, phospho-ERK1/2, ERK1/2, phospho-Akt, Akt from Cell Signaling (Danvers, MA), Type I collagen from Southern Biotech (Birmingham, AL), CCN2 from Santa Cruz Biotechnology (Dallas, TX), periostin from Abcam (Cambridge, MA) and β-actin from Sigma (St. Louis, MO).…”