Scleroderma fibroblasts suppress angiogenesis via TGF-β/caveolin-1 dependent secretion of pigment epithelium-derived

Vasiliki Liakouli1,2, Jacobo Elies1,3, Yasser Mohamed El-Sherbiny1,4,5

  • 1Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds, UK.

Abstract

Insights

Transforming growth factor beta (TGF-β) reduces caveolin-1 (Cav-1) in systemic sclerosis (SSc), increasing pigment epithelium-derived factor (PEDF) and inhibiting blood vessel formation. Silencing PEDF restores normal angiogenesis in SSc.

Area of Science:

  • Cell Biology
  • Vascular Biology
  • Fibrosis Research

Background:

  • Systemic sclerosis (SSc) involves tissue fibrosis and impaired blood vessel formation (angiogenesis).
  • Transforming growth factor beta (TGF-β) is implicated in fibrosis and may affect angiogenesis by altering caveolin-1 (Cav-1) expression.
  • Pigment epithelium-derived factor (PEDF), a known antiangiogenic factor, is highly secreted by SSc fibroblasts, suggesting a role in defective angiogenesis.

Purpose of the Study:

  • To investigate the impact of TGF-β and Cav-1 on PEDF expression in SSc.
  • To determine the role of PEDF in the angiogenic capacity of SSc fibroblasts.
  • To elucidate the molecular mechanisms underlying TGF-β-mediated suppression of angiogenesis in SSc.

Main Methods:

  • Immunohistochemistry was used to assess PEDF and Cav-1 expression in human and mouse skin biopsies.
  • Short-hairpin RNAs were employed to silence PEDF and Cav-1 in cultured SSc and control fibroblasts.
  • Organotypic co-cultures and matrigel assays were utilized to evaluate angiogenesis in vitro and in vivo.

Main Results:

  • SSc fibroblasts exhibit high PEDF and low Cav-1 expression, a pattern induced by TGF-β in vitro.
  • SSc fibroblasts demonstrated suppressed angiogenesis, which was replicated by silencing Cav-1 in normal fibroblasts.
  • Silencing PEDF in SSc fibroblasts reversed their antiangiogenic phenotype, and TGF-β-overactivated mice showed reduced vascularity with altered Cav-1 and PEDF levels.

Conclusions:

  • TGF-β suppresses angiogenesis in SSc by decreasing fibroblast Cav-1 expression, leading to increased PEDF secretion.
  • This newly identified pathway represents a potential therapeutic target for treating SSc-related vascular complications.
  • Targeting the TGF-β/Cav-1/PEDF axis may offer novel treatment strategies for systemic sclerosis.

Related Concept Videos

Regulation of Angiogenesis and Blood Supply01:24

Regulation of Angiogenesis and Blood Supply

Rapidly dividing tumors, embryos, and wounded tissues require more oxygen than usual, lowering the oxygen concentration in the blood. At low oxygen or hypoxic conditions, an oxygen-sensitive transcription factor called the hypoxia-inducible factor 1 or HIF1 is activated. HIF1 is a dimeric protein of alpha (ɑ) and beta (β) subunits.  Under optimal oxygen conditions, HIF1β is present in the nucleus while HIF1ɑ remains in the cytosol. HIF1ɑ is hydroxylated by prolyl...
3.6K
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors...
10.6K
Introduction to Fibroblasts01:09

Introduction to Fibroblasts

Rudolph Virchow discovered spindle-shaped cells called fibroblasts in 1858. Inactive fibroblasts, called fibrocytes, become activated by various stimuli, such as growth factors and inflammatory cytokines. Activated fibroblasts play a crucial role in wound healing, inflammation, formation of new blood vessels, and cancer progression. Uncontrolled activation of fibroblasts results in fibrosis, the excess deposition of fibrous tissue, which can lead to scarring and affect normal organs. This...
4.0K
The Tumor Microenvironment02:17

The Tumor Microenvironment

Every normal cell or tissue is embedded in a complex local environment called stroma, consisting of different cell types, a basal membrane, and blood vessels. As normal cells mutate and develop into cancer cells, their local environment also changes to allow cancer progression. The tumor microenvironment (TME) consists of a complex cellular matrix of stromal cells and the developing tumor. The cross-talk between cancer cells and surrounding stromal cells is critical to disrupt normal tissue...
7.9K