EGF family ligand-dependent phenotypic modulation of smooth muscle cells through EGF receptor

Y Yamanaka1, K Hayashi, T Komurasaki

  • 1Department of Neuroscience (D13), Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.

Insights

Smooth muscle cell (SMC) phenotypic modulation, linked to SMC diseases, is triggered by Epidermal Growth Factor (EGF) family ligands. These ligands activate the EGF receptor (EGFR), initiating signaling pathways crucial for SMC modulation.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Physiology

Background:

  • Smooth muscle cell (SMC) phenotypic modulation is a key factor in the development and progression of various SMC-related diseases.
  • Understanding the molecular mechanisms driving SMC phenotypic modulation is crucial for therapeutic development.

Purpose of the Study:

  • To investigate the molecular mechanisms by which Epidermal Growth Factor (EGF) family ligands trigger phenotypic modulation in differentiated SMCs.
  • To identify the specific receptors and signaling pathways involved in EGF-induced SMC phenotypic modulation.

Main Methods:

  • Utilized a primary culture system of differentiated SMCs.
  • Investigated the activation of EGF receptor (EGFR) family members by various EGF family ligands.
  • Analyzed the activation of downstream signaling pathways, including extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (p38MAPK).

Main Results:

  • EGFR was solely activated by specific EGF family ligands: EGF, heparin-binding EGF (HB-EGF), transforming growth factor alpha (TGF alpha), epiregulin (ER), and betacellulin (BTC).
  • Activation of EGFR by these ligands induced phenotypic modulation in SMCs.
  • The observed phenotypic modulation was mediated by the coordinated activation of the ERK and p38MAPK signaling pathways.

Conclusions:

  • EGF family ligands and EGFR-mediated signaling pathways play a critical role in the phenotypic modulation of SMCs.
  • Targeting the EGF/EGFR signaling axis presents a potential therapeutic strategy for SMC-related diseases.

Related Concept Videos

Mitogens and the Cell Cycle02:38

Mitogens and the Cell Cycle

Mitogens and their receptors play a crucial role in controlling the progression of the cell cycle. However, the loss of mitogenic control over cell division leads to tumor formation. Therefore, mitogens and mitogen receptors play an important role in cancer research. For instance, the epidermal growth factor (EGF) - a type of mitogen and its transmembrane receptor (EGFR), decides the fate of the cell's proliferation. When EGF binds to EGFR, a member of the ErbB family of tyrosine kinase...
Role of Ephrin-Eph Signalling in Intestinal Stem Cell Renewal01:22

Role of Ephrin-Eph Signalling in Intestinal Stem Cell Renewal

Erythropoietin-producing hepatocellular carcinoma receptor (Eph) and its ligand, Eph receptor-interacting protein (Ephrin) were first discovered in the human carcinoma cell line, hence the name. Ephrin-Eph interaction guides cells to reach their appropriate location in adult tissues. They also play an essential role in the immune system by helping in immune cell migration, adhesion, and activation. Based on their structure and function, Eph is divided into two classes — EphA and EphB.
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 hydroxylase and factor...
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 are of three kinds RI, RII, and RIII. The RI...
Receptor Downregulation in MVBs01:15

Receptor Downregulation in MVBs

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR activation may...
GPCRs Regulate Adenylyl Cylase Activity01:09

GPCRs Regulate Adenylyl Cylase Activity

Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...