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Isolation, Culture, and Characterization of Primary Dermal Fibroblasts from Human Keloid Tissue
04:41

Isolation, Culture, and Characterization of Primary Dermal Fibroblasts from Human Keloid Tissue

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Epidermal growth factor protects fibroblasts from apoptosis via PI3 kinase and Rac signaling pathways

Hanshuang Shao1, Xiao-Ming Yi, Alan Wells

  • 1Department of Pathology, University of Pittsburgh, and Department of Pathology, Pittsburgh VAMC, Pittsburgh, Pennsylvania 15261, USA.

Wound Repair and Regeneration : Official Publication of the Wound Healing Society [And] the European Tissue Repair Society
|July 22, 2008
PubMed

Insights

Epidermal growth factor (EGF) prevents fibroblast apoptosis by inhibiting caspase-3 activation via PI3K and Rac signaling pathways. This discovery sheds light on wound repair mechanisms and growth factor-mediated cell survival.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Wound Healing Research

Background:

  • Fibroblast apoptosis is crucial for resolving fibroplasia during wound repair.
  • The molecular mechanisms underlying fibroblast death and growth factor-mediated survival are not fully understood.

Purpose of the Study:

  • To investigate the molecular mechanisms by which epidermal growth factor (EGF) prevents staurosporine-induced apoptosis in fibroblasts.
  • To identify the specific signaling pathways involved in EGF-mediated fibroblast survival.

Main Methods:

  • Utilized a staurosporine-induced apoptosis model in NR6WT fibroblasts expressing human EGF receptors.
  • Examined the role of PI3K, Rac, Akt, and extracellular signal-regulated kinase (ERK) signaling pathways.
  • Employed specific inhibitors, including KP372-1 (Akt inhibitor), and cycloheximide.

Main Results:

  • EGF stimulation blocked staurosporine-induced apoptosis by inhibiting caspase-3 activation.
  • EGF-mediated survival involved PI3K and Rac signaling pathways; simultaneous inhibition abolished the survival effect.
  • Akt signaling pathways downstream of PI3K and Rac were essential for EGF rescue.
  • EGF's protective effect against TNF-α-induced apoptosis involved different pathways than its effect against staurosporine-induced apoptosis.

Conclusions:

  • EGF receptor activation confers a survival response against staurosporine-induced apoptosis via PI3K and Rac signaling.
  • These pathways likely prevent caspase-3 activation, thereby promoting fibroblast survival during wound repair.
  • Identified distinct signaling mechanisms for EGF-mediated survival depending on the apoptotic stimulus.

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