Exploring the Complexities of TGF-β Signaling in Keloids: Beyond the Classical Smad Pathway

Area of Science:

• Dermatology
• Molecular Biology
• Cell Signaling

Background:

• Keloids are benign skin growths caused by excessive fibroblast activity and abnormal extracellular matrix deposition.
• Transforming growth factor-β (TGF-β) is recognized as a key cytokine in keloid pathogenesis.
• Traditional understanding focused on the Smad-dependent pathway for TGF-β signaling in keloids.

Purpose of the Study:

• To comprehensively review the molecular mechanisms of TGF-β signaling in keloids, emphasizing non-Smad pathways.
• To highlight the role of Smad-independent signaling in fibroblast behavior within keloids.
• To explore novel therapeutic strategies targeting these pathways to reduce keloid recurrence.

Main Methods:

• Literature review of studies investigating TGF-β signaling in keloid pathogenesis.
• Analysis of molecular pathways including MAPK, PI3K/Akt, Rho GTPase, Wnt/β-catenin, and JAK/STAT.
• Synthesis of current evidence on non-Smad signaling cascades.

Main Results:

• Non-Smad pathways play a crucial role in keloid fibroblast proliferation, migration, anti-apoptosis, fibrogenesis, and inflammation.
• These pathways transmit signals through rapid intracellular kinase cascades, distinct from direct Smad nuclear translocation.
• Specific non-Smad pathways identified include MAPK, PI3K/Akt, Rho GTPase, Wnt/β-catenin, and JAK/STAT.

Conclusions:

• TGF-β exerts its pro-fibrotic effects in keloids through both Smad-dependent and crucial Smad-independent pathways.
• Targeting these non-Smad molecular hubs offers a promising approach to overcome the limitations of current keloid therapies.
• Precision and combination therapies focused on these pathways could reprogram the fibrotic microenvironment and reduce keloid recurrence.