Akt blockade downregulates collagen and upregulates MMP1 in human dermal fibroblasts

Area of Science:

• Molecular Biology
• Cell Biology
• Dermatology

Background:

• The Akt (protein kinase B) signaling pathway is crucial for cell survival, proliferation, and has been linked to collagen regulation.
• Systemic sclerosis (SSc) is characterized by excessive collagen deposition in the skin, leading to fibrosis.

Purpose of the Study:

• To investigate the role of Akt in regulating type I collagen production in normal dermal fibroblasts.
• To assess the sensitivity of SSc fibroblasts to Akt inhibition regarding collagen and matrix metalloproteinase 1 (MMP1) production.

Main Methods:

• Utilized pharmacological Akt inhibitors, small interfering RNA (siRNA), and a dominant-negative Akt mutant to block Akt activity.
• Measured type I collagen and MMP1 production in cultured human dermal fibroblasts and SSc fibroblasts.
• Assessed the effect of Akt inhibition on basal and transforming growth factor-beta (TGF-beta)-induced MMP1 gene expression.

Main Results:

• Pharmacological and genetic blockade of Akt significantly inhibited basal type I collagen production in normal dermal fibroblasts.
• Akt inhibition led to increased basal matrix metalloproteinase 1 (MMP1) production and reversed TGF-beta-mediated suppression of MMP1.
• Fibroblasts from SSc patients exhibited heightened sensitivity to Akt inhibition concerning both collagen and MMP1 production.

Conclusions:

• Akt signaling exerts dual profibrotic effects in human dermal fibroblasts by promoting collagen synthesis and suppressing collagen degradation through MMP1 downregulation.
• Akt activation may directly contribute to the elevated collagen levels observed in SSc.
• Targeting the Akt pathway presents a promising therapeutic strategy for managing fibrosis in systemic sclerosis.