Curcumin Interferes with TGF- β 1-Induced Fibrosis in NRK-49F Cells by Reversing ADAMTS18 Gene Methylation

Area of Science:

• Molecular Biology
• Cell Biology
• Biochemistry

Background:

• Renal interstitial fibrosis (RIF) is a critical factor in chronic kidney disease progression.
• Understanding the molecular mechanisms underlying RIF is essential for developing effective treatments.
• Curcumin, a natural compound, has shown potential therapeutic effects, but its precise mechanism in RIF remains unclear.

Purpose of the Study:

• To investigate the molecular mechanism of curcumin in regulating renal interstitial fibrosis (RIF) progression.
• To explore the role of ADAM metallopeptidase with thrombospondin type 1 motif 18 (ADAMTS18) methylation in curcumin's effects on RIF.
• To determine if curcumin can modulate ADAMTS18 expression and methylation status in a cellular RIF model.

Main Methods:

• Established a renal interstitial fibrosis (RIF) model using NRK-49F cells treated with transforming growth factor β 1 (TGF-β 1).
• Assessed the effects of varying curcumin concentrations on cell proliferation, cell cycle, apoptosis, and cyclin D1 expression.
• Analyzed ADAMTS18 methylation levels, mRNA and protein expression of ADAMTS18, fibronectin (FN), type I collagen (Col-I), and alpha-smooth muscle actin (α-SMA).
• Utilized a demethylation agent (5-aza-2'-deoxycytidine) and ADAMTS18 knockdown to further elucidate curcumin's mechanism of action.

Main Results:

• TGF-β 1 treatment inhibited cell proliferation, arrested cells in the G1/G0 phase, promoted apoptosis, and reduced cyclin D1 expression.
• Curcumin (30 μmol/L) significantly reversed these TGF-β 1-induced changes.
• Curcumin and the demethylation agent synergistically increased ADAMTS18 expression, reduced its methylation, and decreased extracellular matrix (ECM) deposition.
• ADAMTS18 knockdown exacerbated ECM accumulation, a process reversed by curcumin.

Conclusions:

• Curcumin effectively alleviates renal interstitial fibrosis (RIF) progression in a cellular model.
• Curcumin exerts its protective effects by promoting ADAMTS18 expression and reducing its methylation.
• The findings suggest that inhibiting ADAMTS18 methylation is a key molecular mechanism by which curcumin ameliorates RIF.