Objective:

2

To explore the molecular mechanism by which curcumin affects renal interstitial fibrosis (RIF) progression by regulating ADAM metallopeptidase with thrombospondin type 1 motif 18 (ADAMTS18) methylation.

Methods:

2

NRK-49F cells RIF model were induced with transforming growth factor β1 (TGF-β1). Effects of different concentrations of curcumin (0

10

20

and 30 μmol/L) on cell proliferation

cell cycle

cell apoptosis as well as cyclin D1 expression were analyzed by cell counting kit-8

flow cytometry and Western blot

respectively. ADAMTS18 methylation levels were determined by methylation-specific polymerase chain reaction. ADAMTS18

fibronectin (FN)

type Ⅰ collagen (Col-Ⅰ) and alpha-smooth muscle actin (α-SMA) mRNA and protein expressions were analyzed by real-time PCR (RT-PCR) and Western blot

respectively. Meanwhile

cells were treated with 50 mmol/L 5-aza-2'-deoxycytidine (5-aza-dC

demethylation agent) for 72 h. Effect of curcumin on extracellular matrix (ECM) deposition was evaluated by immunochemical staining and Western blot. NRK-49F cells were transfected with ADAMTS18 small interfering RNA and grouped into a normal control

ADAMTS18-knock-out (KO)

and ADAMTS18-KO+ 30 μmol/L curcumin groups

and whether curcumin can reverse the effect of ADAMTS18 knockdown on RIF was evaluated.

Results:

2

Compared with the control group

TGF-β1 significantly inhibited the proliferation of NRK-49F cells

blocked the G

1

/G

0

phase

promoted cell apoptosis and inhibited cyclin D1 expression (

P

<

0.01). Among the different concentrations of curcumin

30 μmol/L curcumin significantly reversed these processes (

P

<

0.01). Immunochemical staining and Western blot results showed that curcumin significantly inhibited the deposition of FN

Col-Ⅰ and α-SMA (

P

<

0.01). Curcumin and 5-zaz-dC had synergistic effects

promoting ADAMTS18 expression

removing ADAMTS18 methylation

and reducing ECM deposition. ADAMTS18 knockdown promoted ECM accumulation

and curcumin reversed this process (

P

<

0.01).

Conclusion:

2

TGF-β1 induced fibrosis in NRK-49F cells. Curcumin promoted ADAMTS18 expression

reduced ECM accumulation

and alleviated RIF progression by inhibiting ADAMTS18 methylation.