Curcumin Modulates NOX Gene Expression and ROS Production via P-Smad3C in TGF-β-Activated Hepatic Stellate Cells
Shahla Asadizade1, Mahdi Hatami1, Samaneh Salehipour Bavarsad1
1Cellular and Molecular Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Background:
Liver fibrosis, associated with hepatic stellate cells (HSCs), occurs when a healthy liver sustains damage, thereby impairing its function. NADPH oxidases (NOXs), specifically isoforms 1, 2, and 4, play a role in reactive oxygen species (ROS) production during hepatic injuries, resulting in fibrosis. Curcumin has shown strong potential in mitigating liver fibrosis. Our research aimed to investigate the effects of curcumin on lowering NOX and ROS levels. This compound was also studied for its effects on NOXs, ROS concentrations through the inhibition of Smad3 phosphorylation in transforming growth factor beta (TGF-β)-activated human HSCs.
Methods:
MTT assay investigated the cytotoxic effects of curcumin on HSCs. The cells were activated by exposure to TGF-β (2 ng/mL) for 24 hours. After activating, the cells were treated with curcumin at 25-150 μM concentrations. After administering curcumin to the cells, we employed RT-PCR and Western blot techniques to evaluate the related gene and protein expression levels. This evaluation was primarily focused on the mRNA expression levels of NOX1, NOX2, NOX4 and phosphorylated Smad3C.
Results:
The mRNA expression level of aforesaid NOXs as well as α-smooth muscle actin (α-SMA), collagen1-α, and ROS levels were significantly reduced following 100 μM curcumin treatment. Furthermore, curcumin significantly decreased the p-Smad3C protein level in TGF-β-activated cells, with fold changes of 3 and 2 observed at 75 and 100 μM, respectively.
Conclusion:
Curcumin decreased the levels of ROS and NOX, as well as the expression of α-SMA and collagen1-α. The primary mechanism for this reduction could be linked to the level of p-Smad3C. Hence, curcumin could serve as an effective therapeutic agent for liver fibrosis.
Insights
Curcumin effectively reduces liver fibrosis by lowering NADPH oxidase (NOX) and reactive oxygen species (ROS) levels. This therapeutic potential is linked to inhibiting Smad3 phosphorylation in hepatic stellate cells (HSCs).
Area of Science:
- Hepatology
- Cell Biology
- Pharmacology
Background:
- Liver fibrosis involves hepatic stellate cells (HSCs) and impaired liver function due to damage.
- NADPH oxidases (NOXs) 1, 2, and 4 contribute to reactive oxygen species (ROS) production during liver injury, promoting fibrosis.
- Curcumin demonstrates potential in mitigating liver fibrosis.
Purpose of the Study:
- To investigate curcumin's effects on reducing NOX and ROS levels in liver fibrosis.
- To examine curcumin's impact on NOX and ROS concentrations via Smad3 phosphorylation inhibition.
- To assess curcumin's therapeutic potential in transforming growth factor beta (TGF-β)-activated human HSCs.
Main Methods:
- Cytotoxic effects of curcumin on HSCs were assessed using MTT assay.
- HSCs were activated with TGF-β and subsequently treated with varying curcumin concentrations (25-150 μM).
- Gene and protein expression levels of NOX1, NOX2, NOX4, phosphorylated Smad3C, α-smooth muscle actin (α-SMA), and collagen1-α were evaluated using RT-PCR and Western blot.
Main Results:
- Curcumin treatment (100 μM) significantly reduced mRNA expression of NOXs, α-SMA, collagen1-α, and ROS levels.
- Curcumin significantly decreased p-Smad3C protein levels in TGF-β-activated HSCs (fold changes of 3 at 75 μM and 2 at 100 μM).
Conclusions:
- Curcumin effectively reduces ROS, NOX, α-SMA, and collagen1-α levels, indicating anti-fibrotic properties.
- The mechanism involves the inhibition of p-Smad3C, suggesting a key role in curcumin's therapeutic effects.
- Curcumin shows promise as an effective therapeutic agent for treating liver fibrosis.
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