Dai J, Xu M, Zhang X, Niu Q, Hu Y, Li Y, Li S. Bi-directional regulation of TGF-β/Smad pathway by arsenic: A systemic review and meta-analysis of in vivo and in vitro studies.
Life Sci 2019;
220:92-105. [PMID:
30703382 DOI:
10.1016/j.lfs.2019.01.042]
[Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/18/2019] [Accepted: 01/25/2019] [Indexed: 01/30/2023]
Abstract
BACKGROUND
Arsenic exposure can cause fibrosis of organs including the liver, heart and lung. It was reported that TGF-β/Smad pathway played a crucial role in the process of fibrosis. However, the mechanism of arsenic-induced fibrosis through TGF-β/Smad signaling pathway has remained controversial.
OBJECTIVE
A systematic review and meta-analysis was performed to clarify the relationship between arsenic and TGF-β/Smad pathway, providing a theoretical basis of fibrosis process caused by arsenic.
METHODS
A meta-analysis was used to reveal a correlation between arsenic and fibrosis markers of TGF-β/Smad pathway, including 47 articles of both in vivo and in vitro studies. (Standardized Mean Difference) SMD was employed to compare and analyze the combined effects. When I2 > was 50%, random effect model was selected and subgroup analysis was used to explore the source of heterogeneity.
RESULTS
Arsenic exposure up-regulated the expression of TGF-β1, p-Smad2/3, α-SMA, Collagen1/3 and FN. The dose-response relationship showed that low dose (≤5 μmol/L) arsenic exposure up-regulated the expression of TGF-β1, whereas high doses had a tendency to down-regulate that of TGF-β1. Subgroup analysis showed that low or short-term arsenic exposure induced the expression of TGF-β1 and fibrosis markers.
CONCLUSION
The results indicated that arsenic activates the TGF-β/Smad pathway and induced fibrosis. The mechanism is related to the up-regulation of NADPH oxidase and ROS accumulation. However, high-dose arsenic exposure may inhibit this pathway.
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