MicroRNA-21 promotes the progression of peritoneal fibrosis through the activation of the TGF-β/Smad signaling pathway: An in vitro and in vivo study
Authors: Jun Shi
Fang Chen
Su-Xia Yang
Ya-Li Ma
Bao-Ping Chen
Journal: International journal of molecular medicine (2018)
Discipline: CLINICAL MEDICINE
Keywords: microRNA-21; TGF-β; Smad signaling pathway; peritoneal fibrosis; dialysis effluents
Affiliations: Department of Nephrology, Huaihe Hospital of Henan University, Kaifeng, Henan 475000, P.R. China

Abstract:  The present study aimed to explore the roles of microRNA-21 (miR‑21) and the transforming growth factor-β (TGF-β)/Smad signaling pathway in the development of peritoneal fibrosis (PF). First, dialysis effluents from 30 patients with PF were collected, and after the establishment of a mouse model of PF, hematoxylin and eosin (H&amp;E) and Masson's staining were used to observe peritoneal tissues, inflammatory cells and blood vessels. High glucose was used to stimulate human peritoneal mesothelial cell lines and these stimulated cells were then transfected with miR‑21 inhibitor. Immunofluorescence microscopy was applied for the observation of the transfected cells. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of miR‑21, and RT-qPCR and western blot analysis were used to detect the mRNA and protein expression of Zonula occludens-1 (ZO-1), TGF-β, Smad, vimentin and connective-tissue growth factor (CTGF). The mRNA and protein expression levels TGF-β, Smad-3, vimentin and CTGF were elevated, while ZO-1 mRNA and protein expression was decreased with the prolonged duration of dialysis treatment in the patients with PF. The experiments using the mouse model of PF revealed that the peritoneal connective tissue was thickened, while the numbers of inflammatory cells and blood vessels were increased. The expression levels of miR‑21, and the mRNA and protein expression levels of TGF-β, Smad-3, vimentin and CTGF were increased over time, whereas the mRNA and protein expression levels ZO-1 constantly decreased in the mice in the experimental group. Moreoever, the expression of miR‑21 positively correlated with the expression levels of TGF-β, Smad-3, vimentin and CTGF, while it negatively correlated with the expression of ZO-1. The results of H&amp;E and Masson's staining revealed that miR‑21 expression was associated with the degree of PF. These findings thus indicate that miR‑21 promotes the progression of PF through the activation of the TGF-β/Smad signaling pathway. 

Retracted: Yes

PubPeer comments:
 2020 retraction. https: www.ncbi.nlm.nih.gov pubmed 32323729 Int J Mol Med. 2020 Feb 21. doi: 10.3892 ijmm.2020.4510. [Epub ahead of print] [Retracted] MicroRNAu201121 promotes the progression of peritoneal fibrosis through the activation of the TGFu2011u03b2 Smad signaling pathway: An in vitro and in vivo study. Ma YL1, Chen F1, Yang SX1, Chen BP1, Shi J1. Author information 1 Department of Nephrology, Huaihe Hospital of Henan University, Kaifeng, Henan 475000, P.R. China. , 
 #1  An interested reader drew to our attention the fact that the western blots featured in Fig. 2B in the above article contained duplicated data: The data shown for the TGFu2011u03b2 and vimentin protein bands were apparently identical; furthermore, there was a strong likelihood that the protein bands featured for the ZOu20111 and SMADu20113 experiments were also the same, but flipped horizontally relative to the other. Following an investigation, the Journal was able to confirm that this duplication of the research data had probably occurred. On those grounds, the Editor of *International Journal of Molecular Medicine* has decided that the above paper should be retracted. We were unable to make contact with the authors of the article published in *International Journal of Molecular Medicine*, despite every effort to do so. The Editor deeply regrets any inconvenience that this retraction has caused to the the readership of the Journal. Those were perhaps the least of the paper s problems. Here, Fig 9,  positive cells in peritoneal fibrosis observed under a fluorescence microscope [(A) blank group; (B) high glucose group; (C) high glucose + miR-21 inhibitor group; (D) high glucose + miR-21 inhibitor control group]. At right, a 180-deg flipped copy of (A), highlighting the unexpected similarities with (B). ![] ,