Downregulation of let-7b promotes COL1A1 and COL1A2 expression in dermis and skin fibroblasts during heat wound repair
Authors: Jinyan Liu
Jia Chen
Jianda Zhou
Zhaoqi Yin
Shaohua Wang
Ping Li
Quanyong He
Chengqun Luo
Journal: Molecular Medicine Reports (2016)
Discipline: CLINICAL MEDICINE
Keywords: MicroRNAs; let-7b; thermal injury; gene expression regulation; skin tissue
Affiliations: Department of Plastic Surgery, Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China.

Abstract:  MicroRNAs (miRs), a class of non‑coding RNAs 18‑25 nucleotides in length, generally serve suppressive role in the regulation of gene expression via directly binding to the 3'‑untranslated region (UTR) of their target mRNA. Previous studies have identified several miRs to be involved in thermal injury repair. However, the role of miR let‑7b during the recovery of thermal injury, in addition to the underlying mechanisms, has not previously been studied. In the present study, the expression of let‑7b was observed to be significantly increased in skin tissue shortly following thermal injury, however, gradually reduced during the recovery of thermal injury. Notably, similar findings were observed in heat‑denatured skin fibroblasts. Furthermore, collagen, type I, alpha 1 (COL1A1) and collagen, type I, alpha 2 (COL1A2), which are associated with the synthesis of type I collagen, were identified as two targets of let‑7b in skin fibroblasts. The overexpression of let‑7b was observed to upregulate the protein expression levels of COL1A1 and COL1A2, while knockdown of let‑7b reduced the levels of COL1A1 and COL1A2 in skin fibroblasts. Furthermore, COL1A1 and COL1A2 were significantly downregulated shortly following thermal injury, while gradually upregulated during healing, in heat‑damaged skin tissue and skin fibroblasts, with the expression profiles opposite to that of let‑7b. Taken together, this suggests that the downregulation of let‑7b in heat‑damaged dermis promotes the synthesis of type I collagen and thus aids in burn wound repair. 

Retracted: No

PubPeer comments:
 Figure 5  Western blotting was performed to detect the protein levels of COL1A1 and COL1A2 in heat-damaged skin tissues at different time points following thermal injury . Rotated through 180 deg... ![file] ...for ease of comparison with Fig 4 A B from [Zhou et al (2016)] .  MiR-98 inhibits MMPs expression and epithelial-mesenchymal transition (EMT) in HCC cells. HCC HepG2 and SMMC-7721 cells transfected with miR-98 mimic or scramble miR mimic (miR-NC). Non-transfected HepG2 and SMMC-7721 cells were used as controls. A, B. Western blot was used to examine the protein levels of MMP2 9 . ![file] UPDATE: Another sighting! Fi6 6C from [Liu et al (2017)] . Fig 6C.  Western blot was used to examine the protein levels of SALL4 in normal lung epithelial BEAS-2B cells and human NSCLC cell lines A549, HCC827, H1229, and SKMES-1 (flipped through 180 deg). ![file] , 
 Dear PubPeer, Our paper was accepted for publication in Molecular Medicine Reports on April 13, 2015. The two other s papers were accepted in 2016 and 2017. I don t know why their pictures are as similar as our s. Regards, JIANDA ZHOU ,