miRNA‑21 promotes the progression of acute liver failure via the KLF6/autophagy/IL‑23 signaling pathway

Acute liver failure (ALF) is a complex syndrome characterized by overactivation of innate immunity, and the recruitment and differentiation of immune cells at inflammatory sites. The present study aimed to explore the role of microRNA (miRNA/miR)‑21 and its potential mechanisms underlying inflammatory responses in ALF. Baseline serum miR‑21 was analyzed in patients with ALF and healthy controls. In addition, miR‑21 antagomir was injected via the tail vein into C57BL/6 mice, and lipopolysaccharide/D‑galactosamine (LPS/GalN) was injected into mice after 48 h. The expression levels of miR‑21, Krüppel‑like‑factor‑6 (KLF6), autophagy‑related proteins and interleukin (IL)‑23, and hepatic pathology were then assessed in the liver tissue. Furthermore, THP‑1‑derived macrophages were transfected with a miRNA negative control, miR‑21 inhibitor, miR‑21 mimics or KLF6 overexpression plasmid, followed by treatment with or without rapamycin, and the expression levels of miR‑21, KLF6, autophagy‑related proteins and IL‑23 were evaluated. The results revealed that baseline serum miR‑21 levels were significantly upregulated in patients with ALF. In addition, LPS/GalN‑induced ALF was attenuated in the antagomir‑21 mouse group. KLF6 was identified as a target of miR‑21‑5p with one putative seed match site identified by TargetScan. A subsequent luciferase activity assay demonstrated a direct interaction between miR‑21‑5p and the 3'‑UTR of KLF6 mRNA. Further experiments suggested that miR‑21 promoted the expression of IL‑23 via inhibiting KLF6, which regulated autophagy. In conclusion, in the present study, baseline serum miR‑21 levels were highly upregulated in patients with ALF, antagomir‑21 attenuated LPS/GalN‑induced ALF in a mouse model, and miR‑21 could promote the expression of IL‑23 via inhibiting KLF6.

[Retracted] MicroRNA‑21 promotes migration and invasion of glioma cells via activation of Sox2 and β‑catenin signaling

Following the publication of the above paper, a concerned reader drew to the Editor's attention that there were several data panels showing the results of Transwell migration and invasion assay experiments in Figs. 1A and 2A that contained overlapping sections of data, such that these data, which were intended to have shown the results from differently performed experiments, appeared to have been derived from a smaller number of original sources. Furthermore, the data panels shown in Fig. 3A for the 'Control/U343' and 'Control/172', and the 'miR‑21/β‑catenin' and 'Control/T98', experiments were also found to be unexpectedly similar, given that these were likewise intended to show the results from differently performed experiments. After having conducted an independent investigation in the Editorial Office, the Editor of Molecular Medicine Reports has determined that the above paper should be retracted from the Journal on account of a lack of confidence in the presented data. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a satisfactory reply. The Editor regrets any inconvenience that has been caused to the readership of the Journal. [Molecular Medicine Reports 15: 187‑193, 2017; DOI: 10.3892/mmr.2016.5971].

Gypenoside XVII protects against spinal cord injury in mice by regulating the microRNA‑21‑mediated PTEN/AKT/mTOR pathway

Gypenoside XVII (GP‑17), one of the dominant active components of Gynostemma pentaphyllum, has been studied extensively and found to have a variety of pharmacological effects, including neuroprotective properties. However, the neuroprotective effects of GP‑17 against spinal cord injury (SCI), as well as its underlying mechanisms of action remain unknown. The present study aimed to investigate the effects of GP‑17 on motor recovery and histopathological changes following SCI and to elucidate the mechanisms underlying its neuroprotective effects in a mouse model of SCI. Motor recovery was evaluated using the Basso, Beattie and Bresnahan (BBB) locomotor rating scale. Spinal cord edema was detected by the wet/dry weight method. H&E staining was performed to examine the effect of GP‑17 on spinal cord damage. Inflammatory response production was assessed by ELISA. Candidate miRNAs were identified following the integrated analysis of the Gene Expression Omnibus (GEO) dataset GSE67515. Western blot analysis was also performed to detect the expression levels of associated proteins. The results revealed that GP‑17 treatment improved functional recovery, and suppressed neuronal apoptosis and the inflammatory response in the mouse model of SCI. Moreover, it was observed that miR‑21 expression was downregulated following SCI, whereas it was upregulated following the administration of GP‑17. The inhibition of miR‑21 eliminated the protective effects of GP‑17 on SCI‑induced neuronal apoptosis and the inflammatory response. In addition, phosphatase and tensin homologue (PTEN), a key molecule in the activation of the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway, was identified as a target of miR‑21, and PTEN expression was downregulated by GP‑17 through miR‑21. Furthermore, the PTEN/AKT/mTOR pathway was inactivated by SCI, whereas it was re‑activated by GP‑17 through the regulation of miR‑21 in mice with SCI. On the whole, the findings of the present study suggest that GP‑17 plays a protective role in SCI via regulating the miR‑21/PTEN/AKT/mTOR pathway.

Size changes in miR‑21 knockout mice: Geometric morphometrics on teeth, alveolar bone and mandible

MicroRNA‑21 (miR‑21) is a small non‑coding RNA that is differentially expressed during tooth development, particularly during amelogenesis. Although orthodontic tooth movement and the innate immune response are impaired, miR‑21 knockout mice demonstrate no obvious skeletal phenotype. However, the consequence of miR‑21 knockout on tooth phenotype and corresponding alveolar bone is unknown. The current study utilized landmark‑based geometric morphometrics to identify anatomical dissimilarities of the three lower and upper molars, and the corresponding alveolar bone, in miR‑21 knockout and wild‑type control mice. The anatomical structures were visualized by microcomputer tomography. A total of 36 and 38 landmarks were placed on mandibular and maxillary molars, respectively. For the alveolar bone, 16 landmarks were selected on both anatomical sites. General Procrustes analysis revealed significantly smaller molars and dimensions of the alveolar bone in the mandible of the miR‑21 knockout mice when compared with wild‑type controls (P=0.03 and P=0.04, respectively). The overall dimension of the mandible was reduced by the lack of miR‑21 (P=0.02). In the maxilla, the dimension of the alveolar bone was significant (P=0.02); however, this was not observed in the molars (P=0.36). Based on principal component analysis, no changes in shape for any of the anatomical sites were observed. Dental and skeletal jaw length were calculated and no prognathism was identified. However, the fluctuating asymmetry of the molars in the mandible and the maxilla was reduced in the miR‑21 knockout mice by 38 and 27%, respectively. Taken together, the results of the present study revealed that the molars in the mandible and the dimension of the respective alveolar bone were smaller in miR‑21 mice compared with wild‑type littermates, suggesting that miR‑21 influences tooth development.

Dexmedetomidine suppresses the development of abdominal aortic aneurysm by downregulating the mircoRNA‑21/PDCD 4 axis

Abdominal aortic aneurysm (AAA) is a pathological state with permanent dilation, which indicates a fatal potential for aortic rupture. It has been reported that dexmedetomidine (Dex) and microRNA (miR)-21 are involved in the progression of AAA. Thus, the present study aimed to investigate the joint effects of these factors on AAA treatment. For this purpose, rat models of AAA were established with enzyme perfusion and the rats were then injected with Dex. Alterations in the abdominal aorta in rats with AAA were recorded. miR-21 expression in the rats with AAA was determined. Inflammatory factor expression was detected by western blot analysis. Subsequently, a dual-luciferase reporter gene assay was performed to verify the targeting association between miR-21 and programmed cell death protein 4 (PDCD4). Additionally, AAA-related indices and inflammatory responses were examined by an injection of a combination of antagomiR (ant)-miR-21 and Dex or lentivirus-PDCD4-short hairpin RNA. It was found that Dex markedly alleviated the development of AAA and downregulated the expression of inflammatory factors and matrix metalloproteinase in rats with AAA. The high expression of miR-21, which targets PDCD4, was observed in the rats with AAA. However, ant-miR-21 induced AAA development and inflammatory responses. Additionally, the inhibition of PDCD4 reduced AAA development and inflammatory responses. On the whole, the present study demonstrates that Dex inhibits AAA development by downregulating the miR-21/PCDP4 axis. The findings of the present study may provide novel insight for the treatment of AAA. These findings may provide a reference for the future treatment of AAA and may provide theoretical guidance for the early prevention and development of AAA.

Genistein alleviates chronic vascular inflammatory response via the miR‑21/NF‑κB p65 axis in lipopolysaccharide‑treated mice

Chronic vascular inflammatory response is an important pathological basis of cardiovascular disease. Genistein (GEN), a natural compound, exhibits anti‑inflammatory effects. The aim of the present study was to investigate the effects of GEN on lipopolysaccharide (LPS)‑induced chronic vascular inflammatory response in mice and explore the underlying anti‑inflammatory mechanisms. C57BL/6 mice were fed with a high‑fat diet combined with intraperitoneal injection of LPS to induce chronic vascular inflammation. The expression levels of TNF‑α, IL‑6 and microRNA (miR)‑21 in the vasculature were detected via reverse transcription‑quantitative (RT‑q)PCR. The protein levels of inducible nitric oxide synthase (iNOS) and NF‑κB p65 were detected via western blotting. NF‑κB p65 was also analyzed via immunohistochemistry and immunofluorescence (IF). In addition, after transfection with miR‑21 mimic or inhibitor for 24 h, vascular endothelial cells (VECs) were treated with GEN and LPS. RT‑qPCR and western blot analyses were performed to detect the expression of TNF‑α, IL‑6, miR‑21 and iNOS, and the protein levels of iNOS and NF‑κB p65, respectively. IF was used to measure NF‑κB p65 nuclear translocation. The results revealed that GEN significantly decreased the expression of inflammation‑associated vascular factors in LPS‑treated C57BL/6 mice, including TNF‑α, IL‑6, iNOS, NF‑κB p65 and miR‑21. Furthermore, miR‑21 antagomir enhanced the anti‑inflammatory effects of GEN. In LPS‑induced VECs, miR‑21 mimic increased inflammation‑associated factor expression and attenuated the anti‑inflammatory effects of GEN, whereas miR‑21 inhibitor induced opposing effects. Therefore, the results of the present study suggested that GEN inhibited chronic vascular inflammatory response in mice, which may be associated with the inhibition of VEC inflammatory injury via the miR‑21/NF‑κB p65 pathway.