[Retracted] MicroRNA­9 limits hepatic fibrosis by suppressing the activation and proliferation of hepatic stellate cells by directly targeting MRP1/ABCC1.

Following the publication of this article, a concerned reader drew to our attention that in Fig. 5C on p. 1704, showing histological images of mouse livers stained with H&E, unexpected areas of similarity were identified in terms of the staining patterns revealed within the data panels themselves. After having conducted an internal investigation, the Editor of Oncology Reports has reached the conclusion that the overlapping portions of data shown in this figure were unlikely to have arisen by coincidence. Therefore, on the grounds of a lack of confidence in the integrity of these data, the Editor has decided that the article should be retracted from the publication. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive any reply. The Editor apologizes to the readership for any inconvenience caused, and thanks the interested reader for drawing this matter to our attention. [Oncology Reports 37: 1698­1706, 2017; DOI: 10.3892/or.2017.5382].

MiR-139-5p inhibits proliferation and promoted apoptosis of human airway smooth muscle cells by downregulating the Brg1 gene.

MicroRNAs have emerged as critical regulators in the pathogenesis of asthma. However, the role of microRNAs in asthma needs to be further elucidated. In this study, we found that miR-139-5p was greatly decreased in airway smooth muscle (ASM) cells from asthmatic humans as well as ASM cells stimulated with cytokines. Overexpression of miR-139-5p markedly suppressed ASM cell proliferation and promoted cell apoptosis, whereas knockdown of miR-139-5p had the opposite effect. Further study verified that Brg1, a chromatin remodeling factor, was upregulated in ASM cells treated with cytokines and acted as a direct target of miR-139-5p. Ectopic expression of Brg1 partially reversed the effect of miR-139-5p on cell proliferation and apoptosis. Moreover, overexpression of Brg1 restored miR-139-5p-induced downregulation of Akt and p70S6K phosphorylation. Together, these data indicate that miR-139-5p may function as a key regulator of ASM cell proliferation and apoptosis, potentially by targeting the Brg1 gene, and thus suggesting a potential role of miR-139-5p in the pathogenesis of asthma.

MicroRNA-9 limits hepatic fibrosis by suppressing the activation and proliferation of hepatic stellate cells by directly targeting MRP1/ABCC1.

Liver fibrosis is a chronic liver disease characterized by the proliferation and activation of hepatic stellate cells (HSCs) and excessive deposition of extracellular matrix (ECM). Research suggests that microRNAs (miRNAs) are a new type of regulator of liver fibrosis. In the present study, we investigated the role of microRNA-9 (miR-9) in the process of liver fibrosis, as well as the underlying mechanism of action. Downregulated levels of miR-9 were found in fibrotic liver tissues and activated HSCs as detected by qRT-PCR; whereas, expression of multidrug resistance­associated protein 1 (MRP1/ABCC1) was upregulated in the fibrotic liver tissues and activated HSCs. CCK-8 and BrdU assays revealed that miR-9 reduced the proliferative ability of the HSCs. In addition, expression levels of ECM-related genes (α-SMA, Col-1 and Timp-1), which are markers of HSC activation, were downregulated by miR-9. Conversely, an miR-9 inhibitor promoted cell proliferation and HSC activation. In addition, a luciferase reporter assay indicated that miR-9 targets the 3'-untranslated region (3'-UTR) of MRP1 and causes a significant decrease in MRP1. miR-9 inhibited the activation of the Hedgehog (Hh) pathway and the expression of MRP1, while this suppression was rescued by the overexpression of MRP1. Finally, a CCl4-induced mouse model of liver fibrosis was used to investigate the effects of miR-9 on liver fibrosis in vivo. The results showed that miR-9 abrogated hepatic fibrosis by suppressing the expression of MRP1 in CCl4-induced liver fibrotic mice. In conclusion, the present study demonstrated that miR-9 suppresses the proliferation and activation of HSCs through the Hh pathway by targeting MRP1, which suggests that miR-9 has therapeutic potential for liver fibrosis.

Protease-activated receptor 4 activation increases the expression of calcitonin gene-related peptide mRNA and protein in dorsal root ganglion neurons.

Accumulating evidence demonstrates that nociceptor activation evokes a rapid change in mRNA and protein levels of calcitonin gene-related peptide (CGRP) in dorsal root ganglion (DRG) neurons. Although the colocalization of CGRP and protease-activated receptor-4 (PAR4), a potent modulator of pain processing and inflammation, was detected in DRG neurons, the role of PAR4 activation in the expression of CGRP has not been investigated. In the present study, the expression of CGRP and activation (phosphorylation) of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in rat DRG neurons were measured by immunofluorescence, real-time PCR, and Western blotting after AYPGKF-NH2 (selective PAR4-activating peptide; PAR4-AP) intraplantar injection or treatment of cultured DRG neurons. The expression of CGRP in cultured DRG neurons was also assessed after treatment with AYPGKF-NH2 with preaddition of PD98059 (an inhibitor for ERK1/2 pathway). Results showed that PAR4-AP intraplantar injection or treatment of cultured DRG neurons evoked significant increases in DRG cells displaying CGRP immunoreactivity and cytoplasmic and nuclear staining for phospho-ERK1/2 (p-ERK1/2). Percentages of total DRG neurons expressing both CGRP and PAR4 or p-ERK1/2 also increased significantly at 2 hr after PAR4-AP treatment. Real-time PCR and Western blotting showed that PAR4-AP treatment significantly increased expression of CGRP mRNA and protein levels in DRG neurons. The PAR4 activation-evoked CGRP expression both at mRNA and at protein levels was significantly inhibited after p-ERK1/2 was inhibited by PD98059. These results provide evidence that activation of PAR4 upregulates the expression of CGRP mRNA and protein levels in DRG neurons via the p-ERK1/2 signal pathway.

Capsaicin up-regulates protease-activated receptor-4 mRNA and protein in primary cultured dorsal root ganglion neurons.

Previous study has shown that there is a functional link between the transient receptor potential vanilloid type 1 (TRPV1) receptor and protease-activated receptor-4 (PAR4) in modulation of inflammation and pain. Capsaicin activation of TRPV1 is involved in enhancement of the expression of TRPV1 in mRNA and protein in dorsal root ganglion (DRG) in vivo. Whether capsaicin could influence expression of PAR4 in primary sensory neurons remains unknown. In the present study, expression of PAR4 in cultured rat DRG neurons was observed using immunofluorescence, real-time PCR and Western blots to examine whether increases in PAR4 mRNA and protein levels are induced by capsaicin treatment with or without pre-treatment of forskolin, a cyclic AMP/protein kinase A (cAMP/PKA) activator or PKA inhibitor fragment 14-22 (PKI14-22), a PKA inhibitor. Capsaicin treatment of cultured DRG neurons significantly increased the expression of PAR4 in mRNA and protein levels. The percentage of PAR4-, TRPV1-immunoreactive neurons and their co-localization in cultured DRG neurons increased significantly in the presence of capsaicin as compared with that in the absence of capsaicin. Compared with capsaicin-only group, pre-incubation with forskolin strongly enhanced the capsaicin-induced increase of PAR4 in mRNA and protein levels. Consistent with the involvement of PKA in the modulation of PAR4 expression, this evoked expression both at mRNA and protein levels was significantly inhibited after PKA was inhibited by pre-incubation with PKI14-22. Taken together, these results provide evidence that TRPV1 activation significantly increases the expression of PAR4 mRNA and protein levels in primary cultures of DRG neurons after capsaicin incubation. Effects of capsaicin on PAR4 expression appear to be mediated by cAMP/PKA signal pathways in DRG neurons.