Fascin regulates TLR4/PKC-mediated translational activation through miR-155 and miR-125b, which targets the 3' untranslated region of TNF-α mRNA

MiR-125b regulates inflammation in bovine mammary epithelial cells by targeting the NKIRAS2 gene

Mastitis is a complex inflammatory disease caused by pathogenic infection of mammary tissue in dairy cows. The molecular mechanism behind its occurrence, development, and regulation consists of a multi-gene network including microRNA (miRNA). Until now, there is no report on the role of miR-125b in regulating mastitis in dairy cows. This study found that miR-125b expression is significantly decreased in lipopolysaccharide (LPS)-induced MAC-T bovine mammary epithelial cells. Also, its expression is negatively correlated with the expression of NF-κB inhibitor interacting Ras-like 2 (NKIRAS2) gene. MiR-125b target genes were identified using a double luciferase reporter gene assay, which showed that miR-125b can bind to the 3′ untranslated region (3′ UTR) of the NKIRAS2, but not the 3′UTR of the TNF-α induced protein 3 (TNFAIP3). In addition, miR-125b overexpression and silencing were used to investigate the role of miR-125b on inflammation in LPS-induced MAC-T. The results demonstrate that a reduction in miR-125b expression in LPS-induced MAC-T cells increases NKIRAS2 expression, which then reduces NF-κB activity, leading to low expression of the inflammatory factors IL-6 and TNF-α. Ultimately, this reduces the inflammatory response in MAC-T cells. These results indicate that miR-125b is a pro-inflammatory regulator and that its silencing can alleviate bovine mastitis. These findings lay a foundation for elucidating the molecular regulation mechanism of cow mastitis.

Propofol Regulates the TLR4/NF-κB Pathway Through miRNA-155 to Protect Colorectal Cancer Intestinal Barrier

Surgery for colorectal cancer (CRC) can cause damage to the intestinal mucosal barrier and lead to bacterial invasion. This study mainly analyzed whether propofol (PPF) could protect the intestinal mucosal barrier damage caused by CRC surgery, and explored its molecular mechanism. A mouse CRC model was constructed using azomethane and dextran sulfate sodium. During anesthesia, continuous intravenous injection of PPF was used for intervention. The influences of PPF on intestinal mucosal permeability and bacterial invasion were detected. The levels of microRNA (miR)-155, Toll-like receptor 4 (TLR4)/NF-κB in the intestinal mucosa, and the location of miR-155 were detected by fluorescence in situ hybridization (FISH). Mouse macrophages were used to analyze the regulation of miR-155 on the secretion of inflammatory cytokines through the TLR4/NF-κB pathway. PPF treatment promoted the expression of tight junction protein in the intestinal mucosa, protected the intestinal barrier, inhibited the translocation of intestinal bacteria, and increased the level of the beneficial bacterium Lactobacillus on the mucosal surface. In addition, PPF treatment could inhibit the expression of miR-155, TLR4/NF-KB, and reverse inflammatory response. miR-155 was expressed in macrophages of intestinal mucosa tissue. Overexpression of miR-155 promoted the nuclear translocation of NF-κB and the expression of inflammatory cytokines in macrophages. The use of VIPER to inhibit TLR4 reversed the pro-inflammatory effects of miR-155. PPF might inhibit the activation of the NF-κB pathway by downregulating miR-155 expression, thereby reducing the secretion of inflammatory cytokines. This might be the mechanism by which PPF protected the intestinal barrier of CRC surgical model mice.

Implication of the p53-Related miR-34c, -125b, and -203 in the Osteoblastic Differentiation and the Malignant Transformation of Bone Sarcomas

The formation of the skeleton occurs throughout the lives of vertebrates and is achieved through the balanced activities of two kinds of specialized bone cells: the bone-forming osteoblasts and the bone-resorbing osteoclasts. Impairment in the remodeling processes dramatically hampers the proper healing of fractures and can also result in malignant bone diseases such as osteosarcoma. MicroRNAs (miRNAs) are a class of small non-coding single-strand RNAs implicated in the control of various cellular activities such as proliferation, differentiation, and apoptosis. Their post-transcriptional regulatory role confers on them inhibitory functions toward specific target mRNAs. As miRNAs are involved in the differentiation program of precursor cells, it is now well established that this class of molecules also influences bone formation by affecting osteoblastic differentiation and the fate of osteoblasts. In response to various cell signals, the tumor-suppressor protein p53 activates a huge range of genes, whose miRNAs promote genomic-integrity maintenance, cell-cycle arrest, cell senescence, and apoptosis. Here, we review the role of three p53-related miRNAs, miR-34c, -125b, and -203, in the bone-remodeling context and, in particular, in osteoblastic differentiation. The second aim of this study is to deal with the potential implication of these miRNAs in osteosarcoma development and progression.

MicroRNA-125b regulates Th17/Treg cell differentiation and is associated with juvenile idiopathic arthritis

BACKGROUND

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood driven by aberrant pathways of T-cell activation. T helper 17 (Th17)/regulatory T cell (Treg) imbalance plays critical roles in the pathogenesis of arthritis. MicroRNA-125b (miR-125b) was upregulated after the activation of the initial CD4⁺ T cells, and could regulate the differentiation of CD4⁺ T cells. However, the effects of miR-125b on Th17/Treg imbalance and differentiation of Th17/Treg cells remain unknown.

METHODS

In this study, we evaluated the expression of miR-125b in the peripheral blood mononuclear cells (PBMCs) of children with JIA, and the relationship of miR-125b with Th17/Treg imbalance. Then, we used lentivirus vector-mediated overexpression technology to investigate the regulatory function of miR-125b in CD4⁺ T cells or dendritic cell/CD4⁺ T co-culture system.

RESULTS

Decreased miR-125b expression in PBMCs and CD4⁺ T cells of JIA patients was negatively correlated with the ratio of Th17/Treg cells. It also correlated negatively with retinoic acid receptor-related orphan receptor γt but positively with Forkhead box protein 3 at transcriptional levels. Furthermore, we found that miR-125b overexpression inhibited Th17 cell differentiation, whereas facilitated the differentiation of Treg cells. MiR-125b upregulation led to the decrease of Th17-secreting cytokines but the increase of the Treg-secreting cytokines.

CONCLUSIONS

Our results demonstrate that miR-125b participated in regulating Th17/Treg cell differentiation and imbalance in JIA patients. These findings provide novel insight into the critical role of miR-125b in the Th17/Treg imbalance of JIA, and raise the distinct possibility that miR-125b may prove to be a potential therapeutic target for JIA.

Anemia Severity in β-Thalassemia Correlates with Elevated Levels of microRNA-125b in Activated Phagocytic Monocytes

β-Thalassemia (β-thal), is an inherited blood disorder caused by reduced or absent synthesis of β-globin chains leading to imbalance of globin chain synthesis. The clearance of β-thalassemic abnormal red blood cells (RBCs) that result from excessive unbound α-globin is mainly achieved by activated monocytes. The phagocytic activity of β-thal monocytes significantly increases when co-cultured with normal and β-thal RBC individuals compare to that of normal monocytes co-cultured with normal RBCs. The present study indicates that microRNA (miR) plays a role in monocyte activation. In this study, we identified the higher miR-125b expression in CD14 marker-positive monocytic cells of β-thal patients. Moreover, miR-125b expression levels positively correlate with the phagocytic activity of monocytes. Remarkably, miR-125b expression levels are negatively correlated with RBC count, hemoglobin (Hb) and hematocrit [or packed cell volume (PCV)], which are the indices for the severity of anemia. From these findings, our future studies will be to prove the hypothesis that miR-125b expression in activated monocytes may be a genetic modifier related to the severity of anemia in β-thal patients.

miR-155 Aggravates Liver Ischemia/reperfusion Injury by Suppressing SOCS1 in Mice

Liver ischemia/reperfusion injury (IRI) occurs during partial liver resection and liver transplantation. Activation of Toll-like receptors (TLRs) is a key event triggered by a range of proinflammatory cytokines during liver I/R. Although it has been reported that miR-155 takes part in both innate and adaptive immune responses, the potential role of miR-155 in liver IRI remains unknown. In this study, we found that expression of miR-155 was upregulated during liver I/R by many inflammatory cytokines, and forced expression of miR-155 aggravated hepatocyte injury following liver I/R both in vivo and in vitro. Mice transfected with Ago-miR-155-a chemically modified miR-155-showed enhanced liver severity compared to those transfected with negative control miRNA by inhibiting the expression of SOCS1, the target of miR-155. Thus by the inhibition of SOCS1, the overexpression of miR-155 promoted activation of NF-κB, and elevating the production of proinflammatory cytokines, such TNF-α and IL-6. In conclusion, miR-155 aggravates liver I/R injury in vivo and hepatocyte hypoxia/reoxygenation injury by suppressing the expression of SOCS1.

Fascin2 regulates cisplatin-induced apoptosis in NRK-52E cells

Previous studies have shown that the aging kidney has a marked loss of α(E)-catenin in proximal tubular epithelium. α-Catenin, a key regulator of the actin cytoskeleton, interacts with a variety of actin-binding proteins. Cisplatin-induced loss of fascin2, an actin bundling protein, was observed in cells with a stable knockdown of α(E)-catenin (C2 cells), as well as in aging (24 mon), but not young (4 mon), kidney. Fascin2 co-localized with α-catenin and the actin cytoskeleton in NRK-52E cells. Knockdown of fascin2 increased the susceptibility of tubular epithelial cells to cisplatin-induced injury. Overexpression of fascin2 in C2 cells restored actin stress fibers and attenuated the increased sensitivity of C2 cells to cisplatin-induced apoptosis. Interestingly, fascin2 overexpression attenuated cisplatin-induced mitochondrial dysfunction and oxidative stress in C2 cells. These data demonstrate that fascin2, a putative target of α(E)-catenin, may play important role in preventing cisplatin-induced acute kidney injury.