Effects Of microRNA-155 Research Articles

The possible effect of microRNA-155 (miR-155) and BACE1 inhibitors in the memory of patients with down syndrome and Alzheimer's disease: Design, synthesis, virtual screening, molecular modeling and biological evaluations

MiR-155 plays main roles in several physiological and pathological mechanisms, such as Down syndrome (DS), immunity and inflammation and potential anti-AD therapeutic target. The miR-155 is one of the overexpressed miRNAs in DS patients that contribute directly and indirectly to the onset or progression of the DS. Since the miR-155 can simultaneously reduce the translation of several genes at post-transcriptional levels, targeting the miR-155 might set the stage for the treatment of DS. One of the rational strategies in providing therapeutic interventions in this respect is to design and develop novel small molecules inhibiting the miR-155 function or biogenesis or maturation. In the present study, we aim to introduce small molecule compounds with the potential to inhibit the generation of the selectively miR-155 processing by employing computational drug design approaches, as well as in vitro studies. We designed and synthesized a novel series of imidazo[1,2-a]pyridines derivatives as new nonpeptic candidates for the treatment of DS with AD. The designed compounds were investigated for their BACE1 and miR-155 binder inhibitory potential in vitro and in cell. In addition, we present a systematic computational approach that includes 3 D modeling, docking-based virtual screening, and molecular dynamics simulation to identify Small - molecule inhibitors of pre-miR-155 maturation. To confirm the inhibitory potential of compound 8k on miR-155 maturation, qRT- PCR was performed. All our results confirm that compound 8k, in addition to being a good inhibitor of BACE1, can also be a good inhibitor of miR-155. Communicated by Ramaswamy H. Sarma

Effect of microRNA-155 on the invasion and metastasis of human laryngeal epidermoid carcinoma cell in laryngeal squamous cell carcinoma

Effect of microRNA-155 on the invasion and metastasis of human laryngeal epidermoid carcinoma cell in laryngeal squamous cell carcinoma

Effects of microRNA-155 on biological functions of gastric cancer cells and possible mechanism

Objective To discuss the deregulation expression level of microRNA (miRNA, miR)-155 in gastric cancer tissue, and its effect on the gastric cancer cell proliferation and cell biology functions such as proliferation and adhesion. Methods We performed a real-time reverse transcriptase-polymerase chain reaction in 42 cases of gastric cancer and the corresponding cancer adjacent tissues, and quantitatively determined the expression level of the miR-155. At the same time, a variety of experimental methods were used to determine whether the abnormal expression of miR-155 could inhibit or promote the viability, proliferation and invasion of the SGC-7901 cells in gastric cancer. Results As compared with normal tissues and cells, the expression of miR-155 in human gastric cancer tissues and SGC-7901 cells was decreased. The proliferation of miR-155 mimics (29.912±1.786) was significantly lower than that of the control group (34.962±1.413), and the differences were statistically significant. The cell viability test revealed that cells in the 50 nmol/L mimics transfection group (91.34±1.33) and the 100 nmol/L transfection group (84.59±1.63) showed significantly lower survival rate than normal gastric cancer cells (94.39±1.07) (P<0.05). Cell adhesion test showed that the absorbance of miR-155 mimics in each experimental group was 0.861±0.051 (30 nmol/L), 0.738±0.055 (50 nmol/L), 0.665±0.042 (80 nmol/L), 0.531±0.032 (100 nmol/L), significantly lower than that in the control group (1.098±0.054) (P<0.01). Conclusion The abnormal low expression of miR-155 may participate in the development process of gastric cancer, and enhance the vitality of gastric cancer cell proliferation and other biological characteristics to achieve the function as a recessive cancer gene. Key words: Gastric cancer; MicroRNA; MicroRNA-155; Proliferation

Down-regulation of microRNA-155 promotes selenium deficiency-induced apoptosis by tumor necrosis factor receptor superfamily member 1B in the broiler spleen.

The aim of this work was to explore the microRNA profile and the effect of microRNA-155 on apoptosis in the spleen of selenium-deficient broilers. We replicated the splenic-apoptotic model in selenium-deficient broilers. In vitro, microRNA-155 oligonucleotides were transfected into lymphocytes and subsequently treated with H2O2. We observed that selenium deficiency altered the microRNA profile and decreased the expression of microRNA-155 in the broiler spleens. Tumor necrosis factor receptor superfamily member 1B was verified as a target of microRNA-155 in the splenocytes. Morphological changes, increased levels of tumor necrosis factor receptor superfamily member 1B, c-Jun N-terminal kinase, Bak, Bax, Cyt-c, caspase9 and caspase3 and decreased levels of Bcl-2 demonstrated that selenium deficiency induced apoptosis in the spleen tissues. In vitro, microRNA-155 m inhibited the levels of ROS and reduced apoptosis compared with microRNA-155i in the lymphocytes. These results suggested that the reduced levels of microRNA-155 due to selenium deficiency could promote oxidative stress-induced apoptosis by increased tumor necrosis factor receptor superfamily member 1B in splenic cells.

Effect of microRNA-155 on the interferon-gamma signaling pathway in biliary atresia.

MicroRNAs (miRNAs) are ~22-nucleotide long RNAs that negatively regulate gene expression and inflammatory responses in eukaryotes. The aim of this work was to evaluate the roles of miRNA (miR)-155 on the interferon-γ (IFN-γ)-induced response in biliary atresia (BA), which is the most common form of pediatric chronic liver disease and a leading indication for pediatric liver transplantation. The expression of miR-155 and the suppressor of cytokine signaling 1 (SOCS1) gene in human and mice liver tissues of BA and healthy controls was evaluated. IFN-γ-induced expression of miR-155, inflammatory cytokines and chemokines was determined in bile duct cells. A miR-155 inhibitor was used to determine the influence in the IFN-γ-induced signaling pathway by western blot analysis. A strong up-regulation of miR-155 expression was observed in BA histologic sections and mouse bile duct cells treated with IFN-γ. miR-155 down-regulated SOCS1 protein expression by targeting its mRNA. Up-regulation of miR-155 expression by IFN-γ in bile duct cells led to the activation of signal transducers and activators of transcription 1 (Stat1) and inflammatory cytokines through the Janus kinase (Jak)/Stat pathway, whereas targeted inhibition of miR-155 expression by anti-miRNA oligonucleotides significantly decreased the mRNA or protein expression levels of these inflammatory cytokines and Stat1. Overall, our results suggest that miR-155 regulates the IFN-γ signaling pathway by targeting SOCS1 expression and may be a potential target in BA therapy.

The Emerging Role of MicroRNA-155 in Cardiovascular Diseases.

MicroRNAs have been demonstrated to be involved in human diseases, including cardiovascular diseases. Growing evidences suggest that microRNA-155, a typical multifunctional microRNA, plays a crucial role in hematopoietic lineage differentiation, immunity, inflammation, viral infections, and vascular remodeling, which is linked to cardiovascular diseases such as coronary artery disease, abdominal aortic aneurysm, heart failure, and diabetic heart disease. The effects of microRNA-155 in different cell types through different target genes result in different mechanisms in diseases. MicroRNA-155 has been intensively studied in atherosclerosis and coronary artery disease. Contradictory results of microRNA-155 either promoting or preventing the pathophysiological process of atherosclerosis illustrate the complexity of this pleiotropic molecule. Therefore, more comprehensive studies of the underlying mechanisms of microRNA-155 involvement in cardiovascular diseases are required. Furthermore, a recent clinical trial of Miravirsen targeting microRNA-122 sheds light on exploiting microRNA-155 as a novel target to develop effective therapeutic strategies for cardiovascular diseases in the near future.

Effect of microRNA-155 on angiogenesis after cerebral infarction of rats through AT1R/VEGFR2 pathway.

To explore the function and mechanism of microRNA-155 to regulate the angiogenesis after the cerebral infarction of rats through the angiotensin II receptor 1 (AT1R)/vascular endothelial growth factor (VEGF) signaling pathway. Female SD rats were chosen for the construction of cerebral infarction model of rats using the modified right middle cerebral artery occlusion. The real-time PCR (RT-PCR) method was employed to detect the expression of microRNA-155 in each group at different time points after the cerebral infarction (1h, ld, 3d and 7d). SD rats were randomly divided into four groups (n=20 rats): sham operation group (Sham group), MACO group, MACO+microRNA-155 mimic group, and MACO+microRNA-155 inhibitor group. Sham group was given the free graft, while MACO+microRNA-155 mimic group and MACO+microRNA-155 inhibitor group were treated with microRNA-155 mimic and microRNA-155 inhibitor respectively. The Zea Longa 5-point scale was used to score the neurologic impairment of rats in each group; 2, 3, 5-triphenyl tetrazolium chloride staining to evaluate the volume of cerebral infarction of rats in each group; the immunohistochemistry to detect the expression of CD31; Western blot and RT-PCR to detect the expression of AT1R and VEGF receptor 2 (VEGFR2). The expression of microRNA-155 was increased in the cerebral ischemia tissue after the cerebral infarction. It was significantly increased at 1d of ischemia and maintained at the high level for a long time. Rats in the Sham group had no symptom of neurologic impairment, while rats in the MACO group had the obvious neurologic impairment. After being treated with microRNA-155 inhibitor, the neural function of MACO rats had been improved, with the decreased area of cerebral infarction. But after being treated with microRNA-155 mimic, the neural function was further worsened, with the increased area of cerebral infarction. Results of immunohistochemical assay indicated that microRNA-155 inhibitor could up-regulate the expression of CD31, while microRNA-155 mimic could down-regulate the expression of CD31. The RT-PCR found that, after being treated with microRNA-155 inhibitor, MACO rats had the increased expression of AT1R and VEGFR2 messenger RNA (mRNA); but after being treated with microRNA-155 mimic, the expression of AT1R and VEGFR2 mRNA was decreased. Results of Western blot showed that, after being treated with microRNA-155 inhibitor, MACO rats had the increased expression of AT1R and VEGFR2 mRNA; but after being treated with microRNA-155 mimic, the expression of AT1R and VEGFR2 mRNA was decreased. The inhibition of microRNA-155 can improve the neurologic impairment of rats with the cerebral infarction, reduce the volume of cerebral infarction and effectively promote the angiogenesis in the region of ischemia, which may be mediated through AT1R/VEGFR2 pathway.

Effects of microRNA-155 on mice with lipopolysaccharide-induced acute lung injury

To study the effects of microRNA (miR)-155 on mice with acute lung injury induced by lipopolysaccharide (LPS). According to the random number table, 30 C57 mice were divided into group LPS, group miR-155 inhibitor, group miR control, group miR-155 mimics, normal control group, with 6 mice in each group. Mice in group LPS and the other three treatment groups were given 5 µl LPS (20 µg/µl, in the dose of 4 mg/kg) to reproduce acute lung injury model. Half an hour after injury, group LPS, group miR-155 inhibitor, group miR control, group miR-155 mimics were injected with saline, miR-155 inhibitor, miR control and miR-155 mimics through trachea. Mice in normal control group were received no treatment. All mice were anesthetized after 24 h, while lung tissue samples were harvested for histomorphological observation, detection of mRNA expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) with SYBR Green real-time polymerase chain reaction (PCR), detection of miR-155 in group miR-155 inhibitor, group miR control, group miR-155 mimics by Taqman PCR. The protein expression of cyclooxygenase-2 (COX-2) was determined by western blot. Data were statistically analyzed. The relative mRNA expression values of TNF-α were 24.49 ± 3.64, 38.92 ± 3.40, 36.00 ± 3.86, 12.56 ± 2.06, 1.04 ± 0.41 in group LPS, group miR-155 inhibitor, group miR control, group miR-155 mimics, normal control group. The relative mRNA expression values of IL-1β were 55.96 ± 4.87, 62.90 ± 6.41, 59.99 ± 6.48, 25.33 ± 3.50, 1.11 ± 0.44 in group LPS, group miR-155 inhibitor, group miR control, group miR-155 mimics, normal control group. The differences of TNF-α and IL-1β in group miR-155 mimics were statistically significant by compared with group LPS, group miR-155 inhibitor, group miR control (P < 0.05). The differences were not statistically significant among group LPS, group miR-155 inhibitor, group miR control. Western blot analysis showed the relative expression values of COX-2 were 0.94 ± 0.06, 0.96 ± 0.09, 0.91 ± 0.03, 0.79 ± 0.04, 0.63 ± 0.07 in group LPS, group miR-155 inhibitor, group miR control, miR-155 mimics and normal control group. The value in normal control group was significantly lower than other groups (P < 0.05). Using the miR-155 can effectively alleviate the lung inflammation in mice with acute lung injury induced by LPS.

Effects of microRNA-155 on interleukin-1 receptor-associated kinase 1 and 4 mRNA expression in liver injury of endotoximia mice

Objective To explore the protective effect of microRNA (miRNA)-155 inhibitor on interleukin-1 receptor-associated kinase (IRAK)-1 mRNA and IRAK-4 mRNA in endotoximia induced liver injury in mice. Methods One hundred and twenty male BALB/c mice were randomly divided into healthy control group (n=40), endotoximia group (n=40) and miRNA-155 inhibitor group (n=40). Each group were divided into 6 h, 12 h, 24 h, 48 h subgroups, each of which consisted of 10 mice. The mice in miRNA-155 inhibitor group were administered with miRNA-155 inhibitor[80 mg (kg·d)] via tail vein injection before lipopolysaccharide (LPS) administration while the other two groups treated with normal saline, following 24 hours, model of endotoximia mice was produced by injection of LPS intraperitoneally. At 6 h, 12 h, 24 h, 48 h after LPS exposure, the experimental mice were sacrificed and the liver tissue samples were collected. Histopathological changes, the expression of miRNA-155, IRAK-1 mRNA, IRAK-4 mRNA, tumor necrosis factor (TNF)-α, IL-1, IL-10 were detected. Results LPS exposure resulted in increase of miRNA-155, IRAK-1 mRNA, IRAK-4 mRNA, TNF-α, IL-1 and IL-10 in both endotoximia group and miRNA-155 inhibitor group compared to the control group. miRNA-155 inhibitor resulted in decrease of miRNA-155, IRAK-1 mRNA, IRAK-4 mRNA, TNF-α, IL-1 and IL-10 in miRNA-155 inhibitor group compared to the endotoximia group. There were significant differences of miRNA-155 expression at 12 h, 24 h, 48 h after LPS exposure among 3 groups (P<0.05). Both IRAK-1 mRNA and IRAK-4 mRNA showed significant differences at 12 h, 24 h, 48 h. Turning to inflammation factors, differences were found among 3 groups at all time points (P<0.05). At light-scope, there was improvement in sepsis associated liver injury in miRNA-155 inhibitor group compared to endotoximia group. Conclusion miRNA-155 inhibitor administration appears to down regulate IRAK-1 mRNA and IRAK-4 mRNA expression and further deduce the excessive inflammatory and anti-inflammatory reaction, which may alleviate liver injury in endotoximia mice. Key words: MicroRNA-155; Interleukin-1 receptor-associated kinase mRNA; Interleukin-4 receptor-associated kinase mRNA; Liver injury; Endotoxin; RNA interference; Mice

Macrophage Polarization and the Effect of MicroRNA-155 Administered in Water-in-Oil-in-Water Multiple Emulsion Formulations

The tumor microenvironment is composed of range of cells including macrophages that participate in sustaining tumor growth and invasion. Tumor-associated macrophages (TAM’s) polarized to the M2 or pro-tumoral phenotype are one such population of cells highly expressed in the tumor microenvironment. The expression of microRNA’s (miR’s) is often found to be dysregulated in TAM’s and hence exogenous delivery of miR provides a strategy for macrophage phenotypic modulation to attain improved anticancer activity. In this study, we assessed the use of multiple emulsions for the delivery of miR to achieve macrophage M1 repolarization. Water-in-oil-in-water (WOW) multiple emulsions (ME) were prepared using a two-step emulsification technique for encapsulation of miR-155 and cellular uptake, transfection efficiency, and repolarization capability of J774A.1 macrophages was assessed. The repolarized macrophages were co-cultured with SKOV3 ovarian cancer cells to assess the effect on macrophage morphology, motility and apoptosis of cancer cells. The ME showed enhanced uptake and expression of miR-155, which resulted in improved M1 polarization of J774A.1 cells. Co-culture studies with SKOV3 cells indicated an alteration in apoptotic profile. Holographic assessment of the co-cultured cells in real-time showed differences in motility and morphology of macrophages with miR-155 ME treated cells showing greater cellular interaction between the two phenotypes.

Expression and effects of microRNA-155 in the livers of septic mice

To evaluate the effects of microRNA-155 (miR-155) on liver injury in mice with sepsis. One hundred and twenty BALB/c mice were randomly divided into two groups of equal number according to random number table. Sepsis was induced by intraperitoneal injection of lipopolysaccharide (LPS,20 mg/kg). The mice were sacrificed at the time-points of 0, 2, 6, 12, 24, 48 hours. Blood and liver tissue were collected, and the levels of tumor necrosis factor- α (TNF- α ), interleukin (IL-6, IL-10) in serum and liver homogenate and alanine transaminase (ALT) in serum were determined by enzyme linked immunosorbent assay(ELISA). The injury of liver tissue was evaluated by histopathology. The expression of miR-155 in liver tissue was assessed by fluorescent quantitation reverse transcription-polymerase chain reaction (RT-PCR). The levels of TNF- α , IL-6 and IL-10 in serum and liver homogenate of septic mice increased with passage of time, and then the levels of TNF-α and IL-6 lowered after reaching the peak value, but remained higher than that of control group.TNF-α (ng/L) reached the peak value at 2 hours post-LPS-injection (serum: 1538.46 ± 102.12 vs. 64.52 ± 18.44,liver homogenate: 255.26 ± 41.23 vs. 60.21 + 13.55, both P<0.05). The level of IL-6 (μg/L) reached the peak value at 6 hours post-LPS-injection (serum: 875.33 ± 102.37 vs. 153.72 ± 20.67, liver homogenate: 9.22 + 0.82 vs. 3.35 ±0.36, both P<0.05), and that of IL-10 (ng/L) reached the peak value at 48 hours post-LPS-injection (serum: 520.13 ± 88.52 vs. 23.43 3.01, liver homogenate: 260.12 + 50.38 vs. 16.37 ± 3.71, both P<0.05). There were significant differences in above indexes between septic and control group (all P<0.05). The serum level of ALT (U/L) rose with passage of time, reaching the peak value at 48 hours post-LPS-injection (603.26 + 70.21 vs. 45.84 + 5.64, P<0.05). The values showed significant differences between septic and control group (P<0.05). A large number of leucocytic infiltration was found in liver. Hepatic tissue showed architectural distortion. Hepatocyte vacuolation and nodular necrosis were obvious at 12 hours post-LPS-injection. Relative expression of miR-155 was found to be increased at 2 hours post-LPS-injection, reaching its peak value at 12 hours post-LPS-injection [(72.96 ± 9.34)-fold of control group, P<0.05]. The increase in miR-155 expression might play an important role in the mechanism of liver injury during sepsis.

Effect of MicroRNA-155 on EGFRvIII Mediated Radiation Response in Glioblastoma Tumors

Effect of MicroRNA-155 on EGFRvIII Mediated Radiation Response in Glioblastoma Tumors

Effects of microRNA-155 on the growth of human lung cancer cell line 95D in vitro

背景与目的近年来的研究发现miRNAs（microRNAs）家族成员miR-155与肺癌的发生相关，然而具体机制不明。本研究拟探讨上调miR-155表达对人肺癌95D细胞体外生长的影响及其可能的作用机制，为后续深入研究miR-155在肺癌发生、发展中的作用提供新的实验依据。方法人肺癌95D细胞分为空白对照组、miR-155阴性对照组和miR-155转染组，分别作加入转染试剂、转染miR-155阴性对照和转染miR-155处理。Real-time PCR特异性探针法检测转染后95D细胞中miR-155的表达水平；应用MTT法检测miR-155对95D细胞增殖的抑制作用；流式细胞术检测95D细胞周期的分布；Western blot检测95D细胞SOS1蛋白的表达变化。结果Real-time PCR结果显示，与对照组相比，转染组95D细胞miR-155的表达水平明显增加（P < 0.05）；镜下可见转染miR-155的95D细胞生长减缓，形态发生改变；MT结果表明miR-155转染后，95D细胞增殖受到抑制，转染组和对照组存在明显差异（P < 0.05）；流式细胞术分析显示，与对照组相比，转染miR-155的95D细胞周期发生改变，G0/G1期细胞明显增多，而S期则明显减少（P < 0.05）；Western blot结果显示转染组95D细胞SOS1蛋白的表达明显降低（P < 0.05）。结论miR-155能明显抑制人肺癌95D细胞的体外生长，这可能与miR-155下调SOS1表达及诱导95D细胞G0/G1期阻滞相关。

MicroRNA-155 regulates angiotensin II type 1 receptor expression in umbilical vein endothelial cells from severely pre-eclamptic pregnant women

Angiotensin II is critical in pre-eclampsia pathogenesis. In addition, microRNA-155 regulates angiotensin II type1 receptor expression. We have explored the function of microRNA-155 in pre-eclamptic pregnant women. Human umbilical vein endothelial cells were isolated and cultured from healthy puerperant women and pre-eclampsia patients. The cells were transfected with a mature microRNA-155 plasmid. The effect of microRNA-155 was assessed by Northern blotting, in situ hybridization, quantitative real-time PCR, immunofluorescent staining and Western blotting. In addition, activation of extracellular signal-regulated kinase 1/2 was assessed by co-immunoprecipitation and Western blotting. Severely pre-eclamptic pregnant women expressed less mature miR-155 compared to healthy pregnant women. In addition, angiotensin II type 1 receptor expression decreased substantially in healthy cells and miR-155-transfected cells compared to miR-155-mutant-transfected cells and cells from pre-eclamptic patients. Mature miR-155 reduced angiotensin II-induced extracellular signal-regulated kinase 1/2 activation. In conclusion, endogenous mature miR-155 expression may be an important contributor to the pathogenesis of severe pre-eclampsia.