17-700 Sigma-AldrichMagna RIP™ RNA-Binding Protein Immunoprecipitation Kit

lncRNAs can exert many biological effects in several cancer types. MALAT1 is a kind of lncRNA which is greatly overexpressed in several tumors including non-small cell lung cancer (NSCLC). However, the mechanism of MALAT1 in NSCLC still remains unclear. In our current study, we concentrated on the biological mechanism of MALAT1 in NSCLC. It was observed that MALAT1 was significantly upregulated in five human NSCLC cells including A549, H23, H522, H1299, and H460 cells compared to normal bronchial epithelial cell line 16HBE cells. On the contrary, miR-124 was remarkably downregulated, which indicated a potential negative correlation between miR-124 and MALAT1. MALAT1 inhibition can increase miR-124 expression in A549 and H460 cells. In addition, miR-124 mimics were able to repress MALAT1 expression and miR124 inhibitors can promote MALAT1 levels. Then it was found that shMALAT1 can inhibit NSCLC cell proliferation, colony formation and apoptosis, which can be reversed by miR-124 inhibitors. Bioinformatic analysis predicted the correlation between miR-124 and MALAT1. In addition, STAT3 was found to be a novel mRNA target of miR-124. Downregulation of MALAT1 can inhibit NSCLC development by enhancing miR-124 and decreasing STAT3 expression. We speculated that MALAT1can act as a competing endogenous lncRNA (ceRNA) to modulate miR-124/STAT3 in NSCLC. Taken these together, we revealed that MALAT1/miR-124/STAT3 was involved in NSCLC development.

Recently, long noncoding RNAs (lncRNAs) have emerged as new gene regulators and prognostic biomarkers in several cancers, including gastric cancer (GC). In this study, we investigate the role of lncRNA ZEB1 antisense1 (ZEB1-AS1) on GC progression. In the present study, we found that ZEB1-AS1 expression was upregulated in GC tissues and cell lines. High ZEB1-AS1 expression was significantly correlated with advanced TNM stage, lymph node metastasis, and poor overall survival in GC patients. ZEB1-AS1 suppression reduced GC cell proliferation and invasion in vitro. Tumor formation assay in nude mice showed that ZEB1-AS1 inhibition suppressed GC cell growth. Quantitative real-time PCR showed that miR-335-5p expression was downregulated and negatively correlated with ZEB1-AS1 expression in GC tissues. And miR-335-5p expression was directly regulated by ZEB1-AS1. Furthermore, we found that inhibition of miR-335-5p abrogated the suppression of proliferation and invasion of GC cells induced by ZEB1-AS1 depletion. Collectively, ZEB1-AS1 is critical for the proliferation and invasion of GC cells by regulating miR-335-5p. Our findings indicated that ZEB1-AS1 might offer potential novel therapeutic targets for GC patients.

Slo2 channels are large-conductance potassium channels abundantly expressed in the nervous system. However, it is unclear how their expression level in neurons is regulated. Here we report that HRPU-2, an RNA-binding protein homologous to mammalian heterogeneous nuclear ribonucleoprotein U (hnRNP U), plays an important role in regulating the expression of SLO-2 (a homolog of mammalian Slo2) in Caenorhabditis elegans Loss-of-function (lf) mutants of hrpu-2 were isolated in a genetic screen for suppressors of a sluggish phenotype caused by a hyperactive SLO-2. In hrpu-2(lf) mutants, SLO-2-mediated delayed outward currents in neurons are greatly decreased, and neuromuscular synaptic transmission is enhanced. These mutant phenotypes can be rescued by expressing wild-type HRPU-2 in neurons. HRPU-2 binds to slo-2 mRNA, and hrpu-2(lf) mutants show decreased SLO-2 protein expression. In contrast, hrpu-2(lf) does not alter the expression of either the BK channel SLO-1 or the Shaker type potassium channel SHK-1. hrpu-2(lf) mutants are indistinguishable from wild type in gross motor neuron morphology and locomotion behavior. Together, these observations suggest that HRPU-2 plays important roles in SLO-2 function by regulating SLO-2 protein expression, and that SLO-2 is likely among a restricted set of proteins regulated by HRPU-2. Mutations of human Slo2 channel and hnRNP U are strongly linked to epileptic disorders and intellectual disability. The findings of this study suggest a potential link between these two molecules in human patients.SIGNIFICANCE STATEMENT Heterogeneous nuclear ribonucleoprotein U (hnRNP U) belongs to a family of RNA-binding proteins that play important roles in controlling gene expression. Recent studies have established a strong link between mutations of hnRNP U and human epilepsies and intellectual disability. However, it is unclear how mutations of hnRNP U may cause such disorders. This study shows that mutations of HRPU-2, a worm homolog of mammalian hnRNP U, result in dysfunction of a Slo2 potassium channel, which is critical to neuronal function. Because mutations of Slo2 channels are also strongly associated with epileptic encephalopathies and intellectual disability in humans, the findings of this study point to a potential mechanism underlying neurological disorders caused by hnRNP U mutations.

Accumulating evidence has supported the significance of lncRNAs in tumorigenesis. Recently, some studies indicate the oncogenic role of lncRNA Nuclear Enriched Abundant Transcript 1 (NEAT1) in hepatocellular carcinoma (HCC). In our present study, we focused on the biological mechanisms through which NEAT1 can regulate HCC development. We found that NEAT1 was greatly upregulated in human HCC cell lines including Huh7, Hep3B, HepG2, Bel-7404, and SK-Hep1 cells compared to the normal human liver cell line LO2. In addition, we observed that miR-485 was significantly downregulated in HCC cells. It was implied that miR-485 was increased by sh-NEAT1 and miR-485 can modulate NEAT1 expression negatively. Meanwhile, NEAT1inhibiton can repress HCC growth, migration, and invasion capacity in HepG2 and Hep3B cells. Through performing bioinformatic analysis, dual-luciferase reporter test, RNA-binding protein immunoprecipitation, and RNA pull-down assay, miR-485 was confirmed as a interacting target of NEAT1. Additionally, STAT3 was recognized as a direct target of miR-485 and miR-485 mimics can inhibit STAT3 expression. It was demonstrated that NEAT1 can increase STAT3 levels while miR-485 mimics can repress STAT3. Moreover, we found that sh-STAT3 was able to restrain HCC cell migration and invasion process. NEAT1 can act as a competing endogenous lncRNA (ceRNA) to regulated STAT3 by sponging miR-485 in HCC. Taken these together, NEAT1 can be used as an important biomarker in HCC diagnosis and treatment.

The cyclic expression of pituitary gonadotropin-releasing hormone receptors (GnRHRs) may be an important checkpoint for leptin regulatory signals. Gonadotrope Lepr-null mice have reduced GnRHR levels, suggesting these receptors may be leptin targets. To determine if leptin stimulated GnRHR directly, primary pituitary cultures or pieces were exposed to 1 to 100 nM leptin. Leptin increased GnRHR protein levels and the percentages of gonadotropes that bound biotinylated analogs of gonadotropin-releasing hormone (bio-GnRH) but had no effect on Gnrhr messenger RNA (mRNA). An in silico analysis revealed three consensus Musashi (MSI) binding elements (MBEs) for this translational control protein in the 3' untranslated region (UTR) of Gnrhr mRNA. Several experiments determined that these Gnrhr mRNA MBE were active: (1) RNA electrophoretic mobility shift assay analyses showed that MSI1 specifically bound Gnrhr mRNA 3'-UTR; (2) RNA immunoprecipitation of pituitary fractions with MSI1 antibody pulled down a complex enriched in endogenous MSI protein and endogenous Gnrhr mRNA; and (3) fluorescence reporter assays showed that MSI1 repressed translation of the reporter coupled to the Gnrhr 3'-UTR. In vitro, leptin stimulation of pituitary pieces reduced Msi1 mRNA in female pituitaries, and leptin stimulation of pituitary cultures reduced MSI1 proteins selectively in gonadotropes identified by binding to bio-GnRH. These findings show that leptin's direct stimulatory actions on gonadotrope GnRHR correlate with a direct inhibition of expression of the posttranscriptional regulator MSI1. We also show MSI1 interaction with the 3'-UTR of Gnrhr mRNA. These findings now open the door to future studies of leptin-modulated posttranscriptional pathways.

More and more evidences have ensured the crucial functions of long non-coding RNAs (lncRNAs) in multiple tumors. It has been discovered that lncRNA-SNHG16 is involved in many tumors. Even so, it is still necessary to study SNHG16 comprehensively in bladder cancer. In terms of our study, the level of SNHG16 both in the tumor tissues and cell lines was measured and the relationship among SNHG16, clinicopathological traits and prognosis was explored. Interference assays were applied to determine the biological functions of SNHG16. It was discovered that the level of SNHG16 was evidently enhanced both in tissues and cell lines of bladder cancer. Patients with highly expressed SNHG16 suffered from poor overall survival. Multivariable Cox proportional hazards regression analysis implied that highly expressed SNHG16 could be used as an independent prognostic marker. It could be known from functional assays that silenced SNHG16 impaired cell proliferation, owing to the effects of SNHG16 on cell cycle and apoptosis. Finally, mechanism experiments revealed that SNHG16 could epigenetically silence the expression of p21. The facts above pointed out that lncRNA-SNHG16 might be quite vital for the diagnosis and development of bladder cancer, and could even become an important therapeutic target for bladder cancer.

LncRNAs are increasingly verified to be aberrantly expressed in cancers. The abnormal expression of lncRNAs has turned out to be closely related to tumorigenesis or tumor progression. It has been reported that lncRNA OPI5-AS1 serves as a crucial regulator in tumors. However, the specific function of OIP5-AS1 on the progression of lung adenocarcinoma is still uncertain. In this paper, we mainly elucidated that OIP5-AS1 exerts oncogenic functions in human lung adenocarcinoma through targeting miR-448. We inspected that the expression of OIP5-AS1 was definitely high in lung adenocarcinoma tissues and cells, while miR-448 was sluggishly expressed in lung adenocarcinoma. OIP5-AS1 and miR-448 was negatively related to each other, the result was obtained from Pearson correlation analysis. We discovered a fact that OIP5-AS1 could directly sponge miR-448 through using dual luciferase reporter assay, RIP assay and RNA pull-down assay. Cell proliferation, migration and invasion were restrained after we disrupted the expression of OIP5-AS1 in lung adenocarcinoma. We also certified that OIP5-AS1 could sponge and regulate miR-448 to affect cell function in lung adenocarcinoma. MiR-448 could target Bcl-2 and affect the expression of Bcl-2. Then, we discovered that the expression of OIP5-AS1 and Bcl-2 was positively related. So we affirmed that lncRNA OIP5-AS1 modulated the expression of Bcl-2 by targeting miR-448 in lung adenocarcinoma cells.

This study aimed to investigate the mechanism of lncRNA-KCNQ1OT1 on macrophage polarization to ameliorate particle-induced osteolysis. We used polymethylmethacrylate (PMMA) to induce primary bone marrow-derived macrophages (BMMs) obtained from mice and the RAW264.7 cell line, and found that the tumor necrosis factor-alpha (TNF-α) concentration and inducible nitric oxide synthase (iNOS) expression was increased, while interleukin (IL)-10 concentration and Arg1 expression were decreased in PMMA-induced cells. KCNQ1OT1 and IL-10 expression were both suppressed and miR-21a-5p expression was promoted in PMMA-induced cells. Overexpression of KCNQ1OT1 reversed the effect of PMMA on RAW264.7 cells, such as the reduced TNF-α concentration and iNOS expression, and increased IL-10 concentration and Arg1 expression in PMMA-induced cell transfected with pcDNA-KCNQ1OT1. The luciferase assay confirmed that IL-10 is a target of miR-21a-5p. RNA immunoprecipitation (RIP) and RNA pull-down experiments demonstrated that KCNQ1OT1 functions as a miR-21a-5p decoy. Thus, lncRNA KCNQ1OT1 induces M2 macrophage polarization to ameliorate particle-induced osteolysis by inhibiting miR-21a-5p.

Oxidized low-density lipoprotein (oxLDL) indu-ces macrophage inflammation and lipid uptake, and serves important roles in the development of atherosclerosis. The long non-coding RNA (lncRNA) nuclear paraspeckle assembly transcript 1 (neat1) has two isoforms; the longer isoform, neat1_2, mediates the formation of subnuclear structures called paraspeckles. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR), western blotting and RNA protein immunoprecipitation (RIP), revealed that oxLDL induced paraspeckle formation in the THP‑1 cell line. Additionally, the nuclear factor‑κB and p38 pathways were observed to be involved in neat1 transcription. To investigate the role of paraspeckles in oxLDL‑induced macrophage inflammation and lipid uptake, macrophages were transfected with small interfering RNAs against NEAT1, NEAT1_2, non‑POU domain-containing octamer-binding (NONO) and splicing factor proline and glutamine rich prior to oxLDL incubation. In addition, inflammation‑associated pathways and scavenger receptors were analyzed by performing western blotting and RT‑qPCR. p65 phosphorylation and cluster of differentiation 36 (CD36) were demonstrated to serve roles in paraspeckle‑mediated inflammation and lipid uptake, respectively. To determine the underlying mechanism, RIP was preformed, which revealed that NONO binds CD36 mRNA to decrease its expression. In conclusion, oxLDL induced neat1_2‑mediated paraspeckle formation. Paraspeckles participate in oxLDL‑induced macrophage inflammation and lipid uptake by regulating p65 phosphorylation and CD36 mRNA.

HnRNP D, better known as AUF1, is an extensively studied protein that controls a variety of cellular pathways. Consequently, its expression has to be tightly regulated to prevent the onset of pathologies. In contrast, the cellular functions and regulation of its ubiquitously expressed paralog hnRNP DL are barely explored. Here, we present an intricate crosstalk between these two proteins. Both hnRNP D and DL are able to control their own expression by alternative splicing of cassette exons in their 3'UTRs. Exon inclusion produces mRNAs degraded by nonsense-mediated decay. Moreover, hnRNP D and DL control the expression of one another by the same mechanism. Thus, we identified two novel ways of how hnRNP D expression is controlled. The tight interconnection of expression control directly links hnRNP DL to hnRNP D-related diseases and emphasizes the importance of a systematic analysis of its cellular functions.