Overexpression of NF90-NF45 Represses Myogenic MicroRNA Biogenesis, Resulting in Development of Skeletal Muscle Atrophy and Centronuclear Muscle Fibers

Interleukin-2 enhancer binding factor 2 negatively regulates the replication of duck hepatitis A virus type 1 by disrupting the RNA-dependent RNA polymerase activity of 3D polymerase

The interaction between viral components and cellular proteins plays a crucial role in viral replication. In a previous study, we showed that the 3'-untranslated region (3'-UTR) is an essential element for the replication of duck hepatitis A virus type 1 (DHAV-1). However, the underlying mechanism is still unclear. To gain a deeper understanding of this mechanism, we used an RNA pull-down and a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry assay to identify new host factors that interact with the 3'-UTR. We selected interleukin-2 enhancer binding factor 2 (ILF2) for further analysis. We showed that ILF2 interacts specifically with both the 3'-UTR and the 3D polymerase (3Dpol) of DHAV-1 through in vitro RNA pull-down and co-immunoprecipitation assays, respectively. We showed that ILF2 negatively regulates viral replication in duck embryo fibroblasts (DEFs), and that its overexpression in DEFs markedly suppresses DHAV-1 replication. Conversely, ILF2 silencing resulted in a significant increase in viral replication. In addition, the RNA-dependent RNA polymerase (RdRP) activity of 3Dpol facilitated viral replication by enhancing viral RNA translation efficiency, whereas ILF2 disrupted the role of RdRP in viral RNA translation efficiency to suppress DHAV-1 replication. At last, DHAV-1 replication markedly suppressed the expression of ILF2 in DEFs, duck embryo hepatocytes, and different tissues of 1 day-old ducklings. A negative correlation was observed between ILF2 expression and the viral load in primary cells and different organs of young ducklings, suggesting that ILF2 may affect the viral load both in vitro and in vivo.

The relationship between prognosis of patients with traumatic brain injury and microRNA biogenesis proteins

BACKGROUND

This study aims to investigate whether the expression levels of proteins involved in microRNA (miRNA) biogenesis vary in early- and late-stage traumatic brain injury (TBI) patients and to evaluate its effect on prognosis.

METHODS

Dicer, Drosha, DiGeorge Syndrome Critical Region eight (DGCR8), Exportin5 (XPO5), and Argonaute2 (AGO2) levels were measured in the blood samples of severe TBI patients collected 4-6 h and 72 h after the trauma and compared with the control group. Prognostic follow-up of the patients was performed using the Glasgow Coma Scale score.

RESULTS

There were no statistically significant changes in the expression of the miRNA biogenesis proteins Dicer, Drosha, DGCR8, XPO5, and AGO2 in patients with severe TBI. However, the expression of Dicer increased in the patients who improved from the severe TBI grade to the mild TBI grade, and the expression of AGO2 decreased in most of these patients. The Dicer expression profile was found to increase in patients discharged from the intensive care unit in a short time.

CONCLUSION

MicroRNAs and their biogenesis proteins may guide prognostic and therapeutic decisions for patients with TBI in the future.

The Polyvalent Role of NF90 in RNA Biology

Double-stranded RNA-binding proteins (dsRBPs) are major players in the regulation of gene expression patterns. Among them, Nuclear Factor 90 (NF90) has a plethora of well-known functions in viral infection, transcription, and translation as well as RNA stability and degradation. In addition, NF90 has been identified as a regulator of microRNA (miRNA) maturation by competing with Microprocessor for the binding of pri-miRNAs in the nucleus. NF90 was recently shown to control the biogenesis of a subset of human miRNAs, which ultimately influences, not only the abundance, but also the expression of the host gene and the fate of the mRNA target repertoire. Moreover, recent evidence suggests that NF90 is also involved in RNA-Induced Silencing Complex (RISC)-mediated silencing by binding to target mRNAs and controlling their translation and degradation. Here, we review the many, and growing, functions of NF90 in RNA biology, with a focus on the miRNA pathway and RISC-mediated gene silencing.

Regulated dicing of pre-mir-144 via reshaping of its terminal loop

Although the route to generate microRNAs (miRNAs) is often depicted as a linear series of sequential and constitutive cleavages, we now appreciate multiple alternative pathways as well as diverse strategies to modulate their processing and function. Here, we identify an unusually profound regulatory role of conserved loop sequences in vertebrate pre-mir-144, which are essential for its cleavage by the Dicer RNase III enzyme in human and zebrafish models. Our data indicate that pre-mir-144 dicing is positively regulated via its terminal loop, and involves the ILF3 complex (NF90 and its partner NF45/ILF2). We provide further evidence that this regulatory switch involves reshaping of the pre-mir-144 apical loop into a structure that is appropriate for Dicer cleavage. In light of our recent findings that mir-144 promotes the nuclear biogenesis of its neighbor mir-451, these data extend the complex hierarchy of nuclear and cytoplasmic regulatory events that can control the maturation of clustered miRNAs.

NF90-NF45 is essential for β cell compensation under obesity-inducing metabolic stress through suppression of p53 signaling pathway

The Nuclear Factor 90 (NF90)-NF45 complex has been known to regulate the progression of transcription, mRNA stability, translational inhibition, RNA export and microRNA biogenesis. However, the physiological functions of the NF90-NF45 complex remain unclear. We newly discovered that the NF90-NF45 complex was expressed in primary β cells and established cell lines. Therefore, in this study, we focused on the function of the endogenous NF90-NF45 complex in the β cells. To investigate this issue, we generated β-cell-specific NF90-NF45 deficient mice. These mice exhibited hyperglycaemia and lower plasma insulin levels under a high fat diet together with decreased islet mass. To uncover this mechanism, we performed a whole-genome expression microarray of the total RNA prepared from β cell lines treated with siRNAs targeting both NF90 and NF45. In this result, we found an activation of p53 signaling in the NF90-NF45-knockdown cells. This activation was supported by elevation of luciferase activity derived from a reporter plasmid harboring p53 binding sites in the NF90-NF45-knockdown cells. Furthermore, the knockdown of NF90-NF45 resulted in a significant retardation of the β cell line growth rates. Importantly, a dominant negative form of p53 rescues the growth retardation in BTC6 cells depleted of NF90-NF45, suggesting that NF90-NF45 would be positively involved in β cell proliferation through suppression of p53 signal pathway. Taken together, NF90-NF45 is essential for β cell compensation under obesity-inducing metabolic stress via repression of p53 signaling.

ILF3 represses repeat-derived microRNAs targeting RIG-I mediated type I interferon response

MicroRNAs (miRNAs) play important roles in regulated gene expression and miRNA biogenesis is also subject to regulation, together constituting critical regulatory circuitries in numerous physiological and pathological processes. As a dsRNA binding protein, interleukin enhancer binding factor 3 (ILF3) has been implicated as a negative regulator in miRNA biogenesis, but the mechanism and specificity have remained undefined. Here, combining small-RNA-seq and CLIP-seq, we showed that ILF3 directly represses many miRNAs or perhaps other types of small RNAs annotated in both miRBase and MirGeneDB. We demonstrated that ILF3 preferentially binds to A/U-enriched motifs, which tend to lengthen and/or stabilize the stem-loop in pri-miRNAs, thereby effectively competing with the Microprocessor to block miRNA biogenesis. Focusing on the biological function of ILF3-suppressed miR-582-3p, we discovered that this LINE-derived miRNA targets a critical interferon-inducible gene RIG-I for repression, thus establishing a novel ILF3/miR-582/RIG-I axis in the antiviral response.

Donepezil, an anti-Alzheimer's disease drug, promotes differentiation and regeneration in injured skeletal muscle through the elevation of the expression of myogenic regulatory factors

We previously demonstrated that donepezil, an anti-Alzheimer's disease drug, improved skeletal muscle atrophy by enhancing the angiogenesis of endothelial cells and activating the proliferation of satellite cells in a mouse model of peripheral arterial disease. However, the effect of donepezil on muscle differentiation during regeneration remains unclear. Therefore, we measured the expressions of myogenic regulatory factors and late muscle differentiation markers in donepezil-treated C2C12 myoblast cells before and after the induction of cell differentiation. The results indicate that the expressions of myogenin, troponin T (TnT) and myosin heavy chain (MyHC) were significantly increased and myotube formation was accelerated in donepezil-treated cells under the differentiation condition. However, the promotive effect of donepezil on muscle differentiation could not be reproduced by the addition of acetylcholine (ACh) and was not disrupted after treatment with ACh receptor blockers. Moreover, other kinds of acetylcholinesterase inhibitors failed to promote muscle differentiation in C2C12 cells. These results indicate that the specific characteristics of donepezil in the promotion of muscle differentiation are independent of its acetylcholinesterase-inhibitory action. We further found that donepezil induced an incremental shift of the cross-sectional area of myofibers and elevated the expressions of myogenin, TnT and MyHC in a mouse model of cardiotoxin injury. These results suggest that donepezil promotes the differentiation of muscle regeneration upon injury via the elevation of the expressions of myogenic regulatory factors and late muscle differentiation markers. Our findings suggest that donepezil can be a useful therapeutic agent for injured skeletal muscle treatment.

Metabolomic Characterization Reveals ILF2 and ILF3 Affected Metabolic Adaptions in Esophageal Squamous Cell Carcinoma

Esophageal cancer (EC) is a common malignant disease in eastern countries. However, a study of the metabolomic characteristics associated with other biological factors in esophageal squamous cell carcinoma (ESCC) is limited. Interleukin enhancer binding factor 2 (ILF2) and ILF3, double-stranded RNA-binding proteins, have been reported to contribute to the occurrence and development of various types of malignancy. Nevertheless, the underlying functions of ILF2 and ILF3 in ESCC metabolic reprogramming have never been reported. This study aimed to contribute to the metabolic characterization of ESCC and to investigate the metabolomic alterations associated with ILF2 and ILF3 in ESCC tissues. Here, we identified 112 differential metabolites, which were mainly enriched in phosphatidylcholine biosynthesis, fatty acid metabolism, and amino acid metabolism pathways, based on liquid chromatography–mass spectrometry and capillary electrophoresis–mass spectrometry approaches using ESCC tissues and paired para-cancer tissues from twenty-eight ESCC patients. In addition, ILF2 and ILF3 expression were significantly elevated in EC tissues compared to the histologically normal samples, and closely associated with PI3K/AKT and MAPK signaling pathways in ESCC. Moreover, in ESCC tissues with a high ILF2 expression, several short-chain acyl-carnitines (C3:0, C4:0, and C5:0) related to the BCAA metabolic pathway and long-chain acyl-carnitines (C14:0, C16:0, C16:0-OH, and C18:0) involved in the oxidation of fatty acids were obviously upregulated. Additionally, a series of intermediate metabolites involved in the glycolysis pathway, including G6P/F6P, F1,6BP, DHAP, G3P, and 2,3BPG, were remarkably downregulated in highly ILF3-expressed ESCC tissues compared with the corresponding para-cancer tissues. Overall, these findings may provide evidence for the roles of ILF2 and ILF3 during the process of ESCC metabolic alterations, and new insights into the development of early diagnosis and treatment for ESCC. Further investigation is needed to clarify the underlying mechanism of ILF2 and ILF3 on acyl-carnitines and the glycolysis pathway, respectively.

Functional roles of non-coding RNAs in atrophy

Atrophy is defined as a reduction in cell, organ, or tissue size after reaching their normal mature sizes because of loss of organelles, cytoplasmic compartments, and proteins. This process is also involved in the pathogenesis of human disorders. Inadequate nourishment, poor circulation, inadequate hormonal support, defects in nerve supply of the tissue, disproportionate induction of apoptosis in the tissue, and absence of exercise are some underlying causes of atrophy. Recently, several non-coding RNAs (ncRNAs) have been identified that regulate atrophy, thus participating in the pathobiology of related disorders such as neurodegenerative/ neuromuscular diseases, age-related muscle atrophy, and cardiac tissue atrophy. In the current review, we have focused on two classes of ncRNAs namely long ncRNAs (lncRNAs) and microRNAs (miRNAs) to unravel their participation in atrophy-associated disorders.

Deletion of interleukin enhancer binding factor 2 (ILF2) resulted in defective biliary development and bile flow blockage

PURPOSE

Biliary atresia (BA) is a devastating obstructive bile duct disease of newborns. BA has the highest incidence in Asians (1/5000), and its pathogenesis is unclear. We identified BA-private rare copy number variants (CNVs; 22 duplications and 6 deletions). ILF2 gene locates in the chromosome region (Chr1:153410347-153,634,058) which was deleted in a nonsyndromic BA patient. However, it is still not known whether ILF2 plays a role in hepatobiliary development and its deletion impacts on the bile duct development.

METHODS

To investigate if ILF2 is required for biliary development, we knock-out the zebrafish homologs of ILF2 by CRISPR/Cas9 approach, and discover that deletion of ILF2 causes a defective biliary development and a lack of bile flow from the liver to the gall bladder in zebrafish, which is a resemblance of phenotypes of BA.

RESULTS

Our data indicate that ILF2 gene is required for biliary development; deletion of ILF2 impairs bile duct development and could contribute to BA pathogenesis. This will be the first study to functionally evaluate the genes interfered by BA-private CNVs in hepatobiliary development and in BA pathogenesis.

CONCLUSIONS

Such functional study may reveal the potential value of these BA-private CNVs in the disease pathogenesis for BA.

LEVEL OF EVIDENCE

N/A (animal and laboratory study).

lncRNA AK085865 Promotes Macrophage M2 Polarization in CVB3-Induced VM by Regulating ILF2-ILF3 Complex-Mediated miRNA-192 Biogenesis

Accumulating evidence indicates that macrophage polarization plays a crucial role in coxsackievirus B3 (CVB3)-induced viral myocarditis (VM). Our previous study demonstrated that long noncoding ribonucleic acid (lncRNA) AK085865 ablation confers susceptibility to VM by regulating macrophage polarization. However, the detailed molecular mechanisms by which AK085865 regulates macrophage polarization remain to be explored. In this study, we found that AK085865 specifically interacts with interleukin enhancer-binding factor 2 (ILF2) and facilitates M2 macrophage polarization by functioning as a negative regulator in the ILF2-ILF3 complex-mediated microRNA (miRNA or miR) processing pathway. miR-192 was downregulated, whereas the levels of pri-miR-192 were significantly increased in bone marrow-derived macrophages (BMDMs) from AK085865^-/- mice compared with the BMDMs from wild-type (WT) mice. Conversely, knockdown of ILF2 resulted in elevated levels of mature miR-192 and decreased expression of pri-miR-192 in BMDMs from AK085865^-/- mice. Moreover, miR-192 overexpression promoted macrophage M2 polarization in vitro, and interleukin-1 receptor-associated kinase 1 (IRAK1) was identified as a direct target. miR-192 overexpression effectively rescued mice from lethal myocarditis caused by CVB3 infection and switched myocardial-infiltrating macrophages to a predominant M2 phenotype. Collectively, our findings uncover a critical mechanism of AK085865 in the regulation of macrophage polarization in vitro and in vivo and provide a potential, clinically significant therapeutic target.

Function of Dicer with regard to Energy Homeostasis Regulation, Structural Modification, and Cellular Distribution

As a type III ribonuclease (RNase III) specifically cleaving double-stranded RNA substrates into short fragments, Dicer is indispensable in a range of physi/pathologic processes, e.g., nutrient deprivation, hypoxia, or DNA damage. Therefore, much interest has been paid to the research of this protein as well as its products like microRNAs (miRNAs). The close relationship between Dicer levels and fluctuations of nutrient availability suggests that the protein participates in the regulation of systemic energy homeostasis. Through miRNAs, Dicer regulates the hypothalamic melanocortin-4 system and central autophagy promoting energy expenditure. Moreover, by influencing canonical energy sensors like adenosine monophosphate-activated protein kinase (AMPK) or mammalian target of rapamycin (mTOR), Dicer favors catabolism in the periphery. Taken together, Dicer might be targeted in the control of energy dysregulation. However, factors affecting its RNase activity should be noted. Firstly, modulation of structural integrity affects its role as a ribonuclease. Secondly, although previously known as a cytosolic endoribonuclease, evidence suggests Dicer can relocalize into the nucleus where it could also produce small RNAs. In this review, we probe into involvement of Dicer in energy homeostasis as well as its structural integrity or cellular distribution which affects its ability to produce miRNAs, in the hope of providing novel insights into its mechanism of action for future application.

Enterovirus 71 Represses Interleukin Enhancer-Binding Factor 2 Production and Nucleus Translocation to Antagonize ILF2 Antiviral Effects

Enterovirus 71 (EV71) infection causes hand-foot-mouth disease (HFMD), meningoencephalitis, neonatal sepsis, and even fatal encephalitis in children, thereby presenting a serious risk to public health. It is important to determine the mechanisms underlying the regulation of EV71 infection. In this study, we initially show that the interleukin enhancer-binding factor 2 (ILF2) reduces EV71 50% tissue culture infective dose (TCID50) and attenuates EV71 plaque-formation unit (PFU), thereby repressing EV71 infection. Microarray data analyses show that ILF2 mRNA is reduced upon EV71 infection. Cellular studies indicate that EV71 infection represses ILF2 mRNA expression and protein production in human leukemic monocytes (THP-1) -differentiated macrophages and human rhabdomyosarcoma (RD) cells. In addition, EV71 nonstructural protein 2B interacts with ILF2 in human embryonic kidney (HEK293T) cells. Interestingly, in the presence of EV71 2B, ILF2 is translocated from the nucleus to the cytoplasm, and it colocalizes with 2B in the cytoplasm. Therefore, we present a distinct mechanism by which EV71 antagonizes ILF2-mediated antiviral effects by inhibiting ILF2 expression and promoting ILF2 translocation from the nucleus to the cytoplasm through its 2B protein.

A negative feedback loop between nuclear factor 90 (NF90) and an anti-oncogenic microRNA, miR-7

Alterations in microRNAs (miRNAs) levels deeply correlate with tumorigenesis. However, the molecular mechanism for the regulation of the miRNA production in tumors is not fully understood. We previously reported that downregulation of miR-7, which is an anti-oncogenic miRNA, was caused by overexpression of the nuclear factor 90 (NF90)-nuclear factor 45 (NF45) complex through the binding of double-stranded (ds) RNA-binding proteins to primary miR-7, resulting in promotion of tumorigenesis (Higuchi et al 2016). During this study, we found that the level of NF90 protein was dramatically decreased by overexpression of miR-7. Interestingly, the miR-7-mediated reduction in NF90 family proteins was only observed in NF90 protein, but not in NF110 protein, which is a longer form of the NF90 gene. Luciferase reporter analysis indicated that the overexpression of miR-7 significantly repressed the luciferase activity in the coding region of NF90 mRNA harboring a predicted target sequence of miR-7. The luciferase activity of the reporter vector, which has a mutated miR-7 target site in the coding region, was the same in the control and miR-7 overexpressed cells. Furthermore, the translation of TARGET-tagged NF90 mRNA without the 3'UTR of the NF90 mRNA was inhibited by the overexpression of miR-7. These results imply that miR-7 suppresses NF90 at the protein level through the binding of miR-7 to the complementary site of the seed sequence in the coding region of the NF90 mRNA. We further confirmed increased endogenous NF90 protein levels in SK-N-SH cells transfected with antisense oligonucleotides targeting miR-7, indicating that miR-7-mediated translational repression of NF90 is a physiological event. Taken together with our previous findings (Higuchi et al 2016), it suggests that the level of NF90 is increased by a negative feedback loop between NF90 and miR-7 in tumor tissues under physiological conditions.

Interleukin enhancer binding factor 2 is a prognostic biomarker for breast cancer that also predicts neoadjuvant chemotherapy responses

Interleukin enhancer binding factor 2 (ILF2) participates in several aspects of DNA and RNA metabolism and regulates gene expression at multiple levels; however, its role in breast cancer remains undefined. The variant statuses of ILF2 in human breast cancer were evaluated using the COSMIC database. Altered ILF2 expression in normal breast tissue relative to cancer tissue and in breast cancer patients with different clinicopathological characteristics, molecular subtypes, clinical outcomes and chemotherapy responses were examined using the Oncomine, GOBO, Kaplan-Meier plotter and GEO datasets. To explore possible biological networks connected to ILF2 in breast cancer, we performed ingenuity pathway analysis on ILF2-related differentially expressed genes. We found that many breast cancers had increased ILF2 copy number variations and increased ILF2 expression. We also observed that elevated ILF2 expression was correlated with aggressive features, such as high histological grade, BRCA1 mutations, and the triple-negative/basal-like subtype, which resulted in shorter survival in these cases. Moreover, ILF2 expression predicted responses to anthracycline/taxane-based treatment. Ingenuity pathway analysis revealed that ILF2-related biological functions included promoting cell survival, viability, and proliferation, as well as cell cycle progression and DNA repair. Certain well-known oncogenes (MYC and HGF), cytokines (CSF2, IFNG and IL5) and microRNAs (miR-21, miR-155-5p and let-7) may participate in the ILF2 expression network in breast cancer. In summary, ILF2 is involved in the development and progression of breast cancer and may be a predictive biomarker for better responses to anthracycline/taxane-based treatments.

An NF90/NF110-mediated feedback amplification loop regulates dicer expression and controls ovarian carcinoma progression

Reduced expression of DICER, a key enzyme in the miRNA pathway, is frequently associated with aggressive, invasive disease, and poor survival in various malignancies. Regulation of DICER expression is, however, poorly understood. Here, we show that NF90/NF110 facilitates DICER expression by controlling the processing of a miRNA, miR-3173, which is embedded in DICER pre-mRNA. As miR-3173 in turn targets NF90, a feedback amplification loop controlling DICER expression is established. In a nude mouse model, NF90 overexpression reduced proliferation of ovarian cancer cells and significantly reduced tumor size and metastasis, whereas overexpression of miR-3173 dramatically increased metastasis in an NF90- and DICER-dependent manner. Clinically, low NF90 expression and high miR-3173-3p expression were found to be independent prognostic markers of poor survival in a cohort of ovarian carcinoma patients. These findings suggest that, by facilitating DICER expression, NF90 can act as a suppressor of ovarian carcinoma.

Noncoding RNAs in Muscle Atrophy

Denervation, disuse, fasting, and various diseases could induce skeletal muscle atrophy, which results in the decline of life quality and increase of the mortality risk for patients. Noncoding RNAs (ncRNAs) are implicated important in regulating gene expression. Thus, ncRNAs, especially microRNAs and long noncoding RNAs (lncRNAs), have gained widespread attention as crucial players in numerous physiological and pathological processes, including skeletal muscle atrophy. In this review, we comprehensively described the potential of circulating microRNAs as biomarkers, summarized the profiling of microRNAs and lncRNAs in atrophying muscles, as well as discussed the effects and underlying mechanisms of microRNA machinery proteins, microRNAs, and lncRNAs in skeletal muscle atrophy. Considering the large quantity and variety of ncRNAs, the understanding of ncRNAs in muscle atrophy is still very limited. Future studies are needed to elucidate the possibility of ncRNAs as diagnosis biomarkers and therapeutic targets in muscle atrophy.

Interleukin-2 enhancer binding factor 2 interacts with the nsp9 or nsp2 of porcine reproductive and respiratory syndrome virus and exerts negatively regulatory effect on the viral replication

Background

Porcine reproductive and respiratory syndrome virus (PRRSV) causes reproductive failures in sows and respiratory diseases in growing pigs, resulting in huge economic loss for the pig production worldwide. The nonstructural protein 9 (nsp9) and nonstructural protein 2 (nsp2) of PRRSV are known to play important roles in viral replication. Cellular interleukin-2 enhancer binding factor 2 (ILF2) participates in many cellular pathways and involves in life cycle of some viruses. In the present study, we analyzed the interaction of cellular ILF2 with the nsp9 and nsp2 of PRRSV in vitro and explored the effect of ILF2 on viral replication.

Methods

The interaction of ILF2 with the nsp9 or nsp2 of PRRSV was analyzed in 293FT cells and MARC-145 cells by co-immunoprecipitation (Co-IP) and the co-localization of ILF2 with the nsp9 or nsp2 of PRRSV in MARC-145 cell and pulmonary alveolar macrophages (PAMs) was examined by confocal immunofluorescence assay. The effect of ILF2 knockdown and over-expression on PRRSV replication was explored in MARC-145 cells by small interfering RNA (siRNA) and lentivirus transduction, respectively.

Results

The interaction of ILF2 with nsp9 or nsp2 was first demonstrated in 293FT cells co-transfected with ILF2-expressing plasmid and nsp9-expressing plasmid or nsp2-expressing plasmid. The interaction of endogenous ILF2 with the nsp9 or nsp2 of PRRSV was further confirmed in MARC-145 cells transduced with GFP-nsp9-expressing lentiviruses or infected with PRRSV JXwn06. The RdRp domain of nsp9 was shown to be responsible for its interaction with ILF2, while three truncated nsp2 were shown to interact with ILF2. Moreover, we observed that ILF2 partly translocated from the nucleus to the cytoplasm and co-localized with nsp9 and nsp2 in PRRSV-infected MARC-145 cells and PAMs. Finally, our analysis indicated that knockdown of ILF2 favored the replication of PRRSV, while over-expression of ILF2 impaired the viral replication in MARC-145 cells.

Conclusion

Our findings are the first to confirm that the porcine ILF2 interacts with the nsp9 and nsp2 of PRRSV in vitro, and exerts negatively regulatory effect on the replication of PRRSV. Our present study provides more evidence for understanding the roles of the interactions between cellular proteins and viral proteins in the replication of PRRSV.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-017-0794-5) contains supplementary material, which is available to authorized users.

SMARCE1 is required for the invasive progression of in situ cancers

Advances in mammography have sparked an exponential increase in the detection of early-stage breast lesions, most commonly ductal carcinoma in situ (DCIS). More than 50% of DCIS lesions are benign and will remain indolent, never progressing to invasive cancers. However, the factors that promote DCIS invasion remain poorly understood. Here, we show that SMARCE1 is required for the invasive progression of DCIS and other early-stage tumors. We show that SMARCE1 drives invasion by regulating the expression of secreted proteases that degrade basement membrane, an ECM barrier surrounding all epithelial tissues. In functional studies, SMARCE1 promotes invasion of in situ cancers growing within primary human mammary tissues and is also required for metastasis in vivo. Mechanistically, SMARCE1 drives invasion by forming a SWI/SNF-independent complex with the transcription factor ILF3. In patients diagnosed with early-stage cancers, SMARCE1 expression is a strong predictor of eventual relapse and metastasis. Collectively, these findings establish SMARCE1 as a key driver of invasive progression in early-stage tumors.

Suppression of MicroRNA-7 (miR-7) Biogenesis by Nuclear Factor 90-Nuclear Factor 45 Complex (NF90-NF45) Controls Cell Proliferation in Hepatocellular Carcinoma

MicroRNA-7 (miR-7)has been characterized as an anti-oncogenic microRNA (miRNA) in several cancers, including hepatocellular carcinoma (HCC). However, the mechanism for the regulation of miR-7 production in tumors remains unclear. Here, we identified nuclear factor 90 (NF90) and NF45 complex (NF90-NF45) as negative regulators of miR-7 processing in HCC. Expression of NF90 and NF45 was significantly elevated in primary HCC tissues compared with adjacent non-tumor tissues. To examine which miRNAs are controlled by NF90-NF45, we performed an miRNA microarray and quantitative RT-PCR analyses of HCC cell lines. Depletion of NF90 resulted in elevated levels of mature miR-7, whereas the expression of primary miR-7-1 (pri-miR-7-1) was decreased in cells following knockdown of NF90. Conversely, the levels of mature miR-7 were reduced in cells overexpressing NF90 and NF45, although pri-miR-7-1 was accumulated in the same cells. Furthermore, NF90-NF45 was found to bind pri-miR-7-1 in vitro These results suggest that NF90-NF45 inhibits the pri-miR-7-1 processing step through the binding of NF90-NF45 to pri-miR-7-1. We also found that levels of the EGF receptor, an oncogenic factor that is a direct target of miR-7, and phosphorylation of AKT were significantly decreased in HCC cell lines depleted of NF90 or NF45. Of note, knockdown of NF90 or NF45 caused a reduction in the proliferation rate of HCC cells. Taken together, NF90-NF45 stimulates an elevation of EGF receptor levels via the suppression of miR-7 biogenesis, resulting in the promotion of cell proliferation in HCC.

The plasma miR-125a, miR-361 and miR-133a are promising novel biomarkers for Late-Onset Hypogonadism

Circulating miRNAs have been shown to serve as diagnostic/prognostic biomarkers in cancers and other diseases. However, the role of plasma miRNAs in Late-onset hypogonadism (LOH) diagnosis is still unknown. Using Illumina HiSeq2000 sequencing at discovery phase, and then two-step validated by reverse transcriptase polymerase chain reaction (RT-PCR) assays in verification phases. We verified that the expression levels of miR-125a-5p, miR-361-5p and miR-133a-3p were significantly altered in LOH group compared to the control group. The area under the receiver operating characteristic (ROC) curve (AUC) is 0.682, 0.698 and 0.765, respectively. The combination of three miRNAs showed a larger AUC (0.835) that was more efficient for the diagnosis of LOH. Among three miRNAs, miR-133a-3p had the best diagnostic value for LOH with 68.2% sensitivity and 77.3% specificity. Regression analyses show that miR-133a-3p level was negatively associated with the ageing males’ symptoms (AMS) scale. However, miR-361-5p level was positively associated with serum testosterone concentrations. In summary, plasma miRNAs are differentially expressed between LOH and healthy controls. We validated three miRNAs that could act as novel biomarkers for diagnosis of LOH. These miRNAs may be involved in the development of LOH. However, further large and functional studies are warranted to confirm our findings.