Induction of miR-3648 Upon ER Stress and Its Regulatory Role in Cell Proliferation

Induction mechanisms of autophagy and endoplasmic reticulum stress in intestinal ischemia-reperfusion injury, inflammatory bowel disease, and colorectal cancer

In recent years, the incidence of intestinal ischemia-reperfusion injury (II/RI), inflammatory bowel disease (IBD), and colorectal cancer (CRC) has been gradually increasing, posing significant threats to human health. Autophagy and endoplasmic reticulum stress (ERS) play important roles in II/RI. Damage caused by ischemia and cellular stress can activate ERS, which in turn initiates autophagy to clear damaged organelles and abnormal proteins, thereby alleviating ERS and maintaining the intestinal environment. In IBD, chronic inflammation damages intestinal tissues and activates autophagy and ERS. Autophagy is initiated by upregulating ATG genes and downregulating factors that inhibit autophagy, thereby clearing abnormal proteins, damaged organelles, and bacteria. Simultaneously, persistent inflammatory stimulation can also trigger ERS, leading to protein imbalance and abnormal folding in the ER lumen. The activation of ERS can maintain cellular homeostasis by initiating the autophagy process, thereby reducing inflammatory responses and cell apoptosis in the intestine. In CRC, excessive cell proliferation and protein synthesis lead to increased ERS. The activation of ERS, regulated by signaling pathways such as IRE1α and PERK, can initiate autophagy to clear abnormal proteins and damaged organelles, thereby reducing the negative effects of ERS. It can be seen that autophagy and ERS play a crucial regulatory role in the development of intestinal diseases. Therefore, the progress in targeted therapy for intestinal diseases based on autophagy and ERS provides novel strategies for managing intestinal diseases. In this paper, we review the advances in regulation of autophagy and ERS in intestinal diseases, emphasizing the potential molecular mechanisms for therapeutic applications.

Integrated analysis of microRNA expression in tears of Kazakh patients with climatic droplet keratopathy in Xinjiang, China

Climatic droplet keratopathy (CDK) is a corneal diseases, which is characterized by increased oil-like deposits on the anterior elastic lamina and anterior stromal layer. Severe CDK can even cause blindness, with no specific available treatment. Besides. CDK is poorly understood in terms of its pathogenic mechanisms. Thus, to determine potential biomarkers for CDK, we analyzed the microRNA expression profile in tear samples from CDK patients and investigated their putative roles in the pathogenesis of CDK. Herein, miRNA sequencing and following bioinformatics analysis was performed to explore the roles of their target genes in CDK. A total of 67 differentially expressed miRNAs were identified, of which 25 were upregulated and 42 were downregulated. qPCR verification showed that among the up- and down-regulated miRNAs, expression of five and six, respectively, was most significantly different.The target genes of the differentially expressed miRNAs are involved in the FoxO signaling pathway, tumor necrosis factor (TNF) signaling pathway, and steroid hormone biosynthesis. Protein-protein interaction network analyses identified 20 hub genes, including PTEN, GSK3B, and SMAD3. In conclusion, the panel of differentially expressed miRNAs identified may have potential utility as early diagnostic biomarkers for CDK. Moreover, the TNF signaling pathway is a new potential target in CDK for the development of treatments.

Dissection of a Down syndrome-associated trisomy to separate the gene dosage-dependent and -independent effects of an extra chromosome

As an aneuploidy, trisomy is associated with mammalian embryonic and postnatal abnormalities. Understanding the underlying mechanisms involved in mutant phenotypes is broadly important and may lead to new strategies to treat clinical manifestations in individuals with trisomies, such as trisomy 21 [Down syndrome (DS)]. Although increased gene dosage effects because of a trisomy may account for the mutant phenotypes, there is also the possibility that phenotypic consequences of a trisomy can arise because of the presence of a freely segregating extra chromosome with its own centromere, i.e. a 'free trisomy' independent of gene dosage effects. Presently, there are no reports of attempts to functionally separate these two types of effects in mammals. To fill this gap, here we describe a strategy that employed two new mouse models of DS, Ts65Dn;Df(17)2Yey/+ and Dp(16)1Yey/Df(16)8Yey. Both models carry triplications of the same 103 human chromosome 21 gene orthologs; however, only Ts65Dn;Df(17)2Yey/+ mice carry a free trisomy. Comparison of these models revealed the gene dosage-independent impacts of an extra chromosome at the phenotypic and molecular levels for the first time. They are reflected by impairments of Ts65Dn;Df(17)2Yey/+ males in T-maze tests when compared with Dp(16)1Yey/Df(16)8Yey males. Results from the transcriptomic analysis suggest the extra chromosome plays a major role in trisomy-associated expression alterations of disomic genes beyond gene dosage effects. This model system can now be used to deepen our mechanistic understanding of this common human aneuploidy and obtain new insights into the effects of free trisomies in other human diseases such as cancers.

Identification of long non-coding RNA and circular RNA associated networks in cellular stress responses

Mammalian cells employ various adaptive responses to cope with multiple stresses to maintain homeostasis. Functional roles of non-coding RNAs (ncRNAs) in response to cellular stresses have been proposed, and systematical investigations about the crosstalk among distinct types of RNAs are required. Here, we challenged HeLa cells with thapsigargin (TG) and glucose deprivation (GD) treatments to induce endoplasmic reticulum (ER) and metabolic stresses, respectively. Ribosomal RNA (rRNA)-depleted RNA sequencing (RNA-seq) was then performed. Characterization of the RNA-seq data revealed a series of differentially expressed long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) with parallel changes responsive to both stimuli. We further constructed the lncRNA/circRNA-mRNA co-expressing network, competing endogenous RNA (ceRNA) network in the lncRNA/circRNA-miRNA-mRNA axis, and lncRNA/circRNA-RNA binding protein (RBP) interactome map. These networks indicated the potential cis and/or trans regulatory roles of lncRNAs and circRNAs. Moreover, Gene Ontology analysis demonstrated that these identified ncRNAs were associated with several essential biological processes known to be related to cellular stress responses. In conclusion, we systematically established functional regulatory networks of lncRNA/circRNA-mRNA, lncRNA/circRNA-miRNA-mRNA and lncRNA/circRNA-RBP to perceive the potential interactions and biological processes during cellular stresses. These results provided insights in ncRNA regulatory networks of stress responses and the basis for further identification of pivotal factors involved in cellular stress responses.

The diverse roles of miRNAs in HIV pathogenesis: Current understanding and future perspectives

Despite noteworthy progress made in the management and treatment of HIV/AIDS-related disease, including the introduction of the now almost ubiquitous HAART, there remains much to understand with respect to HIV infection. Although some roles that miRNAs play in some diseases have become more obvious of late, the roles of miRNAs in the context of HIV pathogenesis have not, as yet, been elucidated, and require further investigations. miRNAs can either be beneficial or harmful to the host, depending upon the genes they target. Some miRNAs target the 3' UTR of viral mRNAs to accomplish restriction of viral infection. However, upon HIV-1 infection, there are several dysregulated host miRNAs which target their respective host factors to either facilitate or abrogate viral infection. In this review, we discuss the miRNAs which play roles in various aspects of viral pathogenesis. We describe in detail the various mechanisms thereby miRNAs either directly or indirectly regulate HIV-1 infection. Moreover, the predictive roles of miRNAs in various aspects of the HIV viral life cycle are also discussed. Contemporary antiretroviral therapeutic drugs have received much attention recently, due to their success in the treatment of HIV/AIDS; therefore, miRNA involvement in various aspects of antiretroviral therapeutics are also elaborated upon herein. The therapeutic potential of miRNAs are discussed, and we also propose herein that the therapeutic potential of one specific miRNA, miR-34a, warrants further exploration, as this miRNA is known to target three host proteins to promote HIV-1 pathogenesis. Finally, future perspectives and some controversy around the expression of miRNAs by HIV-1 are also discussed.

miR-3648 promotes lung adenocarcinoma-genesis by inhibiting SOCS2 (suppressor of cytokine signaling 2)

Lung adenocarcinoma (LUAD) is the most common histologic subtype of lung cancer and is associated with high morbidity and mortality. We aimed to study the effects of microRNA-3648 (miR-3648) on LUAD by inhibiting its downstream target suppressor of cytokine signaling 2 (SOCS2) mRNA. miR-3648 expression was measured by real-time quantitative PCR in LUAD and normal lung epithelial cell lines. The direct interaction between miR-3648 and SOCS2 mRNA was identified through luciferase reporter and RNA pull-down assays. Cell viability, migration, and invasion were examined using cell functional assays. MiR-3648 was found to be overexpressed in LUAD cells and tissues. Overexpression of miR-3648 significantly enhanced cell proliferation, migration, and invasion abilities in LUAD cells. Furthermore, SOCS2 was targeted by miR-3648, and co-transfection of a miR-3648 inhibitor or si-SOCS2 reversed the suppressive effects of SOCS2 in PC9 and A549 cells. miR-3648 enhanced the proliferation and promoted migration and invasion of LUAD by inhibiting SOCS2. In conclusion, our results indicate that miR-3648 plays a pivotal role in LUADe progression and might thus provide a novel therapeutic strategy for patients with LUAD.

Development of a novel miR-3648-related gene signature as a prognostic biomarker in esophageal adenocarcinoma

Background

Esophageal adenocarcinoma (EA) is a typical immunogenic malignant tumor with a dismal 5-year survival rate lower than 20%. Although miRNA-3648 (miR-3648) is expressed abnormally in EA, its impact on the tumor immune microenvironment remains unknown. In this study, we sought to identify immune-related genes (IRGs) that are targeted by miR-3648 and develop an EA multigene signature.

Methods

The gene expression data of 87 EA tumor samples and 67 normal tissue samples from The Cancer Genome Atlas (TCGA) database and the Genotype-Tissue Expression (GTEx) database were downloaded, respectively. Weighted gene co-expression network analysis (WGCNA), the CIBERSORT algorithm, and Cox regression analysis were applied to identify IRGs and to construct a prognostic signature and nomogram.

Results

MiR-3648 was expectedly highly expressed in EA tumor tissues (P=2.6e-8), and related to the infiltration of activated natural killer cells (NK cells) and activated CD4 T lymphocytes (CD4 cells). A total of 70 miR-3648-targeted genes related to immune cell infiltration were identified. Among them, 4 genes (C10orf55, DLL4, PANX2, and NKAIN1) were closely related to overall survival (OS), and were thus selected to construct a 4-gene risk score (RS). The RS had a superior capability to predict OS [area under the curve (AUC) =0.740 for 1 year; AUC =0.717 for 3 years; AUC =0.622 for 5 years]. A higher score was indicative of a poorer prognosis than a lower score [hazard ratio (HR) =2.71; 95% confidence interval (CI): 1.45-5.09; P=0.002]. Furthermore, the nomogram formed by combining the RS and the TNM classification of malignant tumors (TNM stage) improved the accuracy of survival prediction [Harrell's concordance index (C-index) =0.698].

Conclusions

MiR-3648 may play a critical role in EA pathogenesis. The novel 4-gene signature may serve as a prognostic tool to manage patients with EA.

Quantitative proteomic analysis after neuroprotective MyD88 inhibition in the retinal degeneration 10 mouse

Progressive photoreceptor death occurs in blinding diseases such as retinitis pigmentosa. Myeloid differentiation primary response protein 88 (MyD88) is a central adaptor protein for innate immune system Toll-like receptors (TLR) and induces cytokine secretion during retinal disease. We recently demonstrated that inhibiting MyD88 in mouse models of retinal degeneration led to increased photoreceptor survival, which was associated with altered cytokines and increased neuroprotective microglia. However, the identity of additional molecular changes associated with MyD88 inhibitor-induced neuroprotection is not known. In this study, we used isobaric tags for relative and absolute quantification (iTRAQ) labelling followed by LC-MS/MS for quantitative proteomic analysis on the rd10 mouse model of retinal degeneration to identify protein pathways changed by MyD88 inhibition. Quantitative proteomics using iTRAQ LC-MS/MS is a high-throughput method ideal for providing insight into molecular pathways during disease and experimental treatments. Forty-two proteins were differentially expressed in retinas from mice treated with MyD88 inhibitor compared with control. Notably, increased expression of multiple crystallins and chaperones that respond to cellular stress and have anti-apoptotic properties was identified in the MyD88-inhibited mice. These data suggest that inhibiting MyD88 enhances chaperone-mediated retinal protection pathways. Therefore, this study provides insight into molecular events contributing to photoreceptor protection from modulating inflammation.

A Comparative Transcriptome Analysis of Human and Porcine Choroid Plexus Cells in Response to Streptococcus suis Serotype 2 Infection Points to a Role of Hypoxia

Streptococcus suis (S. suis) is an important opportunistic pathogen, which can cause septicemia and meningitis in pigs and humans. Previous in vivo observations in S. suis-infected pigs revealed lesions at the choroid plexus (CP). In vitro experiments with primary porcine CP epithelial cells (PCPEC) and human CP epithelial papilloma (HIBCPP) cells demonstrated that S. suis can invade and traverse the CP epithelium, and that the CP contributes to the inflammatory response via cytokine expression. Here, next generation sequencing (RNA-seq) was used to compare global transcriptome profiles of PCPEC and HIBCPP cells challenged with S. suis serotype (ST) 2 infected in vitro, and of pigs infected in vivo. Identified differentially expressed genes (DEGs) were, amongst others, involved in inflammatory responses and hypoxia. The RNA-seq data were validated via quantitative PCR of selected DEGs. Employing Gene Set Enrichment Analysis (GSEA), 18, 28, and 21 enriched hallmark gene sets (GSs) were identified for infected HIBCPP cells, PCPEC, and in the CP of pigs suffering from S. suis ST2 meningitis, respectively, of which eight GSs overlapped between the three different sample sets. The majority of these GSs are involved in cellular signaling and pathways, immune response, and development, including inflammatory response and hypoxia. In contrast, suppressed GSs observed during in vitro and in vivo S. suis ST2 infections included those, which were involved in cellular proliferation and metabolic processes. This study suggests that similar cellular processes occur in infected human and porcine CP epithelial cells, especially in terms of inflammatory response.

The ORF8 protein of SARS-CoV-2 induced endoplasmic reticulum stress and mediated immune evasion by antagonizing production of interferon beta

The open reading frame 8 (orf8) is an accessory protein of SARS-CoV-2. It has 121 amino acids with two genotypes, orf8L and orf8S. In this study, we overexpressed the orf8L and orf8S of SARS-CoV-2 as well as the orf8b of SARS-CoV to investigate their roles in the regulation of endoplasmic reticulum (ER) stress and the inhibition of interferon beta (IFNß) production. We found that the two genotypes of SARS-CoV-2 orf8 are capable of inducing ER stress without significant difference by triggering the activating transcription factor 6 (ATF6) and inositol-requiring enzymes 1 (IRE1) branches of the ER stress pathway. However, the third branch of ER stress pathway, i.e. the protein kinase-like ER kinase (PERK), was unaffected by the overexpression of SARS-CoV-2 orf8L or orf8S. Moreover, both orf8L and orf8S of SARS-CoV-2 are capable of down regulating the production of IFNß and interferon-stimulated genes (ISG), ISG15 and ISG56 induced by polyinosinic-polycytidylic acid (poly (I:C)). Moreover, we also found decreased nuclear translocation of Interferon regulatory factor 3 (IRF3), after overexpressing orf8L and orf8S induced by poly (I:C). Our data demonstrated that SARS-CoV-2 orf8 protein could induce ER stress by activating the ATF6 and IRE1 pathways, but not the PERK pathway, and functions as an interferon antagonist to inhibit the production of IFNß. However, these functions appeared not to be affected by the genotypes of SARS-CoV-2 orf8L and orf8S.

Microarray-based Analysis of Genes, Transcription Factors, and Epigenetic Modifications in Lung Cancer Exposed to Nitric Oxide

BACKGROUND/AIM

Nitric oxide (NO) is recognized as an important biological mediator that exerts several human physiological functions. As its nature is an aqueous soluble gas that can diffuse through cells and tissues, NO can affect cell signaling, the phenotype of cancer and modify surrounding cells. The variety of effects of NO on cancer cell biology has convinced researchers to determine the defined mechanisms of these effects and how to control this mediator for a better understanding as well as for therapeutic gain.

MATERIALS AND METHODS

We used bioinformatics and pharmacological experiments to elucidate the potential regulation and underlying mechanisms of NO in non-small a lung cancer cell model.

RESULTS

Using microarrays, we identified a total of 151 NO-regulated genes (80 up-regulated genes, 71 down-regulated genes) with a strong statistically significant difference compared to untreated controls. Among these, the genes activated by a factor of more than five times were: DCBLD2, MGC24975, RAB40AL, PER3, RCN1, MRPL51, PTTG1, KLF5, NFIX. On the other hand, the expression of RBMS2, PDP2, RBAK, ORMDL2, GRPEL2, ZNF514, MTHFD2, POLR2D, RCBTB1, JOSD1, RPS27, GPR4 genes were significantly decreased by a factor of more than five times. Bioinformatics further revealed that NO exposure of lung cancer cells resulted in a change in transcription factors (TFs) and epigenetic modifications (histone modification and miRNA). Interestingly, NO treatment was shown to potentiate cancer stem cell-related genes and transcription factors Oct4, Klf4, and Myc.

CONCLUSION

Through this comprehensive approach, the present study illustrated the scheme of how NO affects molecular events in lung cancer cells.

New Conjugated Compound T5 Epidioxy-Sterol-ANB Inhibits the Growth of Mycobacterium tuberculosis Affecting the Cholesterol and Folate Pathways

The upsurge and persistence of drug resistant strains of Mycobacterium tuberculosis (Mtb) is an important limitant to the battery of drugs available for the elimination of tuberculosis (TB). To avoid future scarcity of antibiotics against Mtb, it is important to discover new effective anti-mycobacterial agents. In this study, we present data from a series of experiments to determine in vitro and in vivo anti-mycobacterial activity of a library of epidioxy-sterol analogs. We test 15 compounds for their ability to reduce the viability of Mtb. We found that one compound called T5 epidioxy-sterol-ANB display significant potency against Mtb in vitro specifically inside macrophages but without effectivity in axenic cultures. A viability assay confirms that this T5 compound is less toxic for macrophages in vitro as compared to the current Mtb drug Rifampicin at higher concentrations. We use a transcriptomic analysis of Mtb inside macrophages after T5 epidioxy-sterol-ANB treatment, and we found a significant down-regulation of enzymes involved in the cholesterol and folic acid pathways. In vivo, significant differences were found in the lungs and spleen CFUs of Mtb infected mice treated with the T5 epidioxy-sterol-ANB as compared with the untreated control group, which provides additional evidence of the effectivity of the T5 compound. Altogether these results confirm the potential of this T5 epidioxy-sterol-ANB compound against Mtb.

Asymmetrical methyltransferase PRMT3 regulates human mesenchymal stem cell osteogenesis via miR-3648

Histone arginine methylation, which is catalyzed by protein arginine methyltransferases (PRMTs), plays a key regulatory role in various biological processes. Several PRMTs are involved in skeletal development; however, their role in the osteogenic differentiation of mesenchymal stem cells (MSCs) is not completely clear. In this study, we aimed to elucidate the function of PRMT3, a type-I PRMT that catalyzes the formation of ω-mono- or asymmetric dimethyl arginine, in MSCs osteogenesis. We found that PRMT3 promoted MSCs osteogenic commitment and bone remodeling. PRMT3 activated the expression of miR-3648 by enhancing histone H4 arginine 3 asymmetric dimethylation (H4R3me2a) levels at promoter region of the gene. Overexpression of miR-3648 rescued impaired osteogenesis in PRMT3-deficient cells. Moreover, administration of Prmt3 shRNA or a chemical inhibitor of PRMT3 (SGC707) caused an osteopenia phenotype in mice. These results indicate that PRMT3 is a potential therapeutic target for the treatment of bone regeneration and osteopenia disorders.

MicroRNA-3648 Is Upregulated to Suppress TCF21, Resulting in Promotion of Invasion and Metastasis of Human Bladder Cancer

Although microRNAs (miRNAs) are well-known for their potential in cancer, the function and mechanisms of miR-3648 have barely been explored in any type of cancer. We show here that miR-3648 is upregulated in human BC tissues in comparison with adjacent non-tumor tissues. Functional studies showed that inhibition of miR-3648 expression in the human invasive BC UMUC3 and T24T cell lines decreased migration and invasion in vitro and suppressed lung metastasis in vivo, whereas miR-3648 overexpression promoted BC cell migration and invasion. A bioinformatics screen and mRNA 3' UTR luciferase reporter assay showed that transcription factor 21 (TCF21) was a direct target of miR-3648, and the results obtained from using a miR-3648 inhibitor revealed that miR-3648 inhibited TCF21 protein expression by reduction of its mRNA stability. Further, Kisspeptin 1 (KISS1) was identified as a TCF21 downstream effector responsible for miR-3648-mediated BC invasion and lung metastasis. Collectively, the present results suggest that miR-3648 is overexpressed and plays an oncogenic role in mediation of BC invasion and metastasis through directing the TCF21/KISS1 axis, revealing miR-3648 as a potential biomarker for BC prognosis and a target for BC therapy.

Amorphous silica nanoparticles induce tumorigenesis via regulating ATP5H/SOD1-related oxidative stress, oxidative phosphorylation and EIF4G2/PABPC1-associated translational initiation

Background

Recent studies indicate amorphous silica nanoparticles (SiNPs), one of the widely applied nanomaterials, have potential toxicity in humans and induces cell malignant transformation. However, its carcinogenic mechanisms remain poorly understood. This study’s purpose was to investigate the underlying toxic mechanisms of amorphous SiNPs on human lung epithelial cells model by using microarray data.

Methods

Microarray dataset GSE82062 was collected from Gene Expression Omnibus database, including three repeats of Beas-2B exposed to amorphous SiNPs for 40 passages and three repeats of passage-matched control Beas-2B cells. Differentially expressed genes (DEGs) were identified using linear models for microarray data method. Protein–protein interaction (PPI) network was constructed using data from the STRING database followed by module analysis. The miRwalk2 database was used to predict the underlying target genes of differentially miRNAs. Function enrichment analysis was performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID) online tool.

Results

A total of 323 genes were identified as DEGs, including 280 downregulated (containing 12 pre-miRNAs) and 43 upregulated genes (containing 29 pre-miRNAs). Function enrichment indicated these genes were involved in translational initiation (i.e., eukaryotic translation initiation factor 4 gamma 2 (EIF4G2), poly (A) binding protein cytoplasmic 1 (PABPC1)), response to reactive oxygen species (i.e., superoxide dismutase 1 (SOD1)) and oxidative phosphorylation (i.e., ATP5H). PABPC1 (degree = 15), ATP5H (degree = 11) and SOD1 (degree = 8)] were proved to be hub genes after PPI-module analyses. ATP5H/SOD1 and EIF4G2/PABPC1 were overlapped with the target genes of differentially expressed pre-miR-3648/572/661 and pre-miR-4521.

Conclusions

Amorphous SiNPs may induce tumorigenesis via influencing ATP5H/SOD1-related oxidative stress, oxidative phosphorylation and EIF4G2/PABPC1-associated translational initiation which may be regulated by miR-3648/572/661 and miR-4521, respectively.

MicroRNA-focused CRISPR-Cas9 library screen reveals fitness-associated miRNAs

MicroRNAs (miRNAs) are post-transcriptional gene regulators that play important roles in the control of cell fitness, differentiation, and development. The CRISPR-Cas9 gene-editing system is composed of the Cas9 nuclease in complex with a single guide RNA (sgRNA) and directs DNA cleavage at a predetermined site. Several CRISPR-Cas9 libraries have been constructed for genome-scale knockout screens of protein function; however, few libraries have included miRNA genes. Here we constructed a miRNA-focused CRISPR-Cas9 library that targets 1594 (85%) annotated human miRNA stem-loops. The sgRNAs in our LX-miR library are designed to have high on-target and low off-target activity, and each miRNA is targeted by four to five sgRNAs. We used this sgRNA library to screen for miRNAs that affect cell fitness of HeLa or NCI-N87 cells by monitoring the change in frequency of each sgRNA over time. By considering the expression in the tested cells and the dysregulation of the miRNAs in cancer specimens, we identified five HeLa pro-fitness and cervical cancer up-regulated miRNAs (miR-31-5p, miR-92b-3p, miR-146b-5p, miR-151a-3p, and miR-194-5p). Similarly, we identified six NCI-N87 pro-fitness and gastric cancer up-regulated miRNAs (miR-95-3p, miR-181a-5p, miR-188-5p, miR-196b-5p, miR-584-5p, and miR-1304-3p), as well as three anti-fitness and down-regulated miRNAs (let-7a-3p, miR-100-5p, and miR-149-5p). Some of those miRNAs are known to be oncogenic or tumor-suppressive, but others are novel. Taken together, the LX-miR library is useful for genome-wide unbiased screening to identify miRNAs important for cellular fitness and likely to be useful for other functional screens.

Exosomal miRNAs species in the blood of small cell and non-small cell lung cancer patients

Lung cancer is a devastating disease with overall bleak prognosis. Current methods to diagnose lung cancer are rather invasive and are inadequate to detect the disease at an early stage when treatment is likely to be most effective. In this study, a shotgun sequencing approach was used to study the microRNA (miRNA) cargo of serum-derived exosomes of small cell lung cancer (SCLC) (n=9) and non-small cell lung cancer (NSCLC) (n=11) patients, and healthy controls (n=10). The study has identified 17 miRNA species that are differentially expressed in cancer patients and control subjects. Furthermore, within the patient groups, a set of miRNAs were differentially expressed in exosomal samples obtained before and after chemotherapy treatment. This manuscript demonstrates the potential of exosomal miRNAs for developing noninvasive tests for disease differentiation and treatment monitoring in lung cancer patients.

Effects of miR-340 on hepatocellular carcinoma by targeting the DcR3 gene

In hepatocellular carcinoma (HCC), miR-340 plays a vital role in the regulation of tumor occurrence and deterioration, while DcR3 gene is involved in cancer cell proliferation and apoptosis. This study analyzed miR-340 in the serum of patients with HCC and healthy controls. Then, miR-340, DcR3, TGF-β1 and Smad2 expression were measured in HCC tissues and adjacent parts. Relationship between miR-340 and DcR3 was verified. Effects of miR-340 on human HepG2 cell proliferation and apoptosis were explored. miR-340, DcR3, TGF-β1, Smad2 mRNA and protein expression were also determined after miR-340 transfection. Compared with the control, miR-340 was significantly lower in the serum of the HCC patients (p < 0.01). miR-340 was lower in HCC tissues than in adjacent; however, DcR3, TGF-β1 and Smad2 were higher (p < 0.01). Furthermore, luciferase activity was significantly lower in the cells co-transfected with miR-340 mimics and DcR3-3'UTR-WT (p < 0.01), indicating that DcR3 was a target gene of miR-340. Moreover, decreased expression in DcR3, TGF-β1 and Smad2 was detected after miR-340 overexpression (p < 0.01), thus promoting apoptosis and blocking the proliferation of human HepG2 cells (p < 0.05). Furthermore, overexpression of DcR3 could activate the TGF-β1/Smad2 signal transduction pathway and increase the phosphorylation of Smad2. In conclusion, miR-340 plays a suppressive role in HCC development by targeting DcR3 and silencing the TGF-β1/Smad2 signaling pathway.

Endoplasmic Reticulum Stress Facilitates the Survival and Proliferation of Nucleus Pulposus Cells in TNF-α Stimulus by Activating Unfolded Protein Response

Intervertebral disc (IVD) degeneration is closely related to inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α). The endoplasmic reticulum (ER) serves several important cell functions, which are essential for normal cell metabolism and survival. This study aims to clarify the role of ER stress and unfolded protein response (UPR) in TNF-α-induced biological changes in rat nucleus pulposus cells (NPCs) and IVD degeneration. In our research, rat NPCs were cultured with different concentrations of TNF-α in the presence or absence of ER stress inhibitors. Related genes and proteins were measured by immunofluorescence staining, quantitative real-time PCR, and Western blot analyses to monitor ER stress. Cell proliferation was evaluated by CCK-8 assay and cyclin D1 expression. Apoptosis was detected by flow cytometry and Western blot analyses. Our results showed that TNF-α induced the apoptosis of some NPCs in the early stage and then accelerated the proliferation of surviving cells. In addition, TNF-α stimulus upregulated ER stress markers and initiated UPR. However, these effects could be reversed by inhibitors, thereby reducing cell proliferation and enhancing apoptosis. In conclusion, ER stress reinforces the survival and proliferation of NPCs in TNF-α stimulus by activating UPR signaling, which could be an important therapeutic target in the future.

Comparing two approaches of miR-34a target identification, biotinylated-miRNA pulldown vs miRNA overexpression

microRNAs (miRNAs) are critical regulators of gene expression. For elucidating functional roles of miRNAs, it is critical to identify their direct targets. There are debates about whether pulldown of biotinylated miRNA mimics can be used to identify miRNA targets or not. Here we show that biotin-labelled miR-34a can be loaded to AGO2, and AGO2 immunoprecipitation can pulldown biotinylated miR-34a (Bio-miR pulldown). RNA-sequencing (RNA-seq) of the Bio-miR pulldown RNAs efficiently identified miR-34a mRNA targets, which could be verified with luciferase assays. In contrast to the approach of Bio-miR pulldown, RNA-seq of miR-34a overexpression samples had limited value in identifying direct targets of miR-34a. It seems that pulldown of 3'-Biotin-tagged miRNA can identify bona fide microRNA targets at least for miR-34a.