MicroRNAs as Post-Transcriptional Machines and their Interplay with Cellular Networks

Epigenetic modifications in chronic rhinosinusitis with and without nasal polyps

Chronic rhinosinusitis (CRS) has brought a huge socioeconomic burden. However, its mechanism is still elusive, which may involve genetic, environmental and some other factors. Epigenetic analyses have been conducted to explore the mechanisms underlying CRS. Here, we reviewed the fruits in the epigenetic studies on DNA methylation, histone modification, and non-coding RNA regulation. We concluded that the epigenetic research on CRS has made great breakthroughs, especially in the past 5 years and the field of microRNAs. "Epigenetic therapies" are expected to be designed to treat CRS in the future.

Metabotropic Glutamate Receptor 8 Is Regulated by miR-33a-5p and Functions as an Oncogene in Breast Cancer

It has been reported that glutamate metabotropic receptor 8 (GRM8) is closely implicated in the progression of human neuroblastoma, lung cancer, and glioma, but its role in breast cancer remains unknown. Thus, the present study was performed to uncover it. Immunohistochemistry, real-time PCR (RT-PCR), and western blotting experiments were performed to test GRM8 expression levels in tissues and cells. Cell functions were assessed by Cell Count Kit 8 (CCK-8), flow cytometry, wound healing, transwell chambers, and in vivo xenotransplantation experiments. The relationship between miR-33a-5p and GRM8 was evaluated by luciferase gene reporter and western blotting assay. The results showed that GRM8 expression was increased in breast cancer tissues and cells, which was closely associated with lower overall survival rate. Ectopic expression of GRM8 significantly enhanced cell growth, migration, and invasion and tumorigenesis and repressed cell apoptosis. In addition, GRM8 was under the negative regulation of miR-33a-5p, which was downregulated in breast cancer tissues and served as a tumor suppressor. Moreover, overexpression of GRM8 abrogated the inhibitive role of miR-33a-5p played in breast cancer. Collectively, this study reveals that GRM8 functions as an oncogene in breast cancer and is regulated by miR-33a-5p.

The Roles of Different Stem Cells in Premature Ovarian Failure

Premature ovarian failure (POF) is characterized by amenorrhea, hypergonadotropism and hypoestrogenism before the age of 40, which affects 1% of women in the general population. POF is complex and heterogeneous due to its pathogenetic mechanisms. It is one of the significant causes of female infertility. Although many treatments are available for POF, these therapies are less efficient and trigger many side effects. Therefore, to find effective therapeutics for POF is urgently required. Due to stem cells having self-renewal and regeneration potential, they may be effective for the treatment of ovarian failure and consequently infertility. Recent studies have found that stem cells therapy may be able to restore the ovarian structure and function in animal models of POF and provide an effective treatment method. The present review summarizes the biological roles and the possible signaling mechanisms of the different stem cells in POF ovary. Further study on the precise mechanisms of stem cells on POF may provide novel insights into the female reproduction, which not only enhances the understanding of the physiological roles but also supports effective therapy for recovering ovarian functions against infertility.

Tissue-specific transplantation antigen P35B functions as an oncogene and is regulated by microRNA-125a-5p in lung cancer

Tissue‑specific transplantation antigen P35B (TSTA3) expression is upregulated in esophageal squamous cell carcinoma and breast cancer, and functions as an oncogene in breast cancer. However, the roles and underlying mechanisms of TSTA3 in lung cancer have not been fully elucidated. The current study aimed to reveal the role of TSTA3 in lung cancer and explore whether TSTA3 may be modulated by microRNA (miR)‑125a‑5p to activate β‑catenin signaling. Immunohistochemical staining and western blotting were used to analyze TSTA3 expression in lung cancer tissues and cells. Cell functions were assessed via Cell Counting Kit‑8, flow cytometry, wound‑healing, Transwell and in vivo tumor formation assays. The effect of TSTA3 on the activation of β‑catenin signaling was determined using western blot and immunofluorescence analyses. The association between miR‑125a‑5p and TSTA3 was determined by western blotting and luciferase gene reporter assay. The present study revealed that, compared with normal tissues and cells, TSTA3 expression was significantly increased in lung cancer tissues and cell lines, and high TSTA3 expression predicted a poor prognosis and more malignant clinical features in patients with lung cancer. TSTA3 upregulation significantly enhanced β‑catenin expression and promoted its nuclear accumulation. In addition, TSTA3 expression was negatively regulated by miR‑125a‑5p, which was downregulated in lung cancer. Furthermore, TSTA3 overexpression markedly promoted cell proliferation, migration, invasion and tumorigenesis, and suppressed cell apoptosis. TSTA3 downregulation abolished the effects of miR‑125a‑5p downregulation on promoting lung cancer cell malignant transformation. Overall, the current study demonstrates that TSTA3 is regulated by miR‑125a‑5p and functions as an oncogene in lung cancer via promoting the activation of β‑catenin signaling.

Circular RNA circ_103820 suppresses lung cancer tumorigenesis by sponging miR-200b-3p to release LATS2 and SOCS6

A growing number of circular RNAs (circRNAs) have been identified and verified in several cancers. However, highly efficient therapeutic methods based on circRNAs in lung cancer remain largely unexplored. In the present study, we identified a novel circular RNA, hsa_circ_103820, based on Gene Expression Omnibus (GEO) data. Functionally, overexpression of hsa_circ_103820 showed significant inhibitory effects on the proliferation, migration and invasion of lung cancer cells, and knockdown of hsa_circ_103820 played promoting roles. Regarding the mechanism, we revealed that miR-200b-3p was a direct target of hsa_circ_103820 and that LATS2 and SOCS6 were the downstream target genes of miR-200b-3p. Therefore, we identified a novel potential tumor suppressive function of hsa_circ_103820 in lung cancer.

Non-coding RNAs and the mineralocorticoid receptor in the kidney

The final steps in the Renin-Angiotensin-Aldosterone signaling System (RAAS) involve binding of the corticosteroid hormone, aldosterone to its mineralocorticoid receptor (MR). The bound MR interacts with response elements to induce or repress the transcription of aldosterone-regulated genes. Along with the classic genomic targets of aldosterone that alter mRNA and protein expression, aldosterone also regulates the expression of non-coding RNAs (ncRNAs). Short ncRNAs termed microRNAs (miRs) have been shown to play a role in transducing aldosterone's actions via MR signaling. The role of miRs in homeostatic regulation of aldosterone signaling, and the potential for aldosterone-regulated miRs to act as feedback regulators of MR have been recently reported. In this review, the role of miRs in RAAS signaling and feedback regulation of MR in kidney epithelial cells will be discussed.

Molecular mechanism of Chinese alligator (Alligator sinensis) adapting to hibernation

Hibernation is a physiological state for Chinese alligators to cope with cold weather. In mammals, gene expression changes during hibernation and their regulatory mechanisms have been extensively studied, however, these studies in reptiles are still rare. Here, integrated analysis of messenger RNA (mRNA), microRNA (miRNA), and long noncoding RNA (lncRNA) reveals the molecular mechanisms of the hypothalamus, liver, and skeletal muscle in hibernating and active individuals. During hibernation, the number of genes increased in the hypothalamus, liver, and skeletal muscle was 585, 282, and 297, while the number of genes decreased was 215, 561, and 627, respectively, as compared with active individuals. Through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, the differential expressed genes were mainly enriched in DNA damage repair, biological rhythm, energy metabolism, myoprotein degradation, and other related items and pathways. Besides, 4740 miRNAs were identified in three tissues. Through the comprehensive analysis of miRNA and mRNA abundance profiles, 12,291, 6997, and 8232 miRNA-mRNA pairs all showed a negative correlation in the hypothalamus, liver, and skeletal muscle, respectively. Some miRNA target genes were related tobiological rhythm and energy metabolism, suggesting that miRNA may play an important role in the physiological metabolism of the hibernating adaptability of Chinese alligators. Moreover, 402, 230, and 130 differentially expressed lncRNAs were identified in the hypothalamus, liver, and skeletal muscle, respectively. The targeting relationship of four lncRNA-mRNA pairs were predicted, with the main function of target genes involved in the amino acid transportation. These results are helpful to further understand the molecular regulatory basis of the hibernation adaptation in Chinese alligators.

The Role of Epigenetics in the Chronic Sinusitis with Nasal Polyp

PURPOSE OF REVIEW

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common and heterogeneous inflammatory disease. The underlying epigenetic mechanisms and treatment of CRSwNP are partially understood. Of the different epigenetic changes in CRSwNP, histone deacetylases (HDACs), methylation of DNA, and the levels of miRNA are widely studied. Here, we review the human studies of epigenetic mechanisms in CRSwNP.

RECENT FINDINGS

The promoters of COL18A1, PTGES, PLAT, and TSLP genes are hypermethylated in CRSwNP compared with those of controls, while the promoters of PGDS, ALOX5AP, LTB4R, IL-8, and FZD5 genes are hypomethylated in CRSwNP. Promoter hypermethylation suppresses the gene expression, while promoter hypomethylation increases the gene expression. Studies have shown the elevation in the levels of HDAC2, HDAC4, and H3K4me3 in CRSwNP. In CRSwNP patients, there is also an upregulation of certain miRNAs including miR-125b, miR-155, miR-19a, miR-142-3p, and miR-21 and downregulation of miR-4492. Epigenetics takes part in the immunology of CRSwNP and may give rise to endotypes of CRSwNP. Both HDAC2 and the miRNA including miR-18a, miR-124a, and miR-142-3p may take function in the regulation of glucocorticoid resistance. HDAC inhibitors and KDM2B have shown effectiveness in decreasing nasal polyp, and DNA methyltransferase (DNMT) or HDAC inhibitors may have a potential efficacy for the treatment of CRSwNP. Recent advances in the epigenetics of CRSwNP have led to the identification of several potential therapeutic targets for this disease. The use of epigenetics may provide novel and effective biomarkers and therapies for the treatment of nasal polyp.

The Role of Dynamic miRISC During Neuronal Development

Activity-dependent protein synthesis plays an important role during neuronal development by fine-tuning the formation and function of neuronal circuits. Recent studies have shown that miRNAs are integral to this regulation because of their ability to control protein synthesis in a rapid, specific and potentially reversible manner. miRNA mediated regulation is a multistep process that involves inhibition of translation before degradation of targeted mRNA, which provides the possibility to store and reverse the inhibition at multiple stages. This flexibility is primarily thought to be derived from the composition of miRNA induced silencing complex (miRISC). AGO2 is likely the only obligatory component of miRISC, while multiple RBPs are shown to be associated with this core miRISC to form diverse miRISC complexes. The formation of these heterogeneous miRISC complexes is intricately regulated by various extracellular signals and cell-specific contexts. In this review, we discuss the composition of miRISC and its functions during neuronal development. Neurodevelopment is guided by both internal programs and external cues. Neuronal activity and external signals play an important role in the formation and refining of the neuronal network. miRISC composition and diversity have a critical role at distinct stages of neurodevelopment. Even though there is a good amount of literature available on the role of miRNAs mediated regulation of neuronal development, surprisingly the role of miRISC composition and its functional dynamics in neuronal development is not much discussed. In this article, we review the available literature on the heterogeneity of the neuronal miRISC composition and how this may influence translation regulation in the context of neuronal development.

Impact of Carcinogenic Chromium on the Cellular Response to Proteotoxic Stress

Worldwide, several million workers are employed in the various chromium (Cr) industries. These workers may suffer from a variety of adverse health effects produced by dusts, mists and fumes containing Cr in the hexavalent oxidation state, Cr(VI). Of major importance, occupational exposure to Cr(VI) compounds has been firmly associated with the development of lung cancer. Counterintuitively, Cr(VI) is mostly unreactive towards most biomolecules, including nucleic acids. However, its intracellular reduction produces several species that react extensively with biomolecules. The diversity and chemical versatility of these species add great complexity to the study of the molecular mechanisms underlying Cr(VI) toxicity and carcinogenicity. As a consequence, these mechanisms are still poorly understood, in spite of intensive research efforts. Here, we discuss the impact of Cr(VI) on the stress response—an intricate cellular system against proteotoxic stress which is increasingly viewed as playing a critical role in carcinogenesis. This discussion is preceded by information regarding applications, chemical properties and adverse health effects of Cr(VI). A summary of our current understanding of cancer initiation, promotion and progression is also provided, followed by a brief description of the stress response and its links to cancer and by an overview of potential molecular mechanisms of Cr(VI) carcinogenicity.

Experimental Validation of MicroRNA Targets: Luciferase Reporter Assay

MicroRNAs (miRNAs) are small noncoding RNAs of 22-25 nucleotides that control gene expression at the posttranscriptional level through the degradation of mRNAs or translational repression. In the last 15 years, the study of these small molecules helped elucidate their role in the regulation of many cellular processes and the onset and development of several diseases. Therefore, many computational tools based on algorithms for target prediction have been developed to identify potential miRNA-target interactions. The improvement of experimental approaches to more easily and quickly confirm in silico predictions has become essential for the study of these small RNAs and their molecular functions. In this chapter, we summarized the principal steps of one of the most used techniques for the validation of microRNA targets, the Luciferase assay, thus explaining the underlying principles and the procedures to apply it best.

Experimental Validation of MicroRNA Targets: Analysis of MicroRNA Targets Through Western Blotting

MicroRNAs are a class of small noncoding RNA involved in the mechanism of RNA silencing and regulation of gene expression at a posttranscriptional level. Recently, the discovery of their targets led to the understanding of the molecular role of these small molecules and their involvement in the pathogenesis of numerous diseases, including cancer. Not long ago, the improvement of several informatics tools for microRNA target prediction has supported the experimental research through the selection of potential mRNA as microRNA target candidates. Since the regulation mediated by microRNA affects gene expression at a posttranscriptional level, the analysis of the proteins encoded by the gene targets is essential in understanding the involvement of these small molecules in biological processes and their role in several diseases. In this chapter, we describe the experimental procedure of Western blotting applied to the validation of microRNA targets. Western blotting is one of the most common and largest know technique for protein analysis. This method, coupled with the luciferase assay, represents the standard procedure for the experimental confirmation of microRNA targeting.

Experimental Validation of MicroRNA Targets: Mutagenesis of Binding Regions

MicroRNAs (miRNAs) are small noncoding RNAs that are 22-25 nucleotides in length and control gene expression posttranscriptionally by degrading mRNAs or by translational repression. Many computational tools based on algorithms for target prediction have already been developed to find potential miRNA-target interactions. Since it is essential to confirm in silico predictions, experimental approaches have been improved to validate computationally predicted targets. One of the most widely used techniques is the luciferase assay which allows for the confirmation of specific binding between microRNA and the mRNA target using a reporter plasmid containing the 3' UTR of the target. Through the mutagenesis of this region it is possible to provide indirect evidence of the specific microRNA-mRNA interaction demonstrated using this assay. In this chapter we review the main experimental steps of the 3' UTR mutagenesis and the best way to apply this method to support and complete the luciferase assay procedure.

Pkd1-targeted mutation reveals a role for the Wolffian duct in autosomal dominant polycystic kidney disease

Several life-threatening diseases of the kidney have their origins in mutational events that occur during embryonic development. In this study, we investigate the role of the Wolffian duct (WD), the earliest embryonic epithelial progenitor of renal tubules, in the etiology of autosomal dominant polycystic kidney disease (ADPKD). ADPKD is associated with a germline mutation of one of the two Pkd1 alleles. For the disease to occur, a second event that disrupts the expression of the other inherited Pkd1 allele must occur. We postulated that this secondary event can occur in the pronephric WD. Using Cre-Lox recombination, mice with WD-specific deletion of one or both Pkd1 alleles were generated. Homozygous Pkd1-targeted deletion in WD-derived tissues resulted in mice with large cystic kidneys and serologic evidence of renal failure. In contrast, heterozygous deletion of Pkd1 in the WD led to kidneys that were phenotypically indistinguishable from control in the early postnatal period. High-throughput sequencing, however, revealed underlying gene and microRNA (miRNA) changes in these heterozygous mutant kidneys that suggest a strong predisposition toward developing ADPKD. Bioinformatic analysis of this data demonstrated an upregulation of several miRNAs that have been previously associated with PKD; pathway analysis further demonstrated that the differentially expressed genes in the heterozygous mutant kidneys were overrepresented in signaling pathways associated with maintenance and function of the renal tubular epithelium. These results suggest that the WD may be an early epithelial target for the genetic or molecular signals that can lead to cyst formation in ADPKD.

miR‑767‑5p inhibits glioma proliferation and metastasis by targeting SUZ12

A growing body of evidence implicates aberrant expression of microRNAs (miRNAs) and dysregulation of mRNA translation in the development and growth of cancer cells. However, little is known about the mechanisms of action of miRNAs in glioma, the most common form of adult-onset malignant brain tumor. In the present study, the expression and function of miR-767-5p were examined in human glioblastoma multiforme (GBM) tissue specimens and cell lines. miR-767-5p expression levels were analyzed by quantitative reverse-transcription PCR; cell proliferation was assessed by CCK-8, colony formation and 5-ethynyl-2′-deoxyuridine (EDU) assays; the cell cycle phase and apoptosis were detected by flow cytometry; and cell invasiveness was analyzed using wound healing and Transwell invasion assays. It was revealed found that miR-767-5p was significantly upregulated in GBM tissues (n=18) compared with normal brain tissues (n=8) and in 6 GBM cell lines compared with normal human astrocytes. Ectopic expression of miR-767-5p suppressed proliferation, colony formation, and migration, and promoted cell cycle arrest and apoptosis in GBM cell lines in vitro, and inhibited GBM tumor growth in a mouse xenograft model. Bioinformatics analysis identified the PRC2 component suppressor of zeste-12 (SUZ12) as a putative target of miR-767-5p. Co-transfection of miR-767-5p inhibited the activity of a luciferase reporter construct driven by the wild-type 3′ untranslated region of SUZ12 mRNA, but this was abolished by mutation of the putative miR-767-5p-binding sites. Consistent with the possibility that miR-767-5p acts by regulating SUZ12 expression, it was revealed that the inhibitory effects of miR-767-5p on GBM cell phenotypes were reversed by overexpression of SUZ12. Our results indicated that forced upregulation of miR-767-5p may represent a novel therapeutic strategy for glioma patients by targeting SUZ12.

Exosomal transfer of miR-1238 contributes to temozolomide-resistance in glioblastoma

Background

Although temozolomide (TMZ) resistance is a significant clinical problem in glioblastoma (GBM), its underlying molecular mechanisms are poorly understood. In this study, we identified the role of exosomal microRNAs (miRNAs) from TMZ-resistant cells as important mediators of chemoresistance in GBM cells.

Methods

Exosomes were isolated from TMZ-resistant GBM cells and characterized via scanning electron microscopy (SEM). Expression levels of miR-1238 in GBM cell lines and their exosomes, clinical tissues, and sera were evaluated by RT-qPCR. In vitro and in vivo experiments were performed to elucidate the function of exosomal miR-1238 in TMZ resistance in GBM cells. Co-immunoprecipitation assays and western blot analysis were used to investigate the potential mechanisms of miR-1238/CAV1 that contribute to TMZ resistance.

Findings

MiR-1238 levels were higher in TMZ-resistant GBM cells and their exosomes than in sensitive cells. Higher levels of miR-1238 were found in the sera of GBM patients than in healthy people. The loss of miR-1238 may sensitize resistant GBM cells by directly targeting the CAV1/EGFR pathway. Furthermore, bioactive miR-1238 may be incorporated into the exosomes shed by TMZ-resistant cells and taken up by TMZ-sensitive cells, thus disseminating TMZ resistance.

Interpretation

Our findings establish that miR-1238 plays an important role in mediating the acquired chemoresistance of GBM and that exosomal miR-1238 may confer chemoresistance in the tumour microenvironment. These results suggest that circulating miR-1238 serves as a clinical biomarker and a promising therapeutic target for TMZ resistance in GBM.

Fund

This study was supported by the National Natural Science Foundation of China (No·81402056, 81472362, and 81772951) and the National High Technology Research and Development Program of China (863) (No·2012AA02A508).

Tomato lncRNA23468 functions as a competing endogenous RNA to modulate NBS-LRR genes by decoying miR482b in the tomato-Phytophthora infestans interaction

Our previous studies indicated that tomato miR482b could negatively regulate the resistance of tomato to Phytophthora infestans and the expression of miR482b was decreased after inoculation with P. infestans. However, the mechanism by which the accumulation of miR482b is suppressed remains unclear. In this study, we wrote a program to identify 89 long noncoding RNA (lncRNA)-originated endogenous target mimics (eTMs) for 46 miRNAs from our RNA-Seq data. Three tomato lncRNAs, lncRNA23468, lncRNA01308 and lncRNA13262, contained conserved eTM sites for miR482b. When lncRNA23468 was overexpressed in tomato, miR482b expression was significantly decreased, and the expression of the target genes, NBS-LRRs, was significantly increased, resulting in enhanced resistance to P. infestans. Silencing lncRNA23468 in tomato led to the increased accumulation of miR482b and decreased accumulation of NBS-LRRs, as well as reduced resistance to P. infestans. In addition, the accumulation of both miR482b and NBS-LRRs was not significantly changed in tomato plants that overexpressed lncRNA23468 with a mutated eTM site. Based on the VIGS system, a target gene of miR482b, Solyc02g036270.2, was silenced. The disease symptoms of the VIGS-Solyc02g036270.2 tomato plants were in accordance with those of tomato plants in which lncRNA23468 was silenced after inoculation with P. infestans. More severe disease symptoms were found in the modified plants than in the control plants. Our results demonstrate that lncRNAs functioning as eTMs may modulate the effects of miRNAs in tomato and provide insight into how the lncRNA23468-miR482b-NBS-LRR module regulates tomato resistance to P. infestans.

Regulation of Aldosterone Signaling by MicroRNAs

The mineralocorticoid hormone aldosterone is released by the adrenal glands in a homeostatic mechanism to regulate blood volume. Several cues elicit aldosterone release, and the long-term action of the hormone is to restore blood pressure and/or increase the retrieval of sodium from filtered plasma in the kidney. While the signaling cascade that results in aldosterone release is well studied, the impact of this hormone on tissues and cells in various organ systems is pleotropic. Emerging evidence indicates aldosterone may alter non-coding RNAs (ncRNAs) to integrate the hormonal response, and these ncRNAs may contribute to the heterogeneity of signaling outcomes in aldosterone target tissues. The best studied of the ncRNAs in aldosterone action are the small ncRNAs, microRNAs. MicroRNA expression is regulated by aldosterone stimulation, and microRNAs are able to modulate protein expression at all steps in the renin-angiotensin-aldosterone-signaling system. The discovery and synthesis of microRNAs will be briefly covered followed by a discussion of the reciprocal role of aldosterone/microRNA regulation, including misregulation of microRNA signaling in aldosterone-linked disease states.

MiRNA-139-3p inhibits the proliferation, invasion, and migration of human glioma cells by targeting MDA-9/syntenin

Gliomas are the most common primary malignant brain tumor in adults. Although these tumors are aggressive and frequently lethal, there are currently few therapeutic approaches available to prolong patient survival. MicroRNAs play important roles in regulating the expression of genes that control diverse cellular processes. Here, we investigated the expression and function of miR-139-3p in gliomas using clinical specimens, cultured cells, and a mouse xenograft tumor model. We found that miR-139-3p expression is markedly lower in human glioma tissues than in normal brain tissues. We identified melanoma differentiation-associated gene-9 (MDA-9)/syntenin, an adaptor protein implicated in tumor metastasis, as a novel direct target of miR-139-3p and showed that syntenin mRNA and miR-139-3p levels were inversely correlated in clinical specimens (r = -0.6817, P = 0.0002). Overexpression of miR-139-3p in human glioma cell lines inhibited cell proliferation, migration, and invasion, and these effects were rescued by co-transfection with syntenin. Our results indicate that miR-139-3p plays a significant role in controlling behaviors associated with the malignant progression of gliomas, and we identify the miR-139-3p-syntenin axis as a potential therapeutic target for glioma.

MiR-29a inhibited intestinal epithelial cells autophagy partly by decreasing ATG9A in ulcerative colitis

Ulcerative colitis (UC), with high morbidity has become one of the fastest-growing severe illnesses in the world. Although MiR-29a is highly expressed in the tissues of UC patients, the mechanism of miR-29a involved in the specific pathogenesis of UC is not known. In this study, a GFP-light chain 3 (LC3) immunofluorescence assay was used to observe the formation of the autophagic spot; qRT-PCR and western blotting analyses were carried out to detect the expression of autophagy-related proteins, including BECN1, Autophagy-related gene (ATG)5, ATG16L, and transcription factor EB. The dual-fluorescence reporter assay was used to analyze the direct effect of miR-29a on ATG9A; experimental dextran sulfate sodium-induced colitis in mice was used to establish the UC model. Our studies showed that the overexpression of miR-29a not only suppressed the production of GFP-LC3 autophagy spots but also inhibited the level of LC3II/LC3I and upregulated the expression of P62 in HT29 and HCT116 cells. Moreover, the results showed that miR-29a directly targeted the 3'UTR region of ATG9A mRNA to suppress the activation of HT29 and HCT116 cells' autophagy. Also, overexpression of ATG9A rescued rapamycin-induced autophagy that was inhibited by overexpression of miR-29a. In addition, miR-29a also affected the expression of autophagy-related proteins (BECN1, ATG5, ATG16L1, and transcription factor EB). Notably, miR-29a was upregulated, whereas ATG9A was downregulated in the experimental dextran sulfate sodium-induced colitis in mice. In effect, this study showed that miR-29a inhibits rapamycin-induced intestinal epithelial cells' autophagy partly by decreasing ATG9A in UC. These findings may provide new insights that may help control the inflammation in UC.

Ultrasound‑targeted microbubble destruction‑mediated miR‑205 enhances cisplatin cytotoxicity in prostate cancer cells

MicroRNAs (miRNAs) are non-coding ~20 nucleotides long sequences that function in the initiation and development of a number of cancers. Ultrasound-targeted microbubble destruction (UTMD) is an effective method for microRNA delivery. The aim of the present study was to investigate the potential roles of UTMD-mediated miRNA (miR)-205 delivery in the development of prostate cancer (PCa). In the present study, miR-205 expression was examined by reverse transcription-quantitative polymerase chain reaction assay. miR-205 mimics were transfected into PC-3 cells using the UTMD method, and the PC-3 cells were also treated with cisplatin. Cell proliferation, apoptosis, migration and invasion abilities were detected using Cell Counting kit-8, flow cytometry, wound healing and Transwell assays, respectively. In addition, the protein expression levels of caspase-9, cleaved-caspase 9, cytochrome c (cytoc), epithelial (E)-cadherin, matrix metalloproteinase-9 (MMP-9), phosphorylated (p)-extracellular signal-regulated kinase (ERK) and ERK were measured by western blot analysis. The results of the present study demonstrated that miR-205 expression was low in human PCa cell lines compared with healthy cells and that UTMD-mediated miR-205 delivery inhibited PCa cell proliferation, migration and invasion, and promoted apoptosis modulated by cisplatin compared with UTMD-mediated miR-negative control group and miR-205-treated group. Furthermore, it was demonstrated that UTMD-mediated miR-205 transfection increased the expression of caspase-9, cleaved-caspase 9, cytochrome c and E-cadherin, and decreased the expression of MMP-9 and p-ERK. Therefore, UTMD-mediated miR-205 delivery may be a promising method for the treatment of PCa.

MicroRNA-1231 exerts a tumor suppressor role through regulating the EGFR/PI3K/AKT axis in glioma

PURPOSE

MicroRNAs (miRNAs) have been shown to be involved in the initiation and progression of glioma. However, the underlying molecular mechanisms are still unclear.

METHODS

We performed microarray analysis to evaluate miRNA expression levels in 158 glioma tissue samples, and examined miR-1231 levels in glioma samples and healthy brain tissues using qRT-PCR. In vitro analyses were performed using miR-1231 mimics, inhibitors, and siRNA targeting EGFR. We used flow cytometry, CCK-8 assays, and colony formation assays to examine glioma proliferation and cell cycle analysis. A dual luciferase reporter assay was performed to examine miR-1231 regulation of EGFR, and the effect of upregulated miR-1231 was investigated in a subcutaneous GBM model.

RESULTS

We found that miR-1231 expression was decreased in human glioma tissues and negatively correlated with EGFR levels. Moreover, the downregulation of miR-1231 negatively correlated with the clinical stage of human glioma patients. miR-1231 overexpression dramatically downregulated glioma cell proliferation, and suppressed tumor growth in a nude mouse model. Bioinformatics prediction and a luciferase assay confirmed EGFR as a direct target of miR-1231. EGFR overexpression abrogated the suppressive effect of miR-1231 on the PI3K/AKT pathway and G1 arrest.

CONCLUSIONS

Taken together, these results demonstrated that EGFR is a direct target of miR-1231. Our findings suggest that the miR-1231/EGFR axis may be a helpful future diagnostic target for malignant glioma.

Effective enhancement of resistance to Phytophthora infestans by overexpression of miR172a and b in Solanum lycopersicum

Overexpression of miR172a and b in tomato ( Solanum lycopersicum ) Zaofen No. 2 increased resistance to Phytophthora infestans infection by suppressing of an AP2/ERF transcription factor. The miR172 family has been shown to participate in the growth phase transition, flowering time control, abiotic and biotic stresses by regulating the expression of a small group of AP2/ERF transcription factors. In this study, the precursors of miR172a and b were cloned from tomato, Solanum pimpinellifolium L3708. We used the degradome sequencing to determine the cleavage site of miR172 to a member of the AP2/ERF transcription factor family (Solyc11g072600.1.1). qRT-PCR results showed that the expression of AP2/ERF was negatively correlated with the expression of miR172 in S. pimpinellifolium L3708 infected with Phytophthora infestans. Overexpression of miR172a and b in S. lycopersicum Zaofen No. 2 conferred greater resistance to P. infestans infection, as evidenced by decreased disease index, lesion sizes, and P. infestans abundance. The SOD and POD play important roles in scavenging late massive ROS in plant-pathogen interaction. Malonaldehyde (MDA) is widely recognized as an indicator of lipid peroxidation. Membrane damage in plants can be estimated by measuring leakage of electrolytes, which is evaluated by determining relative electrolyte leakage (REL). Less H₂O₂ and O₂^-, higher activities of POD and SOD, less MDA content and REL, and higher chlorophyll content and photosynthetic rate were also shown in transgenic plants after inoculation with P. infestans. Our results constitute the first step towards further investigations into the biological function and molecular mechanism of miR172-mediated silencing of AP2/ERF transcription factors in S. lycopersicum-P. infestans interaction and provide a candidate gene for breeding to enhance biotic stress-resistance in S. lycopersicum.

Downregulation of miR‑205 is associated with glioblastoma cell migration, invasion, and the epithelial-mesenchymal transition, by targeting ZEB1 via the Akt/mTOR signaling pathway

Glioblastoma (GBM) is the most common type of malignant brain tumor. In spite of recent advancements in surgical techniques, chemotherapy, and radiation therapy, patients with GBM often face a dire prognosis. MicroRNAs have been shown to modulate the aggressiveness of various cancers, and have emerged as possible therapeutic agents for the management of GBM. miR‑205 is dysregulated in glioma and act as a prognostic indicator. However, the role of miR‑205 in the development of GBM has not been elucidated. To better understand the pathogenesis of GBM, we examine the biological significance and molecular mechanisms of miR‑205 in GBM cells. Zinc finger E-box binding homeobox 1 (ZEB1) has been shown to regulate the epithelial-mesenchymal transition (EMT), which is strongly associated with GBM malignancy. In the present study, we show miR‑205 expression is reduced in GBM tissues and cell lines, and ZEB1 expression is inversely correlated with miR‑205 expression. We also show ZEB1 is a downstream target of miR‑205 and the Akt/mTOR signaling pathway is activated when miR‑205 interacts with ZEB1. Increased activity of miR‑205 in GBM cells significantly inhibits migration and invasion, and prevents EMT. Furthermore, overexpression of ZEB1 partially abolishes these inhibitory effects of miR‑205. We show that miR‑205 negatively regulates the expression of ZEB1 in GBM, inhibits cell migration and invasion, and prevents EMT, at least in part through the inhibition of the activation of the Akt/mTOR signaling pathway. Our results indicate miR‑205 may be an efficacious therapeutic agent in the treatment of GBM.

Overexpression of miR-21 in stem cells improves ovarian structure and function in rats with chemotherapy-induced ovarian damage by targeting PDCD4 and PTEN to inhibit granulosa cell apoptosis

BACKGROUND

Chemotherapy-induced premature ovarian failure (POF) is a severe complication affecting tumor patients at a childbearing age. Mesenchymal stem cells (MSCs) can partially restore the ovarian structure and function damaged by chemotherapy. miR-21 is a microRNA that can regulate cell apoptosis. This study discusses the repair effect and mechanism of MSCs overexpressing miR-21 on chemotherapy-induced POF.

METHODS

Rat MSCs and granulosa cells (GCs) were isolated in vitro. MSCs were transfected with miR-21 lentiviral vector (LV-miR-21) to obtain MSCs stably expressing miR-21 (miR-21-MSCs). The microenvironment of an ovary receiving chemotherapy was mimicked by adding phosphamide mustard (PM) into the cellular culture medium. The apoptosis rate and the mRNA and protein expression of target genes PTEN and PDCD4 were detected in MSCs. Apoptosis was induced by adding PM into the culture medium for GCs, which were cocultured with miR-21-MSCs. The apoptosis rate and the mRNA and protein expression of PTEN and PDCD4 were detected. The chemotherapy-induced POF model was built into rats by intraperitoneal cyclophosphamide injection. miR-21-MSCs were transplanted into the bilateral ovary. The rats were sacrificed at 15, 30, 45, and 60 days after the last injection. The ovarian weights, follicle count, estrous cycle, and sex hormone levels (estradiol (E2) and follicle-stimulating hormone (FSH)) were detected. Apoptosis of GCs was determined by TUNEL assay. The miR-21 and mRNA and protein expression of PTEN and PDCD4 were determined.

RESULTS

The apoptosis decreased in MSCs transfected with miR-21. The mRNA and protein expression of target genes PTEN and PDCD4 was downregulated. GCs cocultured with miR-21-MSCs showed a decreased apoptosis, an upregulation of miR-21, and a downregulation of PTEN and PDCD4. Following the injection of miR-21-MSCs, the ovarian weight and follicle counts increased; E₂ levels increased while FSH levels decreased, with less severe apoptosis of GCs. The miR-21 expression in the ovaries was upregulated, while the mRNA expression and protein expression of PTEN and PDCD4 were downregulated.

CONCLUSIONS

Overexpression of miR-21 in MSCs promoted efficacy against chemotherapy-induced POF and its improvement of the repair effect was related to the inhibition of GC apoptosis by targeting PTEN and PDCD4.

MicroRNA 26a (miR-26a)/KLF4 and CREB-C/EBPβ regulate innate immune signaling, the polarization of macrophages and the trafficking of Mycobacterium tuberculosis to lysosomes during infection

For efficient clearance of Mycobacterium tuberculosis (Mtb), macrophages tilt towards M1 polarization leading to the activation of transcription factors associated with the production of antibacterial effector molecules such as nitric oxide (NO) and proinflammatory cytokines such as interleukin 1 β (IL-1β) and tumor necrosis factor α (TNF-α). At the same time, resolution of inflammation is associated with M2 polarization with increased production of arginase and cytokines such as IL-10. The transcriptional and post-transcriptional mechanisms that govern the balance between M1 and M2 polarization, and bacteria-containing processes such as autophagy and trafficking of Mtb to lysosomes, are incompletely understood. Here we report for the first time, that the transcription factor KLF4 is targeted by microRNA-26a (miR-26a). During Mtb infection, downregulation of miR-26a (observed both ex vivo and in vivo) facilitates upregulation of KLF4 which in turn favors increased arginase and decreased iNOS activity. We further demonstrate that KLF4 prevents trafficking of Mtb to lysosomes. The CREB-C/EBPβ signaling axis also favors M2 polarization. Downregulation of miR-26a and upregulation of C/ebpbeta were observed both in infected macrophages as well as in infected mice. Knockdown of C/ebpbeta repressed the expression of selected M2 markers such as Il10 and Irf4 in infected macrophages. The importance of these pathways is substantiated by observations that expression of miR-26a mimic or knockdown of Klf4 or Creb or C/ebpbeta, attenuated the survival of Mtb in macrophages. Taken together, our results attribute crucial roles for the miR-26a/KLF4 and CREB-C/EBPβsignaling pathways in regulating the survival of Mtb in macrophages. These studies expand our understanding of how Mtb hijacks host signaling pathways to survive in macrophages, and open up new exploratory avenues for host-targeted interventions.

Characterizing isomiR variants within the microRNA-34/449 family

miR‐34/449 microRNAs are conserved regulators of multiciliated cell differentiation. Here, we evidence and characterize expression of two isomiR variant sequences from the miR‐34/449 family in human airway epithelial cells. These isomiRs differ from their canonical counterparts miR‐34b and miR‐449c by one supplemental uridine at their 5′‐end, leading to a one‐base shift in their seed region. Overexpression of canonical miR‐34/449 or 5′‐isomiR‐34/449 induces distinct gene expression profiles and biological effects. However, some target transcripts and functional activities are shared by both canonical microRNAs and isomiRs. Indeed, both repress important targets that result in cell cycle blockage and Notch pathway inhibition. Our findings suggest that 5′‐isomiR‐34/449 may represent additional mechanisms by which miR‐34/449 family finely controls several pathways to drive multiciliogenesis.

miR-423-5p contributes to a malignant phenotype and temozolomide chemoresistance in glioblastomas

BACKGROUND

Gliomas are based on a genetic abnormality and present with a dismal prognosis. MicroRNAs (miRNAs) are considered to be important mediators of gene expression in glioma tissues.

METHODS

Real-time PCR was used to analyze the expression of microRNA-423-5p (miR-423-5p) in human glioma samples and normal brain tissue. Apoptosis, cell cycle, proliferation, immunostaining, transwell, in vitro 2D and 3D migration, and chemosensitivity assays were performed to assess the phenotypic changes in glioma cells overexpressing miRNA-423-5p. Western blotting was used to determine the expression of inhibitor of growth 4 (ING-4)in glioma tissues, and a luciferase reporter assay was conducted to confirm whether ING-4 is a direct target of miR-423-5p. Western blotting was used to identify the potential signaling pathways that are affected in glioma cell growth by miR-423-5p. Xenograft tumors were examined in vivo for the carcinogenic effects of miR-423-5p in glioma tissues.

RESULTS

We first reported that miR-423-5p expression was increased in gliomas and was a potential tumor promoter via targeting ING-4. The overexpression of miR-423-5p resulted in upregulation of important signaling molecules such as p-AKT and p-ERK1/2. In clinical samples, miR-423-5p was dysregulated, and a corresponding alteration in ING-4 expression was observed (P = .0207). Furthermore, the overexpression of miR-423-5p strengthened glioma cell proliferation, angiogenesis, and invasion. Finally, miR-423-5p overexpression also strengthened GBM neurosphere formation and rendered glioma cells resistant to temozolomide (TMZ).

CONCLUSION

This study establishes that miR-423-5p functions as an oncogene in glioma tissues by suppressing ING-4 and suggests that it has therapeutic potential for glioma.

Evaluation of microRNAs-29a, 92a and 145 in colorectal carcinoma as candidate diagnostic markers: An Egyptian pilot study

BACKGROUND

Colorectal cancer (CRC) is one of the most common malignant neoplasms in Egypt, and interestingly in young age. Adenomatous polyps and inflammatory bowel diseases (IBD) are considered the commonest pre-malignant lesions for CRC. A possible diagnostic role for different microRNAs on CRC has been suggested by numerous studies.

AIM OF WORK

To assess the serum expression of 3 microRNA markers (miR-29a, miR-92a and miR-145) in pre-malignant and malignant colorectal lesions.

PATIENTS AND METHODS

The 60 patients studied were divided into 4 groups: CRC group (25 patients), IBD group (11 patients), adenomatous polyps group (14 patients) and control group (10 patients). The serum expression of the 3 markers (miR-29a, miR-92a and miR-145) has been assessed by RT-PCR.

RESULTS

All CRCs were sporadic cases. Significant downregulation of miR-145 in CRC group was reported at all levels, i.e. when compared to normal, among the 3 studied groups, and when compared between CRC and non-CRC groups. Significant upregulation of miR-29a in CRC was reported when compared to normal, but no significant difference existed either among the 3 studied groups or between CRC and the other 2 groups. All 3 miRNAs studied were positively inter-correlated.

CONCLUSIONS

miR-145 may be considered a promising non-invasive reliable diagnostic marker in CRC. Extended studies are needed to ascertain the diagnostic role of miRNAs in CRC.

Differential miRNA Expression in Cells and Matrix Vesicles in Vascular Smooth Muscle Cells from Rats with Kidney Disease

Vascular calcification is a complex process and has been associated with aging, diabetes, chronic kidney disease (CKD). Although there have been several studies that examine the role of miRNAs (miRs) in bone osteogenesis, little is known about the role of miRs in vascular calcification and their role in the pathogenesis of vascular abnormalities. Matrix vesicles (MV) are known to play in important role in initiating vascular smooth muscle cell (VSMC) calcification. In the present study, we performed miRNA microarray analysis to identify the dysregulated miRs between MV and VSMC derived from CKD rats to understand the role of post-transcriptional regulatory networks governed by these miRNAs in vascular calcification and to uncover the differential miRNA content of MV. The percentage of miRNA to total RNA was increased in MV compared to VSMC. Comparison of expression profiles of miRNA by microarray demonstrated 33 miRs to be differentially expressed with the majority (~ 57%) of them down-regulated. Target genes controlled by differentially expressed miRNAs were identified utilizing two different complementary computational approaches Miranda and Targetscan to understand the functions and pathways that may be affected due to the production of MV from calcifying VSMC thereby contributing to the regulation of genes by miRs. We found several processes including vascular smooth muscle contraction, response to hypoxia and regulation of muscle cell differentiation to be enriched. Signaling pathways identified included MAP-kinase and wnt signaling that have previously been shown to be important in vascular calcification. In conclusion, our results demonstrate that miRs are concentrated in MV from calcifying VSMC, and that important functions and pathways are affected by the miRs dysregulation between calcifying VSMC and the MV they produce. This suggests that miRs may play a very important regulatory role in vascular calcification in CKD by controlling an extensive network of post-transcriptional targets.

High-throughput sequencing reveals differential expression of miRNAs in tomato inoculated with Phytophthora infestans

The characterization and compare expression profiling of the miRNA transcriptome lay a solid foundation for unraveling the complex miRNA-mediated regulatory network in tomato resistance mechanisms against LB. MicroRNAs (miRNAs) are a class of small endogenous non-coding RNAs with 20-24 nt. They have been identified in many plants with their diverse regulatory roles in biotic stresses. The knowledge, that miRNAs regulate late blight (LB), caused by Phytophthora infestans, is rather limited. In this study, we used miRNA-Seq to investigate the miRNA expression difference between the tomatoes treated with and without P. infestans. A total of 42,714,516 raw reads were generated from two small RNA libraries by high-throughput sequencing. Finally, 207 known miRNAs and 67 new miRNAs were obtained. The differential expression profile of miRNAs in tomato was further analyzed with twofold change (P value ≤0.01). A total of 70 miRNAs were manifested to change significantly in samples treated with P. infestans, including 50 down-regulated miRNAs and 20 up-regulated miRNAs. Moreover, a total of 73 target genes were acquired for 28 differentially expressed miRNAs by psRNATarget analysis. By enrichment pathway analysis of target genes, plant-pathogen interaction was the most highly relevant pathway which played an important role in disease defense. In addition, 30 miRNAs were selected for qRT-PCR to validate their expression patterns. The expression patterns for targets of miR6027, miR5300, miR476b, miR159a, miR164a and miRn13 were selectively examined, and the results showed that there was a negative correlation on the expression patterns between miRNAs and their targets. The targets have previously been reported to be related with plant immune and involved in plant-pathogen interaction pathway in this study, suggesting these miRNAs might act as regulators in process of tomato resistance against P. infestans. These discoveries will provide us useful information to explain tomato resistance mechanisms against LB.

MicroRNAs enrichment in GWAS of complex human phenotypes

BACKGROUND

The genotype information carried by Genome-wide association studies (GWAS) seems to have the potential to explain more of the 'missing heritability' of complex human phenotypes, given improved statistical approaches. Several lines of evidence support the involvement of microRNA (miRNA) and other non-coding RNA in complex human traits and diseases. We employed a novel, genetic annotation-informed enrichment method for GWAS that captures more polygenic effects than standard GWAS analysis, to investigate if miRNA-tagging Single Nucleotide Polymorphisms (SNPs) are enriched of associations with 15 complex human phenotypes. We then leveraged the enrichment using a conditional False Discovery Rate (condFDR) approach to assess any improvement in the detection of individual miRNA SNPs associated with the disorders.

RESULTS

We found SNPs tagging miRNA transcription regions to be significantly enriched of associations with 10 of 15 phenotypes. The enrichment remained significant after controlling for affiliation to other genomic categories, and was confirmed by replication. Albeit only nominally significant, enrichment was found also in miRNA binding sites for 10 phenotypes out of 15. Leveraging the enrichment in the condFDR framework, we observed a 2-4-fold increase in discovery of SNPs tagging miRNA regions.

CONCLUSIONS

Our results suggest that miRNAs play an important role in the polygenic architecture of complex human disorders and traits, and therefore that miRNAs are a genomic category that can and should be used to improve gene discovery.

Transcript and protein expression decoupling reveals RNA binding proteins and miRNAs as potential modulators of human aging

BACKGROUND

In studies of development and aging, the expression of many genes has been shown to undergo drastic changes at mRNA and protein levels. The connection between mRNA and protein expression level changes, as well as the role of posttranscriptional regulation in controlling expression level changes in postnatal development and aging, remains largely unexplored.

RESULTS

Here, we survey mRNA and protein expression changes in the prefrontal cortex of humans and rhesus macaques over developmental and aging intervals of both species' lifespans. We find substantial decoupling of mRNA and protein expression levels in aging, but not in development. Genes showing increased mRNA/protein disparity in primate brain aging form expression patterns conserved between humans and macaques and are enriched in specific functions involving mammalian target of rapamycin (mTOR) signaling, mitochondrial function and neurodegeneration. Mechanistically, aging-dependent mRNA/protein expression decoupling could be linked to a specific set of RNA binding proteins and, to a lesser extent, to specific microRNAs.

CONCLUSIONS

Increased decoupling of mRNA and protein expression profiles observed in human and macaque brain aging results in specific co-expression profiles composed of genes with shared functions and shared regulatory signals linked to specific posttranscriptional regulators. Genes targeted and predicted to be targeted by the aging-dependent posttranscriptional regulation are associated with biological processes known to play important roles in aging and lifespan extension. These results indicate the potential importance of posttranscriptional regulation in modulating aging-dependent changes in humans and other species.

MicroRNAs and the regulation of aldosterone signaling in the kidney

The role of small noncoding RNAs, termed microRNAs (miRs), in development and disease has been recognized for many years. The number of miRs and regulated targets that reinforce a role for miRs in human disease and disease progression is ever-increasing. However, less is known about the involvement of miRs in steady-state, nondisease homeostatic pathways. In the kidney, much of the regulated ion transport is under the control of hormonal signaling. Evidence is emerging that miRs are involved in the hormonal regulation of kidney function and, particularly, in ion transport. In this short review, the production and intra- and extracellular signaling of miRs and the involvement of miRs in kidney disease are discussed. The discussion also focuses on the role of these small biological molecules in the homeostatic control of ion transport in the kidney. MiR regulation of and by corticosteroid hormones, in particular the mineralocorticoid hormone aldosterone, is considered. While information about the role of aldosterone-regulated miRs in the kidney is limited, an increase in the research in this area will undoubtedly highlight the involvement of miRs as central mediators of hormonal signaling in normal physiology.

A systems approach to drug discovery in Alzheimer's disease

In the articles included in this volume, one feels a strong frustration among the writers with the slow course of therapeutics development for Alzheimer's disease and with the clinical failure of targeted therapeutic agents despite substantial progress in our understanding of the biology and biochemistry of the disease.

Control of oncogenic miRNA function by light-activated miRNA antagomirs

MicroRNAs (miRNAs) are single stranded noncoding RNAs of approximately 22 nucleotides that act as posttranscriptional gene regulators by binding partially complementary sequences in the 3' untranslated region (3'-UTR) of target messenger RNAs (mRNAs). MicroRNAs regulate many biological processes including embryonal development, differentiation, apoptosis, and proliferation and the targets of miRNAs range from signalling proteins and transcription factors to RNA binding proteins. Recently, variations in the expression of certain miRNAs have been linked to a variety of human diseases including cancer and viral infections, validating miRNAs as potential targets for drug discovery. Several tools have been developed to control the function of individual miRNAs and have been applied to study their biological role and therapeutic potential; however, common methods lack a precise level of control that allows for the study of miRNA function with high spatial and temporal resolution. Toward this goal, a light-activated miRNA antagomir for mature miR-21 was developed through the site-specific installation of caging groups on the bases of selected nucleotides. Installation of caged nucleotides led to complete inhibition of the antagomir-miRNA hybridization and inactivation of antagomir function. The miRNA-inhibitory activity of the caged antagomirs was fully restored upon decaging through a brief UV irradiation. The synthesized antagomir was applied to the photochemical regulation of miR-21 function in mammalian cells. Moreover, spatial and temporal control over antagomir activity and thus miR-21 function was obtained in mammalian cells. The presented approach enables the precise regulation of miRNA function with unprecedented spatial and temporal resolution using UV irradiation and can be readily extended to any miRNA of interest.

Hypoxia-induced autophagy reduces radiosensitivity by the HIF-1α/miR-210/Bcl-2 pathway in colon cancer cells

Autophagy is an evolutionarily conserved cellular response to conditions of stress such as hypoxia, which induce radioresistance in cancer cells. We studied the mechanism of action of hypoxia on autophagy and radiosensitivity in colon cancer cells. In the human colon cancer cell lines SW480 and SW620, autophagosomes were analyzed to evaluate autophagy by flow cytometry. The expression of hypoxia inducible factor-1α (HIF-1α), Bcl-2, and miR-210 was detected by western blotting and quantitative real-time polymerase chain reaction (PCR). HIF-1α and miR-210 inhibition was induced by siRNA transfections. Apoptosis detection and colony assays were performed to determine radiosensitivity. HIF-1α and miR-210 showed a significant increase under hypoxic condition. The inhibition of HIF-1α decreased miR-210 expression and autophagy. Silencing of miR-210 upregulated Bcl-2 expression and reduced the survival fraction of colon cancer cells after radiation treatment. Under hypoxia, HIF-1α induces miRNA-210 which in turn enhances autophagy and reduces radiosensitivity by downregulating Bcl-2 expression in colon cancer cells. Our results imply that autophagy contributes to the reduction of radiosensitivity in hypoxic environment, and the process is mediated through the HIF-1α/miR-210/Bcl-2 pathway in human colon cancer cells.

Double-negative feedback loop between ZEB2 and miR-145 regulates epithelial-mesenchymal transition and stem cell properties in prostate cancer cells

The invasion and metastasis of tumors are triggered by an epithelial to mesenchymal transition (EMT), which is regulated by microRNAs (miRNAs). EMT also promotes malignant tumor progression and the maintenance of the stem cell property, which endows cancer cells with the capabilities of self-renewal and immortalized proliferation. The transcriptional repressor zinc-finger E-box binding homeobox 2 (ZEB2), as an EMT activator, might be an important promoter of metastasis in some tumors. Here, we report that ZEB2 directly represses the transcription of miR-145, which is a strong repressor of EMT. In turn, ZEB2 is also a direct target of miR-145. Further, our findings show that the downregulation of ZEB2 not only represses invasion, migration, EMT, and the stemness of prostate cancer (PCa) cells, but also suppresses the capability of PC-3 cells to invade bone in vivo. Importantly, the expression level of ZEB2 as revealed by immunohistochemical analysis is positively correlated to bone metastasis, the serum free PSA level, the total PSA level, and the Gleason score in PCa patients and is negatively correlated with miR-145 expression in primary PCa specimens. Thus, our findings demonstrate a double-negative feedback loop between ZEB2 and miR-145 and indicate that the ZEB2/miR-145 double-negative feedback loop plays a significant role in the control of EMT and stem cell properties during the bone metastasis of PCa cells. These results suggest that the double-negative feedback loop between ZEB2 and miR-145 contributes to PCa progression and metastasis and might have therapeutic relevance for the bone metastasis of PCa.

RP5-833A20.1/miR-382-5p/NFIA-dependent signal transduction pathway contributes to the regulation of cholesterol homeostasis and inflammatory reaction

OBJECTIVE

Cardiovascular disease caused by atherosclerosis is the number one cause of death in Western countries and threatens to become the major cause of morbidity and mortality worldwide. Long noncoding RNAs are emerging as new players in gene regulation, but how long noncoding RNAs operate in the development of atherosclerosis remains unclear.

APPROACH AND RESULTS

Using microarray analysis, we found that long noncoding RNA RP5-833A20.1 expression was upregulated, whereas nuclear factor IA (NFIA) expression was downregulated in human acute monocytic leukemia macrophage-derived foam cells. Moreover, we showed that long noncoding RNA RP5-833A20.1 may decreases NFIA expression by inducing hsa-miR-382-5p expression in vitro. We found that the RP5-833A20.1/hsa-miR-382-5p/NFIA pathway is essential to the regulation of cholesterol homeostasis and inflammatory responses in human acute monocytic leukemia macrophages. Lentivirus-mediated NFIA overexpression increased high-density lipoprotein cholesterol circulation, reduced low-density lipoprotein cholesterol, and very-low-density lipoprotein cholesterol circulation, decreased circulation of inflammatory cytokines, including interleukin-1β, interleukin-6, tumor necrosis factor-α, and C-reactive protein, enhanced reverse cholesterol transport, and promoted regression of atherosclerosis in apolipoprotein E-deficient mice.

CONCLUSIONS

Our findings indicated that the RP5-833A20.1/miR-382-5p/NFIA pathway was essential to the regulation of cholesterol homeostasis and inflammatory reactions and suggested that NFIA may represent a therapeutic target to ameliorate cardiovascular disease.

Two miRNA clusters, miR-34b/c and miR-449, are essential for normal brain development, motile ciliogenesis, and spermatogenesis

Ablation of a single miRNA gene rarely leads to a discernable developmental phenotype in mice, in some cases because of compensatory effects by other functionally related miRNAs. Here, we report that simultaneous inactivation of two functionally related miRNA clusters (miR-34b/c and miR-449) encoding five miRNAs (miR-34b, miR-34c, miR-449a, miR-449b, and miR-449c) led to sexually dimorphic, partial perinatal lethality, growth retardation, and infertility. These developmental defects correlated with the dysregulation of ∼ 240 target genes, which are mainly involved in three major cellular functions, including cell-fate control, brain development and microtubule dynamics. Our data demonstrate an essential role of a miRNA family in brain development, motile ciliogenesis, and spermatogenesis.

Cellular microRNA sensors based on luciferase reporters

Recently, microRNAs (miRNAs) have been linked to a variety of human diseases including cancer and viral infections. Small molecule modifiers of miRNAs could represent new therapeutic agents and be used as tools for elucidating the biological roles of miRNAs. In order to identify small molecule modifiers of miRNAs, functional assays for specific miRNAs must be developed and optimized. Here, we report the construction of a luciferase reporter assay for miRNA miR-122 function and the development of a stable Huh7 cell line that can be used for high-throughput screening of small molecule miR-122 inhibitors. The steps described here can be applied not only to Huh7 cells and miR-122 but also to virtually any cell line and miRNA combination.

High-resolution profiling of novel transcribed regions during rat spermatogenesis

Mammalian spermatogenesis is a complex and highly orchestrated combination of processes in which male germline proliferation and differentiation result in the production of mature spermatozoa. If recent genome-wide studies have contributed to the in-depth analysis of the male germline protein-encoding transcriptome, little effort has yet been devoted to the systematic identification of novel unannotated transcribed regions expressed during mammalian spermatogenesis. We report high-resolution expression profiling of male germ cells in rat, using next-generation sequencing technology and highly enriched testicular cell populations. Among 20 424 high-confidence transcripts reconstructed, we defined a stringent set of 1419 long multi-exonic unannotated transcripts expressed in the testis (testis-expressed unannotated transcripts [TUTs]). TUTs were divided into 7 groups with different expression patterns. Most TUTs share many of the characteristics of vertebrate long noncoding RNAs (lncRNAs). We also markedly reinforced the finding that TUTs and known lncRNAs accumulate during the meiotic and postmeiotic stages of spermatogenesis in mammals and that X-linked meiotic TUTs do not escape the silencing effects of meiotic sex chromosome inactivation. Importantly, we discovered that TUTs and known lncRNAs with a peak expression during meiosis define a distinct class of noncoding transcripts that exhibit exons twice as long as those of other transcripts. Our study provides new insights in transcriptional profiling of the male germline and represents a high-quality resource for novel loci expressed during spermatogenesis that significantly contributes to rat genome annotation.

MicroRNA-21 is a novel promising target in cancer radiation therapy

MicroRNAs (miRNAs) represent an important nonprotein part of the human genome in tumor biology. Among the several types of miRNAs, microRNA-21 (miR-21) is dysregulated in several types of cancer and plays a key role in carcinogenesis, recurrence, and metastasis. Thus, it can be a potential target for cancer therapy including radiation therapy. In this review, we focus on miR-21, which has been identified in human cancer tissues, to suggest reasonable strategies for future research. miR-21 may have an influence on cell cycle, DNA damage repair, apoptosis, autophagy, and hypoxia of cancer during irradiation. We review the use of miR-21 in cancer radiation therapy and describe the known functions and possible underlying molecular mechanisms of miR-21 in radiosensitivity and radioresistance. Furthermore, the current and potential future applications of miR-21 in cancer radiation therapy are also discussed.