Role of microRNA-30c in lipid metabolism, adipogenesis, cardiac remodeling and cancer

Advances in the regulation of adipogenesis and lipid metabolism by exosomal ncRNAs and their role in related metabolic diseases

Exosomes are membrane-bound extracellular vesicles released following the fusion of multivesicular bodies (MVBs) with the cell membrane. Exosomes transport diverse molecules, including proteins, lipids, DNA and RNA, and regulate distant intercellular communication. Noncoding RNA (ncRNAs) carried by exosomes regulate cell-cell communication in tissues, including adipose tissue. This review summarizes the action mechanisms of ncRNAs carried by exosomes on adipocyte differentiation and modulation of adipogenesis by exosomal ncRNAs. This study aims to provide valuable insights for developing novel therapeutics.

Adipocyte-derived exosomal miR-30c-5p promotes ovarian angiogenesis in polycystic ovary syndrome via the SOCS3/STAT3/VEGFA pathway

Polycystic ovary syndrome (PCOS) is a systemic endocrine disease affecting women's reproductive health. Ovarian angiogenesis in PCOS patients is abnormal, manifested by increased ovarian stromal vascularization and upregulated proangiogenic factors such as vascular endothelial growth factor (VEGF). However, the specific mechanisms underlying these changes in PCOS remain unknown. In this study, we induced the adipogenic differentiation in preadipocyte 3T3-L1 cells and found that adipocyte-derived exosomes promoted proliferation, migration, tube formation, and VEGFA expression in human ovarian microvascular endothelial cells (HOMECs) by delivering miR-30c-5p. Mechanistically, dual luciferase reporter assay demonstrated that miR-30c-5p directly targeted the 3'- untranslated region (UTR) of suppressor of cytokine signaling 3 (SOCS3) mRNA. In addition, adipocyte-derived exosomal miR-30c-5p activated signal transducer and activator of transcription 3 (STAT3)/VEGFA pathway in HOMECs via targeting SOCS3. In vivo experiments indicated that tail vein injection of adipocyte-derived exosomes exacerbated endocrine and metabolic disorders and ovarian angiogenesis in mice with PCOS via miR-30c-5p. Taken together, the study revealed that adipocyte-derived exosomal miR-30c-5p promotes ovarian angiogenesis via the SOCS3/STAT3/VEGFA pathway, thereby participating in the development of PCOS.

MALAT1-miR-30c-5p-CTGF/ATG5 axis regulates silica-induced experimental silicosis by mediating EMT in alveolar epithelial cells

Epithelial-mesenchymal transdifferentiation of alveolar type Ⅱ epithelial cells is a vital source of pulmonary myofibroblasts, and myofibroblasts formation is recognized as an important phase in the pathological process of silicosis. miR-30c-5p has been determined to be relevant in the activation of the epithelial-mesenchymal transition (EMT) in numerous disease processes. However, elucidating the role played by miR-30c-5p in the silicosis-associated EMT process remains a great challenge. In this work, based on the establishment of mouse silicosis and A549 cells EMT models, miR-30c-5p was interfered with in vivo and in vitro models to reveal its effects on EMT and autophagy. Moreover, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), connective tissue growth factor (CTGF), autophagy-related gene 5 (ATG5), and autophagy were further interfered with in the A549 cells models to uncover the possible molecular mechanism through which miR-30c-5p inhibits silicosis associated EMT. The results demonstrated the targeted binding of miR-30c-5p to CTGF, ATG5, and MALAT1, and showed that miR-30c-5p could prevent EMT in lung epithelial cells by acting on CTGF and ATG5-associated autophagy, thereby inhibiting the silicosis fibrosis process. Furthermore, we also found that lncRNA MALAT1 might competitively absorb miR-30c-5p and affect the EMT of lung epithelial cells. In a word, interfering with miR-30c-5p and its related molecules (MALAT1, CTGF, and ATG5-associated autophagy) may provide a reference point for the application of silicosis intervention-related targets.

Emerging Role of MicroRNA-30c in Neurological Disorders

MicroRNAs (miRNAs or miRs) are a class of small non-coding RNAs that negatively regulate the expression of target genes by interacting with 3' untranslated regions of target mRNAs to induce mRNA degradation and translational repression. The miR-30 family members are involved in the development of many tissues and organs and participate in the pathogenesis of human diseases. As a key member of the miR-30 family, miR-30c has been implicated in neurological disorders such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and stroke. Mechanistically, miR-30c may act as a multi-functional regulator of different pathogenic processes such as autophagy, apoptosis, endoplasmic reticulum stress, inflammation, oxidative stress, thrombosis, and neurovascular function, thereby contributing to different disease states. Here, we review and discuss the biogenesis, gene regulation, and the role and mechanisms of action of miR-30c in several neurological disorders and therapeutic potential in clinics.

Novel efficacious microRNA-30c analogs reduce apolipoprotein B secretion in human hepatoma and primary hepatocyte cells

High plasma lipid levels have been demonstrated to increase cardiovascular disease risk. Despite advances in treatments to decrease plasma lipids, additional therapeutics are still needed because many people are intolerant or nonresponsive to these therapies. We previously showed that increasing cellular levels of microRNA-30c (miR-30c) using viral vectors or liposomes reduces plasma lipids and atherosclerosis. In this study, we aimed to synthesize potent miR-30c analogs that can be delivered to hepatoma cells without the aid of viral vectors and lipid emulsions. We hypothesized that modification of the passenger strand of miR-30c would increase the stability of miR-30c and augment its delivery to liver cells. Here, we report the successful synthesis of a series of miR-30c analogs by using different chemically modified nucleosides. In these analogs, we left the active sense strand untouched so that its biological activity remained unaltered, and we modified the passenger strand of miR-30c to enhance the stability and uptake of miR-30c by hepatoma cells through phosphorothiorate linkages and the addition of GalNAc. We show that these analogs significantly reduced apolipoprotein B secretion in Huh-7 human hepatoma cells and human primary hepatocytes without affecting apolipoprotein A1 secretion and cellular lipid levels. Our results provide a proof of concept that the passenger strand of miR-30c can be modified to increase its stability and delivery to cells while retaining the potency of the sense strand. We anticipate these miR-30c analogs will be useful in the development of more efficacious analogs for the treatment of hyperlipidemias and cardiovascular diseases.

miR-30c-5p inhibits glioma proliferation and invasion via targeting Bcl2

Background

Glioma is a highly malignant brain tumor, characterized by the poor prognosis and high recurrence rates. Previous studies have confirmed that miRNA-30c-5p is closely associated with tumor cell biological properties. The present study explored the biological role of miR-30c-5p in human glioma malignant behavior and underlying mechanisms.

Methods

Levels of miR-30c-5p were detected in glioma tissues and adjacent normal tissues. Two glioma cell lines including U87 and U251 were transfected with miR-30c-5p mimic or inhibitors. Cell proliferation was evaluated by MTT assay and colony formation assay. Cell apoptosis and invasive potential of glioma cells were assessed by flow cytometry and transwell assays, respectively. Luciferase reporter assay was performed to validate the target gene of miR-30c-5p.

Results

Levels of miR-30c-5p were dramatically decreased in glioma tissues as compared to the adjacent normal tissues. Upregulation of miR-30c-5p significantly suppressed cell growth and colony formation, and induced apoptosis in glioma cells. In contrast, inhibition of miR-30c-5p promoted the proliferation and inhibited apoptosis in tumor cells. Furthermore, miR-30c-5p strongly suppresses the invasion of glioma cells. Western blot showed that Bcl-2 was significantly decreased following treatment with miR-30c-5p mimics and increased after miR-30c-5p inhibitor treatment. Moreover, luciferase reporter assays indicated that transfection of miR-30c-5p led to a marked reduction of luciferase activity, but had no effect on Bcl-2 3'-UTR mutated fragment. Mechanically, miR-30c-5p promoted the activation of caspase 3 and caspase 9 in glioma cells. Furthermore, miR-30c-5p promoted apoptosis and inhibited colony formation and migration, and knockdown of Bcl2 further increased the number of apoptotic cells and suppressed colony formation and migration of glioma cells. By contrast, miR-30c-5p inhibitors decreased apoptosis and increased colony formation and migration, and restored Bcl2 expression further suppressed glioma cell apoptosis and enhanced colony formation and migration.

Conclusions

These results demonstrated that miR-30c-5p regulated growth, apoptosis and migration in glioma cells by targeting Bcl2, suggesting that miR-30c-5p might serve as a novel target for glioma therapy.

Identification of Circular RNA Expression Profiles in White Adipocytes and Their Roles in Adipogenesis

Obesity and its related metabolic diseases have become great public health threats worldwide. Although accumulated evidence suggests that circRNA is a new type of non-coding RNAs regulating various physiological and pathological processes, little attention has been paid to the expression profiles and functions of circRNAs in white adipose tissue. In this study, 3,771 circRNAs were detected in three stages of white adipogenesis (preadipocyte, differentiating preadipocyte, and mature adipocyte) by RNA-seq. Experimental validation suggested that the RNA-seq results are highly reliable. We found that nearly 10% of genes which expressed linear RNAs in adipocytes could also generate circRNAs. In addition, 40% of them produced multiple circRNA isoforms. We performed correlation analysis and found that a great deal of circRNAs (nearly 50%) and their parental genes were highly correlated in expression levels. A total of 41 differential expression circRNAs (DECs) were detected during adipogenesis and an extremely high ratio of them (80%) were correlated with their parental genes, indicating these circRNAs may potentially play roles in regulating the expression of their parental genes. KEGG enrichment and GO annotation of the parental genes suggesting that the DECs may participate in several adipogenesis-related pathways. Following rigorous selection, we found that many up-regulated circRNAs contain multiple miRNAs binding sites, such as miR17, miR-30c, and miR-130, indicating they may potentially facilitate their regulatory functions by acting as miRNA sponges. These results suggest that plenty of circRNAs are expressed in white adipogenesis and the DECs may serve as new candidates for future adipogenesis regulation.

Macrophage activation in the lung during the progression of nitrogen mustard induced injury is associated with histone modifications and altered miRNA expression

Activated macrophages have been implicated in lung injury and fibrosis induced by the cytotoxic alkylating agent, nitrogen mustard (NM). Herein, we determined if macrophage activation is associated with histone modifications and altered miRNA expression. Treatment of rats with NM (0.125 mg/kg, i.t.) resulted in increases in phosphorylation of H2A.X in lung macrophages at 1 d and 3 d post-exposure. This DNA damage response was accompanied by methylation of histone (H) 3 lysine (K) 4 and acetylation of H3K9, marks of transcriptional activation, and methylation of H3K36 and H3K9, marks associated with transcriptional repression. Increases in histone acetyl transferase and histone deacetylase were also observed in macrophages 1 d and 28 d post-NM exposure. PCR array analysis of miRNAs (miR)s involved in inflammation and fibrosis revealed unique and overlapping expression profiles in macrophages isolated 1, 3, 7, and 28 d post-NM. An IPA Core Analysis of predicted mRNA targets of differentially expressed miRNAs identified significant enrichment of Diseases and Functions related to cell cycle arrest, apoptosis, cell movement, cell adhesion, lipid metabolism, and inflammation 1 d and 28 d post NM. miRNA-mRNA interaction network analysis revealed highly connected miRNAs representing key upstream regulators of mRNAs involved in significantly enriched pathways including miR-34c-5p and miR-27a-3p at 1 d post NM and miR-125b-5p, miR-16-5p, miR-30c-5p, miR-19b-3p and miR-148b-3p at 28 d post NM. Collectively, these data show that NM promotes histone remodeling and alterations in miRNA expression linked to lung macrophage responses during inflammatory injury and fibrosis.

A small nucleolar RNA, SNORD126, promotes adipogenesis in cells and rats by activating the PI3K-AKT pathway

Small nucleolar RNA (snoRNA) plays important role in various histogenesis. Whether snoRNA plays a role in adipogenesis is unknown. SNORD126 is a C/D box snoRNA. We previously demonstrated that SNORD126 promoted hepatocellular carcinoma cell growth by activating the phosphoinositide 3-kinase-protein kinase B (Akt) pathway through upregulating fibroblast growth factor receptor 2 expression. In the present study, we found that the expression of SNORD126 was downregulated in the obesity-related tissues in high-fat diet-fed rats. Overexpression of SNORD126 in 3T3-L1 cells promoted adipocytes differentiation. SNORD126 significantly increased the expression of CCAAT/enhancer-binding protein α, fatty acid-binding protein 4, peroxisome proliferative-activated receptor-γ, and the phosphorylation of Akt and p70S6K. Overexpression of SNORD126 in human adipose-derived stem cells stimulated adipogenesis and increased phosphorylation of Akt. Meanwhile, SNORD126 increased the messenger RNA and protein levels of cyclin D1 and cyclin-dependent kinase 2, which promoted mitotic clonal expansion progression during the early stage of 3T3-L1 cell differentiation. We further found that SNORD126 accelerated the growth of the groin fat pad and increased phosphorylation of Akt and p70S6K in rats. Overall, our results suggested that SNORD126 promoted adipocyte differentiation through increasing phosphorylation of Akt and p70S6K both in vitro and in vivo.

MiR-30c-5p Directly Targets MAPK1 to Regulate the Proliferation, Migration and Invasion of Adenomyotic Epithelial Cells in Adenomyosis

The purpose of our study was to elucidate the functions of miR-30c-5p on adenomyosis for exploring novel treatment strategies. We first detected the expression of miR-30c-5p in clinical adenomyotic tissues and isolated endometrial cells from adenomyotic tissues. Next, gain and loss-of-function assays were performed to detect the effect of miR-30c-5p on adenomyotic endometrial cells. Further, luciferase assay and real-time polymerase chain reaction as well as western blot were conducted to investigate the potential target of miR-30c-5p; and transwell assay, wound-healing assay and CCK-8 assay were used to evaluate the effects of miR-30c-5p and its target on regulating biological functions of adenomyotic endometrial cells. Our results found that miR-30c-5p was down-regulated in both adenomyosis tissues and adenomyotic epithelial cells, which correlated with dysmenorrhea, longer duration of symptoms and more menstrual bleeding. Moreover, the overexpression of miR-30c-5p inhibited the proliferation, migration and invasion of adenomyotic epithelial cells, where miR-30c-5p knockdown had an opposite effect. Furthermore, we confirmed mitogen-activated protein kinase 1 (MAPK1) was one of the direct targets of miR-30c-5p, indicating its important role in miR-30c-5p-mediated suppression of proliferation, invasion and migration in adenomyotic epithelial cells. This study showed that the interaction of miR-30c-5p with MAPK1 can regulate the proliferation, invasion and migration in adenomyotic epithelial cells.

Hypoxia-induced miR-27 and miR-195 regulate ATP consumption, viability, and metabolism of rat cardiomyocytes by targeting PPARγ and FASN expression

This study examined whether hypoxia-induced microRNA (miRNA) upregulation was related to the inhibition of chondriosome aliphatic acid oxidation in myocardial cells under anoxia. We showed that anoxia induced high expression of hypoxia-inducible factor-1-alpha, muscle carnitine palmitoyltransferase I, and vascular endothelial growth factor in cardiomyocytes. Meanwhile, miR-27 and miR-195 were also upregulated in hypoxia-induced cardiomyocytes. Furthermore, hypoxia induction led to reductions in the adenosine triphosphate (ATP) consumption rate and oxidative metabolism as well as an increase in cardiomyocyte glycolysis. Metabolic reprogramming was reduced by hypoxia, as evidenced by the downregulation of sirtuin 1, forkhead box protein O1, sterol regulatory element-binding protein 1c, ATP citrate lyase, acetyl-coenzyme A carboxylase 2, adiponutrin, adipose triglyceride lipase, and glucose transporter type 4, while miR-27 and miR-195 inhibition partially recovered the expression of these transcription factors. In addition, hypoxia induction reduced cell viability and survival by triggering apoptosis; however, miR-27 and miR-195 inhibition partially increased cell viability. Moreover, miR-27 and miR-195 targeted the 3’untranslated regions of two key lipid-associated metabolic players, peroxisome proliferator-activated receptor gamma and fatty acid synthase. In conclusion, miR-27 and miR-195 are related to hypoxia-mediated ATP levels, glycolysis, oxidation, cell survival, and a cascade of transcription factors that control metabolism in cardiomyocytes.

MiR-25-3p regulates the differentiation of intramuscular preadipocytes in goat via targeting KLF4

Adipocyte differentiation, which plays an important role in fat deposition, involves a complex molecular mechanism. MicroRNAs (miRNAs) are essential in this progress. Here, we showed that miR-25-3p expression had increased during goat intramuscular preadipocyte differentiation, which peaked at day 3. Using liposome transfection and qRT-PCR techniques, we found that knocking down miR-25-3p reduced the accumulation of lipid droplets by downregulating or upregulating the expression of LPL, PPARγ, AP2, SREBP1, and C/EBPβ but upregulating the expression of KLF4. Overexpression of miR-25-3p results in the opposite. Furthermore, the dual luciferase assay showed that overexpression of miR-25-3p significantly inhibited luciferase activity of KLF4. These results showed that miR-25-3p has a binding site within the 3′-UTR of KLF4 mRNA. Together, these findings indicate that miR-25-3p is a positive regulator of intramuscular preadipocyte differentiation via targeting to KLF4 in goats.

Downregulation of miR-30c-5p expression in colorectal cancer tissue is sex-dependent

We report that decreased expression of miR-30c in tumor compared to adjacent tissue is sex-dependent in colorectal cancer (CRC) patients. High expression of miR-30c was associated with better survival in the whole cohort. When the cohort was split into male and female subcohorts, decreased miR-30c expression in tumor compared to adjacent tissue was observed only in males. Expression of miR-30c was decreased in CRC tumor tissue in male patients with nodes involvement compared to those without metastases in nodes and this difference was not observe in females. Next dependency of miR-30c expression on oestrogen receptor beta (ERbeta) mRNA levels in tumor was tested. In males with low expression of ERbeta, we observed a significant decrease in miR-30c levels in patients with nodes involvement compared to those without nodes involvement. This difference was not observed in males with high ERbeta mRNA levels and in females. Accordingly, males with low expression of ERbeta and high expression of miR-30c showed a better survival that those with low expression ERbeta and low expression of miR-30c. It is possible to conclude that whole cohort survival dependence on miR-30c is mostly generated by a subcohort of males with low expression of ERbeta mRNA in tumor tissue.

Evaluation of circulating miR-122, miR-30c and miR-33a levels and their association with lipids, lipoproteins in postprandial lipemia

AIMS

Postprandial lipemia is characterized by an increase in triglyceride-rich lipoproteins after fatty meals. MicroRNAs (miRs) play important roles in lipid and lipoprotein metabolism. The aim of this study was to determine relationship between levels of plasma miR expression and lipoprotein metabolism-related proteins in subjects with normal (NPR) and high postprandial response (HPR) in postprandial period.

MATERIALS AND METHODS

The oral fat tolerance test was applied to 22 individuals with NPR and 22 with HPR.

KEY FINDINGS

Increased expressions of miR-122 and miR-33a and miR-122/30c ratio and decreased miR-30c expression were observed in fasting and postprandial period of HPR compared with NPR. ROC curve analysis showed that miR-122/30c ratio is a good biomarker for postprandial lipemia (AUC: 0.97, p < 0.001). Levels of TG, MTTP, and Apo B-48 and chylomicron (CM) particle size were significantly higher in HPR than in NPR (p < 0.05). The miR-122/30c ratio at 2 h was positively correlated with CM particle size, and with TG, MTTP and Apo B-48 levels at 4th hour. miR-33a expression decreased in HPR and was negatively correlated with ABCA1 and Apo A-1 levels at 4th hour of the postprandial period in both groups.

SIGNIFICANCE

Increased miR-122 and decreased miR-30c expression levels in HPR may play critical roles in elevated or prolonged postprandial lipemia. The miR122/30c ratio exhibited good association with MTTP, Apo B-48 and TG levels, and with CM particle size, and may be a reliable marker for evaluating postprandial lipemia. miR-33a may also play a key role in decreased HDL-C in postprandial lipemia.

Fumonisin B1 Epigenetically Regulates PTEN Expression and Modulates DNA Damage Checkpoint Regulation in HepG2 Liver Cells

Fumonisin B₁ (FB₁), a Fusarium-produced mycotoxin, is found in various foods and feeds. It is a well-known liver carcinogen in experimental animals; however, its role in genotoxicity is controversial. The current study investigated FB₁-triggered changes in the epigenetic regulation of PTEN and determined its effect on DNA damage checkpoint regulation in human liver hepatoma G2 (HepG2) cells. Following treatment with FB₁ (IC₅₀: 200 µM; 24 h), the expression of miR-30c, KDM5B, PTEN, H3K4me3, PI3K, AKT, p-ser473-AKT, CHK1, and p-ser280-CHK1 was measured using qPCR and/or Western blot. H3K4me3 enrichment at the PTEN promoter region was assayed via a ChIP assay and DNA damage was determined using an ELISA. FB₁ induced oxidative DNA damage. Total KDM5B expression was reduced, which subsequently increased the total H3K4me3 and the enrichment of H3K4me3 at PTEN promoters. Increased H3K4me3 induced an increase in PTEN transcript levels. However, miR-30c inhibited PTEN translation. Thus, PI3K/AKT signaling was activated, inhibiting CHK1 activity via phosphorylation of its serine 280 residue preventing the repair of damaged DNA. In conclusion, FB₁ epigenetically modulates the PTEN/PI3K/AKT signaling cascade, preventing DNA damage checkpoint regulation, and induces significant DNA damage.

Differentially Expressed miRNA-Gene Targets Related to Intramuscular Fat in Musculus Longissimus Dorsi of Charolais × Holstein F2-Crossbred Bulls

Intramuscular fat (IMF) is a meat quality indicator associated with taste and juiciness. IMF deposition, influenced by genetic and non-genetic factors, occurs through a transcriptionally coordinated process of adipogenesis. MicroRNAs (miRNAs) are transcriptional regulators of vital biological processes, including lipid metabolism and adipogenesis. However, in bovines, limited data on miRNA profiling and association with divergent intramuscular fat content, regulated exclusively by genetic parameters, have been reported. Here, a microarray experiment was performed to identify and characterize the miRNA expression pattern in the Musculus longissimus dorsi of F₂-cross (Charolais × German Holstein) bulls with high and low IMF. A total of 38 differentially expressed miRNAs (DE miRNAs), including 33 upregulated and 5 downregulated (corrected p-value ≤ 0.05, FC ≥ ±1.2), were reported. Among DE miRNAs, the upregulated miRNAs miR-105a/b, miR-695, miR-1193, miR-1284, miR-1287-5p, miR-3128, miR-3178, miR-3910, miR-4443, miR-4445 and miR-4745, and the downregulated miRNAs miR-877-5p, miR-4487 and miR-4706 were identified as novel fat deposition regulators. DE miRNAs were further analyzed, along with previously identified differentially expressed genes (DEGs) from the same samples and predicted target genes, using multiple bioinformatic approaches, including target prediction tools and co-expression networks, as well as Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. We identified DE miRNAs and their gene targets associated with bovine intramuscular adipogenesis, and we provide a basis for further functional investigations.

Compounds that modulate AMPK activity and hepatic steatosis impact the biosynthesis of microRNAs required to maintain lipid homeostasis in hepatocytes

Background

While the impact of metformin in hepatocytes leads to fatty acid (FA) oxidation and decreased lipogenesis, hepatic microRNAs (miRNAs) have been associated with fat overload and impaired metabolism, contributing to the pathogenesis of non-alcoholic fatty liver disease (NAFLD).

Methods

We investigated the expression of hundreds of miRNAs in primary hepatocytes challenged by compounds modulating steatosis, palmitic acid and compound C (as inducers), and metformin (as an inhibitor). Then, additional hepatocyte and rodent models were evaluated, together with transient mimic miRNAs transfection, lipid droplet staining, thin-layer chromatography, quantitative lipidomes, and mitochondrial activity, while human samples outlined the translational significance of this work.

Findings

Our results show that treatments triggering fat accumulation and AMPK disruption may compromise the biosynthesis of hepatic miRNAs, while the knockdown of the miRNA-processing enzyme DICER in human hepatocytes exhibited increased lipid deposition. In this context, the ectopic recovery of miR-30b and miR-30c led to significant changes in genes related to FA metabolism, consistent reduction of ceramides, higher mitochondrial activity, and enabled β-oxidation, redirecting FA metabolism from energy storage to expenditure.

Interpretation

Current findings unravel the biosynthesis of hepatic miR-30b and miR-30c in tackling inadequate FA accumulation, offering a potential avenue for the treatment of NAFLD.

Funding

Instituto de Salud Carlos III (ISCIII), Govern de la Generalitat (PERIS2016), Associació Catalana de Diabetis (ACD), Sociedad Española de Diabetes (SED), Fondo Europeo de Desarrollo Regional (FEDER), Xunta de Galicia, Ministerio de Economía y Competitividad (MINECO), “La Caixa” Foundation, and CIBER de la Fisiopatología de la Obesidad y Nutrición (CIBEROBN).

lncRNA DLEU2 modulates cell proliferation and invasion of non-small cell lung cancer by regulating miR-30c-5p/SOX9 axis

Increasing evidence indicated that long noncoding RNAs (lncRNA) play critical roles in the progression of multiple cancers and that dysregulation of lncRNA promotes tumor progression. However, the function and underlying mechanism of lncRNA DLEU2 in biological behaviors of NSCLC cells are still largely unknown. Our studies confirmed that lncRNA DLEU2 was highly expressed in NSCLC tissues and cell lines, which was correlated with shorter overall survival in NSCLC patients. In vitro, knockdown of lncRNA DLEU2 inhibited proliferation, invasion, migration and induced apoptosis of both A549 and LLC cells; In vivo, it suppressed tumor growth and metastasis. lncRNA DLEU2 directly interacted with miR-30c-5p, which further targeted SOX9 and exerted oncogenic functions in NSCLC. Mechanistically, overexpression of lncRNA DLEU2 exhibits tumorigenic effects through downregulating the inhibitory effect of miR-30c-5p on SOX9 expression. In conclusion, Our finding confirmed that lncRNA DLEU2 as a novel oncogenic in NSCLC, which provide a potential novel diagnostic and therapeutic target for NSCLC.

Hypoxia decreases macrophage glycolysis and M1 percentage by targeting microRNA-30c and mTOR in human gastric cancer

Macrophages are essential inflammatory cells which regulate the features of immune reactions within tumors. Many studies have reported their regulatory roles in immunity through cytokines and cell signaling. However, relatively few studies have focused on their metabolic features and mechanisms. We aimed to determine the signaling pathway regulating cell metabolism and the mechanism related to the regulation of human tumor-associated macrophages (TAMs) in gastric cancer (GC). Tumor-infiltrated macrophages were isolated from human GC tissues using magnetic beads, gene transcription was determined by real-time PCR, protein expression was monitored using western blots, metabolites were determined using HPLC, and transcriptional regulation was analyzed by the luciferase-based reporter gene system. A significant decrease in microRNA (miR)-30c and an increase in regulated in development and DNA damage responses 1 (REDD1) were detected in human GC TAMs, the transcription of miR-30c was negatively correlated with REDD1. MicroRNA-30c expression was suppressed by hypoxia-inducible factor-1α activation and related to decreased mTOR activity as well as glycolysis in human GC TAMs. Hypoxia-regulated miR-30c downregulated REDD-1 expression by targeting its 3'UTR. Overexpression of miR-30c or restored mTOR activity in macrophages with miR-30cLow expression promoted M1 macrophage differentiation and function in TAMs. Therefore, hypoxia in the human GC microenvironment suppressed the expression of miR-30c, and decreased mTOR activity as well as glycolysis in GC TAMs, thus inhibiting M1 differentiation and function. These results provide a novel metabolic strategy for tumor microenvironment-based therapy.

Dedifferentiation of Primary Hepatocytes is Accompanied with Reorganization of Lipid Metabolism Indicated by Altered Molecular Lipid and miRNA Profiles

Aim: Primary human hepatocytes (PHHs) undergo dedifferentiation upon the two-dimensional (2D) culture, which particularly hinders their utility in long-term in vitro studies. Lipids, as a major class of biomolecules, play crucial roles in cellular energy storage, structure, and signaling. Here, for the first time, we mapped the alterations in the lipid profile of the dedifferentiating PHHs and studied the possible role of lipids in the loss of the phenotype of PHHs. Simultaneously, differentially expressed miRNAs associated with changes in the lipids and fatty acids (FAs) of the dedifferentiating PHHs were investigated. Methods: PHHs were cultured in monolayer and their phenotype was monitored morphologically, genetically, and biochemically for five days. The lipid and miRNA profile of the PHHs were analyzed by mass spectrometry and Agilent microarray, respectively. In addition, 24 key genes involved in the metabolism of lipids and FAs were investigated by qPCR. Results: The typical morphology of PHHs was lost from day 3 onward. Additionally, ALB and CYP genes were downregulated in the cultured PHHs. Lipidomics revealed a clear increase in the saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) containing lipids, but a decrease in the polyunsaturated fatty acids (PUFA) containing lipids during the dedifferentiation of PHHs. In line with this, FASN, SCD, ELOVL1, ELOVL3, and ELOVL7 were upregulated but ELOVL2 was downregulated in the dedifferentiated PHHs. Furthermore, differentially expressed miRNAs were identified, and the constantly upregulated miR-27a and miR-21, and downregulated miR-30 may have regulated the synthesis, accumulation and secretion of PHH lipids during the dedifferentiation. Conclusion: Our results showed major alterations in the molecular lipid species profiles, lipid-metabolizing enzyme expression as wells as miRNA profiles of the PHHs during their prolonged culture, which in concert could play important roles in the PHHs’ loss of phenotype. These findings promote the understanding from the dedifferentiation process and could help in developing optimal culture conditions, which better meet the needs of the PHHs and support their original phenotype.

Serum miR-30c Level Predicted Cardiotoxicity in Non-small Cell Lung Cancer Patients Treated with Bevacizumab

Cardiotoxicity is a common adverse effect induced by drug chemotherapy. miR-30c has been reported to be involved in the progress of heart diseases. In the present study, miR-30c was used to predict the cardiotoxicity in non-small cell lung cancer (NSCLC) patients treated with bevacizumab chemotherapy. Eighty NSCLC patients were included in this study. Serum miR-30c levels were detected at pre-chemotherapy, during-chemotherapy (the 2nd, 4th, and 8th week) and 1 month after chemotherapy. miR-30c expression was elevated with the duration of the chemotherapy cycle and decreased 1 month after chemotherapy. The correlation analysis showed that serum miR-30c levels were positively related to cardiotoxicity before chemotherapy and during chemotherapy. ROC curve analysis showed the values of AUC, sensitivity, and specificity for the level of miR-30c alteration (from pre-chemotherapy to during-chemotherapy) were 0.851, 0.720, and 0.860, respectively. Serum miR-30c level is elevated during bevacizumab chemotherapy, which is probably an early detection biomarker for predicting cardiotoxicity in NSCLC patients treated with drug chemotherapy.

Whole transcriptome sequencing reveals biologically significant RNA markers and related regulating biological pathways in cardiomyocyte hypertrophy induced by high glucose

Cardiomyocyte hypertrophy is a physiological adaptation used in an attempt to augment or preserve cardiac function for short periods. Long-term cardiomyocyte hypertrophy often progresses to heart failure. Previous studies have presented comprehensive mechanisms underlying cardiomyocyte hypertrophy, such as signaling pathways, marker genes, and marker miRNAs or lncRNAs. However, the mechanism in RNA level is still unclear. In this study, we used the whole transcriptome technology on cardiomyocety hypertrophy cells, which were cultured with a high concentration of d-glucose. Many differentially expressed markers, including genes, lncRNAs, miRNAs, and circRNAs were identified. Further quantitative real-time PCR verified the highly specific expressed genes, such as Eid1, Timm8b, Mrpl50, Dusp18, Abrc1, Klf13, and Igf1. Moreover, the functional pathways were also enriched with the differentially expressed lncRNA, miRNA, and circRNA. Our study gives new insights into cardiomyocyte hypertrophy and makes great progress in comprehending its mechanism.

MicroRNA-30c-5p inhibits NLRP3 inflammasome-mediated endothelial cell pyroptosis through FOXO3 down-regulation in atherosclerosis

Atherosclerosis is a chronic inflammatory disease involved in endothelial dysfunction. Pyroptosis is a pro-inflammatory form of cell death and plays pivotal roles in atherosclerosis. MicroRNAs (miRNAs) are implicated in atherosclerosis, however the mechanisms that underlie miR-30c-5p is required for endothelial cell pyroptosis remain elusive. In the present study, we probed the interaction of miR-30c-5p with forkhead box O3 (FOXO3) and investigated the effect of miR-30c-5p and FOXO3 on NLRP3 inflammasome and endothelial cell pyroptosis. Introduction of oxidized low density lipoprotein (ox-LDL) dose-dependently increased lactate dehydrogenase (LDH) release as well as pyroptosis in human aortic endothelial cells (HAECs). On the basis of ox-LDL treatment, we found the expression of miR-30c-5p was impaired and enrichment of miR-30c-5p protected HAECs from ox-LDL-induced pyroptosis. Moreover, addition of miR-30c-5p inhibited ox-LDL-activated NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, which was associated with HEACs pyroptosis. Nevertheless, miR-30c-5p failed to show efficacy of Toll-like receptor (TLR) signaling of NLRP3 inflammasome activation. Intriguingly, FOXO3 was suggested to be targeted by miR-30c-5p and addition of miR-30c-5p blocked FOXO3 expression, whereas miR-30c-5p depletion showed opposite effects. Furthermore, silencing of FOXO3 inhibited NLRP3-mediated pyroptosis and reversed anti-miR-30c-5p-induced activation of NLRP3 inflammasome and pyroptosis in HEACs with ox-LDL treatment. Our finding suggested that miR-30c-5p might play essential role in NLRP3 inflammasome-modulated cell pyroptosis by targeting FOXO3 in HAECs, providing a novel therapeutic avenue for atherosclerosis treatment.

Exploring miRNA-mRNA regulatory network in cardiac pathology in Na+/H+ exchanger isoform 1 transgenic mice

Numerous studies have demonstrated that Na⁺/H⁺ exchanger isoform 1 (NHE1) is elevated in myocardial diseases and its effect is detrimental. To better understand the involvement of NHE1, we have previously studied cardiac-specific NHE1 transgenic mice and shown that these mice develop cardiac hypertrophy, interstitial fibrosis, and cardiac dysfunction. The purpose of current study was to identify microRNAs and their mRNA targets involved in NHE1-mediated cardiac injury. An unbiased high-throughput sequencing study was performed on both microRNAs and mRNAs. RNA sequencing showed that differentially expressed genes were enriched in hypertrophic cardiomyopathy pathway by Kyoto Encyclopedia of Genes and Genomes annotation in NHE1 transgenic hearts. These genes were classified as contraction defects (e.g., Myl2, Myh6, Mybpc3, and Actb), impaired intracellular Ca²⁺ homeostasis (e.g., SERCA2a, Ryr2, Rcan1, and CaMKII delta), and signaling molecules for hypertrophic cardiomyopathy (e.g., Itga/b, IGF-1, Tgfb2/3, and Prkaa1/2). microRNA sequencing revealed that 15 microRNAs were differentially expressed (2-fold, P < 0.05). Six of them (miR-1, miR-208a-3p, miR-199a-5p, miR-21-5p, miR-146a-5p, and miR-30c-5p) were reported to be related to cardiac pathological functions. The integrative analysis of microRNA and RNA sequencing data identified several crucial microRNAs including miR-30c-5p, miR-199a-5p, miR-21-5p, and miR-34a-5p as well as 10 of their mRNA targets that may affect the heart via NFAT hypertrophy and cardiac hypertrophy signaling. Furthermore, important microRNAs and mRNA targets were validated by quantitative PCR. Our study comprehensively characterizes the expression patterns of microRNAs and mRNAs, establishes functional microRNA-mRNA pairs, elucidates the potential signaling pathways, and provides novel insights on the mechanisms underlying NHE1-medicated cardiac injury.

miR‑23b inhibits proliferation of SMMC‑7721 cells by directly targeting IL‑11

Hepatocellular carcinoma (HCC) is the third leading cause of cancer‑associated mortality in the 21st century. microRNA (miR)‑23b has been shown to be involved in the pathogenesis of many cancers, including breast and prostate cancer. However, the role of miR‑23b in HCC remains unclear. The present study revealed a negative correlation between miR‑23b expression in HCC tissues and progression of carcinomas. Compared to normal tissues, miR‑23b expression was significantly downregulated in HCC tissues, whereas the expression of interleukin (IL)‑11 and IL‑11 receptor α (IL‑11Rα) was significantly upregulated, indicating that miR‑23b expression is negatively correlated with IL‑11 and IL‑11Rα expression. In addition, miR‑23b inhibited proliferation and promoted apoptosis of SMMC‑7721 cells. This effect was mediated by IL‑11, which was found to be the direct target of miR‑23b in this study. These results indicated that miR‑23b regulates IL‑11 and IL‑11Rα expression, and might act as an anti‑oncogenic agent in the progression of HCC by directly downregulating IL‑11 expression.

Functional miRNA variants affect lung cancer susceptibility and platinum-based chemotherapy response

Background

Platinum-based chemotherapy is widely used as the first-line treatment of lung cancer. MicroRNAs have an important role in lung carcinogenesis and progression. Single-nucleotide polymorphisms (SNPs) in miRNA involved in miRNA biogenesis and structural alteration may affect miRNA expression. In this study, we aimed to investigate the association of functional miRNA variants with the lung cancer susceptibility and platinum-based chemotherapy response.

Methods

Nine genetic polymorphisms in miR-605, 146a, 149, 196a-2, 27a, 499, 30c-1, 5197 and let-7a-2 were selected with comprehensive collection strategy and genotyped by MALDI-TOF mass spectrometry in a total of 215 health control and 507 lung cancer patients (386 patients received at least two consecutive cycles of platinum-based chemotherapy).

Results

We found that an allele carriers of miR-146a rs2910164 (P=0.022, OR=1.315) and C allele carriers of miR-149 rs71428439 (P=0.042, OR=1.372) performance a high risk of lung cancer. Mir-30c-1 rs928508 (P=0.005, in recessive model) and let-7a-2 rs629367 (P=0.030 and P=0.021, in additive and dominant models, respectively) showed strong relationship with lung cancer risk in age under 57 years. The rs11614913 (miR-196a-2) C allele or rs9280508 (miR-30c-1) G allele carriers shown more sensitive to platinum both in additive (P=0.010, P=0.022, respectively) and dominant models (P=0.001, P=0.018, respectively).

Conclusions

These findings suggested that SNPs rs71428439 (miR-149), rs2910164 (miR-146a), rs928508 (mir-30c-1) and rs629367 (let-7a-2) were associated with the lung cancer prevalence, polymorphisms of rs11614913 (miR-196a-2) and rs9280508 (miR-30c-1) significantly influenced the patients' response to platinum-based chemotherapy, which may serve as potential clinical biomarkers to predict lung cancer risk and platinum-based chemotherapy response.

Effect of β-hydroxy-β-methylbutyrate on miRNA expression in differentiating equine satellite cells exposed to hydrogen peroxide

Background

Skeletal muscle injury activates satellite cells to initiate processes of proliferation, differentiation, and hypertrophy in order to regenerate muscle fibers. The number of microRNAs and their target genes are engaged in satellite cell activation. β-Hydroxy-β-methylbutyrate (HMB) is known to prevent exercise-induced muscle damage. The purpose of this study was to evaluate the effect of HMB on miRNA and relevant target gene expression in differentiating equine satellite cells exposed to H₂O₂. We hypothesized that HMB may regulate satellite cell activity, proliferation, and differentiation, hence attenuate the pathological processes induced during an in vitro model of H₂O₂-related injury by changing the expression of miRNAs.

Methods

Equine satellite cells (ESC) were isolated from the samples of skeletal muscle collected from young horses. ESC were treated with HMB (24 h) and then exposed to H₂O₂ (1 h). For the microRNA and gene expression assessment microarrays, technique was used. Identified miRNAs and genes were validated using real-time qPCR. Cell viability, oxidative stress, and cell damage were measured using colorimetric method and flow cytometry.

Results

Analysis of miRNA and gene profile in differentiating ESC pre-incubated with HMB and then exposed to H₂O₂ revealed difference in the expression of 27 miRNAs and 4740 genes, of which 344 were potential target genes for identified miRNAs. Special attention was focused on differentially expressed miRNAs and their target genes involved in processes related to skeletal muscle injury. Western blot analysis showed protein protection in HMB-pre-treated group compared to control. The viability test confirmed that HMB enhanced cell survival after the hydrogen peroxide exposition.

Conclusions

Our results suggest that ESC pre-incubated with HMB and exposed to H₂O₂ could affect expression on miRNA levels responsible for skeletal muscle development, cell proliferation and differentiation, and activation of tissue repair after injury. Enrichment analyses for targeted genes revealed that a large group of genes was associated with the regulation of signaling pathways crucial for muscle tissue development, protein metabolism, muscle injury, and regeneration, as well as with oxidative stress response.

Retracted Article: Long non-coding RNA XIST promotes proliferation, autophagy and inhibits apoptosis by regulating microRNA-30c/ATG5 axis in gastric cancer

Background: Gastric cancer (GC) is a great threat to human health and life. Long non-coding RNA X inactive-specific transcript (XIST) and microRNA-30c (miR-30c) function as crucial players in the tumorigenesis of GC. Bioinformatics analysis suggests that miR-30c has a chance to interact with XIST and autophagy related 5 (ATG5). Moreover, ATG5 has been identified as a target of miR-30c in human intestinal epithelial cells. Hence, whether XIST could regulate cell proliferation, apoptosis and autophagy by miR-30c/ATG5 axis was further investigated in GC. Methods: The levels of XIST, miR-30c and ATG5 mRNA were measured by RT-qPCR assay. ATG5, p62, LC3-I, and LC3-II protein expression was detected by western blot assay. The relationships of XIST, miR-30c and ATG5 were examined by luciferase, RNA immunoprecipitation (RIP) and RNA pull down assays. Cell proliferation was assessed by MTS assay. Cell apoptotic rate was determined using flow cytometry. ATG5 protein expression in tissues was measured by immunohistochemistry (IHC) assay. Results: XIST was highly expressed in GC tissues and cell lines. XIST knockdown suppressed proliferation, autophagy and promoted apoptosis in GC cells. XIST inhibited miR-30c expression by direct interaction in GC cells. Furthermore, miR-30c depletion abrogated XIST deficiency-mediated anti-proliferation, pro-apoptosis and anti-autophagy effects in GC cells. Additionally, ATG5 was a target of miR-30c and XIST promoted ATG5 expression by sequestering miR-30c from ATG5 in GC cells. Conclusion: XIST knockdown suppressed proliferation, autophagy and induced apoptosis through regulating miR-30c/ATG5 axis in GC cells, hinting at the potential value of XIST in the management of GC.

Gastric cancer (GC) is a great threat to human health and life.

Systems genetics identifies a co-regulated module of liver microRNAs associated with plasma LDL cholesterol in murine diet-induced dyslipidemia

Chronically altered levels of circulating lipids, termed dyslipidemia, is a significant risk factor for a number of metabolic and cardiovascular morbidities. MicroRNAs (miRNAs) have emerged as important regulators of lipid balance, have been implicated in dyslipidemia, and have been proposed as candidate therapeutic targets in lipid-related disorders including atherosclerosis. A major limitation of most murine studies of miRNAs in lipid metabolic disorders is that they have been performed in just one (or very few) inbred strains, such as C57BL/6. Moreover, although individual miRNAs have been associated with lipid phenotypes, it is well understood that miRNAs likely work together in functional modules. To address these limitations, we implemented a systems genetics strategy using the Diversity Outbred (DO) mouse population. Specifically, we performed gene and miRNA expression profiling in the livers from ~300 genetically distinct DO mice after 18 wk on either a high-fat/high-cholesterol diet or a high-protein diet. Large-scale correlative analysis of these data with a wide range of cardio-metabolic end points revealed a co-regulated module of miRNAs significantly associated with circulating low-density lipoprotein cholesterol (LDL-C) levels. The hubs of this module were identified as miR-199a, miR-181b, miR-27a, miR-21_-_1, and miR-24. In sum, we demonstrate that a high-fat/high-cholesterol diet robustly rewires the miRNA regulatory network, and we identify a small group of co-regulated miRNAs that may exert coordinated effects to control circulating LDL-C.

Global mapping of miRNA-target interactions in cattle (Bos taurus)

With roles in development, cell proliferation and disease, micro-RNA (miRNA) biology is of great importance and a potential therapeutic target. Here we used cross-linking immunoprecipitation (CLIP) and ligation of miRNA-target chimeras on the Argonaute (AGO) protein to globally map miRNA interactions in the cow. The interactome is the deepest reported to date. miRNA targeting principles are consistent with observations in other species, but with expanded pairing rules. Experimental mapping robustly predicted functional miR-17 regulatory sites. From miRNA-specific targeting for >5000 mRNAs we determined gene ontologies (GO). This confirmed repression of genes important for embryonic development and cell cycle progress by the let-7 family, and repression of those involved in cell cycle arrest by the miR-17 family, but also suggested a number of unappreciated miRNA functions. Our results provide a significant resource for understanding of bovine and species-conserved miRNA regulation, and demonstrate the power of experimental methods for establishing comprehensive interaction maps.

Human MicroRNA-548p Decreases Hepatic Apolipoprotein B Secretion and Lipid Synthesis

OBJECTIVE

MicroRNAs (miRs) play important regulatory roles in lipid metabolism. Apolipoprotein B (ApoB), as the only essential scaffolding protein in the assembly of very-low-density lipoproteins, is a target to treat hyperlipidemia and atherosclerosis. We aimed to find out miRs that reduce apoB expression.

APPROACH AND RESULTS

Bioinformatic analyses predicted that hsa-miR-548p can interact with apoB mRNA. MiR-548p or control miR was transfected in human and mouse liver cells to test its role in regulating apoB secretion and mRNA expression levels. Site-directed mutagenesis was used to identify the interacting site of miR-548p in human apoB 3'-untranslated region. Fatty acid oxidation and lipid syntheses were examined in miR-548p overexpressing cells to investigate its function in lipid metabolism. We observed that miR-548p significantly reduces apoB secretion from human hepatoma cells and primary hepatocytes. Mechanistic studies showed that miR-548p interacts with the 3'-untranslated region of human apoB mRNA to enhance post-transcriptional degradation. Bioinformatic algorithms suggested 2 potential binding sites of miR-548p on human apoB mRNA. Site-directed mutagenesis studies revealed that miR-548p targets site I involving both seed and supplementary sequences. MiR-548p had no effect on fatty acid oxidation but significantly decreased lipid synthesis in human hepatoma cells by reducing HMGCR (3-hydroxy-3-methylglutaryl-coenzyme A reductase) and ACSL4 (Acyl-CoA synthetase long-chain family member 4) enzymes involved in cholesterol and fatty acid synthesis. In summary, miR-548p reduces lipoprotein production and lipid synthesis by reducing expression of different genes in human liver cells.

CONCLUSIONS

These studies suggest that miR-548p regulates apoB secretion by targeting mRNA. It is likely that it could be useful in treating atherosclerosis, hyperlipidemia, and hepatosteatosis.

MicroRNA-30c Mimic Mitigates Hypercholesterolemia and Atherosclerosis in Mice

High plasma cholesterol levels are a major risk factor for atherosclerosis. Plasma cholesterol can be reduced by inhibiting lipoprotein production; however, this is associated with steatosis. Previously we showed that lentivirally mediated hepatic expression of microRNA-30c (miR-30c) reduced hyperlipidemia and atherosclerosis in mice without causing hepatosteatosis. Because viral therapy would be formidable, we examined whether a miR-30c mimic can be used to mitigate hyperlipidemia and atherosclerosis without inducing steatosis. Delivery of a miR-30c mimic to the liver diminished diet-induced hypercholesterolemia in C57BL/6J mice. Reductions in plasma cholesterol levels were significantly correlated with increases in hepatic miR-30c levels. Long term dose escalation studies showed that miR-30c mimic caused sustained reductions in plasma cholesterol with no obvious side effects. Furthermore, miR-30c mimic significantly reduced hypercholesterolemia and atherosclerosis in Apoe(-/-) mice. Mechanistic studies showed that miR-30c mimic had no effect on LDL clearance but reduced lipoprotein production by down-regulating microsomal triglyceride transfer protein expression. MiR-30c had no effect on fatty acid oxidation but reduced lipid synthesis. Additionally, whole transcriptome analysis revealed that miR-30c mimic significantly down-regulated hepatic lipid synthesis pathways. Therefore, miR-30c lowers plasma cholesterol and mitigates atherosclerosis by reducing microsomal triglyceride transfer protein expression and lipoprotein production and avoids steatosis by diminishing lipid syntheses. It mitigates atherosclerosis most likely by reducing lipoprotein production and plasma cholesterol. These findings establish that increasing hepatic miR-30c levels is a viable treatment option for reducing hypercholesterolemia and atherosclerosis.

MicroRNA-30c promotes natural killer cell cytotoxicity via up-regulating the expression level of NKG2D

AIMS

Natural killer (NK) cells play critical roles in antitumor immunity. Our previous study showed that over-expression of miR-30c-1* enhanced NKL cell cytotoxicity through up-regulation of tumor necrosis factor-α via directly targeting transcription factor homeobox containing 1. MiR-30c, the complimentary microRNA of miR-30c-1*, has been found to exert regulatory effect on T cell function. However, the effect of miR-30c on NK cells is unknown. Therefore, this study aimed to investigate whether miR-30c could play a role to enhance NK cell activation and cytotoxicity.

MAIN METHODS

Chemosynthesis exogenous miR-30c mimics and miR-30c inhibitor were transfected into NKL cells and isolated human peripheral blood NK cells, respectively. The expression levels of NK group 2, member D (NKG2D), CD107a and FasL on cell surface and cytotoxic ability of miRNAs transfected NKL cells against SMMC-7721 cells were evaluated.

KEY FINDINGS

MiR-30c could increase the expression of NKG2D and CD107a on NKL cells, and enhance cytotoxic ability of NKL cells to kill SMMC-7721 cells. Moreover, miR-30c could up-regulate the expression of FasL on both NKL cells and human peripheral blood NK cells. However, the peripheral blood NK cells from only four in ten healthy donors appeared high expression levels of NKG2D and CD107a after miR-30c transfection.

SIGNIFICANCE

MiR-30c could promote the cytotoxicity of NKL cells in vitro by up-regulating the expression levels of NKG2D, CD107a and FasL. However, the effect of miR-30c on ex vivo NK cells from different human individuals is diverse, indicating that miR-30c may play complicate and fine adjustment in immune system.

MicroRNAs regulating apolipoprotein B-containing lipoprotein production

MicroRNAs (miRs) are small, non-coding RNAs that regulate gene expression and have been implicated in many pathological conditions. Significant progress has been made to unveil their role in lipid metabolism. This review aims at summarizing the role of different miRs that regulate hepatic assembly and secretion of apolipoprotein B (apoB)-containing lipoproteins. Overproduction and/or impaired clearance of these lipoproteins from circulation increase plasma concentrations of lipids enhancing risk for cardiovascular disease. So far, three miRs, miR-122, miR-34a, and miR-30c have been shown to modulate hepatic production of apoB-containing low density lipoproteins. In this review, we will first provide a brief overview of lipid metabolism and apoB-containing lipoprotein assembly to orient readers to different steps that have been shown to be regulated by miRs. Then, we will discuss the role of each miR on plasma lipids and atherosclerotic burden. Furthermore, we will summarize mechanistic studies explaining how these miRs regulate hepatic lipid synthesis, fatty acid oxidation, and lipoprotein secretion. Finally, we will briefly highlight the potential use of each miR as a therapeutic drug for treating cardiovascular diseases. This article is part of a Special Issue entitled: MicroRNAs and lipid/energy metabolism and related diseases edited by Carlos Fernández-Hernando and Yajaira Suárez.

Mechanistic Role of MicroRNAs in Coupling Lipid Metabolism and Atherosclerosis

MicroRNAs (miRNAs, miRs) represent a group of powerful and versatile posttranscriptional regulators of gene expression being involved in the fine control of a plethora of physiological and pathological processes. Besides their well-established crucial roles in the regulation of cell cycle, embryogenesis or tumorigenesis, these tiny molecules have also been shown to participate in the regulation of lipid metabolism. In particular, miRs orchestrate cholesterol and fatty acids synthesis, transport, and degradation and low-density and high-density lipoprotein (LDL and HDL) formation. It is thus not surprising that they have also been reported to affect the development and progression of several lipid metabolism-related disorders including liver steatosis and atherosclerosis. Mounting evidence suggests that miRs might represent important "posttranscriptional hubs" of lipid metabolism, which means that one miR usually targets 3'-untranslated regions of various mRNAs that are involved in different steps of one precise metabolic/signaling pathway, e.g., one miR targets mRNAs of enzymes important for cholesterol synthesis, degradation, and transport. Therefore, changes in the levels of one key miR affect various steps of one pathway, which is thereby promoted or inhibited. This makes miRs potent future diagnostic and even therapeutic tools for personalized medicine. Within this chapter, the most prominent microRNAs involved in lipid metabolism, e.g., miR-27a/b, miR-33/33*, miR-122, miR-144, or miR-223, and their intracellular and extracellular functions will be extensively discussed, in particular focusing on their mechanistic role in the pathophysiology of atherosclerosis. Special emphasis will be given on miR-122, the first microRNA currently in clinical trials for the treatment of hepatitis C and on miR-223, the most abundant miR in lipoprotein particles.