Selective TRAIL‐induced cytotoxicity to lung cancer cells mediated by miRNA response elements

Lung cancer is among the most common cancers, and the current therapeutic strategies are still inefficient in most cases. Tumour necrosis factor‐related apoptosis‐inducing ligand (TRAIL) is a promising biological agent for cancer treatment because of its potent pro‐apoptotic effect on cancer cells. However, TRAIL also induces apoptosis in normal cells and therefore may cause toxicity to normal tissues if clinically applied. To address this issue, we inserted microRNA response elements (MREs) of miR‐133a, miR‐137 and miR‐449a, which are all underexpressed in lung cancer cells, into an adenoviral vector to regulate TRAIL expression. This MRE‐regulated vector (Ad‐TRAIL‐MRE) was able to express TRAIL in a lung‐cancer‐specific fashion. No TRAIL expression was detected in normal cells. Consistently, Ad‐TRAIL‐MRE exerted cytotoxicity to lung cancer cells, rather than normal cells, perhaps via inducing selective apoptosis. The selective TRAIL‐mediated growth‐inhibiting effect was further confirmed in a tumour xenograft model. Also, Ad‐TRAIL‐MRE only resulted in very low hepatotoxicity when applied. Collectively, we generated a novel TRAIL‐expressing adenoviral vector that was regulated by MREs. This strategy permits TRAIL expression in a lung‐cancer‐specific manner and is worth further studying for clinical trials. Copyright © 2014 John Wiley & Sons, Ltd.     

Assembly of a miRNA‐modified QCM sensor for miRNA recognition through response patterns

In this paper, a miRNA‐based quartz crystal microbalance (QCM) biosensor was fabricated and used to the rapid and effective sensing of miRNA. The specific hybridization between probe miRNA and different selected miRNAs (miR‐27a, miR‐27b, and Let‐7a) cause a different interaction mode, thus display different frequency change and response patterns in the QCM sensor, which were used to detect miR‐27a and miR‐27b. The selective sensing of miR‐27a in mixed miRNA solution was also achieved. This miRNA‐based QCM biosensor has the advantages of real‐time, label‐free, and short cycle detection.     

Discovery of porcine miRNA‐196a/b may influence porcine adipogenesis in longissimus dorsi muscle by miRNA sequencing

Intramuscular fat (IMF) is one of the fat traits that has economic importance in the pork industry. Longissimus dorsi muscle contains IMF and is suitable for studying adipogenesis. To discover further potential regulatory miRNAs that may influence adipogenesis, we analyzed miRNA in the longissimus dorsi muscle of Yorkshire (YY, lean‐type) and Chinese Wannanhua (WH, fatty) pigs using miRNA sequencing (miRNA‐seq). From this dataset, we identified 598 unique miRNAs comprising 325 pre‐miRNAs and 273 novel pre‐miRNAs through comparison with known miRNAs in miRBase version 21. We found 42 miRNAs including nine up‐ and 33 down‐regulated between the YY and WH pigs. Moreover, we found two miRNAs, miR‐196a/b (miR‐196a, miR‐196b‐5p), that had the highest level of expression in WH pigs, and miR‐196a/b may influence porcine adipogenesis in longissimus dorsi muscle through an adipocytokine signaling pathway.     

miRNA*生物合成及其功能研究的新发现

miRNA*是在miRNA加工成熟过程中与其互补的大约22个核苷酸的RNA序列。传统观点认为miRNA*是miRNA生物合成中形成的没有功能的副产品。然而最近的研究发现miRNA*s与miRNA一样, 主要介导转录后的基因调控网络; 但不同的是, miRNA与Argonaute1蛋白(AGO1)结合形成RNA诱导的沉默复合体(RISC), 而miRNA*却在AGO2的帮助下形成RISC复合体进行RNA干涉, 这点与siRNA的作用方式类似。文章从miRNA*的生物合成、生物学特性和功能等方面综述了miRNA*最新研究进展。     

结肠癌患者血清miRNA表达意义及与肠道菌群失调关联性

目的 探讨结肠癌患者血清miR-375、miR-21、miR-10a表达意义及与肠道菌群失调的关联性.方法 选取我院92例结肠癌患者为结肠癌组,同期92例健康体检者为对照组,测定两组不同临床特征患者血清miR-375、miR-21、miR-10a水平,并采集两组新鲜粪便标本,测定并比较大肠杆菌、双歧杆菌数量、双歧杆菌/...     

Hormone replacement therapy enhances IGF‐1 signaling in skeletal muscle by diminishing miR‐182 and miR‐223 expressions: a study on postmenopausal monozygotic twin pairs

MiRNAs are fine‐tuning modifiers of skeletal muscle regulation, but knowledge of their hormonal control is lacking. We used a co‐twin case–control study design, that is, monozygotic postmenopausal twin pairs discordant for estrogen‐based hormone replacement therapy (HRT) to explore estrogen‐dependent skeletal muscle regulation via miRNAs. MiRNA profiles were determined from vastus lateralis muscle of nine healthy 54–62‐years‐old monozygotic female twin pairs discordant for HRT (median 7 years). MCF‐7 cells, human myoblast cultures and mouse muscle experiments were used to confirm estrogen's causal role on the expression of specific miRNAs, their target mRNAs and proteins and finally the activation of related signaling pathway. Of the 230 miRNAs expressed at detectable levels in muscle samples, qPCR confirmed significantly lower miR‐182, miR‐223 and miR‐142‐3p expressions in HRT using than in their nonusing co‐twins. Insulin/IGF‐1 signaling emerged one common pathway targeted by these miRNAs. IGF‐1R and FOXO3A mRNA and protein were more abundantly expressed in muscle samples of HRT users than nonusers. In vitro assays confirmed effective targeting of miR‐182 and miR‐223 on IGF‐1R and FOXO3A mRNA as well as a dose‐dependent miR‐182 and miR‐223 down‐regulations concomitantly with up‐regulation of FOXO3A and IGF‐1R expression. Novel finding is the postmenopausal HRT‐reduced miRs‐182, miR‐223 and miR‐142‐3p expression in female skeletal muscle. The observed miRNA‐mediated enhancement of the target genes' IGF‐1R and FOXO3A expression as well as the activation of insulin/IGF‐1 pathway signaling via phosphorylation of AKT and mTOR is an important mechanism for positive estrogen impact on skeletal muscle of postmenopausal women.     

Spheroids from adipose‐derived stem cells exhibit an miRNA profile of highly undifferentiated cells

Two‐dimensional (2D) cell cultures have been extensively used to investigate stem cell biology, but new insights show that the 2D model may not properly represent the potential of the tissue of origin. Conversely, three‐dimensional cultures exhibit protein expression patterns and intercellular junctions that are more representative of their in vivo condition. Multiclonal cells that grow in suspension are defined as “spheroids,” and we have previously demonstrated that spheroids from adipose‐derived stem cells (S‐ASCs) displayed enhanced regenerative capability. With the current study, we further characterized S‐ASCs to further understand the molecular mechanisms underlying their stemness properties. Recent studies have shown that microRNAs (miRNAs) are involved in many cellular mechanisms, including stemness maintenance and proliferation, and adipose stem cell differentiation. Most studies have been conducted to identify a specific miRNA profile on adherent adipose stem cells, although little is still known about S‐ASCs. In this study, we investigate for the first time the miRNA expression pattern in S‐ASCs compared to that of ASCs, demonstrating that cell lines cultured in suspension show a typical miRNA expression profile that is closer to the one reported in induced pluripotent stem cells. Moreover, we have analyzed miRNAs that are specifically involved in two distinct moments of each differentiation, namely early and late stages of osteogenic, adipogenic, and chondrogenic lineages during long‐term in vitro culture. The data reported in the current study suggest that S‐ASCs have superior stemness features than the ASCs and they represent the true upstream stem cell fraction present in adipose tissue, relegating their adherent counterparts.     

Analysis of extracellular vesicle miRNA profiles in heart failure

Extracellular vesicles (EVs) have recently emerged as an important carrier for various genetic materials including microRNAs (miRs). Growing evidences suggested that several miRs transported by EVs were particularly involved in modulating cardiac function. However, it has remained unclear what miRs are enriched in EVs and play an important role in the pathological condition. Therefore, we established the miR expression profiles in EVs from murine normal and failing hearts and consecutively identified substantially altered miRs. In addition, we have performed bioinformatics approach to predict potential cardiac outcomes through the identification of miR targets. Conclusively, we observed approximately 63% of predicted targets were validated with previous reports. Notably, the predicted targets by this approach were often involved in both beneficial and malicious signalling pathways, which may reflect heterogeneous cellular origins of EVs in tissues. Lastly, there has been an active debate on U6 whether it is a proper control. Through further analysis of EV miR profiles, miR‐676 was identified as a superior reference control due to its consistent and abundant expressions. In summary, our results contribute to identifying specific EV miRs for the potential therapeutic targets in heart failure and suggest that miR‐676 as a new reference control for the EV miR studies.     

Disease severity–related alterations of cardiac microRNAs in experimental pulmonary hypertension

Right ventricular (RV) failure is the primary cause of death in pulmonary arterial hypertension (PAH). We hypothesized that heart‐relevant microRNAs, that is myomiRs (miR‐1, miR‐133a, miR‐208, miR‐499) and miR‐214, can have a role in the right ventricle in the development of PAH. To mimic PAH, male Wistar rats were injected with monocrotaline (MCT, 60 mg/kg, s.c.); control group received vehicle. MCT rats were divided into two groups, based on the clinical presentation: MCT group terminated 4 weeks after MCT administration and prematurely terminated group (ptMCT) displaying signs of terminal disease. Myocardial damage genes and candidate microRNAs expressions were determined by RT‐qPCR. Reduced blood oxygen saturation, breathing disturbances, RV enlargement as well as elevated levels of markers of myocardial damage confirmed PH in MCT animals and were more pronounced in ptMCT. MyomiRs (miR‐1/miR‐133a/miR‐208a/miR‐499) were decreased and the expression of miR‐214 was increased only in ptMCT group (P < 0.05). The myomiRs negatively correlated with Fulton index as a measure of RV hypertrophy in MCT group (P < 0.05), whereas miR‐214 showed a positive correlation (P < 0.05). We conclude that the expression of determined microRNAs mirrored the disease severity and targeting their pathways might represent potential future therapeutic approach in PAH.     

A functional high‐content miRNA screen identifies miR‐30 family to boost recombinant protein production in CHO cells

The steady improvement of mammalian cell factories for the production of biopharmaceuticals is a key challenge for the biotechnology community. Recently, small regulatory microRNAs (miRNAs) were identified as novel targets for optimizing Chinese hamster ovary (CHO) production cells as they do not add any translational burden to the cell while being capable of regulating entire physiological pathways. The aim of the present study was to elucidate miRNA function in a recombinant CHO‐SEAP cell line by means of a genome‐wide high‐content miRNA screen. This screen revealed that out of the 1, 139 miRNAs examined, 21% of the miRNAs enhanced cell‐specific SEAP productivity mainly resulting in elevated volumetric yields, while cell proliferation was accelerated by 5% of the miRNAs. Conversely, cell death was diminished by 13% (apoptosis) or 4% (necrosis) of all transfected miRNAs. Besides these large number of identified target miRNAs, the outcome of our studies suggest that the entire miR‐30 family substantially improves bioprocess performance of CHO cells. Stable miR‐30 over expressing cells outperformed parental cells by increasing SEAP productivity or maximum cell density of approximately twofold. Our results highlight the application of miRNAs as powerful tools for CHO cell engineering, identified the miR‐30 family as a critical component of cell proliferation, and support the notion that miRNAs are powerful determinants of cell viability.     

MicroRNAs mir‐184 and let‐7 alter Drosophila metabolism and longevity

MicroRNAs (miRNAs) are small RNA molecules that regulate gene expression associated with many complex biological processes. By comparing miRNA expression between long‐lived cohorts of Drosophila melanogaster that were fed a low‐nutrient diet with normal‐lived control animals fed a high‐nutrient diet, we identified miR‐184, let‐7, miR‐125, and miR‐100 as candidate miRNAs involved in modulating aging. We found that ubiquitous, adult‐specific overexpression of these individual miRNAs led to significant changes in fat metabolism and/or lifespan. Most impressively, adult‐specific overexpression of let‐7 in female nervous tissue increased median fly lifespan by ~22%. We provide evidence that this lifespan extension is not due to alterations in nutrient intake or to decreased insulin signaling.