Tonicity-responsive microRNAs contribute to the maximal induction of osmoregulatory transcription factor OREBP in response to high-NaCl hypertonicity

Osmotic response element binding protein (OREBP) is a Rel-like transcription factor critical for cellular osmoresponses. Previous studies suggest that hypertonicity-induced accumulation of OREBP protein might be mediated by transcription activation as well as posttranscriptional mRNA stabilization or increased translation. However, the underlying mechanisms remain incompletely elucidated. Here, we report that microRNAs (miRNAs) play critical regulatory roles in hypertonicity-induced induction of OREBP. In renal medullary epithelial mIMCD3 cells, hypertonicity greatly stimulates the activity of the 3′-untranslated region of OREBP (OREBP-3′UTR). Furthermore, overexpression of OREBP-3′UTR or depletion of miRNAs by knocking-down Dicer greatly increases OREBP protein expression. On the other hand, significant alterations in miRNA expression occur rapidly in response to high NaCl exposure, with miR-200b and miR-717 being most significantly down-regulated. Moreover, increased miR-200b or miR-717 causes significant down-regulation of mRNA, protein and transcription activity of OREBP, whereas inhibition of miRNAs or disruption of the miRNA–3′UTR interactions abrogates the silencing effects. In vivo in mouse renal medulla, miR-200b and miR-717 are found to function to tune OREBP in response to renal tonicity alterations. Together, our results support the notion that miRNAs contribute to the maximal induction of OREBP to participate in cellular responses to osmotic stress in mammalian renal cells

Posttranscriptional Regulation of Osmoregulatory Transcription Factor OREBP/NFAT5 by Tonicity-Responsive microRNAs

细胞的渗透调控（osmoregulation）是细胞最重要的生理活动之一。渗透调控转录因子OREBP/NFAT5是转录因子Rel家族的一员，是迄今为止唯一已知的能够参与哺乳动物细胞渗透压调节的转录因子。以往的研究表明，高渗（hypertonicityorhyperosmolarity）能够诱导OREBP/NFAT5mRNA和蛋白表达水平的升高，并且提升mRNA的稳定性。但是，高渗诱导的OREBP/NFAT5上调的转录后调控机制和调控因子并不清楚。在本研究中，我们对高渗透压诱导OREBP/NFAT5蛋白表达的转录后调控机制进行一系列的体内和体外实验研究。 我们发现，在小鼠肾内髓质上皮细胞mIM...Osmoregulation is one of the most essential cellular physiological activities. Osmotic response element binding protein (OREBP), also called NFAT5 (nuclear factor of the activated T cells-5) or TonEBP (tonicity-responsive element binding protein), is a Rel-like transcription factor critical for cellular osmoresponses. Previous studies suggest that hypertonicity-induced accumulation of OREBP/NFAT5 ...学位：理学博士院系专业：生命科学学院生物医学科学系_细胞生物学学号：2162007015380

CHO microRNA engineering is growing up : recent successes and future challenges

microRNAs with their ability to regulate complex pathways that control cellular behavior and phenotype have been proposed as potential targets for cell engineering in the context of optimization of biopharmaceutical production cell lines, specifically of Chinese Hamster Ovary cells. However, until recently, research was limited by a lack of genomic sequence information on this industrially important cell line. With the publication of the genomic sequence and other relevant data sets for CHO cells since 2011, the doors have been opened for an improved understanding of CHO cell physiology and for the development of the necessary tools for novel engineering strategies. In the present review we discuss both knowledge on the regulatory mechanisms of microRNAs obtained from other biological models and proof of concepts already performed on CHO cells, thus providing an outlook of potential applications of microRNA engineering in production cell lines

Genistein-Inhibited Cancer Stem Cell-Like Properties and Reduced Chemoresistance of Gastric Cancer

Key Projects of Fujian Province Technology [2010D026]; China Postdoctoral Science Foundation [2012M521279]; Medical innovations Topic in Fujian Province [2012-CXB-9]; projects of Xiamen scientific and technological plan [3502Z20124018, 3502Z20134011]Genistein, the predominant isoflavone found in soy products, has exerted its anticarcinogenic effect in many different tumor types in vitro and in vivo. Accumulating evidence in recent years has strongly indicated the existence of cancer stem cells in gastric cancer. Here, we showed that low doses of genistein (15 M), extracted from Millettia nitida Benth var hirsutissima Z Wei, inhibit tumor cell self-renewal in two types of gastric cancer cells by colony formation assay and tumor sphere formation assay. Treatment of gastric cancer cells with genistein reduced its chemoresistance to 5-Fu (fluorouracil) and ciplatin. Further results indicated that the reduced chemoresistance may be associated with the inhibition of ABCG2 expression and ERK 1/2 activity. Furthermore, genistein reduced tumor mass in the xenograft model. Together, genistein inhibited gastric cancer stem cell-like properties and reduced its chemoresistance. Our results provide a further rationale and experimental basis for using the genistein to improve treatment of patients with gastric cancer

The role of the miR-200 family in the epithelial-to-mesenchymal transition (EMT)

Over the last decade, microRNAs (miRNAs) have earned a lot of attention due to their critical roles in several biological processes and human diseases. However, progress in this field has been limited by the difficulty of discovering miRNA target genes, as each miRNA can potentially bind to hundreds of different mRNAs.(...

Shared Genetic Architecture of Red Blood Cell Traits in U.S. Populations

Red blood cells are the most numerous cell in the body, and clinical measures used to describe them (RBC traits) are highly polygenic. Hundreds of loci have been identified using traditional genome-wide association study methods. However, the majority of association studies have been performed in European- or East Asian-ancestry populations, and heritability estimates suggest that additional associations remain to be identified. Rare variants, which GWAS are typically underpowered to detect, have been considered as potential contributors to this missing heritability. Of note, European-ancestry populations have both the lowest genetic diversity and the fewest rare variants compared to other ancestry groups. Both the identification of previously unreported loci and the characterization of known loci for complex quantitative traits benefit from inclusive study populations and recently developed association study methods. The objective of this study was to evaluate genetic associations with seven RBC traits in an ancestrally diverse study population by applying two different methods—a combined-phenotype approach to evaluating common variants that may affect multiple RBC traits, and a gene-based approach that improves power to detect groups of rare variants acting on a single genetic transcript. We utilized data from a large, multi-ethnic study population from across the United States, including genotypes and data from seven RBC traits: hematocrit, hemoglobin concentration, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, mean corpuscular volume, red blood cell count, and red cell distribution width. Our findings confirm the high polygenicity of RBC traits and the applicability of previously reported RBC trait loci to populations of all ancestries. We identified four previously unreported genes associated with one or more RBC traits. Additionally, using a combined-phenotype method we identified twenty independent association signals within seven loci, several of which had lead variants only present in African- or American-ancestry populations. Our work shows the importance of performing association studies in populations of all ancestries, while also calling for increased representation of genetic variation from diverse populations in publicly available resources such as eQTL databases. Continued efforts into the bioinformatic characterization of RBC trait loci will pave the way for molecular work that improves our understanding of RBC physiology and may lead to pharmaceutical innovations for genetically or environmentally induced RBC disorders.Doctor of Philosoph