MicroRNA Expression Profiling of Multipotent Adult Germline Stem Cells

Es wurde gezeigt, dass Spermatogoniale Stammzellen (SSCs), die aus adulten Mäusehoden isoliert werden, durch Kulturbedingungen pluripotent werden und als "multipotent adult germline stem cells" (maGSCs) bezeichnet werden. Vor einiger Zeit wurde eine Gruppe nicht codierender RNAs identifiziert, die sogenannte microRNAs (miRNAs), die eine Schlüsselrolle in der embryonalen Entwicklung und Pluripotenz von Embryonalen Stammzellen (ESCs) spielen. Das Ziel dieser Arbeit war es, Ähnlichkeiten und Unterschiede zwischen maGSCs und ESCs im Bezug auf miRNAs zu untersuchen. Ein Gesamt-miRNA Array zeigte trotz geringen Unterschieden in der Expression von einigen Oncomirs, dass undifferenzierte maGSCS und ESCs aus einem 129/Sv Hintergrund sich in ihrem microRNAome kaum unterscheiden. Im Gegensatz dazu unterscheiden sich undifferenzierte maGSCs aus der transgenen Stra8-EGFP-Rosa-Maus von allen anderen untersuchten Zelltypen. miRNAs, der 290 und 302 Familie, sind als ESC spezifisch bekannt. In dieser Arbeit konnte gezeigt werden, dass diese miRNAs neben undifferenzierten ESCs auch in anderen pluripotenten Zelllinien, wie maGSCs und in F9 Zellen (Embryonale Karzinoma Zellen; ECCs) exprimiert werden. Ausserdem wurde der zeitabhängige Einfluss verschiedener Faktoren, die den Verlust von Pluripotenz fördern, auf diese miRNAs untersucht. ESCs, die mit Hilfe von Standardmethoden

A Unique Combination of Male Germ Cell miRNAs Coordinates Gonocyte Differentiation

The last 100 years have seen a concerning decline in male reproductive health associated with decreased sperm production, sperm function and male fertility. Concomitantly, the incidence of defects in reproductive development, such as undescended testes, hypospadias and testicular cancer has increased. Indeed testicular cancer is now recognised as the most common malignancy in young men. Such cancers develop from the pre-invasive lesion Carcinoma in Situ (CIS), a dysfunctional precursor germ cell or gonocyte which has failed to successfully differentiate into a spermatogonium. It is therefore essential to understand the cellular transition from gonocytes to spermatogonia, in order to gain a better understanding of the aetiology of testicular germ cell tumours. MicroRNA (miRNA) are important regulators of gene expression in differentiation and development and thus highly likely to play a role in the differentiation of gonocytes. In this study we have examined the miRNA profiles of highly enriched populations of gonocytes and spermatogonia, using microarray technology. We identified seven differentially expressed miRNAs between gonocytes and spermatogonia (down-regulated: miR-293, 291a-5p, 290-5p and 294*, up-regulated: miR-136, 743a and 463*). Target prediction software identified many potential targets of several differentially expressed miRNA implicated in germ cell development, including members of the PTEN, and Wnt signalling pathways. These targets converge on the key downstream cell cycle regulator Cyclin D1, indicating that a unique combination of male germ cell miRNAs coordinate the differentiation and maintenance of pluripotency in germ cells

MicroRNA profiling of rhesus macaque embryonic stem cells

<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs) play important roles in embryonic stem cell (ESC) self-renewal and pluripotency. Numerous studies have revealed human and mouse ESC miRNA profiles. As a model for human-related study, the rhesus macaque is ideal for delineating the regulatory mechanisms of miRNAs in ESCs. However, studies on rhesus macaque (r)ESCs are lacking due to limited rESC availability and a need for systematic analyses of fundamental rESC characteristics.</p> <p>Results</p> <p>We established three rESC lines and profiled microRNA using Solexa sequencing resulting in 304 known and 66 novel miRNAs. MiRNA profiles were highly conserved between rESC lines and predicted target genes were significantly enriched in differentiation pathways. Further analysis of the miRNA-target network indicated that gene expression regulated by miRNAs was negatively correlated to their evolutionary rate in rESCs. Moreover, a cross-species comparison revealed an overall conservation of miRNA expression patterns between human, mouse and rhesus macaque ESCs. However, we identified three miRNA clusters (miR-467, the miRNA cluster in the imprinted Dlk1-Dio3 region and C19MC) that showed clear interspecies differences.</p> <p>Conclusions</p> <p>rESCs share a unique miRNA set that may play critical roles in self-renewal and pluripotency. MiRNA expression patterns are generally conserved between species. However, species and/or lineage specific miRNA regulation changed during evolution.</p

Involvement of microRNA Lethal-7a in the Regulation of Embryo Implantation in Mice

MicroRNAs interact with multiple mRNAs resulting in their degradation and/or translational repression. This report used the delayed implantation model to determine the role of miRNAs in blastocysts. Dormant blastocysts in delayed implanting mice were activated by estradiol. Differential expression of 45 out of 238 miRNAs examined was found between the dormant and the activated blastocysts. Five of the nine members of the microRNA lethal-7 (let-7) family were down-regulated after activation. Human blastocysts also had a low expression of let-7 family. Forced-expression of a family member, let-7a in mouse blastocysts decreased the number of implantation sites (let-7a: 1.1±0.4; control: 3.8±0.4) in vivo, and reduced the percentages of blastocyst that attached (let-7a: 42.0±8.3%; control: 79.0±5.1%) and spreaded (let-7a: 33.5±2.9%; control: 67.3±3.8%) on fibronectin in vitro. Integrin-β3, a known implantation-related molecule, was demonstrated to be a target of let-7a by 3′-untranslated region reporter assay in cervical cancer cells HeLa, and Western blotting in mouse blastocysts. The inhibitory effect of forced-expression of let-7a on blastocyst attachment and outgrowth was partially nullified in vitro and in vivo by forced-expression of integrin-β3. This study provides the first direct evidence that let-7a is involved in regulating the implantation process partly via modulation of the expression of integrin-β3. (200 words)

Manufacturing study of an orthopaedic implants family of type LCP on a CNC machining center

Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Συστήματα Αυτοματισμού

Dilated cardiomyopathy during the course of hemolytic uremic syndrome

A 47-year-old woman presented with severe hemolytic uremic syndrome (HUS) followed by heart failure. An echocardiogram showed an ejection fraction of 20%, and a cardiac catheterization followed by a myocardial histologic evaluation demonstrated dilated cardiornyopathy. Plasma exchange and hemodialysis were performed regularly. The later outcomes of renal function and cardiomyopathy were favorable. A review of the literature confirmed the rare and severe nature of cardiac lesions occurring in the course of HUS. This case indicates the importance of cardiac monitoring in HUS and the need for prolonged support