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

Members of the miR-290 cluster modulate in vitro differentiation of mouse embryonic stem cells

We report the biological effects of miR-290 cluster via gain-of-function or loss-of-function experiments in mouse embryonic stem cells (ESCs) cultured under differentiation conditions. Under these conditions we found that overexpression of miR-290 cluster in ESCs cannot prevent downregulation of Oct-4, but inhibition results in earlier down regulation of Oct-4 compared with the negative control. In consistence with previous findings that report ectopic expression of Brachyury during gastrulation in Argonaute-2 KO mice due to impaired miRNA function, we show that miR-290 cluster regulates negatively differentiation of ESCs towards mesodermal and germ cell lineage. These results suggest that although incapable to maintain pluripotent state alone, miR-290 cluster inhibits ESC differentiation and it is involved in the pathways controlling mesoderm and primordial germ cell differentiation. Finally, we provide proofs that members of this cluster target Dkk-1 gene, a Wnt pathway inhibitor, and affect this pathway, which can partially explain why miR-290 cluster favours pluripotency against differentiation. (C) 2009 International Society of Differentiation. Published by Elsevier Ltd. All rights reserved

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

The expression level of small non-coding RNAs derived from the first exon of protein-coding genes is predictive of cancer status

Small non-coding RNAs (smRNAs) are known to be significantly enriched near the transcriptional start sites of genes. However, the functional relevance of these smRNAs remains unclear, and they have not been associated with human disease. Within the cancer genome atlas project (TCGA), we have generated small RNA datasets for many tumor types. In prior cancer studies, these RNAs have been regarded as transcriptional "noise," due to their apparent chaotic distribution. In contrast, we demonstrate their striking potential to distinguish efficiently between cancer and normal tissues and classify patients with cancer to subgroups of distinct survival outcomes. This potential to predict cancer status is restricted to a subset of these smRNAs, which is encoded within the first exon of genes, highly enriched within CpG islands and negatively correlated with DNA methylation levels. Thus, our data show that genome-wide changes in the expression levels of small non-coding RNAs within first exons are associated with cancer. Synopsis The expression of small non-coding RNAs encoded within the first exon of genes can be used to efficiently identify cancer samples and classify patients into subgroups of different survival. Such pan-cancer association is the first link between these RNAs and disease. Exon 1 small non-coding RNAs (smRNAs) can distinguish between cancer and normal tissues. The prediction potential of exon 1 smRNAs differs from that of other smRNAs around transcriptional start sites (TSS). smRNA locations around TSS are conserved between different individuals. smRNA locations are enriched within CpG islands and their levels negatively correlated with DNA methylation. The expression of small non-coding RNAs encoded within the first exon of genes can be used to efficiently identify cancer samples and classify patients into subgroups of different survival. Such pan-cancer association is the first link between these RNAs and disease. © 2014 The Authors

Depletion of eukaryotic initiation factor 5B (eIF5B) reprograms the cellular transcriptome and leads to activation of endoplasmic reticulum (ER) stress and c-Jun N-terminal Kinase (JNK).

Permission to archive accepted author manuscript. Embargo in effect until Oct 29, 2021.During the integrated stress response (ISR), global translation initiation is attenuated; however, noncanonical mechanisms allow for the continued translation of specific transcripts. Eukaryotic initiation factor 5B (eIF5B) has been shown to play a critical role in canonical translation as well as in noncanonical mechanisms involving internal ribosome entry site (IRES) and upstream open reading frame (uORF) elements. The uORF-mediated translation regulation of activating transcription factor 4 (ATF4) mRNA plays a pivotal role in the cellular ISR. Our recent study confirmed that eIF5B depletion removes uORF2-mediated repression of ATF4 translation, which results in the upregulation of growth arrest and DNA damage-inducible protein 34 (GADD34) transcription. Accordingly, we hypothesized that eIF5B depletion may reprogram the transcriptome profile of the cell. Here, we employed genome-wide transcriptional analysis on eIF5B-depleted cells. Further, we validate the up- and downregulation of several transcripts from our RNA-seq data using RT-qPCR. We identified upregulated pathways including cellular response to endoplasmic reticulum (ER) stress, and mucin-type O-glycan biosynthesis, as well as downregulated pathways of transcriptional misregulation in cancer and T cell receptor signaling. We also confirm that depletion of eIF5B leads to activation of the c-Jun N-terminal kinase (JNK) arm of the mitogen-activated protein kinase (MAPK) pathway. This data suggests that depletion of eIF5B reprograms the cellular transcriptome and influences critical cellular processes such as ER stress and ISR.Ye

Genomic Characterization of Carbapenem-Resistant Bacteria from Beef Cattle Feedlots

Carbapenems are considered a last resort for the treatment of multi-drug-resistant bacterial infections in humans. In this study, we investigated the occurrence of carbapenem-resistant bacteria in feedlots in Alberta, Canada. The presumptive carbapenem-resistant isolates (n = 116) recovered after ertapenem enrichment were subjected to antimicrobial susceptibility testing against 12 different antibiotics, including four carbapenems. Of these, 72% of the isolates (n = 84) showed resistance to ertapenem, while 27% of the isolates (n = 31) were resistant to at least one other carbapenem, with all except one isolate being resistant to at least two other drug classes. Of these 31 isolates, 90% were carbapenemase positive, while a subset of 36 ertapenem-only resistant isolates were carbapenemase negative. The positive isolates belonged to three genera; Pseudomonas, Acinetobacter, and Stenotrophomonas, with the majority being Pseudomonas aeruginosa (n = 20) as identified by 16S rRNA gene sequencing. Whole genome sequencing identified intrinsic carbapenem resistance genes, including blaOXA-50 and its variants (P. aeruginosa), blaOXA-265 (A. haemolyticus), blaOXA-648 (A. lwoffii), blaOXA-278 (A. junii), and blaL1 and blaL2 (S. maltophilia). The acquired carbapenem resistance gene (blaPST-2) was identified in P. saudiphocaensis and P. stutzeri. In a comparative genomic analysis, clinical P. aeruginosa clustered separately from those recovered from bovine feces. In conclusion, despite the use of selective enrichment methods, finding carbapenem-resistant bacteria within a feedlot environment was a rarity

Comparative Genomic Analysis of Enterococci across Sectors of the One Health Continuum

Enterococci are Gram-positive bacteria that can be isolated from a variety of environments including soil, water, plants, and the intestinal tract of humans and animals. Although they are considered commensals in humans, Enterococcus spp. are important opportunistic pathogens. Due to their presence and persistence in diverse environments, Enterococcus spp. are ideal for studying antimicrobial resistance (AMR) from the One Health perspective. We undertook a comparative genomic analysis of the virulome, resistome, mobilome, and the association between the resistome and mobilome of 246 E. faecium and 376 E. faecalis recovered from livestock (swine, beef cattle, poultry, dairy cattle), human clinical samples, municipal wastewater, and environmental sources. Comparative genomics of E. faecium and E. faecalis identified 31 and 34 different antimicrobial resistance genes (ARGs), with 62% and 68% of the isolates having plasmid-associated ARGs, respectively. Across the One Health continuum, tetracycline (tetL and tetM) and macrolide resistance (ermB) were commonly identified in E. faecium and E. faecalis. These ARGs were frequently associated with mobile genetic elements along with other ARGs conferring resistance against aminoglycosides [ant(6)-la, aph(3′)-IIIa], lincosamides [lnuG, lsaE], and streptogramins (sat4). Study of the core E. faecium genome identified two main clades, clade ‘A’ and ‘B’, with clade A isolates primarily originating from humans and municipal wastewater and carrying more virulence genes and ARGs related to category I antimicrobials. Overall, despite differences in antimicrobial usage across the continuum, tetracycline and macrolide resistance genes persisted in all sectors