Background & Aims: Spasmolytic polypeptide/TFF2-expressing metaplasia (SPEM) is known to emerge following parietal cell loss and during Helicobacter pylori infection, however its role in gastric ulcer repair is unknown. Therefore, we sought to investigate if SPEM plays a role in epithelial regeneration. Methods: Acetic acid ulcers were induced in young (2-3 months) C57BL/6 mice to determine the quality of ulcer repair. Gastric tissue was collected and analyzed to determine the expression of SPEM within the regenerating epithelium. As a comparison to native tissue the expression of SPEM was also identified within cultured gastric mouse-derived organoids. Results: Wound healing in the mice coincided with the emergence of SPEM expressing CD44v within the ulcerated region. The emergence of SPEM was also observed in cultured gastric organoids. Conclusions: These data demonstrate the SPEM may play a role in epithelial regeneration. Conclusions: These data demonstrate the SPEM may play a role in epithelial regeneration. Overall design: 4 samples were used for ulcerated and uninjured tissue. 1 sample was used for intact tissue and organoid-derived RNA. The 'Ulcerated' samples represent C57BL/6 mice with ulcers and the 'Uninjured' samples represent the healthy controls (for "ulcerated" samples). The "Intact stomach tissue" and "Gastric organoids" samples are other types of samples that compared separately. "Gastric organoids" in this comparison are derived from "Intact stomach tissue".
The Development of Spasmolytic Polypeptide/TFF2-Expressing Metaplasia (SPEM) During Gastric Repair Is Absent in the Aged Stomach.
Specimen part, Cell line, Subject
View SamplesIt has been recently shown that N-ras plays a preferential role in immune cell development and function; specifically: N-ras, but not H-ras or K-ras, could be activated at and signal from the Golgi membrane of immune cells following a low level TCR stimulus. The goal of our studies was to test the hypothesis that N-ras and H-ras played distinct roles in immune cells at the level of the transcriptome.
In TCR-stimulated T-cells, N-ras regulates specific genes and signal transduction pathways.
Specimen part, Treatment
View SamplesHematopoietic stem and progenitor cells are a rare, self-renewing bone marrow resident population capable of giving rise to all circulating hematopoietic cells. They can be used therapuetically for reconstituting defective or ablated hematopoietic systems following chemotherapy, and for inducing tolerance toward allografts of the same haplotype as the HSC donor. There are several sources for HSCs, such as the adult bone marrow, or umblical cord blood, which is more replete with such HSCs. However, HSCs obtained from such sources may be immunogenic, especially if isolated from adult bone marrow. To overcome this issue, our lab has establsihed human induced pluripotent stem cell-derived HPCs with the hope of creating a nonimmunogenic, readily available and unlimited source of HSCs to use for therapy.
Human iPS cell-derived hematopoietic progenitor cells induce T-cell anergy in in vitro-generated alloreactive CD8(+) T cells.
Disease
View SamplesThe cellular response to DNA damage is mediated through multiple pathways that regulate and coordinate DNA repair, cell cycle arrest and cell death. We show that the DNA damage response (DDR) induced by ionizing radiation (IR) is coordinated in breast cancer cells by selective mRNA translation mediated by high levels of translation initiation factor eIF4G1. Increased expression of eIF4G1, common in breast cancers, was found to selectively increase translation of mRNAs involved in cell survival and the DDR, preventing autophagy and apoptosis (Survivin, HIF1, XIAP), promoting cell cycle arrest (GADD45a, p53, ATRIP, Chk1) and DNA repair (53BP1, BRCA1/2, PARP, Rfc2-5, ATM, MRE-11, others). Reduced expression of eIF4G1, but not its homolog eIF4G2, greatly sensitizes cells to DNA damage by IR, induces cell death by both apoptosis and autophagy, and significantly delays resolution of DNA damage foci with little reduction of overall protein synthesis. While some mRNAs selectively translated by higher levels of eIF4G1 were found to use internal ribosome entry site (IRES)-mediated alternate translation, most do not. The latter group shows significantly reduced dependence on eIF4E for translation, facilitated by an enhanced requirement for eIF4G1. Increased expression of eIF4G1 therefore promotes specialized translation of survival, growth arrest and DDR mRNAs that are important in cell survival and DNA repair following genotoxic DNA damage.
DNA damage and eIF4G1 in breast cancer cells reprogram translation for survival and DNA repair mRNAs.
Cell line
View SamplesEndometrial receptivity on genomic level is one of the major cause of implantation failure in IVF patients with unexlained infertility and is a main obstacle in success of IVF. Gene expression profiles of implantation failure cases of unexplained infertility were compared with proven healthy oocyte donors as controls, both undergoing ovarian stimulation. The results provide additional information about gene expression profile related to endometrial receptivity in implantation failure cases especially under the influence of ovarian stimulation during IVF cycle.
Downregulation of genes related to immune and inflammatory response in IVF implantation failure cases under controlled ovarian stimulation.
Age, Specimen part
View SamplesIn eukaryotes, the 3'' ends of RNA polymerase II-generated transcripts are made in the majority of cases by site-specific endonucleolytic cleavage, followed by the addition of a poly(A) tail. By alternative polyadenylation, a gene can give rise to multiple mRNA isoforms that differ in the length of their 3'' UTRs and hence in their susceptibility to post-transcriptional regulatory factors such as microRNAs. A series of recently conducted high-throughput studies of poly(A) site usage revealed an extensive tissue-specific control of 3’ UTR length and drastic changes in 3’ UTR length of mRNAs upon induction of proliferation in resting cells. To understand the dynamics of polyadenylation site usage, we recently identified binding sites of the major pre-mRNA 3’ end processing factors - cleavage and polyadenylation specificity factor (CPSF), cleavage stimulation factor (CstF), and cleavage factor Im (CF Im) - and mapped cleaved polyadenylation sites in HEK293 cells. Our present study extends previous findings on the role of CF Im in alternative polyadenylation and reveals that subunits of the CF Im complex generally control 3’ UTR length. More specifically, we demonstrate that the loss-of-function of CF Im68 and CF Im25 but not of CF Im59 leads to a transcriptome-wide increase of the use of proximal polyadenylation sites. Overall design: 3'' ends of transcripts were profiled by high-throughput sequencing in HEK 293 cells under normal conditions, and in HEK 293 cells depleted of 3'' end processing factors CF Im25, CF Im59, and CF Im68.
Cleavage factor Im is a key regulator of 3' UTR length.
Cell line, Subject
View SamplesThe RNA helicase UPF1 is best known for its key function in mRNA nonsense-mediated mRNA decay (NMD), but has also been implicated in additional mRNA turnover mechanisms, telomere homeostasis, and DNA replication. In NMD, UPF1 recruitment to target mRNAs is thought to occur through interaction with release factors at terminating ribosomes, but evidence for translation-independent interaction of UPF1 with the 3’ untranslated region (UTR) of mRNAs has also been reported. To map UPF1 binding sites transcriptome-wide, we performed individual-nucleotide resolution UV crosslinking and immunoprecipitation (iCLIP) in human cells, untreated or after inhibiting translation by puromycin. We found a strong association of UPF1 with 3’ UTRs in undisturbed, translationally active cells and a significant increase in UPF1 binding to coding sequence (CDS) after translation inhibition. These results indicate that UPF1 binds RNA before translation and gets displaced from the CDS by translating ribosomes. This evidence for translation-independent UPF1-RNA interaction, which is corroborated by RNA immunoprecipitations experiments and by our observation that UPF1 also crosslinks to long non-coding RNAs, suggests that the decision to trigger NMD occurs after association of UPF1 with the mRNA, presumably through activation of RNA-bound UPF1 by aberrant translation termination. Overall design: Examination of Upf1 binding preferences via iCLIP in untreated HeLa cells and HeLa cells, where translation is blocked by puromycin treatment in vivo crosslinking and immunoprecipitation strategy (iCLIP)
Translation-dependent displacement of UPF1 from coding sequences causes its enrichment in 3' UTRs.
Cell line, Subject
View SamplesThrough alternative polyadenylation, human mRNAs acquire longer or shorter 3'' untranslated regions, the latter typically associated with higher transcript stability and increased protein production. To understand the dynamics of polyadenylation site usage, we mapped transcriptome-wide both binding sites of 3'' end processing factors CPSF-160, CPSF-100, CPSF-73, CPSF-30, Fip1, CstF-64, CstF-64tau, CF Im25, CF Im59, and CF Im68 and 3'' end processing sites in HEK293 cells. We found that although binding sites of these factors generally cluster around the poly(A) sites most frequently used in cleavage, CstF-64/CstF-64tau and CF Im proteins have much higher positional specificity compared to CPSF components. Knockdown of CF Im68 induced a systematic use of proximal polyadenylation sites, indicating that changes in relative abundance of a single 3'' end processing factor can modulate the length of 3'' untranslated regions transcriptome-wide, and suggesting a mechanism behind the previously observed increase in tumor cell invasiveness upon CF Im68 knockdown. Overall design: 3'' ends of transcripts were profiled by high-throughput sequencing in HEK 293 cells under normal conditions, and in HEK 293 cells depleted of 3'' end processing factors CF Im 68 and CstF-64.
Genome-wide analysis of pre-mRNA 3' end processing reveals a decisive role of human cleavage factor I in the regulation of 3' UTR length.
Cell line, Subject
View SamplesWe analyzed small RNAs from three mammalian species, and found that in all these species piRNA-directed targeting is accompanied by the generation of short sequences that have a very precisely defined length and a specific spatial relationship with the guide piRNAs. Overall design: small RNA-seq of testes lysate (beta-eliminated)
Conserved generation of short products at piRNA loci.
No sample metadata fields
View SamplesRelative contribution of sequence and structural features to the mRNA-binding of Argonaute/miRNA complexes and the degradation of miRNA targets
Relative contribution of sequence and structure features to the mRNA binding of Argonaute/EIF2C-miRNA complexes and the degradation of miRNA targets.
No sample metadata fields
View Samples