Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Timed regulation of Piwi-interacting RNAs expression during rat liver regeneration

ABSTRACT: Small noncoding (snc) RNAs represent a growing family of transcripts that regulate key cellular processes, including mRNA degradation, translational repression and transcriptional gene silencing. Among these, the PIWI-interacting RNAs (piRNAs), a major class of sncRNAs initially identified in the germline of a variety of species, are now being found to be functionally active also in somatic cells. However, whether the Piwi/piRNA pathway is associated with fundamental biological processes, such as cell cycle progression, remains elusive. Here we investigated the possibility that piRNAs are expressed in liver and modulated during regenerative proliferation of this organ. To this aim, smallRNA-Seq was applied to identify and quantitate expression of these RNAs in rat liver before, during and after the wave of cell proliferation that follows partial hepatectomy (PH). Q-PCR analysis revealed the presence in rat liver of two PIWI (PIWI-Like) subfamily members (PIWIL2/HILI and, to a much lower level, PIWIL4/HIWI2) and other components of the piRNA biogenesis pathways, suggesting that this is present and functional in hepatocytes. Indeed, ~1400 piRNAs originally identified in rat and other mammalian germline cells are expressed in adult rat liver, including 72 that show timed changes in expression during cell cycle progression. Most piRNAs are up-regulated 24-48h after hepatectomy, a timing that corresponds to cell transition through the S phase, and return to basal levels by 168 h, when organ regeneration is completed and hepatocytes reach quiescence. These results indicate that the piRNA pathway is active in somatic cells and, more important, that it is subject to regulation during physiological processes, such as cell proliferation, when piRNAs may exert their regulatory functions on the cell genome and transcriptome. smallRNA-Seq was applied to identify and quantitate expression of RNAs in rat liver before and after partial hepatectomy (PH).

ORGANISM(S): Rattus norvegicus

SUBMITTER: Adnan Hashim

PROVIDER: E-GEOD-55783 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Timed regulation of P-element-induced wimpy testis-interacting RNA expression during rat liver regeneration.

Rizzo Francesca F Hashim Adnan A Marchese Giovanna G Ravo Maria M Tarallo Roberta R Nassa Giovanni G Giurato Giorgio G Rinaldi Antonio A Cordella Angela A Persico Marcello M Sulas Pia P Perra Andrea A Ledda-Columbano Giovanna M GM Columbano Amedeo A Weisz Alessandro A

Hepatology (Baltimore, Md.) 20140701 3

<h4>Unlabelled</h4>Small noncoding RNAs comprise a growing family of molecules that regulate key cellular processes, including messenger RNA (mRNA) degradation, translational repression, and transcriptional gene silencing. P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) represent a class of small RNAs initially identified in the germline of a variety of species, where they contribute to maintenance of genome stability, and recently found expressed also in stem and somatic cells, ...[more]

PMID: 24930433

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Project description:PIWI-interacting RNAs (piRNAs) are a novel class of small ncRNAs initially isolated from germ line cells; although recent studies report that they are expressed also in somatic cells. To elucidate the role of piRNAs in somatic cells, in particular from breast cancer, we performed the first extensive next generation sequencing expression analysis of small RNA transcriptomes of hormone responsive breast cancer cell lines in different culture conditions. In addition, to understand the behavior of piRNAs with respect to miRNAs in breast tumor tissues, small RNA sequence data set available in Gene Expression Omnibus (GSE39162) database was used. Results led to the identification of ~100 and ~150 human piRNAs in the breast cancerous cell lines and tumors respectively, several of which differentially expressed in cell lines under different experimental conditions tested or in response to ERβ and in tumor tissues. Western blotting and Q-PCR analysis also revealed the presence in breast cell lines of PIWIL (PIWI Like) subfamily members proteins encoded in the human genome (PIWIL2/HILI and PIWIL4/HIWI2) and of other components of the piRNA biogenesis pathways, suggesting that this might indeed be functional in somatic cells. These results show that piRNAs are expressed in human somatic cells, in particular in cancer, where their expression is influenced by neoplastic transformation, growth conditions and estrogen receptor beta. More important, we demonstrate for the first time a distinct pattern of piRNAs expression in cancerous vs normal breast tissues, which suggests a potential role of these epigenetic modulators in mammary carcinogenesis and maintenance of the cancer cell phenotype. In addition, to understand the behavior of piRNAs with respect to miRNAs in breast tumor tissues, small RNA sequence data set available in Gene Expression Omnibus (GEO; GSM957192 TAX577740T ,GSM957194 TAX577740N, GSM957195 TAX577453T, GSM957197 TAX577453N, GSM957198 TAX577745T, GSM957200 TAX577745N, GSM957201 TAX577579T, GSM957203 TAX577579N) was used.

Project description:The piRNA pathway is studied in great detail in Drosophila female germline. In this study we show that unlike the female germline where all Piwi proteins are expressed throughout oogenesis, Ago3 - a Piwi family protein shows a spatial expression male germline. To understand dynamics of piRNA pathway during spermatogonia and primary spermatocyte stages of male germline development, we used arrest mutants. The bag of marbles (bam) and benign gonial cell neoplasm (bgcn) mutants have only early mitotic dividing germline cells in the testes due to failure to progress to primary spermatocyte stage, the cannonball (can) and spermatocyte arrest (sa) mutant germline cells cannot progress beyond primary spermatocyte stage. To investigate the dynamics of the piRNA pathway during spermatogenesis in spermatogonia and primary spermatocyte stages, we used testicular tissues from these stage-specific arrested mutants. While we used entire bam and bgcn mutant testes for spermatogonia purification, we while we manually removed the apical regions of can and sa mutant testes to exclude mitotically dividing undifferentiated germline cells for primary spermatocytes purification. Our results show that piRNAs mapping to transposons are more abundant in spermatogonia, whereas those mapping to Suppressor of Stellate [Su(Ste)] and AT-chX are mostly expressed in primary spermatocytes. Furthermore we observed that transposon-mapping piRNAs with ping-pong signature are more abundant in spermatogonia albeit still detectable in primary spermatocytes where Ago3 is not expressed. These results suggest that robust piRNA production via ping-pong cycle takes place in spermatogonia, and to a lesser extent in primary spermatocytes even in the absence of Ago3. Consistently, piRNAs from ago3 mutant testes also exhibit the ping-pong signature, confirming that a non-canonical ping-pong cycle is acting during spermatogenesis. Our study provides a developmental dimension to the piRNA pathway and uncovers a new mechanism used in the male germline to silence transposons. The difference in piRNA from spermatogonia and primary spermatocyte stages was studied by comparing small RNAs from bam and bgcn mutant testis, which represent spermatogonia stages with the small RNAs from apex removed can and sa testis, representing primary spermatocyte stages. In the study we also studied effect of loss of Piwi family proteins Aub and Ago3, which have different spatial expression during male germline development.

Dataset Information

Timed regulation of Piwi-interacting RNAs expression during rat liver regeneration

Publications

Timed regulation of P-element-induced wimpy testis-interacting RNA expression during rat liver regeneration.

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