In response to external and internal signals, mammalian cells elicit post-transcriptional changes in gene expression patterns that govern the global cellular response. We are keenly interested in the mechanisms that regulate the expression of proliferative, cell cycle-regulatory, and stress-response proteins. Over the past 16 years, this Project has examined numerous RBPs, noncoding (nc)RNAs, and their influence on gene expression patterns. We have paid particular attention to their influence on the stress and proliferative response of cells, two processes that are severely impaired during aging. In the past funding period, we have continued to focus on RBPs implicated in the cellular response to mitogens and stresses, but have expanded substantially into ncRNAs that influence these responses. Since impaired adaptation to mitogens and cell injury underlie various cancer traits (cell proliferation and survival, angiogenesis, invasion, metastasis, and evasion of immune recognition), most studies in this project use cancer cells as the model system. Proliferation and stress response. We have continued to investigate the influence of HuR on cell division. During this review period, we studied several post-transcriptional and post-translational mechanisms controlling HuR expression and function. We have also continued to study the role of HuR on the cellular response to damaging agents. Exposure to the oxidant hydrogen peroxide, to nitric oxide and to hypoxia regulated HuR activity. In an animal model of surgical stress, HuR competed with the RBP CUGBP1 (CUG-binding protein 1) to drive expression of occludin, as documented in collaborative studies (Yu et al., Mol Biol Cell, 2013). Tumorigenesis. The ability of HuR to promote tumorigenic traits continued to be revealed during this review period. Collaborative studies lent support to the notion that HuR competes with miR-195 to modulate Stim1 production and thereby regulate cell migration Zhuang et al., Nuc. Acids Res 2013. Numerous ncRNAs that suppress tumorigenesis were also studied during this funding period. Tumor-suppressor microRNAs, including several that trigger senescence (e.g., let-7, miR-34, and miR-519), were recently reviewed and discussed (Grammatikakis et al., Intl J Med Sci, 2013). The expression and stability of the long intergenic noncoding (linc)RNA-p21 were negatively regulated by HuR;since lincRNA-p21 repressed the translation of the anti-apoptotic proteins JunB and -catenin, HuR further promoted a pro-survival phenotype through its influence on lincRNA-p21 (Yoon et al., Mol Cell, 2012). This work inspired a review that summarized the post-transcriptional regulation of lncRNAs thus far (Yoon et al., J Mol Biol, 2012). Additional work was done during this review period in order to fully characterize the RBPs and ncRNAs involved in cancer, proliferation, stress-response, senescence, and other processes relevant to aging. Loss of the RBP AUF1 in cells accelerated senescence, while AUF1-null mice showed premature aging. However, the systematic collection of AUF1-associated mRNAs is not fully known;moreover, since AUF1 represses Dicer expression, AUF1 appears to affect broadly the profiles of expressed microRNAs (Abdelmohsen et al., Nuc Acids Res 2012). Nucleolin also has a wide spectrum of functions, including carcinogenesis (Abdelmohsen and Gorospe, RNA Biol, 2012), but the subset of bound mRNAs was only recently identified (Abdelmohsen et al., Nuc Acids Res, 2013). Given that nucleolin expression is regulated through competition between HuR and miR-494, we recently reviewed the interplay between HuR and microRNAs (Srikantan et al., Curr Prot Pept Sci 2012). Finally, we have reported several methodologies, among which are a technique to screen for factors associated in an RNA of interest that is tagged with MS2 hairpins (Yoon et al., Methods, 2012) and a method to measure the levels of functional microRNAs (Guo et al., PLoS ONE, 2013).

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
1ZIAAG000511-16
Application #
8736569
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
16
Fiscal Year
2013
Total Cost
$484,130
Indirect Cost
Name
National Institute on Aging
Department
Type
DUNS #
City
State
Country
Zip Code
Yoon, Je-Hyun; Gorospe, Myriam (2016) Cross-Linking Immunoprecipitation and qPCR (CLIP-qPCR) Analysis to Map Interactions Between Long Noncoding RNAs and RNA-Binding Proteins. Methods Mol Biol 1402:11-7
Dudekula, Dawood B; Panda, Amaresh C; Grammatikakis, Ioannis et al. (2016) CircInteractome: A web tool for exploring circular RNAs and their interacting proteins and microRNAs. RNA Biol 13:34-42
Zou, Tongtong; Jaladanki, Suraj K; Liu, Lan et al. (2016) H19 Long Noncoding RNA Regulates Intestinal Epithelial Barrier Function via MicroRNA 675 by Interacting with RNA-Binding Protein HuR. Mol Cell Biol 36:1332-41
Grammatikakis, Ioannis; Abdelmohsen, Kotb; Gorospe, Myriam (2016) Posttranslational control of HuR function. Wiley Interdiscip Rev RNA :
Xiao, Lan; Rao, Jaladanki N; Cao, Shan et al. (2016) Long noncoding RNA SPRY4-IT1 regulates intestinal epithelial barrier function by modulating the expression levels of tight junction proteins. Mol Biol Cell 27:617-26
Cascajo, María V; Abdelmohsen, Kotb; Noh, Ji Heon et al. (2016) RNA-binding proteins regulate cell respiration and coenzyme Q biosynthesis by post-transcriptional regulation of COQ7. RNA Biol 13:622-34
Kim, Jiyoung; Abdelmohsen, Kotb; Yang, Xiaoling et al. (2016) LncRNA OIP5-AS1/cyrano sponges RNA-binding protein HuR. Nucleic Acids Res 44:2378-92
Yoon, Je-Hyun; Gorospe, Myriam (2016) Identification of mRNA-Interacting Factors by MS2-TRAP (MS2-Tagged RNA Affinity Purification). Methods Mol Biol 1421:15-22
Tsuchiya, Motohiro; Kalurupalle, Swathi; Kumar, Parameet et al. (2016) RPTOR, a novel target of miR-155, elicits a fibrotic phenotype of cystic fibrosis lung epithelium by upregulating CTGF. RNA Biol 13:837-47
Cozzitorto, Joseph A; Jimbo, Masaya; Chand, Saswati et al. (2015) Studying RNA-binding protein interactions with target mRNAs in eukaryotic cells: native ribonucleoprotein immunoprecipitation (RIP) assays. Methods Mol Biol 1262:239-46

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