MicroRNAs as Effectors of Brain Function
2013; Lippincott Williams & Wilkins; Volume: 44; Issue: 6_suppl_1 Linguagem: Inglês
10.1161/strokeaha.113.000985
ISSN1524-4628
Autores Tópico(s)RNA Research and Splicing
ResumoHomeStrokeVol. 44, No. 6_suppl_1MicroRNAs as Effectors of Brain Function Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBMicroRNAs as Effectors of Brain Function Julie Anne Saugstad, PhD Julie Anne SaugstadJulie Anne Saugstad From the Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR. Originally published1 Jun 2013https://doi.org/10.1161/STROKEAHA.113.000985Stroke. 2013;44:S17–S19MicroRNAsMicroRNAs (miRNAs) are a recently discovered family of small, genome-encoded endogenous RNAs that are transcribed but are not translated into proteins. Early studies in Ceanorhabditis elegans revealed that an endogenous small RNA (lin-4) regulated translation of lin-14, a protein required for postembryonic development, through an RNA–RNA interaction.1 Small RNAs were then shown to mediate gene-silencing via a mechanism known as RNA interference (RNAi).2 Fire and Mello2 were awarded the Nobel Prize in Physiology or Medicine in 2006 for the discovery of RNAi. The term miRNA was introduced in a series of back-to-back Science articles in 2001.3–5 MiRNA genes produce primary miRNA transcripts which contain at least one, but possibly more, ≈70 nucleotide hairpin loops. These transcripts are transported into the cytoplasm where they are cleaved by the endonuclease Dicer into an imperfect duplex of 20 to 25 nucleotides. One strand of the duplex is degraded and the other mature miRNA binds to Dicer and forms a complex with argonaute proteins to form RNA-induced silencing complexes.6,7 Studies from several laboratories have revealed that the predominant role of miRNAs in RNA-induced silencing complexes is to regulate post-transcriptional gene expression by translational repression, mRNA cleavage, and mRNA decay initiated by miRNA-guided rapid deadenylation. However, emerging studies support that possible involvement of miRNAs in transcriptional and translational activation. Tremendous progress has been made in unraveling the complexities of miRNAs as meta-controllers of gene expression and their impact on cell development, survival, and function, yet miRNA research is still in its infancy. Given the enormous potential for miRNA studies to translate into novel therapeutic strategies for the diagnosis and treatment of many diseases, the quest to examine all aspects of miRNA functions is fully warranted.MiRNAs and Brain IschemiaMiRNAs serve essential roles in virtually every aspect of brain function, including neurogenesis,8 neural development,9 and cellular responses leading to changes in synaptic plasticity.10 Accordingly, miRNAs are also implicated in neurodegeneration and neurological disorders.11 Further, miRNAs are implicated in responses to hypoxia and ischemia,12 and in ischemic tolerance induced by ischemic preconditioning.13Ischemic tolerance is the response to a short duration of ischemia (preconditioning), which protects cells against a subsequent injurious duration of ischemia.14 Ischemic preconditioning-induced tolerance is known to require new protein synthesis,15 and the signature of tolerance is a transient repression of gene expression.16 We proposed that miRNAs might serve as mediators of new protein synthesis required for tolerance, and thus quantified changes in miRNA expression in preconditioned, ischemic, and tolerant mice induced using varying durations of middle cerebral artery occlusion. We isolated total RNA from the contralateral and ipsilateral cortex of each mouse brain using the mirVana Isolation Kit (Ambion, Austin, TX). The RNAs were labeled, hybridized to the mirVana Probe Set V2 (Ambion) microarray slide that included probes for human, mouse, and rat miRNAs, and microarray slides were scanned on a GenePix 4000B (Axon Instruments, Union City, CA).13 For initial data analysis, an important consideration was to evaluate the consistency of miRNA expression within each group to identify animal-to-animal and diurnal variations in miRNA expression. For each mouse, the change in miRNA expression from 1 animal was compared with the change of the total group, which showed that miRNA expression was consistent within each treatment group and that regulation of miRNAs was not random in individual mice. This type of data analysis is particularly challenging with regard to humans studies where genomics, age, and health will likely impact the consistency of miRNA expression levels in control and patient populations. Our subsequent data analysis revealed that miRNA expression levels were regulated in preconditioned, ischemic, and tolerant mice, and that one prominent predicted target of the miRNAs decreased in preconditioned brain was the global transcriptional regulator, methyl CpG binding protein 2, which had no prior recognized role in preconditioning or tolerance.13 These studies supported our hypothesis that miRNAs were regulated by preconditioning ischemia, and current studies are focused on elucidating the effects of ischemic preconditioning-regulated miRNAs and their role in endogenous neuroprotection.Transient focal ischemia alters miRNA expression in the blood and brain of male rats.17 However, there are differences in responses to focal ischemia in male and female rodent brain; males have greater infarct volumes in response to ischemia than do females.18,19 We recently used real-time quantitative polymerase chain reaction profiling to examine miRNA expression in focal ischemia in male and female C57/BL6 mice. These studies revealed that there is a universal, ischemia-induced miRNA profile, which was equally present in both male and female brains, as well as unique miRNA profiles in either male or female brain (J. Saugstad and S. Murphy, unpublished data, 2013). Current studies are focused on validating these miRNA responses, identifying their cellular targets, and determining their functional relevance to ischemia.Challenges to miRNA StudiesWe and others have found inconsistencies in miRNA expression levels between different array platforms, highlighting the current technical challenges and limitations of miRNA studies. A recent, rigorous study revealed inherent problems within and between the different assays.20 In this study, identical RNA samples assayed on 6 distinct miRNA microarrays obtained from different vendors showed little correlation between the datasets. Only 1 of 6 microarray vendors (Agilent) used probes specifically targeted to the mature miRNA sequence, whereas the others used probes that could detect the mature miRNA sequence but could also detect miRNA sequences in the primary and precursor transcripts. The authors also found inconsistencies between data obtained from the array platforms and NextGen sequencing. This study underscores the complexities and limitations with evolving technologies for miRNA studies and the need to validate changes in miRNA expression using multiple approaches.The translational goal of miRNA expression studies is to identify specific miRNAs and their targets, which may lead to novel therapeutic strategies for diseases. Thus, it is critical to identify and validate miRNA/mRNA target pairs. The complexity of this task is daunting, as a single miRNA can target hundreds of mRNAs, and 1 mRNA can be targeted by hundreds of miRNAs. Computational algorithms and free energy (ΔG) analyses allow for identification of putative miRNA/mRNA targets, but the authenticity of a functional miRNA/mRNA target pair must be validated by additional criteria. As proposed by Kuhn et al,21 (1) miRNA/mRNA target interactions must be verified, (2) the miRNA and predicted mRNA target must be coexpressed, (3) a given miRNA must have a predictable effect on target protein expression, and (4) miRNA-mediated regulation of target gene expression should equate to altered biological function.SummaryIn the relatively short time since their discovery, the miRNAs have been shown to be essential for neuronal development, survival, function, and plasticity. MiRNAs are regulated in response to ischemia and ischemic preconditioning, and male and female mice show both common and unique responses to ischemia, which may contribute to sexually dimorphic responses to ischemia. These findings warrant further studies to examine the role of ischemia-regulated miRNAs on cell death and/or neuroprotection and to identify new targets for alternative strategies for the treatment or prevention of stroke. Given that miRNAs are encoded within the genome, it is conceivable that mutations in miRNA genes and/or their mRNA target sequences, could disrupt normal post-transcriptional gene regulation and lead to disease phenotypes. This may be particularly true for familial diseases, such as stroke, where protein coding gene mutations have not been identified. MiRNAs are also rapidly emerging as biomarkers for diseases, including brain injury, neurodegeneration, and psychiatric disorders.22 Accordingly, there is evidence for altered miRNA expression in peripheral blood isolated from ischemic stroke patients,23,24 suggesting the possibility that blood miRNAs can be used as biomarkers for brain injury, including cerebral ischemia. The first decade of miRNA research has greatly impacted our understanding of the mechanisms underlying normal and altered cellular function, despite technical limitations due to the complexity of miRNAs. In the next decade of miRNA studies, efforts to advance and evolve the tools necessary for analysis and validation of miRNAs, should be fully supported, as these tools will be essential in establishing direct correlations between miRNA-mediated post-transcriptional gene expression and disease, a matter of great importance to human health.AcknowledgmentsI acknowledge my collaborators, Dr Lusardi (Legacy Research Institute, Portland, OR) and Dr Murphy (Oregon Health & Science University) for their contributions and continued enthusiasm in regard to our miRNA studies.Sources of FundingFunding for these studies was supported by grants from the National Institutes of Health R21NS054220 and R01NS064270 (Dr Saugstad).DisclosuresNone.FootnotesCorrespondence to Julie Anne Saugstad, PhD, Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, HRC5N, Portland, OR 97239-3098. E-mail [email protected]References1. Lee RC, Feinbaum RL, Ambros V. The C. elegans heterochronic gene lin-4 encodes small RNAs with antisense complementarity to lin-14.Cell. 1993; 75:843–854.CrossrefMedlineGoogle Scholar2. Fire A, Xu S, Montgomery MK, Kostas SA, Driver SE, Mello CC. Potent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans.Nature. 1998; 391:806–811.CrossrefMedlineGoogle Scholar3. Lagos-Quintana M, Rauhut R, Lendeckel W, Tuschl T. Identification of novel genes coding for small expressed RNAs.Science. 2001; 294:853–858.CrossrefMedlineGoogle Scholar4. Lau NC, Lim LP, Weinstein EG, Bartel DP. An abundant class of tiny RNAs with probable regulatory roles in Caenorhabditis elegans.Science. 2001; 294:858–862.CrossrefMedlineGoogle Scholar5. Lee RC, Ambros V. An extensive class of small RNAs in Caenorhabditis elegans.Science. 2001; 294:862–864.CrossrefMedlineGoogle Scholar6. van den Berg A, Mols J, Han J. RISC-target interaction: cleavage and translational suppression.Biochim Biophys Acta. 2008; 1779:668–677.CrossrefMedlineGoogle Scholar7. Morris KV. RNA-mediated transcriptional gene silencing in human cells.Curr Top Microbiol Immunol. 2008; 320:211–224.MedlineGoogle Scholar8. Li X, Jin P. Roles of small regulatory RNAs in determining neuronal identity.Nat Rev Neurosci. 2010; 11:329–338.CrossrefMedlineGoogle Scholar9. Cochella L, Hobert O. Diverse functions of microRNAs in nervous system development.Curr Top Dev Biol. 2012; 99:115–143.CrossrefMedlineGoogle Scholar10. Goldie BJ, Cairns MJ. Post-transcriptional trafficking and regulation of neuronal gene expression.Mol Neurobiol. 2012; 45:99–108.CrossrefMedlineGoogle Scholar11. Saugstad JA. MicroRNAs as effectors of brain function with roles in ischemia and injury, neuroprotection, and neurodegeneration.J Cereb Blood Flow Metab. 2010; 30:1564–1576.CrossrefMedlineGoogle Scholar12. Fasanaro P, Greco S, Ivan M, Capogrossi MC, Martelli F. microRNA: emerging therapeutic targets in acute ischemic diseases.Pharmacol Ther. 2010; 125:92–104.CrossrefMedlineGoogle Scholar13. Lusardi TA, Farr CD, Faulkner CL, Pignataro G, Yang T, Lan J, et al. Ischemic preconditioning regulates expression of microRNAs and a predicted target, MeCP2, in mouse cortex.J Cereb Blood Flow Metab. 2010; 30:744–756.CrossrefMedlineGoogle Scholar14. Dirnagl U, Becker K, Meisel A. Preconditioning and tolerance against cerebral ischaemia: from experimental strategies to clinical use.Lancet Neurol. 2009; 8:398–412.CrossrefMedlineGoogle Scholar15. Barone FC, White RF, Spera PA, Ellison J, Currie RW, Wang X, et al. Ischemic preconditioning and brain tolerance: temporal histological and functional outcomes, protein synthesis requirement, and interleukin-1 receptor antagonist and early gene expression.Stroke. 1998; 29:1937–50; discussion 1950.LinkGoogle Scholar16. Stenzel-Poore MP, Stevens SL, Xiong Z, Lessov NS, Harrington CA, Mori M, et al. Effect of ischaemic preconditioning on genomic response to cerebral ischaemia: similarity to neuroprotective strategies in hibernation and hypoxia-tolerant states.Lancet. 2003; 362:1028–1037.CrossrefMedlineGoogle Scholar17. Jeyaseelan K, Lim KY, Armugam A. MicroRNA expression in the blood and brain of rats subjected to transient focal ischemia by middle cerebral artery occlusion.Stroke. 2008; 39:959–966.LinkGoogle Scholar18. Alkayed NJ, Harukuni I, Kimes AS, London ED, Traystman RJ, Hurn PD. Gender-linked brain injury in experimental stroke.Stroke. 1998; 29:159–65; discussion 166.LinkGoogle Scholar19. Zhang YQ, Shi J, Rajakumar G, Day AL, Simpkins JW. Effects of gender and estradiol treatment on focal brain ischemia.Brain Res. 1998; 784:321–324.CrossrefMedlineGoogle Scholar20. Git A, Dvinge H, Salmon-Divon M, Osborne M, Kutter C, Hadfield J, et al. Systematic comparison of microarray profiling, real-time PCR, and next-generation sequencing technologies for measuring differential microRNA expression.RNA. 2010; 16:991–1006.CrossrefMedlineGoogle Scholar21. Kuhn DE, Martin MM, Feldman DS, Terry AV, Nuovo GJ, Elton TS. Experimental validation of miRNA targets.Methods. 2008; 44:47–54.CrossrefMedlineGoogle Scholar22. Ceman S, Saugstad J. MicroRNAs: Meta-controllers of gene expression in synaptic activity emerge as genetic and diagnostic markers of human disease.Pharmacol Ther. 2011; 130:26–37.CrossrefMedlineGoogle Scholar23. Liu DZ, Tian Y, Ander BP, Xu H, Stamova BS, Zhan X, et al. Brain and blood microRNA expression profiling of ischemic stroke, intracerebral hemorrhage, and kainate seizures.J Cereb Blood Flow Metab. 2010; 30:92–101.CrossrefMedlineGoogle Scholar24. Tan KS, Armugam A, Sepramaniam S, Lim KY, Setyowati KD, Wang CW, et al. Expression profile of MicroRNAs in young stroke patients.PLoS One. 2009; 4:e7689.CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetailsCited By Banach E, Szczepankiewicz A, Kaczmarek L, Jaworski T and Urban-Ciećko J (2022) Dysregulation of miRNAs Levels in Glycogen Synthase Kinase-3β Overexpressing Mice and the Role of miR-221-5p in Synaptic Function, Neuroscience, 10.1016/j.neuroscience.2022.03.024, 490, (287-295), Online publication date: 1-May-2022. Peedicayil J (2021) Non-coding RNAs and psychiatric disorders Epigenetics in Psychiatry, 10.1016/B978-0-12-823577-5.00003-9, (321-333), . Snijders C, Bassil K and de Nijs L (2018) Methodologies of Neuroepigenetic Research: Background, Challenges and Future Perspectives Neuroepigenetics and Mental Illness, 10.1016/bs.pmbts.2018.04.009, (15-27), . Sun P, Liu D, Jickling G, Sharp F and Yin K (2018) MicroRNA-based therapeutics in central nervous system injuries, Journal of Cerebral Blood Flow & Metabolism, 10.1177/0271678X18773871, 38:7, (1125-1148), Online publication date: 1-Jul-2018. Moon S, Choi D, Oh Y and Cho J (2017) The Effect of Treadmill Exercise on Expression of α-synuclein and miRNA in MPTP Induced-mouse Models of Parkinson's Disease, Exercise Science, 10.15857/ksep.2017.26.2.129, 26:2, (129-138) Li Q, He Q, Baral S, Mao L, Li Y, Jin H, Chen S, An T, Xia Y and Hu B (2016) MicroRNA‐493 regulates angiogenesis in a rat model of ischemic stroke by targeting MIF, The FEBS Journal, 10.1111/febs.13697, 283:9, (1720-1733), Online publication date: 1-May-2016. Martinez B and Peplow P (2016) Blood microRNAs as potential diagnostic and prognostic markers in cerebral ischemic injury, Neural Regeneration Research, 10.4103/1673-5374.191196, 11:9, (1375), . Yuan M, Tang Y, Zhou C, Liu F, Chen L and Yuan H (2015) Elevated plasma CaM expression in patients with acute cerebral infarction predicts poor outcomes and is inversely associated with miR-26b expression, International Journal of Neuroscience, 10.3109/00207454.2015.1020537, 126:5, (408-414), Online publication date: 3-May-2016. Lu Y, Jian M, Ouyang Y and Han R (2015) Changes in Rat Brain MicroRNA Expression Profiles Following Sevoflurane and Propofol Anesthesia, Chinese Medical Journal, 10.4103/0366-6999.157676, 128:11, (1510-1515), Online publication date: 5-Jun-2015. Sun M, Yamashita T, Shang J, Liu N, Deguchi K, Feng J and Abe K (2015) Time-Dependent Profiles of MicroRNA Expression Induced by Ischemic Preconditioning in the Gerbil Hippocampus, Cell Transplantation, 10.3727/096368915X686869, 24:3, (367-376), Online publication date: 1-Mar-2015. Peedicayil J and Beveridge N (2014) Non-Coding RNAs and Psychiatric Disorders Epigenetics in Psychiatry, 10.1016/B978-0-12-417114-5.00012-7, (253-264), . Zhao L, Sun C, Xiong L, Yang Y, Gao Y, Wang L, Zuo H, Xu X, Dong J, Zhou H and Peng R (2014) MicroRNAs: Novel Mechanism Involved in the Pathogenesis of Microwave Exposure on Rats' Hippocampus, Journal of Molecular Neuroscience, 10.1007/s12031-014-0289-4, 53:2, (222-230), Online publication date: 1-Jun-2014. Yan H, Fang M and Liu X (2013) Role of microRNAs in Stroke and Poststroke Depression, The Scientific World Journal, 10.1155/2013/459692, 2013, (1-6), . Pignataro G (2021) Emerging Role of microRNAs in Stroke Protection Elicited by Remote Postconditioning, Frontiers in Neurology, 10.3389/fneur.2021.748709, 12 Ren H, Gu B, Zhang Y, Guo T, Wang Q, Shen Y and Wang J (2021) MicroRNA‑424 alleviates neurocyte injury by targeting PDCD4 in a cellular model of cerebral ischemic stroke, Experimental and Therapeutic Medicine, 10.3892/etm.2021.10888, 22:6 June 2013Vol 44, Issue 6_suppl_1 Advertisement Article InformationMetrics © 2013 American Heart Association, Inc.https://doi.org/10.1161/STROKEAHA.113.000985PMID: 23709715 Manuscript receivedJanuary 29, 2013Manuscript acceptedApril 22, 2013Originally publishedJune 1, 2013 Keywordsmicroarrayischemiapreconditioningpost-transcriptional gene expressionmicroRNAPDF download Advertisement SubjectsGenetics
Referência(s)