title: Dose-dependent effects of morphine exposure on mRNA and microRNA (miR) expression in hippocampus of stressed neonatal mice.
abstract: Morphine is used to sedate critically ill infants to treat painful or stressful conditions associated with intensive care. Whether neonatal morphine exposure affects microRNA (miR) expression and thereby alters mRNA regulation is unknown. We tested the hypothesis that repeated morphine treatment in stress-exposed neonatal mice alters hippocampal mRNA and miR expression. C57BL/6 male mice were treated from postnatal day (P) 5 to P9 with morphine sulfate at 2 or 5 mg/kg ip twice daily and then exposed to stress consisting of hypoxia (100% N2 1 min and 100% O2 5 min) followed by 2h maternal separation. Control mice were untreated and dam-reared. mRNA and miR expression profiling was performed on hippocampal tissues at P9. Overall, 2 and 5 mg/kg morphine treatment altered expression of a total of 150 transcripts (>1.5 fold change, P<0.05) from which 100 unique mRNAs were recognized (21 genes were up- and 79 genes were down-regulated), and 5 mg/kg morphine affected 63 mRNAs exclusively. The most upregulated mRNAs were fidgetin, arginine vasopressin, and resistin-like alpha, and the most down-regulated were defensin beta 11, aquaporin 1, calmodulin-like 4, chloride intracellular channel 6, and claudin 2. Gene Set Enrichment Analysis revealed that morphine treatment affected pathways related to cell cycle, membrane function, signaling, metabolism, cell death, transcriptional regulation, and immune response. Morphine decreased expression of miR-204-5p, miR-455-3p, miR-448-5p, and miR-574-3p. Nine morphine-responsive mRNAs that are involved in neurodevelopment, neurotransmission, and inflammation are predicted targets of the aforementioned differentially expressed miRs. These data establish that morphine produces dose-dependent changes in both hippocampal mRNA and miR expression in stressed neonatal mice. If permanent, morphine-mediated neuroepigenetic effects may affect long-term hippocampal function, and this provides a mechanism for the neonatal morphine-related impairment of adult learning.
authors.affiliation: Department of Pediatrics, Division of Neonatology, University of Washington, Seattle, Washington, United States of America.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: McAdams
authors.affiliation: Department of Pediatrics, Division of Neonatology, University of Washington, Seattle, Washington, United States of America.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: McPherson
authors.affiliation: Dept of Environmental & Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Beyer
authors.affiliation: Dept of Environmental & Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America.
authors.forename: Theo K
authors.initials: TK
authors.lastname: Bammler
authors.affiliation: Dept of Environmental & Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America.
authors.forename: Frederico M
authors.initials: FM
authors.lastname: Farin
authors.affiliation: Department of Pediatrics, Division of Neonatology, University of Washington, Seattle, Washington, United States of America.
authors.forename: Sandra E
authors.initials: SE
authors.lastname: Juul
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D004305:Dose-Response Relationship, Drug; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D035683:MicroRNAs / Q000235:genetics*; D009020:Morphine / Q000008:administration & dosage* / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics*; D013312:Stress, Physiological / Q000187:drug effects; D013315:Stress, Psychological / Q000235:genetics / Q000473:pathology
chemical_list: D000701:Analgesics, Opioid; D035683:MicroRNAs; D012333:RNA, Messenger; D009020:Morphine
references.citation: Proc Natl Acad Sci U S A. 2005 Oct 25;102(43):15545-50
references.pmid: 16199517
references.citation: J Perinatol. 2007 May;27 Suppl 1:S4-S11
references.pmid: 17453028
references.citation: Pediatr Res. 2011 Apr;69(4):285-92
references.pmid: 21178816
references.citation: Hippocampus. 2003;13(4):461-71
references.pmid: 12836915
references.citation: Nat Rev Genet. 2006 Jan;7(1):55-65
references.pmid: 16369572
references.citation: ASN Neuro. 2012;4(5). pii: e00096. doi: 10.1042/AN20110020
references.pmid: 22867428
references.citation: Front Genet. 2012 Nov 09;3:223
references.pmid: 23162566
references.citation: Metab Brain Dis. 2013 Sep;28(3):429-38
references.pmid: 23378107
references.citation: Neuroscience. 2014 Mar 7;261:173-83
references.pmid: 24384227
references.citation: Nat Cell Biol. 2011 Mar;13(3):254-62
references.pmid: 21336305
references.citation: J Neuroimmune Pharmacol. 2011 Dec;6(4):442-65
references.pmid: 21789507
references.citation: Synapse. 2013 Nov;67(11):757-72
references.pmid: 23720407
references.citation: Mol Pharmacol. 2010 Nov;78(5):935-42
references.pmid: 20716624
references.citation: Cell Mol Life Sci. 2012 Jan;69(1):89-102
references.pmid: 21833581
references.citation: Future Med Chem. 2012 Sep;4(13):1671-9
references.pmid: 22924505
references.citation: Mol Pharmacol. 2010 Jan;77(1):102-9
references.pmid: 19854889
references.citation: Neuron. 2012 Aug 9;75(3):363-79
references.pmid: 22884321
references.citation: Int J Biochem Cell Biol. 2007;39(3):490-6
references.pmid: 17194618
references.citation: J Immunol. 2001 Jan 15;166(2):918-25
references.pmid: 11145668
references.citation: Proc Natl Acad Sci U S A. 2004 Mar 16;101(11):3833-8
references.pmid: 15007177
references.citation: Hum Mutat. 2008 Jul;29(7):966-74
references.pmid: 18428203
references.citation: Mol Psychiatry. 2014 Jul;19(7):848-52
references.pmid: 23917947
references.citation: Proc Natl Acad Sci U S A. 1980 Oct;77(10):6239-43
references.pmid: 6255483
references.citation: Surgery. 2001 Aug;130(2):304-9
references.pmid: 11490364
references.citation: Front Genet. 2012 Jun 21;3:110
references.pmid: 22737161
references.citation: Nat Med. 2013 Oct;19(10):1227-31
references.pmid: 24100992
references.citation: J Cell Biochem. 2010 Jul 1;110(4):834-45
references.pmid: 20564181
references.citation: Curr Biol. 2013 May 20;23(10):850-61
references.pmid: 23602477
references.citation: Neonatology. 2009;96(4):235-43
references.pmid: 19478529
references.citation: Stat Appl Genet Mol Biol. 2009;8:Article34
references.pmid: 19645689
references.citation: Eur J Hum Genet. 2014 Mar;22(3):363-8
references.pmid: 23756445
references.citation: Ann Neurol. 2005 Dec;58(6):821-8
references.pmid: 16250014
references.citation: Folia Neuropathol. 2011;49(4):328-34
references.pmid: 22212923
references.citation: J Perinatol. 2013 May;33(5):374-82
references.pmid: 23047422
references.citation: J Anesth. 2013 Feb;27(1):80-7
references.pmid: 22932814
references.citation: J Leukoc Biol. 2000 Nov;68(5):723-8
references.pmid: 11073113
references.citation: Genome Biol. 2004;5(10):R80
references.pmid: 15461798
references.citation: Genome Res. 2009 Jan;19(1):92-105
references.pmid: 18955434
references.citation: Early Hum Dev. 2011 Mar;87 Suppl 1:S19-22
references.pmid: 21276670
references.citation: Mol Med. 2006 Nov-Dec;12(11-12):284-90
references.pmid: 17380193
references.citation: Blood. 2010 Aug 5;116(5):731-9
references.pmid: 20445021
references.citation: Stat Appl Genet Mol Biol. 2004;3:Article3
references.pmid: 16646809
references.citation: Neuroscientist. 2012 Apr;18(2):114-8
references.pmid: 21555783
references.citation: Behav Brain Res. 2012 Feb 1;227(1):7-11
references.pmid: 22061798
references.citation: Cell. 2004 Jan 23;116(2):281-97
references.pmid: 14744438
references.citation: Genet Epidemiol. 2002 Jun;23(1):70-86
references.pmid: 12112249
references.citation: Prog Mol Biol Transl Sci. 2011;102:47-100
references.pmid: 21846569
references.citation: ScientificWorldJournal. 2012;2012:905785
references.pmid: 22606066
references.citation: Mol Cell Neurosci. 2009 Nov;42(3):219-25
references.pmid: 19607921
references.citation: Dev Biol. 2014 Mar 15;387(2):203-13
references.pmid: 24457099
references.citation: J Genet Genomics. 2013 Feb 20;40(2):61-6
references.pmid: 23439404
references.citation: Pharmacol Rep. 2012;64(5):1200-15
references.pmid: 23238476
references.citation: Nat Cell Biol. 2010 Oct;12(10):999-1006
references.pmid: 20835244
references.citation: Mol Cell Proteomics. 2012 Sep;11(9):605-18
references.pmid: 22580588
references.citation: Nature. 2006 Jan 19;439(7074):283-9
references.pmid: 16421561
references.citation: J Neurosci. 2010 Jul 28;30(30):10251-8
references.pmid: 20668208
references.citation: J Neuroimmunol. 2004 Feb;147(1-2):78-81
references.pmid: 14741432
references.citation: Front Genet. 2012 Nov 26;3:241
references.pmid: 23233859
references.citation: J Neuroimmunol. 2013 Dec 15;265(1-2):43-50
references.pmid: 24090653
references.citation: Front Endocrinol (Lausanne). 2013 Sep 18;4:124
references.pmid: 24065953
references.citation: Front Neurosci. 2012 Feb 06;6:13
references.pmid: 22347159
references.citation: Proc Natl Acad Sci U S A. 2001 Apr 24;98(9):5116-21
references.pmid: 11309499
references.citation: Mol Neurobiol. 2011 Apr;43(2):107-13
references.pmid: 21086067
references.citation: FASEB J. 2013 Feb;27(2):522-35
references.pmid: 23085997
references.citation: Neonatology. 2007;92(1):33-41
references.pmid: 17596735
references.citation: Proc Natl Acad Sci U S A. 1996 Nov 26;93(24):13748-53
references.pmid: 8943006
references.citation: Proc Natl Acad Sci U S A. 2000 Jun 20;97(13):7579-84
references.pmid: 10840056
references.citation: Neuroscience. 2008 Apr 9;152(4):924-41
references.pmid: 18343589
references.citation: Neurosci Lett. 2013 Jun 17;545:17-22
references.pmid: 23603260
references.citation: Addict Biol. 2013 May;18(3):480-95
references.pmid: 22804800
references.citation: Eur J Neurosci. 2005 Jan;21(2):493-500
references.pmid: 15673448
references.citation: Neonatology. 2009;95(3):230-9
references.pmid: 18953183
references.citation: Diabetes. 2011 Jul;60(7):1907-16
references.pmid: 21593200
references.citation: Pediatr Res. 2009 Sep;66(3):278-82
references.pmid: 19531978