Gestational Stress Disrupts Antepartum Maternal Behaviour Along With miRNA Profiles
Antepartum maternal tail chasing behaviour was scored frame-by-frame from cage-site videotapes. During the observation period, Stress
dams spent significantly less time than Non-stress
dams engaged in tail chasing behaviours, such as horizontal rotations (F(1,13)
5.35, p<0.05; ). Furthermore, gestational stress reduced the number of rotations, although to a non-significant degree (F(1,13)
Gestational stress disrupts antepartum maternal behaviour.
Antepartum stress-induced behavioural alterations were accompanied by altered miRNA expression in the frontal cortex of dams. Since miRNAs in animals primarily inhibit translation of target mRNAs, decreases in miRNA levels should result in increased mRNA translation while increases in miRNA levels result in inhibition of translation (). A total of 342 miRNAs were differentially expressed in response to gestational stress (Stress vs. Non-stress groups). Overall, 195 miRNAs were downregulated and 147 miRNAs were upregulated. Gestational stress downregulated abundance of miR-329, miR-380, miR-20a, and miR-500 (all p≤0.05; ). Stress also led to critical decreases in let-7c, miR-23b, miR-181, and miR186 amounts. Conversely, stress upregulated miR-24-1. The putative gene targets for these miRNAs were related to neuropathologies, neurotransmission, hormonal regulation, neurotrophic factors, stress response, oxidative stress and metabolism (). miR-181 and miR-186 were chosen for verification using qRT-PCR analysis. Downregulation of both miRNAs by gestational stress was confirmed ().
Gestational stress induces differential miRNA expression in frontal cortex. A,
Prenatal Stress Modulates Brain miRNAome and Transcriptome in Newborn Rats
Analysis of the newborn brain miRNAome (Prenatal stress Vs. Non-stress groups ) shows a total of 336 miRNAs differentially expressed in response to prenatal stress, including 131 miRNAs whose abundance was downregulated and 205 miRNAs that were upregulated. The miRNAs differentially regulated by prenatal stress includes miR-23a (up), miR-129-2 (up), miR-361 (down), let-7f (up), miR-17-5p (down), miR-98 (up), miR-425 (down), miR-345-5p (down), miR-9 (up), miR216-5p (up), miR-667 (up), and miR-505 (down) (). Moreover, significant changes in expression due to prenatal stress were found in miR-103 (down), miR-151 (down), and miR-219-2-3p (up). The putative gene targets for these miRNAs includes genes related to miRNA biogenesis, apoptosis, brain pathologies, neurotransmission, neurodevelopment, hormonal regulation, neurotrophic factors, brain angiogenesis, cell signaling, stress response, and metabolism ().
Prenatal stress modulates the brain miRNAome in male newborn offspring. A,
From the miRNAs regulated by prenatal stress (Stress Vs. Non-stress groups), as observed by microarray analyses, the following candidates were selected for verification by qRT-PCR analysis: miR-151, miR-145, miR-425 (all down) and miR-103, miR-323, miR-98 (up) ().
Global gene expression analysis revealed that 39 genes were downregulated by prenatal stress in the brains of newborn rats (more than 2 fold change; Abhd14a, Argbp2, Cd47, RGD1559704, LOC310926, Klf10, Nsmce2, RGD1309216, Gramd1b, Itpr1, Tst, Pfkm, Vps11, Echs1, Zswim5, RGD1309388, Tmem176b, Cib1, Sfxn5, Cln8, Gucy1b3, Flii, Txnl4b, Ldha, RGD1561179, Zfp216, Ptplb, Galntl4, Pdia5, Herc1, RGD1305557, RGD1303003, RGD1305514, Aph1a, Visa, Clpb, RGD1563963, Snx1, Gstm1) and 47 genes were upregulated (more than 2 fold change; P4hb, RGD1560212, RGD735065, LOC498346, Rps3a, LOC497732, Wbp11, Taf9b, RGD1560975, Lpar1, Rnf7, LOC500829, Chp, LOC300760, Pgrmc1, LOC500398, LOC688712, Cd2bp2, RGD1561219, RGD1565840, RGD1560186, LOC497745, LOC497720, LOC500344, Mcts1, RGD1564956, LOC498644, Rala, Sfrs6, Mrlcb, Ptn, Sfrs5, Hdac2, LOC500533, LOC501553, Dazap1, Fem1b, RGD1563431, Cct4, Rbbp7, RGD1308165, Acsl4, Ppp1r14b, LOC498449, Usmg5, RGD1560729). Biological processes affected by these genes include DNA methylation, neurodevelopment, neurotransmission, immune response, growth factor, cell differentiation, neuronal differentiation, axon guidance, apoptosis, mRNA surveillance, translation, brain specific membrane protein, protein processing, stress response, development, cell cycle, detoxification, neuropathology, structural maintenance, transcription, cell signaling and metabolism (). Clustering analysis of gene expression revealed clusters of animals from Prenatal stress and Non-stress groups, except for one animal from the Non-stress group ().
Prenatal stress alters the brain transcriptome in male newborn offspring.
Among genes modulated by prenatal stress with function in metabolic processes, the gene Ptplb was downregulated. Ptplb is a putative target for miR-103, which was upregulated by prenatal stress (). Furthermore, Dazap1 was upregulated by prenatal stress. Dazap1 is a gene related to mRNA surveillance, i.e. regulation of gene expression, which is a putative target for miR-219.