Project description:Critically ill preterm infants experience multiple stressors while hospitalized. Morphine is commonly prescribed to ameliorate their pain and stress. We hypothesized that neonatal stress will have a dose-dependent effect on hippocampal gene expression, and these effects will be altered by morphine treatment. Male C57BL/6 mice were exposed to 5 treatment conditions between postnatal day 5 and 9: 1) Control, 2) mild stress + saline, 3) mild stress + morphine, 4) severe stress + saline and 5) severe stress + morphine. Hippocampal RNA was extracted and analyzed using Affymetrix Mouse Gene 1.0 ST Arrays. Single gene analysis and gene set analysis were used to compare groups with validation by qPCR. Stress resulted in enrichment of genes sets related to fear response, oxygen carrying capacity and NMDA receptor synthesis. Morphine downregulated gene sets related to immune function. Stress plus morphine resulted in enrichment of mitochondrial electron transport gene sets, and down-regulation of gene sets related to brain development and growth. We conclude that neonatal stress alone influences hippocampal gene expression, morphine alters a subset of stress-related changes in gene expression and influences other gene sets. Stress plus morphine show interaction effects not present with either stimulus alone. These changes may alter neurodevelopment. Male mice were exposed to 5 treatment conditions between postnatal day (P)5 and P9 (n=3/group), with birth recorded as P1. Litters were culled to n=7 maximum per dam. Groups included: 1) Untreated controls (CC), 2) mild stress + saline (MSS), 3) mild stress + morphine (MSM), 4) severe stress + saline (SSS) and 5) severe stress + morphine (SSM).
Project description:Critically ill preterm infants experience multiple stressors while hospitalized. Morphine is commonly prescribed to ameliorate their pain and stress. We hypothesized that neonatal stress will have a dose-dependent effect on hippocampal gene expression, and these effects will be altered by morphine treatment. Male C57BL/6 mice were exposed to 5 treatment conditions between postnatal day 5 and 9: 1) Control, 2) mild stress + saline, 3) mild stress + morphine, 4) severe stress + saline and 5) severe stress + morphine. Hippocampal RNA was extracted and analyzed using Affymetrix Mouse Gene 1.0 ST Arrays. Single gene analysis and gene set analysis were used to compare groups with validation by qPCR. Stress resulted in enrichment of genes sets related to fear response, oxygen carrying capacity and NMDA receptor synthesis. Morphine downregulated gene sets related to immune function. Stress plus morphine resulted in enrichment of mitochondrial electron transport gene sets, and down-regulation of gene sets related to brain development and growth. We conclude that neonatal stress alone influences hippocampal gene expression, morphine alters a subset of stress-related changes in gene expression and influences other gene sets. Stress plus morphine show interaction effects not present with either stimulus alone. These changes may alter neurodevelopment.
Project description: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 gene expression. C57BL/6 male mice were treated from postnatal day (P) 5 to P9 with morphine at 2 or 5 mg/kg ip bid (MS5) 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 microRNA expression profiling was performed on hippocampal tissues at P9. Overall, MS2 and MS5 morphine treatment altered expression of a total of 150 mRNAs (>1.5 fold change, P<0.05; 36 up, 114 down), and MS5 affected 63 mRNAs. 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. MS5 decreased expression of miR-204-5p, miR-455-3p, miR-448-3p, and miR-574-3p.Nine morphine-responsive mRNAs that are involved in neurodevelopment, neurotransmission, and inflammation are predicted targets of the aforementioned differentially expressed microRNAs These data establish that morphine produces dose-dependent changes in both hippocampal mRNA and miR gene 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.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Transcription profiling of murine fetal hearts treated with different doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin to study the effects of TCDD on gene expression during murine cardiovascular development
Project description:Translational research is commonly performed in the C57B6/J mouse strain, chosen for its genetic homogeneity and phenotypic uniformity. Here, we evaluate the suitability of the white-footed deer mouse (Peromyscus leucopus) as a model organism for aging research, offering a comparative analysis against C57B6/J and diversity outbred (DO) Mus musculus strains. Our study includes comparisons of body composition, skeletal muscle function, and cardiovascular parameters, shedding light on potential applications and limitations of P. leucopus in aging studies. Notably, P. leucopus exhibits distinct body composition characteristics, emphasizing reduced muscle force exertion and a unique metabolism, particularly in fat mass. Cardiovascular assessments showed changes in arterial stiffness, challenging conventional assumptions and highlighting the need for a nuanced interpretation of aging-related phenotypes. Our study also highlights inherent challenges associated with maintaining and phenotyping P. leucopus cohorts. Behavioral considerations, including anxiety-induced responses during handling and phenotyping assessment, pose obstacles in acquiring meaningful data. Moreover, the unique anatomy of P. leucopus necessitates careful adaptation of protocols designed for Mus musculus. While showcasing potential benefits, further extensive analyses across broader age ranges and larger cohorts are necessary to establish the reliability of P. leucopus as a robust and translatable model for aging studies.