Unknown,Transcriptomics,Genomics,Proteomics

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MiRNA Expression in Early Porcine Pregnancy

ABSTRACT: This study examined the expression of pig-specific microRNAs (miRNAs) at gestation day 20 (gd20) of pregnancy in Yorkshire sows. Tissue differences in miRNA expression, and miRNA differences between healthy and arresting embryo attachment sites (i.e., healthy endometrium vs. arresting endometrium; healthy trophoblast vs. arresting trophoblast), were of prime interest. For more information, please refer to the primary research paper. Paired endometrium and trophoblast samples were collected at gestation day 20 from two conceptus attachement sites (1 healthy, 1 arresting) per sow (n=3). Endometrial samples were collected from four non-pregnant sows at mid-estrus.

ORGANISM(S): Sus scrofa

SUBMITTER: Jocelyn Wessels

PROVIDER: E-GEOD-45761 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:A common characteristic of aging is the loss of skeletal muscle (sarcopenia) which can lead to falls and fractures. MicroRNAs (miRNA) are novel post-transcriptional modulators of gene expression with a potential role as a regulator of skeletal muscle mass and function. The purpose of this study was to profile miRNA expression patterns in aging human skeletal muscle using a miRNA array followed by in-depth functional and network analysis. Muscle biopsy samples from 36 men (young: 31Â±2; n=19; older: 73Â±3; n=17) were: 1) analyzed for the expression of miRNAs using a microRNA array 2) validated with Taqman quantitative real-time PCR assays, and 3) identified (and later validated) for potential gene targets using the bioinformatics knowledge base software, Ingenuity Pathways Analysis. We found that 18 miRNAs were differentially expressed in older humans (P<0.05 and >500 expression level). The Let-7 family members, Let-7b and Let-7e, were significantly elevated and further validated in older subjects (P<0.05). Functional and network analysis from Ingenuity determined that gene targets of the Let-7âs were associated with molecular networks involved in cell cycle control such as cellular proliferation and differentiation. We confirmed with real-time PCR that the mRNA expression of the cell cycle regulators, CDK6, CDC25A and CDC34 were downregulated in older subjects compared to the young (P<0.05). These data suggest that aging is characterized by an increased expression of Let-7 family members which may downregulate genes related to cellular proliferation. We propose that the increased Let-7 expression in older human muscle may be an indicator of impaired cell cycle function. We analyzed skeletal muscle biopsy samples from 19 young and 17 older male subjects that have participated in our previous and current research experiments. The subjects were not engaged in any regular exercise training at the time of the enrollment; however they were physically independent and overall healthy. Screening of subjects were performed with clinical history, physical exam, and laboratory tests including complete blood count with differential, liver and kidney function tests, coagulation profile, fasting blood glucose and oral glucose tolerance test, hepatitis B and C screening, HIV test, TSH, urinalysis, and drug screening. All subjects gave informed written consent before participating in the study, which was approved by the Institutional Review Board of the University of Texas Medical Branch (which is in compliance with the Declaration of Helsinki). Once recruited, a dual-energy X-ray absorptiometry (DEXA) scan (Hologic QDR 4500W, Bedford, MA) was performed to measure body composition and lean mass. Study design. All subjects were admitted to the Clinical Research Center the day prior to the experiment, were provided a standardized dinner and were studied following an overnight fast under basal conditions. Subjects were studied during the same time of day to avoid potential circadian changes and refrained from exercise 48h prior to study participation. A muscle biopsy was obtained from the vastus lateralis of the leg. The biopsy was performed using a 5 mm BergstrÃ¶m biopsy needle, under sterile procedure and local anesthesia (1% lidocaine). Muscle biopsy sample was immediately blotted and frozen in liquid nitrogen and stored at -80oC until analysis. The muscle biopsy sample was used for microRNA and gene analysis.

Project description:Background: There is a limited capacity to repair damage in the mammalian heart after birth, which is primarily due to the inability of cardiomyocytes to proliferate after birth. This is in contrast to zebrafish and salamander, in which cardiomyocytes retain the ability to proliferate throughout life and can regenerate their heart after significant damage. Recent studies in zebrafish and rodents implicate microRNAs (miRNAs) in the regulation of genes responsible for cardiac cell cycle progression and regeneration, in particular, miR-133a, the miR-15 family, miR-199a and miR-590. However, the significance of these miRNAs and miRNA in general in the regulation of cardiomyocyte proliferation in large mammals, including humans, where the timing of heart development relative to birth is very different than in rodents, is unclear. To determine the involvement of miRNAs in the down-regulation of cardiomyocyte proliferation occurring before birth in large mammals, we investigated miRNA and target gene expression in sheep hearts before and after birth. The experimental approach included targeted transcriptional profiling of miRNA and target mRNA previously identified in rodent studies as well as genome-wide miRNA profiling using microarrays. Results: The cardiac expression of miR-133a increased and its target gene IGF1R decreased with increasing age, reaching their respective maximum and minimum abundance when the majority of ovine cardiomyocytes were quiescent. The expression of the miR-15 family members was variable with age, however, four of their target genes decreased with age. These latter profiles are inconsistent with the direct involvement of this family of miRNA in cardiomyocyte quiescence in late gestation sheep. The expression patterns of ‘pro-proliferative’ miR-199a and miR-590 were also inconsistent with their involvement in cardiomyocyte quiescence. Consequently, miRNA microarray analysis was undertaken, which identified six discrete clusters of miRNA with characteristic developmental profiles. The functions of predicted target genes for the miRNA in four of the six clusters were enriched for aspects of cell division and regulation of cell proliferation suggesting a potential role of these miRNA in regulating cardiomyocyte proliferation. Conclusion: The results of this study show that the expression of miR-133a and one of its target genes is consistent with it being involved in the suppression of cardiomyocyte proliferation, which occurs across the last third of gestation in sheep. The expression patterns of the miR-15 family, miR-199a and miR-590 were inconsistent with direct involvement in the regulation cardiomyocyte proliferation in sheep, despite studies in rodents demonstrating that their manipulation can influence the degree of cardiomyocyte proliferation. miRNA microarray analysis suggests a coordinated and potentially more complex role of multiple miRNA in the regulation of cardiomyocyte quiescence and highlights significant differences between species that may reflect their substantial differences in the timing of this developmental process. RNA, (2 µg) from three heart samples from each of the 91 d (fetus), 141 d (fetus), 5 d (postnatal) and 173 d (postnatal) groups, was used for analysis according to standard procedures. The experimental design included three biological replicates from each of the four normal developmental ages in sheep and thus a total of 12 samples was analyzed.

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MiRNA Expression in Early Porcine Pregnancy

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