Dataset Information

Alterations in hepatic miRNA expression during negative energy balance in postpartum dairy cattle.

ABSTRACT: BACKGROUND:Negative energy balance (NEB), an altered metabolic state, occurs in early postpartum dairy cattle when energy demands to support lactation exceed energy intake. During NEB the liver undergoes oxidative stress and increased breakdown of fatty acids accompanied by changes in gene expression. It is now known that micro RNAs (miRNA) can have a role in mediating such alterations in gene expression through repression or degradation of target mRNAs. miRNA expression is known to be altered by metabolism and environmental factors and miRNAs are implicated in expression modulation of metabolism related genes. RESULTS:miRNA expression was profiled in the liver of moderate yielding dairy cattle under severe NEB (SNEB) and mild NEB (MNEB) using the Affymetrix Gene Chip miRNA_2.0 array with 679 probe sets for Bos-taurus miRNAs. Ten miRNAs were found to be differentially expressed using the 'samr' statistical package (delta = 0.6) at a q-value FDR of < 12%. Five miRNAs including miR-17-5p, miR-31, miR-140, miR-1281 and miR-2885 were validated using RT-qPCR, to be up-regulated under SNEB. Liver diseases associated with these miRNAs include non-alcoholic fatty liver (NAFLD) and hepatocellular carcinoma (HCC). miR-140 and miR-17-5p are known to show differential expression under oxidative stress. A total of 32 down-regulated putative target genes were also identified among 418 differentially expressed hepatic genes previously reported for the same animal model. Among these, GPR37 (G protein-coupled receptor 37), HEYL (hairy/enhancer-of-split related with YRPW motif-like), DNJA1, CD14 (Cluster of differentiation 14) and GNS (glucosamine (N-acetyl)-6-sulfatase) are known to be associated with hepatic metabolic disorders. In addition miR-140 and miR-2885 have binding sites on the most down-regulated of these genes, FADS2 (Fatty acid desaturase 2) which encodes an enzyme critical in lipid biosynthesis. Furthermore, HNF3-gamma (Hepatocyte nuclear factor 3-gamma), a hepatic transcription factor (TF) that is involved in IGF-1 expression regulation and maintenance of glucose homeostasis is a putative target of miR-31. CONCLUSIONS:This study shows that SNEB affects liver miRNA expression and these miRNAs have putative targets in hepatic genes down-regulated under this condition. This study highlights the potential role of miRNAs in transcription regulation of hepatic gene expression during SNEB in dairy cattle.

SUBMITTER: Fatima A

PROVIDER: S-EPMC3902422 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature

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Alterations in hepatic miRNA expression during negative energy balance in postpartum dairy cattle.

Fatima Attia A Waters Sinead S O'Boyle Padraig P Seoighe Cathal C Morris Dermot G DG

BMC genomics 20140115

<h4>Background</h4>Negative energy balance (NEB), an altered metabolic state, occurs in early postpartum dairy cattle when energy demands to support lactation exceed energy intake. During NEB the liver undergoes oxidative stress and increased breakdown of fatty acids accompanied by changes in gene expression. It is now known that micro RNAs (miRNA) can have a role in mediating such alterations in gene expression through repression or degradation of target mRNAs. miRNA expression is known to be a ...[more]

PMID: 24428929

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Project description:In high yielding dairy cows the liver undergoes extensive physiological and biochemical changes during the early postpartum period in an effort to re-establish metabolic homeostasis and to counteract the adverse effects of negative energy balance (NEB). These adaptations are likely to be mediated by significant alterations in hepatic gene expression. To gain new insights into these events an EB model was created using differential feeding and milking regimes to produce two groups of cows with either a mild (MNEB) (n=5) or severe NEB (SNEB) (n=6) status. Cows were slaughtered and liver tissues collected on days 6-7 of the first follicular wave postpartum. Using an AffymetrixM-BM-. 23k oligonucleotide bovine array to determine global gene expression in hepatic tissue of these cows, a total of 416 genes (189 up- and 227 down-regulated) were found to be altered by SNEB. Network analysis using Ingenuity Pathway Analysis revealed that SNEB was associated with widespread changes in gene expression classified into 36 gene networks including those associated with lipid metabolism, connective tissue development and function, cell signalling, cell cycle and metabolic diseases. Severe NEB cows displayed reduced expression of transcription activators and signal transducers that regulate the expression of genes and gene networks associated with cell signalling and tissue repair. These alterations are linked with increased expression of abnormal cell cycle and cellular proliferation associated pathways. This study provides new information and insights on the effect of SNEB on gene expression in high yielding Holstein Friesian dairy cows in the early postpartum period. Multiparous Holstein-Friesian cows (n=24) were blocked 2 weeks prior to expected calving date according to parity, body condition score, and previous lactation yield (average lactation 6477M-BM-1354kg) and randomly allocated to mild (MNEB; n=12) or severe (SNEB; n=12) NEB groups. MNEB cows were fed ad lib grass silage and 8 kg day-1 concentrates and milked once daily; SNEB cows were fed 25 kg day-1 silage and 4kg day-1 concentrate and milked three times daily. Measurements of body condition score and EB were used to select cows which showed extremes in EB from each group (MNEB, n=5; SNEB, n=6). Cows were slaughtered on days 6-7 of the first follicular wave after calving (mean number of days post-partum: MNEB mean 13.6 M-BM-1 0.75, range 11M-bM-^@M-^S15; SNEB mean 14.3 M-BM-1 0.56, range 13M-bM-^@M-^S16), based on daily transrectal ultrasonography.The entire liver was removed within 15 to 30 min after slaughter and weighed. Samples weighing approximately 1 g were dissected, rinsed in RNase free phosphate buffer, snap frozen in liquid nitrogen and stored at -80M-BM-:C.

Project description:BACKGROUND: Negative energy balance (NEB) is an altered metabolic state in high yielding cows that occurs during the first few weeks postpartum when energy demands for lactation and maintenance exceed the energy supply from dietary intake. NEB can, in turn, lead to metabolic disorders and to reduced fertility. Alterations in the expression of more than 700 hepatic genes have previously been reported in a study of NEB in postpartum dairy cows. miRNAs (microRNA) are known to mediate many alterations in gene expression post transcriptionally. To study the hepatic miRNA content of postpartum dairy cows, including their overall abundance and differential expression, in mild NEB (MNEB) and severe NEB (SNEB), short read RNA sequencing was carried out. To identify putative targets of differentially expressed miRNAs among differentially expressed hepatic genes reported previously in dairy cows in SNEB computational target identification was employed. RESULTS: Our results indicate that the dairy cow liver expresses 53 miRNAs at a lower threshold of 10 reads per million. Of these, 10 miRNAs accounted for greater than 95% of the miRNAome (miRNA content). Of the highly expressed miRNAs, miR-122 constitutes 75% followed by miR-192 and miR-3596. Five out of thirteen let-7 miRNA family members are also among the highly expressed miRNAs. miR-143, down-regulated in SNEB, was found to have 4 putative up-regulated gene targets associated with SNEB including LRP2 (low density lipoprotein receptor-related protein 2), involved in lipid metabolism and up-regulated in SNEB. CONCLUSIONS: This is the first liver miRNA-seq profiling study of moderate yielding dairy cows in the early postpartum period. Tissue specific miR-122 and liver enriched miR-192 are two of the most abundant miRNAs in the postpartum dairy cow liver. miR-143 is significantly down-regulated in SNEB and putative targets of miRNA-143 which are up-regulated in SNEB, include a gene involved in lipid metabolism.

Project description:Increased energy demands to support lactation, coupled with lowered feed intake capacity results in negative energy balance (NEB) and is typically characterized by extensive mobilization of body energy reserves in the early postpartum dairy cow. The catabolism of stored lipid leads to an increase in the systemic concentrations of nonesterified fatty acids (NEFA) and -hydroxy butyrate (BHB). Oxidation of NEFA in the liver result in the increased production of reactive oxygen species and the onset of oxidative stress and can lead to disruption of normal metabolism and physiology. The immune system is depressed in the peripartum period and early lactation and dairy cows are therefore more vulnerable to bacterial infections causing mastitis and or endometritis at this time. A bovine Affymetrix oligonucleotide array was used to determine global gene expression in the spleen of dairy cows in the early postpartum period. Spleen tissue was removed post mortem from five severe NEB (SNEB) and five medium NEB (MNEB) cows 15 days postpartum.SNEB increased systemic concentrations of NEFA and BHB, and white blood cell and lymphocyte numbers were decreased in SNEB animals. A total of 545 genes were altered by SNEB. Network analysis using Ingenuity Pathway Analysis revealed that SNEB was associated with NRF2-mediated oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, natural killer cell signaling, p53 signaling, downregulation of IL-15, BCL-2, and IFN- ; upregulation of BAX and CHOP and increased apoptosis with a potential negative impact on innate and adaptive immunity. Multiparous Holstein-Friesian cows (n=24) were blocked 2 weeks prior to expected calving date according to parity, body condition score, and previous lactation yield (average lactation 6477M-BM-1354kg) and randomly allocated to mild (MNEB; n=12) or severe (SNEB; n=12) NEB groups. MNEB cows were fed ad lib grass silage and 8 kg day-1 concentrates and milked once daily; SNEB cows were fed 25 kg day-1 silage and 4kg day-1 concentrate and milked three times daily. Measurements of body condition score and EB were used to select cows which showed extremes in EB from each group (MNEB, n=5; SNEB, n=5). Cows were slaughtered on days 6-7 of the first follicular wave after calving (mean number of days post-partum: MNEB mean 13.6 M-BM-1 0.75, range 11M-bM-^@M-^S15; SNEB mean 14.3 M-BM-1 0.56, range 13M-bM-^@M-^S16), based on daily transrectal ultrasonography.At slaughter the entire spleen was removed and weighed, and samples weighing 1 g were dissected, rinsed in RNase-free phosphate buffer, snap frozen in liquid nitrogen, stored for 4 h in dry ice, and subsequently stored at 80M-BM-0C.

Dataset Information

Alterations in hepatic miRNA expression during negative energy balance in postpartum dairy cattle.

Publications

Alterations in hepatic miRNA expression during negative energy balance in postpartum dairy cattle.

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