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Liver transcriptome modifications by nutrient restriction in early lactation Holstein cows challenged with intramammary lipopolysaccharide

ABSTRACT: The objective was to evaluate the effects of nutrient restriction on the liver transcriptomic response after 24 h challenge to intramammary lipopolysaccharide (LPS) in early lactation cows. At 24 ± 3 days of lactation, multiparous cows were fed either an ad libitum lactation diet (CON, n = 6), or a ration diluted with barley straw (48% DM) for 4 days (RES, n = 6). On day 3, one healthy rear mammary quarter from each cow was infused with 50 µg of LPS. Blood and liver biopsies were collected on day 4, corresponding to 24 h after LPS challenge. The liver transcriptome was analyzed using 44K bovine microarrays (Agilent Technologies). Blood and transcriptomic data were analyzed using SAS mixed models and GeneSpring (moderate t-test with Westfall-Young correction, P < 0.05), respectively, and data mining was performed using Panther and Pathway Studio software. The energy balance was no different before the diet change. By experimental design, energy intake was 41 and 97 ± 15 % of NEL requirements in RES and CON, respectively. Plasma NEFA and BHBA were higher, and glucose was lower in RES than in CON, which is consistent with a 4-day nutrient deficit in RES. Seventy seven differentially expressed genes (DEGs) between CON and RES were identified, with 29 genes downregulated and 48 upregulated in RES. Genes involved in fatty acid synthesis (ACAT2, FASN, SCD), lactate metabolism (LDHC), and cortisol binding (SERPINA6) were downregulated in RES, while those involved in fatty acid oxidation, detoxification, cholesterol synthesis, lipoprotein lipid secretion, and gluconeogenesis (ACADVL, CPT1A, CPT1B, ANGPTL4, CYP4A11, HMGCSA, APOA1, APOA4, GK, PC and PCK2) were upregulated in RES. Overall, DEGs were in agreement with the negative energy balance and plasma metabolite profile, and reflect a state of intense lipomobilization, glucose deficit and ketogenesis in RES. Preliminary results suggest that nutrient restriction did not alter hepatic expression of genes directly involved in immune function 24 h after an intramammary LPS challenge.

ORGANISM(S): Bos taurus

PROVIDER: GSE261541 | GEO | 2024/09/06

REPOSITORIES: GEO

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Project description:The objective was to evaluate the effect of nutrient restriction and intramammary lipopolysaccharide (LPS) challenge on mammary gland (MG) gene expression in early lactation cows. At 24 ± 3 d in milk, multiparous cows were either allowed to continue ad libitum intake of a lactation diet (CON, n = 6), or the ration was diluted with barley straw (48% DM) for 4 d (RES, n = 6). On d 3, one healthy rear mammary quarter was infused with 50 µg of LPS. Mammary biopsies were performed 24 h after LPS challenge. RNA and proteins analyzed using bovine 44K microarrays (Agilent Technologies) and micro-LC-MS/MS, respectively. Transcriptomic data were analyzed using GeneSpring (moderated-t-test with Westfall-Young correction, P < 0.05). Proteins were analyzed with Progenesis LC-MS software v4.1 (Nonlinear Dynamics). Production and energy balance did not differ prior to diet change. Negative energy balance was aggravated in RES (41 vs 97 ± 15 % of requirements, mean ± SD; P < 0.001). A total of 87 differentially expressed genes (DEG) were highlighted through the comparison of RES vs CON group. Among the 33 DEG identified in the transcriptomic analyses, 11 and 22 were down- and upregulated by restriction, respectively. Among the upregulated DEG, there were PDK4 and CPT1A which are involved in the regulation of fatty acid, ketone, and glucose metabolism. CPT1A is the key enzyme in the carnitine dependent fatty acid transport, promoting fatty acid oxidation. Genes involved in immune response such as PGLYRP3 and TRIB2 were upregulated, suggesting a higher inflammatory response in RES than CON. Proteomic analysis identified 54 proteins with 14 up- and 40 downregulated in RES cows. Upregulated proteins were mostly involved in gene expression mechanisms such as translation, RNA splicing and cellular protein modification. The downregulated proteins (e.g., EIF3H, RS27A, RS15) take part in protein metabolism. This is coherent with transcriptomic results, namely the downregulation of RPL 37A, a component of ribosomal complex, which catalyzes protein synthesis and may partially explain the lower milk protein yield in RES (834 vs 1163 g/d; P = 0.02). Proteins involved in antigen processing and presentation were downregulated in RES compared to CON, suggesting an impaired ability to counteract inflammation in RES MG. Preliminary transcriptomics and proteomics analyses show that undernutrition may influence the MG response to inflammation at each level of gene expression.

Project description:Our objectives were to compare gene expression profiles in neutrophils (PMN) during a Streptococcus uberis mastitis challenge between lactating cows subjected to feed restriction to induce negative energy balance (NEB; n = 5) and cows fed ad libitum to maintain positive energy balance (PEB; n = 5). The NEB cows were feed-restricted to 60% of calculated net energy for lactation requirements for 7 d, whereas PEB cows were fed the same diet for ad libitum intake. After 5 d of feed restriction, one rear mammary quarter of each cow was inoculated with 5,000 cfu of Streptococcus uberis (strain O140J). Blood PMN were isolated at 24 h post-inoculation from all cows for RNA extraction and microarray analysis. NEB resulted in 94 differentially expressed genes compared with PEB. Of these, 51 genes were down-regulated, including genes involved with antigen presentation (HLADRA and HLAA), respiratory burst (SOD1), and the pro-inflammatory response (TNFA and IRAK-1). The most affected genes up-regulated by NEB (n = 43) included IL1R2 and IL6, toll-like receptors (TLR2 and TLR4), and THY1. Network analysis by Ingenuity Pathway Analysis Â® revealed that TNFA was associated with the expression of numerous differentially expressed genes involved with immune response in NEB cows compared with PEB cows. Energy balance alters PMN expression of several genes involved with immune response, which provides new information on transcriptomic mechanisms associated with post-partal NEB and immune response during early lactation. Briefly, 10 multiparous Holstein cows in PEB and past peak lactation were used for this study. The NEB cows were feed-restricted to 60% of calculated NEL requirements for 7 d, whereas PEB cows were fed the same diet for ad libitum intake. After 5 d of feed restriction, one rear mammary quarter of each cow was inoculated with 5,000 cfu of Streptococcus uberis (strain O140J). Blood PMN were isolated at 24 h post-inoculation from all cows. A 13,257-oligonucleotide (70-mers) array was used for transcript profiling. Cy3- and Cy5 labelled cDNA from PMN and a reference standard were used for hybridizations. All samples were hybridized to duplicate slides with reverse labeling (20 microarrays total).

Project description:The study investigated the acute and simultaneous response of the mammary and liver transcriptome to an intra-mammary lipopolysaccharide (LPS) challenge in early-lactating cows, and its consequences on metabolic biomarkers and liver composition. At 7 days of lactation, 7 cows served as controls (CTR) and 7 cows (LPS) received an intra-mammary E. coli LPS challenge. The mammary and liver tissues were sampled at 2.5 h from challenge for transcriptomic profiling. Liver composition was evaluated at 2.5 h and 7 d after challenge and blood biomarkers were analized at -2, 3, 7 and 14 d from challenge. In mammary tissue, the LPS challenge resulted in 189 differentially expressed gene (DEG), with 20 downregulated and 169 upregulated, while in the liver were found 107 DEG with 42 downregulated and 65 upregulated in LPS vs CTR. In the udder, the Dynamic Impact Approach (DIA) highlighted the activation of NOD-like receptor signaling, Toll-like receptor signaling, RIG-I-like receptor signaling and Apoptosis pathways, while in the liver were inhibited the Fatty acid elongation in mitochondria and activated the p53 signaling pathway. The LPS induced the alteration of liver lipid metabolism (rise of total lipid and triglyceride concentration), a systemic inflammation (rise of blood ceruloplasmin and bilirubin) and an increase of body fat mobilization. In cows subjected to intra-mammary LPS, the mammary gland responds activating mechanisms of pathogen recognition. In the liver the response likely depends by mediators coming from udder and affects the liver functionality and mainly the fatty acid metabolism. Fourteen Holstein cows entering their second or greater lactation were used. Cows were housed in a ventilated tie-stall barn and were fed a common lactation diet (Net energy of lactation = 1.69 Mcal/kg DM) as a total mixed ration once daily (0600 h) and milked twice daily (0400 and 1600 h). A bovine oligonucleotide (70-mers) microarray with >13,000 annotated sequences developed at the University of Illinois, was used for transcript profiling. Details on the development, annotation, and use of this microarray have been reported previously by Loor et al., 2007 (http://physiolgenomics.physiology.org/content/32/1/105.abstract). Methods for microarray hybridization and scanning were as reported by Loor et al. (2007). Briefly, slides were hydrated, dried, and placed in a UV Stratalinker 1800 (Stratagene, La Joya, CA) for ~5 min. Slides were washed with 0.2% SDS solution, rinsed with MilliQ (Millipore) H2O, and placed in warm prehybridization soln for 45 min at 42 C. The same amount of Cy3- or Cy5-labelled cDNA from mammary or liver and a reference standard RNA pool (made of different bovine tissues) were co-hybridized using a dye-swap design (i.e., two microarrays per sample). Slides were incubated for 48 h at 45 C prior to scanning. Criteria for evaluation of slide quality included: identification of number of spots with a minimum median signal intensity of 3 SD above background; keeping slides with a minimum of 20,000 spots with minimum median signal intensity of 3 SD above background in both Cy3 and Cy5 channels; and keeping slides with a minimum mean intensity of 400 relative fluorescent units in both Cy3 and Cy5 channels across the entire slide. Data from a total of 112 microarrays were normalized for dye and microarray effects (i.e., Lowess normalization and microarray centering) and used for statistical analysis. Data were analyzed using the Proc MIXED procedure of SAS (SAS, SAS Inst. Inc., Cary, NC). Fixed effects were treatment (LPS challenge, control (no infsuion)) and dye. Random effects included cow and microarray. Raw P values were adjusted using Benjamini and HochbergM-bM-^@M-^Ys false discovery rate (FDR). Differences in relative expression due to treatment were considered significant at an FDR-adjusted P < 0.05. For a more stringent characterization between the two treatments, a 1.5-fold difference in mRNA expression was set as threshold among differentially expressed genes.

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Liver transcriptome modifications by nutrient restriction in early lactation Holstein cows challenged with intramammary lipopolysaccharide

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