Dataset Information

Milk fat miRNome changes in response to LPS challenge in Holstein cows

ABSTRACT: Cows were fed a lactation diet at ad libitum intake (n = 6). At 27±3 days in milk, cows were injected with 50 µg of LPS E. coli in one healthy rear mammary quarter. Milk samples were collected just before LPS challenge (LPS-) and 6.5 h after LPS challenge (LPS+) from the same cows. Microarray analysis was performed using customized 8x60K ruminant miRNA microarrays to compare LPS- to LPS+ miRNome. MiRNome comparison between LPS- and LPS+ identified 37 differentially abundant miRNAs (q-value ≤ 0.05)

ORGANISM(S): Bos taurus Ovis aries Capra hircus

PROVIDER: GSE229476 | GEO | 2023/10/23

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: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.