Hepatic global DNA and peroxisome proliferator-activated receptor alpha promoter methylation are altered in peripartal dairy cows fed rumen-protected methionine

Abstract

The availability of Met in metabolizable protein (MP) of a wide range of diets for dairy cows is low. During late pregnancy and early lactation, in particular, suboptimal Met in MP limits its use for mammary and liver metabolism and also for the synthesis of S-adenosylmethionine, which is essential for many biological processes, including DNA methylation. The latter is an epigenetic modification involved in the regulation of gene expression, hence, tissue function. Thirty-nine Holstein cows were fed throughout the peripartal period (-21 d to 30 d in milk) a basal control (CON) diet (n=14) with no Met supplementation, CON plus MetaSmart (MS; Adisseo NA, Alpharetta, GA; n=12), or CON plus Smartamine M (SM; Adisseo NA; n=13). The total mixed ration dry matter for the close-up and lactation diets was measured weekly, then the Met supplements were adjusted daily and top-dressed over the total mixed ration at a rate of 0.19 (MS) or 0.07% (SM) on a dry matter basis. Liver tissue was collected on -10, 7, and 21 d for global DNA and peroxisome proliferator-activated receptor alpha (PPARα) promoter region-specific methylation. Several PPARα target and putative target genes associated with carnitine synthesis and uptake, fatty acid metabolism, hepatokines, and carbohydrate metabolism were also studied. Data were analyzed using PROC MIXED of SAS (SAS Institute Inc., Cary, NC) with the preplanned contrast CON versus SM + MS. Global hepatic DNA methylation on d 21 postpartum was lower in Met-supplemented cows than CON. However, of 2 primers used encompassing 4 to 12 CpG sites in the promoter region of bovine PPARA, greater methylation occurred in the region encompassing -1,538 to -1,418 from the transcription start site in cows supplemented with Met. Overall expression of PPARA was greater in Met-supplemented cows than CON. Concomitantly, PPARA-target genes, such as ANGPTL4, FGF21, and PCK1, were also upregulated overall by Met supplementation. The upregulation of PPARα target genes indicates that supplemental Met, likely through the synthesis of S-adenosylmethionine, activated PPARA-regulated signaling pathways. Upregulation of hepatic PPARA has been associated with improved lipid metabolism and immune function, both of which were reported in companion publications from this study. In turn, those positive effects resulted in improved postpartal health and performance. Further research is needed to study more closely the mechanistic connections between global DNA and promoter region-specific PPARA methylation with PPARA expression and functional outcomes in liver.

circRNA_0046367 Prevents Hepatoxicity of Lipid Peroxidation: An Inhibitory Role against Hepatic Steatosis

“…miR-34a influences the expression of multiple genes within steatosis-inducing signaling pathways, especially PPAR signaling pathway (rno03320) [ 44 , 45 ]. Most of these PPAR signaling members (i.e., SCD1, ACSL1, ACSL4, and PCK1) could be transcriptionally activated by PPAR α [ 46 – 49 ], which is then qualified for the key target gene of miR-34a. Except for the circRNA_0046367/miR-34a interaction, there were also algorithm-based proofs for the complementation between “seed sequence” of miR-34a and 3′ untranslated region (3′ UTR) of PPAR α in the present experiments.…”

Gene Regulation in Ruminants: A Nutritional Perspective

“…In ruminants, supplementation of rumen-protected to dairy cows resulted in a prepartal upregulation of DNMT3A, a gene that encodes for a DNA methyltransferase in charge of the de novo methylation of the DNA [72]. And, more recently, the significance of these findings was confirmed by observing alterations due to methionine supplementation in the liver of transition dairy cows in terms of global DNA methylation and specific region methylation of an important TF, the peroxisome proliferatoractivated receptor alpha PPARα [8]. The characteristics and uniqueness of this TF within the context of the transition dairy cow were initially presented by Drackley [73], and since then, this nuclear receptor has become an exciting area of research in dairy cattle nutrigenomics (i.e., nutrient-gene interaction) [10].…”

“…Some transcription factors can create a secondary wave of change in gene expression by upregulating the transcription of subsequent transcription factor [6], and previously, it has been proposed that transcription factors may work in an orchestrated fashion creating a network of transcription factors that respond to dietary effects [7]. An alternative effect from intermediate metabolites is the production of DNA or histone modifications by changing the available information in the DNA [8], also known as epigenetic effects. A potential epigenetic mechanism mediated by transcription factors is the increased transcription of noncoding RNAs such as microRNAs [9], which upon transcription these small RNAs will target coding RNA prior to their translation into proteins.…”

Short communication: The effect of increasing concentrations of different methionine forms and 2-hydroxy-4-(methylthio)butanoic acid on genes controlling methionine metabolism in primary bovine neonatal hepatocytes

“…In dairy cows, the d-Met isomer cannot be directly used by the mammary gland; instead, it is converted into l-Met, the proteogenic isomer, in liver and other extramammary tissues (Lapierre et al, 2012). Despite this need for conversion of d-Met to l-Met, supplementation of rumen-protected dl-Met or the isopropyl ester of 2-hydroxy-4-(methylthio)butanoic acid (HMBi) in dairy cows has been associated with improved milk production, milk protein concentrations, and nitrogen utilization (St-Pierre and Sylvester, 2005;Chen et al, 2011;Osorio et al, 2013), better immunometabolic status (Osorio et al, 2014a,b), and modified hepatic gene expression and DNA methylation pattern (Osorio et al, 2014a(Osorio et al, , 2016.…”