pim kinase inhibitor br Short Communication Free fatty acid

Short Communication Free fatty pim kinase inhibitor receptors (FFAR) play significant roles in energy metabolism (Brown et al., 2005; Ichimura et al., 2009). The receptor FFAR1 is involved in insulin secretion in humans (Meidute Abaraviciene et al., 2013). Activation of the receptor FFAR2 increases lipid accretion and reduces lipolysis in mice (Hong et al., 2005). Short-chain fatty acids activate FFAR2, whereas medium- and long-chain fatty acids are ligands for FFAR1 (Brown et al., 2003; Kim et al., 2013; Yonezawa et al., 2013). Functionalities of bovine FFAR1 and FFAR2 have been demonstrated. Initially, Wang et al. (2009) showed decreasing acetate-, propionate-, and butyrate-activated cyclic AMP using bovine FFAR2-transfected Chinese hamster ovary (CHO) cells. Hudson et al. (2012) established pharmacological differences between human and bovine FFAR2; for example, by using the extracellular signal-regulated kinase1/2 phosphorylation assay. Manosalva et al. (2015) cloned and characterized bovine FFAR1 by measuring intracellular calcium levels after receptor activation and demonstrated effects of receptor activation on production of bovine neutrophil reactive oxygen species. Friedrichs et al. (2014) observed the greatest mRNA abundance of FFAR1 in liver compared with other tissues, which decreased after parturition. The mRNA of FFAR2 in liver, which is not regulated during the peripartal period, is higher compared with that in muscle but comparable to that in subcutaneous adipose tissue. Protein data on both receptors in bovine liver is not available yet. Because of the general association of FFAR1 and FFAR2 with energy metabolism in other species, the ubiquitous importance of the signal transduction pathways used by these receptors, and the importance of their ligands for bovine liver metabolism, we hypothesize that both receptors could be involved in the regulation of liver metabolism of dairy cows during the peripartal period. The increasing synthesis of BHB postpartum is driven by increasing fatty acid concentrations but also by other intermediates such as lactate and ketogenic amino acids and could be related to individual differences in the gluconeogenic capacity with propionate as main precursor for gluconeogenesis, as discussed by McCarthy et al. (2015a). High concentrations of BHB postpartum are related to changes in the abundance of enzymes linked to the reduction of hepatic β-oxidation in bovine liver (Li et al., 2012). Simultaneously, with increasing ketone body formation and fatty acid concentrations, the gluconeogenic activity of the liver is decreased (Grummer, 1993; McCarthy et al., 2015b). A higher prevalence of subclinical ketosis is observed when BHB exceeds 1.2 mmol/L postpartum (Suthar et al., 2013). Thirteen multiparous German Holstein cows, in their second to fourth lactation, were selected from a previous study (Schäff et al., 2012) based on their individual peak in plasma BHB concentrations in wk 2 or 3 postpartum: high BHB (H-BHB; 1.05 to 2.57 mmol/L, mean 1.59 mmol/L; n = 8) and low BHB (L-BHB; 0.43 to 0.76 mmol/L, mean 0.65 mmol/L; n = 5) concentrations. The cows had a milk yield of more than 10,000 kg/305 d in a previous lactation, and were selected according to their DGAT1 genotype (K232A) to exclude differences in fat metabolism based on this trait. Cows were housed in tiestalls and were fed twice daily (0630 and 1530 h) 1 of 3 different TMR (Supplemental Table S1 for further information on the diet; https://doi.org/10.3168/jds.2016-11021) corresponding to their physiological state; that is, far-off dry period (wk 7 to 4 before expected calving; 5.9 MJ of NEL/kg of DM; CP 126 g/kg of DM), close-up dry period (wk 3 until calving; 6.5 MJ of NEL/kg of DM; CP 137 g/kg of DM), and lactation (7 MJ of NEL/kg of DM; CP 163 g/kg of DM) according to the recommendations of German Society of Nutritional Physiology (GfE, 2001). All procedures were conducted in agreement with the recommendations for the use of animals as experimental subjects of the State Government in Mecklenburg-West Pomerania (Registration No. LALLF M-V/TSD/7221.3-2.1-021/09). Blood samples were taken weekly, starting at d −34 relative to parturition until slaughter at d 40, from the jugular vein into EDTA-containing tubes (no. 4550036; Greiner Bio-One, Frickenhausen, Germany) and centrifuged at 1,565 × g for 20 min at 4°C. The obtained plasma was stored at −80°C until analyzed. Liver tissue samples were taken by biopsy at d −34, −17, 3, 18, and 30 relative to parturition and by sampling at slaughter (d 40). Tissue obtained was immediately frozen and stored at −80°C for further analysis. Further details on animal management and samples collection, including data on BHB concentrations and energy balance, were published by Schäff et al. (2012, 2013). Data on protein extraction, SDS-PAGE, Western blotting, and immunohistochemistry are provided as supplemental data (https://doi.org/10.3168/jds.2016-11021).