Investigation of HCAR2 antagonists as a potential strategy to modulate bovine leukocytes

作     者：Laman K.Mamedova Kirby C.Krogstad Paiton O.McDonald Laxman Pokhrel Duy H.Hua Evan C.Titgemeyer Barry J.Bradford Laman K.Mamedova;Kirby C.Krogstad;Paiton O.McDonald;Laxman Pokhrel;Duy H.Hua;Evan C.Titgemeyer;Barry J.Bradford

作者机构：Department of Animal ScienceMichigan State UniversityEast LansingMichigan 48824USA Department of Animal Sciences and IndustryKansas State UniversityManhattanKS 66506USA Comparative Medicine and Integrative BiologyEast LansingMI 48824USA Department of ChemistryKansas State UniversityManhattanKS 66506USA 

出 版 物：《Journal of Animal Science and Biotechnology》 (畜牧与生物技术杂志（英文版）)

年 卷 期：2024年第15卷第4期

页      面：1567-1577页

核心收录：

学科分类：0905[农学-畜牧学] 09[农学] 

基　　金：the National Institutes of Health, National Institute of General Medical Sciences (R01 GM128659) for financial support The Attune Cytpix, located in the MSU Flow Cytometry Core Facility, is supported by the Equipment Grants Program, award #2022-70410-38419, from the U.S. Department of Agriculture (USDA), National Institute of Food and Agriculture (NIFA) 

主　　题：Flow cytometry GPR109A HM74A Ketosis 

摘      要：Background Dairy cows experiencing ketosis after calving suffer greater disease incidence and are at greater risk of leaving the herd. In vitro administration of beta-hydroxybutyric acid(BHBA;the primary blood ketone) has inhibitory effects on the function of bovine leukocytes. BHBA is a ligand of HCAR2 and the activation of these receptors promotes an anti-inflammatory response which may be related with immunosuppression observed in transition dairy cattle. The objective of this study was to identify and test antagonists for HCAR2 in bovine immune cells cultured with *** We observed expression of HCAR2 at the protein level within lymphocytes, monocytes, and granulocytes. The proportion of cells expressing HCAR2 tended to be greater in mid-lactation compared to early lactation cows;the increase was a result of increased proportion of T and B cells expressing HCAR2. Stimulation of HCAR2 with niacin or BHBA promoted Ca^(2+) mobilization in neutrophils and mononuclear cells. Mononuclear cells treated with BHBA had diminished intracellular Ca^(2+) responses when HCAR2 was knocked down by si RNA silencing, indicating Ca^(2+) mobilization was mediated by HCAR2 signaling. Two candidate antagonists for HCAR2, synthesized from niacin(NA-1 and NA-5), were tested;monocytes and neutrophils pre-treated with NA-1 and NA-5 had reduced Ca^(2+) mobilization after incubation with BHBA. Furthermore, NA-5 but not NA-1 prevented BHBA-associated reductions in cyclic *** We demonstrated that HCAR2 is present on bovine leukocytes and has greater expression later in lactation. We confirmed that BHBA and niacin derived HCAR2 antagonists alter bovine leukocyte activity. Our results demonstrate that both BHBA and niacin affect bovine leukocyte Ca^(2+) mobilization in a HCAR2-dependent manner.