title: Short communication: Arginase inhibition reduces the synthesis of casein in bovine mammary epithelial cells.
abstract: The main purpose of this work was to determine the effect of arginase inhibition via Nω-hydroxy-nor-l-arginine (nor-NOHA) on casein synthesis in bovine mammary epithelial cells (BMEC). Passage 2 BMEC isolated from dairy cows were seeded to 6-well plates and randomly divided into 4 treatments: (1) control [Dulbecco's modified Eagle medium:Nutrient Mixture F-12 medium (DMEM/F12)]; (2) nor-NOHA (DMEM/F12 + 1 mmol/L nor-NOHA); (3) nor-NOHA + arginine (DMEM/F12 + 1 mmol/L nor-NOHA + 3.2 mmol/L Arg); and (4) nor-NOHA + ornithine (DMEM/F12+ 1 mmol/L nor-NOHA + 1 mmol/L Orn). Then, we determined the activity of enzymes related to Arg metabolism and casein synthesis in BMEC and the proliferation of cells. The addition of nor-NOHA reduced the activity of arginase and ornithine decarboxylase but had no effect on the activity of nitric oxide synthase, and these responses were the same at the gene expression level. In addition, supplementation of nor-NOHA in BMEC reduced cellular proliferation and casein synthesis. Addition of Arg to nor-NOHA resulted in cellular proliferation and casein synthesis similar to that of nor-NOHA alone. In contrast, addition of Orn to the medium with nor-NOHA increased the synthesis of casein and cellular proliferation compared with Nor-NOHA. In conclusion, suppression of the Arg-arginase-Orn pathway reduced casein synthesis and cellular proliferation, which indicated that this pathway is an important regulator of the synthesis of casein in BMEC.
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China. Electronic address: mengzhiwangyz@126.com.
authors.forename: M Z
authors.initials: MZ
authors.lastname: Wang
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China.
authors.forename: L Y
authors.initials: LY
authors.lastname: Ding
authors.affiliation: School of Clinical Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, China.
authors.forename: C
authors.initials: C
authors.lastname: Wang
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China.
authors.forename: L M
authors.initials: LM
authors.lastname: Chen
authors.affiliation: Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801.
authors.forename: J J
authors.initials: JJ
authors.lastname: Loor
authors.affiliation: College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China. Electronic address: hongrongwang@sina.com.
authors.forename: H R
authors.initials: HR
authors.lastname: Wang
mesh_terms: D000818:Animals; D001119:Arginase / Q000037:antagonists & inhibitors*; D001120:Arginine / Q000494:pharmacology; D002364:Caseins / Q000096:biosynthesis*; D002417:Cattle; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D009569:Nitric Oxide / Q000378:metabolism
chemical_list: D002364:Caseins; D009569:Nitric Oxide; D001120:Arginine; D001119:Arginase
keywords: N(ω)-hydroxy-nor-l-arginine (nor-NOHA); arginine; mammary epithelial cell; milk casein; ornithine