Effects of ORAI calcium release-activated calcium modulator 1 (ORAI1) on neutrophil activity in dairy cows with subclinical hypocalcemia1. (12th July 2019)

• Record Type: Journal Article
• Authors: Zhang, Bingbing; Guo, Han; Yang, Wei; Li, Ming; Zou, Ying; Loor, Juan J; Xia, Cheng; Xu, Chuang
• Is Part Of: Journal of animal science. Volume 97:Number 8(2019)
• Page Start: 3326
• Page End: 3336
• Publication Date: 2019-07-12
• Subjects: cattle -- hypocalcemia -- PMNL -- immune function; Livestock -- Periodicals; Livestock; Electronic journals; Periodicals; 636.005
• DOI: 10.1093/jas/skz209
• Languages: English
• ISSNs: 0021-8812

Abstract

Abstract: Hypocalcemia in dairy cows is often associated with inflammation-related disorders such as metritis and mastitis. The protein encoded by the Ca 2+ release-activated calcium modulator 1 (ORAI1 ) gene is a membrane Ca 2+ channel subunit that is activated when Ca 2+ stores are depleted. Polymorphonuclear neutrophils (PMNL ) have a crucial role in the defense against infection through migration, adhesion, chemotaxis, phagocytosis, and reactive oxygen species (ROS ) production in response to pathogens. Whether hypocalcemia affects the activity of PMNL and if ORAI1 is involved remains unknown. To address this, PMNL were isolated at 3 d of calving from dairy cows diagnosed as clinically healthy ( n = 20, CONTROL) or with plasma concentration of calcium < 2.0 mmol/L as a criterion for diagnosis of subclinical hypocalcemia ( n = 20, HYPOCAL). PMNL isolated from both groups of cows were treated with or without the sarcoendoplasmic Ca 2+ ATPase inhibitor thapsigargin, Ca 2+ ionophore Ionomycin, and ORAI1 blocker 2APB. The intracellular Ca 2+ concentration, ORAI1 abundance, ROS, phagocytosis rate, migration, and adhering capacity of treated PMNL were evaluated. Some of the in vitro assays also included use of small interfering ORAI1 RNA (siORAI1 ), 100 nM 1, 25(OH)2 D3, or 100 nM parathyroid hormone (PTH ). Intracellular Ca 2+ concentration was markedly lower in HYPOCAL. In addition, ORAI1 was detected in PMNL plasma membrane via FACS and was markedly lower in cows with HYPOCAL. Migration, adhesion capacity, and phagocytosis rate of PMNL were lower in response to HYPOCAL. Furthermore, plasma and PMNL concentration of nucleosome assembly protein (NAP2 ) and pro-platelet basic protein (CXCL7 ) was markedly lower with HYPOCAL. All these changes were associated with lower ROS production by PMNL. Thapsigargin and ionomycin treatment in vitro increased ORAI1 expression, migration of PMNL, adhering capacity, phagocytosis rate, and ROS production; conversely, those effects were abrogated by siORAI1 and ORAI1 inhibitor 2APB treatment. Also cytosolic Ca 2+ concentration and ORAI1 abundance were increased by 1, 25(OH)2 D3 and PTH supplementation. Overall, the data indicate that failure of PMNL to uptake Ca 2+ due to downregulation of ORAI1 during subclinical hypocalcemia is a factor contributing to impaired PMNL function. In addition, plasma PTH or 1, 25(OH)2 D3 could regulate ORAI1 and also participate in the regulation of PMNL activity.