β-hydroxybutyrate impairs monocyte function via the ROS-NLR family pyrin domain-containing three inflammasome (NLRP3) pathway in ketotic cows

Zhihao Dong; Xudong Sun; Yan Tang; Shengbin Luo; Hongdou Jia; Qiushi Xu; Qianming Jiang; Juan J Loor; Wei Xu; Chuang Xu

doi:10.3389/fvets.2022.925900

β-hydroxybutyrate impairs monocyte function via the ROS-NLR family pyrin domain-containing three inflammasome (NLRP3) pathway in ketotic cows

Front Vet Sci. 2022 Aug 29:9:925900. doi: 10.3389/fvets.2022.925900. eCollection 2022.

Authors

Zhihao Dong¹, Xudong Sun¹, Yan Tang¹, Shengbin Luo¹, Hongdou Jia¹, Qiushi Xu¹, Qianming Jiang², Juan J Loor², Wei Xu³, Chuang Xu¹

Affiliations

¹ Heilongjiang Provincial Key Laboratory of Prevention and Control of Bovine Diseases, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China.
² Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, IL, United States.
³ Department of Biosystems, Biosystems Technology Cluster, KULeuven, Geel, Belgium.

Abstract

Cows with ketosis display severe metabolic stress and immune dysfunction which renders them more susceptible to infections. Monocytes, one of the major subtypes of white blood cells, play an important role in innate immune defense against infections. Thus, the aim of this study was to investigate alterations in immune function, reactive oxygen species (ROS) production and activity of the NLR family pyrin domain containing 3 (NLRP3) inflammasome pathway in monocytes (CD14⁺) of cows with clinical ketosis (CK). Twelve healthy multiparous Holstein cows [blood β-hydroxybutyrate (BHB) concentration < 1.2 mM] and 12 cows with CK (BHB > 3.0 mM) at 3 to 14 days in milk were used for blood sample collection. To determine effects of BHB on phagocytosis, ROS and protein abundance of the NLRP3 inflammasome pathway in vitro, monocytes isolated from healthy cows were treated with 3.0 mM BHB for 0, 6, 12 or 24 h. Dry matter intake (22.7 vs. 19.0 kg) was lower in cows with CK. Serum concentrations of fatty acids (0.30 vs. 0.88 mM) and BHB (0.52 vs. 3.78 mM) were greater in cows with CK, whereas concentration of glucose was lower (4.09 vs. 2.23 mM). The adhesion, migration and phagocytosis of monocytes were lower in cows with CK, but apoptosis and ROS content were greater. Protein abundance of NLRP3, cysteinyl aspartate specific proteinase 1 (caspase 1) and interleukin-1B p17 (IL1B p17) were greater in monocytes of cows with CK, while abundance of NADPH oxidase isoform 2 (NOX2) was lower. Compared with 0 h BHB, ROS content and apoptosis were greater in the monocytes challenged for 6, 12 or 24 h BHB. Compared with 0 h BHB, protein abundance of NLRP3, caspase 1, IL1B p17 and concentration of IL1B in medium were greater in the monocytes challenged for 6, 12 or 24 h BHB. However, compared with 0 h BHB, protein abundance of NOX2 and phagocytosis of monocytes were lower in the monocytes challenged for 6, 12 or 24 h BHB. Overall, the data suggested that exogenous BHB activated the ROS-NLRP3 pathway, which might be partly responsible for immune dysfunction of dairy cows with CK.

Keywords: ketosis; monocytes; oxidative stress; phagocytosis; β-hydroxybutyric acid.