Regulation of lactate accumulation in bovine mammary epithelial cells by LPS-induced HIF-1α/MCT1 pathway

Xiaoye Cheng; Yijin Jiang; Xu Zhao; Nana Ma; Xiangzhen Shen

doi:10.1016/j.micpath.2024.107261

Regulation of lactate accumulation in bovine mammary epithelial cells by LPS-induced HIF-1α/MCT1 pathway

Microb Pathog. 2024 Dec 24:199:107261. doi: 10.1016/j.micpath.2024.107261. Online ahead of print.

Authors

Xiaoye Cheng¹, Yijin Jiang¹, Xu Zhao¹, Nana Ma¹, Xiangzhen Shen²

Affiliations

¹ Ministry of Education Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, 210095, Nanjing, China.
² Ministry of Education Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, 210095, Nanjing, China. Electronic address: xzshen@njau.edu.cn.

PMID: 39725042
DOI: 10.1016/j.micpath.2024.107261

Abstract

Lactate has been increasingly recognized for its role in diseases progression, necessitating a deeper understanding of its metabolic processes and regulatory mechanisms. This study aimed to evaluate the impact of lipopolysaccharide (LPS) on lactate accumulation in bovine mammary epithelial cells (BMECs) and to elucidate the underlying regulatory mechanisms. Further optimization of LPS treatment points was achieved by assessing the content of key glycolytic enzymes-hexokinases (HK), pyruvate kinase (PK) and pyruvate dehydrogenase (PDH)-as well as the expression levels of HK2, pyruvate dehydrogenase kinase4 (PDK4) and lactate dehydrogenase (LDHA). Our results indicate that LPS can promote intracellular glycolysis and inhibits pyruvate synthesis, thereby increasing lactate content. BMECs were cultured and divided into a control group (CON) and an LPS-stimulated group (10 μg/mL for 6 h, LPS group). LPS was found to upregulate expression levels of HIF-1α and MCT1, suggesting a role for HIF-1α and MCT1 in cellular glucose metabolism. To explore the effect of HIF-1α on lactate accumulation, BMECs were stimulated with a HIF-1α inducer (COCL₂) and HIF-1α inhibitor (DMBPA). COCL₂ was observed to promote lactate accumulation, while DMBPA inhibited it. Additionally, modulation of HIF-1α expression influenced the expression of MCT1, which is a crucial transporter for extracellular lactate influx. To investigate the specific impact of MCT1 on intracellular lactate, we utilized overexpression plasmids and small interfering RNA to modulate MCT1 expression. The findings indicate that while MCT1 expression alone does not affect intracellular lactate levels, it does modulate the changes induced by LPS. In conclusion, our study suggests that LPS regulates lactate accumulation in BMECs through the HIF-1α/MCT1 pathway, providing insights into the metabolic dysregulation associated with LPS-induced stress in dairy cattle.

Keywords: BMEC; HIF-1α/MCT1; LPS; Lactate accumulation.