Journal Article

β-Hydroxybutyrate Alleviates Low Glucose–Induced Apoptosis via Modulation of ROS-Mediated p38 MAPK Signaling

Wu Yongji, Chai Xuejun, Huang, Jian, Li Cixia, Yang, Jiping, Zhao Shanting, Pan Jiarong, Xue Yuhuan, Zhou Wentai, Zhu, Xiaoyan

2022

Overview

Hypoglycemia has emerged as a prominent complication in anti-diabetic drug therapy or negative energy balance of animals, which causes brain damage, cognitive impairment, and even death. Brain injury induced by hypoglycemia is closely related to oxidative stress and the production of reactive oxygen species (ROS). The intracellular accumulation of ROS leads to neuronal damage, even death. Ketone body β-hydroxybutyrate (BHBA) not only serves as alternative energy source for glucose in extrahepatic tissues, but is also involved in cellular signaling transduction. Previous studies showed that BHBA reduces apoptosis by inhibiting the excessive production of ROS and activation of caspase-3. However, the effects of BHBA on apoptosis induced by glucose deprivation and its related molecular mechanisms have been seldom reported. In the present study, PC12 cells and primary cortical neurons were used to establish a low glucose injury model. The effects of BHBA on the survival and apoptosis in a glucose deficient condition and related molecular mechanisms were investigated by using flow cytometry, immunofluorescence, and western blotting. PC12 cells were incubated with 1 mM glucose for 24 h as a low glucose cell model, in which ROS accumulation and cell mortality were significantly increased. After 24 h and 48 h treatment with different concentrations of BHBA (0 mM, 0.05 mM, 0.5 mM, 1 mM, 2 mM), ROS production was significantly inhibited. Moreover, cell apoptosis rate was decreased and survival rate was significantly increased in 1 mM and 2 mM BHBA groups. In primary cortical neurons, at 24 h after treatment with 2 mM BHBA, the injured length and branch of neurites were significantly improved. Meanwhile, the intracellular ROS level, the proportion of c-Fos+ cells, apoptosis rate, and nuclear translocation of NF-κB protein after treatment with BHBA were significantly decreased when compared with that in low glucose cells. Importantly, the expression of p38, p-p38, NF-κB, and caspase-3 were significantly decreased, while the expression of p-ERK was significantly increased in both PC12 cells and primary cortical neurons. Our results demonstrate that BHBA decreased the accumulation of intracellular ROS, and further inhibited cell apoptosis by mediating the p38 MAPK signaling pathway and caspase-3 apoptosis cascade during glucose deprivation. In addition, BHBA inhibited apoptosis by activating ERK phosphorylation and alleviated the damage of low glucose to PC12 cells and primary cortical neurons. These results provide new insight into the anti-apoptotic effect of BHBA in a glucose deficient condition and the related signaling cascade.

• Publisher: Springer Nature B.V
• Subject: Accumulation / Alternative energy sources / Apoptosis / Axons / Brain damage / Brain injury / c-Fos protein / Caspase-3 / Chemotherapy / Cognitive ability / Damage accumulation / Deprivation / Diabetes mellitus / Energy balance / Flow cytometry / Glucose / Head injuries / Hypoglycemia / Immunofluorescence / Intracellular / Ketones / MAP kinase / Molecular modelling / Neurons / NF-κB protein / Nuclear transport / Oxidative stress / Pheochromocytoma cells / Phosphorylation / Protein transport / Reactive oxygen species / Signal transduction / Signaling / Survival / Translocation / Western blotting