Electroacupuncture ameliorates cognitive impairment in APP/PS1 mouse by modulating TFEB levels to relieve ALP dysfunction

Abstract

Recently, the underlying mechanisms of acupuncture on the effects of Alzheimer's disease (AD) treatment have not been fully elucidated. Defects in ALP (autophagy-lysosomal pathway) and TFEB (transcription factor EB) play critical roles in AD. Our previous studies have demonstrated that electroacupuncture (EA) can ameliorate both β-amyloid (Aβ) pathology and cognitive function in APP/PS1 mice. However, the effects of EA on the expression of ALP and TFEB and their potential mechanisms require further investigation. Twenty-eight male APP/PS1 mice were randomly divided into Tg and Tg + EA groups, and 14 C57BL/6 mice served as the wild-type (WT) group. After 1 week of adaptation to the living environment, mice in the Tg + EA group were restrained in mouse bags and received manual acupuncture at Baihui (GV20) acupoint and EA stimulation at bilateral Yongquan (KI1) acupoints, using the same restraint method for WT and Tg groups. The intervention was applied for 15 min each time, every other day, lasting for six weeks. After intervention, the spatial learning and memory of the mice was assessed using the Morris water maze test. Hippocampal Aβ expression was detected by immunohistochemistry and ELISA. Transmission electron microscopy (TEM) was used to observe autophagic vacuoles and autolysosomes in the hippocampus. Immunofluorescence method was applied to examine the expression of TFEB in CA1 region of the hippocampus and the co-localization of CTSD or LAMP1 with Aβ. Western blot analysis was performed to evaluate the changes of LC3, p62, CTSD, LAMP1, TFEB and n-TFEB (nuclear TFEB) in the hippocampus. The findings of behavioral assessment indicated that EA alleviated the cognitive impairment of APP/PS1 mice. Compared with the WT group, the Tg group showed significant cognitive decline and abnormalities in ALP and TFEB function (P < 0.01 or P < 0.05). However, these abnormal changes were alleviated in the Tg + EA group (P < 0.01 or P < 0.05). The Tg group also showed more senile plaques and ALP dysfunction features, compared with the WT group, and these changes were alleviated by EA. In conclusion, this study highlights that EA ameliorated Aβ pathology-related cognitive impairments in the APP/PS1 model associated with ALP and TFEB dysfunction.

Keywords: APP/PS1 mice; Alzheimer’s disease; Autophagy-lysosomal pathway; Electroacupuncture; Transcription factor EB.