Effect of moxibustion on autophagy lysosome function mediated by mTOR/TFEB pathway and lncRNA H19 expression in APP/PS1 double transgenic mice

Abstract

To observe the effect of moxibustion (Moxi) at acupoints of Governor Vessel on autophagy lysosomal function and lncRNA H19 in amyloid precursor protein/presenilin 1 (APP/PS1) double transgenic Alzheimer's disease (AD) mice, so as to explore its underlying mechanisms in relieving AD. Fifty two male APP/PS1 double transgenic AD mice were randomly divided into model, Moxi, Moxi+inhibitor and medication (rapamycin) groups, with 13 mice in each group. Other 13 male C57BL/6J mice of the same age were selected as the control group. The mice of the Moxi group received aconite cake-separated Moxi stimulation at "Baihui" (GV20), "Dazhui"(GV14) and "Fengfu" (GV16), for 15 min, those of the Moxi+inhibitor group received intraperitoneal injection of 3-methyladenine (an inhibitor of PI3K for suppressing autophagy) 1.5 mg· kg-1 · d-1 on the basis of Moxi, and those of the medication group received intraperitoneal injection of rapamycin 2 mg· kg-1 · d-1. The treatment was conducted once daily for 2 weeks. The mouse's learning-memory ability was detected by Morris water maze tests. The hippocampus tissue was sampled for observing the formation of autophagy by using transmission electron microscope, detecting the expression of Aβ_(1-42) protein with immunohistochemical staining, and for detecting the expression levels of long noncoding RNA H19 (lncRNA H19), mammalian target of rapamycin kinase (mTOR), nuclear transcription factor EB (TFEB), Cathepsin D and lysosome associated membrane protein-1 (LAMP1) genes and proteins as well as microtubule associated protein 1 light chain 3B (LC3B)-Ⅱ/LC3B-Ⅰand autophagy protein p62 protein by quantitative real-time PCR and Western blot, respectively. In contrast to the control group, the model group had an evident increase in the escape latency of Morris water maze test, and in the expression levels of Aβ_(1-42) protein, lncRNA H19 mRNA, mTOR mRNA and protein, and p62 protein (P<0.05), and a significant decrease in the expression levels of TFEB, Cathepsin D, LAMP1 mRNAs and proteins and LC3B-Ⅱ/LC3B-Ⅰ (P<0.05). After the treatment and relevant to the model and Moxi+inhibitor groups, both the Moxi and medication groups had an obvious down-regulation in the levels of latency of Morris water maze, expression levels of Aβ_(1-42) protein, lncRNA H19 mRNA, mTOR mRNA and protein, and p62 protein (P<0.05), and a significant up-regulation in the levels of TFEB, Cathepsin D, LAMP1 mRNAs and proteins and LC3B-Ⅱ/LC3B-Ⅰ (P<0.05). Moxi at acupoints of Governor Vessel can improve cognitive function of AD mice, which may be associated with its functions in inhibiting mTOR/TFEB pathway by down-regulating the expression of lncRNA H19, improving autophagy lysosomal function, promoting autophagy and clearing away Aβ1-42 in the hippocampus.