Shenzhiling oral liquid protects the myelin sheath against Alzheimer's disease through the PI3K/Akt-mTOR pathway.

Shenzhiling oral liquid (SZL), a traditional Chinese medicine (TCM) compound, is firstly approved by the Chinese Food and Drug Administration (CFDA) for the treatment of mild to moderate Alzheimer's disease (AD). SZL is composed of ten Chinese herbs, and the precise therapy mechanism of its action to AD is far from fully understood. The purpose of this study was to observe whether SZL is an effective therapy for amyloid-beta (Aβ)-induced myelin sheath and oligodendrocytes impairments. Notably, the primary aim was to elucidate whether and through what underlying mechanism SZL protects the myelin sheath through the PI3K/Akt-mTOR signaling pathway in Aβ42-induced OLN-93 oligodendrocytes in vitro. APP/PS1 mice were treated with SZL or donepezil continuously for three months, and Aβ42-induced oligodendrocyte OLN-93 cells mimicking AD pathogenesis of myelin sheath impairments were incubated with SZL-containing serum or with donepezil. LC-MS/MS was used to analysis the active components of SZL and SZL-containing serum. The Y maze test was administered after 3 months of treatment, and the hippocampal tissues of the APP/PS1 mice were then harvested for observation of myelin sheath and oligodendrocyte morphology. Cell viability and toxicity were assessed using CCK-8 and lactate dehydrogenase (LDH) release assays, and flow cytometry was used to measure cell apoptosis. The expression of the myelin proteins MBP, PLP, and MAG and that of Aβ42 and Aβ40 in the hippocampi of APP/PS1 mice were examined after SZL treatment. Simultaneously, the expression of p-PI3K, PI3K, p-Akt, Akt, p-mTOR, and mTOR were also examined. The expression of proteins, including CNPase, Olig2, NKX2.2, MBP, PLP, MAG, MOG, p-PI3K, PI3K, p-Akt, Akt, p-mTOR, and mTOR, was determined by immunofluorescence and Western blot, and the corresponding gene expression was evaluated by qPCR in Aβ42-induced OLN-93 oligodendrocytes. LC-MS/MS detected a total of 126 active compounds in SZL-containing serum, including terpenoids, flavones, phenols, phenylpropanoids and phenolic acids. SZL treatment significantly improved memory and cognition in APP/PS1 mice and decreased the G-ratio of myelin sheath, alleviated myelin sheath and oligodendrocyte impairments by decreasing Aβ42 and Aβ40 accumulation and increasing the expression of myelin proteins MBP, PLP, MAG, and PI3K/Akt-mTOR signaling pathway associated protein in the hippocampi of APP/PS1 mice. SZL-containing serum also significantly reversed the OLN-93 cell injury induced by Aβ42 by increasing cell viability and enhanced the expression of MBP, PLP, MAG, and MOG. Meanwhile, SZL-containing serum facilitated the maturation and differentiation of oligodendrocytes in Aβ42-induced OLN-93 cells by heightening the expression of CNPase, Olig2 and NKX2.2. SZL-containing serum treatment also fostered the expression of p-PI3K, PI3K, p-Akt, Akt, p-mTOR, and mTOR, indicating an activating PI3K/Akt-mTOR signaling pathway in OLN-93 cells. Furthermore, the effects of SZL on myelin proteins, p-Akt, and p-mTOR were clearly inhibited by LY294002 and/or rapamycin, antagonists of PI3K and m-TOR, respectively. Our findings indicate that SZL exhibits a neuroprotective effect on the myelin sheath by promoting the expression of myelin proteins during AD, and its mechanism of action is closely related to the activation of the PI3K/Akt-mTOR signaling pathway.

Zheng M ，Liu Z ，Mana L ，Qin G ，Huang S ，Gong Z ，Tian M ，He Y ，Wang P ... -  《-》

Study on myelin injury of AD mice treated with Shenzhiling oral liquid in the PI3K/Akt-mTOR pathway.

Wang Y ，Chen F ，Wang P ，Mana L ，Sheng N ，Huang S ... -  《-》

Shenzhiling Oral Liquid Protects STZ-Injured Oligodendrocyte through PI3K/Akt-mTOR Pathway.

White matter degeneration and demyelination are nonnegligible pathological manifestations of Alzheimer's disease (AD). The damage of myelin sheath consisting of oligodendrocytes is the basis of AD's unique early lesions. Shenzhiling oral liquid (SZL) was the effective Chinese herbal compound approved by the Food and Drug Administration (FDA) for the treatment of AD in China, which plays the exact therapeutic role in clinical AD patients. However, its molecular mechanism remains unclear to date. For this purpose, an in vitro mode of streptozotocin- (STZ-) induced rat oligodendrocyte OLN-93 cell injury was established to mimic the pathological changes of myelin sheath of AD and investigate the mechanism of SZL protecting injured OLN-93 cell. The results showed that STZ can decrease cell viability and downregulate the activity of PI3K/Akt-mTOR signalling pathway and the expression of myelin sheath-related proteins (MBP, MOG, and PLP) in OLN-93 cells. Both SZL-medicated serum and donepezil (positive control) can protect cells from STZ-caused damage. SZL-medicated serum increased OLN-93 cell viability in a dose- and time-dependent manner and enhanced the activity of PI3K/Akt-mTOR signalling pathway. The inhibitor of PI3K (LY294002) inhibited the protective effect of SZL-medicated serum on the STZ-injured OLN-93 cells. Furthermore, rapamycin, the inhibitor of mTOR, inhibited the promotion of cell viability and upregulation of p-mTOR and MBP caused by SZL-medicated serum. In conclusion, our data indicate that SZL plays its therapeutic role on AD by promoting PI3K/Akt-mTOR signalling pathway of oligodendrocytes. Thus, the present study may facilitate the therapeutic research of AD.

Liu Z ，Qin G ，Mana L ，Huang S ，Wang Y ，Wang P ... -  《-》

Chinese formula Guben-Jiannao Ye alleviates the dysfunction of circadian and sleep rhythms in APP/PS1 mice implicated in activation of the PI3K/AKT/mTOR signaling pathway.

The Chinese formula Guben-Jiannao Ye (GBJNY) formula has a long history of usage in traditional Chinese medicine (TCM) for the treatment of learning and memory disorders as well as senile insomnia. This formulation is derived from Sun Simiao's five tonic pills. Furthermore, modern pharmacological investigations have revealed its ability to improve cognitive impairment and ameliorate sleep-wake circadian rhythm disorders. However, the precise mechanism underlying its efficacy remains elusive. The current research explored the modulatory effects and possible mechanisms of GBJNY in circadian rhythm sleep-wake disorders and cognitive dysfunction in Alzheimer's disease using transcriptome sequencing and experimental validation. The LC-MS/MS tandem technology was utilized to qualitatively discern the active components present in GBJNY. The APP/PS1 mice received continuous treatment with GBJNY or Melatonin for 3 months. The learning and memory abilities of mice were assessed utilizing the Morris water maze (MWM) test, while sleep changes were studied utilizing the electroencephalogram (EEG) and electromyogram (EMG). Concurrently, mice's hippocampus clock gene rhythmicity was investigated. Subsequently, we employed HE staining, Golgi staining, and immunofluorescence to observe GBJNY's impact on synaptic damage and neuronal loss. We performed high-throughput sequencing to analyze the mRNA expression profiles of mice, aiming to identify differentially expressed genes (DEGs). Subsequently, we conducted GO and KEGG enrichment analyses to explore associated signaling pathways. Furthermore, we evaluated the expression levels of proteins involved in the PI3K/AKT/mTOR pathway and Aβ deposition in the hippocampus of mice. Through this comprehensive approach, we sought to elucidate and validate the potential mechanisms of action of GBJNY in APP/PS1 mice. Results showed 216 DEGs. Following this, we conducted GO enrichment and KEGG pathway analyses to delve deeper into the distinctions and fundamental functions of the mRNA target genes. The enrichment analysis underscored the prominence of the PI3K/Akt/mTOR signaling pathway as the most pivotal among them. Through in vivo experiments, it was further demonstrated that the administration of GBJNY enhanced memory and learning capacities in APP/PS1 mice. Additionally, GBJNY treatment resulted in alterations in the sleep-wake circadian rhythm, characterized by reduced wakefulness and an increase in non-rapid eye movement (NREM) sleep. Moreover, alterations in the peak expression of Per1, Per2, Clock, Cry1, Cry2, and Bmal1 mRNA were noted in the hippocampus of treated mice. Particularly noteworthy were the observed reductions in amyloid-beta (Aβ) deposition within the hippocampus, improvements in neuronal synaptic integrity, and upregulation of mTOR, Akt, and PI3K protein expression in the hippocampal region. These findings underscore the critical involvement of the PI3K/Akt/mTOR signaling pathway in mitigating disturbances in sleep-wake circadian rhythms. GBJNY enhanced the cognitive performance of APP/PS1 mice and altered clock gene expression patterns, alleviating sleep-wake circadian rhythm disruptions. The fundamental mechanism appears to be linked to the PI3K/Akt/mTOR pathway regulation, offering a foundation for potential clinical applications.

Mao JQ ，Cheng L ，Zhang YD ，Xie GJ ，Wang P ... -  《-》

Downregulation of PI3K/Akt/mTOR signaling pathway in curcumin-induced autophagy in APP/PS1 double transgenic mice.

Autophagy is a lysosomal degradation pathway, which is essential for cell survival, proliferation, differentiation and homeostasis. It is well known that beta-amyloid (Aβ) aggregation is one of key characteristics for Alzheimer's disease (AD), which triggers a complex pathological cascade, leading to neurodegeneration. Recent studies have shown that Aβ peptide is generated from amyloid β precursor protein (APP) during autophagic turnover of APP-rich organelles by autophagy. Aβ generation during normal autophagy is subsequently degraded by lysosomes. Curcumin, a nature plant extraction, has been reported to inhibit the generation and deposition of Aβ; however, the underlying mechanisms are not fully understood yet. In the present study, we reported that curcumin treatment not only attenuated cognitive impairment detected by Morris water maze test, but also inhibited the generation of Aβ investigated by immunohistochemistry in APP/PS1 double transgenic AD mice. Moreover, curcumin induced autophagy in the mice, evidenced by LC3 immunofluorescence analysis and western blot assays on LC3. Furthermore, we found that curcumin significantly decreased the expression of Phosphatidylinositol 3-Kinase (PI3K), phosphorylated Akt and rapamycin (mTOR) at protein levels, respectively. Taken together, our data suggests that curcumin inhibits Aβ generation and induces of autophagy by downregulating PI3K/Akt/mTOR signaling pathway, and further shows a neuroprotective effect. Meanwhile curcumin might be a candidate neuroprotective agent for AD patients treatment by inducing autophagy.

Wang C ，Zhang X ，Teng Z ，Zhang T ，Li Y ... -  《-》