Traditional Chinese medicine for the treatment of Alzheimer's disease: A focus on the microbiota-gut-brain axis

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

ETHNOPHARMACOLOGICAL RELEVANCE

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.

AIM OF THE STUDY

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.

MATERIALS AND METHODS

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

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.

CONCLUSIONS

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.

Dajianzhong decoction ameliorated D-gal-induced cognitive aging by triggering mitophagy in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Dajianzhong decoction (DJZ) is a classical famous formula for treating yang-deficiency-syndrome in traditional Chinese medicine and recorded in Jin-Kui-Yao-Lue in Dynasty of Dong Han. Cognitive aging can present similar features of mitochondrial energy deficits to the clinical features of Yang deficiency. However, there is poor understanding of the effects of DJZ treatment on mitophagy in cognitive aging.

AIM OF THE STUDY

The aims of this work were to decipher the effectiveness and mechanism of DJZ against cognitive aging, focusing on mitophagy.

MATERIALS AND METHODS

YFP-Parkin HeLa cells, D-galactose (D-gal) -induced mice (500 mg/kg for 35 d, s. c.) and SH-SY5Y cells (80 mg/ml for 6 h) were established. Firstly, the formation of YFP-Parkin puncta (a well-known mitophagy marker) in YFP-Parkin HeLa cells was employed to discover the mitophagy induction of DJZ. Moreover, the genes and proteins related to PINK1/Parkin pathway and mitochondrial functions were evaluated after treatment with DJZ in vivo (3.5 g/kg or 1.75 g/kg, i. g, 35 d) and in vitro (0.2, 2 and 20 μg/ml, 12 h). Furthermore, the effectiveness of DJZ (3.5 g/kg or 1.75 g/kg, i. g) for alleviating cognitive aging and nerve damage was measured in D-gal mice. Finally, siPINK1 was applied to reverse validation of DJZ in vitro.

RESULTS

The formation of YFP-Parkin puncta in YFP-Parkin HeLa cells was markedly induced by DJZ in a dose-dependent manner. The immunofluorescence intensity of Parkin and the protein expression of Parkin in mitochondrial membrane in D-gal mice were significantly increased after treatment of DJZ. The inhibition of PINK1/Parkin pathway in D-gal-induced mice and SH-SY5Y cells was significantly activated by DJZ. Simultaneously, the impairment of mitochondrial functions induced by D-gal were markedly reversed by DJZ. In addition, DJZ significantly ameliorated the neuropathological injury and cognitive declines in D-gal mice. Finally, after PINK1 was knocked down by siPINK1 in vitro, the neuroprotective effects of DJZ and the Parkin enhancement effect of DJZ were markedly reversed.

CONCLUSION

Our findings firstly showed DJZ could relieve cognitive aging through facilitating PINK1/Parkin-mediated mitophagy to protect against mitochondrial functions, indicating DJZ may be regarded as a promising intervention in cognitive aging.

Danggui Shaoyao San: comprehensive modulation of the microbiota-gut-brain axis for attenuating Alzheimer's disease-related pathology

Background: Alzheimer's disease (AD), an age-associated neurodegenerative disorder, currently lacks effective clinical therapeutics. Traditional Chinese Medicine (TCM) holds promising potential in AD treatment, exemplified by Danggui Shaoyao San (DSS), a TCM formulation. The precise therapeutic mechanisms of DSS in AD remain to be fully elucidated. This study aims to uncover the therapeutic efficacy and underlying mechanisms of DSS in AD, employing an integrative approach encompassing gut microbiota and metabolomic analyses. Methods: Thirty Sprague-Dawley (SD) rats were allocated into three groups: Blank Control (Con), AD Model (M), and Danggui Shaoyao San (DSS). AD models were established via bilateral intracerebroventricular injections of streptozotocin (STZ). DSS was orally administered at 24 g·kg-1·d-1 (weight of raw herbal materials) for 14 days. Cognitive functions were evaluated using the Morris Water Maze (MWM) test. Pathological alterations were assessed through hematoxylin and eosin (HE) staining. Bloodstream metabolites were characterized, gut microbiota profiled through 16S rDNA sequencing, and cortical metabolomics analyzed. Hippocampal proinflammatory cytokines (IL-1β, IL-6, TNF-α) were quantified using RT-qPCR, and oxidative stress markers (SOD, CAT, GSH-PX, MDA) in brain tissues were measured with biochemical assays. Results: DSS identified a total of 1,625 bloodstream metabolites, predominantly Benzene derivatives, Carboxylic acids, and Fatty Acyls. DSS significantly improved learning and spatial memory in AD rats and ameliorated cerebral tissue pathology. The formulation enriched the probiotic Ligilactobacillus, modulating metabolites like Ophthalmic acid (OA), Phosphocreatine (PCr), Azacridone A, Inosine, and NAD. DSS regulated Purine and Nicotinate-nicotinamide metabolism, restoring balance in the Candidatus Saccharibacteria-OA interplay and stabilizing gut microbiota-metabolite homeostasis. Additionally, DSS reduced hippocampal IL-1β, IL-6, TNF-α expression, attenuating the inflammatory state. It elevated antioxidative enzymes (SOD, CAT, GSH-PX) while reducing MDA levels, indicating diminished oxidative stress in AD rat brains. Conclusion: DSS addresses AD pathology through multifaceted mechanisms, encompassing gut microbiome regulation, specific metabolite modulation, and the mitigation of inflammation and oxidative stress within the brain. This holistic intervention through the Microbial-Gut-Brain Axis (MGBA) underscores DSS's potential as an integrative therapeutic agent in combatting AD.

Intestinal flora study reveals the mechanism of Danggui Shaoyao San and its decomposed recipes to improve cognitive dysfunction in the rat model of Alzheimer's disease

Background

Alzheimer's disease (AD), characterized by a severe decline in cognitive function, significantly impacts patients' quality of life. Traditional Chinese Medicine (TCM) presents notable advantages in AD treatment, closely linked to its regulation of intestinal flora. Nevertheless, a comprehensive exploration of the precise role of intestinal flora in AD remains lacking.

Methods

We induced an AD model through bilateral intracerebroventricular injection of streptozotocin in rats. We divided 36 rats randomly into 6 groups: sham-operated, model, Danggui Shaoyao San (DSS), and 3 DSS decomposed recipes groups. Cognitive abilities were assessed using water maze and open field experiments. Nissl staining examined hippocampal neuron integrity. Western blot analysis determined synaptoprotein expression. Additionally, 16S rDNA high-throughput sequencing analyzed intestinal flora composition.

Results

DSS and its decomposed recipe groups demonstrated improved learning and memory in rats (P<0.01). The open field test indicated increased central zone residence time and locomotor activity distance in these groups (P<0.05). Furthermore, the DSS and decomposed recipe groups exhibited reduced hippocampal neuronal damage and increased expression levels of synapsin I (P<0.05) and PSD95 (P<0.01) proteins. Alpha and Beta diversity analyses showed that the intestinal flora species richness and diversity in the DSS and decomposed recipe groups were similar to those in the sham-operated group, signifying a significant restorative effect (P<0.05).

Conclusion

The combination of DSS and its decomposed recipes can reduce the abundance of harmful gut microbiota, leading to improvements in cognitive and learning abilities.