Exploring the Neuroprotective Mechanism of Curcumin Inhibition of Intestinal Inflammation against Parkinson's Disease Based on the Gut-Brain Axis

Sika Deer Velvet Antler Peptide Exerts Neuroprotective Effect in a Parkinson's Disease Model via Regulating Oxidative Damage and Gut Microbiota

Parkinson's disease (PD) is the second most common neurodegenerative disorder globally. Recognizing the potential of velvet antler in the nervous system, as shown in numerous studies, this research was aimed at evaluating the neuroprotective effects of Sika Deer velvet antler peptide (VAP), along with the underlying mechanisms in neurotoxin-induced PD models. Initially, a peptidomic analysis of the VAP, which comprised 189 varieties of peptides, was conducted using LC-MS. Nine sequences were identified as significant using Proteome Discoverer 2.5 software. In a cellular model of PD, where PC12 cells are treated with the neurotoxin 1-methyl-4-phenylpyridinium (MPP+), the administration of the VAP reduced the cell damage and apoptosis induced by MPP+. This protective effect was associated with a decrease in oxidative stress. This protective mechanism was found to be mediated through the activation of the SIRT1-dependent Akt/Nrf2/HO-1-signaling pathway. In animal models, specifically in mice with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD, the administration of the VAP effectively reduced the dopaminergic neuron damage and reversed the neurobehavioral deficits. They also diminished microglia activation and apoptosis, all without any noticeable adverse effects. Additionally, the VAP was observed to beneficially alter the gut microbiota, as marked by an increase in the abundances of Prevotellaceae, Helicobacteraceae, and Prevotella. These findings suggest that VAP exerts its neuroprotective effect against neurodegeneration by inhibiting oxidative stress and modulating gut microbiota.

Integrating Network Pharmacology, Transcriptomics to Reveal Neuroprotective of Curcumin Activate PI3K / AKT Pathway in Parkinson's Disease

Background

Parkinson's disease (PD) is the most prevalent movement disorder. Curcumin, a polyphenol with hydrophobic properties, has been proved against Parkinson. Our previous study suggested that curcumin's effectiveness in treating Parkinson's disease may be linked to the gut-brain axis, although the specific mechanism by which curcumin exerts neuroprotective effects in the brain remains unknown.

Methods

The therapeutic efficacy of curcumin was evaluated using behavioral tests, immunofluorescence of tyrosine hydroxylase (TH). Network pharmacology and transcriptomics predicted the mechanisms of curcumin in PD. Activation of the phosphatidylinositol 3-kinase PI3K/AKT pathway was confirmed by quantitative polymerase chain reaction (qPCR) and immunofluorescence.

Results

Curcumin restored the dyskinesia and dopaminergic neurons damage of MPTP-induced mice. Curcumin against Parkinson's disease by regulating inflammation, oxidative stress, and aging. The mechanisms of these were associated with activation of PI3K / AKT pathway.

Conclusion

In conclusion, the neuroprotective mechanisms of curcumin activate PI3K / AKT pathway in Parkinson's disease was revealed by our study.

[The complex effect of polyphenols on the gut microbiota and triggers of neurodegeneration in Parkinson's disease]

Intestinal dysfunction and microbiome changes are actively discussed in the modern literature as the most important link in the development of neurodegenerative changes in Parkinson's disease. The article discusses the pathogenetic chain «microbiome- intestine-brain», as well as factors that affect the development of intestinal dysbiosis. A promising direction for influencing microflora and inflammatory changes in the intestine is the use of polyphenols, primarily curcumin. The review of experimental, laboratory, clinical research proving the pleiotropic effect of curcumin, including its antioxidant, anti-inflammatory, neuroprotective effects, realized both through peripheral and central mechanisms is presented.

Curcumin alleviates 1-methyl- 4-phenyl- 1,2,3,6-tetrahydropyridine- induced Parkinson's disease in mice via modulating gut microbiota and short-chain fatty acids

Background: The microbiota-gut-brain axis has been proposed as a potential therapeutic target of PD. The effects of curcumin against Parkinson's disease have been demonstrated; however, its neuroprotective mechanisms remain unknown. Our study investigated the potential mechanisms through which curcumin ameliorates Parkinson's disease via the microbiota-gut-brain axis. Methods: Mice were randomly divided into four groups: control, Curcumin, MPTP, and MPTP + Curcumin. Motor deficits and gastrointestinal dysfunction were assessed using behavioral test, intestinal motility test, and fecal parameter measurement. The loss of dopaminergic neurons and intestinal barrier function was measured using Western blot and immunofluorescence. Shotgun metagenomic sequencing and LC-MS were parallelly performed on mice feces to investigate alterations in microbiota and metabolites. Results: Curcumin alleviated motor deficits and the loss of dopaminergic neurons in MPTP-induced mice. Curcumin ameliorated gastrointestinal and intestinal barrier dysfunctions in MPTP-induced mice. Curcumin reduced gut microbial dysbiosis and modulated carbohydrate metabolism in MPTP-induced mice. Curcumin restored short-chain fatty acid (SCFA) profiles in MPTP-induced mice. Conclusion: Concurrently, these results indicate that curcumin inhibits Parkinson's disease by regulating the gut microbiota and short-chain fatty acids.

δ-Opioid Receptor Activation Inhibits Ferroptosis by Activating the Nrf2 Pathway in MPTP-Induced Parkinson Disease Models

Introduction

Recent studies suggest the involvement of ferroptosis in the pathogenesis of Parkinson disease (PD). δ-Opioid receptors (DORs) have neuroprotective effects in PD. It is not known whether the neuroprotective effects of DORs in PD are attributable to the inhibition of ferroptosis. Therefore, we aimed to investigate the role of DORs in ferroptosis in MPTP-induced PD models.

Methods

To identify the influence of DORs on ferroptosis in MPTP-induced PD models, we measured the malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) levels, analyzed the levels of ferroptosis-related proteins (GXP4 and SLC7a11) and Nrf2 expression by using western blotting, and assessed mitochondrial dysfunction by using JC-1 staining and transmission electron microscopy.

Results

DOR activation reduced the 4-HNE and MDA levels, increased the GXP4 and SLC7a11 levels, and ameliorated mitochondrial dysfunction in MPTP-induced PD models. These neuroprotective effects of DORs could be blocked by Nrf2-siRNA. Thus, the effects of DORs on ferroptosis in PD models were partially controlled by Nrf2, which regulated GXP4 and SLC7a11 synthesis.

Conclusion

DORs exert neuroprotective effects in PD models by inhibiting ferroptosis partially via activating the Nrf2 pathway.