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Increasing evidence suggests that the gut microbiota may represent potential strategies for Parkinson's disease (PD) treatment. Our previous research revealed a decreased abundance of Akkermansia muciniphila (Akk) in PD mice; however, whether Akk is beneficial to PD is unknown. To answer this question, the mice received MPTP intraperitoneally to construct a subacute model of PD and were then supplemented with Akk orally for 21 consecutive days. Motor function, dopaminergic neurons, neuroinflammation, and neurogenesis were examined. In addition, intestinal inflammation, and serum and fecal short-chain fatty acids (SCFAs) analyses, were assessed. We found that Akk treatment effectively inhibited the reduction of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and partially improved the motor function in PD mice. Additionally, Akk markedly alleviated neuroinflammation in the striatum and hippocampus and promoted hippocampal neurogenesis. It also decreased the level of colon inflammation. Furthermore, these aforementioned changes are mainly accompanied by alterations in serum and fecal isovaleric acid levels, and lower intestinal permeability. Our research strongly suggests that Akk is a potential neuroprotective agent for PD therapy. [ABSTRACT FROM AUTHOR]

Observational studies have shown abnormal changes in trimethylamine N-oxide (TMAO) levels in the peripheral circulatory system of Parkinson's disease (PD) patients. TMAO is a gut microbiota metabolite that can cross the blood–brain barrier and is strongly related to neuroinflammation. Neuroinflammation is one of the pathological drivers of PD. Herein, we investigated the effect of TMAO on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD model mice. TMAO pretreatment was given by adding 1.5% (w/v) TMAO to the drinking water of the mice for 21 days; then, the mice were administered MPTP (20 mg/kg, i.p.) four times a day to construct an acute PD model. Their serum TMAO concentrations, motor function, dopaminergic network integrity, and neuroinflammation were then assayed. The results showed that TMAO partly aggravated the motor dysfunction of the PD mice. Although TMAO had no effect on the dopaminergic neurons, TH protein content, and striatal DA level in the PD mice, it significantly reduced the striatal 5-HT levels and aggravated the metabolism of DA and 5-HT. Meanwhile, TMAO significantly activated glial cells in the striatum and the hippocampi of the PD mice and promoted the release of inflammatory cytokines in the hippocampus. In summary, higher-circulating TMAO had adverse effects on the motor capacity, striatum neurotransmitters, and striatal and hippocampal neuroinflammation in PD mice. [ABSTRACT FROM AUTHOR]

Neuroinflammation is one of the hallmarks of Parkinson's disease, including the massive activation of microglia and astrocytes and the release of inflammatory factors. Receptor-interacting protein kinase 1 (RIPK1) is reported to mediate cell death and inflammatory signaling, and is markedly elevated in the brain in PD mouse models. Here, we aim to explore the role of RIPK1 in regulating the neuroinflammation of PD. C57BL/6J mice were intraperitoneally injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 20 mg/kg four times/day), followed by necrostatin-1 treatment (Nec-1, RIPK1 inhibitor; 1.65 mg/kg once daily for seven days. Notably, the first Nec-1 was given 12 h before MPTP modeling). Behavioral tests indicated that inhibition of RIPK1 greatly relieved motor dysfunction and anxiety-like behaviors of PD mice. It also increased striatal TH expression, rescue the loss of dopaminergic neurons, and reduce activation of astrocytes in the striatum of PD mice. Furthermore, inhibition of RIPK1 expression reduced A1 astrocytes' relative gene expression (CFB, H2-T23) and inflammatory cytokine or chemokine production (CCL2, TNF-α, IL-1β) in the striatum of PD mice. Collectively, inhibition of RIPK1 expression can provide neuroprotection to PD mice, probably through inhibition of the astrocyte A1 phenotype, and thus RIPK1 might be an important target in PD treatment. [ABSTRACT FROM AUTHOR]

Objectives: Glucocerebrosidase (GBA) gene may be a risk factor for dementia with Lewy bodies (DLB). However, due to the small number of existing studies and the small sample size of previous investigations, it is necessary to conduct objective and quantitative analyses of the association between GBA variants and DLB. There is no consensus regarding the relationship between GBA and the clinical characteristics of DLB. Therefore, we conducted multiple systematic reviews and meta-analyses with a particular focus on the age of onset, sex, and cognitive impairment.Methods: PubMed, Cochrane, and EMBASE databases were searched to retrieve related studies. The odds ratios and 95% confidence interval were calculated to determine the association between GBA and DLB and between GBA and the clinical characteristics of DLB.Results: Our meta-analysis confirmed that the GBA variant rate was significantly higher in the DLB group than in the control group, as were the variant rates of L444P, N370S, and E326K, whereas the variant rate of T369M showed no significant difference between the groups. Furthermore, the relevant literature was summarised again for meta-analyses. The GBA variant group had a younger age of onset and lower Montreal Cognitive Assessment score than the GBA non-variant group in DLB patients. GBA variants do not differ between sexes in DLB patients.Conclusions: GBA variants increased the risk of DLB, especially N370S, E326K, and L444P which are strongly associated with DLB, but T369M was not. Patients harbouring GBA variants have an earlier age of onset, more severe cognitive impairment, and rapid symptom progression; however, sex is irrelevant in DLB. [ABSTRACT FROM AUTHOR]

This study aimed to explore the N6-methyladenosine (m6A) modification genes involved in the pathogenesis of Parkinson's disease (PD) through data analysis of the two data sets GSE120306 and GSE22491 in the GEO database and further explore its influence on cell phenotype in PD. We analyzed the differentially expressed genes and function enrichment analysis of the two sets of data and found that the expression of the m6A-modification gene HNRNPC was significantly downregulated in the PD group, and it played an important role in DNA metabolism, RNA metabolism, and RNA processing and may be involved in PD. Then, we constructed the HNRNPC differential expression cell line to study the role of this gene in the pathogenesis of PD. The results showed that overexpression of HNRNPC can promote the proliferation of PC12 cells, inhibit their apoptosis, and inhibit the expression of inflammatory factors IFN-β, IL-6, and TNF-α, suggesting that HNRNPC may cause PD by inhibiting the proliferation of dopaminergic nerve cells, promoting their apoptosis, and causing immune inflammation. Our study also has certain limitations. For example, the data of the experimental group and the validation group come from different cell types, and the data of the experimental group involve individuals with G2019S LRRK2 mutations. In addition, due to the low expression of HNRNPC in PC12 cells, we used the method of overexpressing this gene to study its function. All these factors may cause our conclusions to be biased. Therefore, more research is still needed to corroborate it in the future. [ABSTRACT FROM AUTHOR]

Purpose. This study aimed to explore new core genes related to the occurrence of Parkinson's disease (PD) and core genes that can lead to the progression of PD. Methods. The expression profile data of GSE42966, which contained six substantia nigra tissues isolated from normal individuals and nine substantia nigra tissues isolated from patients with PD, were obtained from Gene Expression Omnibus. Differentially expressed genes (DEGs) were identified, followed by functional enrichment analysis and protein-protein interaction (PPI) network construction. We then identified 10 hub genes and analyzed their expression in different Braak stages. Results. A total of 773 DEGs were identified that were significantly enriched in metabolic pathways. Ten hub genes were identified through the PPI network, namely, GNG3, MAPK1, FPR1, ATP5B, GNG2, PRKACA, HRAS, HSPA8, PSAP, and GABBR2. The expression of HRAS was different in patients with PD with Braak stages 3 and 4. Conclusion. These 10 hub genes and the metabolic pathways they are enriched in may be involved in the pathogenesis of PD. HRAS may have potential value in predicting the progression of PD. [ABSTRACT FROM AUTHOR]

• AHR activation was decreased in the TH+ neurons after MPTP treatment. • AHR activation was increased in IBA1-positive microglia after MPTP treatment. • AHR activation was increased in GFAP-positive astrocytes after MPTP treatment. Aryl Hydrocarbon Receptor (AHR) is a ligand-activated transcription factor expressed in various brain regions. However, little is known about the role of AHR during neuroinflammation in the 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine (MPTP)-induced Parkinson's disease (PD) mouse model. Here, mice were sacrificed at day 4, day 6 and day 8 respectively after MPTP or saline treatment. Behavioral tests, Tyrosine hydroxylase (TH) expression, glial reaction, and AHR expression and activation were then assayed. As expected, mice treated with MPTP showed apparent behavioral dysfunctions and significantly reduced TH content. Immunofluorescence (IF) labeling showed an increased trend of phosphorylated AHR activation in the Substantia Nigra pars compacta (SNpc) and striatum after MPTP treatment. Western blot analysis demonstrated that MPTP treatment induced a significantly increased level of AHR at each time point tested, with the highest level observed at day 6 in the striatum. To determine exactly the AHR activation in relation to changes of glial cell reactivity, double IF labeling was performed for either IBA1 (microglia marker) and p-AHR, or GFAP (astrocyte marker) and p-AHR. The results demonstrated that MPTP treatment not only increases the number of p-AHR-positive IBA1-expressing cells in the striatum and the SNpc, but also increases that of p-AHR-positive GFAP-expressing cells in the striatum. Intriguingly, the increase of the number of cells co-expressing both p-AHR and IBA1 was highest at day 4 in response to MPTP in the striatum and at day 8 in the SNpc. The number of cells co-expressing both p-AHR and GFAP was increased at days 4, 6 and 8 in the striatum. In conclusion, our study suggests that AHR activation may facilitate PD diagnosis and serve as a target for the treatment of PD. [ABSTRACT FROM AUTHOR]

Parkinson's disease is normally accompanied by excessive inflammation. Myocardial infraction associated transcript 2 (Mirt2) has an activity to relieve inflammation in numerous cell types. Here, we aimed to investigate whether Mirt2 could elevate the resistance of SH-Sy5y cells to inflammation. Tumor necrosis factor alpha (TNF-α) was used to induce inflammation in SH-Sy5y cells. Mirt2 overexpressed or silenced cells were established. MicroRNA-101 (miR-101) mimic was used to up-regulate miR-101. Viable and apoptotic cells as well as reactive oxidative species (ROS) were detected after staining. Proteins associated with apoptosis, interleukin (IL) and signaling regulators were evaluated by Western blot. IL secretion was assessed by ELISA. Mirt2 and miR-101 were determined by qRT-PCR. We discovered that TNF-α weakened viability of SH-Sy5y cells and resulted in sensitivity to apoptosis with cleavage of PARP and caspase-3. Expression and secretion of IL-6 as well as generation of ROS were facilitated by TNF-α. However, Mirt2 overexpression moderated TNF-α-caused apoptosis associated with inflammation and oxidative stress. Mirt2 suppressed TNF-α-induced accumulation of miR-101, and based on this Mirt2 exhibited anti-inflammatory roles. Additionally, TNF-α-triggered phosphorylation of regulators was blocked by Mirt2 while restored by miR-101 mimic. In short Mirt2 overexpression exhibited anti-inflammatory properties through miR-101 suppression. Through down-regulating miR-101, Mirt2 blocked TNF-α-triggered NF-κB/p38MAPK pathway. • Mirt2 up-regulation exhibits an anti-inflammatory capacity in SH-Sy5y cells. • Inhibition of inflammation is attributable to Mirt2-elicited miR-101 repression. • Mirt2 blunts NF-κB and p38MAPK cascades via down-regulating miR-101. [ABSTRACT FROM AUTHOR]