The Role of Immune Dysfunction in Parkinson's Disease Development

Association of worrier trait with the risk of Parkinson's disease: a longitudinal study based on 457,180 UK Biobank participants

Objective

To explore the potential association between the trait of being a worrier and the likelihood of developing Parkinson's disease (PD).

Background

While extensive research has explored the link between PD and disorders such as depression and anxiety, limited research has been conducted on the association between worry and PD.

Methods

This prospective cohort study utilized data obtained from the UK Biobank, with baseline assessments conducted between 2006 and 2010 and follow-up until July 16, 2023. Multivariable Cox proportional hazards regression analysis was carried out to evaluate the link between worrier trait and the development of PD. Adjustments were made for demographic factors, smoking, PD polygenetic risk scores, alcohol consumption, body mass index, physical activity, stroke, diabetes, hypertension, heart attack, and psychiatric history. Subgroup and sensitivity analyses were additionally conducted to validate the reliability of the outcomes.

Results

Over a mean follow-up period of 13.5 years, 3123 participants (0.68%) out of 457,180 participants [median (IQR) age, 58.00 (50.00, 63.00) years; 54.3% female] developed PD. The incidence of PD was positively linked to worry (log-rank test, P < 0.001). Furthermore, worriers demonstrated a heightened risk of developing PD [hazard ratio (HR) 1.32, 95% CI 1.23-1.42]. Importantly, this link persisted even following adjustments for covariates (fully adjusted model HR 1.27, 95% CI 1.18-1.37). Additionally, when cases within the initial 5 years of follow-up were excluded, the significance of the association persisted (HR: 1.28, 95% CI 1.18-1.38). In subgroup analyses categorized by age, early-onset PD (age < 60 years) showed a stronger association than late-onset PD (age ≥ 60 years; early-onset PD HR 1.32, 95% CI 0.86-2.03; late-onset PD HR 1.13, 95% CI 1.05-1.22).

Conclusion

These findings suggest that the worrier trait is consistently associated with a higher risk of developing PD, particularly among young individuals, highlighting the importance of mental wellness.

Immune Cell Distributions in the Blood of Healthy Individuals at High Genetic Risk of Parkinson's Disease

The immune system likely plays a key role in Parkinson's disease (PD) pathophysiology. Thus, we investigated whether immune cell compositions are already altered in healthy individuals at high genetic risk for PD. We quantified 92 immune cell subtypes in the blood of 442 individuals using multicolor flow cytometry. Polygenic risk scores (PGS) for PD were calculated based on genome-wide significant SNPs (n = 87) from a large genome-wide association study (n = 1,530,403). Linear regression analyses did not reveal significant associations between PGS and any immune cell subtype (FDR = 0.05). Nominally significant associations were observed for NKG2C+ B cells (p = 0.026) in the overall sample. Older participants at increased genetic PD risk also showed a higher proportion of myeloid dendritic cells (p = 0.019) and CD27+CD4+ memory T cells (p = 0.043). Several immune cells were nominally statistically associated in women only. These findings suggest that major alterations of immune cells only occur later in the progression of PD.

Stimulation of microneedles alleviates pathology of Parkinson's disease in mice by regulating the CD4+/CD8+ cells from the periphery to the brain

Introduction

Immune dysfunction is a major cause of neuroinflammation and accelerates the progression of Parkinson's disease (PD). Numerous studies have shown that stimulation of specific acupuncture points (acupoints) can ameliorate PD symptoms. The purpose of this study was to investigate whether attaching microneedles to acupoints would improve PD pathology by recovering immune dysfunction.

Methods

The PD mouse model was induced by intrastriatal injection of 6-hydroxydopamine (6-OHDA), and microneedle patches (MPs) or sham patches (SPs) were attached to GB20 and GB34, representative acupoints for treating PD for 14 days.

Results

First, the behavioral experiment showed that motor disorders induced by 6-OHDA were significantly improved by MP. Simultaneously, 6-OHDA-induced dopaminergic neuronal death and brain neuroinflammation decreased. Conversely, SP had no effect on behavioral disorders, neuronal death, or neuroinflammation. Measurement results from flow cytometry of immune cells in the brain and blood revealed a disruption in the CD4+/CD8+ ratio in the 6-OHDA group, which was significantly restored in the MP group. The brain mRNA expression of cytokines was significantly increased in the 6-OHDA group, which was significantly decreased by MP.

Discussion

Overall, our results suggest that the attachment of MPs to GB20 and GB34 is a new method to effectively improve the pathology of PD by restoring peripheral and brain immune function.

Utilizing Machine Learning to Identify Biomarkers of Endoplasmic Reticulum Stress and Analyze Immune Cell Infiltration in Parkinson's Disease

The neurodegenerative disorder known as Parkinson's disease (PD) affects many people. The objective of this investigation was to examine the relationship between immune system infiltration, ATP-binding cassette transporter subfamily A member 7 (ABCA7) and TBL2 as well as potential therapeutic targets for the identification of PD associated to endoplasmic reticulum (ER) stress. First, we obtained PD data through GEO and divided it into two sets: a training set (GSE8397) plus a set for validation (GSE7621). Functional enrichment analysis was performed on a set of DEGs that overlapped with genes involved in endoplasmic reticulum stress. To identify genes of PD linked with endoplasmic reticulum stress, we employed random forest (RF) along with the least absolute shrinkage and selection operator (LASSO) logistic regression. Spearman's rank correlation analysis was then used to find associations among diagnostic markers with immune cell penetration. A grand total of 2 stress-related endoplasmic reticulum signature transcripts were identified. ABCA7 and TBL2 were shown to have diagnostic potential for PD and immune infiltrating cells have a role in the etiology of the disease. Additionally, resting CD4 memory, plasma cells, and NK cells overall exhibited positive associations with ABCA7, whereas triggered macrophages, T cells with active CD4 memory, activating NK cells, T cells with activated CD4 naive, engaged NK cells, and neutrophils all had adverse interactions with ABCA7. Overall, ABCA7 together with TBL2 have diagnostic utility for PD, and several types of immune cells, especially macrophages, may be involved in the development and progression of the disease.

The role of inflammation in neurological disorders: a brief overview of multiple sclerosis, Alzheimer's, and Parkinson's disease'

Neuroinflammation is a central feature in the pathophysiology of several neurodegenerative diseases, including MS, AD, and PD. This review aims to synthesize current research on the role of inflammation in these conditions, emphasizing the potential of inflammatory biomarkers for diagnosis and treatment. We highlight recent findings on the mechanisms of neuroinflammation, the utility of biomarkers in disease differentiation, and the implications for therapeutic strategies. Advances in understanding inflammatory pathways offer promising avenues for developing targeted interventions to improve patient outcomes. Future research should focus on validating these biomarkers in larger cohorts and integrating them into clinical practice to enhance diagnostic accuracy and therapeutic efficacy.