Association of VEGF gene polymorphisms with sporadic Parkinson's disease in Chinese Han population

The VEGFs/VEGFRs system in Alzheimer's and Parkinson's diseases: Pathophysiological roles and therapeutic implications

The vascular endothelial growth factors (VEGFs) and their cognate receptors (VEGFRs), besides their well-known involvement in physiological angiogenesis/lymphangiogenesis and in diseases associated to pathological vessel formation, play multifaceted functions in the central nervous system (CNS). In addition to shaping brain development, by controlling cerebral vasculogenesis and regulating neurogenesis as well as astrocyte differentiation, the VEGFs/VEGFRs axis exerts essential functions in the adult brain both in physiological and pathological contexts. In this article, after describing the physiological VEGFs/VEGFRs functions in the CNS, we focus on the VEGFs/VEGFRs involvement in neurodegenerative diseases by reviewing the current literature on the rather complex VEGFs/VEGFRs contribution to the pathogenic mechanisms of Alzheimer's (AD) and Parkinson's (PD) diseases. Thereafter, based on the outcome of VEGFs/VEGFRs targeting in animal models of AD and PD, we discuss the factual relevance of pharmacological VEGFs/VEGFRs modulation as a novel and potential disease-modifying approach for these neurodegenerative pathologies. Specific VEGFRs targeting, aimed at selective VEGFR-1 inhibition, while preserving VEGFR-2 signal transduction, appears as a promising strategy to hit the molecular mechanisms underlying AD pathology. Moreover, therapeutic VEGFs-based approaches can be proposed for PD treatment, with the aim of fine-tuning their brain levels to amplify neurotrophic/neuroprotective effects while limiting an excessive impact on vascular permeability.

A proteogenomic view of Parkinson's disease causality and heterogeneity

The pathogenesis and clinical heterogeneity of Parkinson's disease (PD) have been evaluated from molecular, pathophysiological, and clinical perspectives. High-throughput proteomic analysis of cerebrospinal fluid (CSF) opened new opportunities for scrutinizing this heterogeneity. To date, this is the most comprehensive CSF-based proteomics profiling study in PD with 569 patients (350 idiopathic patients, 65 GBA + mutation carriers and 154 LRRK2 + mutation carriers), 534 controls, and 4135 proteins analyzed. Combining CSF aptamer-based proteomics with genetics we determined protein quantitative trait loci (pQTLs). Analyses of pQTLs together with summary statistics from the largest PD genome wide association study (GWAS) identified 68 potential causal proteins by Mendelian randomization. The top causal protein, GPNMB, was previously reported to be upregulated in the substantia nigra of PD patients. We also compared the CSF proteomes of patients and controls. Proteome differences between GBA + patients and unaffected GBA + controls suggest degeneration of dopaminergic neurons, altered dopamine metabolism and increased brain inflammation. In the LRRK2 + subcohort we found dysregulated lysosomal degradation, altered alpha-synuclein processing, and neurotransmission. Proteome differences between idiopathic patients and controls suggest increased neuroinflammation, mitochondrial dysfunction/oxidative stress, altered iron metabolism and potential neuroprotection mediated by vasoactive substances. Finally, we used proteomic data to stratify idiopathic patients into "endotypes". The identified endotypes show differences in cognitive and motor disease progression based on previously reported protein-based risk scores.Our findings not only contribute to the identification of new therapeutic targets but also to shape personalized medicine in CNS neurodegeneration.

Association of ATG5 gene polymorphism with Parkinson's disease in a Han Chinese population

Purpose

There is growing evidence that autophagy-related gene 5 (ATG5) is involved in neural development, neuronal differentiation, and neurodegenerative diseases. The purpose of this study was to investigate the association between ATG5 gene single-nucleotide polymorphisms (SNPs) and Parkinson’s disease (PD) in the Han population.

Methods

A case–control study was conducted in 120 PD patients and 100 healthy volunteers. MassArray platform was used to analyze polymorphisms in three different regions of ATG5 gene (rs510432, rs573775 and rs17587319). In the included subjects, 50 PD patients and 50 healthy volunteers were selected, and the plasma ATG5 concentration was detected by enzyme-linked immunosorbent assay (ELISA). The allele and genotype frequencies of SNPs were assessed using the SHEsis program.

Results

We found a significant correlation between rs17587319 and PD, and the subcomponent showed a high correlation between rs17587319 with cognitive impairment and age at onset in PD patients. At the same time, the total plasma ATG5 level of PD patients and the plasma ATG5 expression level of early-onset Parkinson’s disease (EOPD) patients were significantly higher than the control group, while there was no significant difference of ATG5 expression between late-onset Parkinson’s disease (LOPD) patients and the control group.

Conclusion

These findings suggest that genetic variations in the ATG5 gene and low levels of the ATG5 protein are associated with susceptibility to PD and with cognitive impairment in PD patients. ATG5 could be a potential biomarker to assess the severity and prognosis of PD.

Arterial Blood Pressure Variability and Other Vascular Factors Contribution to the Cognitive Decline in Parkinson's Disease

Dementia is one of the most disabling non-motor symptoms in Parkinson’s disease (PD). Unlike in Alzheimer’s disease, the vascular pathology in PD is less documented. Due to the uncertain role of commonly investigated metabolic or vascular factors, e.g., hypertension or diabetes, other factors corresponding to PD dementia have been proposed. Associated dysautonomia and dopaminergic treatment seem to have an impact on diurnal blood pressure (BP) variability, which may presumably contribute to white matter hyperintensities (WMH) development and cognitive decline. We aim to review possible vascular and metabolic factors: Renin-angiotensin-aldosterone system, vascular endothelial growth factor (VEGF), hyperhomocysteinemia (HHcy), as well as the dopaminergic treatment, in the etiopathogenesis of PD dementia. Additionally, we focus on the role of polymorphisms within the genes for catechol-O-methyltransferase (COMT), apolipoprotein E (APOE), vascular endothelial growth factor (VEGF), and for renin-angiotensin-aldosterone system components, and their contribution to cognitive decline in PD. Determining vascular risk factors and their contribution to the cognitive impairment in PD may result in screening, as well as preventive measures.

Interaction between SNCA gene polymorphisms and T2DM with Parkinson's disease

AIMS

To investigate the association of several single nucleotide polymorphisms (SNPs) within alpha-synuclein (SNCA) gene and additional gene-environment interaction with Parkinson's disease (PD) risk.

METHODS

Hardy-Weinberg equilibrium (HWE) is tested for controls using SNPstats (http://bioinfo.iconcologia.net/SNPstats). Logistic regression is used to calculate the ORs (95% CI) for relations between the four SNPs and PD risk. The generalized multifactor dimensionality reduction (GMDR) model is used to evaluate the synergy between gene and environment.

RESULTS

A total of 1161 people were included in this study, including 386 cases of PD and 775 normal controls. In this study, the genotype frequency of the control group was consistent with HWE distribution. Rs356219-G allele frequency was 30.0% in patients and 19.8% in control group. The rs356221-T allele frequency was 29.7% in the patients and 20.8% in the control group. Rs356219-G and rs356221-T alleles were associated with increased PD risk, with adjusted ORs (95% CI) of 1.92 (1.28-2.52) and 1.52 (1.05-2.02), respectively. We also found no significant correlation between rs2301134 and rs2301135 and susceptibility to PD. The best gene-environment interaction models were determined by GMDR analysis, which shown a significant gene-T2DM interaction combinations, but the gene-alcohol drinking interaction combinations were all not significant. We also conducted stratified analysis for interaction effect using logistic regression. We found that T2DM patients with rs356221-AT/ TT genotype have the highest PD risk, compared to subjects with rs356219-AA genotype, OR (95%CI) = 2.67 (1.83-3.46).

CONCLUSIONS

The rs356219-G and rs356221-T, gene-environment interaction between rs356221 and T2DM were all associated with increased PD risk.

PTPRC Expression in Blood is Downregulated in Parkinson's and Progressive Supranuclear Palsy Disorders

BACKGROUND

Parkinson's disease (PD) shares pathological and clinical features with progressive supranuclear palsy (PSP) patients making the diagnosis challenging. Distinguishing PD from PSP is crucial given differences in disease course, treatment and clinical management.

OBJECTIVE

Although some progress has been made in the discovery of biomarkers for PD and PSP, there is an urgent need to identify additional biomarkers capable of distinguishing between these diseases.

METHODS

In this study, we tested the phosphatases DUSP8 and PTPRC for their diagnostic potential using quantitative PCR assays, in blood of 138 samples from participants nested in the Parkinson's Disease Biomarkers Program.

RESULTS

Relative abundance of PTPRC mRNA was downregulated in PSP patients compared to PD and healthy controls, whereas there was no significant difference in the expression of DUSP8. Interestingly, PTPRC mRNA correlated with the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) total score and MDS-UPDRS- part III, thus indicating it might be useful as part of a biosignature to stratify patients according to disease severity and progression.

CONCLUSIONS

Collectively, these results suggest that PTPRC expression may be useful for distinguishing PD from PSP patients as part of a biosignature. Evaluation of PTPRC along with additional biomarkers in a larger and well-characterized longitudinal study is warranted.

Long-Term Intravitreal Ranibizumab as a Potential Additional Risk Factor for Neurodegeneration in Parkinson's Disease: A Case Report

In November 2012, a 72-year old patient was diagnosed with left eye wet age-related macular degeneration. The patient received three monthly intravitreal injections of ranibizumab, with complete resolution of retinal hemorrhage and edema and reinstatement of visual acuity. In May 2015, symptomatic relapse was detected. The patient was again treated with intravitreal ranibizumab, with overall six injections till the end of February 2016. In May 2016, the patient complained of left hand resting tremor, bradykinesia, and postural rigidity of head and trunk. A diagnosis of clinically established PD was made based on new criteria of the Movement Disorders Society. Single Photon Emission Computerized Tomography of the Dopamine Transporter with (123I) ioflupane documented a low Dopamine Transporter (DAT) uptake mostly in the right striatum. Due to the documented protective role of vascular endothelial growth factor (VEGF) on the dopaminergic neurons, intensive intravitreal injections of the anti-VEGF agent ranibizumab may have played as an additional risk factor accelerating the neurodegeneration process related to PD and the onset of the related clinical signs and symptoms.

The Importance of VEGF-KDR Signaling Pathway Genes should Not Be Ignored When the Risk of Developing Multiple Sclerosis is Taken into Consideration

Vascular endothelial growth factor (VEGF) and its receptor kinase insert domain-containing receptor (KDR) pathway trigger the process of angiogenesis as well as inflammation, which contributes to the development and progression of demyelinating lesions in multiple sclerosis. This work is a case-control study comprising of a total of 400 subjects with multiple sclerosis and 400 healthy controls. Participants were subjected to neurological examination and peripheral blood sampling for genotyping. Polymorphisms in the VEGF and KDR genes were assessed using the restriction fragment length polymorphism (RFLP-PCR) method. A significantly higher frequency of the T allele and TT genotype of the VEGF 936C > T (rs3025039) polymorphism was found in the multiple sclerosis group than in the healthy control group (P = 0.01 [OR = 1.41] and P = 0.01 [OR = 3.12], respectively). In addition, VEGF 936C  >  T showed an association with patients in a recessive model. However, the KDR -604T > C (rs2071559) polymorphism showed no significant difference in either allelic or genotype frequency between the two groups. Taken together, the results of the present study suggests that the T allele of the rs3025039 in VEGF gene could be considered a risk factor for developing multiple sclerosis in the Iranian population.