Gender differences in the IL6 -174G>C and ESR2 1730G>A polymorphisms and the risk of Parkinson's disease

Association of IL6 Gene Polymorphisms and Neurological Disorders: Insights from Integrated Bioinformatics and Meta-Analysis

Interleukin 6 (IL6) is an inflammatory biomarker linked to central and peripheral nervous system diseases. This study combined bioinformatics and statistical meta-analysis to explore potential associations between IL6 gene variants (rs1800795, rs1800796, and rs1800797) and neurological disorders (NDs) and brain cancer. The meta-analysis was conducted on substantial case-control datasets and revealed a significant correlation between IL6 SNPs (rs1800795 and rs1800796) with overall NDs (p-value < 0.05). The disease-stratified analysis of rs1800795 revealed significant correlations with Schizophrenia, Alzheimer's, and Parkinson's diseases (p-value < 0.05), while rs1800796 showed a substantial connection with Celiac disease (p-value < 0.05). The ethnicity-stratified analysis revealed noteworthy associations between rs1800795 in both Asians and Caucasians (p-value < 0.05), while rs1800796 showed significant associations across all ethnic groups analyzed (p-value < 0.05). Furthermore, integrated Bioinformatics analyses using GTEx and TCGA datasets highlighted IL6's involvement in NDs and its potential role in brain cancer. Specifically, IL6 SNPs (rs1800795 and rs1800797) showed a significant association with Glioma (p-value < 0.001). Copy number alterations and increased IL6 expressions were linked to cancer severity (p-value < 0.001) and hypoxia (p-value < 0.0001). Kaplan-Meier survival analysis demonstrated that elevated IL6 expression was strongly associated with decreased overall survival in brain cancer patients (p-value < 0.0001). In conclusion, this study identified notable correlations between IL6 SNPs and NDs, underscoring their potential as valuable prognostic biomarkers for various neurological conditions.

The role of genetics and gender specific differences in neurodegenerative disorders: Insights from molecular and immune landscape

Neurodegenerative disorders (NDDs) are the most common neurological disorders with high prevalence and have significant socioeconomic implications. Understanding the underlying cellular and molecular mechanisms associated with the immune system can be effective in disease etiology, leading to more effective therapeutic approaches for both females and males. The central nervous system (CNS) actively participates in immune responses, both within and outside the CNS. Immune system activation is a common feature in NDDs. Gender-specific factors play a significant role in the prevalence, progression, and manifestation of NDDs. Neuroinflammation, in both inflammatory neurological and neurodegenerative conditions, is defined by the triggering of microglia and astrocyte cell activation. This results in the secretion of pro-inflammatory cytokines and chemokines. Numerous studies have documented the role of neuroinflammation in neurological diseases, highlighting the involvement of immune signaling pathways in disease development. Converging evidence support immune system involvement during neurodegeneration in NDDs. In this review, we summarize emerging evidence that reveals gender-dependent differences in immune responses related to NDDs. Also, we highlight sex differences in immune responses and discuss how these sex-specific influences can increase the risk of NDDs. Understanding the role of gender-specific factors can aid in developing targeted therapeutic strategies and improving patient outcomes. Ultimately, the better understanding of these mechanisms contributed to sex-dependent immune response in NDDs, can be critically usful in targeting of immune signaling cascades in such disorders. In this regard, sex-related immune responses in NDDs may be promising and effective targets in therapeutic strategies.

Quantitative and causal analysis for inflammatory genes and the risk of Parkinson's disease

Background

The dysfunction of immune system and inflammation contribute to the Parkinson's disease (PD) pathogenesis. Cytokines, oxidative stress, neurotoxin and metabolism associated enzymes participate in neuroinflammation in PD and the genes involved in them have been reported to be associated with the risk of PD. In our study, we performed a quantitative and causal analysis of the relationship between inflammatory genes and PD risk.

Methods

Standard process was performed for quantitative analysis. Allele model (AM) was used as primary outcome analysis and dominant model (DM) and recessive model (RM) were applied to do the secondary analysis. Then, for those genes significantly associated with the risk of PD, we used the published GWAS summary statistics for Mendelian Randomization (MR) to test the causal analysis between them.

Results

We included 36 variants in 18 genes for final pooled analysis. As a result, IL-6 rs1800795, TNF-α rs1799964, PON1 rs854560, CYP2D6 rs3892097, HLA-DRB rs660895, BST1 rs11931532, CCDC62 rs12817488 polymorphisms were associated with the risk of PD statistically with the ORs ranged from 0.66 to 3.19 while variants in IL-1α, IL-1β, IL-10, MnSOD, NFE2L2, CYP2E1, NOS1, NAT2, ABCB1, HFE and MTHFR were not related to the risk of PD. Besides, we observed that increasing ADP-ribosyl cyclase (coded by BST1) had causal effect on higher PD risk (OR[95%CI] =1.16[1.10-1.22]) while PON1(coded by PON1) shown probably protective effect on PD risk (OR[95%CI] =0.81[0.66-0.99]).

Conclusion

Several polymorphisms from inflammatory genes of IL-6, TNF-α, PON1, CYP2D6, HLA-DRB, BST1, CCDC62 were statistically associated with the susceptibility of PD, and with evidence of causal relationships for ADP-ribosyl cyclase and PON1 on PD risk, which may help understand the mechanisms and pathways underlying PD pathogenesis.

Polymorphisms of Interleukin-6 and Interleukin-8 Are Not Associated with Parkinson's Disease in Taiwan

Background: Studies have suggested that cytokines are crucial mediators in the pathogenesis of Parkinson’s disease (PD). The multifunctional cytokine interleukin (IL)-6 and its single nucleotide polymorphisms (SNPs) were found to have an impact on the development of PD. However, different studies in associations of IL-6 genetic variants with PD showed inconsistent results and it has never been explored in a Taiwanese population. Both IL-1α and IL-8 contribute to the same inflammation pathway. IL-1α genetic polymorphism has an effect on late-onset PD in Taiwan, whereas the associations of IL-8 genetic variants with PD in Taiwan remain to be investigated. Methods: This study examined the frequencies of polymorphisms within the critical promoter areas of the proinflammatory cytokine genes: IL-6 G-174C (rs1800795) and IL-8 A-251T (rs4073) in Taiwanese PD patients compared with age-and gender-matched healthy subjects. Comparisons were also made in genotype and allele frequencies of IL-6 G-174C (rs1800795) and IL-8 A-251T (rs4073) among different populations in previous studies. Results: In total, 1120 subjects, including 509 PD patients (female/male: 259/250) and 511 control subjects (female/male: 252/259), were recruited. We found no statistically significant differences in IL-6 G-174C (rs1800795) or IL-8 A-251T (rs4073) genotypic and allelic distribution between PD and controls, even after being stratified by age at onset and gender. Conclusions: The results did not demonstrate any association of IL-6 G-174C (rs1800795) or IL-8 A-251T (rs4073) with PD in a Taiwanese population. Despite the negative results, this is the first study in associations of IL-6 G-174C (rs1800795) and IL-8 A-251T (rs4073) with PD in Taiwan. The relevance of genetic variants of IL-6 G-174C (rs1800795) or IL-8 A-251T (rs4073) on PD susceptibility warrants further investigation.

Assessment of the Telomere Length and Its Effect on the Symptomatology of Parkinson's Disease

Telomeres, which are repetitive sequences that cap the end of the chromosomes, shorten with each cell division. Besides cellular aging, there are several other factors that influence telomere length (TL), in particular, oxidative stress and inflammation, which play an important role in the pathogenesis of neurodegenerative brain diseases including Parkinson’s disease (PD). So far, the majority of studies have not demonstrated a significant difference in TL between PD patients and healthy individuals. However, studies investigating the effect of TL on the symptomatology and disease progression of PD are scarce, and thus, warranted. We analyzed TL of peripheral blood cells in a sample of 204 PD patients without concomitant autoimmune diseases and analyzed its association with several PD related phenotypes. Monochrome multiplex quantitative PCR (mmqPCR) was used to determine relative TL given as a ratio of the amount of DNA between the telomere and albumin as the housekeeping gene. We found a significant difference in the relative TL between PD patients with and without dementia, where shorter TL presented higher risk for dementia (p = 0.024). However, the correlation was not significant after adjustment for clinical factors (p = 0.509). We found no correlations between TLs and the dose of dopaminergic therapy when the analysis was adjusted for genetic variability in inflammatory or oxidative factors. In addition, TL influenced time to onset of motor complications after levodopa treatment initiation (p = 0.0134), but the association did not remain significant after adjustment for age at inclusion and disease duration (p = 0.0781). Based on the results of our study we conclude that TL contributes to certain PD-related phenotypes, although it may not have a major role in directing the course of the disease. Nevertheless, this expends currently limited knowledge regarding the association of the telomere attrition and the disease severity or motor complications in Parkinson’s disease.

Gender Differences and Quality of Life in Parkinson's Disease

Parkinson's disease has been found to significantly affect health-related quality of life. The gender differences of the health-related quality of life of subjects with Parkinson's disease have been observed in a number of studies. These differences have been reported in terms of the age at onset, clinical manifestations, and response to therapy. In general, women with Parkinson's disease showed more positive disease outcomes with regard to emotion processing, non-motor symptoms, and cognitive functions, although women report more Parkinson's disease-related clinical manifestations. Female gender predicted poor physical functioning and socioemotional health-related quality of life, while male gender predicted the cognitive domain of health-related quality of life. Some studies reported gender differences in the association between health-related quality of life and non-motor symptoms. Depression and fatigue were the main causes of poorer health-related quality of life in women, even in the early stages of Parkinson's disease. The aim of this review was to collect the best available evidence on gender differences in the development of Parkinson's disease symptoms and health-related quality of life.

Inflammation-related gene polymorphisms associated with Parkinson’s disease: an updated meta-analysis

Background

Strong evidence supports the involvement of inflammation processes in the development and progression of Parkinson’s disease (PD), where increasingly correlations have been identified between genetic variations in inflammation-related genes and PD. However, data varies between studies. Therefore, we conducted a meta-analysis to clarify associations between inflammation-related gene polymorphisms and PD risk.

Methods

All studies were identified through online databases. Pooled and stratified groups based on racial descent were assembled to evaluate associations between polymorphisms and PD.

Results

The pooled results showed that protective effects for PD were observed for (1) IL-1α -889 C/T in Asian populations (T vs. C, OR = 0.831, P = 0.031; TT + CT vs. CC, OR = 0.827, P = 0.049); (2) IL-6 -176 G/C in Caucasian populations (CC + GC vs. GG, OR = 0.656, P = 0.000; GC vs. GG, OR = 0.673, P = 0.000); (3) IL-8 -251 A/T (T vs. A, OR = 0.812, P = 0.041; TT vs. AT + AA, OR = 0.663, P = 0.012), particularly in Caucasian populations (TT vs. AT + AA, OR = 0.639, P = 0.010); (4) IL-10 -819 T/C (C vs. T, OR = 0.742, P = 0.034); (5) IL-18 -607 C/A (AA + CA vs. CC, OR = 0.597, P = 0.015; CA vs. CC, OR = 0.534, P = 0.005), and (6) CCR2 +190 G/A (AA vs. GA + GG, OR = 0.552, P = 0.018; AA vs. GG; OR = 0.554; 95% CI 0.336–0.914, P = 0.005). An increased risk of PD was associated with IL-10 -1082 G/A in Asian populations (A vs. G, OR = 1.731, P = 0.000; AA + GA vs. GG, OR = 1.910, P = 0.000). No significant associations with PD were observed for polymorphisms in IL-1β -511 C/T, IL-10 -592 C/A, IL-18 -137 G/C, TNFα -863 C/A, TNFα -857 C/T, TNFα -308 G/A, IFNΥ +874 T/A, and MCP1/CCL2 +2518 A/G.

Conclusions

We suggest that IL-1α -889, IL-6 -176, IL-8 -251, IL-10 -1082, IL-10 -819, IL-18 -607, and CCR2 +190 polymorphisms may be associated with PD risk; however, further studies must verify these conclusions.

Sex differences in movement disorders

In a range of neurological conditions, including movement disorders, sex-related differences are emerging not only in brain anatomy and function, but also in pathogenesis, clinical features and response to treatment. In Parkinson disease (PD), for example, oestrogens can influence the severity of motor symptoms, whereas elevation of androgens can exacerbate tic disorders. Nevertheless, the real impact of sex differences in movement disorders remains under-recognized. In this article, we provide an up-to-date review of sex-related differences in PD and the most common hyperkinetic movement disorders, namely, essential tremor, dystonia, Huntington disease and other chorea syndromes, and Tourette syndrome and other chronic tic disorders. We highlight the most relevant clinical aspects of movement disorders that differ between men and women. Increased recognition of these differences and their impact on patient care could aid the development of tailored approaches to the management of movement disorders and enable the optimization of preclinical research and clinical studies.

Clinical-Pharmacogenetic Predictive Models for Time to Occurrence of Levodopa Related Motor Complications in Parkinson's Disease

The response to dopaminergic treatment in Parkinson's disease depends on many clinical and genetic factors. The very common motor fluctuations (MF) and dyskinesia affect approximately half of patients after 5 years of treatment with levodopa. We did an evaluation of a combined effect of 16 clinical parameters and 34 single nucleotide polymorphisms to build clinical and clinical-pharmacogenetic models for prediction of time to occurrence of motor complications and to compare their predictive abilities. In total, 220 Parkinson's disease patients were included in the analysis. Their demographic, clinical, and genotype data were obtained. The combined effect of clinical and genetic factors was assessed using The Least Absolute Shrinkage and Selection Operator penalized regression in the Cox proportional hazards model. Clinical and clinical-pharmacogenetic models were constructed. The predictive capacity of the models was evaluated with the cross-validated area under time-dependent receiver operating characteristic curve. Clinical-pharmacogenetic model included age at diagnosis (HR = 0.99), time from diagnosis to initiation of levodopa treatment (HR = 1.24), COMT rs165815 (HR = 0.90), DRD3 rs6280 (HR = 1.03), and BIRC5 rs9904341 (HR = 0.95) as predictive factors for time to occurrence of MF. Furthermore, clinical-pharmacogenetic model for prediction of time to occurrence of dyskinesia included female sex (HR = 1.07), age at diagnosis (HR = 0.97), tremor-predominant Parkinson's disease (HR = 0.88), beta-blockers (HR = 0.95), alcohol consumption (HR = 0.99), time from diagnosis to initiation of levodopa treatment (HR = 1.15), CAT rs1001179 (HR = 1.27), SOD2 rs4880 (HR = 0.95), NOS1 rs2293054 (HR = 0.99), COMT rs165815 (HR = 0.92), and SLC22A1 rs628031 (HR = 0.80). Areas under the curves for clinical and clinical-pharmacogenetic models for MF after 5 years of levodopa treatment were 0.68 and 0.70, respectively. Areas under the curves for clinical and clinical-pharmacogenetic models for dyskinesia after 5 years of levodopa treatment were 0.71 and 0.68, respectively. These results show that clinical-pharmacogenetic models do not have better ability to predict time to occurrence of motor complications in comparison to the clinical ones despite the significance of several polymorphisms. Models could be improved by a larger sample size and by additional polymorphisms, epigenetic predictors or serum biomarkers.

Genetic variability of inflammation and oxidative stress genes does not play a major role in the occurrence of adverse events of dopaminergic treatment in Parkinson's disease

BACKGROUND

Inflammation and oxidative stress are recognized as important contributors to Parkinson's disease pathogenesis. As such, genetic variability in these pathways could have a role in susceptibility for the disease as well as in the treatment outcome. Dopaminergic treatment is effective in management of motor symptoms, but poses a risk for motor and non-motor adverse events. Our aim was to evaluate the impact of selected single-nucleotide polymorphisms in genes involved in inflammation and oxidative stress on Parkinson's disease susceptibility and the occurrence of adverse events of dopaminergic treatment.

METHODS

In total, 224 patients were enrolled, and their demographic and clinical data on the disease course were collected. Furthermore, a control group of 146 healthy Slovenian blood donors were included for Parkinson's disease' risk evaluation. Peripheral blood was obtained for DNA isolation. Genotyping was performed for NLRP3 rs35829419, CARD8 rs2043211, IL1β rs16944, IL1β rs1143623, IL6 rs1800795, CAT rs1001179, CAT rs10836235, SOD2 rs4880, NOS1 rs2293054, NOS1 rs2682826, TNF-α rs1800629, and GPX1 rs1050450. Logistic regression was used for analysis of possible associations.

RESULTS

We observed a nominally significant association of the IL1β rs1143623 C allele with the risk for Parkinson's disease (OR = 0.59; 95%CI = 0.38-0.92, p = 0.021). CAT rs1001179 A allele was significantly associated with peripheral edema (OR = 0.32; 95%CI = 0.15-0.68; p = 0.003). Other associations observed were only nominally significant after adjustments: NOS1 rs2682826 A allele and excessive daytime sleepiness and sleep attacks (OR = 1.75; 95%CI = 1.00-3.06, p = 0.048), SOD2 rs4880 T allele and nausea/vomiting (OR = 0.49, 95%CI = 0.25-0.94; p = 0.031), IL1β rs1143623 C allele and orthostatic hypotension (OR = 0.57, 95%CI = 0.32-1.00, p = 0.050), and NOS1 rs2682826 A allele and impulse control disorders (OR = 2.59; 95%CI = 1.09-6.19; p = 0.032). We did not find any associations between selected polymorphisms and motor adverse events.

CONCLUSIONS

Apart from some nominally significant associations, one significant association between CAT genetic variability and peripheral edema was observed as well. Therefore, the results of our study suggest some links between genetic variability in inflammation- and oxidative stress-related pathways and non-motor adverse events of dopaminergic treatment. However, the investigated polymorphisms do not play a major role in the occurrence of the disease and the adverse events of dopaminergic treatment.

Sex differences in Parkinson's disease: Features on clinical symptoms, treatment outcome, sexual hormones and genetics

Parkinson's disease (PD) is the second most frequent age-related neurodegenerative disorder. Sex is an important factor in the development of PD, as reflected by the fact that it is more common in men than in women by an approximate ratio of 2:1. Our hypothesis is that differences in PD among men and women are highly determined by sex-dependent differences in the nigrostriatal dopaminergic system, which arise from environmental, hormonal and genetic influences. Sex hormones, specifically estrogens, influence PD pathogenesis and might play an important role in PD differences between men and women. The objective of this review was to discuss the PD physiopathology and point out sex differences in nigrostriatal degeneration, symptoms, genetics, responsiveness to treatments and biochemical and molecular mechanisms among patients suffering from this disease. Finally, we discuss the role estrogens may have on PD sex differences.

Sex differences in LRRK2 G2019S and idiopathic Parkinson's Disease

Objective

To evaluate sex differences and the relative effect of G2019S LRRK2 mutations in Parkinson's disease (PD).

Methods

530 LRRK2 PD carriers and 759 noncarrier PD (idiopathic, IPD) evaluated as part of the Fox Foundation (MJFF) Consortium were included. All participants completed a study visit including information on clinical features, treatment, examination, and motor and nonmotor questionnaires. Clinical features were compared between men and women separately for IPD and LRRK2 PD; and features were compared between IPD and LRRK2 PD separately for men and women.

Results

Among IPD: men had higher levodopa equivalency dose (LED), worse activities of daily living and motoric severity but lower complications of therapy (UPDRS-IV). IPD women had higher olfaction and thermoregulatory scores and were more likely to report family history of PD. Among LRRK2 PD: Male predominance was not observed among G2019S LRRK2 cases. Women had worse UPDRS-IV but better olfaction. Among same sex:LRRK2 men and women had better olfaction than IPD counterparts. LRRK2 men demonstrated lower motor and higher cognitive, RBD and thermoregulation scores than IPD men and LRRK2 women had greater UDPRS-IV and rates of dyskinesia.

Interpretation

There were clinical differences between sexes with a more severe phenotype in IPD men and more complications of therapy in women. The more severe male phenotype was moderated by LRRK2, with LRRK2 men and women showing less diversity of phenotype. Our study supports that both genetics and sex drive phenotype, and thus trials in LRRK2 and IPD should consider gender stratification in design or analysis.

Genetic polymorphisms in VDR, ESR1 and ESR2 genes may contribute to susceptibility to Parkinson's disease: a meta-analysis

We conducted this meta-analysis of relevant case-control studies to investigate the relationships between genetic polymorphisms in VDR, ESR1 and ESR2 genes to the susceptibility of Parkinson's disease (PD). A search on electronic databases without any language restrictions was conducted: MEDLINE (1966-2013), the Cochrane Library Database (Issue 12, 2013), EMBASE (1980-2013), CINAHL (1982-2013), Web of Science (1945-2013) and the Chinese Biomedical Database (1982-2013). Meta-analysis was performed using the STATA statistical software. Crude odds ratio (OR) with their 95% confidence interval (95% CI) was calculated. Fourteen case-control studies with a total of 3,689 PD patients and 4,627 healthy subjects were included in our meta-analysis. The results of our meta-analysis demonstrated that the VDR genetic polymorphisms might be closely related to increased risks of PD (allele model: OR = 1.18, 95% CI 1.09-1.29, P < 0.001; dominant model: OR = 1.37, 95% CI 1.16-1.63, P < 0.001; respectively), especially for the polymorphisms rs7976091 and rs10735810. Our findings also illustrated that ESR1 genetic polymorphisms might increase the risk of PD (allele model: OR = 1.56, 95% CI 1.17-2.07, P = 0.002; recessive model: OR = 1.93, 95 % CI 1.33-2.80, P < 0.001; homozygous model: OR = 1.35, 95% CI 1.02-1.79, P = 0.038; heterozygous model: OR = 2.04, 95% CI 1.36-3.07, P = 0.001; respectively), especially for the polymorphisms rs2234693 and rs9340799. Furthermore, we found significant correlations of ESR2 genetic polymorphisms with the risk of PD (allele model: OR = 1.78, 95% CI 1.19-2.67, P = 0.005; recessive model: OR = 1.93, 95% CI 1.15-3.27, P = 0.014; homozygous model: OR = 1.77, 95% CI 1.09-2.89, P = 0.022; heterozygous model: OR = 1.88, 95% CI 1.08-3.27, P = 0.025; respectively), especially for the rs1256049 polymorphism. Our meta-analysis suggests that genetic polymorphisms in VDR, ESR1 and ESR2 genes may contribute to increased risks for PD.

Genetics of leprosy reactions: an overview

Type-1 (T1R) and Type-2 (T2R) leprosy reactions (LR), which affect up to 50% of leprosy patients, are aggressive inflammatory episodes of sudden onset and highly variable incidence across populations. LR are often diagnosed concurrently with leprosy, but more frequently occur several months after treatment onset. It is not uncommon for leprosy patients to develop recurring reactional episodes; however, they rarely undergo both types of LR. Today, LR are the main cause of permanent disabilities associated with leprosy and represent a major challenge in the clinical management of leprosy patients. Although progress has been made in understanding the immunopathology of LR, the factors that cause a leprosy patient to suffer from LR are largely unknown. Given the impact that ethnic background has on the risk of developing LR, host genetic factors have long been suspected of contributing to LR. Indeed, polymorphisms in seven genes [Toll-like receptors (TLR)1, TLR2, nucleotide-binding oligomerisation domain containing 2, vitamin D receptor, natural resistance-associated macrophage protein 1, C4B and interleukin-6] have been found to be associated with one or more LR outcomes. The identification of host genetic markers with predictive value for LR would have a major impact on nerve damage control in leprosy. In this review, we present the recent advances achieved through genetic studies of LR.