Gender-specific brain regional variation of neurons, endogenous estrogen, neuroinflammation and glial cells during rotenone-induced mouse model of Parkinson's disease

Potential Regulation of the Long Non-Coding RNA Metastasis-Associated Lung Adenocarcinoma Transcript1 by Estrogen in Parkinson's Disease

Parkinson's disease (PD) is the second-leading cause of death among neurodegenerative disease after Alzheimer's disease (AD), affecting around 2% of the population. It is expected that the incidence of PD will exceed 12 million by 2040. Meanwhile, there is a recognized difference in the phenotypical expression of the disease and response to treatment between men and women. Men have twice the incidence of PD compared to women, who have a late onset and worse prognosis that is usually associated with menopause. In addition, the incidence of PD in women is associated with the cumulative estrogen levels in their bodies. These differences are suggested to be due to the protective effect of estrogen on the brain, which cannot be given in clinical practice to improve the symptoms of the disease because of its peripheral side effects, causing cancer in both males and females in addition to the feminizing effect it has on males. As PD pathophysiology involves alteration in the expression levels of multiple LncRNAs, including metastatic-associated lung adenocarcinoma transcript 1 (MALAT1), and as estrogen has been illustrated to control the expression of MALAT1 in multiple conditions, it is worth investigating the estrogen-MALAT1 interaction in Parkinson's disease to mimic its protective effect on the brain while avoiding its peripheral side effects. The following literature review suggests the potential regulation of MALAT1 by estrogen in PD, which would enhance our understanding of the pathophysiology of the disease, improving the development of more tailored and effective treatments.

Inflammation and heterogeneity in synucleinopathies

Neurodegenerative diseases represent a huge healthcare challenge which is predicted to increase with an aging population. Synucleinopathies, including Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), present complex challenges in understanding their onset and progression. They are characterized by the abnormal aggregation of α-synuclein in the brain leading to neurodegeneration. Accumulating evidence supports the existence of distinct subtypes based on the site of α-synuclein aggregation initiation, genetics, and, more recently, neuroinflammation. Mediated by both central nervous system-resident cells, peripheral immune cells, and gut dysbiosis, neuroinflammation appears as a key process in the onset and progression of neuronal loss. Sex-based differences add another layer of complexity to synucleinopathies, influencing disease prevalence - with a known higher incidence of PD in males compared to females - as well as phenotype and immune responses. Biological sex affects neuroinflammatory pathways and the immune response, suggesting the need for sex-specific therapeutic strategies and biomarker identification. Here, we review the heterogeneity of synucleinopathies, describing the etiology, the mechanisms by which the inflammatory processes contribute to the pathology, and the consideration of sex-based differences to highlight the need for personalized therapeutics.

The identification of cianidanol as a selective estrogen receptor beta agonist and evaluation of its neuroprotective effects on Parkinson's disease models

AIM

The present study aims to identify selective estrogen receptor beta (ERβ) agonists and to evaluate the neuroprotective mechanism in Parkinson's disease (PD) models.

MAIN METHODS

In-silico studies were carried out using Maestro and GROMACS. Neuroprotective activity and apoptosis were evaluated using cytotoxicity assay and flow cytometry respectively. Gene expression studies were carried out by reverse transcription polymerase chain reaction. Motor and cognitive functions were assessed by actophotometer, rotarod, catalepsy, and elevated plus maze. The neuronal population in the substantia nigra and striatum of rats was assessed by hematoxylin and eosin staining.

KEY FINDINGS

Cianidanol was identified as a selective ERβ agonist through virtual screening. The cianidanol-ERβ complex is stable during the 200 ns simulation and was able to retain the interactions with key amino acid residues. Cianidanol (25 μM) prevents neuronal toxicity and apoptosis induced by rotenone in differentiated SH-SY5Y cells. Additionally, cianidanol (25 μM) increases the expression of ERβ, cathepsin D, and Nrf2 transcripts. The neuroprotective effects of cianidanol (25 μM) were reversed in the presence of a selective ERβ antagonist. In this study, we found that selective activation of ERβ could decrease the transcription of α-synuclein gene. Additionally, cianidanol (10, 20, 30 mg/kg, oral) improves the motor and cognitive deficit in rats induced by rotenone.

SIGNIFICANCE

Cianidanol shows neuroprotective action in PD models and has the potential to serve as a novel therapeutic agent for the treatment of PD.

Voltage-Gated Proton Channel Hv1 Regulates Neuroinflammation and Dopaminergic Neurodegeneration in Parkinson's Disease Models

Although the precise mechanisms for neurodegeneration in Parkinson's disease (PD) are unknown, evidence suggests that neuroinflammation is a critical factor in the pathogenic process. Here, we sought to determine whether the voltage-gated proton channel, Hv1 (HVCN1), which is expressed in microglia and regulates NADPH oxidase, is associated with dopaminergic neurodegeneration. We utilized data mining to evaluate the mRNA expression of HVCN1 in the brains of PD patients and controls and uncovered increased expression of the gene encoding Hv1, HVCN1, in the brains of PD patients compared to controls, specifically in male PD patients. In an acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 4 × 16 mg/kg) mouse model of PD, Hvcn1 gene expression was increased 2-fold in the striatum. MPTP administration to wild-type (WT) mice resulted in a ~65% loss of tyrosine hydroxylase positive neurons (TH+) in the substantia nigra (SN), while a ~39% loss was observed in Hv1 knockout (KO) mice. Comparable neuroprotective effects of Hv1 deficiency were found in a repeated-dose LPS model. Neuroprotection was associated with decreased pro-inflammatory cytokine levels and pro-oxidant factors in both neurotoxicant animal models. These in vivo results were confirmed in primary microglial cultures, with LPS treatment increasing Hvcn1 mRNA levels and Hv1 KO microglia failing to exhibit the LPS-mediated inflammatory response. Conditioned media from Hv1 KO microglia treated with LPS resulted in an attenuated loss of cultured dopamine neuron cell viability compared to WT microglia. Taken together, these data suggest that Hv1 is upregulated and mediates microglial pro-inflammatory cytokine production in parkinsonian models and therefore represents a novel target for neuroprotection.

Neuroimmune transcriptome changes in patient brains of psychiatric and neurological disorders

Neuroinflammation has been implicated in multiple brain disorders but the extent and the magnitude of change in immune-related genes (IRGs) across distinct brain disorders has not been directly compared. In this study, 1275 IRGs were curated and their expression changes investigated in 2467 postmortem brains of controls and patients with six major brain disorders, including schizophrenia (SCZ), bipolar disorder (BD), autism spectrum disorder (ASD), major depressive disorder (MDD), Alzheimer's disease (AD), and Parkinson's disease (PD). There were 865 IRGs present across all microarray and RNA-seq datasets. More than 60% of the IRGs had significantly altered expression in at least one of the six disorders. The differentially expressed immune-related genes (dIRGs) shared across disorders were mainly related to innate immunity. Moreover, sex, tissue, and putative cell type were systematically evaluated for immune alterations in different neuropsychiatric disorders. Co-expression networks revealed that transcripts of the neuroimmune systems interacted with neuronal-systems, both of which contribute to the pathology of brain disorders. However, only a few genes with expression changes were also identified as containing risk variants in genome-wide association studies. The transcriptome alterations at gene and network levels may clarify the immune-related pathophysiology and help to better define neuropsychiatric and neurological disorders.

Sexual Dimorphism in Neurodegenerative Diseases and in Brain Ischemia

Epidemiological studies and clinical observations show evidence of sexual dimorphism in brain responses to several neurological conditions. It is suggested that sex-related differences between men and women may have profound effects on disease susceptibility, pathophysiology, and progression. Sexual differences of the brain are achieved through the complex interplay of several factors contributing to this phenomenon, such as sex hormones, as well as genetic and epigenetic differences. Despite recent advances, the precise link between these factors and brain disorders is incompletely understood. This review aims to briefly outline the most relevant aspects that differ between men and women in ischemia and neurodegenerative disorders (AD, PD, HD, ALS, and SM). Recognition of disparities between both sexes could aid the development of individual approaches to ameliorate or slow the progression of intractable disorders.

Unveiling sex-based differences in Parkinson's disease: a comprehensive meta-analysis of transcriptomic studies

BACKGROUND

In recent decades, increasing longevity (among other factors) has fostered a rise in Parkinson's disease incidence. Although not exhaustively studied in this devastating disease, the impact of sex represents a critical variable in Parkinson's disease as epidemiological and clinical features differ between males and females.

METHODS

To study sex bias in Parkinson's disease, we conducted a systematic review to select sex-labeled transcriptomic data from three relevant brain tissues: the frontal cortex, the striatum, and the substantia nigra. We performed differential expression analysis on each study chosen. Then we summarized the individual differential expression results with three tissue-specific meta-analyses and a global all-tissues meta-analysis. Finally, results from the meta-analysis were functionally characterized using different functional profiling approaches.

RESULTS

The tissue-specific meta-analyses linked Parkinson's disease to the enhanced expression of MED31 in the female frontal cortex and the dysregulation of 237 genes in the substantia nigra. The global meta-analysis detected 15 genes with sex-differential patterns in Parkinson's disease, which participate in mitochondrial function, oxidative stress, neuronal degeneration, and cell death. Furthermore, functional analyses identified pathways, protein-protein interaction networks, and transcription factors that differed by sex. While male patients exhibited changes in oxidative stress based on metal ions, inflammation, and angiogenesis, female patients exhibited dysfunctions in mitochondrial and lysosomal activity, antigen processing and presentation functions, and glutamic and purine metabolism. All results generated during this study are readily available by accessing an open web resource ( http://bioinfo.cipf.es/metafun-pd/ ) for consultation and reuse in further studies.

CONCLUSIONS

Our in silico approach has highlighted sex-based differential mechanisms in typical Parkinson Disease hallmarks (inflammation, mitochondrial dysfunction, and oxidative stress). Additionally, we have identified specific genes and transcription factors for male and female Parkinson Disease patients that represent potential candidates as biomarkers to diagnosis.

State-of-the-art review of the clinical research on menopause and hormone replacement therapy association with Parkinson's disease: What meta-analysis studies cannot tell us

The menopause is a midlife endocrinological process that greatly affects women's central nervous system functions. Over the last 2 decades numerous clinical studies have addressed the influence of ovarian hormone decline on neurological disorders like Parkinson's disease and Alzheimer's disease. However, the findings in support of a role for age at menopause, type of menopause and hormone replacement therapy on Parkinson's disease onset and its core features show inconsistencies due to the heterogeneity in the study design. Here, we provide a unified overview of the clinical literature on the influence of menopause and ovarian hormones on Parkinson's disease. We highlight the possible sources of conflicting evidence and gather considerations for future observational clinical studies that aim to explore the neurological impact of menopause-related features in Parkinson's disease.

Taste Impairments in a Parkinson’s Disease Model Featuring Intranasal Rotenone Administration in Mice

Background: Taste impairments are often accompanied by olfactory impairments in the early stage of Parkinson’s disease (PD). The development of animal models is required to elucidate the mechanisms underlying taste impairments in PD. Objective: This study was conducted to clarify whether the intranasal administration of rotenone causes taste impairments prior to motor deficits in mice. Methods: Rotenone was administrated to the right nose of mice once a day for 1 or 4 week(s). In the 1-week group, taste, olfactory, and motor function was assessed before and after a 1-week recovery period following the rotenone administration. Motor function was also continuously examined in the 4-weeks group from 0 to 5 weeks. After a behavioral test, the number of catecholamine neurons (CA-Nos) was counted in the regions responsible for taste, olfactory, and motor function. Results: taste and olfactory impairments were simultaneously observed without locomotor impairments in the 1-week group. The CA-Nos was significantly reduced in the olfactory bulb and nucleus of the solitary tract. In the 4-week group, locomotor impairments were observed from the third week, and a significant reduction in the CA-Nos was observed in the substantia nigra (SN) and ventral tegmental area (VTA) at the fifth week along with the weight loss. Conclusion: The intranasal administration of rotenone caused chemosensory and motor impairments in an administration time-period dependent manner. Since chemosensory impairments were expressed prior to the locomotor impairments followed by SN/VTA CA neurons loss, this rotenone administration model may contribute to the clarification of the prodromal symptoms of PD.

Vortioxetine ameliorates motor and cognitive impairments in the rotenone-induced Parkinson's disease via targeting TLR-2 mediated neuroinflammation

Parkinson's disease (PD) is characterized by motor and non-motor symptoms associated with dopaminergic and non-dopaminergic injury. Vortioxetine is a multimodal serotonergic antidepressant with potential procognitive effects. This study aimed to explore the effects of vortioxetine on motor functions, spatial learning and memory, and depression-like behavior in the rotenone-induced rat model of PD. Male Sprague-Dawley rats were daily administered with the rotenone (2 mg·kg^-1, s.c.) and/or vortioxetine (10 mg·kg^-1, s.c.) for 28 days. Motor functions (rotarod, catalepsy, open-field), depression-like behaviors (sucrose preference test), anxiety (elevated plus maze), and spatial learning and memory abilities (novel object recognition and Morris water maze) were evaluated in behavioral tests. Then immunohistochemical, neurochemical, and biochemical analysis on specific brain areas were performed. Vortioxetine treatment markedly reduced rotenone-induced neurodegeneration, improved motor and cognitive dysfunction, decreased depression-like behaviors without affecting anxiety-like parameters. Vortioxetine also restored the impaired inflammatory response and affected neurotransmitter levels in brain tissues. Interestingly, vortioxetine was thought to trigger a sort of dysfunction in basal ganglia as evidenced by increased Toll-like receptor-2 (TLR-2) and decreased TH immunoreactivity only in substantia nigra tissue of PD rats compared to the control group. The present study indicates that vortioxetine has beneficial effects on motor dysfunction as well as cognitive impairment associated with neurodegeneration in the rotenone-induced PD model. Possible mechanisms underlying these beneficial effects cover TLR-2 inhibition and neurochemical restoration of vortioxetine.

Effect of sex and gonadectomy on brain MPTP toxicity and response to dutasteride treatment in mice

The main neuropathological feature of Parkinson's disease (PD) is degeneration of dopamine (DA) neurons in the substantia nigra (SN); PD prevalence is higher in men, suggesting a role of sex hormones in neuroprotection. This study sought the effects of sex hormones in the brain in a mouse model of PD and modulation of steroid metabolism/synthesis with the 5α-reductase inhibitor dutasteride shown to protect 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) male mice. Male and female mice were gonadectomized (GDX) or SHAM operated. They were treated with vehicle or dutasteride (5 mg/kg) for 10 days and administered a low dose of MPTP (5.5 mg/kg) or saline on the 5th day to model early PD; brains were collected thereafter. Striatal measures of the active metabolite 1-methyl-4-phenylpyridinium (MPP+) contents showed no difference supporting an effect of the experimental conditions investigated. In SHAM MPTP male mice loss of striatal DA and metabolites, DA transporter (DAT) and vesicular monoamine transporter 2 (VMAT2) specific binding in the striatum and SN was prevented by dutasteride treatment; these changes were inversely correlated with glial fibrillary acidic protein (GFAP, an astrogliosis marker) levels. In SHAM female mice MPTP treatment had little or no effect on striatal and SN DA markers and GFAP levels whereas GDX male and female mice showed a similar loss of striatal DA markers and increase of GFAP. No effect of dutasteride treatment was observed in GDX male and female mice. In conclusion, sex differences in mice MPTP toxicity and response to dutasteride were observed that were lost upon gonadectomy implicating neuroinflammation.

Using Rotenone to Model Parkinson's Disease in Mice: A Review of the Role of Pharmacokinetics

Rotenone is a naturally occurring toxin that inhibits complex I of the mitochondrial electron transport chain. Several epidemiological studies have shown an increased risk of Parkinson's disease (PD) in individuals exposed chronically to rotenone, and it has received great attention for its ability to reproduce many critical features of PD in animal models. Laboratory studies of rotenone have repeatedly shown that it induces in vivo substantia nigra dopaminergic cell loss, a hallmark of PD neuropathology. Additionally, rotenone induces in vivo aggregation of α-synuclein, the major component of Lewy bodies and Lewy neurites found in the brain of PD patients and another hallmark of PD neuropathology. Some in vivo rotenone models also reproduce peripheral signs of PD, such as reduced intestinal motility and peripheral α-synuclein aggregation, both of which are thought to precede classical signs of PD in humans, such as cogwheel rigidity, bradykinesia, and resting tremor. Nevertheless, variability has been noted in cohorts of animals exposed to the same rotenone exposure regimen and also between cohorts exposed to similar doses of rotenone. Low doses, administered chronically, may reproduce PD symptoms and neuropathology more faithfully than excessively high doses, but overlap between toxicity and parkinsonian motor phenotypes makes it difficult to separate if behavior is examined in isolation. Rotenone degrades when exposed to light or water, and choice of vehicle may affect outcome. Rotenone is metabolized extensively in vivo, and choice of route of exposure influences greatly the dose used. However, male rodents may be capable of greater metabolism of rotenone, which could therefore reduce their total body exposure when compared with female rodents. The pharmacokinetics of rotenone has been studied extensively, over many decades. Here, we review these pharmacokinetics and models of PD using this important piscicide.

Microglial Activation Mediates Noradrenergic Locus Coeruleus Neurodegeneration via Complement Receptor 3 in a Rotenone-Induced Parkinson's Disease Mouse Model

Background

Chronic exposure to the insecticide rotenone can damage dopaminergic neurons and lead to an increased risk of Parkinson’s disease (PD). Whereas it is not clear whether rotenone induces neurodegeneration of noradrenergic locus coeruleus (LC/NE) neurons. Chronic neuroinflammation mediated by microglia has been involved in the pathogenesis of PD. Evidence shows that complement receptor 3 (CR3) is a crucial regulator of microglial activation and related neurodegeneration. However, it is not clear whether CR3 mediates rotenone-elicited degeneration of LC/NE neurons through microglia-mediated neuroinflammation.

Materials and Methods

Wild type (WT) and CR3 knockout (KO) mice were treated with rotenone. PLX3397 and minocycline were used to deplete or inactivate the microglia. Leukadherin-1 (LA-1) was used to modulate CR3. LC/NE neurodegeneration, microglial phenotype, and expression of CR3 were determined by using immunohistochemistry, Western blot and real-time polymerase chain reaction (PCR) techniques. The glutathione (GSH) and malondialdehyde (MDA) contents were measured by using commercial kits.

Results

Rotenone exposure led to dose- and time-dependent LC/NE neuronal loss and microglial activation in mice. Depletion of microglia by PLX3397 or inhibition of microglial activation by minocycline significantly reduced rotenone-induced LC/NE neurodegeneration. Mechanistic studies revealed that CR3 played an essential role in the rotenone-induced activation of microglia and neurodegeneration of LC/NE neurons. Rotenone elevated the expression of CR3, and genetic ablation of CR3 markedly reduced rotenone-induced microglial activation and M1 polarization. LA-1 also suppressed rotenone-induced toxic microglial M1 activation. Furthermore, lack of CR3 or treatment with LA-1 reduced oxidative stress in the brainstem of rotenone-intoxicated mice. Finally, we found that mice deficient in CR3 or treated with LA-1 were more resistant to rotenone-induced LC/NE neurodegeneration than WT or vehicle-treated mice, respectively.

Conclusion

Our results indicate that CR3-mediated microglial activation participates in rotenone-induced LC/NE neurodegeneration, providing novel insight into environmental toxin-induced neurotoxicity and related Parkinsonism.

Sex effects on clinical features in LRRK2 G2385R carriers and non-carriers in Parkinson's disease

BACKGROUND

Differences of genotypes between male and female have been studied in Parkinson's disease (PD), but limited research has focused on the comparison between sexes with LRRK2 G2385 variant.

OBJECTIVE

The aim of this study was to explore sex effects in the same genetic subtype and role of leucine-rich repeat kinase 2 (LRRK2) G2385R variants in the same sex in PD.

METHODS

613 PD patients were recruited from the Movement Disorders Clinic in Ruijin Hospital. We did not include healthy controls in this study. The data collected includes demographic information, disease history, scores of motor and non-motor symptoms scales, midbrain transcranial sonography and DNA. Binary logistic regression analysis was performed to evaluate the association between clinical features and sex in LRRK2 G2385R carriers and non-carriers, as well as the association between the clinical features and LRRK2 G2385R variants in male and female sex.

RESULTS

Sex distribution is similar in LRRK2 G2385R carriers and non-carriers. In male sex, LRRK2 G2385R carriers showed lower risk in cognitive impairment compared with non-carriers (OR = 0.301, p = 0.003, 95%CI 0.135-0.668). In female sex, LRRK2 G2385R carriers showed lower risk in autonomic dysfunction compared with non-carrier (OR = 0.401, p = 0.040, 95%CI 0.167-0.960). In LRRK2 G2385R non-carriers, female sex showed lower risk of impairment in activity of daily living (OR = 0.610, p = 0.021, 95%CI 0.400-0.928), excessive daytime sleepiness (OR = 0.555, p = 0.007, 95%CI 0.361-0.853), substantia nigra hyperechogenicity (OR = 0.448, p = 0.019, 95%CI 0.228-0.878), autonomic dysfunction frequency (OR = 0.626, p = 0.016, 95%CI 0.428-0.917) and higher risk in mood disorders (OR = 1.691, p = 0.022, 95%CI 1.078-2.654) compared with male. In LRRK2 G2385R carriers, female sex showed a lower risk of autonomic dysfunction (OR = 0.294, p = 0.024, 95%CI 0.102-0.849) compared with male.

CONCLUSION

In contrast to male PD patients, a more benign disease course was observed in female in both LRRK2 G2385R carriers and non-carriers. However, sex differences were less notable in PD with LRRK2 G2385R variants.

Role of glial cells in the generation of sex differences in neurodegenerative diseases and brain aging

Diseases and aging-associated alterations of the nervous system often show sex-specific characteristics. Glial cells play a major role in the endogenous homeostatic response of neural tissue, and sex differences in the glial transcriptome and function have been described. Therefore, the possible role of these cells in the generation of sex differences in pathological alterations of the nervous system is reviewed here. Studies have shown that glia react to pathological insults with sex-specific neuroprotective and regenerative effects. At least three factors determine this sex-specific response of glia: sex chromosome genes, gonadal hormones and neuroactive steroid hormone metabolites. The sex chromosome complement determines differences in the transcriptional responses in glia after brain injury, while gonadal hormones and their metabolites activate sex-specific neuroprotective mechanisms in these cells. Since the sex-specific neuroprotective and regenerative activity of glial cells causes sex differences in the pathological alterations of the nervous system, glia may represent a relevant target for sex-specific therapeutic interventions.

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.

Transcriptome alterations in female Daphnia (Daphnia magna) exposed to 17β-estradiol

The molecular mechanism of evaluating 17β-estradiol (E₂)-induced toxicity in female Daphnia magna has not been determined. In this study, the transcriptome of D. magna was analyzed after exposure to three different concentrations (0, 10, and 100 ng L^-1) of E₂ at 3, 6, and 12 h. The results showed 351-17,221 significantly up-regulated and 505-10,282 significantly down-regulated genes (P < 0.05). Overall, the selected largest 10,282 (10 ng L^-1vs control at 12 h) down-regulated and 17,221 (100 vs 10 ng L^-1) up-regulated genes were identified; following annotation, pathways in cancer and RNA transport were found to be enriched according to the interaction network. Among all completed comparisons, KEGG pathways related to the immune system, cancer, disease infection, and active compound metabolism were identified by short time series expression miner analysis. A different set of genes fluctuated in a "U"-shaped pattern over time and at different concentrations of E₂, whereas some genes associated with disintoxication showed a reverse "U"-shaped response as E₂ administration was increased. These results suggest that E₂ exposure caused transcriptional changes in the immune system, disintoxication, disease prevention, and the protein degradation pathway.

Cold-inducible protein RBM3 mediates hypothermic neuroprotection against neurotoxin rotenone via inhibition on MAPK signalling

Mild hypothermia and its key product, cold-inducible protein RBM3, possess robust neuroprotective effects against various neurotoxins. However, we previously showed that mild hypothermia fails to attenuate the neurotoxicity from MPP+ , one of typical neurotoxins related to the increasing risk of Parkinson disease (PD). To better understand the role of mild hypothermia and RBM3 in PD progression, another known PD-related neurotoxin, rotenone (ROT) was utilized in this study. Using immunoblotting, cell viability assays and TUNEL staining, we revealed that mild hypothermia (32°C) significantly reduced the apoptosis induced by ROT in human neuroblastoma SH-SY5Y cells, when compared to normothermia (37°C). Meanwhile, the overexpression of RBM3 in SH-SY5Y cells mimicked the neuroprotective effects of mild hypothermia on ROT-induced cytotoxicity. Upon ROT stimulation, MAPK signalling like p38, JNK and ERK, and AMPK and GSK-3β signalling were activated. When RBM3 was overexpressed, only the activation of p38, JNK and ERK signalling was inhibited, leaving AMPK and GSK-3β signalling unaffected. Similarly, mild hypothermia also inhibited the activation of MAPKs induced by ROT. Lastly, it was demonstrated that the MAPK (especially p38 and ERK) inhibition by their individual inhibitors significantly decreased the neurotoxicity of ROT in SH-SY5Y cells. In conclusion, these data demonstrate that RBM3 mediates mild hypothermia-related neuroprotection against ROT by inhibiting the MAPK signalling of p38, JNK and ERK.

Sex-specific neuroprotection by inhibition of the Y-chromosome gene, SRY, in experimental Parkinson's disease

Parkinson's disease (PD) is a debilitating neurodegenerative disorder caused by the loss of midbrain dopamine (DA) neurons. While the cause of DA cell loss in PD is unknown, male sex is a strong risk factor. Aside from the protective actions of sex hormones in females, emerging evidence suggests that sex-chromosome genes contribute to the male bias in PD. We previously showed that the Y-chromosome gene, SRY, directly regulates adult brain function in males independent of gonadal hormone influence. SRY protein colocalizes with DA neurons in the male substantia nigra, where it regulates DA biosynthesis and voluntary movement. Here we demonstrate that nigral SRY expression is highly and persistently up-regulated in animal and human cell culture models of PD. Remarkably, lowering nigral SRY expression with antisense oligonucleotides in male rats diminished motor deficits and nigral DA cell loss in 6-hydroxydopamine (6-OHDA)-induced and rotenone-induced rat models of PD. The protective effect of the SRY antisense oligonucleotides was associated with male-specific attenuation of DNA damage, mitochondrial degradation, and neuroinflammation in the toxin-induced rat models of PD. Moreover, reducing nigral SRY expression diminished or removed the male bias in nigrostriatal degeneration, mitochondrial degradation, DNA damage, and neuroinflammation in the 6-OHDA rat model of PD, suggesting that SRY directly contributes to the sex differences in PD. These findings demonstrate that SRY directs a previously unrecognized male-specific mechanism of DA cell death and suggests that suppressing nigral Sry synthesis represents a sex-specific strategy to slow or prevent DA cell loss in PD.

Hazardous effects of chemical pesticides on human health-Cancer and other associated disorders

Poisoning from pesticides is a global public health problem and accounts for nearly 300,000 deaths worldwide every year. Exposure to pesticides is inevitable; there are different modes through which humans get exposed to pesticides. The mode of exposure is an important factor as it also signifies the concentration of pesticides exposure. Pesticides are used extensively in agricultural and domestic settings. These chemicals are believed to cause many disorders in humans and wildlife. Research from past few decades has tried to answer the associated mechanism of action of pesticides in conjunction with their harmful effects. This perspective considers the past and present research in the field of pesticides and associated disorders. We have reviewed the most common diseases including cancer which are associated with pesticides. Pesticides have shown to be involved in the pathogenesis of Parkinson's and Alzheimer's diseases as well as various disorders of the respiratory and reproductive tracts. Oxidative stress caused by pesticides is an important mechanism through which many of the pesticides exert their harmful effects. Oxidative stress is known to cause DNA damage which in turn may cause malignancies and other disorders. Many pesticides have shown to modulate the gene expression at the level of non-coding RNAs, histone deacetylases, DNA methylation patterns suggesting their role in epigenetics.

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.

TNFR2 mediated TNF-α signaling and NF-κB activation in hippocampus of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mice

1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine (MPTP) -induced neuroinflammation and its impact in hippocampus remain elusive till date. Our present study includes the time dependent changes of inflammatory molecules in mouse hippocampus during MPTP treatment. MPTP treatment increased level of TNF-α, enhanced expression of TNFR2 along with PI3 kinase (PI3K) induced phosphorylation of Akt resulting in persistent nuclear factor-κB (NF-κB) activation. The expressions gradually increased from Day1 post-MPTP treatment, maximally at Day3 post-treatment. MPTP induced translocation of p65 and p52, two subunits of NF-κB family, to nucleus where they had been found to dimerize. Therefore, MPTP induced TNF-α signaling through TNFR2 mediated pathway and recruited p65-p52 dimer in hippocampal nucleus which is reported to have protective effect on hippocampal neurons indicated by unchanged neuronal count in hippocampus in treated groups with respect to control. Our finding suggests that this unique NF-κB dimer plays some role in providing inherent protection to hippocampus during MPTP-treatment.

Occupational and environmental exposure to pesticides and cytokine pathways in chronic diseases (Review)

Pesticides can exert numerous effects on human health as a consequence of both environmental and occupational exposures. The available knowledge base suggests that exposure to pesticides may result in detrimental reproductive changes, neurological dysfunction and several chronic disorders, which are defined by slow evolution and long-term duration. Moreover, an ever increasing amount of data have identified an association between exposure to pesticides and the harmful effects on the immune system. The real impact of alterations in humoral cytokine levels on human health, in particular in the case of chronic diseases, is still unclear. To date, studies have suggested that although exposure to pesticides can affect the immune system functionally, the development of immune disorders depends on the dose and duration of exposure to pesticides. However, many of the respective studies exhibit limitations, such as a lack of information on exposure levels, differences in the pesticide administration procedures, difficulty in characterizing a prognostic significance to the weak modifications often observed and the interpretation of obtained results. The main challenge is not just to understand the role of individual pesticides and their combinations, but also to determine the manner and the duration of exposure, as the toxic effects on the immune system cannot be separated from these considerations. There is a clear need for more well-designed and standardized epidemiological and experimental studies to recognize the exact association between exposure levels and toxic effects and to identify useful biomarkers of exposure. This review focuses on and critically discusses the immunotoxicity of pesticides and the impact of cytokine levels on health, focusing on the development of several chronic diseases.

Impact of Sex on the Nonmotor Symptoms and the Health-Related Quality of Life in Parkinson's Disease

Background. Female Parkinson's disease (PD) patients seem to experience not only more severe motor complications and postural instability but also more pronounced depression, anxiety, pain, and sleep disturbances. Objective. The aim of the present study was to evaluate the role of sex as a possible independent predictor of HRQoL in PD. Methods. In this cross-sectional study, 621 consecutive patients treated at the University of Pécs were enrolled. Severity of PD symptoms was assessed by MDS-UPDRS, UDysRS, Non-Motor Symptoms Scale, PDSS-2, Hamilton Anxiety Scale, Montgomery-Asberg Depression Rating Scale, Lille Apathy Rating Scale, and Addenbrooke Cognitive Examination. HRQoL was assessed by PDQ-39 and EQ-5D. Multiple regression analysis was performed to estimate the PDQ-39 and EQ-5D index values based on various clinical factors. Results. Although females received significantly lower dosage of levodopa, they had significantly more disabling dyskinesia and worse postural instability. Anxiety, pain, sleep disturbances, and orthostatic symptoms were more frequent among females while sexual dysfunction, apathy, and daytime sleepiness were more severe among males. Women had worse HRQoL than men (EQ-5D index value: 0.620 ± 0.240 versus 0.663 ± 0.229, p = 0.025, and PDQ-39 SI: 27.1 ± 17.0 versus 23.5 ± 15.9, p = 0.010). Based on multiple regression analysis, sex was an independent predictor for HRQoL in PD. Conclusions. Based on our results, female sex is an independent predictor for having worse HRQoL in PD.

Kinetics of Inhibition of Monoamine Oxidase Using Curcumin and Ellagic Acid

Background:

Curcumin and ellagic are the natural polyphenols having a wide range of pharmacological actions. They have been reported to have their use in various neurological disorders.

Objective:

This study was aimed to evaluate the effect of curcumin and ellagic acid on the activity of monoamine oxidase (MAO), the enzyme responsible for metabolism of monoamine neurotransmitters which are pivotal for neuronal development and function.

Materials and Methods:

The in vitro effects of these selected polyphenols on MAO activities in mitochondria isolated from rat brains were examined. Brain mitochondria were assayed for MAO type-B (MAO-B) using benzylamine as substrates. Rat brain mitochondrial MAO preparation was used to study the kinetics of enzyme inhibition using double reciprocal Lineweaver–Burk plot.

Results:

MAO activity was inhibited by curcumin and ellagic acid; however, higher half maximal inhibitory concentrations of curcumin (500.46 nM) and ellagic acid (412.24 nM) were required compared to the known MAO-B inhibitor selegiline. It is observed that the curcumin and ellagic acid inhibit the MAO activity with both the competitive and noncompetitive type of inhibitions.

Conclusions:

Curcumin and ellagic acid can be considered a possible source of MAO inhibitor used in the treatment of Parkinson's and other neurological disorders.

SUMMARY

Monoamine oxidase (MAO) is involved in a variety of neurological disorders including Parkinson's disease (PD)

Curcumin and ellagic acid inhibit the monoamine oxidase activity

Ellagic acid revealed more potent MAO type-B (MAO-B) inhibitory activity than curcumin

Kinetic studies of MAO inhibition using different concentrations of curcumin and ellagic acid were plotted as double reciprocal Lineweaver–Burk plot

The mode of inhibition of both compounds toward MAO-B is mixed (competitive and uncompetitive) type of inhibition with both the competitive and noncompetitive type of inhibitions.

Abbreviations used: MAO: Monoamine oxidase, IC₅₀: Higher half maximal inhibitory concentrations, PD: Parkinson's disease, LB: Lewy bodies, SNpc: Substantia nigra pars compacta, ROS: Reactive oxygen species, SG: Selegiline, DMC: demethoxycurcumin, BDMC: Bisdemethoxycurcumin.

Tracing the trajectory of behavioral impairments and oxidative stress in an animal model of neonatal inflammation

Exposure to early-life inflammation results in time-of-challenge-dependent changes in both brain and behavior. The consequences of this neural and behavioral reprogramming are most often reported in adulthood. However, the trajectory for the expression of these various changes is not well delineated, particularly between the juvenile and adult phases of development. Moreover, interventions to protect against these neurodevelopmental disruptions are rarely evaluated. Here, female Sprague-Dawley rats were housed in either environmental enrichment (EE) or standard care (SC) and their male and female offspring were administered 50 μg/kg i.p. of lipopolysaccharide (LPS) or pyrogen-free saline in a dual-administration neonatal protocol. All animals maintained their respective housing assignments from breeding until the end of the study. LPS exposure on postnatal days (P) 3 and 5 of life resulted in differential expression of emotional and cognitive disruptions and evidence of oxidative stress across development. Specifically, social behavior was reduced in neonatal-treated (n)LPS animals at adolescence (P40), but not adulthood (P70). In contrast, male nLPS rats exhibited intact spatial memory as adolescents which was impaired in later life. Moreover, these males had decreased prefrontal cortex levels of glutathione at P40, which was normalized in adult animals. Notably, EE appeared to offer some protection against the consequences of inflammation on juvenile social behavior and fully prevented reduced glutathione levels in the juvenile prefrontal cortex. Combined, these time-dependent effects provide evidence that early-life inflammation interacts with other developmental variables, specifically puberty and EE, in the expression (and prevention) of select behavioral and molecular programs.