Parkinson's disease as a result of aging

Research on the signaling pathways related to the intervention of traditional Chinese medicine in Parkinson's disease:A literature review

ETHNOPHARMACOLOGICAL RELEVANCE

Parkinson's disease (PD) is the most common progressive neurodegenerative disorder affecting more than 10 million people worldwide and is characterized by the progressive loss of Daergic (DA) neurons in the substantia nigra pars compacta. It has been reported that signaling pathways play a crucial role in the pathogenesis of PD, while the active ingredients of traditional Chinese medicine (TCM) have been found to possess a protective effect against PD. TCM has demonstrated significant potential in mitigating oxidative stress (OS), neuroinflammation, and apoptosis of DA neurons via the regulation of signaling pathways associated with PD.

AIM OF THE REVIEW

This study discussed and analyzed the signaling pathways involved in the occurrence and development of PD and the mechanism of active ingredients of TCM regulating PD via signaling pathways, with the aim of providing a basis for the development and clinical application of therapeutic strategies for TCM in PD.

MATERIALS AND METHODS

With "Parkinson's disease", "Idiopathic Parkinson's Disease", "Lewy Body Parkinson's Disease", "Parkinson's Disease, Idiopathic", "Parkinson Disease, Idiopathic", "Parkinson's disorders", "Parkinsonism syndrome", "Traditional Chinese medicine", "Chinese herbal medicine", "active ingredients", "medicinal plants" as the main keywords, PubMed, Web of Science and other online search engines were used for literature retrieval.

RESULTS

PD exhibits a close association with various signaling pathways, including but not limited to MAPKs, NF-κB, PI3K/Akt, Nrf2/ARE, Wnt/β-catenin, TLR/TRIF, NLRP3, Notch. The therapeutic potential of TCM lies in its ability to regulate these signaling pathways. In addition, the active ingredients of TCM have shown significant effects in improving OS, neuroinflammation, and DA neuron apoptosis in PD.

CONCLUSION

The active ingredients of TCM have unique advantages in regulating PD-related signaling pathways. It is suggested to combine network pharmacology and bioinformatics to study the specific targets of TCM. This not only provides a new way for the prevention and treatment of PD with the active ingredients of TCM, but also provides a scientific basis for the selection and development of TCM preparations.

The Role of IL-6 in Neurodegenerative Disorders

"Neurodegenerative disorder" is an umbrella term for a group of fatal progressive neurological illnesses characterized by neuronal loss and inflammation. Interleukin-6 (IL-6), a pleiotropic cytokine, significantly affects the activities of nerve cells and plays a pivotal role in neuroinflammation. Furthermore, as high levels of IL-6 have been frequently observed in association with several neurodegenerative disorders, it may potentially be used as a biomarker for the progression and prognosis of these diseases. This review summarizes the production and function of IL-6 as well as its downstream signaling pathways. Moreover, we make a comprehensive review on the roles of IL-6 in neurodegenerative disorders and its potential clinical application.

A study of the genotoxicity, fertility and early embryonic development toxicity of rotigotine behenate extended-release microspheres

Continuous dopaminergic stimulation (CDS) has become an important strategy for the development of drugs to treat Parkinson's disease (PD). Rotigotine behenate extended-release microspheres (RBEM) for injection represent a new treatment regime for CDS and are undergoing clinical trials. In this study, we aimed to investigate the effect of RBEM on genotoxicity, fertility and early embryonic development. We used the Ames test, Chinese hamster lung (CHL) cell chromosome aberration test and the mouse bone marrow micronucleus test, to evaluate the genotoxicity of RBEM. These tests were all negative, thus indicating that RBEM did not induce genotoxicity. In reproduction toxicity testing in male rats on obvious findings following intramuscular administration (i.m.) of RBEM at up to 540 mg/kg (P > 0.5), when female rats were administered with RBEM in the dose range of 60 to 540 mg/kg given (i.m.), there were clear effects on fertility and early embryonic development. These results indicated that RBEM could induce toxicity in female rats and exert effect on fertility and early embryonic development stage.

Older adults and individuals with Parkinson's disease control posture along suborthogonal directions that deviate from the traditional anteroposterior and mediolateral directions

A rich and complex temporal structure of variability in postural sway characterizes healthy and adaptable postural control. However, neurodegenerative disorders such as Parkinson's disease, which often manifest as tremors, rigidity, and bradykinesia, disrupt this healthy variability. This study examined postural sway in young and older adults, including individuals with Parkinson's disease, under different upright standing conditions to investigate the potential connection between the temporal structure of variability in postural sway and Parkinsonism. A novel and innovative method called oriented fractal scaling component analysis was employed. This method involves decomposing the two-dimensional center of pressure (CoP) planar trajectories to pinpoint the directions associated with minimal and maximal temporal correlations in postural sway. As a result, it facilitates a comprehensive assessment of the directional characteristics within the temporal structure of sway variability. The results demonstrated that healthy young adults control posture along two orthogonal directions closely aligned with the traditional anatomical anteroposterior (AP) and mediolateral (ML) axes. In contrast, older adults and individuals with Parkinson's disease controlled posture along suborthogonal directions that significantly deviate from the AP and ML axes. These findings suggest that the altered temporal structure of sway variability is evident in individuals with Parkinson's disease and underlies postural deficits, surpassing what can be explained solely by the natural aging process.

Synaptic dysfunction and extracellular matrix dysregulation in dopaminergic neurons from sporadic and E326K-GBA1 Parkinson's disease patients

Parkinson's disease (PD) is a neurodegenerative disease with both genetic and sporadic origins. In this study, we investigated the electrophysiological properties, synaptic activity, and gene expression differences in dopaminergic (DA) neurons derived from induced pluripotent stem cells (iPSCs) of healthy controls, sporadic PD (sPD) patients, and PD patients with E326K-GBA1 mutations. Our results demonstrate reduced sodium currents and synaptic activity in DA neurons derived from PD patients with E326K-GBA1 mutations, suggesting a potential contribution to PD pathophysiology. We also observed distinct electrophysiological alterations in sPD DA neurons, which included a decrease in synaptic currents. RNA sequencing analysis revealed unique dysregulated pathways in sPD neurons and E326K-GBA1 neurons, further supporting the notion that molecular mechanisms driving PD may differ between PD patients. In agreement with our previous reports, Extracellular matrix and Focal adhesion pathways were among the top dysregulated pathways in DA neurons from sPD patients and from patients with E326K-GBA1 mutations. Overall, our study further confirms that impaired synaptic activity is a convergent functional phenotype in DA neurons derived from PD patients across multiple genetic mutations as well as sPD. At the transcriptome level, we find that the brain extracellular matrix is highly involved in PD pathology across multiple PD-associated mutations as well as sPD.

The Synergistic Effect Study of Lipopolysaccharide (LPS) and A53T-α-Synuclein: Intranasal LPS Exposure on the A53T-α-Synuclein Transgenic Mouse Model of Parkinson's Disease

Aging and interactions between genetic and environmental factors are believed to be involved the chronic development of Parkinson's disease (PD). Among PD patients, abnormally aggregated α-synuclein is a major component of the Lewy body. Generally, the intranasal route is believed to be a gate way to the brain, and it assists environmental neurotoxins in entering the brain and is related to anosmia during early PD. The current study applies the chronic intranasal application of lipopolysaccharides (LPS) in 4-, 8-, 12- and 16-month-old A53T-α-synuclein (A53T-α-Syn) transgenic C57BL/6 mice at 2-day intervals for a 2-month period, for evaluating the behavioral, pathological, and biochemical changes and microglial activation in these animals. According to our results, after intranasal administration of LPS, A53T-α-Syn mice showed severe progressive anosmia, hypokinesia, selective dopaminergic (DAergic) neuronal losses, decreased striatal dopamine (DA) level, and enhanced α-synuclein accumulation within the substantia nigra (SN) in an age-dependent way. In addition, we found obvious NF-кB activation, Nurr1 inhibition, IL-1β, and TNF-α generation within the microglia of the SN. Conversely, the wild-type (WT) mice showed mild, whereas A53T-α-Syn mice had moderate PD-like changes among the old mice. This study demonstrated the synergistic effect of intranasal LPS and α-synuclein burden on PD development. Its underlying mechanism may be associated with Nurr1 inhibition within microglia and the amplification of CNS neuroinflammation. The mice with multiple factors, including aging, neuroinflammation, and α-synuclein mutation, have played a significant role in enhancing our understanding of how inflammation and α-synuclein mutation contribute to the neurodegeneration observed in PD.

Differences in brain aging between sexes in Parkinson's disease

Parkinson's disease (PD) is linked to faster brain aging. Male sex is associated with higher prevalence, severe symptoms, and a faster progression rate in PD. There remains a significant gap in understanding the function of sex in the process of brain aging in PD. The structural T1-weighted MRI-driven brain-predicted age difference (i.e., Brain-PAD: the actual age subtracted from the brain-predicted age) was computed in a group of 373 people with PD (mean age ± SD: 61.37 ± 9.81, age range: 33-85, 34% female) from the Parkinson's Progression Marker Initiative database using a robust brain-age estimation framework that was trained on 949 healthy subjects. Linear regression models were used to investigate the association between Brain-PAD and clinical variables in PD, stratified by sex. Males with Parkinson's disease (PD-M) exhibited a significantly higher mean Brain-PAD than their female counterparts (PD-F) (t(256) = 2.50, p = 0.012). In the propensity score-matched PD-M group (PD-M*), Brain-PAD was found to be associated with a decline in general cognition, a worse degree of sleep behavior disorder, reduced visuospatial acuity, and caudate atrophy. Conversely, no significant links were observed between these factors and Brain-PAD in the PD-F group. Having 'older' looking brains in PD-M than PD-F supports the idea that sex plays a vital function in PD, such that the PD mechanism may be different in males and females. This study has the potential to broaden our understanding of dissimilarities in brain aging between sexes in the context of PD.

Immunosenescence as a convergence pathway in neurodegeneration

Immunity refers to the body's defense mechanism to protect itself against illness or to produce antibodies against pathogens. Senescence is a cellular phenomenon that integrates a sustainable growth restriction, other phenotypic abnormalities and including a pro-inflammatory secretome. It is highly involved in regulating developmental stages, tissue homeostasis, and tumor proliferation monitoring. Contemporary experimental reports imply that abolition of senescent cells employing evolved genetic and therapeutic approaches augment the chances of survival and boosts the health span of an individual. Immunosenescence is considered as a process in which dysfunction of the immune system occurs with aging and greatly includes remodeling of lymphoid organs. This in turn causes fluctuations in the immune function of the elderly that has strict relation with the expansion of autoimmune diseases, infections, malignant tumors and neurodegenerative disorders. The interaction of the nervous and immune systems during aging is marked by bi-directional influence and mutual correlation of variations. The enhanced systemic inflammatory condition in the elderly, and the neuronal immune cell activity can be modulated by inflamm-aging and peripheral immunosenescence resulting in chronic low-grade inflammatory processes in the central Nervous system known as neuro-inflammaging. For example, glia excitation by cytokines and glia pro-inflammatory productions contribute significantly to memory injury as well as in acute systemic inflammation, which is associated with high levels of Tumor necrosis factor -α and a rise in cognitive decline. In recent years its role in the pathology of Alzheimer's disease has caught research interest to a large extent. This article reviews the connection concerning the immune and nervous systems and highlights how immunosenescence and inflamm-aging can affect neurodegenerative disorders.

Trends and Treatment Approaches for Complications in Neuroscience Experiments with Monkey Species

Our goal in this manuscript is to advance the assessment and treatment of monkey species in neuroscience research. We hope to begin a discussion and establish baseline data on how complications are identified and treated. We surveyed the neuroscience research community working with monkeys and compiled responses to questions about investigator demographics, assessment of animal wellbeing, treatment choices, and approaches to mitigate risks associated with CNS procedures and promote monkey health and wellbeing. The majority of the respondents had worked with nonhuman primates (NHP) for over 15 y. Identification of procedure-related complications and efficacy of treatment generally rely on common behavioral indices. Treatments for localized inflammatory responses are generally successful, whereas the treatment success for meningitis or meningoencephalitis, abscesses, and hemorrhagic stroke are less successful. Behavioral signs of pain are treated successfully with NSAIDs and opioids. Our future plans are to collate treatment protocols and develop best practices that can be shared across the neuroscience community to improve treatment success rates and animal welfare and therefore science. Human protocols can be used to develop best practices, assess outcomes, and promote further refinements in treatment practices for monkeys to enhance research outcomes.

The Impact of microRNAs on Mitochondrial Function and Immunity: Relevance to Parkinson's Disease

Parkinson's Disease (PD), the second most common neurodegenerative disorder, is characterised by the severe loss of dopaminergic neurons in the Substantia Nigra pars compacta (SNpc) and by the presence of Lewy bodies. PD is diagnosed upon the onset of motor symptoms, such as bradykinesia, resting tremor, rigidity, and postural instability. It is currently accepted that motor symptoms are preceded by non-motor features, such as gastrointestinal dysfunction. In fact, it has been proposed that PD might start in the gut and spread to the central nervous system. Growing evidence reports that the gut microbiota, which has been found to be altered in PD patients, influences the function of the central and enteric nervous systems. Altered expression of microRNAs (miRNAs) in PD patients has also been reported, many of which regulate key pathological mechanisms involved in PD pathogenesis, such as mitochondrial dysfunction and immunity. It remains unknown how gut microbiota regulates brain function; however, miRNAs have been highlighted as important players. Remarkably, numerous studies have depicted the ability of miRNAs to modulate and be regulated by the host's gut microbiota. In this review, we summarize the experimental and clinical studies implicating mitochondrial dysfunction and immunity in PD. Moreover, we gather recent data on miRNA involvement in these two processes. Ultimately, we discuss the reciprocal crosstalk between gut microbiota and miRNAs. Studying the bidirectional interaction of gut microbiome-miRNA might elucidate the aetiology and pathogenesis of gut-first PD, which could lead to the application of miRNAs as potential biomarkers or therapeutical targets for PD.

The antioxidant effects of hedysarum polybotrys polysaccharide in extending lifespan and ameliorating aging-related diseases in Drosophila melanogaster

Hedysarum polybotrys polysaccharide (HPS) is one of the main active ingredients of Hedysarum with many health-beneficial properties, including antioxidant property, immunomodulatory, anti-inflammatory, and anti-tumor. However, the effect of HPS on anti-aging is still unclear. This study was to explore the protective function of HPS on aging and age-related diseases using Drosophila melanogaster. The results demonstrated that HPS supplementation promoted hatchability and prolonged lifespan by enhancing the antioxidative capacity. Administraction of HPS ameliorated age-related symptoms such as imbalanced intestinal homeostasis, sleep disturbances, and beta-amyloid (Aβ) induced Alzheimer's disease (AD) in flies, but did not modulate neurobehavioral deficits in the AD model of tauopathy and the Parkinson's disease (PD) model of Pink1 mutation. Overall, this study reveals that HPS has strong potential in the prevention of aging and age-related diseases, and provided a new candidate for the development of anti-aging drugs.

Redox Imbalance in Neurological Disorders in Adults and Children

Oxygen is a central molecule for numerous metabolic and cytophysiological processes, and, indeed, its imbalance can lead to numerous pathological consequences. In the human body, the brain is an aerobic organ and for this reason, it is very sensitive to oxygen equilibrium. The consequences of oxygen imbalance are especially devastating when occurring in this organ. Indeed, oxygen imbalance can lead to hypoxia, hyperoxia, protein misfolding, mitochondria dysfunction, alterations in heme metabolism and neuroinflammation. Consequently, these dysfunctions can cause numerous neurological alterations, both in the pediatric life and in the adult ages. These disorders share numerous common pathways, most of which are consequent to redox imbalance. In this review, we will focus on the dysfunctions present in neurodegenerative disorders (specifically Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis) and pediatric neurological disorders (X-adrenoleukodystrophies, spinal muscular atrophy, mucopolysaccharidoses and Pelizaeus-Merzbacher Disease), highlighting their underlining dysfunction in redox and identifying potential therapeutic strategies.

Herbal/Natural Compounds Resist Hallmarks of Brain Aging: From Molecular Mechanisms to Therapeutic Strategies

Aging is a complex process of impaired physiological integrity and function, and is associated with increased risk of cardiovascular disease, diabetes, neurodegeneration, and cancer. The cellular environment of the aging brain exhibits perturbed bioenergetics, impaired adaptive neuroplasticity and flexibility, abnormal neuronal network activity, dysregulated neuronal Ca²⁺ homeostasis, accumulation of oxidatively modified molecules and organelles, and clear signs of inflammation. These changes make the aging brain susceptible to age-related diseases, such as Alzheimer's and Parkinson's diseases. In recent years, unprecedented advances have been made in the study of aging, especially the effects of herbal/natural compounds on evolutionarily conserved genetic pathways and biological processes. Here, we provide a comprehensive review of the aging process and age-related diseases, and we discuss the molecular mechanisms underlying the therapeutic properties of herbal/natural compounds against the hallmarks of brain aging.

Disease mechanisms as Subtypes: Mitochondrial and bioenergetic dysfunction

Parkinson disease (PD) is the second most common neurodegenerative disease in the world. Despite its enormous human and societal cost, there is no disease-modifying therapy for PD. This unmet medical need reflects our limited understanding of PD pathogenesis. One of the most important clues comes from the recognition that PD motor symptoms arises from the dysfunction and degeneration of a very select group of neurons in the brain. These neurons have a distinctive set of anatomic and physiologic traits that reflect their role in brain function. These traits elevate mitochondrial stress, potentially making them particularly vulnerable to age, as well as to genetic mutations and environmental toxins linked to PD incidence. In this chapter, the literature supporting this model is outlined, along with gaps in our knowledge base. The translational implications of this hypothesis are then discussed, with a focus on why disease-modification trials have failed to date and what this means for the development of new strategies for altering disease course.

E3 ligase adaptor FBXO7 contributes to ubiquitination and proteasomal degradation of SIRT7 and promotes cell death in response to hydrogen peroxide

Parkinson's disease (PD) is a degenerative disorder of the central nervous system that affects 1% of the population over the age of 60. Although aging is one of the main risk factors for PD, the pathogenic mechanism of this disease remains unclear. Mutations in the F-box-only protein 7 (FBXO7) gene have been previously found to cause early onset autosomal recessive familial PD. FBXO7 is an adaptor protein in the SKP1-Cullin-1-F-box (SCF) E3 ligase complex that facilitates the ubiquitination of substrates. Sirtuin 7 (SIRT7) is an NAD⁺-dependent histone deacetylase that regulates aging and stress responses. In this study, we identified FBXO7 as a novel E3 ligase for SIRT7 that negatively regulates intracellular SIRT7 levels through SCF-dependent Lys-48-linked polyubiquitination and proteasomal degradation. Consequently, we show that FBXO7 promoted the blockade of SIRT7 deacetylase activity, causing an increase in acetylated histone 3 levels at the Lys-18 and Lys-36 residues and the repression of downstream RPS20 gene transcription. Moreover, we demonstrate that treatment with hydrogen peroxide triggered the FBXO7-mediated degradation of SIRT7, leading to mammalian cell death. In particular, the PD-linked FBXO7-R498X mutant, which reduced SCF-dependent E3 ligase activity, did not affect the stability of SIRT7. Collectively, these findings suggest that FBXO7 negatively regulates SIRT7 stability and may suppress the cytoprotective effects of SIRT7 during hydrogen peroxide-induced mammalian cell death.

Neurobiological Mechanisms of Cognitive Decline Correlated with Brain Aging

Cognitive decline has emerged as one of the greatest health threats of old age. Meanwhile, aging is the primary risk factor for Alzheimer's disease (AD) and other prevalent neurodegenerative disorders. Developing therapeutic interventions for such conditions demands a greater understanding of the processes underlying normal and pathological brain aging. Despite playing an important role in the pathogenesis and incidence of disease, brain aging has not been well understood at a molecular level. Recent advances in the biology of aging in model organisms, together with molecular- and systems-level studies of the brain, are beginning to shed light on these mechanisms and their potential roles in cognitive decline. This chapter seeks to integrate the knowledge about the neurological mechanisms of age-related cognitive changes that underlie aging.

Potential application of heat shock proteins as therapeutic targets in Parkinson's disease

Parkinson's disease (PD) is a common chronic neurodegenerative disease, and the heat shock proteins (HSPs) are proved to be of great value for PD. In addition, HSPs can maintain protein homeostasis, degrade and inhibit protein aggregation by properly folding and activating intracellular proteins in PD. This study mainly summarizes the important roles of HSPs in PD and explores their feasibility as targets. We introduced the structural and functional characteristics of HSPs and the physiological functions of HSPs in PD. HSPs can protect neurons from damage by degrading aggregates with three mechanisms, including the aggregation and removing α-Synuclein (α-Syn) aggregates, promotion the autophagy of abnormal proteins, and inhibition the apoptosis of degenerated neurons. This study underscores the importance of HSPs as targets in PD and helps to expand new mechanisms in PD treatment strategies.

DGHNE: network enhancement-based method in identifying disease-causing genes through a heterogeneous biomedical network

The identification of disease-causing genes is critical for mechanistic understanding of disease etiology and clinical manipulation in disease prevention and treatment. Yet the existing approaches in tackling this question are inadequate in accuracy and efficiency, demanding computational methods with higher identification power. Here, we proposed a new method called DGHNE to identify disease-causing genes through a heterogeneous biomedical network empowered by network enhancement. First, a disease-disease association network was constructed by the cosine similarity scores between phenotype annotation vectors of diseases, and a new heterogeneous biomedical network was constructed by using disease-gene associations to connect the disease-disease network and gene-gene network. Then, the heterogeneous biomedical network was further enhanced by using network embedding based on the Gaussian random projection. Finally, network propagation was used to identify candidate genes in the enhanced network. We applied DGHNE together with five other methods into the most updated disease-gene association database termed DisGeNet. Compared with all other methods, DGHNE displayed the highest area under the receiver operating characteristic curve and the precision-recall curve, as well as the highest precision and recall, in both the global 5-fold cross-validation and predicting new disease-gene associations. We further performed DGHNE in identifying the candidate causal genes of Parkinson's disease and diabetes mellitus, and the genes connecting hyperglycemia and diabetes mellitus. In all cases, the predicted causing genes were enriched in disease-associated gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways, and the gene-disease associations were highly evidenced by independent experimental studies.

Dysfunction of the neurovascular unit in brain aging

An emerging concept termed the neurovascular unit (NVU) underlines neurovascular coupling. It has been reported that NVU impairment can result in neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Aging is a complex and irreversible process caused by programmed and damage-related factors. Loss of biological functions and increased susceptibility to additional neurodegenerative diseases are major characteristics of aging. In this review, we describe the basics of the NVU and discuss the effect of aging on NVU basics. Furthermore, we summarize the mechanisms that increase NVU susceptibility to neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Finally, we discuss new treatments for neurodegenerative diseases and methods of maintaining an intact NVU that may delay or diminish aging.

Parkinson's disease-associated, sex-specific changes in DNA methylation at PARK7 (DJ-1), SLC17A6 (VGLUT2), PTPRN2 (IA-2β), and NR4A2 (NURR1) in cortical neurons

Evidence for epigenetic regulation playing a role in Parkinson's disease (PD) is growing, particularly for DNA methylation. Approximately 90% of PD cases are due to a complex interaction between age, genes, and environmental factors, and epigenetic marks are thought to mediate the relationship between aging, genetics, the environment, and disease risk. To date, there are a small number of published genome-wide studies of DNA methylation in PD, but none accounted for cell type or sex in their analyses. Given the heterogeneity of bulk brain tissue samples and known sex differences in PD risk, progression, and severity, these are critical variables to account for. In this genome-wide analysis of DNA methylation in an enriched neuronal population from PD postmortem parietal cortex, we report sex-specific PD-associated methylation changes in PARK7 (DJ-1), SLC17A6 (VGLUT2), PTPRN2 (IA-2β), NR4A2 (NURR1), and other genes involved in developmental pathways, neurotransmitter packaging and release, and axon and neuron projection guidance.

Hypoxia signaling in human health and diseases: implications and prospects for therapeutics

Molecular oxygen (O₂) is essential for most biological reactions in mammalian cells. When the intracellular oxygen content decreases, it is called hypoxia. The process of hypoxia is linked to several biological processes, including pathogenic microbe infection, metabolic adaptation, cancer, acute and chronic diseases, and other stress responses. The mechanism underlying cells respond to oxygen changes to mediate subsequent signal response is the central question during hypoxia. Hypoxia-inducible factors (HIFs) sense hypoxia to regulate the expressions of a series of downstream genes expression, which participate in multiple processes including cell metabolism, cell growth/death, cell proliferation, glycolysis, immune response, microbe infection, tumorigenesis, and metastasis. Importantly, hypoxia signaling also interacts with other cellular pathways, such as phosphoinositide 3-kinase (PI3K)-mammalian target of rapamycin (mTOR) signaling, nuclear factor kappa-B (NF-κB) pathway, extracellular signal-regulated kinases (ERK) signaling, and endoplasmic reticulum (ER) stress. This paper systematically reviews the mechanisms of hypoxia signaling activation, the control of HIF signaling, and the function of HIF signaling in human health and diseases. In addition, the therapeutic targets involved in HIF signaling to balance health and diseases are summarized and highlighted, which would provide novel strategies for the design and development of therapeutic drugs.

Neuroglial Senescence, α-Synucleinopathy, and the Therapeutic Potential of Senolytics in Parkinson’s Disease

Parkinson’s disease (PD) is the most common movement disorder and the second most prevalent neurodegenerative disease after Alzheimer’s disease. Despite decades of research, there is still no cure for PD and the complicated intricacies of the pathology are still being worked out. Much of the research on PD has focused on neurons, since the disease is characterized by neurodegeneration. However, neuroglia has become recognized as key players in the health and disease of the central nervous system. This review provides a current perspective on the interactive roles that α-synuclein and neuroglial senescence have in PD. The self-amplifying and cyclical nature of oxidative stress, neuroinflammation, α-synucleinopathy, neuroglial senescence, neuroglial chronic activation and neurodegeneration will be discussed. Finally, the compelling role that senolytics could play as a therapeutic avenue for PD is explored and encouraged.

Carving the senescent phenotype by the chemical reactivity of catecholamines: An integrative review

Macromolecules damaged by covalent modifications produced by chemically reactive metabolites accumulate in the slowly renewable components of living bodies and compromise their functions. Among such metabolites, catecholamines (CA) are unique, compared with the ubiquitous oxygen, ROS, glucose and methylglyoxal, in that their high chemical reactivity is confined to a limited set of cell types, including the dopaminergic and noradrenergic neurons and their direct targets, which suffer from CA propensities for autoxidation yielding toxic quinones, and for Pictet-Spengler reactions with carbonyl-containing compounds, which yield mitochondrial toxins. The functions progressively compromised because of that include motor performance, cognition, reward-driven behaviors, emotional tuning, and the neuroendocrine control of reproduction. The phenotypic manifestations of the resulting disorders culminate in such conditions as Parkinson's and Alzheimer's diseases, hypertension, sarcopenia, and menopause. The reasons to suspect that CA play some special role in aging accumulated since early 1970-ies. Published reviews address the role of CA hazardousness in the development of specific aging-associated diseases. The present integrative review explores how the bizarre discrepancy between CA hazardousness and biological importance could have emerged in evolution, how much does the chemical reactivity of CA contribute to the senescent phenotype in mammals, and what can be done with it.

The Influence of Aging on the Functional Connectivity of the Human Basal Ganglia

Although basal ganglia (BG) are involved in the motor disorders of aged people, the effect of aging on the functional interaction of BG is not well-known. This work was aimed at studying the influence of aging on the functional connectivity of the motor circuit of BG (BGmC). Thirty healthy volunteers were studied (young-group 26.4 ± 5.7 years old; aged-group 63.1 ± 5.8 years old) with a procedure planned to prevent the spurious functional connectivity induced by the closed-loop arrangement of the BGmC. BG showed different functional interactions during the inter-task intervals and when subjects did not perform any voluntary task. Aging induced marked changes in the functional connectivity of the BGmC during these inter-task intervals. The finger movements changed the functional connectivity of the BG, these modifications were also different in the aged-group. Taken together, these data show a marked effect of aging on the functional connectivity of the BGmC, and these effects may be at the basis of the motor handicaps of aged people during the execution of motor-tasks and when they are not performing any voluntary motor task.

Cerebral topography of vesicular cholinergic transporter changes in neurologically intact adults: A [18F]FEOBV PET study

Acetylcholine plays a major role in brain cognitive and motor functions with regional cholinergic terminal loss common in several neurodegenerative disorders. We describe age-related declines of regional cholinergic neuron terminal density in vivo using the positron emission tomography (PET) ligand [¹⁸F](–)5-Fluoroethoxybenzovesamicol ([¹⁸F] FEOBV), a vesamicol analogue selectively binding to the vesicular acetylcholine transporter (VAChT). A total of 42 subjects without clinical evidence of neurologic disease (mean 50.55 [range 20–80] years, 24 Male/18 Female) underwent [¹⁸F]FEOBV brain PET imaging. We used SPM based voxel-wise statistical analysis to perform whole brain voxel-based parametric analysis (family-wise error corrected, FWE) and to also extract the most significant clusters of regions correlating with aging with gender as nuisance variable. Age-related VAChT binding reductions were found in primary sensorimotor cortex, visual cortex, caudate nucleus, anterior to mid-cingulum, bilateral insula, para-hippocampus, hippocampus, anterior temporal lobes/amygdala, dorsomedial thalamus, metathalamus, and cerebellum (gender and FWE-corrected, P < 0.05). These findings show a specific topographic pattern of regional vulnerability of cholinergic nerve terminals across multiple cholinergic systems accompanying aging.

WATSU therapy for individuals with Parkinson's disease to improve quality of sleep and quality of life: A randomized controlled study

BACKGROUND

and Purpose: Sleep disorders are one of the most frequent non-motor symptoms of Parkinson's disease (PD). This study aimed to verify whether adding WATSU to land-based therapy leads to additional beneficial therapeutic effects regarding quality of sleep and quality of life (QOL) in individuals with PD.

MATERIALS & METHODS

A randomized control trial design was used. Participants completed nine-week interventions. The control group (CG) received land-based therapy, while the intervention group (IG) received the same land-based therapy and additionally WATSU. Sleep quality and QOL were measured at baseline and post-interventions by Pittsburgh Sleep Quality Index and Nottingham Health Profile, respectively.

RESULTS

Twenty-eight participants completed the study. In contrast to CG, the IG presented with significant improvements in both, quality of sleep and QOL (p < 0.001).

CONCLUSION

WATSU has the potential to be an attractive adjunct therapy for producing positive health impacts regarding sleep quality, which may translate to an overall improvement in QOL of individuals with PD.

Bioenergetic Impairment in the Neuro-Glia-Vascular Unit: An Emerging Physiopathology during Aging

An emerging concept termed the "neuro-glia-vascular unit" (NGVU) has been established in recent years to understand the complicated mechanism of multicellular interactions among vascular cells, glial cells, and neurons. It has been proverbially reported that the NGVU is significantly associated with neurodegenerative disorders, such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). Physiological aging is an inevitable progression associated with oxidative damage, bioenergetic alterations, mitochondrial dysfunction, and neuroinflammation, which is partially similar to the pathology of AD. Thus, senescence is regarded as the background for the development of neurodegenerative diseases. With the exacerbation of global aging, senescence is an increasingly serious problem in the medical field. In this review, the coupling of each component, including neurons, glial cells, and vascular cells, in the NGVU is described in detail. Then, various mechanisms of age-dependent impairment in each part of the NGVU are discussed. Moreover, the potential bioenergetic alterations between different cell types in the NGVU are highlighted, which seems to be an emerging physiopathology associated with the aged brain. Bioenergetic intervention in the NGVU may be a new direction for studies on delaying or diminishing aging in the future.

α-Synuclein antisense transcript SNCA-AS1 regulates synapses- and aging-related genes suggesting its implication in Parkinson's disease

SNCA protein product, α‐synuclein, is widely renowned for its role in synaptogenesis and implication in both aging and Parkinson's disease (PD), but research efforts are still needed to elucidate its physiological functions and mechanisms of regulation. In this work, we aim to characterize SNCA‐AS1, antisense transcript to the SNCA gene, and its implications in cellular processes. The overexpression of SNCA‐AS1 upregulates both SNCA and α‐synuclein and, through RNA‐sequencing analysis, we investigated the transcriptomic changes of which both genes are responsible. We highlight how they impact neurites' extension and synapses' biology, through specific molecular signatures. We report a reduced expression of markers associated with synaptic plasticity, and we specifically focus on GABAergic and dopaminergic synapses, for their relevance in aging processes and PD, respectively. A reduction in SNCA‐AS1 expression leads to the opposite effect. As part of this signature is co‐regulated by the two genes, we discriminate between functions elicited by genes specifically altered by SNCA‐AS1 or SNCA's overexpression, observing a relevant role for SNCA‐AS1 in synaptogenesis through a shared molecular signature with SNCA. We also highlight how numerous deregulated pathways are implicated in aging‐related processes, suggesting that SNCA‐AS1 could be a key player in cellular senescence, with implications for aging‐related diseases. Indeed, the upregulation of SNCA‐AS1 leads to alterations in numerous PD‐specific genes, with an impact highly comparable to that of SNCA's upregulation. Our results show that SNCA‐AS1 elicits its cellular functions through the regulation of SNCA, with a specific modulation of synaptogenesis and senescence, presenting implications in PD.

Impact of α-synuclein spreading on the nigrostriatal dopaminergic pathway depends on the onset of the pathology

Misfolded α‐synuclein spreads along anatomically connected areas through the brain, prompting progressive neurodegeneration of the nigrostriatal pathway in Parkinson's disease. To investigate the impact of early stage seeding and spreading of misfolded α‐synuclein along with the nigrostriatal pathway, we studied the pathophysiologic effect induced by a single acute α‐synuclein preformed fibrils (PFFs) inoculation into the midbrain. Further, to model the progressive vulnerability that characterizes the dopamine (DA) neuron life span, we used two cohorts of mice with different ages: 2‐month‐old (young) and 5‐month‐old (adult) mice. Two months after α‐synuclein PFFs injection, we found that striatal DA release decreased exclusively in adult mice. Adult DA neurons showed an increased level of pathology spreading along with the nigrostriatal pathway accompanied with a lower volume of α‐synuclein deposition in the midbrain, impaired neurotransmission, rigid DA terminal composition, and less microglial reactivity compared with young neurons. Notably, preserved DA release and increased microglial coverage in the PFFs‐seeded hemisphere coexist with decreased large‐sized terminal density in young DA neurons. This suggests the presence of a targeted pruning mechanism that limits the detrimental effect of α‐synuclein early spreading. This study suggests that the impact of the pathophysiology caused by misfolded α‐synuclein spreading along the nigrostriatal pathway depends on the age of the DA network, reducing striatal DA release specifically in adult mice.

Astrocytes and retrograde degeneration of nigrostriatal dopaminergic neurons in Parkinson's disease: removing axonal debris

Objective

The dopaminergic nigrostriatal neurons (DA cells) in healthy people present a slow degeneration with aging, which produces cellular debris throughout life. About 2%–5% of people present rapid cell degeneration of more than 50% of DA cells, which produces Parkinson’s disease (PD). Neuroinflammation accelerates the cell degeneration and may be critical for the transition between the slow physiological and the rapid pathological degeneration of DA cells, particularly when it activates microglial cells of the medial forebrain bundle near dopaminergic axons. As synaptic debris produced by DA cell degeneration may trigger the parkinsonian neuroinflammation, this study investigated the removal of axonal debris produced by retrograde degeneration of DA cells, paying particular attention to the relative roles of astrocytes and microglia.

Methods

Rats and mice were injected in the lateral ventricles with 6-hydroxydopamine, inducing a degeneration of dopaminergic synapses in the striatum which was not accompanied by non-selective tissue damage, microgliosis or neuroinflammation. The possible retrograde degeneration of dopaminergic axons, and the production and metabolization of DA-cell debris were studied with immunohistochemical methods and analyzed in confocal and electron microscopy images.

Results

The selective degeneration of dopaminergic synapses in the striatum was followed by a retrograde degeneration of dopaminergic axons whose debris was found within spheroids of the medial forebrain bundle. These spheroids retained mitochondria and most (e.g., tyrosine hydroxylase, the dopamine transporter protein, and amyloid precursor protein) but not all (e.g., α-synuclein) proteins of the degenerating dopaminergic axons. Spheroids showed initial (autophagosomes) but not late (lysosomes) components of autophagy (incomplete autophagy). These spheroids were penetrated by astrocytic processes of the medial forebrain bundle, which provided the lysosomes needed to continue the degradation of dopaminergic debris. Finally, dopaminergic proteins were observed in the cell somata of astrocytes. No microgliosis or microglial phagocytosis of debris was observed in the medial forebrain bundle during the retrograde degeneration of dopaminergic axons.

Conclusions

The present data suggest a physiological role of astrocytic phagocytosis of axonal debris for the medial forebrain bundle astrocytes, which may prevent the activation of microglia and the spread of retrograde axonal degeneration in PD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40035-021-00262-1.

Astrocytes, a Promising Opportunity to Control the Progress of Parkinson's Disease

At present, there is no efficient treatment to prevent the evolution of Parkinson’s disease (PD). PD is generated by the concurrent activity of multiple factors, which is a serious obstacle for the development of etio-pathogenic treatments. Astrocytes may act on most factors involved in PD and the promotion of their neuroprotection activity may be particularly suitable to prevent the onset and progression of this basal ganglia (BG) disorder. The main causes proposed for PD, the ability of astrocytes to control these causes, and the procedures that can be used to promote the neuroprotective action of astrocytes will be commented upon, here.

The Role of Vitamins in Neurodegenerative Disease: An Update

Acquiring the recommended daily allowance of vitamins is crucial for maintaining homeostatic balance in humans and other animals. A deficiency in or dysregulation of vitamins adversely affects the neuronal metabolism, which may lead to neurodegenerative diseases. In this article, we discuss how novel vitamin-based approaches aid in attenuating abnormal neuronal functioning in neurodegeneration-based brain diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis, and Prion disease. Vitamins show their therapeutic activity in Parkinson's disease by antioxidative and anti-inflammatory activity. In addition, different water- and lipid-soluble vitamins have also prevented amyloid beta and tau pathology. On the other hand, some results also show no correlation between vitamin action and the prevention of neurodegenerative diseases. Some vitamins also exhibit toxic activity too. This review discusses both the beneficial and null effects of vitamin supplementation for neurological disorders. The detailed mechanism of action of both water- and lipid-soluble vitamins is addressed in the manuscript. Hormesis is also an essential factor that is very helpful to determine the effective dose of vitamins. PubMed, Google Scholar, Web of Science, and Scopus were employed to conduct the literature search of original articles, review articles, and meta-analyses.

Heterogeneity of prodromal Parkinson symptoms in siblings of Parkinson disease patients

A prodromal phase of Parkinson's disease (PD) may precede motor manifestations by decades. PD patients' siblings are at higher risk for PD, but the prevalence and distribution of prodromal symptoms are unknown. The study objectives were (1) to assess motor and non-motor features estimating prodromal PD probability in PD siblings recruited within the European PROPAG-AGEING project; (2) to compare motor and non-motor symptoms to the well-established DeNoPa cohort. 340 PD siblings from three sites (Bologna, Seville, Kassel/Goettingen) underwent clinical and neurological evaluations of PD markers. The German part of the cohort was compared with German de novo PD patients (dnPDs) and healthy controls (CTRs) from DeNoPa. Fifteen (4.4%) siblings presented with subtle signs of motor impairment, with MDS-UPDRS-III scores not clinically different from CTRs. Symptoms of orthostatic hypotension were present in 47 siblings (13.8%), no different to CTRs (p = 0.072). No differences were found for olfaction and overall cognition; German-siblings performed worse than CTRs in visuospatial-executive and language tasks. 3/147 siblings had video-polysomnography-confirmed REM sleep behavior disorder (RBD), none was positive on the RBD Screening Questionnaire. 173/300 siblings had <1% probability of having prodromal PD; 100 between 1 and 10%, 26 siblings between 10 and 80%, one fulfilled the criteria for prodromal PD. According to the current analysis, we cannot confirm the increased risk of PD siblings for prodromal PD. Siblings showed a heterogeneous distribution of prodromal PD markers and probability. Additional parameters, including strong disease markers, should be investigated to verify if these results depend on validity and sensitivity of prodromal PD criteria, or if siblings' risk is not elevated.

Brain age and Alzheimer's-like atrophy are domain-specific predictors of cognitive impairment in Parkinson's disease

Recently, it was shown that patients with Parkinson's disease (PD) who exhibit an "Alzheimer's disease (AD)-like" pattern of brain atrophy are at greater risk for future cognitive decline. This study aimed to investigate whether this association is domain-specific and whether atrophy associated with brain aging also relates to cognitive impairment in PD. SPARE-AD, an MRI index capturing AD-like atrophy, and atrophy-based estimates of brain age were computed from longitudinal structural imaging data of 178 PD patients and 84 healthy subjects from the LANDSCAPE cohort. All patients underwent an extensive neuropsychological test battery. Patients diagnosed with mild cognitive impairment or dementia were found to have higher SPARE-AD scores as compared to patients with normal cognition and healthy controls. All patient groups showed increased brain age. SPARE-AD predicted impairment in memory, language and executive functions, whereas advanced brain age was associated with deficits in attention and working memory. Data suggest that SPARE-AD and brain age are differentially related to domain-specific cognitive decline in PD. The underlying pathomechanisms remain to be determined.

Negative Effects of COVID-19 Stay-at-Home Mandates on Physical Intervention Outcomes: A Preliminary Study

BACKGROUND

Due to the COVID-19 pandemic, beneficial physical intervention classes for individuals with Parkinson's disease (PD) were cancelled.

OBJECTIVE

To understand effects of the COVID-19 stay-at-home mandate and the inability to participate in recommended and structured physical interventions as a consequence of these mandates, specifically designed mobile assessments were used that collected both self-reporting information and objective task-based metrics of neurocognitive functions to assess symptom changes for individuals with PD.

METHODS

Self-reporting questionnaires focusing on overall quality of life (e.g., when individuals typically feel at their best, changes in activity levels, and symptom progression) were given to all individuals (n = 28). In addition, mobile-based neurocognitive assessments were administered to a subset of the population (n = 8) to quantitatively assess changes due to COVID-19 restrictions.

RESULTS

The highest self-reported factors in which individuals denoted feeling their best were after exercise (67.86%) and being in a comfortable and supportive environment (60.71%). Objective measures found overall duration of physical activity during the stay-at-home mandate decreased significantly (p = 0.022). With the lack of overall activity, 82.14%of individuals self-reported having at least one symptom that worsened moderately or higher. Further testing, using mobile-based assessments, showed average completion times of functional tasks increased, taking about 2.1 times longer, while accuracy metrics showed overall degradation.

CONCLUSION

Although the COVID-19 stay-at-home mandate was intended to help protect individuals at high risk from coming into contact with the virus, it also prevented individuals from receiving recommended supervised exercise interventions resulting in significant negative effects in social well-being and across motor and speech neurocognitive tasks for individuals with PD.

Analysis of mitochondrial regulatory transcripts in publicly available datasets with validation in placentae from pre-term, post-term and fetal growth restriction pregnancies

INTRODUCTION

The human placenta has a defined lifespan and placental aging is a key feature as pregnancy progresses. Placental aging and mitochondrial dysfunction are known to play a key role in pregnancy pathophysiology. Premature aging of the placenta has also been linked with placental dysfunction resulting in poor fetal development and premature birth.

METHODS

The expression of key mitochondrial-related genes were analysed in a series of publicly available databases then expression changes were validated in placental samples collected from term, pre-term, post-term pregnancies and pregnancies complicated by fetal growth restriction (FGR). Gene and protein expression levels of MFN1, MFN2, TFAM, TOMM20, OPA3 and SIRT4 were measured in placental tissues via qPCR and western blotting.

RESULTS

Initial analysis found that key mitochondrial transcripts related to biogenesis, bioenergetics and mitophagy clustered by pregnancy trimester. A refined list of 13 mitochondrial-related genes were investigated in additional external datasets of pregnancy complications. In the new cohort, protein expression of MFN1 was decreased in FGR and MFN2 is decreased in post-term placenta. Analysis of placental tissues revealed that TOMM20 gene and protein expression was altered in FGR and post-term placenta.

DISCUSSION

MFN1 and MFN2 play a major role in mitochondrial dynamics, and alterations in these markers have been highlighted in early unexplained miscarriage. TOMM20 is an importer protein that plays a major role in mitophagy and changes have also been identified in age-related diseases. Significant changes in MFN1, MFN2 and TOMM20 indicate that mitochondrial regulators play a critical role in placental aging and placental pathophysiology.

Hypoxia-Inducible Factor (HIF) in Ischemic Stroke and Neurodegenerative Disease

Hypoxia is one of the most common pathological conditions, which can be induced by multiple events, including ischemic injury, trauma, inflammation, tumors, etc. The body's adaptation to hypoxia is a highly important phenomenon in both health and disease. Most cellular responses to hypoxia are associated with a family of transcription factors called hypoxia-inducible factors (HIFs), which induce the expression of a wide range of genes that help cells adapt to a hypoxic environment. Basic mechanisms of adaptation to hypoxia, and particularly HIF functions, have being extensively studied over recent decades, leading to the 2019 Nobel Prize in Physiology or Medicine. Based on their pivotal physiological importance, HIFs are attracting increasing attention as a new potential target for treating a large number of hypoxia-associated diseases. Most of the experimental work related to HIFs has focused on roles in the liver and kidney. However, increasing evidence clearly demonstrates that HIF-based responses represent an universal adaptation mechanism in all tissue types, including the central nervous system (CNS). In the CNS, HIFs are critically involved in the regulation of neurogenesis, nerve cell differentiation, and neuronal apoptosis. In this mini-review, we provide an overview of the complex role of HIF-1 in the adaptation of neurons and glia cells to hypoxia, with a focus on its potential involvement into various neuronal pathologies and on its possible role as a novel therapeutic target.

Drosophila acquires seconds-scale rhythmic behavior

Detection of the temporal structure of stimuli is crucial for prediction. While perception of interval timing is relevant for immediate behavioral adaptations, it has scarcely been investigated, especially in invertebrates. Here, we examined whether the fruit fly, Drosophila melanogaster, can acquire rhythmic behavior in the range of seconds. To this end, we developed a novel temporal conditioning paradigm utilizing repeated electric shocks. Combined automatic behavioral annotation and time-frequency analysis revealed that behavioral rhythms continued after cessation of the shocks. Furthermore, we found that aging impaired interval timing. This study thus not only demonstrates the ability of insects to acquire behavioral rhythms of a few seconds, but highlights a life-course decline of temporal coordination, which is also common in mammals.

Nurr1 repression mediates cardinal features of Parkinson's disease in α-synuclein transgenic mice

Duplication/triplication mutations of the SNCA locus, encoding alpha-synuclein (ASYN), and loss of function mutations in Nurr1, a nuclear receptor guiding midbrain dopaminergic neuron development, are associated with familial Parkinson’s disease (PD). As we age, the expression levels of these two genes in midbrain dopaminergic neurons follow opposite directions and ASYN expression increases while the expression of Nurr1 decreases. We investigated the effect of ASYN and Nurr1 age-related expression alterations in the pathogenesis of PD by coupling Nurr1 hemizygous with ASYN(s) (heterozygote) or ASYN(d) (homozygote) transgenic mice. ASYN(d)/Nurr1+/− (2-hit) mice, contrary to the individual genetic traits, developed phenotypes consistent with dopaminergic dysfunction. Aging ‘2-hit’ mice manifested kyphosis, severe rigid paralysis, L-DOPA responsive movement impairment and cachexia and died prematurely. Pathological abnormalities of phenotypic mice included SN neuron degeneration, extensive neuroinflammation and enhanced ASYN aggregation. Mice with two wt Nurr1 alleles [ASYN(d)/Nurr1+/+] or with reduced ASYN load [ASYN(s)/Nurr1+/−] did not develop the phenotype or pathology. Critically, we found that aging ASYN(d), in contrast to ASYN(s), mice suppress Nurr1-protein levels in a brain region–specific manner, which in addition to Nurr1 hemizygosity is necessary to instigate PD pathogenesis. Our experiments demonstrate that ASYN-dependent PD-related pathophysiology is mediated at least in part by Nurr1 down-regulation.

Group singing improves quality of life for people with Parkinson's: an international study

Objectives: Group singing has been reported to enhance quality of life (QoL) and mental health in older people. This paper explored whether there are differences in the effects of group singing intervention on people with Parkinson's (PwPs) in Australia, UK and South Korea.Methods: The study included PwPs (N = 95; mean age = 70.26; male 45%) who participated in a standardised 6-month weekly group singing programme. Parkinson's health-related QoL measure (PDQ39) and mental health assessment (DASS) were administered at baseline and follow-up. ANOVAs were performed with significance set as p < .05.Results: ANOVAs revealed main effects of Time on the Stigma and Social Support subscales of PDQ39; both showed a small but significant improvement over time. However, the social support reduction was moderated by country; social support was improved only in South Korean participants. The reduction in stigma was greater than previously reported minimal clinically important differences, as was the social support reduction in South Korean participants. In terms of mental health, ANOVAs revealed that the scores of Anxiety and Stress domains of DASS significantly decreased from pre-test to post-test with small effect sizes.Conclusion: This first international singing study with PwPs demonstrated that group singing can reduce stigma, anxiety and stress and enhance social support in older adults living with Parkinson's. The findings are encouraging and warrant further research using more robust designs.

LRRK2 at the Crossroad of Aging and Parkinson's Disease

Parkinson's disease (PD) is a heterogeneous neurodegenerative disease characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta and the widespread occurrence of proteinaceous inclusions known as Lewy bodies and Lewy neurites. The etiology of PD is still far from clear, but aging has been considered as the highest risk factor influencing the clinical presentations and the progression of PD. Accumulating evidence suggests that aging and PD induce common changes in multiple cellular functions, including redox imbalance, mitochondria dysfunction, and impaired proteostasis. Age-dependent deteriorations in cellular dysfunction may predispose individuals to PD, and cellular damages caused by genetic and/or environmental risk factors of PD may be exaggerated by aging. Mutations in the LRRK2 gene cause late-onset, autosomal dominant PD and comprise the most common genetic causes of both familial and sporadic PD. LRRK2-linked PD patients show clinical and pathological features indistinguishable from idiopathic PD patients. Here, we review cellular dysfunctions shared by aging and PD-associated LRRK2 mutations and discuss how the interplay between the two might play a role in PD pathologies.

Inflammatory Responses to Monomeric and Aggregated α-Synuclein in Peripheral Blood of Parkinson Disease Patients

To investigate whether different forms of α-synuclein (α-syn) proteins can induce inflammation and activate the NLRP3 inflammasome, we stimulated with monomeric or aggregated α-syn peripheral blood mononuclear cells of Parkinson disease (PD) patients and age- and sex-matched healthy controls (HC). ASC-speck formation, i.e., the intracellular generation of functionally active inflammasome complexes, as well as the production of inflammasome-related [caspase-1, interleukin 1β (IL-18), and IL-1β], and pro–IL-6, or anti–IL-10 inflammatory cytokines were evaluated. Gastrointestinal permeability, suggested to be altered in PD, was also investigated by measuring plasma concentration of lipopolysaccharide (LPS) and I-FABP (fatty acid–binding protein). ASC-speck expression, as well as IL-18 and caspase-1 production and LPS and I-FABP plasma concentration, was comparable in PD and HC, indicating that α-syn does not stimulate the NLRP3 inflammasome and that PD does not associate with alterations of intestinal permeability. Interestingly, though, IL-1β and IL-6 production was increased, whereas that of IL-10 was reduced in α-syn–stimulated cells of PD compared to HC, suggesting that PD-associated neuroinflammation is not the consequence of the activation of the NLRP3 inflammasome but rather of an imbalance between proinflammatory and anti-inflammatory cytokines.

p53-mediated ferroptosis is required for 1-methyl-4-phenylpyridinium-induced senescence of PC12 cells

Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra and striatum. Aging is the most important risk factor of PD. Ferroptosis is an iron-dependent form of cell death associated with PD. However, it is not clear whether ferroptosis accelerates PD by promoting cellular senescence. This study investigated the mechanism of 1-methyl-4-phenylpyridinium (MPP⁺) -induced PC12 cells injury. We found that MPP⁺ induced cell senescence with increased β-galactosidase activity and the expression of p53, p21 and p16 activation in cells. In addition, MPP⁺ treatment showed smaller mitochondria and increased membrane density, downregulation of ferritin heavy chain 1 expression and upregulation of acyl-CoA synthetase long chain family member 4 expression, and enhanced levels of oxidative stress, which were important characteristics of ferroptosis. Ferrostatin-1 (Fer-1), a ferroptosis inhibitor, was tested to eliminate MPP⁺-induced cell senescence. Fer-1 downregulated the expression of p53 and upregulated the expression of solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase-4 (GPX4) in MPP⁺-induced ferroptosis. Inhibition of p53 eliminated cell senescence by upregulation the expression of of SLC7A11 and GPX4. Thus, these results suggest that MPP⁺ induces senescence in PC12 cells via the p53/ SLC7A11/ GPX4 signaling pathway in the ferroptosis regulation mechanism.

[Age-related differences in sleep disturbances in rat models of preclinical Parkinson's disease]

OBJECTIVE

To describe the changes in temporal characteristics of sleep-wake cycle, which can serve as non-motor manifestations of an early stage of Parkinson's disease (PD), using the model of preclinical PD in rats of two age groups.

MATERIAL AND METHODS

A prolonged (up to 21 days) model of preclinical PD in middle-aged (7-8 month) and aged (19-20 month) rats was created. The model was based on cumulative inhibition of proteasomal system of the brain caused by intranasal administration of lactacystin, a specific proteasome inhibitor. Polysomnographic data were recorded daily using telemetric Dataquest A.R.T. System (DSI, USA) in unrestrained animals.

RESULTS AND CONCLUSION

Aging was accompanied with increased sleepiness during the active (dark) phase of the day (as was implied by a two-fold increase in the total time of drowsiness) and with 1.5-fold growth of light sleep during the inactive phase of the day. A common feature of sleep disturbances in the model of preclinical PD in both middle-aged and aged rats was hypersomnia during the active phase of the day. It was suggested to be similar to the excessive daytime sleepiness in humans. Hypersomnolence was more pronounced in aged rats because it added to sleepiness developing with aging. In both age groups, the model of preclinical PD was also associated with a decrease in EEG delta power during slow-wave sleep. It is considered dangerous because it might represent the decrease in protein synthesis rate and the weakening of restorative processes in neurons, occurring with the prolonged inhibition of proteasomal system of the brain. Sleep disturbances, identified the model of preclinical PD in rats of different age, may be recommended for clinical validation as low-cost early signs indicating the initial stage of PD.

The intracellular renin-angiotensin system: Friend or foe. Some light from the dopaminergic neurons

The renin-angiotensin system (RAS) is one of the oldest hormone systems in vertebrate phylogeny. RAS was initially related to regulation of blood pressure and sodium and water homeostasis. However, local or paracrine RAS were later identified in many tissues, including brain, and play a major role in their physiology and pathophysiology. In addition, a major component, ACE2, is the entry receptor for SARS-CoV-2. Overactivation of tissue RAS leads several oxidative stress and inflammatory processes involved in aging-related degenerative changes. In addition, a third level of RAS, the intracellular or intracrine RAS (iRAS), with still unclear functions, has been observed. The possible interaction between the intracellular and extracellular RAS, and particularly the possible deleterious or beneficial effects of the iRAS activation are controversial. The dopaminergic system is particularly interesting to investigate the RAS as important functional interactions between dopamine and RAS have been observed in the brain and several peripheral tissues. Our recent observations in mitochondria and nucleus of dopaminergic neurons may clarify the role of the iRAS. This may be important for the developing of new therapeutic strategies, since the effects on both extracellular and intracellular RAS must be taken into account, and perhaps better understanding of COVID-19 cell mechanisms.