The role of parkin in familial and sporadic Parkinson's disease

Allosteric Activation of SIRT1 by 2,4-Dihydroxy-azaflavanone Averts MPP+-Mediated Dysfunction in Mitochondrial Biogenesis and Bioenergetics: Implications for Parkinson's Disease

Parkinson's disease (PD) is a complex neurodegenerative disorder that affects dopamine neurons of the substantia nigra pars compacta (SNpc), resulting in motor dysfunction. Among the pathways examined, mitochondria and α-synuclein were found to play a major role in the disease progression. Hence, several attempts are being made to restore mitochondrial bioenergetics or protein aggregation pathways as disease-modifying strategies. Our earlier studies reported the protective effect of 2,4-dihydroxy-azaflavanone (azaflavanone) in a transgenic Drosophila fly model of PD. In the present study, we found that azaflavanone acts as an allosteric activator of SIRT1 in both cell-free and cell-based systems and the effects were more pronounced as compared to resveratrol. Also, azaflavanone appears to interact selectively with SIRT1 as other SIRTs such as SIRT3 and SIRT6 did not exhibit any gross changes in cellular thermal shift assay (CETSA). Molecular docking studies depicted a higher docking score with azaflavanone than with resveratrol. Further, N27 cells treated with azaflavanone exhibited a dose-dependent increase in the mitotracker staining, mtDNA/nuclear DNA ratio, and also mitochondrial bioenergetics. The observed effects appear to be due to the activation of SIRT1, as evidenced by an increase in the expression of PGC-1α and TFAM, which are the downstream targets of SIRT1. Lastly, the Parkinsonian mimic MPP+-induced disturbance in the mitochondrial membrane potential, mitochondrial bioenergetics, and biogenesis were ameliorated by azaflavanone. Overall, our findings indicate that azaflavanone, being an antioxidant and an allosteric activator of SIRT1, is a promising compound for ameliorating the pathophysiology of PD.

Precision Medicine in Parkinson's Disease Using Induced Pluripotent Stem Cells

Parkinson's disease (PD) is one of the most devastating neurological diseases; however, there is no effective cure yet. The availability of human induced pluripotent stem cells (iPSCs) provides unprecedented opportunities to understand the pathogenic mechanism and identification of new therapy for PD. Here a new model system of PD, including 2D human iPSC-derived midbrain dopaminergic (mDA) neurons, 3D iPSC-derived midbrain organoids (MOs) with cellular complexity, and more advanced microphysiological systems (MPS) with 3D organoids, is introduced. It is believed that successful integrations and applications of iPSC, organoid, and MPS technologies can bring new insight on PD's pathogenesis that will lead to more effective treatments for this debilitating disease.

Diverse Functions of Parkin in Midbrain Dopaminergic Neurons

Parkinson's disease (PD) is characterized by preferential degeneration of midbrain dopaminergic neurons that contributes to its typical clinical manifestation. Mutations in the parkin gene (PARK2) represent a relatively common genetic cause of early onset PD. Parkin has been implicated in PINK1-dependent mitochondrial quantity control by targeting dysfunctional mitochondria to lysosomes via mitophagy. Recent evidence suggests that parkin can be activated in PINK1-independent manner to regulate synaptic function in human dopaminergic neurons. Neuronal activity triggers CaMKII-mediated activation of parkin and its recruitment to synaptic vesicles where parkin promotes binding of synaptojanin-1 to endophilin A1 and facilitates vesicle endocytosis. In PD patient neurons, disruption of this pathway on loss of parkin leads to defective recycling of synaptic vesicles and accumulation of toxic oxidized dopamine that at least in part explains preferential vulnerability of midbrain dopaminergic neurons. These findings suggest a convergent mechanism for PD-linked mutations in parkin, synaptojanin-1, and endophilin A1 and highlight synaptic dysfunction as an early pathogenic event in PD. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

DNA methylation patterns in the frontal lobe white matter of multiple system atrophy, Parkinson's disease, and progressive supranuclear palsy: a cross-comparative investigation

Multiple system atrophy (MSA) is a rare neurodegenerative disease characterized by neuronal loss and gliosis, with oligodendroglial cytoplasmic inclusions (GCIs) containing α-synuclein being the primary pathological hallmark. Clinical presentations of MSA overlap with other parkinsonian disorders, such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and progressive supranuclear palsy (PSP), posing challenges in early diagnosis. Numerous studies have reported alterations in DNA methylation in neurodegenerative diseases, with candidate loci being identified in various parkinsonian disorders including MSA, PD, and PSP. Although MSA and PSP present with substantial white matter pathology, alterations in white matter have also been reported in PD. However, studies comparing the DNA methylation architectures of white matter in these diseases are lacking. We therefore aimed to investigate genome-wide DNA methylation patterns in the frontal lobe white matter of individuals with MSA (n = 17), PD (n = 17), and PSP (n = 16) along with controls (n = 15) using the Illumina EPIC array, to identify shared and disease-specific DNA methylation alterations. Genome-wide DNA methylation profiling of frontal lobe white matter in the three parkinsonian disorders revealed substantial commonalities in DNA methylation alterations in MSA, PD, and PSP. We further used weighted gene correlation network analysis to identify disease-associated co-methylation signatures and identified dysregulation in processes relating to Wnt signaling, signal transduction, endoplasmic reticulum stress, mitochondrial processes, RNA interference, and endosomal transport to be shared between these parkinsonian disorders. Our overall analysis points toward more similarities in DNA methylation patterns between MSA and PD, both synucleinopathies, compared to that between MSA and PD with PSP, which is a tauopathy. Our results also highlight several shared DNA methylation changes and pathways indicative of converging molecular mechanisms in the white matter contributing toward neurodegeneration in all three parkinsonian disorders.

Therapeutic Implications and Regulations of Protein Post-translational Modifications in Parkinsons Disease

Parkinsons disease (PD) is a neurodegenerative disorder characterized by dopaminergic neuron loss and alpha-synuclein aggregation. This comprehensive review examines the intricate role of post-translational modifications (PTMs) in PD pathogenesis, focusing on DNA methylation, histone modifications, phosphorylation, SUMOylation, and ubiquitination. Targeted PTM modulation, particularly in key proteins like Parkin, DJ1, and PINK1, emerges as a promising therapeutic strategy for mitigating dopaminergic degeneration in PD. Dysregulated PTMs significantly contribute to the accumulation of toxic protein aggregates and dopaminergic neuronal dysfunction observed in PD. Targeting PTMs, including epigenetic strategies, addressing aberrant phosphorylation events, and modulating SUMOylation processes, provides potential avenues for intervention. The ubiquitin-proteasome system, governed by enzymes like Parkin and Nedd4, offers potential targets for clearing misfolded proteins and developing disease-modifying interventions. Compounds like ginkgolic acid, SUMO E1 enzyme inhibitors, and natural compounds like Indole-3-carbinol illustrate the feasibility of modulating PTMs for therapeutic purposes in PD. This review underscores the therapeutic potential of PTM-targeted interventions in modulating PD-related pathways, emphasizing the need for further research in this promising area of Parkinsons disease therapeutics.

14-3-3 Family of Proteins: Biological Implications, Molecular Interactions, and Potential Intervention in Cancer, Virus and Neurodegeneration Disorders

The 14-3-3 family of proteins are highly conserved acidic eukaryotic proteins (25-32 kDa) abundantly present in the body. Through numerous binding partners, the 14-3-3 is responsible for many essential cellular pathways, such as cell cycle regulation and gene transcription control. Hence, its dysregulation has been linked to the onset of critical illnesses such as cancers, neurodegenerative diseases and viral infections. Interestingly, explorative studies have revealed an inverse correlation of 14-3-3 protein in cancer and neurodegenerative diseases, and the direct manipulation of 14-3-3 by virus to enhance infection capacity has dramatically extended its significance. Of these, COVID-19 has been linked to the 14-3-3 proteins by the interference of the SARS-CoV-2 nucleocapsid (N) protein during virion assembly. Given its predisposition towards multiple essential host signalling pathways, it is vital to understand the holistic interactions between the 14-3-3 protein to unravel its potential therapeutic unit in the future. As such, the general structure and properties of the 14-3-3 family of proteins, as well as their known biological functions and implications in cancer, neurodegeneration, and viruses, were covered in this review. Furthermore, the potential therapeutic target of 14-3-3 proteins in the associated diseases was discussed.

Multifaceted Roles of AFG3L2, a Mitochondrial ATPase in Relation to Neurological Disorders

AFG3L2 is a zinc metalloprotease and an ATPase localized in an inner mitochondrial membrane involved in mitochondrial quality control of several nuclear- and mitochondrial-encoded proteins. Mutations in AFG3L2 lead to diseases like slow progressive ataxia, which is a neurological disorder. This review delineates the cellular functions of AFG3L2 and its dysfunction that leads to major clinical outcomes, which include spinocerebellar ataxia type 28, spastic ataxia type 5, and optic atrophy type 12. It summarizes all relevant AFG3L2 mutations associated with the clinical outcomes to understand the detailed mechanisms attributable to its structure-related multifaceted roles in proteostasis and quality control. We face early diagnostic challenges of ataxia and optic neuropathy due to asymptomatic parents and variable clinical manifestations due to heterozygosity/homozygosity of AFG3L2 mutations. This review intends to promote AFG3L2 as a putative prognostic or diagnostic marker.

Unveiling the regulatory of miR-101-3p on ZNF746 in a Parkinson's disease cell model: Implications for therapeutic targeting

In this study, we explored the regulatory role of microRNA miR-101-3p on the zinc finger protein 746 (ZNF746), also known as PARIS, which is implicated in both sporadic and familial forms of Parkinson's disease. In a Parkinson's disease cell model, utilizing SH-SY5Y cells treated with 1-methyl-4-phenylpyridine (MPP+), we observed that miR-101-3p was downregulated, while ZNF746 was upregulated. To investigate the direct impact of miR-101-3p on ZNF746, our team conducted overexpression experiments, successfully reversing ZNF746's expression at both the mRNA and protein levels, as confirmed through quantitative PCR and western blotting. We also performed luciferase assays, providing compelling evidence that ZNF746 is a direct target of miR-101-3p. Additionally, we noted that miR-101-3p overexpression resulted in increased expression of PGC1α, a gene targeted by ZNF746. Functionally, we assessed the implications of miR-101-3p overexpression through MTS assays and flow cytometry, revealing significant promotion of cell viability, inhibition of ROS production, and reduced apoptosis in the Parkinson's disease cell model. In conclusion, this study highlights the role of miR-101-3p in regulating ZNF746 expression and suggests its potential as a therapeutic target for Parkinson's disease. These findings provide valuable molecular insights that could pave the way for innovative treatment strategies in combating this debilitating neurodegenerative disorder.

A neoteric annotation on the advances in combination therapy for Parkinson's disease: nanocarrier-based combination approach and future anticipation. Part I: exploring theoretical insights and pharmacological advances

INTRODUCTION

Parkinson's disease (PD) is a neurological condition defined by a substantial reduction in dopamine-containing cells in the substantia nigra. Levodopa (L-Dopa) is considered the gold standard in treatment. Recent research has clearly shown that resistance to existing therapies can develop. Moreover, the involvement of multiple pathways in the nigrostriatal dopaminergic neuronal loss suggests that modifying the treatment strategy could effectively reduce this degeneration.

AREAS COVERED

This review summarizes the key concerns with treating PD patients and the combinations, aimed at effectively managing PD. Part I focuses on the clinical diagnosis at every stage of the disease as well as the pharmacological treatment strategies that are applied throughout its course. It methodically elucidates the potency of multifactorial interventions in attenuating the disease trajectory, substantiating the rationale for co-administration of dual or multiple therapeutic agents. Significant emphasis is laid on evidence-based pharmacological combinations for PD management.

EXPERT OPINION

By utilizing multiple drugs in a combination fashion, this approach can leverage the additive or synergistic effects of these agents, amplify the spectrum of treatment, and curtail the risk of side effects by reducing the dose of each drug, demonstrating significantly greater efficacy.

USP30 inhibition induces mitophagy and reduces oxidative stress in parkin-deficient human neurons

Ubiquitination of mitochondrial proteins plays an important role in the cellular regulation of mitophagy. The E3 ubiquitin ligase parkin (encoded by PARK2) and the ubiquitin-specific protease 30 (USP30) have both been reported to regulate the ubiquitination of outer mitochondrial proteins and thereby mitophagy. Loss of E3 ligase activity is thought to be pathogenic in both sporadic and inherited Parkinson's disease (PD), with loss-of-function mutations in PARK2 being the most frequent cause of autosomal recessive PD. The aim of the present study was to evaluate whether mitophagy induced by USP30 inhibition provides a functional rescue in isogenic human induced pluripotent stem cell-derived dopaminergic neurons with and without PARK2 knockout (KO). Our data show that healthy neurons responded to CCCP-induced mitochondrial damage by clearing the impaired mitochondria and that this process was accelerated by USP30 inhibition. Parkin-deficient neurons showed an impaired mitophagic response to the CCCP challenge, although mitochondrial ubiquitination was enhanced. USP30 inhibition promoted mitophagy in PARK2 KO neurons, independently of whether left in basal conditions or treated with CCCP. In PARK2 KO, as in control neurons, USP30 inhibition balanced oxidative stress levels by reducing excessive production of reactive oxygen species. Interestingly, non-dopaminergic neurons were the main driver of the beneficial effects of USP30 inhibition. Our findings demonstrate that USP30 inhibition is a promising approach to boost mitophagy and improve cellular health, also in parkin-deficient cells, and support the potential relevance of USP30 inhibitors as a novel therapeutic approach in diseases with a need to combat neuronal stress mediated by impaired mitochondria.

Glutamate Receptors and C-ABL Inhibitors: A New Therapeutic Approach for Parkinson's Disease

Parkinson's disease (PD) is the second-most prevalent central nervous system (CNS) neurodegenerative condition. Over the past few decades, suppression of BCR-Abelson tyrosine kinase (c-Abl), which serves as a marker of -synuclein aggregation and oxidative stress, has shown promise as a potential therapy target in PD. c-Abl inhibition has the potential to provide neuroprotection against PD, as shown by experimental results and the first-in-human trial, which supports the strategy in bigger clinical trials. Furthermore, glutamate receptors have also been proposed as potential therapeutic targets for the treatment of PD since they facilitate and regulate synaptic neurotransmission throughout the basal ganglia motor system. It has been noticed that pharmacological manipulation of the receptors can change normal as well as abnormal neurotransmission in the Parkinsonian brain. The review study contributes to a comprehensive understanding of the approach toward the role of c-Abl and glutamate receptors in Parkinson's disease by highlighting the significance and urgent necessity to investigate new pharmacotherapeutic targets. The article covers an extensive insight into the concept of targeting, pathophysiology, and c-Abl interaction with α-synuclein, parkin, and cyclin-dependent kinase 5 (Cdk5). Furthermore, the concepts of Nmethyl- D-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPA) receptor, and glutamate receptors are discussed briefly. Conclusion: This review article focuses on in-depth literature findings supported by an evidence-based discussion on pre-clinical trials and clinical trials related to c-Abl and glutamate receptors that act as potential therapeutic targets for PD.

A Systematic Review of Various In-vivo Screening Models as well as the Mechanisms Involved in Parkinson's Disease Screening Procedures

BACKGROUND

Parkinson's disease is the second most common neurological ailment. It is also known that it affects practically all other brain components, although only gradually. Animal models are mostly used to test the efficacy of treatment against a specific enzyme and aid in creating a new drug dose.

OBJECTIVE

The purpose of this review is to highlight in vivo Parkinson's disease screening approaches, as well as the mechanism of action of each drug involved in Parkinson's disease development, and discuss the limitations of each model. In addition, it also sheds light on Parkinson's disease genetic models.

METHODS

The data for the publication was gathered from databases, such as PubMed, Bentham Science, Elsevier, Springer Nature, Wiley, and Research Gate, after a thorough examination of diverse research findings linked to Parkinson's disease and its screening models.

RESULTS

Each chemical or drug has a unique mechanism for causing disease, whether through the production of reactive oxygen species or the blockage of the dopamine receptor. Almost every disease symptom, whether physical or behavioral, is covered by each of the constructed models' unique set of indicators and symptoms.

CONCLUSION

Animal models are typically used to assess a medicine's activity against a specific enzyme and aid in the creation of a new drug dose. The process, restrictions, and mechanisms interfering with the screening, as well as the level of animal suffering, must all be thoroughly reviewed before any model for screening for Parkinson's disease can be implemented.

Toolkit for cellular studies of mammalian mitochondrial inorganic polyphosphate

Introduction: Inorganic polyphosphate (polyP) is an ancient polymer which is extremely well-conserved throughout evolution, and found in every studied organism. PolyP is composed of orthophosphates linked together by high-energy bonds, similar to those found in ATP. The metabolism and the functions of polyP in prokaryotes and simple eukaryotes are well understood. However, little is known about its physiological roles in mammalian cells, mostly due to its unknown metabolism and lack of systematic methods and effective models for the study of polyP in these organisms. Methods: Here, we present a comprehensive set of genetically modified cellular models to study mammalian polyP. Specifically, we focus our studies on mitochondrial polyP, as previous studies have shown the potent regulatory role of mammalian polyP in the organelle, including bioenergetics, via mechanisms that are not yet fully understood. Results: Using SH-SY5Y cells, our results show that the enzymatic depletion of mitochondrial polyP affects the expression of genes involved in the maintenance of mitochondrial physiology, as well as the structure of the organelle. Furthermore, this depletion has deleterious effects on mitochondrial respiration, an effect that is dependent on the length of polyP. Our results also show that the depletion of mammalian polyP in other subcellular locations induces significant changes in gene expression and bioenergetics; as well as that SH-SY5Y cells are not viable when the amount and/or the length of polyP are increased in mitochondria. Discussion: Our findings expand on the crucial role of polyP in mammalian mitochondrial physiology and place our cell lines as a valid model to increase our knowledge of both mammalian polyP and mitochondrial physiology.

Unraveling the Cave: A Seventy-Year Journey into the Caveolar Network, Cellular Signaling, and Human Disease

In the mid-1950s, a groundbreaking discovery revealed the fascinating presence of caveolae, referred to as flask-shaped invaginations of the plasma membrane, sparking renewed excitement in the field of cell biology. Caveolae are small, flask-shaped invaginations in the cell membrane that play crucial roles in diverse cellular processes, including endocytosis, lipid homeostasis, and signal transduction. The structural stability and functionality of these specialized membrane microdomains are attributed to the coordinated activity of scaffolding proteins, including caveolins and cavins. While caveolae and caveolins have been long appreciated for their integral roles in cellular physiology, the accumulating scientific evidence throughout the years reaffirms their association with a broad spectrum of human disorders. This review article aims to offer a thorough account of the historical advancements in caveolae research, spanning from their initial discovery to the recognition of caveolin family proteins and their intricate contributions to cellular functions. Furthermore, it will examine the consequences of a dysfunctional caveolar network in the development of human diseases.

Interactions of amyloidogenic proteins with mitochondrial protein import machinery in aging-related neurodegenerative diseases

Most mitochondrial proteins are targeted to the organelle by N-terminal mitochondrial targeting sequences (MTSs, or "presequences") that are recognized by the import machinery and subsequently cleaved to yield the mature protein. MTSs do not have conserved amino acid compositions, but share common physicochemical properties, including the ability to form amphipathic α-helical structures enriched with basic and hydrophobic residues on alternating faces. The lack of strict sequence conservation implies that some polypeptides can be mistargeted to mitochondria, especially under cellular stress. The pathogenic accumulation of proteins within mitochondria is implicated in many aging-related neurodegenerative diseases, including Alzheimer's, Parkinson's, and Huntington's diseases. Mechanistically, these diseases may originate in part from mitochondrial interactions with amyloid-β precursor protein (APP) or its cleavage product amyloid-β (Aβ), α-synuclein (α-syn), and mutant forms of huntingtin (mHtt), respectively, that are mediated in part through their associations with the mitochondrial protein import machinery. Emerging evidence suggests that these amyloidogenic proteins may present cryptic targeting signals that act as MTS mimetics and can be recognized by mitochondrial import receptors and transported into different mitochondrial compartments. Accumulation of these mistargeted proteins could overwhelm the import machinery and its associated quality control mechanisms, thereby contributing to neurological disease progression. Alternatively, the uptake of amyloidogenic proteins into mitochondria may be part of a protein quality control mechanism for clearance of cytotoxic proteins. Here we review the pathomechanisms of these diseases as they relate to mitochondrial protein import and effects on mitochondrial function, what features of APP/Aβ, α-syn and mHtt make them suitable substrates for the import machinery, and how this information can be leveraged for the development of therapeutic interventions.

Pain in monogenic Parkinson's disease: a comprehensive review

Pain, a challenging symptom experienced by individuals diagnosed with Parkinson's disease (PD), still lacks a comprehensive understanding of its underlying pathophysiological mechanisms. A systematic investigation of its prevalence and impact on the quality of life in patients affected by monogenic forms of PD has yet to be undertaken. This comprehensive review aims to provide an overview of the association between pain and monogenic forms of PD, specifically focusing on pathogenic variants in SNCA, PRKN, PINK1, PARK7, LRRK2, GBA1, VPS35, ATP13A2, DNAJC6, FBXO7, and SYNJ1. Sixty-three articles discussing pain associated with monogenic PD were identified and analyzed. The included studies exhibited significant heterogeneity in design, sample size, and pain outcome measures. Nonetheless, the findings of this review suggest that patients with monogenic PD may experience specific types of pain depending on the pathogenic variant present, distinguishing them from non-carriers. For instance, individuals with SNCA pathogenic variants have reported painful dystonia, lower extremity pain, dorsal pain, and upper back pain. However, these observations are primarily based on case reports with unclear prevalence. Painful lower limb dystonia and lower back pain are prominent symptoms in PRKN carriers. A continual correlation has been noted between LRRK2 mutations and the emergence of pain, though the conflicting research outcomes pose challenges in reaching definitive conclusions. Individuals with PINK1 mutation carriers also frequently report experiencing pain. Pain has been frequently reported as an initial symptom and the most troublesome one in GBA1-PD patients compared to those with idiopathic PD. The evidence regarding pain in ATP13A2, PARK7, VPS35, DNAJC6, FBXO7, and SYNJ1pathogenic variants is limited and insufficient. The potential linkage between genetic profiles and pain outcomes holds promising clinical implications, allowing for the potential stratification of patients in clinical trials and the development of personalized treatments for pain in monogenic PD. In conclusion, this review underscores the need for further research to unravel the intricate relationship between pain and monogenic forms of PD. Standardized methodologies, larger sample sizes, and longitudinal studies are essential to elucidate the underlying mechanisms and develop targeted therapeutic interventions for pain management in individuals with monogenic PD.

Senolytic and senomorphic secondary metabolites as therapeutic agents in Drosophila melanogaster models of Parkinson's disease

Drosophila melanogaster is a valuable model organism for a wide range of biological exploration. The well-known advantages of D. melanogaster include its relatively simple biology, the ease with which it is genetically modified, the relatively low financial and time costs associated with their short gestation and life cycles, and the large number of offspring they produce per generation. D. melanogaster has facilitated the discovery of many significant insights into the pathology of Parkinson's disease (PD) and has served as an excellent preclinical model of PD-related therapeutic discovery. In this review, we provide an overview of the major D. melanogaster models of PD, each of which provide unique insights into PD-relevant pathology and therapeutic targets. These models are discussed in the context of their past, current, and future potential use for studying the utility of secondary metabolites as therapeutic agents in PD. Over the last decade, senolytics have garnered an exponential interest in their ability to mitigate a broad spectrum of diseases, including PD. Therefore, an emphasis is placed on the senolytic and senomorphic properties of secondary metabolites. It is expected that D. melanogaster will continue to be critical in the effort to understand and improve treatment of PD, including their involvement in translational studies focused on secondary metabolites.

The Involvement of Neuroinflammation in the Onset and Progression of Parkinson's Disease

Parkinson's disease is a neurodegenerative disease exhibiting the fastest growth in incidence in recent years. As with most neurodegenerative diseases, the pathophysiology is incompletely elucidated, but compelling evidence implicates inflammation, both in the central nervous system and in the periphery, in the initiation and progression of the disease, although it is not yet clear what triggers this inflammatory response and where it begins. Gut dysbiosis seems to be a likely candidate for the initiation of the systemic inflammation. The therapies in current use provide only symptomatic relief, but do not interfere with the disease progression. Nonetheless, animal models have shown promising results with therapies that target various vicious neuroinflammatory cascades. Translating these therapeutic strategies into clinical trials is still in its infancy, and a series of issues, such as the exact timing, identifying biomarkers able to identify Parkinson's disease in early and pre-symptomatic stages, or the proper indications of genetic testing in the population at large, will need to be settled in future guidelines.

Role of dopamine in the pathophysiology of Parkinson's disease

A pathological feature of Parkinson's disease (PD) is the progressive loss of dopaminergic neurons and decreased dopamine (DA) content in the substantia nigra pars compacta in PD brains. DA is the neurotransmitter of dopaminergic neurons. Accumulating evidence suggests that DA interacts with environmental and genetic factors to contribute to PD pathophysiology. Disturbances of DA synthesis, storage, transportation and metabolism have been shown to promote neurodegeneration of dopaminergic neurons in various PD models. DA is unstable and can undergo oxidation and metabolism to produce multiple reactive and toxic by-products, including reactive oxygen species, DA quinones, and 3,4-dihydroxyphenylacetaldehyde. Here we summarize and highlight recent discoveries on DA-linked pathophysiologic pathways, and discuss the potential protective and therapeutic strategies to mitigate the complications associated with DA.

Parkinson's Neuropathology Puzzle: A Systematic Review Uncovering the Pathological Culprits Behind the Neurological Disease

Being one of the most prevalent progressive neurodegenerative disorders (falling second only to Alzheimer's disease) with a clinical pattern affecting millions of lives all over the world, Parkinson's disease (PD) has never failed to attract a formidable interest from the vast majority of neurologists and researchers worldwide. This review article will analyze the pathophysiology, etiology, genetics, and pathological stages of Parkinson's disease with their corresponding clinical sequels. A review article was conducted using research databases including PubMed, PubMed Central, Springer, and Elsevier. The research articles reviewed using databases were written in English, German, Japanese, and Chinese and published within the preceding 50 years. Based on the article's findings, we concluded that Parkinson's disease is a progressive disorder with a variety of motor and non-motor symptoms that are influenced by a cascade of pathological neuronal abnormalities such as Lewy neurites and Lewy bodies that gradually build up with an eventual consequence of neurodegeneration of dopamine-secreting neurons. Multiple genetic mutations, pathophysiological events, and environmental factors act as the foundation to initiate that cascade.

Targeting the Cysteine Redox Proteome in Parkinson's Disease: The Role of Glutathione Precursors and Beyond

Encouraging recent data on the molecular pathways underlying aging have identified variants and expansions of genes associated with DNA replication and repair, telomere and stem cell maintenance, regulation of the redox microenvironment, and intercellular communication. In addition, cell rejuvenation requires silencing some transcription factors and the activation of pluripotency, indicating that hidden molecular networks must integrate and synchronize all these cellular mechanisms. Therefore, in addition to gene sequence expansions and variations associated with senescence, the optimization of transcriptional regulation and protein crosstalk is essential. The protein cysteinome is crucial in cellular regulation and plays unexpected roles in the aging of complex organisms, which show cumulative somatic mutations, telomere attrition, epigenetic modifications, and oxidative dysregulation, culminating in cellular senescence. The cysteine thiol groups are highly redox-active, allowing high functional versatility as structural disulfides, redox-active disulfides, active-site nucleophiles, proton donors, and metal ligands to participate in multiple regulatory sites in proteins. Also, antioxidant systems control diverse cellular functions, including the transcription machinery, which partially depends on the catalytically active cysteines that can reduce disulfide bonds in numerous target proteins, driving their biological integration. Since we have previously proposed a fundamental role of cysteine-mediated redox deregulation in neurodegeneration, we suggest that cellular rejuvenation of the cysteine redox proteome using GSH precursors, like N-acetyl-cysteine, is an underestimated multitarget therapeutic approach that would be particularly beneficial in Parkinson's disease.

Translating Pathological Brain Activity Primers in Parkinson's Disease Research

Translational experimental approaches that help us better trace Parkinson's disease (PD) pathophysiological mechanisms leading to new therapeutic targets are urgently needed. In this article, we review recent experimental and clinical studies addressing abnormal neuronal activity and pathological network oscillations, as well as their underlying mechanisms and modulation. Our aim is to enhance our knowledge about the progression of Parkinson's disease pathology and the timing of its symptom's manifestation. Here, we present mechanistic insights relevant for the generation of aberrant oscillatory activity within the cortico-basal ganglia circuits. We summarize recent achievements extrapolated from available PD animal models, discuss their advantages and limitations, debate on their differential applicability, and suggest approaches for transferring knowledge on disease pathology into future research and clinical applications.

Glymphatic System and Mitochondrial Dysfunction as Two Crucial Players in Pathophysiology of Neurodegenerative Disorders

Neurodegenerative diseases are a complex problem affecting millions of people around the world. The pathogenesis is not fully understood, but it is known that both insufficiency of the glymphatic system and mitochondrial disorders affect the development of pathology. It appears that these are not just two independent factors that coexist in the processes of neurodegeneration, but that they often interact and drive each other. Bioenergetics disturbances are potentially associated with the accumulation of protein aggregates and impaired glymphatic clearance. Furthermore, sleep disorders characteristic of neurodegeneration may impair the work of both the glymphatic system and the activity of mitochondria. Melatonin may be one of the elements linking sleep disorders with the function of these systems. Moreover, noteworthy in this context is the process of neuroinflammation inextricably linked to mitochondria and its impact not only on neurons, but also on glia cells involved in glymphatic clearance. This review only presents possible direct and indirect connections between the glymphatic system and mitochondria in the process of neurodegeneration. Clarifying the connection between these two areas in relation to neurodegeneration could lead to the development of new multidirectional therapies, which, due to the complexity of pathogenesis, seems to be worth considering.

Resveratrol in Neurodegeneration, in Neurodegenerative Diseases, and in the Redox Biology of the Mitochondria

Neurodegeneration is a process leading to the progressive loss of structure and functions of neurons. Many neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and Huntington's disease have shown many common points at the subcellular level. Neurons are metabolically active cells and need a high amount of energy. Mitochondria are known as the energy synthesis center for cells, involved in the synthesis of adenosine triphosphate by oxidative phosphorylation. Rather than just being an energy synthesis center, it has critical importance for many cellular functions such as calcium homeostasis, cell proliferation, cell growth, and apoptosis. In the process of mitochondrial dysfunction, cellular functions are disrupted and cells enter the apoptotic or necrotic pathway. Resveratrol (trans-3,5,4-trihydoxystilbene), a plant-derived polyphenol found in the seed of grapes, berries, peanuts, and wine, has many biological effects such as inhibition of lipid peroxidation, scavenging of free radicals, changes in eicosanoid synthesis, inhibition of platelet aggregation, anti-inflammatory and anticancer activity, and regulation of lipid metabolism. Through the reviewed literature, the current study investigated the protective role of resveratrol in neurodegenerative diseases. Studies show that resveratrol moderates mitochondrial function, redox status, and cellular dynamics in both in vivo and in vitro experimental models of neurodegeneration. Resveratrol suppresses reactive oxygen species production by reducing the activity of complex III due to its competition effect with coenzyme Q. In the present work, we discussed the protective effects of resveratrol on neurodegeneration, neurodegenerative diseases, and the redox biology of the mitochondria.

Protein stabilization of ITF2 by NF-κB prevents colitis-associated cancer development

Chronic colonic inflammation is a feature of cancer and is strongly associated with tumorigenesis, but its underlying molecular mechanisms remain poorly understood. Inflammatory conditions increased ITF2 and p65 expression both ex vivo and in vivo, and ITF2 and p65 showed positive correlations. p65 overexpression stabilized ITF2 protein levels by interfering with the binding of Parkin to ITF2. More specifically, the C-terminus of p65 binds to the N-terminus of ITF2 and inhibits ubiquitination, thereby promoting ITF2 stabilization. Parkin acts as a E3 ubiquitin ligase for ITF2 ubiquitination. Intestinal epithelial-specific deletion of ITF2 facilitated nuclear translocation of p65 and thus increased colitis-associated cancer tumorigenesis, which was mediated by Azoxymethane/Dextran sulfate sodium or dextran sulfate sodium. Upregulated ITF2 expression was lost in carcinoma tissues of colitis-associated cancer patients, whereas p65 expression much more increased in both dysplastic and carcinoma regions. Therefore, these findings indicate a critical role for ITF2 in the repression of colitis-associated cancer progression and ITF2 would be an attractive target against inflammatory diseases including colitis-associated cancer.

Senolytics: opening avenues in drug discovery to find novel therapeutics for Parkinson's disease

Aging is one of the major risk factors for most neurodegenerative disorders including Parkinson's disease (PD). More than 10 million people are affected with PD worldwide. One of the predominant factors accountable for progression of PD pathology could be enhanced accumulation of senescent cells in the brain with the progress of age. Recent investigations have highlighted that senescent cells can ignite PD pathology via increased oxidative stress and neuroinflammation. Senolytics are agents that kill senescent cells. This review mainly focuses on understanding the pathological connection between senescence and PD, with emphasis on some of the recent advances made in the area of senolytics and their evolution to potential clinical candidates for future pharmaceuticals against PD.

Unwinding the modalities of necrosome activation and necroptosis machinery in neurological diseases

Necroptosis, a regulated form of cell death, is involved in the genesis and development of various life-threatening diseases, including cancer, neurological disorders, cardiac myopathy, and diabetes. Necroptosis initiates with the formation and activation of a necrosome complex, which consists of RIPK1, RIPK2, RIPK3, and MLKL. Emerging studies has demonstrated the regulation of the necroptosis cell death pathway through the implication of numerous post-translational modifications, namely ubiquitination, acetylation, methylation, SUMOylation, hydroxylation, and others. In addition, the negative regulation of the necroptosis pathway has been shown to interfere with brain homeostasis through the regulation of axonal degeneration, mitochondrial dynamics, lysosomal defects, and inflammatory response. Necroptosis is controlled by the activity and expression of signaling molecules, namely VEGF/VEGFR, PI3K/Akt/GSK-3β, c-Jun N-terminal kinases (JNK), ERK/MAPK, and Wnt/β-catenin. Herein, we briefly discussed the implication and potential of necrosome activation in the pathogenesis and progression of neurological manifestations, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, traumatic brain injury, and others. Further, we present a detailed picture of natural compounds, micro-RNAs, and chemical compounds as therapeutic agents for treating neurological manifestations.

Redox Modulation of Mitochondrial Proteins in the Neurotoxicant Models of Parkinson's Disease

Significance: Mitochondrial proteins regulate the oxidative phosphorylation, cellular metabolism, and free radical generation. Redox modulation alters the mitochondrial proteins and instigates the damage to dopaminergic neurons. Toxicants contribute to Parkinson's disease (PD) pathogenesis in conjunction with aging and genetic factors. While oxidative modulation of a number of mitochondrial proteins is linked to xenobiotic exposure, little is known about its role in the toxicant-induced PD. Understanding the role of redox modulation of mitochondrial proteins in complex cellular events leading to neurodegeneration is highly relevant. Recent Advances: Many toxicants are shown to inhibit complex I or III and elicit free radical production that alters the redox status of mitochondrial proteins. Implication of redox modulation of the mitochondrial proteins makes them a target to comprehend the underlying mechanism of toxicant-induced PD. Critical Issues: Owing to multifactorial etiology, exploration of onset and progression and treatment outcomes needs a comprehensive approach. The article explains about a few mitochondrial proteins that undergo redox changes along with the promising strategies, which help to alleviate the toxicant-induced redox imbalance leading to neurodegeneration. Future Directions: Although mitochondrial proteins are linked to PD, their role in toxicant-induced parkinsonism is not yet completely known. Preservation of antioxidant defense machinery could alleviate the redox modulation of mitochondrial proteins. Targeted antioxidant delivery, use of metal chelators, and activation of nuclear factor erythroid 2-related factor 2, and combinational therapy that encounters multiple free radicals, could ameliorate the redox modulation of mitochondrial proteins and thereby PD progression.

E3 Ligases Meet Their Match: Fragment-Based Approaches to Discover New E3 Ligands and to Unravel E3 Biology

Ubiquitination is a key post-translational modification of proteins, affecting the regulation of multiple cellular processes. Cells are equipped with over 600 ubiquitin orchestrators, called E3 ubiquitin ligases, responsible for directing the covalent attachment of ubiquitin to substrate proteins. Due to their regulatory role in cells, significant efforts have been made to discover ligands for E3 ligases. The recent emergence of the proteolysis targeting chimera (PROTAC) and molecular glue degrader (MGD) modalities has further increased interest in E3 ligases as drug targets. This perspective focuses on how fragment based lead discovery (FBLD) methods have been used to discover new ligands for this important target class. In some cases these efforts have led to clinical candidates; in others, they have provided tools for deepening our understanding of E3 ligase biology. Recently, FBLD-derived ligands have inspired the design of PROTACs that are able to artificially modulate protein levels in cells.

Genome-wide association study of brain biochemical phenotypes reveals distinct genetic architecture of Alzheimer's disease related proteins

BACKGROUND

Alzheimer's disease (AD) is neuropathologically characterized by amyloid-beta (Aβ) plaques and neurofibrillary tangles. The main protein components of these hallmarks include Aβ40, Aβ42, tau, phosphor-tau, and APOE. We hypothesize that genetic variants influence the levels and solubility of these AD-related proteins in the brain; identifying these may provide key insights into disease pathogenesis.

METHODS

Genome-wide genotypes were collected from 441 AD cases, imputed to the haplotype reference consortium (HRC) panel, and filtered for quality and frequency. Temporal cortex levels of five AD-related proteins from three fractions, buffer-soluble (TBS), detergent-soluble (Triton-X = TX), and insoluble (Formic acid = FA), were available for these same individuals. Variants were tested for association with each quantitative biochemical measure using linear regression, and GSA-SNP2 was used to identify enriched Gene Ontology (GO) terms. Implicated variants and genes were further assessed for association with other relevant variables.

RESULTS

We identified genome-wide significant associations at seven novel loci and the APOE locus. Genes and variants at these loci also associate with multiple AD-related measures, regulate gene expression, have cell-type specific enrichment, and roles in brain health and other neuropsychiatric diseases. Pathway analysis identified significant enrichment of shared and distinct biological pathways.

CONCLUSIONS

Although all biochemical measures tested reflect proteins core to AD pathology, our results strongly suggest that each have unique genetic architecture and biological pathways that influence their specific biochemical states in the brain. Our novel approach of deep brain biochemical endophenotype GWAS has implications for pathophysiology of proteostasis in AD that can guide therapeutic discovery efforts focused on these proteins.

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.

Pathological and Therapeutic Advances in Parkinson's Disease: Mitochondria in the Interplay

Parkinson's disease (PD) is the second most common neurodegenerative illness majorly affecting the population between the ages of 55 to 65 years. Progressive dopaminergic neuronal loss and the collective assemblage of misfolded alpha-synuclein in the substantia nigra, remain notable neuro-pathological hallmarks of the disease. Multitudes of mechanistic pathways have been proposed in attempts to unravel the pathogenesis of PD but still, it remains elusive. The convergence of PD pathology is found in organelle dysfunction where mitochondria remain a major contributor. Mitochondrial processes like bioenergetics, mitochondrial dynamics, and mitophagy are under strict regulation by the mitochondrial genome and nuclear genome. These processes aggravate neurodegenerative activities upon alteration through neuroinflammation, oxidative damage, apoptosis, and proteostatic stress. Therefore, the mitochondria have grabbed a central position in the patho-mechanistic exploration of neurodegenerative diseases like PD. The management of PD remains a challenge to physicians to date, due to the variable therapeutic response of patients and the limitation of conventional chemical agents which only offer symptomatic relief with minimal to no disease-modifying effect. This review describes the patho-mechanistic pathways involved in PD not only limited to protein dyshomeostasis and oxidative stress, but explicit attention has been drawn to exploring mechanisms like organelle dysfunction, primarily mitochondria and mitochondrial genome influence, while delineating the newer exploratory targets such as GBA1, GLP, LRRK2, and miRNAs and therapeutic agents targeting them.

Unraveling Parkinson's Disease Neurodegeneration: Does Aging Hold the Clues?

Aging is the greatest risk factor for Parkinson's disease (PD), suggesting that mechanisms driving the aging process promote PD neurodegeneration. Several lines of evidence support a role for aging in PD. First, hallmarks of brain aging such as mitochondrial dysfunction and oxidative stress, loss of protein homeostasis, and neuroinflammation are centrally implicated in PD development. Second, mutations that cause monogenic PD are present from conception, yet typically only cause disease following a period of aging. Third, lifespan-extending genetic, dietary, or pharmacological interventions frequently attenuate PD-related neurodegeneration. These observations support a central role for aging in disease development and suggest that new discoveries in the biology of aging could be leveraged to elucidate novel mechanisms of PD pathophysiology. A recent rapid growth in our understanding of conserved molecular pathways that govern model organism lifespan and healthspan has highlighted a key role for metabolism and nutrient sensing pathways. Uncovering how metabolic pathways involving NAD+ consumption, insulin, and mTOR signaling link to the development of PD is underway and implicates metabolism in disease etiology. Here, we assess areas of convergence between nervous system aging and PD, evaluate the link between metabolism, aging, and PD and address the potential of metabolic interventions to slow or halt the onset of PD-related neurodegeneration drawing on evidence from cellular and animal models.

Role of SUMOylation in Neurodegenerative Diseases

Neurodegenerative diseases (NDDs) are irreversible, progressive diseases with no effective treatment. The hallmark of NDDs is the aggregation of misfolded, modified proteins, which impair neuronal vulnerability and cause brain damage. The loss of synaptic connection and the progressive loss of neurons result in cognitive defects. Several dysregulated proteins and overlapping molecular mechanisms contribute to the pathophysiology of NDDs. Post-translational modifications (PTMs) are essential regulators of protein function, trafficking, and maintaining neuronal hemostasis. The conjugation of a small ubiquitin-like modifier (SUMO) is a reversible, dynamic PTM required for synaptic and cognitive function. The onset and progression of neurodegenerative diseases are associated with aberrant SUMOylation. In this review, we have summarized the role of SUMOylation in regulating critical proteins involved in the onset and progression of several NDDs.

Reactive sulfur species and their significance in health and disease

Reactive sulfur species (RSS) have been recognized in the last two decades as very important molecules in redox regulation. They are involved in metabolic processes and, in this way, they are responsible for maintenance of health. This review summarizes current information about the essential biological RSS, including H₂S, low molecular weight persulfides, protein persulfides as well as organic and inorganic polysulfides, their synthesis, catabolism and chemical reactivity. Moreover, the role of RSS disturbances in various pathologies including vascular diseases, chronic kidney diseases, diabetes mellitus Type 2, neurological diseases, obesity, chronic obstructive pulmonary disease and in the most current problem of COVID-19 is presented. The significance of RSS in aging is also mentioned. Finally, the possibilities of using the precursors of various forms of RSS for therapeutic purposes are discussed.

The use of fibroblasts as a valuable strategy for studying mitochondrial impairment in neurological disorders

Neurological disorders (NDs) are characterized by progressive neuronal dysfunction leading to synaptic failure, cognitive impairment, and motor injury. Among these diseases, Alzheimer's disease (AD), Parkinson's disease (PD), Huntington’s disease (HD), and amyotrophic lateral sclerosis (ALS) have raised a significant research interest. These disorders present common neuropathological signs, including neuronal dysfunction, protein accumulation, oxidative damage, and mitochondrial abnormalities. In this context, mitochondrial impairment is characterized by a deficiency in ATP production, excessive production of reactive oxygen species, calcium dysregulation, mitochondrial transport failure, and mitochondrial dynamics deficiencies. These defects in mitochondrial health could compromise the synaptic process, leading to early cognitive dysfunction observed in these NDs. Interestingly, skin fibroblasts from AD, PD, HD, and ALS patients have been suggested as a useful strategy to investigate and detect early mitochondrial abnormalities in these NDs. In this context, fibroblasts are considered a viable model for studying neurodegenerative changes due to their metabolic and biochemical relationships with neurons. Also, studies of our group and others have shown impairment of mitochondrial bioenergetics in fibroblasts from patients diagnosed with sporadic and genetic forms of AD, PD, HD, and ALS. Interestingly, these mitochondrial abnormalities have been observed in the brain tissues of patients suffering from the same pathologies. Therefore, fibroblasts represent a novel strategy to study the genesis and progression of mitochondrial dysfunction in AD, PD, HD, and ALS. This review discusses recent evidence that proposes fibroblasts as a potential target to study mitochondrial bioenergetics impairment in neurological disorders and consequently to search for new biomarkers of neurodegeneration.

Astrocytes in Neurodegeneration: Inspiration From Genetics

Despite the discovery of numerous molecules and pathologies, the pathophysiology of various neurodegenerative diseases remains unknown. Genetics participates in the pathogenesis of neurodegeneration. Neural dysfunction, which is thought to be a cell-autonomous mechanism, is insufficient to explain the development of neurodegenerative disease, implying that other cells surrounding or related to neurons, such as glial cells, are involved in the pathogenesis. As the primary component of glial cells, astrocytes play a variety of roles in the maintenance of physiological functions in neurons and other glial cells. The pathophysiology of neurodegeneration is also influenced by reactive astrogliosis in response to central nervous system (CNS) injuries. Furthermore, those risk-gene variants identified in neurodegenerations are involved in astrocyte activation and senescence. In this review, we summarized the relationships between gene variants and astrocytes in four neurodegenerative diseases, including Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Parkinson’s disease (PD), and provided insights into the implications of astrocytes in the neurodegenerations.

Senescence: Pathogenic Driver in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is recognized as a disease of accelerated lung aging. Over the past two decades, mounting evidence suggests an accumulation of senescent cells within the lungs of patients with COPD that contributes to dysregulated tissue repair and the secretion of multiple inflammatory proteins, termed the senescence-associated secretory phenotype (SASP). Cellular senescence in COPD is linked to telomere dysfunction, DNA damage, and oxidative stress. This review gives an overview of the mechanistic contributions and pathologic consequences of cellular senescence in COPD and discusses potential therapeutic approaches targeting senescence-associated signaling in COPD.

Thermal stress induces expression of Nuclear protein and Parkin genes in endangered catfish, Clarias magur

Fluctuation in water temperature can create thermal stress, which may impact many aspects of fish life, such as survival, growth, reproduction, disease occurrence etc. The endangered catfish, Clarias magur, has been reported to survive at higher thermal stress, even though the exact mechanism is unknown. The genes coding for Nuclear protein 1 (Nupr1) and Parkin E3 ubiquitin protein ligase (Park2) have been reported to protect cells from stress-induced damage and death. In this study, we characterized both the genes and assessed their quantitative expression in C. magur. Structural features of both the genes were found similar to a related catfish, Ictalurus punctatus, and model fish zebrafish. The genes were fairly conserved in fishes as observed through phylogenetic analysis. The real time expression of the two stress-associated genes were also assessed in brain, kidney, liver and muscle tissues of C. magur exposed to warm (34 °C) and cold (15 °C) water. RT-PCR analysis revealed up-regulation in the relative expression levels of Nupr1 and Park2 genes at both temperatures with maximum positive fold change during stress to cold water, even though the posteriori Dunnett's test after ANOVA revealed that there were significant differences between the control and challenged groups. The study indicated that Nupr1 gene plays role in muscle tissue at both high and low thermal stress, but at high thermal stress in liver, while Park2 plays role in muscle, brain and kidney at low temperature and in liver at high temperature stress in C. magur. The study has generated first-hand information under warm- and cold water, which pave the way to understand the expression response of these genes to thermal vacillations and to establish evolutionary significance in catfishes and other species.

Ubiquitin and Ubiquitin-like Proteins in Cancer, Neurodegenerative Disorders, and Heart Diseases

Post-translational modification (PTM) is an essential mechanism for enhancing the functional diversity of proteins and adjusting their signaling networks. The reversible conjugation of ubiquitin (Ub) and ubiquitin-like proteins (Ubls) to cellular proteins is among the most prevalent PTM, which modulates various cellular and physiological processes by altering the activity, stability, localization, trafficking, or interaction networks of its target molecules. The Ub/Ubl modification is tightly regulated as a multi-step enzymatic process by enzymes specific to this family. There is growing evidence that the dysregulation of Ub/Ubl modifications is associated with various diseases, providing new targets for drug development. In this review, we summarize the recent progress in understanding the roles and therapeutic targets of the Ub and Ubl systems in the onset and progression of human diseases, including cancer, neurodegenerative disorders, and heart diseases.

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.

Ubiquitinomics: history, methods and applications in basic research and drug discovery

The ubiquitin-proteasome system (UPS) was discovered about 40 years ago and is known to regulate a multitude of cellular processes including protein homeostasis. ubiquitylated proteins are recognized by downstream effectors, resulting in alterations of protein abundance, activity, or localization. Not surprisingly, the ubiquitylation machinery is dysregulated in numerous diseases, including cancers and neurodegeneration. Mass spectrometry (MS)-based proteomics has emerged as a transformative technology for characterizing protein ubiquitylation in an unbiased fashion. Here, we provide an overview of the different MS-based approaches for studying protein ubiquitylation. We review various methods for enriching and quantifying ubiquitin modifications at the peptide or protein level, outline MS acquisition and data processing approaches and discuss key challenges. Finally, we examine how MS-based ubiquitinomics can aid both basic biology and drug discovery research. This article is protected by copyright. All rights reserved.

Transcriptional analysis of peripheral memory T cells reveals Parkinson's disease-specific gene signatures

Parkinson's disease (PD) is a multi-stage neurodegenerative disorder with largely unknown etiology. Recent findings have identified PD-associated autoimmune features including roles for T cells. To further characterize the role of T cells in PD, we performed RNA sequencing on PBMC and peripheral CD4 and CD8 memory T cell subsets derived from PD patients and age-matched healthy controls. When the groups were stratified by their T cell responsiveness to alpha-synuclein (α-syn) as a proxy for an ongoing inflammatory autoimmune response, the study revealed a broad differential gene expression profile in memory T cell subsets and a specific PD associated gene signature. We identified significant enrichment of transcriptomic signatures previously associated with PD, including for oxidative stress, phosphorylation, autophagy of mitochondria, cholesterol metabolism and inflammation, and the chemokine signaling proteins CX3CR1, CCR5, and CCR1. In addition, we identified genes in these peripheral cells that have previously been shown to be involved in PD pathogenesis and expressed in neurons, such as LRRK2, LAMP3, and aquaporin. Together, these findings suggest that features of circulating T cells with α-syn-specific responses in PD patients provide insights into the interactive processes that occur during PD pathogenesis and suggest potential intervention targets.

The Role of NEDD4 E3 Ubiquitin–Protein Ligases in Parkinson’s Disease

Parkinson’s disease (PD) is a debilitating neurodegenerative disease that causes a great clinical burden. However, its exact molecular pathologies are not fully understood. Whilst there are a number of avenues for research into slowing, halting, or reversing PD, one central idea is to enhance the clearance of the proposed aetiological protein, oligomeric α-synuclein. Oligomeric α-synuclein is the main constituent protein in Lewy bodies and neurites and is considered neurotoxic. Multiple E3 ubiquitin-protein ligases, including the NEDD4 (neural precursor cell expressed developmentally downregulated protein 4) family, parkin, SIAH (mammalian homologues of Drosophila seven in absentia), CHIP (carboxy-terminus of Hsc70 interacting protein), and SCFFXBL5 SCF ubiquitin ligase assembled by the S-phase kinase-associated protein (SKP1), cullin-1 (Cul1), a zinc-binding RING finger protein, and the F-box domain/Leucine-rich repeat protein 5-containing protein FBXL5), have been shown to be able to ubiquitinate α-synuclein, influencing its subsequent degradation via the proteasome or lysosome. Here, we explore the link between NEDD4 ligases and PD, which is not only via α-synuclein but further strengthened by several additional substrates and interaction partners. Some members of the NEDD4 family of ligases are thought to crosstalk even with PD-related genes and proteins found to be mutated in familial forms of PD. Mutations in NEDD4 family genes have not been observed in PD patients, most likely because of their essential survival function during development. Following further in vivo studies, it has been thought that NEDD4 ligases may be viable therapeutic targets in PD. NEDD4 family members could clear toxic proteins, enhancing cell survival and slowing disease progression, or might diminish beneficial proteins, reducing cell survival and accelerating disease progression. Here, we review studies to date on the expression and function of NEDD4 ubiquitin ligases in the brain and their possible impact on PD pathology.

An assessment of the rescue action of resveratrol in parkin loss of function-induced oxidative stress in Drosophila melanogaster

Loss-of-function mutations in parkin is associated with onset of juvenile Parkinson's disease (PD). Resveratrol is a polyphenolic stilbene with neuroprotective activity. Here, we evaluated the rescue action of resveratrol in parkin mutant D. melanogaster. The control flies (w1118) received diet-containing 2% ethanol (vehicle), while the PD flies received diets-containing resveratrol (15, 30 and 60 mg/kg diet) for 21 days to assess survival rate. Consequently, similar treatments were carried out for 10 days to evaluate locomotor activity, oxidative stress and antioxidant markers. We also determined mRNA levels of Superoxide dismutase 1 (Sod1, an antioxidant gene) and ple, which encodes tyrosine hydroxylase, the rate-limiting step in dopamine synthesis. Our data showed that resveratrol improved survival rate and climbing activity of PD flies compared to untreated PD flies. Additionally, resveratrol protected against decreased activities of acetylcholinesterase and catalase and levels of non-protein thiols and total thiols displayed by PD flies. Moreover, resveratrol mitigated against parkin mutant-induced accumulations of hydrogen peroxide, nitric oxide and malondialdehyde. Resveratrol attenuated downregulation of ple and Sod1 and reduction in mitochondrial fluorescence intensity displayed by PD flies. Overall, resveratrol alleviated oxidative stress and locomotor deficit associated with parkin loss-of-function mutation and therefore might be useful for the management of PD.

Cognition in prodromal Parkinson's disease

One characteristic of Parkinson's disease (PD) is a prodromal phase, lasting many years during which both pre-clinical motor and non-motor symptoms occur. Around one-fifth of patients with PD manifest mild cognitive impairment at time of clinical diagnosis. Thus, important challenges are to define the time of onset of cognitive dysfunction in the prodromal phase of PD, and to define its co-occurrence with other specific characteristics. Evidence for cognitive change in prodromal PD comes from various study designs, including both longitudinal and cross-sectional approaches with different target groups. These studies support the concept that changes in global cognitive function and alterations in executive functions occur, and that these changes may be present up to 6 years before clinical PD diagnosis. Notably, this evidence led to including global cognitive impairment as an independent prodromal marker in the recently updated research criteria of the Movement Disorder Society for prodromal PD. Knowledge in this field, however, is still at its beginning, and evidence is sparse about many aspects of this topic. Further longitudinal studies including standardized assessments of global and domain-specific cognitive functions are needed to gain further knowledge about the first appearance, the course, and the interaction of cognitive deficits with other non-motor symptoms in prodromal stage PD. Treatment approaches, including non-pharmacological interventions, in individuals with prodromal PD might help to prevent or delay cognitive dysfunction in early PD.

Mechanism and Disease Association With a Ubiquitin Conjugating E2 Enzyme: UBE2L3

Ubiquitin conjugating enzyme E2 is an important component of the post-translational protein ubiquitination pathway, which mediates the transfer of activated ubiquitin to substrate proteins. UBE2L3, also called UBcH7, is one of many E2 ubiquitin conjugating enzymes that participate in the ubiquitination of many substrate proteins and regulate many signaling pathways, such as the NF-κB, GSK3β/p65, and DSB repair pathways. Studies on UBE2L3 have found that it has an abnormal expression in many diseases, mainly immune diseases, tumors and Parkinson's disease. It can also promote the occurrence and development of these diseases. Resultantly, UBE2L3 may become an important target for some diseases. Herein, we review the structure of UBE2L3, and its mechanism in diseases, as well as diseases related to UBE2L3 and discuss the related challenges.

N-Acetyl-Cysteine: Modulating the Cysteine Redox Proteome in Neurodegenerative Diseases

In the last twenty years, significant progress in understanding the pathophysiology of age-associated neurodegenerative diseases has been made. However, the prevention and treatment of these diseases remain without clinically significant therapeutic advancement. While we still hope for some potential genetic therapeutic approaches, the current reality is far from substantial progress. With this state of the issue, emphasis should be placed on early diagnosis and prompt intervention in patients with increased risk of neurodegenerative diseases to slow down their progression, poor prognosis, and decreasing quality of life. Accordingly, it is urgent to implement interventions addressing the psychosocial and biochemical disturbances we know are central in managing the evolution of these disorders. Genomic and proteomic studies have shown the high molecular intricacy in neurodegenerative diseases, involving a broad spectrum of cellular pathways underlying disease progression. Recent investigations indicate that the dysregulation of the sensitive-cysteine proteome may be a concurrent pathogenic mechanism contributing to the pathophysiology of major neurodegenerative diseases, opening new therapeutic opportunities. Considering the incidence and prevalence of these disorders and their already significant burden in Western societies, they will become a real pandemic in the following decades. Therefore, we propose large-scale investigations, in selected groups of people over 40 years of age with decreased blood glutathione levels, comorbidities, and/or mild cognitive impairment, to evaluate supplementation of the diet with low doses of N-acetyl-cysteine, a promising and well-tolerated therapeutic agent suitable for long-term use.

Crosstalk Between the NLRP3 Inflammasome/ASC Speck and Amyloid Protein Aggregates Drives Disease Progression in Alzheimer's and Parkinson's Disease

Two key pathological hallmarks of neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD), are the accumulation of misfolded protein aggregates and the chronic progressive neuroinflammation that they trigger. Numerous original research and reviews have provided a comprehensive understanding of how aggregated proteins (amyloid β, pathological tau, and α-synuclein) contribute to the disease, including driving sterile inflammation, in part, through the aggregation of multi-protein inflammasome complexes and the ASC speck [composed of NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3), Apoptosis-associated speck-like protein containing a C-terminal caspase activation and recruitment domain (ASC), and inflammatory caspase-1] involved in innate immunity. Here, we provide a unique perspective on the crosstalk between the aggregation-prone proteins involved in AD/PD and the multi-protein inflammasome complex/ASC speck that fuels feed-forward exacerbation of each other, driving neurodegeneration. Failed turnover of protein aggregates (both AD/PD related aggregates and the ASC speck) by protein degradation pathways, prionoid propagation of inflammation by the ASC speck, cross-seeding of protein aggregation by the ASC speck, and pro-aggregatory cleavage of proteins by caspase-1 are some of the mechanisms that exacerbate disease progression. We also review studies that provide this causal framework and highlight how the ASC speck serves as a platform for the propagation and spreading of inflammation and protein aggregation that drives AD and PD.