Mitochondrial Dysfunction and Mitophagy in Parkinson's Disease: From Mechanism to Therapy

Mitophagy in acute central nervous system injuries: regulatory mechanisms and therapeutic potentials

Acute central nervous system injuries, including ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, traumatic brain injury, and spinal cord injury, are a major global health challenge. Identifying optimal therapies and improving the long-term neurological functions of patients with acute central nervous system injuries are urgent priorities. Mitochondria are susceptible to damage after acute central nervous system injury, and this leads to the release of toxic levels of reactive oxygen species, which induce cell death. Mitophagy, a selective form of autophagy, is crucial in eliminating redundant or damaged mitochondria during these events. Recent evidence has highlighted the significant role of mitophagy in acute central nervous system injuries. In this review, we provide a comprehensive overview of the process, classification, and related mechanisms of mitophagy. We also highlight the recent developments in research into the role of mitophagy in various acute central nervous system injuries and drug therapies that regulate mitophagy. In the final section of this review, we emphasize the potential for treating these disorders by focusing on mitophagy and suggest future research paths in this area.

Role of mitophagy in intervertebral disc degeneration: A narrative review

OBJECTIVE

The pivotal role of mitophagy in the initiation and progression of intervertebral disc (IVD) degeneration (IDD) has become increasingly apparent due to a growing body of research on its pathogenesis. This review summarizes the role of mitophagy in IDD and the therapeutic potential of targeting this process.

DESIGN

This narrative review is divided into three parts: the regulatory mechanisms of mitophagy, the role of mitophagy in IDD, and the applications and prospects of mitophagy for the treatment of IDD.

RESULTS

Mitophagy protects cells against harmful external stimuli and plays a crucial protective role by promoting extracellular matrix (ECM) production, inhibiting ECM degradation, and reducing apoptosis, senescence, and cartilage endplate calcification. However, excessive mitophagy is often detrimental to cells. Currently, the regulatory mechanisms governing appropriate and excessive mitophagy remain unclear.

CONCLUSIONS

Proper mitophagy effectively maintains IVD cell homeostasis and slows the progression of IDD. Conversely, excessive mitophagy may accelerate IDD development. Further research is needed to elucidate the regulatory mechanisms underlying appropriate and excessive mitophagy, which could provide new theoretical support for the application of mitophagy targeting to the treatment of IDD.

From mitochondrial dysfunction to neuroinflammation in Parkinson's disease: Pathogenesis and mitochondrial therapeutic approaches

Parkinson's disease (PD) is a prevalent and intricate neurological condition resulting from a combination of several factors, such as genetics, environment, and the natural process of aging. Degeneration of neurons in the substantia nigra pars compacta (SN) can cause motor and non-motor impairments in patients with PD. In PD's etiology, inflammation and mitochondrial dysfunction play significant roles in the disease's development. Studies of individuals with PD have revealed increased inflammation in various brain areas. Furthermore, mitochondrial dysfunction is an essential part of PD pathophysiology. Defects in the components of the mitochondrial nucleus, its membrane or internal signaling pathways, mitochondrial homeostasis, and morphological alterations in peripheral cells have been extensively documented in PD patients. According to these studies, neuroinflammation and mitochondrial dysfunction are closely connected as pathogenic conditions in neurodegenerative diseases like PD. Given the mitochondria's role in cellular homeostasis maintenance in response to membrane structural flaws or mutations in mitochondrial DNA, their dynamic nature may present therapeutic prospects in this area. Recent research investigates mitochondrial transplantation as a potential treatment for Parkinson's disease in damaged neurons. This review delves into the impact of inflammation and mitochondrial dysfunction on PD occurrence, treatment approaches, and the latest developments in mitochondrial transplantation, highlighting the potential consequences of these discoveries.

Chemoproteomic profiling by bioorthogonal probes to reveal the novel targets of acrylamide in microglia

Neurotoxicity studies caused by exposure to acrylamide (AA) are of wide interest, but the methods for direct analysis of AA targets in living neuronal cells by cysteine profiling are still lacking. To address this, we developed a specific bioorthogonal probe, AAPA-P2, for chemical proteomics analysis of AA covalent binding sites. AAPA-P2 captured 754 target proteins, increasing the number of identified target proteins by 20-fold. Further screening revealed 96 proteins that are both highly sensitive and heavily modified by AAPA-P2, with validation performed on some potential key targets and binding sites. AA was found to induce neurotoxicity by binding to newly identified targets, Proteasome 26S Subunit, non ATPase 9 (PSMD9) and NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 5 (NDUFA5), interfering with the ubiquitin-proteasome system, and inducing mitochondria-dependent apoptosis. The present work provides an effective bioorthogonal probe tool for identifying covalent binding targets of acrylamide and offers new insights into the molecular mechanisms underlying acrylamide-induced neurotoxicity.

Revolutionizing our understanding of Parkinson's disease: Dr. Heinz Reichmann's pioneering research and future research direction

Millions of individuals around the world are afflicted with Parkinson's disease (PD), a prevalent and incapacitating neurodegenerative disorder. Dr. Reichmann, a distinguished professor and neurologist, has made substantial advancements in the domain of PD research, encompassing both fundamental scientific investigations and practical applications. His research has illuminated the etiology and treatment of PD, as well as the function of energy metabolism and premotor symptoms. As a precursor to a number of neurotransmitters and neuromodulators that are implicated in the pathophysiology of PD, he has also investigated the application of tryptophan (Trp) derivatives in the disease. His principal findings and insights are summarized and synthesized in this narrative review article, which also emphasizes the challenges and implications for future PD research. This narrative review aims to identify and analyze the key contributions of Reichmann to the field of PD research, with the ultimate goal of informing future research directions in the domain. By examining Reichmann's work, the study seeks to provide a comprehensive understanding of his major contributions and how they can be applied to advance the diagnosis and treatment of PD. This paper also explores the potential intersection of Reichmann's findings with emerging avenues, such as the investigation of Trp and its metabolites, particularly kynurenines, which could lead to new insights and potential therapeutic strategies for managing neurodegenerative disorders like PD.

Ginsenoside Rg1: A Neuroprotective Natural Dammarane-Type Triterpenoid Saponin With Anti-Depressive Properties

BACKGROUND

Depression, a widespread mental disorder, presents significant risks to both physical and mental health due to its high rates of recurrence and suicide. Currently, single-target antidepressants typically alleviate depressive symptoms or delay the progression of depression rather than cure it. Ginsenoside Rg1 is one of the main ginsenosides found in Panax ginseng roots. It improves depressive symptoms through various mechanisms, suggesting its potential as a treatment for depression.

MATERIALS AND METHODS

We evaluated preclinical studies to comprehensively discuss the antidepressant mechanism of ginsenoside Rg1 and review its toxicity and medicinal value. Additionally, pharmacological network and molecular docking analyses were performed to further validate the antidepressant effects of ginsenoside Rg1.

RESULTS

The antidepressant mechanism of ginsenoside Rg1 may involve various pharmacological mechanisms and pathways, such as inhibiting neuroinflammation and over-activation of microglia, preserving nerve synapse structure, promoting neurogenesis, regulating monoamine neurotransmitter levels, inhibiting hyperfunction of the hypothalamic-pituitary-adrenal axis, and combatting antioxidative stress. Moreover, ginsenoside Rg1 preserves astrocyte gap junction function by regulating connexin43 protein biosynthesis and degradation, contributing to its antidepressant effect. Pharmacological network and molecular docking studies identified five targets (AKT1, STAT3, EGFR, PPARG, and HSP90AA1) as potential molecular regulatory sites of ginsenoside Rg1.

CONCLUSIONS

Ginsenoside Rg1 may exert its antidepressant effects via various pharmacological mechanisms. In addition, multicenter clinical case-control and molecular targeted studies are required to confirm both the clinical efficacy of ginsenoside Rg1 and its potential direct targets.

Mitochondrial dysfunction as a therapeutic strategy for neurodegenerative diseases: Current insights and future directions

Neurodegenerative diseases, as common diseases in the elderly, tend to become younger due to environmental changes, social development and other factors. They are mainly characterized by progressive loss or dysfunction of neurons in the central or peripheral nervous system, and common diseases include Parkinson's disease, Alzheimer's disease, Huntington's disease and so on. Mitochondria are important organelles for adenosine triphosphate (ATP) production in the brain. In recent years, a large amount of evidence has shown that mitochondrial dysfunction plays a direct role in neurodegenerative diseases, which is expected to provide new ideas for the treatment of related diseases. This review will summarize the main mechanisms of mitochondrial dysfunction in neurodegenerative diseases, as well as collating recent advances in the study of mitochondrial disorders and new therapies.

Targeted Liposomal Co-Delivery Dopamine with 3-n-Butylphthalide for Effective Against Parkinson's Disease in Mice Model

Introduction

Parkinson's disease (PD) is a multifactor-induced neurodegenerative disease with high incidence in the elderly population. We found for the first time that the combination of dopamine (DA) and 3-n-butylphthalide (NBP) has great potential for the synergistic treatment of PD. To further improve the therapeutic performance of the drugs, a brain-targeting liposomal co-delivery system encapsulating NBP and DA ((NBP+DA)-Lips-RVG29) was designed using a rabies virus polypeptide with 29 amino acids (RVG29) as the targeting ligand.

Methods

The synergistic neuroprotective effects of NBP and DA were assessed in 6-OHDA-induced PC12 cells. Then, (NBP+DA)-Lips-RVG29 loading with NBP and DA at an optimal ratio was prepared using the thin-film hydration and sonication method. The physicochemical and biological characterization of (NBP+DA)-Lips-RVG29 were systemically investigated, and the therapeutic efficiency and underlying mechanisms of (NBP+DA)-Lips-RVG29 were also explored in vitro and in vivo. Finally, the safety of (NBP+DA)-Lips-RVG29 was evaluated.

Results

The synergistic effects of NBP and DA peaked at 1:1 (NBP/DA, mol/mol). The functionalized liposomes showed significantly higher uptake efficiency and blood-brain barrier (BBB) penetration efficiency in vitro. After systemic administration, (NBP+DA)-Lips-RVG29 prolonged the blood circulation of drugs, enhanced BBB penetration and increased drug accumulation in the striatum, substantia nigra and hippocampus. Moreover, (NBP+DA)-Lips-RVG29 showed excellent neuroprotective effects in a cellular PD model of PC12 cells and improved therapeutic efficacy in a PD mouse model. Furthermore, the safety evaluation of (NBP+DA)-Lips-RVG29 revealed no systemic toxicity.

Conclusion

NBP and DA exhibited the synergistic anti-PD effects. The RVG29-modified liposomes encapsulating NBP and DA contributed to the accumulation of drugs in the brain lesions area of PD and further improved treatment efficacy. Therefore, (NBP+DA)-Lips-RVG29 represents a promising strategy for the treatment of PD and other neurodegenerative diseases.

Mechanistic exploration of ubiquitination-mediated pathways in cerebral ischemic injury

The ubiquitin-proteasome system (UPS) plays a pivotal role in regulating protein homeostasis and cellular processes, including protein degradation, trafficking, DNA repair, and cell signaling. During cerebral ischemia, ischemic conditions profoundly disrupt UPS activity, leading to proteasomal dysfunction and the accumulation of abnormal proteins. This imbalance contributes to neuronal injury and cell death observed in ischemic stroke. The UPS is intricately linked to various signaling pathways crucial for neuronal survival, inflammation, and cellular stress response, such as NF-κB, TRIM, TRIP, JAK-STAT, PI3K/Akt, and ERK1/2. Alterations in the ubiquitination process can significantly impact the activation and regulation of these pathways, exacerbating ischemic brain injury. Therapeutic approaches targeting the UPS in cerebral ischemia aim to rebalance protein levels, reduce proteotoxic stress, and mitigate neuronal injury. Strategies include proteasome inhibition, targeting specific ubiquitin ligases and deubiquitinating enzymes, and modulating ubiquitination-mediated regulation of key signaling pathways implicated in ischemia-induced pathophysiology. Therefore, the present review discusses the molecular mechanisms underlying UPS dysfunction in ischemic stroke is crucial for developing effective therapeutic interventions. Modulating ubiquitination-mediated pathways through therapeutic interventions targeting specific UPS components holds significant promise for mitigating ischemic brain injury and promoting neuroprotection and functional recovery in patients with cerebral ischemia.

When do the pathological signs become evident? Study of human mesenchymal stem cells in MDPL syndrome

Aging syndromes are rare genetic disorders sharing the features of accelerated senescence. Among these, Mandibular hypoplasia, Deafness and Progeroid features with concomitant Lipodystrophy (MDPL; OMIM #615381) is a rare autosomal dominant disease due to a de novo in-frame deletion in POLD1 gene, encoding the catalytic subunit of DNA polymerase delta. Here, we investigated how MSCs may contribute to the phenotypes and progression of premature aging syndromes such as MDPL. In human induced pluripotent stem cells (hiPSCs)-derived MSCs of three MDPL patients we detected several hallmarks of senescence, including (i) abnormal nuclear morphology, (ii) micronuclei presence, (iii) slow cell proliferation and cell cycle progression, (iv) reduced telomere length, and (v) increased levels of mitochondrial reactive oxygen species (ROS). We newly demonstrated that the pathological hallmarks of senescence manifest at an early stage of human development and represent a warning sign for the progression of the disease. Dissecting the mechanisms underlying stem cell dysfunction during aging can thereby contribute to the development of timely pharmacological therapies for ameliorating the pathological phenotype.

Mitophagy Unveiled: Exploring the Nexus of Mitochondrial Health and Neuroendocrinopathy

Mitochondria play a pivotal role in cellular metabolism, energy production, and apoptotic signaling, making mitophagy, the selective degradation of damaged mitochondria, crucial for mitochondrial health. Dysregulation of mitophagy has been implicated in various neuroendocrinopathies, yet the mechanisms linking these processes remain poorly understood. This review aims to explore the intersection between mitophagy and neuroendocrinopathy, addressing the critical gaps in knowledge regarding how mitochondrial dysfunction may contribute to the pathophysiology of neuroendocrine disorders. We conducted a comprehensive literature review of studies published on mitophagy and neuroendocrinopathies, focusing on data that elucidate the pathways involved and the clinical implications of mitochondrial health in neuroendocrine contexts. Our findings indicate that altered mitophagy may lead to the accumulation of dysfunctional mitochondria, contributing to neuroendocrine dysregulation. We present evidence linking impaired mitochondrial clearance to disease models of conditions such as metabolic syndrome, depression, and stress-related disorders, highlighting the potential for therapeutic interventions targeting mitophagy. While significant advances have been made in understanding mitochondrial biology, the direct interplay between mitophagy and neuroendocrinopathies remains underexplored. This review underscores the necessity for further research to elucidate these connections, which may offer novel insights into disease mechanisms and therapeutic strategies for treating maladaptive neuroendocrine responses.

Loss of function in Drosophila transcription factor Dif delays brain development in larvae resulting in aging adult brain

Drosophila NF-κB transcription factor Dif has been well known for its function in innate immunity, and recent study also reveals its role in neuronal cells. However, the underlying mechanisms of Dif in the brain remain elusive. In this study, we aim to investigate the function of Dif in Drosophila brain development and how Dif regulates structure and plasticity of the brain to affect aging and behaviors. Based on the analysis of differentially expressed genes, we identified key genes associated with cell division, development and aging in the brain of Dif1 loss of function mutant. In Dif1 larvae, we found that the metamorphosis and brain development were delayed, and cell division was decreased. In Dif1 adults, the number of neuron cells was reduced in the brain, the lifespan and locomotor activity were decreased, protein markers associated with aging-related neurodegenerative diseases in the brain were altered in abundance or activity. Our results indicated that Dif plays a crucial role in brain plasticity and neurogenesis, dysfunction of Dif delays larval brain development and impacts proliferation of neuronal cells, resulting in aging adult brain by regulating expression of key genes in multiple signaling pathways involved in cell division, neurogenesis and aging.

Targeting mitochondria with small molecules: A promising strategy for combating Parkinson's disease

Parkinson's disease (PD), a neurodegenerative disorder, is one of the most significant challenges confronting modern societies, affecting millions of patients globally each year. The pathophysiology of PD is significantly influenced by mitochondrial dysfunction, as evident by the contribution of altered mitochondrial dynamics, bioenergetics, and increased oxidative stress to neuronal death. This review examines the potential use of small molecules that target mitochondria as a therapeutic approach for treating PD. Progress in mitochondrial biology has revealed various mitochondrial targets that can be modulated to restore function and mitigate neurodegeneration. Small molecules that promote mitochondrial biogenesis, enhance mitochondrial dynamics, decrease oxidative stress, and prevent the opening of the mitochondrial permeability transition pore (mPTP) have shown promise in preclinical models. Additionally, targeting mitochondrial quality control mechanisms, such as mitophagy, provides another therapeutic approach. This review explores recent research on small molecules targeting mitochondria, examines their mechanisms of action, and assesses their potential efficacy and safety profiles. By highlighting the most promising candidates and addressing the challenges and future directions in this field, this review aims to offer a comprehensive overview of current and future prospects for mitochondrial-targeted therapies in PD. Ultimately, treating mitochondrial dysfunction holds significant promise for developing disease-modifying PD medications, giving patients hope for better outcomes and improved quality of life.

Brain-wide alterations revealed by spatial transcriptomics and proteomics in COVID-19 infection

Understanding the pathophysiology of neurological symptoms observed after severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection is essential to optimizing outcomes and therapeutics. To date, small sample sizes and narrow molecular profiling have limited the generalizability of findings. In this study, we profiled multiple cortical and subcortical regions in postmortem brains of patients with coronavirus disease 2019 (COVID-19) and controls with matched pulmonary pathology (total n = 42) using spatial transcriptomics, bulk gene expression and proteomics. We observed a multi-regional antiviral response without direct active SARS-CoV2 infection. We identified dysregulation of mitochondrial and synaptic pathways in deep-layer excitatory neurons and upregulation of neuroinflammation in glia, consistent across both mRNA and protein. Remarkably, these alterations overlapped substantially with changes in age-related neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease. Our work, combining multiple experimental and analytical methods, demonstrates the brain-wide impact of severe acute/subacute COVID-19, involving both cortical and subcortical regions, shedding light on potential therapeutic targets within pathways typically associated with pathological aging and neurodegeneration.

Liquid-liquid phase separation and conformational strains of α-Synuclein: implications for Parkinson's disease pathogenesis

Parkinson's disease (PD) and other synucleinopathies are characterized by the aggregation and deposition of alpha-synuclein (α-syn) in brain cells, forming insoluble inclusions such as Lewy bodies (LBs) and Lewy neurites (LNs). The aggregation of α-syn is a complex process involving the structural conversion from its native random coil to well-defined secondary structures rich in β-sheets, forming amyloid-like fibrils. Evidence suggests that intermediate species of α-syn aggregates formed during this conversion are responsible for cell death. However, the molecular events involved in α-syn aggregation and its relationship with disease onset and progression remain not fully elucidated. Additionally, the clinical and pathological heterogeneity observed in various synucleinopathies has been highlighted. Liquid-liquid phase separation (LLPS) and condensate formation have been proposed as alternative mechanisms that could underpin α-syn pathology and contribute to the heterogeneity seen in synucleinopathies. This review focuses on the role of the cellular environment in α-syn conformational rearrangement, which may lead to pathology and the existence of different α-syn conformational strains with varying toxicity patterns. The discussion will include cellular stress, abnormal LLPS formation, and the potential role of LLPS in α-syn pathology.

AAV-aMTD-Parkin, a therapeutic gene delivery cargo, enhances motor and cognitive functions in Parkinson's and Alzheimer's diseases

Neurodegenerative disorders, such as Parkinson's disease (PD) and Alzheimer's disease (AD), have a global prevalence and profoundly impact both motor and cognitive functions. Although adeno-associated virus (AAV)-based gene therapy has shown promise, its application for treating central nervous system (CNS) diseases faces several challenges, including effective delivery of AAV vectors across the blood-brain barrier, determining optimal dosages, and achieving targeted distribution. To address these challenges, we have developed a fusion delivery therapeutic cargo called AAV-aMTD-Parkin, which combines a hydrophobic cell-penetrating peptide sequence with the DNA sequences of AAV and Parkin. By employing this fusion delivery platform at lower dosages compared to zolgensma, we have achieved significant enhancements in cell and tissue permeability, while reducing the occurrence of common pathological protein aggregates. Consequently, motor and cognitive functions were restored in animal models of PD and AD. With its dual functionality in addressing PD and AD, AAV-aMTD-Parkin holds immense potential as a novel class of therapeutic biologics for prevalent CNS diseases.

Associations between Thyroid Hormones and Cognitive Impairment in Patients with Parkinson's Disease

This study aims to explore the correlation of serum thyroid hormone levels to cognitive impairments in Parkinson's disease (PD) patients. In this retrospective study, 106 Chinese patients without cognitive impairments and 94 patients with cognitive impairments, including 55 with mild cognitive impairment (PD-MCI) and 39 with PD dementia (PDD), were analyzed. Clinical data regarding the PD assessments, including disease duration, Unified Parkinson's Disease Rating Scale (UPDRS) Part 3 scores, and Hoehn and Yahr (H-Y) staging, were analyzed. Cognitive functions were evaluated using the Montreal Cognitive Assessment score. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3), were measured using ELISA. Significantly altered H-Y staging, disease duration, and UPDRS Part 3 scores were observed in PD patients with cognitive impairment compared with those without. Serum levels of FT3 were significantly decreased, while FT4 and TSH levels were significantly elevated in PD patients with cognitive impairment compared with those without. Combined detection of TSH, FT3, and FT4 showed value in distinguishing PD patients with and without cognitive impairment. Furthermore, a comparison of serum levels between PD-MCI and PDD patients revealed significant association between thyroid hormone levels and the degree of cognitive impairment in PD patients. Our findings suggest a relationship between changes in serum thyroid hormone levels and cognitive impairments in PD patients. Thyroid hormone levels, particularly FT3, may serve as potential markers for cognitive dysfunction in PD.

Unraveling neuroprotection in Parkinson's disease: Nrf2-Keap1 pathway's vital role amidst pathogenic pathways

Parkinson's disease (PD) is an age-related chronic neurological condition characterized by progressive degeneration of dopaminergic neurons and the presence of Lewy bodies, primarily composed of alpha-synuclein and ubiquitin. The pathophysiology of PD encompasses alpha-synuclein aggregation, oxidative stress, neuroinflammation, mitochondrial dysfunction, and impaired autophagy and ubiquitin-proteasome systems. Among these, the Keap1-Nrf2 pathway is a key regulator of antioxidant defense mechanisms. Nrf2 has emerged as a crucial factor in managing oxidative stress and inflammation, and it also influences ubiquitination through p62 expression. Keap1 negatively regulates Nrf2 by targeting it for degradation via the ubiquitin-proteasome system. Disruption of the Nrf2-Keap1 pathway in PD affects cellular responses to oxidative stress and inflammation, thereby playing a critical role in disease progression. In addition, the role of neuroinflammation in PD has gained significant attention, highlighting the interplay between immune responses and neurodegeneration. This review discusses the various mechanisms responsible for neuronal degeneration in PD, with a special emphasis on the neuroprotective role of the Nrf2-Keap1 pathway. Furthermore, it explores the implications of inflammopharmacology in modulating these pathways to provide therapeutic insights for PD.

Loss of CHCHD2 Stability Coordinates with C1QBP/CHCHD2/CHCHD10 Complex Impairment to Mediate PD-Linked Mitochondrial Dysfunction

Novel CHCHD2 mutations causing C-terminal truncation and interrupted CHCHD2 protein stability in Parkinson's disease (PD) patients were previously found. However, there is limited understanding of the underlying mechanism and impact of subsequent CHCHD2 loss-of-function on PD pathogenesis. The current study further identified the crucial motif (aa125-133) responsible for diminished CHCHD2 expression and the molecular interplay within the C1QBP/CHCHD2/CHCHD10 complex to regulate mitochondrial functions. Specifically, CHCHD2 deficiency led to decreased neural cell viability and mitochondrial structural and functional impairments, paralleling the upregulation of autophagy under cellular stresses. Meanwhile, as a binding partner of CHCHD2, C1QBP was found to regulate the stability of CHCHD2 and CHCHD10 proteins to maintain the integrity of the C1QBP/CHCHD2/CHCHD10 complex. Moreover, C1QBP-silenced neural cells displayed severe cell death phenotype along with mitochondrial damage that initiated a significant mitophagy process. Taken together, the evidence obtained from our in vitro and in vivo studies emphasized the critical role of CHCHD2 in regulating mitochondria functions via coordination among CHCHD2, CHCHD10, and C1QBP, suggesting the potential mechanism by which CHCHD2 function loss takes part in the progression of neurodegenerative diseases.

Identification of Potential Causal Genes for Neurodegenerative Diseases by Mitochondria-Related Genome-Wide Mendelian Randomization

Current research lacks comprehensive investigations into the potential causal link between mitochondrial-related genes and the risk of neurodegenerative diseases (NDDs). We aimed to identify potential causative genes for five NDDs through an examination of mitochondrial-related gene expression levels. Through the integration of summary statistics from expression quantitative trait loci (eQTL) datasets (human blood and brain tissue), mitochondrial DNA copy number (mtDNA-CN), and genome-wide association studies (GWAS) datasets of five NDDs from European ancestry, we conducted a Mendelian randomization (MR) analysis to explore the potential causal relationship between mitochondrial-related genes and Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Lewy body dementia (LBD). Sensitivity analysis and Bayesian colocalization were employed to validate this causal relationship. Through MR analysis, we have identified potential causal relationships between 12 mitochondria-related genes and AD, PD, ALS, and FTD overlapping with motor neuron disease (FTD_MND) in human blood or brain tissue. Bayesian colocalization analysis further confirms 9 causal genes, including NDUFS2, EARS2, and MRPL41 for AD; NDUFAF2, MALSU1, and METTL8 for PD; MYO19 and MRM1 for ALS; and FASTKD1 for FTD_MND. Importantly, in both human blood and brain tissue, NDUFS2 exhibits a significant pathogenic effect on AD, while NDUFAF2 demonstrates a robust protective effect on PD. Additionally, the mtDNA-CN plays a protected role in LBD (OR = 0.62, p = 0.031). This study presents evidence establishing a causal relationship between mitochondrial dysfunction and NDDs. Furthermore, the identified candidate genes may serve as potential targets for drug development aimed at preventing NDDs.

New Insights into Mitochondria in Health and Diseases

Mitochondria are a unique type of semi-autonomous organelle within the cell that carry out essential functions crucial for the cell's survival and well-being. They are the location where eukaryotic cells carry out energy metabolism. Aside from producing the majority of ATP through oxidative phosphorylation, which provides essential energy for cellular functions, mitochondria also participate in other metabolic processes within the cell, such as the electron transport chain, citric acid cycle, and β-oxidation of fatty acids. Furthermore, mitochondria regulate the production and elimination of ROS, the synthesis of nucleotides and amino acids, the balance of calcium ions, and the process of cell death. Therefore, it is widely accepted that mitochondrial dysfunction is a factor that causes or contributes to the development and advancement of various diseases. These include common systemic diseases, such as aging, diabetes, Parkinson's disease, and cancer, as well as rare metabolic disorders, like Kearns-Sayre syndrome, Leigh disease, and mitochondrial myopathy. This overview outlines the various mechanisms by which mitochondria are involved in numerous illnesses and cellular physiological activities. Additionally, it provides new discoveries regarding the involvement of mitochondria in both disorders and the maintenance of good health.

Clinical, mechanistic, biomarker, and therapeutic advances in GBA1-associated Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease. The development of PD is closely linked to genetic and environmental factors, with GBA1 variants being the most common genetic risk. Mutations in the GBA1 gene lead to reduced activity of the coded enzyme, glucocerebrosidase, which mediates the development of PD by affecting lipid metabolism (especially sphingolipids), lysosomal autophagy, endoplasmic reticulum, as well as mitochondrial and other cellular functions. Clinically, PD with GBA1 mutations (GBA1-PD) is characterized by particular features regarding the progression of symptom severity. On the therapeutic side, the discovery of the relationship between GBA1 variants and PD offers an opportunity for targeted therapeutic interventions. In this review, we explore the genotypic and phenotypic correlations, etiologic mechanisms, biomarkers, and therapeutic approaches of GBA1-PD and summarize the current state of research and its challenges.

CHCHD2 mutant mice display mitochondrial protein accumulation and disrupted energy metabolism

Mutations in the mitochondrial cristae protein CHCHD2 lead to a late-onset autosomal dominant form of Parkinson's disease (PD) which closely resembles idiopathic PD, providing the opportunity to gain new insights into the mechanisms of mitochondrial dysfunction contributing to PD. To begin to address this, we used CRISPR genome-editing to generate CHCHD2 T61I point mutant mice. CHCHD2 T61I mice had normal viability, and had only subtle motor deficits with no signs of premature dopaminergic (DA) neuron degeneration. Nonetheless, CHCHD2 T61I mice exhibited robust molecular changes in the brain including increased CHCHD2 insolubility, accumulation of CHCHD2 protein preferentially in the substantia nigra (SN), and elevated levels of α-synuclein. Metabolic analyses revealed an increase in glucose metabolism through glycolysis relative to the TCA cycle with increased respiratory exchange ratio, and immune-electron microscopy revelated disrupted mitochondria in DA neurons. Moreover, spatial genomics revealed decreased expression of mitochondrial complex I and III respiratory chain proteins, while proteomics revealed increased respiratory chain and other mitochondrial protein-protein interactions. As such, the CHCHD2 T61I point-mutation mice exhibit robust mitochondrial disruption and a consequent metabolic shift towards glycolysis. These findings thus establish CHCHD2 T61I mice as a new model for mitochondrial-based PD, and implicate disrupted respiratory chain function as a likely causative driver.

The Bifunctional Dimer Caffeine-Indan Attenuates α-Synuclein Misfolding, Neurodegeneration and Behavioral Deficits after Chronic Stimulation of Adenosine A1 Receptors

We previously found that chronic adenosine A1 receptor stimulation with N6-Cyclopentyladenosine increased α-synuclein misfolding and neurodegeneration in a novel α-synucleinopathy model, a hallmark of Parkinson's disease. Here, we aimed to synthesize a dimer caffeine-indan linked by a 6-carbon chain to cross the blood-brain barrier and tested its ability to bind α-synuclein, reducing misfolding, behavioral abnormalities, and neurodegeneration in our rodent model. Behavioral tests and histological stains assessed neuroprotective effects of the dimer compound. A rapid synthesis of the 18F-labeled analogue enabled Positron Emission Tomography and Computed Tomography imaging for biodistribution measurement. Molecular docking analysis showed that the dimer binds to α-synuclein N- and C-termini and the non-amyloid-β-component (NAC) domain, similar to 1-aminoindan, and this binding promotes a neuroprotective α-synuclein "loop" conformation. The dimer also binds to the orthosteric binding site for adenosine within the adenosine A1 receptor. Immunohistochemistry and confocal imaging showed the dimer abolished α-synuclein upregulation and aggregation in the substantia nigra and hippocampus, and the dimer mitigated cognitive deficits, anxiety, despair, and motor abnormalities. The 18F-labeled dimer remained stable post-injection and distributed in various organs, notably in the brain, suggesting its potential as a Positron Emission Tomography tracer for α-synuclein and adenosine A1 receptor in Parkinson's disease therapy.

Unraveling mitochondrial dysfunction: comprehensive perspectives on its impact on neurodegenerative diseases

Neurodegenerative diseases represent a significant challenge to modern medicine, with their complex etiology and progressive nature posing hurdles to effective treatment strategies. Among the various contributing factors, mitochondrial dysfunction has emerged as a pivotal player in the pathogenesis of several neurodegenerative disorders. This review paper provides a comprehensive overview of how mitochondrial impairment contributes to the development of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, driven by bioenergetic defects, biogenesis impairment, alterations in mitochondrial dynamics (such as fusion or fission), disruptions in calcium buffering, lipid metabolism dysregulation and mitophagy dysfunction. It also covers current therapeutic interventions targeting mitochondrial dysfunction in these diseases.

Klotho: molecular mechanisms and emerging therapeutics in central nervous system diseases

Klotho is recognized as an aging-suppressor protein that is implicated in a variety of processes and signaling pathways. The anti-inflammatory, anti-apoptotic, anti-oxidant, and anti-tumor bioactivities of klotho have extended its application in neurosciences and made the protein popular for its lifespan-extending capacity. Furthermore, it has been demonstrated that klotho levels would reduce with aging and numerous pathologies, particularly those related to the central nervous system (CNS). Evidence supports the idea that klotho can be a key therapeutic target in CNS diseases such as amyotrophic lateral sclerosis, Parkinson's disease, stroke, and Alzheimer's disease. Reviewing the literature suggests that the upregulation of klotho expression regulates various signaling pathways related to autophagy, oxidative stress, inflammation, cognition, and ferroptosis in neurological disorders. Therefore, it has been of great interest to develop drugs or agents that boost or restore klotho levels. In this regard, the present review was designed and aimed to gather the delegated documents regarding the therapeutic potential of Klotho in CNS diseases focusing on the molecular and cellular mechanisms.

Dendritic cells in Parkinson's disease: Regulatory role and therapeutic potential

Parkinson's Disease (PD) is a debilitating neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons and the presence of Lewy bodies. While the traditional focus has been on neuronal and glial cell dysfunction, recent research has shifted towards understanding the role of the immune system, particularly dendritic cells (DCs), in PD pathogenesis. As pivotal antigen-presenting cells, DCs are traditionally recognized for initiating and regulating immune responses. In PD, DCs contribute to disease progression through the presentation of α-synuclein to T cells, leading to an adaptive immune response against neuronal elements. This review explores the emerging role of DCs in PD, highlighting their potential involvement in antigen presentation and T cell immune response modulation. Understanding the multifaceted functions of DCs could reveal novel insights into PD pathogenesis and open new avenues for therapeutic strategies, potentially altering the course of this devastating disease.

Palmatine Ameliorates Motor Deficits and Dopaminergic Neuron Loss by Regulating NLRP3 Inflammasome through Mitophagy in Parkinson's Disease Model Mice

NLRP3 inflammasomes-mediated proinflammatory response and mitochondrial dysfunction play a critical role in the etiology and pathogenesis of Parkinson's disease. Negative regulation of NLRP3 inflammasome activation through mitophagy may be an important strategy to control NLRP3 inflammasome-mediated proinflammatory responses. Palmatine (PAL), an isoquinoline alkaloid found in various of plants, has potent pharmacological effects such as anti-inflammatory and anti-oxidation. However, the specific role of PAL in the pathology of Parkinson's disease remains unclear. In this study, we found that treatment with PAL improved motor deficits and reduced the loss of dopaminergic neurons in MPTP mice. Further results showed that PAL promoted mitophagy and inhibited the proinflammatory response mediated by NLRP3 inflammasomes. In addition, chloroquine (CQ, mitophagy inhibitor) attenuated the ameliorative effects of PAL on the motor deficits and dopaminergic neuron damage, as well as the inhibitory effect of PAL on NLRP3 inflammasome. Collectively, these results provide strong evidence that PAL ameliorates motor deficits and dopaminergic neuron death in Parkinson's disease, and the mechanism may be related to its inhibition of NLRP3 inflammasome activation via promoting mitophagy.

An update on novel and emerging therapeutic targets in Parkinson's disease

Parkinson's Disease (PD) remains a significant focus of extensive research aimed at developing effective therapeutic strategies. Current treatments primarily target symptom management, with limited success in altering the course of the disease. This shortfall underscores the urgent need for novel therapeutic approaches that can modify the progression of PD.This review concentrates on emerging therapeutic targets poised to address the underlying mechanisms of PD. Highlighted novel and emerging targets include Protein Abelson, Rabphilin-3 A, Colony Stimulating Factor 1-Receptor, and Apelin, each showing promising potential in preclinical and clinical settings for their ability to modulate disease progression. By examining recent advancements and outcomes from trials focusing on these targets, the review aims to elucidate their efficacy and potential as disease-modifying therapies.Furthermore, the review explores the concept of multi-target approaches, emphasizing their relevance in tackling the complex pathology of PD. By providing comprehensive insights into these novel targets and their therapeutic implications, this review aims to guide future research directions and clinical developments toward more effective treatments for PD and related neurodegenerative disorders.

The mechanism of lovastatin in suppressing the proliferation of esophageal squamous cell carcinoma based on proteomics

BACKGROUND

Lovastatin, a type of statin usually considered as a lipid-lowering drug that lowers blood cholesterol and low-density lipoprotein cholesterol levels, has been rediscovered to have anticancer activity. Fewer studies exist regarding the effect of lovastatin on esophageal squamous cell carcinoma (ESCC).

METHODS

Here, we report that lovastatin shows anticancer effect on ESCC By affecting the mitochondrial autophagy pathway. Moreover, based on proteomics and computer molecular simulations found that RAB38 and RAB27A may be a target of lovastatin.

RESULTS

We observed that autophagy of mitochondria is inhibited by lovastatin, affecting esophageal squamous cell proliferation. There is a possible link between the expression of RAB38, RAB27A and immune cell invasion in esophageal cancer.

CONCLUSIONS

These results demonstrate the huge potential of lovastatin as an RAB38, RAB27A inhibitor in esophageal cancer chemotherapy and chemoprevention.

Association of Autoimmune Diseases with the Risk of Parkinson's Disease

INTRODUCTION

PD is a progressive neurodegeneration disease characterized by cardinal motor symptoms such as bradykinesia and tremor. The pathogenesis of PD remains unclear. It is hypothesized that immune system dysfunction may contribute to PD. Thus, autoimmune diseases may influence the risk of incident PD.

METHODS

We included 398,329 participants without PD at the baseline from UK Biobank. The association between 20 autoimmune diseases with PD was examined using cox hazards regression analyses, adjusting covariates like age, sex, and smoking status in the statistical models. Sensitivity analyses were conducted, adjusting for polygenic risk score and the reported source of PD, to check the robustness.

RESULTS

After an average follow-up of 13.1 ± 0.816 years, 2,245 participants were diagnosed with incident PD. After multiple comparison correction, only multiple sclerosis (MS) reached statistical significance and showed an increased risk for incident PD. Compared with non-MS patients, the risk of incident PD in MS patients was 2.57-fold with age and sex being adjusted (95% CI, 1.59-4.14; adjust p value = 0.002). After adjusting lifestyle and other factors, the hazard ratio of incident PD in MS patients was 2.49 (95% CI, 1.55-4.02; adjust p value = 0.004). Excluding the self-reported PD cases in the sensitivity analysis, MS was a detrimental factor for incident PD (HR, 2.06; 95% CI, 1.56-4.05; adjust p value = 0.004). The link between MS and PD did not reach the statistical significance in the sensitivity analysis adjusting the PRS (adjust p value = 0.95).

CONCLUSION

Our study provided evidence from observational analyses that MS was associated with an increased risk of PD. Further investigations should be performed to determine the causal association and potential pathophysiology between MS and PD.

High frequency electrical stimulation reduces α-synuclein levels and α-synuclein-mediated autophagy dysfunction

Accumulation of α-synuclein (α-Syn) has been implicated in proteasome and autophagy dysfunction in Parkinson's disease (PD). High frequency electrical stimulation (HFS) mimicking clinical parameters used for deep brain stimulation (DBS) in vitro or DBS in vivo in preclinical models of PD have been found to reduce levels of α-Syn and, in certain cases, provide possible neuroprotection. However, the mechanisms by which this reduction in α-Syn improves cellular dysfunction associated with α-Syn accumulation remains elusive. Using HFS parameters that recapitulate DBS in vitro, we found that HFS led to a reduction of mutant α-Syn and thereby limited proteasome and autophagy impairments due to α-Syn. Additionally, we observed that HFS modulates via the ATP6V0C subunit of V-ATPase and mitigates α-Syn mediated autophagic dysfunction. This study highlights a role for autophagy in reduction of α-Syn due to HFS which may prove to be a viable approach to decrease pathological protein accumulation in neurodegeneration.

Ruthenium red alleviates post-resuscitation myocardial dysfunction by upregulating mitophagy through inhibition of USP33 in a cardiac arrest rat model

Cardiac arrest (CA) remains a leading cause of death, with suboptimal survival rates despite efforts involving cardiopulmonary resuscitation and advanced life-support technology. Post-resuscitation myocardial dysfunction (PRMD) is an important determinant of patient outcomes. Myocardial ischemia/reperfusion injury underlies this dysfunction. Previous reports have shown that ruthenium red (RR) has a protective effect against cardiac ischemia-reperfusion injury; however, its precise mechanism of action in PRMD remains unclear. This study investigated the effects of RR on PRMD and analyzed its underlying mechanisms. Ventricular fibrillation was induced in rats, which were then subjected to cardiopulmonary resuscitation to establish an experimental CA model. At the onset of return of spontaneous circulation, RR (2.5 mg/kg) was administered intraperitoneally. Our study showed that RR improved myocardial function and reduced the production of oxidative stress markers such as malondialdehyde (MDA), glutathione peroxidase (GSSG), and reactive oxygen species (ROS) production. RR also helped maintain mitochondrial structure and increased ATP and GTP levels. Additionally, RR effectively attenuated myocardial apoptosis. Furthermore, we observed downregulation of proteins closely related to mitophagy, including ubiquitin-specific protease 33 (USP33) and P62, whereas LC3B (microtubule-associated protein light chain 3B) was upregulated. The upregulation of mitophagy may play a critical role in reducing myocardial injury. These results demonstrate that RR may attenuate PRMD by promoting mitophagy through the inhibition of USP33. These effects are likely mediated through diverse mechanisms, including antioxidant activity, apoptosis suppression, and preservation of mitochondrial integrity and energy metabolism. Consequently, RR has emerged as a promising therapeutic approach for addressing post-resuscitation myocardial dysfunction.

Emerging perspectives on precision therapy for Parkinson's disease: multidimensional evidence leading to a new breakthrough in personalized medicine

PD is a prevalent and progressive neurodegenerative disorder characterized by both motor and non-motor symptoms. Genes play a significant role in the onset and progression of the disease. While the complexity and pleiotropy of gene expression networks have posed challenges for gene-targeted therapies, numerous pathways of gene variant expression show promise as therapeutic targets in preclinical studies, with some already in clinical trials. With the recognition of the numerous genes and complex pathways that can influence PD, it may be possible to take a novel approach to choose a treatment for the condition. This approach would be based on the symptoms, genomics, and underlying mechanisms of the disease. We discuss the utilization of emerging genetic and pathological knowledge of PD patients to categorize the disease into subgroups. Our long-term objective is to generate new insights for the therapeutic approach to the disease, aiming to delay and treat it more effectively, and ultimately reduce the burden on individuals and society.

Protopanaxadiols Eliminate Behavioral Impairments and Mitochondrial Dysfunction in Parkinson's Disease Mice Model

Currently, there are no effective therapies to cure Parkinson's disease (PD), which is the second most common neurodegenerative disease primarily characterized by motor dysfunction and degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc). Protopanaxadiols (PPDs), including 20 (R)- protopanaxadiol (R-PPD) and 20 (S)- protopanaxadiol (S-PPD), are main metabolites of ginsenosides. The role of ginsenosides in neurodegenerative diseases has been thoroughly studied, however, it is unknown whether PPDs can attenuate behavioral deficits and dopaminergic neuron injury in PD model mice to date. Here, we administered PPDs to MPTP-induced PD model mice and monitored the effects on behavior and dopaminergic neurons to investigate the effects of R-PPD and S-PPD against PD. Our results showed that R-PPD and S-PPD (at a dose of 20 mg/kg, i.g.) treatment alleviated MPTP (30 mg/kg, i.p.) induced behavioral deficits. Besides, R-PPD and S-PPD protected MPP+-induced neuron injury and mitochondrial dysfunction, and reduced the abnormal expression of Cyt C, Bax, caspase-3 and Bcl-2. These findings demonstrate that R-PPD and S-PPD were potentially useful to ameliorate PD.

Polygenic Risk Scores Validated in Patient-Derived Cells Stratify for Mitochondrial Subtypes of Parkinson's Disease

OBJECTIVE

The aim of our study is to better understand the genetic architecture and pathological mechanisms underlying neurodegeneration in idiopathic Parkinson's disease (iPD). We hypothesized that a fraction of iPD patients may harbor a combination of common variants in nuclear-encoded mitochondrial genes ultimately resulting in neurodegeneration.

METHODS

We used mitochondria-specific polygenic risk scores (mitoPRSs) and created pathway-specific mitoPRSs using genotype data from different iPD case-control datasets worldwide, including the Luxembourg Parkinson's Study (412 iPD patients and 576 healthy controls) and COURAGE-PD cohorts (7,270 iPD cases and 6,819 healthy controls). Cellular models from individuals stratified according to the most significant mitoPRS were subsequently used to characterize different aspects of mitochondrial function.

RESULTS

Common variants in genes regulating Oxidative Phosphorylation (OXPHOS-PRS) were significantly associated with a higher PD risk in independent cohorts (Luxembourg Parkinson's Study odds ratio, OR = 1.31[1.14-1.50], p-value = 5.4e-04; COURAGE-PD OR = 1.23[1.18-1.27], p-value = 1.5e-29). Functional analyses in fibroblasts and induced pluripotent stem cells-derived neuronal progenitors revealed significant differences in mitochondrial respiration between iPD patients with high or low OXPHOS-PRS (p-values < 0.05). Clinically, iPD patients with high OXPHOS-PRS have a significantly earlier age at disease onset compared to low-risk patients (false discovery rate [FDR]-adj p-value = 0.015), similar to prototypic monogenic forms of PD. Finally, iPD patients with high OXPHOS-PRS responded more effectively to treatment with mitochondrially active ursodeoxycholic acid.

INTERPRETATION

OXPHOS-PRS may provide a precision medicine tool to stratify iPD patients into a pathogenic subgroup genetically defined by specific mitochondrial impairment, making these individuals eligible for future intelligent clinical trial designs. ANN NEUROL 2024;96:133-149.

Teaghrelin protected dopaminergic neurons in MPTP-induced Parkinson's disease animal model by promoting PINK1/Parkin-mediated mitophagy and AMPK/SIRT1/PGC1-α-mediated mitochondrial biogenesis

Mitochondrial dysfunction, a common cellular hallmark in both familial and sporadic forms of Parkinson's disease (PD), is assumed to play a significant role in pathologic development and progression of the disease. Teaghrelin, a unique bioactive compound in some oolong tea varieties, has been demonstrated to protect SH-SY5Y cells against 1-methyl-4-phenylpyridinium induced neurotoxicity by binding to the ghrelin receptor to activate the AMPK/SIRT1/PGC-1α pathway. In this study, an animal model was established using a neurotoxin, 1-methyl-4phenyl-1,2,3,6-tetrahydropyridine (MPTP), a byproduct of a prohibited drug, to evaluate the oral efficacy of teaghrelin on PD by monitoring motor dysfunction of mice in open field, pole, and bean walking tests. The results showed that MPTP-induced motor dysfunction of mice was significantly attenuated by teaghrelin supplementation. Tyrosine hydroxylase and dopamine transporter protein were found reduced in the striatum and midbrain of MPTP-treated mice, and significantly mitigated by teaghrelin supplementation. Furthermore, teaghrelin administration enhanced mitophagy and mitochondria biogenesis, which maintained cell homeostasis and prevented the accumulation of αSyn and apoptosis-related proteins. It seemed that teaghrelin protected dopaminergic neurons in MPTP-treated mice by increasing PINK1/Parkin-mediated mitophagy and AMPK/SIRT1/PGC-1α-mediated mitochondria biogenesis, highlighting its potential therapeutic role in maintaining dopaminergic neurons function in PD. Mitochondrial dysfunction, a common cellular hallmark in both familial and sporadic forms of Parkinson's disease (PD), is assumed to play a significant role in pathologic development and progression of the disease. Teaghrelin, a unique bioactive compound in some oolong tea varieties, has been demonstrated to protect SH-SY5Y cells against 1-methyl-4-phenylpyridinium induced neurotoxicity by binding to the ghrelin receptor to activate the AMPK/SIRT1/PGC-1α pathway. In this study, an animal model was established using a neurotoxin, 1-methyl-4phenyl-1,2,3,6-tetrahydropyridine (MPTP), a byproduct of a prohibited drug, to evaluate the oral efficacy of teaghrelin on PD by monitoring motor dysfunction of mice in open field, pole, and bean walking tests. The results showed that MPTP-induced motor dysfunction of mice was significantly attenuated by teaghrelin supplementation. Tyrosine hydroxylase and dopamine transporter protein were found reduced in the striatum and midbrain of MPTP-treated mice, and significantly mitigated by teaghrelin supplementation. Furthermore, teaghrelin administration enhanced mitophagy and mitochondria biogenesis, which maintained cell homeostasis and prevented the accumulation of αSyn and apoptosis-related proteins. It seemed that teaghrelin protected dopaminergic neurons in MPTP-treated mice by increasing PINK1/Parkin-mediated mitophagy and AMPK/SIRT1/PGC-1α-mediated mitochondria biogenesis, highlighting its potential therapeutic role in maintaining dopaminergic neurons function in PD.

From macroautophagy to mitophagy: Unveiling the hidden role of mitophagy in gastrointestinal disorders

In this editorial, we comment on an article titled “Morphological and biochemical characteristics associated with autophagy in gastrointestinal diseases”, which was published in a recent issue of the World Journal of Gastroenterology. We focused on the statement that “autophagy is closely related to the digestion, secretion, and regeneration of gastrointestinal cells”. With advancing research, autophagy, and particularly the pivotal role of the macroautophagy in maintaining cellular equilibrium and stress response in the gastrointestinal system, has garnered extensive study. However, the significance of mitophagy, a unique selective autophagy pathway with ubiquitin-dependent and independent variants, should not be overlooked. In recent decades, mitophagy has been shown to be closely related to the occurrence and development of gastrointestinal diseases, especially inflammatory bowel disease, gastric cancer, and colorectal cancer. The interplay between mitophagy and mitochondrial quality control is crucial for elucidating disease mechanisms, as well as for the development of novel treatment strategies. Exploring the pathogenesis behind gastrointestinal diseases and providing individualized and efficient treatment for patients are subjects we have been exploring. This article reviews the potential mechanism of mitophagy in gastrointestinal diseases with the hope of providing new ideas for diagnosis and treatment.

PSMF1 variants cause a phenotypic spectrum from early-onset Parkinson's disease to perinatal lethality by disrupting mitochondrial pathways

Dissecting biological pathways highlighted by Mendelian gene discovery has provided critical insights into the pathogenesis of Parkinson's disease (PD) and neurodegeneration. This approach ultimately catalyzes the identification of potential biomarkers and therapeutic targets. Here, we identify PSMF1 as a new gene implicated in PD and childhood neurodegeneration. We find that biallelic PSMF1 missense and loss-of-function variants co-segregate with phenotypes from early-onset PD and parkinsonism to perinatal lethality with neurological manifestations across 15 unrelated pedigrees with 22 affected subjects, showing clear genotype-phenotype correlation. PSMF1 encodes the proteasome regulator PSMF1/PI31, a highly conserved, ubiquitously expressed partner of the 20S proteasome and neurodegeneration-associated F-box-O 7 and valosin-containing proteins. We demonstrate that PSMF1 variants impair mitochondrial membrane potential, dynamics and mitophagy in patient-derived fibroblasts. Additionally, we develop models of psmf1 knockdown Drosophila and Psmf1 conditional knockout mouse exhibiting age-dependent motor impairment, with diffuse gliosis in mice. These findings unequivocally link defective PSMF1 to early-onset PD and neurodegeneration and suggest mitochondrial dysfunction as a mechanistic contributor.

Low-dose BPA-induced neuronal energy metabolism dysfunction and apoptosis mediated by PINK1/parkin mitophagy pathway in juvenile rats

Bisphenol A (BPA) is related to neurological disorders involving mitochondrial dysfunction, while the mechanism remains elusive. Therefore, we explored it through in vitro and in vivo experiments. In vitro, hippocampal neurons derived from neonatal rats of different genders were exposed to 1-100 nM and 100 μM BPA, autophagy activator Rapa and inhibitor 3-MA for 7 d. The results suggested that even nanomolar BPA (1-100 nM) disturbed Ca2+ homeostasis and damaged the integrity of mitochondrial cristae in neurons (p < 0.05). Furthermore, BPA increased the number of autophagic lysosomes, LC3II/LC3I ratio, and p62 expression, and decreased parkin expression (p < 0.05), suggesting that the entry of damaged mitochondria into autophagic pathway was prompted, while the autophagic degradation pathway was blocked. This further disrupts neuronal energy metabolism and promotes neuronal apoptosis. However, Rapa attenuated the adverse effects caused by BPA, while 3-MA exacerbated these reactions. In vivo, exposure of juvenile rats to 0.5, 50, 5000 μg/kg‧bw/day BPA during PND 7-21 markedly impaired the structure of hippocampal mitochondria, increased the number of autophagosomes, the rate of neuronal apoptosis, and the expression levels of pro-apoptotic proteins Cyt C, Bax, Bak1, and Caspase3, and decreased the expression of anti-apoptotic protein Bcl2 (p < 0.05). Particularly, male rats are more sensitive to low-dose BPA than females. Overall, environmental-doses BPA can induce the imbalance of energy metabolism in hippocampal neurons via PINK1/parkin mitophagy, thereby inducing their apoptosis. Importantly, this study provides a theoretical basis for attenuating BPA-related neurological diseases.

Dopamine‑iron homeostasis interaction rescues mitochondrial fitness in Parkinson's disease

Imbalances of iron and dopamine metabolism along with mitochondrial dysfunction have been linked to the pathogenesis of Parkinson's disease (PD). We have previously suggested a direct link between iron homeostasis and dopamine metabolism, as dopamine can increase cellular uptake of iron into macrophages thereby promoting oxidative stress responses. In this study, we investigated the interplay between iron, dopamine, and mitochondrial activity in neuroblastoma SH-SY5Y cells and human induced pluripotent stem cell (hiPSC)-derived dopaminergic neurons differentiated from a healthy control and a PD patient with a mutation in the α-synuclein (SNCA) gene. In SH-SY5Y cells, dopamine treatment resulted in increased expression of the transmembrane iron transporters transferrin receptor 1 (TFR1), ferroportin (FPN), and mitoferrin2 (MFRN2) and intracellular iron accumulation, suggesting that dopamine may promote iron uptake. Furthermore, dopamine supplementation led to reduced mitochondrial fitness including decreased mitochondrial respiration, increased cytochrome c control efficiency, reduced mtDNA copy number and citrate synthase activity, increased oxidative stress and impaired aconitase activity. In dopaminergic neurons derived from a healthy control individual, dopamine showed comparable effects as observed in SH-SY5Y cells. The hiPSC-derived PD neurons harboring an endogenous SNCA mutation demonstrated altered mitochondrial iron homeostasis, reduced mitochondrial capacity along with increased oxidative stress and alterations of tricarboxylic acid cycle linked metabolic pathways compared with control neurons. Importantly, dopamine treatment of PD neurons promoted a rescue effect by increasing mitochondrial respiration, activating antioxidant stress response, and normalizing altered metabolite levels linked to mitochondrial function. These observations provide evidence that dopamine affects iron homeostasis, intracellular stress responses and mitochondrial function in healthy cells, while dopamine supplementation can restore the disturbed regulatory network in PD cells.

Spatially resolved multiomics on the neuronal effects induced by spaceflight in mice

Impairment of the central nervous system (CNS) poses a significant health risk for astronauts during long-duration space missions. In this study, we employed an innovative approach by integrating single-cell multiomics (transcriptomics and chromatin accessibility) with spatial transcriptomics to elucidate the impact of spaceflight on the mouse brain in female mice. Our comparative analysis between ground control and spaceflight-exposed animals revealed significant alterations in essential brain processes including neurogenesis, synaptogenesis and synaptic transmission, particularly affecting the cortex, hippocampus, striatum and neuroendocrine structures. Additionally, we observed astrocyte activation and signs of immune dysfunction. At the pathway level, some spaceflight-induced changes in the brain exhibit similarities with neurodegenerative disorders, marked by oxidative stress and protein misfolding. Our integrated spatial multiomics approach serves as a stepping stone towards understanding spaceflight-induced CNS impairments at the level of individual brain regions and cell types, and provides a basis for comparison in future spaceflight studies. For broader scientific impact, all datasets from this study are available through an interactive data portal, as well as the National Aeronautics and Space Administration (NASA) Open Science Data Repository (OSDR).

Targeting NKAα1 to treat Parkinson's disease through inhibition of mitophagy-dependent ferroptosis

Dysfunction of the Na+/K+-ATPase (NKA) has been documented in various neurodegenerative diseases, yet the specific role of NKAα1 in Parkinson's disease (PD) remains incompletely understood. In this investigation, we utilized NKAα1 haploinsufficiency (NKAα1+/-) mice to probe the influence of NKAα1 on dopaminergic (DA) neurodegeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Our findings reveal that NKAα1+/- mice displayed a heightened loss of DA neurons and more pronounced motor dysfunction compared to the control group when exposed to MPTP. Intriguingly, this phenomenon coincided with the activation of ferroptosis and impaired mitophagy both in vivo and in vitro. To scrutinize the role and underlying mechanism of NKAα1 in PD, we employed DR-Ab, an antibody targeting the DR-region of the NKA α subunit. Our study demonstrates that the administration of DR-Ab effectively reinstated the membrane abundance of NKAα1, thereby mitigating MPTP-induced DA neuron loss and subsequent improvement in behavioral deficit. Mechanistically, DR-Ab heightened the formation of the surface NKAα1/SLC7A11 complex, inhibiting SLC7A11-dependent ferroptosis. Moreover, DR-Ab disrupted the cytosolic interaction between NKAα1 and Parkin, facilitating the translocation of Parkin to mitochondria and enhancing the process of mitophagy. In conclusion, this study establishes NKAα1 as a key regulator of ferroptosis and mitophagy, identifying its DR-region as a promising therapeutic target for PD.

Toxic interactions between dopamine, α-synuclein, monoamine oxidase, and genes in mitochondria of Parkinson's disease

Parkinson's disease is characterized by its distinct pathological features; loss of dopamine neurons in the substantia nigra pars compacta and accumulation of Lewy bodies and Lewy neurites containing modified α-synuclein. Beneficial effects of L-DOPA and dopamine replacement therapy indicate dopamine deficit as one of the main pathogenic factors. Dopamine and its oxidation products are proposed to induce selective vulnerability in dopamine neurons. However, Parkinson's disease is now considered as a generalized disease with dysfunction of several neurotransmitter systems caused by multiple genetic and environmental factors. The pathogenic factors include oxidative stress, mitochondrial dysfunction, α-synuclein accumulation, programmed cell death, impaired proteolytic systems, neuroinflammation, and decline of neurotrophic factors. This paper presents interactions among dopamine, α-synuclein, monoamine oxidase, its inhibitors, and related genes in mitochondria. α-Synuclein inhibits dopamine synthesis and function. Vice versa, dopamine oxidation by monoamine oxidase produces toxic aldehydes, reactive oxygen species, and quinones, which modify α-synuclein, and promote its fibril production and accumulation in mitochondria. Excessive dopamine in experimental models modifies proteins in the mitochondrial electron transport chain and inhibits the function. α-Synuclein and familiar Parkinson's disease-related gene products modify the expression and activity of monoamine oxidase. Type A monoamine oxidase is associated with neuroprotection by an unspecific dose of inhibitors of type B monoamine oxidase, rasagiline and selegiline. Rasagiline and selegiline prevent α-synuclein fibrillization, modulate this toxic collaboration, and exert neuroprotection in experimental studies. Complex interactions between these pathogenic factors play a decisive role in neurodegeneration in PD and should be further defined to develop new therapies for Parkinson's disease.

Propionic acid affects the synaptic architecture of rat hippocampus and prefrontal cortex

It is well documented that propionic acid (PPA) produces behavioral, morphological, molecular and immune responses in rats that are characteristic of autism spectrum disorder in humans. However, whether PPA affects the ultrastructure and synaptic architecture of regions of autistic brain has not been adequately addressed. Earlier we show that single intraperitoneal (IP) injection of PPA (175 mg/kg) produces superficial changes in the spatial memory and learning of adolescent male Wistar rats. However, in neurons, synapses and glial cells of hippocampal CA1 area and medial prefrontal cortex transient (mainly) or enduring alterations were detected. In this study, we used electron microscopic morphometric analysis to test the effect of PPA on different structural parameters of axodendritic synapses of the hippocampus and prefrontal cortex. The animals were treated with a single IP injection of PPA (175 mg/kg). The length and width of synaptic active zone, the area of presynaptic and postsynaptic mitochondria, the distance between presynaptic mitochondria and the synapse active zone, the distance between postsynaptic mitochondria and postsynaptic density and the depth and opening diameter of neuronal porosome complex were evaluated. Our results show that synaptic mitochondria of the hippocampus and prefrontal cortex are the most vulnerable to PPA treatment: in both regions, the area of postsynaptic mitochondria were increased. In general, our results show that even small dose of PPA, which produces only superficial effects on spatial memory and learning is able to alter the synapse architecture in brain regions involved in cognition and autism pathogenesis. Therefore, the microbiome may be involved in the control of neurotransmission in these regions.

Mitochondria-Associated MicroRNAs and Parkinson's Disease

Parkinson's Disease (PD) occurs as a result of the progressive loss of dopaminergic neurons within the substantia nigra causing motor and non-motor symptoms and has become more prevalent within the last several decades. With mitochondria being essential to cellular survival, mitochondrial dysfunction contributes to the disease progression by increasing neuron loss through (1) insufficient ATP production and (2) reactive oxygen species generation. MicroRNAs (miRNAs) are small molecules located throughout cells that regulate gene expression, particularly mitochondrial function. Through their own dysregulation, miRNAs offset the delicate balance of mitochondrial function by altering or dysregulating the expression of proteins, increasing neuroinflammation, increasing retention of toxic substances, limiting the removal of reactive oxygen species, and preventing mitophagy. Improper mitochondrial function places cells at increased risk of apoptosis, a major concern in individuals with PD due to their reduced number of dopaminergic neurons. This article has identified the 17 most promising mitochondrial associated miRNAs within PD: hsa-miR-4639-5p, miR-376a, miR-205, miR-421, miR-34b/c, miR-150, miR-7, miR-132, miR-17-5p, miR-20a, miR-93, miR-106, miR-181, miR-193b, miR-128, miR-181a, and miR-124-3p. These miRNAs alter mitochondrial function and synaptic energy by impeding normal gene expression when up or downregulated. However, there is limited research regarding mitochondria-localized miRNAs that are typically seen in other diseases. Mitochondria-localized miRNA may have a greater impact on mitochondrial dysfunction due to their proximity. Further research is needed to determine the location of these miRNAs and to better understand their regulatory capabilities on mitochondrial and synaptic function within PD.

The Vital Role of Melatonin and Its Metabolites in the Neuroprotection and Retardation of Brain Aging

While primarily produced in the pineal gland, melatonin's influence goes beyond its well-known role in regulating sleep, nighttime metabolism, and circadian rhythms, in the field of chronobiology. A plethora of new data demonstrates melatonin to be a very powerful molecule, being a potent ROS/RNS scavenger with anti-inflammatory, immunoregulatory, and oncostatic properties. Melatonin and its metabolites exert multiple beneficial effects in cutaneous and systemic aging. This review is focused on the neuroprotective role of melatonin during aging. Melatonin has an anti-aging capacity, retarding the rate of healthy brain aging and the development of age-related neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, amyotrophic lateral sclerosis, etc. Melatonin, as well as its metabolites, N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) and N1-acetyl-5-methoxykynuramine (AMK), can reduce oxidative brain damage by shielding mitochondria from dysfunction during the aging process. Melatonin could also be implicated in the treatment of neurodegenerative conditions, by modifying their characteristic low-grade neuroinflammation. It can either prevent the initiation of inflammatory responses or attenuate the ongoing inflammation. Drawing on the current knowledge, this review discusses the potential benefits of melatonin supplementation in preventing and managing cognitive impairment and neurodegenerative diseases.

Multi-omics analysis identifies sex-specific hepatic protein-metabolite networks in yellow catfish (Pelteobagrus fulvidraco) exposed to chronic hypoxia

Hypoxia disrupts the endocrine system of teleosts. The liver plays important roles in the endocrine system, energy storage, and metabolic processes. The aim of this study was to investigate the sex-specific hepatic response of yellow catfish under chronic hypoxia at the multi-omics level. Common hepatic responses in both sexes included the HIF-1 signaling pathway, glycolysis/gluconeogenesis, and steroid biosynthesis. Hypoxia dysregulated primary bile acid biosynthesis, lipid metabolism, and vitellogenin levels in female fish. Endoplasmic reticulum function in females also tended to be disrupted by hypoxia, as evidenced by significantly enriched pathways, including ribosome, protein processing in the endoplasmic reticulum, and RNA degradation. Other pathways, including the TCA cycle, oxidative phosphorylation, and Parkinson's and Huntington's disease, were highly enriched by hypoxia in male fish, suggesting that mitochondrial function was dysregulated. In both sexes of yellow catfish, the cell cycle was arrested and apoptosis was inhibited under chronic hypoxia. Multi-omics suggested that SLC2A5, CD209, LGMN, and NEDD8 served as sex-specific markers in these fish under chronic hypoxia. Our results provide insights into hepatic adaptation to chronic hypoxia and facilitate our understanding of sex-specific responses in fish.

High-fat diet exacerbates 1-Bromopropane-induced loss of dopaminergic neurons in the substantia nigra of mice through mitochondrial damage associated necroptotic pathway

In recent years, accumulating evidence supports that occupational exposure to solvents is associated with an increased incidence of Parkinson's disease (PD) among workers. The neurotoxic effects of 1-bromopropane (1-BP), a widely used new-type solvent, are well-established, yet data on its relationship with the etiology of PD remain limited. Simultaneously, high-fat consumption in modern society is recognized as a significant risk factor for PD. However, whether there is a synergistic effect between a high-fat diet and 1-BP exposure remains unclear. In this study, adult C57BL/6 mice were fed either a chow or a high-fat diet for 18 weeks prior to 12-week 1-BP treatment. Subsequent neurobehavioral and neuropathological examinations were conducted to assess the effects of 1-BP exposure on parkinsonian pathology. The results demonstrated that 1-BP exposure produced obvious neurobehavioral abnormalities and dopaminergic degeneration in the nigral region of mice. Importantly, a high-fat diet further exacerbated the impact of 1-BP on motor and cognitive abnormalities in mice. Mechanistic investigation revealed that mitochondrial damage and mtDNA release induced by 1-BP and high-fat diet activate NLRP3 and cGAS-STING pathway- mediated neuroinflammatory response, and ultimately lead to necroptosis of dopaminergic neurons. In summary, our study unveils a potential link between chronic 1-BP exposure and PD-like pathology with motor and no-motor defects in experimental animals, and long-term high-fat diet can further promote 1-BP neurotoxicity, which underscores the pivotal role of environmental factors in the etiology of PD.

High-Performance Hydrogel-Encapsulated Engineered Exosomes for Supporting Endoplasmic Reticulum Homeostasis and Boosting Diabetic Bone Regeneration

The regeneration of bone defects in diabetic patients still faces challenges, as the intrinsic healing process is impaired by hyperglycemia. Inspired by the discovery that the endoplasmic reticulum (ER) is in a state of excessive stress and dysfunction under hyperglycemia, leading to osteogenic disorder, a novel engineered exosome is proposed to modulate ER homeostasis for restoring the function of mesenchymal stem cells (MSCs). The results indicate that the constructed engineered exosomes efficiently regulate ER homeostasis and dramatically facilitate the function of MSCs in the hyperglycemic niche. Additionally, the underlying therapeutic mechanism of exosomes is elucidated. The results reveal that exosomes can directly provide recipient cells with SHP2 for the activation of mitophagy and elimination of mtROS, which is the immediate cause of ER dysfunction. To maximize the therapeutic effect of engineered exosomes, a high-performance hydrogel with self-healing, bioadhesive, and exosome-conjugating properties is applied to encapsulate the engineered exosomes for in vivo application. In vivo, evaluation in diabetic bone defect repair models demonstrates that the engineered exosomes delivering hydrogel system intensively enhance osteogenesis. These findings provide crucial insight into the design and biological mechanism of ER homeostasis-based tissue-engineering strategies for diabetic bone regeneration.