Antisense therapy:a potential breakthrough in the treatment of neurodegenerative diseases

Neurodegenerative diseases are a group of disorders characterized by the progressive degeneration of neurons in the central or peripheral nervous system.Currently,there is no cure for neurodegenerative diseases and this means a heavy burden for patients and the health system worldwide.Therefore,it is necessary to find new therapeutic approaches,and antisense therapies offer this possibility,having the great advantage of not modifying cellular genome and potentially being safer.Many preclinical and clinical studies aim to test the safety and effectiveness of antisense therapies in the treatment of neurodegenerative diseases.The objective of this review is to summarize the recent advances in the development of these new technologies to treat the most common neurodegenerative diseases,with a focus on those antisense therapies that have already received the approval of the U.S.Food and Drug Administration.

The role of exosomes in adult neurogenesis:implications for neurodegenerative diseases

Exosomes are cup-shaped extracellular vesicles with a lipid bilayer that is approximately 30 to 200 nm in thickness.Exosomes are widely distributed in a range of body fluids,including urine,blood,milk,and saliva.Exosomes exert biological function by transporting factors between different cells and by regulating biological pathways in recipient cells.As an important form of intercellular communication,exosomes are increasingly being investigated due to their ability to transfer bioactive molecules such as lipids,proteins,mRNAs,and microRNAs between cells,and because they can regulate physiological and pathological processes in the central nervous system.Adult neurogenesis is a multistage process by which new neurons are generated and migrate to be integrated into existing neuronal circuits.In the adult brain,neurogenesis is mainly localized in two specialized niches:the subventricular zone adjacent to the lateral ventricles and the subgranular zone of the dentate gyrus.An increasing body of evidence indicates that adult neurogenesis is tightly controlled by environmental conditions with the niches.In recent studies,exosomes released from different sources of cells were shown to play an active role in regulating neurogenesis both in vitro and in vivo,thereby participating in the progression of neurodegenerative disorders in patients and in various disease models.Here,we provide a state-of-the-art synopsis of existing research that aimed to identify the diverse components of exosome cargoes and elucidate the therapeutic potential of exosomal contents in the regulation of neurogenesis in several neurodegenerative diseases.We emphasize that exosomal cargoes could serve as a potential biomarker to monitor functional neurogenesis in adults.In addition,exosomes can also be considered as a novel therapeutic approach to treat various neurodegenerative disorders by improving endogenous neurogenesis to mitigate neuronal loss in the central nervous system.

Total flavonoids of Astragalus membranaceus protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity in mice by inhibiting ferroptosis through SLC7A11/GPX-4 signaling pathway

Parkinson’s disease(PD)is a common neurodegenerative disorder with no cure.Astragalus membranaceus is used in Chinese culture as a food supplement to boost immunity.The present study aimed to explore the neuroprotective effects of total flavonoids extracted from A.membranaceus(TFA)and their protective mechanisms.TFA offered neuroprotection against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)in the mouse model of Parkinsonism,by improving behavior performance in the gait analysis and pole test,and inhibiting the decline of tyrosine hydroxylase(TH)positive neurons and TH protein expression in substantia nigra of mice.TFA also prevented 1-methyl-4-phenylpyridinium(MPP+)induced neurotoxicity in SHSY5Y cells,by increasing GSH and GSH/GSSG ratio,and reducing reactive oxygen species.In addition,the neuroprotective effects of TFA were associated with its ability to restore MPTP/MPP+induced downregulation of SLC7A11 and glutathione peroxidase 4(GPX-4).In conclusion,we demonstrated that TFA exerted significant neuroprotection against MPTP/MPP+induced neurodegeneration by inhibiting ferroptosis through the regulation of SLC7A11/GPX-4 axis,suggesting the use of TFA as a possible food supplement in the prevention of PD.

Interplay between the glymphatic system and neurotoxic proteins in Parkinson’s disease and related disorders:current knowledge and future directions

Parkinson’s disease is a common neurodegenerative disorder that is associated with abnormal aggregation and accumulation of neurotoxic proteins,includingα-synuclein,amyloid-β,and tau,in addition to the impaired elimination of these neurotoxic protein.Atypical parkinsonism,which has the same clinical presentation and neuropathology as Parkinson’s disease,expands the disease landscape within the continuum of Parkinson’s disease and related disorders.The glymphatic system is a waste clearance system in the brain,which is responsible for eliminating the neurotoxic proteins from the interstitial fluid.Impairment of the glymphatic system has been proposed as a significant contributor to the development and progression of neurodegenerative disease,as it exacerbates the aggregation of neurotoxic proteins and deteriorates neuronal damage.Therefore,impairment of the glymphatic system could be considered as the final common pathway to neurodegeneration.Previous evidence has provided initial insights into the potential effect of the impaired glymphatic system on Parkinson’s disease and related disorders;however,many unanswered questions remain.This review aims to provide a comprehensive summary of the growing literature on the glymphatic system in Parkinson’s disease and related disorders.The focus of this review is on identifying the manifestations and mechanisms of interplay between the glymphatic system and neurotoxic proteins,including loss of polarization of aquaporin-4 in astrocytic endfeet,sleep and circadian rhythms,neuroinflammation,astrogliosis,and gliosis.This review further delves into the underlying pathophysiology of the glymphatic system in Parkinson’s disease and related disorders,and the potential implications of targeting the glymphatic system as a novel and promising therapeutic strategy.

Recent progress in the applications of presynaptic dopaminergic positron emission tomography imaging in parkinsonism

Nowadays,presynaptic dopaminergic positron emission tomography,which assesses deficiencies in dopamine synthesis,storage,and transport,is widely utilized for early diagnosis and differential diagnosis of parkinsonism.This review provides a comprehensive summary of the latest developments in the application of presynaptic dopaminergic positron emission tomography imaging in disorders that manifest parkinsonism.We conducted a thorough literature search using reputable databases such as PubMed and Web of Science.Selection criteria involved identifying peer-reviewed articles published within the last 5 years,with emphasis on their relevance to clinical applications.The findings from these studies highlight that presynaptic dopaminergic positron emission tomography has demonstrated potential not only in diagnosing and differentiating various Parkinsonian conditions but also in assessing disease severity and predicting prognosis.Moreover,when employed in conjunction with other imaging modalities and advanced analytical methods,presynaptic dopaminergic positron emission tomography has been validated as a reliable in vivo biomarker.This validation extends to screening and exploring potential neuropathological mechanisms associated with dopaminergic depletion.In summary,the insights gained from interpreting these studies are crucial for enhancing the effectiveness of preclinical investigations and clinical trials,ultimately advancing toward the goals of neuroregeneration in parkinsonian disorders.

Roles of neuronal lysosomes in the etiology of Parkinson’s disease

Therapeutic progress in neurodegenerative conditions such as Parkinson’s disease has been hampered by a lack of detailed knowledge of its molecular etiology.The advancements in genetics and genomics have provided fundamental insights into specific protein players and the cellular processes involved in the onset of disease.In this respect,the autophagy-lysosome system has emerged in recent years as a strong point of convergence for genetics,genomics,and pathologic indications,spanning both familial and idiopathic Parkinson’s disease.Most,if not all,genes linked to familial disease are involved,in a regulatory capacity,in lysosome function(e.g.,LRRK2,alpha-synuclein,VPS35,Parkin,and PINK1).Moreover,the majority of genomic loci associated with increased risk of idiopathic Parkinson’s cluster in lysosome biology and regulation(GBA as the prime example).Lastly,neuropathologic evidence showed alterations in lysosome markers in autoptic material that,coupled to the alpha-synuclein proteinopathy that defines the disease,strongly indicate an alteration in functionality.In this Brief Review article,I present a personal perspective on the molecular and cellular involvement of lysosome biology in Parkinson’s pathogenesis,aiming at a larger vision on the events underlying the onset of the disease.The attempts at targeting autophagy for therapeutic purposes in Parkinson’s have been mostly aimed at“indiscriminately”enhancing its activity to promote the degradation and elimination of aggregate protein accumulations,such as alpha-synuclein Lewy bodies.However,this approach is based on the assumption that protein pathology is the root cause of disease,while pre-pathology and pre-degeneration dysfunctions have been largely observed in clinical and pre-clinical settings.In addition,it has been reported that unspecific boosting of autophagy can be detrimental.Thus,it is important to understand the mechanisms of specific autophagy forms and,even more,the adjustment of specific lysosome functionalities.Indeed,lysosomes exert fine signaling capacities in addition to their catabolic roles and might participate in the regulation of neuronal and glial cell functions.Here,I discuss hypotheses on these possible mechanisms,their links with etiologic and risk factors for Parkinson’s disease,and how they could be targeted for disease-modifying purposes.

Cath-KP,a novel peptide derived from frog skin,prevents oxidative stress damage in a Parkinson’s disease model

Parkinson’s disease(PD)is a neurodegenerative condition that results in dyskinesia,with oxidative stress playing a pivotal role in its progression.Antioxidant peptides may thus present therapeutic potential for PD.In this study,a novel cathelicidin peptide(Cath-KP;GCSGRFCNLF NNRRPGRLTLIHRPGGDKRTSTGLIYV)was identified from the skin of the Asiatic painted frog(Kaloula pulchra).Structural analysis using circular dichroism and homology modeling revealed a uniqueαββconformation for Cath-KP.In vitro experiments,including free radical scavenging and ferric-reducing antioxidant analyses,confirmed its antioxidant properties.Using the 1-methyl-4-phenylpyridinium ion(MPP^(+))-induced dopamine cell line and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced PD mice,Cath-KP was found to penetrate cells and reach deep brain tissues,resulting in improved MPP^(+)-induced cell viability and reduced oxidative stress-induced damage by promoting antioxidant enzyme expression and alleviating mitochondrial and intracellular reactive oxygen species accumulation through Sirtuin-1(Sirt1)/Nuclear factor erythroid 2-related factor 2(Nrf2)pathway activation.Both focal adhesion kinase(FAK)and p38 were also identified as regulatory elements.In the MPTP-induced PD mice,Cath-KP administration increased the number of tyrosine hydroxylase(TH)-positive neurons,restored TH content,and ameliorated dyskinesia.To the best of our knowledge,this study is the first to report on a cathelicidin peptide demonstrating potent antioxidant and neuroprotective properties in a PD model by targeting oxidative stress.These findings expand the known functions of cathelicidins,and hold promise for the development of therapeutic agents for PD.

Olfactory dysfunction and its related molecular mechanisms in Parkinson’s disease

Changes in olfactory function are considered to be early biomarkers of Parkinson’s disease.Olfactory dysfunction is one of the earliest non-motor features of Parkinson’s disease,appearing in about 90%of patients with early-stage Parkinson’s disease,and can often predate the diagnosis by years.Therefore,olfactory dysfunction should be considered a reliable marker of the disease.However,the mechanisms responsible for olfactory dysfunction are currently unknown.In this article,we clearly explain the pathology and medical definition of olfactory function as a biomarker for early-stage Parkinson’s disease.On the basis of the findings of clinical olfactory function tests and animal model experiments as well as neurotransmitter expression levels,we further characterize the relationship between olfactory dysfunction and neurodegenerative diseases as well as the molecular mechanisms underlying olfactory dysfunction in the pathology of early-stage Parkinson’s disease.The findings highlighted in this review suggest that olfactory dysfunction is an important biomarker for preclinical-stage Parkinson’s disease.Therefore,therapeutic drugs targeting non-motor symptoms such as olfactory dysfunction in the early stage of Parkinson’s disease may prevent or delay dopaminergic neurodegeneration and reduce motor symptoms,highlighting the potential of identifying effective targets for treating Parkinson’s disease by inhibiting the deterioration of olfactory dysfunction.

Emerging role of galectin 3 in neuroinflammation and neurodegeneration

Neuroinflammation and neurodegeneration are key processes that mediate the development and progression of neurological diseases.However,the mechanisms modulating these processes in different diseases remain incompletely understood.Advances in single cell based multi-omic analyses have helped to identify distinct molecular signatures such as Lgals3 that is associated with neuroinflammation and neurodegeneration in the central nervous system(CNS).Lgals3 encodes galectin-3(Gal3),aβ-galactoside and glycan binding glycoprotein that is frequently upregulated by reactive microglia/macrophages in the CNS during various neurological diseases.While Gal3 has previously been associated with non-CNS inflammatory and fibrotic diseases,recent studies highlight Gal3 as a prominent regulator of inflammation and neuroaxonal damage in the CNS during diseases such as multiple sclerosis,Alzheimer’s disease,and Parkinson’s disease.In this review,we summarize the pleiotropic functions of Gal3 and discuss evidence that demonstrates its detrimental role in neuroinflammation and neurodegeneration during different neurological diseases.We also consider the challenges of translating preclinical observations into targeting Gal3 in the human CNS.

The autophagy protein Atg9 functions in glia and contributes to parkinsonian symptoms in a Drosophila model of Parkinson’s disease

Parkinson’s disease is a progressive neurodegenerative disease characterized by motor deficits,dopaminergic neuron loss,and brain accumulation ofα-synuclein aggregates called Lewy bodies.Dysfunction in protein degradation pathways,such as autophagy,has been demonstrated in neurons as a critical mechanism for eliminating protein aggregates in Parkinson’s disease.However,it is less well understood how protein aggregates are eliminated in glia,the other cell type in the brain.In the present study,we show that autophagy-related gene 9(Atg9),the only transmembrane protein in the autophagy machinery,is highly expressed in Drosophila glia from adult brain.Results from immunostaining and live cell imaging analysis reveal that a portion of Atg9 localizes to the trans-Golgi network,autophagosomes,and lysosomes in glia.Atg9 is persistently in contact with these organelles.Lacking glial atg9 reduces the number of omegasomes and autophagosomes,and impairs autophagic substrate degradation.This suggests that glial Atg9 participates in the early steps of autophagy,and hence the control of autophagic degradation.Importantly,loss of glial atg9 induces parkinsonian symptoms in Drosophila including progressive loss of dopaminergic neurons,locomotion deficits,and glial activation.Our findings identify a functional role of Atg9 in glial autophagy and establish a potential link between glial autophagy and Parkinson’s disease.These results may provide new insights on the underlying mechanism of Parkinson’s disease.

Effects of mesenchymal stem cell on dopaminergic neurons,motor and memory functions in animal models of Parkinson's disease:a systematic review and meta-analysis

Parkinson’s disease is chara cterized by the loss of dopaminergic neurons in the substantia nigra pars com pacta,and although restoring striatal dopamine levels may improve symptoms,no treatment can cure or reve rse the disease itself.Stem cell therapy has a regenerative effect and is being actively studied as a candidate for the treatment of Parkinson’s disease.Mesenchymal stem cells are considered a promising option due to fewer ethical concerns,a lower risk of immune rejection,and a lower risk of teratogenicity.We performed a meta-analysis to evaluate the therapeutic effects of mesenchymal stem cells and their derivatives on motor function,memory,and preservation of dopamine rgic neurons in a Parkinson’s disease animal model.We searched bibliographic databases(PubMed/MEDLINE,Embase,CENTRAL,Scopus,and Web of Science)to identify articles and included only pee r-reviewed in vivo interve ntional animal studies published in any language through J une 28,2023.The study utilized the random-effect model to estimate the 95%confidence intervals(CI)of the standard mean differences(SMD)between the treatment and control groups.We use the systematic review center for laboratory animal expe rimentation’s risk of bias tool and the collaborative approach to meta-analysis and review of animal studies checklist for study quality assessment.A total of 33studies with data from 840 Parkinson’s disease model animals were included in the meta-analysis.Treatment with mesenchymal stem cells significantly improved motor function as assessed by the amphetamine-induced rotational test.Among the stem cell types,the bone marrow MSCs with neurotrophic factor group showed la rgest effect size(SMD[95%CI]=-6.21[-9.50 to-2.93],P=0.0001,I^(2)=0.0%).The stem cell treatment group had significantly more tyrosine hydroxylase positive dopamine rgic neurons in the striatum([95%CI]=1.04[0.59 to 1.49],P=0.0001,I^(2)=65.1%)and substantia nigra(SMD[95%CI]=1.38[0.89 to 1.87],P=0.0001,I^(2)=75.3%),indicating a protective effect on dopaminergic neurons.Subgroup analysis of the amphetamine-induced rotation test showed a significant reduction only in the intracranial-striatum route(SMD[95%CI]=-2.59[-3.25 to-1.94],P=0.0001,I^(2)=74.4%).The memory test showed significant improvement only in the intravenous route(SMD[95%CI]=4.80[1.84 to 7.76],P=0.027,I^(2)=79.6%).Mesenchymal stem cells have been shown to positively impact motor function and memory function and protect dopaminergic neurons in preclinical models of Parkinson’s disease.Further research is required to determine the optimal stem cell types,modifications,transplanted cell numbe rs,and delivery methods for these protocols.

Relationship among Parkinson’s disease, constipation, microbes, and microbiological therapy

This comprehensive review elucidates the complex interplay between gut microbiota and constipation in Parkinson’s disease(PD),a prevalent non-motor symptom contributing significantly to patients’morbidity.A marked alteration in the gut microbiota,predominantly an increase in the abundance of Proteobacteria and Bacteroidetes,is observed in PD-related constipation.Conventional treatments,although safe,have failed to effectively alleviate symptoms,thereby necessitating the development of novel therapeutic strategies.Microbiological interventions such as prebiotics,probiotics,and fecal microbiota transplantation(FMT)hold therapeutic potential.While prebiotics improve bowel movements,probiotics are effective in enhancing stool consistency and alleviating abdominal discomfort.FMT shows potential for significantly alleviating constipation symptoms by restoring gut microbiota balance in patients with PD.Despite promising developments,the causal relationship between changes in gut microbiota and PD-related constipation remains elusive,highlighting the need for further research in this expanding field.

The autophagy-lysosome pathway:a potential target in the chemical and gene therapeutic strategies for Parkinson’s disease

Parkinson’s disease is a common neurodegenerative disease with movement disorders associated with the intracytoplasmic deposition of aggregate proteins such asα-synuclein in neurons.As one of the major intracellular degradation pathways,the autophagy-lysosome pathway plays an important role in eliminating these proteins.Accumulating evidence has shown that upregulation of the autophagy-lysosome pathway may contribute to the clearance ofα-synuclein aggregates and protect against degeneration of dopaminergic neurons in Parkinson’s disease.Moreover,multiple genes associated with the pathogenesis of Parkinson’s disease are intimately linked to alterations in the autophagy-lysosome pathway.Thus,this pathway appears to be a promising therapeutic target for treatment of Parkinson’s disease.In this review,we briefly introduce the machinery of autophagy.Then,we provide a description of the effects of Parkinson’s disease–related genes on the autophagy-lysosome pathway.Finally,we highlight the potential chemical and genetic therapeutic strategies targeting the autophagy–lysosome pathway and their applications in Parkinson’s disease.

A review of the neurotransmitter system associated with cognitive function of the cerebellum in Parkinson's disease

The dichotomized brain system is a concept that was generalized from the‘dual syndrome hypothesis’to explain the heterogeneity of cognitive impairment,in which anterior and posterior brain systems are independent but partially overlap.The dopaminergic system acts on the anterior brain and is responsible for executive function,working memory,and planning.In contrast,the cholinergic system acts on the posterior brain and is responsible for semantic fluency and visuospatial function.Evidence from dopaminergic/cholinergic imaging or functional neuroimaging has shed significant insight relating to the involvement of the cerebellum in the cognitive process of patients with Parkinson’s disease.Previous research has reported evidence that the cerebellum receives both dopaminergic and cholinergic projections.However,whether these two neurotransmitter systems are associated with cognitive function has yet to be fully elucidated.Furthermore,the precise role of the cerebellum in patients with Parkinson’s disease and cognitive impairment remains unclear.Therefore,in this review,we summarize the cerebellar dopaminergic and cholinergic projections and their relationships with cognition,as reported by previous studies,and investigated the role of the cerebellum in patients with Parkinson’s disease and cognitive impairment,as determined by functional neuroimaging.Our findings will help us to understand the role of the cerebellum in the mechanisms underlying cognitive impairment in Parkinson’s disease.

Physiological and pathological functions of circular RNAs in the nervous system

Circular RNAs(circRNAs)are a class of covalently closed single-stranded RNAs that are expressed during the development of specific cells and tissues.CircRNAs play crucial roles in physiological and pathological processes by sponging microRNAs,modulating gene transcription,controlling the activity of certain RNA-binding proteins,and producing functional peptides.A key focus of research at present is the functionality of circRNAs in the nervous system and several advances have emerged over the last 2 years.However,the precise role of circRNAs in the nervous system has yet to be comprehensively reviewed.In this review,we first summarize the recently described roles of circRNAs in brain development,maturity,and aging.Then,we focus on the involvement of circRNAs in various diseases of the central nervous system,such as brain cancer,chronic neurodegenerative diseases,acute injuries of the nervous system,and neuropathic pain.A better understanding of the functionality of circRNAs will help us to develop potential diagnostic,prognostic,and therapeutic strategies to treat diseases of the nervous system.

Mitophagy in neurodegenerative disease pathogenesis

Mitochondria are critical cellular energy resources and are central to the life of the neuron.Mitophagy selectively clears damaged or dysfunctional mitochondria through autophagic machinery to maintain mitochondrial quality control and homeostasis.Mature neurons are postmitotic and consume substantial energy,thus require highly efficient mitophagy pathways to turn over damaged or dysfunctional mitochondria.Recent evidence indicates that mitophagy is pivotal to the pathogenesis of neurological diseases.However,more work is needed to study mitophagy pathway components as potential therapeutic targets.In this review,we briefly discuss the characteristics of nonselective autophagy and selective autophagy,including ERphagy,aggrephagy,and mitophagy.We then introduce the mechanisms of Parkin-dependent and Parkin-independent mitophagy pathways under physiological conditions.Next,we summarize the diverse repertoire of mitochondrial membrane receptors and phospholipids that mediate mitophagy.Importantly,we review the critical role of mitophagy in the pathogenesis of neurodegenerative diseases including Alzheimer’s disease,Parkinson’s disease,and amyotrophic lateral sclerosis.Last,we discuss recent studies considering mitophagy as a potential therapeutic target for treating neurodegenerative diseases.Together,our review may provide novel views to better understand the roles of mitophagy in neurodegenerative disease pathogenesis.

Additive neurorestorative effects of exercise and docosahexaenoic acid intake in a mouse model of Parkinson’s disease

There is a need to develop interventions to slow or reverse the degeneration of dopamine neurons in Parkinson’s disease after diagnosis.Given that preclinical and clinical studies suggest benefits of dietary n-3 polyunsaturated fatty acids,such as docosahexaenoic acid,and exercise in Parkinson’s disease,we investigated whether both could synergistically interact to induce recovery of the dopaminergic pathway.First,mice received a unilateral stereotactic injection of 6-hydroxydopamine into the striatum to establish an animal model of nigrostriatal denervation.Four weeks after lesion,animals were fed a docosahexaenoic acid-enriched or a control diet for the next 8 weeks.During this period,the animals had access to a running wheel,which they could use or not.Docosahexaenoic acid treatment,voluntary exercise,or the combination of both had no effect on(i)distance traveled in the open field test,(ii)the percentage of contraversive rotations in the apomorphine-induction test or(iii)the number of tyrosine-hydroxylase-positive cells in the substantia nigra pars compacta.However,the docosahexaenoic acid diet increased the number of tyrosine-hydroxylase-positive terminals and induced a rise in dopamine concentrations in the lesioned striatum.Compared to docosahexaenoic acid treatment or exercise alone,the combination of docosahexaenoic acid and exercise(i)improved forelimb balance in the stepping test,(ii)decreased the striatal DOPAC/dopamine ratio and(iii)led to increased dopamine transporter levels in the lesioned striatum.The present results suggest that the combination of exercise and docosahexaenoic acid may act synergistically in the striatum of mice with a unilateral lesion of the dopaminergic system and provide support for clinical trials combining nutrition and physical exercise in the treatment of Parkinson’s disease.

α-Synuclein pathology from the body to the brain:so many seeds so close to the central soil

α-Synuclein is a protein that mainly exists in the presynaptic terminals.Abnormal folding and accumulation of α-synuclein are found in several neurodegenerative diseases,including Parkinson’s disease.Aggregated and highly phospho rylated a-synuclein constitutes the main component of Lewy bodies in the brain,the pathological hallmark of Parkinson s disease.For decades,much attention has been focused on the accumulation of α-synuclein in the brain parenchyma rather than considering Parkinson s disease as a systemic disease.Recent evidence demonstrates that,at least in some patients,the initial α-synuclein pathology originates in the peripheral organs and spreads to the brain.Injection of α-synuclein preformed fibrils into the gastrointestinal tra ct trigge rs the gutto-brain propagation of α-synuclein pathology.However,whether α-synuclein pathology can occur spontaneously in peripheral organs independent of exogenous α-synuclein preformed fibrils or pathological α-synuclein leakage from the central nervous system remains under investigation.In this review,we aimed to summarize the role of peripheral α-synuclein pathology in the pathogenesis of Parkinson’s disease.We also discuss the pathways by which α-synuclein pathology spreads from the body to the brain.

Multisensory mechanisms of gait and balance in Parkinson’s disease:an integrative review

Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have on our aging population.Posture and gait control does not happen automatically,as previously believed,but rather requires continuous involvement of central nervous mechanisms.To effectively exert control over the body,the brain must integrate multiple streams of sensory information,including visual,vestibular,and somatosensory signals.The mechanisms which underpin the integration of these multisensory signals are the principal topic of the present work.Existing multisensory integration theories focus on how failure of cognitive processes thought to be involved in multisensory integration leads to falls in older adults.Insufficient emphasis,however,has been placed on specific contributions of individual sensory modalities to multisensory integration processes and cross-modal interactions that occur between the sensory modalities in relation to gait and balance.In the present work,we review the contributions of somatosensory,visual,and vestibular modalities,along with their multisensory intersections to gait and balance in older adults and patients with Parkinson’s disease.We also review evidence of vestibular contributions to multisensory temporal binding windows,previously shown to be highly pertinent to fall risk in older adults.Lastly,we relate multisensory vestibular mechanisms to potential neural substrates,both at the level of neurobiology(concerning positron emission tomography imaging)and at the level of electrophysiology(concerning electroencephalography).We hope that this integrative review,drawing influence across multiple subdisciplines of neuroscience,paves the way for novel research directions and therapeutic neuromodulatory approaches,to improve the lives of older adults and patients with neurodegenerative diseases.

Cell reprogramming therapy for Parkinson’s disease

Parkinson’s disease is typically characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta.Many studies have been performed based on the supplementation of lost dopaminergic neurons to treat Parkinson’s disease.The initial strategy for cell replacement therapy used human fetal ventral midbrain and human embryonic stem cells to treat Parkinson’s disease,which could substantially alleviate the symptoms of Parkinson’s disease in clinical practice.However,ethical issues and tumor formation were limitations of its clinical application.Induced pluripotent stem cells can be acquired without sacrificing human embryos,which eliminates the huge ethical barriers of human stem cell therapy.Another widely considered neuronal regeneration strategy is to directly reprogram fibroblasts and astrocytes into neurons,without the need for intermediate proliferation states,thus avoiding issues of immune rejection and tumor formation.Both induced pluripotent stem cells and direct reprogramming of lineage cells have shown promising results in the treatment of Parkinson’s disease.However,there are also ethical concerns and the risk of tumor formation that need to be addressed.This review highlights the current application status of cell reprogramming in the treatment of Parkinson’s disease,focusing on the use of induced pluripotent stem cells in cell replacement therapy,including preclinical animal models and progress in clinical research.The review also discusses the advancements in direct reprogramming of lineage cells in the treatment of Parkinson’s disease,as well as the controversy surrounding in vivo reprogramming.These findings suggest that cell reprogramming may hold great promise as a potential strategy for treating Parkinson’s disease.