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1.
J Parkinsons Dis ; 2021 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-34744054

RESUMO

A recent breakthrough paper published in Science Translational Medicine has provided compelling evidence that inhibition of Parkin Interacting Substrate (PARIS) may offer clinical researchers an important new therapeutic approach since it shows considerable promise as an important biological target potentially capable of pharmaceutical intervention to slow long term neurodegeneration in patients with Parkinson's disease (PD). We present several PD-relevant perspectives on this paper that were not discussed in that otherwise entirely scientific narrative. We also outline the some of the work leading up to it, including the massive drug screen that proved necessary to discover a clinically suitable inhibitor of PARIS (Farnesol), as well as relevant PD research within the wider drug class, issues surrounding its future formulation, and next steps in translating this new knowledge into the clinic to evaluate possible long-term PD patient benefits.

2.
Sci Rep ; 11(1): 21500, 2021 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-34728675

RESUMO

The transcriptional repressor called parkin interacting substrate (PARIS; ZNF746) was initially identified as a novel co-substrate of parkin and PINK1 that leads to Parkinson's disease (PD) by disrupting mitochondrial biogenesis through peroxisome proliferator-activated receptor gamma (PPARγ) coactivator -1α (PGC-1α) suppression. Since its initial discovery, growing evidence has linked PARIS to defective mitochondrial biogenesis observed in PD pathogenesis. Yet, dopaminergic (DA) neuron-specific mechanistic underpinnings and genome-wide PARIS binding landscape has not been explored. We employed conditional translating ribosome affinity purification (TRAP) followed by RNA sequencing (TRAP-seq) for transcriptome profiling of DA neurons in transgenic Drosophila lines expressing human PARIS wild type (WT) or mutant (C571A). We also generated genome-wide maps of PARIS occupancy using ChIP-seq in human SH-SY5Y cells. The results demonstrated that PPARγ functions as a master regulator of PARIS-induced molecular changes at the transcriptome level, confirming that PARIS acts primarily on PGC-1α to lead to neurodegeneration in PD. Moreover, we identified that PARIS actively modulates expression of PPARγ target genes by physically binding to the promoter regions. Together, our work revealed how PARIS drives adverse effects on modulation of PPAR-γ associated gene clusters in DA neurons.

3.
eNeuro ; 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34759048

RESUMO

The G2019S mutation in leucine-rich repeat kinase 2 (LRRK2) causes familial Parkinson's disease (PD) and is also found in a subset of idiopathic cases. Prior studies in Drosophila and human induced pluripotent stem cell (iPSC)-derived dopamine neurons uncovered a pronounced effect of G2019S LRRK2 on mRNA translation. It was previously reported that G2019S LRRK2 promotes translation of mRNAs with complex 5' untranslated region (UTR) secondary structure, resulting in increased expression of calcium channels and dysregulated calcium homeostasis in human dopamine neurons. Here, we show that dysregulated translation occurs in the brains of mammalian LRRK2 models in vivo Through ribosome profiling studies of global translation, we observe that mRNAs with complex 5'UTR structure are also preferentially translated in the G2019S LRRK2-expressing mouse brain. Reporter assays suggest that this 5'UTR preference is independent of translation initiation factors. Conversely, translation of mRNAs with complex 5'UTR secondary structure is downregulated in LRRK2 knock-out (KO) mouse brain, indicating a robust link between LRRK2 kinase activity and translation of mRNA with complex 5'UTR structure. Further, substantia nigra pars compacta (SNpc) dopamine neurons in the G2019S LRRK2-expressing brain exhibit increased calcium influx, which is consistent with the previous report from human dopamine neurons. These results collectively suggest that LRRK2 plays a mechanistic role in translational regulation, and the G2019S mutation in LRRK2 causes translational defects leading to calcium dysregulation in the mammalian brain.Significance StatementParkinson's disease (PD)-linked G2019S mutation of leucine-rich repeat kinase 2 (LRRK2) is known to cause abnormalities in mRNA translation. These translational defects were suggested to cause calcium dysregulation, thereby imposing a long-term cellular stress to dopamine neurons. While these effects of G2019S LRRK2 on mRNA translation have been seen in Drosophila brain tissues and cultured mammalian neurons, translational profiling of the mammalian brain expressing G2019S LRRK2 has not been reported. In this study, we employed ribosome profiling to survey mRNA translation in the brains of LRRK2 mouse models, thereby demonstrating that the G2019S LRRK2 mutation broadly alters mRNA translation in the mouse brain.

4.
Neuron ; 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34644545

RESUMO

Impairment in glucocerebrosidase (GCase) is strongly associated with the development of Parkinson's disease (PD), yet the regulators responsible for its impairment remain elusive. In this paper, we identify the E3 ligase Thyroid Hormone Receptor Interacting Protein 12 (TRIP12) as a key regulator of GCase. TRIP12 interacts with and ubiquitinates GCase at lysine 293 to control its degradation via ubiquitin proteasomal degradation. Ubiquitinated GCase by TRIP12 leads to its functional impairment through premature degradation and subsequent accumulation of α-synuclein. TRIP12 overexpression causes mitochondrial dysfunction, which is ameliorated by GCase overexpression. Further, conditional TRIP12 knockout in vitro and knockdown in vivo promotes the expression of GCase, which blocks α-synuclein preformed fibrils (α-syn PFFs)-provoked dopaminergic neurodegeneration. Moreover, TRIP12 accumulates in human PD brain and α-synuclein-based mouse models. The identification of TRIP12 as a regulator of GCase provides a new perspective on the molecular mechanisms underlying dysfunctional GCase-driven neurodegeneration in PD.

5.
Pharmacol Rev ; 73(4): 33-97, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34663684

RESUMO

Parkinson disease (PD) used to be considered a nongenetic condition. However, the identification of several autosomal dominant and recessive mutations linked to monogenic PD has changed this view. Clinically manifest PD is then thought to occur through a complex interplay between genetic mutations, many of which have incomplete penetrance, and environmental factors, both neuroprotective and increasing susceptibility, which variably interact to reach a threshold over which PD becomes clinically manifested. Functional studies of PD gene products have identified many cellular and molecular pathways, providing crucial insights into the nature and causes of PD. PD originates from multiple causes and a range of pathogenic processes at play, ultimately culminating in nigral dopaminergic loss and motor dysfunction. An in-depth understanding of these complex and possibly convergent pathways will pave the way for therapeutic approaches to alleviate the disease symptoms and neuroprotective strategies to prevent disease manifestations. This review is aimed at providing a comprehensive understanding of advances made in PD research based on leveraging genetic insights into the pathogenesis of PD. It further discusses novel perspectives to facilitate identification of critical molecular pathways that are central to neurodegeneration that hold the potential to develop neuroprotective and/or neurorestorative therapeutic strategies for PD. SIGNIFICANCE STATEMENT: A comprehensive review of PD pathophysiology is provided on the complex interplay of genetic and environmental factors and biologic processes that contribute to PD pathogenesis. This knowledge identifies new targets that could be leveraged into disease-modifying therapies to prevent or slow neurodegeneration in PD.

6.
Nucleic Acids Res ; 49(19): 11083-11102, 2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34614178

RESUMO

Mutual crosstalk among poly(ADP-ribose) (PAR), activated PAR polymerase 1 (PARP1) metabolites, and DNA repair machinery has emerged as a key regulatory mechanism of the DNA damage response (DDR). However, there is no conclusive evidence of how PAR precisely controls DDR. Herein, six deubiquitinating enzymes (DUBs) associated with PAR-coupled DDR were identified, and the role of USP39, an inactive DUB involved in spliceosome assembly, was characterized. USP39 rapidly localizes to DNA lesions in a PAR-dependent manner, where it regulates non-homologous end-joining (NHEJ) via a tripartite RG motif located in the N-terminus comprising 46 amino acids (N46). Furthermore, USP39 acts as a molecular trigger for liquid demixing in a PAR-coupled N46-dependent manner, thereby directly interacting with the XRCC4/LIG4 complex during NHEJ. In parallel, the USP39-associated spliceosome complex controls homologous recombination repair in a PAR-independent manner. These findings provide mechanistic insights into how PAR chains precisely control DNA repair processes in the DDR.

7.
Parkinsonism Relat Disord ; 90: 134-141, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34561166

RESUMO

OBJECTIVE: Disease modification in Parkinson disease (PD) has remained an elusive goal, in spite of large investments over several decades. Following a large meeting of experts, this review article discusses the state of the science, possible reasons for past PD trials' failures to demonstrate disease-modifying benefit, and potential solutions. METHODS: The National Institute of Neurological Disorders and Stroke (NINDS) convened a meeting including leaders in the field and representatives of key stakeholder groups to discuss drug therapy with the goal of disease modification in PD. RESULTS: Important lessons can be learned from previous attempts, as well as from other fields. The selection process for therapeutic targets and agents differs among various organizations committed to therapeutic development. The areas identified as critical to target in future research include the development of relevant biomarkers, refinements of the targeted patient populations, considerations of novel trial designs, and improving collaborations between all stakeholders. CONCLUSIONS: We identify potential barriers to progress in disease modification for Parkinson's and propose a set of research priorities that may improve the likelihood of success.

8.
Brain ; 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34581802

RESUMO

Aberrant activation of the non-receptor kinase c-Abl is implicated in the development of pathogenic hallmarks of Parkinson's disease, such as α-synuclein aggregation and progressive neuronal loss. c-Abl-mediated phosphorylation and inhibition of parkin ligase function lead to accumulation of parkin-interacting substrate that mediates α-synuclein pathology-initiated dopaminergic neurodegeneration. Here we show that, in addition to parkin interacting substrate accumulation, c-Abl phosphorylation of parkin interacting substrate is required for parkin interacting substrate-induced cytotoxicity. c-Abl-mediated phosphorylation of parkin interacting substrate at Y137 (within the Krüeppel-associated box domain) drives its association with KAP1 and the repression of genes with diverse functions in pathways such as chromatin remodeling and p53-dependent cell death. One phosphorylation-dependent parkin interacting substrate target, MDM4 (a p53 inhibitor that associates with MDM2; also known as MDMX), is transcriptionally repressed in an histone deacetylase-dependent manner via parkin interacting substrate binding to insulin response sequence motifs within the MDM4 promoter. Virally-induced parkin interacting substrate transgenic mice develop c-Abl activity-dependent Parkinson's disease features such as motor deficits, dopaminergic neuron loss, and neuroinflammation. Parkin interacting substrate expression in the midbrain resulted in c-Abl activation, parkin interacting substrate phosphorylation, MDM4 repression, and p53 activation, all of which are blocked by the c-Abl inhibitor nilotinib. Importantly, we also observed aberrant c-Abl activation and parkin interacting substrate phosphorylation along with parkin interacting substrate accumulation in the midbrain of adult parkin knockout mice, implicating c-Abl in recessive Parkinson's disease. Inhibition of c-Abl or parkin interacting substrate phosphorylation by nilotinib or Y137F-parkin interacting substrate expression in adult parkin knockout mice blocked MDM4 repression and p53 activation, preventing motor deficits, and dopaminergic neurodegeneration. Finally, we found correlative increases in parkin interacting substrate phosphorylation, MDM4 repression, and p53 activation in postmortem Parkinson's disease brains, pointing to clinical relevance of the c-Abl-parkin interacting substrate-MDM4-p53 pathway. Taken together, our results describe a novel mechanism of epigenetic regulation of dopaminergic degeneration downstream of pathologic c-Abl activation in Parkinson's disease. Since c-Abl activation has been shown in sporadic Parkinson's disease, parkin interacting substrate phosphorylation might serve as both a useful biomarker and a potential therapeutic target to regulate neuronal loss in Parkinson's disease.

9.
J Clin Exp Neuropsychol ; 43(5): 469-480, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34355669

RESUMO

Introduction: Parkinson's disease (PD) is associated with a range of cognitive deficits. Few studies have carefully examined the subtle impacts of PD on cognition among patients who do not meet formal criteria for MCI or dementia. The aim of the current study was thus to describe the impact of PD on cognition in those without cognitive impairment in a well-characterized cohort.Methods: Non-cognitively impaired participants (122 with PD, 122 age- and sex-matched healthy volunteers) underwent extensive cognitive testing. Linear regression analyses compared diagnostic group performance across cognitive measures. For cognitive tasks that were significantly different between groups, additional analyses examined group differences restricting the group inclusion to PD participants with mild motor symptoms or disease duration less than 10 years.Results: Processing speed and semantic verbal fluency were significantly lower in the PD group (B = -3.77, 95% CIs [-5.76 to -1.77], p < .001, and B = -2.02, 95% CIs [-3.12, -0.92], p < .001, respectively), even after excluding those with moderate to severe motor symptoms (B = -2.73, 95% CIs [-4.94 to -0.53], p = .015 and B = -2.11, 95% CIs [-3.32 to -0.91], p < .001, respectively) or longer disease duration (B = -3.89, 95% CIs [-6.14 to -1.63], p < .001 and B = -1.58, 95% CIs [-2.78 to -0.37], p = .010, respectively). Semantic verbal fluency remained significantly negatively associated with PD diagnosis after controlling for processing speed (B = -1.66, 95% CIs [-2.79 to -0.53], p = .004).Conclusions: Subtle decline in specific cognitive domains may be present among people diagnosed with PD but without evidence to support a formal cognitive diagnosis. These results suggest the importance of early awareness of the potential for diminishing aspects of cognition in PD even among those without mild cognitive impairment or dementia.

10.
Sci Transl Med ; 13(604)2021 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-34321320

RESUMO

Accumulation of the parkin-interacting substrate (PARIS; ZNF746), due to inactivation of parkin, contributes to Parkinson's disease (PD) through repression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α; PPARGC1A) activity. Here, we identify farnesol as an inhibitor of PARIS. Farnesol promoted the farnesylation of PARIS, preventing its repression of PGC-1α via decreasing PARIS occupancy on the PPARGC1A promoter. Farnesol prevented dopaminergic neuronal loss and behavioral deficits via farnesylation of PARIS in PARIS transgenic mice, ventral midbrain transduction of AAV-PARIS, adult conditional parkin KO mice, and the α-synuclein preformed fibril model of sporadic PD. PARIS farnesylation is decreased in the substantia nigra of patients with PD, suggesting that reduced farnesylation of PARIS may play a role in PD. Thus, farnesol may be beneficial in the treatment of PD by enhancing the farnesylation of PARIS and restoring PGC-1α activity.


Assuntos
Doença de Parkinson , Animais , Dopamina , Camundongos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Prenilação , Proteínas Repressoras/metabolismo , Substância Negra/metabolismo
11.
J Clin Invest ; 131(13)2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34196307

RESUMO

Neurodegenerative disorders (NDs) affect essential functions not only in the CNS, but also cause persistent gut dysfunctions, suggesting that they have an impact on both CNS and gut-innervating neurons. Although the CNS biology of NDs continues to be well studied, how gut-innervating neurons, including those that connect the gut to the brain, are affected by or involved in the etiology of these debilitating and progressive disorders has been understudied. Studies in recent years have shown how CNS and gut biology, aided by the gut-brain connecting neurons, modulate each other's functions. These studies underscore the importance of exploring the gut-innervating and gut-brain connecting neurons of the CNS and gut function in health, as well as the etiology and progression of dysfunction in NDs. In this Review, we discuss our current understanding of how the various gut-innervating neurons and gut physiology are involved in the etiology of NDs, including Parkinson's disease, Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis, to cause progressive CNS and persistent gut dysfunction.


Assuntos
Sistema Nervoso Entérico/fisiopatologia , Doenças Neurodegenerativas/etiologia , Doenças Neurodegenerativas/fisiopatologia , Doença de Alzheimer/etiologia , Doença de Alzheimer/fisiopatologia , Esclerose Amiotrófica Lateral/etiologia , Esclerose Amiotrófica Lateral/fisiopatologia , Animais , Encéfalo/fisiopatologia , Sistema Digestório/inervação , Sistema Digestório/fisiopatologia , Modelos Animais de Doenças , Progressão da Doença , Disbiose/fisiopatologia , Microbioma Gastrointestinal/fisiologia , Humanos , Doença de Huntington/etiologia , Doença de Huntington/fisiopatologia , Modelos Neurológicos , Mutação , Doenças Neurodegenerativas/microbiologia , Doença de Parkinson/etiologia , Doença de Parkinson/fisiopatologia
12.
Neurotherapeutics ; 18(3): 1834-1848, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34260042

RESUMO

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS), characterized by demyelination, gliosis, and neurodegeneration. While the currently available disease-modifying therapies effectively suppress the immune attack on the CNS, there are no therapies to date that directly mitigate neurodegeneration. Glucagon-like peptide-1 (GLP-1) is a small peptide hormone that maintains glucose homeostasis. A novel GLP-1 receptor (GLP-1R) agonist, NLY01, was recently shown to have neuroprotective effects in the animal models of Parkinson's disease and is now in a phase 2 clinical trial. In this study, we investigated the therapeutic potential of NLY01 in a mouse model of MS, experimental autoimmune encephalomyelitis (EAE). Our data show that NLY01 delays the onset and attenuates the severity of EAE in a prevention paradigm, when given before disease onset. NLY01 inhibits the activation of immune cells in the spleen and reduces their trafficking into the CNS. In addition, we show that NLY01 suppresses the production of chemokines that are involved in leukocyte recruitment to the site of inflammation. The anti-inflammatory effect of NLY01 at the early stage of EAE may block the expression of the genes associated with neurotoxic astrocytes in the optic nerves, thereby preventing retinal ganglion cell (RGC) loss in the progressive stage of EAE. In the therapeutic paradigm, NLY01 significantly decreases the clinical score and second attack in a model of relapsing-remitting EAE. GLP-1R agonists may have dual efficacy in MS by suppressing peripheral and CNS inflammation, thereby limiting neuronal loss.

13.
FEBS J ; 2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34323016

RESUMO

ADP-ribosylation, a modification of proteins, nucleic acids, and metabolites, confers broad functions, including roles in stress responses elicited, for example, by DNA damage and viral infection and is involved in intra- and extracellular signaling, chromatin and transcriptional regulation, protein biosynthesis, and cell death. ADP-ribosylation is catalyzed by ADP-ribosyltransferases (ARTs), which transfer ADP-ribose from NAD+ onto substrates. The modification, which occurs as mono- or poly-ADP-ribosylation, is reversible due to the action of different ADP-ribosylhydrolases. Importantly, inhibitors of ARTs are approved or are being developed for clinical use. Moreover, ADP-ribosylhydrolases are being assessed as therapeutic targets, foremost as antiviral drugs and for oncological indications. Due to the development of novel reagents and major technological advances that allow the study of ADP-ribosylation in unprecedented detail, an increasing number of cellular processes and pathways are being identified that are regulated by ADP-ribosylation. In addition, characterization of biochemical and structural aspects of the ARTs and their catalytic activities have expanded our understanding of this protein family. This increased knowledge requires that a common nomenclature be used to describe the relevant enzymes. Therefore, in this viewpoint, we propose an updated and broadly supported nomenclature for mammalian ARTs that will facilitate future discussions when addressing the biochemistry and biology of ADP-ribosylation. This is combined with a brief description of the main functions of mammalian ARTs to illustrate the increasing diversity of mono- and poly-ADP-ribose mediated cellular processes.

14.
Biol Psychiatry ; 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-34247782

RESUMO

BACKGROUND: Gene dosage imbalance caused by copy number variations (CNVs) is a prominent contributor to brain disorders. In particular, 15q11.2 CNV duplications and deletions have been associated with autism spectrum disorder and schizophrenia, respectively. The mechanism underlying these diametric contributions remains unclear. METHODS: We established both loss-of-function and gain-of-function mouse models of Cyfip1, one of four genes within 15q11.2 CNVs. To assess the functional consequences of altered CYFIP1 levels, we performed systematic investigations on behavioral, electrophysiological, and biochemical phenotypes in both mouse models. In addition, we utilized RNA immunoprecipitation sequencing (RIP-seq) analysis to reveal molecular targets of CYFIP1 in vivo. RESULTS: Cyfip1 loss-of-function and gain-of function mouse models exhibited distinct and shared behavioral abnormalities related to autism spectrum disorder and schizophrenia. RIP-seq analysis identified messenger RNA targets of CYFIP1 in vivo, including postsynaptic NMDA receptor (NMDAR) complex components. In addition, these mouse models showed diametric changes in levels of postsynaptic NMDAR complex components at synapses because of dysregulated protein translation, resulting in bidirectional alteration of NMDAR-mediated signaling. Importantly, pharmacological balancing of NMDAR signaling in these mouse models with diametric Cyfip1 dosages rescues behavioral abnormalities. CONCLUSIONS: CYFIP1 regulates protein translation of NMDAR and associated complex components at synapses to maintain normal synaptic functions and behaviors. Our integrated analyses provide insight into how gene dosage imbalance caused by CNVs may contribute to divergent neuropsychiatric disorders.

15.
Elife ; 102021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34184634

RESUMO

Retinitis pigmentosa (RP) and associated inherited retinal diseases (IRDs) are caused by rod photoreceptor degeneration, necessitating therapeutics promoting rod photoreceptor survival. To address this, we tested compounds for neuroprotective effects in multiple zebrafish and mouse RP models, reasoning drugs effective across species and/or independent of disease mutation may translate better clinically. We first performed a large-scale phenotypic drug screen for compounds promoting rod cell survival in a larval zebrafish model of inducible RP. We tested 2934 compounds, mostly human-approved drugs, across six concentrations, resulting in 113 compounds being identified as hits. Secondary tests of 42 high-priority hits confirmed eleven lead candidates. Leads were then evaluated in a series of mouse RP models in an effort to identify compounds effective across species and RP models, that is, potential pan-disease therapeutics. Nine of 11 leads exhibited neuroprotective effects in mouse primary photoreceptor cultures, and three promoted photoreceptor survival in mouse rd1 retinal explants. Both shared and complementary mechanisms of action were implicated across leads. Shared target tests implicated parp1-dependent cell death in our zebrafish RP model. Complementation tests revealed enhanced and additive/synergistic neuroprotective effects of paired drug combinations in mouse photoreceptor cultures and zebrafish, respectively. These results highlight the value of cross-species/multi-model phenotypic drug discovery and suggest combinatorial drug therapies may provide enhanced therapeutic benefits for RP patients.


Assuntos
Fármacos Neuroprotetores/farmacologia , Retinite Pigmentosa/tratamento farmacológico , Animais , Animais Geneticamente Modificados , Células Cultivadas/efeitos dos fármacos , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/genética , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/metabolismo , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Regulação da Expressão Gênica/efeitos dos fármacos , Camundongos , Mutação , Poli(ADP-Ribose) Polimerase-1/genética , Poli(ADP-Ribose) Polimerase-1/metabolismo , Células Fotorreceptoras Retinianas Bastonetes/efeitos dos fármacos , Peixe-Zebra
16.
Proc Natl Acad Sci U S A ; 118(26)2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34172566

RESUMO

The spread of pathological α-synuclein (α-syn) is a crucial event in the progression of Parkinson's disease (PD). Cell surface receptors such as lymphocyte activation gene 3 (LAG3) and amyloid precursor-like protein 1 (APLP1) can preferentially bind α-syn in the amyloid over monomeric state to initiate cell-to-cell transmission. However, the molecular mechanism underlying this selective binding is unknown. Here, we perform an array of biophysical experiments and reveal that LAG3 D1 and APLP1 E1 domains commonly use an alkaline surface to bind the acidic C terminus, especially residues 118 to 140, of α-syn. The formation of amyloid fibrils not only can disrupt the intramolecular interactions between the C terminus and the amyloid-forming core of α-syn but can also condense the C terminus on fibril surface, which remarkably increase the binding affinity of α-syn to the receptors. Based on this mechanism, we find that phosphorylation at serine 129 (pS129), a hallmark modification of pathological α-syn, can further enhance the interaction between α-syn fibrils and the receptors. This finding is further confirmed by the higher efficiency of pS129 fibrils in cellular internalization, seeding, and inducing PD-like α-syn pathology in transgenic mice. Our work illuminates the mechanistic understanding on the spread of pathological α-syn and provides structural information for therapeutic targeting on the interaction of α-syn fibrils and receptors as a potential treatment for PD.

17.
J Proteome Res ; 20(7): 3428-3443, 2021 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-34061533

RESUMO

Parkinson's disease (PD) is the second most common neurodegenerative disorder that results in motor dysfunction and, eventually, cognitive impairment. α-Synuclein protein is known as a central protein to the pathophysiology of PD, but the underlying pathological mechanism still remains to be elucidated. In an effort to understand how α-synuclein underlies the pathology of PD, various PD mouse models with α-synuclein overexpression have been developed. However, systemic analysis of the brain proteome of those mouse models is lacking. In this study, we established two mouse models of PD by injecting α-synuclein preformed fibrils (PFF) or by inducing overexpression of human A53T α-synuclein to investigate common pathways in the two different types of the PD mouse models. For more accurate quantification of mouse brain proteome, the proteins were quantified using the method of stable isotope labeling with amino acids in mammals . We identified a total of 8355 proteins from the two mouse models; ∼6800 and ∼7200 proteins from α-synuclein PFF-injected mice and human A53T α-synuclein transgenic mice, respectively. Through pathway analysis of the differentially expressed proteins common to both PD mouse models, it was discovered that the complement and coagulation cascade pathways were enriched in the PD mice compared to control animals. Notably, a validation study demonstrated that complement component 3 (C3)-positive astrocytes were increased in the ventral midbrain of the intrastriatal α-synuclein PFF-injected mice and C3 secreted from astrocytes could induce the degeneration of dopaminergic neurons. This is the first study that highlights the significance of the complement and coagulation pathways in the pathogenesis of PD through proteome analyses with two sophisticated mouse models of PD.


Assuntos
Doença de Parkinson , alfa-Sinucleína , Animais , Modelos Animais de Doenças , Dopamina , Humanos , Camundongos , Camundongos Transgênicos , Doença de Parkinson/genética , alfa-Sinucleína/genética
18.
Front Neurol ; 12: 662034, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34025565

RESUMO

Parthanatos is a cell death signaling pathway in which excessive oxidative damage to DNA leads to over-activation of poly(ADP-ribose) polymerase (PARP). PARP then generates the formation of large poly(ADP-ribose) polymers that induce the release of apoptosis-inducing factor from the outer mitochondrial membrane. In the cytosol, apoptosis-inducing factor forms a complex with macrophage migration inhibitory factor that translocates into the nucleus where it degrades DNA and produces cell death. In a review of the literature, we identified 24 publications from 13 laboratories that support a role for parthanatos in young male mice and rats subjected to transient and permanent middle cerebral artery occlusion (MCAO). Investigators base their conclusions on the use of nine different PARP inhibitors (19 studies) or PARP1-null mice (7 studies). Several studies indicate a therapeutic window of 4-6 h after MCAO. In young female rats, two studies using two different PARP inhibitors from two labs support a role for parthanatos, whereas two studies from one lab do not support a role in young female PARP1-null mice. In addition to parthanatos, a body of literature indicates that PARP inhibitors can reduce neuroinflammation by interfering with NF-κB transcription, suppressing matrix metaloproteinase-9 release, and limiting blood-brain barrier damage and hemorrhagic transformation. Overall, most of the literature strongly supports the scientific premise that a PARP inhibitor is neuroprotective, even when most did not report behavior outcomes or address the issue of randomization and treatment concealment. Several third-generation PARP inhibitors entered clinical oncology trials without major adverse effects and could be repurposed for stroke. Evaluation in aged animals or animals with comorbidities will be important before moving into clinical stroke trials.

19.
Acta Neuropathol Commun ; 9(1): 78, 2021 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-33902708

RESUMO

Alzheimer's disease (AD) is the most common cause of age-related dementia. Increasing evidence suggests that neuroinflammation mediated by microglia and astrocytes contributes to disease progression and severity in AD and other neurodegenerative disorders. During AD progression, resident microglia undergo proinflammatory activation, resulting in an increased capacity to convert resting astrocytes to reactive astrocytes. Therefore, microglia are a major therapeutic target for AD and blocking microglia-astrocyte activation could limit neurodegeneration in AD. Here we report that NLY01, an engineered exedin-4, glucagon-like peptide-1 receptor (GLP-1R) agonist, selectively blocks ß-amyloid (Aß)-induced activation of microglia through GLP-1R activation and inhibits the formation of reactive astrocytes as well as preserves neurons in AD models. In two transgenic AD mouse models (5xFAD and 3xTg-AD), repeated subcutaneous administration of NLY01 blocked microglia-mediated reactive astrocyte conversion and preserved neuronal viability, resulting in improved spatial learning and memory. Our study indicates that the GLP-1 pathway plays a critical role in microglia-reactive astrocyte associated neuroinflammation in AD and the effects of NLY01 are primarily mediated through a direct action on Aß-induced GLP-1R+ microglia, contributing to the inhibition of astrocyte reactivity. These results show that targeting upregulated GLP-1R in microglia is a viable therapy for AD and other neurodegenerative disorders.

20.
STAR Protoc ; 2(2): 100405, 2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-33855307

RESUMO

Calcium regulation is a critical process in neurons, and Ca2+ signaling is a major contributor to neurological disorders including Parkinson's disease (PD). Here, combining calcium imaging with whole-cell Ca2+ current recording, we provide a detailed protocol for measuring Ca2+ homeostasis in dopaminergic (DA) neurons derived from human induced pluripotent stem cells (hiPSCs). This approach can be applied to investigate the role of Ca2+ homeostasis in neuronal functionality as well as in disease processes. For complete details on the use and execution of this protocol, please refer to Kim et al. (2020).

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