RESUMO
Mutations in leucine-rich repeat kinase 2 (LRRK2) are a common cause of familial and sporadic Parkinson's disease (PD). Elevated LRRK2 kinase activity and neurodegeneration are linked, but the phosphosubstrate that connects LRRK2 kinase activity to neurodegeneration is not known. Here, we show that ribosomal protein s15 is a key pathogenic LRRK2 substrate in Drosophila and human neuron PD models. Phosphodeficient s15 carrying a threonine 136 to alanine substitution rescues dopamine neuron degeneration and age-related locomotor deficits in G2019S LRRK2 transgenic Drosophila and substantially reduces G2019S LRRK2-mediated neurite loss and cell death in human dopamine and cortical neurons. Remarkably, pathogenic LRRK2 stimulates both cap-dependent and cap-independent mRNA translation and induces a bulk increase in protein synthesis in Drosophila, which can be prevented by phosphodeficient T136A s15. These results reveal a novel mechanism of PD pathogenesis linked to elevated LRRK2 kinase activity and aberrant protein synthesis in vivo.
Assuntos
Neurônios/metabolismo , Doença de Parkinson/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Ribossômicas/metabolismo , Sequência de Aminoácidos , Animais , Drosophila melanogaster , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina , Dados de Sequência Molecular , Neurônios/patologia , Doença de Parkinson/patologia , Proteínas Ribossômicas/químicaRESUMO
Mutations in LRRK2 are the most common genetic causes of Parkinson's disease (PD). While the enzymatic activity of LRRK2 has been linked to PD, previous work has also provided support for an important role of elevated LRRK2 protein levels, independent of enzymatic activity, in PD pathogenesis. However, the mechanisms underlying the regulation of LRRK2 protein levels remain unclear. Here, we identify a role for the purine biosynthesis pathway enzyme ATIC in the regulation of LRRK2 levels and toxicity. AICAr, the precursor of ATIC substrate, regulates LRRK2 levels in a cell-type-specific manner in vitro and in mouse tissue. AICAr regulates LRRK2 levels through AUF1-mediated mRNA decay. Upon AICAr treatment, the RNA binding protein AUF1 is recruited to the AU-rich elements (ARE) of LRRK2 mRNA leading to the recruitment of the decapping enzyme complex DCP1/2 and decay of LRRK2 mRNA. AICAr suppresses LRRK2 expression and rescues LRRK2-induced dopaminergic neurodegeneration and neuroinflammation in PD Drosophila and mouse models. Together, this study provides insight into a novel regulatory mechanism of LRRK2 protein levels and function via LRRK2 mRNA decay that is distinct from LRRK2 enzymatic functions.
Assuntos
Doença de Parkinson , Animais , Camundongos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/genética , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Estabilidade de RNA , RNA Mensageiro/genética , MutaçãoRESUMO
The synaptic insertion or removal of AMPA receptors (AMPAR) plays critical roles in the regulation of synaptic activity reflected in the expression of long-term potentiation (LTP) and long-term depression (LTD). The cellular events underlying this important process in learning and memory are still being revealed. Here we describe and characterize the AAA+ ATPase Thorase, which regulates the expression of surface AMPAR. In an ATPase-dependent manner Thorase mediates the internalization of AMPAR by disassembling the AMPAR-GRIP1 complex. Following genetic deletion of Thorase, the internalization of AMPAR is substantially reduced, leading to increased amplitudes of miniature excitatory postsynaptic currents, enhancement of LTP, and elimination of LTD. These molecular events are expressed as deficits in learning and memory in Thorase null mice. This study identifies an AAA+ ATPase that plays a critical role in regulating the surface expression of AMPAR and thereby regulates synaptic plasticity and learning and memory.
Assuntos
Adenosina Trifosfatases/metabolismo , Plasticidade Neuronal , Receptores de AMPA/metabolismo , ATPases Associadas a Diversas Atividades Celulares , Adenosina Trifosfatases/química , Sequência de Aminoácidos , Animais , Encéfalo/metabolismo , Células Cultivadas , Feminino , Perfilação da Expressão Gênica , Humanos , Aprendizagem , Masculino , Memória , Camundongos , Dados de Sequência Molecular , Ratos , Alinhamento de Sequência , SinapsesRESUMO
The Hippo pathway is an evolutionarily conserved developmental pathway that controls organ size by integrating diverse regulatory inputs, including actomyosin-mediated cytoskeletal tension. Despite established connections between the actomyosin cytoskeleton and the Hippo pathway, the upstream regulation of actomyosin in the Hippo pathway is less defined. Here, we identify the phosphoinositide-3-phosphatase Myotubularin (Mtm) as a novel upstream regulator of actomyosin that functions synergistically with the Hippo pathway during growth control. Mechanistically, Mtm regulates membrane phospholipid PI(3)P dynamics, which, in turn, modulates actomyosin activity through Rab11-mediated vesicular trafficking. We reveal PI(3)P dynamics as a novel mode of upstream regulation of actomyosin and establish Rab11-mediated vesicular trafficking as a functional link between membrane lipid dynamics and actomyosin activation in the context of growth control. Our study also shows that MTMR2, the human counterpart of Drosophila Mtm, has conserved functions in regulating actomyosin activity and tissue growth, providing new insights into the molecular basis of MTMR2-related peripheral nerve myelination and human disorders.
Assuntos
Actomiosina , Via de Sinalização Hippo , HumanosRESUMO
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; â¼6800 and â¼7200 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/genéticaRESUMO
Mutations in LRRK2 are known to be the most common genetic cause of sporadic and familial Parkinson's disease (PD). Multiple lines of LRRK2 transgenic or knockin mice have been developed, yet none exhibit substantial dopamine (DA)-neuron degeneration. Here we develop human tyrosine hydroxylase (TH) promoter-controlled tetracycline-sensitive LRRK2 G2019S (GS) and LRRK2 G2019S kinase-dead (GS/DA) transgenic mice and show that LRRK2 GS expression leads to an age- and kinase-dependent cell-autonomous neurodegeneration of DA and norepinephrine (NE) neurons. Accompanying the loss of DA neurons are DA-dependent behavioral deficits and α-synuclein pathology that are also LRRK2 GS kinase-dependent. Transmission EM reveals that that there is an LRRK2 GS kinase-dependent significant reduction in synaptic vesicle number and a greater abundance of clathrin-coated vesicles in DA neurons. These transgenic mice indicate that LRRK2-induced DA and NE neurodegeneration is kinase-dependent and can occur in a cell-autonomous manner. Moreover, these mice provide a substantial advance in animal model development for LRRK2-associated PD and an important platform to investigate molecular mechanisms for how DA neurons degenerate as a result of expression of mutant LRRK2.
Assuntos
Modelos Animais de Doenças , Dopamina/metabolismo , Neurônios Dopaminérgicos/patologia , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/fisiologia , Doenças Neurodegenerativas/patologia , Norepinefrina/metabolismo , Fatores Etários , Animais , Comportamento Animal , Neurônios Dopaminérgicos/metabolismo , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Atividade Motora , Mutação , Doenças Neurodegenerativas/metabolismo , alfa-Sinucleína/metabolismoRESUMO
Mutations in LRRK2 cause autosomal dominant Parkinson's disease (PD). LRRK2 encodes a multi-domain protein containing GTPase and kinase domains, and putative protein-protein interaction domains. Familial PD mutations alter the GTPase and kinase activity of LRRK2 in vitro. LRRK2 is suggested to regulate a number of cellular pathways although the underlying mechanisms are poorly understood. To explore such mechanisms, it has proved informative to identify LRRK2-interacting proteins, some of which serve as LRRK2 kinase substrates. Here, we identify common interactions of LRRK2 with members of the dynamin GTPase superfamily. LRRK2 interacts with dynamin 1-3 that mediate membrane scission in clathrin-mediated endocytosis and with dynamin-related proteins that mediate mitochondrial fission (Drp1) and fusion (mitofusins and OPA1). LRRK2 partially co-localizes with endosomal dynamin-1 or with mitofusins and OPA1 at mitochondrial membranes. The subcellular distribution and oligomeric complexes of dynamin GTPases are not altered by modulating LRRK2 in mouse brain, whereas mature OPA1 levels are reduced in G2019S PD brains. LRRK2 enhances mitofusin-1 GTP binding, whereas dynamin-1 and OPA1 serve as modest substrates of LRRK2-mediated phosphorylation in vitro. While dynamin GTPase orthologs are not required for LRRK2-induced toxicity in yeast, LRRK2 functionally interacts with dynamin-1 and mitofusin-1 in cultured neurons. LRRK2 attenuates neurite shortening induced by dynamin-1 by reducing its levels, whereas LRRK2 rescues impaired neurite outgrowth induced by mitofusin-1 potentially by reversing excessive mitochondrial fusion. Our study elucidates novel functional interactions of LRRK2 with dynamin-superfamily GTPases that implicate LRRK2 in the regulation of membrane dynamics important for endocytosis and mitochondrial morphology.
Assuntos
Dinamina III/metabolismo , Dinamina II/metabolismo , Dinamina I/metabolismo , Neuroblastoma/metabolismo , Doença de Parkinson/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Western Blotting , Estudos de Casos e Controles , Células Cultivadas , Endocitose , Feminino , GTP Fosfo-Hidrolases/metabolismo , Células HEK293 , Humanos , Técnicas Imunoenzimáticas , Imunoprecipitação , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina , Camundongos , Camundongos Knockout , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Membranas Mitocondriais/metabolismo , Mutação , Neuritos/metabolismo , Neuroblastoma/patologia , Neurônios/citologia , Neurônios/metabolismo , Doença de Parkinson/patologia , Fosforilação , Domínios e Motivos de Interação entre Proteínas , Ratos , Ratos Sprague-Dawley , Saccharomyces cerevisiae , Técnicas do Sistema de Duplo-HíbridoRESUMO
Mutations in the leucine-rich repeat kinase 2 gene (LRRK2) are the most common genetic cause of Parkinson's disease (PD) and cause both autosomal dominant familial and sporadic PD. Currently, the physiological and pathogenic activities of LRRK2 are poorly understood. To decipher the biological functions of LRRK2, including the genes and pathways modulated by LRRK2 kinase activity in vivo, we assayed genome-wide mRNA expression in the brain and peripheral tissues from LRRK2 knockout (KO) and kinase hyperactive G2019S (G2019S) transgenic mice. Subtle but significant differences in mRNA expression were observed relative to wild-type (WT) controls in the cortex, striatum and kidney of KO animals, but only in the striatum in the G2019S model. In contrast, robust, consistent and highly significant differences were identified by the direct comparison of KO and G2019S profiles in the cortex, striatum, kidney and muscle, indicating opposite effects on mRNA expression by the two models relative to WT. Ribosomal and glycolytic biological functions were consistently and significantly up-regulated in LRRK2 G2019S compared with LRRK2 KO tissues. Genes involved in membrane-bound organelles, oxidative phosphorylation, mRNA processing and the endoplasmic reticulum were down-regulated in LRRK2 G2019S mice compared with KO. We confirmed the expression patterns of 35 LRRK2-regulated genes using quantitative reverse transcription polymerase chain reaction. These findings provide the first description of the transcriptional responses to genetically modified LRRK2 activity and provide preclinical target engagement and/or pharmacodynamic biomarker strategies for LRRK2 and may inform future therapeutic strategies for LRRK2-associated PD.
Assuntos
Doença de Parkinson/enzimologia , Doença de Parkinson/genética , Proteínas Serina-Treonina Quinases/metabolismo , Transcrição Gênica , Animais , Encéfalo/enzimologia , Feminino , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Proteínas Serina-Treonina Quinases/genéticaRESUMO
Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common causes of Parkinson's disease (PD) to date. Dysfunction in LRRK2 enzymatic activities and elevated protein levels are associated with the disease. How is LRRK2 activated, and what downstream molecular and cellular processes does LRRK2 regulate? Addressing these questions is crucial to decipher the disease mechanisms. In this review we focus on the upstream regulations and briefly discuss downstream substrates of LRRK2 as well as the cellular consequences caused by these regulations. Building on these basic findings, we discuss therapeutic strategies targeting LRRK2 and highlight the challenges in clinical trials. We further highlight the important questions that remains to be answered in the LRRK2 field.
RESUMO
Both sporadic and autosomal dominant forms of Parkinson's disease (PD) have been causally linked to mutations in leucine-rich repeat kinase 2 (LRRK2), a large protein with multiple domains. The kinase domain plays an important role in LRRK2-mediated toxicity. Although a number of investigations have focused on LRRK2 kinase activity, less is known about the GTPase function of LRRK2. The activity of GTPases is regulated by GTPase activating proteins (GAPs) and GTP exchange factors. Here, we identify ArfGAP1 as the first GAP for LRRK2. ArfGAP1 binds LRRK2 predominantly via the WD40 and kinase domain of LRRK2, and it increases LRRK2 GTPase activity and regulates LRRK2 toxicity both in vitro and in vivo in Drosophila melanogaster. Unexpectedly, ArfGAP1 is an LRRK2 kinase substrate whose GAP activity is inhibited by LRRK2, whereas wild-type and G2019S LRRK2 autophosphorylation and kinase activity are significantly reduced in the presence of ArfGAP1. Overexpressed ArfGAP1 exhibits toxicity that is reduced by LRRK2 both in vitro and in vivo. Δ64-ArfGAP1, a dominant-negative ArfGAP1, and shRNA knockdown of ArfGAP1 reduce LRRK2 toxicity. Thus, LRRK2 and ArfGAP1 reciprocally regulate the activity of each other. Our results provide insight into the basic pathobiology of LRRK2 and indicate an important role for the GTPase domain and ArfGAP1 in LRRK2-mediated toxicity. These data suggest that agents targeted toward regulation of LRRK2 GTP hydrolysis might be therapeutic agents for the treatment of PD.
Assuntos
Proteínas Ativadoras de GTPase/fisiologia , Proteínas Serina-Treonina Quinases/fisiologia , Animais , Células Cultivadas , Drosophila , Proteínas Ativadoras de GTPase/genética , Proteínas Ativadoras de GTPase/metabolismo , Células HEK293 , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina , Camundongos , Camundongos Knockout , Mutação/fisiologia , Neurônios/fisiologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Estrutura Terciária de Proteína/genética , Estrutura Terciária de Proteína/fisiologiaRESUMO
Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are associated with late-onset, autosomal-dominant, familial Parkinson's disease (PD) and also contribute to sporadic disease. The LRRK2 gene encodes a large protein with multiple domains, including functional Roc GTPase and protein kinase domains. Mutations in LRRK2 most likely cause disease through a toxic gain-of-function mechanism. The expression of human LRRK2 variants in cultured primary neurons induces toxicity that is dependent on intact GTP binding or kinase activities. However, the mechanism(s) underlying LRRK2-induced neuronal toxicity is poorly understood, and the contribution of GTPase and/or kinase activity to LRRK2 pathobiology is not well defined. To explore the pathobiology of LRRK2, we have developed a model of LRRK2 cytotoxicity in the baker's yeast Saccharomyces cerevisiae. Protein domain analysis in this model reveals that expression of GTPase domain-containing fragments of human LRRK2 are toxic. LRRK2 toxicity in yeast can be modulated by altering GTPase activity and is closely associated with defects in endocytic vesicular trafficking and autophagy. These truncated LRRK2 variants induce similar toxicity in both yeast and primary neuronal models and cause similar vesicular defects in yeast as full-length LRRK2 causes in primary neurons. The toxicity induced by truncated LRRK2 variants in yeast acts through a mechanism distinct from toxicity induced by human alpha-synuclein. A genome-wide genetic screen identified modifiers of LRRK2-induced toxicity in yeast including components of vesicular trafficking pathways, which can also modulate the trafficking defects caused by expression of truncated LRRK2 variants. Our results provide insight into the basic pathobiology of LRRK2 and suggest that the GTPase domain may contribute to the toxicity of LRRK2. These findings may guide future therapeutic strategies aimed at attenuating LRRK2-mediated neurodegeneration.
Assuntos
GTP Fosfo-Hidrolases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , GTP Fosfo-Hidrolases/genética , Genoma Fúngico , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina , Mutação , Neurônios/metabolismo , Proteínas Serina-Treonina Quinases/genética , Estrutura Terciária de Proteína , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismoRESUMO
Mutations in the LRRK2 (leucine-rich repeat kinase 2) gene are the most frequent genetic cause of PD (Parkinson's disease), and these mutations play important roles in sporadic PD. The LRRK2 protein contains GTPase and kinase domains and several protein-protein interaction domains. The kinase and GTPase activity of LRRK2 seem to be important in regulating LRRK2-dependent cellular signalling pathways. LRRK2's GTPase and kinase domains may reciprocally regulate each other to direct LRRK2's ultimate function. Although most LRRK2 investigations are centred on LRRK2's kinase activity, the present review focuses on the function of LRRK2's GTPase activity in LRRK2 physiology and pathophysiology.
Assuntos
GTP Fosfo-Hidrolases/metabolismo , Doença de Parkinson/enzimologia , Doença de Parkinson/patologia , Proteínas Serina-Treonina Quinases/metabolismo , GTP Fosfo-Hidrolases/genética , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina , Mutação , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Proteínas Serina-Treonina Quinases/genéticaRESUMO
Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have been identified as an important cause of late-onset, autosomal dominant familial Parkinson disease and contribute to sporadic Parkinson disease. LRRK2 is a large complex protein with multiple functional domains, including a Roc-GTPase, protein kinase, and multiple protein-protein interaction domains. Previous studies have suggested an important role for kinase activity in LRRK2-induced neuronal toxicity and inclusion body formation. Disease-associated mutations in LRRK2 also tend to increase kinase activity. Thus, enhanced kinase activity may therefore underlie LRRK2-linked disease. Similar to the closely related mixed-lineage kinases, LRRK2 can undergo autophosphorylation in vitro. Three putative autophosphorylation sites (Thr-2031, Ser-2032, and Thr-2035) have been identified within the activation segment of the LRRK2 kinase domain based on sequence homology to mixed-lineage kinases. Phosphorylation at one or more of these sites is critical for the kinase activity of LRRK2. Sensitive phospho-specific antibodies to each of these three sites have been developed and validated by ELISA, dot-blot, and Western blot analysis. Using these antibodies, we have found that all three putative sites are phosphorylated in LRRK2, and Ser-2032 and Thr-2035 are the two important sites that regulate LRRK2 kinase activity.
Assuntos
Doença de Parkinson/metabolismo , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Sequência de Aminoácidos , Animais , Anticorpos Fosfo-Específicos/genética , Anticorpos Fosfo-Específicos/imunologia , Western Blotting , Linhagem Celular , Células Cultivadas , Ativação Enzimática/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática , Humanos , Peróxido de Hidrogênio/farmacologia , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina , Camundongos , Dados de Sequência Molecular , Mutação/genética , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Homologia de Sequência de AminoácidosRESUMO
Mutations in the kinase LRRK2 and impaired endocytic trafficking are both implicated in the pathogenesis of Parkinson's disease (PD). Expression of the PD-associated LRRK2 mutant in mouse dopaminergic neurons was shown to disrupt clathrin-mediated endocytic trafficking. Here, we explored the molecular mechanism linking LRRK2 to endocytosis and found that LRRK2 bound to and phosphorylated the µ2 subunit of the adaptor protein AP2 (AP2M1), a core component of the clathrin-mediated endocytic machinery. Analysis of human SH-SY5Y cells and mouse neurons and tissues revealed that loss of LRRK2 abundance or kinase function resulted in decreased phosphorylation of AP2M1, which is required for the initial formation of clathrin-coated vesicles (CCVs). In contrast, overexpression of LRRK2 or expression of a Parkinson's disease-associated gain-of-function mutant LRRK2 (G2019S) inhibited the uncoating of AP2M1 from CCVs at later stages and prevented new cycles of CCV formation. Thus, the abundance and activity of LRRK2 must be calibrated to ensure proper endocytosis. Dysregulated phosphorylation of AP2M1 from the brain but not thyroid tissues of LRRK2 knockout and G2019S-knockin mice suggests a tissue-specific regulatory mechanism of endocytosis. Furthermore, we found that LRRK2-dependent phosphorylation of AP2M1 mediated dopaminergic neurodegeneration in a Drosophila model of PD. Together, our findings provide a mechanistic link between LRRK2, AP2, and endocytosis in the pathogenesis of PD.
Assuntos
Dopamina , Neurônios Dopaminérgicos , Animais , Neurônios Dopaminérgicos/metabolismo , Endocitose , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/genética , Camundongos , Mutação , FosforilaçãoRESUMO
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.
Assuntos
Células-Tronco Pluripotentes Induzidas , Doença de Parkinson , Animais , Encéfalo/metabolismo , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/genética , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Doença de Parkinson/genética , Biossíntese de ProteínasRESUMO
Mutations in LRRK2 play a critical role in both familial and sporadic Parkinson's disease (PD). Up to date, the role of LRRK2 in PD onset and progression remains largely unknown. However, experimental evidence highlights a critical role of LRRK2 in the control of vesicle trafficking, likely by Rab phosphorylation, that in turn may regulate different aspects of neuronal physiology. Here we show that LRRK2 interacts with Sec8, one of eight subunits of the exocyst complex. The exocyst complex is an evolutionarily conserved multisubunit protein complex mainly involved in tethering secretory vesicles to the plasma membrane and implicated in the regulation of multiple biological processes modulated by vesicle trafficking. Interestingly, Rabs and exocyst complex belong to the same protein network. Our experimental evidence indicates that LRRK2 kinase activity or the presence of the LRRK2 kinase domain regulate the assembly of exocyst subunits and that the over-expression of Sec8 significantly rescues the LRRK2 G2019S mutant pathological effect. Our findings strongly suggest an interesting molecular mechanism by which LRRK2 could modulate vesicle trafficking and may have important implications to decode the complex role that LRRK2 plays in neuronal physiology.
Assuntos
Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Proteínas de Membrana/metabolismo , Complexos Multiproteicos/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Animais , Linhagem Celular Tumoral , Células HEK293 , Humanos , Camundongos Knockout , Células PC12 , Ligação Proteica , RatosRESUMO
OBJECTIVE: To explore the differences of the main pharmacological action in wild and cultivated Atractylodes lancea. METHOD: Study the effect of the 70% ethanol extracts from the wild and the culticated A. lancea on the mice with gastriculcer induced by absolute ethyl alcohol or HCl. Stdudy the effect on intestinal propulsive function in mice by measuring the length of intestine and distance of Indian ink. Observe anti-bacteria effect in vitro of the A. lancea by determining the minimum inhibitory concentrations. RESULT: The pharmacological action, which made a little difference in the sane productive places, and made significant differences in different productive places. Compared to Jurong, it has better actions in Luotian on small intestinal propulsive function and bacteriostatic action. There was not an obvious difference in protective effect on gastric ulcer induced by absolute ethyl alcohol and 0.6 mol x L(-1) HC1 between different locations. CONCLUSION: To the main effect, cultvated A. lancea had no significant difference on the whole but having better result in some respects, which can provide the pharmacodynamics evidence of cultivated A. lancea being used instead of the wild.
Assuntos
Atractylodes/química , Medicamentos de Ervas Chinesas/farmacologia , Úlcera Gástrica/tratamento farmacológico , Animais , Modelos Animais de Doenças , Motilidade Gastrointestinal/efeitos dos fármacos , Humanos , Masculino , Camundongos , Úlcera Gástrica/induzido quimicamente , Úlcera Gástrica/patologia , Úlcera Gástrica/fisiopatologiaRESUMO
BACKGROUND: Mutations in PINK1 and parkin cause autosomal recessive Parkinson's disease (PD). Evidence placing PINK1 and parkin in common pathways regulating multiple aspects of mitochondrial quality control is burgeoning. However, compelling evidence to causatively link specific PINK1/parkin dependent mitochondrial pathways to dopamine neuron degeneration in PD is lacking. Although PINK1 and parkin are known to regulate mitophagy, emerging data suggest that defects in mitophagy are unlikely to be of pathological relevance. Mitochondrial functions of PINK1 and parkin are also tied to their proteasomal regulation of specific substrates. In this study, we examined how PINK1/parkin mediated regulation of the pathogenic substrate PARIS impacts dopaminergic mitochondrial network homeostasis and neuronal survival in Drosophila. METHODS: The UAS-Gal4 system was employed for cell-type specific expression of the various transgenes. Effects on dopamine neuronal survival and function were assessed by anti-TH immunostaining and negative geotaxis assays. Mitochondrial effects were probed by quantitative analysis of mito-GFP labeled dopaminergic mitochondria, assessment of mitochondrial abundance in dopamine neurons isolated by Fluorescence Activated Cell Sorting (FACS) and qRT-PCR analysis of dopaminergic factors that promote mitochondrial biogenesis. Statistical analyses employed two-tailed Student's T-test, one-way or two-way ANOVA as required and data considered significant when P < 0.05. RESULTS: We show that defects in mitochondrial biogenesis drive adult onset progressive loss of dopamine neurons and motor deficits in Drosophila models of PINK1 or parkin insufficiency. Such defects result from PARIS dependent repression of dopaminergic PGC-1α and its downstream transcription factors NRF1 and TFAM that cooperatively promote mitochondrial biogenesis. Dopaminergic accumulation of human or Drosophila PARIS recapitulates these neurodegenerative phenotypes that are effectively reversed by PINK1, parkin or PGC-1α overexpression in vivo. To our knowledge, PARIS is the only co-substrate of PINK1 and parkin to specifically accumulate in the DA neurons and cause neurodegeneration and locomotor defects stemming from disrupted dopamine signaling. CONCLUSIONS: Our findings identify a highly conserved role for PINK1 and parkin in regulating mitochondrial biogenesis and promoting mitochondrial health via the PARIS/ PGC-1α axis. The Drosophila models described here effectively recapitulate the cardinal PD phenotypes and thus will facilitate identification of novel regulators of mitochondrial biogenesis for physiologically relevant therapeutic interventions.
Assuntos
Neurônios Dopaminérgicos/patologia , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Degeneração Neural/patologia , Proteínas Repressoras/metabolismo , Animais , Animais Geneticamente Modificados , Neurônios Dopaminérgicos/metabolismo , Proteínas de Drosophila/deficiência , Proteínas de Drosophila/genética , Drosophila melanogaster , Humanos , Degeneração Neural/metabolismo , Biogênese de Organelas , Doença de Parkinson , Proteínas Serina-Treonina Quinases/deficiência , Proteínas Serina-Treonina Quinases/genética , Ubiquitina-Proteína Ligases/deficiência , Ubiquitina-Proteína Ligases/genéticaRESUMO
OBJECTIVE: Gaultheria yunnanensis. are used widespreadly in the south of China to treat rheumatoid arthritis. The aim of this study was to provide an experimental basis for G. yunnanensis to therapy rheumatoid arthritis. METHOD: We prepared water extracts, ethanol extracts, n-butanol extracts, ethyl acetate extracts and the rest of ethanol extracts from G. yunnanensis. Then, the n-butanol extracts were applied to macroporous resin and eluted with water, 30% ethanol, and 95% ethanol. Rheumatoid arthritis was induced by Freund's complete adjuvant injected into right postpedes in Wistar rats which was utilized to elucidate the anti-inflammatory effect of different extracted liquid of G. yunnanensis. Rats were intragastric injected (ig) with extracts as experimental group or normal saline as control group. RESULT: Freund's complete adjuvant induced arthritis was successfully established: paw edema were increased after Freund's complete adjuvant injection, peaked at 2 or 3 day, then decreased, the paw edema were increased again at 7 or 8 day, and persisted 15 d. Water extracts, n-butanol extracts or ethyl acetate extracts could a significantlly decrease the paw edema as compared with the control group (P < 0.05, P < 0.01). The effect of n-butanol extracts was the most powerful. Further, n-butanol extracts eluant with water and 30% ethanol decreased the paw edema. The activity of extracts eluant with 30% ethanol was stronger than that of eluant with water. CONCLUSION: G. yunnanensis displays considerable effects against Freund s complete adjuvant induced arthritis in rats, which is in concordance with clinical practice. n-Butanol extracts and both of the eluants with water and 30% ethanol produce a significant decrease in the paw edema. 30% ethanol eluants show a stronger activity than others. The effects against rheumatoid arthritis of different parts of G. yunnanensis differ in degree. It is deserved to explore the potential mechanisms of anti-inflammtion of the G. yunnanensis, especially the n-butanol extracts eluant with 30% ethanol.
Assuntos
Artrite Experimental/tratamento farmacológico , Medicamentos de Ervas Chinesas/administração & dosagem , Gaultheria/química , Animais , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Feminino , Masculino , Distribuição Aleatória , Ratos , Ratos WistarRESUMO
We described chemical composition in Cangzhu in recent years, volatile oil is the important chemical composition, The beta-eudesmol, hinesol are active ingredient in volatile oil and there are 38 kind of glycosides. At the same time, we overview the applying of RAPD technology in atractylodes lancea. The results is that there are correlation in chemical composition, genetic differentiation and geographical distribution, there is some truth in bounded by a territorial division of the north-south Cangzhu, and genetic differentiation has been happened in atractylodes lancea to adapting the environment. We described advances of pharmacological in dampness spleen, cardiovascular system, genitourinary system, nervous system, and the results show that there are pharmacological activity in digestive system, cardiovascular system, genitourinary system of atractylodes lancea.