RESUMO
α-Synuclein aggregation at the synapse is an early event in Parkinson's disease and is associated with impaired striatal synaptic function and dopaminergic neuronal death. The cysteine string protein (CSPα) and α-synuclein have partially overlapping roles in maintaining synaptic function and mutations in each cause neurodegenerative diseases. CSPα is a member of the DNAJ/HSP40 family of co-chaperones and like α-synuclein, chaperones the SNARE complex assembly and controls neurotransmitter release. α-Synuclein can rescue neurodegeneration in CSPαKO mice. However, whether α-synuclein aggregation alters CSPα expression and function is unknown. Here we show that α-synuclein aggregation at the synapse is associated with a decrease in synaptic CSPα and a reduction in the complexes that CSPα forms with HSC70 and STGa. We further show that viral delivery of CSPα rescues in vitro the impaired vesicle recycling in PC12 cells with α-synuclein aggregates and in vivo reduces synaptic α-synuclein aggregates increasing monomeric α-synuclein and restoring normal dopamine release in 1-120hαSyn mice. These novel findings reveal a mechanism by which α-synuclein aggregation alters CSPα at the synapse, and show that CSPα rescues α-synuclein aggregation-related phenotype in 1-120hαSyn mice similar to the effect of α-synuclein in CSPαKO mice. These results implicate CSPα as a potential therapeutic target for the treatment of early-stage Parkinson's disease.
Assuntos
Corpo Estriado/metabolismo , Dopamina/metabolismo , Proteínas de Choque Térmico HSP40/metabolismo , Proteínas de Membrana/metabolismo , Agregação Patológica de Proteínas/metabolismo , alfa-Sinucleína/metabolismo , Animais , Corpo Estriado/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Agregação Patológica de Proteínas/patologia , Sinapses/metabolismo , Sinapses/patologiaRESUMO
1-Phenyl-8-azabicyclo[3.2.1]octane ethers are NK(1) receptor antagonists. Substitution at the 6-exo-position led to high affinity NK(1) antagonists with a prolonged duration of action in vivo. Incorporation of an alpha-methyl substituent in the pendent benzyl ether side chain gave compounds with increased selectivity over the hERG channel.
Assuntos
Compostos Aza/farmacologia , Compostos Bicíclicos com Pontes/farmacologia , Antagonistas dos Receptores de Neurocinina-1 , Animais , Células CHO , Cricetinae , Ciclização , Canais de Potássio Éter-A-Go-Go/efeitos dos fármacos , HumanosRESUMO
Extensive screening of compound libraries was undertaken to identify compounds with high affinity for the rat NK(1) receptor based on inhibition of [(125)I]-substance P binding. RP67580, SR140333, NKP-608 and GR205171 were selected as compounds of interest, with cloned rat NK(1) receptor binding K(i) values of 0.15-1.9 nM. Despite their high binding affinity, NKP-608 and GR205171 exhibited only a moderate functional antagonism of substance P-induced inositol-1-phosphate accumulation and acidification rate at 1 microM using cloned or native rat NK(1) receptors in vitro. The ability of the compounds to penetrate the CNS was determined by inhibition of NK(1) agonist-induced behaviours in gerbils and rats. GR205171 and NKP-608 potently inhibited GR73632-induced foot drumming in gerbils (ID(50) 0.04 and 0.2 mg/kg i.v., respectively). In contrast, RP67580 and SR140333 were poorly brain penetrant in gerbils (no inhibition at 10 mg/kg i.v.) and were not examined further in vivo. In rats, only high doses of GR205171 (10 or 30 mg/kg s.c.) inhibited NK(1) agonist-induced sniffing and hypertension, whilst NKP-608 (1 or 10 mg/kg i.p.) was without effect. GR205171 (3-30 mg/kg s.c.) caused only partial inhibition of separation-induced vocalisations in rat pups, a response that is known to be NK(1) receptor mediated in other species. These observations demonstrate the shortcomings of currently available NK(1) receptor antagonists for rat psychopharmacology assays.
Assuntos
Indóis/farmacologia , Antagonistas dos Receptores de Neurocinina-1 , Piperidinas/farmacologia , Quinolinas/farmacologia , Quinuclidinas/farmacologia , Tetrazóis/farmacologia , Animais , Células CHO , Cricetinae , Relação Dose-Resposta a Droga , Feminino , Gerbillinae , Humanos , Indóis/metabolismo , Isoindóis , Masculino , Piperidinas/metabolismo , Quinolinas/metabolismo , Quinuclidinas/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores da Neurocinina-1/metabolismo , Tetrazóis/metabolismo , Células Tumorais CultivadasRESUMO
A series of novel 4,4-disubstituted cyclohexylamines as NK(1) receptor antagonists is described: modifications to the amine moiety retain NK(1) receptor binding affinity whilst disrupting I(Kr) affinity.