alpha‐synuclein
Dotaz
Zobrazit nápovědu
Parkinson ́s disease (PD) pathology progresses throughout the nervous system. Whereas motor symptoms are always present, there is a high variability in the prevalence of non-motor symptoms. It has been postulated that the progression of the pathology is based on a prion-like disease mechanism partly due to the seeding effect of endocytosed-alpha-synuclein (ASYN) on the endogenous ASYN. Here, we analyzed the role of endogenous ASYN in the progression of PD-like pathology in vivo and in vitro and compared the effect of endocytosed-ASYN as well as paraquat and rotenone on primary enteric, dopaminergic and cortical neurons from wild-type and ASYN-KO mice. Our results show that, in vivo, pathology progression did not occur in the absence of endogenous ASYN. Remarkably, the damage caused by endocytosed-ASYN, rotenone or paraquat was independent from endogenous ASYN and related to the alteration of the host ́s mitochondrial membrane potential. Dopaminergic neurons were very sensitive to these noxae compared to other neuronal subtypes. These results suggest that ASYN-mitochondrial interactions play a major role in initiating the pathological process in the host neuron and endogenous ASYN is essential for the transsynaptical transmission of the pathology. Our results also suggest that protecting mitochondrial function is a valid primary therapeutic target.
- MeSH
- alfa-synuklein * MeSH
- dopaminergní neurony patologie MeSH
- myši MeSH
- paraquat MeSH
- Parkinsonova nemoc * patologie MeSH
- rotenon terapeutické užití MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Parkinson's disease (PD) is associated with the formation and deposition of amyloid fibrils of the protein alpha-synuclein (AS). It has been proposed that oligomeric intermediates on the pathway to fibrilization rather than the fibrils themselves are the pathogenic agents of PD, but efficient methods for their detection are lacking. We have studied the interfacial properties of wild-type AS and the course of its aggregation in vitro using electrochemical analysis and dynamic light scattering. The oxidation signals of tyrosine residues of AS at carbon electrodes and the ability of fibrils to adsorb and catalyze hydrogen evolution at hanging mercury drop electrodes (HMDEs) decreased during incubation. HMDEs were particularly sensitive to pre-aggregation changes in AS. Already after 1 h of a standard aggregation assay in vitro (stirring at 37 degrees C), the electrocatalytic peak H increased greatly and shifted to less negative potentials. Between 3 and 9 h of incubation, an interval during which dynamic light scattering indicated AS oligomerization, peak H diminished and shifted to more negative potentials, and AS adsorbability decreased. We tentatively attribute the very early changes in the interfacial behavior of the protein after the first few hours of incubation to protein destabilization with disruption of long-range interactions. The subsequent changes can be related to the onset of oligomerization. Our results demonstrate the utility of electrochemical methods as new and simple tools for the investigation of amyloid formation.
The interaction of α-synuclein with mitochondria in both typical and atypical Parkinson's disease is a critical component of degeneration. The mechanism of cell-to-cell propagation of pathological α-synuclein in synucleinopathies is unclear. Intercellular exchange of mitochondria along tunnelling nanotubes has been described in other diseases, such as cancer; however, its role in synucleinopathies is unknown. Pathological α-synuclein species have been demonstrated previously to move from cell to cell via tunnelling nanotubes. This process was further explored using co-culture and monoculture systems to determine if α-synuclein binds to migrating mitochondria within tunnelling nanotubes. Super-resolution analysis via stimulated emission depletion microscopy showed interaction between α-synuclein with the mitochondrial outer membrane and the presence of alpha-synuclein associated with mitochondria in tunnelling nanotubes between 1321N1, differentiated THP-1 and SH-SY5Y cell types. siRNA knockdown of Miro1, a critical protein-bridging mitochondria to the motor adaptor complex, had no effect on mitochondrial density or α-synuclein association with mitochondria in tunnelling nanotubes. The results show that α-synuclein aggregates associate with mitochondria in intercellular tunnelling nanotubes, suggesting that mitochondria-mediated α-synuclein transfer between cells may contribute to cell-to-cell spread of α-synuclein aggregates and disease propagation.
In the present study the effect of pramipexole alginate nanodispersion (PAND) was studied on the transgenic Drosophila exhibiting the PD symptoms. The PD flies were allowed to feed on the diet having PAND at final concentration of 1, 2 and 3 μM. A dose dependent significant delay in the loss of climbing ability and improvement in the activity was observed in PD flies. A dose dependent significant change in the oxidative stress markers and dopamine content was also observed in the PD flies exposed to various doses PAND. The improvement in the PD symptoms was more in PD flies exposed to PAND compared to PD flies exposed to pramipexole alone.
- MeSH
- agonisté dopaminu škodlivé účinky terapeutické užití MeSH
- alfa-synuklein * MeSH
- Drosophila melanogaster * MeSH
- geneticky modifikovaná zvířata MeSH
- oxidační stres účinky léků MeSH
- Parkinsonova nemoc * farmakoterapie patologie MeSH
- parkinsonské poruchy farmakoterapie MeSH
- pramipexol MeSH
- spektrofotometrie infračervená MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
AIMS: Endoplasmic reticulum stress followed by the unfolded protein response is one of the cellular mechanisms contributing to the progression of α-synuclein pathology in Parkinson's disease and other Lewy body diseases. We aimed to investigate the activation of endoplasmic reticulum stress and its correlation with α-synuclein pathology in human post-mortem brain tissue. METHODS: We analysed brain tissue from 45 subjects-14 symptomatic patients with Lewy body disease, 19 subjects with incidental Lewy body disease, and 12 healthy controls. The analysed brain regions included the medulla, pons, midbrain, striatum, amygdala and entorhinal, temporal, frontal and occipital cortex. We analysed activation of endoplasmic reticulum stress via levels of the unfolded protein response-related proteins (Grp78, eIF2α) and endoplasmic reticulum stress-regulating neurotrophic factors (MANF, CDNF). RESULTS: We showed that regional levels of two endoplasmic reticulum-localised neurotrophic factors, MANF and CDNF, did not change in response to accumulating α-synuclein pathology. The concentration of MANF negatively correlated with age in specific regions. eIF2α was upregulated in the striatum of Lewy body disease patients and correlated with increased α-synuclein levels. We found the upregulation of chaperone Grp78 in the amygdala and nigral dopaminergic neurons of Lewy body disease patients. Grp78 levels in the amygdala strongly correlated with soluble α-synuclein levels. CONCLUSIONS: Our data suggest a strong but regionally specific change in Grp78 and eIF2α levels, which positively correlates with soluble α-synuclein levels. Additionally, MANF levels decreased in dopaminergic neurons in the substantia nigra. Our research suggests that endoplasmic reticulum stress activation is not associated with Lewy pathology but rather with soluble α-synuclein concentration and disease progression.
- MeSH
- alfa-synuklein * metabolismus MeSH
- biologické markery metabolismus MeSH
- chaperon endoplazmatického retikula BiP * metabolismus MeSH
- demence s Lewyho tělísky * patologie metabolismus MeSH
- eukaryotický iniciační faktor 2 * metabolismus MeSH
- lidé středního věku MeSH
- lidé MeSH
- mozek metabolismus patologie MeSH
- neurotrofní faktory metabolismus MeSH
- proteiny teplotního šoku * metabolismus MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- signální dráha UPR * fyziologie MeSH
- stres endoplazmatického retikula fyziologie MeSH
- upregulace * MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Accumulation of alpha-synuclein (α-syn) is central to the pathogenesis of Parkinson's disease (PD). Previous studies suggest that α-syn pathology may originate from the olfactory bulb (OB) or gut in response to an unknown pathogen and later progress to the different brain regions. Aging is viewed as the utmost threat to PD development. Therefore, studies depicting the role of age in α-syn accumulation and its progression in PD are important. In the present study, we gave intranasal rotenone microemulsion for 6 weeks in 12-month-old female BALB/c mice and found olfactory dysfunction after 4 and 6 weeks of rotenone administration. Interestingly, motor impairment was observed only after 6 weeks. The animals were sacrificed after 6 weeks to perform western blotting and immunohistochemical studies to detect α-syn pathology, neuroinflammation and neurodegeneration. We found α-syn accumulation in OB, striatum, substantia nigra (SN) and cortex. Importantly, we found significant glial cell activation and neurodegeneration in all the analysed regions which were absent in our previous published studies with 3 months old mice even after they were exposed to rotenone for 9 weeks indicating age is a crucial factor for α-syn induced neuroinflammation and neurodegeneration. We also observed increased iron accumulation in SN of rotenone-exposed aged mice. Moreover, inflammaging was observed in OB and striatum of 12-month-old BALB/c mice as compared to 3-month-old BALB/c mice. In conclusion, there is a difference in sensitivity between adult and aged mice in the development and progression of α-syn pathology and subsequent neurodegeneration, for which inflammaging might be the crucial probable mechanism.
- MeSH
- alfa-synuklein * metabolismus MeSH
- dopamin MeSH
- dopaminergní neurony metabolismus MeSH
- modely nemocí na zvířatech MeSH
- mozek metabolismus MeSH
- myši MeSH
- neurozánětlivé nemoci MeSH
- Parkinsonova nemoc * patologie MeSH
- rotenon toxicita MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
In the study, we employ an affordable, tissue-saving, and precise simultaneous multiplex immunofluorescence method with heat-induced antibody stripping to identify and structurally analyse nigral Lewy bodies in dopaminergic neurones. Analysis of different alpha-synuclein epitopes and proteoforms reveals an almost uniform, onion-like morphology of the Lewy bodies. The N-terminal and C-terminal domains are predominantly accessible to antibody binding in the peripheral shell of the bodies.
- MeSH
- alfa-synuklein * metabolismus analýza MeSH
- demence s Lewyho tělísky patologie MeSH
- dopaminergní neurony metabolismus patologie MeSH
- fluorescenční protilátková technika metody MeSH
- Lewyho tělíska * metabolismus patologie MeSH
- lidé MeSH
- substantia nigra * metabolismus patologie MeSH
- vysoká teplota MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- dopamin fyziologie MeSH
- finanční podpora výzkumu jako téma MeSH
- Lewyho tělíska chemie MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie MeSH
- mitochondrie metabolismus MeSH
- Parkinsonova nemoc genetika metabolismus MeSH
- sodíko-draslíková ATPasa metabolismus MeSH
- spektrofotometrie atomová MeSH
- techniky in vitro MeSH
- Check Tag
- lidé MeSH
