Feng-Tao Liu

Effect of Trehalose on PC12 Cells Overexpressing Wild-Type or A53T Mutant α-synuclein

Accumulation of α-synuclein (α-Syn) is a common pathology for both familiar and sporadic Parkinson’s disease (PD), enhancing its clearance might be a promising strategy for treating PD. To assess the potential of trehalose in this regard, we investigated its effect on the PC12 cells overexpressing wild type (WT) or A53T mutant α-Syn and the implicated pathway it might mediated. We observed that trehalose promoted the clearance of A53T α-Syn but not WT α-Syn in PC12 cells, and confirmed the increased LC3 and Lysotracker RED positive autolysosomes by using lysotracker and LC3 staining, the enhanced expression of LC3-II in Western blot, and more autophagosomes under Transmission Electron Microscope in a dose dependent manner after the trehalose treatment. The activation of autophagy can be alleviated by applying macroautophagy inhibitor 3-methyladenine (3-MA). In addition, degradation of A53T and WT α-Syn was blocked after Ubiquitin Proteasome System (UPS) inhibitor (MG132) was applied in those PC12 cells overexpressing A53T or WT α-Syn, suggesting that A53T α-Syn could be degraded by both UPS and macroautophagy. But the effect of trehalose on A53T α-Syn is mainly mediated through the macroautophagy pathway, which is not a dominant way for WT α-Syn clearance. Further in vivo research will be needed to verify the effectiveness of trehalose in treating PD.

Involvement of mortalin/GRP75/mthsp70 in the mitochondrial impairments induced by A53T mutant α-synuclein

Mutations and excessive accumulation of α-synuclein (α-syn) can lead to the degeneration of dopaminergic neurons, indicating a pivotal role of α-syn in the pathogenesis of Parkinsons disease (PD). Although how α-syn contributes to PD is still elusive, mitochondrial impairments have been reported to be implicated in. Mortalin, a molecular chaperone mainly located in mitochondria, has been linked to the pathogenesis of PD in recent studies. Moreover, some proteomics studies indicate that mortalin is associated with PD-related proteins, including α-syn. Therefore it is of interest to understand the function of mortalin in the mitochondrial disruption induced by A53T α-syn overexpression. The present study modulated the expression of mortalin and detected the effect of mortalin on the mitochondrial impairments induced by A53T α-syn in SH-SY5Y cells. Our data revealed that A53T α-syn could disrupt mitochondrial dynamics and increase the neuronal susceptibility to neurotoxin rotenone. The expression of mortalin decreased significantly in dopaminergic cells overexpressing A53T α-syn; furthermore, the down-regulation of mortalin could attenuate the disrupted mitochondrial dynamics by reducing α-syn translocation to mitochondria, suggesting that a compensatory mechanism of mortalin might be implicated in the pathogenesis of PD.

Cerebral Metabolic Differences Associated with Cognitive Impairment in Parkinson’s Disease

Purpose To characterize cerebral glucose metabolism associated with different cognitive states in Parkinson’s disease (PD) using 18F-fluorodeoxyglucose (FDG) and Positron Emission Tomography (PET). Methods Three groups of patients were recruited in this study including PD patients with dementia (PDD; n = 10), with mild cognitive impairment (PD-MCI; n = 20), and with no cognitive impairment (PD-NC; n = 30). The groups were matched for age, sex, education, disease duration, motor disability, levodopa equivalent dose and Geriatric Depression Rating Scale (GDS) score. All subjects underwent a FDG-PET study. Maps of regional metabolism in the three groups were compared using statistical parametric mapping (SPM5). Results PD-MCI patients exhibited limited areas of hypometabolism in the frontal, temporal and parahippocampal gyrus compared with the PD-NC patients (p < 0.01). PDD patients had bilateral areas of hypometabolism in the frontal and posterior parietal-occipital lobes compared with PD-MCI patients (p < 0.01), and exhibited greater metabolic reductions in comparison with PD-NC patients (p < 0.01). Conclusions Compared with PD-NC patients, hypometabolism was much higher in the PDD patients than in PD-MCI patients, mainly in the posterior cortical areas. The result might suggest an association between posterior cortical hypometabolism and more severe cognitive impairment. PD-MCI might be important for early targeted therapeutic intervention and disease modification.

Fasudil, a Rho kinase inhibitor, promotes the autophagic degradation of A53T α-synuclein by activating the JNK 1/Bcl-2/beclin 1 pathway

Accumulation of α-synuclein (α-syn) is pivotally implicated in the pathogenesis of Parkinson׳s disease (PD), and enhancing its clearance might be a promising strategy in PD treatment. It has recently been shown that Rho kinase (ROCK) activation is involved in many neurodegenerative diseases, and some ROCK inhibitors might promote the degradation of abnormal protein aggregates. However, it is not known if fasudil, the only ROCK inhibitor available in clinical setting, could promote the degradation of α-syn, and ameliorate the α-syn induced neurotoxicity. In this regard, we investigated the effect of fasudil on neurite injury caused by A53T α-syn overexpression and the implicated pathway it might mediate. In the current study, we found that under the condition of A53T α-syn overexpression, the neurite outgrowth decreased significantly with the increasing expression of ROCK2. Fasudil, the ROCK inhibitor, ameliorated such neurotoxicity and promoted the clearance of A53T α-syn. Its underlying mechanism was supported by that fasudil could increase the macroautophagy activation via JNK 1 and Bcl-2 phosphorylation and beclin 1/Vps34 complex formation. Taken together, fasudil might be able to provide a novel and promising strategy for PD treatment by enhancing α-syn clearance and activating the JNK 1/Bcl-2/beclin 1 pathway.

Odor Identification Test in Idiopathic REM-Behavior Disorder and Parkinson's Disease in China

Background Olfactory dysfunction is common in Parkinsons disease (PD) and idiopathic rapid eye movement sleep behavior disorder (iRBD), which is a risk factor in the development of PD. However, a few studies have conflicting results when comparing dysosmia in the patients with iRBD and PD. There is no study investigating the olfactory function in Chinese patients with iRBD. Additionally, the Sniffin’ Sticks screening 12 test (SS-12) contains several odors that are not familiar to people in different cultures. Methods Odor identification was evaluated in iRBD patients (n = 54), PD patients (n = 54) and healthy controls (n = 54). With the identification data, a brief odor identification test was established and then validated in other subjects. Results Odor identification scores in iRBD patients were significantly higher than those in PD patients (P<0.001) but lower than those in controls (P<0.001). At the cut-off value of 7.5, the Sniffin’ Sticks clearly differentiated iRBD and PD patients from the controls, and the brief test could increase the specificity in diagnosing PD. Neither the Sniffin’ Sticks nor the brief test could clearly differentiate PD and iRBD patients from each other. Conclusions Olfaction is more impaired in PD patients than in iRBD patients, possibly due to the heterogeneity of iRBD patients. The Sniffin’ Sticks could be a useful tool for differentiating iRBD patients from the healthy population, and it could be useful for screening people at high-risk of PD in China, especially when combined with polysomnography. To reduce the expense and time required for the Sniffin’ Sticks test, this study shows that a brief test is feasible.

Downregulation of blood serum microRNA 29 family in patients with Parkinson’s disease

There is currently no reliable and easily applicable diagnostic marker for Parkinson’s disease (PD). The aims of the present study were to compare the expression profiles of the microRNA29 family (miR-29s) in blood serum from patients with PD with healthy controls and to clarify whether the expression of miR-29s is correlated with disease severity, duration or L-dopa therapy and whether expression depends on the gender and age of patients. The levels of blood serum miR-29s in 80 patients with PD and 80 unaffected controls were assessed by reverse transcription-quantitative real-time PCR. The PCR products were confirmed by cloning and sequencing. Additionally, the expression of miR-7 in the blood serum from PD patients and control subjects was assessed. Serum miR-29 levels were significantly downregulated in PD patients compared to healthy controls. The serum miR-29 levels in female PD patients were markedly higher than in male PD patients. The expression of serum miR-29a and miR-29c expression tended to decrease with disease severity. Moreover, we found that serum miR-7 levels did not differ between PD patients and control subjects. Therefore, the reduction of serum miR-29 levels, particularly miR-29a and miR-29c, warrants further investigation of its potential serving as biomarkers for PD.

Associations between cognitive impairment and motor dysfunction in Parkinson's disease

Numerous studies have been carried out to explore the potential association between neurologic deficits and variable clinical manifestations of Parkinsons disease (PD). The aim of our study was to investigate the association between cognitive performance and motor dysfunction in Chinese patients with PD.

Autophagic Modulation by Trehalose Reduces Accumulation of TDP-43 in a Cell Model of Amyotrophic Lateral Sclerosis via TFEB Activation

Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease characterized by the formation of protein inclusion and progressive loss of motor neurons, finally leading to muscle weakness and respiratory failure. So far, the effective drugs for ALS are yet to be developed. Impairment of transcriptional activator transcription factor EB (TFEB) has been demonstrated as a key element in the pathogenesis of ALS. Trehalose is an mechanistic target of rapamycin-independent inducer for autophagy, which showed autophagic activation and neuroprotective effect in a variety of neurodegenerative diseases. The mechanism for trehalose-induced autophagy enhancement is not clear, and its therapeutic effect on TAR DNA-binding protein-43 (TDP-43) proteinopathies has been poorly investigated. Here we examined the effect of trehalose on TDP-43 clearance in a cell culture model and identified that trehalose treatment significantly reduced TDP-43 accumulation in vitro through modulation of the autophagic degradation pathway. Further studies revealed that activation of TFEB induced by trehalose was responsible for the enhancement of autophagy and clearance of TDP-43 level. These results gave us the notion that TFEB is a central regular in trehalose-mediated autophagic clearance of TDP-43 aggregates, representing an important step forward in the treatment of TDP-43 related ALS diseases.

Update on Molecular Imaging in Parkinson’s Disease

Advances in radionuclide tracers have allowed for more accurate imaging that reflects the actions of numerous neurotransmitters, energy metabolism utilization, inflammation, and pathological protein accumulation. All of these achievements in molecular brain imaging have broadened our understanding of brain function in Parkinson’s disease (PD). The implementation of molecular imaging has supported more accurate PD diagnosis as well as assessment of therapeutic outcome and disease progression. Moreover, molecular imaging is well suited for the detection of preclinical or prodromal PD cases. Despite these advances, future frontiers of research in this area will focus on using multi-modalities combining positron emission tomography and magnetic resonance imaging along with causal modeling with complex algorithms.

Evaluation of PDQ-8 and its relationship with PDQ-39 in China: a three-year longitudinal study

BackgroundParkinson’s disease is characterized by motor and non-motor symptoms with wide ranging impacts on the health-related quality of life. The 39-item Parkinson’s disease Questionnaire (PDQ-39) is the most widely used PD-specific health-related quality-of-life questionnaire. The short-form 8-item Parkinson’s disease Questionnaire (PDQ-8) was found to produce results similar to that of the PDQ-39 cross-culturally. However, there is no evaluation of the PDQ-8 in the mainland of China.MethodsIn this longitudinal study, 283 patients with Parkinson’s disease were recruited. The PDQ-39, the PDQ-8 and other scales were administered. Patients attended the clinic once annually for three years to complete the scales.ResultsThe PDQ-8 was found to have good validity and reliability. There was a strong correlation between the summary indices of the PDQ-8 and the PDQ-39 (r=0.93, P<0.001). Results suggested that the PDQ-8 was also associated with other clinical scales of mobility, depression and cognition. The convergent validity and discriminant validity of the PDQ-8 were demonstrated by item-to-dimension correlations. There was acceptable internal consistency of the PDQ-8 (Cronbach’s α: 0.80; Item-scale correlation efficient: 0.56–0.72). The PDQ-8 replicated the results of the PDQ-39 well at all follow-up time points (intraclass correlation coefficient: 0.96–0.98). In addition, there was good test-retest reliability of the PDQ-8.ConclusionThe PDQ-8 is a valid and reliable instrument assessing health-related quality of life for PD patients in the mainland of China.