P2X4 receptor participates in autophagy regulation in Parkinson's disease.

Dysfunctional autophagy often occurs during the development of neurodegenerative diseases, such as Parkinson's disease, Huntington's disease, and Alzheimer's disease. The purinergic P2X4 receptor is an ATP-gated ion channel that is widely expressed in the microglia, astrocytes, and neurons of the central and peripheral nervous systems. P2X4R is involved in the regulation of cellular excitability, synaptic transmission, and neuroinflammation. However, the role played by P2X4R in Parkinson's disease remains poorly understood. Rat models of Parkinson's disease were established by injecting 6-hydroxydopamine into the substantia nigra pars compacta. P2X4R-targeted small interfering RNA (siRNA) was injected into the same area 1 week before injury induction to inhibit the expression of the P2X4 receptor. The results showed that the inhibition of P2X4 receptor expression in Parkinson's disease model rats reduced the rotation behavior induced by apomorphine treatment, increased the latency on the rotarod test, and upregulated the expression of tyrosine hydroxylase, brain-derived neurotrophic factor, LC3-II/LC3-I, Beclin-1, and phosphorylated tropomyosin receptor kinase B (TrkB) in brain tissue, while simultaneously reducing p62 levels. These findings suggest that P2X4 receptor activation might inhibit neuronal autophagy through the regulation of the brain-derived neurotrophic factor/TrkB signaling pathway, leading to dopaminergic neuron damage in the substantia nigra and the further inhibition of P2X4 receptor-mediated autophagy. These results indicate that P2X4 receptor might serve as a potential novel target for the treatment of Parkinson's disease. This study was approved by the Animal Ethics Committee of Affiliated Hospital of Qingdao University (approval No. QYFYWZLL26119) on April 12, 2016.

Pharmacological treatment of neuropsychiatric symptoms of dementia: a network meta-analysis protocol.

BACKGROUND: Neuropsychiatric symptoms (NPS) of dementia are a common issue in dementia patients which can lead to poor medical and functional outcomes. Pharmacological interventions are its treatment of choice. However, whether to use pharmacological treatments in this population and which drug should be preferred remain controversial. We therefore aimed to compare and rank pharmacological interventions for NPS according to their efficacy and acceptability profiles by quantifying information from randomized controlled trials (RCTs). METHODS: We will include all RCTs reported as double-blind and comparing one active drug with another or with placebo that compare cholinesterase inhibitors (ChEIs), N-methyl-D-aspartic acid (NMDA) receptor modulators, antipsychotics, antidepressants, and mood stabilisers. Studies will be retrieved by searching electronic databases, including Cochrane Central Register of Controlled Trials, PubMed, MEDLINE, Clinicaltrial.govs, EMBASE, and with no date or language restrictions. The primary outcomes were efficacy (change in overall symptoms) and acceptability (all-cause discontinuation). The network meta-analysis (NMA) will be conducted in R software within a Bayesian framework. The quality of evidence will be evaluated using the Cochrane risk of bias tool, and the GRADE approach. We will conduct subgroup analyses to assess the robustness of our findings. RESULTS: The results of this study will be published in a peer-reviewed journal. CONCLUSIONS: This systematic review will synthesize the available evidence on the comparative efficacy of different pharmacological approaches in the management of overall NPS, agitation, psychosis, apathy and depressive symptoms in dementia patients. The results of the present NMA will influence evidence-based treatment decisions for clinicians.

Genome-wide association study identifies CBFA2T3 affecting the rate of CSF Aß42 decline in non-demented elders.

Brain amyloid deposition is an early pathological event in Alzheimer's disease (AD), and abnormally low levels amyloid-ß42 peptide (Aß42) in cerebrospinal fluid (CSF) can be detected in preclinical AD. To identify the genetic determinants that regulate the rate of CSF Aß42 decline among non-demented elders, we conducted a genome-wide association study involved 321 non-demented elders from Alzheimer's Disease Neuroimaging Initiative (ADNI) 1/GO/2 cohorts restricted to non-Hispanic Caucasians. A novel genome-wide significant association of higher annualized percent decline of CSF Aß42 in the gene CBFA2T3 (CBFA2/RUNX1 translocation partner 3; rs13333659-T; p = 2.24 × 10-9) was identified. Besides displaying abnormal CSF Aß42 levels, rs13333659-T carriers were more likely to exhibit a greater longitudinal cognitive decline (p = 0.029, ß = 0.097) and hippocampal atrophy (p = 0.029, ß = -0.160) in the non-demented elders, especially for the participants who were amyloid-positive at baseline. These findings suggest rs13333659 in CBFA2T3 as a risk locus to modulate the decline rate of CSF Aß42 preceding the onset of clinical symptoms.

Genome-wide association study identifies Alzheimer's risk variant in MS4A6A influencing cerebrospinal fluid sTREM2 levels.

The triggering receptor expressed on myeloid cells 2 (TREM2) gene has been reported to increase the risk of Alzheimer's disease (AD). The soluble TREM2 protein (sTREM2) in cerebrospinal fluid (CSF) was also associated with AD. However, the role of sTREM2 in AD and its genetic modifiers remain unclear. We carried out a genome-wide association study for CSF sTREM2 levels using participants from the Alzheimer's Disease Neuroimaging Initiative and validated the significant association in an independent cohort from Chinese Alzheimer's Biomarker and LifestylE study. rs7232 in membrane spanning 4-domains A6A (MS4A6A) gene was associated with CSF sTREM2 levels at genome-wide significance (p = 1.42 × 10-15). The locus influences CSF sTREM2 levels especially in nondemented individuals. And the association was replicable in the validation cohort from Chinese Alzheimer's Biomarker and LifestylE study (p = 0.0106). Besides, the expressions of MS4A6A and TREM2 were correlated in brain regions (p < 2 × 10-16). The findings of our study suggest that the AD risk variant in the MS4A6A gene participates in the regulation of sTREM2.

Comparative safety and effectiveness of cholinesterase inhibitors and memantine for Alzheimer's disease: a network meta-analysis of 41 randomized controlled trials.

BACKGROUND: Cholinesterase inhibitors and memantine have been approved for management of Alzheimer's disease (AD), but there has been no consensus about the choice of various types and doses of drugs at different stages. Hence, we compared and ranked the efficacy and tolerability of these available drugs. METHODS: We searched PubMed, the Cochrane Central Register of Controlled Trials, and Embase for randomized controlled trials (RCTs) published from database inception to July 21, 2017. The primary outcomes were the mean overall changes in cognitive function and responders who had any adverse events. We conducted a random-effects network meta-analysis. RESULTS: Forty-one RCTs were included in this study. Compared with placebo, galantamine 32 mg daily (standardized mean difference - 0.51, 95% credible interval - 0.67 to - 0.35), galantamine 24 mg daily (- 0.50, - 0.61 to - 0.40), and donepezil 10 mg daily (- 0.40, - 0.51 to - 0.29) were probably the most effective agents on cognition for mild to moderate AD, and memantine 20 mg combined with donepezil 10 mg (0.76, 0.39 to 1.11) was recommended for moderate to severe patients. Memantine showed the best profile of acceptability. Rivastigmine transdermal 15-cm2 patch was the best optional treatment both in function and global changes. None of the medicines was likely to improve neuropsychiatric symptoms through this analysis. CONCLUSIONS: Pharmacological interventions have beneficial effects on cognition, function, and global changes, but not on neuropsychiatric symptoms, through current network meta-analysis. The choice of drugs may mainly depend on the disease severity and clinical symptoms.