MicroRNA-125a-3p Modulate Amyloid ß-Protein through the MAPK Pathway in Alzheimer's Disease.

BACKGROUND: MicroRNA (miR)-125a-3p is reported to play an important role in some central nervous system diseases, such as Alzheimer's disease (AD). However, a study has not been conducted on the mechanism of miR-125a-3p in the pathological process of AD. METHODS: First, we assessed the expression of miR-125a-3p in AD cohort. Subsequently, we altered the expressions of miR-125a-3p to assess its role in cell viability, cell apoptosis, amyloid-ß (Aß) metabolism, and synaptic activity. Finally, we identified its potential mechanism underlying AD pathology. RESULTS: This study unveiled the potential function of miR-125a-3p through modulating amyloid precursor protein processing. Additionally, miR-125a-3p influenced cell survival and activated synaptic expression through the modulation of Aß metabolism in the mitogen-activated protein kinase (MAPK) pathway via fibroblast growth factor receptor 2. CONCLUSION: Our study indicates that targeting miR-125a-3p may be an applicable therapy for AD in the future. However, more in vitro and in vivo studies with more samples are needed to confirm these results.

Morphological and Structural Network Analysis of Sporadic Alzheimer's Disease Brains Based on the APOE4 Gene.

BACKGROUND: Alzheimer's disease (AD) is an increasingly common type of dementia. Apolipoprotein E (APOE) gene is a strong risk factor for AD. OBJECTIVE: Here, we explored alterations in grey matter structure (GMV) and networks in AD, as well as the effects of the APOEɛ4 allele on neuroimaging regions based on structural magnetic resonance imaging (sMRI). METHODS: All subjects underwent an sMRI scan. GMV and cortical thickness were calculated using voxel-based morphological analysis, and structural networks were constructed based on graph theory analysis to compare differences between AD and normal controls. RESULTS: The volumes of grey matter in the bilateral inferior temporal gyrus, right middle temporal gyrus, right inferior parietal lobule, right limbic lobe, right frontal lobe, left anterior cingulate gyrus, and bilateral olfactory cortex of patients with AD were significantly decreased. The cortical thickness in patients with AD was significantly reduced in the left lateral occipital lobe, inferior parietal lobe, orbitofrontal region, precuneus, superior parietal gyrus, right precentral gyrus, middle temporal gyrus, pars opercularis gyrus, insular gyrus, superior marginal gyrus, bilateral fusiform gyrus, and superior frontal gyrus. In terms of local properties, there were significant differences between the AD and control groups in these areas, including the right bank, right temporalis pole, bilateral middle temporal gyrus, right transverse temporal gyrus, left postcentral gyrus, and left parahippocampal gyrus. CONCLUSION: There were significant differences in the morphological and structural covariate networks between AD patients and healthy controls under APOEɛ4 allele effects.

A review of autophagy mechanism of statins in the potential therapy of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegeneration csharacterized by amyloid-ß (Aß) deposition and abnormally phosphorylated Tau protein aggregation. Autophagy, as an important cellular metabolic activity, is closely related to the production, secretion and clearance of Aß peptide and Tau phosphorylation level. Therefore, autophagy may become a potential target for AD treatment. A large number of molecules are involved in the mammalian target of rapamycin (mTOR)-dependent or mTOR-independent pathway of autophagy. More and more evidences show that statins can intervene autophagy by regulating the activity or expression level of autophagy-related proteins and genes. On the one hand, statins can induce autophagy through Sirtuin1 (SIRT1), P21, nuclear P53 and adenylate activated protein kinase (AMPK). On the other hand, statins inhibit the mevalonate metabolism pathway, thereby interfering with the prenylation of small GTPases, leading to autophagy dysfunction. Statins can also reduce the levels of LAMP2 and dynein, destroying autophagy. In this review, we focused on the role of autophagy in AD and the autophagy mechanism of statins in the potential treatment of AD.

Crry silencing alleviates Alzheimer's disease injury by regulating neuroinflammatory cytokines and the complement system.

Complement component (3b/4b) receptor 1 (CR1) expression is positively related to the abundance of phosphorylated microtubule-associated protein tau (tau), and CR1 expression is associated with susceptibility to Alzheimer's disease. However, the exact role of CR1 in tau protein-associated neurodegenerative diseases is unknown. In this study, we show that the mouse Cr1-related protein Y (Crry) gene, Crry, is localized to microglia. We also found that Crry protein expression in the hippocampus and cortex was significantly elevated in P301S mice (a mouse model widely used for investigating tau pathology) compared with that in wild-type mice. Tau protein phosphorylation (at serine 202, threonine 205, threonine 231, and serine 262) and expression of the major tau kinases glycogen synthase kinase-3 beta and cyclin-dependent-like kinase 5 were greater in P301S mice than in wild-type mice. Crry silencing by lentivirus-transfected short hairpin RNA led to greatly reduced tau phosphorylation and glycogen synthase kinase-3 beta and cyclin-dependent-like kinase 5 activity. Crry silencing reduced neuronal apoptosis and rescued cognitive impairment of P301S mice. Crry silencing also reduced the levels of the neuroinflammatory factors interleukin-1 beta, tumor necrosis factor alpha, and interleukin-6 and the complement components complement 3 and complement component 3b. Our results suggest that Crry silencing in the P301S mouse model reduces tau protein phosphorylation by reducing the levels of neuroinflammation and complement components, thereby improving cognitive function.

Explore the role of CR1 genetic variants in late-onset Alzheimer's disease susceptibility.

BACKGROUND: Complement component (3b/4b) receptor 1 (CR1) is an interesting candidate gene which has a close connection with Alzheimer's disease, and its polymorphisms have been reported to link to the late-onset Alzheimer's disease (LOAD) susceptibility. However, the findings of these related studies are inconsistent. Objective To explore the effect of CR1 genetic variants in LOAD susceptibility. MethodsWe searched relevant studies for the period up to 1 November 2020. And odds ratios (ORs) and their 95% confidence intervals (CIs) were utilized to assess the strength of the association. In addition, we carried out a case-control association study to assess their genetic association. RESULTS: Finally, a total of 30 articles with 30108 LOAD cases and 37895 controls were included. Significant allele frequency between LOAD patients and controls was observed in rs3818361 and rs6656401 (rs3818361, T vs. C: OR,1.18; 95% CI, 1.13-1.23; rs6656401, A vs. G: OR, 1.23; 95% CI, 1.10-1.36). Moreover, these results remain significant in subgroup of rs3818361 in Asia or America (OR,1.26; 95% CI,1.06-1.45; OR, 1.18; 95% CI, 1.13-1.24, respectively) and rs6656401 in Europe (OR = 1.26; 95% CI, 1.09-1.42). In addition, the two single nucleotide polymorphisms were proved to significantly increase LOAD risk in the overall population under the dominant model (OR = 1.12; 95% CI, 1.02-1.21; OR = 1.18, 95% CI, 1.15-1.22, respectively). Our case-control study showed that the distribution of rs6656401 genotype was significant (P = 0.000; OR, 6.889; 95% CI, 2.709-17.520), suggesting the A allele of rs6656401 is the risk allele. CONCLUSION: These available data indicate that rs6656401 in CR1 is significant to increase LOAD risk.

Analysis of Serum miRNAs in Alzheimer's Disease.

This paper was aimed to analyze the microRNA (miRNA) signatures in Alzheimer disease (AD) and find the significant expressions of miRNAs, their target genes, the functional enrichment analysis of the confirmed genes, and potential drug treatment. The miRNA expression information of the gene expression profile data was downloaded from the Gene Expression Omnibus database. The total data sample size is 1309, including 1021 AD samples and 288 normal samples. A total of 21 differentially expressed miRNAs were obtained, of which 16 (hsa-miR-6761-3p, hsa-miR-6747-3p, hsa-miR-6875-3p, hsa-miR-6754-3p, hsa-miR-6736-3p, hsa-miR-6762-3p, hsa-miR-6787-3p, hsa-miR-208a-5p, hsa-miR-6740-3p, hsa-miR-6778-3p, hsa-miR-595, hsa-miR-6753-3p, hsa-miR-4747-3p, hsa-miR-3646, hsa-miR-6716-3p and hsa-miR-4435) were up-regulated and 5 (hsa-miR-125a-3p, hsa-miR-22-3p, hsa-miR-24-3p, hsa-miR-6131 and hsa-miR-125b-1-3p) were down-regulated in AD. A total of 6 miRNAs (hsa-miR-595, hsa-miR-3646, hsa-miR-4435 hsa-miR-125a-3p, hsa-miR-22-3p and hsa-miR-24-3p) and 78 miRNA-disease-related gene sub-networks were predicted, and 116 ceRNA regulatory relationship pairs, and the ceRNA regulatory network were obtained. The results of enrichment analysis suggested that the main target pathways of several miRNAs differentially expressed in AD were mitogen-activated protein kinase signal pathway. According to the prediction results of Drug-Gene Interaction database 2.0, we obtained 53 pairs of drug-gene interaction, including 7 genes (PTGS2, EGFR, CALM1, PDE4D, FGFR2, HMGCR, cdk6) and 53 drugs. We hope our results are helpful to find a viable way to prevent, delay the onset, diagnose, and treat AD.

Impacts of CR1 genetic variants on cerebrospinal fluid and neuroimaging biomarkers in alzheimer's disease.

BACKGROUND: The complement component (3b/4b) receptor 1 gene (CR1) gene has been proved to affect the susceptibility of Alzheimer's disease (AD) in different ethnic and districts groups. However, the effect of CR1 genetic variants on amyloid ß (Aß) metabolism of AD human is still unclear. Hence, the aim of this study was to investigate genetic influences of CR1 gene on Aß metabolism. METHODS: All data of AD patients and normal controls (NC) were obtained from alzheimer's disease neuroimaging initiative database (ADNI) database. In order to assess the effect of each single nucleotide polymorphism (SNP) of CR1 on Aß metabolism, the PLINK software was used to conduct the quality control procedures to enroll appropriate SNPs. Moreover, the correlation between CR1 genotypes and Aß metabolism in all participants were estimated with multiple linear regression models. RESULTS: After quality control procedures, a total of 329 samples and 83 SNPs were enrolled in our study. Moreover, our results identified five SNPs (rs10494884, rs11118322, rs1323721, rs17259045 and rs41308433), which were linked to Aß accumulation in brain. In further analyses, rs17259045 was found to decrease Aß accumulation among AD patients. Additionally, our study revealed the genetic variants in rs12567945 could increase CSF Aß42 in NC population. CONCLUSIONS: Our study had revealed several novel SNPs in CR1 genes which might be involved in the progression of AD via regulating Aß accumulation. These findings will provide a new basis for the diagnosis and treatment AD.

Overview the effect of statin therapy on dementia risk, cognitive changes and its pathologic change: a systematic review and meta-analysis.

BACKGROUND: Many studies have reported on the role of statin therapy in dementia, but its efficacy remains controversial. We aimed to search for reliable and meaningful articles to assess the efficacy of statin therapy for dementia risk, cognitive items, and pathologic markers. METHODS: Related literature for this study was published in the period from January 1, 1987 to January 1, 2018. Odds ratio (OR) and 95% confidence interval (95% CI) estimates were pooled in either fixed or random effects models. RESULTS: A total of 23 relevant studies were included after the application of the search strategy. The pooled results showed that statin therapy would downregulate dementia risk according to an analysis of 1,314,431 dementia patients and 1,836,539 healthy controls (OR: 0.64, 95% CI: 0.50, 0.81). In addition, specific changes in mini-mental state examination (MMSE) score were observed in individuals with dementia with statin therapy (OR: 0.46, 95% CI: 0.17, 0.74). However, the results of this meta-analysis showed that statin therapy did not significantly modify the Alzheimer's Disease Assessment Scale (ADAS-cog) score (OR: -0.26, 95% CI: -1.13, 0.62). No significant association was found between statin therapy and activities of daily living performance (OR: -0.69, 95% CI: -4.12, 2.74). When investigating pathological markers, our results indicated a significant influence of statin therapy on plasma amyloid ß40 (Aß40) (OR: 9.27, 95% CI: 0.71, 17.84), plasma Aß42 (OR: 2.60, 95% CI: 1.07, 4.13), plasma low-density lipoprotein (LDL) cholesterol (OR: -16.95, 95% CI: -25.54, -8.37), plasma lathosterol (OR: -0.11, 95% CI: -0.14, -0.07), plasma 24s-hydroxycholesterol (OR: -10.41, 95% CI: -15.57, -5.25), and cerebrospinal fluid (CSF) lathosterol (OR: -0.07, 95% CI: -0.12, -0.01). CONCLUSIONS: The available data indicate that statin therapy may reduce dementia risk, altering cognitive items and pathologic markers.