Zhen He

BACKGROUND: Overexpression of alpha-synuclein (SNCA) in families with multiplication mutations causes parkinsonism and subsequent dementia, characterized by diffuse Lewy Body disease post-mortem. Genetic variability in SNCA contributes to risk of idiopathic Parkinson's disease (PD), possibly as a result of overexpression. SNCA downregulation is therefore a valid therapeutic target for PD. RESULTS: We have identified human and murine-specific siRNA molecules which reduce SNCA in vitro. As a proof of concept, we demonstrate that direct infusion of chemically modified (naked), murine-specific siRNA into the hippocampus significantly reduces SNCA levels. Reduction of SNCA in the hippocampus and cortex persists for a minimum of 1 week post-infusion with recovery nearing control levels by 3 weeks post-infusion. CONCLUSION: We have developed naked gene-specific siRNAs that silence expression of SNCA in vivo. This approach may prove beneficial toward our understanding of the endogenous functional equilibrium of SNCA, its role in disease, and eventually as a therapeutic strategy for alpha-synucleinopathies resulting from SNCA overexpression.

BACKGROUND: Genome-wide association studies (GWASs) have shown that genetic variants are important determinants of free fatty acid levels. The mechanisms underlying the associations between genetic variants and free fatty acid levels are incompletely understood. Here, we aimed to identify genetic markers that could influence diverse fatty acid levels in a Chinese population and uncover the molecular mechanisms in terms of DNA methylation and gene expression. RESULTS: We identified strong associations between single-nucleotide polymorphisms (SNPs) in the fatty acid desaturase (FADS) region and multiple polyunsaturated fatty acids. Expression quantitative trait locus (eQTL) analysis of rs174570 on FADS1 and FADS2 mRNA levels proved that minor allele of rs174570 was associated with decreased FADS1 and FADS2 expression levels (P < 0.05). Methylation quantitative trait locus (mQTL) analysis of rs174570 on DNA methylation levels in three selected regions of FADS region showed that the methylation levels at four CpG sites in FADS1, one CpG site in intragenic region, and three CpG sites in FADS2 were strongly associated with rs174570 (P < 0.05). Then, we demonstrated that methylation levels at three CpG sites in FADS1 were negatively associated with FADS1 and FADS2 expression, while two CpG sites in FADS2 were positively associated with FADS1 and FADS2 expression. Using mediation analysis, we further show that the observed effect of rs174570 on gene expression was tightly correlated with the effect predicted through association with methylation. CONCLUSIONS: Our findings suggest that genetic variants in the FADS region are major genetic modifiers that can regulate fatty acid metabolism through epigenetic gene regulation.

Background and Aim: Hairy enhancer of split-1 (HES1) is a downstream transcriptional factor of Notch signaling pathway, which was found to be related to chemoresistance. This study was aimed to investigate the role of HES1 in chemoresistance of colorectal cancer (CRC). Methods: Tissue microarray was used to analyze the clinical significance of HES1 in radical resected (R0) stage II/III CRC patients that received adjuvant chemotherapy. 5-fluorouracil (5-Fu) chemoresistance was examined in CRC cell lines (RKO and HCT8, LOVO) with stable over-expression and inhibition of HES1 gene by cytotoxicity test. Gene expression microarray was used to investigate the enriched pathways and different expressed of genes in cells with over-expressed HES1. Expression changes of the chemoresistance related genes were confirmed by qPCR and western blot analysis. Results: Stage II CRC patients with higher HES1 expression showed higher recurrence rate after chemotherapy. Colon cancer cell lines which over-expressed HES1 were more resistant to 5-Fu treatment in vitro. Gene expression microarray revealed that HES1 was related to the signaling pathways of epithelial-mesenchymal transition (EMT) and drug metabolism. Immunofluorescence assay showed HES1 over-expression lead to depressed E-cadherin and elevated N-cadherin. QPCR and western blot analysis confirmed that ABCC1, ABCC2 and P-gp1 were induced after HES1 over-expression. Conclusions: HES1 promotes chemoresistance to 5-Fu by prompting EMT and inducing of several ABC transporter genes. HES1 might be a novel therapeutic target in CRC treatment.

Objective: This study aimed to investigate the gut microbiome profile in different inflammatory phenotypes of treatment-naive newly diagnosed asthmatic adults, to gain insight on the associations between intestinal microbiota and phenotypic features that characterize asthma heterogeneity to develop new treatments for asthma. Methods: Fresh stool samples were obtained from 20 healthy subjects and 47 newly diagnosed asthmatic patients prior to any interventions. The asthmatics were divided into allergic and non-allergic cohorts. Intestinal microbiota was analyzed by 16S rRNA next-generation sequencing. Demographic and clinical parameters were collected. Alpha and beta diversity analysis were calculated to detect differences within sample phylotype richness and evenness between controls and asthmatic patients. Statistically significant differences between samples were analyzed for all used metrics, and features of gut bacterial community structure were evaluated in relation to extensive clinical characteristics of asthmatic patients. Results: Gut microbial compositions were significantly different between asthmatic and healthy groups. Alpha-diversity of the gut microbiome was significantly lower in asthmatics than in controls. The microbiome between allergic and non-allergic asthmatic patients were also different, and 28 differential species were identified. PPAR signaling pathway, carotenoid biosynthesis, and flavonoid biosynthesis were significantly positively correlated with allergy-associated clinical index, including FENO value, blood eosinophil counts, and serum IgE and IL-4 levels. A combination of Ruminococcus bromii, Brevundimonas vesicularis , and Clostridium disporicum showed an AUC of 0.743 in the specific allergic/non-allergic cohort. When integrating C. disporicum , flavone, flavonol biosynthesis, and serum IL-4 values, the AUC achieved 0.929 to classify asthmatics. At the same time, C. colinum and its associated functional pathway exhibited an AUC of 0.78 to distinguish allergic asthmatics from those without allergies. Conclusion: We demonstrated a distinct taxonomic composition of gut microbiota in different asthmatic phenotypes, highlighting their significant relationships. Our study may support considerations of intestinal microbial signatures in delineating asthma phenotypes. Keywords: asthma, phenotypes, gut microbiota, 16S rRNA next-generation sequencing, functional pathway