α-Synuclein expression in response to bacterial ligands and metabolites in gut enteroendocrine cells: an in vitro proof of concept study

Caudo-rostral migration of pathological forms of α-synuclein from the gut to the brain is proposed as an early feature in Parkinson’s disease pathogenesis, but the underlying mechanisms remain unknown. Intestinal epithelial enteroendocrine cells sense and respond to numerous luminal signals, including bacterial factors, and transmit this information to the brain via the enteric nervous system and vagus nerve. There is evidence that gut bacteria composition and their metabolites change in Parkinson’s disease patients, and these alterations can trigger α-synuclein pathology in animal models of the disorder. Here, we investigated the effect of toll-like receptor and free fatty acid receptor agonists on the intracellular level of α-synuclein and its release using mouse secretin tumour cell line 1 enteroendocrine cells. Secretin tumour cell line 1 enteroendocrine cells were treated for 24 or 48 h with toll-like receptor agonists (toll-like receptor 4 selective lipopolysaccharide; toll-like receptor 2 selective Pam3CysSerLys4) and the free fatty acid receptor 2/3 agonists butyrate, propionate and acetate. The effect of selective receptor antagonists on the agonists’ effects after 24 hours was also investigated. The level of α-synuclein protein was measured in cell lysates and cell culture media by western blot and enzyme-linked immunosorbent assay. The level of α-synuclein and tumour necrosis factor messenger RNA was measured by quantitative reverse transcription real-time polymerase chain reaction. Stimulation of secretin tumour cell line 1 enteroendocrine cells for 24 and 48 hours with toll-like receptor and free fatty acid receptor agonists significantly increased the amount of intracellular α-synuclein and the release of α-synuclein from the cells into the culture medium. Both effects were significantly reduced by antagonists selective for each receptor. Toll-like receptor and free fatty acid receptor agonists also significantly increased tumour necrosis factor transcription, and this was effectively inhibited by corresponding antagonists. Elevated intracellular α-synuclein increases the likelihood of aggregation and conversion to toxic forms. Factors derived from bacteria induce α-synuclein accumulation in secretin tumour cell line 1 enteroendocrine cells. Here, we provide support for a mechanism by which exposure of enteroendocrine cells to specific bacterial factors found in Parkinson’s disease gut dysbiosis might facilitate accumulation of α-synuclein pathology in the gut

Evaluation of an Adapted Semi-Automated DNA Extraction for Human Salivary Shotgun Metagenomics

Recent attention has highlighted the importance of oral microbiota in human health and disease, e.g., in Parkinson’s disease, notably using shotgun metagenomics. One key aspect for efficient shotgun metagenomic analysis relies on optimal microbial sampling and DNA extraction, generally implementing commercial solutions developed to improve sample collection and preservation, and provide high DNA quality and quantity for downstream analysis. As metagenomic studies are today performed on a large number of samples, the next evolution to increase study throughput is with DNA extraction automation. In this study, we proposed a semi-automated DNA extraction protocol for human salivary samples collected with a commercial kit, and compared the outcomes with the DNA extraction recommended by the manufacturer. While similar DNA yields were observed between the protocols, our semi-automated DNA protocol generated significantly higher DNA fragment sizes. Moreover, we showed that the oral microbiome composition was equivalent between DNA extraction methods, even at the species level. This study demonstrates that our semi-automated protocol is suitable for shotgun metagenomic analysis, while allowing for improved sample treatment logistics with reduced technical variability and without compromising the structure of the oral microbiome

The effect of resin infiltration on proximal caries lesions in primary and permanent teeth. A systematic review and meta-analysis of clinical Trials

INTRODUCTION/OBJECTIVES This systematic review aimed to critically appraise the evidence on resin infiltration for the clinical management of proximal caries lesions in primary and permanent teeth. DATA Search terms included resin infiltration, micro-invasive and proximal caries. Potentially eligible studies involved proximal caries lesions treated with resin infiltration. Risk of bias assessment was performed using the Cochrane risk of bias tool and the quality of evidence was assessed with GRADE. SOURCES Electronic Database search of published and unpublished literature was performed in April 22, 2018 within the following databases: MEDLINE via Pubmed, Cochrane Central Register of Controlled Trials, LILACS via BIREME, Open Grey, Clinical Trials.gov and National Research Register. STUDY SELECTION Of 135 articles initially retrieved, 10 were eligible for inclusion in the systematic review comprising the results of 9 studies, while 5 randomized controlled trials (RCTs) (6 articles) with unclear risk of bias contributed to the meta-analyses. Random effects meta-analyses were implemented and lesion progression treatment effects were estimated through Odds Ratios (ORs) along with associated 95% Confidence Intervals (95% CIs). CONCLUSIONS Overall, there was strong evidence that proximal caries lesion progression was less likely to occur in permanent teeth following treatment with resin infiltration plus oral hygiene measures as compared to non- invasive methods (oral hygiene instructions) for follow up 18 months to 2 years (3 studies: OR = 0.14; 95% CI: 0.08, 0.25; P < 0.001) as well as 3 years (4 studies: OR = 0.15; 95% CI: 0.06, 0.36; P < 0.001). The quality of the evidence was rated as moderate to low respectively

Understanding How Minds Vary Relates to Skill in Inferring Mental States, Personality, and Intelligence

The human ability to make inferences about the minds of conspecifics is remarkable. The majority of work in this area focuses on mental state representation (‘theory of mind’), but has had limited success in explaining individual differences in this ability, and is characterized by the lack of a theoretical framework that can account for the effect of variability inthe population of minds to which individuals are exposed.We draw analogies between faces and minds as complex social stimuli, and suggest thattheoretical and empirical progress on understanding the mechanisms underlying mind representation can be achieved by adopting a ‘Mind-space’framework; that minds, like faces, are represented withina multidimensional psychological space. This Mind-space framework can accommodate the representation of whole cognitive systems, and may help to explain individual differences in the consistency and accuracy with which the mental states of others are inferred. Mind-space may also have relevance for understanding human development, inter-group relations, and the atypical socialcognitionseen in several clinical conditions