Nigrostriatal 6-hydroxydopamine lesions increase alpha-synuclein levels and permeability in rat colon

Increasing evidence suggests that the gut-brain axis plays a crucial role in Parkinson's disease (PD). The abnormal accumulation of aggregated alpha-synuclein (aSyn) in the brain is a key pathological feature of PD. Intracerebral 6-hydroxydopamine (6-OHDA) is a widely used dopaminergic lesion model of PD. It exerts no aSyn pathology in the brain, but changes in the gut have not been assessed. Here, 6-OHDA was administered unilaterally either to the rat medial forebrain bundle (MFB) or striatum. Increased levels of glial fibrillary acidic protein in the ileum and colon were detected at 5 weeks postlesion. 6-OHDA decreased the Zonula occludens protein 1 barrier integrity score, suggesting increased colonic permeability. The total aSyn and Ser129 phosphorylated aSyn levels were elevated in the colon after the MFB lesion. Both lesions generally increased the total aSyn, pS129 aSyn, and ionized calcium-binding adapter molecule 1 (Iba1) levels in the lesioned striatum. In conclusion, 6-OHDA-induced nigrostriatal dopaminergic damage leads to increased aSyn levels and glial cell activation particularly in the colon, suggesting that the gut-brain axis interactions in PD are bidirectional and the detrimental process may start in the brain.

Genome, Environment, Microbiome and Metabolome in Autism (GEMMA) Study Design: Biomarkers Identification for Precision Treatment and Primary Prevention of Autism Spectrum Disorders by an Integrated Multi-Omics Systems Biology Approach

Autism Spectrum Disorder (ASD) affects approximately 1 child in 54, with a 35-fold increase since 1960. Selected studies suggest that part of the recent increase in prevalence is likely attributable to an improved awareness and recognition, and changes in clinical practice or service availability. However, this is not sufficient to explain this epidemiological phenomenon. Research points to a possible link between ASD and intestinal microbiota because many children with ASD display gastro-intestinal problems. Current large-scale datasets of ASD are limited in their ability to provide mechanistic insight into ASD because they are predominantly cross-sectional studies that do not allow evaluation of perspective associations between early life microbiota composition/function and later ASD diagnoses. Here we describe GEMMA (Genome, Environment, Microbiome and Metabolome in Autism), a prospective study supported by the European Commission, that follows at-risk infants from birth to identify potential biomarker predictors of ASD development followed by validation on large multi-omics datasets. The project includes clinical (observational and interventional trials) and pre-clinical studies in humanized murine models (fecal transfer from ASD probands) and in vitro colon models. This will support the progress of a microbiome-wide association study (of human participants) to identify prognostic microbiome signatures and metabolic pathways underlying mechanisms for ASD progression and severity and potential treatment response.

Gut Vibes in Parkinson's Disease: The Microbiota-Gut-Brain Axis

Background

The complexity of the pathogenic mechanisms underlying neurodegenerative disorders such as Parkinson's disease (PD) is attributable to multifactorial changes occurring at a molecular level, influenced by genetics and environmental interactions. However, what causes the main hallmarks of PD is not well understood. Recent data increasingly suggest that imbalances in the gut microbiome composition might trigger and/or exacerbate the progression of PD.

Objective

The present review aims to (1) report emerging literature showing changes in microbiota composition of PD patients compared to healthy individuals and (2) discuss how these changes may initiate and/or perpetuate PD pathology.

Methods

We analyzed 13 studies published from 2015 and included in this review. Altered microbial taxa were compiled in a detailed table summarizing bacterial changes in fecal/mucosal samples. The methodology was systematically reviewed across the articles and was also included in a table to facilitate comparisons between studies.

Results

Multiple studies found a reduction in short-chain fatty-acid-producing bacteria that can rescue neuronal damage through epigenetic mechanisms. Overall, the studies showed that changes in the gut microbiota composition might influence colonic inflammation, gut permeability, and α-synuclein aggregation, contributing to the neurogenerative process.

Conclusion

Further studies with larger cohorts and high-resolution sequencing methods are required to better define gut microbiota changes in PD. Furthermore, additional longitudinal studies are required to determine the causal link between these changes and PD pathogenesis as well as to study the potential of the intestinal microbiota as a biomarker.

Early-life antibiotic exposure increases the risk of developing allergic symptoms later in life: A meta-analysis

This study systematically reviewed and quantified the relationship between exposure to antibiotics during the first 2 years of life and the risk of allergies/atopies including hay fever, eczema, food allergy, positive skin prick testing (SPT), or elevated allergen-specific serum/plasma immunoglobulin (Ig) E levels later in life. PubMed and Web of Science databases were searched for observational studies published from January 1966 through November 11, 2015. Overall pooled estimates of the odds ratios (ORs) were obtained using fixed or random-effects models. Early-life exposure to antibiotics appears to be related to an increased risk of allergic symptoms of hay fever, eczema, and food allergy later in life. The summary OR for the risk of hay fever (22 studies) was 1.23, 95% confidence interval (CI):1.13-1.34; I² : 77.0%. The summary OR for the risk of eczema (22 studies) was 1.26, 95% CI: 1.15-1.37; I² : 74.2%, and the summary OR for food allergy (3 studies) was 1.42, 95% CI: 1.08-1.87; I² : 80.8%. However, no association was found for antibiotics exposure early in life and objective atopy measurements including positive SPT or elevated allergen-specific serum/plasma IgE levels.

Deoxynivalenol and Its Modified Forms: Are There Major Differences?

Considering the diverse toxic effects of the Fusarium toxin deoxynivalenol (DON), its common occurrence in wheat-based products, and its stability during processing, DON constitutes an increasing health concern for humans and animals. In addition to the parent compound DON, human and animal exposure encompasses the acetylated fungal metabolites 3-acetyl-deoxynivalenol (3ADON) and 15-acetyl-deoxynivalenol (15ADON) as well as the plant-derived DON-glucoside (DON3G) and the bacterial product de-epoxy-DON (DOM-1). In the current study we used the well-established Caco-2 cell model to compare the effects of these naturally occurring forms of DON on cell viability and markers of barrier integrity, as well as on the release of the pro-inflammatory chemokine chemokine CXC motif ligand (CXCL8). Results show that 3ADON is less potent in inducing adverse effects on barrier integrity when compared to DON, whereas 15ADON appears to be slightly more potent than DON. In contrast, DON3G and DOM-1 exerted no measurable adverse effects on the intestinal barrier. It was also demonstrated that galacto-oligosaccharides (GOS) are able to protect epithelial cells against DON and its acetylated forms, which suggests that GOS are beneficial food additives in the protection of vulnerable segments of the human population against adverse effects of DON and its derivatives.

Role of inflammasome signaling in development and function of mast cells (151.11)

The inflammasome is a cytosolic molecular complex containing a ASC,caspase1 and NALP that mediate the maturation of the proinflammatory cytokines IL-1β by caspases-1. NALP3 is an intracellular receptor involved in the recognition of pathogen associated molecular patterns (PAMPs).The inflammasome signal transduction promotes the maturation of inflammatory cytokines 1L-1β.The levels of 1L-1β has been shown increased in lung disease like asthma and emphysema.Mast cells(MC)play as effector cells for IgE mediated allergic diseases.Besides, recent evidence indicates that MCs also function as important cells in immune surveillance. Not much is known about role of inflammasomes in biology and development of mast cells.In this study we investigated the role of NALP3/ASC in mast cells.Development and function of mast cells, derived from a culture of bone marrow cells of wild-type, ASC-/-, NALP3-/-mice was studied. Bone marrow cells were cultured in presence for 3 weeks. After 3 weeks the responsiveness of mast cells to IgE/Ag and LPS was studied.Results:We found that in ASC-/-,NALP3-/- mast cells,the cellular maturation and differentiation was decreased as evidenced by a lower expression of c-kit and FcϵRI. Degranulation and the production of TNF-α,IL-6 and IL-1β after stimulation by IgE/Ag or LPS was significantly lower in NALP3-/-,ASC-/- cells compared to control cells.Our study demonstrates that NALP3/Asc plays role in maturation,differentiation and function of mast cells in vitro.

Cigarette smoke modulates release of CXCL8 through the inflammasome signaling in human bronchial epithelial cells (16HBE14o) (89.57)

Chronic obstructive pulmonary disease (COPD) is a major health problem and cigarette smoke (CS) is the main risk factor for the development of COPD. Exposure to cigarette smoke activates inflammatory cells for production of CXCL8 with accompanying damage to the lung epithelium and recruitment of macrophages and neutrophils. The Inflammasome is a multiprotein complex consisting of caspase-1, and NALP molecules and promotes the maturation of inflammatory cytokines such as interleukin 1-β and IL-18. The role of IL-1β in induction of CXCL8 has been reported. The epithelium is a barrier to the entry of pathogens, and as a dynamic system for host response. The epithelium can produce natural antimicrobial factors and release pro-inflammatory cytokines. Therefore it is thought that the airway epithelium plays a role in modulating innate immunity. In this study we studied the effects of CS on the regulation of CXCL8 release via inflammasome signaling by HBE-14o cell lines. We found that in HBE-14o preincubation with anti-caspase-1 (Z-VAD-FMK) suppressed the release of CXCL8 induced by CSE. Moreover, CSE induced maturation of IL-1β (17 KD) and activates NALP3 molecules which is demonstrated by Western blotting. In conclusion this study indicates that inflammasome signaling may directly or indirectly promote the production of CXCL8 by human bronchial epithelial cells.

Free immunoglobulin light chains as target in the treatment of chronic inflammatory diseases

Immunoglobulin free light chains were long considered irrelevant bystander products of immunoglobulin synthesis by B lymphocytes. To date, different studies suggest that free light chains may have important functional activities. For instance, it has been shown that immunoglobulin free light chains can elicit mast cell-driven hypersensitivity responses leading to asthma and contact sensitivity. Free light chains also show other biologic actions such as anti-angiogenic and proteolytic activities or can be used as specific targeting vehicles. Levels of free light chain levels in body fluids increase markedly in diseases such as multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. In this review, we will focus on the unexpected biological activities of immunoglobulin free light chains with special attention to its possible role in the induction of chronic inflammatory diseases.