Investigating the metabolite signature of an altered oral microbiota as a discriminant factor for multiple sclerosis: a pilot study.

In multiple sclerosis (MS), alterations of the gut microbiota lead to inflammation. However, the role of other microbiomes in the body in MS has not been fully elucidated. In a pilot case-controlled study, we carried out simultaneous characterization of faecal and oral microbiota and conducted an in-depth analysis of bacterial alterations associated with MS. Using 16S rRNA sequencing and metabolic inference tools, we compared the oral/faecal microbiota and bacterial metabolism pathways in French MS patients (n = 14) and healthy volunteers (HV, n = 21). A classification model based on metabolite flux balance was established and validated in an independent German cohort (MS n = 12, HV n = 38). Our analysis revealed decreases in diversity indices and oral/faecal compartmentalization, the depletion of commensal bacteria (Aggregatibacter and Streptococcus in saliva and Coprobacter and Roseburia in faeces) and enrichment of inflammation-associated bacteria in MS patients (Leptotrichia and Fusobacterium in saliva and Enterobacteriaceae and Actinomyces in faeces). Several microbial pathways were also altered (the polyamine pathway and remodelling of bacterial surface antigens and energetic metabolism) while flux balance analysis revealed associated alterations in metabolite production in MS (nitrogen and nucleoside). Based on this analysis, we identified a specific oral metabolite signature in MS patients, that could discriminate MS patients from HV and rheumatoid arthritis patients. This signature allowed us to create and validate a discrimination model on an independent cohort, which reached a specificity of 92%. Overall, the oral and faecal microbiomes were altered in MS patients. This pilot study highlights the need to study the oral microbiota and oral health implications in patients with autoimmune diseases on a larger scale and suggests that knowledge of the salivary microbiome could help guide the identification of new pathogenic mechanisms associated with the microbiota in MS patients.

Influence of physico-chemical properties of two lipoxin emulsion-loaded hydrogels on pre-polarized macrophages: a comparative analysis.

Inflammation, a crucial defense mechanism, must be rigorously regulated to prevent the onset of chronic inflammation and subsequent tissue damage. Specialized pro resolving mediators (SPMs) such as lipoxin A4 (LXA4) have demonstrated their ability to facilitate the resolution of inflammation by orchestrating a transition of M1 pro-inflammatory macrophages towards an anti-inflammatory M2 phenotype. However, the hydrophobic and chemically labile nature of LXA4 necessitates the development of a delivery system capable of preserving its integrity for clinical applications. In this study, two types of emulsion were formulated using different homogenization processes:mechanical overhead stirrer (MEB for blank Emulsion and MELX for LXA4 loaded-Emulsion) or Luer-lock syringes (SEB for blank Emulsion and SELX for LXA4 loaded-Emulsion)). Following characterization, including size and droplet morphology assessment by microscopy, the encapsulation efficiency (EE) was determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). To exert control over LXA4 release, these emulsions were embedded within silanized hyaluronic acid hydrogels. A comprehensive evaluation, encompassing gel time, swelling, and degradation profiles under acidic, basic, and neutral conditions, preceded the assessment of LXA4 cumulative release using LC-MS/MS. Physicochemical results indicate that H-MELX (Mechanical overhead stirrer LXA4 Emulsion loaded-Hydrogel) exhibits superior efficiency over H-SELX (Luer-lock syringes LXA4 Emulsion loaded-Hydrogel). While both formulations stimulated pro-inflammatory cytokine secretion and promoted a pro-inflammatory macrophage phenotype, LXA4 emulsion-loaded hydrogels displayed a diminished pro-inflammatory activity compared to blank emulsion-loaded hydrogels. These findings highlight the biological efficacy of LXA4 within both systems, with H-SELX outperforming H-MELX in terms of efficiency. To the best of our knowledge, this is the first successful demonstration of the biological efficacy of LXA4 emulsion-loaded hydrogel systems on macrophage polarization. These versatile H-MELX and H-SELX formulations can be customized to enhance their biological activity making them promising tools to promote the resolution of inflammation in diverse clinical applications.

Gestational cholestyramine treatment protects adult offspring of ApoE-deficient mice against maternal-hypercholesterolemia-induced atherosclerosis.

AIM: Perinatal hypercholesterolemia exacerbates the development of atherosclerotic plaques in adult offspring. Here, we aimed to study the effect of maternal treatment with cholestyramine, a lipid-lowering drug, on atherosclerosis development in adult offspring of hypercholesterolemic ApoE-deficient (ApoE-/-) mice. METHODS: ApoE-/- mice were treated with 3% cholestyramine (CTY) during gestation (G). After weaning, offspring (CTY-G) were fed control diet until sacrificed at 25weeks of age. Atherosclerosis development in the aortic root of offspring was assessed after oil-red-o staining, along with some of predefined atherosclerosis regulators such as LDL and HDL by high-performance liquid chromatography (HPLC), and bile acids (BA) and trimethylamine N-oxide (TMAO) by liquid chromatography-mass spectrometry (LC-MS/MS). RESULTS: In pregnant dams, cholestyramine treatment resulted in significantly lower plasma total- and LDL-cholesterol as well as gallbladder total BA levels. In offspring, both males and females born to treated dams displayed reduced atherosclerotic plaques areas along with less lipid deposition in the aortic root. No significant change in plasma total cholesterol or triglycerides was measured in offspring, but CTY-G males had increased HDL-cholesterol and decreased apolipoproteins B100 to A-I ratio. This latter group also showed reduced gallbladder total and specifically tauro-conjugated bile acid pools, whereas for CTY-G females, hydrophilic plasma tauro-conjugated BA pool was significantly higher. They also benefited from lower plasma TMAO. CONCLUSION: Prenatal cholestyramine treatment reduces atherosclerosis development in adult offspring of ApoE-/- mice along with modulating the plaques' composition as well as some related biomarkers such as HDL-C, bile acids and TMAO.

Adult rats sired by obese fathers present learning deficits associated with epigenetic and neurochemical alterations linked to impaired brain glutamatergic signaling.

AIM: Offspring of obese mothers are at high risk of developing metabolic syndrome and cognitive disabilities. Impaired metabolism has also been reported in the offspring of obese fathers. However, whether brain function can also be affected by paternal obesity has barely been examined. This study aimed to characterize the learning deficits resulting from paternal obesity versus those induced by maternal obesity and to identify the underlying mechanisms. METHODS: Founder control and obese female and male Wistar rats were mated to constitute three first-generation (F1) experimental groups: control mother/control father, obese mother/control father, and obese father/control mother. All F1 animals were weaned onto standard chow and underwent a learning test at 4 months of age, after which several markers of glutamate-mediated synaptic plasticity together with the expression of miRNAs targeting glutamate receptors and the concentration of kynurenic and quinolinic acids were quantified in the hippocampus and frontal cortex. RESULTS: Maternal obesity induced a severe learning deficit by impairing memory encoding and memory consolidation. The offspring of obese fathers also showed reduced memory encoding but not impaired long-term memory formation. Memory deficits in offspring of obese fathers and obese mothers were associated with a down-regulation of genes encoding NMDA glutamate receptors subunits and several learning-related genes along with impaired expression of miR-296 and miR-146b and increased concentration of kynurenic acid. CONCLUSION: Paternal and maternal obesity impair offspring's learning abilities by affecting different processes of memory formation. These cognitive deficits are associated with epigenetic and neurochemical alterations leading to impaired glutamate-mediated synaptic plasticity.

Allergic Sensitization Driving Immune Phenotyping and Disease Severity in a Mouse Model of Asthma.

PURPOSE: Asthma is a frequent chronic inflammatory bronchial disease affecting more than 300 million patients worldwide, 70% of whom are secondary to allergy. The diversity of asthmatic endotypes contributes to their complexity. The inter-relationship between allergen and other exposure and the airway microbiome adds to the phenotypic diversity and defines the natural course of asthma. Here, we compared the mouse models of house dust mite (HDM)-induced allergic asthma. Allergic sensitization was performed via various routes and associated with outcomes. METHODS: Mice were sensitized with HDM via the oral, nasal or percutaneous routes. Lung function, barrier integrity, immune response and microbiota composition were analyzed. RESULTS: Severe impairment of respiratory function was observed in the mice sensitized by the nasal and cutaneous paths. It was associated with epithelial dysfunction characterized by an increased permeability secondary to junction protein disruption. Such sensitization paths induced a mixed eosinophilic and neutrophilic inflammatory response with high interleukin (IL)-17 airway secretion. In contrast, orally sensitized mice showed a mild impairment of respiratory function. Epithelial dysfunction was mild with increased mucus production, but preserved epithelial junctions. Regarding lung microbiota, sensitization provoked a significant loss of diversity. At the genus level, Cutibacterium, Acinetobacter, Streptococcus and Lactobacillus were found to be modulated according to the sensitization pathway. An increase in theanti-inflammatory microbiota metabolites was observed in the oral-sensitization group. CONCLUSIONS: Our study highlights the strong impact of the sensitization route on the pathophysiology and the critical phenotypic diversity of allergic asthma in a mouse model.

Obesity-Induced Memory Deficits in Female Rats Are Oestrous Cycle Dependent and Linked to Impaired Brain Kynurenine Pathway Metabolism.

INTRODUCTION: Obesity is associated with impaired learning, but the mechanisms underlying this cognitive dysfunction are poorly understood. Moreover, whether obesity-induced learning deficits show sexual dimorphism remains controversial. Females are believed to be protected from cognitive decline by oestrogens. These hormones enhance the expression of tryptophan hydroxylase 2, the rate-limiting enzyme in the transformation of tryptophan (Trp) into serotonin which plays a significant role in learning and memory. However, several learning-regulating compounds also arise from Trp metabolism through the kynurenine pathway (KP), including kynurenic acid (KA), xanthurenic acid (XA), and NAD+. The present study aimed to determine the involvement of the KP of Trp metabolism in the regulation of learning in control and obese female rats. METHODS: The learning capabilities of control and obese rats were evaluated using the novel object recognition test. Trp and Trp-derived metabolites were quantified in the hippocampus and frontal cortex by ultra-performance liquid chromatography-tandem mass spectrometry. RESULTS: Control rats in proestrus/oestrous performed better than their control mates in metestrus/dioestrus. Likewise, while control and obese rats in dioestrus/metestrus did not show differences in learning, obese rats in proestrus/oestrous displayed decreased memory capacity along with decreased Trp concentration and reduced KA, XA, and NAD+ production in the hippocampus. These neurochemical alterations were associated with impaired expression of mRNAs coding for key enzymes of the KP. CONCLUSION: The results presented here indicate that the deleterious effects of obesity on learning are closely related to the oestrous cycle and associated with an impairment of the KP of Trp metabolism.

Identification of 8-Hydroxyquinoline Derivatives That Decrease Cystathionine Beta Synthase (CBS) Activity.

CBS encodes a pyridoxal 5'-phosphate-dependent enzyme that catalyses the condensation of homocysteine and serine to form cystathionine. Due to its implication in some cancers and in the cognitive pathophysiology of Down syndrome, the identification of pharmacological inhibitors of this enzyme is urgently required. However, thus far, attempts to identify such molecules have only led to the identification of compounds with low potency and limited selectivity. We consequently developed an original, yeast-based screening method that identified three FDA-approved drugs of the 8-hydroxyquinoline family: clioquinol, chloroxine and nitroxoline. These molecules reduce CBS enzymatic activity in different cellular models, proving that the molecular mechanisms involved in yeast phenotypic rescue are conserved in mammalian cells. A combination of genetic and chemical biology approaches also revealed the importance of copper and zinc intracellular levels in the regulation of CBS enzymatic activity-copper promoting CBS activity and zinc inhibiting its activity. Taken together, these results indicate that our effective screening approach identified three new potent CBS inhibitors and provides new findings for the regulation of CBS activity, which is crucial to develop new therapies for CBS-related human disorders.

Perinatal Administration of C-Phycocyanin Protects Against Atherosclerosis in apoE-Deficient Mice by Modulating Cholesterol and Trimethylamine-N-Oxide Metabolisms.

OBJECTIVE: Gestational hypercholesterolemia concomitantly with a highly oxidative environment is associated with higher atherosclerosis in human and animal offspring. This work aimed to determine whether perinatal administration of a C-phycocyanin concentrate, a powerful antioxidant, can protect against atherosclerosis development in genetically hypercholesterolemic mice in adult life. Approach and Results: C-Phycocyanin was administered during gestation solely or gestation and lactation to apolipoprotein E-deficient mice. Male and female offspring were studied until 25 weeks old. Progenies born to supplemented mothers displayed significantly less atherosclerotic root lesions than control group in all groups excepted in male supplemented during gestation and lactation. Female born to supplemented mothers had a greater gallbladder total bile acid pool, lower secondary hydrophobic bile acid levels such as lithocholic acid, associated with less plasma trimethylamine N-oxide at 16 weeks old compared with control mice. Regarding male born to C-Phycocyanin administrated mothers, they expressed a higher high-density lipoprotein cholesterol level, more soluble bile acids such as ß-muricholic acids, and a decreased plasma trimethylamine at 16 weeks old. Liver reduced-to-oxidized glutathione ratio were increased and liver gene expression of superoxide dismutase and glutathione peroxidase were significantly decreased in male born to gestational supplemented mothers. No difference in the composition of cecal microbiota was found between groups, regardless of sex. CONCLUSIONS: Our findings suggest a protective effect of perinatal antioxidant administration on atherosclerosis development in apolipoprotein E-deficient mice involving sex-specific mechanisms.