Interaction of phenolic-fruit hallmarks and seasonal rhythms

Els animals estacionals realitzen variacions fisiològiques que els permeten adaptar-se als canvis ambientals anuals. Segons la teoria de la xenohormesi, els animals detecten senyals químics a les fruites per preparar-se per a la situació futura. En ser els(poli)fenols es produeixen en resposta a l'estrès; aquests podrien actuar com a senyals moleculars i les fruites podrien mostrar característiques fenòliques segons la temporada. L'objectiu d'aquesta tesi doctoral va ser dilucidar els efectes diferencials de característiques fenòliques específiques de la fruita en funció del fotoperíode. En primer lloc, es van investigar els efectes metabòlics de nous extractes estacionals enriquits amb (poli) fenols en rates F344 en diferents fotoperíodes. Alguns extractes van modular diversos marcadors metabolics de manera dependent del fotoperíode. En segon lloc aquests extractes de fruites es van estudiar en rates F344 subjectes a diferente probes metabòliques. Alguns extractes van contrarestar l'estat inflamatori depenent de l'estacionalitat de la fruita i el fotoperíode de consum, mentre que els efectes sobre el metabolisme dels lípids van ser independents de l'estacionalitat de la fruita. Finalment, es van testar dos tipus de cireres amb diferents característiques en rates F344.Los animales estacionales adaptan su fisiología a los cambios ambientales anuales. Los ritmos estacionales son guiados por señales externas, como el fotoperíodo y la nutrición. Las frutas ricas en (poli)fenoles son conocidas por sus beneficios para la salud. Según la teoría de la xenohormesis, los animales detectan señales químicas en las frutas para prepararse para la situación que se avecina. Los (poli)fenolesse producen en respuesta al estrés, y actúan como señales moleculares y las frutas mostrarían características fenólicas según las condiciones ambientales. El objetivo de la presente tesis doctoral fue dilucidar los efectos diferenciales de características fenólicas específicas de la fruta en función del fotoperiodo de consumo. En primer lugar, se investigaron los efectos metabólicos de nuevos extractos enriquecidos con (poli)fenoles de frutas estacionales en ratas F344 sanas expuestas a diferentes fotoperíodos. Algunos extractos modularon la glucemia y los niveles de circulantes de lípidos, de manera dependiente del fotoperíodo. En segundo lugar, estos extractos de frutas se estudiaron en ratas F344 sujetas a diferentes pruebas metabólicas para reproducir trastornos metabólicos.Seasonal animals have physiological and behavioural variations that allow them to adapt to annual environmental changes. To achieve optimal timing, seasonal rhythms need to be entrained by external cues, such as photoperiod and nutrition. Fruitsrich in (poly)phenols are known for their numerous health benefits. According to xenohormesis theory, animals sense chemical cues in fruits to prepare them for the upcoming situation. (Poly)phenols could act as molecular signals because these secondary metabolites are produced in response to stress; therefore, fruits show distinctive phenolic hallmarks depending on the environmental conditions. The aim of this PhD thesis was to elucidate the differential healthy effects of specific phenolic-fruit hallmarks depending on the photoperiod of consumption. First, metabolic effects of new phenolic-enriched extracts from seasonal fruits on healthy F344 rats exposed to different photoperiods were investigated. Some extracts modulated several biochemical markers, such as blood glucose and lipid levels, in a photoperiod-dependent manner. Second,these fruit extracts were studied in F344 rats subjected to metabolic challenge tests to mimick metabolic disorders

Photoperiod-Dependent Effects on Blood Biochemical Markers of Phenolic-Enriched Fruit Extracts

Fruits are rich in bioactive compounds, such as (poly)phenols, and their intake is associated with health benefits, although recent animal studies have suggested that the photoperiod of consumption influences their properties. Fruit loss and waste are critical issues that can be reduced by obtaining functional fruit extracts. Therefore, the aim of this study was to obtain phenolic-enriched extracts from eight seasonal fruits that can modulate blood biochemical parameters and to investigate whether their effects depend on the photoperiod of consumption. Eight ethanol-based extracts were obtained and characterized, and their effects were studied in F344 rats exposed to short (6 h light, L6) and long (18 h light) photoperiods. Cherry and apricot extracts decreased blood triacylglyceride levels only when consumed under the L6 photoperiod. Pomegranate, grape, and orange extracts reduced cholesterol and fasting glucose levels during the L6 photoperiod; however, plum extract reduced fasting glucose levels only during the L18 photoperiod. The results showed the importance of photoperiod consumption in the effectiveness of phenolic-enriched fruit extracts and promising evidence regarding the use of some of the developed fruit extracts as potential functional ingredients for the management of several blood biomarkers.Ministerio de Ciencia e Innovación (España)Depto. de Farmacia Galénica y Tecnología AlimentariaFac. de VeterinariaTRUEpu

DIETARY FIBRES REGULATE BILE ACID METABOLISM INDEPENDENT OF THE MICROBIOTA BY SUPPRESSING THE PRODUCTION OF SIGNALLING MOLECULE FGF15 IN THE ILEUM

Dietary fibres alter the microbiota and are linked to lower cholesterol levels. In the liver, bile acids are produced from cholesterol and excreted into the duodenum, where they enable lipid digestion. After reaching the ileum most bile acids are re-absorbed, and induce the expression of signalling molecule FGF19 (Fgf15 in mice). FGF15/19 travels to the liver where it inhibits CYP7A1, the rate-limiting enzyme in de novo bile acid synthesis. Here we investigated the effects of dietary fibres on bile acid metabolism in the small intestine and liver. Mice were fed a chow or a fibre-free diet (FFD) for up to 6 months. Some mice were treated with broad-spectrum antibiotics and a subset of mice on the FFD were supplemented with fructooligosaccharides (FOS) with or without antibiotics. Bile acids were measured using HPLC, gene expression was measured using Q-PCR and the microbiota was analysed using 16S sequencing.The expression of Fgf15 was increased on the FFD at all time points (3 days to 6 months), while the absorbance of bile acids, as measured by gene expression and bile acid secretion, was not changed during the early (up to 2 weeks) timepoints. Although we observed large differences in small intestinal microbiota between the diets, this did not cause the change in Fgf15 expression. Depleting the microbiota with antibiotics did not change the effect of the FFD on Fgf15. Supplementing mice on the FFD with FOS in their drinking water led to a decrease in Fgf15 expression, in both conventional and antibiotic treated mice. Cyp7a1 was consequently induced by the fibre-rich diets (chow and added FOS in drinking water).In conclusion, dietary fibres modulate the expression of Fgf15 independent of the microbiota and via this mechanism play an important role in bile acid and cholesterol homeostasis

Fatty acid metabolism in liver and muscle is strongly modulated by photoperiod in Fischer 344 rats

Circadian and seasonal variations produce variations in physiological processes throughout the day and the year, respectively. In this sense, both the light and the moment of feeding are strong modulators of the central and peripheral clocks. However, little is known about its influence on certain metabolic parameters and on the composition of liver and muscle fatty acids (FA). In the present study, 24 Fischer 344 rats were exposed for 11 weeks to different photoperiods, L6, L12 and L18, with 6, 12 and 18 h of light/day, respectively. They were fed a standard diet. Serum metabolic parameters, gene expression of liver enzymes and gastrocnemius muscle involved in the synthesis, elongation, desaturation and β-oxidation of FA were analyzed. We have found that exposure to different hours of light has a clear effect on FA composition and gene expression in the liver. Mainly, the biosynthesis of unsaturated FA was altered in the L18 animals with respect to those exposed to L12, while the L6 did not show significant changes. At the muscle level, differences were observed in the concentration of mono and polyunsaturated FA. A multivariate analysis confirmed the differences between L12 and L18 in a significant way. We conclude that exposure to long days produces changes in the composition of liver and muscle FA, as well as changes in the gene expression of oxidative enzymes compared to exposure to L12, which could be a consequence of different seasonal eating patterns.Fil: Ruiz de Azua, Maria Josefina. Departamento de Bioquimica y Biotecnologia ; Facultad de Quimica y Enologia ; Universitat Rovira I Virgili;Fil: Manocchio, Francesca. Departamento de Bioquimica y Biotecnologia ; Facultad de Quimica y Enologia ; Universitat Rovira I Virgili;Fil: Cruz Carrión, Álvaro. Departamento de Bioquimica y Biotecnologia ; Facultad de Quimica y Enologia ; Universitat Rovira I Virgili;Fil: Arola Arnal, Anna. Departamento de Bioquimica y Biotecnologia ; Facultad de Quimica y Enologia ; Universitat Rovira I Virgili;Fil: Torres Fuentes, Cristina. Departamento de Bioquimica y Biotecnologia ; Facultad de Quimica y Enologia ; Universitat Rovira I Virgili;Fil: Bernal, Claudio Adrian. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Ciencias Biológicas. Cátedra de Bromatología y Nutrición; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Sain, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Ciencias Biológicas. Cátedra de Bromatología y Nutrición; ArgentinaFil: Suarez, Manuel. Departamento de Bioquimica y Biotecnologia ; Facultad de Quimica y Enologia ; Universitat Rovira I Virgili

Characterization of two de novo KCNT1 mutations in children with malignant migrating partial seizures in infancy

The KCNT1 gene encodes for subunits contributing to the Na+-activated K+ current (KNa), expressed in many cell types. Mutations in KCNT1 have been found in patients affected with a wide spectrum of early-onset epilepsies, including Malignant Migrating Partial Seizures in Infancy (MMPSI), a severe early-onset epileptic encephalopathy characterized by pharmacoresistant focal seizures migrating from one brain region or hemisphere to another and neurodevelopment arrest or regression, resulting in profound disability. In the present study we report identification by whole exome sequencing (WES) of two de novo, heterozygous KCNT1 mutations (G288S and, not previously reported, M516V) in two unrelated MMPSI probands. Functional studies in a heterologous expression system revealed that channels formed by mutant KCNT1 subunits carried larger currents when compared to wild-type KCNT1 channels, both as homo- and heteromers with KCNT1 subunits. Both mutations induced a marked leftward shift in homomeric channel activation gating. Interestingly, the KCNT1 blockers quinidine (3-1000 μM) and bepridil (0.03-10 μM) inhibited in a concentration-dependent manner wild-type and mutant KCNT1 currents, with mutant channels showing higher sensitivity to blockade. This latter result suggests two genotype-tailored pharmacological strategies to specifically counteract the dysfunction of KCNT1 activating mutations in MMPSI affected patients