0000000000146338
AUTHOR
Souleymane Abdoul-azize
Unvolvement of calcium signaling and MAP kinases in lipid taste perception
In this work, we demonstrate that stromal interaction molecule 1 (STIM1), a sensor of Ca2+ depletion in the endoplasmic reticulum, mediates fatty acid–induced Ca2+ signaling in the mouse tongue and fat preference. We showed that linoleic acid (LA) induced the production of arachidonic acid (AA) and lysophosphatidylcholine (Lyso-PC) by activating multiple phospholipase A2 isoforms via CD36. This activation triggered Ca2+ influx in lingual CD36-positive taste bud cells (TBCs) purified from mouse CVP. LA also induced the production of Ca2+ influx factor (CIF). STIM1 was found to regulate LA-induced CIF production and the opening of store-operated Ca2+ (SOC) channels. Furthermore, CD36-positive…
ERK1/2 activation in human taste bud cells regulates fatty acid signaling and gustatory perception of fat in mice and humans
Obesity is a major public health problem. An in-depth knowledge of the molecular mechanisms of oro-sensory detection of dietary lipids may help fight it. Humans and rodents can detect fatty acids via lipido-receptors, such as CD36 and GPR120. We studied the implication of the MAPK pathways, in particular, ERK1/2, in the gustatory detection of fatty acids. Linoleic acid, a dietary fatty acid, induced via CD36 the phosphorylation of MEK1/2-ERK1/2-ETS-like transcription factor-1 cascade, which requires Fyn-Src kinase and lipid rafts in human taste bud cells (TBCs). ERK1/2 cascade was activated by Ca2+ signaling via opening of the calcium-homeostasis modulator-1 (CALHM1) channel. Furthermore, f…
Effects of Zizyphus lotus L. (Desf.) polyphenols on Jurkat cell signaling and proliferation.
We assessed the effects of Zizyphus lotus L. (Desf.) polyphenols (ZLP) on T-cell signaling and proliferation. Our results showed that ZLP exerted no effect on the increases in intracellular free calcium concentrations, [Ca(2+)]i, in human Jurkat T-cells. However, ZLP modulated the thapsigargin-induced increases in [Ca(2+)]i in these cells. ZLP treatment was found to decrease the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). In addition, ZLP induced a rapid (t1/2=33s) and dose-dependent decrease in intracellular pH (pHi) in human Jurkat T-cells. Furthermore, ZLP significantly curtailed T-cell proliferation by diminishing their progression from S to G2/M phase of cell…
Obesity alters the gustatory perception of lipids in the mouse: plausible involvement of lingual CD36. : Obesity decreases the fat preference
International audience; A relationship between orosensory detection of dietary lipids, regulation of fat intake, and body mass index was recently suggested. However, involved mechanisms are poorly understood. Moreover, whether obesity can directly modulate preference for fatty foods remains unknown. To address this question, exploration of the oral lipid sensing system was undertaken in diet-induced obese (DIO) mice. By using a combination of biochemical, physiological, and behavioral approaches, we found that i) the attraction for lipids is decreased in obese mice, ii) this behavioral change has an orosensory origin, iii) it is reversed in calorie-restricted DIO mice, revealing an inverse …
STIM1, CD36 lingual et perception gustative lipidique
> Selon l’Organisation mondiale de la sante (OMS) [1], l’obesite atteint des proportions epidemiques dans le monde, avec plus de 1,6 milliards d’adultes en surpoids et au moins 500 millions de personnes cliniquement obeses. Globalement, un adulte sur dix est obese dans le monde. Cette situation a des consequences importantes en termes de sante publique. En effet, l’obesite, particulierement l’obesite viscerale, est un facteur de risque de pathologies telles que le diabete de type II, les atteintes cardiovasculaires, l’hypertension et certaines formes de cancers [2]. Bien qu’il existe un determinisme genetique, les facteurs environnementaux dont l’alimentation jouent un role important dans l…
Ca2+ signaling in taste bud cells and spontaneous preference for fat: Unresolved roles of CD36 and GPR120
Recent compelling evidences from rodent and human studies raise the possibility for an additional sixth taste modality devoted to oro-gustatory perception of dietary lipids. Understanding the mechanisms underlying oro-gustatory detection of dietary fat is critical for the prevention and treatment of obesity. A number of studies have suggested that lingual CD36, a glycoprotein, highly expressed by circumvallate papillae of the tongue, is implicated in the perception of dietary fat taste. G protein-coupled receptors (GPCRs) are important signaling molecules for many aspects of cellular functions. It has been shown that these receptors, particularly GPR120, are also involved in lipid taste per…
Eicosapentaenoic acid modulates fatty acid metabolism and inflammation in Psammomys obesus.
Abstract The desert gerbil, Psammomys obesus, is a unique polygenic animal model of metabolic syndrome (insulin resistance, obesity and type 2 diabetes), and these pathological conditions resemble to those in human beings. In this study, the animals were fed ad libitum either a natural diet (ND) which contained desertic halophile plants or a standard laboratory diet (STD) or a diet which contained eicosapentaenoic acid (EPA), hence, termed as EPA diet (EPAD). In EPAD, 50% of total lipid content was replaced by EPA oil. By employing real-time PCR, we assessed liver expression of key genes involved in fatty acid metabolism such as PPAR-α, SREBP-1c, LXR-α and CHREBP. We also studied the expres…
Oro-gustatory perception of dietary lipids and calcium signaling in taste bud cells are altered in nutritionally obesity-prone Psammomys obesus.
Since the increasing prevalence of obesity is one of the major health problems of the modern era, understanding the mechanisms of oro-gustatory detection of dietary fat is critical for the prevention and treatment of obesity. We have conducted the present study on Psammomys obesus, the rodent desert gerbil which is a unique polygenic natural animal model of obesity. Our results show that obese animals exhibit a strong preference for lipid solutions in a two-bottle test. Interestingly, the expression of CD36, a lipido-receptor, in taste buds cells (TBC), isolated from circumvallate papillae, was decreased at mRNA level, but remained unaltered at protein level, in obese animals. We further st…
Diacylglycerol-containing oleic acid induces increases in [Ca(2+)](i) via TRPC3/6 channels in human T-cells.
Though most of the studies have focused on the effects of free fatty acids on T-cell activation, fatty acids incorporated into plasma membrane phospholipids may also affect cell signaling via diacylglycerol (DAG), generally produced by phospholipid hydrolysis. In the present study, we have synthesized a DAG-containing oleic acid and studied its implication in the modulation of calcium signaling in human Jurkat T-cells. 1-palmitoyl-2-oleoyl-sn-glycerol (POG) induced a dose-dependent increase in [Ca(2+)](i). This effect was due to the presence of oleic acid at the sn-2 position as no differences were observed between POG and 1-stearoly-2-oleoyl-sn-glycerol (SOG). However, the substitution of …
Effects of polyphenols and lipids from Pennisetum glaucum grains on T-cell activation: modulation of Ca2+ and ERK1/ERK2 signaling
International audience; BACKGROUND: Pearl millet (PM), i.e., Pennisetum glaucum, is widely grown in Africa and known for its anti-oxidant and anti-hyperlipidemic properties.METHODS: The P. glaucum grains were obtained from the region of Ouled Aïssa (South of Algeria). We assessed the effects of phenolic compounds and lipids, extracted from seeds of P. glaucum, on rat lymphocyte proliferation, activated by phorbol 12-myristate 13-acetate and ionomycin. In order to explore signaling pathway, triggered by these compounds, we assessed interleukin-2 (IL-2) mRNA expression and extracellular signal-regulated kinase-1/2 (ERK1/ERK2) phosphorylation. Finally, we determined increases in free intracell…