A molecular dynamics approach to explore the structural characterization of cataract causing mutation R58H on human γD crystallin

Adequate placental angiogenesis is critical for the establishment of the placental circulation and thus for normal feto-placental growth and development. Fatty acid-binding protein-4 (FABP4) plays a pro-angiogenic role in endothelial cells; however, very little information is available in placental first trimester trophoblast cells. Here we report that exogenously added FABP4 (exo-FABP4) stimulated tube formation (as a measure of in vitro angiogenesis) in HTR8/SVneo trophoblastic cells. HTR-8/SVneo cells were incubated in the presence of exogenously added FABP4 at different concentrations and time points. Cellular growth, proliferation, in vitro tube formation, expression of growth stimulatory-, fatty acid transporters, and angiogenic genes were investigated. Internalization of exo-FABP4 was carried out using immunocytochemistry. Radioactive fatty acid uptake was determined in the presence and absence of FABP4 metabolic inhibitor. Exo-FABP4 (10–100 ng/ml) stimulated proliferation of HTR8/SVneo cells as compared to control. Exo-FABP4 dose dependently increased growth and viability of the cells to the similar extent as done by 50 µM of arachidonic acid. Exo-FABP4-induced tube formation and proliferation were significantly inhibited by FABP4 (BMS309403) inhibitor. Exo-FABP4 stimulated the expression of growth stimulatory genes such as tissue inhibitor of matrix metalloproteinases-1 (TIMP1), insulin-like growth factor 1 (IGF1), and also prokineticin 2 (PROK2), the pro-angiogenic mediators in these cells. In addition, expressions of genes associated with proliferation and differentiation such as sonic hedgehog (SHH) and WNT1 inducible signalling pathway protein 1 (WISP1) were significantly expressed when cells were exposed to exo-FABP4. Our findings reveal a pro-angiogenic role of FABP4 in first trimester placental trophoblast cells and its regulation may have impact in placental physiology.     

Fatty acid-induced angiogenesis in first trimester placental trophoblast cells: Possible roles of cellular fatty acid-binding proteins

Angiogenesis is involved in the growth of new blood vessels from the existing one. Consequently, angiogenesis plays an indispensable role in tissue growth and repair including early placentation processes. Besides angiogenic growth factors (vascular endothelial growth factor (VEGF), angiopoietin-like 4 (ANGPTL4), placental growth factor (PlGF), platelet derived growth factor (PDGF), fibroblast growth factors (FGF)), dietary fatty acids (c>16) also directly or indirectly modulate angiogenic processes in tumors and other cell systems. Usually n − 3 fatty acids inhibit whereas n − 6 fatty acids stimulate angiogenesis in tumors and other cells. Contrary to this, docosahexaenoic acid, 22:6n − 3 (DHA) and other fatty acids including conjugated linoleic acid stimulate angiogenesis in placental first trimester cells. In addition to the stimulation of expression of major angiogenic factors such as VEGF and ANGPTL4, fatty acids also stimulate expression of intracellular fatty acid-binding proteins (FABPs) FABP-4 and FABP-3 those are known to directly modulate angiogenesis. Emerging data indicate that FABPs may be involved in the angiogenesis process. This paper reviews the fatty acid mediated angiogenesis process and the involvement of their binding proteins in these processes.     

Fatty acid uptake by breast cancer cells (MDA-MB-231): Effects of insulin,leptin, adiponectin,and TNFα

In order to exert metabolic effects, fatty acids must be taken up by cells and metabolize effectively to different classes of cellular lipids (triacylglycerols, phospholipids, etc.) for incorporation into different cellular and intracellular compartments. Therefore, the main aim of the present study is to investigate the uptake and metabolism of fatty acids representing three different series of fatty acids such as oleic acid, 18:1n-9 (OA), arachidonic acid, 20:4n-6 (AA), and eicosapentaneoic acid, 20:5n-3 (EPA) by breast cancer cells, MDA-MB-231. Moreover, we investigated the effects of insulin and several adipokines on the fatty acid uptake by these cells as obesity and insulin resistance syndrome have been suggested to affect breast cancer risk. We report for the first time that AA was predominantly taken up by these cells compared with EPA and OA. Pre-incubation of these cells with TNFα stimulated most of the uptake of EPA (30%), whereas uptake of OA and AA was stimulated only 10–15% compared with the controls. Insulin, leptin, and adiponectin had no effect on fatty acid uptake by these cells. Together these results demonstrate that preferential uptake of AA in MDA-MB-231 cells, and the fatty acid uptake activity of these cells is influenced by TNFα.     

cis-9,trans-11 conjugated linoleic acid stimulates expression of angiopoietin like-4 in the placental extravillous trophoblast cells

A number of studies have been carried out to examine the biological function of conjugated linoleic acid (CLA) and its potential health benefits. However, not much is known about how CLA isomers mediate their effect on angiogenesis and vascularization during early placentation. In this paper we demonstrate that cis-9,trans-11(c9,t11)-CLA stimulated the expression of angiopoietin like-4 (ANGPTL4) mRNA and protein accompanied by tube formation in first trimester placental trophoblast cells, HTR8/SVneo whereas the other CLA isomer, trans-10,cis-12 (t10,c12)-CLA had no such effects. c9,t11-CLA however did not stimulate expression of the most potent angiogenic factor, vascular endothelial growth factor (VEGF) in these cells. Silencing ANGPTL4 in these cells significantly reduced the stimulatory effect of c9,t11-CLA on tube formation, indicating the involvement of ANGPTL4. In addition, c9,t11-CLA increased the mRNA expression of several pro-angiogenic factors such as fatty acid binding protein-4 (FABP4), cyclooxygenase-2 (COX-2) and adipose differentiation-related protein (ADRP) in HTR8/SVneo cells. c9,t11-CLA also induced the uptake of docosahexaenoic acid, 22:6n − 3 (DHA), a stimulator of tube formation in these cells. Triacsin C, an acylCoA synthetase inhibitor, attenuated c9,t11-CLA induced DHA uptake, tube formation and cellular proliferation in HTR8/SVneo cells.     

Preferential distribution of long chain polyunsaturated fatty acids in phospatidyl ethanolamine fraction of guinea pig alveolar apical membranes

We investigated the fatty acid distribution in guinea pig alveolar apical membranes at different developmental stages. Fatty acid composition of the purified membranes isolated from guinea pig fetuses (at 65 day, term=68 day), neonates (day 1) and adult males was determined. The levels of arachidonic acid (AA) and docosahexaenoic acid (DHA) were higher in the adult guinea pig alveolar apical membrane phosphatidylethanolamine (PE) fraction (9. 3+/-2.2 and 2.9+/-1.0%, respectively) while in other phospholipids (PL) fractions their levels were low or absent (P<0.01). Furthermore, levels of AA and DHA in the PE fraction of apical membrane increased significantly from fetal (6.6+/-3.0 and 0.8+/-0.4%, respectively) to neonatal life (10.3+/-1.5 and 3.0+/-0.8%, respectively). Increase in the level of DHA (almost four-fold) was much more pronounced than that of AA (P<0.05). As for guinea pig alveolar membranes, EPA and AA were mostly present in the PE fraction in pulmonary adenocarcinoma derived cells (A549 cells), a parallel model of type II pneumocytes, with the levels of AA around three-fold greater than that of EPA, Binding of radiolabelled fatty acids to A549 cells showed no significant differences between the maximum uptake achieved for different fatty acids (AA, 1.7+/-0.2, EPA, 2.3+/-0.3, LA, 1.7+/-0.2, OA, 2.0+/-0.2nmol/mg protein, P>0.5). Once the fatty acids were taken up by these cells AA was mostly identifiable in the monoacylglycerol (MAG) fraction, whereas EPA was equally distributed between the MAG and PL fractions. Oleic acid was mainly present in the triglyceride (TAG) fraction whereas LA was evenly distributed between the TAG, MAG, and PL fractions. Our data demonstrate a preferential distribution of AA and DHA in PE fractions of alveolar apical membranes during development.     

Effects of fatty acid unsaturation numbers on membrane fluidity and α-secretase-dependent amyloid precursor protein processing

Fatty acids may integrate into cell membranes to change physical properties of cell membranes, and subsequently alter cell functions in an unsaturation number-dependent manner. To address the roles of fatty acid unsaturation numbers in cellular pathways of Alzheimer's disease (AD), we systematically investigated the effects of fatty acids on cell membrane fluidity and α-secretase-cleaved soluble amyloid precursor protein (sAPP(α)) secretion in relation to unsaturation numbers using stearic acid (SA, 18:0), oleic acid (OA, 18:1), linoleic acid (LA, 18:2), α-linolenic acid (ALA, 18:3), arachidonic acid (AA, 20:4), eicosapentaenoic acid (EPA, 20:5), and docosahexaenoic acid (DHA, 22:6). Treatments of differentiated human neuroblastoma (SH-SY5Y cells) with AA, EPA and DHA for 24h increased sAPP(α) secretion and membrane fluidity, whereas those treatments with SA, OA, LA and ALA did not. Treatments with AA and DHA did not alter the total expressions of amyloid precursor protein (APP) and α-secretases in SH-SY5Y cells. These results suggested that not all unsaturated fatty acids but only those with 4 or more double bonds, such as AA, EPA and DHA, are able to increase membrane fluidity and lead to increase in sAPP(α) secretion. This study provides insights into dietary strategies for the prevention of AD.     

Eicosapentaenoic acid (20:5 n-3) increases fatty acid and glucose uptake in cultured human skeletal muscle cells

This study was conducted to evaluate the chronic effects of eicosapentaenoic acid (EPA) on fatty acid and glucose metabolism in human skeletal muscle cells. Uptake of [14C]oleate was increased >2-fold after preincubation of myotubes with 0.6 mM EPA for 24 h, and incorporation into various lipid classes showed that cellular triacylgycerol (TAG) and phospholipids were increased 2- to 3-fold compared with control cells. After exposure to oleic acid (OA), TAG was increased 2-fold. Insulin (100 nM) further increased the incorporation of [14C]oleate into all lipid classes for EPA-treated myotubes. Fatty acid beta-oxidation was unchanged, and complete oxidation (CO2) decreased in EPA-treated cells. Basal glucose transport and oxidation (CO2) were increased 2-fold after EPA, and insulin (100 nM) stimulated glucose transport and oxidation similarly in control and EPA-treated myotubes, whereas these responses to insulin were abolished after OA treatment. Lower concentrations of EPA (0.1 mM) also increased fatty acid and glucose uptake. CD36/FAT (fatty acid transporter) mRNA expression was increased after EPA and OA treatment compared with control cells. Moreover, GLUT1 expression was increased 2.5-fold by EPA, whereas GLUT4 expression was unchanged, and activities of the mitogen-activated protein kinase p38 and extracellular signal-regulated kinase were decreased after treatment with OA compared with EPA. Together, our data show that chronic exposure of myotubes to EPA promotes increased uptake and oxidation of glucose despite a markedly increased fatty acid uptake and synthesis of complex lipids.     

Curcumin stimulates angiogenesis through VEGF and expression of HLA‐G in first‐trimester human placental trophoblasts

Curcumin has a protective role in placental diseases like preeclampsia and preterm birth. Very little is known about its functional effects on growth, angiogenesis, and epigenetic activities of human first trimester placenta. HTR8/SVneo trophoblasts cells were used as model for human first trimester placenta. Effects of curcumin (≥80%) in these cells were investigated using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT), radioactive thymidine uptake, quantitative real‐time polymerase chain reaction (qRT‐PCR), promoter DNA methylation, qRT‐PCR array, tube formation, wound healing, and immunoblot assays. PC3 (prostate cancer), JEG‐3 (trophoblast), and HMEC‐1 (endothelial) cells were used as control in various experiments. Unlike in PC3 cells, curcumin stimulated growth, proliferation, and viability in HTR8/SVneo cells. Curcumin increased tube formation, and messenger RNA (mRNA) expression of angiogenic factors such as vascular endothelial growth factor A (VEGFA) and protein expression of proangiogenic factor VEGF receptor‐2 and fatty acid‐binding protein‐4 (FABP4) in these cells. Curcumin‐stimulated tube formation was associated with an increased expression of VEGFR2 and FABP4. The stimulatory effects of curcumin were inhibited by VEGFR2 (SU5416) and FABP4 (BMS309403) inhibitors. Curcumin also significantly increased both mRNA and protein expression of HLA‐G in HTR8/SVneo cells. Curcumin increased mRNA expression of DNMT3A and NOTCH signaling system whereas down‐regulated mRNA expression of HSD11β2. Curcumin enhanced hypomethylation of gene promoters against oxidative stress and DNA damage pathway mediators. Curcumin promotes cell growth, migration, and thus angiogenic potential of these cells. Increased expression of HLA‐G by curcumin, hitherto unknown, is a novel finding since HLA‐G not only favors the immune environment for invasive trophoblasts but also positively modulates angiogenesis.     

Expression of rat L-FABP in mouse fibroblasts: role in fat absorption

Fatty acid-binding proteins (FABP) are abundant cytosolic proteins whose level is responsive to nutritional, endocrine, and a variety of pathological states. Although FABPs have been investigatedin vitro for several decades, little is known of their physiological function. Liver L-FABP binds both fatty acids and cholesterol. Competitive binding analysis and molecular modeling studies of L-FABP indicate the presence of two ligand binding pockets that accomodate one fatty acid each. One fatty acid binding site is identical to the cholesterol binding site. To test whether these observations obtainedin vitro were physiologically relevant, the cDNA encoding L-FABP was transfected into L-cells, a cell line with very low endogenous FABP and sterol carrier proteins. Uptake of both ligands did not differ between control cells and low expression clones. In contrast, both fatty acid uptake and cholesterol uptake were stimulated in the high expression cells. In high expression cells, uptake of fluorescent cis-parinaric acid was enhanced more than that of trans-parinaric acid. This is consistent with the preferential binding of cis-fatty acids to L-FABP but in contrast to the preferential binding of trans-parinaric acid to the L-cell plasma membrane fatty acid transporter (PMFABP). These data show that the level of cytosolic fatty acids in intact cells can regulate both the extent and specificity of fatty acid uptake. Last, sphingomyelinase treatment of L-cells released cholesterol from the plasma membrane to the cytoplasm and stimulated microsomal acyl-CoA: cholesteryl acyl transferase (ACAT). This process was accelerated in high expression cells. These observations show for the first time in intact cells that L-FABP, a protein most prevalent in liver and intestine where much fat absorption takes place, may have a role in fatty acid and cholesterol absorption.Abbreviations FABP fatty acid-binding protein - L-FABP liver fatty acid-binding protein - I-FABP intestinal fatty acid-binding protein - H-FABP heart fatty acid-binding protein - A-FABP adipocyte fatty acid-binding protein - PMFABP plasma membrane fatty acid-binding protein - SCP-2 sterol carrier protein-2 - Dehydroergosterol (DHE) d-5,7,9(11),22-ergostatetraene-3b-ol - cis-parinaric acid-9Z, 11E, 13E, 15Z-octatetraenoic acid - trans parinaric acid, 9E, 11E, 13E, 14E-octatetraenoic acid - BSA bovine serum albumin - KRH Krebs-Ringer-Henseleit buffer     

Expression of cFABP and PPAR in trophoblast cells: effect of PPAR ligands on linoleic acid uptake and differentiation

Throughout gestation, fetal growth depends, in part, on placental transfer of maternal essential fatty acid (EFA) and long-chain polyunsaturated fatty acid. All fatty acid (FA) can cross lipid bilayer by simple diffusion, such as those in the syncytiotrophoblasts, the multinucleated, terminally differentiated trophoblast cells. The trophoblasts differentiation process is accompanied by an increase of human chorionic gonadotropin (hCG) secretion and an inhibition of Human Achaete-Scute Homologue-2 expression (Hash-2). Furthermore, a number of FA-binding proteins (FABPs) have been identified in membrane and cytoplasm of mammalian cells, which are thought to facilitate the transfer of FA across membranes and their intracellular channeling. Thus, the aim of this study was to investigate the implication of cFABPs in linoleic acid (LA) uptake by human trophoblast cells according to differentiation. Moreover, since peroxisome proliferator-activated receptor (PPARs) regulate the expression of cFABP and play an important role in trophoblast cells differentiation, the effects of PPARs ligands are verified on cFABP expression and differentiation. Herein, we reported the increase of the expression of liver and heart FABP (L- and H-FABP) upon differentiation of trophoblast cells, an inhibition of PPAR alpha and beta, while PPAR gamma levels remains unchanged. The nonselective peroxisome-proliferating agents, bezafibrate and LA, impaired trophoblast differentiation, and reduced L- and H-FABP expression. Furthermore, cobalt, a chemical agent known to mimic hypoxia, inhibits trophoblast cells differentiation and diminishes H-, L-FABP and PPARs expression. Finally, both treatments show no influence on LA uptake by trophoblast cells. In conclusion, this study showed that there is no correlation between the expression of H- and L-FABP and LA uptake by trophoblast cells and that bezafibrate and LA greatly impaired trophoblast cells differentiation.     

Real-Time Tracking of BODIPY-C12 Long-Chain Fatty Acid in Human Term Placenta Reveals Unique Lipid Dynamics in Cytotrophoblast Cells

While the human placenta must provide selected long-chain fatty acids to support the developing fetal brain, little is known about the mechanisms underlying the transport process. We tracked the movement of the fluorescently labeled long-chain fatty acid analogue, BODIPY-C₁₂, across the cell layers of living explants of human term placenta. Although all layers took up the fatty acid, rapid esterification of long-chain fatty acids and incorporation into lipid droplets was exclusive to the inner layer cytotrophoblast cells rather than the expected outer syncytiotrophoblast layer. Cytotrophoblast is a progenitor cell layer previously relegated to a repair role. As isolated cytotrophoblasts differentiated into syncytialized cells in culture, they weakened their lipid processing capacity. Syncytializing cells suppress previously active genes that regulate fatty-acid uptake (SLC27A2/FATP2, FABP4, ACSL5) and lipid metabolism (GPAT3, LPCAT3). We speculate that cytotrophoblast performs a previously unrecognized role in regulating placental fatty acid uptake and metabolism.     

Uptake and distribution of cis-unsaturated fatty acids and their effect on free radical generation in normal and tumor cells in vitro

We have previously shown that cis-unsaturated fatty acids (c-UFAs) possess a selective tumoricidal action that can be blocked by antioxidants. This property of c-UFAs might be due to various factors, including increased uptake, unusual distribution, or an ability to alter free radical generation in tumor but not normal cells. 14C-labelled linoleic acid (LA) uptake was almost the same in normal and tumor cells, whereas that of 14C-labelled arachidonic acid (AA) and 14C-labelled eicosapentaenoic acid (EPA) in tumor cells was substantially less than in normal cells. Tumor cells incorporate major portions of the fatty acids in the ether lipid and phospholipid fractions, whereas normal cells incorporate the fatty acids primarily in the phospholipid fraction. LA, AA, and EPA augmented nitroblue tetrazolium reduction, an indication of free radical generation, selectively in the tumor cells. These results suggest that there are significant differences between normal and tumor cells in fatty acid uptake and distribution, and in the ability of fatty acids to generate free radicals.     

Maternal eicosapentaenoic acid feeding promotes placental angiogenesis through a Sirtuin-1 independent inflammatory pathway

Maternal overnutrition or obesity is associated with a wide range of metabolic disorders and may impair placental angiogenesis. Previous studies have shown that n-3 polyunsaturated fatty acids (PUFA) promote fetal growth in both rodents and humans. Whether n-3 PUFA impacts on placental angiogenesis in vivo remains unclear. Sirtuin-1 (SIRT1) is a protein deacetylase that plays an important role in regulating inflammation and endothelial function. Little information is available on a putative role of SIRT1 in placental angiogenesis. The goal of this study was to examine the capability of eicosapentaenoic acid (EPA) to regulate angiogenesis and inflammation in SIRT1-deficient placentas. In the present study, male and female SIRT1^+/− mice were mated overnight, then primiparous SIRT1^+/− mice were fed a 60% kcal HFD or equienergy EPA diet (4.4% EPA-ethyl ester). We found that the EPA diet significantly improved maternal insulin sensitivity and decreased plasma levels of inflammatory factors IL-6 and TNFα concentration. Moreover, EPA treatment promoted fetus growth and placental angiogenesis, and inhibited the hypoxia inducible factor-1α(HIF1α) pathway. SIRT1 deficiency exhibited an opposite effect, leading to decrease in placental angiogenesis and fetal weight. No significant effect was observed between diet and genotype. Here, we reported for the first time that EPA treatment increased the expression of placental inflammatory genes and promoted translocation of NFκB into the nucleus. On the contrary, SIRT1-deficient placentas showed a decreased inflammation state. Together, these data demonstrate a previously unknown role of EPA to promote placental angiogenesis through a SIRT1 independent inflammatory pathway.     

Cellular interactions between n-6 and n-3 fatty acids: a mass analysis of fatty acid elongation/desaturation, distribution among complex lipids, and conversion to eicosanoids.

The biologic effect of eicosanoids depends in large measure upon the relative masses in tissues of eicosanoids derived from the n-6 fatty acids, dihomogammalinolenic acid and arachidonic acid, and the n-3 fatty acid, eicosapentaenoic acid. Generation of this tissue balance is related to the relative cellular masses of these precursor fatty acids, the competition between them for entry into and release from cellular phospholipids, and their competition for the enzymes that catalyze their conversion to eicosanoids. In order to better understand these processes, we studied the cellular interactions of n-6 and n-3 fatty acids using an essential fatty acid-deficient, PGE-producing, mouse fibrosarcoma cell line, EFD-1. Unlike studies using cells with endogenous pools of n-6 and n-3 fatty acids, the use of EFD-1 cells enabled us to examine the metabolic fate of each family of fatty acids both in the presence and in the absence of the second family of fatty acids. Thus, the specific effects of one fatty acid family on the other could be directly assessed. In addition, we were able to replete the cells with dihomogammalinolenic acid (DHLA), arachidonic acid (AA), and eicosapentaenoic acid (EPA) of known specific activities; thus the masses of cellular DHLA, AA, and EPA, and their metabolites, PGE1, PGE2, and PGE3, respectively, could be accurately quantitated. The major findings of this study were: 1) n-6 fatty acids markedly stimulated the elongation of EPA to 22:5 whereas n-3 fatty acids inhibited the delta 5 desaturation of DHLA to AA and the elongation of AA to 22:4; 2) n-6 fatty acids caused a specific redistribution of cellular EPA from phospholipid to triacylglycerol; 3) n-3 fatty acids reduced the mass of DHLA and AA only in phosphatidylinositol whereas n-6 fatty acids reduced the mass of EPA to a similar extent in all cellular phospholipids; and 4) n-3 fatty acids caused an identical (33%) reduction in the bradykinin-induced release of PGE1 and PGE2, whereas n-6 fatty acids stimulated PGE3 release 2.3-fold. Together, these highly quantitative metabolic data increase our understanding of the regulation of both the cellular levels of DHLA, AA, and EPA, and their availability for eicosanoid synthesis. In addition, these findings provide a context for the effective use of these fatty acids in dietary therapies directed at modulation of eicosanoid production.     

Relationship between fatty acid binding proteins,acetyl-CoA formation and fatty acid synthesis in developing human placenta

The relationship between fatty acid binding proteins, ATP citrate lyase activity and fatty acid synthesis in developing human placenta has been studied. Fatty acid binding proteins reverse the inhibitory efect of palmitoyl-CoA and oleate on ATP citrate lyase and fatty acid synthesis. In the absence of these inhibitors fatty acid binding proteins activate ATP citrate lyase and stimulate [ 1-¹⁴ C] acetate incorporation into placental fatty acids indicating binding of endogenous inhibitors by these proteins. Thus these proteins regulate the supply of acetyl-CoA as well as the synthesis of fatty acids from that substrates. As gestation proceeds and more lipids are required by the developing placenta fatty acid binding protein content, activity of ATP citrate lyase and rate of fatty acid synthesis increase indicating a cause and efect relationship between the demand of lipids and supply of precursor fatty acids during human placental development.     

FABP1 knockdown in human enterocytes impairs proliferation and alters lipid metabolism

Fatty Acid-Binding Proteins (FABPs) are abundant intracellular proteins that bind long chain fatty acids (FA) and have been related with inmunometabolic diseases. Intestinal epithelial cells express two isoforms of FABPs: liver FABP (LFABP or FABP1) and intestinal FABP (IFABP or FABP2). They are thought to be associated with intracellular dietary lipid transport and trafficking towards diverse cell fates. But still their specific functions are not well understood.To study FABP1's functions, we generated an FABP1 knockdown model in Caco-2 cell line by stable antisense cDNA transfection (FABP1as). In these cells FABP1 expression was reduced up to 87%. No compensatory increase in FABP2 was observed, strengthening the idea of differential functions of both isoforms. In differentiated FABP1as cells, apical administration of oleate showed a decrease in its initial uptake rate and in long term incorporation compared with control cells. FABP1 depletion also reduced basolateral oleate secretion. The secreted oleate distribution showed an increase in FA/triacylglyceride ratio compared to control cells, probably due to FABP1's role in chylomicron assembly. Interestingly, FABP1as cells exhibited a dramatic decrease in proliferation rate. A reduction in oleate uptake as well as a decrease in its incorporation into the phospholipid fraction was observed in proliferating cells.Overall, our studies indicate that FABP1 is essential for proper lipid metabolism in differentiated enterocytes, particularly concerning fatty acids uptake and its basolateral secretion. Moreover, we show that FABP1 is required for enterocyte proliferation, suggesting that it may contribute to intestinal homeostasis.     

Variations of lipid and fatty acid contents during the reproductive cycle of the anthozoan <Emphasis Type="Italic">Renilla koellikeri</Emphasis>

Lipid and fatty acid contents were monitored in the sea pansy Renilla koellikeri during its reproductive cycle. The fluctuations of lipids and fatty acids were closely related to sexual development and gonads represented the principal site of lipid storage in the colony. Between April and May, fatty acids and lipids greatly accumulated just prior to spawning. The subsequent decrease of lipid and fatty acid contents in June probably resulted from loss due to spawning. Fatty acid composition was assessed for the whole animal and was compared between male and female gonads, and between gonads and somatic tissues. Arachidonic acid (AA) was the principal fatty acid in the whole colony followed by palmitic acid and eicosapentaenoic acid (EPA). The examination of fatty acid variations in gonads showed that EPA and AA were highly incorporated in eggs during the month preceding spawning, whereas in the same period, EPA was the only fatty acid to accumulate in spermatophores. The differences of fatty acid levels observed in gonads reflected sex differences observed in colonies. The seasonal variations of the omega6/omega3 ratio of the colonies were largely influenced by EPA and AA, and appeared as a reliable indicator of the sexual maturity of the sea pansy.