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The miR-200 family promotes the epithelial state by suppressing the Zeb1/Zeb2 epithelial gene transcriptional repressors. To identify other miR-200-regulated genes, we isolated mRNAs bound to transfected biotinylated miR-200c in mouse breast cancer cells. In all, 520 mRNAs were significantly enriched in miR-200c binding at least twofold. Putative miR-200-regulated genes included Zeb2 , enriched 3.5-fold in the pull down. However, Zeb2 knockdown does not fully recapitulate miR-200c overexpression, suggesting that regulating other miR-200 targets contributes to miR-200’s enhancement of epithelial gene expression. Candidate genes were highly enriched for miR-200c seed pairing in their 3′UTR and coding sequence and for genes that were downregulated by miR-200c overexpression. Epidermal growth factor receptor and downstream MAPK signaling pathways were the most enriched pathways. Genes whose products mediate transforming growth factor (TGF)-β signaling were also significantly overrepresented, and miR-200 counteracted the suppressive effects of TGF-β and bone morphogenic protein 2 (BMP-2) on epithelial gene expression. miR-200c regulated the 3′UTRs of 12 of 14 putative miR-200c-binding mRNAs tested. The extent of mRNA binding to miR-200c strongly correlated with gene suppression. Twelve targets of miR-200c ( Crtap, Fhod1, Smad2, Map3k1, Tob1, Ywhag/14-3-3γ, Ywhab/14-3-3β, Smad5, Zfp36, Xbp1, Mapk12 , Snail1 ) were experimentally validated by identifying their 3′UTR miR-200 recognition elements. Smad2 and Smad5 form a complex with Zeb2 and Ywhab/14-3-3β and Ywhag/14-3-3γ form a complex with Snail1. These complexes that repress transcription assemble on epithelial gene promoters. miR-200 overexpression induced RNA polymerase II localization and reduced Zeb2 and Snail1 binding to epithelial gene promoters. Expression of miR-200-resistant Smad5 modestly, but significantly, reduced epithelial gene induction by miR-200. miR-200 expression and Zeb2 knockdown are known to inhibit cell invasion in in vitro assays. Knockdown of each of three novel miR-200 target genes identified here, Smad5 , Ywhag and Crtap , also profoundly suppressed cell invasion. Thus, miR-200 suppresses TGF-β/BMP signaling, promotes epithelial gene expression and suppresses cell invasion by regulating a network of genes.

Some sea slugs are able to steal functional chloroplasts (kleptoplasts) from their algal food sources, but the role and relevance of photosynthesis to the animal host remain controversial. While some researchers claim that kleptoplasts are slowly digestible ‘snacks’, others advocate that they enhance the overall fitness of sea slugs much more profoundly. Our analysis shows light-dependent incorporation of 13 C and 15 N in the albumen gland and gonadal follicles of the sea slug Elysia timida , representing translocation of photosynthates to kleptoplast-free reproductive organs. Long-chain polyunsaturated fatty acids with reported roles in reproduction were produced in the sea slug cells using labelled precursors translocated from the kleptoplasts. Finally, we report reduced fecundity of E. timida by limiting kleptoplast photosynthesis. The present study indicates that photosynthesis enhances the reproductive fitness of kleptoplast-bearing sea slugs, confirming the biological relevance of this remarkable association between a metazoan and an algal-derived organelle.

Long-chain polyunsaturated fatty acids, n-3 series (n-3 LC-PUFA), are known for their preventive effects against cardiovascular disease. In an unfavourable economic and environmental context of fish oil production, marine microalgae could be an alternative source of n-3 LC-PUFA and are of interest for human nutrition. The aim of this study was to evaluate the effects of P. tricornutum, a microalga rich in eicosapentaenoic acid and used as a food supplement, on the metabolic disorders associated with metabolic syndrome and obesity development. Three male Wistar rat groups (n = 6) were submitted for eight weeks to a standard diet or high-fat diet (HF) with 10% fructose in drinking water, supplemented or not with 12% of P. tricornutum (HF-Phaeo). Supplementation led to n-3 LC-PUFA enrichment of lipids in the liver, plasma and erythrocytes. Plasma transaminases showed no difference between the HF and HF-Phaeo groups. Body weight, fat mass, inflammatory markers and insulinemia decreased in HF-Phaeo rats versus the HF group. Plasma total cholesterol, triacylglycerols and leptine diminished in HF-Phaeo rats, while HDL-cholesterol increased. In conclusion, this study highlights the beneficial effects of P. tricornutum in reducing the metabolic disorders associated with metabolic syndrome.

Non-alcoholic fatty liver disease represents the most common liver disease and is characterized by an excess of lipid accumulation in hepatocytes, mainly stored as triglycerides. Phaeodactylum tricornutum is a marine microalga, which is rich in bioactive molecules known to be hepatoprotective, such as n-3 long-chain polyunsaturated fatty acids and fucoxanthin. The aim of this study was to investigate the effects of a carotenoid extract from P. tricornutum in a cellular model of non-alcoholic fatty liver disease induced by palmitate treatment. The combined effects of carotenoids and lipids, especially n-3 long-chain polyunsaturated fatty acids, were also investigated by using a total lipophilic extract. HepG2 cells were exposed for 24 h to 250 µM palmitate with or without the addition of carotenoid extract (6 μg/mL) or total lipophilic extract (100 μg/mL). The addition of carotenoid extract or total lipophilic extract prevented the accumulation of triglycerides, total cholesterol and cholesterol esters. The carotenoid extract and total lipophilic extract also decreased the mRNA expression levels of genes involved in lipogenesis (ACACA, FASN, SCD and DGAT1) and cholesterol esterification (ACAT1/SOAT1). In addition, the total lipophilic extract also downregulated the LXR/NR1H3 and SREBF1 genes, which are involved in lipogenesis regulation. By contrast, the carotenoid extract increased the mRNA level of CPT1A, a β-oxidation related gene, and reduced the lipid droplet accumulation. In conclusion, this study highlights the preventive effects against non-alcoholic fatty liver disease of the two microalga extracts.

BackgroundMilk has a specific saturated fatty acid profile and its calcium content may change the kinetics of fat absorption.ObjectiveThe goal of this study was to compare the effect on LDL Cholesterol and other risk markers of four isolipidic diets differing by their fat food source, vegetable fat, spring milk fat, winter milk fat or winter milk fat supplemented with calcium, in healthy moderately hypercholesterolemic humans.Individuals and methodsThis double-blind, randomized trial with four parallel arms included 172 healthy adults with plasma LDL cholesterol (LDL-C) from 130 to 220 mg/dL and triglycerides below 300 mg/dL. Individual meal plans ensured a stable energy intake. In the three diets containing milk fat, milk fat provided 38% of energy. Vegetable fat and spring milk fat diets provided the same amount of saturated fatty acids while the winter milk fat diets were slightly richer in saturated fatty acids. Vegetable fat diet and winter milk fat diets provided the same amount of palmitic acid (7.0% EI), while the spring milk fat diet was slightly poorer in this fatty acid (5.1% EI). Cardiovascular risk markers were analyzed after 8 weeks of dietary intervention.ResultsThere was no significant difference in LDL-C and other markers, except total cholesterol (TC), apo C3 and CRP. TC was significantly higher with spring milk fat than with vegetable fat.ConclusionsIn this trial, the chosen vegetable fat did not have a significant beneficial effect on LDL-C compared to dairy fat. However, sub-group analysis showed differences in TC, apo C3 and CRP. These results need confirmation and long-term studies aiming at cardiovascular endpoints are warranted.

The cotton bollworm Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is an important pest of many crops that has developed resistance to almost all groups of insecticides used for its management. Insecticide resistance was often related to Transposable Element (TE) insertions near specific genes. In the present study, we deeply retrieve and annotate TEs in the H. armigera genome using the Pipeline to Retrieve and Annotate Transposable Elements, PiRATE. The results have shown that the TE library consists of 8521 sequences representing 236,132 TE copies, including 3133 Full-Length Copies (FLC), covering 12.86% of the H. armigera genome. These TEs were classified as 46.71% Class I and 53.29% Class II elements. Among Class I elements, Short and Long Interspersed Nuclear Elements (SINEs and LINEs) are the main families, representing 21.13% and 19.49% of the total TEs, respectively. Long Terminal Repeat (LTR) and Dictyostelium transposable element (DIRS) are less represented, with 5.55% and 0.53%, respectively. Class II elements are mainly Miniature Inverted Transposable Elements (MITEs) (49.11%), then Terminal Inverted Repeats (TIRs) (4.09%). Superfamilies of Class II elements, i.e., Transib, P elements, CACTA, Mutator, PIF-harbinger, Helitron, Maverick, Crypton and Merlin, were less represented, accounting for only 1.96% of total TEs. In addition, we highlighted TE insertions in insecticide resistance genes and we successfully identified nine TE insertions belonging to RTE, R2, CACTA, Mariner and hAT superfamilies. These insertions are hosted in genes encoding cytochrome P450 (CyP450), glutathione S-transferase (GST), and ATP-binding cassette (ABC) transporter belonging to the G and C1 family members. These insertions could therefore be involved in insecticide resistance observed in this pest.

Composition of lipids, sterols, fatty acids (FA), and phospholipids in the edible Rhodophyta Grateloupia turuturu from Britanny, France, was investigated over four seasons in order to identify compounds with potential benefits in health and nutrition. The lipid content was found to vary from 3.3 to 4.1 % dry weight. No marked variations were observed for glycolipids accounting for 42.3–46.8 %, whereas neutral lipids and phospholipids fluctuated from 20.1 % (summer) to 41.8 % (winter), and 11.2 % (winter) to 33.4 % (summer), respectively. Polyunsaturated FA of the total lipids were found from 20.4 % (winter) to 31.1 % (summer), including 20:5 ω3 acid as the major one (up to 16.3 % in summer). Phosphatidylcholine (20.0–43.7 %) and phosphatidylserine (24.6–37.5 %) were the dominant phospholipids in all seasons. Compounds of interest were identified in minor amounts such as squalene, α-tocopherol, phytonadione (vitamin K₁), cholesteryl formate, cholest-4-en-3-one, and cholesta-4,6-dien-3-one. Cholesterol was the major sterol with a lower content in spring and summer.

Aim Nicotinic acid (NA) treatment decreases plasma triglycerides and increases HDL cholesterol, but the mechanisms involved in these change are not fully understood. A reduction in cholesteryl ester transfer protein (CETP) activity has been advanced to explain most lipid-modulating effects of NA. However, due to the central role of CETP in reverse cholesterol transport in humans, other effects of NA may have been hidden. As dogs have no CETP activity, we conducted this study to examine the specific effects of extended-release niacin (NA) on lipids and high-density lipoprotein (HDL) cholesteryl ester (CE) turnover in obese Insulin-Resistant dogs with increase plasma triglycerides. Methods HDL kinetics were assessed in fasting dogs before and four weeks after NA treatment through endogenous labeling of cholesterol and apolipoprotein AI by simultaneous infusion of [1,2 C-13(2)] acetate and [5,5,5 H-2(3)] leucine for 8 h. Kinetic data were analyzed by compartmental modeling. In vitro cell cholesterol efflux of serum from NA-treated dogs was also measured. Results NA reduced plasma total cholesterol, low-density lipoprotein cholesterol, HDL cholesterol, triglycerides (TG), and very-low-density lipoprotein TG concentrations (p < 0.05). The kinetic study also showed a higher cholesterol esterification rate (p < 0.05). HDL-CE turnover was accelerated (p < 0.05) via HDL removal through endocytosis and selective CE uptake (p < 0.05). We measured an elevated in vitro cell cholesterol efflux (p < 0.05) with NA treatment in accordance with a higher cholesterol esterification. Conclusion NA decreased HDL cholesterol but promoted cholesterol efflux and esterification, leading to improved reverse cholesterol transport. These results highlight the CETP-independent effects of NA in changes of plasma lipid profile.

Abstract Foraminifera are ubiquitously distributed in marine habitats, playing a major role in marine sediment carbon sequestration and the nitrogen cycle. They exhibit a wide diversity of feeding and behavioural strategies (heterotrophy, autotrophy and mixotrophy), including species with the ability of sequestering intact functional chloroplasts from their microalgal food source (kleptoplastidy), resulting in a mixotrophic lifestyle. The mechanisms by which kleptoplasts are integrated and kept functional inside foraminiferal cytosol are poorly known. In our study, we investigated relationships between feeding strategies, kleptoplast spatial distribution and photosynthetic functionality in two shallow-water benthic foraminifera ( Haynesina germanica and Elphidium williamsoni ), both species feeding on benthic diatoms. We used a combination of observations of foraminiferal feeding behaviour, test morphology, cytological TEM-based observations and HPLC pigment analysis, with non-destructive, single-cell level imaging of kleptoplast spatial distribution and PSII quantum efficiency. The two species showed different feeding strategies, with H. germanica removing diatom content at the foraminifer’s apertural region and E. williamsoni on the dorsal site. All E. williamsoni parameters showed that this species has higher autotrophic capacity albeit both feeding on benthic diatoms. This might represent two different stages in the evolutionary process of establishing a permanent symbiotic relationship, or may reflect different trophic strategies.