Solid monounsaturated diet lowers LDL unsaturation trait and oxidisability in hypercholesterolemic (type IIb) patients

Lowering high cholesterol concentration decreases the probability of atherosclerotic-related pathology onset. MUFA and PUFA decrease total plasma and LDL cholesterol but PUFA may increase the susceptibility of LDL to undergo oxidative modifications thus becoming more atherogenetic. Olive oil, the predominant fat source in Mediterranean diet, may combine the advantages of both lowering cholesterol level and decreasing LDL susceptibility to oxidation. We studied the effects of feeding MUFA vs PUFA enriched diet on LDL composition and feature in hypercholesterolemic (IIb) patients. Antioxidant values remained constant during the study while LDL fatty acids composition reflected the dietary intake: MUFA concentration increased 11% whereas PUFA decreased 10% after olive oil diet (p < 0.05). PUFA/MUFA ratio and the unsaturation index were lower at the end of MUFA-enriched diet. The challenge, in vitro, of oleate-enriched LDL with Cu2- yielded to lower lag-phase (p < 0.05) in diene conjugated production; the same LDL gave lower lipid hydroperoxide contents after exposition to AAPH. We conclude that oleate-enriched LDL and with lower PUFA content were more resistant to oxidative modifications, as measured by different peroxidation indexes. This feature acquired with the diet may be an useful tool for lowering LDL oxidation and indirectly their atherogenicity.     

Atherogenic phospholipids attenuate osteogenic signaling by BMP-2 and parathyroid hormone in osteoblasts

Cardiovascular disease, such as atherosclerosis, has been associated with reduced bone mineral density and fracture risk. A major etiologic factor in atherogenesis is believed to be oxidized phospholipids. We previously found that these phospholipids inhibit spontaneous osteogenic differentiation of marrow stromal cells, suggesting that they may account for the clinical link between atherosclerosis and osteoporosis. Currently, anabolic agents that promote bone formation are increasingly used as a new treatment for osteoporosis. It is not known, however, whether atherogenic phospholipids alter the effects of bone anabolic agents, such as bone morphogenetic protein (BMP)-2 and parathyroid hormone (PTH). Therefore we investigated the effects of oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (ox-PAPC) on osteogenic signaling induced by BMP-2 and PTH in MC3T3-E1 cells. Results showed that ox-PAPC attenuated BMP-2 induction of osteogenic markers alkaline phosphatase and osteocalcin. Ox-PAPC also inhibited both spontaneous and BMP-induced expression of PTH receptor. Consistently, pretreatment of cells with ox-PAPC inhibited PTH-induced cAMP production and expression of immediate early genes Nurr1 and IL-6. Results from immunofluorescence and Western blot analyses showed that inhibitory effects of ox-PAPC on BMP-2 signaling were associated with inhibition of SMAD 1/5/8 but not p38-MAPK activation. These effects appear to be due to ox-PAPC activation of the ERK pathway, as the ERK inhibitor PD98059 reversed ox-PAPC inhibitory effects on BMP-2-induced alkaline phosphatase activity, osteocalcin expression, and SMAD activation. These results suggest that atherogenic lipids inhibit osteogenic signaling induced by BMP-2 and PTH, raising the possibility that hyperlipidemia and atherogenic phospholipids may interfere with anabolic therapy.     

Genetic and Epigenetic Dynamics of a Retrotransposon After Allopolyploidization of Wheat

Allopolyploidy, or the combination of two or more distinct genomes in one nucleus, is usually accompanied by radical genomic changes involving transposable elements (TEs). The dynamics of TEs after an allopolyploidization event are poorly understood. In this study, we analyzed the methylation state and genetic rearrangements of a high copied, newly amplified terminal-repeat retrotransposon in miniature (TRIM) family in wheat termed Veju. We found that Veju insertion sites underwent massive methylation changes in the first four generations of a newly formed wheat allohexaploid. Hypomethylation or hypermethylation occurred in ∼43% of the tested insertion sites; while hypomethylation was significantly predominant in the first three generations of the newly formed allohexaploid, hypermethylation became predominant in the subsequent generation. In addition, we determined that the methylation state of Veju long terminal repeats (LTRs) might be correlated with the deletion and/or insertion of the TE. While most of the methylation changes and deletions of Veju occurred in the first generation of the newly formed allohexaploid, most Veju insertions were seen in the second generation. Finally, using quantitative PCR, we quantitatively assessed the genome composition of Veju in the newly formed allohexaploid and found that up to 50% of Veju LTRs were deleted in the first generation. Retrotransposition bursts in subsequent generations, however, led to increases in Veju elements. In light of these findings, the underlying mechanisms of TRIM rearrangements are discussed.TRANSPOSABLE elements (TEs) are DNA sequences that range in size from several hundred base pairs to >15 kb and that have the ability to move to different locations within the genome. TE movement occurs through either a copy-and-paste mechanism involving RNA intermediates (class 1) or a cut-and-paste mechanism involving DNA intermediates (class 2). Class 1 elements are also called retrotransposons, or retroelements, and comprise two main types: (1) long terminal repeat (LTR) retrotransposons, flanked by LTRs, and (2) non-LTR elements (such as long interspersed nuclear elements and short interspersed nuclear elements).LTR retrotransposons are the most abundant mobile elements in plant genomes (Feschotte et al. 2002), as the replicative mode of retroelement transposition enables the LTR retrotransposon to accrue in high copy number. Indeed, in some grasses, LTR retrotransposons represent up to 90% of the genome (Bennetzen and Kellogg 1997; Feschotte et al. 2002). As such, retrotransposon sequences function well as substrates for illegitimate and unequal recombinations that can lead to a variety of mutations, such as deletions, insertions, translocations, and others (Parisod et al. 2009).The replicative nature of TEs seems to be stimulated by a variety of specific stress conditions (reviewed by Wessler 1996; Capy et al. 2000; Grandbastien et al. 2005), including challenges to the genome such as interspecific hybridization, an idea first proposed by Barbara McClintock 26 years ago (McClintock 1984). Accordingly, allopolyploidization is usually coupled with rapid and reproducible genomic changes, including the elimination of DNA sequences (Liu et al. 1998a,b; Ozkan et al. 2001; Shaked et al. 2001; Adams and Wendel 2005b; Skalicka et al. 2005), gene silencing (Chen and Pikaard 1997; Comai et al. 2000; Kashkush et al. 2002; Simons et al. 2006), alteration of cytosine methylation (Shaked et al. 2001; Madlung et al. 2002; Salmon et al. 2005; Beaulieu et al. 2009; Xu et al. 2009), activation of genes and retrotransposons (Kashkush et al. 2002, 2003; O''Neill et al. 2002), massively altered gene expression patterns (Kashkush et al. 2002; Wang et al. 2006), and organ-specific subfunctionalization, i.e., differential expression of homeoalleles in different tissues and at different developmental stages (Adams et al. 2003; Adams and Wendel 2004). These and other studies (Levy and Feldman 2002; Osborn et al. 2003; Adams and Wendel 2005a; Rapp and Wendel 2005; Chen and Ni 2006; Chen 2007) demonstrate the dynamic nature of allopolyploid plant genomes.Although allopolyploidization has generally been assumed to induce large bursts of TE activity (Matzke and Matzke 1998), several studies that focused on different allopolyploid systems failed to provide any evidence for a transposition burst and offered only limited evidence for the transposition of specific TEs (Madlung et al. 2005; Ainouche et al. 2009; Beaulieu et al. 2009). In newly formed Arabidopsis allopolyploids, no evidence for transposition bursts was reported (Beaulieu et al. 2009), although limited evidence suggested that transposition events occurred in a specific TE called Sunfish (Madlung et al. 2005). Little evidence of TE transposition was found in a natural population of the 150-year-old allopolyploid, Spartina anglica (Ainouche et al. 2009), and no evidence of transposition of Wis 2-1A retrotransposons in a newly formed wheat allotetraploid was present (Kashkush et al. 2003). The results of these works and others indicate that, in the short term, TE proliferation after allopolyploidization may be restricted to a few specific TEs in particular allopolyploidy systems (Parisod et al. 2009).This study entailed a detailed investigation of the methylation patterns and rearrangements of a one terminal-repeat retrotransposon in miniature (TRIM) family in wheat termed Veju. TRIM elements possess the classical structure of LTR retrotransposons, but they are distinguished by their small overall sizes (0.4 to ∼2.5 kb). A nonautonomous retrotransposon, Veju is 2520 bp long with 374 bp of identical LTRs, yet does not contain the proteins required for retrotransposition (Sanmiguel et al. 2002). However, because Veju elements contain polypurine tracts (PPTs) and primer binding sites (PBSs), they are capable of transposing if the retrotransposition proteins are available from another source. In addition, the identical sequences of the Veju 5′ and 3′ LTRs indicate that some members of the Veju family retain retrotransposition activity.In silico analysis of Veju sequences revealed them to be one of the most active and most recently inserted sequences in the wheat genome (Sanmiguel et al. 2002; Sabot et al. 2005a). As such, we have determined and compared the methylation patterns of >880 Veju insertion sites in the first four generations of a newly formed wheat allohexaploid, as well as in the parental lines. We then tested the correlation between the cytosine methylation and genetic rearrangements (i.e., deletions and insertions) of Veju and addressed the precise developmental timing of these rearrangements. Finally, we successfully tested overall changes in the copy numbers of Veju in the newly formed allohexaploid using real-time quantitative PCR.     

Molecular Evidence of Polyandry in the Citrus Mealybug,Planococcus citri (Hemiptera: Pseudococcidae)

The occurrence of polyandry in Planococcus citri , presumed by earlier observations of mating behavior, was confirmed using microsatellite genotyping of pools of over 400 eggs resulting from controlled crosses of one female with two males. The genetic contribution of both mated males was confirmed in 13 out of 43 crosses. In three crosses it was possible to determine that only the first male fertilized the eggs, which may be due to sperm competition or unviable sperm supply. The microsatellite analysis also allowed the confirmation of aspects of the chromosomal inheritance detected previously in cytogenetic studies in Planococcus citri , namely that only one of the alleles is transmitted by the male, indicating that the males are functionally haploid, supporting the observation of Paternal Genome Elimination (PGE) in these insects.     

The Intermediate Filament Vimentin Mediates MicroRNA miR-378 Function in Cellular Self-renewal by Regulating the Expression of the Sox2 Transcription Factor

MicroRNAs are short noncoding RNAs that are implicated in cell self- renewal and cancer development. We show that miR-378 is up-regulated in human cancers and found that tumor cells transfected with miR-378 acquired properties of tumor stem cells, including cell self-renewal. Overexpression of miR-378 enhanced cell survival and colony formation. Isolated from a single-cell colony, the miR-378-expressing cells formed tumors in nude mice at low cell densities. These cells expressed higher levels of miR-378 and formed more and larger spheres and colonies. We found that the miR-378-expressing cells contained a large number of side population cells and could undergo differentiation. Cells transfected with miR-378 expressed increased levels of Sox2. Expression of miR-378 and Sox2 was found correlated significantly in cancer cell lines and in cancer patient specimens. We also observed opposite levels of vimentin in the cancer cell lines and human breast carcinoma specimens. We further demonstrated that vimentin is a target of miR-378, and ectopic transfection of vimentin inhibited Sox2 expression, resulting in decreased cell survival. Silencing vimentin promoted Sox2 expression and cell survival. Our study demonstrates that miR-378 is a regulator of stem cell marker Sox2 by targeting vimentin, which may serve as a new tool in studying the role of stem cells in tumorigenesis.     

The phylogeny of Dendropsophini (Anura: Hylidae: Hylinae)

The relationships of the hyline tribe Dendropsophini remain poorly studied, with most published analyses dealing with few of the species groups of Dendropsophus. In order to test the monophyly of Dendropsophini, its genera, and the species groups currently recognized in Dendropsophus, we performed a total evidence phylogenetic analysis. The molecular dataset included sequences of three mitochondrial and five nuclear genes from 210 terminals, including 12 outgroup species, the two species of Xenohyla, and 93 of the 108 recognized species of Dendropsophus. The phenomic dataset includes 46 terminals, one per species (34 Dendropsophus, one Xenohyla, and 11 outgroup species). Our results corroborate the monophyly of Dendropsophini and the reciprocal monophyly of Dendropsophus and Xenohyla. Some species groups of Dendropsophus are paraphyletic (the D. microcephalus, D. minimus, and D. parviceps groups, and the D. rubicundulus clade). On the basis of our results, we recognize nine species groups; for three of them (D. leucophyllatus, D. microcephalus, and D. parviceps groups) we recognize some nominal clades to highlight specific morphology or relationships and facilitate species taxonomy. We further discuss the evolution of oviposition site selection, where our results show multiple instances of independent evolution of terrestrial egg clutches during the evolutionary history of Dendropsophus.     

Oncostatin M inhibits differentiation of rat stem Leydig cells in vivo and in vitro

Oncostatin M (OSM) is a pleiotropic cytokine within the interleukin six family of cytokines, which regulate cell growth and differentiation in a wide variety of biological systems. However, its action and underlying mechanisms on stem Leydig cell development are unclear. The objective of the present study was to investigate whether OSM affects the proliferation and differentiation of rat stem Leydig cells. We used a Leydig cell regeneration model in rat testis and a unique seminiferous tubule culture system after ethane dimethane sulfonate (EDS) treatment to assess the ability of OSM in the regulation of proliferation and differentiation of rat stem Leydig cells. Intratesticular injection of OSM (10 and 100 ng/testis) from post‐EDS day 14 to 28 blocked the regeneration of Leydig cells by reducing serum testosterone levels without affecting serum luteinizing hormone and follicle‐stimulating hormone levels. It also decreased the levels of Leydig cell‐specific mRNAs (Lhcgr, Star, Cyp11a1, Hsd3b1, Cyp17a1 and Hsd11b1) and their proteins by the RNA‐Seq and Western blotting analysis. OSM had no effect on the proliferative capacity of Leydig cells in vivo. In the seminiferous tubule culture system, OSM (0.1, 1, 10 and 100 ng/mL) inhibited the differentiation of stem Leydig cells by reducing medium testosterone levels and downregulating the expression of Leydig cell‐specific genes (Lhcgr, Star, Cyp11a1, Hsd3b1, Cyp17a1 and Hsd11b1) and their proteins. OSM‐mediated action was reversed by S3I‐201 (a STAT3 antagonist) or filgotinib (a JAK1 inhibitor). These data suggest that OSM is an inhibitory factor of rat stem Leydig cell development.