Levels Of Monogalactosyldiacylglycerol Research Articles

UHPLC-MS/MS-BASED PLASMA LIPIDOMICS REVEAL ALTERATIONS ASSOCIATED WITH EXCLUSIVE ENTERAL NUTRITION TREATMENT IN ADULT PATIENTS WITH ACTIVE CROHN’S DISEASE

Abstract BACKGROUND Exclusive enteral nutrition (EEN) is an effective treatment for active Crohn’s disease (CD), although the mechanisms is unclear. Lipid metabolism and signaling have been suggested to play an important role in the pathophysiology of the disease, but their relationship with EEN therapy has not been reported. Hence, we assessed plasma lipid profiles of adult patients with active CD before and after EEN and compared them to those of healthy controls. METHODS Adult patients with active CD (n=11) who received EEN with an amino acid-based enteral nutrition formula for 12 weeks and age- and sex-matched healthy controls (n=17) were recruited. Plasma lipid profiles of 869 lipid species were measured before and after EEN in both groups using ultrahigh performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The CD activity index (CDAI), high-sensitivity C-reactive protein (hs-CRP) level, and nutrition-associated indices were evaluated. CDAI <150 and a Simple Endoscopic Score for CD (SES-CD) ≤2 indicated clinical remission and mucosal healing (MH), respectively. RESULTS After 12 weeks of EEN, 81.8% (9 of 11) patients achieved remission with a significant decrease in the CDAI (P<0.001) and hs-CRP levels (P<0.001). Ten patients had a SES-CD score of >2 before EEN, which declined after EEN (P=0.009), with four patients achieving MH. Before EEN initiation, 80 lipid species/17 lipid classes were significantly different between patients with CD and healthy controls. After EEN initiation, 103 lipid species/11 lipid classes were significantly different between patients with CD and healthy controls. Thirty-eight significantly different lipid species from eight lipid classes—cholesterolester (n=1), lysophosphatidylcholine (n=3), monogalactosyldiacylglycerol (n=1), phosphatidylcholine (n=18), phosphatidylethanolamine (n=3), phosphatidylinositol (n=4), phosphatidylserine (n=1), and phosphatidylglycerol (n=7)—were identified in patients with CD before and after EEN. Among these lipid classes, the levels of monogalactosyldiacylglycerol, phosphatidylinositol, and phosphatidylcholine decrased significantly and that of phosphatidylglycerol increased significantly before EEN in patients with CD compared to those in healthy controls (P<0.05). These lipids returned to similar levels of healthy controls after EEN (P>0.05). Lipid classes and species were significantly associated with clinical indices of CDAI, hs-CRP, and MH. Pathway analysis suggested that arachidonic acid, glycerophospholipid, linoleate, and phosphatidylinositol phosphate metabolisms were related to the mechanism of EEN treatment. CONCLUSION EEN leads to the alterations in multiple lipid classes and species, in keeping with improvement in clinical response. However, further studies are needed to confirm their precise roles.

Altered lipidomic profiles in lung and serum of rat after sub-chronic exposure to ozone

Ozone (O) exposure not only causes lung injury and lung inflammation but also changes blood composition. Previous studies have mainly focused on inflammatory processes and metabolic diseases caused by acute or chronic ozone exposure. However, the effect of ozone on lipid expression profiles remains unclear. This study aimed to investigate the lipidomic changes in lung tissue and serum of rats after ozone exposure for three months and explore the lipid metabolic pathway involved in an ozone-induced injury. Based on the non-targeted lipidomic analysis platform of the UPLC Orbitrap mass spectrometry system, we found that sub-chronic exposure to ozone significantly changed the characteristics of lipid metabolism in lungs and serum of rats. First, the variation in sphingomyelin (SM) and triglyceride (TG) levels in the lung and serum after O3 exposure are shown. SM decreased in both tissues, while TG decreased in the lungs and increased in the serum. Further, the effect of ozone on glycerophospholipids in the lung and serum was completely different. Phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylinositol (PI) were the major glycerophospholipids whose levels were altered in the lung, while phosphatidylglycerol (PG), phosphatidic acid (PA), and phosphatidylcholine (PC) levels changed dramatically in the serum. Third, after O3 exposure, the level of monogalactosyldiacylglycerol (MGDG), mainly MGDG (43, 11), a saccharolipid, declined significantly and uniquely in the serum. These results suggested that sub-chronic O3 exposure may play a role in the development of several diseases through perturbation of lipidomic profiles in the lungs and blood. In addition, changes in the lipids of the lung and blood may induce or exacerbate respiratory diseases.

Overexpression of human peroxisomal enoyl-CoA delta isomerase2 HsPECI2, an ortholog of bamboo expressed during gregarious flowering alters salinity stress responses and polar lipid content in tobacco.

Peroxisomal enoyl-CoA delta isomerase2 (PECI2) is one of the key enzymes that has critical role in lipid metabolism and plant development during salt stress. Seven out of ten tobacco plants overexpressing human PECI2 (HsPECI2) with PTS1-sequence showed hypersensitivity to salt. Under salt-stress, T2 transformed plants (HsPECI2) displayed reduced primary root, delayed shoot-growth, and visibly smaller rosette leaves turning pale yellow as compared to the pKYLX71 vector control plant. Also, we found altered reactive oxygen species (ROS) levels and reduced catalase activity in 100mM sodium chloride (NaCl) treated HsPECI2 transformed plant compared with the pKYLX71 counterpart. ESI-MS/MS data showed that the polar lipids were differentially modulated upon salt treatment in HsPECI2 transformed and pKYLX71 plants as compared with the respective untreated counterpart. Notably, the levels of monogalactosyldiacylglycerol and phosphatidic acid varied significantly, whereas phosphatidylcholine, phosphatidylserine and digalactosyldiacylglycerol contents were moderately upregulated. In parallel, abscisic acid (ABA) responsiveness assay confirmed insensitivity of HsPECI2 transformed plant towards ABA. Overall our data proclaim that HsPECI2 play multifunctional role in normal development and response to salinity stress apart from its primary role in β-oxidation.

Positive effects of salicylic acid pretreatment on the composition of flax plastidial membrane lipids under cadmium stress.

Interest in use of flax (Linum usitatissimum L.) as cadmium (Cd)-accumulating plant for phytoextraction of contaminated soils opened up a new and promising avenue toward improving tolerance of its varieties and cultivars to Cd stress. The aim of this study is to get insights into the mechanisms of Cd detoxification in cell membranes, by exploring the effects of salicylic acid (SA)-induced priming on fatty acids and lipid composition of flax plantlets, grown for 10 days with 50 and 100 μM Cd. At leaf level, levels of monogalactosyldiacylglycerol (MGDG), phosphatidylcholine (PC), phosphatidylglycerol (PG), and neutral lipids (NL) have shifted significantly in flax plantlets exposed to toxic CdCl2 concentrations, as compared to that of the control. At 100 μM Cd, the linoleic acid (C18:2) decreases mainly in digalactosyldiacylglycerol (DGDG) and all phospholipid species, while linolenic acid (C18:3) declines mostly in MGDG and NL. Conversely, at the highest concentration of the metal, SA significantly enhances the levels of MGDG, PG and phosphatidic acid (PA), and polyunsaturated fatty acids mainly C18:2 and C18:3. Furthermore, SA pretreatment seems to reduce the Cd-induced alterations in both plastidial and extraplastidial lipid classes, but preferentially preserves the plastidial lipids by acquiring higher levels of polyunsaturated fatty acids. These results suggest that flax plantlets pretreated with SA exhibits more stability of their membranes under Cd-stress conditions.

Expression of a gene for plastid ω‐3 fatty acid desaturase and changes in lipid and fatty acid compositions in light‐ and dark‐ grown wheat leaves

The leaves of monocotyledonous plants create a developmental sequence of cells and plastids from the base to the apical portion. We investigated fatty‐acid and lipid compositions in successive leaf sections of light‐ and dark‐grown wheat (Triticum aestivum L. cv. Chihoku) seedlings. The most notable change in the fatty acid composition was the increase of linolenic acid (18:3) with maturation of leaf cells, which occurred both in light‐ and dark‐grown leaf tissues. In light‐grown leaves, the increase of 18:3 with maturation was mainly attributed to the increase of monogalactosyldiacylglycerol (MGD) and also to the increase of the 18:3 level of MGD. In dark‐grown leaves, the increase of 18:3 in the leaf apex was caused by the increase of the levels of MGD and digalactosyldiacylglycerol (DGD) and also by the increase of the 18:3 levels of within these two lipids. Since MGD and DGD are mainly found in plastid membranes, these findings indicate that both the synthesis of galactolipids and the formation of 18:3 these lipids take place during plastid development. The plastid ω‐3 fatty acid desaturase is responsible for the formation of 18:3 in plastid membrane lipids. To investigate the regulation of desaturation, we isolated a gene for wheat plastid ω‐3 fatty acid desaturase (TaFAD7). The mRNA level of TaFAD7 in light‐grown leaves was much higher than that in dark‐grown leaves. During the greening of etiolated leaves the level of TaFAD7 mRNA increased significantly, accompanied by an increase of the 18:3 level of total fatty acids. On the other hand, the levels of TaFAD7 mRNA were almost the same in all the leaf sections of both light‐ and dark‐grown leaf tissues. These results suggest that the effect of the expression of the TaFAD7 gene on the increase of the 18:3 level is different between the leaf development under continuous light‐ or dark‐conditions and the light‐induced greening process of etiolated leaves. The increase of 18:3 content of MGD (or MGD and DGD) with maturation is apparently regulated not solely by the level of TaFAD7 mRNA.

The characterisation and cyclic production of a highly unsaturated homoserine lipid in Chlorella minutissima

The marine alga Chlorella minutissima contains DGTS (diacylglyceryl- N, N, N-trimethylhomoserine) as a major component (up to 44% of total lipids). This lipid is absent from other members of the Chlorococcales, except for C. fusca, which contains DGTS as 1.3% of total lipids. Contrary to expectation, the DGTS is accompanied by PC (phosphatidylcholine) as the major phospholipid. DGTS is normally highly saturated in the C-1 position of glycerol, but in C. minutissima, both C-1 and C-2 are acylated with EPA (eicosapentaenoic acid, 20:5) in the major molecular species (over 90% of total). The DGTS level shows a marked rhythmic fluctuation with time which is inversely correlated with the level of MGDG (monogalactosyldiacylglycerol), the other major lipid. Improved NMR data and the first electrospray MS data on this lipid are presented.

Effect of triacontanol on the lipid composition of cotton (Gossypium hirsutum L.) leaves and its interaction with indole-3-acetic acid and benzyladenine

Application of triacontanol (TRIA), a long chain aliphatic alcohol (C-30), to cotton (Gossypium hirsutum L.) leaves resulted in an increase in dry weight and an alteration in lipid composition. A significant increase in monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) was attained 24 h after TRIA treatment. However, no significant change in any of the individual phospholipids was observed. Benzyladenine (BA) treatment increased only phosphatidylcholine (PC) levels without having any effect on either glycolipids or other phospholipids. Indole-3-acetic acid (IAA) initiated no significant change in the lipid composition. Combined treatment with TRIA and BA resulted in an increase of MGDG, DGDG and PC, indicating that the individual effects of these two growth regulators were not altered. The combined treatment of IAA and TRIA did not bring about any change in the levels of MGDG and DGDG indicating that the effect of TRIA was nullified by IAA. MDGD is known to be involved in the packaging of photosystem I proteins. Whether TRIA-induced increase in dry weight which is due to the enhanced photosynthetic rate, is related to increased MGDG levels is not yet discernible.

Modulation of lipid and fatty acid content by carbon dioxide in Chlamydomonas reinhardtii

Levels of polar lipids and the composition of fatty acids in individual classes of lipids were analyzed in vegetative cells of Chlamydomonas reinhardtii, grown either in air or in air supplemented with CO 2. The levels of monogalactosyl diacylglycerol (MGDG) and phosphatidylglycerol (PG) were markedly lower in the cells grown in 1% or 3% CO 2 than in the cells grown in air alone. The levels of unsaturated fatty acids in MGDG, PG, digalactosyl diacylglycerol (DGDG) and diacylglyceryltrimethylhomoserine (DGTS) were significantly lower in the cells grown in 1% or 3% CO 2, while the fatty acids in phosphatidylethanolamine (PE) were more unsaturated in these cells than in the cells grown in air. These results suggest that the metabolism of lipids is extensively modulated by CO 2.