Integration of hepatic lipidomics and transcriptomics reveals the effect of butter-derived ruminant trans fatty acids on lipid metabolism in C57BL/6J mice.

Dysregulation of lipid metabolism results in metabolism-related diseases. Our previous research indicated that 1.3% E and 4% E ruminant trans fatty acids (R-TFA) caused dyslipidemia and promoted atherosclerotic plaques in ApoE-/- mice, presenting detrimental effects. However, the effect of R-TFA on the lipid metabolism of normal mice remains unclear. Therefore, our current research aims to explore the effects of butter-derived R-TFAs on the lipid metabolism of C57BL/6J mice through the integration of lipidomics and transcriptomics. As a result, we found that 1.3% E butter-derived R-TFA promoted dyslipidemia and impaired hepatic function in C57BL/6J mice fed a high-fat diet, which was associated with an increase in DG (18:1/22:5), TG (18:1/18:2/22:4) and FA (24:5) as determined through lipidomics analysis, but had a less significant effect on C57BL/6J mice fed a low-fat diet. Through a combination analysis and verification of gene expression, we found that the arachidonic acid pathway might be involved in the disruption of lipid metabolism by butter-derived R-TFA. In addition, butter-derived R-TFA up-regulated the expression of unigene thromboxane-A synthase 1 (Tbxas1), arachidonate lipoxygenase 3 (Aloxe3), acyl-coenzyme A thioesterase 2 (Acot2), epoxide hydrolase 2 (Ephx2) and carbonyl reductase 3 (Cbr3) in C57BL/6J mice fed a high-fat diet. Herein, our research provides a new perspective for exploring the effects of butter-derived R-TFA on lipid metabolism and speculates on the possible mechanism of lipid metabolism disorder induced by butter-derived R-TFA in C57BL/6J mice fed a high-fat diet.

Comparative analysis of the volatile components in Chinese breast milk from three regions.

In this study, gas chromatography-mass spectrometry (GC-MS) coupled with Partial least squares Discriminant Analysis (PLS-DA) was used to analyze the volatiles in Chinese breast milk from different cities (Wuhan, Qingdao and Hohhot) and different lactation stages (colostrum and mature milk). The results showed that breast milk contained 122 volatile substances in 9 major groups, with the largest number of olefins (36) and the highest content of acids. The different volatile compounds of breast milk in three cities were heptanal, 2-pentylfuran, (E)-2,4-decadienal, (E)-2-heptenal, (E)-2-nonenal and 1-octen-3-one, colostrum and mature milk were (E)-2-heptenal, (E)-2-decenal, lauric acid, n-decanoic acid, (E)-2-nonenal and octanoic acid. This study might provide scientific data for the development and optimization of formulas that were more suitable for the health of Chinese infants. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01235-4.

Lipid rafts may affect the coalescence of milk fat globules through phase transition after thermal treatment.

This study aimed to investigate changes of fat globules and their membranes, and further analyze evolution of lipid profile of lipid rafts in membranes during heat processing of cow milk. Size of fat globules increased from 3.16 µm to 3.70 µm and ζ-potential decreased from -0.53 mV to -0.38 mV after thermal treatment, suggesting that fat globule membrane was destroyed and fat globule occurred coalescence. Glycerophospholipids and cholesterol in fat globule membrane decreased while sphingomyelin increased after thermal treatment. Results of lipidomics show that total of 38 species of 5 lipids molecule showed ability to differentiate the samples. At high temperatures, highly unsaturated glycerophospholipids and sterol lipids were lost from rafts, meanwhile, sphingomyelin and ceramide increased in this region. Significant change of lipid profile in the raft region during thermal treatment suggested a potential relationship between lipid rafts and fat globule coalescence behavior.

Butter-Derived Ruminant Trans Fatty Acids Do Not Alleviate Atherosclerotic Lesions in High-Fat Diet-Fed ApoE-/- Mice.

Atherosclerosis (AS) is the most common cardiovascular disease (CVD). Currently, it is widely believed that R-TFA and I-TFA may cause different biological effects. In the present study, we aim to elucidate the effect of mixed R-TFA derived from butter on the development of AS in high-fat diet-fed ApoE-/- mice and find the possible mechanism. It was shown that butter-derived R-TFA promoted dyslipidemia, reduced thoracic and abdominal aorta diameters, and induced aortic lipid deposition and atherosclerotic lesions in high-fat diet-fed ApoE-/- mice. Meanwhile, butter-derived R-TFA affected the serum lipid profile of high-fat diet-fed ApoE-/- mice and the lipid metabolism of human umbilical vein endothelial cells (HUVECs). Through lipidomic techniques, we found that butter-derived R-TFA had a significant effect on the glycerophospholipid metabolic pathway. In conclusion, our results demonstrated that butter-derived R-TFA does not alleviate but promotes atherosclerotic lesions in high-fat diet-fed ApoE-/- mice and that the glycerophospholipid metabolic pathway plays a major role in this pro-atherosclerotic effect.

Cloning, identification of the two cytokine receptor family B subunits CRFB1 and CRFB5 from grass carp (Ctenopharyngodon idella).

Similar to the mammalian counterparts, fish type I interferon (IFN) performs its potential biological activities via binding to the corresponding receptor on target cell membrane. Fish type I IFN receptor, a kind of enzyme-linked receptor, consists of two subunits and belongs to the class II cytokine receptor family B (CRFB). In the present study, we cloned and identified two putative grass carp (Ctenopharyngodon idella) type I interferon receptor subunits (termed CiCRFB1 and CiCRFB5) by homology cloning techniques. Phylogenetic tree analysis suggested that CiCRFB1 and CiCRFB5 shared highly homology to Danio rerio CRFB1 and CRFB5 respectively. CiCRFB1 and CiCRFB5 were up-regulated after the stimulation with Grass Carp Hemorrhagic Virus (GCHV) and Polyinosinic-polycytidylic acid (Poly I:C), indicating that they are related to the intracellular antiviral activity. In order to know more about the roles of CiCRFB1 and CiCRFB5 in the process, the extracellular domains of CiCRFB1 (CiCRFB1-EC) and CiCRFB5 (CiCRFB5-EC), as well as grass carp type I IFN (CiIFN) were expressed in Escherichia coli BL21, and purified by affinity chromatography with the Ni-NTA His-Bind resin. Cross-linking reactions were employed to analyze the affinity of the ligand (CiIFN) with the two putative receptor subunits (CiCRFB1-EC and CiCRFB5-EC). The result suggested the formation of (CiCRFB5)2 homodimer was more easily than that of (CiCRFB1)2 under the induction of CiIFN in vitro. However, CiIFN was inclined to bind to (CiCRFB1)2 homodimer. Interestingly, although CiIFN seemed unable to facilitate the formation of (CiCRFB1 + CiCRFB5) heterodimer in the absence of DSS cross linker, however it can bind to the heterodimer in the presence of DSS. This indicated that the homodimer and the heterodimer were the potential receptor for CiIFN.

Promoter analysis and transcriptional regulation of a Gig2 gene in grass carp (Ctenopharyngodon idella).

Grass carp reovirus (GCRV)-induced gene 2 (Gig2) is recognized as a new antiviral factor involved in response to viral infection. However, little is known about the mechanisms behind the transcriptional regulation of Gig2 when infected by virus. In this study, the upstream promoter region of grass carp (Ctenopharyngodon idella) Gig2 gene (CiGig2) was identified by homology cloning strategy. CiGig2 promoter sequence was found to be 859 bp in length and contained three scattered IFN-stimulated response elements (ISRE). In addition, some grass carp IRFs (CiIRF1, CiIRF2 and CiIRF3) ORF sequences were subcloned into the expression plasmids pET-32a and expressed in Escherichia coli BL21, then the expressed proteins were purified by affinity chromatography with the Ni-NTA His-Bind Resin. Gel mobility shift assay was employed to screen the transcriptional regulatory factor for CiGig2. The results revealed that the recombinant polypeptides of CiIRF1, CiIRF2 and CiIRF3 bound to CiGig2 promoter with high affinity; indicating that IRF1, IRF2 and IRF3 could be the potential transcriptional regulatory factors for Gig2. Subsequently, CiGig2 promoter sequence was cloned into pGL3-Basic vector and the ORFs of CiIRF1, CiIRF2 and CiIRF3 were cloned into the expression plasmids pcDNA3.1 (+). Then, pGL3-CiGig2 promoter sequence and pcDNA3.1-CiIRFs were co-transfected into C. idella kidney (CIK) cells. The in vivo effects of CiIRFs on CiGig2 promoter were measured by dual-luciferase assays in the transfected CIK cells. Our results showed that the roles of CiIRFs were diversified in regulating CiGig2 transcription, e.g., CiIRF3 played a positive role in during this process; on the contrary CiIRF1 worked as a suppressor; however the effect of CiIRF2 on CiGig2 transcription was not obvious. For further study the roles of the three ISREs in CiGig2 transcription, we cloned three mutant CiGig2 promoters called ISRE1mut-luc (deleted ISRE1), ISRE2mut-luc (deleted ISRE2) and ISRE3mut-luc (deleted ISRE3), respectively. In vitro, gel mobility shift assays showed that all three mutant promoters also were combined with CiIRFs. CIK cells were co-transfected with CiGig2 promoter mutants (ISRE1mut-luc, ISRE2mut-luc or ISRE3mut-luc, respectively) and pcDNA3.1-IRFs. The results suggested that different ISRE played the diverse roles. ISRE2 is more important than ISRE1 and ISRE3 to the transcription of CiGig2 induced by CiIRF1. ISRE1 and ISRE3 are important to the transcription of CiGig2 induced by CiIRF2 and CiIRF3.

Metabolomic analysis of amino acid metabolism in colitic rats supplemented with lactosucrose.

Intestinal inflammation causes metabolic disorders. The purpose of this study was to determine the effect of dietary supplementation with lactosucrose (LS) on the serum metabolome and intestinal luminal content of fatty acids in colitic rats. Colitis was induced in rats using trinitrobenzene sulfonic acid. Subsequently, rats received intragastric administration of either 250 mg LS/kg body weight or saline (the control group) every day for 5 weeks. Short-chain fatty acids in the intestinal lumen, blood profile, and metabolites in serum were measured, respectively, using gas chromatography, biochemistry analyzer, and nuclear magnetic resonance-based metabolomics combined with multivariate statistics. Metabolic effects of LS included: (1) decreases in concentrations of branched-chain amino acids (isoleucine and valine), alanine, citric acid, trimethylamine oxide and taurine, and the abundance of aspartate aminotransferase in serum; (2) increases in concentrations of glucose metabolites (including succinate) in serum; and (3) altered concentrations of butyrate in the cecal content and of butyrate and acetate in the colon content. The results indicate that LS supplementation to colitic rats affects whole-body metabolism of amino acids and release of aspartate aminotransferase and alkaline phosphatase from tissues into the blood circulation, and enhances the production of short-chain fatty acids in the intestinal lumen.