Differential mRNA expression of seven genes involved in cholesterol metabolism and transport in the liver of atherosclerosis-susceptible and -resistant Japanese quail strains

An insight into vitamin E and lipid nutrition of the plains-wanderer Pedionomus torquatus

Vitamin E, as α-tocopherol, is an essential antioxidant protecting the body from free radicals. The vitamin E requirement of managed wildlife species is known to be greater than their wild counterparts, predominantly due to higher dietary lipid content and potentially stressful environments. The plains-wanderer (Pedionomus torquatus, Family Pedionomidae [monotypical]) is a critically endangered, superficially quail-like bird that is the focus of an ongoing captive breeding programme in Australia. It is estimated that plains-wanderers have a high vitamin E requirement (compared with domestic poultry species) to offset a high lipid diet and their naturally flighty temperament. This study therefore aims to gain a greater understanding of the nutritional status and vitamin E requirements of plains-wanderers in managed environments. Total lipid and α-tocopherol intake were quantified for 26 zoo-managed plains-wanderers over a series of diet intake trials in addition to measurement of plasma α-tocopherol and cholesterol concentrations. Plains-wanderers that consumed higher portions of dietary fat had significantly lower circulating α-tocopherol concentrations than birds that consumed lower total dietary fat (p < .001). Additionally, plasma cholesterol concentrations of managed plains-wanderers were found to be significantly greater than all other bird species reviewed, irrespective of Family or feeding type. We also present the first published data quantifying the nutritional makeup of stomach contents of a wild plains-wanderer for use as a potential guide for diet formulation. This study forms a vital foundational insight into the nutritional management of plains-wanderers, but further research is required to understand their dietary habits and cholesterol metabolism.

Integrated transcriptomic and proteomic analyses reveal the mechanism of easy acceptance of artificial pelleted diets during food habit domestication in Largemouth bass (Micropterus salmoides)

Acceptance of artificial pelleted diets contributes to increasing the cultured areas and output of carnivorous fish. However, the mechanism of acceptance of artificial pelleted diets remains largely unknown. In this study, the easy acceptance of artificial pelleted diets (EAD) group and the not easy acceptance of artificial pelleted diets (NAD) group of Largemouth bass (Micropterus salmoides) were divided based on the ratios of stomach weight/body weight (SB) after 0.5 h feeding, which was bigger than 18% in the EAD group and ranged from 8 to 12% in the NAD group. Through transcriptome and proteome sequencing, a total of 2463 differentially expressed genes (DEGs) and 230 differentially expressed proteins (DEPs) were identified, respectively. Integrated analyses of transcriptome and proteome data revealed that 152 DEPs were matched with the corresponding DEGs (named co-DEGs-DEPs), and 54 co-DEGs-DEPs were enriched in 16 KEGG pathways, including the metabolic pathways, steroid biosynthesis, fatty acid biosynthesis, etc. Furthermore, 3 terpenoid backbone biosynthesis-related genes (Hmgcr, Hmgcs, and Fdps) in metabolic pathways, 10 steroid biosynthesis-related genes (Fdft1, Sqle, Lss, Cyp51a1, Tm7sf2, Nsdhl, Hsd17b7, Dhcr24, Sc5d, and Dhcr7), and 3 fatty acid biosynthesis-related genes (Acaca, Fasn, and Ascl) were all up-regulated in the EAD group, suggesting that the lipid metabolism pathway and steroid biosynthesis pathway play important roles in early food habit domestication in Largemouth bass. In addition, the detection results of randomly selected 15 DEGs and 15 DEPs indicated that both transcriptome and proteome results in the study were reliable. Our study provides useful information for further research on the mechanisms of food habit domestication in fish.

RNA Sequencing-Based Whole-Transcriptome Analysis of Friesian Cattle Fed with Grape Pomace-Supplemented Diet

Simple Summary

Grape pomace (GPO) is an important source of polyphenols which are known to have antioxidant properties. In the past decade, GPO has received some attention as a bioactive dietary component in farm animals’ diet. In this study, we have analyzed the whole-transcriptome of Friesian calves fed with a GPO-supplemented diet using RNA-sequencing. We noted that the most affected pathway was the cholesterol lipid biosynthesis and this effect was consistent with a reduction in both serum cholesterol and lipid oxidation in the carcasses. This study provides evidence on the antioxidant property of GPO-supplemented diet, from a molecular biology standpoint.

Abstract

Grape pomace (GPO), the main by-product of the wine making process, is a rich source of polyphenols with potent antioxidant properties. Recently, GPO has emerged as a potential feed additive in livestock nutrition, with several reports describing its beneficial effects on animals’ overall health status or production traits. However, little is known about it from a molecular biology standpoint. In the present study, we report the first RNA sequencing-based whole-transcriptome profiling of Friesian calves fed with a GPO-supplemented diet. We identified 367 differentially expressed genes (p < 0.05) in the GPO-supplemented calves (n = 5), when compared with unsupplemented control group (n = 5). The pathway analysis showed that ‘cholesterol lipid biosynthesis’ was the most negatively-enriched (p < 0.001) pathway in the GPO-supplemented animals. In specific terms, five important genes coding for cholesterol biosynthesis enzymes, namely the Farnesyl-diphosphate Farnesyltransferase 1 (FDFT-1), Squalene Epoxidase (SQLE), NAD(P)-dependent Steroid Dehydrogenase-like (NSDHL), Methylsterol Monooxygenase (MSMO)-1, and Sterol-C5-desaturase (SC5D), two major transcription factors (the Sterol Regulatory Element-binding Transcription Factor 1 and 2), as well as the Low-Density Lipoprotein Receptor (LDLR), were all downregulated following GPO supplementation. Such an effect was mirrored by a reduction of blood cholesterol levels (p = 0.07) and a lowered (p < 0.001) Malondialdehyde (lipid oxidation marker) level in carcasses. We provide evidence on the effects of GPO-supplemented diets on the whole-transcriptome signature in veal calves, which mainly reflects an antioxidant activity.

Interaction of genotype and diet on small intestine microbiota of Japanese quail fed a cholesterol enriched diet

Our previous study has shown that genetic selection for susceptibility/resistance to diet-induced atherosclerosis has affected the Japanese quail's cecal environment to accommodate distinctly different cecal microbiota. In this study, we fed the Atherosclerosis-resistant (RES) and -susceptable (SUS) quail a regular and a cholesterol enriched diet to examine the interaction of host genotype and diet on the diversity, composition, and metabolic functions of the duodenal and ileal microbiota with relations to atherosclerosis development. In the duodenal content, 9 OTUs (operational taxonomic units) were identified whose abundance had significant positive correlations with plasma total cholesterol, LDL level and/or LDL/HDL ratio. In the ileal content, 7 OTUs have significant correlation with plasma HDL. Cholesterol fed RES hosted significantly less Escherichia and unclassified Enterobacteriaceae (possibly pathogenic) in their duodenum than SUS fed the same diet. Dietary cholesterol significantly decreased the duodenal microbiome of SUS's biosynthesis of Ubiquinone and other terpenoid-quinone. Cholesterol fed RES had significantly more microbiome genes for Vitamin B6, selenocompound, taurine and hypotaurine, and Linoleic acid metabolism; Bisphenol degradation; primary bile acid, and butirosin and neomycin biosynthesis than SUS on the same diet. Microbiome in the ileum and ceca of RES contributed significantly towards the resistance to diet induced atherosclerosis.

Prediction and analysis of essential genes using the enrichments of gene ontology and KEGG pathways

Identifying essential genes in a given organism is important for research on their fundamental roles in organism survival. Furthermore, if possible, uncovering the links between core functions or pathways with these essential genes will further help us obtain deep insight into the key roles of these genes. In this study, we investigated the essential and non-essential genes reported in a previous study and extracted gene ontology (GO) terms and biological pathways that are important for the determination of essential genes. Through the enrichment theory of GO and KEGG pathways, we encoded each essential/non-essential gene into a vector in which each component represented the relationship between the gene and one GO term or KEGG pathway. To analyze these relationships, the maximum relevance minimum redundancy (mRMR) was adopted. Then, the incremental feature selection (IFS) and support vector machine (SVM) were employed to extract important GO terms and KEGG pathways. A prediction model was built simultaneously using the extracted GO terms and KEGG pathways, which yielded nearly perfect performance, with a Matthews correlation coefficient of 0.951, for distinguishing essential and non-essential genes. To fully investigate the key factors influencing the fundamental roles of essential genes, the 21 most important GO terms and three KEGG pathways were analyzed in detail. In addition, several genes was provided in this study, which were predicted to be essential genes by our prediction model. We suggest that this study provides more functional and pathway information on the essential genes and provides a new way to investigate related problems.

SIRT1/Atg5/autophagy are involved in the antiatherosclerosis effects of ursolic acid

The purpose of this study was to investigate the antiatherosclerosis effects of ursolic acid (UA) in high-fat diet-fed quails (Coturnix coturnix) and potential mechanism. Quails were treated with high-fat diet (14 % pork oil, 1 % cholesterol w/w) with or without UA (50, 150, or 300 mg/kg/day) for 10 weeks. Serum lipid profile was assessed at 0, 4.5, and 10 weeks. After 10 weeks, serum antioxidant status and morphology of aorta were assessed. Additionally, human umbilical vein endothelial cells (HUVECs) were exposed to 100 μg/ml oxidized low-density lipoprotein (ox-LDL) for 24 h, with or without pretreatment with UA (5, 10 or 20 μM) for 16 h, autophagy inhibitor 3-MA 5 mM for 2 h, or SIRT1 inhibitor EX-527 10 μM for 2 h. Cell viability and oxidative stress status were assessed and autophagy status was determined. Acetylation of lysine residue on Atg5 was assessed with immunoprecipitation. In results, high-fat diet negatively affected serum lipid profile and antioxidant status in quails and induced significant histological changes. Cotreatment with UA remarkably alleviated such changes. In HUVECs, ox-LDL treatment induced significant cytotoxicity along with oxidative stress, while UA cotreatment alleviated such changes significantly. UA treatment induced autophagy, enhanced SIRT1 expression, and decreased acetylation of lysine residue on Atg5. Cotreatment with 3-MA or EX-527 effectively abolished UA's protective effects. In summary, UA exerted antiatherosclerosis effects in quails and protected HUVECs from ox-LDL induced cytotoxicity, and the mechanism is associated with increased SIRT1 expression, decreased Atg5 acetylation on lysine residue, and increased autophagy.

How Research on Human Progeroid and Antigeroid Syndromes Can Contribute to the Longevity Dividend Initiative

Although translational applications derived from research on basic mechanisms of aging are likely to enhance health spans and life spans for most of us (the longevity dividend), there will remain subsets of individuals with special vulnerabilities. Medical genetics is a discipline that describes such "private" patterns of aging and can reveal underlying mechanisms, many of which support genomic instability as a major mechanism of aging. We review examples of three classes of informative disorders: "segmental progeroid syndromes" (those that appear to accelerate multiple features of aging), "unimodal progeroid syndromes" (those that impact on a single disorder of aging), and "unimodal antigeroid syndromes," variants that provide enhanced protection against specific disorders of aging; we urge our colleagues to expand our meager research efforts on the latter, including ancillary somatic cell genetic approaches.

The effect of diet and host genotype on ceca microbiota of Japanese quail fed a cholesterol enriched diet

Two Japanese quail strains, respectively atherosclerosis-susceptible (SUS) and –resistant (RES), have been shown to be good models to study cholesterol metabolism and transportation associated with atherosclerosis. Our objective was to examine possible difference in cecal microbiota between these strains when fed a control diet and a cholesterol enriched diet, to determine how host genotype and diet could affect the cecal microbiome that may play a part in cholesterol metabolism. A factorial study with both strains and two diets (control, cholesterol) was carried out. Cecal content was collected from 12 week old quail that have been on their respective diets for 6 weeks. DNA was extracted from the samples and the variable region 3–5 of the bacterial 16S rRNA gene was amplified. The amplicon libraries were subjected to pyrosequencing. Principal Component Analysis (PCA) of β-diversity showed four distinct microbiota communities that can be assigned to the 4 treatment groups (RES/control, RES/cholesterol, SUS/control, SUS/cholesterol). At the Phylum level, the 4 treatment groups has distinct Firmicutes community characteristics but no significant difference in Bacteroidetes. Eubacterium dolichum was rare in RES/control but became overabundant in RES/cholesterol. An unclassified species of Lactobacillaceae was found in abundance in SUS/control but the same species was rare in RES/cholesterol. On the other hand, two Lactobacillus species were only found in RES/control and an unclassified Lachnospiraceae species was abundant in RES/cholesterol but rare in SUS/control. The abundance of four species of Lachnospiraceae, three species of Ruminococcaceae and one species of Coprobacillaceae was positively correlated with plasma Total Cholesterol, plasma LDL, and LDL/HDL ratio. Our study of cecal microbiota in these quail has demonstrated that selection for susceptibility/resistance to diet induced atherosclerosis has also affected the quail's cecal environment to host distinctly different cecal microbiome.

Integromic analysis of genetic variation and gene expression identifies networks for cardiovascular disease phenotypes

BACKGROUND

Cardiovascular disease (CVD) reflects a highly coordinated complex of traits. Although genome-wide association studies have reported numerous single nucleotide polymorphisms (SNPs) to be associated with CVD, the role of most of these variants in disease processes remains unknown.

METHODS AND RESULTS

We built a CVD network using 1512 SNPs associated with 21 CVD traits in genome-wide association studies (at P≤5×10(-8)) and cross-linked different traits by virtue of their shared SNP associations. We then explored whole blood gene expression in relation to these SNPs in 5257 participants in the Framingham Heart Study. At a false discovery rate <0.05, we identified 370 cis-expression quantitative trait loci (eQTLs; SNPs associated with altered expression of nearby genes) and 44 trans-eQTLs (SNPs associated with altered expression of remote genes). The eQTL network revealed 13 CVD-related modules. Searching for association of eQTL genes with CVD risk factors (lipids, blood pressure, fasting blood glucose, and body mass index) in the same individuals, we found examples in which the expression of eQTL genes was significantly associated with these CVD phenotypes. In addition, mediation tests suggested that a subset of SNPs previously associated with CVD phenotypes in genome-wide association studies may exert their function by altering expression of eQTL genes (eg, LDLR and PCSK7), which in turn may promote interindividual variation in phenotypes.

CONCLUSIONS

Using a network approach to analyze CVD traits, we identified complex networks of SNP-phenotype and SNP-transcript connections. Integrating the CVD network with phenotypic data, we identified biological pathways that may provide insights into potential drug targets for treatment or prevention of CVD.

Reciprocal regulation of cholesterol excretion in apolipoprotein E-null mice by angiotensin II type 1 and type 2 receptor deficiency

AIMS

The effects of AT(1) and AT(2) receptor deficiency on the intake and excretion of cholesterol were examined using atherosclerotic apolipoprotein E-null (ApoEKO) mice.

MAIN METHODS

ApoEKO, AT(1)a/ApoEKO and AT(2)/ApoEKO mice received a high-cholesterol diet (HCD: 1.25% cholesterol) for 10 days before sampling.

KEY FINDINGS

Plasma total cholesterol level was lower in AT(1)a/ApoEKO mice and higher in AT(2)/ApoEKO mice than in ApoEKO mice with a high cholesterol intake. In these mice, cholesterol content in feces was higher in AT(1)a/ApoEKO mice and lower in AT(2)/ApoEKO mice than in ApoEKO mice. Moreover, cholesterol content in bile tended to be higher in AT(1)a/ApoEKO mice and lower in AT(2)/ApoEKO mice than in ApoEKO mice, while a significant difference was observed only between AT(1)a/ApoEKO and AT(2)/ApoEKO mice. Cholesterol content and expression of HMG-CoA reductase and LDL receptor in liver were not different among the groups. Similar but weaker changes were also observed with a normal standard diet. Treatment with an AT(1) receptor blocker, irbesartan, increased cholesterol content in bile and tended to increase cholesterol excretion into feces in ApoEKO mice with HCD.

SIGNIFICANCE

These results suggest that AT(1) and AT(2) receptor stimulation was involved in the regulation of cholesterol excretion into bile and feces, and that the regulation acted reciprocally in a cholesterol overload condition with HCD.