Hepatic Transcriptome Reveals Potential Key Genes Contributing to Differential Milk Production.

BACKGROUND: Despite the widespread adoption of TMR or PMR and the formulas designed to sufficiently cover the cows' requirements, individual dairy cows' milk production varies significantly. The liver is one of the most important organs in cow lactation metabolism and plays an essential role in the initiation of lactation. OBJECTIVES: This study aimed to investigate the potential key genes in the liver contributing to the different milk production. METHODS: We enrolled 64 cows and assigned them to high or low milk yield (MY) groups according to their first 3 weeks of milk production. We performed RNAseq for 35 liver samples with 18 from prepartum and 17 from postpartum cows. RESULTS: The continuous milk yield observation showed a persistently higher milk yield in high MY cows than low MY cows in the first 3 weeks. High MY cows showed better feed conversion efficiency. We identified 795 differentially expressed genes (DGEs) in the liver of high MY cows compared with low MY cows, with up-regulated genes linked to morphogenesis and development pathways. Weighted gene co-expression network analysis (WGCNA) revealed four gene modules positively correlating with milk yield, and protein and lactose yield (p < 0.05). Using the intersected genes between the four gene modules and DEGs, we constructed the linear mixed-effects models and identified six hub genes positively associated and two hub genes negatively associated with milk yield (Coefficients > 0.25, p < 0.05). Random forest machine learning model training based on these eight hub genes could efficiently predict the milk yield (p < 0.001, R2 = 0.946). Interestingly, the expression patterns of these eight hub genes remained remarkably similar before and after parturition. CONCLUSIONS: The present study indicated the critical role of liver in milk production. Activated processes involved in morphogenesis and development in liver may contribute to the higher milk production. Eight hub genes identified in this study may provide genetic research materials for dairy cow breeding.

Physiological responses to a changing winter climate in an early spring-breeding amphibian.

Climate change is swiftly altering environmental winter conditions, leading to significant ecological impacts such as phenological shifts in many species. As a result, animals might face physiological mismatches due to longer or earlier activity periods and are at risk of being exposed to late spring freezes. Our study points for the first time to the complex physiological challenges that amphibians face as a result of changing thermal conditions due to winter climate change. We investigated the physiological responses to a period of warmer winter days and sudden spring freeze in the common toad (Bufo bufo) by acclimating them to 4°C or 8°C for 48 h or exposing them to 4°C or -2°C for 6 h, respectively. We assessed the daily energy demands, determined body condition and cold tolerance, explored the molecular responses to freezing through hepatic tissue transcriptome analysis, and measured blood glucose levels. Toads acclimated to higher temperatures showed a higher daily energy expenditure and a reduced cold tolerance suggesting faster depletion of energy stores and the loss of winter acclimation during warmer winters. Blood sugar levels were higher in frozen toads indicating the mobilization of cryoprotective glucose with freezing which was further supported by changed patterns in proteins related to glucose metabolism. Overall, our results emphasize that increased thermal variability incurs physiological costs that may reduce energy reserves and thus affect amphibian health and survival. This might pose a serious threat to breeding adults and may have subsequent effects at the population level.

Corticosteroid-Binding Globulin (SERPINA6) Consolidates Sexual Dimorphism of Adult Rat Liver.

Produced by the liver, corticosteroid-binding globulin (CBG) regulates the plasma distribution and actions of glucocorticoids. A sex difference in pituitary growth hormone secretion patterns established during puberty in rats results in increased hepatic CBG production and 2-fold higher plasma corticosterone levels in females. Glucocorticoids control hepatic development and metabolic activities, and we have therefore examined how disrupting the SerpinA6 gene encoding CBG influences plasma corticosterone dynamics, as well as liver gene expression in male and female rats before and after puberty. Comparisons of corticosterone plasma clearance and hepatic uptake in adult rats, with or without CBG, indicated that CBG limits corticosterone clearance by reducing its hepatic uptake. Hepatic transcriptomic profiling revealed minor sex differences (207 differentially expressed genes) and minimal effect of CBG deficiency in 30-day-old rats before puberty. While liver transcriptomes in 60-day-old males lacking CBG remained essentially unchanged, 2710 genes were differentially expressed in wild-type female vs male livers at this age. Importantly, ∼10% of these genes lost their sexually dimorphic expression in adult females lacking CBG, including those related to cholesterol biosynthesis, inflammation, and lipid and amino acid catabolism. Another 203 genes were altered by the loss of CBG specifically in adult females, including those related to xenobiotic metabolism, circadian rhythm, and gluconeogenesis. Our findings reveal that CBG consolidates the sexual dimorphism of the rat liver initiated by sex differences in growth hormone secretion patterns and provide insight into how CBG deficiencies are linked to glucocorticoid-dependent diseases.

Effect of dietary betaine supplementation on the liver transcriptome profile in broiler chickens under heat stress conditions.

OBJECTIVE: The objective of the present study was to investigate the effect of dietary betaine (BT) supplementation on the hepatic transcriptome profiles in broiler chickens raised under heat stress (HS) conditions. METHODS: A total of 180 (21-d-old) Ross 308 male broiler chicks were allotted to 1 of 3 treatment groups with 6 replicated cages in a completely randomized design. One group was kept under thermoneutral conditions at all times and was fed a basal diet (PC). Other 2 groups were exposed to a cyclic heat stress condition. One of the 2 groups under heat stress conditions was fed the basal diet as a negative control (NC), whereas the other group was fed the basal diet supplemented with 0.2% BT. All chickens were provided with diets and water ad libitum for 21 d. Following the experiment, the liver samples were collected for RNA sequencing analysis. RESULTS: Broiler chickens in NC and BT group had decreased (p<0.05) growth performance. In the transcriptome analysis, the number of differentially expressed genes were identified in the liver by HS conditions and dietary BT supplementation. In the comparison between NC and PC treatments, genes related to energy and nucleic acid metabolism, amino acid metabolism, and immune system were altered by HS, which support the reason why heat-stressed poultry had decreased growth performance. In the comparison between NC and BT treatments, genes related to lipid metabolism, carbohydrate metabolism, and immune system were differently expressed under HS conditions. CONCLUSION: HS negatively impacts various physiological processes, including DNA replication, metabolism of amino acids, lipids, and carbohydrates, and cell cycle progression in broiler chickens. Dietary BT supplementation, however, offers potential counteractive effects by modulating liver function, facilitating gluconeogenesis, and enhancing immune systems. These findings provide a basis for understanding molecular responses by HS and the possible benefits of dietary BT supplementation in broiler chickens exposed to HS.

Early transcriptome changes associated with western diet induced NASH in Ldlr-/- mice points to activation of hepatic macrophages and an acute phase response.

Background: Nonalcoholic fatty liver disease (NAFLD) is a global health problem. Identifying early gene indicators contributing to the onset and progression of NAFLD has the potential to develop novel targets for early therapeutic intervention. We report on the early and late transcriptomic signatures of western diet (WD)-induced nonalcoholic steatohepatitis (NASH) in female and male Ldlr-/- mice, with time-points at 1 week and 40 weeks on the WD. Control Ldlr-/- mice were maintained on a low-fat diet (LFD) for 1 and 40 weeks. Methods: The approach included quantitation of anthropometric and hepatic histology markers of disease as well as the hepatic transcriptome. Results: Only mice fed the WD for 40 weeks revealed evidence of NASH, i.e., hepatic steatosis and fibrosis. RNASeq transcriptome analysis, however, revealed multiple cell-specific changes in gene expression after 1 week that persisted to 40 weeks on the WD. These early markers of disease include induction of acute phase response (Saa1-2, Orm2), fibrosis (Col1A1, Col1A2, TGFß) and NASH associated macrophage (NAM, i.e., Trem2 high, Mmp12 low). We also noted the induction of transcripts associated with metabolic syndrome, including Mmp12, Trem2, Gpnmb, Lgals3 and Lpl. Finally, 1 week of WD feeding was sufficient to significantly induce TNFα, a cytokine involved in both hepatic and systemic inflammation. Conclusion: This study revealed early onset changes in the hepatic transcriptome that develop well before any anthropometric or histological evidence of NALFD or NASH and pointed to cell-specific targeting for the prevention of disease progression.

New insights into the impact of polystyrene micro/nanoplastics on the nutritional quality of marine jacopever (Sebastes schlegelii).

Microplastics (MPs) and nanoplastics (NPs) are ubiquitous in the marine environments due to the wide use and mismanagement of plastics. However, the effect of MPs/NPs on the nutrition quality of economic species is poorly understood, and their underlying mechanisms remained unclear. We therefore investigated the impacts of polystyrene MPs/NPs on the nutrition composition of marine jacopever Sebastes schlegelii from the perspective of assimilation and metabolism. Results showed that NPs reduced more nutrition quality than MPs. Despite no notable impact on intestinal microbiota function, MPs/NPs influenced the assimilation of fish through intestinal damage. Furthermore, NPs induced greater damage to hepatocyte metabolism than MPs, caused by hepatocyte uptake through membrane protein pumps/channels and clathrin/caveolin-mediated endocytosis for NPs, while through phagocytosis/pinocytosis for MPs. NPs triggered more cell apoptosis signals in Ferroptosis and FoxO signaling pathways than MPs, destroying mitochondria structure. Compared with MP treatments, a significant upregulation of genes (PRODH and SLC25A25A) associated with the electron transfer chain of mitochondria was detected in the NP treatments, influencing the tricarboxylic acid cycle and interfering with liver metabolism of proteins, fatty acid, glycerol phospholipids, and carbohydrates. This work provides new insights into the potential impacts of MPs/NPs on the quality and safety of seafood.

Influence of the concentrate inclusion level in a grass silage-based diet on hepatic transcriptomic profiles in Holstein-Friesian dairy cows in early lactation.

Excessive negative energy balance in early lactation is linked to an increased disease risk but may be mitigated by appropriate nutrition. The liver plays central roles in both metabolism and immunity. Hepatic transcriptomic profiles were compared between 3 dietary groups in each of 40 multiparous and 18 primiparous Holstein-Friesian cows offered isonitrogenous grass silage-based diets with different proportions of concentrates: (1) low concentrate (LC, 30% concentrate + 70% grass silage); (2) medium concentrate (MC, 50% concentrate + 50% grass silage), or (3) high concentrate (HC, 70% concentrate + 30% grass silage). Liver biopsies were taken from all cows at around 14 d in milk for RNA sequencing, and blood metabolites were measured. The sequencing data were analyzed separately for primiparous and multiparous cows using CLC Genomics Workbench V21 (Qiagen Digital Insights), focusing on comparisons between HC and LC groups. More differentially expressed genes (DEG) were seen between the primiparous cows receiving HC versus LC diets than for multiparous cows (597 vs. 497), with only 73 in common, indicating differential dietary responses. Multiparous cows receiving the HC diet had significantly higher circulating glucose and insulin-like growth factor-1 and lower urea than those receiving the LC diet. In response to HC, only the multiparous cows produced more milk. In these animals, bioinformatic analysis indicated expression changes in genes regulating fatty acid metabolism and biosynthesis (e.g., ACACA, ELOVL6, FADS2), increased cholesterol biosynthesis (e.g., CYP7A1, FDPS, HMGCR), downregulation in hepatic AA synthesis (e.g., GPT, GCLC, PSPH, SHMT2), and decreased expression of acute phase proteins (e.g., HP, LBP, SAA2). The primiparous cows on the HC diet also downregulated genes controlling AA metabolism and synthesis (e.g., CTH, GCLC, GOT1, ODC1, SHMT2) but showed higher expression of genes indicative of inflammation (e.g., CCDC80, IL1B, S100A8) and fibrosis (e.g., LOX, LUM, PLOD2). This potentially adverse response to a HC diet in physically immature animals warrants further investigation.

Hepatic transcriptomic analysis reveals that Hif1α/ldha signal is involved in the regulation of hypoxia stress in black rockfish Sebastes schlegelii.

Hypoxia has become a common problem for aquatic organisms due to the interaction of global climate change and human activity. Black rockfish inhabits rocky reefs in waters of Japan, Korea and China, whereas the limited hypoxia tolerance leads to mass mortality and great economic loss. In this study, high-throughput RNA-seq for transcriptomic analysis was used to investigate the hepatic response in black rockfish under hypoxia (critical oxygen tension, Pcrit; loss of equilibrium, LOE) and reoxygenation (recover normal dissolved oxygen 24 h, R24) to explore the mechanisms underlying hypoxia tolerance and adaptation. A total of 573,040,410 clean reads and 299 differentially expressed genes (DEGs) in total were obtained during hypoxia and reoxygenation. GO annotation and Kyoto Encyclopedia of Genes and Genomes analysis demonstrated that the DEGs are mainly enriched in the biochemical metabolic pathways and HIF-1 signaling pathways. Transcriptomic analysis also identified 18 DEGs associated with HIF-1 signaling pathway (hif1α, tf, epo, hmox, gult1, mknk2, ldha, pfkfb3, hkdc, aldoa) and biological process (hif2α, apoeb, bcl6, mr1, errfi1, slc38a4, igfbp1a, ap4m1) as further validated by quantitative real-time PCR. Moreover, hif1α was positively or negatively correlated with glucose (ldha, pfkfb3, hkdc, aldoa) and lipid (apoeb) metabolism-related genes. The mRNA level of hif1α was significantly up-regulated under acute hypoxia stress and obtained the higher values than hif2α. Meanwhile, hif1α recognized the hypoxia response element located in the promoter of ldha and directly bound to the promoter to transactivate ldha expression. These results indicated that black rockfish may mainly utilize glycolysis to maintain homeostasis, and hif1α facilities hypoxia tolerance by modulating ldha expression.

Dataset of RNA-Seq transcriptome of the fetal liver at day 83 of gestation associated with periconceptual maternal nutrition in beef heifers.

Herein, we present a dataset based on the RNA-Seq analysis of liver tissue from bovine female fetuses at day 83 of gestation. The findings were reported in the main article, "Periconceptual maternal nutrition affects fetal liver programming of energy- and lipid-related genes" [1]. These data were generated to investigate the effects of periconceptual maternal vitamin and mineral supplementation and rates of body weight gain on the transcript abundance of genes associated with fetal hepatic metabolism and function. To this end, crossbred Angus beef heifers (n = 35) were randomly assigned to 1 of 4 treatments in a 2 × 2 factorial design. The main effects tested were vitamin and mineral supplementation (VTM or NoVTM - at least 71 days pre-breeding to day 83 of gestation) and rate of weight gain (low (LG - 0.28 kg/d) or moderate (MG - 0.79 kg/d) - from breeding to day 83). The fetal liver was collected on day 83 ± 0.27 of gestation. After total RNA isolation and quality control, strand-specific RNA libraries were prepared and sequenced on the Illumina® NovaSeq 6000 platform to generate paired-end 150-bp reads. After read mapping and counting, differential expression analysis was performed with edgeR. We identified 591 unique differentially expressed genes across all six vitamin-gain contrasts (FDR ≤ 0.1). To our knowledge, this is the first dataset investigating the fetal liver transcriptome in response to periconceptual maternal vitamin and mineral supplementation and/or the rate of weight gain. The data described in this article provides genes and molecular pathways differentially programming liver development and function.

Alterations in hepatic transcriptome and cecum microbiota underlying potential ways to prevent early fatty liver in laying hens.

Fatty liver syndrome (FLS) is a kind of nutritional metabolic disease in laying hens. Revealing FLS pathogenesis during the early period is what really makes sense for the prevention or nutritional regulation strategies. In the study, 9 healthy or naturally occurring early FLS birds were screened based on visual inspection, liver index and morphologic analysis. Liver and fresh cecal content samples were collected. Then transcriptomic and 16S rRNA technologies are applied to investigate hepatic transcriptome and cecum microbiota composition. Unpaired Student t test and some omics methods were used for statistical analysis. Results showed higher liver weight and index were found in FLS group; morphologic analysis indicated that there existed more lipid droplets in the liver of birds with FLS. Based on DESeq2 analysis, there were 229 up- and 487 down-regulated genes in the FLS group, among which most genes related to de novo fatty acid synthesis were up-regulated such as acetyl-CoA carboxylase, fatty acid synthase, stearoyl-CoA desaturase, and ELOVL fatty acid elongase 6 (ELOVL6). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated that pathways associated with lipid metabolism and liver damage were affected. 16S rRNA sequencing analysis of cecum microbiota showed that there was a significant difference between the Con and FLS groups. LEfSe analysis revealed that the relative abundance of Coprococcus, Odoribacter, Collinsella, Turicibacter, YRC22, Enterococcus, Shigella, and Bifidobacterium were down-regulated in the FLS group, whereas the abundance of Bacteroides, Mucispirillum, Butyricicoccus, Campylobacter, Akkermansia, and Clostridium were up-regulated. The KEGG enrichment from differential microbiota suggested that some metabolism-related functions were altered to some extent. Taken together, during the developmental of early fatty liver of laying hens, lipogenesis was enhanced, whereas abnormal metabolism occurs not only in lipid transportation but also in hydrolysis, which caused structural damage to the liver organ. Moreover, the dysbiosis of the cecum microbiota occurred. All of these serve as targets or provide theoretical references for the development of probiotics for fatty liver prevention in laying hens.

Genome analysis reveals hepatic transcriptional reprogramming changes mediated by enhancers during chick embryonic development.

The liver undergoes a slow process for lipid deposition during chick embryonic period. However, the underlying physiological and molecular mechanisms are still unclear. Therefore, the aim of the current study was to reveal the epigenetic mechanism of hepatic transcriptional reprogramming changes based on the integration analysis of RNA-seq and H3K27ac labeled CUT&Tag. Results showed that lipid contents increased gradually with the embryonic age (E) 11, E15, and E19 based on morphological analysis of Hematoxylin-eosin and Oil Red O staining as well as total triglyceride and cholesterol detection. The hepatic protein level of SREBP-1c was higher in E19 when compared with that in E11 and E15, while H3K27ac and H3K4me2 levels declined from E11 to E19. Differential expression genes (DEGs) among these 3 embryonic ages were determined by transcriptome analysis. A total of 107 and 46 genes were gradually upregulated and downregulated respectively with the embryonic age. Meanwhile, differential H3K27ac occupancy in chromatin was investigated. But the integration analysis of RNA-seq and CUT&Tag data showed that the overlap genes were less between DEGs and target genes of differential peaks in the promoter regions. Further, some KEGG pathways enriched from target genes of typical enhancer were overlapped with those from DEGs in transcriptome analysis such as insulin, FoxO, MAPK signaling pathways which were related to lipid metabolism. DNA motif analysis identify 8 and 10 transcription factors (TFs) based on up and down differential peaks individually among E11, E15, and E19 stages where 7 TFs were overlapped including COUP-TFII, FOXM1, FOXA1, HNF4A, RXR, ERRA, FOXA2. These results indicated that H3K27ac histone modification is involved in the transcriptional reprogramming regulation during embryonic development, which could recruit TFs binding to mediate differential enhancer activation. Differential activated enhancer impels dynamic transcriptional reprogramming towards lipid metabolism to promote the occurrence of special phenotype of hepatic lipid deposition.

Hepatic transcriptome profiling according to growth rate reveals acclimation in metabolic regulatory mechanisms to cyclic heat stress in broiler chickens.

Climate change has numerous effects on poultry that result in welfare concerns and economic losses in agricultural industries. However, the mechanisms underlying the acclimation to heat stress in poultry have not been comprehensively defined. Therefore, identifying associated patterns of gene regulation and understanding the molecular mechanisms of acclimation to a warmer environment will provide insights into the acclimation system of broiler chickens. We profiled differentially expressed genes (DEGs) associated with differences in growth performance under heat stress conditions in the liver tissues of broilers based on RNA sequencing data. The DEGs were identified by comparison to the gene expression levels of broilers exhibiting average growth at 28 d of age (D28A) and D36A relative to those at D21A. In D36A, 507 and 312 DEGs were up- and downregulated, respectively, whereas 400 and 156 DEGs were up- and downregulated in D28A, respectively. Pathway enrichment analysis further revealed that "fatty acid degradation" and "heat shock protein expression" were upregulated in broilers exhibiting a higher growth and weight, whereas "cell cycle arrest" and "amino acid metabolism" were downregulated. Transcriptome profiling revealed that the acclimatized group supplied fat and energy from the liver to tissues through the breakdown of fatty acids. Furthermore, homeostasis was maintained via heat shock proteins and antioxidant enzymes. The characterized candidate genes and mechanisms associated with the response to heat stress might serve as a foundation for improving the ability of broilers to acclimatize under heat stress conditions.

Amelioration of hydrolyzed guar gum on high-fat diet-induced obesity: Integrated hepatic transcriptome and metabolome.

Hydrolyzed guar gum has gained attention as an anti-obesity agent; however, few studies have focused on its role in amelioration of hepatic-associated metabolic processes. Here, the anti-obesity effect of low molecular weight hydrolyzed guar gum (GMLP, 1-10 kDa) on high-fat diet (HFD)-fed C57BL/6 J mice was investigated via transcriptome and metabolome in liver. GMLP reduced body weight gain and hepatic lipid accumulation dose-dependently, regulated blood lipid levels, and improved liver damage in HFD-fed mice. Integrated transcriptome and metabolome indicated that GMLP mainly altered lipid metabolism pathways (glycerophospholipid metabolism, glycerolipid metabolism, and fatty acid degradation), reduced disease biomarkers of ethyl glucuronide and neopterin, and increased levels of choline, flavin adenine dinucleotide, and pantetheine metabolites. Real-time quantitative PCR showed that GMLP downregulated key genes involved in de novo lipogenesis and triacylglycerol synthesis, while promoting fatty acid oxidation and choline synthesis. This study provides a theoretical basis for GMLP treatment in future clinical applications.

Downregulation of CYP17A1 by 20-hydroxyecdysone: plasma progesterone and its vasodilatory properties.

Aim: To investigate the effect of 20-hydroxyecdysone on steroidogenic pathway genes and plasma progesterone, and its potential impact on vascular functions. Methods: Chimeric mice with humanized liver were treated with 20-hydroxyecdysone for 3 days, and hepatic steroidogenic pathway genes and plasma progesterone were measured by transcriptomics and GC-MS/MS, respectively. Direct effects on muscle and mesenteric arterioles were assessed by myography. Results: CYP17A1 was downregulated in 20-hydroxyecdysone-treated mice compared with untreated group (p = 0.04), with an insignificant increase in plasma progesterone. Progesterone caused vasorelaxation which was blocked by 60 mM KCl, but unaffected by nitric oxide synthase inhibition. Conclusion: In the short term, 20-hydroxyecdysone mediates CYP17A1 downregulation without a significant increase in plasma progesterone, which has a vasodilatory effect involving inhibition of voltage-dependent calcium channels, and the potential to enhance 20-hydroxyecdysone vasorelaxation.

Does chronic dietary exposure to the mycotoxin deoxynivalenol affect the porcine hepatic transcriptome when an acute-phase response is initiated through first or second-pass LPS challenge of the liver?

The sensitivity of pigs to deoxynivalenol (DON) might be increased by systemic inflammation (SI), which also has consequences for hepatic integrity. Liver lesions and a dys-regulated gene network might hamper hepatic handling and elimination of DON whereby the way of initiation of hepatic inflammation might play an additional role. First and second-pass exposure of the liver with LPS for triggering a SI was achieved by LPS infusion via pre- or post-hepatic venous route, respectively. Each infusion group was pre-conditioned either with a control diet (0.12 mg DON/kg diet) or with a DON-contaminated diet (4.59 mg DON/kg diet) for 4 wk. Liver transcriptome was evaluated at 195 min after starting infusions. DON exposure alone failed to modulate the mRNA expression significantly. However, pre- and post-hepatic LPS challenges prompted transcriptional responses in immune and metabolic levels. The mRNAs for B-cell lymphoma 2-like protein 11 as a key factor in apoptosis and IFN-γ released by T cells were clearly up-regulated in DON-fed group infused with LPS post-hepatically. On the other hand, mRNAs for nucleotide binding oligomerization domain containing 2, IFN-α and eukaryotic translation initiation factor 2α kinase 3 as ribosomal stress sensors were exclusively up-regulated in control pigs with pre-hepatic LPS infusion. These diverse effects were traced back to differences in TLR4 signalling.

Di-(2-ethylhexyl) phthalate-induced hepatotoxicity exacerbated type 2 diabetes mellitus (T2DM) in female pubertal T2DM mice.

Di-(2-ethylhexyl) phthalate (DEHP), one of the most common plasticizers, is closely associated with a high prevalence of pubertal type 2 diabetes mellitus (T2DM). Numerous studies have indicated that DEHP-induced metabolic toxicity exhibits sex differences. In this study, the sex differences in the effect of DEHP on pubertal T2DM (P-T2DM) mice, the susceptibility of female P-T2DM mice to DEHP-induced metabolic toxicity, and the underlying mechanisms were investigated. DEHP exposure exacerbated metabolic disorders in female P-T2DM mice. Factorial analysis showed that female P-T2DM mice were more sensitive to DEHP exposure than female normal mice and male P-T2DM mice. It was determined by integrated biomarker response results that female P-T2DM mice had higher risks of developing T2DM, metabolic disorders, cardiovascular events and hepatotoxicity than male P-T2DM mice. Moreover, hepatic transcriptome analysis emphasized the effects of DEHP on the expression of oxidative injury- and metabolic function-related genes. Western blotting indicated that DEHP activated Jun-N-terminal kinase (JNK) and impaired insulin sensitivity in the liver, which were the main causes of DEHP-exacerbated metabolic abnormalities in P-T2DM mice. Our study revealed that compared with normal mice and male P-T2DM mice, female P-T2DM mice tend to suffer from increased DEHP-induced metabolic toxicity, which was primarily attributed to hepatotoxicity.

Resolvin E1-ChemR23 Axis Regulates the Hepatic Metabolic and Inflammatory Transcriptional Landscape in Obesity at the Whole Genome and Exon Level.

Resolvin E1 (RvE1) is an immunoresolvent that is synthesized from eicosapentaenoic acid and can bind the receptor ERV1/ChemR23. We previously showed activation of the RvE1-ChemR23 axis improves hyperglycemia and hyperinsulinemia of obese mice; however, it remains unclear how RvE1 controls glucose homeostasis. Here we investigated hepatic metabolic and inflammatory transcriptional targets of the RvE1-ChemR23 axis using lean and obese wild type (WT) and ChemR23 knockout (KO) mice. We conducted an in-depth transcriptional study by preforming whole gene-level and exon-level analyses, which provide insight into alternative splicing variants and miRNA regulation. Compared to controls, WT and KO obese mice in the absence of RvE1 displayed similar gene-level profiles, which entailed dysregulated pathways related to glucose homeostasis. Notably, obese WT mice relative to lean controls showed a robust decrease in pathways related to the biosynthesis of unsaturated fatty acids. At the exon-level, obese ChemR23 KOs compared to obese WT mice displayed changes in pathways related to hepatic lipid transport, cholesterol metabolism, and immunological functions such as complement cascades and platelet activation. Importantly, upon RvE1 administration to WT obese mice, we discovered upregulated genes in pathways relating to insulin sensitivity and downregulated genes related to regulators of TGF-ß signaling. This transcriptional profile was generally not recapitulated with obese ChemR23 KO mice administered RvE1. Collectively, gene and exon-level analyses suggest RvE1 controls the hepatic transcriptional profile related to glucose homeostasis, insulin sensitivity, and inflammation in a manner that is largely dependent on ChemR23. These studies will drive future mechanistic experiments on the RvE1-ChemR23 axis.

Hepatic transcriptomic adaptation from prepartum to postpartum in dairy cows.

The transition from pregnancy to lactation is the most challenging period for high-producing dairy cows. The liver plays a key role in biological adaptation during the peripartum. Prior works have demonstrated that hepatic glucose synthesis, cholesterol metabolism, lipogenesis, and inflammatory response are increased or activated during the peripartum in dairy cows; however, those works were limited by a low number of animals used or by the use of microarray technology, or both. To overcome such limitations, an RNA sequencing analysis was performed on liver biopsies from 20 Holstein cows at 7 ± 5d before (Pre-P) and 16 ± 2d after calving (Post-P). We found 1,475 upregulated and 1,199 downregulated differently expressed genes (DEG) with a false discovery rate adjusted P-value < 0.01 between Pre-P and Post-P. Bioinformatic analysis revealed an activation of the metabolism, especially lipid, glucose, and amino acid metabolism, with increased importance of the mitochondria and a key role of several signaling pathways, chiefly peroxisome proliferators-activated receptor (PPAR) and adipocytokines signaling. Fatty acid oxidation and gluconeogenesis, with a likely increase in amino acid utilization to produce glucose, were among the most important functions revealed by the transcriptomic adaptation to lactation in the liver. Although gluconeogenesis was induced, data indicated decrease in expression of glucose transporters. The analysis also revealed high activation of cell proliferation but inhibition of xenobiotic metabolism, likely due to the liver response to inflammatory-like conditions. Co-expression network analysis disclosed a tight connection and coordination among genes driving biological processes associated with protein synthesis, energy and lipid metabolism, and cell proliferation. Our data confirmed the importance of metabolic adaptation to lipid and glucose metabolism in the liver of early Post-P cows, with a pivotal role of PPAR and adipocytokines.

Hepatic Transcriptome Analysis Revealing the Molecular Pathogenesis of Type 2 Diabetes Mellitus in Zucker Diabetic Fatty Rats.

Around 9% of the adult population in the world (463 million) suffer from diabetes mellitus. Most of them (~90%) belong to type 2 diabetes mellitus (T2DM), which is a common chronic metabolic disorder, and the number of cases has been reported to increase each year. Zucker diabetic fatty (ZDF) rat provides a successful animal model to study the pathogenesis of T2DM. Although previous hepatic transcriptome studies revealed some novel genes associated with the occurrence and development of T2DM, there still lacks the comprehensive transcriptomic analysis for the liver tissues of ZDF rats. We performed comparative transcriptome analyses between the liver tissues of ZDF rats and healthy ZCL rats and also evaluated several clinical indices. We could identify 214 and 104 differentially expressed genes (DEGs) and lncRNAs in ZDF rats, respectively. Pathway and biofunction analyses showed a synergistic effect between mRNAs and lncRNAs. By comprehensively analyzing transcriptomic data and clinical indices, we detected some typical features of T2DM in ZDF rats, such as upregulated metabolism (significant increased lipid absorption/transport/utilization, gluconeogenesis, and protein hydrolysis), increased inflammation, liver injury and increased endoplasmic reticulum (ER) stress. In addition, of the 214 DEGs, 114 were known and 100 were putative T2DM-related genes, most of which have been associated with substance metabolism (particularly degradation), inflammation, liver injury and ER stress biofunctions. Our study provides an important reference and improves understanding of molecular pathogenesis of obesity-associated T2DM. Our data can also be used to identify potential diagnostic markers and therapeutic targets, which should strengthen the prevention and treatment of T2DM.

Modulation of the Gut Microbiota during High-Dose Glycerol Monolaurate-Mediated Amelioration of Obesity in Mice Fed a High-Fat Diet.

Obesity and associated metabolic disorders are worldwide public health issues. The gut microbiota plays a key role in the pathophysiology of diet-induced obesity. Glycerol monolaurate (GML) is a widely consumed food emulsifier with antibacterial properties. Here, we explore the anti-obesity effect of GML (1,600 mg/kg of body weight) in high-fat diet (HFD)-fed mice. HFD-fed mice were treated with 1,600 mg/kg GML. Integrated microbiome, metabolome, and transcriptome analyses were used to systematically investigate the metabolic effects of GML, and antibiotic treatment was used to assess the effects of GML on the gut microbiota. Our data indicated that GML significantly reduced body weight and visceral fat deposition, improved hyperlipidemia and hepatic lipid metabolism, and ameliorated glucose homeostasis and inflammation in HFD-fed mice. Importantly, GML modulated HFD-induced gut microbiota dysbiosis and selectively increased the abundance of Bifidobacterium pseudolongum Antibiotic treatment abolished all the GML-mediated metabolic improvements. A multiomics (microbiome, metabolome, and transcriptome) association study showed that GML significantly modulated glycerophospholipid metabolism, and the abundance of Bifidobacterium pseudolongum strongly correlated with the metabolites and genes that participated in glycerophospholipid metabolism. Our results indicated that GML may be provided for obesity prevention by targeting the gut microbiota and regulating glycerophospholipid metabolism.