A nutrigenomic framework to identify time-resolving responses of hepatic genes in diet-induced obese mice

Comparative Whole-Transcriptome Profiling of Liver Tissue from Wistar Rats Fed with Diets Containing Different Amounts of Fat, Fructose, and Cholesterol

Differential expression of 30,003 genes was studied in the liver of female Wistar rats fed with isocaloric diets with the excess of fat, fructose, or cholesterol, or their combinations for 62 days using the method of whole-transcriptome profiling on a microchip. Relative mRNA expression levels of the Asah2, Crot, Crtc2, Fmo3, GSTA2, LOC1009122026, LOC102551184, NpY, NqO1, Prom1, Retsat, RGD1305464, Tmem104, and Whsc1 genes were also determined by RT-qPCR. All the tested diets affected differently the key metabolic pathways (KEGGs). Significant changes in the expression of steroid metabolism gene were observed in the liver of animals fed with the tested diets (except the high-fat high fructose diet). Both high-fat and high-fructose diets caused a significant decrease in the expression of squalene synthase (FDFT1 gene) responsible for the initial stage of cholesterol synthesis. On the contrary, in animals fed with the high-cholesterol diet (0.5% cholesterol), expression of the FDFT1 gene did not differ from the control group; however, these animals were characterized by changes in the expression of glucose and glycogen synthesis genes, which could lead to the suppression of glycogen synthesis and gluconeogenesis. At the same time, this group demonstrated different liver tissue morphology in comparison with the animals fed with the high-fructose high-fat diet, manifested as the presence of lipid vacuoles of a smaller size in hepatocytes. The high-fructose and high-fructose high-fat diets affected the metabolic pathways associated with intracellular protein catabolism (endocytosis, phagocytosis, proteasomal degradation, protein processing in the endoplasmic reticulum), tight junctions and intercellular contacts, adhesion molecules, and intracellular RNA transport. Rats fed with the high-fructose high-fat or high-cholesterol diets demonstrated consistent changes in the expression of the Crot, Prom1, and RGD1305464 genes, which reflected a coordinated shift in the regulation of lipid and carbohydrate metabolisms.

Sarcopoterium spinosum extract improved insulin sensitivity in mice models of glucose intolerance and diabetes

BACKGROUND

The glucose lowering properties of Sarcopoterium spinosum, a traditional medicinal plant, were previously validated by us using KK-Ay mice as a genetic model for type 2 diabetes (T2D).

OBJECTIVE

To clarify the effects of Sarcopoterium spinosum extract (SSE) on diet-induced glucose intolerance and to investigate SSE effects on carbohydrate and lipid metabolism in target tissues of both high-fat-diet (HFD)-fed and KK-Ay mice.

RESULTS

Mice were given SSE (70 mg/day) for 6 weeks. SSE improved glucose tolerance and insulin sensitivity in HFD-fed mice as was demonstrated previously in KK-Ay mice. Higher insulin sensitivity was validated by lower serum insulin and activation of the insulin signaling cascade in skeletal muscle and liver of SSE-treated mice in both models. H&E staining of the livers demonstrated lower severity of steatosis in SSE-treated mice. Several model-specific effects of SSE were observed-mRNA expression of proinflammatory genes and CD36 was reduced in SSE-treated KK-Ay mice. Hepatic mRNA expression of PEPCK was also reduced in SSE-treated KK-Ay mice, while other genes involved in carbohydrates and lipid metabolism were not affected. HFD-fed mice treated by SSE had elevated hepatic glycogen stores. Gluconeogenic gene expression was not affected, while GCK expression was increased. HFD-induced hepatic steatosis was not affected by SSE. However, while genes involved in lipid metabolism were downregulated by HFD, this was not found in HFD-fed mice given SSE, demonstrating an expression profile which is similar to that of standard diet-fed mice.

CONCLUSION

Our study supports the insulin sensitizing activity of SSE and suggests that this extract might improve other manifestations of the metabolic syndrome.

Rhizoma Coptidis alkaloids alleviate hyperlipidemia in B6 mice by modulating gut microbiota and bile acid pathways

It is hypothesized that Rhizoma Coptidis (RC) alkaloids exert their hypolipidemic effects primarily by targeting the gastrointestinal tract and liver. Thus, this study was conducted to evaluate the antihyperlipidemic mechanisms of RC alkaloids (at a daily dose of 140mg/kg for 35days) in high-fat and high-cholesterol induced hyperlipidemic B6 mice. After treatment, serum lipid parameters were determined, the expression of lipid metabolism related genes and pathways such as the sterol regulatory element binding proteins (SREBPs) and bile acid signaling in mice were also investigated. Meanwhile, Illumina sequencing was used to investigate the differences in gut microbiota of B6 mice. The results indicated that RC alkaloids reduced the body weight gain and serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), total bile acids (TBA) and lipopolysaccharide of B6 mice. Liver fat deposition and epididymal adipose cell size were also deceased in therapy group. RC alkaloids feeding significantly promoted the abundance of Sporobacter termitidis, Alcaligenes faecalis, Akkermansia muciniphila in the gut of mice, whereas, the abundance of Escherichia coli, Desulfovibrio C21_c20, Parabacteroides distasonis was suppressed. The observed antihyperlipidemic effects of RC alkaloids can also be attributed to their action as agonists of FXR and TGR5, activators for SREBP2, LDLR, UCP2 and CYP7A1, inhibitors of HMGCR, TXNIP, TLR4 and JNK. Therefore, this study expands current knowledge on hypolipidemic mechanisms of RC alkaloids and presents new evidence supporting a key role for RC alkaloids as regulators of lipid homeostasis by modulation gut microbiota and hepatic lipid metabolism.

Unraveling human protein interaction networks underlying co-occurrences of diseases and pathological conditions

Background

Human diseases frequently cause complications such as obesity-induced diabetes and share numbers of pathological conditions, such as inflammation, by dysfunctions of common functional modules, such as protein–protein interactions (PPIs).

Methods

Our developed pipeline, ICod (Interaction analysis for disease Comorbidity), grades similarities between pairs of disease-related PPIs including comorbid diseases and pathological conditions. ICod displayed a disease similarity network consisting of nodes of disease PPIs and edges of similarity value. As a proof of concept, eight complex diseases and pathological conditions, such as type 2 diabetes, obesity, inflammation, and cancers, were examined to discover whether PPIs shared between diseases were associated with comorbidities.

Results

By comparing Medicare reports of disease co-occurrences from 31 million patients, the disease similarity network shows that PPIs of pathological conditions, including insulin resistance, and inflammation, overlap significantly with PPIs of various comorbid diseases, including diabetes, obesity, and cancers (p < 0.05). Interestingly, maintaining connectivity between essential genes was more drastically perturbed by removing a node of a disease-related gene rather than a pathological condition-related gene, such as one related to inflammations.

Conclusion

Thus, PPIs of pathological symptoms are underlying functional modules across diseases accompanying comorbidity phenomena, whereas they contribute only marginally to maintaining interactions between essential genes.