High fat diet and associated changes in the expression of micro-RNAs in tissue: Lessons learned from animal studies

A Study on the Amelioration of Circadian Rhythm Disorders in Fat Mice Using High-Protein Diets

This innovative study investigates the effects of high-protein diets (milk protein) on the circadian rhythm of hepatic lipid metabolism. We aimed to understand how high-protein interventions regulate biological clock genes, maintain lipid metabolism balance, and affect the circadian rhythm of antioxidant levels in vivo. We divided 120 SPF-class C57BL/6J mice into the control, high-fat/low-protein (HF-LP), and high-fat/high-protein (HF-HP) groups. Mice were sacrificed during active (2 a.m. and 8 a.m.) and rest periods (2 p.m. and 8 p.m.). In the HF-LP group, hepatic lipid anabolic enzymes were consistently expressed at high levels, while key lipolytic enzymes slowly increased after feeding with no significant diurnal differences. This led to an abnormal elevation in blood lipid levels, a slow increase in and low levels of superoxide dismutase, and a rapid increase in malondialdehyde levels, deviating from the diurnal trend observed in the control group. However, high-protein interventions in the HF-HP group restored lipid synthase activity and the expression of key catabolic enzymes, exhibiting a precise circadian rhythm. It also improved the lipid-metabolism rhythm, which was disrupted by the high-fat diet. Overall, high-protein interventions restored the expression of key enzymes involved in lipid metabolism, improving the lipid-metabolism rhythm, which was disrupted by the high-fat diet.

Mechanistic insights into dietary (poly)phenols and vascular dysfunction-related diseases using multi-omics and integrative approaches: Machine learning as a next challenge in nutrition research

Dietary (poly)phenols have been extensively studied for their vasculoprotective effects and consequently their role in preventing or delaying onsets of cardiovascular and metabolic diseases. Even though early studies have ascribed the vasculoprotective properties of (poly)phenols primarily on their putative free radical scavenging properties, recent data indicate that in biological systems, (poly)phenols act primarily through genomic and epigenomic mechanisms. The molecular mechanisms underlying their health properties are still not well identified, mainly due to the use of physiologically non-relevant conditions (native molecules or extracts at high concentrations, rather than circulating metabolites), but also due to the use of targeted genomic approaches aiming to evaluate the effect only on few specific genes, thus preventing to decipher detailed molecular mechanisms involved. The use of state-of-the-art untargeted analytical methods represents a significant breakthrough in nutrigenomics, as these methods enable detailed insights into the effects at each specific omics level. Moreover, the implementation of multi-omics approaches allows integration of different levels of regulation of cellular functions, to obtain a comprehensive picture of the molecular mechanisms of action of (poly)phenols. In combination with bioinformatics and the methods of machine learning, multi-omics has potential to make a huge contribution to the nutrition science. The aim of this review is to provide an overview of the use of the omics, multi-omics, and integrative approaches in studying the vasculoprotective properties of dietary (poly)phenols and address the potentials for use of the machine learning in nutrigenomics.

A high-calorie diet aggravates LPS-induced pneumonia by disturbing the gut microbiota and Th17/Treg balance

The intestinal flora plays an important role in the inflammatory response to the systemic or local infections in the host. A high-calorie diet has been shown to aggravate pneumonia and delay recovery, especially in children. However, the underlying mechanisms remain unclear. Our previous studies demonstrated that a high-calorie diet and LPS atomization synergistically promoted lung inflammation injury in juvenile rats. In this study, specific pathogen-free juvenile rats were placed in a routine environment, and subjected to a high-calorie diet or LPS atomization in isolation as well as combination. Our data revealed that LPS nebulization combined with a high-calorie diet resulted in significant changes in rats, such as slow weight gain, increased lung index, and aggravated lung inflammatory damage. Meanwhile, we found that the aggravation of LPS-induced pneumonia by a high-calorie diet disturbs the balance of Th17/Treg cells. Furthermore, high-throughput sequencing of intestinal contents revealed that a high-calorie diet changed the gut microbiome composition, decreased microbial diversity, and particularly reduced the abundance of the intestinal microbiota associated with the production of short-chain fatty acids (SCFAs) in rats. Consequently, the levels of SCFAs, especially acetate, propionate, and butyrate, were significantly decreased following the intervention of a high-calorie diet. More critically, the effects of a high-calorie diet were shown to be transmissible among pneumonia rats through cohousing microbiota transplantation. Taken together, we provide evidence to support that a high-calorie diet can potentially reset the gut microbiome and metabolites, disrupt Th17/Treg cell balance and immune homeostasis, and aggravate LPS-induced lung inflammatory damage, which may provide a new perspective on the pathogenesis of lung inflammation injury, and suggest a novel microbiota-targeting therapy for inflammatory lung diseases.

An obesogenic maternal environment impairs mouse growth patterns, satellite cell activation, and markers of postnatal myogenesis

Skeletal muscle is sensitive to environmental cues that are first present in utero. Maternal overnutrition is a model of impaired muscle development leading to structural and metabolic dysfunction in adult life. In this study, we investigated the effect of an obesogenic maternal environment on growth and postnatal myogenesis in the offspring. Male C57BL/6J mice born to chow- or high-fat-diet-fed mothers were allocated to four different groups at the end of weaning. For the following 10 wk, half of the pups were maintained on the same diet as their mother and half of the pups were switched to the other diet (chow or high-fat). At 12 wk of age, muscle injury was induced using an intramuscular injection of barium chloride. Seven days later, mice were humanely killed and muscle tissue was harvested. A high-fat maternal diet impaired offspring growth patterns and downregulated satellite cell activation and markers of postnatal myogenesis 7 days after injury without altering the number of newly synthetized fibers over the whole 7-day period. Importantly, a healthy postnatal diet could not reverse any of these effects. In addition, we demonstrated that postnatal myogenesis was associated with a diet-independent upregulation of three miRNAs, mmu-miR-31-5p, mmu-miR-136-5p, and mmu-miR-296-5p. Furthermore, in vitro analysis confirmed the role of these miRNAs in myocyte proliferation. Our findings are the first to demonstrate that maternal overnutrition impairs markers of postnatal myogenesis in the offspring and are particularly relevant to today's society where the incidence of overweight/obesity in women of childbearing age is increasing.

Coordinated alteration of mRNA-microRNA transcriptomes associated with exosomes and fatty acid metabolism in adipose tissue and skeletal muscle in grazing cattle

Objective

On the hypothesis that grazing of cattle prompts organs to secrete or internalize circulating microRNAs (c-miRNAs) in parallel with changes in energy metabolism, we aimed to clarify biological events in adipose, skeletal muscle, and liver tissues in grazing Japanese Shorthorn (JSH) steers by a transcriptomic approach.

Methods

The subcutaneous fat (SCF), biceps femoris muscle (BFM), and liver in JSH steers after three months of grazing or housing were analyzed using microarray and quantitative polymerase chain reaction (qPCR), followed by gene ontology (GO) and functional annotation analyses.

Results

The results of transcriptomics indicated that SCF was highly responsive to grazing compared to BFM and liver tissues. The ‘Exosome’, ‘Carbohydrate metabolism’ and ‘Lipid metabolism’ were extracted as the relevant GO terms in SCF and BFM, and/or liver from the >1.5-fold-altered mRNAs in grazing steers. The qPCR analyses showed a trend of upregulated gene expression related to exosome secretion and internalization (charged multivesicular body protein 4A, vacuolar protein sorting-associated protein 4B, vesicle associated membrane protein 7, caveolin 1) in the BFM and SCF, as well as upregulation of lipolysis-associated mRNAs (carnitine palmitoyltransferase 1A, hormone-sensitive lipase, perilipin 1, adipose triglyceride lipase, fatty acid binding protein 4) and most of the microRNAs (miRNAs) in SCF. Moreover, gene expression related to fatty acid uptake and inter-organ signaling (solute carrier family 27 member 4 and angiopoietin-like 4) was upregulated in BFM, suggesting activation of SCF-BFM organ crosstalk for energy metabolism. Meanwhile, expression of plasma exosomal miR-16a, miR-19b, miR-21-5p, and miR-142-5p was reduced. According to bioinformatic analyses, the c-miRNA target genes are associated with the terms ‘Endosome’, ‘Caveola’, ‘Endocytosis’, ‘Carbohydrate metabolism’, and with pathways related to environmental information processing and the endocrine system.

Conclusion

Exosome and fatty acid metabolism-related gene expression was altered in SCF of grazing cattle, which could be regulated by miRNA such as miR-142-5p. These changes occurred coordinately in both the SCF and BFM, suggesting involvement of exosome in the SCF-BFM organ crosstalk to modulate energy metabolism.

Dietary compounds as potential modulators of microRNA expression in psoriasis

Nutrigenomic DNA reprogramming in different chronic diseases and cancer has been assessed through the stimulation of gene expression and mRNA synthesis versus DNA silencing by CpG DNA modification (methylation); histone modification (acetylation, methylation) and expression of small noncoding RNAs, known as microRNAs (miRNAs). With regard to the specific nutrigenomic effects in psoriasis, the influence of specific diets on inflammatory cell signaling transcriptional factors such as nuclear factor (NF)-κB and Wnt signaling pathways, on disease-related specific cytokine expression, pro/antioxidant balance, keratinocyte proliferation/apoptosis and on proliferation/differentiation ratio have been documented; however, the influence of dietary compounds on the balance between 'good and bad' miRNA expression has not been considered. This review aims to summarize knowledge about aberrant microRNAs expression in psoriasis and to emphasize the potential impact of some dietary compounds on endogenous miRNA synthesis in experimental conditions in vivo and in vitro. Among the aberrantly expressed miRNAs in psoriasis, one of the most prominently upregulated seems to be miR-21. The beneficial effects of phenolic compounds (curcumin and resveratrol), vitamin D, methyl donors, and omega-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid) are discussed. Highly expressed miR-155 has been downregulated by flavonoids (through a quercetin-rich diet) and by vitamin D. Quercetin has been effective in modulating miR-146a. On the other hand, downregulated miR-125b expression was restored by vitamin D, Coenzyme Q10 and by microelement selenium. In conclusion, the miRNA profile, together with other 'omics', may constitute a multifaceted approach to explore the impact of diet on psoriasis prevention and treatment.

Postprandial Circulating miRNAs in Response to a Dietary Fat Challenge

Postprandial lipemia has many physiopathological effects, some of which increase the risk of cardiovascular disease. MicroRNAs (miRNAs) can be found in almost all biological fluids, but their postprandial kinetics are poorly described. We aimed to profile circulating miRNAs in response to a fat challenge. In total, 641 circulating miRNAs were assessed by real-time PCR in plasmas from mice two hours after lipid gavage. Mice with intestine-specific loss of Dicer were screened to identify potential miRNAs released by the intestine. A total of 68 miRNAs were selected for further validation. Ten circulating miRNAs were finally validated as responsive to postprandial lipemia, including miR-206-3p, miR-543-3p, miR-466c-5p, miR-27b-5p, miR-409-3p, miR-340-3p, miR-1941-3p, miR-10a-3p, miR-125a-3p, and miR-468-3p. Analysis of their possible tissues of origin/target showed an enrichment of selected miRNAs in liver, intestine, brain, or skeletal muscle. miR-206, miR-27b-5p, and miR-409-3p were validated in healthy humans. Analysis of their predicted target genes revealed their potential involvement in insulin/insulin like growth factor (insulin/IGF), angiogenesis, cholecystokinin B receptor signaling pathway (CCKR), inflammation or Wnt pathways for mice, and in platelet derived growth factor (PDGF) and CCKR signaling pathways for humans. Therefore, the current study shows that certain miRNAs are released in the circulation in response to fatty meals, proposing them as potential novel therapeutic targets of lipid metabolism.

Customized Dietary Intervention Avoids Unintentional Weight Loss and Modulates Circulating miRNAs Footprint in Huntington's Disease

SCOPE

Huntington's disease (HD) is a rare progressive neurodegenerative disorder of genetic origin, with no definitive treatment. Unintentional weight loss (UWL) is a clinical feature of symptomatic HD subjects. To prevent UWL, a customized HD diet is designed and its impact on plasma miRNA HD footprint and neurological parameters is examined.

METHODS AND RESULTS

Eleven participants are included, BMI ≤ 18 kg m^-2 or UWL of 5% in 6 months or 10% in a year. Diet design is based on nutritional surveys and interviews of participants and caregivers and on published literature review. Twelve-month dietary intervention, with follow-up every 3 months, induces high diet adherence, which manages to curb UWL in all participants (73% gained weight). Noticeable increases in fat mass and leptin levels are obtained. The results also show significant decrease in the expression of 19 miRNAs, which are previously reported to be upregulated in HD-patients versus healthy controls: revealing hsa-miR-338-3p, hsa-miR-128-3p, hsa-miR-23a-3p, and hsa-miR-24-3p as potential HD-biomarkers. The diminished expression of hsa-miR-100-5p reflects the general maintenance of the functional status. Cognitive status is improved in six of 11 participants, while only three present better motor-score values.

CONCLUSION

A customized HD-diet prevents UWL and modified miRNAs HD-footprint. The normalization of miRNA values suggests its potentially use as HD-biomarkers.

Modeling the Western Diet for Preclinical Investigations

Rodent models have been invaluable for biomedical research. Preclinical investigations with rodents allow researchers to investigate diseases by using study designs that are not suitable for human subjects. The primary criticism of preclinical animal models is that results are not always translatable to humans. Some of this lack of translation is due to inherent differences between species. However, rodent models have been refined over time, and translatability to humans has improved. Transgenic animals have greatly aided our understanding of interactions between genes and disease and have narrowed the translation gap between humans and model animals. Despite the technological innovations of animal models through advances in genetics, relatively little attention has been given to animal diets. Namely, developing diets that replicate what humans eat will help make animal models more relevant to human populations. This review focuses on commonly used rodent diets that are used to emulate the Western dietary pattern in preclinical studies of obesity and type 2 diabetes, nonalcoholic liver disease, maternal nutrition, and colorectal cancer.

Effects of Conjugated Linoleic Acid Supplementation on the Expression Profile of miRNAs in Porcine Adipose Tissue

Conjugated linoleic acids (CLAs) play a major role in adipocyte differentiation and lipid metabolism in animals. MicroRNAs (miRNAs) appear to be involved in many biological processes in adipose tissue. However, the specific influence on miRNAs by CLA supplementation in porcine adipose tissue remains unclear. Thus, we continuously added 1.5% CLA to the pig diet from the embryo stage to the finishing period and conducted a high-throughput sequencing approach to analyse the changes in adipose tissue miRNAs. We identified 283 known porcine miRNAs, and 14 miRNAs were differentially expressed in response to CLA treatment. A Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the targets of the 14 differentially expressed miRNAs were involved in the Wnt signalling pathway. The CLA treatment downregulated the gene expression of PPARγ, C/EBPα, FAS, and FATP1 in both subcutaneous and abdominal fat tissues; the analysis showed that ssc-miR-21 expression was significantly correlated with PPARγ expression (p < 0.05), and speculated that ssc-miR-21 might influence adipogenesis through PPARγ. In conclusion, our study analysed the miRNA profiles in porcine adipose tissues by CLA treatment, and demonstrated that miRNAs are important regulators of fat lipogenesis. This study provides valuable information for the molecular regulatory mechanism of CLA on adipose tissue.

Anthocyanins from Purple Corn Ameliorated Tumor Necrosis Factor-α-Induced Inflammation and Insulin Resistance in 3T3-L1 Adipocytes via Activation of Insulin Signaling and Enhanced GLUT4 Translocation

SCOPE

The aim was to compare the effect of an anthocyanin-rich extract from purple corn pericarp (PCW) and pure anthocyanins on adipogenesis, inflammation, and insulin resistance in 3T3-L1 adipocytes on basal and inflammatory conditions.

METHODS AND RESULTS

Preadipocytes (3T3-L1) were treated during differentiation with or without PCW. Differentiated adipocytes were treated either individually or in combination with tumor necrosis factor α (TNF-α) and PCW, or pure C3G, Pr3G, P3G. PCW reduced preadipocyte differentiation (IC₅₀ = 0.4 mg/mL). PCW and pure anthocyanins including C3G reduced fatty acid synthase enzymatic activity. PCW reduced TNF-α-dependent inflammatory status increasing adiponectin (39%), and decreasing leptin (-79%). PCW and C3G increased glucose uptake and reduced reactive oxygen species generation in insulin resistant adipocytes. An increase in phosphorylation was observed in AKT, IKK, and MEK, and a decrease in IRS and mTOR activating the insulin receptor-associated pathway. PCW (7.5-fold) and C3G (6.3-fold) enhanced GLUT4 membrane translocation compared to insulin resistant adipocytes.

CONCLUSION

Anthocyanins from colored corn prevented adipocyte differentiation, lipid accumulation, and reduced PPAR-γ transcriptional activity on adipocytes in basal conditions. Ameliorated TNF-α-induced inflammation and insulin resistance in adipocytes via activation of insulin signaling and enhanced GLUT4 translocation suggesting a reduced hyperglycemia associated with the metabolic syndrome.