Aberrant expression of HDL-bound microRNA induced by a high-fat diet in a pig model: implications in the pathogenesis of dyslipidaemia

New Perspectives on Crosstalks Between Bacterial Regulatory RNAs from Outer Membrane Vesicles and Eukaryotic Cells

Regulatory small RNAs (sRNAs) help the bacteria to survive harsh environmental conditions by posttranscriptional regulation of genes involved in various biological pathways including stress responses, homeostasis, and virulence. These sRNAs can be found carried by different membrane-bound vesicles like extracellular vesicles (EVs), membrane vesicles (MVs), or outer membrane vesicles (OMVs). OMVs provide myriad functions in bacterial cells including carrying a cargo of proteins, lipids, and nucleic acids including sRNAs. A few interesting studies have shown that these sRNAs can be transported to the host cell by membrane vesicles and can regulate the host immune system. Although there is evidence that sRNAs can be exported to host cells and sometimes can even cross the blood-brain barrier, the exact mechanism is still unknown. In this review, we investigated the new techniques implemented in various studies, to elucidate the crosstalks between bacterial cells and human immune systems by membrane vesicles carrying bacterial regulatory sRNAs.

Inulin-induced differences on serum extracellular vesicles derived miRNAs in dairy cows suffering from subclinical mastitis

MicroRNA (miRNA) profiles vary with the nutritional and pathological conditions of cattle. In this study, we aimed to investigate the effects of inulin supplement on miRNA profiles derived from serum extracellular vesicles (EVs). Our goal was to determine the differences in miRNA expressions and analyse the pathways in which they are involved. Based on the results of California mastitis test and milk somatic cell counts, ten lactating cows with subclinical mastitis were randomly divided into two groups: an inulin group and a control group (n = 5 in each group). The inulin group received a daily supplement of 300 g of inulin while the control group did not receive any supplementation. After a 5-week treatment period, serum-derived EV-miRNAs from each cow were isolated. High-throughput sequencing was conducted to identify differentially expressed miRNAs. GO and KEGG bioinformatics analysis was performed to examine the target genes of these differentially expressed miRNAs. The EV-RNA concentration and small RNA content were not affected by the inulin treatment. A total of 162 known miRNAs and 180 novel miRNAs were identified from 10 samples in the two groups. Among the known miRNAs, 23 miRNAs were found to be differentially expressed between the two groups, with 18 upregulated and five downregulated in the inulin group compared to the control group. Pathway analysis revealed the involvement of these differentially expressed miRNAs in the regulation of cell structure and function, lipid oxidation and metabolism, immunity and inflammation, as well as digestion and absorption of nutrients. Overall, our study provides a molecular-level explanation for the reported beneficial health effects of inulin supplementation in cows with subclinical mastitis.

Circulating lipoprotein-carried miRNome analysis reveals novel VLDL-enriched microRNAs that strongly correlate with the HDL-microRNA profile

Lipoproteins have been described as microRNAs (miRNAs) carriers. Unfortunately, the bibliography on this topic is scarce and shows a high variability between independent investigations. In addition, the miRNA profiles of the LDL and VLDL fractions have not been completely elucidated. Here, we profiled the human circulating lipoprotein-carried miRNome. Lipoprotein fractions (VLDL, LDL and HDL) were isolated from the serum of healthy subjects by ultracentrifugation and purified by size-exclusion chromatography. A panel of 179 miRNAs commonly expressed in circulation was evaluated in the lipoprotein fractions using quantitative real-time PCR (qPCR) assays. A total of 14, 4 and 24 miRNAs were stably detected in the VLDL, LDL and HDL fractions, respectively. VLDL- and HDL-miRNA signatures were highly correlated (rho 0.814), and miR-16-5p, miR-142-3p, miR-223-3p and miR-451a were among the top 5 expressed miRNAs in both fractions. miR-125a-5p, miR-335-3p and miR-1260a, were detected in all lipoprotein fractions. miR-107 and miR-221-3p were uniquely detected in the VLDL fraction. HDL showed the larger number of specifically detected miRNAs (n = 13). Enrichment in specific miRNA families and genomic clusters was observed for HDL-miRNAs. Two sequence motifs were also detected for this group of miRNAs. Functional enrichment analysis including the miRNA signatures from each lipoprotein fraction suggested a potential role in mechanistic pathways previously associated with cardiovascular disease: fibrosis, senescence, inflammation, immune response, angiogenesis, and cardiomyopathy. Collectively, our results not only support the role of lipoproteins as circulating miRNA carriers but also describe for the first time the role of VLDL as a miRNA transporter.

WGCNA Analysis of Important Modules and Hub Genes of Compound Probiotics Regulating Lipid Metabolism in Heat-Stressed Broilers

This study aimed to study compound probiotics’ (Lactobacillus casei, Lactobacillus acidophilus and Bifidobacterium) effects on production performance, lipid metabolism and meat quality in heat-stressed broilers. A total of 400 one-day-old AA broilers were randomly divided into four groups, each containing the same five replicates, with 20 broilers in each replicate. The control (21 °C) and experiment 2 were fed a basic corn−soybean meal diet. Experiment 1 (21 °C) and experiment 3 were fed a basic corn−soybean meal diet with 10 g/kg compound probiotics on days 7 and 28, respectively. The ambient temperature of experiment 2 and experiment 3 was increased to 30−32 °C (9:00−17:00) for 28−42 days, while the temperature for the other time was kept at 21 °C. The results showed that, compared with the control, the production performance and the content of high-density lipoprotein cholesterol in experiment 1 and triglyceride (TG) in experiment 2 increased (p < 0.05). Compared with experiment 2, TG decreased and the production performance increased in experiment 3 (p < 0.05). However, there was no significant change in meat quality indicators. Weighted gene co-expression network analysis (WGCNA) was used to analyze the intramuscular fat, abdominal fat and five blood lipid indicators. We found five related modules. Fatty acid biosynthesis, glycerolipid metabolism, and fat digestion and absorption were the pathways for KEGG enrichment. Additionally, NKX2-1, TAS2R40, PTH, CPB1, SLCO1B3, GNB3 and AQP7 may be the hub genes of compound probiotics regulating lipid metabolism in heat-stressed broilers. In conclusion, this study identified the key genes of compound probiotics regulating lipid metabolism and provided a theoretical basis for the poultry breeding industry to alleviate heat stress.

The Role of Changes in Cumulative Lipid Parameter Burden in the Pathogenesis of Type 2 Diabetes Mellitus: A Cohort Study of People Aged 35-65 Years in Rural China

PURPOSE

The main purpose of this study was to examine the effect of the cumulative exposure of blood lipid parameters on type 2 diabetes mellitus (T2DM). Another purpose was to explore whether the cumulative burden of blood lipid parameters plays a certain role in the pathogenesis of diet affecting T2DM.

PATIENTS AND METHODS

A total of 63 cases of diabetes occurred from 2017 to 2020, with an incidence density of 3.71 person-years. The dietary intake of the residents was obtained by using a dietary frequency questionnaire (FFQ). Cumulative lipid parameter burden was calculated according to the number of years (2016-2020) multiplied by total cholesterol (TC), high density lipoprotein (HDL), low density lipoprotein (LDL) and triglyceride (TG). A Cox proportional hazard model was used to estimate the effect of cumulative lipid burden on T2DM. A mediating analysis of accelerated failure time (AFT) was used to investigate the mediating effects of certain foods, the cumulative lipid parameter burden and T2DM.

RESULTS

A higher cumulative TG load corresponded to a higher risk of T2DM onset (P_trend =0.021). After adjusting for covariates, the highest quartile cumulative TG burden had a 3.462 times higher risk of T2DM than that in the lowest quartile (HR=3.462, 95% CI: 1.297-9.243). Moreover, a higher cumulative HDL load corresponded to a lower risk of T2DM onset (P_trend =0.006). After adjusting for covariates, the risk of T2DM was 0.314-fold lower in the highest quartile of cumulative HDL burden than that in the lowest quartile (HR=0.314, 95% CI: 0.131-0.753). Cumulative TG burden partially mediated the association between red meat and T2DM.

CONCLUSION

The increase in cumulative HDL burden and the decrease in cumulative HDL burden are related to the incidence of T2DM. Cumulative TG burden was shown to play a partial mediating role in the pathogenesis of red meat and diabetes.