Differential metabolic and hepatic transcriptome responses of two miniature pig breeds to high dietary cholesterol

An overview of the cholesterol metabolism and its proinflammatory role in the development of MASLD

Cholesterol is an essential lipid molecule in mammalian cells. It is not only involved in the formation of cell membranes but also serves as a raw material for the synthesis of bile acids, vitamin D, and steroid hormones. Additionally, it acts as a covalent modifier of proteins and plays a crucial role in numerous life processes. Generally, the metabolic processes of cholesterol absorption, synthesis, conversion, and efflux are strictly regulated. Excessive accumulation of cholesterol in the body is a risk factor for metabolic diseases such as cardiovascular disease, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD). In this review, we first provide an overview of the discovery of cholesterol and the fundamental process of cholesterol metabolism. We then summarize the relationship between dietary cholesterol intake and the risk of developing MASLD, and also the animal models of MASLD specifically established with a cholesterol-containing diet. In the end, the role of cholesterol-induced inflammation in the initiation and development of MASLD is discussed.

Dysregulation of Ceramide Metabolism Is Linked to Iron Deposition and Activation of Related Pathways in the Aorta of Atherosclerotic Miniature Pigs

The miniature pig is a suitable animal model for investigating human cardiovascular diseases. Nevertheless, the alterations in lipid metabolism within atherosclerotic plaques of miniature pigs, along with the underlying mechanisms, remain to be comprehensively elucidated. In this study, we aim to examine the alterations in lipid composition and associated pathways in the abdominal aorta of atherosclerotic pigs induced by a high-fat, high-cholesterol, and high-fructose (HFCF) diet using lipidomics and RNA-Seq methods. The results showed that the content and composition of aortic lipid species, particularly ceramide, hexosyl ceramide, lysophosphatidylcholine, and triglyceride, were significantly altered in HFCF-fed pigs. Meanwhile, the genes governing sphingolipid metabolism, iron ion homeostasis, apoptosis, and the inflammatory response were significantly regulated by the HFCF diet. Furthermore, C16 ceramide could promote iron deposition in RAW264.7 cells, leading to increased intracellular reactive oxygen species (ROS) production, apoptosis, and activation of the toll-like receptor 4 (TLR4)/nuclear Factor-kappa B (NF-қB) inflammatory pathway, which could be mitigated by deferoxamine. Our study demonstrated that dysregulated ceramide metabolism could increase ROS production, apoptosis, and inflammatory pathway activation in macrophages by inducing iron overload, thus playing a vital role in the pathogenesis of atherosclerosis. This discovery could potentially provide a new target for pharmacological therapy of cardiovascular diseases such as atherosclerosis.

Characteristics of Metabolites in the Development of Atherosclerosis in Tibetan Minipigs Determined Using Untargeted Metabolomics

BACKGROUND

Atherosclerosis (AS) is a chronic progressive disease caused by lipometabolic disorder. However, the pathological characteristics and mechanism of AS have not been fully clarified. Through high-fat and high-cholesterol diet induction, Tibetan minipigs can be used as the AS model animals, as they have a very similar AS pathogenesis to humans.

METHODS

In this study, we built an AS model of Tibetan minipigs and identified the differential abundance metabolites in the development of AS based on untargeted metabolomics.

RESULTS

We found that sphingolipid metabolism and glucose oxidation were obviously higher in the AS group and phenylalanine metabolism was reduced in the AS group. Moreover, in the development of AS, gluconolactone was enriched in the late stage of AS whereas biopterin was enriched in the early stage of AS.

CONCLUSIONS

Our research provides novel clues to investigate the metabolic mechanism of AS from the perspective of metabolomics.

Genome-Wide Characterization and Comparative Analyses of Simple Sequence Repeats among Four Miniature Pig Breeds

Simple Summary

Simple sequence repeats (SSRs) are present at high densities in regulatory elements, suggesting that they may affect gene function and phenotypic traits. Therefore, SSRs can be exploited in marker-assisted selection. In addition, they can be widely used as molecular markers to study genetic diversity, population structure, and evolution. While SSRs have been widely studied in many mammalian species, very little research has focused on genome-wide SSRs of miniature pigs, a small but special group of pigs that express the dwarf phenotype. Based on the SSR-enriched library building and sequencing, about 30,000 novel polymorphic SSRs for four miniature pig breeds were mapped to the Duroc pig reference genome. The four miniature pig breeds had different numbers and types of SSRs and distributions of repeat units. There were 2518 polymorphic SSRs in the intron or exon regions that were common to all four breeds and functional analyses revealed 17 genes that were associated with body size and other genes that were associated with growth and development. In conclusion, the SSRs detected in the miniature pigs in this study may provide useful genetic markers for the selection of farm animals and the polymorphic SSRs provide valuable insights into the determination of mature body size, as well as the immunity, growth and development of animals.

Abstract

Simple sequence repeats (SSRs) are commonly used as molecular markers in research on genetic diversity and discrimination among taxa or breeds because polymorphisms in these regions contribute to gene function and phenotypically important traits. In this study, we investigated genome-wide characteristics, repeat units, and polymorphisms of SSRs using sequencing data from SSR-enriched libraries created from Wuzhishan (WZS), Bama (BM), inbred Luchuan (LC) and Zangxiang (ZX) miniature pig breeds. The numbers and types of SSRs, distributions of repeat units and polymorphic SSRs varied among the four breeds. Compared to the Duroc pig reference genome, 2518 polymorphic SSRs were unique and common to all four breeds and functional annotation revealed that they may affect the coding and regulatory regions of genes. Several examples, such as FGF23, MYF6, IGF1R, and LEPROT, are associated with growth and development in pigs. Three of the polymorphic SSRs were selected to confirm the polymorphism and the corresponding alleles through fluorescence polymerase chain reaction (PCR) and capillary electrophoresis. Together, this study provides useful insights into the discovery, characteristics and distribution of SSRs in four pig breeds. The polymorphic SSRs, especially those common and unique to all four pig breeds, might affect associated genes and play important roles in growth and development.