miR‐142‐5P regulates triglyceride by targeting CTNNB1 in goat mammary epithelial cells

MiR-2284b regulation of α-s1 casein synthesis in mammary epithelial cells of dairy goats

The lactation character of dairy goats is the most important characteristic, and milk protein is an important index to evaluate milk quality. Casein accounts for more than 80% of the total milk protein in goat milk and is the main component of milk protein. Using GMECs (goat mammary epithelial cells) as the research object, the CHECK2 vector of the CSN1S1 gene and the overexpression vector of pcDNA 3.1 were constructed, and the mimics of miR-2284b and the interfering RNA of CSN1S1 were synthesized. Using PCR, RT-qPCR, a dual luciferase activity detection system, EdU, CCK8, cell apoptosis detection and ELISA detection, we explored the regulatory mechanism and molecular mechanism of miR-2284b regulation of αs1-casein synthesis in GMECs. miR-2284b negatively regulates proliferation and apoptosis of GMECs and αs1-casein synthesis. Two new gene sequences of CSN1S1 were discovered. CSN1S1-1/-2 promoted the proliferation of GMECs and inhibited cell apoptosis. However, it had no effect on αs1-casein synthesis. MiR-2284b negatively regulates αs1-casein synthesis in GMECs by inhibiting the CSN1S1 gene. These results all indicated that miR-2284b could regulate αs1-casein synthesis, thus playing a theoretical guiding role in the future breeding process of dairy goats and accelerating the development of dairy goat breeding.

MiRNome variations in milk fractions during feed restrictions of different intensities in dairy cows

BACKGROUND

In dairy cows, diet is one factor that can affect their milk production and composition. However, the effect of feed restriction on milk miRNome has not yet been described. Indeed, milk is the body fluid with the highest RNA concentration, which includes numerous microRNA. Its presence in the four different milk fractions, whole milk, fat globules, mammary epithelial cells and extracellular vesicles, is still poorly documented. This study aimed to describe the effects of different feed restrictions on the miRNome composition of different milk fractions.

RESULTS

Two feed restrictions were applied to lactating dairy cows, one of high intensity and one of moderate intensity. 2,896 mature microRNA were identified in the different milk fractions studied, including 1,493 that were already known in the bovine species. Among the 1,096 microRNA that were sufficiently abundant to be informative, the abundance of 1,027 of them varied between fractions: 36 of those were exclusive to one milk fraction. Feed restriction affected the abundance of 155 microRNA, with whole milk and milk extracellular vesicles being the most affected, whereas milk fat globules and exfoliated mammary epithelial cells were little or not affected at all. The high intensity feed restriction led to more microRNA variations in milk than moderate restriction. The target prediction of known microRNA that varied under feed restriction suggested the modification of some key pathways for lactation related to milk fat and protein metabolisms, cell cycle, and stress responses.

CONCLUSIONS

This study highlighted that the miRNome of each milk fraction is specific, with mostly the same microRNA composition but with variations in abundance between fractions. These specific miRNomes were affected differently by feed restrictions, the intensity of which appeared to be a major factor modulating milk miRNomes. These findings offer opportunities for future research on the use of milk miRNA as biomarkers of energy status in dairy cows, which is affected by feed restrictions.

Progress in epigenetic regulation of milk synthesis, with particular emphasis on mRNA regulation and DNA methylation

Inadequate milk secretion and a lack of nutrients in humans and mammals are serious problems. It is of great significance to clarify the mechanisms of milk synthesis and treatment methods. Epigenetic modification, represented by RNA methylation, is an important way of gene expression regulation that profoundly affects human gene expression and participates in various physiological and pathological mechanisms. Epigenetic disorders also have an important impact on the production and secretion of milk. This review systematically summarized the research results of epigenetics in the process of lactation in PubMed, Web of Science, NSTL, and other databases and reviewed the effects of epigenetics on human and mammalian lactation, including miRNAs, circRNAs, lncRNAs, DNA methylations, and RNA methylations. The abnormal expression of miRNAs was closely related to the synthesis and secretion of milk fat, milk protein, and other nutrients in the milk of cattle, sheep, and other mammals. MiRNAs are also involved in the synthesis of human milk and the secretion of nutrients. CircRNAs and lncRNAs mainly target miRNAs and regulate the synthesis of nutrients in milk by ceRNA mechanisms. The abnormal expression of DNA and RNA methylation also has an important impact on milk synthesis. Epigenetic modification has the potential to regulate the milk synthesis of breast epithelial cells. Analyzing the mechanisms of human and mammalian milk secretion deficiency and nutrient deficiency from the perspective of epigenetics will provide a new perspective for the treatment of postpartum milk deficiency in pregnant women and mammalian milk secretion deficiency.

circIFT80 Functions as a ceRNA for miR-142, miR-568, and miR-634 and Promotes the Progression of Colorectal Cancer by Targeting β-Catenin

Colorectal cancer (CRC) is the third most common form of malignant tumor and is characterized by high rates of proliferation and metastases. Circular RNAs (circRNAs) are a form of noncoding and closed loop RNA molecules and play vital roles in the progression of various types of cancer in humans. Here, we used circRNA microarray sequencing technology to analyze the different circRNAs between CRC tissues and normal tissues and explore the role of circIFT80 in progression of colorectal cancer. In this present study, we found that circIFT80 was abnormally overexpression in colorectal cancer tissues and tumor cells. While knockout circIFT80 in HT29 cell or SW480 cells, the proliferation, and migration of the cells were inhibited, the cell cycle was arrested in G2/M phase, and the cell apoptosis was increased. And then, we found circIFT80-positive correlation with CTNNB1 (β-catenin) by sponging miR-142, miR-568, and miR-634 upregulated the gene expression. These miRNAs which targeted β-catenin mRNA were confirmed by dual-luciferase reporter system and RNA-pulldown. In addition, xenograft tumor experiments showed that circIFT80 accelerated the tumorigenesis of CRC in vivo. In conclusion, our work reveals the impacts of circIFT80 as ceRNA in the progression of CRC, by which sponging miR-142, miR-568, and miR-634 enhanced the expression levels of β-catenin and activation Wnt/β-catenin pathway. Collectively, our data indicate that circIFT80 serves as an oncogene in CRC and represents a novel candidate for diagnosis and treatment.

The Role of microRNAs in the Mammary Gland Development, Health, and Function of Cattle, Goats, and Sheep

Milk is an integral and therefore complex structural element of mammalian nutrition. Therefore, it is simple to conclude that lactation, the process of producing milk, is as complex as the mammary gland, the organ responsible for this biochemical activity. Nutrition, genetics, epigenetics, disease pathogens, climatic conditions, and other environmental variables all impact breast productivity. In the last decade, the number of studies devoted to epigenetics has increased dramatically. Reports are increasingly describing the direct participation of microRNAs (miRNAs), small noncoding RNAs that regulate gene expression post-transcriptionally, in the regulation of mammary gland development and function. This paper presents a summary of the current state of knowledge about the roles of miRNAs in mammary gland development, health, and functions, particularly during lactation. The significance of miRNAs in signaling pathways, cellular proliferation, and the lipid metabolism in agricultural ruminants, which are crucial in light of their role in the nutrition of humans as consumers of dairy products, is discussed.

Circ11103 Interacts with miR-128/PPARGC1A to Regulate Milk Fat Metabolism in Dairy Cows

The quality of milk is inseparable from its milk components, and fatty acid content is a key factor affecting the quality of milk. In this study, the miRNA and mRNA profiles of the bovine mammary gland tissue during the dry period and the peak lactation period were determined through high-throughput sequencing. In total, 72 miRNA-mRNA regulatory pathways were screened, including miR-128/PPARGC1A regulatory pathways. miR-128 can directly target PPARGC1A and inhibit its expression. In addition, the study also observed that there was a miR-128 binding site in the sequence of the circular RNA circ11103, and circ11103 significantly reduced the expression of miR-128. circ11103 upregulated the triglyceride levels in bovine mammary epithelial cells (BMECs) and increased the contents of unsaturated fatty acids. However, miR-128 decreased triglyceride and cholesterol levels in BMECs. This study aims to analyze the mechanism governing the regulatory effect of circ11103 on milk fat metabolism, which provides new insights into improving milk quality.