A novel mutation in the promoter region of RPL8 regulates milk fat traits in dairy cattle by binding transcription factor Pax6

BDH1 identified by transcriptome has a negative effect on lipid metabolism in mammary epithelial cells of dairy goats

BACKGROUND

The 3-hydroxybutyrate dehydrogenase 1 (BDH1) mainly participates in the regulation of milk fat synthesis and ketone body synthesis in mammary epithelial cells. In our previous study, BDH1 was identified as a key candidate gene regulating lipid metabolism in mammary glands of dairy goats by RNA-seq. This study aimed to investigate the effect of BDH1 on lipid metabolism in mammary epithelial cells of dairy goats (GMECs).

RESULTS

The results suggest that BDH1 plays a significant role in reducing triacylglycerol content and lipid droplet accumulation in GMECs (p < 0.05). Overexpression of BDH1 significantly decreased the expression of lipid metabolism-related genes (SREBF1 and GPAM) and reduced the levels of C14:0 and C17:1, while increasing FABP3 expression and C10:0 concentration (p < 0.05). Interference with BDH1 significantly increased the expression of SREBF1 and GPAM and the concentration of C14:0, C15:1, and C20:1, but significantly decreased FABP3 and C18:0 (p < 0.05). Treatment of GMECs with β-hydroxybutyric acid (R-BHBA) significantly decreased the expression of FASN, ACACA, LPL, SREBF1, FABP3, ACSL1, GPAM, DGAT1, and triacylglycerol content, while significantly increasing the expression of BDH1 (p < 0.05). Interference with BDH1 rescued the reduction of cellular TAG content and the expression of FASN, LPL, SREBF1, ACSL1, and GPAM in BHBA-treated GMECs.

CONCLUSION

In conclusion, BDH1 negatively regulates lipid metabolism in mammary glands of dairy goats. Furthermore, it may mitigate the inhibitory effect of R-BHBA on lipid metabolism in GMECs.

Genome-Wide Identification and Evolutionary and Mutational Analysis of the Bos taurus Pax Gene Family

Bos taurus is known for its tolerance of coarse grains, adaptability, high temperature, humidity, and disease resistance. Primarily, cattle are raised for their meat and milk, and pinpointing genes associated with traits relevant to meat production can enhance their overall productivity. The aim of this study was to identify the genome, analyze the evolution, and explore the function of the Pax gene family in B. taurus to provide a new molecular target for breeding in meat-quality-trait cattle. In this study, 44 Pax genes were identified from the genome database of five species using bioinformatics technology, indicating that the genetic relationships of bovids were similar. The Pax3 and Pax7 protein sequences of the five animals were highly consistent. In general, the Pax gene of the buffalo corresponds to the domestic cattle. In summary, there are differences in affinity between the Pax family genes of buffalo and domestic cattle in the Pax1/9, Pax2/5/8, Pax3/7, and Pax4/6 subfamilies. We believe that Pax1/9 has an effect on the growth traits of buffalo and domestic cattle. The Pax3/7 gene is conserved in the evolution of buffalo and domestic animals and may be a key gene regulating the growth of B. taurus. The Pax2/5/8 subfamily affects coat color, reproductive performance, and milk production performance in cattle. The Pax4/6 subfamily had an effect on the milk fat percentage of B. taurus. The results provide a theoretical basis for understanding the evolutionary, structural, and functional characteristics of the Pax family members of B. taurus and for molecular genetics and the breeding of meat-production B. taurus species.

Genetics, environmental stress, and amino acid supplementation affect lactational performance via mTOR signaling pathway in bovine mammary epithelial cells

Mammary glands are known for their ability to convert nutrients present in the blood into milk contents. In cows, milk synthesis and the proliferation of cow mammary epithelial cells (CMECs) are regulated by various factors, including nutrients such as amino acids and glucose, hormones, and environmental stress. Amino acids, in particular, play a crucial role in regulating cell proliferation and casein synthesis in mammalian epithelial cells, apart from being building blocks for protein synthesis. Studies have shown that environmental factors, particularly heat stress, can negatively impact milk production performance in dairy cattle. The mammalian target of rapamycin complex 1 (mTORC1) pathway is considered the primary signaling pathway involved in regulating cell proliferation and milk protein and fat synthesis in cow mammary epithelial cells in response to amino acids and heat stress. Given the significant role played by the mTORC signaling pathway in milk synthesis and cell proliferation, this article briefly discusses the main regulatory genes, the impact of amino acids and heat stress on milk production performance, and the regulation of mTORC signaling pathway in cow mammary epithelial cells.

Two single nucleotide variants in the miR-23a promoter affect granulosa cell apoptosis

microRNAs (miRNAs) are well known to be important in mammalian female fertility. However, the genetic regulation of miRNAs associated with female fertility remains largely unknown. Here, we report that two single-nucleotide variants (SNVs) in the miR-23a promoter strongly influence miR-23a transcription and function in granulosa cell (GC) apoptosis. Two novel SNVs, g.-283G>C and g.-271C>T, were detected in the porcine miR-23a promoter by pooled-DNA sequencing. Furthermore, SNVs in the promoter region influenced miR-23a transcription in porcine GCs by altering its promoter activity. Functionally, SNVs in the promoter strongly influenced miR-23a regulation of early apoptosis in porcine GCs cultured in vitro. In addition, a preliminary association analysis showed that the combined genotypes of the two SNVs, rather than a single SNV, were tentatively associated with sow fertility traits in a Large White population. Overall, our findings suggest that the SNVs g.-283G>C and g.-271C>T in the miR-23a promoter are causal variants affecting GC apoptosis and miR-23a may be a potential small-molecule nonhormonal drug for regulating female fertility.

Regulation of Key Genes for Milk Fat Synthesis in Ruminants

Milk fat is the most important and energy-rich substance in milk and plays an important role in the metabolism of nutrients during human growth and development. It is mainly used in the production of butter and yogurt. Milk fat not only affects the flavor and nutritional value of milk, but also is the main target trait of ruminant breeding. There are many key genes involve in ruminant milk fat synthesis, including ACSS2, FASN, ACACA, CD36, ACSL, SLC27A, FABP3, SCD, GPAM, AGPAT, LPIN, DGAT1, PLIN2, XDH, and BTN1A1. Taking the de novo synthesis of fatty acids (FA) and intaking of long-chain fatty acids (LCFA) in blood to the end of lipid droplet secretion as the mainline, this manuscript elucidates the complex regulation model of key genes in mammary epithelial cells (MECs) in ruminant milk fat synthesis, and constructs the whole regulatory network of milk fat synthesis, to provide valuable theoretical basis and research ideas for the study of milk fat regulation mechanism of ruminants.

Genetic and Physiological Factors Affecting Human Milk Production and Composition

Human milk is considered the optimal nutrition for infants as it provides additional attributes other than nutritional support for the infant and contributes to the mother's health as well. Although breastfeeding is the most natural modality to feed infants, nowadays, many mothers complain about breastfeeding difficulties. In addition to environmental factors that may influence lactation outcomes including maternal nutrition status, partner's support, stress, and latching ability of the infant, intrinsic factors such as maternal genetics may also affect the quantitative production and qualitative content of human milk. These genetic factors, which may largely affect the infant's growth and development, as well as the mother's breastfeeding experience, are the subject of the present review. We specifically describe genetic variations that were shown to affect quantitative human milk supply and/or its qualitative content. We further discuss possible implications and methods for diagnosis as well as treatment modalities. Although cases of nutrient-deficient human milk are considered rare, in some ethnic groups, genetic variations that affect human milk content are more abundant, and they should receive greater attention for diagnosis and treatment when necessary. From a future perspective, early genetic diagnosis should be directed to target and treat breastfeeding difficulties in real time.