Characterisation of gene expression related to milk fat synthesis in the mammary tissue of lactating yaks

2017 ◽  
Vol 84 (3) ◽  
pp. 283-288 ◽  
Author(s):  
Jung Nam Lee ◽  
Yong Wang ◽  
Ya Ou Xu ◽  
Yu Can Li ◽  
Fang Tian ◽  
...  

This research communication describes the profile of gene expression related to the synthesis of yak milk as determined via quantitative reverse transcription polymerase chain reaction (RT-qPCR). Significant up-regulation during lactation were observed in genes related to fatty acid (FA) uptake from blood (LPL, CD36), intracellular FA transport (FABP3), intracellular FA activation of long- and short-chain FAs (ACSS1, ACSS2, ACSL1), de novo synthesis (ACACA), desaturation (SCD), triacyglycerol (TAG) synthesis (AGPAT6, GPAM, LPIN1), lipid droplet formation (PLIN2, BTN1A1, XDH), ketone body utilisation (BDH1, OXCT1), and transcription regulation (THRSP, PPARGC1A). In particular, intracellular de novo FA synthesis (ACSS2, ACACA, and FABP3) and TAG synthesis (GPAM, AGPAT6, and LPIN1), whose regulation might be orchestrated as part of the gene network under the control of SERBF1 in the milk fat synthesis process, were more activated compared to levels in dairy cows. However, the genes involved in lipid droplet formation (PLIN2, XDH, and BTN1A1) were expressed at lower levels compared to those in dairy cows, where these genes are mainly controlled by the PPARG regulator.

2020 ◽  
Author(s):  
Yu Cao ◽  
Juxiong Liu ◽  
Qing Zhang ◽  
Lijun Ma ◽  
Jiaxin Wang ◽  
...  

Abstract Background Kp-10 is a peptide hormone mainly involved in the initiation tissue development in puberty. Recent studies have shown that Kp-10 is involved in fat synthesis. However, the role of Kp-10 in milk fat synthesis in lactating dairy cows has not been reported. Therefore, this study investigated the correlation between GPR54 and milk fat synthesis in dairy cows and to study the underlying mechanism in BMECs. Results The results showed that the expression of GPR54, SREBP1 and FASN in mammary glands of high-milk fat dairy cows were significantly higher than those in mammary glands of low-milk fat dairy cows. Meanwhile, 10nM Kp-10 can significantly inhibit AMPK/SIRT6 signaling pathway and promote milk fat synthesis in BMECs through its receptor GPR54. Overexpression of SIRT6 significantly reduced the acetylation level of SREBP1 and milk fat synthesis in BMECs.Conclusions These results suggested that Kp-10 inhibits the AMPK / SIRT6 signaling pathway by mediating GPR54, thereby increasing SREBP1 acetylation levels and increasing milk fat synthesis in BMECs.


2019 ◽  
Vol 97 (9) ◽  
pp. 3823-3831 ◽  
Author(s):  
Yujuan Wang ◽  
Wenli Guo ◽  
Keqiong Tang ◽  
Yaning Wang ◽  
Linsen Zan ◽  
...  

Abstract Milk fat is a main nutritional component of milk, and it has become one of the important traits of dairy cow breeding. Recently, there is increasing evidence that microRNAs (miRNA) play significant roles in the process of milk fat synthesis in the mammary gland. Primary bovine mammary epithelial cells (BMEC) were harvested from midlactation cows and cultured in DMEM/F-12 medium with 10% fetal bovine serum, 100 units/mL penicillin, 100 µg/mL streptomycin, 5 µg/mL bovine insulin, 1 µg/mL hydrocortisone, and 2 µg/mL bovine prolactin. We found that miR-34b mimic transfection in BMEC reduced the content of intracellular triacylglycerol (TAG) and lipid droplet accumulation via triacylglycerol assay and Oil Red O staining; meanwhile, overexpression of miR-34b inhibited mRNA expression of lipid metabolism-related genes such as peroxisome proliferator-activated receptor gamma (PPARγ), fatty acid synthase (FASN), fatty acid binding protein 4 (FABP4), and CCAAT enhancer binding protein alpha (C/EBPα). Whereas miR-34b inhibitor resulted in completely opposite results. Furthermore, q-PCR and western blot analysis revealed the mRNA and protein expression levels of DCP1A were downregulated in miR-34b mimic transfection group and upregulated in miR-34b inhibitor group. Moreover, luciferase reporter assays verified that DCP1A was the direct target of miR-34b and DCP1A gene silencing in BMEC-inhibited TAG accumulation and suppressed lipid droplet formation. In conclusion, these findings revealed a novel miR-34b–DCP1A axis that has a significant role in regulating milk fat synthesis and suggested that miR-34b may be used to improve the beneficial ingredients in milk.


2021 ◽  
Author(s):  
Tong Mu ◽  
Honghong Hu ◽  
Xiaofang Feng ◽  
Yanfen Ma ◽  
Ying Wang ◽  
...  

Abstract Background: Long noncoding RNAs (lncRNAs) play an important regulatory role in various biological processes as a key regulatory factor. However, there are largely unknown for the function and expression profile of lncRNAs in milk fat synthesis of dairy cows. Results: In this study, RNA sequencing (RNA-seq) was used to research the whole genome expression of lncRNAs and mRNA transcripts in bovine mammary epithelial cells (BMECs) of dairy cows with high and low milk fat percentage (MFP), and joint analysis was carried out. We identified a total of 47 differentially expressed genes (DEGs) and 38 differentially expressed lncRNAs (DELs, Padj < 0.05), 11 candidate DEGs that may regulate milk fat metabolism were screened by enrichment analysis. Downregulated differential gene ENPP2 and upregulated differential gene BCAT1 are more likely to participate in the milk fat metabolism, and its function needs further experiments verification. The enrichment analysis of target genes predicted by DELs identified 7 cis (co-localization) and 10 trans (co-expression) candidate target genes related to milk lipid metabolism, corresponding to a total of 18 DELs. Among them, the targeting relationship between long intervening/intergenic noncoding RNA (lincRNA) TCONS_00082721 and FABP4 gene that predicts milk fat metabolism by co-localization and co-expression is worthy of attention. Based on the expression information of DELs, differential microRNAs (miRNAs), and lipid metabolism-related target genes, 156 competing endogenous RNAs (ceRNAs) interaction regulation networks related to milk fat metabolism were constructed. The regulatory network centered on miR-145 will be the focus of subsequent experimental research. The ceRNAs regulatory network related to TCONS_00082721 and TCONS_00172817 are more likely to be involved in milk fat synthesis. Conclusions: These results will provide new ways to understand the complex biology of dairy cow milk fat synthesis and provide valuable information for the breed improvement of Chinese Holstein cattle.


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