scholarly journals Study on the Regulation Mechanism of Lipopolysaccharide on Oxidative Stress and Lipid Metabolism of Bovine Mammary Epithelial Cells

2021 ◽  
pp. 777-785
Author(s):  
L LI ◽  
W TANG ◽  
M ZHAO ◽  
B GONG ◽  
M CAO ◽  
...  

The long-term feeding of a high-concentrate diet (the concentrate ratio is greater than 60 %) leads to mammary gland inflammatory response in ruminants and decreased quality in dairy cows and affects the robust development of the dairy industry. The main reason is closely related to elevated lipopolysaccharide (LPS) in the body. In this experiment, a bovine mammary epithelial cell line (MAC-T) was used as a model, and LPS at different concentrations (0 ng/ml, 1 ng/ml, 10 ng/ml, 100 ng/ml, 1000 ng/ml, 10000 ng/ml) was added to the cells. The cell survival rate, oxidative stress indicators, total lipid droplet area, triglyceride content and key genes regulating lipid metabolism were detected by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT), assay kit, microscope observation and RT-PCR methods to explore the regulatory mechanism of mammary health and milk fat synthesis. The results showed that compared with those of the control group, the survival rates of cells were significantly decreased after 9 h of stimulation with 1000 ng/ml and 10000 ng/ml LPS (P<0.01). The contents of superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (T-AOC) in cells were significantly decreased (P<0.05). Compared with that of the control group, the content of malondialdehyde (MDA) in cells was significantly increased (P<0.05) after stimulation with 10000 ng/ml LPS for 9 h. After 9 h of stimulation with 100 ng/ml, 1000 ng/ml and 10000 ng/ml LPS, the total lipid drop area and triglyceride (TG) content of MAC-T cells were significantly decreased (P<0.05). The expression levels of fatty acid synthesis-related genes Acetyl-CoA carboxylase (ACC) and Stearoyl-CoA desaturase 1 (SCD-1) were significantly decreased after 9 h of stimulation with 100 ng/ml, 1000 ng/ml and 10000 ng/ml LPS (P<0.05), while the expression levels of Fatty Acid synthetase (FAS) were significantly decreased after stimulation with 1000 ng/ml and 10000 ng/ml LPS (P<0.05). TG synthesis by the related gene Diacylglycerol acyltransferase-1 (DGAT1) was significantly lower than that of the control group after stimulation with 1000 ng/ml and 10000 ng/ml LPS for 9 h (P<0.05), and Diacylglycerol acyltransferase-2 (DGAT2) also showed a significant decrease after 10000 ng/ml LPS stimulation (P<0.05). In conclusion, adding different concentrations of LPS to MAC-T cells not only led to a decrease in cell activity, resulting in oxidative damage, but also affected fatty acid and TG synthesis, which may ultimately be closely related to the decrease in milk fat synthesis.

2020 ◽  
Vol 11 (10) ◽  
pp. 8625-8636
Author(s):  
Zhi Chen ◽  
Shuangfeng Chu ◽  
Yusheng Liang ◽  
Tianle Xu ◽  
Yujia Sun ◽  
...  

Both mRNA and miRNA play an important role in the regulation of mammary fatty acid metabolism and milk fat synthesis.


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.


Antioxidants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 55
Author(s):  
Nana Ma ◽  
Guozhen Wei ◽  
Hongzhu Zhang ◽  
Hongyu Dai ◽  
Animesh Chandra Roy ◽  
...  

Lipopolysaccharide (LPS) is the dominating endotoxin of Gram-negative bacteria, which can cause mastitis. Bovine mammary epithelial cells (BMECs), as major components of the mammary gland, usually suffer LPS challenge. Cis-9, trans-11 conjugated linoleic acid (CLA) has been reported to have anti-inflammatory characteristics, while its anti-oxidative ability to maintain cellular homeostasis in BMECs under LPS challenge is limited. Therefore, we studied whether cis-9, trans-11 CLA can restore the disturbance of cellular homeostasis indicated by the redox status and autophagy level caused by LPS and have an effect on cellular function- milk fat metabolism. For oxidative stress, LPS challenge promoted the formation of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS) and decreased the concentration of glutathione. Anti-oxidative signaling regulated by transcription factor nuclear factor, erythroid 2 like 2 (Nrf2) was also depressed by LPS at the mRNA and protein level. However, cis-9, trans-11 CLA pretreatment downregulated the formation of ROS and TBARS and upregulated the expression of antioxidative enzymes. As a part of innate immunity, autophagy was also motivated by LPS challenge, while CLA decreased the autophagy level. LPS and H2O2 inhibited milk fat synthesis-related transcription factor sterol regulatory element binding protein (SREBP1), peroxisome proliferator activated receptor gamma (PPARG) and their downstream enzymes. Furthermore, 50 uM cis-9, trans-11 CLA promoted the mRNA and protein abundance of milk fat synthesis-related genes and lipid droplet formation in BMECs. In conclusion, LPS challenge disturbed the cellular homeostasis and depressed milk fat synthesis in BMECs; while cis-9, trans-11 CLA alleviated oxidative stress and decreased autophagy level, thus promoting milk fat synthesis, which offers a natural therapeutic strategy for mastitis.


2021 ◽  
Vol 8 ◽  
Author(s):  
Ping Jiang ◽  
Ambreen Iqbal ◽  
Mengyan Wang ◽  
Xiaohui Li ◽  
Xibi Fang ◽  
...  

The acyl-CoA dehydrogenase family of enzymes includes short/branched-chain acyl-CoA dehydrogenase (ACADSB), which catalyzes the dehydrogenation of acyl-CoA derivatives in fatty acid metabolism. Our previous findings suggested that ACADSB was a critical candidate gene affecting milk fat synthesis by comparing the transcriptome in bovine mammary epithelial cells (bMECs) from Chinese Holstein dairy cows producing high-fat and low-fat milk as well as gene functional validation studies on the cellular level. In the present study, ACADSB in bMECs was knocked out (KO) using a CRISPR/Cas9 system, and mRNA transcriptome was further sequenced to verify the function of the ACADSB gene and analyze its correlation with lipid metabolism. The findings revealed that 15,693 genes were expressed, 1,548 genes were differentially expressed genes (DEGs), and 6,098 GO terms were enriched, of which 637 GO terms were greatly enhanced, such as phospholipid-translocation ATPase activity (GO:0004012), lipoprotein lipase activity (GO:0004465), acyl-CoA desaturase activity (GO:0016215), and so on. The analysis by KEGG showed that DEGs were distributed over 247 pathogens, of which 49 were significantly enriched, including the metabolism of fatty acids (PATH: 01212), metabolism of glycerolipid (PATH: 00561), and signaling of adipocytokines (PATH: 04920). The CHOL, TGs and FFA contents in bMECs were reduced when the ACADSB gene was knocked out. The RT2 Profiler PCR array also revealed that the loss of the ACADSB gene changed the expression levels of functional genes involved in lipid metabolism, including ACADL, ACOX2, ACAT2, and FABP3. In conclusion, the current findings show that ACADSB is a key regulator of lipid metabolism in bMECs. The ACADSB−/− bMECs could also be useful genetic material and tools for future research into gene functions related to lipid and fatty acid metabolism. It will be valuable for revealing the gene regulatory roles and molecular mechanisms in milk fat synthesis.


PPAR Research ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Hengbo Shi ◽  
Wangsheng Zhao ◽  
Changhui Zhang ◽  
Khuram Shahzad ◽  
Jun Luo ◽  
...  

To explore the large-scale effect of peroxisome proliferator-activated receptorγ(PPARG) in goat mammary epithelial cells (GMEC), an oligonucleotide microarray platform was used for transcriptome profiling in cells overexpressingPPARGand incubated with or without rosiglitazone (ROSI, a PPARγagonist). A total of 1143 differentially expressed genes (DEG) due to treatment were detected. The Dynamic Impact Approach (DIA) analysis uncovered the most impacted and induced pathways “fatty acid elongation in mitochondria,” “glycosaminoglycan biosynthesis-keratan sulfate,” and “pentose phosphate pathway.” The data highlights the central role ofPPARGin milk fatty acid metabolism via controlling fatty acid elongation, biosynthesis of unsaturated fatty acid, lipid formation, and lipid secretion; furthermore, its role related to carbohydrate metabolism promotes the production of intermediates required for milk fat synthesis. Analysis of upstream regulators indicated thatPPARGparticipates in multiple physiological processes via controlling or cross talking with other key transcription factors such asPPARDandNR1H3(also known as liver-X-receptor-α). This transcriptome-wide analysis represents the first attempt to better understand the biological relevance of PPARG expression in ruminant mammary cells. Overall, the data underscored the importance of PPARG in mammary lipid metabolism and transcription factor control.


2021 ◽  
pp. 1-8
Author(s):  
Maroula Lambidou ◽  
Birgit Alteheld ◽  
Rolf Fimmers ◽  
Frank Jochum ◽  
Antonia Nomayo ◽  
...  

<b><i>Introduction:</i></b> Recently, new commercial infant formulas have been composed considering novel fat blends and oligosaccharides to better resemble the fatty acid (FA) composition and stereospecific distribution (e.g., increased amount of ß-palmitate) as well as probiotics content of human breast milk. We hypothesized that these newly composed infant formulas may decrease fecal FA soap excretion and may positively affect erythrocyte FA profiles compared with regular formulas. <b><i>Methods:</i></b> Healthy infants were randomly assigned to receive a high-sn-2-palmitate formula (&#x3e;25% of the PA is esterified to the sn-2 position of the glycerol backbone, verum: <i>n</i> = 30) or a “standard” formula containing &#x3c;10% of PA in sn-2 position and no oligosaccharides (control: <i>n</i> = 27); a non-randomized group of breast-fed infants served as control. Anthropometric data of the infants (body weight, recumbent length, and head circumference) were recorded at inclusion (visit 1) and 6 and 12 weeks after onset of intervention (visits 2 and 3). Blood samples for erythrocyte FA analysis (gas chromatography) were taken at visits 1 and 2; stool samples were collected at visit 2. <b><i>Results:</i></b> Quantitative formula intake (mL/kg body weight × day) at visit 2 (verum: 155 ± 30, control: 164 ± 30) and visit 3 (verum: 134 ± 26, control: 134 ± 21) was comparable. Six weeks after onset of intervention, stool total FA soaps, palmitate soaps, and total FAs were similar in both formula-fed groups but significantly higher than in breast-fed infants. During the 6-week intervention, erythrocyte palmitate decreased significantly from baseline in all 3 groups with no group differences (verum: 29.20 ± 1.17 to 27.12 ± 0.66, control: 29.88 ± 2.00 to 27.01 ± 0.94, breast-fed: 30.20 ± 0.86 to 26.84 ± 0.98). For selected FAs, significant changes over time in verum and control group were obvious but without formula effects. Some variations in the FA profile of breast-fed infants compared to both verum and control groups were observed. <b><i>Conclusions:</i></b> In contrast to our hypothesis, feeding a newly composed infant formula based on a fat blend with 25% of PA in the sn-2 position of triacylglycerols and supplemented with a prebiotic could not decrease insoluble FA soap excretion compared with a standard product; in this respect, breastfeeding is obviously the best choice. Surprisingly, erythrocyte FA profiles were comparable in formula-fed and breast-fed infants; obvious alterations in FA composition of the respective fat sources and structure did not affect FA incorporation into membranes. Caution should be, however, exercised in drawing robust conclusions in the absence of larger, adequately powered intervention studies.


2020 ◽  
pp. 1-7
Author(s):  
Jianfa Wang ◽  
Shuai Lian ◽  
Jun Song ◽  
Hai Wang ◽  
Xu Zhang ◽  
...  

Abstract Lipopolysaccharides (LPS) could induce milk fat depression via regulating the body and blood fat metabolism. However, it is not completely clear how LPS might regulate triglyceride synthesis in dairy cow mammary epithelial cells (DCMECs). DCMECs were isolated and purified from dairy cow mammary tissue and treated with LPS. The level of triglyceride synthesis, the expression and activity of the liver X receptor α (LXRα), enzymes related to de novo fatty acid synthesis, and the expression of the fatty acid transporters were investigated. We found that LPS decreased the level of triglyceride synthesis via a down-regulation of the transcription, translation, and nuclear translocation level of the LXRα. The results also indicated that the transcription level of the LXRα target genes, sterol regulatory element binding protein 1 (SREBP1), fatty acid synthetase (FAS), acetyl-CoA carboxylase-1 (ACC1), were significantly down-regulated in DCMECs after LPS treatment. Our data may provide new insight into the mechanisms of milk fat depression caused by LPS.


2015 ◽  
Vol 101 (4) ◽  
pp. 870-878 ◽  
Author(s):  
Mette Bohl ◽  
Ann Bjørnshave ◽  
Kia V Rasmussen ◽  
Anne Grethe Schioldan ◽  
Bashar Amer ◽  
...  

ABSTRACT Background: Abdominal obesity and exaggerated postprandial lipemia are independent risk factors for cardiovascular disease (CVD) and mortality, and both are affected by dietary behavior. Objective: We investigated whether dietary supplementation with whey protein and medium-chain saturated fatty acids (MC-SFAs) improved postprandial lipid metabolism in humans with abdominal obesity. Design: We conducted a 12-wk, randomized, double-blinded, diet intervention study. Sixty-three adults were randomly allocated to one of 4 diets in a 2 × 2 factorial design. Participants consumed 60 g milk protein (whey or casein) and 63 g milk fat (with high or low MC-SFA content) daily. Before and after the intervention, a high-fat meal test was performed. We measured changes from baseline in fasting and postprandial triacylglycerol, apolipoprotein B-48 (apoB-48; reflecting chylomicrons of intestinal origin), free fatty acids (FFAs), insulin, glucose, glucagon, glucagon-like peptide 1 (GLP-1), and gastric inhibitory polypeptide (GIP). Furthermore, changes in the expression of adipose tissue genes involved in lipid metabolism were investigated. Two-factor ANOVA was used to examine the difference between protein types and fatty acid compositions, as well as any interaction between the two. Results: Fifty-two participants completed the study. We found that the postprandial apoB-48 response decreased significantly after whey compared with casein (P = 0.025) independently of fatty acid composition. Furthermore, supplementation with casein resulted in a significant increase in the postprandial GLP-1 response compared with whey (P = 0.003). We found no difference in postprandial triacylglycerol, FFA, insulin, glucose, glucagon, or GIP related to protein type or MC-SFA content. We observed no interaction between milk protein and milk fat on postprandial lipemia. Conclusion: We found that a whey protein supplement decreased the postprandial chylomicron response compared with casein in persons with abdominal obesity, thereby indicating a beneficial impact on CVD risk. This trial was registered at clinicaltrials.gov as NCT01472666.


2021 ◽  
Author(s):  
Zhiyun Hao ◽  
Yuzhu Luo ◽  
Jiqing Wang ◽  
Jon Hickford ◽  
Huitong Zhou ◽  
...  

In our previous studies, microRNA-432 (miR-432) was found to be one of differentially expressed miRNAs in ovine mammary gland between the two breeds of lactating sheep with different milk production...


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