PDF(Pubmed)
Abstract：
BACKGROUND: As cows transition from pregnancy to lactation, free fatty acids (FFA) are mobilized from adipose tissues (AT) through lipolysis to counter energy deficits. In clinically healthy cows, lipolysis intensity is reduced throughout lactation; however, if FFA release exceeds tissue demands or the liver\'s metabolic capacity, lipid byproducts accumulate, increasing cows\' risk of metabolic and infectious disease. Endocannabinoids (eCBs) and their congeners, N-acylethanolamines (NAEs), are lipid-based compounds that modulate metabolism and inflammation. Their synthesis and release depend upon the availability of FFA precursors and the abundance of synthesizing and degrading enzymes and transporters. Therefore, we hypothesized that eCB production and transcription of endocannabinoid system components are modulated by lipolysis pathways in adipocytes. To test this hypothesis, we stimulated canonical (isoproterenol, 1 µmol/L; ISO) and inflammatory (lipopolysaccharide, 1 µg/mL; LPS) lipolysis pathways in adipocytes isolated from the AT of 5 Holstein dairy cows. Following, we assessed lipolysis intensity, adipocytes\' release of eCBs, and transcription of endocannabinoid system components.
RESULTS: We found that ISO and LPS stimulated lipolysis at comparable intensities. Exposure to either treatment tended to elevate the release of eCBs and NAEs by cultured adipocytes; however, specific eCBs and NAEs and the transcriptional profiles differed by treatment. On one hand, ISO enhanced adipocytes\' release of 2-arachidonoylglycerol (2-AG) but reduced NAE production. Notably, ISO enhanced the cells\' expression of enzymes associated with 2-AG biosynthesis (INPP5F, GDPD5, GPAT4), transport (CD36), and adipogenesis (PPARG). Conversely, LPS enhanced adipocytes\' synthesis and release of N-arachidonoylethanolamide (AEA). This change coincided with enhanced transcription of the NAE-biosynthesizing enzyme, PTPN22, and adipocytes\' transcription of genes related to eCB degradation (PTGS2, MGLL, CYP27B1). Furthermore, LPS enhanced adipocytes\' transcription of eCB and NAE transporters (HSPA1A, SCP2) and the expression of the anti-adipogenic ion channel, TRPV3.
CONCLUSIONS: Our data provide evidence for distinct modulatory roles of canonical and inflammatory lipolysis pathways over eCB release and transcriptional regulation of biosynthesis, degradation, transport, and ECS signaling in cows\' adipocytes. Based on our findings, we conclude that, within adipocytes, eCB production and ECS component expression are, at least in part, mediated by lipolysis in a pathway-dependent manner. These findings contribute to a deeper understanding of the molecular mechanisms underlying metabolic regulation in dairy cows\' AT, with potential implications for prevention and treatment of inflammatory and metabolic disorders.
RESULTS: We found that ISO and LPS stimulated lipolysis at comparable intensities. Exposure to either treatment tended to elevate the release of eCBs and NAEs by cultured adipocytes; however, specific eCBs and NAEs and the transcriptional profiles differed by treatment. On one hand, ISO enhanced adipocytes\' release of 2-arachidonoylglycerol (2-AG) but reduced NAE production. Notably, ISO enhanced the cells\' expression of enzymes associated with 2-AG biosynthesis (INPP5F, GDPD5, GPAT4), transport (CD36), and adipogenesis (PPARG). Conversely, LPS enhanced adipocytes\' synthesis and release of N-arachidonoylethanolamide (AEA). This change coincided with enhanced transcription of the NAE-biosynthesizing enzyme, PTPN22, and adipocytes\' transcription of genes related to eCB degradation (PTGS2, MGLL, CYP27B1). Furthermore, LPS enhanced adipocytes\' transcription of eCB and NAE transporters (HSPA1A, SCP2) and the expression of the anti-adipogenic ion channel, TRPV3.
CONCLUSIONS: Our data provide evidence for distinct modulatory roles of canonical and inflammatory lipolysis pathways over eCB release and transcriptional regulation of biosynthesis, degradation, transport, and ECS signaling in cows\' adipocytes. Based on our findings, we conclude that, within adipocytes, eCB production and ECS component expression are, at least in part, mediated by lipolysis in a pathway-dependent manner. These findings contribute to a deeper understanding of the molecular mechanisms underlying metabolic regulation in dairy cows\' AT, with potential implications for prevention and treatment of inflammatory and metabolic disorders.
摘要：
背景：随着奶牛从怀孕过渡到哺乳期，游离脂肪酸(FFA)通过脂解从脂肪组织(AT)动员以对抗能量缺乏。在临床健康的奶牛中，在整个泌乳过程中，脂解强度降低；然而，如果FFA释放超过组织需求或肝脏的代谢能力，脂质副产物积累，增加奶牛代谢和传染病的风险。内源性大麻素（eCBs）及其同源物，N-酰基乙醇胺(NAE),是调节代谢和炎症的脂类化合物。它们的合成和释放取决于FFA前体的可用性以及合成和降解酶和转运蛋白的丰度。因此,我们假设eCB的产生和内源性大麻素系统组分的转录受脂肪细胞脂解途径的调节.为了检验这个假设，我们刺激了典型的(异丙肾上腺素，1µmol/L；ISO）和炎症（脂多糖，1µg/mL；LPS）从5头荷斯坦奶牛的AT分离的脂肪细胞中的脂解途径。Follows,我们评估了脂解强度，脂肪细胞释放eCBs，和内源性大麻素系统成分的转录。
结果:我们发现ISO和LPS以相当的强度刺激脂解。暴露于任何一种治疗都倾向于提高培养的脂肪细胞的eCB和NAE的释放；然而，特定的eCB和NAE以及转录谱因治疗而异。一方面,ISO增强脂肪细胞释放2-花生四酰基甘油(2-AG)但减少NAE产生。值得注意的是,ISO增强了与2-AG生物合成相关的酶的细胞表达(INPP5F，GDPD5，GPAT4），运输（CD36），和脂肪生成（PPARG）。相反，LPS增强脂肪细胞合成和N-花生四烯酸乙醇胺（AEA）的释放。这种变化与NAE生物合成酶的转录增强相吻合，PTPN22和脂肪细胞转录与eCB降解相关的基因(PTGS2，MGLL，CYP27B1)。此外，LPS增强脂肪细胞eCB和NAE转运蛋白的转录(HSPA1A，SCP2）和抗脂肪离子通道的表达，TRPV3.
结论：我们的数据为规范和炎症脂解途径对eCB释放和生物合成转录调节的不同调节作用提供了证据，降解，运输,和ECS信号在奶牛脂肪细胞中的作用。根据我们的发现,我们的结论是，在脂肪细胞内，eCB生产和ECS组件表达式是，至少在某种程度上,脂解以途径依赖性方式介导。这些发现有助于更深入地了解奶牛AT代谢调节的分子机制，对炎症和代谢紊乱的预防和治疗有潜在的影响。
结果:我们发现ISO和LPS以相当的强度刺激脂解。暴露于任何一种治疗都倾向于提高培养的脂肪细胞的eCB和NAE的释放；然而，特定的eCB和NAE以及转录谱因治疗而异。一方面,ISO增强脂肪细胞释放2-花生四酰基甘油(2-AG)但减少NAE产生。值得注意的是,ISO增强了与2-AG生物合成相关的酶的细胞表达(INPP5F，GDPD5，GPAT4），运输（CD36），和脂肪生成（PPARG）。相反，LPS增强脂肪细胞合成和N-花生四烯酸乙醇胺（AEA）的释放。这种变化与NAE生物合成酶的转录增强相吻合，PTPN22和脂肪细胞转录与eCB降解相关的基因(PTGS2，MGLL，CYP27B1)。此外，LPS增强脂肪细胞eCB和NAE转运蛋白的转录(HSPA1A，SCP2）和抗脂肪离子通道的表达，TRPV3.
结论：我们的数据为规范和炎症脂解途径对eCB释放和生物合成转录调节的不同调节作用提供了证据，降解，运输,和ECS信号在奶牛脂肪细胞中的作用。根据我们的发现,我们的结论是，在脂肪细胞内，eCB生产和ECS组件表达式是，至少在某种程度上,脂解以途径依赖性方式介导。这些发现有助于更深入地了解奶牛AT代谢调节的分子机制，对炎症和代谢紊乱的预防和治疗有潜在的影响。
