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 reduc...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 F FA release exceeds tissue demands or the liver's metabolic capacity,lipid byproducts accumulate,incre a sing 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 hypothesise we stimulated canonical(isoproterenol,1μmol/L;ISO)and inflammatory(lipopolysaccharide,1μg/m L;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.Klotably,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.展开更多
基金funded by the Michigan Animal Agricultural Alliance competitive project#AA-23–0014United States Department of Agriculture National Institute of Food and Agriculture(USDA)projects#2019–67015-29443 and#2021–67037-34657+2 种基金the United States-Israel Binational Agricultural Research Development(BARD)Fund project#IS-5167–19the Office for the Associate Dean of Research at Michigan State Universitysupported by USDA National Institute of Food and Agriculture’s Agriculture and Food Research Initiative Educational Workforce and Development Program award#2024-67011-42947。
文摘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 F FA release exceeds tissue demands or the liver's metabolic capacity,lipid byproducts accumulate,incre a sing 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 hypothesise we stimulated canonical(isoproterenol,1μmol/L;ISO)and inflammatory(lipopolysaccharide,1μg/m L;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.Klotably,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.
