AIM To examine the role that enzyme Acyl-CoA:diacylglycerol acyltransferase-1(DGAT1) plays in postprandial gut peptide secretion and signaling.METHODS The standard experimental paradigm utilized to evaluate the incret...AIM To examine the role that enzyme Acyl-CoA:diacylglycerol acyltransferase-1(DGAT1) plays in postprandial gut peptide secretion and signaling.METHODS The standard experimental paradigm utilized to evaluate the incretin response was a lipid challenge.Following a lipid challenge,plasma was collected via cardiac puncture at each time point from a cohort of 5-8 mice per group from baseline at time zero to 10 h.Incretin hormones [glucagon like peptide-1(GLP-1),peptide tyrosine-tyrosine(PYY) and glucose dependent insulinotropic polypeptide(GIP)] were then quantitated.The impact of pharmacological inhibition of DGAT1 on the incretin effect was evaluated in WT mice.Additionally,a comparison of loss of DGAT1 function either by genetic ablation or pharmacological inhibition.To further elucidate the pathways and mechanisms involved in the incretin response to DGAT1 inhibition,other interventions [inhibitors of dipeptidyl peptidase-IV(sitagliptin),pancreatic lipase(Orlistat),GPR119 knockout mice] were evaluated.RESULTS DGAT1 deficient mice and wildtype C57/BL6J mice werelipid challenged and levels of both active and total GLP-1 in the plasma were increased.This response was further augmented with DGAT1 inhibitor PF-04620110 treated wildtype mice.Furthermore,PF-04620110 was able to dose responsively increase GLP-1 and PYY,but blunt GIP at all doses of PF-04620110 during lipid challenge.Combination treatment of PF-04620110 and Sitagliptin in wildtype mice during a lipid challenge synergistically enhanced postprandial levels of active GLP-1.In contrast,in a combination study with Orlistat,the ability of PF-04620110 to elicit an enhanced incretin response was abrogated.To further explore this observation,GPR119 knockout mice were evaluated.In response to a lipid challenge,GPR119 knockout mice exhibited no increase in active or total GLP-1 and PYY.However,PF-04620110 was able to increase total GLP-1 and PYY in GPR119 knockout mice as compared to vehicle treated wildtype mice.CONCLUSION Collectively,these data provide some insight into the mechanism by which inhibition of DGAT1 enhances intestinal hormone release.展开更多
Triacylglycerols(triglycerides,TAGs)are the major carbon and energy storage forms in various organisms,and important components of cellular membranes and signaling molecules;they have essential functions in multiple p...Triacylglycerols(triglycerides,TAGs)are the major carbon and energy storage forms in various organisms,and important components of cellular membranes and signaling molecules;they have essential functions in multiple physiological processes and stress regulation.Acyl-CoA:diacylglycerol acyltransferase(DGAT)catalyzes the final and only committed acylation step in the synthesis of TAGs in eukaryotes.The present work identified and isolated a novel gene,UpDGAT1,from the green tide alga Ulva prolifera.The activity of UpDGAT1 was confirmed by heterologous expression in a Saccharomyces cerevisiae TAG-deficient quadruple mutant.Results of thin-layer chromatography and BODIPY staining indicated that UpDGAT1 was able to restore TAG synthesis and lipid body formation in the yeast.Lipid analysis of yeast cells revealed that UpDGAT1 showed broad substrate specificity,accepting saturated as well as mono-and polyunsaturated acyl-CoAs as substrates.High salinity and high temperature stresses increased UpDGAT1 expression and TAG accumulation in U.prolifera.The present study provides clues to the functions of UpDGAT1 in TAG accumulation in,and stress adaptation of,U.prolifera.展开更多
Cultivated peanut is one of the primary sources of vegetable oil and protein in developing countries. DG〉A73 family in peanut cotyledons has no membrane-bound regions suggesting that cytosol is one of the sites fo...Cultivated peanut is one of the primary sources of vegetable oil and protein in developing countries. DG〉A73 family in peanut cotyledons has no membrane-bound regions suggesting that cytosol is one of the sites for triacylglycerol （TAG） biosynthesis in oilseeds. According to functional annotation and classification of 5 cDNA libraries, 12 unigenes were found with relation of peanut DGAT3 in different organs. Three clones of unigenes, OCP- contig168t OCPcontig12101-3 and OCPcontigl2388-1 were selected for sequencing. Full length sequence of DGAT3 was obtained, showing over 98% sequence similarity with peanut DGAT3 gene AY875644 or EU183333. Upon cluster analysis, DGAT3 of 40 culti- vars were divided into 3 types, namely AhDGATS-1, AhDGAT3-2 and AhDGAT3-3. Coding regions are 1023, 1038 and 1026 base pairs which encoded proteins with 340-, 345- and 341-amino acids, respectively. DGAT3-3 might be a novel gene type among the DGAT3 family which provides great help for studying DGAT3 gene evolution in peanut.展开更多
Microalgal oils, depending on their degree of unsaturation, can be utilized as either nutritional supplements or fuels; thus, a feedstock with genetically designed and tunable degree of unsaturation is desirable to ma...Microalgal oils, depending on their degree of unsaturation, can be utilized as either nutritional supplements or fuels; thus, a feedstock with genetically designed and tunable degree of unsaturation is desirable to maximize process efficiency and product versatility. Systematic profiling of ex vivo （in yeast）, in vitro, and in vivo activities of type-2 diacylglycerol acyltransferases in Nannochloropsis oceanica （NoDGAT2s or NoDGTTs）, via reverse genetics, revealed that NoDGAT2A prefers saturated fatty acids （SFAs）, NoDGAT2D prefers monounsaturated fatty acids （MUFAs）, and NoDGAT2C exhibits the strongest activity toward polyunsaturated fatty acids （PUFAs）. As NoDGAT2A, 2C, and 2D originated from the green alga, red alga, and eukaryotic host ancestral participants of secondary endosymbiosis, respectively, a mecha- nistic model of oleaginousness was unveiled, in which the indigenous and adopted NoDGAT2s formulated functional complementarity and specific transcript abundance ratio that underlie a rigid SFA：MUFA：PUFA hierarchy in triacylglycerol （TAG）. By rationally modulating the ratio of NoDGAT2A＇：2C^D transcripts, a bank of N. oceanica strains optimized for nutritional supplement or fuel production with a wide range of degree of unsaturation were created, in which proportion of SFAs, MUFAs, and PUFAs in TAG varied by 1.3-, 3.7-, and 11.2-fold, respectively. This established a novel strategy to simultaneously improve productivity and quality of oils from industrial microalgae.展开更多
Objective To identify the active compounds from the barks of Betula platyphylla for inhibitory on diacylglycerol acyltransferase（DGAT1）.Methods Bioassay-guided fractionation resulted in the isolation of DGAT1 inhibi...Objective To identify the active compounds from the barks of Betula platyphylla for inhibitory on diacylglycerol acyltransferase（DGAT1）.Methods Bioassay-guided fractionation resulted in the isolation of DGAT1 inhibitory activity of lupane triterpenes.Results Ten compounds were identified as lupenone（1）,lupeol（2）,betulinic acid（3）,betulinaldehyde（4）,betulin（5）,3-deoxybetulonic acid（6）,glochidonol（7）,lup-20/29-ene-1β/3β-diol（8）,3α-hydroxy-lup-20（29）-en-23,28-dioic acid（9）,and 3α,11α-dihydroxy-23-oxo-lup-20（29）-en-28-oic acid（10）.Compounds 3-6,9,and 10 inhibited DGAT1 with IC50 values ranging from（11.2±0.3）to（38.6±1.2）μmol/L.Conclusion Compounds 6,9,and 10 are first isolated from the barks of B.platyphylla.,and compounds 3-6,9,and 10 from the barks of B.platyphylla are responsible for the inhibition on DGAT1.展开更多
Two cDNAs encoding putative type 1 acyl-CoA： diacylglycerol acyltransferases （DGAT1, EC 2.3.1.20）, were cloned from Tetraena mongolica Maxim., an extreme xerophyte with high oil content in the stems. The 1,488-bp a...Two cDNAs encoding putative type 1 acyl-CoA： diacylglycerol acyltransferases （DGAT1, EC 2.3.1.20）, were cloned from Tetraena mongolica Maxim., an extreme xerophyte with high oil content in the stems. The 1,488-bp and 1,485-bp of the open reading frame （ORF） of the two cDNAs, designated as TmDGAT1a and TmDGAT1b, were both predicted to encode proteins of 495 and 494 amino acids, respectively. Southern blot analysis revealed that TmDGAT1a and TmDGAT1b both had low copy numbers in the T. mongolica genome. In addition to ubiquitous expression with different intensity in different tissues, including stems, leaves and roots, TmDGAT1a and TmDGAT1b, were found to be strongly induced by high salinity, drought and osmotic stress, resulting in a remarkable increase of triacylglycerol （TAG） accumulation in T. mongolica plantlets. TmDGAT1a and TmDGAT1b activities were confirmed in the yeast H1246 quadruple mutant （DGA1, LRO1, ARE1, ARE2） by restoring DGAT activity of the mutant host to produce TAG. Overexpression of TmDGAT1a and TmDGAT1b in soybean hairy roots as well as in T. mongolica calli both resulted in an increase in oil content （ranging from 37% to 108%）, accompanied by altered fatty acid profiles.展开更多
文摘AIM To examine the role that enzyme Acyl-CoA:diacylglycerol acyltransferase-1(DGAT1) plays in postprandial gut peptide secretion and signaling.METHODS The standard experimental paradigm utilized to evaluate the incretin response was a lipid challenge.Following a lipid challenge,plasma was collected via cardiac puncture at each time point from a cohort of 5-8 mice per group from baseline at time zero to 10 h.Incretin hormones [glucagon like peptide-1(GLP-1),peptide tyrosine-tyrosine(PYY) and glucose dependent insulinotropic polypeptide(GIP)] were then quantitated.The impact of pharmacological inhibition of DGAT1 on the incretin effect was evaluated in WT mice.Additionally,a comparison of loss of DGAT1 function either by genetic ablation or pharmacological inhibition.To further elucidate the pathways and mechanisms involved in the incretin response to DGAT1 inhibition,other interventions [inhibitors of dipeptidyl peptidase-IV(sitagliptin),pancreatic lipase(Orlistat),GPR119 knockout mice] were evaluated.RESULTS DGAT1 deficient mice and wildtype C57/BL6J mice werelipid challenged and levels of both active and total GLP-1 in the plasma were increased.This response was further augmented with DGAT1 inhibitor PF-04620110 treated wildtype mice.Furthermore,PF-04620110 was able to dose responsively increase GLP-1 and PYY,but blunt GIP at all doses of PF-04620110 during lipid challenge.Combination treatment of PF-04620110 and Sitagliptin in wildtype mice during a lipid challenge synergistically enhanced postprandial levels of active GLP-1.In contrast,in a combination study with Orlistat,the ability of PF-04620110 to elicit an enhanced incretin response was abrogated.To further explore this observation,GPR119 knockout mice were evaluated.In response to a lipid challenge,GPR119 knockout mice exhibited no increase in active or total GLP-1 and PYY.However,PF-04620110 was able to increase total GLP-1 and PYY in GPR119 knockout mice as compared to vehicle treated wildtype mice.CONCLUSION Collectively,these data provide some insight into the mechanism by which inhibition of DGAT1 enhances intestinal hormone release.
基金Foundation item:The National Key Research and Development Program of China under contract No.2016YFC1402102the Central Public-interest Scientific Institution Basal Research Fund,CAFS under contract Nos 2020TD19 and 2020TD27+4 种基金the Major Scientific and Technological Innovation Project of Shandong Provincial Key Research and Development Program under contract 2019JZZY020706the International Exchange and Cooperation in Agriculture,Ministry of Agriculture and Rural Affairs of China-Science,Technology and Innovation Cooperation in Aquaculture with Tropical Countries along the Belt and RoadChina Agriculture Research System under contract No.CARS-50the Taishan Scholars Funding and Talent Projects of Distinguished Scientific Scholars in Agriculturethe National Ten Thousand Youth Talents Plan of 2014 under contract No.W02070268.
文摘Triacylglycerols(triglycerides,TAGs)are the major carbon and energy storage forms in various organisms,and important components of cellular membranes and signaling molecules;they have essential functions in multiple physiological processes and stress regulation.Acyl-CoA:diacylglycerol acyltransferase(DGAT)catalyzes the final and only committed acylation step in the synthesis of TAGs in eukaryotes.The present work identified and isolated a novel gene,UpDGAT1,from the green tide alga Ulva prolifera.The activity of UpDGAT1 was confirmed by heterologous expression in a Saccharomyces cerevisiae TAG-deficient quadruple mutant.Results of thin-layer chromatography and BODIPY staining indicated that UpDGAT1 was able to restore TAG synthesis and lipid body formation in the yeast.Lipid analysis of yeast cells revealed that UpDGAT1 showed broad substrate specificity,accepting saturated as well as mono-and polyunsaturated acyl-CoAs as substrates.High salinity and high temperature stresses increased UpDGAT1 expression and TAG accumulation in U.prolifera.The present study provides clues to the functions of UpDGAT1 in TAG accumulation in,and stress adaptation of,U.prolifera.
文摘Cultivated peanut is one of the primary sources of vegetable oil and protein in developing countries. DG〉A73 family in peanut cotyledons has no membrane-bound regions suggesting that cytosol is one of the sites for triacylglycerol （TAG） biosynthesis in oilseeds. According to functional annotation and classification of 5 cDNA libraries, 12 unigenes were found with relation of peanut DGAT3 in different organs. Three clones of unigenes, OCP- contig168t OCPcontig12101-3 and OCPcontigl2388-1 were selected for sequencing. Full length sequence of DGAT3 was obtained, showing over 98% sequence similarity with peanut DGAT3 gene AY875644 or EU183333. Upon cluster analysis, DGAT3 of 40 culti- vars were divided into 3 types, namely AhDGATS-1, AhDGAT3-2 and AhDGAT3-3. Coding regions are 1023, 1038 and 1026 base pairs which encoded proteins with 340-, 345- and 341-amino acids, respectively. DGAT3-3 might be a novel gene type among the DGAT3 family which provides great help for studying DGAT3 gene evolution in peanut.
文摘Microalgal oils, depending on their degree of unsaturation, can be utilized as either nutritional supplements or fuels; thus, a feedstock with genetically designed and tunable degree of unsaturation is desirable to maximize process efficiency and product versatility. Systematic profiling of ex vivo （in yeast）, in vitro, and in vivo activities of type-2 diacylglycerol acyltransferases in Nannochloropsis oceanica （NoDGAT2s or NoDGTTs）, via reverse genetics, revealed that NoDGAT2A prefers saturated fatty acids （SFAs）, NoDGAT2D prefers monounsaturated fatty acids （MUFAs）, and NoDGAT2C exhibits the strongest activity toward polyunsaturated fatty acids （PUFAs）. As NoDGAT2A, 2C, and 2D originated from the green alga, red alga, and eukaryotic host ancestral participants of secondary endosymbiosis, respectively, a mecha- nistic model of oleaginousness was unveiled, in which the indigenous and adopted NoDGAT2s formulated functional complementarity and specific transcript abundance ratio that underlie a rigid SFA：MUFA：PUFA hierarchy in triacylglycerol （TAG）. By rationally modulating the ratio of NoDGAT2A＇：2C^D transcripts, a bank of N. oceanica strains optimized for nutritional supplement or fuel production with a wide range of degree of unsaturation were created, in which proportion of SFAs, MUFAs, and PUFAs in TAG varied by 1.3-, 3.7-, and 11.2-fold, respectively. This established a novel strategy to simultaneously improve productivity and quality of oils from industrial microalgae.
基金Science and Technology Development Program of Jilin Province(201205099)
文摘Objective To identify the active compounds from the barks of Betula platyphylla for inhibitory on diacylglycerol acyltransferase（DGAT1）.Methods Bioassay-guided fractionation resulted in the isolation of DGAT1 inhibitory activity of lupane triterpenes.Results Ten compounds were identified as lupenone（1）,lupeol（2）,betulinic acid（3）,betulinaldehyde（4）,betulin（5）,3-deoxybetulonic acid（6）,glochidonol（7）,lup-20/29-ene-1β/3β-diol（8）,3α-hydroxy-lup-20（29）-en-23,28-dioic acid（9）,and 3α,11α-dihydroxy-23-oxo-lup-20（29）-en-28-oic acid（10）.Compounds 3-6,9,and 10 inhibited DGAT1 with IC50 values ranging from（11.2±0.3）to（38.6±1.2）μmol/L.Conclusion Compounds 6,9,and 10 are first isolated from the barks of B.platyphylla.,and compounds 3-6,9,and 10 from the barks of B.platyphylla are responsible for the inhibition on DGAT1.
基金supported by the National Natural Science Foundation of China (30770224)the National Basic Research Program of China (2011CBA00901)
文摘Two cDNAs encoding putative type 1 acyl-CoA： diacylglycerol acyltransferases （DGAT1, EC 2.3.1.20）, were cloned from Tetraena mongolica Maxim., an extreme xerophyte with high oil content in the stems. The 1,488-bp and 1,485-bp of the open reading frame （ORF） of the two cDNAs, designated as TmDGAT1a and TmDGAT1b, were both predicted to encode proteins of 495 and 494 amino acids, respectively. Southern blot analysis revealed that TmDGAT1a and TmDGAT1b both had low copy numbers in the T. mongolica genome. In addition to ubiquitous expression with different intensity in different tissues, including stems, leaves and roots, TmDGAT1a and TmDGAT1b, were found to be strongly induced by high salinity, drought and osmotic stress, resulting in a remarkable increase of triacylglycerol （TAG） accumulation in T. mongolica plantlets. TmDGAT1a and TmDGAT1b activities were confirmed in the yeast H1246 quadruple mutant （DGA1, LRO1, ARE1, ARE2） by restoring DGAT activity of the mutant host to produce TAG. Overexpression of TmDGAT1a and TmDGAT1b in soybean hairy roots as well as in T. mongolica calli both resulted in an increase in oil content （ranging from 37% to 108%）, accompanied by altered fatty acid profiles.
