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
AIM:To report that Lpcat1 plays an important role in regulating lipopolysaccharide (LPS) inducible gene tran-scription. METHODS:Gene expression in Murine Lung Epithelial MLE-12 cells with LPS treatment or Haemophilus ...AIM:To report that Lpcat1 plays an important role in regulating lipopolysaccharide (LPS) inducible gene tran-scription. METHODS:Gene expression in Murine Lung Epithelial MLE-12 cells with LPS treatment or Haemophilus influenza and Escherichia coli infection was analyzed by employing quantitative Reverse Transcription Polymerase Chain Reaction techniques. Nucleofection was used to deliver Lenti-viral system to express or knock down Lpcat1 in MLE cells. Subcellular protein fractionation and Western blotting were utilized to study Lpcat1 nuclear relocation. RESULTS:Lpcat1 translocates into the nucleus from thecytoplasm in murine lung epithelia (MLE) after LPS treatment. Haemophilus influenza and Escherichia coli , two LPS-containing pathogens that cause pneumonia, triggered Lpcat1 nuclear translocation from the cytoplasm. The LPS inducible gene expression profile was determined by quantitative reverse transcription polymerase chain reaction after silencing Lpcat1 or overexpression of the enzyme in MLE cells. We detected that 17 out of a total 38 screened genes were upregulated, 14 genes were suppressed, and 7 genes remained unchanged in LPS treated cells in comparison to controls. Knockdown of Lpcat1 by shRNA dramatically changed the spectrum of the LPS inducible gene transcription, as 18 genes out of 38 genes were upregulated, of which 20 genes were suppressed or unchanged. Notably, in Lpcat1 overex-pressed cells, 25 genes out of 38 genes were reduced in the setting of LPS treatment.CONCLUSION:These observations suggest that Lpcat1 relocates into the nucleus in response to bacterial infection to differentially regulate gene transcriptional repression.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
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
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Supported by A United States National Institutes of Health R01 grant HL091916 to Zhao Yan American Heart Association grant 12SDG12040330 to Zou C, in part
文摘AIM:To report that Lpcat1 plays an important role in regulating lipopolysaccharide (LPS) inducible gene tran-scription. METHODS:Gene expression in Murine Lung Epithelial MLE-12 cells with LPS treatment or Haemophilus influenza and Escherichia coli infection was analyzed by employing quantitative Reverse Transcription Polymerase Chain Reaction techniques. Nucleofection was used to deliver Lenti-viral system to express or knock down Lpcat1 in MLE cells. Subcellular protein fractionation and Western blotting were utilized to study Lpcat1 nuclear relocation. RESULTS:Lpcat1 translocates into the nucleus from thecytoplasm in murine lung epithelia (MLE) after LPS treatment. Haemophilus influenza and Escherichia coli , two LPS-containing pathogens that cause pneumonia, triggered Lpcat1 nuclear translocation from the cytoplasm. The LPS inducible gene expression profile was determined by quantitative reverse transcription polymerase chain reaction after silencing Lpcat1 or overexpression of the enzyme in MLE cells. We detected that 17 out of a total 38 screened genes were upregulated, 14 genes were suppressed, and 7 genes remained unchanged in LPS treated cells in comparison to controls. Knockdown of Lpcat1 by shRNA dramatically changed the spectrum of the LPS inducible gene transcription, as 18 genes out of 38 genes were upregulated, of which 20 genes were suppressed or unchanged. Notably, in Lpcat1 overex-pressed cells, 25 genes out of 38 genes were reduced in the setting of LPS treatment.CONCLUSION:These observations suggest that Lpcat1 relocates into the nucleus in response to bacterial infection to differentially regulate gene transcriptional repression.
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.
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.
