In the present study, the effect of 5-aminoimidazole-4-carboxamide ribonucleoside （AICAR） on long-chain fatty acid oxidation by hepatocytes isolated from suckled neonatal pig liver （a low ketogenic and lipogenic ti...In the present study, the effect of 5-aminoimidazole-4-carboxamide ribonucleoside （AICAR） on long-chain fatty acid oxidation by hepatocytes isolated from suckled neonatal pig liver （a low ketogenic and lipogenic tissue） was tested Incubation of hepatocytes with AICAR （0.5 raM） in the presence of ] mM of carnitine and 10 mM of glucose for 1 hour at 37℃ had no significant effect on total [1-14C]-palrnitate （0.5 mM） oxidation （14CO2 and 14C-Acid soluble products （ASP））. Consistent with the fatty acid oxidation, carnitine palmitoyltransferase I activity and inhibition of its activity by malonyI-CoA （10 MM） assayed in cell homogenate also remained constant. However, addition of AICAR to the hepatocytes decreased 14CO2 production by 18% compared to control （p 〈 0.06）. The reduction of labeled carboxylic carbon accumulated in C02 caused a significant difference in distribution of oxidative products between 14C02 and 14C-ASP （p 〈 0.03） compared with the control. It was also noticed that acetyI-CoA carboxylase （ACC） was increased by AICAR （p 〈 0.03）, indicating that ACC might drive acetyI-CoA toward fatty acid synthesis pathway and induce an increase in distribution of fatty acid carbon to 14C-ASP. Addition of insulin to hepatocyte incubations with AICAR did not change the oxidative product distribution between CO2 and ASP, but further promoted ACC activity. The increased ACC activity was 70% higher than in the control group when citrate was absent in the reaction medium and was 30% higher when citrate was present in the medium. Our results suggest that AICAR may affect the distribution of metabolic products from fatty acid oxidation by changing ACC activity in hepatocyte isolated from suckled neonatal piglets; however, the basis for the increase in ACC activity elicited by AICAR is not apparent.展开更多
Growing evidence suggests that exercise can provide neuroprotection by improving mitochondrial quality control(MQC)on the aged brain.Adenosine 5′-monophosphate(AMP)-activated protein kinase(AMPK)signaling responsiven...Growing evidence suggests that exercise can provide neuroprotection by improving mitochondrial quality control(MQC)on the aged brain.Adenosine 5′-monophosphate(AMP)-activated protein kinase(AMPK)signaling responsiveness declines with aging.However,whether AMPK plays a role in the exercise-mediated improvement of memory and MQC in the aged hippocampus remains to be established.5-Aminoimidazole 4-carboxamide ribonucleoside(AICAR),a pharmacological agonist of AMPK,has been proposed to be an exercise mimetic recently.However,it has not been clarified whether AICAR could mimic the effects of exercise on the aged hippocampus through improvement of MQC.In this study,AICAR(AMPK agonist)and Compound C(AMPK inhibitor)were used to investigate if AMPK plays a key role in exercise-induced improvement of MQC and if AICAR could act as an exercise mimetic through improvement of MQC in aged hippocampus.Both exercise and AICAR improved the memory of aged mice and increased AMPK phosphorylation in the aged hippocampus.Exercise,but not AICAR,improved mitochondrial respiratory function in the aged hippocampus and increased the microtubule associated protein 1 light chain 3(LC3)-II/LC3-I ratio and the protein expression of LC3-II and autophagy related protein 7(ATG7)in the lysate of whole hippocampal tissue.Both exercise and AICAR increased the ratio of LC3-II/LC3-I and the protein expression of LC3-II in the mitochondrial fractions of the hippocampus.Regarding mitochondrial dynamics,neither exercise training nor AICAR changed the protein level of mitofusin 2(Mfn2).Exercise,but not AICAR,increased the protein level of dynamin-related protein 1(Drp1).Furthermore,both exercise training and AICAR increased the protein level of peroxisome proliferator-activated receptor γ coactivator 1α(PGC-1α),a modulator of mitochondrial biogenesis.Compound C abolished the exercise-induced effects on memory in aged mice,AMPK phosphorylation,autophagy,mitophagy,and mitochondrial fission in the aged hippocampus.However,Compound C did not reverse the exercise-induced increase in PGC-1α protein levels in the aged hippocampus.Our data provide evidence that AMPK plays an important role in the exercise-induced improvement of memory and MQC in the hippocampus of aged mice.Importantly,we demonstrated for the first time that AICAR could partially mimetic the beneficial effects of endurance exercise on memory and MQC in the hippocampus of aged mice,and thus may be a promising exercise mimetic for counteracting brain aging.展开更多
New ribonucleoside analogues containing thio-substituted 1,3,4-triazole as heterocyclic base have been synthesized via condensation of the central intermediate 1 with various acids, esters, amides, and anhydrides in a...New ribonucleoside analogues containing thio-substituted 1,3,4-triazole as heterocyclic base have been synthesized via condensation of the central intermediate 1 with various acids, esters, amides, and anhydrides in anhydrous solvent followed by deprotection.展开更多
An approximate method has been established to calculate the depth of the potential acting on an electron in a molecule at the saddle point along a chemical bond, denoted by Dpb. It is a new indicator which can be used...An approximate method has been established to calculate the depth of the potential acting on an electron in a molecule at the saddle point along a chemical bond, denoted by Dpb. It is a new indicator which can be used for predicting the strength of a chemical bond. In this work, as a practical application for demonstrating this method, we calculated the Dpb of deoxyribonucleosides and ribonucleosides along all C-H and N-H chemical bonds using the method. The results are in fair agreement with those results of previously reported experimental and theoretical observations,展开更多
基金supported by National Research Initiative Competitive Grant no. 2007-35206-17897 from the USDA National Institute of Food and Agriculture
文摘In the present study, the effect of 5-aminoimidazole-4-carboxamide ribonucleoside （AICAR） on long-chain fatty acid oxidation by hepatocytes isolated from suckled neonatal pig liver （a low ketogenic and lipogenic tissue） was tested Incubation of hepatocytes with AICAR （0.5 raM） in the presence of ] mM of carnitine and 10 mM of glucose for 1 hour at 37℃ had no significant effect on total [1-14C]-palrnitate （0.5 mM） oxidation （14CO2 and 14C-Acid soluble products （ASP））. Consistent with the fatty acid oxidation, carnitine palmitoyltransferase I activity and inhibition of its activity by malonyI-CoA （10 MM） assayed in cell homogenate also remained constant. However, addition of AICAR to the hepatocytes decreased 14CO2 production by 18% compared to control （p 〈 0.06）. The reduction of labeled carboxylic carbon accumulated in C02 caused a significant difference in distribution of oxidative products between 14C02 and 14C-ASP （p 〈 0.03） compared with the control. It was also noticed that acetyI-CoA carboxylase （ACC） was increased by AICAR （p 〈 0.03）, indicating that ACC might drive acetyI-CoA toward fatty acid synthesis pathway and induce an increase in distribution of fatty acid carbon to 14C-ASP. Addition of insulin to hepatocyte incubations with AICAR did not change the oxidative product distribution between CO2 and ASP, but further promoted ACC activity. The increased ACC activity was 70% higher than in the control group when citrate was absent in the reaction medium and was 30% higher when citrate was present in the medium. Our results suggest that AICAR may affect the distribution of metabolic products from fatty acid oxidation by changing ACC activity in hepatocyte isolated from suckled neonatal piglets; however, the basis for the increase in ACC activity elicited by AICAR is not apparent.
基金supported by grants from the National Natural Science Foundation of China(81301128,81771500,82202789,82205065)the 2022 Suzhou Health Youth Backbone Talent“National Tutorial System”Training Project(Qngg2022024)+2 种基金the Science and Technology Project of Suzhou City of China(SKJYD2021195)the Science,Technology and Innovation Commission of Shenzhen(JCYJ20220530165211026)the Postgraduate Research and Practice Innovation Program in Jiangsu Province(KYCX22_3157,KYCX24_3371,YCX25_3517).
文摘Growing evidence suggests that exercise can provide neuroprotection by improving mitochondrial quality control(MQC)on the aged brain.Adenosine 5′-monophosphate(AMP)-activated protein kinase(AMPK)signaling responsiveness declines with aging.However,whether AMPK plays a role in the exercise-mediated improvement of memory and MQC in the aged hippocampus remains to be established.5-Aminoimidazole 4-carboxamide ribonucleoside(AICAR),a pharmacological agonist of AMPK,has been proposed to be an exercise mimetic recently.However,it has not been clarified whether AICAR could mimic the effects of exercise on the aged hippocampus through improvement of MQC.In this study,AICAR(AMPK agonist)and Compound C(AMPK inhibitor)were used to investigate if AMPK plays a key role in exercise-induced improvement of MQC and if AICAR could act as an exercise mimetic through improvement of MQC in aged hippocampus.Both exercise and AICAR improved the memory of aged mice and increased AMPK phosphorylation in the aged hippocampus.Exercise,but not AICAR,improved mitochondrial respiratory function in the aged hippocampus and increased the microtubule associated protein 1 light chain 3(LC3)-II/LC3-I ratio and the protein expression of LC3-II and autophagy related protein 7(ATG7)in the lysate of whole hippocampal tissue.Both exercise and AICAR increased the ratio of LC3-II/LC3-I and the protein expression of LC3-II in the mitochondrial fractions of the hippocampus.Regarding mitochondrial dynamics,neither exercise training nor AICAR changed the protein level of mitofusin 2(Mfn2).Exercise,but not AICAR,increased the protein level of dynamin-related protein 1(Drp1).Furthermore,both exercise training and AICAR increased the protein level of peroxisome proliferator-activated receptor γ coactivator 1α(PGC-1α),a modulator of mitochondrial biogenesis.Compound C abolished the exercise-induced effects on memory in aged mice,AMPK phosphorylation,autophagy,mitophagy,and mitochondrial fission in the aged hippocampus.However,Compound C did not reverse the exercise-induced increase in PGC-1α protein levels in the aged hippocampus.Our data provide evidence that AMPK plays an important role in the exercise-induced improvement of memory and MQC in the hippocampus of aged mice.Importantly,we demonstrated for the first time that AICAR could partially mimetic the beneficial effects of endurance exercise on memory and MQC in the hippocampus of aged mice,and thus may be a promising exercise mimetic for counteracting brain aging.
文摘New ribonucleoside analogues containing thio-substituted 1,3,4-triazole as heterocyclic base have been synthesized via condensation of the central intermediate 1 with various acids, esters, amides, and anhydrides in anhydrous solvent followed by deprotection.
基金supported by the National Natural Science Foundation of China(Nos.21073080 and 21133005)
文摘An approximate method has been established to calculate the depth of the potential acting on an electron in a molecule at the saddle point along a chemical bond, denoted by Dpb. It is a new indicator which can be used for predicting the strength of a chemical bond. In this work, as a practical application for demonstrating this method, we calculated the Dpb of deoxyribonucleosides and ribonucleosides along all C-H and N-H chemical bonds using the method. The results are in fair agreement with those results of previously reported experimental and theoretical observations,
