BACKGROUND Advanced glycation end products(AGEs)are diabetic metabolic toxic products that cannot be ignored.Nε-(carboxymethyl)lysine(CML),a component of AGEs,could increase macrophage lipid uptake,promote foam cell ...BACKGROUND Advanced glycation end products(AGEs)are diabetic metabolic toxic products that cannot be ignored.Nε-(carboxymethyl)lysine(CML),a component of AGEs,could increase macrophage lipid uptake,promote foam cell formation,and thereby accelerate atherosclerosis.The receptor for AGEs(RAGE)and cluster of differentiation 36(CD36)were the receptors of CML.However,it is still unknown whether RAGE and CD36 play key roles in CML-promoted lipid uptake.AIM Our study aimed to explore the role of RAGE and CD36 in CML-induced macrophage lipid uptake.METHODS In this study,we examined the effect of CML on lipid uptake by Raw264.7 macrophages.After adding 10 mmol/L CML,the lipid accumulation in macrophages was confirmed by oil red O staining.Expression changes of CD36 and RAGE were detected with immunoblotting and quantitative real-time polymerase chain reaction.The interaction between CML with CD36 and RAGE was verified by immunoprecipitation.We synthesized a novel N-succinimidyl-4-18Ffluorobenzoate-CML radioactive probe.Radioactive receptor-ligand binding assays were performed to test the binding affinity between CML with CD36 and RAGE.The effects of blocking CD36 or RAGE on CML-promoting lipid uptake were also detected.RESULTS The study revealed that CML significantly promoted lipid uptake by macrophages.Immunoprecipitation and radioactive receptor-ligand binding assays indicated that CML could specifically bind to both CD36 and RAGE.CML had a higher affinity for CD36 than RAGE.ARG82,ASN71,and THR70 were the potential interacting amino acids that CD36 binds to CML Anti-CD36 and anti-RAGE could block the uptake of CML by macrophages.The lipid uptake promotion effect of CML was significantly attenuated after blocking CD36 or RAGE.CONCLUSION Our results suggest that the binding of CML with CD36 and RAGE promotes macrophage lipid uptake.展开更多
BACKGROUND Myocardial remodeling is a key factor in the progression of cardiovascular disease to the end stage.In addition to myocardial infarction or stress overload,dietary factors have recently been considered asso...BACKGROUND Myocardial remodeling is a key factor in the progression of cardiovascular disease to the end stage.In addition to myocardial infarction or stress overload,dietary factors have recently been considered associated with myocardial remodeling.Nε-(carboxymethyl)lysine(CML)is a representative foodborne toxic product,which can be ingested via daily diet.Therefore,there is a marked need to explore the effects of dietary CML on the myocardium.AIM To explore the effects of dietary CML(dCML)on the heart.METHODS C57 BL/6 mice were divided into a control group and a dCML group.The control group and the dCML group were respectively fed a normal diet or diet supplemented with CML for 20 wk.Body weight and blood glucose were recorded every 4 wk.^(18)F-fluorodeoxyglucose(FDG)was used to trace the glucose uptake in mouse myocardium,followed by visualizing with micro-positron emission tomography(PET).Myocardial remodeling and glucose metabolism were also detected.In vitro,H9C2 cardiomyocytes were added to exogenous CML and cultured for 24 h.The effects of exogenous CML on glucose metabolism,collagen I expression,hypertrophy,and apoptosis of cardiomyocytes were analyzed.RESULTS Our results suggest that the levels of fasting blood glucose,fasting insulin,and serum CML were significantly increased after 20 wk of dCML.Micro-PET showed that ^(18)F-FDG accumulated more in the myocardium of the dCML group than in the control group.Histological staining revealed that dCML could lead to myocardial fibrosis and hypertrophy.The indexes of myocardial fibrosis,apoptosis,and hypertrophy were also increased in the dCML group,whereas the activities of glucose metabolism-related pathways and citrate synthase(CS)were significantly inhibited.In cardiomyocytes,collagen I expression and cellular size were significantly increased after the addition of exogenous CML.CML significantly promoted cellular hypertrophy and apoptosis,while pathways involved in glucose metabolism and level of Cs mRNA were significantly inhibited.CONCLUSION This study reveals that dCML alters myocardial glucose metabolism and promotes myocardial remodeling.展开更多
Diabetes-associated cognitive dysfunction has already been attracted considerable attention.Advanced glycation end products(AGEs)from daily diets are thought to be a vital contributor to the development of this diseas...Diabetes-associated cognitive dysfunction has already been attracted considerable attention.Advanced glycation end products(AGEs)from daily diets are thought to be a vital contributor to the development of this diseases.However,the effect of one of the best-characterized exogenous AGEs N^(ε)-(carboxymethyl)lysine(CML)on cognitive function is not fully reported.In the present study,diabetical Goto-Kakizaki(GK)rats were treated with free CML for 8-weeks.It was found that oral consumption of exogenous CML significantly aggravated diabetes-associated cognitive dysfunction in behavioral test.In details,exogenous CML increased levels of oxidative stress,promoted the activation of glial cells in the brain,up-regulated the release of inflammatory cytokines interleukin-6,inhibited the protein expression of the brain-derived neurotrophic factor and thus led to neuroinflammation.Furthermore,exogenous CML promoted the amyloidogenesis in the brain of GK rats,and inhibited the expression of GLUT4.Additionally,several tricarboxylic acid cycle and glutamate-glutamine/γ-aminobutyric acid cycle intermediates including pyruvate,succinic acid,glutamine,glutamate were significantly changed in brain of GK rats treated with exogenous free CML.In conclusion,exogenous free CML is a potentially noxious compounds led to aggravated diabetes-associated cognitive dysfunction which could be possibly explained by its effects on neuroinflammation,energy and neurotransmitter amino acid homeostasis.展开更多
Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube developme...Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube development, C57BL/6 female mice were fed for 4 weeks with com- mercial food containing 3% advanced glycation end product bovine serum albumin （AGE-BSA） or 3% bovine serum albumin （BSA） as a control. After mating mice, oxidative stress markers including malondialdehyde and H202 were measured at embryonic day 7.5 （E7.5） of ges- tation, and the level of intracellular reactive oxygen species （ROS） in embryonic cells was determined at E8.5. In addition to evaluating NTDs, an enzyme-linked immunosorbent assay was used to determine the effect of embryonic protein administration on the N-（carboxymethyl） lysine reactivity of acid and carboxyethyl lysine antibodies at E10.5. The results showed a remarkable increase in the incidence of NTDs at El0.5 in embryos of mice fed with AGE-BSA （no hyperglycemia） compared with control mice. Moreover, embryonic protein administration resulted in a noticeable increase in the reactivity of N-（carboxymethyl） lysine and N（ε）-（carboxyethyl） lysine antibodies. Malondialdehyde and H2O2 levels in embryonic cells were increased at E7.5, followed by increased intracellular ROS levels at E8.5. Vitamin E supplementation could partially recover these phenomena. Collectively, these results suggest that AGE-BSA could induce NTDs in the absence of hyperglycemia by an underlying mechanism that is at least partially associated with its capacity to increase embryonic oxidative stress levels.展开更多
目的:研究糖基化终末产物(advanced glycation end products,AGE)及其受体(receptor for advanced glycation end products,RAGE)在胃肠道中的分布,为进一步探索其在慢性糖尿病胃肠功能紊乱中的作用奠定基础.方法:分别对成年Wistar大鼠...目的:研究糖基化终末产物(advanced glycation end products,AGE)及其受体(receptor for advanced glycation end products,RAGE)在胃肠道中的分布,为进一步探索其在慢性糖尿病胃肠功能紊乱中的作用奠定基础.方法:分别对成年Wistar大鼠食管、胃、十二指肠、空肠、回肠、结肠及直肠组织进行AGE及RAGE免疫组织化学染色.结果:(1)食管:AGE及RAGE主要分布在横纹肌的肌细胞及黏膜的鳞状上皮细胞;(2)胃:AGE在壁细胞为强阳性.RAGE在主细胞、肥大细胞、神经细胞为强阳性,在壁细胞为中等强度阳性,在表面黏液细胞为弱阳性;(3)小肠:AGE及RAGE在绒毛及固有层上皮细胞为阳性或强阳性.RAGE在肠道的神经细胞亦为强阳性;(4)结肠及直肠:AGE及RAGE在黏膜上皮细胞为弱阳性,RAGE在神经细胞为强阳性.结论:AGE及RAGE广泛分布于肠道上皮细胞及食管的横纹肌细胞,AGE亦分布于胃的壁细胞,RAGE亦分布于胃的壁细胞、主细胞、表面黏液细胞、肥大细胞及胃肠道的神经细胞.展开更多
建立了基于实时直接分析质谱(direct analysis in real time mass spectrometry,DART-MS)快速测定牦牛肉中羧甲基赖氨酸[N^(ε)-(carboxymethyl)lysine,CML]、羧乙基赖氨酸[N^(ε)-(carboxyethyl)lysine,CEL]含量的方法,并探究了苦荞、...建立了基于实时直接分析质谱(direct analysis in real time mass spectrometry,DART-MS)快速测定牦牛肉中羧甲基赖氨酸[N^(ε)-(carboxymethyl)lysine,CML]、羧乙基赖氨酸[N^(ε)-(carboxyethyl)lysine,CEL]含量的方法,并探究了苦荞、藤椒抗氧化食品原料对牦牛肉中羧基赖氨酸含量的影响。在正离子模式下,采用三重四级杆多反应监测模式,对CML在DART-MS的裂解机制进行了系统研究,并对DART离子源的气体解吸温度、栅网电极电压等试验条件进行了优化。结果表明,CML质量浓度在1~50μg/mL与峰面积呈现良好线性关系。CML的检测限为0.1μg/g,定量限为0.5μg/g,回收率为100.77%~117.36%,精密度为8.22%~9.87%。该方法能在2 min内完成8个/批样品中CML、CEL的快速检测。加入牦牛肉质量50%的苦荞粉后,牦牛肉中CML、CEL含量分别降低7.72%和1.46%;加入牦牛肉质量50%的藤椒粉后牦牛肉中CML降低14.51%,CEL增加7.35%。研究结果可为开发高品质牦牛肉产品提供理论依据。展开更多
基金Supported by The National Natural Science Foundation of China,No.82070455Natural Science Foundation of Jiangsu Province,No.BK20201225Medical Innovation Team Project of Jiangsu Province,No.CXTDA2017010。
文摘BACKGROUND Advanced glycation end products(AGEs)are diabetic metabolic toxic products that cannot be ignored.Nε-(carboxymethyl)lysine(CML),a component of AGEs,could increase macrophage lipid uptake,promote foam cell formation,and thereby accelerate atherosclerosis.The receptor for AGEs(RAGE)and cluster of differentiation 36(CD36)were the receptors of CML.However,it is still unknown whether RAGE and CD36 play key roles in CML-promoted lipid uptake.AIM Our study aimed to explore the role of RAGE and CD36 in CML-induced macrophage lipid uptake.METHODS In this study,we examined the effect of CML on lipid uptake by Raw264.7 macrophages.After adding 10 mmol/L CML,the lipid accumulation in macrophages was confirmed by oil red O staining.Expression changes of CD36 and RAGE were detected with immunoblotting and quantitative real-time polymerase chain reaction.The interaction between CML with CD36 and RAGE was verified by immunoprecipitation.We synthesized a novel N-succinimidyl-4-18Ffluorobenzoate-CML radioactive probe.Radioactive receptor-ligand binding assays were performed to test the binding affinity between CML with CD36 and RAGE.The effects of blocking CD36 or RAGE on CML-promoting lipid uptake were also detected.RESULTS The study revealed that CML significantly promoted lipid uptake by macrophages.Immunoprecipitation and radioactive receptor-ligand binding assays indicated that CML could specifically bind to both CD36 and RAGE.CML had a higher affinity for CD36 than RAGE.ARG82,ASN71,and THR70 were the potential interacting amino acids that CD36 binds to CML Anti-CD36 and anti-RAGE could block the uptake of CML by macrophages.The lipid uptake promotion effect of CML was significantly attenuated after blocking CD36 or RAGE.CONCLUSION Our results suggest that the binding of CML with CD36 and RAGE promotes macrophage lipid uptake.
基金Supported by the National Natural Science Foundation of China,No.82070455Natural Science Foundation of Jiangsu Province,No.BK20201225+1 种基金Medical Innovation Team Project of Jiangsu Province,No.CXTDA2017010Research and Innovation Funding Project for College Students in Experimental Animal Center of Jiangsu University。
文摘BACKGROUND Myocardial remodeling is a key factor in the progression of cardiovascular disease to the end stage.In addition to myocardial infarction or stress overload,dietary factors have recently been considered associated with myocardial remodeling.Nε-(carboxymethyl)lysine(CML)is a representative foodborne toxic product,which can be ingested via daily diet.Therefore,there is a marked need to explore the effects of dietary CML on the myocardium.AIM To explore the effects of dietary CML(dCML)on the heart.METHODS C57 BL/6 mice were divided into a control group and a dCML group.The control group and the dCML group were respectively fed a normal diet or diet supplemented with CML for 20 wk.Body weight and blood glucose were recorded every 4 wk.^(18)F-fluorodeoxyglucose(FDG)was used to trace the glucose uptake in mouse myocardium,followed by visualizing with micro-positron emission tomography(PET).Myocardial remodeling and glucose metabolism were also detected.In vitro,H9C2 cardiomyocytes were added to exogenous CML and cultured for 24 h.The effects of exogenous CML on glucose metabolism,collagen I expression,hypertrophy,and apoptosis of cardiomyocytes were analyzed.RESULTS Our results suggest that the levels of fasting blood glucose,fasting insulin,and serum CML were significantly increased after 20 wk of dCML.Micro-PET showed that ^(18)F-FDG accumulated more in the myocardium of the dCML group than in the control group.Histological staining revealed that dCML could lead to myocardial fibrosis and hypertrophy.The indexes of myocardial fibrosis,apoptosis,and hypertrophy were also increased in the dCML group,whereas the activities of glucose metabolism-related pathways and citrate synthase(CS)were significantly inhibited.In cardiomyocytes,collagen I expression and cellular size were significantly increased after the addition of exogenous CML.CML significantly promoted cellular hypertrophy and apoptosis,while pathways involved in glucose metabolism and level of Cs mRNA were significantly inhibited.CONCLUSION This study reveals that dCML alters myocardial glucose metabolism and promotes myocardial remodeling.
基金supported by the National Natural Science Foundation of China(32302258,32172317)Changsha Municipal Natural Science Foundation(kq2202223).
文摘Diabetes-associated cognitive dysfunction has already been attracted considerable attention.Advanced glycation end products(AGEs)from daily diets are thought to be a vital contributor to the development of this diseases.However,the effect of one of the best-characterized exogenous AGEs N^(ε)-(carboxymethyl)lysine(CML)on cognitive function is not fully reported.In the present study,diabetical Goto-Kakizaki(GK)rats were treated with free CML for 8-weeks.It was found that oral consumption of exogenous CML significantly aggravated diabetes-associated cognitive dysfunction in behavioral test.In details,exogenous CML increased levels of oxidative stress,promoted the activation of glial cells in the brain,up-regulated the release of inflammatory cytokines interleukin-6,inhibited the protein expression of the brain-derived neurotrophic factor and thus led to neuroinflammation.Furthermore,exogenous CML promoted the amyloidogenesis in the brain of GK rats,and inhibited the expression of GLUT4.Additionally,several tricarboxylic acid cycle and glutamate-glutamine/γ-aminobutyric acid cycle intermediates including pyruvate,succinic acid,glutamine,glutamate were significantly changed in brain of GK rats treated with exogenous free CML.In conclusion,exogenous free CML is a potentially noxious compounds led to aggravated diabetes-associated cognitive dysfunction which could be possibly explained by its effects on neuroinflammation,energy and neurotransmitter amino acid homeostasis.
基金supported by the grant from Shaanxi Technology Committee of China,No.2013JM4001the China Scholarship Council(CSC)
文摘Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube development, C57BL/6 female mice were fed for 4 weeks with com- mercial food containing 3% advanced glycation end product bovine serum albumin （AGE-BSA） or 3% bovine serum albumin （BSA） as a control. After mating mice, oxidative stress markers including malondialdehyde and H202 were measured at embryonic day 7.5 （E7.5） of ges- tation, and the level of intracellular reactive oxygen species （ROS） in embryonic cells was determined at E8.5. In addition to evaluating NTDs, an enzyme-linked immunosorbent assay was used to determine the effect of embryonic protein administration on the N-（carboxymethyl） lysine reactivity of acid and carboxyethyl lysine antibodies at E10.5. The results showed a remarkable increase in the incidence of NTDs at El0.5 in embryos of mice fed with AGE-BSA （no hyperglycemia） compared with control mice. Moreover, embryonic protein administration resulted in a noticeable increase in the reactivity of N-（carboxymethyl） lysine and N（ε）-（carboxyethyl） lysine antibodies. Malondialdehyde and H2O2 levels in embryonic cells were increased at E7.5, followed by increased intracellular ROS levels at E8.5. Vitamin E supplementation could partially recover these phenomena. Collectively, these results suggest that AGE-BSA could induce NTDs in the absence of hyperglycemia by an underlying mechanism that is at least partially associated with its capacity to increase embryonic oxidative stress levels.
文摘目的:研究糖基化终末产物(advanced glycation end products,AGE)及其受体(receptor for advanced glycation end products,RAGE)在胃肠道中的分布,为进一步探索其在慢性糖尿病胃肠功能紊乱中的作用奠定基础.方法:分别对成年Wistar大鼠食管、胃、十二指肠、空肠、回肠、结肠及直肠组织进行AGE及RAGE免疫组织化学染色.结果:(1)食管:AGE及RAGE主要分布在横纹肌的肌细胞及黏膜的鳞状上皮细胞;(2)胃:AGE在壁细胞为强阳性.RAGE在主细胞、肥大细胞、神经细胞为强阳性,在壁细胞为中等强度阳性,在表面黏液细胞为弱阳性;(3)小肠:AGE及RAGE在绒毛及固有层上皮细胞为阳性或强阳性.RAGE在肠道的神经细胞亦为强阳性;(4)结肠及直肠:AGE及RAGE在黏膜上皮细胞为弱阳性,RAGE在神经细胞为强阳性.结论:AGE及RAGE广泛分布于肠道上皮细胞及食管的横纹肌细胞,AGE亦分布于胃的壁细胞,RAGE亦分布于胃的壁细胞、主细胞、表面黏液细胞、肥大细胞及胃肠道的神经细胞.
文摘建立了基于实时直接分析质谱(direct analysis in real time mass spectrometry,DART-MS)快速测定牦牛肉中羧甲基赖氨酸[N^(ε)-(carboxymethyl)lysine,CML]、羧乙基赖氨酸[N^(ε)-(carboxyethyl)lysine,CEL]含量的方法,并探究了苦荞、藤椒抗氧化食品原料对牦牛肉中羧基赖氨酸含量的影响。在正离子模式下,采用三重四级杆多反应监测模式,对CML在DART-MS的裂解机制进行了系统研究,并对DART离子源的气体解吸温度、栅网电极电压等试验条件进行了优化。结果表明,CML质量浓度在1~50μg/mL与峰面积呈现良好线性关系。CML的检测限为0.1μg/g,定量限为0.5μg/g,回收率为100.77%~117.36%,精密度为8.22%~9.87%。该方法能在2 min内完成8个/批样品中CML、CEL的快速检测。加入牦牛肉质量50%的苦荞粉后,牦牛肉中CML、CEL含量分别降低7.72%和1.46%;加入牦牛肉质量50%的藤椒粉后牦牛肉中CML降低14.51%,CEL增加7.35%。研究结果可为开发高品质牦牛肉产品提供理论依据。
