The neuroendocrine hormone amylin, also known as islet amyloid polypeptide, is co-localized, co-packaged and cosecreted with insulin from adult pancreatic islet β cells to maintain glucose homeostasis. Specifically, ...The neuroendocrine hormone amylin, also known as islet amyloid polypeptide, is co-localized, co-packaged and cosecreted with insulin from adult pancreatic islet β cells to maintain glucose homeostasis. Specifically, amylin reduces secretion of nutrient-stimulated glucagon, regulates blood pressure with an effect on renin-angiotensin system, and delays gastric emptying. The physiological actions of human amylin attribute to the conformational α-helix monomers whereas the misfolding instable oligomers may be detrimental to the islet β cells and further transform to β-sheet fibrils as amyloid deposits. No direct evidence proves that the amylin fibrils in amyloid deposits cause diabetes. Here we also have performed a systematic review of human amylin gene changes and reported the S20 G mutation is minor in the development of diabetes. In addition to the metabolic effects, human amylin may modulate autoimmunity and innate inflammation through regulatory T cells to impact on both human type 1 and type 2 diabetes.展开更多
Alzheimer disease(AD) and typeⅡdiabetes mellitus(DM2) are the most common disease in aging people,with β-amyloid and amylin accumulation respectively.Studies have shown more and more correlations between these two d...Alzheimer disease(AD) and typeⅡdiabetes mellitus(DM2) are the most common disease in aging people,with β-amyloid and amylin accumulation respectively.Studies have shown more and more correlations between these two diseases,and amylin oligomerization in the brain provided a novel risk target for developing AD.Although cumulative studies reported that amylin aggregation induced cytotoxicity in pancreatic beta cells by altering Ca2+homeostasis,fewer studies investigated the effect of amylin on hippocampal neuron.To address this question,it was investigated the effect of amylin on primary cultured rat hippocampal neurons by calcium imaging and whole-cell patch clamp recording in this study,while the results revealed that human amylin(hAmylin) but not rat amylin or pramlintide(hAmylin analgue) produced a rapid increase in intracellular calcium in a dose dependent manner.This effect relied on extracellular calcium and not abolished by amylin receptor antagonist AC187.Additionally,the calcium increase induced by hAmylin was dependent onvoltage-gated Ca2+channels,especially L-type Ca2+channel activation.In whole-cell recording hAmylin could depolarize membrane potential and increase the cell exitability.Moreover,application of transient receptor potential vanilloid(TRPV) antagonist ruthenium red could abolish part of the intracellular calcium increase.Single cell RT-PCR revealed that TRPV4 mRNA expressed in most of the reactive neuron and selective TRPV4 antagonist HC067047 inhibited the intacellular calcium increasing.These results indicated that hAmylin aggregation precipitating on the neuron membrane activated TRPV4 channels and then triggered membrane voltage gated calcium channel opening followed by membrane depolarization,expressing that TRPV4 is a key molecular target for the cytotoxic effect of hAmylin on cultured neurons.展开更多
Objective:In the present study, the protein structure model of human amylin was generated to understand the protein's structure, function and mechanism of the action. Methods: The stereo chemical quality of the pr...Objective:In the present study, the protein structure model of human amylin was generated to understand the protein's structure, function and mechanism of the action. Methods: The stereo chemical quality of the protein model was checked by usingin silico analysis withSWISSMODEL,SOPMA,PROCHECK, ProSA andQMEAN servers. Results:The 66.7% residues in the core region of Ramachandran plot showing high accuracy of protein model and the QMEAN Z score of –6.57 indicates the overall model quality of amylin protein. Conclusions: These results may be helpful for further investigation on developing target molecules for amylin proteins that play a key role in type 2 diabetes.展开更多
Co-secretion with insulin,highly amyloidogenic human amylin is considered to contribute to the initiation and progression of diabetic heart complications,despite other situations such as hypertension and atheroscleros...Co-secretion with insulin,highly amyloidogenic human amylin is considered to contribute to the initiation and progression of diabetic heart complications,despite other situations such as hypertension and atherosclerosis.In response to insulin resistance,hyperinsulinemia,and consequently hyperamylinemia,is common in prediabetic patients,where highly concentrated amylin is prone to form amylin oligomers,which further assemble into fibrils and amyloids with high b-sheet content.The infusion and deposition of oligomeric amylin in myocytes cause a series of consequences,including cytosolic Ca^(2+)dysregulation,calmodulin activation,myocyte hypertrophy,and ventricular stiffness,eventually leading to heart failure.In this review,we present the latest reports of amylin-related heart complications,provide new insights,and state the underlying pathogenesis,diagnosis,possible treatment,and prevention of diabetic cardiomyopathy.展开更多
In the present study, we investigate effect of amylin on the insulin sensitivity of rat skeletal muscle extensor digitorum longus (EDL) using in vitro intact muscle incubation in combination with metabolic radioactive...In the present study, we investigate effect of amylin on the insulin sensitivity of rat skeletal muscle extensor digitorum longus (EDL) using in vitro intact muscle incubation in combination with metabolic radioactive labeling. The molecular basis of the amylin action was further examined using proteomic analysis. In particular, proteins of interest were characterized using an integrated microcharacterization procedure that involved in-gel trypsin digestion, organic solvent extraction, high performance liquid chromatography separation, microsequencing and microsequence analysis. We found that amylin significantly decreased the insulin-stimulated glucose incorporation into glycogen (p < 0.01) and produced a protein spot of approximately 20 ku in size. This amylin responsive protein (hereby designated as amylin responsive protein 1, APR1) was identified to be protein p20. Moreover, ARP1 spots on gels were found to consistently produce a corresponding radioactive spot on X-ray films in 32Pi but not in 35S-methionine labeling experiments. In conclusion, our results showed that in vitro amylin concomitantly evoked the production of ARP1 and caused insulin resistance in EDL muscle. It is suggested that protein p20 may be involved in amylin signal transduction and the appearance of ARP1 may be a step in a molecular pathway leading to the development of insulin resistance. ARP1 might therefore be a useful molecular marker for amylin action, insulin resistance and Type 2 diabetes.展开更多
目的探讨胰淀素(amylin)通过下丘脑室旁核(PVN)ERK通路对小鼠摄食行为的调控作用。方法将54只C57BL/6J小鼠随机分为多组开展实验。首先采用免疫荧光检测4只小鼠脑内ERK和降钙素受体(CTR)神经元的分布。通过化学损伤法建立PVN神经元损伤...目的探讨胰淀素(amylin)通过下丘脑室旁核(PVN)ERK通路对小鼠摄食行为的调控作用。方法将54只C57BL/6J小鼠随机分为多组开展实验。首先采用免疫荧光检测4只小鼠脑内ERK和降钙素受体(CTR)神经元的分布。通过化学损伤法建立PVN神经元损伤模型,将16只小鼠分为4组(每组4只):对照组(Ctrl)、鹅膏酸损毁组(IBO)、amylin组和amylin+IBO组,统计PVN区域ERK阳性神经元数量及摄食量。随后,将16只小鼠分为4组(每组4只):Ctrl组、amylin组、ERK拮抗剂U0126组、amylin+U0126组,通过Real-time PCR检测PVN即刻早期基因(c-fos)表达水平。免疫荧光检测Ctrl组和amylin组小鼠脑内p-ERK阳性神经元分布(每组4只)。最后,通过侧脑室注射,将18只小鼠随机分为3组(每组6只):Ctrl组、amylin组和amylin+受体拮抗剂AC187组,然后免疫荧光检测PVN区域p-ERK、神经型一氧化氮合酶(nNOS)及CTR免疫阳性神经元共表达,同步记录处理后3 h内的摄食量。结果ERK阳性神经元主要分布于视交叉上核(SCN)、弓状核(ARC)和蓝斑核(LC),而ERK和CTR共表达阳性神经元特异性富集于PVN(P<0.01)。PVN神经元损伤导致ERK阳性神经元数量减少(P<0.001),且阻断了amylin的抑食作用(P<0.001)。Amylin激活PVN区域c-fos基因表达(P<0.05),而该效应可被U0126抑制(P<0.05)。侧脑室注射amylin后,PVN中p-ERK、nNOS和CTR三标阳性神经元数量增加(P<0.05),添加AC187则阻断amylin的激活效应(P<0.01),并逆转amylin的抑食效应(1 h P=0.2218,2 h P=0.2218,3 h P=0.6974)。结论PVN中p-ERK神经元通过amylin受体依赖的ERK信号通路调控摄食行为。展开更多
文摘The neuroendocrine hormone amylin, also known as islet amyloid polypeptide, is co-localized, co-packaged and cosecreted with insulin from adult pancreatic islet β cells to maintain glucose homeostasis. Specifically, amylin reduces secretion of nutrient-stimulated glucagon, regulates blood pressure with an effect on renin-angiotensin system, and delays gastric emptying. The physiological actions of human amylin attribute to the conformational α-helix monomers whereas the misfolding instable oligomers may be detrimental to the islet β cells and further transform to β-sheet fibrils as amyloid deposits. No direct evidence proves that the amylin fibrils in amyloid deposits cause diabetes. Here we also have performed a systematic review of human amylin gene changes and reported the S20 G mutation is minor in the development of diabetes. In addition to the metabolic effects, human amylin may modulate autoimmunity and innate inflammation through regulatory T cells to impact on both human type 1 and type 2 diabetes.
文摘Alzheimer disease(AD) and typeⅡdiabetes mellitus(DM2) are the most common disease in aging people,with β-amyloid and amylin accumulation respectively.Studies have shown more and more correlations between these two diseases,and amylin oligomerization in the brain provided a novel risk target for developing AD.Although cumulative studies reported that amylin aggregation induced cytotoxicity in pancreatic beta cells by altering Ca2+homeostasis,fewer studies investigated the effect of amylin on hippocampal neuron.To address this question,it was investigated the effect of amylin on primary cultured rat hippocampal neurons by calcium imaging and whole-cell patch clamp recording in this study,while the results revealed that human amylin(hAmylin) but not rat amylin or pramlintide(hAmylin analgue) produced a rapid increase in intracellular calcium in a dose dependent manner.This effect relied on extracellular calcium and not abolished by amylin receptor antagonist AC187.Additionally,the calcium increase induced by hAmylin was dependent onvoltage-gated Ca2+channels,especially L-type Ca2+channel activation.In whole-cell recording hAmylin could depolarize membrane potential and increase the cell exitability.Moreover,application of transient receptor potential vanilloid(TRPV) antagonist ruthenium red could abolish part of the intracellular calcium increase.Single cell RT-PCR revealed that TRPV4 mRNA expressed in most of the reactive neuron and selective TRPV4 antagonist HC067047 inhibited the intacellular calcium increasing.These results indicated that hAmylin aggregation precipitating on the neuron membrane activated TRPV4 channels and then triggered membrane voltage gated calcium channel opening followed by membrane depolarization,expressing that TRPV4 is a key molecular target for the cytotoxic effect of hAmylin on cultured neurons.
文摘Objective:In the present study, the protein structure model of human amylin was generated to understand the protein's structure, function and mechanism of the action. Methods: The stereo chemical quality of the protein model was checked by usingin silico analysis withSWISSMODEL,SOPMA,PROCHECK, ProSA andQMEAN servers. Results:The 66.7% residues in the core region of Ramachandran plot showing high accuracy of protein model and the QMEAN Z score of –6.57 indicates the overall model quality of amylin protein. Conclusions: These results may be helpful for further investigation on developing target molecules for amylin proteins that play a key role in type 2 diabetes.
基金This work was supported by research grants from the National Natural Science Foundation of China(82070392 and 81900332).
文摘Co-secretion with insulin,highly amyloidogenic human amylin is considered to contribute to the initiation and progression of diabetic heart complications,despite other situations such as hypertension and atherosclerosis.In response to insulin resistance,hyperinsulinemia,and consequently hyperamylinemia,is common in prediabetic patients,where highly concentrated amylin is prone to form amylin oligomers,which further assemble into fibrils and amyloids with high b-sheet content.The infusion and deposition of oligomeric amylin in myocytes cause a series of consequences,including cytosolic Ca^(2+)dysregulation,calmodulin activation,myocyte hypertrophy,and ventricular stiffness,eventually leading to heart failure.In this review,we present the latest reports of amylin-related heart complications,provide new insights,and state the underlying pathogenesis,diagnosis,possible treatment,and prevention of diabetic cardiomyopathy.
文摘In the present study, we investigate effect of amylin on the insulin sensitivity of rat skeletal muscle extensor digitorum longus (EDL) using in vitro intact muscle incubation in combination with metabolic radioactive labeling. The molecular basis of the amylin action was further examined using proteomic analysis. In particular, proteins of interest were characterized using an integrated microcharacterization procedure that involved in-gel trypsin digestion, organic solvent extraction, high performance liquid chromatography separation, microsequencing and microsequence analysis. We found that amylin significantly decreased the insulin-stimulated glucose incorporation into glycogen (p < 0.01) and produced a protein spot of approximately 20 ku in size. This amylin responsive protein (hereby designated as amylin responsive protein 1, APR1) was identified to be protein p20. Moreover, ARP1 spots on gels were found to consistently produce a corresponding radioactive spot on X-ray films in 32Pi but not in 35S-methionine labeling experiments. In conclusion, our results showed that in vitro amylin concomitantly evoked the production of ARP1 and caused insulin resistance in EDL muscle. It is suggested that protein p20 may be involved in amylin signal transduction and the appearance of ARP1 may be a step in a molecular pathway leading to the development of insulin resistance. ARP1 might therefore be a useful molecular marker for amylin action, insulin resistance and Type 2 diabetes.
文摘目的探讨胰淀素(amylin)通过下丘脑室旁核(PVN)ERK通路对小鼠摄食行为的调控作用。方法将54只C57BL/6J小鼠随机分为多组开展实验。首先采用免疫荧光检测4只小鼠脑内ERK和降钙素受体(CTR)神经元的分布。通过化学损伤法建立PVN神经元损伤模型,将16只小鼠分为4组(每组4只):对照组(Ctrl)、鹅膏酸损毁组(IBO)、amylin组和amylin+IBO组,统计PVN区域ERK阳性神经元数量及摄食量。随后,将16只小鼠分为4组(每组4只):Ctrl组、amylin组、ERK拮抗剂U0126组、amylin+U0126组,通过Real-time PCR检测PVN即刻早期基因(c-fos)表达水平。免疫荧光检测Ctrl组和amylin组小鼠脑内p-ERK阳性神经元分布(每组4只)。最后,通过侧脑室注射,将18只小鼠随机分为3组(每组6只):Ctrl组、amylin组和amylin+受体拮抗剂AC187组,然后免疫荧光检测PVN区域p-ERK、神经型一氧化氮合酶(nNOS)及CTR免疫阳性神经元共表达,同步记录处理后3 h内的摄食量。结果ERK阳性神经元主要分布于视交叉上核(SCN)、弓状核(ARC)和蓝斑核(LC),而ERK和CTR共表达阳性神经元特异性富集于PVN(P<0.01)。PVN神经元损伤导致ERK阳性神经元数量减少(P<0.001),且阻断了amylin的抑食作用(P<0.001)。Amylin激活PVN区域c-fos基因表达(P<0.05),而该效应可被U0126抑制(P<0.05)。侧脑室注射amylin后,PVN中p-ERK、nNOS和CTR三标阳性神经元数量增加(P<0.05),添加AC187则阻断amylin的激活效应(P<0.01),并逆转amylin的抑食效应(1 h P=0.2218,2 h P=0.2218,3 h P=0.6974)。结论PVN中p-ERK神经元通过amylin受体依赖的ERK信号通路调控摄食行为。
