Identification and dipeptidyl peptidase Ⅳ(DPP-Ⅳ) inhibitory activity verification of peptides from mouse lymphocytes

The objective of this study was to isolate and identify the intracellular bioactive peptides from mouse lymphocytes before and after lipopolysaccharide(LPS)stimulation,to explore novel peptides and to research the bioactive function.Mouse spleen lymphocytes were isolated and cultured with LPS stimulation(experimental group)or not(control group)to collect intracellular peptides.Totally 385 peptides were analyzed by nanoliter liquid phase-Q Exactive quadrupole ultra-high resolution orbitrap mass spectrometer(Nano LC-Q Exactive Plus)and identifi ed by PEAKS X software.After compared with peptides reported,131 novel peptides were discovered,which then were predicted bioactivity by Peptide Ranker and 6 peptides with high bioactivity were predicted function by BIOPEP-UMW database.Prediction data showed that they may have dipeptidyl peptidase IV(DPP-IV)inhibitory activity.Finally,two peptides showed better potent inhibition were verifi ed with competitive and noncompetitive modes.

Dipeptidyl peptidase Ⅳ(DPP Ⅳ):a novel emerging target for thetreatment of type 2 diabetes

The enzyme, dipeptidyl peptidase IV（DPP IV）, is a novel target for the treatment of type 2 diabetes. Dipeptidyl peptidase IV inhibition improves the impaired insulin secretion and decrease postprandial concentrations of glucagon by enhancing the incretin hormone levels lucagon-like peptide-1（GLP-1） and glucose-dependent insulinotropic polypeptide/gastric inhibitory polypeptide（GIP）. Recently, DPP IV inhibitors have attracted more and more attention, several of which have entered pre-clinical and clinical trials, and one has received approval for use as an anti-diabetic agent. Among the DPP IV inhibitors, two leading agents（sitagliptin and vildagliptin） have been shown to be effective in reducing glycosylated hemoglobin（HbAlc） and fasting plasma glucose（FPG） in patients with type 2 diabetes. This review summarizes the evidence supporting DPP IV inhibitors as potential antidiabetic agents.

Effect of Urena lobataleaves extract on glucagon like peptide-1 serum level by inhibition of dipeptidyl peptidase-Ⅳ on diabetic rats

OBJECTIVE To investigate effect of Urenalobataleaves extract on glucagon like peptide-1(GLP-1)serum level by inhibition of dipeptidyl peptidase-Ⅳ(DPP-Ⅳ)on diabetic rat. METHODS This study uses control group post test only with male spraque dawley rats.Diabetic rats was induced by High Fructose Diet(HFD)and single dose streptozotocin 25mg·kg-1 bw intra peritoneal.The rat was administrated orally with ethanolic extract of U.lobataleaves in dose of 250,500 and 1000mg·kg-1 for 4weeks.Blood sample were collected from the tail vein at 15 min after oral glucose administration and then DPP-Ⅳserum level and GLP-1were examined using a rat elisa kits of DPP-Ⅳ and GLP-1.The data was analyzed using ANOVA test continued with LSD test(P<0.05).RESULTS The oral administration of U.lobataleaves extract at dose of 250,500 and 1000mg·kg-1 bw were able to prolong GLP-1 bioavaibility approximately 5,2and 2.5-fold respectively compared to diabetic group(P<0.05),while the DPP-Ⅳ serum level was decreased by 60%,50% and 40%(P<0.05),respectively.In diabetic groups,DPP-Ⅳ serum level was increased more and less 4-fold compared to normal group(P<0.05)while the GLP level were decreased by 8-fold(P<0.05).CONCLUSION U.lobataleaves extract could prolong GLP-1 bioavaibility by reducing of DPP-Ⅳserum level.This effect may be related to active compounds that act as an DPP-Ⅳinhibitor in U.lobata extract.

Dipeptidyl peptidase Ⅲ在先天性白内障大鼠晶状体中的免疫活性变化

目的 观察 8、10、12、14周龄正常及先天性白内障大鼠晶状体中dipeptidylpep tidaseⅢ (DPPⅢ )的免疫活性变化 ,探讨其与白内障发病的关系。方法 分别于 8、10、12、14周龄鼠 ,摘取正常对照组以及先天性白内障大鼠晶状体 ,应用抗生物素蛋白 生物素 过氧化物酶复合体法 ,观察不同时期大鼠晶状体中DPPⅢ的免疫活性变化。结果 各周龄先天性白内障大鼠晶状体纤维部DPPⅢ的免疫活性明显高于正常对照组 ,特别是 12、14周白内障晶状体中DPPⅢ的免疫阳性产物扩展至晶状体核周部。结论 DPPⅢ在白内障大鼠晶状体中免疫活性增强 ,它有可能在白内障形成过程中参与晶状体蛋白的水解分化 ,从而促进白内障的形成。

二肽基肽酶-Ⅳ有机小分子荧光探针的研究进展

二肽基肽酶-IV(DPP-IV)是一种重要的跨膜糖蛋白水解酶,与各种生理过程和疾病密切相关,检测DPP-IV的有机小分子荧光探针被相继报道,是当前研究生物酶检测的热点。首次综述了用于DPP-IV体外和体内检测及成像的3类有机小分子荧光探针,分别是非近红外荧光探针(λ_(em)<650nm)、近红外荧光探针(λ_(em)>650nm)和双光子荧光探针,对比并总结了三种探针的设计原理、结构特点、生物应用情况及其在DPP-IV相关疾病诊断中的应用,并探讨了DPP-IV活性检测在未来发展方向上所面临的挑战。

白果肽的二肽基肽酶-Ⅳ抑制活性及其抑制机理研究

食源性二肽基肽酶-Ⅳ(dipeptidyl peptidaseⅣ,DPP-Ⅳ)抑制肽可有效调节机体内糖代谢,降低机体血糖水平。为评估白果肽(phenylalanine-alanine-proline-serine-tryptophan,FAPSW和methionine-proline-glycine-proline-proline,MPGPP)的降糖潜能,采用体外试验测定其DPP-Ⅳ抑制活性,并进一步通过分子对接和分子动力学模拟揭示其抑制机理。结果表明,FAPSW和MPGPP具有良好的DPP-Ⅳ抑制活性,且MPGPP的DPP-Ⅳ抑制活性[IC_(50)=(0.158±0.009)g/L]强于FAPSW[IC_(50)=(2.540±0.126)g/L];分子对接结果表明,静电相互作用、氢键、疏水作用和范德华力在FAPSW和MPGPP抑制DPP-Ⅳ活性中起重要作用;分子动力学结果表明,FAPSW和MPGPP结合DPP-Ⅳ能形成稳定的复合物结构,且MPGPP-DPP-Ⅳ复合物的稳定性要强于FAPSW-DPP-Ⅳ。结合自由能结果表明,静电相互作用在FAPSW和MPGPP结合DPP-Ⅳ中起主导作用。研究结果可为FAPSW和MPGPP在功能食品领域的开发和利用提供一定的理论参考。

Anti-diabetic potential of Urena lobata leaf extract through inhibition of dipeptidyl peptidase IV activity

Objective: To evaluate the anti-diabetic potential of leaf extract from Urena lobata(U. lobata) through dipeptidyl peptidase IV(DPP-IV) inhibitory activity.Methods: U. lobata leaf was extracted in hot water and ethanol. The activity of DPPIV inhibitor was tested by in vitro study using gly-pro-p-nitroanilide as substrat of DPPIV and vildagliptin, as standard reference. A product of the reactions between gly-pro-pnitroanilide and DPP-IV, was observed by microplate readers with λ = 405 nm. All data were expressed as mean ± SD and the IC50 value was determined by non linear regression curve fit. Active substances in leaf extract of U. lobata was analyzed by liquid chromatography-mass spectrometry. DPP-IV inhibitory activity of active compounds was evaluated in silico using docking server. Results: The ethanolic extract of U. lobata showed stronger DPP-IV inhibitor activity than water extract with the IC50 values of 1 654.64 and 6 489.88 μg/mL, respectively. Vildagliptin, based on standard reference for DPP-IV inhibitor activity, has IC50 value of 57.44 μg/mL. Based on in silico analysis, mangiferin, stigmasterol and β-sitosterol in U. lobata extract have a strong inhibitory activity on DPP-IV. Conclusions: The results showed that DPP-IV inhibitory activity of U. lobata is related to its active compounds such as mangiferin, stigmasterol and β-sitosterol.

基于FAERS的二肽基肽酶-Ⅳ抑制剂皮肤不良事件信号挖掘与评价

目的为临床合理使用二肽基肽酶-Ⅳ(DPP-4)抑制剂提供参考。方法通过美国食品和药物管理局药品不良事件报告系统(FAERS)收集2010年至2021年各季度以全球已上市DPP-4抑制剂为首要怀疑药物的药品不良事件(ADE)报告,采用报告比值比(ROR)法挖掘DPP-4抑制剂的ADE信号,并利用《监管活动医学词典》(MedDRA)中的系统器官分类(SOC)提取并整理其中的皮肤ADE信号。结果以吉格列汀、奥格列汀、曲格列汀、安奈格列汀、依格列汀为首要怀疑药物的ADE报告数均为0份;以西格列汀、维格列汀、沙格列汀、阿格列汀、利格列汀、替格列汀为首要怀疑药物的ADE报告数分别为192131,2034,6787,3635,4532,2份,对应的皮肤ADE信号数依次为20,4,15,10,14,0个,且其中分别有18,2,7,9,8,0个ADE信号未在相应药品说明书中提及。在发生皮肤ADE的患者中,阿格列汀用药患者女性多于男性,其余4种药物反之;年龄多在65岁以上;维格列汀用药时长集中在0.5~1年,其余4种药物的用药时长集中在半年内或1年以上;西格列汀、维格列汀、沙格列汀、阿格列汀、利格列汀用药剂量依次集中在100,50,5,25,5 mg/d。使用西格列汀、阿格列汀的患者临床结局大多为住院,其余3种药物多为其他临床结局。结论DPP-4抑制剂可致多种皮肤ADE,临床用药时应密切监测。

Regulation of dipeptidyl peptidase 8 and 9 expression in activated lymphocytes and injured liver

AIM:To investigate the expression of dipeptidyl peptidase(DPP) 8 and DPP9 in lymphocytes and various models of liver fibrosis.METHODS:DPP8 and DPP9 expression were measured in mouse splenic CD4 + T-cells,CD8 + T-cells and B-cells(B220 +),human lymphoma cell lines and mouse splenocytes stimulated with pokeweed mitogen(PWM) or lipopolysaccharide(LPS),and in dithiothreitol(DTT) and mitomycin-C treated Raji cells.DPP8 and DPP9 expression were measured in epidermal growth factor(EGF) treated Huh7 hepatoma cells,in fibrotic liver samples from mice treated with carbon tetrachloride(CCl 4) and from multidrug resistance gene 2(Mdr2 /Abcb4) gene knockout(gko) mice with biliary fibrosis,and in human end stage primary biliary cirrhosis(PBC).RESULTS:All three lymphocyte subsets expressed DPP8 and DPP9 mRNA.DPP8 and DPP9 expression were upregulated in both PWM and LPS stimulated mouse splenocytes and in both Jurkat T-and Raji B-cell lines.DPP8 and DPP9 were downregulated in DTT treated and upregulated in mitomycin-C treated Raji cells.DPP9transfected Raji cells exhibited more annexin V + cells and associated apoptosis.DPP8 and DPP9 mRNA were upregulated in CCl 4 induced fibrotic livers but not in the lymphocytes isolated from such livers,while DPP9 was upregulated in EGF stimulated Huh7 cells.In contrast,intrahepatic DPP8 and DPP9 mRNA expression levels were low in the Mdr2 gko mouse and in human PBC compared to non-diseased livers.CONCLUSION:These expression patterns point to biological roles for DPP8 and DPP9 in lymphocyte activation and apoptosis and in hepatocytes during liver disease pathogenesis.

Role of dipeptidyl peptidase 4 inhibitors in the new era of antidiabetic treatment

The last few years important changes have occurred in the field of diabetes treatment.The priority in the therapy of patients with diabetes is not glycemic control per se rather an overall management of risk factors,while individualization of glycemic target is suggested.Furthermore,regulatory authorities now require evidence of cardiovascular(CV)safety in order to approve new antidiabetic agents.The most novel drug classes,i.e.,sodium-glucose transporter 2 inhibitors(SGLT2-i)and some glucagon-like peptide-1 receptor agonists(GLP-1 RA),have been demonstrated to reduce major adverse CV events and,thus,have a prominent position in the therapeutic algorithm of hyperglycemia.In this context,the role of previously used hypoglycemic agents,including dipeptidyl peptidase 4(DPP-4)inhibitors,has been modified.DPP-4 inhibitors have a favorable safety profile,do not cause hypoglycemia or weight gain and do not require dose uptitration.Furthermore,they can be administered in patients with chronic kidney disease after dose modification and elderly patients with diabetes.Still,though,they have been undermined to a third line therapeutic choice as they have not been shown to reduce CV events as is the case with SGLT2-i and GLP-1 RA.Overall,DPP-4 inhibitors appear to have a place in the management of patients with diabetes as a safe class of oral glucose lowering agents with great experience in their use.

Dipeptidyl peptidase-4 inhibitor for steroid-induced diabetes

The addition of the dipeptidyl peptidase-4 (DDP-4) inhibitor has been reported to achieve greater improvements in glucose metabolism with fewer adverse events compared to increasing the metformin dose in type 2 diabetic patients. We present a patient with steroid-induced diabetes whose blood glucose levels were ameliorated by the use of the DPP-4 inhibitor, showing that the DPP-4 inhibitors may be an effective and safe oral anti-diabetic drug for steroid-induced diabetes.

芦笋水提物的不同膜分离部位对二肽基肽酶-Ⅳ活性的影响及其成分分析

为明确芦笋水提物中抑制二肽基肽酶-Ⅳ(Dipeptidyl peptidase-4,DPP-4)活性的主要功能成分,本文通过膜分离技术,制备了五种截留分子量不同的芦笋水提物部位,包括>30、10~30、6~10、3~6和<3 kDa,并对各部位进行了DPP-4抑制效果比较,对其总皂苷、总黄酮、总多糖、总多酚、总氮含量进行了比较分析。结果显示,总氮含量与抑制率呈最高正相关性(P<0.01),截留分子量大于30 kDa(UAJ1)是总氮含量最高的部位并表现出最强的抑制作用,其IC_(50)值为8.19 mg/mL,属于混合型抑制类型。总多糖含量与抑制率呈极显著正相关性,但次之(P<0.01)。总多酚含量与抑制率也呈显著的正相关性(P<0.05),而总黄酮含量与抑制率呈极显著负相关性(P<0.01)。总皂苷与抑制率之间无显著相关性。综合以上结果,芦笋水提物中对DPP-4起主要抑制作用的组分为分子量大于30 kDa的蛋白组分。这一发现可为天然DPP-4抑制剂在降血糖保健食品及药物开发提供参考。

Low expression of angiotensinogen and dipeptidyl peptidase 1 in saliva of patients with proliferative verrucous leukoplakia

AIM To elucidate the profile of the salivary proteome.METHODS Unstimulated whole mouth saliva was collected from 30 volunteers [15 proliferative verrucous leukoplakia(PVL) patients and 15 controls] and proteins were submitted for mass spectrometry-based proteomics using the discovery approach,followed by analyses of variance and logistic regression tests.RESULTS A total of two hundred and eighty-three proteins were confidently identified in saliva.By combining two low abundance proteins from the PVL group,angiotensinogen(AGT) and dipeptidyl peptidase 1(DPP1),a model for group differentiation was built with a concordance index of 94.2%,identifying both proteins as potential etiologic biomarkers for PVL.CONCLUSION This study suggests that both AGT and DPP1 may be involved in developmental mechanisms of PVL.

Accurate Assessment and Tracking the Process of Liver-Specific Injury by the Residual Tissue Activity of Carboxylesterase 1 and Dipeptidyl Peptidase 4

Accurately assessing and tracking the progression of liver-specific injury remains a major challenge in the field of biomarker research.Here,we took a retrospective validation approach built on the mutuality between serum and tissue biomarkers to characterize the liver-specific damage of bile duct cells caused by a-naphthyl isothiocyanate(ANIT).We found that carboxylesterase 1(CES1),as an intrahepatic marker,and dipeptidyl peptidase 4(DPP-IV),as an extrahepatic marker,can reflect the different pathophysiologies of liver injury.Levels of CES1 and DPP-IV can be used to identify liver damage itself and the inflammatory state,respectively.While the levels of the conventional serological biomarkers alkaline phosphatase(ALP),alanine aminotransferase(ALT),and aspartate aminotransferase(AST)were all concomitantly elevated in serum and tissues after ANIT-induced injury,the levels of bile acids decreased in bile,increased in serum,and ascended in intrahepatic tissue.Although the level of γ-glutamyl transpeptidase(γ-GT)changed in an opposite direction,the duration was much shorter than that of CES1 and was quickly restored to normal levels.Therefore,among the abovementioned biomarkers,only CES1 made it possible to specifically determine whether the liver cells were destroyed or damaged without interference from inflammation.CES1 also enabled accurate assessment of the anti-cholestasis effects of ursodeoxycholic acid(UDCA;single component)and Qing Fei Pai Du Decoction(QFPDD;multicomponent).We found that both QFPDD and UDCA attenuated ANIT-induced liver damage.UDCA was more potent in promoting bile excretion but showed relatively weaker anti-injury and antiinflammatory effects than QFPDD,whereas QFPDD was more effective in blocking liver inflammation and repairing liver damage.Our data highlights the potential of the combined use of CES1(as an intrahepatic marker of liver damage)and DPP-IV(as an extrahepatic marker of inflammation)for the accurate evaluation and tracking of liver-specific injury—an application that allows for the differentiation of liver damage and inflammatory liver injury.

Neonatal Exposure to the Dipeptidyl Peptidase-IV Inhibitors Diprotin A and Sitagliptin Induces Depression-Like Behavior, Anxiety, and Latent Aggression in Adolescent and Adult Rats

Emotional and motivational disorders in adults are often considered to be the result of altered neurodevelopment. Clinical and experimental data provide evidence that serine protease dipeptidyl peptidase-IV (DPP-IV, EC 3.4.14.5) is involved in the pathophysiology of psycho-emotional disorders. Recently, we have shown that adolescent and adult rats exhibit an increase in anxiety and depression-related behaviors after neonatal administration of a synthetic non-competitive inhibitor of DPP-IV, methionyl-2(S)-cyano-pyrrolidine. In the present study, we tested the effects of two competitive, selective DPP-IV inhibitors, sitagliptin (4 mg/kg) and diprotin A (2 mg/kg), administered at postnatal days 5 - 18 on the emotional and motivational behavior of adolescent and adult rats. We observed increased anxiety in one-month-old diprotin A- or sitagliptin-treated rats in the elevated plus maze;diprotin A also enhanced the animals’ anxiety score using a ranked scale for evaluating anxiety and phobias. In the sucrose consumption and preference test, depressive-like behavior was pronounced in both the diprotin A- and sitagliptin-treated one-month-old animals, while only the diprotin A-treated rats exhibited a decrease in sucrose consumption at the age of 2 months. The diprotin A-treated rats also demonstrated behavioral despair and decreased activity in the forced swimming test within 1 - 3 months of age. Increased aggression was observed in 1 - 3-month-old diprotin A-treated rats and in two-month-old sitagliptin-treated rats. These findings support the hypothesis that DPP-IV is involved in the genesis of emotional and motivational disorders. Additionally, the results show that diprotin А impairs the adolescent and adult rats’ behavior more significantly than sitagliptin when the animals were treated with the DPP-IV inhibitors in the early postnatal period.

Review on the Effect of Glucagon-Like Peptide-1 Receptor Agonists and Dipeptidyl Peptidase-4 Inhibitors for the Treatment of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease（NAFLD） is a common liver disease and it represents the hepatic manifestation of metabolic syndrome, which includes type 2 diabetes mellitus（T2DM）, dyslipidemia, central obesity and hypertension. Glucagon-like peptide-1（GLP-1） analogues and dipeptidyl peptidase-4（DPP-4） inhibitors were widely used to treat T2 DM. These agents improve glycemic control, promote weight loss and improve lipid metabolism. Recent studies have demonstrated that the GLP-1 receptor（GLP-1R） is present and functional in human and rat hepatocytes. In this review, we present data from animal researches and human clinical studies that showed GLP-1 analogues and DPP-4 inhibitors can decrease hepatic triglyceride（TG） content and improve hepatic steatosis, although some effects could be a result of improvements in metabolic parameters. Multiple hepatocyte signal transduction pathways and m RNA from key enzymes in fatty acid metabolism appear to be activated by GLP-1 and its analogues. Thus, the data support the need for more rigorous prospective clinical trials to further investigate the potential of incretin therapies to treat patients with NAFLD.

Risk of pancreatic adverse events associated with the use of glucagon-like peptide-1 receptor agonist and dipeptidyl peptidase-4 inhibitor drugs: A systematic review and metaanalysis of randomized trials

AIM: To systematically assess risk of pancreatic adverse events with glucagon-like peptide-1(GLP-1) receptor agonist and dipeptidyl peptidase-4(DPP-4) inhibitor drugs.METHODS: We searched Pub Med, Embase, CINAHL, Cochrane review of clinical trials, pharmaceutical company clinical trials register, United States Food and Drug Administration website, European Medicines Agency website and Clinical Trials.gov for randomized controlled trials from inception to October 2013. Randomized control trial studies were selected for inclusion if they reported on pancreatic complication events and/or changes in pancreatic enzyme levels(serum amylase and serum lipase) as adverse events or as serious adverse events for patients who were on GLP-1 receptor agonist and DPP-4 inhibitor drugs. Two independent reviewers extracted data directly. We performed Peto odds ratio(OR) fixed effect meta-analysis of pancreatic adverse events a, and assessed heterogeneity with the I^2 statistic.RESULTS: Sixty-eight randomized controlled trials were eligible. A total of 60720 patients were included in our analysis of the association of risk of pancreatic complication events with GLP-1 agents. A total of 89 pancreatic related adverse events occurred among the GLP-1 agents compared to 74 events among the controls. There was a statistically significant increased risk of elevation of pancreatic enzymes associated with GLP-1 agents compared with control(Peto OR = 3.15, 95%CI: 1.56-6.39, P = 0.001, I2 = 0%). There was no statistically significant difference in the risk of pancreatic adverse event associated with GLP-1 agent compared with controls(Peto OR = 1.00, 95%CI: 0.73-1.37, P = 1.00, I2 = 0%). There were a total of 71 pancreatitis events in patients on GLP-1 agents and 56 pancreatitis events occurred in the control patients. There were 36 reports of pancreatic cancer in these studies. Of these cases, 2 used linagliptin, 2 used alogliptin, 1 used vildagliptin, 7 used saxagliptin while 6 used sitagliptin. The remaining 18 cases occurred among controls.CONCLUSION: Although GLP-1 based agents are associated with pancreatic enzyme elevation, we were unable to confirm a significant risk of pancreatitis or pancreatic cancer.

Expression of a novel dipeptidyl peptidase 8(DPP8)transcript variant,DPP8-v3,in human testis

Aim： To investigate the role of a novel dipeptidyl peptidase 8 transcript variant （DPP8-v3） gene in testis development and/or spermatogenesis. Methods： A human testis cDNA microarray was hybridized with mRNA of human adult and fetal testes. Differentially expressed clones were sequenced and characterized and their expression was analyzed by real-time reverse transcription polymerase chain reaction （RT-PCR） and Southern-blot analysis. Results： A new transcript variant of the human dipeptidyl peptidase （DPP8）, exhibiting a 5-fold higher expression level in human adult than that in fetal testes, was cloned and was named DPP8 variant 3 （DPP8-v3）. The full-length sequence of DPP8-v3 was 3,030 bp, encoding a protein of 898 amino acids. Conclusion： DPPS-v3 is a novel human DPP8 transcript variant highly expressed in the adult testis. Similar to DPPIV, DPP8-v3 may play a key role in the immunoregulation of testes and accordingly may influence spermatogenesis and male fertility. （Asian J Androl 2005 Sep; 7： 245-255）

Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of E3024, a Novel and Selective Dipeptidyl Peptidase-IV Inhibitor, in Healthy Japanese Male Subjects: Rash Development in Men and Its Possible Mechanism

E3024 (3-but-2-ynyl-5-methyl-2-piperazin-1-yl-3,5-dihydro-4H-imidazo[4,5-d]pyridazin-4-one tosylate) is a dipeptidyl peptidase-IV (DPP-IV) inhibitor that was expected to be an antidiabetic agent. Its safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) were investigated in a randomized, double-blind, placebo-controlled, ascending single-dose study in 48 healthy Japanese male subjects. Fasted subjects were orally administered E3024 (5, 10, 20, 40, or 80 mg) or placebo. E3024 was rapidly absorbed, with tmax values ranging between 0.33 and 3 h after dosing. The mean t1/2 ranged from 5.34 to 11.68 h. AUC0-inf and Cmax increased dose-proportionately. PK-PD relationship of E3024 was evaluated by using an Imax model, indicating that plasma E3024 concentrations and inhibitory effects of plasma DPP-IV activity were well correlated. The IC50 value was calculated as 33.7 ng/mL, which was consistent with in vitro data. Thus, E3024 showed a good PK profile and inhibited DPP-IV dose-dependently. Of 30 subjects administered E3024, 12 (40%) experienced adverse events (AEs). Dose escalation to 160 mg was abandoned owing to undesired subjective/objective findings in 4 of 6 subjects receiving 40 mg and 5 of 6 subjects receiving 80 mg. The most prominent AE was rash, but there were no serious AEs or deaths. The maximum tolerated dose was considered to be 20 mg. We hypothesized that histamine was a cause of the rash induction, and examined blood histamine levels of normal Fischer rats treated with E3024. Blood histamine levels were increased significantly by E3024 at 500 mg/kg (p < 0.001), but not by vildagliptin or valine-pyrrolidide (DPP-IV inhibitors) at the same dose. No blood histamine increases were observed in genetically mast cell-deficient Ws/Ws rats treated with E3024 at 500 mg/kg. In in vitro assays, E3024 induced histamine release from normal rat peritoneal mast cells in a concentration-dependent manner, but not from basophils. The structure-activity relationship study suggested that a piperazine group N-linked to the 2-position of the 5,6-membered fused heterocyclic rings was a key structural element for triggering histamine release.

芹菜素对二肽基肽酶Ⅳ的抑制作用及其机制

目的:探究芹菜素降血糖作用的机制。方法:考察不同浓度的芹菜素对糖尿病治疗靶点二肽基肽酶Ⅳ(dipeptidyl peptidase-4,DPP-4)的抑制活性,并进一步利用酶动力学、荧光光谱、分子对接等实验手段明确了芹菜素对DPP-4的抑制类型以及作用机制。结果:芹菜素对DPP-4具有可逆的非竞争性抑制作用,其半数抑制浓度为(62.45±1.22)μg/mL;芹菜素主要通过氢键和范德华力作用与DPP-4形成基态复合物,造成DPP-4内在荧光的猝灭;芹菜素可与DPP-4分子中VAL-207、ARG-358、TYR-662残基形成较强的氢键,并与周围众多的疏水残基存在疏水作用,共同维持该复合物的结构。结论:本试验结果可为芹菜及芹菜素类降血糖产品的开发提供科学依据。