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Aim To explore the effects of putative receptor protein related to ATI (APJ) homodimer on the behaviors-the proliferation, migration and tube formation of human umbilical vein endothelial cells (HU-VECs). Methods HUVECs at logarithmic growth stage were randomly divided into PBS, Apelin-13 + TM1 (APJ monomer group) and Apelin-13 + PBS group (APJ homodimer group). Western blot and Matrix-Assisted Laser Desorption/Ionization Time of Fligh Mass Spectrometry (MALDI-TOF MS) were used to detect the expression of APJ and APJ homodimer in HUVECs, respectively. Real-Time Cell Analyzers (RT-CA) was used to detect the concentration of the maximum effect of Apelin-13. Cell viability was detected by CCK-8. The cell migration ability was detected by scratch test, and the number of tubes formed on matri-gel that made artificial basement membrane was counted. Results Western blot and MALDI-TOF MS showed that APJ and APJ homodimer were expressed in HUVECs. The EC50 of Apelin-13 was 2.26 x 10
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ABSTRACT Objective: This study investigated whether ELABELA plays a role in the differential diagnosis of benign and malignant lesions of the thyroid gland. Subjects and methods: Of the 87 patients included in the study, 12 had undergone surgery for benign thyroid diseases, 30 had papillary thyroid cancer without invasion and/or lymph node metastasis in the surrounding tissues in the pathology report, and 45 had papillary thyroid cancer with invasion and/or lymph node metastasis in the surrounding tissues. Results: In the macrocarcinoma group, the proportion of patients with severe ELABELA staining (61.1%) was higher than that in the adenoma (50%) and microcarcinoma (23.8%) groups, while the proportion of those with mild to moderate staining was lower (p < 0.001). In the microcarcinoma group, the proportion of patients with severe staining was lower than that in the adenoma group, while the proportion of those with mild to moderate staining was higher (p < 0.001). In papillary thyroid carcinomas, the rates of moderate and severe staining in the classical variant, mild staining in the follicular variant, severe staining in the classical + follicular variant, and severe staining in the oncocytic variant were higher. Conclusion: To the best of our knowledge, this study is the first to be conducted on this subject. In this study, ELABELA was not found to be significant in the differential diagnosis of benign and malignant lesions of the thyroid gland. In papillary thyroid carcinomas, severe ELABELA staining patterns were more common in macrocarcinoma patients than in microcarcinoma patients.
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Humans , Thyroid Neoplasms/diagnosis , Carcinoma, Papillary/diagnosis , Diagnosis, Differential , Thyroid Cancer, Papillary/diagnosisABSTRACT
Elabelas/Toddlers belong to a group of endogenous active peptides recently discovered from zebrafish. The sequences of these peptides have 25% homology to Apelin. These peptides regulate physiological functions of organisms through putative protein receptors related to the angiotensin receptor AT1 (APJ). Functional roles of Elabela include early embryonic development, angiogenesis, fluid homeostasis, and feeding or dietary behavior control. Elabela also participates in the development of many diseases, such as heart failure, preeclampsia, acute kidney injury, hypertension, and diabetes. Increasingly, studies have shown that Elabela/APJ signaling can promote normal development of early embryos, including differentiation of mesoderm and endoderm, and formation of cardiac morphology and function. At the same time, the signaling can also promote angiogenesis or migration and proliferation of tumor cells. Here we describe the molecular structure, biological characteristics, functions and application prospects of Elabela/APJ signaling.
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This study was aimed to observe the effect of Si-Miao Yong-An (SMYA) decoction intervention in atherosclerosis (AS) vulnerable plaque,and to further explore the action mechanism from the entry point of vasa vasorum (VV) neovascularization.Male ApoE-/-mice were randomly divided into the model group,simvastatin group and SMYA group.High-fat diet added 1.1％ L-methionine was fed for 8 weeks to establish the AS vulnerable plaque model.The C57BL/6 mice were used as control.After 8 weeks' continuous medication,mice were sacrificed.HE staining were used to observe the pathological changes of mice aorta;immunohistochemical staining was used to observe the VV density in AS plaque and aortic adventitia;macrophage infiltration in plaque was also detected;the blood-lipid changes of TC,TG,LDL-C and HDL-C were detected;western blot was used to detect essential proteins of HIF-1α-Apelin/APJ signal pathway.The results showed that SMYA decoction decreased the plaque area and the ratio of plaque area and lumen area,increased the minimum thickness of fibrous cap,which significantly improved the pathological feature of aortic plaque in mice.The function of increasing the minimum thickness of fibrous cap was obviously superior to simvastatin.SMYA decoction effectively suppressed the VV neovascularization and decreased the macrophage content.SMYA decoction effectively decreased the serum level of TC,TG and LDL-C;however,it had no effect on HDL-C.SMYA decoction decreased the protein expression of HIF-1α.Its function was obviously superior to simvastatin.SMYA decoction can down-regulate the protein expressions of Apelin,APJ,Phospho-MEK1/2 (Ser217/221),Phospho-p44/42 MAPK (Erk1/2) (Thr202/Tyr204) and Phospho-p70 S6 Kinase (Thr421/Ser424).It was concluded that SMYA decoction regulated the HIF-1α-Apelin/APJ signal pathway,suppressed VV neovascularization and stabilized AS vulnerable plaque.
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The G protein-coupled receptor was deorphanized with cloning of the APJ-endogenous ligand apelin,which is an important active peptides.Apelin/APJ system is widely distributed in central nervous system,cardiovascular system,immune system and endocrine system.Therefore,apelin plays important physiological and pathological roles in blood pressure regulation,fluid homeostasis,potent inotropic,insulin sensitivity regulation,pituitary hormone release,human immunodeficiency virus (HIV) entry inhibition,etc.Recently,the studies found apelin/APJ system also regulates the vasculogenesis and angiogenesis of retina through inducing cell proliferation,migration and tube formation in endothelium.The experiments in vivo also demonstrate apelin/APJ system plays a role in physiological and pathological retinal vascular formation.This review summarizes the evidence of apelin in physiological retinal vascular diseases and diabetic retinopathy,retinopathy of prematurity and choroidal neovascular ization.
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Objective To observe the effects of simplified recipe ofBuyang Huanwu Decoction on expression of APJ in the brain of local cerebral ischemia rats;To discuss its mechanism of action. MethodsFocal cerebral ischemia rat models were established by middle cerebral arterial occlusion. The adult rats were randomly divided into sham-operation group, model group,Buyang Huanwu Decoction group and simplified recipe ofBuyang Huanwu Decoction group. Administration groups were given relevant medicine for gavage. The expressions of APJ protein and APJ mRNA at different time points were detected by Western blot and RT-PCR.ResultsCompared with model group and sham-operation group, the expression of APJ protein and APJ mRNA at different time points in Buyang Huanwu Decoction group and simplified recipe ofBuyang Huanwu Decoction group significantly increased (P<0.05). The expression of APJ protein at different time points showed no difference between simplified recipe ofBuyang Huanwu Decoction group andBuyang Huanwu Decoction group;while the expression of APJ mRNA in simplified recipe ofBuyang Huanwu Decoction group was higher than Buyang Huanwu Decoction group (P<0.05).ConclusionSimplified recipe ofBuyang Huanwu Decoction plays a role in neural protection and restoration by promoting the expression of APJ in the brain of focal cerebral ischemia rats.
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Aim To observe the effect of high salt stress on sympathetic nerve activity and brain Apelin and APJ system in pressure overload rats.Methods The suprarenal abdominal aorta was banded in male SD rats to create the pressure overload model.Four weeks later,the rats were fed a high-salt (8%NaCl)diet or a regular-salt (0.3% NaCl)diet for 1 week,and the hemodynamic changes of the rats were recorded.Sym-pathetic activity was evaluated by measuring 24 h uri-nary norepinephrine (NE)by ELISA.Real-time RCR and Western blot method were used to analyze the Ape-lin and APJ expression in the paraventricular nucleus of rats.In another protocol,ML22 1 or benzamil was intracerebroventricularly infused in the aorta banding rats fed with high-salt,and levels of 24 h urinary NE and cardiac index were recorded.In addition,normal SD rats were intracerebroventricularly infused with Na+-rich aCSF for 1 week,and the changes of blood pressure,24 h urine-NE and APJ expression levels were detected.Results In the pressure overload rats fed with high salt diet for 1 week,the mean arterial blood pressure (MAP),heart rate (HR),left ventric-ular end systolic pressure (LVESP),24 h urinary NE and APJ mRNA protein expression in paraventricular nuclear were significantly increased compared with those in control groups (P<0.05 ).However,the he-modynamics,24 h urinary NE and APJ expression showed no significant change in the sham rats fed a high salt diet.In addition,ICV infusion of APJ recep-tor antagonist ML221 or the ENaC antagonist benzamil significantly inhibited the 24 h urinary NE level and HW/BW ratio in the pressure overload rats fed high salt diet (P <0.01 ).Intracerebroventricular infusion of high Na+aCSF for 1 week in normotensive rats also significantly increased the MAP,HR,urinary-NE lev-els and brain APJ expression (P <0.0 1 ).Conclu-sions High salt increases the sympathetic nerve activ-ity in rats with pressure overload model, which is closely related to the brain APJ receptor expression and Na+sensitivity.Brain APJ receptor may be an impor-tant target in the development of salt sensitivity.
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Aim To explore the changes of Apelin/APJ system in LPS-induced injury of rat pulmonary mi-crovascular endothelial cells( PMVECs) , and the effect and mechanism of Apelin. Methods PMVECs were cultured with the explant technique, and the identifica-tion of rat PMVECs was carried out by immunocyto-chemical staining of factorⅧrelated antigen. MTT as-say was used to evaluate the viability of PMVECs. The mRNA expression of Apelin and APJ was detected by RT-PCR. The protein expression of PCNA and the phosphorylation of Akt was analyzed by Western blot. Results The mRNA expression of Apelin and APJ showed a compensatory increase after LPS treatment for a short period of time ( P<0. 01 ) , but with the exten-sion of time, which was significantly inhibited, even lower than the control group ( P<0. 05 or P<0. 01 ) , suggesting that Apelin/ APJ system might be involved in LPS-induced PMVECs injury. MTT results showed that 10 -6 ~10 -9 mol · L-1 Apelin obviously promoted the proliferation of rat PMVECs ( P <0. 05 or P <0. 01 ) , and with certain concentration and time de-pendence. Moreover, Apelin also improved the LPS-induced PMVECs injury in different degrees ( P<0. 05 or P < 0. 01 ) . In addition, Western blot analysis showed that Apelin significantly reversed the decrease of the protein expression of PCNA and the Akt phos-phorylation level induced by LPS ( P <0. 05 or P <0. 01 ) . Conclusions The Apelin/APJ system is in-volved in LPS-induced PMVECs injury. Apelin plays an important role in protecting the pulmonary microvas-cular endothelial function and reversing the LPS-in-duced PMVECs injury, which might be related to the activation of Akt phosphorylation pathway.
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Objective To detect the expression of apelin and angiotensin I receptor related protein (APJ) in rats with chronic obstructive pulmonary disease (COPD), and to explore the role of apelin-APJ system in the occurrence and development of COPD. Methods A rat model of COPD was established using the method of smoke exposure. SD rats were randomly divided into a control group and a COPD group. The rats in COPD group were exposed to secondhand cigarette smoke in a fume box twice a day for 4 months. Expressions of apelin mRNA and APJ mRNA in rat lung tissues were detected by real-time quantitative polymerase chain reaction (qRT-PCR). Expressions of apelin protein and APJ protein were determined by immunohistochemistry. Results The expressions of apelin mRNA and APJ mRNA in COPD group were decreased by 44% and 13% as compared with those in the control group. The mRNA expressions of apelin and APJ in rat lung tissues were negatively correlated with RV/(LV + S) (r = -0.454 and -0.448, P < 0.05), and positively related with FEV0.3/FVC (r = 0.529 and 0.475;P < 0.05). Apelin and APJ were mainly expressed in the epithelial cells of the bronch and lung, alveolar macrophages, vascular endothelial cells, and the membrane and cytoplasm of some alveolar wall cells. The expression of apelin and APJ protein was lower in COPD group than in the control group (P < 0.05). Conclusions The mRNA and protein expressions of apelin and APJ are decreased in the lung tissues in rats with COPD , which may be an important factor leading to the development of COPD. Apelin-APJ system might be a new target for prevention and treatment of pulmonary hypertension and right ventricular hypertrophy induced by COPD.
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The family of apelin peptides is derived from a single gene and activates the 7-transmembrane G-protein-coupled receptor,namely APJ.Apelins have been shown to be involved in the regulation of cardiovascular functions,fluid homeostasis,central nervous system functions,insulin sensitivity,food and water intake.The properties of this system may make it a novel drug target of therapeutic applications in the cardiovascular diseases such as hypertension and heart failure,and related diseases like obesity.
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Objective To investigate whether the effect of puerarin on right ventricle hypertrophy of pulmonary hypertensive rats induced by chronic hypoxia-hypercapnia was related to new peptide Apelin or its receptor(APJ).Methods Thirty male Sprague-Dawley rats were randomly divided into three groups, they are control group,hypoxia-hypercapnia 4-week model group,and hypoxia-hypercapnia 4-week plus puerarin group.The concentrations of Apelin-36 protein in plasma and homogenate of right ventricular muscle were detected by radioimmunoassay.The mRNA expressions of Apelin and APJ in right ventricu- lar muscle were measured by semi-quantitive reverse transcription polymerase chain reaction(RT-PCR). Results The weight ratio of right ventricle to left ventricle plus septum[RV/(LV+S)] in model group was significantly higher than that in control group(P0.05).The plasma concen- tration of Apelin-36 protein in model group was significantly higher than that in control group(P
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Objective To observe apelin and its receptor (APJ) expressions in human osteoblasts and evaluate the effect of apelin on osteoblasts.Methods The expressions of apelin and APJ in human osteoblasts were tested by RT-PCR and Western blot.After human osteoblasts were treated with apelin,cell proliferation was measured by [~3H] thymidine incorporation and cell counting.Cell function was measured by alkaline phosphatase (ALP) activity,the secreted osteocalcin level and typeⅠcollagen production .The activation of signaling cascades was tested by Western blot.Small-interfering RNA (siRNA) to blockade APJ was applied to observe effects of apelin on cell proliferation and the activation of signaling cascades.Results Both apelin and APJ were expressed in human osteoblasts.Apelin increased the proliferation and did not show the influences on ALP activity, osteocalcin secretion and type I collagen production in human osteoblasts.Apelin induced activation of phosphatidylinositol-3 kinase (PI3K) downstream effector (Akt),but not mitogen-activated protein kinase (MAPK) such as c-jun N-terminal kinase (JNK),p38 and ERK1/2 in human osteoblasts.Suppression of APJ with siRNA or LY294002 (PI3K inhibitor) abolished the apelin-induced cell proliferation and the activation of Akt.Conclusion Human osteoblasts express apelin and APJ.Apelin stimulates the proliferation of human osteoblast via APJ/PI3K/Akt pathway,but has no effect on osteoblast differentiation.