Micropeptides: origins, identification, and potential role in metabolism-related diseases. / å¾®è‚½ï¼šèµ·æºã€é‰´å®šåŠå ¶åœ¨ä»£è°¢ç›¸å ³ç–¾ç— ä¸­çš„ä½œç”¨.

With the development of modern sequencing techniques and bioinformatics, genomes that were once thought to be noncoding have been found to encode abundant functional micropeptides (miPs), a kind of small polypeptides. Although miPs are difficult to analyze and identify, a number of studies have begun to focus on them. More and more miPs have been revealed as essential for energy metabolism homeostasis, immune regulation, and tumor growth and development. Many reports have shown that miPs are especially essential for regulating glucose and lipid metabolism and regulating mitochondrial function. MiPs are also involved in the progression of related diseases. This paper reviews the sources and identification of miPs, as well as the functional significance of miPs for metabolism-related diseases, with the aim of revealing their potential clinical applications.

Exosomal circ-1199 derived from EPCs exposed to oscillating shear stress acts as a sponge of let-7g-5p to promote endothelial-mesenchymal transition of EPCs by increasing HMGA2 expression.

AIMS: Our previous study showed that oscillatory shear stress (OSS) induces endothelial progenitor cells (EPCs) to undergo endothelial to mesenchymal transition (EndoMT), which may contribute to the onset and progression of atherosclerosis (AS). However, the underlying mechanisms have not been elucidated. A recent study showed that exosomes (Exos) released from EPCs played a key role in various cardiovascular diseases. The purpose of this study was to identify the role and mechanism of Exos released by EPCs exposed to OSS in EPC EndoMT. MAIN METHODS: EPCs derived from the human umbilical cord blood were cultured and characterized. The Flexcell flow STR-4000 parallel plate flow chamber system was employed to apply OSS (±3.5 dyne/cm2, 1 Hz) to EPCs for 12 h. Then, Exos were extracted from the cellular supernatant (Static-Exos) or perfusate (OSS-Exos) by exoEasy Maxi Kit. Afterward, cellular intervention, angiogenesis assays, high-throughput sequencing and online database predictions were used to identify the role and mechanism of OSS-Exos in EPC EndoMT. KEY FINDINGS: OSS-Exos inhibited angiogenesis, promoted the proliferation of EPCs both in vivo and in vitro, and induced EPC EndoMT. In addition, the expression of circ-1199 in OSS-Exos was higher than that in Static-Exos. Moreover, circ-1199 induced EPC EndoMT. The dual-luciferase reporter gene assay showed that let-7g-5p was the direct target of circ-1199. Furthermore, OSS-Exos upregulated the expression of circ-1199 and then downregulated let-7g-5p, upregulating HMGA2, which activated p-Smad3/Smad3 and Snail. SIGNIFICANCE: OSS-Exos played an important role in the EndoMT of EPCs, which was mediated by the circ-1199/let-7g-5p/HMGA2 signaling pathway. These studies would have a high probability of revealing the mechanism of EPC EndoMT.

Advancements in the Regulation of Different-Intensity Exercise Interventions on Arterial Endothelial Function.

Normal-functioning endothelium is crucial to maintaining vascular homeostasis and inhibiting the development and progression of cardiovascular diseases such as atherosclerosis. Exercise training has been proven effective in regulating arterial endothelial function, and the effect of this regulation is closely related to exercise intensity and the status of arterial endothelial function. With this review, we investigated the effects of the exercise of different intensity on the function of arterial endothelium and the underlying molecular biological mechanisms. Existing studies indicate that low-intensity exercise improves arterial endothelial function in individuals who manifest endothelial dysfunction relative to those with normal endothelial function. Most moderate-intensity exercise promotes endothelial function in individuals with both normal and impaired arterial endothelial function. Continuous high-intensity exercise can lead to impaired endothelial function, and high-intensity interval exercise can enhance both normal and impaired endothelial function. In addition, it was demonstrated that the production of vasomotor factors, oxidative stress, and inflammatory response is involved in the regulation of arterial endothelial function under different-intensity exercise interventions. We posit that this synthesis will then provide a theoretical basis for choosing the appropriate exercise intensity and optimize the prescription of clinical exercise for persons with normal and impaired endothelium.

Neoantigens and their potential applications in tumor immunotherapy.

The incidence of malignant tumors is increasing, the majority of which are associated with high morbidity and mortality rates worldwide. The traditional treatment method for malignant tumors is surgery, coupled with radiotherapy or chemotherapy. However, these therapeutic strategies are frequently accompanied with adverse side effects. Over recent decades, tumor immunotherapy shown promise in demonstrating notable efficacy for the treatment of cancer. With the development of sequencing technology and bioinformatics algorithms, neoantigens have become compelling targets for cancer immunotherapy due to high levels of immunogenicity. In addition, neoantigen-based vaccines have demonstrated potential for cancer therapy, primarily by augmenting T-cell responses. Neoantigens have also been shown to be effective in immune checkpoint blockade therapy. Therefore, neoantigens may serve to be predictive biomarkers and synergistic treatment targets in cancer immunotherapy. The aim of the present review was to provide an overview of the recent progress in the classification, screening and clinical application of neoantigens for cancer therapy.

[A method of exosomes extraction from large-volume cell perfusate].

Objective: To establish an efficient method for extracting exosomes from large-volume cell perfusate. Methods: EA.HY926, an immortalized cell line produced by the hybridization of human umbilical vein endothelial cells and human lung adenocarcinoma cell line A549, was cultured with M199 culture medium containing 10% fetal bovine serum. Flexcell STR-4000 parallel plate flow chamber system was employed to apply shear stress to EA.HY926. And then the perfusate was collected. The cell debris was removed by centrifugation. The supernatant was freeze-dried into the dry powder and was resuspended by small-volume medium. The dialysis was used to desalt and purify the suspension. The exoEasy Maxi Kit was used to extract the exosomes. The morphology of exosomes was observed by electron microscopy. The size of exosomes was detected by nanometer particle size analyzer. The activity of exosomes was detected by PKH26 staining. BCA protein quantification method was used to detect the protein concentration of exosomes. The expressions of exosomal specific proteins CD9 and CD81 were detected by Western blot. The quantitative RT-PCR was used to detect the expression of related genes in the exosomes. Results: The exosomes extracted by this method were uniform in size, showing a typical and complete vesicle-like structure. The particle size was concentrated at 30～150 nm, and the peak value was at 97.63 nm, indicating that the size was appropriate and the purity was high. Moreover, exosomes-specific protein CD9 and CD81 were expressed. PKH26 could bind to the membranous structure of exosomes and exosomes could be efficiently taken up by cells. Endothelial cells-associated CD31, vWF mRNA, and microRNA molecules such as miR-126, miR-21, miR-155 were expressed in exosomes secreted by EA.HY926. Conclusion: This method can effectively extract structurally intact, high-concentration, high-quality exosomes from large-volume cell perfusate.

Function of Krüppel­like factor 2 in the shear stress­induced cell differentiation of endothelial progenitor cells to endothelial cells.

The present study aimed to evaluate the effects of Krüppel­like factor 2 (KLF2) on the differentiation of endothelial progenitor cells (EPCs) to endothelial cells (ECs) induced by shear stress, and to investigate the corresponding mechanisms. Cultured rat late EPCs were exposed to shear stress (12 dyn/cm2) for different lengths of time. Reverse transcription­quantitative polymerase chain reaction (RT­qPCR) was used to measure the initial KLF2 mRNA levels in each group. Subsequently, the EPCs were treated with anti­integrin ß1 or ß3 antibodies to block integrin ß1 and ß3, respectively, or cytochalasin D to destroy F­actin, and the subsequent expression levels of KLF2 in EPCs were measured. Then, KLF2 small interfering RNAs (siRNAs) were transfected into EPCs, and RT­qPCR was used to measure the mRNA expression level of KLF2. Additionally, flow cytometry was applied to evaluate the protein levels of cluster of differentiation 31 (CD31) and the von Willebrand factor (vWF), and the regulatory effects of KLF2 in the promoter region of vWF were determined via a luciferase assay. High shear stress upregulated KLF2 expression, while blocking integrin ß1/ß3 or destroying F­actin resulted in a corresponding decrease in KLF2 expression. Downregulation of KLF2 expression by siKLF2 inhibited the differentiation of EPCs to ECs under shear stress conditions, while the expression of EC­specific markers decreased, including CD31 and vWF. Various lengths of the vWF promoter region induced vWF expression, and EPCs co­transfected with KLF2 significantly increased the vWF expression levels compared with the group treated with vWF alone (P<0.01). In conclusion, shear stress may upregulate KLF2 expression, which may be associated with the integrin­actin cytoskeleton system. Most importantly, the shear stress­induced differentiation of EPCs may be mediated by KLF2.

Inhibition of Kir2.1 channel-induced depolarization promotes cell biological activity and differentiation by modulating autophagy in late endothelial progenitor cells.

AIMS: Endothelial progenitor cells (EPCs) play a crucial role in postnatal angiogenesis and neovascularization. Inward rectifier potassium channel 2.1 (Kir2.1) have been identified in EPCs. However, the effect of Kir2.1 on EPC function is not known. Here, we try to establish the role of Kir2.1 channels in EPC function and to provide first insights into the mechanisms. METHODS AND RESULTS: We first observed that the expression of Kir2.1 gradually decreased with the differentiation of EPCs into ECs in gene and protein levels. Treatment with the Kir2.1-selective inhibitor ML133 or knockdown of Kir2.1 by shRNA triggered EPC depolarization and promoted EPC biological functions, such as migration, adhesion, angiogenesis and differentiation into ECs in vitro. Transplantation of ML133-treated or Kir2.1 knockdown EPCs facilitated re-endothelialization in the rat injured arterial segment and inhibited neointima formation in vivo. In parallel, ML133 significantly enhanced autophagy and autophagic flux. After suppression of autophagy by 3-methyladenine (3-MA), the effects of ML133 on in vitro function and in vivo endothelialization capacity of EPCs were significantly inhibited. Mechanistically, ML133-induced autophagy was mediated at least partly by increased the activity of reactive oxygen species (ROS) that likely through intracellular calcium. CONCLUSION: Our study indicates that blocking or knockdown Kir2.1 results in a moderate depolarization of EPCs, which directly participated in enhancing EPC functions both in vitro and in vivo. In the mean time, autophagy signaling pathway is, at least in part, involved in this process. It may provide a potential target for the treatment or prevention of vascular injury and disease.

Resveratrol protects late endothelial progenitor cells from TNF-α-induced inflammatory damage by upregulating Krüppel-like factor-2.

Cardiovascular risk factors can negatively influence late endothelial progenitor cell (EPCs) number and functions, thus EPCs biology is a clinical implications for cardiovascular diseases. The present study aimed to investigate the potential protective effects of resveratrol (RES) on tumor necrosis factor (TNF)­α­induced inflammatory damage in late endothelial progenitor cells (EPCs) and to elucidate the underlying mechanisms. Late EPCs at passages 3­5 were pretreated with RES at a concentration of 20 µmol/l for 12 h and subsequently incubated with TNF­α (10 ng/ml) for 24 h. The adhesion, migration, proliferation and vasculogenesis of EPCs were subsequently detected. Furthermore, the mRNA expression levels of intercellular adhesion molecule­1 (ICAM­1) and monocyte chemoattractant protein­1 (MCP­1) were measured by reverse transcription­quantitative polymerase chain reaction (RT­qPCR). Nitric oxide (NO) levels in the supernatant were determined using a colorimetric assay kit. Additionally, the mRNA and protein expression of Krüppel­like factor­2 (KLF2) was determined by RT­qPCR and western blot analysis, respectively. The results indicated that TNF­α markedly inhibited the proliferation, adhesion, migration and vasculogenesis of late EPCs. However, RES ameliorated the effects induced by TNF­α. Furthermore, exposure of EPCs to TNF­α decreased the levels of NO secretion and KLF2 expression at the mRNA and protein levels, but upregulated the levels of inflammatory factors, including ICAM­1 and MCP­1, compared with the control group. RES significantly inhibited TNF­α­induced inflammatory damage through upregulation of KLF2 expression and downregulation of the expression of ICAM­1 and MCP­1. In conclusion, RES may exert protective effects on the cardiovascular system, as demonstrated by the amelioration of TNF-α-induced inflammation in EPCs following RES treatment, and may therefore be used in the future for the prevention of cardiovascular disease.

[Effects of endothelial progenitor cells on proliferation and biological function of hepatic stellate cells under shear stress].

OBJECTIVE: To investigate the effects of endothelial progenitor cells (EPCs) under shear stress on the biological function such as proliferation, adhesion, migration, apoptosis and expression of α-smooth muscle actin (α-SMA), collagen-I and collagen-Ⅲ of hepatic stellate cells (HSCs). METHODS: HSCs and EPCs were inoculated into the upper and lower layers of the co-culture chamber respectively and co-incubated for 24 hours. Then, 12 dyne/cm2 shear stress was applied to EPCs cells for another 24 hours. After that, proliferation, adhesion, migration and apoptosis of HSCs were detected by cell counting kit-8 (CCK-8) kit, cell adherent assay, Boyden cell migration assay and flow cytometry respectively. Fluorescence quantitative PCR and Western blot were used to detect the mRNA and protein expression of alpha -SMA, collagen I and collagen-Ⅲ in HSCs. RESULTS: Under shear stress, EPCs ecological niche could obviously inhibit the proliferation, adhesion and migration of HSCs, promote the apoptosis of HSCs, and down-regulate the mRNA and protein expression of collagen-I, collagen-Ⅲ in HSC cells. CONCLUSIONS: Under shear stress, EPCs ecological niche could inhibit the fibrosis development of HSCs to a certain extent.

Shear stress-mediated changes in the expression of complement regulatory protein CD59 on human endothelial progenitor cells by ECM-integrinαVß3-F-actin pathway in vitro.

Membrane regulatory proteins, such as CD46, CD55, and CD59, prevent excess complement activation and to protect cells from damage. Previous investigations confirmed that shear stress in the physiological range was more favorable for endothelial progenitor cells (EPCs) to repair injured vascular endothelial cells and operates mainly in atheroprotective actions. However, detailed events that contribute to shear stress-induced protection in EPCs, particularly the mechanisms of signal transduction, remain poorly understood. In this study, we observed shear stress-mediated changes in the expression of complement regulatory proteins CD46, CD55, and CD59 on human EPCs and focused on the mechanical transmission mechanism in transformed cells in response to the ECM-F-actin pathway in vitro. Shear stress was observed to promote the expression of complement regulatory protein CD59, but not CD46 or CD55, on EPCs. In addition, the shear stress-induced CD59 expression was confirmed to be associated with the ECM components and was alleviated in EPCs pretreated with GRGDSP, which inhibits ECM components-integrin interaction. Furthermore, shear stress also promotes the rearrangement and polymerization of F-actin. However, shear stress-induced CD59 expression was reduced when the F-actin stress fiber formation process was delayed by Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP) or destroyed by cytochalasin D (Cyto D), while Jasplakinolide (JAS) reversed the expression of CD59 through promotion of F-actin polymerization and its stabilizing capacities. Our results indicates that shear stress is an important mediator in EPC expression of CD59 regulated by the ECM-F-actin pathway, which is a key factor in preventing membrane attack complex (MAC) -mediated cell autolysis.

F­actin cytoskeleton reorganization is associated with hepatic stellate cell activation.

The activation of hepatic stellate cells (HSCs) is involved in the development of hepatic fibrosis. Previous studies have indicated that the acquisition of certain properties by activated HSCs is highly dependent on the reorganization of the actin cytoskeleton. However, direct evidence showing that the reorganization of the actin cytoskeleton is responsible for HSC activation is lacking. The aim of the present study was to investigate the role of cytoskeletal reorganization during HSC activation and to clarify the underlying mechanism. HSC-T6 cells were treated either with the F-actin stabilizer jasplakinolide (Jas) or the depolymerizer cytochalasin D (Cyto D). The actin cytoskeleton was evaluated via assessment of stress fiber formation. Furthermore, the activation properties of HSCs, including proliferation, adhesion, migration and the expression of α-smooth muscle actin (α-SMA) and collagen 1, were investigated in vitro. The results showed that Jas and Cyto D affected the actin distribution in HSC-T6 cells. Treatment with Jas resulted in thick actin bundles and a patchy appearance in the cytoplasm in HSC-T6 cells. In parallel, polymerization of actin microfilaments induced by Jas upregulated the expression of α-SMA and collagen 1, and also enhanced the migration and adhesion properties of HSC-T6 cells. Furthermore, the activation of HSC-T6 cells induced by the reorganization of the actin cytoskeleton was associated with the p38 mitogen-activated protein kinase (p38 MAPK) pathway. In conclusion, the present study suggests that the reorganization of the F-actin cytoskeleton is associated with HSC activation and that the p38 MAPK pathway is involved in this process. The inhibition of F-actin reorganization may thus be a potential key factor or molecular target for the control of liver fibrosis or cirrhosis.

Shear stress regulates late EPC differentiation via mechanosensitive molecule-mediated cytoskeletal rearrangement.

BACKGROUND: Previous studies have demonstrated that endothelial progenitor cells (EPCs), in particular late EPCs, play important roles in endothelial maintenance and repair. Recent evidence has revealed shear stress as a key regulator for EPC differentiation. However, the underlying mechanisms regulating the shear stress-induced EPC differentiation have not been understood completely. The present study was undertaken to further investigate the effects of shear stress on the late EPC differentiation, and to elucidate the signal mechanism involved. METHODOLOGY/PRINCIPAL FINDING: In vitro and in vivo assays revealed that cytoskeletal remodeling was involved in the shear stress-upregulated expression of endothelial markers vWF and CD31 in late EPCs, with subsequently increased in vivo reendothelialization after arterial injury. Moreover, shear stress activated several mechanosensitive molecules including integrin ß1, Ras, ERK1/2, paxillin and FAK, which were all involved in both cytoskeletal rearrangement and cell differentiation in response to shear stress in late EPCs. CONCLUSIONS/SIGNIFICANCE: Shear stress is a key regulator for late EPC differentiation into endothelial cells, which is important for vascular repair, and the cytoskeletal rearrangement mediated by the activation of the cascade of integrin ß1, Ras, ERK1/2, paxillin and FAK is crucial in this process.

Puerarin accelerates re-endothelialization in a carotid arterial injury model: impact on vasodilator concentration and vascular cell functions.

Puerarin, a main isoflavone glucoside derived from the Chinese medicine Radix puerariae, has been employed clinically to prevent and treat various cardiovascular disorders. However, little research has been performed to identify the in vivo effects of puerarin on the re-endothelialization and neointimal hyperplasia of injured vessels, and its detailed mechanisms of action remain to be elucidated. In this study, Sprague-Dawley rats were treated with puerarin at the dosages of 0, 50, and 100 mg·kg(-1)·day(-1) i.p. after balloon carotid denudation for 2 weeks. The results showed that puerarin accelerated re-endothelialization after surgery, resulting in a significant reduction of neointima formation. Moreover, puerarin increased the serum levels of vasodilators, such as nitric oxide and prostaglandin I(2), in a dose-dependent manner. In vitro, puerarin exhibited protective effects on late endothelial progenitor cells and mature endothelial cells, and inhibitory effects on the migration of vascular smooth muscle cells. Taken together, these data indicate that puerarin accelerates re-endothelialization, inhibits neointima formation, and attenuates vascular remodeling at sites of arterial injury, possibly due to the cytoprotective effects on endothelial lineage and the suppression of vascular smooth muscle cell migration.

Hyperglycaemia exerts deleterious effects on late endothelial progenitor cell secretion actions.

Endothelial progenitor cells (EPCs) play a fundamental role in tissue regeneration and vascular repair both by differentiating into endothelial cells and by secretion of vasoactive substances that promote angiogenesis and maintain vascular homeostasis. It has previously been shown that hyperglycaemia impairs early and late EPC functions, such as differentiation, proliferation and adhesion. However, its role in the regulation of the production of vasoactive substances in EPCs, especially in late EPCs, is less well defined. We investigated the effects of hyperglycaemia on the production of vasodilator, fibrinolytic and angiogenic growth factors, and also on the activity of superoxide dismutase (SOD) in late EPCs. For this purpose, late EPCs were incubated with different concentrations of D-glucose (5-40 mmol/L) for 24 hr. Levels of nitric oxide (NO), tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), prostaglandin I(2) (PGI(2)), vascular endothelial growth factor (VEGF) and the activity of SOD were measured by enzyme-linked immunosorbent assay (ELISA). Under high glucose stress conditions, late EPCs exhibited lower levels of NO, t-PA, PAI-1, PGI(2) and VEGF compared to control medium (5 mmol/L glucose). Moreover, high glucose was also observed to decrease the activity of SOD in late EPCs. These results suggest that hyperglycaemia-induced impairment of late EPC secretion functions could contribute to the development of vascular disease in diabetes.

Actin stabilization by jasplakinolide affects the function of bone marrow-derived late endothelial progenitor cells.

BACKGROUND: Bone marrow-derived endothelial progenitor cells (EPCs), especially late EPCs, play a critical role in endothelial maintenance and repair, and postnatal vasculogenesis. Although the actin cytoskeleton has been considered as a modulator that controls the function and modulation of stem cells, its role in the function of EPCs, and in particular late EPCs, remains poorly understood. METHODOLOGY/PRINCIPAL FINDING: Bone marrow-derived late EPCs were treated with jasplakinolide, a compound that stabilizes actin filaments. Cell apoptosis, proliferation, adhesion, migration, tube formation, nitric oxide (NO) production and endothelial NO synthase (eNOS) phosphorylation were subsequently assayed in vitro. Moreover, EPCs were locally infused into freshly balloon-injured carotid arteries, and the reendothelialization capacity was evaluated after 14 days. Jasplakinolide affected the actin distribution of late EPCs in a concentration and time dependent manner, and a moderate concentration of (100 nmol/l) jasplakinolide directly stabilized the actin filament of late EPCs. Actin stabilization by jasplakinolide enhanced the late EPC apoptosis induced by VEGF deprivation, and significantly impaired late EPC proliferation, adhesion, migration and tube formation. Furthermore, jasplakinolide attenuated the reendothelialization capacity of transplanted EPCs in the injured arterial segment in vivo. However, eNOS phosphorylation and NO production were increased in late EPCs treated with jasplakinolide. NO donor sodium nitroprusside (SNP) rescued the functional activities of jasplakinolide-stressed late EPCs while the endothelial NO synthase inhibitor L-NAME led to a further dysfunction induced by jasplakinolide in late EPCs. CONCLUSIONS/SIGNIFICANCE: A moderate concentration of jasplakinolide results in an accumulation of actin filaments, enhancing the apoptosis induced by cytokine deprivation, and impairing the proliferation and function of late EPCs both in vitro and in vivo. NO donor reverses these impairments, suggesting the role of NO-related mechanisms in jasplakinolide-induced EPC downregulation. Actin cytoskeleton may thus play a pivotal role in regulating late EPC function.

Shear stress augments the endothelial cell differentiation marker expression in late EPCs by upregulating integrins.

Vascular endothelial cell injury has been implicated in the onset of atherosclerosis. A number of previous studies have demonstrated that endothelial progenitor cells (EPCs), in particular late EPCs, play important roles in endothelial maintenance and repair. Recent evidence has revealed shear stress as a key regulator for EPC differentiation. However, the detailed events that contribute to the shear stress-induced EPC differentiation, in particular the mechanisms of mechanotransduction, remain to be identified. The present study was undertaken to further confirm the effects of shear stress on the late EPC differentiation, and to investigate the role of integrins in this procedure. Shear stress was observed to increase the expression of endothelial cell differentiation markers, such as vWF and CD31, in late EPCs isolated from rat bone marrow. Shear stress moreover enhanced the mRNA expression of integrin subunits ß(1) and ß(3) in a time-dependent manner, and also upregulated specific integrins in late EPCs plated on substrates containing various extracellular matrix (ECM) proteins. In addition, the shear stress-induced vWF and CD31 expression were found to be related to the levels of integrin ß(1) and ß(3), and were inhibited in late EPCs treated with RGD peptide (Gly-Arg-Gly-Asp-Asn-Pro, GRGDNP) that blocks the binding of integrins to the extracellular matrix. Additionally, this increase was also attenuated by both anti-ß(1) integrin and anti-ß(3) integrin antibodies. The integrin subunits ß(1) and ß(3) thus play important roles in regulating the shear stress-induced endothelial cell differentiation marker expression in late EPCs. This may provide novel insights into the mechanisms of mechanotransduction in shear stress-mediated late EPC differentiation.

Advanced glycation end products impair the migration, adhesion and secretion potentials of late endothelial progenitor cells.

BACKGROUND: Endothelial progenitor cells (EPCs), especially late EPCs, play a critical role in endothelial maintenance and repair, and postnatal vasculogenesis. Advanced glycation end products (AGEs) have been shown to impair EPC functions, such as proliferation, migration and adhesion. However, their role in the regulation of the production of vasoactive substances in late EPCs is less well defined. METHODS: Passages of 3~5 EPCs, namely late EPCs, were cultured with different concentrations (0~500 µg/ml) of AGEs, and the apoptosis, adhesion and migration were subsequently determined. The release of vasoactive substances, such as stromal cell-derived factor-1 (SDF-1), nitric oxide (NO), prostaglandin I2 (PGI2), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA), and in addition the activity of superoxide dismutase (SOD), were evaluated by ELISA. At the same time, the gene and protein expressions of CXCR4 were assayed by real-time RT-PCR and western-blot. RESULTS: AGEs promoted late EPC apoptosis. Moreover, AGEs impaired late EPC migration and adhesion in a concentration-dependent manner. Accordingly, the production of SDF-1 was decreased by AGEs. Although the CXCR4 expressions of late EPCs were up-regulated for AGE concentrations of 50, 100 or 200 µg/ml, a marked decrease was observed for the higher concentration of 500 µg/ml. Furthermore, co-culturing with AGEs decreased the levels of NO, t-PA, PGI2, and the activity of SOD but up-regulated the production of PAI-1. CONCLUSION: Our data provide evidence that AGEs play an important role in impairing late EPC functions, which could contribute to the development of vascular diseases in diabetes.