Jinchuan Yan

Patients with antiphospholipid syndrome have been identified to have higher incidence rates of atherosclerosis (AS) due to the elevated levels of anti‑β2‑glycoprotein I (β2GPI) antibody (Ab). Our previous studies revealed that the anti‑β2GPI Ab formed a stable oxidized low‑density lipoprotein (oxLDL)/β2GPI/anti‑β2GPI Ab complex, which accelerated AS development by promoting the accumulation of lipids in macrophages and vascular smooth muscle cell. However, the effects of the complex on endothelial cells, which drive the initiation and development of AS, remain unknown. Thus, the present study aimed to determine the proinflammatory roles of the oxLDL/β2GPI/anti‑β2GPI Ab complex in human umbilical vein endothelial cells (HUVECs) in an attempt to determine the underlying mechanism. Reverse transcription‑quantitative PCR, enzymy‑linked immunosorbent assay, western blotting and immunofluorescence staining were performed to detect the expressions of inflammation related factors and adhesion molecules. Monocyte‑binding assay was used to investigate the effects of oxLDL/β2GPI/anti‑β2GPI Ab complex on monocyte adhesion to endothelial cells. The results demonstrated that the oxLDL/β2GPI/anti‑β2GPI Ab complex upregulated the expression of Toll‑like receptor (TLR)4 and the levels of NF‑κB phosphorylation in HUVECs, and subsequently enhanced the expression levels of inflammatory cytokines, including TNF‑α, IL‑1β and IL‑6, as well as those of adhesion molecules, such as intercellular adhesion molecule 1 and vascular adhesion molecule 1. In addition, the complex facilitated the recruitment of monocytes by promoting the secretion of monocyte chemotactic protein 1 in HUVECs. Notably, the described effects of the oxLDL/β2GPI/anti‑β2GPI Ab complex in HUVECs were abolished by either TLR4 or NF‑κB blockade. In conclusion, these findings suggested that the oxLDL/β2GPI/anti‑β2GPI Ab complex may induce a hyper‑inflammatory state in endothelial cells by promoting the secretion of proinflammatory cytokines and monocyte recruitment, which was discovered to be largely dependent on the TLR4/NK‑κB signaling pathway.

Combination of antiangiogenesis and immunotherapy may be an effective strategy for treatment of solid tumors. Our previous work reported that activation of CD137 signaling promotes intraplaque angiogenesis. A number of studies have demonstrated that vascular endothelial growth factor receptor 2 (VEGFR2) is a key target for angiogenesis. However, it is unknown whether CD137-mediated angiogenesis is related to VEGFR2. In this study, we investigated the effect of CD137 on the VEGFR2 expression and explored the underlying mechanisms of CD137-mediated angiogenesis. Knock-out of CD137 in ApoE^-/- mice significantly decreased neovessel density in atherosclerotic plaques. CD137 silencing or inhibition attenuated endothelial cell (ECs) proliferation, migration, and tube formation. We found activation of CD137 signaling for increased VEGFR2 transcription and translation steadily. Moreover, CD137 signaling activated phosphorylated VEGFR2 (Tyr1175) and the downstream Akt/eNOS pathway, whereas neutralizing CD137 signaling weakened the activation of VEGFR2 and the downstream Akt/eNOS pathway. The aortic ring assay further demonstrated that CD137 signaling promoted ECc sprouting. Inhibition of VEGFR2 by siRNA or XL184 (cabozantinib) and inhibition of downstream signaling by LY294002 (inhibits AKT activation) and L-NAME (eNOS inhibitor) remarkably abolished proangiogenic effects of CD137 signaling both in vitro and ex vivo. In addition, the condition medium from CD137-activated ECs and vascular endothelial growth factor A (VEGFA) had similar effects on ECs that expressed high VEGFR2. Additionally, activating CD137 signaling promoted endothelial secretion of VEGFA, while blocking CD137 signaling attenuated VEGFA secretion. In conclusion, activation of CD137 signaling promoted sprouting angiogenesis by increased VEGFA secretion and the VEGFR2/Akt/eNOS pathway. These findings provide a basis for stabilizing intraplaque angiogenesis through VEGFR2 intervatioin, as well as cancer treatment via combination of CD137 agonists and specific VEGFR2 inhibitors.

Background Ischemia-reperfusion injury (IRI) frequenting follows successful PCI for STEMI and is recognized by multiple modalities. Multilayer speckle tracking echocardiography (STE) has the potential of detecting myocardial dysfunction in different myocardial layers. Our objective was to describe the changes in layer-specific myocardial function over the 24 hours after successful PCI for ST-elevation myocardial infarction (STEMI). Methods Patients (n = 120) with STEMI and no prior myocardial infarction underwent echocardiography prior to PCI, immediately after and at 3- and 24-hours post-PCI. Worsening focal dysfunction (WFD) was defined as an immediate reduction, compared to the pre-PCI value, in the amplitude of endo-myocardial longitudinal strain (endo-MLS) within the infarction territory. Results Patients with WFD (52%) had further reductions in endo-MLS, mid-MLS, and epi-MLS in the infarction region immediately post-PCI; at 3 hours strain began to improve and continued to improve at 24 hours. Reductions of endo-MLS strain were more evident than those of global, mid-MLS, and epi-MLS. This same pattern was seen in each of the ischemic territories of the anterior descending, circumflex, and right coronary arteries. Immediate improvement in endo-MLS following PCI was seen in 48% of patients. The time from symptom onset to balloon time was markedly longer in those with WFD (P < .0001). Conclusions Multilayer SPE is a sensitive method that identifies serial alterations in focal myocardial function following successful PCI for STEMI. Layer-specific reductions in endo-MLS appeared more evident than decreases in global LV strain. Prolonged total ischemic time prior to PCI was directly related to the incidence of WFD.

Background: Assessment of left ventricular (LV) diastolic function is part of routine echocardiographic examinations. Accuracy of the 2016 ASE/EACVI algorithm to detect LV diastolic dysfunction in patients with a normal LV ejection fraction (LVEF) has been examined but simultaneous measurements of LV pressures and echocardiographic parameters of diastolic function are sparse.Methods: The accuracy of multiple echo parameters of diastolic dynamics and the 2016 guidelines were assessed by simultaneous transthoracic echocardiography and LV pressure recordings in 120 patients (derivation cohort) and 60 patients (validation cohort) with suspected coronary artery disease and normal LVEF. Receiver‐operating characteristic (ROC) curves defined optimal cut points for each echocardiographic parameter. A new algorithm was proposed to estimate LV diastolic pressures using 5 parameters based on ROC data: tricuspid regurgitation velocity >280cm/s, average e' 13, velocity of pulmonary vein A‐wave reversal >32 cm/s, and left atrial volume index >32 mL/m². Performances of the 2016 guidelines and a proposed algorithm were examined for detecting a LV pre‐A >12 and LV end‐diastolic pressure (LVEDP) >15 mm Hg.Results: In the derivation cohort, the 2016 algorithm identified an elevated LVEDP >15 mm Hg with an accuracy of 74.2% (63.8–82.9); the modified algorithm improved accuracy to 86.0% (77.6–92.1), P < .05. In the validation cohort, the proposed algorithm improved sensitivities with accuracies remaining like the 2016 algorithm.Conclusions: LV diastolic pressures in patients with normal LVEF were reliably assessed by the 2016 guidelines. The proposed algorithm improved sensitivities and may improve the accuracies for detecting abnormal LV filling pressures.

Background. Advanced glycation end products play an important role in diabetic atherosclerosis. The effects of advanced glycation end products (AGEs) on vascular smooth muscle cell- (VSMC-) derived foam cell formation and phenotypic transformation are unknown.Methods. Serological and histological samples were obtained from diabetic amputation patients and accident amputation patients from the Affiliated Hospital of Jiangsu University. CD68/Actin Alpha 2 (ACTA2) coimmunofluorescence sections were used to quantify the number of VSMCs with macrophage-like phenotypes. Western blotting was used to detect the expression of the receptor of advanced glycation end products in vascular samples. Enzyme-linked immunosorbent assay (ELISA) was used to evaluate the level of serum Nε-carboxymethyl-lysine (CML). In vitro oil red O staining was used to examine lipid accumulation in VSMCs stimulated by CML. The expression of VSMCs and macrophage markers was measured by western blotting and quantitative real-time PCR. Furthermore, changes in VSMC migration and secretion were detected by the Transwell assay and ELISA.Results. In the arterial plaque sections of diabetic patients, VSMCs transformed to a macrophage-like phenotype. The serum CML and RAGE levels in the plaques were significantly higher in the diabetes group than those in the healthy control group and were significantly related to the number of macrophage-like VSMCs. CML stimulation promoted intracellular lipid accumulation. However, CML stimulation decreased the expression of VSMC markers and increased the expression of macrophage phenotype markers. Finally, CML promoted smooth muscle cell migration and the secretion of proinflammatory-related factors.Conclusions. CML induces VSMC-derived foam cell formation, and VSMCs transdifferentiate to a macrophage-like state, which may be mediated by the activation of RAGE.

Background. Endothelial dysfunction and apoptosis resulting from oxidative stress can lead to the development of atherosclerosis. Our group has previously showed that CD137 signaling contributes to the progression of atherosclerosis and the vulnerability of plaques. The aim of this study is to investigate the effects of CD137 signaling in atherosclerosis on endothelial cells (ECs) apoptosis and to explore the underlying mechanisms. Methods. Serum samples were collected from 11 patients with acute myocardial infarction and 4 controls. Peritoneal injection of agonist-CD137 recombinant protein in ApoE^−/− mice was used to determine whether CD137 signaling can promote apoptosis in vivo, and human umbilical vein endothelial cells treated with agonist-CD137 recombinant protein, M5580 (a Nrf2 pathway agonist) and CAPE (a NF-κB pathway inhibitor) were used to explore the effect of Nrf2 and NF-κB pathway in CD137 signaling-induced ECs apoptosis in vitro. Results. ELISA showed that Bcl-2 in the serum of AMI patients was lower than that of the control group, while TNF-α and sCD137 were higher than that of the control group. Confocal microscopy and Western blot analysis showed that the nuclear translocation of Nrf2 in the agonist-CD137 group was significantly inhibited, and the expression of its downstream antioxidant enzymes was also decreased when compared with control. Immunofluorescence and Western blot results showed that the nuclear translocation of NF-κB in the agonist-CD137 group was enhanced, and ELISA results showed that the secretion of proinflammatory cytokines in the agonist-CD137 group was increased. Immunofluorescence results revealed that ROS production in the agonist-CD137 group was higher than that in control, M5580 (a Nrf2 pathway agonist) and CAPE (a NF-κB pathway inhibitor) groups. In vitro studies using HUVECs and in vivo studies using high-fat-fed ApoE^−/− mice showed that the number of apoptotic endothelial cells was the highest in the agonist-CD137 group. By contrast, both M5580 and CAPE treatments were able to reduce CD137 induced ECs apoptosis. Conclusions. Our results showed that CD137 signaling promotes ECs apoptosis through prooxidative and proinflammatory mechanisms, mediated by Nrf2 and NF-κB pathways, respectively.

The role of exosomes derived from endothelial cells (ECs) in the progression of atherosclerosis (AS) and inflammation remains largely unexplored. We aimed to investigate whether exosome derived from CD137‐modified ECs (CD137‐Exo) played a major role in AS and to elucidate the potential mechanism underlying the inflammatory effect. Exosomes derived from mouse brain microvascular ECs treated with agonist anti‐CD137 antibody were used to explore the effect of CD137 signalling in AS and inflammation in vitro and vivo. CD137‐Exo efficiently induced the progression of AS in ApoE^−/− mice. CD137‐Exo increased the proportion of Th17 cells both in vitro and vivo. The IL‐6 contained in CD137‐Exo which is regulated by Akt and NF‐КB pathway was verified to activate Th17 cell differentiation. IL‐17 increased apoptosis, inhibited cell viability and improved lactate dehydrogenase (LDH) release in ECs subjected to inflammation induced by lipopolysaccharide (LPS). The expression of soluble intercellular adhesion molecule1 (sICAM‐1), monocyte chemoattractant protein‐1 (MCP‐1) and E‐selectin in the supernatants of ECs after IL‐17 treatment was dramatically increased. CD137‐Exo promoted the progression of AS and Th17 cell differentiation via NF‐КB pathway mediated IL‐6 expression. This finding provided a potential method to prevent local and peripheral inflammation in AS.

Background: Angiogenesis in atherosclerotic plaque is an important factor causing plaque hemorrhage, vulnerability, and rupture, and different phenotypes of macrophages have different effects on angiogenesis. Our previous study has demonstrated CD137-CD137L signaling, a pair of inflammatory costimulatory molecules, can promote angiogenesis in atherosclerotic plaque. Therefore, we aimed to investigate whether this signaling could affect angiogenesis by regulating phenotypic transition of macrophages. Methods: Male mouse primary peritoneal macrophages were extracted by intraperitoneal injection of thioglycollate, and then flow cytometry was used to detect the expression of CD137. Flow cytometry, Western blotting, quantitative real-time PCR, and enzyme-linked immunosorbent assay (ELISA) were used to assess the phenotypic changes of macrophages after different treatment. Mouse brain microvascular endothelial cells (bEnd.3) were cocultured with macrophages, and tube formation was assessed to examine angiogenesis. Results: We found that the number of junctions and branches of bEnd.3 were increased when CD137-CD137L signaling was activated, while such number was further increased when bEnd.3 were cocultured with macrophages. Flow cytometry showed that CD137 was expressed on almost all primary peritoneal macrophages. The expression of CD86 was decreased in the agonist CD137L group and increased in the agonist CD137L + inhibitory anti-CD137 antibody group after adding the CD137 inhibitor. The expression of CD206 in each group exhibited opposite trend compared with CD86. Moreover, the expression of inducible nitric oxide synthase at the mRNA, and protein levels were decreased after stimulating CD137-CD137L signaling, and such downward trend was reversed when CD137-CD137L signaling was inhibited. Furthermore, the expression of arginase-1 was opposite to that of inducible nitric oxide synthase. Enzyme-linked immunosorbent assay indicated that the content of interleukin-12 (IL-12) in the supernatant of macrophages in the agonist CD137L group was lower than that in the control group, and its content in the inhibited group was higher than that in the activated group. The change of interleukin-10 (IL-10) content in macrophage supernatant was opposite to that of IL-12. When AKT serine/threonine kinase 1 (Akt1) inhibitor was used to inhibit the phenotypic transformation of macrophages induced by CD137-CD137L, the number of junctions and branches formed by bEnd.3 was decreased compared with the coculture group. Conclusions: These results indicated that CD137-CD137L signaling could promote angiogenesis by regulating phenotypic transition of macrophages of male mice.

Background . Macrophage‐derived foam cells play a central role in atherosclerosis, and their ultimate fate includes apoptosis, promotion of vascular inflammation, or migration to other tissues. N ε ‐Carboxymethyl‐lysine (CML), the key active component of advanced glycation end products, induced foam cell formation and apoptosis. Previous studies have shown that the Vav1/Rac1 pathway affects the macrophage cytoskeleton and cell migration, but its role in the pathogenesis of diabetic atherosclerosis is unknown. Methods and Results . In this study, we used anterior tibiofibular vascular samples from diabetic foot amputation patients and accident amputation patients, and histological and cytological tests were performed using a diabetic ApoE ^-/- mouse model and primary peritoneal macrophages, respectively. The results showed that the atherosclerotic plaques of diabetic foot amputation patients and diabetic ApoE ^-/- mice were larger than those of the control group. Inhibition of the Vav1/Rac1 pathway reduced vascular plaques and promoted the migration of macrophages to lymph nodes. Transwell and wound healing assays showed that the migratory ability of macrophage‐derived foam cells was inhibited by CML. Cytoskeletal staining showed that advanced glycation end products inhibited the formation of lamellipodia in foam cells, and inhibition of the Vav1/Rac1 pathway restored the formation of lamellipodia. Conclusion . CML inhibits the migration of foam cells from blood vessels via the Vav1/Rac1 pathway, and this process affects the formation of lamellipodia.