Low shear stress-induced blockage of autophagic flux impairs endothelial barrier and facilitates atherosclerosis in mice.

Atherosclerosis preferentially occurs in areas with low shear stress (LSS) and oscillatory flow. LSS has been demonstrated to correlate with the development of atherosclerosis. The sphingosine 1-phosphate receptor 1 (S1PR1), involving intravascular blood flow sensing, regulates vascular development and vascular barrier function. However, whether LSS affects atherosclerosis via regulating S1PR1 remains incompletely clear. In this study, immunostaining results of F-actin, ß-catenin, and VE-cadherin indicated that LSS impaired endothelial barrier function in human umbilical vein endothelial cells (HUVECs). Western blot analysis showed that LSS resulted in blockage of autophagic flux in HUVECs. In addition, autophagy agonist Rapamycin (Rapa) antagonized LSS-induced endothelial barrier dysfunction, whereas autophagic flux inhibitor Bafilomycin A1 (BafA1) exacerbated it, indicating that LSS promoted endothelial barrier dysfunction by triggering autophagic flux blockage. Notably, gene expression analysis revealed that LSS downregulated S1PR1 expression, which was antagonized by Rapa. Selective S1PR1 antagonist W146 impaired endothelial barrier function of HUVECs under high shear stress (HSS) conditions. Moreover, our data showed that expression of GAPARAPL2, a member of autophagy-related gene 8 (Atg8) proteins, was decreased in HUVECs under LSS conditions. Autophagic flux blockage induced by GAPARAPL2 knockdown inhibited S1PR1, aggravated endothelial barrier dysfunction of HUVECs in vitro, and promoted aortic atherosclerosis in ApoE-/- mice in vivo. Our study demonstrates that autophagic flux blockage induced by LSS downregulates S1PR1 expression and impairs endothelial barrier function. GABARAPL2 inhibition is involved in LSS-induced autophagic flux blockage, which impairs endothelial barrier function via downregulation of S1PR1.

CT-guided ozone-mediated lumbar-renal sympathetic denervation for resistant hypertension treatment: A pilot single-arm clinical trial.

BACKGROUND: Renal sympathetic denervation (RDN) reduces blood pressure (BP). METHODS: This single-arm open-label study enrolled patients with resistant hypertension (RH) and treat them by CT-guided ozone mediated lumbar-renal sympathetic denervation (L-RDN). The primary endpoint was to assess the changes of BP over 24-h ambulatory BP monitoring (ABPM) and to evaluate the anti-hypertensive medication burden (AHMB) at 3-month follow-up. This study was registered in Chictr.org.cn (ChiCTR2300071375). RESULTS: 17 patients (mean age 65.12 ± 10.77 years) with AHMB of 4.12 ± 1.11 were enrolled. After the procedure, 7 patients (46.7 %) matched the criteria for antihypertensive medication reduction. The AHMB decreased to 3.87 ± 0.96 for the whole objectives and from 3.87 ± 0.96 to 3.55 ± 0.78 for patients with normal baseline renal function. On top of the lessened AHMB, L-RDN further reduced morning systolic BP (SBP) by -8.6 ± 4.0 mmHg (p = 0.034) and diastolic BP (DBP) by -4.6 ± 2.1 mmHg (p = 0.032) for all participants and morning SBP by -13.2 ± 3.6 mmHg (p < 0.001), morning DBP by -6.2 ± 2.4 mmHg (p = 0.011) and daytime SBP by -4.1 ± 1.6 mmHg (p = 0.009) for those with normal baseline renal function at 3-month of follow-up. No adverse events were reported intra- and post operation. CONCLUSIONS: CT-guided ozone-mediated L-RDN might be an innovative approach of RDN for treating RH. Confirmatory studies are warranted.

Bivalirudin Attenuates Thrombin-Induced Endothelial Hyperpermeability via S1P/S1PR2 Category: Original Articles.

Aims: To explore the role of the Sphingosine 1-Phosphate (S1P)/Receptor2 (S1PR2) pathway in thrombin-induced hyperpermeability (TIP) and to test whether bivalirudin can reverse TIP via the S1P-S1PRs pathway. Methods and Results: Using western blot, we demonstrated that Human umbilical vein endothelial cells (HUVECs) that were cultured with 2 U/ml thrombin showed significantly increased S1PR2 expression while S1PR1and three kept unchanged. Such increment was attenuated by JTE-013 pretreatment and by presence of bivalirudin. Exposure of 2 U/ml of thrombin brought a higher level of S1P both intracellularly and extracellularly within the HUVECs by using ELISA detecting. Thrombin induced S1P and S1PR2 increment was restored by usage of PF543 and bivalirudin. Bivalirudin alone did not influenced the level of S1P and S1PR1,2, and S1PR3 compare to control group. As a surrogate of cytoskeleton morphology, phalloidin staining and immunofluorescence imaging were used. Blurry cell edges and intercellular vacuoles or spaces were observed along thrombin-exposed HUVECs. Presence of JTE-013 and bivalirudin attenuated such thrombin-induced permeability morphological change and presence of heparin failed to show the protective effect. Transwell chamber assay and probe assay were used to measure and compare endothelial permeability in vitro. An increased TIP was observed in HUVECs cultured with thrombin, and coculture with bivalirudin, but not heparin, alleviated this increase. JTE-013 treatment yielded to similar TIP alleviating effect. In vivo, an Evans blue assay was used to test subcutaneous and organ microvascular permeability after the treatment of saline only, thrombin + saline, thrombin + bivalirudin, thrombin + heparin or thrombin + JTE-013. Increased subcutaneous and organ tissue permeability after thrombin treatment was observed in thrombin + saline and thrombin + heparin groups while treatment of bivalirudin and JTE-013 absent this effect. Conclusion: S1P/S1PR2 mediates TIP by impairing vascular endothelial barrier function. Unlike heparin, bivalirudin effectively blocked TIP by inhibiting the thrombin-induced S1P increment and S1PR2 expression, suggesting the novel endothelial protective effect of bivalirudin under pathological procoagulant circumstance.

Spliced XBP1 promotes macrophage survival and autophagy by interacting with Beclin-1.

Macrophage autophagy plays an important role in the development of atherosclerosis, but the precise mechanism mediating this process is unclear. The potential role of the X-box binding protein 1 (XBP1), a crucial transduction factor that is involved in endoplasmic reticulum stress and the unfolded protein response, in bone marrow-derived macrophage autophagy is unknown. This study mainly explores the roles of XBP1 mRNA splicing in bone marrow-derived macrophage autophagy. The present study shows that the transient overexpression of spliced XBP1 via adenovirus-mediated gene transfer induces autophagy and promotes proliferation in bone marrow-derived macrophages via the down-regulation of Beclin-1, but that the sustained overexpression of spliced XBP1 leads to apoptosis. When XBP1 is down-regulated in bone marrow-derived macrophages using siRNA, rapamycin-induced autophagosome formation is ablated. Furthermore, we have detected the overexpression of XBP1 in areas of atherosclerotic plaques in the arteries of ApoE-/- mice. These results demonstrate that XBP1 mRNA splicing plays an important role in maintaining the function of bone marrow-derived macrophages and provide new insight into the study and treatment of atherosclerosis.

[Touchdown PCR and overlap extension PCR for generating CD133(+) cancer stem cell-selective adenovirus vector].

OBJECTIVE: To construct a replication-incompetent adenovirus vector targeting cancer stem cells by modified touchdown PCR and overlap extension PCR and investigate its infection efficiency in CD133(+) SW480 cells in vitro. METHODS: The two portions of the fiber gene encoding the Ad5 fiber knob domain with the HI loop deleted were amplified using two pairs of designed primers and then linked by overlap extension PCR. The product obtained was identified by sequencing and inserted into prokaryotic expression vector pEGFP-N1. The product, pEGFP-N1 KNOBδHI, contained a unique EcoRV restriction site in the deleted portion of the sequence encoding the HI loop. The gene sequences of the adenovirus fiber were amplified using both common PCR and overlap extension PCR, then identified by sequencing and inserted into pNEB193, resulting in pNEB-F5. CD133(+) SW480 cells were infected with the generated adenovirus vectors Ad5-GFP and Ad5FHI-GFP to investigate the infection efficiency using fluorescent microscope. RESULTS: The target fragments of expected sizes were amplified by touchdown PCR and overlap extension PCR, but not by common PCR. Ad5FHI-GFP showed a higher infection efficiency than Ad5-GFP in CD133(+) SW480 cells. CONCLUSION: Compared with common PCR, touchdown PCR and overlap extension PCR can significantly improve the specificity and efficiency of the PCR products for constructing CD133(+) cancer stem cell-selective adenovirus type 5 vector, which provides carriers for tumor-targeted gene therapy.

[Selection and identification of specific-binding peptides for cancer stem cell surface marker CD133].

OBJECTIVE: To select the peptides that specifically bind human cancer stem cell surface marker CD133 from the Ph.D.-7>(TM) phage peptide library. METHODS: With a biotinylated extracellular fragment of human cancer stem cell surface marker CD133 as the target protein, the CD133 high-affinity peptides were screened from the phage peptide library by liquid phase panning. The clones with high-binding force with human CD133 were then identified by sandwich ELISA and their single-stranded DNA was extracted to test the specificity by competitive ELISA. The amino acid sequences of the selected peptides derived from the phage DNA sequences were synthesized after sequence alignment analysis, and their capacity of binding with colorectal carcinoma cells was assessed by immunofluorescence technique. RESULTS: After 4 rounds of liquid phase selection, the phages capable of specific binding with human CD133 were effectively enriched, with an enrichment ratio of 388 times compared to that at the fourth and first rounds. Thirteen out of the 20 clones from the fourth round of panning were identified as positive clones, among which 11 had identical amino acid sequence of TISWPPR, and 2 had the sequence of STTKLAL, and the former sequence showed a stronger binding specificity to CD133. CONCLUSION: We have successfully obtained a peptide that specifically binds human CD133 from the Ph.D.-7(TM) phage peptide library, demonstrating the feasibility of screening small molecule high-affinity polypeptides from phage peptide library by liquid-phase panning.