A new role for host annexin A2 in establishing bacterial adhesion to vascular endothelial cells: lines of evidence from atomic force microscopy and an in vivo study.

Understanding bacterial adhesion is challenging and critical to our understanding of the initial stages of the pathogenesis of endovascular bacterial infections. The vascular endothelial cell (EC) is the main target of Rickettsia, an obligately intracellular bacterium that causes serious systemic disease in humans and animals. But the mechanism(s) underlying bacterial adherence to ECs under shear stress from flowing blood prior to activation are unknown for any bacteria. Although host surface annexin a2 (ANXA2) has been identified to participate in efficient bacterial invasion of epithelial cells, direct evidence is lacking in the field of bacterial infections of ECs. In the present study, we employ a novel, anatomically based, in vivo quantitative bacterial-adhesion-to-vascular-EC system, combined with atomic force microscopy (AFM), to examine the role of endothelial luminal surface ANXA2 during rickettsial adherence to ECs. We also examined whether ANXA2 antibody affected binding of Staphylococcus aureus to ECs. We found that deletion of ANXA2 impeded rickettsial attachment to the ECs in vitro and blocked rickettsial adherence to the blood vessel luminal surface in vivo. The AFM studies established that EC surface ANXA2 acts as an adherence receptor for rickettsiae, and that rickettsial adhesin OmpB is the associated bacterial ligand. Furthermore, pretreatment of ECs with anti-ANXA2 antibody reduced EC surface-associated S. aureus. We conclude that the endothelial surface ANXA2 plays an important role in initiating pathogen-host interactions, ultimately leading to bacterial anchoring on the vascular luminal surface.

Comparison of detergent-based decellularization protocols for the removal of antigenic cellular components in porcine aortic valve.

BACKGROUND: Various detergent-based protocols are used to remove cells and cellular debris in porcine aortic valve (PAV). However, the removal of antigenic cellular components has not been thoroughly elucidated to date. In this study, we used 4 detergent-based protocols to decellularize PAVs and aimed to evaluate their effects on removing antigenic cellular components. METHODS: Porcine aortic valves were decellularized using sodium dodecyl sulfate (SDS), SDS in combination with sodium deoxycholate (SDS/SD), Triton X-100, and Triton X-100 in combination with SD (Triton X-100/SD), respectively. Untreated PAVs were used as controls. Immunohistochemical and SDS-polyacrylamide gel electrophoresis (SDS-PAGE) analyses were performed to determine the removal of antigenic protein components. Histological, biochemical, and biomechanical analyses were performed to determine the preservation and mechanical properties of the extracellular matrix. PAV tissues were implanted subcutaneously in Sprague Dawley rats to evaluate the host immune response. Implanted PAVs were taken out at the indicated time points for histological and immunohistochemical examinations. RESULTS: All 4 protocols effectively removed the membrane antigenic proteins major histocompatibility complex I molecule and galactose-α-1,3 galactose. The SDS/SD protocol was the most effective method to remove the cytoplasmic cytoskeletal proteins, vimentin and α-SMA, and SDS alone partly removed vimentin protein. The SDS/SD protocol was the most effective method to remove nuclear DNA with residual DNA below 50 ng/mg, followed by the SDS protocol with residual DNA of 74.9 ng/mg. The SDS protocol was the most effective method to remove proteins ranged from 10 to 55 kDa, followed by the SDS/SD protocol. SDS and SDS/SD PAV implants attracted fewer neutrophils in vivo on postoperative day 3. The infiltration of macrophages and T lymphocytes was significantly lower in SDS and SDS/SD implants on days 14 and day 28. All of the decellularized protocols that were examined greatly reduced the contents of collagen, elastin, and glycosaminoglycan compared to controls. Biomechanical analysis revealed significant differences in ultimate tensile strength and Young's modulus between control PAVs and decellularized PAVs generated using SDS, SDS/SD, Triton X-100, or Triton X-100/SD. CONCLUSIONS: These results indicated that SDS-based protocols more effectively removed antigenic cellular components compared to Triton X-100-based protocols. These results are clinically significant because complete removal of antigenic determinants is critical to decrease adverse immune-mediated and inflammatory responses to a PAV when used in xenogeneic application.

Evidence of Osteogenic Regulation in Calcific Porcine Aortic Valves.

BACKGROUND: Chemically cross-linked animal tissues, such as porcine aortic valves (PAVs) have many documented advantages over mechanical valves. However, calcification is the major underlying pathologic process that results in bioprosthetic valve failure. Recently, several reports described the expression of noncollagenous bone matrix proteins in bioprosthetic valves and suggested an actively regulated process of tissue repair. METHODS: Thirty-one explanted PAVs with evidence of calcification were collected and examined for the protein expression implicated in myofibroblast activation, osteoblast differentiation, and bone matrix deposition by using immunohistochemistry. RESULTS: The mean duration that PAVs were implanted was 11.5 ± 5.6 years, ranging from 12 months to 28 years. Pearson correlation analysis showed a significant relationship between the duration and valvular calcification (r = 0.3818, P = .034). The number of vimentin-positive mesenchymal cells in explanted PAVs was significantly lower than that of unused PAVs (P < .01). However, increased expression of α-smooth muscle actin (α-SMA) (P < .01), proliferating cell nuclear antigen (PCNA, P < .01), Cbfa1/Runx2 (P < .01), osterix (P = .0126), bone sialoprotein (BSP, P < .01), osteocalcin (P < .01), and osteopontin (P < .01) was found in explanted PAVs. Immunohistochemical staining of alkaline phosphatase (ALP) and osteocalcin was negative in the unused PAVs. In explanted PAVs, the expression level of these 2 proteins was also significantly increased. CONCLUSIONS: Our results support the view that PAV calcification is an actively regulated process with osteogenic signaling activation.

Experimental observation on a new chimney-shaped mechanical valve completely implanted above the mitral annulus in animals.

Current commercially available prosthetic valves suffer from limited size, high requirements for implantation technique, subvalvular structural destruction, and valve dysfunction due to proliferation of fibrous endothelial tissue. This study aims to perform the preclinical large animal experiments for surgically implanting a chimney-shaped artificial mechanical heart valve with zero left ventricular occupancy, which fully accommodates the movement of the valve leaflets in the valve frame and realizes completely supra-annular surgical implantation. A total of 7 sheep underwent the replacement of artificial valve, and 5 sheep survived normally until anatomical examination. The mechanical properties of these artificial mitral valves remain functionally normal. There was no obvious thromboembolism around the artificial valve and in the important organs. The tissue layer of suture ring was completely organized and endothelialized, and the thickness of tissue layer was about 0.6-1.0 mm. The follow-up of echocardiography showed that the left ventricular ejection fraction was normal (60-70%) before and 6 months after operation. The results of transvalvular pressure gradient and blood flow velocity of artificial valve were normal. Left ventricular retrograde angiography showed that the artificial valve was completely located in the left atrium with good position and normal opening and closing. There was no obvious perivalvular leakage and other abnormalities. At 3 and 6 months, there were no obvious abnormalities in blood routine test, liver and kidney function, and other indexes. The new chimney-shaped artificial mechanical valve implanted completely above the mitral annulus had good wear resistance, histocompatibility, and antithrombotic and hemodynamic performance.

Transjugular Transcatheter Tricuspid Valve Implantation of LuX-Valve Bioprosthesis in a Preclinical Model.

The purpose of this preclinical study in a sheep model was to confirm the feasibility and safety of the LuX-Valve transjugular tricuspid valve (TV) replacement apparatus and to optimize the implantation procedure before beginning first-in-man study. The LuX-Valve was implanted in a sheep model (n = 8) via transjugular approach. Six of eight sheep underwent successful implantation procedure on beating heart. The first two sheep died during the prostheses deployment. In the remaining 6 sheep that survived, postoperative echocardiography results showed there was no paravalvular leakage (PVL) and central tricuspid regurgitation in 5 animals, whereas 1 animal had mild PVL. The mean transvalvular gradient was 1.1 ± 0.9 mm Hg at the 4-week follow-up. No right ventricular outflow tract (RVOT) obstruction, device malposition, pericardial effusion, coronary artery compression, or arrhythmias were observed. This technology may be a promising alternative for TR patients who are at high risk for open-heart surgery. Transjugular tricuspid valved-stent implantation. a Transjugular tricuspid valve replacement in a sheep model. b and c Valved stent. d, e, and f Schematic depiction of the implantation procedure.

Characteristics of pericardial interstitial cells and their implications in pericardial fibrocalcification.

Pericardial fibrocalcification (PF) is a prominent feature of human pericardial pathology, including constrictive pericarditis and, to a lesser extent, degenerated autologous pericardial substitutes. However, the role of pericardial interstitial cells (PICs) in the pathogenesis of PF has yet to be established. Using a combination of histology and immunohistochemistry, we showed that the critical cellular event in PF in situ was the transdifferentiation of PICs into myofibroblasts/osteoblasts and that the percentage of myofibroblasts/osteoblasts correlated positively with the severity of PF. In vitro studies demonstrated that PICs, similar to mesenchymal stem cells, had the potential to differentiate along adipogenic, osteogenic, chondrogenic or myogenic lineages. However, PICs exhibited a more limited self-renewal capacity and a lower expression of Oct4 (POU5F1) and Kruppel-like transcription factor Klf4, underwent earlier senescence and spontaneously transdifferentiated into myofibroblasts/osteoblasts. Quantitative-real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) confirmed that the mRNA levels of α-smooth muscle actin (α-SMA), alkaline phosphatase (ALP), core-binding factor α1/runt-related transcription factor2 (Cbfa1/Runx2), transforming growth factor (TGF)-ß1 and bone morphogenetic protein (BMP)-2 were upregulated as the passage number increased. The mRNA level of platelet-derived growth factor (PDGF)-AA was also significantly upregulated with higher levels at passage 3. Ectopic expression of Oct4 and Klf4 enhanced the colony formation of PICs and selectively impaired induction of genes involved in transdifferentiation into myofibroblasts/osteoblasts (α-SMA, ALP, Cbfa1/Runx2, PDGF-AA and BMP-2). These data, while offering new insights into the biology of PICs, reinforce the central role of these cells in cell-mediated PF and may assist in future strategies to treat fibrocalcific pericardial diseases.

MicroRNA-98 and microRNA-214 post-transcriptionally regulate enhancer of zeste homolog 2 and inhibit migration and invasion in human esophageal squamous cell carcinoma.

BACKGROUND: The enhancer of zeste homolog 2 (EZH2) was found to be overexpressed and associated with tumor metastasis in esophageal squamous cell carcinoma (ESCC). On the other hand, it was reported that miR-26a, miR-98, miR-101, miR-124, miR-138 and miR-214 could inhibit the expression of EZH2 in some tumors. However, the role of miRNAs in the regulation of EZH2 expression in human ESCC has not been documented. The aim of this study was to determine the role of these miRNAs in the regulation of tumor metastasis via EZH2 overexpression in human ESCC. METHODS AND RESULTS: The expression of these miRNAs and EZH2 mRNA were examined by qPCR and the expression of EZH2 protein was detected by western blot. The role of these miRNAs in migration and invasion was studied in ESCC cell line (Eca109) transfected with miRNA mimics or cotransfected with miRNA mimics and pcDNA-EZH2 plasmid (without the 3'-UTR of EZH2). Through clinical investigation, we found that miR-98 and miR-214 expression was significantly lower in ESCC tissues than in matched normal tissues, and the expression level of miR-98 and miR-214 was inversely correlated to EZH2 protein expression and the clinical features such as pathological grade, tumor stage and lymph node metastasis in ESCC. In Eca109 cells, overexpression of miR-98 and miR-214 significantly inhibited the migration and invasion of ESCC cells, which was reversed by transfection of EZH2. CONCLUSIONS: These findings suggest that decreased expression of miR-98 and miR-214 might promote metastasis of human ESCC by inducing accumulation of EZH2 protein.

PRAF3 induces apoptosis and inhibits migration and invasion in human esophageal squamous cell carcinoma.

BACKGROUND: Prenylated Rab acceptor 1 domain family member 3 (PRAF3) is involved in the regulation of many cellular processes including apoptosis, migration and invasion. This study was conducted to investigate the effect of PRAF3 on apoptosis, migration and invasion in human esophageal squamous cell carcinoma (ESCC). METHODS: The expression of PRAF3 mRNA and protein in primary ESCC and the matched normal tissues (57cases) was determined by quantitative RT-PCR and Western blot. Immunohistochemical analysis of PRAF3 expression was carried out in paraffin-embedded sections of ESCC and correlated with clinical features. The role of PRAF3 in apoptosis, migration and invasion was studied in ESCC cell lines of Eca109 and TE-1 through the adenovirus mediated PRAF3 gene transfer. The effect of PRAF3 on apoptosis was analyzed by annexin V-FITC assay. The regulation of PRAF3 on migration was determined by transwell and wounding healing assay, while the cellular invasion was analyzed by matrigel-coated transwell assay. RESULTS: We found that the expression of PRAF3 was significantly down-regulated in ESCC tissue compared with the matched normal tissue and was correlated with the clinical features of pathological grade, tumor stage and lymph node metastasis. Moreover, overexpression of PRAF3 induced cell apoptosis through both caspase-8 and caspase-9 dependent pathways, and inhibited cell migration and invasion by suppressing the activity of both MMP-2 and MMP-9 in human ESCC cell lines. CONCLUSIONS: Our data suggest that PRAF3 plays an important role in the regulation of tumor progression and metastasis and serves as a tumor suppressor in human ESCC. We propose that PRAF3 might be used as a potential therapeutic agent for human ESCC.

MicroRNA-203 inhibits cell proliferation by repressing ΔNp63 expression in human esophageal squamous cell carcinoma.

BACKGROUND: This study was performed to investigate the effect of microRNA-203 (miR-203) and ΔNp63 on cell proliferation and the functional connection between miR-203 and ΔNp63 in ESCC. METHODS: We employed 2 human ESCC cell lines, Eca109 and TE-1, as the model system. The effect of miR-203 and ΔNp63 on cell proliferation was determined in cells transfected with miR-203 mimic and ΔNp63 small interfering RNA (siRNA), respectively. The regulation of ΔNp63 expression in ESCC cells by miR-203 was studied by luciferase reporter assay, RT-PCR and western blot analysis in cells transfected with miR-203. The effect of ΔNp63 re-expression on miR-203 induced inhibition of cell proliferation was studied by cell proliferation assay in cells cotransfected with miR-203 and pcDNA-ΔNp63 plasmid (without the 3'-UTR of ΔNp63). RESULTS: We found that both miR-203 and ΔNp63 siRNA signicantly inhibited cell proliferation in ESCC. MiR-203 could down-regulate endogenous ΔNp63 expression at the posttranscriptional level. Moreover, re-expression of ΔNp63 in cells transfected with miR-203 significantly attenuated the miR-203 induced inhibition of cell proliferation. CONCLUSIONS: Our data implied that miR-203 could inhibit cell proliferation in human ESCC through ΔNp63-mediated signal pathway. Therefore, we propose that miR-203 might be used as a therapeutic agent for human ESCC.

Intrathecal siRNA against Toll-like receptor 4 reduces nociception in a rat model of neuropathic pain.

BACKGROUND: Neuropathic pain is characterized by hyperalgesia, allodynia and spontaneous pain. It often occurs as a result of injury to peripheral nerves, dorsal root ganglions (DRG), spinal cord, or brain. Recent studies have suggested that Toll-like receptor 4 (TLR4) might play a role in neuropathic pain. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we investigated the role of TLR4 in a rat chronic constriction injury (CCI) model and explored the feasibility of treating neuropathic pain by inhibiting TLR4. Our results demonstrated that intrathecal siRNA-mediated suppression of TLR4 attenuated CCI-induced mechanical allodynia and thermal hyperalgesia through inhibiting the activation of NF-kappaB p65 and production of proinflammatory cytokines (e.g., TNF-alpha and IL-1 beta). CONCLUSIONS/SIGNIFICANCE: These findings suggest that suppression of TLR4 mediated by intrathecally administered siRNA may be a new strategy for the treatment of neuropathic pain.

Self-renewal and chemotherapy resistance of p75NTR positive cells in esophageal squamous cell carcinomas.

BACKGROUND: p75NTR has been used to isolate esophageal and corneal epithelial stem cells. In the present study, we investigated the expression of p75NTR in esophageal squamous cell carcinoma (ESCC) and explored the biological properties of p75NTR+ cells. METHODS: p75NTR expression in ESCC was assessed by immunohistochemistry. p75NTR+ and p75NTR- cells of 4 ESCC cell lines were separated by fluorescence-activated cell sorting. Differentially expressed genes between p75NTR+ and p75NTR- cells were determined by real-time quantitative reverse transcription-PCR. Sphere formation assay, DDP sensitivity assay, 64copper accumulation assay and tumorigenicity analysis were performed to determine the capacity of self-renewal, chemotherapy resistance and tumorigenicity of p75NTR+ cells. RESULTS: In ESCC specimens, p75NTR was found mainly confined to immature cells and absent in cells undergoing terminal differentiation. The percentage of p75NTR+ cells was 1.6%-3.7% in Eca109 and 3 newly established ESCC cell lines. The expression of Bmi-1, which is associated with self-renewal of stem cells, was significantly higher in p75NTR+ cells. p63, a marker identified in keratinocyte stem cells, was confined mainly to p75NTR+ cells. The expression of CTR1, which is associated with cisplatin (DDP)-resistance, was significantly decreased in p75NTR+ cells. Expression levels of differentiation markers, such as involucrin, cytokeratin 13, beta1-integrin and beta4-integrin, were lower in p75NTR+ cells. In addition, p75NTR+ cells generated both p75NTR+ and p75NTR- cells, and formed nonadherent spherical clusters in serum-free medium supplemented with growth factors. Furthermore, p75NTR+ cells were found to be more resistant to DDP and exhibited lower 64copper accumulation than p75NTR- cells. CONCLUSION: Our results demonstrated that p75NTR+ cells possess some characteristics of CSCs, namely, self-renewal and chemotherapy resistance. Chemotherapy resistance of p75NTR+ cells may probably be attributable to decreased expression of CTR1.

[Isolation and identification of cancer stem cells from human esophageal carcinoma].

OBJECTIVE: To isolate and identify cancer stem cells from esophageal carcinoma cells (ECCs) using cell surface marker p75NTR. METHODS: ECCs cell lines were established with ECCs collected from 38 surgically resected specimens. Flow cytometry was used to identify the p75NTR positive cells therein that were isolated then using magnetic activated cell sorting (MACS) method. The growing characteristics in DMEM medium and capability of colony-forming in soft agar of the p75NTR positive cells were evaluated ex vivo with MTT method. p75NTR positive cells of different concentrations were subcutaneously injected into the backs of Balb/c nude mice and PBS was injected into the contralateral back, and then tumorigenesis was observed, 8 weeks later the mice were killed with their tumors taken out to undergo microscopy. RESULTS: Eight ECCs cell lines were established, 6 of which were found to contain 0.32%-3.35% of p75NTR positive cells. The purity of p75NTR positive cells isolated by MACS was up to 90%. MTT result showed that population doubling time of the p75NTR positive cells was (17+/-3) hours, significantly shorter than that of the p75NTR negative cells [(37+/-7) hours, P<0.01]. The colony-forming rate in soft agar of the p75NTR positive cells was (45.9%+/-8.9%), significantly higher than that of the p75NTR negative cells [(3.7%+/-2.1%), P<0.01]. As few as 2000 p75NTR positive cells gave rise to new tumors in xenotransplantation, with a tumorigenic ability 50 times as high as that of the p75NTR negative cells. CONCLUSION: p75NTR positive cells carry some properties of cancer stem cells, such as the ability of self-renewal, differentiation and proliferation and demonstrate higher ability of colony-forming ex vivo and tumorigenesis in vivo.

[Recombinant adeno-associated virus mediated RNA interference of angiogenin expression inhibits cell growth of human lung adenocarcinoma].

OBJECTIVE: To study the inhibition of angiogenin (ANG) expression in human lung squamous cancer cell strain-A549 through adeno-associated virus (AAV)-mediated RNA-interference, and therefore to observe its effect on the growth of cancer cells and tumor formation. METHODS: Recombinant AAV expressing H1-promoter-induced small-interference- RNA (siRNA) targeting ANG (AAV-shANG) was constructed, and then transfected into A549 cells. A549 cells and cells transfected with AAV-Null were used as the control groups. The effects of the reduced expression of ANG by RNAi from AAV-shANG on the growth, formation, reproduction, apoptosis, and microvessel-density of the carcinoma were observed. RESULTS: In vitro experiment showed that AAV-shANG was constructed successfully, There was an significant decrease in the expression of ANG protein 72 h after transfection, compared with the normal A459 cells and AAV-Null cells (P < 0.01). Cell cycle analysis showed that the proliferation index (PI) of normal A549 cells, AAV-Null cells and AAVshANG cells were 0.32 +/- 0.29, 0.35 +/- 0.38 and 0.31 +/- 0.43, respectively. There was no statistic difference in the PIs among the 3 groups (P > 0.05). In vivo experiment using thymus-defect mice showed that, there was an remarkable reduction in the mass and volume of tumors in AAV-shANG transfected group, compared to the control groups. Microvessel-density was 9.4 +/- 1.5, 9.8 +/- 2.1 and 5.7 +/- 1.9, respectively in the 3 groups, a statistic difference among the AAV-shANG-transfected group, the normal A549 group and the AAV-Null transfected group. The percentages of apoptotic cells in each group were (7.7 +/- 3.1)%, (8.5 +/- 5.4)%, (17.1 +/- 8.6)%, respectively, the experimental group being higher than those of the control groups. Positive rates of PCNA were (84.8 +/- 9.7)%, (85.8 +/- 9.8)%, and (70.4 +/- 10.1)%, respectively, the AAV-shANG transfected cancer cells showing a lower PCNA index than the control groups. CONCLUSION: AAV-mediated expression of siRNA could reduce the expression of ANG in cancer cells, significantly enough to inhibit cell proliferation, promote cell apoptosis and inhibit tumor growth.

Exchange protein directly activated by cAMP plays a critical role in regulation of vascular fibrinolysis.

Plasmin-mediated fibrinolysis at the surface of vascular endothelial cells (SVEC) plays a key role in maintaining vascular hemostasis, in which the cAMP pathway participates. After externalization to the SVEC, annexin A2 (ANXA2) serves as a platform for conversion of plasminogen to plasmin. Here we describe a regulatory role of the exchange protein directly activated by cAMP (EPAC) in ANXA2 externalization and vascular fibrinolysis. Knockout of EPAC1 in mice results in a decreased ANXA2 expression on the SVEC associated with increased fibrin deposition and fibrinolytic dysfunction. Reduced levels of EPAC1 are also found in endocardial tissues beneath atrial mural thrombi in patients. Notably, administration of recombinant ANXA2 ameliorates fibrinolytic dysfunction in the EPAC1-null mice. Mechanistically, EPAC1 regulates the SVEC plasminogen conversion depended on ANXA2. EPAC1 promotes tyrosine-23 phosphorylation of ANXA2, a prerequisite for its recruitment to the SVEC. Our data thus reveal a novel regulatory role for EPAC1 in vascular fibrinolysis.

Therapeutic potential of angiogenin modified mesenchymal stem cells: angiogenin improves mesenchymal stem cells survival under hypoxia and enhances vasculogenesis in myocardial infarction.

BACKGROUND: To examine the effects of angiogenin modified mesenchymal stem cells (MSCs) on ventricular remodeling and cardiac function in a rat model of acute myocardial infarction. METHODS: MSCs were transfected with adenoviral vectors carrying either angiogenin (MSC(AdANG)) or EGFP (MSC(AdEGFP)). Angiogenin gene amplification, protein expression and cell death were assayed after hypoxic treatment. DiI labeled MSC(AdANG) and MSC(AdEGFP) were injected into infracted heart. Six weeks after cell transplantation, echocardiography and histological study were performed. RESULTS: After hypoxia treatment, angiogenin modified MSCs effectively expressed angiogenin for at least 14 days. The death of MSC(AdANG) was one-third of MSCAd(EGFP), and 50% of untreated MSCs. In the infracted myocardium, the number of DiI labeling cells in MSC(AdANG) group with high angiogenin expression was three-fold that in MSC(AdEGFP) group. Echocardiograms suggested that angiogenin modified MSCs significantly improved left ventricular (LV) systolic and diastolic function. Histological study confirmed that ventricular remodeling was attenuated significantly in MSC(AdANG) group. Furthermore, vasculogenesis was enhanced significantly in MSC(AdANG) group as measured by both factor VIII and alpha-SMA staining. CONCLUSION: Angiogenin modified MSCs enhanced the tolerance of engrafted MSCs to hypoxia injury in vitro and improved their viability in infracted hearts, thus helping preserve the LV contractile function and attenuate LV remodeling through vasculogenesis.

Angiopoietin-1 targeted RNA interference suppresses angiogenesis and tumor growth of esophageal cancer.

AIM: To determine the inhibitory effect of the adenovirus-based angiopoietin-1 (Ang-1) targeted small interfering RNA expression system (Ad/Ang-1si) on the expression of the Ang-1 gene, cell growth and apoptosis in human esophageal cancer cell line Eca109. METHODS: siRNA-expressing adenovirus targeting Ang-1 gene was constructed using the Ad Easy System. Cultured Eca109 cells were transfected with Ad/Ang-1si (Eca109/Ang-1si), and Ad/si was used to infect Eca109 cells as control (Eca109/si). Ang-1 gene expression and concentration was determined with RT-PCR and ELISA, respectively. Human umbilical vein endothelial cell (HUVEC) migration and proliferation were analyzed. After s.c. injection into athymic nu/nu mice, the tumor growth, vessel density and apoptosis of each group was also determined. RESULTS: HUVEC migration induced by conditioned medium from Ang-1si-transfected Eca109 cells was significantly less than that induced by conditioned medium from Eca109 cells and control adenovirus-transfected Eca109 cells. Furthermore, after s.c. injection into athymic nu/nu mice, the tumor growth and cell apoptosis of Ad/Ang-1si -expressing Eca109 cells was significantly lower than that of parental or control adenovirus-transfected cells. Vessel density assessed by CD31 immunohistochemical analysis and Ang-1 expression by RT-PCR were also decreased. CONCLUSION: The targeting Ang-1 may provide a therapeutic option for esophageal cancer.

Efficient decellularization for bovine pericardium with extracellular matrix preservation and good biocompatibility.

OBJECTIVES: In this study, we sought to explore an efficient decellularization protocol for bovine pericardia with better extracellular matrix preservation and good biocompatibility. METHODS: Bovine pericardia were decellularized by sodium dodecyl sulphate (SDS), SDS + sodium deoxycholate (SD), Triton X-100 (TX), TX + SD (TS), freeze-thaw cycles + SDS + SD (FSS) and freeze-thaw cycles + TX + SD (FTS), respectively. Untreated pericardia were used as native control. Histological examination, residual cellular content analysis, biochemical and biomechanical evaluations and cytotoxicity assay were performed to investigate decellularization efficiency, xenoantigens removal, extracellular matrix preservation and biocompatibility. In vivo biocompatibility was evaluated using a subcutaneous implantation method in rats. RESULTS: Among these protocols, FSS and FTS protocols were the most effective methods to remove both the DNA material and the galactose-α-1,3-galactose antigen. TX, TS and FTS bovine pericardia maintained the collagen content and had no cytotoxicity to human umbilical vein endothelial cells. The contents of elastin and glycosaminoglycan were lost to different degrees after decellularization, with the highest content of preservation with TX, followed by TS and FTS. Consistently, no significant difference was found between native bovine pericardia and TX, TS or FTS bovine pericardia. In vivo, FTS implants had minimal infiltration of macrophages and T-lymphocytes, with no histological evidence of peri-implant necrosis and calcification. CONCLUSIONS: These results suggested that the FTS protocol showed optimal decellularization results with better extracellular matrix preservation and good biocompatibility. It may be a suitable protocol for producing a suitable scaffold for heart tissue engineering.

Prognostic value of association of OCT4 with LEF1 expression in esophageal squamous cell carcinoma and their impact on epithelial-mesenchymal transition, invasion, and migration.

Esophageal squamous cell carcinoma (ESCC) is a malignant disease with poor prognosis. Because of early metastasis prior to diagnosis and therapeutic resistance, ESCC has become one of the leading causes of cancer-related death. Here, we investigated the clinicopathological significance of the association of octamer-binding transcription factor 4 (OCT4) with lymphoid enhancer-binding factor 1 (LEF1) expression and the potential molecular mechanism in the epithelial-mesenchymal transition (EMT), invasion, and migration of ESCC. The expression of OCT4 and LEF1 was detected via immunohistochemistry analysis. High levels of LEF1 expression were observed in 95 ESCC specimens and were obviously associated with aberrant clinicopathological features and poor patient prognosis. Our previous study showed that OCT4 expression level is elevated in ESCC, and statistical analysis showed that the elevated expression of OCT4 and LEF1 in ESCC was significantly associated with histologic grade, lymph node metastasis, TNM stage, and poor patient prognosis. The specific inhibition of OCT4 expression via a lentivirus encoding OCT4-shRNA (LV-shOCT4) in Eca109 cells led to decreased levels of OCT4 and LEF1 in vitro. Additionally, we applied a rescue strategy by infecting LV-shOCT4 Eca109 cells with a LEF1 overexpression plasmid (p-LEF1) and detected changes in EMT, migration, and invasion. Unsurprisingly, the p-LEF1 group exhibited greater EMT, invasion, and migration than did the LV-shOCT4 and negative control groups. This study demonstrates for the first time the relationship between OCT4 and LEF1 expression. The combination of high expression of OCT4 and LEF1 was associated with clinicopathological features of atypical patients, and this combination might be an ideal prognostic factor in ESCC. OCT4 positively regulated LEF1 expression, and LEF1 mediated the effects of OCT4 in cancer cell EMT, invasion, and migration. The data presented here suggest that the inhibition of OCT4-LEF1 signaling may be a new therapeutic target for the treatment of ESCC.

The size-effect of gold nanoparticles and nanoclusters in the inhibition of amyloid-ß fibrillation.

A significant pathological signature of Alzheimer's disease (AD) is the deposition of amyloid-ß (Aß) plaques in the brain and the synaptic dysfunction and neurodegeneration associated with it. Compounds or drugs that inhibit Aß fibrillation are thus desirable to develop novel therapeutic strategies against AD. Conventional strategies usually require an elaborate design of their molecular structures. Here we report the size-effect of gold nanoparticles (AuNPs) and nanoclusters (AuNCs) in the inhibition of protein amyloidosis. Using l-glutathione stabilized AuNPs with different sizes and AuNCs as examples, we show that large AuNPs accelerate Aß fibrillation, whereas small AuNPs significantly suppress this process. More interestingly, AuNCs with smaller sizes can completely inhibit amyloidosis. Dynamic light scattering (DLS) experiments show that AuNCs can efficiently prevent Aß peptides from aggregation to larger oligomers (e.g. micelles) and thus avoid nucleation to form fibrils. This is crucially important for developing novel AD therapies because oligomers are the main source of Aß toxicity. This work presents a novel strategy to design anti-amyloidosis drugs, which also provides interesting insights to understand how biological nanostructures participate in vivo in Aß fibrillation from a new perspective.

Pericardial interstitial cell senescence responsible for pericardial structural remodeling in idiopathic and postsurgical constrictive pericarditis.

OBJECTIVE: Idiopathic and postsurgical constrictive pericarditis is characterized by pericardial structural remodeling that involves fibrosis, calcification, and inflammation. This study aimed to determine whether cell senescence was responsible for pericardial structural remodeling. METHODS: Pericardial interstitial cells derived from patients with idiopathic or postsurgical pericarditis (pericarditis cells) were harvested. Timing of senescence and differences in telomere length were compared between age- and sex-matched controls (nonpericarditis cells). Pericardial interstitial cells derived from normal pericardia were serially passaged until senescence (senescent cells). Apoptosis, collagen matrix, calcium deposition, chemoattractant properties, gene expression profiles, and paracrine effects of senescent cells were compared with nonsenescent cells of passage 2 (nonsenescent cells). RESULTS: Pericarditis cells displayed senescent changes, including short telomere length, large flattened cell sizes, positive staining for senescence-associated ß-galactosidase, and limited growth capacity. These senescent cells were resistant to apoptosis, produced more collagen matrix, deposited more calcium, and attracted more monocytes/lymphocytes than the nonsenescent cells. A cluster of genes involved in extracellular matrix deposition (connective tissue growth factor, fibronectin, collagen type I, collagen type III, and tissue inhibitors of metalloproteinase-1), calcium deposition (osteopontin, bone sialoprotein, osteonectin, and matrix Gla protein), and inflammatory cell recruitment (interleukin-6, chemoattractant protein-1, and tumor necrosis factor-α) were upregulated in senescent cells, whereas extracellular matrix-degrading enzyme (metalloproteinase-1 and metalloproteinase-3) was downregulated. Furthermore, senescent cells had the ability to promote the proliferation, differentiation, and senescence of neighboring cells. CONCLUSIONS: These findings suggest that senescent cells have characteristics promoting pericardial structural remodeling, but further work is needed to establish causation.