Controlled angiogenesis in the heart by cell-based expression of specific vascular endothelial growth factor levels

Vascular endothelial growth factor (VEGF) can induce normal angiogenesis or the growth of angioma-like vascular tumors depending on the amount secreted by each producing cell because it remains localized in the microenvironment. In order to control the distribution of VEGF expression levels in vivo, we recently developed a high-throughput fluorescence-activated cell sorting (FACS)-based technique to rapidly purify transduced progenitors that homogeneously express a specific VEGF dose from a heterogeneous primary population. Here we tested the hypothesis that cell-based delivery of a controlled VEGF level could induce normal angiogenesis in the heart, while preventing the development of angiomas. Freshly isolated human adipose tissue-derived stem cells (ASC) were transduced with retroviral vectors expressing either rat VEGF linked to a FACS-quantifiable cell-surface marker (a truncated form of CD8) or CD8 alone as control (CTR). VEGF-expressing cells were FACS-purified to generate populations producing either a specific VEGF level (SPEC) or uncontrolled heterogeneous levels (ALL). Fifteen nude rats underwent intramyocardial injection of 10(7) cells. Histology was performed after 4 weeks. Both the SPEC and ALL cells produced a similar total amount of VEGF, and both cell types induced a 50%-60% increase in both total and perfused vessel density compared to CTR cells, despite very limited stable engraftment. However, homogeneous VEGF expression by SPEC cells induced only normal and stable angiogenesis. Conversely, heterogeneous expression of a similar total amount by the ALL cells caused the growth of numerous angioma-like structures. These results suggest that controlled VEGF delivery by FACS-purified ASC may be a promising strategy to achieve safe therapeutic angiogenesis in the heart.

Tumour budding is a strong and independent prognostic factor in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer that escapes detection and resists treatment. Tumour budding, defined as the presence of de-differentiated single tumour cells or small cell clusters at the invasive front of gastrointestinal carcinomas like colorectal, oesophageal, gastric and ampullary, is linked to adverse prognosis. Tumour budding has not yet been reported in PDAC.

Klf4 transcription factor is expressed in the cytoplasm of prostate cancer cells

BACKGROUND: Cancer initiation and progression might be driven by small populations of cells endowed with stem cell-like properties. Here we comparatively addressed the expression of genes encoding putative stemness regulators including c-Myc, Klf4, Nanog, Oct4A and Sox2 genes in benign prostatic hyperplasia (BPH) and prostate cancer (PCA). METHODS: Fifty-eight PCA and thirty-nine BPH tissues samples were used for gene expression analysis, as evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). The expression of specific Klf4 isoforms was tested by conventional PCR. Klf4 specific antibodies were used for protein detection in a tissue microarray including 404 prostate samples. RESULTS: Nanog, Oct4A and Sox2 genes were comparably expressed in BPH and PCA samples, whereas c-Myc and Klf4 genes were expressed to significantly higher extents in PCA than in BPH specimens. Immunohistochemical studies revealed that Klf4 protein is detectable in a large majority of epithelial prostatic cells, irrespective of malignant transformation. However, in PCA, a predominantly cytoplasmic location was observed, consistent with the expression of a differentially spliced Klf4α isoform. CONCLUSION: Klf4 is highly expressed at gene and protein level in BPH and PCA tissues but a cytoplasmic location of the specific gene product is predominantly detectable in malignant cells. Klf4 location might be of critical relevance to steer its functions during oncogenesis.

Microphthalmia in Texel sheep is associated with a missense mutation in the paired-like homeodomain 3 (PITX3) gene

Microphthalmia in sheep is an autosomal recessive inherited congenital anomaly found within the Texel breed. It is characterized by extremely small or absent eyes and affected lambs are absolutely blind. For the first time, we use a genome-wide ovine SNP array for positional cloning of a Mendelian trait in sheep. Genotyping 23 cases and 23 controls using Illumina's OvineSNP50 BeadChip allowed us to localize the causative mutation for microphthalmia to a 2.4 Mb interval on sheep chromosome 22 by association and homozygosity mapping. The PITX3 gene is located within this interval and encodes a homeodomain-containing transcription factor involved in vertebrate lens formation. An abnormal development of the lens vesicle was shown to be the primary event in ovine microphthalmia. Therefore, we considered PITX3 a positional and functional candidate gene. An ovine BAC clone was sequenced, and after full-length cDNA cloning the PITX3 gene was annotated. Here we show that the ovine microphthalmia phenotype is perfectly associated with a missense mutation (c.338G>C, p.R113P) in the evolutionary conserved homeodomain of PITX3. Selection against this candidate causative mutation can now be used to eliminate microphthalmia from Texel sheep in production systems. Furthermore, the identification of a naturally occurring PITX3 mutation offers the opportunity to use the Texel as a genetically characterized large animal model for human microphthalmia.

New developments in the area of factor XIII

To cite this article: Schroeder V, Kohler HP. New developments in the area of factor XIII. J Thromb Haemost 2013; 11: 234-44. Summary.  Coagulation factor (F)XIII is best known for its role in fibrin stabilization and cross-linking of antifibrinolytic proteins to the fibrin clot. From patients with congenital FXIII deficiency, it is known that FXIII also has important functions in wound healing and maintaining pregnancy. Over the last decade more and more research groups with different backgrounds have studied FXIII and have unveiled putative novel functions for FXIII. FXIII, with its unique role as a transglutaminase among the other serine protease coagulation factors, is now recognized as a multifunctional protein involved in regulatory mechanisms and construction and repair processes beyond hemostasis with possible implications in many areas of medicine. The aim of this review was to give an overview of exciting novel findings and to highlight the remarkable diversity of functions attributed to FXIII. Of course, more research into the underlying mechanisms and (patho-)physiological relevance of the many described functions of FXIII is needed. It will be exciting to observe future developments in this area and to see if and how these interesting findings may be translated into clinical practice in the future.

Comparative Czech and Polish Perspectives and Policies on the Eastern Enlargement of the EU and the Prominence of the German Factor

With the end of the Cold War, which for central and eastern Europe in many respects meant the real political end to the Second World War, Germany regained its central position in the region. The Federal Republic quickly established itself as a major political and economic partner for both the Czech Republic and Poland. More importantly, due to its support for the idea of EU and NATO enlargement. Germany also became the most active western advocate of the Czech and Polish 'return to Europe'. The question remains, however, of whether Germany's relations with Poland and the Czech Republic can mature into a close axis like that enjoyed between Paris and Bonn/Berlin, or whether they will continue to develop along the lines of 'strategic congruence' but 'emotional mistrust and reserve'. The research here looked at three aspects of this question. First it considered the idea of a link between perceptions of Germany and broader considerations of European integration in Poland and the Czech Republic and outlined the ways in which Germany has motivated Czech and Polish activities and policies on EU membership. The team then focused upon on-going Czech and Polish EU integration strategies and sought to identify the actual ways in which Germany's advocacy of EU enlargement in manifest in cooperation 'on the ground'. The group concluded by considering prospects for Czech/German and Polish/German cooperation in the context of the enlarged European Union.

Vascular endothelial growth factor-A and aldosterone: relevance to normal pregnancy and preeclampsia

Aldosterone levels are markedly elevated during normal pregnancy but fall even though volume contracts when preeclampsia occurs. The level of aldosterone in either condition cannot be explained solely by the activity of the renin-angiotensin II system. In normal gestation, vascular endothelial growth factor (VEGF) is thought to maintain vascular health, but its role in adrenal hormone production is unknown. We hypothesized that the role of VEGF in the adrenal gland is to maintain vascular health and regulate aldosterone production. Here, we demonstrate that supernatant of endothelial cells grown in the presence of VEGF enhanced aldosterone synthase activity in human adrenocortical cells. VEGF either alone or combined with angiotensin II increased aldosterone production in adrenal cells. These data suggest that endothelial cell-dependent and independent activation of aldosterone is regulated by VEGF. In contrast to angiotensin II, VEGF did not upregulate the steroidogenic acute regulatory protein. Consistent with this observation, angiotensin II stimulated both aldosterone and cortisol synthesis from progesterone, whereas VEGF stimulated selectively aldosterone production. In rats, overexpression of soluble fms-like tyrosine kinase-1, an endogenous VEGF inhibitor, led to adrenocortical capillary rarefaction and fall in aldosterone concentrations that correlated inversely with soluble fms-like tyrosine kinase-1 levels. These findings may explain why aldosterone increases so markedly during normal gestation and why preeclampsia, a condition characterized by high soluble fms-like tyrosine kinase-1, is associated with inappropriately low aldosterone levels in spite of relatively lower plasma volumes.

Sialic acid binding immunoglobulin-like lectins may regulate innate immune responses by modulating the life span of granulocytes

The regulation of cell death is a key element in building up and maintaining both innate and adaptive immunity. A critical role in this process plays the tumor necrosis factor (TNF)/nerve growth factor (NGF) receptor family of death receptors. Recent work suggests that sialic acid binding immunoglobulin (Ig) -like lectins (Siglecs) are also empowered to transmit death signals, at least into myeloid cells. Strikingly, death induction by Siglecs is enhanced when cells are exposed to proinflammatory survival cytokines. Based on these recent insights, we hypothesize that at least some members of the Siglec family regulate immune responses via the activation of caspase-dependent and caspase-independent cell death pathways.

Effects of Delta12-prostaglandin J2 on bone regeneration and growth factor expression in rats

OBJECTIVES: Cyclopentenone prostaglandins have been shown to promote osteoblast differentiation in vitro. The aim of this study was to examine in a rat model the effects of local delivery of Delta(12)-prostaglandin J(2) (Delta(12)-PGJ(2)) on new bone formation and growth factor expression in (i) cortical defects and (ii) around titanium implants. MATERIAL AND METHODS: Standardized transcortical defects were prepared bilaterally in the femur of 28 male Wistar rats. Ten microliters of Delta(12)-PGJ(2) at 4 concentrations (10(-9), 10(-7), 10(-5) and 10(-3) mol/l) in a collagen vehicle were delivered inside a half-cylindrical titanium chamber fixed over the defect. Contralateral defects served as vehicle controls. Ten days after surgery, the amount of new bone formation in the cortical defect area was determined by histomorphometry and expression of platelet-derived growth factor (PDGF)-A and -B, insulin-like growth factor (IGF)-I/II, bone morphogenetic protein (BMP)-2 and -6 was examined by immunohistochemistry. In an additional six rats, 24 titanium implants were inserted into the femur. Five microliters of carboxymethylcellulose alone (control) or with Delta(12)-PGJ(2) (10(-5) and 10(-3) mol/l) were delivered into surgically prepared beds prior to implant installation. RESULTS: Delta(12)-PGJ(2) (10(-5) and 10(-3) mol/l) significantly enhanced new bone formation (33%, P<0.05) compared with control cortical defects. Delivery of Delta(12)-PGJ(2) at 10(-3) mol/l significantly increased PDGF-A and -B and BMP-2 and -6 protein expression (P<0.05) compared with control defects. No significant difference was found in IGF-I/II expression compared with controls. Administration of Delta(12)-PGJ(2) also significantly increased endosteal new bone formation around implants compared with controls. CONCLUSION: Local delivery of Delta(12)-PGJ(2) promoted new bone formation in the cortical defect area and around titanium implants. Enhanced expression of BMP-2 and -6 as well as PDGF-A and -B may be involved in Delta(12)-PGJ(2)-induced new bone formation.

Glycoprotein VI is a major collagen receptor for platelet activation: it recognizes the platelet-activating quaternary structure of collagen, whereas CD36, glycoprotein IIb/IIIa, and von Willebrand factor do not

Simple collagen-related peptides (CRPs) containing a repeat Gly-Pro-Hyp sequence are highly potent platelet agonists. Like collagen, they must exhibit tertiary (triple-helical) and quaternary (polymeric) structure to activate platelets. Platelet signaling events induced by the peptides are the same as most of those induced by collagen. The peptides do not recognize the alpha 2 beta 1 integrin. To identify the signaling receptor involved, we have evaluated the response to the CRP, Gly-Lys-Hyp(Gly-Pro-Hyp)10-Gly-Lys-Hyp-Gly of platelets with defined functional deficiencies. These studies exclude a primary recognition role for CD36, von Willebrand factor (vWF), or glycoprotein (GP) IIb/IIIa. Thus, both CD36 and vWF-deficient platelets exhibited normal aggregation, normal fibrinogen binding, and normal expression of CD62 and CD63, measured by flow cytometry, in response to the peptide, and there was normal expression of CD62 and CD63 on thrombasthenic platelets. In contrast, GPVI-deficient platelets were totally unresponsive to the peptide, indicating that this receptor recognizes the Gly-Pro-Hyp sequence in collagen. GPVI-deficient platelets showed some fibrinogen binding in response to collagen but failed to aggregate and to express CD62 and CD63. Collagen, but not CRP-XL, contains binding sites for alpha 2 beta 1. Therefore, it is possible that collagen still induces some signaling via alpha 2 beta 1, leading to activation of GPIIb/IIIa. Our findings are consistent with a two-site, two-step model of collagen interaction with platelets involving recognition of specific sequences in collagen by an adhesive receptor such as alpha 2 beta 1 to arrest platelets under flow and subsequent recognition of another specific collagen sequence by an activatory receptor, namely GPVI.

Autophagic-like cell death in neutrophils induced by autoantibodies

Human neutrophils undergo autophagic-like cell death following Sialic acid binding immunoglobulin-like lectin-9 (Siglec-9) ligation and concurrent stimulation with certain, but not all, neutrophil survival cytokines. Caspase inhibition by these cytokines is required, but is not sufficient, to trigger this particular form of cell death. Additional mechanisms may involve reactive oxygen species (ROS), and blocking of ROS or prevention of ROS production prevents autophagic-like neutrophil death. Interestingly, human intravenous immunoglobulin (IVIg) preparations contain natural anti-Siglec-9 autoantibodies, which are able to ligate Siglec-9 on neutrophils and induce autophagic-like cell death in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and some other survival cytokines. Here, we discuss the pathophysiological and therapeutic implications of these recent findings.

Deficiency of mannose-binding lectin-associated serine protease-2 associated with increased risk of fever and neutropenia in pediatric cancer patients

BACKGROUND: Mannose-binding lectin-associated serine protease-2 (MASP-2) is an essential component of the lectin pathway of complement activation. MASP-2 deficiency is common because of genetic polymorphisms, but its impact on susceptibility to infection is largely unknown. The aim of the present study was to determine whether children with cancer and MASP-2 deficiency develop more frequent or more severe episodes of fever and severe chemotherapy-induced neutropenia (FN). METHODS: Serum MASP-2 was measured by enzyme-linked immunosorbent assay at the time of diagnosis in children treated with chemotherapy for cancer. Association of FN episodes with MASP-2 concentration was analyzed using Poisson regression accounting for chemotherapy intensity and duration. RESULTS: Median MASP-2 in 94 children was 527 ng/mL (interquartile range, 367-686). Nine (10%) children had MASP-2 deficiency (<200 ng/mL). During a cumulative chemotherapy exposure time of 82 years, 177 FN episodes were recorded. MASP-2 deficient children had a significantly increased risk of developing FN (multivariate risk ratio, 2.08; 95% confidence interval, 1.31-3.21; P = 0.002), translating into significantly prolonged cumulative duration of hospitalization and of intravenous antimicrobial therapy. They experienced significantly more episodes of FN without a microbiologically defined etiology, and there was a trend toward more frequent episodes of FN with bacteremia. CONCLUSION: In this study, MASP-2 deficiency was associated with an increased risk of FN in children treated with chemotherapy for cancer. MASP-2 deficiency represents a novel risk factor for chemotherapy-related infections.

Nosocomial infection: A risk factor for a complicated course in children with respiratory syncytial virus infection - Results from a prospective multicenter German surveillance study

BACKGROUND: Nosocomially acquired respiratory syncytial virus infections (RSV-NI) may cause serious problems in hospitalized paediatric patients. Hitherto, prospectively collected representative data on RSV-NI from multicenter studies in Germany are limited. METHODS: The DMS RSV Ped database was designed for the prospective multicenter documentation and analysis of clinically relevant aspects of the management of inpatients with RSV-infection. The study covered six consecutive seasons (1999-2005); the surveillance took place in 14 paediatric hospitals in Germany. RESULTS: Of the 1568 prospectively documented RSV-infections, 6% (n=90) were NI and 94% (n=1478) were community acquired (CA). A significantly higher proportion in the NI group displayed additional risk factors like prematurity, chronic lung disease, mechanical ventilation (med. history), congenital heart disease, and neuromuscular impairment. Of all NI, 55% occurred in preterms (30.6% of all RSV-infections in preterms with severe chronic lung disease of prematurity were NI). Illness severity as well as the total mortality, but not the attributable mortality was significantly higher in the NI group. In the multivariate analysis, NI was significantly associated with the combined outcome 'complicated course of disease'. CONCLUSION: This is the first prospective multicenter study from Germany, which confirms the increased risk of a severe clinical course in nosocomially acquired RSV-infection. Of great concern is the high rate of (preventable) NI in preterms, in particular in those with severe chronic lung disease or with mechanical ventilation due to other reasons.

Prognosis in pediatric hematologic malignancies is associated with serum concentration of mannose-binding lectin-associated serine protease-2 (MASP-2)

BACKGROUND: Mannose-binding lectin (MBL) and MBL-associated serine protease-2 (MASP-2) are key components of the lectin pathway of complement activation. Their serum concentrations show a wide interindividual variability. This study investigated whether the concentration of MBL and MASP-2 is associated with prognosis in pediatric patients with cancer. METHODS: In this retrospective multicenter study, MBL and MASP-2 were measured by commercially available ELISA in frozen remnants of serum taken at diagnosis. Associations of overall survival (OS) and event-free survival (EFS) with MBL and MASP-2 were assessed by multivariate Cox regression accounting for prognostically relevant clinical variables. RESULTS: In the 372 patients studied, median serum concentration of MBL was 2,808 microg/L (range, 2-10,060) and 391 microg/L (46-2,771) for MASP-2. The estimated 4-year EFS was 0.60 (OS, 0.78). In the entire, heterogeneous sample, MBL and MASP-2 were not significantly associated with OS or EFS. In patients with hematologic malignancies, however, higher MASP-2 was associated with better EFS in a significant and clinically relevant way (hazard ratio per tenfold increase (HR), 0.22; 95% CI, 0.09-0.54; P = 0.001). This was due to patients with lymphoma (HR, 0.11; 95% CI, 0.03-0.47; P = 0.003), but less for those with acute leukemia (HR, 0.35; 95% CI, 0.11-1.15; P = 0.083). CONCLUSION: In this study, higher MASP-2 was associated with better EFS in pediatric patients with hematologic malignancies, especially lymphoma. Whether MASP-2 is an independent prognostic factor affecting risk stratification and anticancer therapy needs to be assessed in prospective, disease-specific studies.

Activation of the epidermal growth factor receptor (EGFR) by a novel metalloprotease pathway

Neutrophil Elastase (NE) is a pro-inflammatory protease present at higher than normal levels in the lung during inflammatory disease. NE regulates IL-8 production from airway epithelial cells and can activate both EGFR and TLR4. TACE/ADAM17 has been reported to trans-activate EGFR in response to NE. Here, using 16HBE14o-human bronchial epithelial cells we demonstrate a new mechanism by which NE regulates both of these events. A high molecular weight soluble metalloprotease activity detectable only in supernatants from NE-treated cells by gelatin and casein zymography was confirmed to be meprin alpha by Western immunoblotting. In vitro studies demonstrated the ability of NE to activate meprin alpha, which in turn could release soluble TGFalpha and induce IL-8 production from 16HBE14o- cells. These effects were abrogated by actinonin, a specific meprin inhibitor. NE-induced IL-8 expression was also inhibited by meprin alpha siRNA. Immunoprecipitation studies detected EGFR/TLR4 complexes in NE-stimulated cells overexpressing these receptors. Confocal studies confirmed colocalization of EGFR and TLR4 in 16HBE14o- cells stimulated with meprin alpha. NFkappaB was also activated via MyD88 in these cells by meprin alpha. In bronchoalveolar lavage fluid from NE knock-out mice infected intra-tracheally with Pseudomonas aeruginosa meprin alpha was significantly decreased compared with control mice, and was significantly increased and correlated with NE activity, in bronchoalveolar lavage fluid from individuals with cystic fibrosis but not healthy controls. The data describe a previously unidentified lung metalloprotease meprin alpha, and its role in NE-induced EGFR and TLR4 activation and IL-8 production.