Increased Levels of Leukocyte-Derived MMP-9 in Patients with Stable Angina Pectoris

Objective: There is a growing interest for matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in plasma as novel biomarkers in coronary artery disease (CAD). We aimed to identify the sources of MMP-8, MMP-9, TIMP-1 and TIMP-2 among peripheral blood cells and further explore whether gene expression or protein release was altered in patients with stable angina pectoris (SA). Methods: In total, plasma MMP-9 was measured in 44 SA patients and 47 healthy controls. From 10 patients and 10 controls, peripheral blood mononuclear cells (PBMC) and neutrophils were isolated and stimulated ex vivo. MMPs, TIMPs and myeloperoxidase were measured in plasma and supernatants by ELISA. The corresponding gene expression was measured by real-time PCR. Results: Neutrophils were the dominant source of MMP-8 and MMP-9. Upon moderate stimulation with IL-8, the neutrophil release of MMP-9 was higher in the SA patients compared with controls (p,0.05). In PBMC, the TIMP-1 and MMP-9 mRNA expression was higher in SA patients compared with controls, p,0.01 and 0.05, respectively. There were no differences in plasma levels between patients and controls except for TIMP-2, which was lower in patients, p,0.01. Conclusion: Measurements of MMPs and TIMPs in plasma may be of limited use. Despite similar plasma levels in SA patients and controls, the leukocyte-derived MMP-9 and TIMP-1 are significantly altered in patients. The findings indicate that th

Junín Virus Infection of Human Hematopoietic Progenitors Impairs In Vitro Proplatelet Formation and Platelet Release via a Bystander Effect Involving Type I IFN Signaling

Argentine hemorrhagic fever (AHF) is an endemo-epidemic disease caused by Junín virus (JUNV), a member of the arenaviridae family. Although a recently introduced live attenuated vaccine has proven to be effective, AHF remains a potentially lethal infection. Like in other viral hemorrhagic fevers (VHF), AHF patients present with fever and hemorrhagic complications. Although the causes of the bleeding are poorly understood, impaired hemostasis, endothelial cell dysfunction and low platelet counts have been described. Thrombocytopenia is a common feature in VHF syndromes, and it is a major sign for its diagnosis. However, the underlying pathogenic mechanism has not yet been elucidated. We hypothesized that thrombocytopenia results from a viral-triggered alteration of the megakaryo/thrombopoiesis process. Therefore, we evaluated the impact of JUNV on megakaryopoiesis using an in vitro model of human CD34+ cells stimulated with thrombopoietin. Our results showed that CD34+ cells are infected with JUNV in a restricted fashion. Infection was transferrin receptor 1 (TfR1)-dependent and the surface expression of TfR1 was higher in infected cultures, suggesting a novel arenaviral dissemination strategy in hematopoietic progenitor cells. Although proliferation, survival, and commitment in JUNV-infected cultures were normal, viral infection impaired thrombopoiesis by decreasing in vitro proplatelet formation, platelet release, and P-selectin externalization via a bystander effect. The decrease in platelet release was also TfR1-dependent, mimicked by poly(I:C), and type I interferon (IFN α/β) was implicated as a key paracrine mediator. Among the relevant molecules studied, only the transcription factor NF-E2 showed a moderate decrease in expression in megakaryocytes from either infected cultures or after type I IFN treatment. Moreover, type I IFN-treated megakaryocytes presented ultrastructural abnormalities resembling the reported thrombocytopenic NF-E2−/− mouse phenotype. Our study introduces a potential mechanism for thrombocytopenia in VHF and other diseases associated with increased bone marrow type I IFN levels

Spontaneous coronary artery dissection and its association with heritable connective tissue disorders

Objective: Spontaneous coronary artery dissection (SCAD) is an under-recognised but important cause of myocardial infarction and sudden cardiac death. We sought to determine the role of medical and molecular genetic screening for connective tissue disorders in patients with SCAD.Methods: We performed a single-centre retrospective descriptive analysis of patients with spontaneous coronary artery disease who had undergone medical genetics evaluation 1984-2014 (n=116). The presence or absence of traits suggestive of heritable connective tissue disease was extracted. Genetic testing for connective tissue disorders and/or aortopathies, if performed, is also reported.Results: Of the 116 patients (mean age 44.2 years, 94.8% women and 41.4% with non-coronary fibromuscular dysplasia (FMD)), 59 patients underwent genetic testing, of whom 3 (5.1%) received a diagnosis of connective tissue disorder: a 50-year-old man with Marfan syndrome; a 43-year-old woman with vascular Ehlers-Danlos syndrome and FMD; and a 45-year-old woman with vascular Ehlers-Danlos syndrome. An additional 12 patients (20.3%) had variants of unknown significance, none of which was thought to be a definite disease-causing mutation based on in silico analyses.Conclusions: Only a minority of patients with SCAD who undergo genetic evaluation have a likely pathogenic mutation identified on gene panel testing. Even fewer exhibit clinical features of connective tissue disorder. These findings underscore the need for further studies to elucidate the molecular mechanisms of SCAD

Acidic preconditioning improves the proangiogenic responses of endothelial colony forming cells

Objective: Acidosis is present in several pathological conditions where vasculogenesis takes place including ischemia, tumor growth and wound healing. We have previously demonstrated that acidosis induces human CD34+ cell apoptosis. Considering that endothelial colony-forming cells (ECFC) are a subpopulation of CD34+ cells and key players in vasculogenesis, in the present study we investigated the effect of acidosis on the survival and functionality of ECFC. Approach and results: Endothelial colony-forming cells obtained by differentiation of human cord blood CD34+ cells in endothelial growth medium-2 for 14–21 days were exposed at pH 7.4, 7.0 or 6.6. We found that acidosis failed to induce ECFC apoptosis and, although an early reduction in proliferation, chemotaxis, wound healing and capillary-like tubule formation was observed, once the medium pH was restored to 7.4, ECFC proliferation and tubulogenesis were augmented. Stromal cell derived factor-1 (SDF1)-driven migration and chemokine receptor type 4 surface expression were also increased. The maximal proangiogenic effect exerted by acidic preconditioning was observed after 6 h at pH 6.6. Furthermore, preconditioned ECFC showed an increased ability to promote tissue revascularization in a murine model of hind limb ischemia. Immunoblotting assays showed that acidosis activated AKT and ERK1/2 and inhibited p38 pathways. Proliferation rises triggered by acidic preconditioning were no longer observed after AKT or ERK1/2 inhibition, whereas p38 suppression not only mimicked but also potentiated the effect of acidosis on ECFC tubule formation abilities. Conclusions: These results demonstrate that acidic preconditioning greatly increases ECFC-mediated angiogenesis in vitro including ECFC proliferation, tubulogenesis and SDF1-driven chemotaxis and is a positive regulator of microvessel formation in vivo.Fil: Mena, Hebe Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Lokajczyk, Anna. Université Paris Descartes; Francia. Inserm; FranciaFil: Dizier, Blandine. Inserm; FranciaFil: Strier, Sergio E.. Ciudad Autónoma de Buenos Aires. Hospital "Bernardino Rivadavia"; ArgentinaFil: Voto, Liliana S.. Ciudad Autónoma de Buenos Aires. Hospital "Juan A. Fernández"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Boisson Vidal, Catherine. Université Paris Descartes; Francia. Inserm; FranciaFil: Schattner, Mirta Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Negrotto, Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

Sorghum Transformation: Overview and Utility

Over the past decade genomics resources available for sorghum have rapidly expanded (Paterson Int J Plant Genomics 2008:6, 2008), these resources, coupled with the recent completion of the genome sequence which is relatively small in size (730 Mb) (Paterson et al. Nature 457:551–556, 2009) makes sorghum a rather attractive species to study. Moreover, the USDA germplasm system maintains 42,614 accessions, of which more than 800 exotic landraces have been converted to day length-insensitive lines to facilitate their use in breeding programs. In addition, a set of EMS mutation stocks developed by the USDA Plant Stress and Germplasm Development Unit in Lubbock, TX (Xin et al. Bioenerg Res 2:10–16, 2009) will be a valuable resource for functional genomics studies in sorghum. However, in order to be a robust system for study a suite of functional genomics tools are necessary to complement these other resources to aid in down-stream hypothesis testing. A key functional genomics tool is the ability to modulate gene expression through the introduction of transgenic genetic elements. This is exemplified by recent work (Cook et al. Plant Cell 22:867–887, 2010) in which RNAi experiments were employed to specifically reduced expression of two alkylresorcinol synthases to demonstrate their role in the synthesis of the allelopathic molecule sorgoleone. In addition to its value as a functional genomics tool, plant transformation offers a route to broaden access to novel input and output traits for sorghum breeding programs