Role of sialidase Neu3 and ganglioside GM3 in cardiac fibroblasts activation.

Cardiac fibrosis is a key physiological response to cardiac tissue injury to protect the heart from wall rupture. However, its progression increases heart stiffness, eventually causing a decrease in heart contractility. Unfortunately, to date, no efficient antifibrotic therapies are available to the clinic. This is primarily due to the complexity of the process, which involves several cell types and signaling pathways. For instance, the transforming growth factor beta (TGF-β) signaling pathway has been recognized to be vital for myofibroblasts activation and fibrosis progression. In this context, complex sphingolipids, such as ganglioside GM3, have been shown to be directly involved in TGF-β receptor 1 (TGF-R1) activation. In this work, we report that an induced up-regulation of sialidase Neu3, a glycohydrolytic enzyme involved in ganglioside cell homeostasis, can significantly reduce cardiac fibrosis in primary cultures of human cardiac fibroblasts by inhibiting the TGF-β signaling pathway, ultimately decreasing collagen I deposition. These results support the notion that modulating ganglioside GM3 cell content could represent a novel therapeutic approach for cardiac fibrosis, warranting for further investigations

Identification of New Hematopoietic Cell Subsets with a Polyclonal Antibody Library Specific for Neglected Proteins

The identification of new markers, the expression of which defines new phenotipically and functionally distinct cell subsets, is a main objective in cell biology. We have addressed the issue of identifying new cell specific markers with a reverse proteomic approach whereby approximately 1700 human open reading frames encoding proteins predicted to be transmembrane or secreted have been selected in silico for being poorly known, cloned and expressed in bacteria. These proteins have been purified and used to immunize mice with the aim of obtaining polyclonal antisera mostly specific for linear epitopes. Such a library, made of about 1600 different polyclonal antisera, has been obtained and screened by flow cytometry on cord blood derived CD34+CD45dim cells and on peripheral blood derived mature lymphocytes (PBLs). We identified three new proteins expressed by fractions of CD34+CD45dim cells and eight new proteins expressed by fractions of PBLs. Remarkably, we identified proteins the presence of which had not been demonstrated previously by transcriptomic analysis. From the functional point of view, looking at new proteins expressed on CD34+CD45dim cells, we identified one cell surface protein (MOSC-1) the expression of which on a minority of CD34+ progenitors marks those CD34+CD45dim cells that will go toward monocyte/granulocyte differentiation. In conclusion, we show a new way of looking at the membranome by assessing expression of generally neglected proteins with a library of polyclonal antisera, and in so doing we have identified new potential subsets of hematopoietic progenitors and of mature PBLs

Sphingolipids and Atherosclerosis: The Dual Role of Ceramide and Sphingosine-1-Phosphate

Sphingolipids are bioactive molecules that play either pro- and anti-atherogenic roles in the formation and maturation of atherosclerotic plaques. Among SLs, ceramide and sphingosine-1-phosphate showed antithetic properties in regulating various molecular mechanisms and have emerged as novel potential targets for regulating the development of atherosclerosis. In particular, maintaining the balance of the so-called ceramide/S1P rheostat is important to prevent the occurrence of endothelial dysfunction, which is the trigger for the entire atherosclerotic process and is strongly associated with increased oxidative stress. In addition, these two sphingolipids, together with many other sphingolipid mediators, are directly involved in the progression of atherogenesis and the formation of atherosclerotic plaques by promoting the oxidation of low-density lipoproteins (LDL) and influencing the vascular smooth muscle cell phenotype. The modulation of ceramide and S1P levels may therefore allow the development of new antioxidant therapies that can prevent or at least impair the onset of atherogenesis, which would ultimately improve the quality of life of patients with coronary artery disease and significantly reduce their mortality

Alterations of the Sialylation Machinery in Brugada Syndrome

Brugada Syndrome (BrS) is an inherited arrhythmogenic disorder with an increased risk of sudden cardiac death. Recent evidence suggests that BrS should be considered as an oligogenic or polygenic condition. Mutations in genes associated with BrS are found in about one-third of patients and they mainly disrupt the cardiac sodium channel NaV1.5, which is considered the main cause of the disease. However, voltage-gated channel’s activity could be impacted by post-translational modifications such as sialylation, but their role in BrS remains unknown. Thus, we analyzed high risk BrS patients (n = 42) and healthy controls (n = 42) to assess an involvement of sialylation in BrS. Significant alterations in gene expression and protein sialylation were detected in Peripheral Blood Mononuclear Cells (PBMCs) from BrS patients. These changes were significantly associated with the phenotypic expression of the disease, as the size of the arrhythmogenic substrate and the duration of epicardial electrical abnormalities. Moreover, protein desialylation caused a reduction in the sodium current in an in vitro NaV1.5-overexpressing model. Dysregulation of the sialylation machinery provides definitive evidence that BrS affects extracardiac tissues, suggesting an underlying cause of the disease. Moreover, detection of these changes at the systemic level and their correlation with the clinical phenotype hint at the existence of a biomarker signature for BrS

Additional file 1: Figure S1. of Effects of the pulsed electromagnetic field PSTÂŽ on human tendon stem cells: a controlled laboratory study

Phenotypic characterization of human dermal fibroblasts (hDFs) and human tendon stem cells (hTSCs) by flow cytometry. (PDF 339 kb

Comparison of the results obtained with antisera specific for well-known proteins assessed both by FACS on PBMCs from healthy donors and by IHC on inflamed lymph nodes.

<p>Comparison of the results obtained with antisera specific for well-known proteins assessed both by FACS on PBMCs from healthy donors and by IHC on inflamed lymph nodes.</p

FACS analysis with sera specific for well-known proteins.

<p>(A) Comparison of the CD8 staining performed on PBL with either a commercially available anti CD8 mAb (BD biosciences) or the anti CD8 alpha antiserum at 1∶100 dilution points. Both the samples were stained also with commercially available anti CD3 and anti CD4 mAb (BD biosciences). The distribution of CD4 and CD8 is analyzed upon gating on CD3 positive cells. (B) Examples of staining with antisera from the library. PBLs from healthy donors were stained with anti CD2, CD1d, CD8 alpha, CD25, CD72, CD80, CD38, and CD86. The expression of CD25 was assessed upon a 24 hours activation of PBLs with 1 µg/ml of PHA. The expression of CD80 and CD86 was assessed upon gating on monocytes after a 24 hours activation of PBLs with 1 µg/ml of PHA. The expression of CD133 was analyzed on cord blood derived CD34+, CD45dim cells. Serum from not immunized mice was used as negative control in all the stainings.</p

Schematic representation of the antisera library generation.

<p>Schematic representation of the antisera library generation.</p

Results of sera screening by FACS on PBL and Cord Blood cells.

<p>(A) FACS analysis of sera positive on PBLs. PBLs were stained with the indicated sera at the optimal dilution point (1∶50 to 1∶200). The samples were stained also with anti CD3, anti CD19 and anti CD56 mAbs to analyze the sera reactivity upon gating on the different subpopulations. A plot representative of five different donors is shown for each serum. (B) KRTCAP-3 specific serum recognizes PHA-treated cells. PBMCs are treated for 24 hours with 1 µg/ml of PHA. After the treatment both un-stimulated and treated cells are stained with the KRTCAP-3-specific serum. (C) FACS analysis of sera positive on cord blood cells. Cord blood mononuclear cells are stained with the indicated sera at the optimal concentration (1∶50 to 1∶100). The samples are stained also with anti CD45 and anti CD34 mAbs to perform the analysis upon gating on CD34highCD45dim. A plot representative of a least 3 independent donors is shown. Il all the cases (A,B,C,) a staining with the serum of not immunized mice was used as negative control. (D) RT-PCR analysis. a- cDNA from total PBMC were amplified with primers specific for the indicated proteins. b- cDNA from both un-stimulated and PHA-treated PBMC was amplified with KRTCAP-3 specific primers. KRTCAP3 expression is up regulated two to three times. Beta actin amplification is used as normalization. c- cDNA samples from CD34+CD45dim cells were generated by retro-transcription of RNA extracted from a pool of CD34 positive cells from 2–3 independent cord blood units magnetically purified using the Miltenyi CD34 microbeads kit according the manufacturer instruction. The purity of the CD34+CD45dim cells was usually >99%. The samples were amplified with primers specific for the indicated proteins and described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034395#s2" target="_blank">Methods</a> section.</p