Research Center for Experimental Medicine

Sant'Ambrogio di Torino, Italy

Research Center for Experimental Medicine

Sant'Ambrogio di Torino, Italy
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Boot A.M.,University of Groningen | Lumbroso S.,University of Nimes | Lumbroso S.,Universites Of Montpellier 1 Et 2 | Verhoef-Post M.,Erasmus Medical Center | And 7 more authors.
Journal of Clinical Endocrinology and Metabolism | Year: 2011

Context: Germline and somatic activating mutations in the LH receptor (LHR) gene have been reported. Objective: Our objective was to perform mutation analysis of the LHR gene of patients with Leydig cell adenoma or hyperplasia. Functional studies were conducted to compare the D578H-LHR mutant with the wild-type (WT)-LHR and the D578G-LHR mutant, a classic cause of testotoxicosis. The three main signal transduction pathways in which LHR is involved were studied. Patients: We describe eight male patients with gonadotropin-independent precocious puberty due to Leydig cell adenoma or hyperplasia. Results: The D578H-LHR mutation was found in the adenoma or nodule with hyperplasia in all but two patients. D578H-LHR displayed a constitutively increased but noninducible production of cAMP, led to a very high production of inositol phosphates, and induced a slight phosphorylation of p44/42 MAPK in the absence of human chorionic gonadotropin. The D578G-LHR showed a response intermediate between WT-LHR and the D578H-LHR. Subcellular localization studies showed that the WT-LHR was almost exclusively located at the cell membrane, whereas the D578HLHR showed signs of internalization. D578H-LHR was the only receptor to colocalize with early endosomes in the absence of human chorionic gonadotropin. Conclusions: Although several LHR mutations have been reported in testotoxicosis, the D578H-LHR mutation, which has been found only as a somatic mutation, appears up untilnowto be specifically responsible for Leydig cell adenomas. This is reflected by the different activation of the signal transduction pathways, when compared with the WT-LHR or D578G-LHR, which may explain the tumorigenesis in the D578H mutant. Copyright © 2011 by The Endocrine Society Printed in U.S.A.

Saborit-Villarroya I.,University of Turin | Vaisitti T.,University of Turin | Vaisitti T.,Human Genetics Foundation HuGeF | Rossi D.,University of Piemonte Orientale | And 6 more authors.
Leukemia | Year: 2011

CD38, a nucleotide-metabolizing ectoenzyme and a receptor, is a negative prognostic marker for chronic lymphocytic leukemia (CLL) patients. CD38 has a genetic polymorphism, with a C G variation in a putative E-box located in a regulatory region. E2A, the predominant E-box factor in B lymphocytes, was found to be highly expressed by CD38 CLL patients. The highest CD38 levels scored by E2A /G carrier patients suggested that E2A is (i) directly associated with CD38 expression, and that (ii) the binding of the transcription factor is influenced by the CD38 genotype. Chromatin immunoprecipitation indicated that E2A directly interacts with the CD38 regulatory region. Furthermore, E2A binding was stronger in the presence of the G allele. Experiments of E2A silencing led to a significant reduction of surface levels of CD38, confirming the working hypothesis. A direct functional interplay between E2A and CD38 was shown by exposing CLL cells to interleukin-2 and TLR-9 ligands, both inducers of CD38 expression. Under these conditions, CD38 upregulation was primarily conditioned by the presence of E2A and then by the G allele. The results of this study link E2A and CD38 expression within a common pathway, in which E-protein activity is required for the efficient induction of CD38 transcription. © 2011 Macmillan Publishers Limited All rights.

Herrera M.B.,Research Center for Experimental Medicine | Herrera M.B.,Sister Spa | Fonsato V.,Research Center for Experimental Medicine | Gatti S.,The Surgical Center | And 8 more authors.
Journal of Cellular and Molecular Medicine | Year: 2010

Several studies indicate that adult stem cells may improve the recovery from acute tissue injury. It has been suggested that they may contribute to tissue regeneration by the release of paracrine factors promoting proliferation of tissue resident cells. However, the factors involved remain unknown. In the present study we found that microvesicles (MVs) derived from human liver stem cells (HLSC) induced in vitro proliferation and apoptosis resistance of human and rat hepatocytes. These effects required internalization of MVs in the hepatocytes by an α4-integrin-dependent mechanism. However, MVs pre-treated with RNase, even if internalized, were unable to induce hepatocyte proliferation and apoptosis resistance, suggesting an RNA-dependent effect. Microarray analysis and quantitative RT-PCR demonstrated that MVs were shuttling a specific subset of cellular mRNA, such as mRNA associated in the control of transcription, translation, proliferation and apoptosis. When administered in vivo, MVs accelerated the morphological and functional recovery of liver in a model of 70% hepatectomy in rats. This effect was associated with increase in hepatocyte proliferation and was abolished by RNase pre-treatment of MVs. Using human AGO2, as a reporter gene present in MVs, we found the expression of human AGO2 mRNA and protein in the liver of hepatectomized rats treated with MVs. These data suggested a translation of the MV shuttled mRNA into hepatocytes of treated rats. In conclusion, these results suggest that MVs derived from HLSC may activate a proliferative program in remnant hepatocytes after hepatectomy by a horizontal transfer of specific mRNA subsets. © 2009 The Authors Journal compilation © 2010 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

Ranghino A.,Research Center for Experimental Medicine | Cantaluppi V.,Research Center for Experimental Medicine | Grange C.,Research Center for Experimental Medicine | Vitillo L.,Research Center for Experimental Medicine | And 6 more authors.
International Journal of Immunopathology and Pharmacology | Year: 2012

Paracrine mediators released from endothelial progenitor cells (EPCs) have been implicated in neoangiogenesis following ischemia. Recently, we demonstrated that microvesicles (MVs) derived from EPCs are able to activate an angiogenic program in quiescent endothelial cells by a horizontal transfer of RNA. In this study we aim to investigate whether EPC-derived MVs are able to induce neoangiogenesis and to enhance recovery in a murine model of hindlimb ischemia. Hindlimb ischemia was induced in severe combined immunodeficient (SCID) mice by ligation and resection of the left femoral artery and mice were treated with EPC-derived MVs (MVs), RNase-inactivated MVs (RnaseMVs), fibroblast-derived MVs or vehicle alone as control (CTL). Since MVs contained the angiogenic miR-126 and miR-296, we evaluated whether microRNAs may account for the angiogenic activities by treating mice with MVs obtained from DICER-knock-down EPC (DICER-MVs). The limb perfusion evaluated by laserdoppler analysis demonstrated that MVs significantly enhanced perfusion in respect to CTL (0.50±0.08 vs 0.39±0.03, p < 0.05). After 7 days, immunohistochemical analyses on the gastrocnemius muscle of the ischemic hindlimb showed that MVs but not fibroblast-MVs significantly increased the capillary density in respect to CTL (MVs vs CTL: 24.7±10.3 vs 13.5±6, p < 0.0001) and (fibroblast-MVs vs CTL: 10.2±3.4 vs 13.5±6, ns); RNaseMVs and DICER-MVs significantly reduced the effect of MVs (RNaseMVs vs CTL: 15.7±4.1 vs 13.5±6, ns) (MVs vs DICER-MVs 24.7±10.3 vs 18.1±5.8, p < 0.05), suggesting a role of RNAs shuttled by MVs. Morphometric analysis confirmed that MVs enhanced limb perfusion and reduced injury. The results of the present study indicate that treatment with EPC-derived MVs improves neovascularization and favors regeneration in severe hindlimb ischemia induced in SCID mice. This suggests a possible use of EPCs-derived MVs for treatment of peripheral arterial disease. Copyright © by BIOLIFE, s.a.s.

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