title: Plexin-D1/Semaphorin 3E pathway may contribute to dysregulation of vascular tone control and defective angiogenesis in systemic sclerosis.
abstract: BACKGROUND
  The vascular and nervous systems have several anatomic and molecular mechanism similarities. Emerging evidence suggests that proteins involved in transmitting axonal guidance cues, including members of class III semaphorin (Sema3) family, play a critical role in blood vessel guidance during physiological and pathological vascular development. Sema3E is a natural antiangiogenic molecule that causes filopodial retraction in endothelial cells, inhibiting cell adhesion by disrupting integrin-mediated adhesive structures. The aim of the present study was to investigate whether in systemic sclerosis (SSc) Plexin-D1/Sema3E axis could be involved in the dysregulation of vascular tone control and angiogenesis.
  
  
  METHODS
  Sema3E levels were measured by quantitative colorimetric sandwich ELISA in serum samples from 48 SSc patients, 45 subjects with primary Raynaud's phenomenon (pRP) and 48 age-matched and sex-matched healthy controls. Immunofluorescence staining on skin sections from 14 SSc patients and 12 healthy subjects was performed to evaluate Sema3E and Plexin-D1 expression. Western blotting was used to assess Plexin-D1/Sema3E axis in human SSc and healthy dermal microvascular endothelial cells (SSc-MVECs and H-MVECs, respectively) at basal condition and after stimulation with recombinant human vascular endothelial growth factor (VEGF), SSc and healthy sera. Capillary morphogenesis on Matrigel was performed on H-MVECs treated with healthy, pRP or SSc sera in the presence of Sema3E and Plexin-D1 soluble peptides.
  
  
  RESULTS
  Serum Sema3E levels were significantly higher both in pRP subjects and SSc patients than in controls. In SSc, Sema3E levels were significantly increased in patients with early nailfold videocapillaroscopy (NVC) pattern compared to active/late patterns and pRP, and in patients without digital ulcers versus those with ulcers. In SSc skin, Sema3E expression was strongly increased in the microvascular endothelium. Cultured SSc-MVECs showed higher levels of phosphorylated Plexin-D1 and Sema3E expression than H-MVECs, and stimulation with SSc sera increased phosphorylated Plexin-D1 and Sema3E in H-MVECs. The addition of Sema3E-binding Plexin-D1 soluble peptide significantly attenuated the antiangiogenic effect of SSc sera on H-MVECs.
  
  
  CONCLUSIONS
  Our findings suggest that Plexin-D1/Sema3E axis is triggered in SSc endothelium and may have a role in the dysregulation of angiogenesis and vascular tone control by inducing neuro-vascular mechanism alterations clinically evident in particular in the early disease phases.
authors: Department of Experimental and Clinical Medicine, Division of Rheumatology, Azienda Ospedaliero-Universitaria Careggi (AOUC), University of Florence, Viale Pieraccini 18, I-50139, Florence, Italy. celestina.mazzotta@unifi.it.
authors: Celestina
authors: C
authors: Mazzotta
authors: Department of Experimental and Clinical Medicine, Division of Rheumatology, Azienda Ospedaliero-Universitaria Careggi (AOUC), University of Florence, Viale Pieraccini 18, I-50139, Florence, Italy. eloisaromano@libero.it.
authors: Eloisa
authors: E
authors: Romano
authors: Department of Experimental and Clinical Medicine, Division of Rheumatology, Azienda Ospedaliero-Universitaria Careggi (AOUC), University of Florence, Viale Pieraccini 18, I-50139, Florence, Italy. cosimobruni85@gmail.com.
authors: Cosimo
authors: C
authors: Bruni
authors: Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, University of Florence, Largo Brambilla 3, I-50134, Florence, Italy. mirkomanetti@yahoo.it.
authors: Mirko
authors: M
authors: Manetti
authors: Department of Experimental and Clinical Medicine, Division of Rheumatology, Azienda Ospedaliero-Universitaria Careggi (AOUC), University of Florence, Viale Pieraccini 18, I-50139, Florence, Italy. lepri.gemma@gmail.com.
authors: Gemma
authors: G
authors: Lepri
authors: Department of Experimental and Clinical Medicine, Division of Rheumatology, Azienda Ospedaliero-Universitaria Careggi (AOUC), University of Florence, Viale Pieraccini 18, I-50139, Florence, Italy. s.bellandorandone@gmail.com.
authors: Silvia
authors: S
authors: Bellando-Randone
authors: Department of Experimental and Clinical Medicine, Division of Rheumatology, Azienda Ospedaliero-Universitaria Careggi (AOUC), University of Florence, Viale Pieraccini 18, I-50139, Florence, Italy. jelena308@hotmail.com.
authors: Jelena
authors: J
authors: Blagojevic
authors: Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, University of Florence, Largo Brambilla 3, I-50134, Florence, Italy. lidia.ibba@unifi.it.
authors: Lidia
authors: L
authors: Ibba-Manneschi
authors: Department of Experimental and Clinical Medicine, Division of Rheumatology, Azienda Ospedaliero-Universitaria Careggi (AOUC), University of Florence, Viale Pieraccini 18, I-50139, Florence, Italy. cerinic@unifi.it.
authors: Marco
authors: M
authors: Matucci-Cerinic
authors: Department of Experimental and Clinical Medicine, Division of Rheumatology, Azienda Ospedaliero-Universitaria Careggi (AOUC), University of Florence, Viale Pieraccini 18, I-50139, Florence, Italy. s.guiducci@hotmail.com.
authors: Serena
authors: S
authors: Guiducci
mesh_terms: D000328:Adult; D000368:Aged; D001808:Blood Vessels / Q000378:metabolism* / Q000503:physiopathology; D015153:Blotting, Western; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008562:Membrane Glycoproteins; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000378:metabolism* / Q000503:physiopathology; D010766:Phosphorylation; D011928:Raynaud Disease / Q000378:metabolism / Q000503:physiopathology; D012595:Scleroderma, Systemic / Q000378:metabolism* / Q000503:physiopathology; D039961:Semaphorins / Q000097:blood / Q000378:metabolism*; D015398:Signal Transduction; D012867:Skin / Q000098:blood supply / Q000378:metabolism / Q000473:pathology
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; C493082:PLXND1 protein, human; C494123:SEMA3E protein, human; D039961:Semaphorins