Plexin-D1/Semaphorin 3E pathway may contribute to dysregulation of vascular tone control and defective angiogenesis in systemic sclerosis

Abstract

IntroductionThe 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.MethodsSema3E 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.ResultsSerum 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.ConclusionsOur 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.

Histone Deacetylase 5 Is Overexpressed in Scleroderma Endothelial Cells and Impairs Angiogenesis via Repression of Proangiogenic Factors

“…We first used ECs isolated from healthy subjects and from patients with SSc and performed a Matrigel tube formation assay. Similar to findings reported previously , SSc ECs, in the absence of an angiogenic stimulus, were unable to form tube‐like structures on Matrigel, whereas healthy donor ECs exhibited tube formation (Figure E). SSc ECs transfected with control siRNA also demonstrated a diminished capability to form tubes (Figure F).…”

“…The mechanism of dysregulated angiogenesis in SSc ECs appears to be multifactorial. These mechanistic factors include altered expression of angiogenic‐related proteins and transcription factors , impairment of the urokinase‐type plasminogen activator receptor pathway , defects in the basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) pathways , and changes in chemokine and chemokine receptor expression and signaling . In addition, SSc ECs can promote fibroblast activation via the CCN2/transforming growth factor β (TGFβ) pathway .…”

Protein-Coding Variants Implicate Novel Genes Related to Lipid Homeostasis Contributing to Body Fat Distribution

“…Mutations in this gene are associated with Moebius syndrome 102–105 , and persistent truncus arteriosus 99,106 . PLXND1 is involved in angiogenesis as part of the SEMA and VEGF signalling pathways 107–110 . PLXND1 was implicated in the development of T2D through its interaction with SEMA3E in mice.…”

Vascular Remodelling and Mesenchymal Transition in Systemic Sclerosis

“…Soluble moieties present in the blood of SSc patients activate and induce in the presence of neutrophils the programmed death via apoptosis of endothelial cells [ 16 ], suggesting that inflammatory leukocytes directly contribute to the endothelial injury [ 17 ]. The apoptosis of endothelial cells [ 3 ], the aberrant expression of transcription factors [ 18 – 20 ], of cytokines and of growth factors, specifically including the production of the antiangiogenic VEGF165b isoform of the vascular endothelial growth factor (VEGF) [ 21 ], alterations of pathways activated by the interaction of components of the class III semaphorin family and of their receptors, Plexin-D1 and Neuropilin-1 [ 22 , 23 ], and the defects of sprouting angiogenesis and vasculogenesis participate in the remodelling of the vasculature [ 24 ]. The events occurring at the cellular levels are poorly characterized.…”