Neuropilins 1 and 2 mediate neointimal hyperplasia and re-endothelialization following arterial injury

Abstract

AimsNeuropilins 1 and 2 (NRP1 and NRP2) play crucial roles in endothelial cell migration contributing to angiogenesis and vascular development. Both NRPs are also expressed by cultured vascular smooth muscle cells (VSMCs) and are implicated in VSMC migration stimulated by PDGF-BB, but it is unknown whether NRPs are relevant for VSMC function in vivo. We investigated the role of NRPs in the rat carotid balloon injury model, in which endothelial denudation and arterial stretch induce neointimal hyperplasia involving VSMC migration and proliferation.Methods and resultsNRP1 and NRP2 mRNAs and proteins increased significantly following arterial injury, and immunofluorescent staining revealed neointimal NRP expression. Down-regulation of NRP1 and NRP2 using shRNA significantly reduced neointimal hyperplasia following injury. Furthermore, inhibition of NRP1 by adenovirally overexpressing a loss-of-function NRP1 mutant lacking the cytoplasmic domain (ΔC) reduced neointimal hyperplasia, whereas wild-type (WT) NRP1 had no effect. NRP-targeted shRNAs impaired, while overexpression of NRP1 WT and NRP1 ΔC enhanced, arterial re-endothelialization 14 days after injury. Knockdown of either NRP1 or NRP2 inhibited PDGF-BB-induced rat VSMC migration, whereas knockdown of NRP2, but not NRP1, reduced proliferation of cultured rat VSMC and neointimal VSMC in vivo. NRP knockdown also reduced the phosphorylation of PDGFα and PDGFβ receptors in rat VSMC, which mediate VSMC migration and proliferation.ConclusionNRP1 and NRP2 play important roles in the regulation of neointimal hyperplasia in vivo by modulating VSMC migration (via NRP1 and NRP2) and proliferation (via NRP2), independently of the role of NRPs in re-endothelialization.

Neuropilin 1 binds PDGF-D and is a co-receptor in PDGF-D–PDGFRβ signaling

“…Similar mechanisms have been described for PDGFRβ (Hellberg et al, 2009;Karlsson et al, 2006), and NRP1, as well as NRP2, has been suggested to be involved in PDGFR downstream signal conduction (Pellet-Many et al, 2015). Our initial analysis did, however, not reveal changes in PDGF-D-PDGFRβ downstream signaling dependent on the presence or absence of NRP1.…”

“…Despite reports of NRP1 interaction with PDGFs (Ball et al, 2010;Banerjee et al, 2006;Cao et al, 2010;Pellet-Many et al, 2011), a specific binding site for PDGFs in NRP1 is not known. In addition, interactions of NRP1 with PDGFRα or PDGFRβ have been suggested (Pellet-Many et al, 2015), but its potential role in PDGF-PDGFR signaling remains elusive.…”

Neuropilin 1 mediates epicardial activation and revascularization in the regenerating zebrafish heart

“…Activation of the epicardium and subsequent regeneration involves multiple cellular processes, including cell migration, proliferation, and EMT. It is well established that NRP1 modulates cell migration in diverse mammalian cell types (29, [54][55][56][57]. The conclusion that nrp1a is important for zebrafish epicardial migration is supported by our finding that ex vivo outgrowth from epicardial explants of nrp1a sa1485/sa1485 hearts was also impaired.…”

Emerging Roles for Neuropilin-2 in Cardiovascular Disease

“…NRPs were first implicated in neuronal guidance, vasculogenesis and angiogenesis in the embryo via mediating signalling pathways driven by class 3 Semaphorins (SEMA3s) and Vascular Endothelial Growth Factor (VEGF), respectively [ 25 , 29 , 30 , 31 , 32 ]. However, NRPs are now known to partner with a wide variety of transmembrane receptors and therefore modulate numerous signalling pathways [ 23 , 24 ], including those activated by Epidermal Growth Factor (EGF) [ 33 ], Fibroblast Growth Factor (FGF) [ 34 ], Hepatocyte Growth Factor (HGF) [ 35 ], Insulin-like Growth Factor (IGF) [ 36 ], Platelet-Derived Growth Factor (PDGF) [ 37 , 38 ] and Transforming Growth Factor beta (TGFβ) [ 39 ]. As a result, NRPs mediate multiple cellular processes, and dysregulation of their activity has been implicated with several pathological conditions [ 23 , 38 , 40 , 41 , 42 ].…”

“…However, NRPs are now known to partner with a wide variety of transmembrane receptors and therefore modulate numerous signalling pathways [ 23 , 24 ], including those activated by Epidermal Growth Factor (EGF) [ 33 ], Fibroblast Growth Factor (FGF) [ 34 ], Hepatocyte Growth Factor (HGF) [ 35 ], Insulin-like Growth Factor (IGF) [ 36 ], Platelet-Derived Growth Factor (PDGF) [ 37 , 38 ] and Transforming Growth Factor beta (TGFβ) [ 39 ]. As a result, NRPs mediate multiple cellular processes, and dysregulation of their activity has been implicated with several pathological conditions [ 23 , 38 , 40 , 41 , 42 ]. NRPs are expressed by ECs [ 31 ], leukocytes [ 24 ] and VSMCs [ 38 , 40 , 43 , 44 , 45 ] within the vasculature, and are emerging as multifaceted regulators of signalling pathways associated with CVD [ 23 ].…”