Exploring the Role of Hypusine Signaling in Vascular Smooth Muscle Cells for Mitigating Restenosis in Coronary Artery Disease.
BackgroundPost-surgical restenosis in patients with coronary artery disease (CAD) is a pathological vascular remodeling process characterized by neointimal hyperplasia, mainly driven by vascular smooth muscle cells (VSMCs) phenotypic switching toward synthetic and proliferative state. This study identifies novel signaling pathway promoting pro-proliferative phenotype of VSMC and contributing to the neointimal hyperplasia development. MethodsThe expression of hypusine signaling components was evaluated in human primary culture of coronary artery smooth muscle cells (CoASMCs) isolated from controls and patients with CAD, using comparative proteomic analysis and western blotting, as well as in three preclinical animal models of restenosis; rat carotid injury, mice carotid ligation and canine coronary artery bypass graft. CAD-CoASMCs proliferation was assessed by western blot and immunofluorescence with pharmacological (GC7) and molecular (shRNA) inhibitors of deoxyhypusine synthase (DHPS). The contribution of hypusine signaling to neointimal hyperplasia was investigated using both pharmacological and smooth muscle cell-specific knockout mice approaches. Additionally, human saphenous vein and human coronary artery tissue cultures were employed to explore the translational potential of targeting hypusine signaling to prevent neointimal hyperplasia. ResultsAll components of the hypusine pathway (eukaryote translational initiation factor 5A (eIF5A), deoxyhypusine hydroxylase (DOHH) and DHPS) were significantly overexpressed in CAD-CoASMCs and in preclinical animal models of restenosis. Pharmacological and molecular inhibition of DHPS reduced eIF5A hypusination, VSMC proliferation and expression of extracellular matrix proteins. Proteomic and KEGG analyses demonstrated disruption of cell cycle and DNA replication pathways, including a downregulation of threonine tyrosine kinase (TTK). Our findings suggest that TTK acts as a downstream effector of hypusine signaling, partly mediating to the proliferative effects observed in CAD-CoASMCs. In vivo, pharmacological and genetic inhibition of DHPS significantly reduced neointimal hyperplasia without adverse effects. Finally, ex vivo human tissue culture confirmed that GC7 mitigates growth factor-induced vascular remodeling. ConclusionsHypusine signaling is a critical regulator of VSMC proliferation for neointimal hyperplasia. Inhibiting DHPS reduces vascular remodeling, making it a promising target for preventing restenosis after coronary interventions. Clinical PerspectiveO_ST_ABSWhat Is New?C_ST_ABSO_LIHypusine signaling is markedly upregulated in coronary artery smooth muscle cells (CoASMCs) from patients with coronary artery disease (CAD) and in multiple preclinical models of restenosis. C_LIO_LIProteomic profiling identifies DHPS, the rate-limiting enzyme for eIF5A hypusination, as a key driver of vascular smooth muscle cell (VSMC) pro-proliferative phenotype and extracellular matrix production. C_LIO_LIPharmacological (GC7) and genetic inhibition of DHPS effectively suppress eIF5A hypusination, attenuate the synthetic and proliferative CAD-CoASMCs phenotype, and significantly reduce neointimal hyperplasia in rodent models of vascular injury. C_LIO_LIEx vivo human tissue demonstrates that DHPS inhibition prevents neointimal hyperplasia, providing strong translational evidence. C_LI What Are the Clinical Implications?O_LIThese findings establish hypusine signaling as a previously unrecognized regulator of pathological VSMC activation in CAD and restenosis. C_LIO_LIDHPS inhibition emerges as a promising therapeutic strategy to prevent neointimal hyperplasia following coronary interventions such as angioplasty, stenting, or bypass grafting. C_LIO_LICollectively, our data support the clinical development of selective DHPS inhibitors as a novel class of therapeutics to improve long-term outcomes after coronary revascularization and potentially other occlusive vascular diseases. C_LI