High Mobility Group Box 1 Mediates Interferon-γ-Induced Phenotypic Modulation of Vascular Smooth Muscle Cells

Abstract

The phenotypic modulation of VSMCs is a key cellular event driving neointimal formation and vascular remodeling. As a multifaceted cytokine of cell-mediated immunity, IFN-γ has been shown to play a critical role in the pathogenesis of vascular proliferative diseases. Although the important function of IFN-γ on regulating VSMC activation is well established, the molecular mechanisms by which elicits VSMC responses are poorly defined. Recent studies have identified HMGB1 as a principal effector to mediate IFN-γ-dependent biological functions in multiple cell types. Moreover, SIRT1 has emerged as a critical regulator of cellular processes through deacetylating multiple substrates, including HMGB1. Thus, we examined the role of IFN-γ on HMGB1 release, SIRT1 expression, and VSMC phenotypic modulation as well as the underlying molecular mechanisms. We show that IFN-γ dose-dependently induces HMGB1 cytoplasmic accumulation and its active release from VSMCs, resulting in enhanced HMGB1 in the medium. Conversely, IFN-γ treatment led to a dramatic decrease in SIRT1 expression. Additionally, pretreatment with resveratrol, a selective SIRT1 activator, abrogated IFN-γ-induced HMGB1 translocation and its release. Moreover, IFN-γ stimulates VSMC phenotypic modulation to an activated synthetic state characterized by the repression of SMC differentiation markers such as SM22α and calponin and the increase in cell motility. In contrast, blocking HMGB1 release or activity by resveratrol and HMGB1-neutralizing antibody prevents IFN-γ-induced phenotypic modulation of VSMCs. Overall, this study provides the first evidence showing that HMGB1 plays a critical role in regulating VSMC phenotypic modulation, suggesting that HMGB1 may be a potential therapeutic target to prevent vascular occlusive diseases. J. Cell. Biochem. 118: 518-529, 2017. © 2016 Wiley Periodicals, Inc.

PI3Kγ promotes vascular smooth muscle cell phenotypic modulation and transplant arteriosclerosis via a SOX9-dependent mechanism

“…BrdU incorporation assay was performed to assess cell proliferation as previously described [ 28 ]. Suspended cells were seeded into 96-well plates at a density of 5 × 10 3 cells per well, allowed to attach and grow overnight.…”

“…VSMC migration was evaluated by wound-healing and Transwell migration assays as previously desired [ 28 ]. About ~90% confluence, cells were starved for 48 h prior to scratch wounding.…”

HMGB1 Increases IL-1β Production in Vascular Smooth Muscle Cells via NLRP3 Inflammasome

“…The phenotypic modulation of VSMCs is a key cellular event that drives neointima formation and vascular remodeling. Reportedly, the phenotypic modulation of VSMCs induced by interferon-γ is mediated by high mobility group box-1 (HMGB1), a non-histone chromosomal protein (Wang et al, 2017 ). HMGB1 is released by monocytes/macrophages in response to inflammatory stimuli and then binds to DNA in a sequence-independent manner and modifies DNA structure, and thereby facilitates gene transcription (Kalinina et al, 2004 ; Stott et al, 2006 ; Yang et al, 2015 ).…”

“…In blood vessels, high levels of extracellular HMGB1 have been detected in human atherosclerotic plaque, and reportedly are implicated in vascular inflammation by potentiating inflammatory responses (Kalinina et al, 2004 ; Cai et al, 2015 ). It has also been shown that HMGB1 modulates the phenotype of VSMCs toward the activated synthetic phenotype and stimulates MCP-1/CCL2 gene expression through toll-like receptor 4 (TLR4) (Cai et al, 2015 ; Wang et al, 2017 ). However, the nature of the links between VSMCs, HMGB1, and vascular inflammation have not been clarified.…”

Downregulation of Lysosomal Acid Ceramidase Mediates HMGB1-Induced Migration and Proliferation of Mouse Coronary Arterial Myocytes

“…Coronary arterial myocytes are the primary cell type in blood vessel walls and play essential roles in pathogenesis of vascular diseases. By transforming from the contractile to the synthetic phenotype, the CAMs exhibit distinct proliferative and migratory abilities and produce pro-inflammatory cytokines (Wang K. et al, 2017;Zhang et al, 2018). HMGB1 was demonstrated to stimulate cell proliferation and migration in a variety of mammalian cells including fibroblasts (Chitanuwat et al, 2013), airway SMCs (Hou et al, 2019), osteosarcoma cells (Guo et al, 2014), and cancer cells (He et al, 2018).…”