CD40 Is Essential in the Upregulation of TRAF Proteins and NF-KappaB-Dependent Proinflammatory Gene Expression after Arterial Injury

Abstract

Despite extensive investigations, restenosis, which is characterized primarily by neointima formation, remains an unsolved clinical problem after vascular interventions. A recent study has shown that CD40 signaling through TNF receptor associated factor 6 (TRAF6) plays a key role in neointima formation after carotid artery injury; however, underlying mechanisms are not clearly elucidated. Because neointima formation may vary significantly depending on the type of injury, we first assessed the effect of CD40 deficiency on neointima formation in 2 injury models, carotid artery ligation and femoral artery denudation injury. Compared with wild-type mice, CD40 deficiency significantly reduced neointima formation and lumen stenosis in two different models. Further, we investigated the mechanism by which CD40 signaling affects neointima formation after arterial injury. In wild-type mice, the expression levels of CD40, several TRAF proteins, including TRAF1, TRAF2, TRAF3, TRAF5, and TRAF6, as well as total NF-kB p65 and phospho-NF-kB p65, in the carotid artery were markedly upregulated within 3–7 days after carotid ligation. Deficiency of CD40 abolished the injury-induced upregulation of TRAFs including TRAF6 and NF-kB-p65 in the injured vessel wall. Further, CD40−/− mice showed a significant decrease in the recruitment of neutrophils (at 3, 7d) and macrophages (at 7, 21d) into injured artery; this effect was most likely attributed to inhibition of NF-kB activation and marked downregulation of NF-kB-related gene expression, including cytokines (TNFα, IL-1β, IL-6), chemokines (MCP-1), and adhesion molecules (ICAM-1, VCAM-1). Moreover, neutrophil recruitment in a model of thioglycollate-induced peritonitis is impaired in CD40-deficient mice. In vitro data revealed that CD40 deficiency blocked CD40L-induced NF-kB p65 nuclear translocation in leukocytes. Altogether, our data identified for the first time that CD40 is essential in the upregulation of TRAF6, NF-kB activation, and NF-kB-dependent proinflammatory genes in vivo. Our findings firmly established the role for CD40 in neointima formation in 2 distinct injury models.

Prostaglandin E2-EP4 signaling persistently amplifies CD40-mediated induction of IL-23 p19 expression through canonical and non-canonical NF-κB pathways

“…Involvement of NF-kB in the induction of Il23a mRNA expression under the CD40 signaling in BMDCs Because the transcription factor NF-kB is activated downstream of CD40 signaling, 21 we examined whether NF-kB was essential for the induction of Il23a mRNA expression in CD40-stimulated BMDCs and the synergistic action of EP4 signaling. Consistent with the previous report, the treatment with an anti-CD40 antibody augmented nuclear translocation of the NF-kB p65 subunit (Figure 2a), and increased phosphorylation of the NF-kB p65 subunit at serine 536 residue ( Figure 2b).…”

“…(f) Effect of NF-kB p100 depletion on Il23a mRNA expression in BMDCs stimulated with an anti-CD40 antibody with or without the EP4 agonist. BMDCs were treated with siRNA for p100 or scrambled siRNA for 48 h, and then stimulated with an anti-CD40 antibody (10 mg mL 21 ) and/or the EP4 agonist (ONO-AE1-329, 100 nM) for an additional 12 h. Total RNA from stimulated cells was prepared for quantitative RT-PCR analysis. n 5 3 in each group.…”

Role of TRAF3 in neurological and cardiovascular diseases: an overview of recent studies

“…In stroke, TRAF3 is associated with neuronal death (11,13), although other associations with other neurological conditions such as spinal cord injury (SCI) (15) and multiple sclerosis (17) have also been observed. In cardiovascular disease, an altered expression of TRAF3 is related with cardiac hypertrophy (10), atherosclerosis (18,19) and arterial injury (20).…”

“…Another study evaluated the role of CD40 and TRAF proteins in the underlying mechanism of restenosis (neointima formation) after artery injury in mice (20). The authors observed upregulation of CD40, TRAF proteins, including TRAF3, NF-κβ p65 and phospho-NF-κβ p65 in the injured carotid artery (20).…”

Expression and Role of ICAM-1 in the Occurrence and Development of Hepatocellular Carcinoma

“…The current study shows that, NF-kB is strongly activated in the early stage of artery damage, and together with increasing expression of ICAM-1, MCP-1, TNF-a, IL-1b, IL-6 and so on. ICAM-1 and VCAM -1 strongly raise various inflammatory cytokines into the area, promoting the formation of vascular intima (Song et al, 2011). Studies on isolated endothelial cells show that ,isolated tumor endothelial cells (TEC) and normal endothelial cells (NEC), together, expressed CD31, CD105, VE-cadherin, vascular cellular adhesion molecule-1 (VCAM-1), ICAM-1, and E-selectin, and formed capillaries in basal membrane (Naschberger et al, 2011).…”