NF-κB inhibitor targeted to activated endothelium demonstrates a critical role of endothelial NF-κB in immune-mediated diseases

Abstract

Activation of the nuclear transcription factor κB (NF-κB) regulates the expression of inflammatory genes crucially involved in the pathogenesis of inflammatory diseases. NF-κB governs the expression of adhesion molecules that play a pivotal role in leukocyteendothelium interactions. We uncovered the crucial role of NF-κB activation within endothelial cells in models of immune-mediated diseases using a "sneaking ligand construct" (SLC) selectively inhibiting NF-κB in the activated endothelium. The recombinant SLC1 consists of three modules: (i) an E-selectin targeting domain, (ii ) a Pseudomonas exotoxin A translocation domain, and (iii) a NF-κB Essential Modifier-binding effector domain interfering with NF-κB activation. The E-selectin-specific SLC1 inhibited NF-κB by interfering with endothelial IκB kinase 2 activity in vitro and in vivo. In murine experimental peritonitis, the application of SLC1 drastically reduced the extravasation of inflammatory cells. Furthermore, SLC1 treatment significantly ameliorated the disease course in murine models of rheumatoid arthritis. Our data establish that endothelial NF-κB activation is critically involved in the pathogenesis of arthritis and can be selectively inhibited in a cell type-and activation stage-dependent manner by the SLC approach. Moreover, our strategy is applicable to delineating other pathogenic signaling pathways in a cell type-specific manner and enables selective targeting of distinct cell populations to improve effectiveness and riskbenefit ratios of therapeutic interventions.cell targeting | intracellular signaling | autoimmune disorders | mouse models | inhibit inflammation A critical step in the effector phase of pathogenic immune responses is the extravasation of circulating leukocytes from the vasculature and their migration along gradients of chemoattractants into the target tissues (1). In inflammation, endothelial activation represents a multistep cascade of events leading to increased vascular permeability for plasma proteins; the expression of proinflammatory cytokines, chemokines, and enzymes; and an up-regulation of adhesion molecules that are regulated by the nuclear transcription factor κB (NF-κB) (2-4).Activation of NF-κB via the IκB kinase (IKK) complex is regarded as the classical NF-κB pathway. The IKK complex contains the kinases IKK1 and IKK2 and the regulatory subunit NF-κB Essential Modifier (NEMO) (5). Activation of the classical NF-κB pathway requires association of NEMO with IKK2 (5). The expression of multiple proinflammatory genes including the adhesion molecules ICAM-1, VCAM-1, E-selectin, and chemokines, like MCP-1 and IL-8, contributes to the inflammatory endothelial cell response and is initiated through activation of the classical NF-κB pathway (6).

CARMA3 Is Critical for the Initiation of Allergic Airway Inflammation

“…However, these studies suggest that targeting the NF-κB in a cell- and pathway-specific manner could be beneficial in treating asthma. Consistent with this, selectively inhibiting NF-κB in endothelial cells in a murine models of peritonitis and rheumatoid arthritis has been shown to ameliorate both disease courses (113). These data together with the data in this manuscript, suggest that the NF-κB pathway can be selectively inhibited in a cell type- and activation stage-dependent manner (113).…”

Etanercept administration prevents the inflammatory response induced by carrageenan in the murine air pouch model

“…In fact, most of the pro-inflammatory cytokines are associated with RA and are regulated by NF-κB (Tanaka et al 2014). The activation of this nuclear transcription factor pathway promotes an enhancement in the expression of adhesion molecules such as intracellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), E-selectin, and the increased release of chemokines and cytokines such as IL-1 and IL-8 (Sehnert et al 2013) Additionally, NF-κB is essential for the development and maturation of all hematopoietic cells including macrophage and neutrophils (Denk et al 2000). It is important to note that neutrophils are present in RA synovial fluid in the early disease stages, where they initiate and maintain joint inflammation, also, through NETosis, may release citrullinated autoantigens that are implicated in RA pathogenesis (Kaplan 2013).…”

Cooperative Signaling via Transcription Factors NF-κB and AP1/c-Fos Mediates Endothelial Cell STIM1 Expression and Hyperpermeability in Response to Endotoxin

“…Experimental animal model studies have demonstrated that inhibition of NF-B activation suppresses inflammatory responses (16,17). This transcription factor may also be involved in signaling increased Ca 2ϩ entry in ECs (9,18).…”