Wnt5A/CaMKII Signaling Contributes to the Inflammatory Response of Macrophages and Is a Target for the Antiinflammatory Action of Activated Protein C and Interleukin-10

Abstract

Objective-Sepsis is a major cause of death for intensive care patients. High concentrations of inflammatory cytokines are characteristic of severe systemic inflammation and activated monocytes are their predominant cellular source. To identify targets for antiinflammatory intervention, we investigated the response of human macrophages to inflammatory and antiinflammatory mediators. Methods and Results-We profiled gene expression in human macrophages exposed to lipopolysaccharide (LPS) and interferon (IFN)-␥ in the presence or absence of recombinant activated protein C (APC) or IL-10 and identified Wnt5A as one of the transcripts most highly induced by LPS/IFN-␥ and suppressed by APC and IL-10. We confirmed regulation of Wnt5A protein in macrophages and detected it in sera and bone marrow macrophages of patients with severe sepsis. We established that a functional Wnt5A/frizzled-5/CaMKII signaling pathway was essential for macrophage inflammatory activation. To prove the essential contribution of Wnt5A we measured inflammatory cytokines after stimulation with Wnt5A, silenced Wnt5A by siRNA, and blocked receptor binding with soluble Frizzled-related peptide-1 (sFRP1). Key Words: geneexpression Ⅲ macrophages Ⅲ activated protein C S epsis is a suspected or proven infection with a systemic inflammatory response. In severe sepsis, organ dysfunction also occurs and it is associated with a high mortality and morbidity. Severe sepsis still causes about 9.3% of all deaths in the USA. 1,2 Conclusion-Wnt5A is critically involved in inflammatory macrophage See accompanying article on page 400During sepsis, the extent of plasma protein C depletion correlates with the severity of the outcome. 3 In animal studies 4 and clinical trials APC prevented death from severe sepsis or septic shock. 5 Although this beneficial effect of APC is mostly ascribed to its anticoagulant properties, antiinflammatory effects of APC have also been proposed. 6 The direct modulation of inflammation by APC has recently been described in gene expression profiling studies with human endothelial cells. 7,8 Recently, recombinant human APC has been introduced as a therapeutic agent for treatment of patients with severe sepsis because of its unique anticoagulant and antiinflammatory properties; however, the exact mechanism of antiinflammatory action is still unknown. 9 Macrophages play a central role in inflammation by responding to and releasing of numerous inflammatory cytokines and chemokines, leading to severe systemic inflammation and septic shock. However, the knowledge of antiinflammatory interactions on the level of monocytes/macrophages is scant. Therefore, we decided to expand our investigations on antiinflammatory effects of APC on this cellular system. In the present study, we were using a whole genome expression analysis approach, to define novel targets of APC in an in vitro model of inflammatory macrophage activation. Using probes obtained from human macrophages stimulated by INF-␥ (IFN-␥) and endotoxin (LPS), we consistently found Wnt5A to ...

Autocrine stimulation of osteoblast activity by Wnt5a in response to TNF-α in human mesenchymal stem cells

“…In addition to preventing excessive bone formation, inhibition of Wnt5a may also reduce the neighboring bone resorption that characterize patients with AS, since osteoblast-derived Wnt5a stimulates osteoclastogenesis [42]. Finally, Wnt5a blockade may also impact the secretion of inflammatory mediators such as IL-6, IL-1b and IL-8 [38]. In our hands, Wnt5a stimulated the expression of COX-2, an important enzyme in inflammation and bone repair.…”

“…Interestingly, Wnt5a is expressed in response to a panel of inflammatory stimuli and exerts inflammatory functions [38]. Wnt5a is for instance expressed in joints of patients with RA [39].…”

Recombinant Wnt3a and Wnt5a elicit macrophage cytokine production and tolerization to microbial stimulation via Toll‐like receptor 4

“…Clinical associations of elevated Wnt expression and pathway activity with infections [2,3,6] and chronic inflammatory diseases [8,9,11] have sparked significant interest in elucidating immune-related functions of Wnt signaling. There is strong experimental evidence for the contribution of endogenous Wnt proteins to inflammatory cytokine responses and host defense against pathogens in in vivo models [5,11,20] as well as in a variety of cell culture systems [2,6,13,14,36]. In a model of dietinduced metabolic dysfunction, sFRP5 exerted anti-inflammatory functions in vivo, possibly by interfering with Wnt5a-induced proinflammatory cytokine production [11].…”

“…The 19 mammalian homologues have distinct expression patterns in embryonic and adult tissues and their during infections with mycobacteria, Gram-negative and Grampositive bacteria [2][3][4][5][6], and chronic inflammation in rheumatoid arthritis, atherosclerosis, obesity, and psoriasis [7][8][9][10][11][12].…”

“…IL-12 and IL-6) and chemokines (e.g. CCL2 and CCL5) by macrophages and other cell types [2,6,11,13,14]. Wnt proteins, such as Wnt5a, which signal via β-Catenin-independent pathways, including Ca 2+ mobilization, NF-κB, and MAP kinase activation, have been proposed to amplify local inflammation [15,16].…”