Effect of a Broad-Specificity Chemokine-Binding Protein on Brain Leukocyte Infiltration and Infarct Development

Abstract

Background and Purpose-Expression of numerous chemokine-related genes is increased in the brain after ischemicstroke. Here, we tested whether post-stroke administration of a chemokine-binding protein (CBP), derived from the parapoxvirus bovine papular stomatitis virus, might reduce infiltration of leukocytes into the brain and consequently limit infarct development. Methods-The binding spectrum of the CBP was evaluated in chemokine ELISAs, and binding affinity was determined using surface plasmon resonance. Focal stroke was induced in C57Bl/6 mice by middle cerebral artery occlusion for 1 hour followed by reperfusion for 23 or 47 hours. Mice were treated intravenously with either bovine serum albumin (10 μg) or CBP (10 μg) at the commencement of reperfusion. At 24 or 48 hours, we assessed plasma levels of the chemokines CCL2/MCP-1 and CXCL2/MIP-2, as well as neurological deficit, brain leukocyte infiltration, and infarct volume. Results-The CBP interacted with a broad spectrum of CC, CXC, and XC chemokines and bound CCL2/MCP-1 and CXCL2/MIP-2 with high affinity (pM range). Stroke markedly increased plasma levels of CCL2/MCP-1 and CXCL2/ MIP-2, as well as numbers of microglia and infiltrating leukocytes in the brain. Increases in plasma chemokines were blocked in mice treated with CBP, in which there was reduced neurological deficit, fewer brain-infiltrating leukocytes, and ≈50% smaller infarcts at 24 hours compared with bovine serum albumin-treated mice. However, CBP treatment was no longer protective at 48 hours. Conclusions-Post-stroke administration of CBP can reduce plasma chemokine levels in association with temporary attenuation of brain inflammation and infarct volume development.

A Broad-Spectrum Chemokine-Binding Protein of Bovine Papular Stomatitis Virus Inhibits Neutrophil and Monocyte Infiltration in Inflammatory and Wound Models of Mouse Skin

“…The BPSV-CBP was expressed in 293-EBNA cells as a FLAG-fusion protein and purified by affinity chromatography as described previously [21]. The purified CBP was analysed by multi-angle laser-light scattering (MALLS) (Wyatt Technology) coupled with size-exclusion chromatography (SEC) [20].…”

“…Previous studies of PPVs, in particular the type species orf virus (ORFV), revealed they have evolved a range of mechanisms that temporarily suppress inflammation within the infected site and delay the host’s immune response. These anti-inflammatory mechanisms include the secretion of a viral homolog of interleukin-10 that reduces the production of pro-inflammatory cytokines [9–16], and also secretion of a chemokine-binding protein (CBP) that impairs the chemokine network [14,17–21]. In the case of BPSV, this combination of secreted viral immunomodulators in conjunction with other virulence factors may be associated with frequent subclinical infections, reinfections, and virus persistence in its natural host [6,7,22,23].…”

“…Recently we reported that the BPSV-CBP can target specific inflammatory chemokines and consequently suppress inflammation in a post-stroke treatment of the mouse brain [21]. Increases in plasma chemokines associated with stroke, in particular CCL2 and CXCL2 were blocked in mice treated with CBP and this was associated with reduced neurological deficit, fewer brain infiltrating leukocytes, and a smaller infarct compared with the control.…”

Evidence That Ly6C hi Monocytes Are Protective in Acute Ischemic Stroke by Promoting M2 Macrophage Polarization

“…3 As leukocyte activation in association with postischemic inflammation contributes to secondary brain injury, 4,5 pharmacological targeting of chemokine receptors may be an attractive means to selectively exclude immune cells that might worsen acute damage in the initial period after a stroke. 6,7 The influence of monocytes/macrophages on brain infarct development and stroke outcome is not well defined. The 2 common types of murine monocytes are classified by their level of Ly6C expression: Ly6C hi and Ly6C lo .…”

Protein microarray analysis identifies key cytokines associated with malignant middle cerebral artery infarction

“…The red nodes are the screened differentially expressed cytokines in our study be responsible for the migration of peripheral immune cell into the brain in neuroinflammatory conditions (Cazareth, Guyon, Heurteaux, Chabry, & Petit-Paitel, 2014). CCL2 expression is also associated with the infarct volume which plays a pivotal role in brain inflammation and infarct volume development after ischemic stroke (Lee et al, 2015). Although cytokine-cytokine receptor interaction pathway has not been fully discussed in this study, considering the important roles of these cytokines, our results imply that the above down-regulated cytokines may participate in the progression of MMI via involving in cytokine-cytokine receptor interaction pathway.…”