The chemokine Bv8/prokineticin 2 is up-regulated in inflammatory granulocytes and modulates inflammatory pain

Abstract

Neutrophil migration into injured tissues is invariably accompanied by pain. Bv8/prokineticin 2 (PK2), a chemokine characterized by a unique structural motif comprising five disulfide bonds, is highly expressed in inflamed tissues associated to infiltrating cells. Here, we demonstrate the fundamental role of granulocyte-derived PK2 (GrPK2) in initiating inflammatory pain and driving peripheral sensitization. In animal models of complete Freund's adjuvantinduced paw inflammation the development and duration of pain temporally correlated with the expression levels of PK2 in the inflamed sites. Such an increase in PK2 mRNA depends mainly on a marked up-regulation of PK2 gene transcription in granulocytes. A substantially lower up-regulation was also detected in macrophages. From a pool of peritoneal granulocytes, elicited in rats by oyster glycogen, we purified the GrPK2 protein, which displayed high affinity for the prokineticin receptors (PKRs) and, when injected into the rat paw, induced hypersensitivity to noxious stimuli as the amphibian prokineticin Bv8 did. Mice lacking PKR1 or PKR2 developed significantly less inflammation-induced hyperalgesia in comparison with WT mice, confirming the involvement of both PKRs in inflammatory pain. The inflammation-induced upregulation of PK2 was significantly less in pkr1 null mice than in WT and pkr2 null mice, demonstrating a role of PKR1 in setting PK2 levels during inflammation. Pretreatment with a nonpeptide PKR antagonist, which preferentially binds PKR1, dose-dependently reduced and eventually abolished both prokineticin-induced hypernociception and inflammatory hyperalgesia. Inhibiting PK2 formation or antagonizing PKRs may represent another therapeutic approach for controlling inflammatory pain.hypernociception ͉ inflammation ͉ prokineticin receptors

Granulocyte-colony stimulating factor promotes lung metastasis through mobilization of Ly6G+Ly6C+ granulocytes

“…S1D). Bv8 is a secreted protein that has been previously characterized as a proangiogenic factor (12), an inducer of growth and mobilization of hematopoietic cells (13), and a neuromodulator (14,15). Quantitative (q)RT-PCR analysis of Bv8 expression in lung tissues confirmed the microarray results (Fig.…”

Prokineticins are neuroprotective in models of cerebral ischemia and ischemic tolerance in vitro

“…Neuroprotective effects of Bv8 (PK2) in mixed murine cortical cultures and rat organotypic hippocampal slices exposed to oxygen and glucose deprivation (OGD) Bv8 can be used as a suitable pharmacological tool to investigate the effects of PK2 in vitro and in vivo (Giannini et al, 2009;Severini et al, 2015). To investigate the possible neuroprotective effects of Bv8 we carried out experiments in cultured murine cortical cells exposed to OGD, an in vitro model of focal cerebral ischemia routinely used in our lab (Pellegrini-Giampietro et al, 1999a).…”

“…Bv8 was isolated from skin secretions of the frog Bombina variegata as previously described (Giannini et al, 2009) and purified to 98% as assessed by highperformance liquid chromatography. PC7 (2-(5-(4-fluorobenzyl)-1-(4-methoxybenzyl)-1,4,5,6-tetrahydro-4,6-dioxo-1,3,5-triazin-2-ylamino)-ethyl)-guanidine), a triazinic compound which displays approximately 75-fold higher affinity for PKR1 than for PKR2, was synthesized as previously described (Congiu et al, 2014).…”

“…cDNAs were amplified by real-time PCR (iCycler; Bio-Rad) using iQ SYBER Green Supermix (Bio-Rad). Specific sense and antisense primers were synthesized (Biogen, Rome, Italy) to PCR amplify the rat PK2, PKR1 and PKR2 cDNA, according to the following sequences previously described (Giannini et al, 2009): PK2, 5 0 -CAAGGACTCTCAGTGTGGA-3 0 and 5 0 -AAAATG-GAACTTTCCGAGTC-3 0 ; PKR1, 5 0 -CGCACCGTCTCCCTCTAC-3 and 5 0 -GTTTGACACTTCATCCGCG-3 0 ; PKR2, 5 0 CTCCGTCAACTACCTTCGTA-3 0 and 5 0 -GAGGCGGTCTGGTAATTCA-3 0 .…”

“…The mammalian prokineticin family includes two small bioactive peptides (8e12 kDa) that stimulate guinea-pig ileum contraction termed prokineticin 1 (PK1) (also known as endocrine gland-vascular endothelial growth factor, EG-VEGF) and PK2 (the mammalian analog of Bv8). These two peptides are highly conserved across species (LeCouter et al, 2004;Giannini et al, 2009) and activate two highly homologous receptors, prokineticin receptor 1 (PKR1) and PKR2 (Negri and Lattanzi, 2011), which are coupled to a variety of G proteins and hence to intracellular Ca 2þ mobilization and activation of the ERK1/2 and Akt pathways (Lin et al, 2002;Masuda et al, 2002;Soga et al, 2002). Prokineticins (especially PK2) and their receptors are largely expressed in CNS (Cheng et al, 2006) and regulate multiple biological functions in the CNS including hyperalgesia (Mollay et al, 1999), neurogenesis in the olfactory bulb (Ng et al, 2005), neuronal survival (Melchiorri et al, 2001) and inflammation (Martucci et al, 2006).…”