ABSTRACT
Title
PC1, a prokineticin receptor antagonist, displays anti-inflammatory effects greater than that of indomethacin
Authors
L. A. Giancotti1, R. Lattanzi1, P. Spinsanti1, M. Canestrelli1, D. Maftei1, G. Balboni2, S. Salvadori3, L. Negri1
1Dept. of Physiology and Pharmacology “Vittorio Erspamer”, “Sapienza” University of Rome, Italy; 2Dept. of Toxicology, University of Cagliari, Cagliari, Italy; 3Dept. of Pharmaceutical Sciences, University of Ferrara, Ferrara, Italy.
1Dept. of Physiology and Pharmacology “Vittorio Erspamer”, “Sapienza” University of Rome, Italy; 2Dept. of Toxicology, University of Cagliari, Cagliari, Italy; 3Dept. of Pharmaceutical Sciences, University of Ferrara, Ferrara, Italy.
Abstract
Bv8, Prokineticin 1 (PK1) and Prokineticin 2 (PK2) are small proteins, identified in several species from reptiles to mammals. These chemokines, acting on two G-protein coupled receptors [prokineticin receptors 1 (PKR1) and prokineticin receptors 2 (PKR2)], on peripheral nociceptors and on circulating neutrophyls produce pro-inflammatory and pro-algesic effects. The endogenous mammalian homolog of Bv8, PK2, is up-regulated in an animal model of inflammation: complete freund's adjuvant (CFA) injected into the paw (Giannini et al., 2009). Because it was demonstrated that granulocyte-colony stimulating factor (G-CSF) is the main inducer of PK2 up-regulation in CD11b+Gr1+ bone marrow derived cells (Shojaei et al., 2007), we investigated the time-course of G-CSF serum levels (ELISA) in correlation with pain and with the PK2 expression levels into the CFA treated paw of mice. PC1 is a non-peptide PKR1-preferring antagonist endowed with a potent anti hyperalgesic effect; here we evaluated the effects of systemic administration of PC1 on thermal hyperalgesia, paw volume, G-CSF and PK2 levels in mice. Moreover, in rats bearing CFA inflamed paw, we compared the effects of PC1 with the effects of the potent anti-inflammatory agent indomethacin on mechanical hyperalgesia (Randall-Selitto test), paw edema (Plethismometer), PK2 expression and granulocyte recruitment.
In mice, PC1 (150 µg/kg, s.c.) administered immediately before, 5 and 10 hours after CFA-injection significantly decreased CFA-induced thermal hyperalgesia (Paw-immersion test) and the paw edema (Plethismometer) since 8 hours after CFA injection. PC1 treatment decreased the inflammation-induced PK2 up-regulation, but was ineffective on inflammation-induced G-CSF levels increase.
In rats, PC1 (500 µg/kg, s.c.) and indomethacin (5 mg/kg, s.c.) were administered 6 and 24 hours after CFA injection and their effects evaluated from 6 to 48 hours after CFA injection. 48 hours after CFA injection, rat’s paws were collected and PK2 paw expression levels (RT-PCR analysis), paw neutrophils content (Myeloperoxidase Assay, MPO) and fluid extra-vasation (Evans Blue) were assessed. Acute administration of PC1 completely reverted CFA-induced mechanical hypernociception for 2 hours, whereas acute administration of indomethacin only partially reduced the inflammation-induced mechanical hyperalgesia for 2 hours. PC1 treatment was significantly more efficacious than indomethacin treatment in reducing pain and paw volume after inflammation. PC1 and indomethacin treatment significantly reduced the CFA-induced paw granulocytes recruitment. PC1 treatment was more effective than indomethacin treatment in reducing the inflammtory induced PK2 up-regulation and fluid extra-vasation probably acting on prokineticin receptors that are present on endothelial cells.
Giannini et al., (2009). PNAS 106: 14646-14651.
Shojaei et al. (2007). Nature 450:825-831.
In mice, PC1 (150 µg/kg, s.c.) administered immediately before, 5 and 10 hours after CFA-injection significantly decreased CFA-induced thermal hyperalgesia (Paw-immersion test) and the paw edema (Plethismometer) since 8 hours after CFA injection. PC1 treatment decreased the inflammation-induced PK2 up-regulation, but was ineffective on inflammation-induced G-CSF levels increase.
In rats, PC1 (500 µg/kg, s.c.) and indomethacin (5 mg/kg, s.c.) were administered 6 and 24 hours after CFA injection and their effects evaluated from 6 to 48 hours after CFA injection. 48 hours after CFA injection, rat’s paws were collected and PK2 paw expression levels (RT-PCR analysis), paw neutrophils content (Myeloperoxidase Assay, MPO) and fluid extra-vasation (Evans Blue) were assessed. Acute administration of PC1 completely reverted CFA-induced mechanical hypernociception for 2 hours, whereas acute administration of indomethacin only partially reduced the inflammation-induced mechanical hyperalgesia for 2 hours. PC1 treatment was significantly more efficacious than indomethacin treatment in reducing pain and paw volume after inflammation. PC1 and indomethacin treatment significantly reduced the CFA-induced paw granulocytes recruitment. PC1 treatment was more effective than indomethacin treatment in reducing the inflammtory induced PK2 up-regulation and fluid extra-vasation probably acting on prokineticin receptors that are present on endothelial cells.
Giannini et al., (2009). PNAS 106: 14646-14651.
Shojaei et al. (2007). Nature 450:825-831.