Antagonism of the Prokineticin System Prevents and Reverses Allodynia and Inflammation in a Mouse Model of Diabetes

Abstract

Neuropathic pain is a severe diabetes complication and its treatment is not satisfactory. It is associated with neuroinflammation-related events that participate in pain generation and chronicization. Prokineticins are a new family of chemokines that has emerged as critical players in immune system, inflammation and pain. We investigated the role of prokineticins and their receptors as modulators of neuropathic pain and inflammatory responses in experimental diabetes. In streptozotocin-induced-diabetes in mice, the time course expression of prokineticin and its receptors was evaluated in spinal cord and sciatic nerves, and correlated with mechanical allodynia. Spinal cord and sciatic nerve pro- and anti-inflammatory cytokines were measured as protein and mRNA, and spinal cord GluR subunits expression studied. The effect of preventive and therapeutic treatment with the prokineticin receptor antagonist PC1 on behavioural and biochemical parameters was evaluated. Peripheral immune activation was assessed measuring macrophage and T-helper cytokine production. An up-regulation of the Prokineticin system was present in spinal cord and nerves of diabetic mice, and correlated with allodynia. Therapeutic PC1 reversed allodynia while preventive treatment blocked its development. PC1 normalized prokineticin levels and prevented the up-regulation of GluN2B subunits in the spinal cord. The antagonist restored the pro-/anti-inflammatory cytokine balance altered in spinal cord and nerves and also reduced peripheral immune system activation in diabetic mice, decreasing macrophage proinflammatory cytokines and the T-helper 1 phenotype. The prokineticin system contributes to altered sensitivity in diabetic neuropathy and its inhibition blocked both allodynia and inflammatory events underlying disease.

Therapeutic effect of human adipose-derived stem cells and their secretome in experimental diabetic pain

“…Diabetes was induced by intraperitoneal (i.p.) administration of Moderate Low Doses of streptozotocin (STZ) (80 mg/kg daily for three consecutive days) 8 , (Sigma Aldrich, Italy), in citrate buffer 0.1 M, pH 4.55. Control mice were injected with citrate buffer.…”

“…Splenocytes were adjusted in 24-well plates at the final concentration of 4 × 10 6 cells/ml of culture medium (RPMI 1640 with 10% FCS, 1% glutamine, 2% antibiotics and 0.1% 2-mercaptoethanol) and incubated at 37 °C in 5% CO 2 and 95% air with 10 μg/ml Concanavalin A (ConA) for T helper (Th)1 and Th2 cytokine stimulation. After 24 (for IFN-γ and IL-2) or 48 hours (for IL-4 and IL-10) of culture, times of maximum release 8 , 65 , supernatants were stored at −80 °C.…”

“…They start a cascade of neuroinflammation-related events that may maintain and worsen the original injury, participating in pain generation and chronicization 4 – 7 . A large activation of inflammatory cascade, proinflammatory cytokine upregulation, and neuroimmune communication pathways plays a vital role in structural and functional damage of peripheral nerves, leading to the diabetic peripheral neuropathy 8 , 9 .…”

Prokineticin Receptor Inhibition With PC1 Protects Mouse Primary Sensory Neurons From Neurotoxic Effects of Chemotherapeutic Drugs in vitro

“…We are aware that a limitation of this study could be that the PK system, markers, and cytokines are evaluated only as mRNA levels. However, in our previous works that evaluated PK system and pro-inflammatory mediators in DRG in ex vivo experiments, mRNA and protein were similarly modulated (18,21,30). Moreover, other authors, using primary cortical neurons, demonstrated a parallel modulation of the PK system as mRNA and protein (34,47).…”

“…The specificity of the antagonist and the lack of off-target effects are supported by several published evidences. In vivo, when administered alone in normal mice, PC1 did not induce behavioral/biochemical alterations (18,22). The antagonist did not counteract hypersensitivity induced by PGE2, ATP, or bradykinin.…”