Increased chemokine signaling in a model of HIV1-associated peripheral neuropathyReport as inadecuate

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Molecular Pain

, 5:48

First Online: 12 August 2009Received: 03 March 2009Accepted: 12 August 2009


Painful distal sensory polyneuropathy DSP is the most common neurological complication of HIV1 infection. Although infection with the virus itself is associated with an incidence of DSP, patients are more likely to become symptomatic following initiation of nucleoside reverse transcriptase inhibitor NRTI treatment. The chemokines monocyte chemoattractant protein-1 MCP1-CCL2 and stromal derived factor-1 SDF1-CXCL12 and their respective receptors, CCR2 and CXCR4, have been implicated in HIV1 related neuropathic pain mechanisms including NRTI treatment in rodents. Utilizing a rodent model that incorporates the viral coat protein, gp120, and the NRTI, 2-3-dideoxycytidine ddC, we examined the degree to which chemokine receptor signaling via CCR2 and CXCR4 potentially influences the resultant chronic hypernociceptive behavior. We observed that following unilateral gp120 sciatic nerve administration, rats developed profound tactile hypernociception in the hindpaw ipsilateral to gp120 treatment. Behavioral changes were also present in the hindpaw contralateral to the injury, albeit delayed and less robust. Using immunohistochemical studies, we demonstrated that MCP1 and CCR2 were upregulated by primary sensory neurons in lumbar ganglia by post-operative day POD 14. The functional nature of these observations was confirmed using calcium imaging in acutely dissociated lumbar dorsal root ganglion DRG derived from gp120 injured rats at POD 14. Tactile hypernociception in gp120 treated animals was reversed following treatment with a CCR2 receptor antagonist at POD 14. Some groups of animals were subjected to gp120 sciatic nerve injury in combination with an injection of ddC at POD 14. This injury paradigm produced pronounced bilateral tactile hypernociception from POD 14–48. More importantly, functional MCP1-CCR2 and SDF1-CXCR4 signaling was present in sensory neurons. In contrast to gp120 treatment alone, the hypernociceptive behavior associated with the injury plus drug combination was only effectively reversed using the CXCR4 antagonist AMD3100. These studies indicate that the functional upregulation of CCR2 and CXCR4 signaling systems following a combination of gp120 and an NRTI are likely to be of central importance to associated DSP and may serve as potential therapeutic targets for treatment of this syndrome.

Electronic supplementary materialThe online version of this article doi:10.1186-1744-8069-5-48 contains supplementary material, which is available to authorized users.

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Author: Sonia K Bhangoo - Matthew S Ripsch - David J Buchanan - Richard J Miller - Fletcher A White


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