Study Of Wnt5a Signaling Regulation In Neuroinflammation Induced By NRTI

The highly active anti-retroviral therapy(HAART)is very successful in suppressing the replication of HIV-1 virus in patients.However,the HIV-1 patients who are receiving long-term treatment of HAART,are found to easily develop into neurological disorders despite decreased HIV loads.Neuroinflammation,a characteristic hallmark of neurological disorder,is closely associated with a variety of neurocognitive disorders such as dementia,Alzheimer’s disease,Parkinson’s disease and chronic pain.Wnt5 a,a prototypic ligand for the non-canonical Wnt signaling pathway,plays essential roles in development and signal transduction.Recently,Wnt5 a is also revealed to regulate inflammation.We then hypothesize that NRTI treatment might cause persistent neuroinflammation regulated by Wnt5 a.This study will not only reveal novel mechanisms of NRTI-induced neuroinflammation but also identify pharmaceutical targets for the future therapy.In this study,mice(C57Bl/6)were administered with AZT(100 mg/kg,sc./days),3TC(50 mg/kg;sc./days)or D4T(10 mg/kg;sc./ days)for 2,5,10,or 14 days and CNS tissues were collected at the end of NRTI treatment.Western blotting analysis is performed to determine the expression levels of IL-1β,TNF-α and IL-6 in the different CNS tissues,including cortex,hippocampus and spinal cord.Western blotting analysis showed that IL-1β,TNF-α and IL-6 significantly increased in the CNS tissues of NRTI treated mice,suggesting that NRTI evokes neuroinflammation through high level releasing of cytokines.We sought to identify the cell type of CNS immune-responsive cells that contributes to the NRTI induced cytokine expression.Using GFAP and CD11 b as a molecular marker of activated astrocytes and microglias respectively,we observed that NRTI causes a dramatic activation of astrocytes in CNS as revealed by immunocytochemistry staining.In contrast,microglias were not markedly activated under these conditions.In order to investigate whether NRTI cause neuropathic changes in the CNS,we performed HE staining and found that Short-term Exposure to NRTI did not induce neuropathy in cortex,hippocampus or spinal cord.Recently,Wnt5 a is reported as an important regulator of TNF-α and IL-1β expression in primary cortical cultures.We thus examined if Wnt5 a is involved in NRTI induced neuroinflammation.Indeed,as shown by Western blotting,Wnt5 a was increased in the CNS of NRTI treated mice.To elucidate the critical role of Wnt5 a in NRTI-induced neuroinflammation,BOX5,a specific Wnt5 a antagonist,was applied to the study.Importantly,we observed that BOX5 attenuates NRTI-induced cytokine up-regulation.Similar effects of BOX5 on inhibition of NRTI-induced cytokines were also found by immunocytochemistry staining.In summary,Wnt5 a signal cascades play a crucial role in the regulation of NRTI-induced neuroinflammation.