The overarching goal of this investigation is to understand the mechanism(s) whereby the tachykinin neuropeptide, substance P (SP), and its preferred receptor, Neurokinin-lR (NK1R) modulate the immunopathogenesis of HIV as central mediators in the interaction between the immune and nervous systems. Our major hypothesis is that altered SP and NK1R, are mechanistically important in HIV pathogenesis and that this receptor and its ligand are altered in association with neurocognitive changes and life stress and depression in HIV-infected individuals. We showed that the non-peptide SP antagonist (CP-96,345) inhibits HIV replication in human mononuclear phagocytes through down-regulation of CCR5, the chemokine receptor, the principal co-receptor for HIV entry into macrophages and also by NK1R antagonist inhibition of endogenous SP production. The SP autocrine loop has an important role in regulating cytokine and inflammatory responses. HIV reciprocally enhances SP expression in human immune cells, eliciting a "feed-forward cycle". We discovered that cell differentiation in vitro from monocyte to macrophage phenotype (THP cells) results in the expression of both the NK1R-T (truncated) and NK1R-F (full-length), whereas the monocyte cell expresses only NK1R-T. The qualitative and quantitative expression of NK1R and its truncated (NK1R-T) and full length forms (NK1R-F) have functional consequences for calcium flux in macrophages. In the brain cingulate cortex, mRNA expression of both the NK1R-T and NK1R-F are reduced in HIV-infected subjects. We will use cells from both the immune and the CNS systems, including peripheral monocyte-macrophages and cells obtained from select human brain regions to examine these mechanisms. We will examine the cell biology of the interaction between NK1R (NK1R-F and NK1R-T) and HIV and chemokine receptors.
Our aims are: (1) To investigate expression of NK-1RF in monocyte-derived macrophages and their associations with CCR5, CD4, Fractalkine, and IL-8. (2) We will investigate the physical and functional interactions between NK1R-T, NK1R-F receptors and CCR5. (3) We will explore the role of cytosolic Ca2+ increase in the cross-talk between NK1R-F, NK1R-T, and CCR5. (4) We hypothesize that altered levels of either or both NK1R-T or NK1R-F mRNA and protein, or receptor function, are associated with alterations with cognitive function in HIV-1/AIDS infected individuals, and these effects alter CCR5-NK1R interaction. Relevance to Public Health: These studies will further lead to understanding the pathogenesis of neurocognitive changes in HIV disease and lead to unique and novel therapeutic intervention.
|Barrett, Jeffrey S; Spitsin, Sergei; Moorthy, Ganesh et al. (2016) Pharmacologic rationale for the NK1R antagonist, aprepitant as adjunctive therapy in HIV. J Transl Med 14:148|
|Douglas, Steven D (2016) Substance P and sickle cell disease-a marker for pain and novel therapeutic approaches. Br J Haematol 175:187-188|
|McGuire, Jennifer L; Gill, Alexander J; Douglas, Steven D et al. (2015) Central and peripheral markers of neurodegeneration and monocyte activation in HIV-associated neurocognitive disorders. J Neurovirol 21:439-48|
|Tebas, Pablo; Spitsin, Sergei; Barrett, Jeffrey S et al. (2015) Reduction of soluble CD163, substance P, programmed death 1 and inflammatory markers: phase 1B trial of aprepitant in HIV-1-infected adults. AIDS 29:931-9|
|McGuire, Jennifer L; Kempen, John H; Localio, Russell et al. (2015) Immune markers predictive of neuropsychiatric symptoms in HIV-infected youth. Clin Vaccine Immunol 22:27-36|
|Tuluc, Florin; Meshki, John; Spitsin, Sergei et al. (2014) HIV infection of macrophages is enhanced in the presence of increased expression of CD163 induced by substance P. J Leukoc Biol 96:143-50|
|McGuire, Jennifer L; Barrett, Jeffrey S; Vezina, Heather E et al. (2014) Adjuvant therapies for HIV-associated neurocognitive disorders. Ann Clin Transl Neurol 1:938-52|
|Schwartz, Lynnae; Spitsin, Sergei V; Meshki, John et al. (2013) Substance P enhances HIV-1 infection in human fetal brain cell cultures expressing full-length neurokinin-1 receptor. J Neurovirol 19:219-27|
|Spitsin, Sergei; Tuluc, Florin; Meshki, John et al. (2013) Analog of somatostatin vapreotide exhibits biological effects in vitro via interaction with neurokinin-1 receptor. Neuroimmunomodulation 20:247-55|
|Spitsin, Sergei; Stevens, Kathleen E; Douglas, Steven D (2013) Expression of substance P, neurokinin-1 receptor and immune markers in the brains of individuals with HIV-associated neuropathology. J Neurol Sci 334:18-23|
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