Summary
Peripheral neuropathies are the most frequent neurological complications associated with HIV, within which
HIV sensory neuropathy (HIV-SN) is the most common form, affecting nearly half of HIV/AIDS patients with the
prevalence ranging from 1.2 – 69.4%. HIV-SN frequently manifests with hard-to-manage pain and is often
under-diagnosed and/or under-treated, yet, the large variation in prevalence does not allow for detection of
significant differences in prevalence between HAART-exposed vs. HAART-non-exposed individuals. There is
no specific FDA-approved treatment for HIV-SN. Tat, trans-activator of transcription, a regulatory protein
among the first proteins expressed following HIV infection, is a key activator of HIV transcription and can affect
both HIV infected cells and non-infected neighboring cells via its secretion by infected cells. Although human
studies are lacking, recent animal studies using two models of doxycycline-inducible HIV-1 Tat transgenic
(iTat) mice from our lab and others provided convincing evidence that HIV Tat contributes to the development
of HIV-SN. Therefore, in this proposal, we will further investigate the underlying mechanisms of Tat-associated
SN. Our preliminary study identified potential regulation of Tat of Toll-like receptor (TLR) signaling pathway.
Given the widely accepted involvement of TLR pathway in neuropathic pain and surprising lack of studies
exploring the role of TLR pathway in HIV-SN, we will focus on TLR pathway in Tat-associated SN in this study.
We will take advantage of bioinformatic tools to identify FDA-approved drugs without significant interactions
with existing antiretroviral drugs that could potentially reverse Tat-induced changes in TLR pathway, and then
test their effectiveness in treating Tat-associated SN in vivo. Altogether, we hypothesize that TLR signaling
pathway is involved in the development of HIV-Tat-associated SN and it is possible to identify potential
treatment for HIV-SN by examining existing drugs via a combined bioinformatics and pre-clinical model
approach. This will be tested through 2 Specific Aims. Aim 1 will determine the contribution of Tollip (a key
regulator of TLR pathway)-regulated TLR pathways in HIV Tat-associated SN using genetically modified
animal models in combination with behavioral and physiological tests. Aim 2 will identify potential drugs for
HIV-SN by targeting TLR pathway via a combined bioinformatics and pre-clinical model approach. If
successful, we will fill in the knowledge gaps regarding Tat-associated SN and TLRs’ role in HIV-SN. Our
comprehensive combination drug discovery strategy will help identify potential drugs for HIV-SN, which can be
further tested in other animal models before clinical assessment. Throughout the process, we will prioritize
drug candidates that are mechanistically-sound, and potentially easily accessible to all patients.