Due to the epidemic spread of HIV in Russia the need for preventive care interventions is becoming increasingly urgent. Because a substantial number of new HIV patients in Russia acquire the infection through heterosexual contact, the existence and availability of effective microbicides is essential for preventing the spread of HIV and improving the life of the younger population. It has been recently established that local applications of gel formulations containing tenofovir (NRTI) could prevent overall 39% of vaginal HIV transmissions. If combined with an efficient non-NRTI (e.g. UC781) the resultant NRTI/NNRTI formulation will likely be more potent in averting the transmission of HIV infection. We have previously established a collaboration with a group of chemists and HIV researchers in Russia (including enzymologists and retrovirologists) that recently synthesized and tested a novel highly efficient family of benzophenone-uracyl (BPU) scaffold-derived NNRTI that can be produced on-site and formulated for topical delivery. These NNRTI were efficient against the wild-type HIV-1 as well as against its mutant forms, including the double mutant (K103N+Y181C) with low indices of resistance. However, BPU are poorly soluble in water essentially limiting their efficacy in tests involving HIV-infected cells. Our previous work has addressed the problem of drug instability and poor solubility using "protected graft copolymer"-based/hydrophobic core (PGC-HC) technology for formulating poorly soluble low molecular mass drugs and peptides including vasoactive intestinal peptide (VIP) for better bioavailability in vivo. We propose to build on the established synergistic interactions with our collaborators in Russia and in industry for testing experimental strategies targeted at creating an efficient formulation for microbicide delivery using PGC technology. The potential of clinical translation of this work is enabled by the excipient status of PGC-HC recently granted by the FDA. Based on the information already derived from a number of pharmacokinetic studies that investigated local delivery of PGC-formulated peptides, PGC-HC copolymer itself does not cause local activation of monocytes or cause damage to the epithelium which makes it an excellent candidate for use as an NNRTI/NRTI carrier. We will use PGC-based formulations in conjunction with a realsitic in vivo system for evaluating the efficacy of microbicides and identifying a lead microbicide formulation. At this time, Bone Marrow Liver Thymic NSG mice (BLT mice), engrafted with CD34+ hematopoietic stem cells ("humanized mice") has emerged as the most advanced small animal model of HIV transmission in humans. We will use BLT/CD34+HSC grafted NSG mice for determining a) the efficacy of PGC-HC/drug cargo transport to lymph nodes using lymph node imaging and b) the influence of NNRTI/NRTI local delivery on p24 titers in infected mice. Our research is greatly facilitated by the strength of our research team and experience in non-invasive monitoring of therapy using non-invasive imaging, developing viral vectors for in vivo gene transfer, and our experience with adoptive transfer in animal models. The proposed research will be performed in collaboration with Dr. Dale Grainer (UMMS), an expert in modeling of human disease in humanized mice and Dr. Celia Schiffer (Director of the Center for AIDS Research (CFAR), UMMS), an expert in HIV drug resistance. We propose to pursue the following Aims:
Aim 1. Optimize and test microbicide formulations containing NNRT/NRTI. We will use human CCR5/CXCR4 reporter cell line and lymphocytoid lines for testing the ability of a PGC-HC formulation (including BPU compounds, either alone or in combination with tenofovir) to block viral infection after cell culture pretreatment with PGC-HC/NNRTI/NRTI mixture components.
Aim 2. Determine the efficacy of topical microbicide in humanized mice. We will use the BLT/NSG model for a) evaluating the transport of PGC-stabilized drug transport to peripheral lymph nodes using high- resolution dual-isotope SPECT/CT imaging and b;) testing the effect of microbicide application prior to HIV experimental infection by following HIV p24 titers. We will then test whether topical application has a cumulative effect on the decrease of HIV transmission and the effect of VIP/PGC-HC additive on HIV infection.
The increase in the rate at which new cases of HIV and AIDS are diagnosed in Russia represents an alarming trend. While new cases reported in the US stabilized at the level of 50,000 per year, the spread of HIV in Russia is widening and affecting a significantly higher segment of the total population with women accounting for more than 50% of new HIV cases. Therefore, there is a need for new preventive care interventions. Because a substantial number of these new HIV-positive patients (40%) acquire the infection through heterosexual contact, the transmission of HIV can potentially be reduced or prevented by using an efficient drug composition that would interfere with the ability of the virus to infect cells inthe vagina or to penetrate into the deep tissue layers. We propose to study such a drug composition that is based on compounds developed through previous research performed in US and Russia. The combined efforts of the investigators will yield a formulation that will be tested in a realistc animal model of human disease (humanized mice). We will determine whether the components of the new drug formulation will stay at the site of application, and whether it will be redistributed inside the body to the lymph nodes that harbor HIV-infected cells. Finally, the efficacy of such topical formulation in preventing HIV infection will be determined in animals using HIV tests.