Development of NLRP3 inhibitors for HIV-associated neuroinflammation

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ABSTRACT The advent of effective combination antiretroviral therapies (cART) has increased the life expectancy for HIV-1 patients, however, these patients are still prone to comorbidities, such as HIV-associatiated neurocognitive disorders (HAND), which affect up to 50% of HIV-infected individuals. Persistent inflammation due to the overactivation of the innate immune system is one of the main underlying causes of HAND. Nucleotide binding domain, leucine rich repeat pyrin domain containing protein-3 (NLRP3) inflammasome has emerged as a druggable target for the management of HIV-1-associated neuropathologies. The NLRP3 inflammasome is shown to be activated in response to a wide array of pathogen- and danger-associated molecular patterns (PAMPs and DAMPs, respectively). A key step in the activation process is a homotypic interaction between the pyrin domains in NLRP3 and an adapter protein, apoptosis-associated speck-like protein containing a CARD (ASC). NLRP3 activation leads to the release of pro-inflammatory cytokines, such as, interleukin-1 (IL-1) and IL-18, causing neuronal pyroptosis and death. Disruption of NLRP3 signaling via small molecules, such as MCC950, is reported to display beneficial effects in the transgenic mouse models. Our recent studies identified a small molecule, AMS-17, that thwarted the NLRP3 activation in N9 microglia both in vitro and in vivo. Subsequent mechanistic analysis revealed that the NLRP3 inhibitory activity of AMS-17 is attributed to its ability to bind to NLRP3 pyrin domain, thus preventing the interaction between NLRP3 and ASC. This proposal is focused on developing AMS-17 analogues with improved biological activity, low toxicity, and high drug-likeness. Aim 1 described in this proposal is focused on the computer-assisted design, synthesis and chemical characterization of AMS-17 analogues. Aim 2 will involve testing of the lead candidates in the humanized mouse model of HAND. The proposed studies are highly significant since they will provide new therapeutic options to minimize HIV-associated neurocognitive dysfunction. The proposal incorporates expertise in the area of synthetic medicinal chemistry (Dr. Kulkarni), biological screening (Dr. Bukrinsky), and computer-assisted drug design (Dr. Adzhubei). It is fully consistent with the goals of this RFA and is expected to define NLRP3 inhibitory compounds working through a novel mechanism different from that of any other currently used drug.