Neuroinflammation has been recognized as an essential player in the pathogenesis of Alzheimer’s disease (AD). Recently, the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome, a multimeric protein complex that tightly regulates the innate immune responses, has been suggested with critical roles in AD development and progression. Dysregulation of the NLRP3 inflammasome is responsible for the over production of pro-inflammatory interleukin (IL)-1β and IL-18, ultimately leading to inflammatory responses and cell death. Thus, NLRP3 inflammasome represents an attractive drug target for AD and offers promise to provide effective disease modifying potential. Over the past several years, our team has successfully developed novel small molecule NLRP3 inflammasome selective inhibitors (NSIs). We originally reported NSIs with sulfonamide containing chemical scaffolds, and have established a small molecule library containing > 200 compounds with various biological characteristics. Proof of concept studies of our 1st generation lead NSI in transgenic AD mouse models demonstrated target engagement and in vivo efficacy to reduce neuroinflammation and improve cognitive functions. Our recent medicinal chemistry campaign led to the identification of new lead NSIs with significantly improved potency and binding affinity. Furthermore, our accumulated structure-activity relationship (SAR) studies have identified key structural features of the scaffolds for further optimization. The central hypothesis of this proposal is that structural optimization of the current two preclinical lead NSIs will be achieved by designing new viable analogs and isolating potent and orally available NSIs with improved pharmacokinetic (PK) properties (Aim 1), and that pharmacological suppression of the NLRP3 inflammasome by our NSIs will mitigate neuroinflammation and improve cognitive functions in preclinical AD animal models (Aim 2), which will be further evaluated by preclinical Investigational New Drug (IND)-enabling studies (Aim 3) to advance to clinical studies. For our hypothesis, the goal of this application is to accomplish preclinical IND-enabling studies on at least one candidate NSI and prepare for a meeting with the FDA and subsequent IND filing. Three aims are proposed to achieve our objectives. In Aim 1, new analogs of the lead NSIs will be designed, synthesized and biologically characterized to build a dynamic drug discovery and development pipeline. In Aim 2, selected NSIs from aim 1 will be tested for PK/PD properties in various animal models including AD mouse models. In aim 3, the top candidate NSI identified from Aim 2 will be subjected to IND-enabling studies including GMP production, GLP toxicology studies in rodents and dogs, and oral formulation development to prepare for IND filing and clinical trials. The proposed research is highly significant because we are developing a novel class of NSIs that will offer great promise to provide novel and effective therapeutics for AD, a devastating neurodegenerative disorder without cure currently.

NLRP3 inflammasome has recently been suggested to play important roles in multiple human diseases including Alzheimer’s disease (AD). The research proposed in this application will conduct structural optimization of our newly identified lead NLRP3 inflammasome inhibitors to develop a candidate to accomplish IND-enabling studies as potential AD therapeutic agent; therefore it is relevant to public health.