Development of novel therapeutics targeting the identified pathways associated with human longevity

ABSTRACT The overall goal of this U19 is to use genetic variation in human populations linked to extreme phenotypes of healthy aging, centenarians and super-centenarians, to identify rare variants in genes and pathways important for human aging to guide drug development1,2. Project 4 (old Project 3) has focused on developing therapeutics targeting the first identified centenarian rare variants including coding variants in IGF-1R3,4, SIRT65, and ATM, and functional non-coding variants in FOXO3A, SIRT65 and components of the IKK/NF-kB pathway, RelA/p65, NFKB1/p50 and NFKB1a (IkBa)6. During the previous funding period, we developed a novel IKK/NF-kB inhibitor, SR12343, first by in silico screening followed by multiple rounds of Structure Activity Relationships (SAR) using a NF-kB-dependent reporter cell line7. SR12343 was effective in reducing senescence and inflammation and extending healthspan in three different mouse models of aging8. We also demonstrated that a known inhibitor of ATM, KU55933, suppressed NF-kB activity and senescence in cell culture and reduced senescence and inflammation and extended healthspan in vivo9,10. In addition, we recently identified fucoidan, a complex sulfated oligosaccharide from brown seaweed, as able to stimulate the mono–adenosine 5′-diphosphate (ADP)– ribosyltransferase (mADPRT) activity of SIRT6, stimulate SIRT6 dependent DNA repair activity and function as a senotherapeutic. Fucoidan treatment also reduced markers of senescence and extended healthspan in mouse models of accelerated and natural aging. Finally, we demonstrated that a known inhibitor of SMAD3 phosphorylation, SIS3, also reduced senescence in cell culture. These results demonstrate our ability to identify and optimize therapeutics targeting validated variants in genes and pathways identified in human centenarians. Here we propose to expand these efforts to identify, optimize and test compounds targeting key rare variants identified during the previous funding period, including USP35 and UBE3C important for deubiquintination and E3 ubiquitin ligase activities respectively, BLM important for DNA repair and potentially other rare variants to be identified and/or validated by Projects 1, 2 and 3 and Core B. In addition, we will continue to identify and optimize compounds targeting the rare variants in the coding regions of SIRT6 and IGF-1R and the non-coding, regulatory variants in SIRT6, SMAD3 and FOXO3A. The compounds identified targeting the rare variants will be tested for therapeutic activity in collaboration with Project 3 in mouse models of accelerated and natural aging. The Specific Aims of the proposal are: 1) To develop and optimize assays for screening for compounds able to mimic the effect of the functional genetic variants and pathways identified during the previous funding period including functional rare coding variants in IGF-1R, SIRT6, USP35, UBE3C and BLM and non-coding regulatory variants in SMAD3, FOXO3A and SIRT6; and 2) To use the developed assays for screening for compounds able to mimic the effect of the identified functional genetic variants and pathways.