Screening for novel senolytic compounds for skin care treatments using machine learning approach.

Summary: Abstract Body: Aging skin accumulates senescent cells that compromise its function and health. Our aim was to discover novel compounds for skin care to improve skin health and delay skin aging by selectively removing senescent cells. Senescent cells are in delicate balance between survival and self-sacrifice. While the cells have a pro-apoptotic microenvironment, they also have so-called senescent cell anti-apoptotic pathways (SCAPs) engaged. Senolytics are compounds that inhibit these SCAPs, inducing apoptosis of the cells. Notably, normal cells remain unaffected as they are not pro-apoptotic. Previous studies have demonstrated the efficacy of the BCL-2 inhibitor Navitoclax leading to selective senescent cell elimination. In our search for novel senolytic compounds we identified BCL-2 inhibitors using machine learning and structure-based molecular screening. After in silico screening of 29299 structures from commercially available natural products, 14 candidates were triaged and tested in an in vitro senolytic assay. Senescent cells were obtained by H2O2 treatment over several days and used to obtain mixtures of normal (70%) and senescent cells (30%). Senescence was quantified by beta-Gal staining combined with flow cytometry. Here we report on the discovery of 6 novel natural compounds* with confirmed senolytic activity on senescent dermal fibroblasts. The candidates significantly (p<0.001) reduced senescent cells by 35% to 80% at 10 μM and were not cytotoxic at this level to normal fibroblasts. We further confirmed the mode of action of our new candidates in an assay using time resolved fluorescence resonance energy transfer (TR-FRET) to quantify inhibition of BCL-2 ligand binding. Finally, we selected one candidate to test on ex vivo human skin explants with 21 days treatment time to evaluate abundance of senescent cells before and after treatment using immunofluorescent staining methods and gene expression analysis. For the ex vivo model we used Navitoclax and quercetin as reference compounds. *identity of the compounds to be disclosed at poster presentation after IP filing Dominik Imfeld¹, Leithe Budel¹, André Fischer¹ 1. R&D Beauty and Care, DSM-Firmenich AG, Kaiseraugst, AG, Switzerland. Translational Studies: Cell and Molecular Biology