TW-37, a Senolytic Agent and Inhibitor of KIM-1-Mediated Endocytosis, Reduces KIM-1 Expression, NF-κB-IL-1β Axis, and p16-Mediated Cellular Senescence

Background: Chronic KIM-1 expression is known to be detrimental. Previously, we identified TW-37 as an inhibitor for KIM-1 mediated endocytosis. We discovered KIM-1-mediated endocytosis of palmitic acid-bound albumin leads NLRP3 inflammasome activation, DNA damage response, cell cycle arrest, cellular senescence and inflammatory fibrotic cytokine production. TW-37 is also known as a senolytic which induce cell death on senescent cells. In this study, we tested relatively long-term effects of TW-37 on primary human renal proximal tubular epithelial cells (hRPTECs). Methods: We established primary hRPTECs from a patient’s resected kidney due to a malignancy with a written informed consent. Uninvolved parts of kidneys were cultured on serum-free media containing epidermal growth factor. We seeded 6 x 105cells on day 0 and changed the medium to 10% fetal bovine serum-DMEM (high glucose) containing TW-37 or control DMSO on day 2. We cultured the cells for 8 days (day 2-10) with changing media containing TW-37 or DMSO. KIM-1, NF-κB, IL-1β, p16, caspase-3 and PD-L1 were evaluated by western blotting. Results: Treatment of TW-37 reduced KIM-1 expression. It also reduced NF-κB and IL-1β, probably indicating NF-κB-NLRP3 inflammasome-IL-1β axis was upregulated. In the control p16 was expressed. Treatment of TW-37 reduced expression of p16 but did not increase expression of caspase-3, suggesting that TW-37 may have non-apoptotic anti-senescence effects. Finally, TW-37 reduced PD-L1 expression. Conclusion: TW-37 as known for a senolytic and an endocytosis inhibitor for KIM-1 mediated endocytosis may induce intracellular anti-inflammatory and anti-senescence process by downregulating KIM-1, which can be renoprotective effects. Funding: Private Foundation Support, Government Support – Non-U.S.