TW-37, an Inhibitor of KIM-1-Mediated Endocytosis, Inhibits Cellular Senescence and Related Phenomena

Background: Chronic expression of KIM-1 is known to be detrimental to the kidney. Previously, we identified TW-37 as an inhibitor of KIM-1-mediated endocytosis. We then found that KIM-1-mediated endocytosis of palmitate-bound albumin leads to activation of the NLRP3 inflammasome, DNA damage response, cell cycle arrest, cellular senescence, and production of inflammatory and fibrotic cytokines TW-37 also induces cell death in senescent cells It is also known as a senescent cell eliminator. In this study, we investigated the relatively long-term effects of TW-37 on primary cultured human renal proximal tubular epithelial cells (hRPTECs). Methods: Primary cultured hRPTECs were established from kidneys of patients resected for malignancy under written explanation and consent (approved by the Ethics Review Committee of Tokyo Medical and Dental University School of Medicine: M2022-005). Kidneys from non-malignant portions were cultured in serum-free medium containing epidermal growth factor. Established cells were seeded in 6 × 105 6-well plates on day 0 and changed to 10% FBS-DMEM containing TW-37 or control DMSO on day 2. Cultures were continued for 8 days from day 2 to day 10, changing medium containing TW-37 or DMSO. KIM-1, NF-κB, IL-1β, p16, caspase-3 and PD-L1 were evaluated by Western blotting. Megalin expression was evaluated by immunofluorescence. Results: The expression of KIM-1 was decreased by TW-37 treatment. NF-κB and IL-1β were also decreased, possibly suppressing the NF-κB-NLRP3-IL-1β pathway. While p16 was expressed in control cells, TW-37 treatment decreased p16 expression but did not increase caspase-3 expression, suggesting that TW-37 may have a nonapoptotic anti-aging effect. And TW-37 decreased PD-L1 expression. Megalin expression was not changed by TW-37 treatment, suggesting that cells kept differentiation. Conclusion: In the long term, TW-37 may induce anti-inflammatory and anti-aging processes in cells by suppressing KIM-1, resulting in renoprotective effects. Funding: Private Foundation Support, Government Support – Non-U.S.