PMID- 36094323 OWN - NLM STAT- MEDLINE DCOM- 20220914 LR - 20220928 IS - 1530-6860 (Electronic) IS - 0892-6638 (Linking) VI - 36 IP - 10 DP - 2022 Oct TI - SMPDL3b modulates radiation-induced DNA damage response in renal podocytes. PG - e22545 LID - 10.1096/fj.202100186RR [doi] AB - The kidneys are radiosensitive and dose-limiting organs for radiotherapy (RT) targeting abdominal and paraspinal tumors. Excessive radiation doses to the kidneys ultimately lead to radiation nephropathy. Our prior work unmasked a novel role for the lipid-modifying enzyme, sphingomyelin phosphodiesterase acid-like 3b (SMPDL3b), in regulating the response of renal podocytes to radiation injury. In this study, we investigated the role of SMPDL3b in DNA double-strand breaks (DSBs) repair in vitro and in vivo. We assessed the kinetics of DSBs recognition and repair along with the ATM pathway and nuclear sphingolipid metabolism in wild-type (WT) and SMPDL3b overexpressing (OE) human podocytes. We also assessed the extent of DNA damage repair in SMPDL3b knock-down (KD) human podocytes, and C57BL6 WT and podocyte-specific SMPDL3b-knock out (KO) mice after radiation injury. We found that SMPDL3b overexpression enhanced DSBs recognition and repair through modulating ATM nuclear shuttling. OE podocytes were protected against radiation-induced apoptosis by increasing the phosphorylation of p53 at serine 15 and attenuating subsequent caspase-3 cleavage. SMPDL3b overexpression prevented radiation-induced alterations in nuclear ceramide-1-phosphate (C1P) and ceramide levels. Interestingly, exogenous C1P pretreatment radiosensitized OE podocytes by delaying ATM nuclear foci formation and DSBs repair. On the other hand, SMPDL3b knock-down, in vitro and in vivo, induced a significant delay in DSBs repair. Additionally, increased activation of apoptosis was induced in podocytes of SMPDL3b-KO mice compared to WT mice at 24 h post-irradiation. Together, our results unravel a novel role for SMPDL3b in radiation-induced DNA damage response. The current work suggests that SMPDL3b modulates nuclear sphingolipid metabolism, ATM nuclear shuttling, and DSBs repair. CI - (c) 2022 Federation of American Societies for Experimental Biology. FAU - Francis, Marina AU - Francis M AUID- ORCID: 0000-0001-7264-8111 AD - Department of Anatomy, Cell Biology, and Physiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. FAU - Ahmad, Anis AU - Ahmad A AD - Department of Radiation Oncology, Miller School of Medicine/Sylvester Cancer Center, University of Miami, Miami, Florida, USA. FAU - Bodgi, Larry AU - Bodgi L AD - Department of Radiation Oncology, American University of Beirut, Beirut, Lebanon. FAU - Azzam, Patrick AU - Azzam P AD - Department of Anatomy, Cell Biology, and Physiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. FAU - Youssef, Tarek AU - Youssef T AD - Department of Anatomy, Cell Biology, and Physiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. FAU - Abou Daher, Alaa AU - Abou Daher A AD - Department of Anatomy, Cell Biology, and Physiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. FAU - Eid, Assaad A AU - Eid AA AUID- ORCID: 0000-0002-3603-0960 AD - Department of Anatomy, Cell Biology, and Physiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. FAU - Fornoni, Alessia AU - Fornoni A AD - Peggy and Harold Katz Family Drug Discovery Center and Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miami, Florida, USA. FAU - Pollack, Alan AU - Pollack A AD - Department of Radiation Oncology, Miller School of Medicine/Sylvester Cancer Center, University of Miami, Miami, Florida, USA. FAU - Marples, Brian AU - Marples B AD - Department of Radiation Oncology, University of Rochester, Rochester, New York, USA. FAU - Zeidan, Youssef H AU - Zeidan YH AD - Department of Anatomy, Cell Biology, and Physiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon. AD - Department of Radiation Oncology, American University of Beirut, Beirut, Lebanon. LA - eng GR - R01 CA227493/CA/NCI NIH HHS/United States GR - R01 DK117599/DK/NIDDK NIH HHS/United States GR - R01 DK104753/DK/NIDDK NIH HHS/United States GR - R01 CA227493/CA/NCI NIH HHS/United States GR - U54 DK083912/DK/NIDDK NIH HHS/United States GR - UM1 DK100846/DK/NIDDK NIH HHS/United States GR - U01 DK116101/DK/NIDDK NIH HHS/United States GR - UL1 TR000460/TR/NCATS NIH HHS/United States PT - Journal Article PL - United States TA - FASEB J JT - FASEB journal : official publication of the Federation of American Societies for Experimental Biology JID - 8804484 RN - 0 (Ceramides) RN - EC 3.1.4.12 (SMPDL3B protein, human) RN - EC 3.1.4.12 (Sphingomyelin Phosphodiesterase) RN - EC 3.1.4.17 (Cyclic Nucleotide Phosphodiesterases, Type 3) RN - EC 3.1.4.17 (sphingomyelinase-like phosphodiesterase 3b, mouse) SB - IM MH - Animals MH - Ceramides/metabolism MH - Cyclic Nucleotide Phosphodiesterases, Type 3 MH - DNA Breaks, Double-Stranded MH - Humans MH - Kidney/metabolism MH - Mice MH - Mice, Inbred C57BL MH - Mice, Knockout MH - *Podocytes/metabolism MH - *Radiation Injuries/genetics/metabolism MH - Sphingomyelin Phosphodiesterase/genetics/metabolism OTO - NOTNLM OT - ATM nuclear shuttling OT - DNA damage response OT - SMPDL3b OT - double-strand breaks OT - nuclear sphingolipids OT - radiation nephropathy OT - radiation podocytopathy OT - sphingolipids EDAT- 2022/09/13 06:00 MHDA- 2022/09/15 06:00 CRDT- 2022/09/12 09:22 PHST- 2022/08/24 00:00 [revised] PHST- 2021/02/03 00:00 [received] PHST- 2022/08/29 00:00 [accepted] PHST- 2022/09/12 09:22 [entrez] PHST- 2022/09/13 06:00 [pubmed] PHST- 2022/09/15 06:00 [medline] AID - 10.1096/fj.202100186RR [doi] PST - ppublish SO - FASEB J. 2022 Oct;36(10):e22545. doi: 10.1096/fj.202100186RR.