HMGB1 is necessary for the Receptors for Advanced Glycation End‐products (RAGE) inhibition of DNA Double Strand Breaks in trophoblast cells.
- Resource Type
- Article
- Authors
- Kiehl, Joe; Curtis, Katrina; Clarke, Derek; Reynolds, Paul R.; Arroyo, Juan A.
- Source
- FASEB Journal. May2022 Supplement, Vol. 36, pN.PAG-N.PAG. 1p.
- Subject
- Language
- ISSN
- 0892-6638
R2224 --> 829.1 --> Trophoblasts are critical for a successful pregnancy and they mediate important steps such as implantation and delivery. Increased trophoblast DNA double strand breaks (DNA‐DSBs) is implicated in complicated pregnancies. Our laboratory showed a role for increased nuclear placental receptor for advanced glycation end‐products (nRAGE) in DNA‐DSB repair in trophoblasts. HMGB1 protein (nHMGB1) is a nuclear protein that acts as a chromatin‐binding factor involved the regulation of gene transcription that when released extracellularly, is involved in RAGE mediated inflammatory responses. We tested the hypothesis that nHMGB1 correlated with nRAGE availability during DNA‐DSB in trophoblasts. DSBs were induced in human trophoblasts with cigarette smoke extract (CSE). Assessment of HMBG1, Beclin1 (involved in phagocytosis) and Caspase 3 (pro‐apoptotic) were done by immunoblotting. Immunoprecipitation was used to quantify a RAGE and MNR11 complex. Invasion was measured in trophoblast cells in the presence or absence of an HMGB1 inhibitor (Glycyrrhizin; GLY). Decreased trophoblast nHMGB1 (1.8‐fold; p<0.02) was present during DNA‐DSB and this reduction was reversed (4.5‐fold; p<0.02) with GLY treatment. DNA‐DSBs induced a MRN11‐nRAGE complex (1.4‐fold; p<0.03) in trophoblasts and the complex was decreased (2.5‐fold; p<0.05) by GLY co‐treatment. CSE increased Beclin1 (1.9‐fold; p<0.02) and decreased Caspase 3 (2.2‐fold; p<0.02); however, GLY co‐treatment significantly decreased Beclin1 (9.0‐fold p<0.02) while increasing Caspase 3 (1.2‐fold; p<0.04). Compromised trophoblast invasion was improved (7.0‐fold; p<0.02) with GLY treatment. We conclude that CSE causes DNA‐DSBs in trophoblasts and HMGB1 plausibly regulates nRAGE availability at DNA‐DSBs. We further conclude that Beclin1 and Caspase 3 are regulated by HMGB1 inhibition and that HMGB1 targeting could be a factor in regulating trophoblast invasion during DNA‐DSBs. These studies provide a critical initial step in dissecting tobacco‐mediated placental deficiency. [ABSTRACT FROM AUTHOR]