Loss of the transforming growth factor‐β effector β2‐Spectrin promotes genomic instability

• DOI: 10.1002/hep.28927
• Publication Date: 2016-11-05T14:59:33Z
• Authors: Jian Chen; Vivek Shukla; Patrizia Farci; Jaclyn Andricovich; Wilma Jogunoori; Lawrence N. Kwong; Lior H. Katz; Kirti Shetty; Asif Rashid; Xiaoping Su; Jon White; Lei Li; Alan Yaoqi Wang; Boris Blechacz; Gottumukkala S. Raju; Marta Davila; Bao‐Ngoc Nguyen; John R. Stroehlein; Junjie Chen; Sang Soo Kim; Heather Levin; Keigo Machida; Hidekazu Tsukamoto; Peter Michaely; Alexandros Tzatsos; Bibhuti Mishra; Richard Amdur; Lopa Mishra
• Keywords: Analysis of Variance; DNA Repair; Ethanol; Fanconi Anemia Complementation Group D2 Protein; Spectrin; Mice, Transgenic; Real-Time Polymerase Chain Reaction; Immunohistochemistry; Genomic Instability; 3. Good health; Mice; Animals, Newborn; Fetal Alcohol Spectrum Disorders; Pregnancy; Animals; Humans; Pregnancy, Animal; Female; Lipid Peroxidation; DNA Damage; Signal Transduction

Exposure to genotoxins such as ethanol‐derived acetaldehyde leads to DNA damage and liver injury and promotes the development of cancer. We report here a major role for the transforming growth factor β/mothers against decapentaplegic homolog 3 adaptor β2‐Spectrin (β2SP, gene Sptbn1) in maintaining genomic stability following alcohol‐induced DNA damage. β2SP supports DNA repair through β2SP‐dependent activation of Fanconi anemia complementation group D2 (Fancd2), a core component of the Fanconi anemia complex. Loss of β2SP leads to decreased Fancd2 levels and sensitizes β2SP mutants to DNA damage by ethanol treatment, leading to phenotypes that closely resemble those observed in animals lacking both aldehyde dehydrogenase 2 and Fancd2 and resemble human fetal alcohol syndrome. Sptbn1‐deficient cells are hypersensitive to DNA crosslinking agents and have defective DNA double‐strand break repair that is rescued by ectopic Fancd2 expression. Moreover, Fancd2 transcription in response to DNA damage/transforming growth factor β stimulation is regulated by the β2SP/mothers against decapentaplegic homolog 3 complex. Conclusion: Dysfunctional transforming growth factor β/β2SP signaling impacts the processing of genotoxic metabolites by altering the Fanconi anemia DNA repair pathway. (Hepatology 2017;65:678‐693)