%0 Journal Article
%A Schmalz, Michael
%A Liang, Xiao-Xuan
%A Wieser, Ines
%A Gruschel, Caroline
%A Muskalla, Lukas
%A Stöckl, Martin Thomas
%A Nitschke, Roland
%A Linz, Norbert
%A Leitenstorfer, Alfred
%A Vogel, Alfred
%A Ferrando-May, Elisa
%T Dissection of DNA damage and repair pathways in live cells by femtosecond laser microirradiation and free-electron modeling.
%J Proceedings of the National Academy of Sciences of the United States of America
%V 120
%N 25
%@ 0027-8424
%C Washington, DC
%I National Acad. of Sciences
%M DKFZ-2023-01165
%P e2220132120
%D 2023
%Z #LA:W650#
%X Understanding and predicting the outcome of the interaction of light with DNA has a significant impact on the study of DNA repair and radiotherapy. We report on a combination of femtosecond pulsed laser microirradiation at different wavelengths, quantitative imaging, and numerical modeling that yields a comprehensive picture of photon-mediated and free-electron-mediated DNA damage pathways in live cells. Laser irradiation was performed under highly standardized conditions at four wavelengths between 515 nm and 1,030 nm, enabling to study two-photon photochemical and free-electron-mediated DNA damage in situ. We quantitatively assessed cyclobutane pyrimidine dimer (CPD) and γH2AX-specific immunofluorescence signals to calibrate the damage threshold dose at these wavelengths and performed a comparative analysis of the recruitment of DNA repair factors xeroderma pigmentosum complementation group C (XPC) and Nijmegen breakage syndrome 1 (Nbs1). Our results show that two-photon-induced photochemical CPD generation dominates at 515 nm, while electron-mediated damage dominates at wavelengths ≥620 nm. The recruitment analysis revealed a cross talk between nucleotide excision and homologous recombination DNA repair pathways at 515 nm. Numerical simulations predicted electron densities and electron energy spectra, which govern the yield functions of a variety of direct electron-mediated DNA damage pathways and of indirect damage by •OH radicals resulting from laser and electron interactions with water. Combining these data with information on free electron-DNA interactions gained in artificial systems, we provide a conceptual framework for the interpretation of the wavelength dependence of laser-induced DNA damage that may guide the selection of irradiation parameters in studies and applications that require the selective induction of DNA lesions.
%K DNA strand breaks (Other)
%K nonlinear photodamage (Other)
%K oxidative DNA damage (Other)
%K reductive DNA damage (Other)
%K wavelength selectivity (Other)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:37307476
%R 10.1073/pnas.2220132120
%U https://inrepo02.dkfz.de/record/276790