Aligned collagen fiber film promotes nuclear curvature and DNA repair factor mislocalization. (A) AFM image of long-range alignment of collagen fibrils. (B) Both immunofluorescence and AFM probing confirm cells elongate only along the collagen fibers. (C) Immunofluorescent image and quantitation of DNA repair factor KU70 in fixed cells after 6 h seeding. Ruptured nuclei (arrow in image) show high cytoplasmic/nuclear intensity ratio (plot) and are more elongated than nonruptured nuclei (low cytoplasmic/nuclear ratio) at 6 and 12 h. n > 15 cells per point in three experiments analyzing >100 cells per experiment. (D) As nuclear AR increases, normal maximum curvature Increases, and circularity decreases. Our model predicts the trend. n = 46. (E) In nonruptured nuclei, cGAS is cytoplasmic, but cGAS enriches at high-curvature sites of ruptured nuclei as validated by higher cytoplasmic/nuclear GFP-KU70 (bar graph). n > 10 cells. *, P < 0.05. Bars, 10 µm. All data are presented as mean ± SEM.