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. 2004 Feb 1;113(3):370–378. doi: 10.1172/JCI19670

Figure 4.

Figure 4

Impaired mechanotransduction in lamin A/C–deficient cells. (a) Lmna–/– fibroblasts exhibited a significantly higher percentage of propidium iodide–positive cells than did WT cells (2.88% ± 0.49% vs. 1.14% ± 0.14%; P < 0.01, n = 7 [WT], 8 [Lmna–/–]) after 24 hours of strain application (10% at 1 Hz). Differences in unstrained cells were not significant (n = 9 [WT], 10 [Lmna–/–]). (b) Dual labeling with FITC-conjugated annexin V and propidium iodide uptake indicated that apoptotic (A) and necrotic (N) cell fractions are increased in Lmna–/– cells following prolonged strain. Viable cells (V) are propidium iodide–negative and FITC-negative. Top left: WT unstrained control; top right: Lmna–/– unstrained control; bottom left: WT cells after 10% strain for 24 hours; bottom right: Lmna–/– cells after 10% strain for 24 hours. PI, propidium iodide. (c) Lmna–/– (KO) fibroblasts exhibited attenuated mechanical induction of egr-1 and iex-1 after 2 hours and 4 hours of strain (4%) compared with Lmna+/+ cells (WT). Expression of GAPDH was not negatively affected. (d) Cytokine–induced expression of iex-1 was impaired in Lmna–/– cells, while PMA responsiveness remained intact in Lmna–/– cells.