Fig. 3.

ER morphology and ER-mitochondria contacts under ER stress conditions in human THP-1 monocytes. Alterations in width of ER and in the number of ER-mitochondria contacts due to ER stress were monitored by TEM in human THP-1 monocytes treated with 5 or 10 μg/mL TM for 8 h and compared with untreated cells. (A) Representative images of dilated ER (arrowhead); (B) ER width expressed in nm; (C) Representative images of ER-mitochondria contacts (arrow); (D) Number of ER-mitochondria contacts (≤ 100 nm) normalized to mitochondria number; (E) Number of close ER-mitochondria contacts (≤ 15 nm) normalized to mitochondria number. Results represent the mean ± SEM of 4–5 images per cell obtained from 5 cells analyzed per condition. Statistical significance between control (untreated cells) and TM-treated cells was determined using the one-way ANOVA test, followed by the Dunnett’s post hoc test: *p < 0.05, **p < 0.01, *** p < 0.001