Fig. 6: 20 nm ER-mitochondrial distance and mitochondrial Ca²⁺ are disrupted in astrocytes from Parkinson’s disease patients.

Representative traces and quantifications of raw (a, b) and baseline-normalized (c, d) ATP (100 µM)-induced Ca²⁺ transients in hiA from healthy subjects (Ctr) and from LRRK2^G2019S patients (PD). Data are expressed as mean ± SEM of basal 530/475 ratio (Basal) and peak of the response (Peak) from 56–63 cells from three independent experiments. Representative images and quantification of fluorescence SPLICS-Short (e), 20nm-SPLICS (f) and SPLICS-Long (g) transfected in hiA from healthy subjects (Ctr) and from LRRK2^G2019S patients (PD). Data are expressed as mean ± SEM of GFP area normalized to cell area from n = 19–22 cells from at least three independent transfections. Unpaired two-tailed Student’s t-test, ***p-value < 0.001; ****p-value < 0.0001. h Representative TEM micrographs and quantifications of the ER-OMM distance of hiA from healthy subjects (Ctr) and from LRRK2^G2019S patients (PD). Arrows indicate ER membrane adjacent to mitochondria. Scale bar = 500 nm. Data are mean ± SEM from 72–88 individual contact sites from 28 (Ctr) or 20 (PD) slices per genotype. Unpaired two-tailed Student’s t-test, ****p-value < 0.0001.