Fig. 4. Decreased stretch-induced Ca²⁺ response and stiffness in fascicles from tenocyte-targeted Piezo1 knockout mice.

a, Generation of Scx-creERT2;Piezo1^fl/fl mice expressing CreERT2 under the Scleraxis promoter. Tamoxifen injections were performed at P1-P3 and the analysis was carried out between P50 and P95. b, Reduced Piezo1 expression in tail tendon fascicles from Piezo1cKO mice (Scx-creERT2;Piezo1^fl/fl, n=17 mice) compared to their wild-type littermates (Piezo1^fl/fl, n=15 mice). Anxa5 was used as reference gene. Unpaired Student’s t-test. c, The overall stretch-induced Ca²⁺ response is reduced in fascicles from 7-11-week-old Piezo1cKO mice (n=9 mice) compared to wild-type littermate controls (n=6 mice), 6 fascicles were tested per mouse. d, Corresponding single cell analysis shows that tenocytes in fascicles from Piezo1cKO mice exhibit a reduced amplitude of the stretch-induced Ca²⁺ signals and a reduced % of responsive cells. e, Ramp-to-failure tests show a decreased stiffness of fascicles from 10-13-week-old Piezo1cKO mice (n=14 mice) compared to wild-type littermate controls (n=12 mice, 6 fascicles tested per mouse). Unless indicated otherwise, statistics was performed with linear mixed effects models (mouse ID as random effect and litter as fixed effect). Replicates are biological. Data are means±SEM.