Ed when chondrocytes have been treated with Piezo1-targeting miRNA (50 , 6/12 cells), in comparison with these cells treated together with the scrambled miRNA (19/22 cells, Fisher’s precise test, p=0.04) (Figure 4A). These data show that knocking down the levels in the PIEZO1 channel reduces the likelihood of evoking deflection-gated currents. When the stimulus-response data was plotted, the PIEZO1 knockdown cells showed a tendency for lowered mechanoelectrical transduction, in comparison with handle cells (Figure 4B). TRPV4 has been proposed to play a role in chondrocyte mechanoelectrical transduction (Clark et al., 2010; Leddy et al., 2014; Dunn et al., 2013). We for that reason studied deflection-gatedRocio Servin-Vences et al. eLife 2017;six:e21074. DOI: ten.7554/eLife.six ofResearch articleBiophysics and Structural Biology Cell BiologyACurrent amplitude (pA)BDeflection treshold (nm)Chondrocytes (24) Dedifferentiated (15)1024 256 64 16 nd ho CDeflection (nm)C70 mmHgDNormalized responseChondrocytes (12) Dedifferentiated (13)80 40 pA 1s 70 mmHg40 pA 1sP50 = 87.1 six.0 mmHg P50 = 78.7 7.four mmHg0 0 50 150Pressure (mmHg)Figure 3. Chondrocytes and dedifferentiated cells display distinct mechanosenstivity to substrate deflections. (A) Stimulus-response graph of deflection-gated currents in chondrocytes (red circles) and dedifferentiated cells (cyan squares). Measurements from a person cell were binned based on stimulus size and existing amplitudes were averaged inside each bin, then across cells, information are displayed as mean s.e.m. For stimuli among one 1405-10-3 manufacturer hundred and 10050 nm, the dedifferentiated cells exhibit substantially larger currents. (Mann-Whitney test p=0.02 and p=0.004, respectively, n = 24 chondrocytes and 15 dedifferentiated cells.) Also, an ordinary two-way ANOVA indicates that the cell-types differ in their overall response (p=0.03). (B) Chondrocytes and dedifferentiated cells show distinct deflection thresholds to substrate deflections. A threshold was calculated by averaging the smallest deflection that resulted in channel gating, for each cell. The threshold for chondrocytes, 252 68 (mean s.e.m., n = 24) was significantly higher than that calculated for dedifferentiated cells 59 13 (imply s.e.m., n = 15) (Mann-Whitney, p=0.028). (C) Representative traces from HSPC recordings of stretchactivated currents from outside-out patches pulled from chondrocytes (upper panel) and dedifferentiated cells (decrease panel). (D) Stimulus-response curve of pressure-gated currents in chondrocytes (red) and dedifferentiated cells (cyan), normalized to maximal amplitude measured for each sample. (Data are displayed as mean s.e.m., n = 12 chondrocytes, 13 dedifferentiated cells.). DOI: ten.7554/eLife.21074.007 The following supply data is accessible for figure three: Supply data 1. Statistical comparison of mechanoelectrical transduction currents, chondrocytes vs dedifferentiated cells. DOI: ten.7554/eLife.21074.Rocio Servin-Vences et al. eLife 2017;6:e21074. DOI: ten.7554/eLife.Dediff7 ofResearch articleBiophysics and Structural Biology Cell BiologyA1. 66BNo resp RespCurrent amplitude (pA)150Fraction of cellsScrambled (22) Piezo1-KD (12)0.50 pA 400 ms-/–K DW TedCCurrent amplitude (pA)one hundred 80 60 40 20 0 1 ten one hundred Deflection (nm)50 pA 400 msTr pv four Pi ez Tr o1 pv -K four DblSc ra mPi ezo-/-0 1 ten one hundred Deflection (nm)DCurrent amplitude (pA)WT (27) Trpv4 -/-(13)100 80 60 40 20 (��)-Darifenacin Protocol 0Trpv4 -/- Piezo1-KD (11)50 pA 400 ms10 one hundred Deflection (nm)EATP Yoda1 ten 10 GSK101 50nM Basal ATP ten Yoda1 ten.