EMBO/SourceData huggingface dataset:
Figure 1B) Percentage specific binding of [3H]dofetilide to the hERG channel after 6 minutes of dissociation induced by 10 µM dofetilide in the absence (control) or presence of 10 and 50 µM of LUF compounds. The specific binding of [3H]dofetilide in the absence of test compounds was set as Bcontrol, while the specific binding in their presence was set as B. * = p < 0.05 vs control; N: 3-4.C) Representative traces of hERG activation (left), inactivation (middle), and deactivation (right) measured in HEK293 hERG cells under baseline conditions (black) and in the presence of 3 µM LUF7346 (red). Insets: voltage clamp protocols.D) Steady-state activation (empty symbols) and inactivation (filled symbols) curves for IKr under baseline conditions (black) and in the presence of 3 µM LUF7346 (red). The corresponding Boltzmann's fittings are superimposed to data points.* = p < 0.05 vs baseline. N: 11-14.E) Plot of the time constants (τ) of deactivation derived from biexponential fittings under baseline conditions (black) and in the presence of 3 µM LUF7346 (red). * = p < 0.05 vs respective baseline. N: 8.
Figure 2B) Baseline QT interval (top), baseline RR interval (middle), and baseline QT interval corrected with the Bazett's formula (bottom). Bar graphs are divided by isogenic pairs (LQT1R594Q and JLNSR594Q, left; LQT2corr, LQT2N996I, hESCWT, and hESC-LQT2N996I, middle; LQT1corr and LQT1R190Q, right) and in each graph the unrelated WT is shown as a comparison. N: 17-53. * = p<0.05. The colour of the symbol indicates comparisons and relative statistical significance.C) Representative traces of IKr steady state activation in WT hiPSC-CMs in Tyrode (left), in the presence of 5 µM LUF7346 (middle) and after the application of 5 µM E4031 to selectively block IKr (right). Inset: voltage clamp protocol.D) Average I/V relationships (left) and steady-state activation curves with superimposed Boltzmann's fittings (right) under baseline conditions (black) and in the presence of 5 µM LUF7346 (red). * = p<0.05. N: 19.E) Plot of the time constants (τ) of deactivation derived from biexponential fits (left) and representative examples (right) under baseline conditions (black) and in the presence of 3 µM LUF7346 (red). * = p<0.05. N: 17-21.
Figure 3A) Representative MEA trace (left) showing the effect of increasing concentrations of LUF7346 on FP contour, measured in LQT2N996I-CMs. Average data (right) showing the effect of LUF7346 on QT interval duration relative to baseline in CMs derived from all the hiPSC lines used in this study. * = p<0.05 vs baseline. Colour in the heatmap defines the magnitude of QT shortening (blue) after treatment with increasing concentrations of LUF7346. N: 7-14.B) Representative AP from LQT2corr-, LQT2N996I-, LQT1corr-, and LQT1R190Q-CMs paced at 1 Hz, under baseline conditions (black) and after application of increasing concentrations of LUF7346 (colour-code is shown).C) Effect of LUF7346 on APD90, APD70, and APD50, measured in LQT2corr- (blue), LQT2N996I- (green), LQT1corr- (purple), LQT1R190Q- (dark blue) paced at 1 Hz; * = p<0.05 vs baseline. The colour of the asterisk indicates comparisons and respective statistical significance. ° = p<0.05 vs the genetically-matched corrected control. # = p<0.05 LQT1corr vs LQT2corr. N: 12-15.D) Effect of LUF7346 on APA and Ediast, measured in LQT2corr- (blue), LQT2N996I- (green), LQT1corr- (purple), and LQT1R190Q-CMs (dark blue) paced at 1 Hz. N: 12-15.
Figure 4A) Representative MEA trace (left) showing the effect of 100 nM AST and increasing concentrations of LUF7346 in the presence of AST on FP contour, measured in LQT1R594Q-CMs. Average data (right) of the effect of AST and LUF7346 in the presence of AST on QT interval duration compared to baseline in CMs derived from all the hiPSC lines used in this study. * = p<0.05 vs respective baseline. ° = p<0.05 vs AST. Colour in the heatmap defines the magnitude of QT prolongation (red) and QT shortening (blue), respectively, after treatment with AST and with increasing concentrations of LUF7346 in the presence of AST. N: 5-10.B) Representative AP from WT-, LQT1R594Q- and JLNSR594Q-CMs, paced at 1 Hz, under baseline conditions (black), after application of 100 nM AST (red), and after addition of increasing concentrations of LUF7346 in the presence of AST (colour-code is shown).C) Effect of AST and LUF7346 in the presence of AST on APD90, APD70, and APD50 in WT- (grey), LQT1R594Q- (red) and JLNSR594Q-CMs (black) paced at 1 Hz. * = p<0.05 vs respective baseline; ° = p<0.05 vs AST. N: 11-16.D) Effect of AST and LUF7346 in the presence of AST on APA and Ediast in WT- (grey), LQT1R594Q- (red) and JLNSR594Q-CMs (black) paced at 1 Hz. N: 11-16.
Figure 5A: Representative AP traces measured in JLNSR594Q-CMs paced at 1 Hz, under baseline conditions (black) and after application of either AST alone (red), AST+LUF7346 3 µM (green) and AST+LUF7346 5 µM (blue).B: STV values calculated on spontaneously beating hiPSC-CM clusters over 30 consecutive beats as measured with MEA. N = 7-24. * = p<0.05 vs respective isogenic pair.C: STV changes (left) and representative examples of QT interval oscillations plotted over 30 consecutive beats (right) in the presence of AST and AST+LUF7346 20 µM. * = p<0.05 vs Baseline. ° = p<0.05 vs AST. N = 7-24.
Figure 1A-B. SH-SY5Y cells and primary cortical neurons were treated with 1 μM α-syn fibrils (A) or monomers (B) for 30 min. The cells were lysed and Western blot was performed with the indicated antibodies. Images are representative of three independent experiments (n=3). *** P < 0.001, ** P < 0.01 compared to PBS, unpaired t-test.C. Frontal cortices of A53T α-syn heterozygous transgenic mice and control mice at the age of 9 months (old) or 2 months (young) were lysed and Western blot was performed with the indicated antibodies (n=3). *** P < 0.001 compared to WT, unpaired t-test.FcγRIIB KD SH-SY5Y cells were treated with 1 μM α-syn fibrils for 30 min. The cells were lysed and Western blot was performed with the indicated antibodies. Images are representative of three independent experiments (n=3). *** P < 0.001, ** P < 0.01, * P < 0.05 compared to PBS, one-way ANOVA.SHP-1 KD SH-SY5Y cells were treated with 1 μM α-syn fibrils for 30 min. The cells were lysed and Western blot was performed with the indicated antibodies. Images are representative of three independent experiments (n=3). *** P < 0.001, ** P < 0.01, * P < 0.05 compared to PBS, one-way ANOVA.SHP-2 KD SH-SY5Y cells were treated with 1 μM α-syn fibrils for 30 min. The cells were lysed and Western blot was performed with the indicated antibodies. Images are representative of three independent experiments (n=3). *** P < 0.001, ** P < 0.01, * P < 0.05 compared to PBS, one-way ANOVA.SH-SY5Y cells with 20 μM NSC87877, 10 μM SSG and 1 μM PHPS-1 were treated with 1 μM α-syn fibrils for 30 min. The cells were lysed and Western blot was performed with the indicated antibodies. Images are representative of three independent experiments (n=3). *** P < 0.001, ** P < 0.01, * P < 0.05 compared to PBS, one-way ANOVA.
Figure 2SH-SY5Y cells were cocultured with differentiated A53T α-syn-EGFP OE SH-SY5Y cells in the presence of 5 μM saracatinib (sara) or 10 μM SKI-1 for 12 h. The cells in the lower chamber were fixed and immunostained with anti-EGFP antibody. The intensity was analyzed. Values were derived from four independent experiments (n=4). *** P < 0.001 against PBS, one-way ANOVA.NT, c-src KD #1 and #2 SH-SY5Y cells were cocultured with differentiated A53T α-syn-EGFP OE SH-SY5Y cells for 12 h, and then fixed and immunostained with anti-EGFP antibody. Values were derived from four independent experiments (n=4). *** P < 0.001 compared to NT cells, one-way ANOVA, D. primary cortical neurons were cocultured with differentiated A53T α-syn-EGFP OE SH-SY5Y cells in the presence of 5 μM saracatinib (sara) or 10 μM SKI-1 for 12 h. The cells in the lower chamber were fixed and immunostained with anti-EGFP antibody. The intensity was analyzed. Values were derived from four independent experiments (n=4). *** P < 0.001 against PBS, one-way ANOVA., E. primary cortical neurons downregulating c-src were cocultured with differentiated A53T α-syn-EGFP OE SH-SY5Y cells for 12 h, and then fixed and immunostained with anti-EGFP antibody. Values were derived from four independent experiments (n=4). *** P < 0.001 compared to NT cells one-way ANOVA unpaired t-testSH-SY5Y cells were transfected with plasmids of WT c-src, Y529F c-src (kinase active), or K297M c-src (kinase dead) tagged with EGFP. After 1 day, the cells were cocultured with differentiated α-syn OE SH-SY5Y cells for 12 h and then fixed and immunostained with anti-α-syn antibody. The intensity was analyzed. Values were derived from three independent experiments (n=3). *** P < 0.001, * P < 0.05 compared to mock positive cells, one-way ANOVA.G. FcγRIIB KD SH-SY5Y cells were transfected with plasmids of WT c-src, Y529F c-src (kinase active), or K297M c-src (kinase dead) tagged with EGFP. After 1 day, the cells were cocultured with differentiated α-syn OE SH-SY5Y cells for 12 h and then fixed and immunostained with anti-α-syn antibody. The intensity was analyzed. Values were derived from three independent experiments (n=3). *** P < 0.001, * P < 0.05 compared to mock positive cells, one-way ANOVA.
Figure 3B. A53T α-syn-EGFP and A53T α-syn-mCherry OE SH-SY5Y cells were cocultured in the presence of 5 μM saracatinib (sara) or 10 μM SKI-1, respectively, with 50 μM RA for 5 days.C. NT or c-src KD #1 or #2 /A53T α-syn-EGFP and A53T α-syn-mCherry OE SH-SY5Y cells were cocultured with 50 μM RA for 5 days. The samples were observed under confocal microscopy, and the number of cells containing double fluorescence labeled puncta were analyzed. Values were derived from five independent experiments (n=5). *** P < 0.001 compared to PBS or NT cells, one-way ANOVA.
Figure 4A. Differentiated A53T α-syn-EGFP OE SH-SY5Y cells were incubated with 5 μM saracatinib (sara) or 10 μM SKI-1 for 12 h.B. Differentiated NT, c-src KD #1 or c-src KD#2/A53T α-syn-EGFP OE SH-SY5Y cells were cultured 12 h. Levels of α-syn in culture media were then measured using ELISA. Values were derived from three independent experiments (n=3). *** P < 0.001, ** P < 0.01 compared to control, one-way ANOVA.D. SH-SY5Y cells in the lower chamber were cocultured with differentiated NT, c-src KD #1 or c-src KD #2/ A53T α-syn-EGFP OE SH-SY5Y cells for 12 h. The cells in the lower chamber were immunostained with anti-EGFP antibody. The intensity was analyzed. Values were derived from five independent experiments (n=5). *** P < 0.001 compared to NT cells, one-way ANOVA.E. Differentiated A53T α-syn-EGFP OE SH-SY5Y cells were incubated with 5 μM saracatinib (sara) or 10 μM SKI-1 in the presence of DMSO or 50 μM bafilomycin A1 (BafA) for 12 h.Differentiated NT and c-src KD/A53T α-syn-EGFP OE SH-SY5Y cells were incubated with 50 μM BafA for 12 h. Western blot was performed. Data are representative of three independent experiments (n=3). *** P < 0.001, ** P < 0.01, * P < 0.05, one-way ANOVA.G. NT and c-src KD primary neurons were incubated with 50 μM BafA for 12 h. Western blot was performed. Data are representative of three independent experiments (n=3). *** P < 0.001, ** P < 0.01, * P < 0.05, one-way ANOVA.H. SH-SY5Y cells were cocultured with differentiated A53T α-syn-EGFP OE SH-SY5Y cells in the presence of DMSO or 50 μM BafA for 12 h. The cells were immunostained with anti-EGFP antibody. The intensity was analyzed. Values were derived from three independent experiments (n=3). ** P < 0.01, one-way ANOVA.
Figure 5SH-SY5Y cells in the presence of 5 μM saracatinib, 10 μM SKI-1 were incubated with 1 μM α-syn fibrils for 30 min and these cells were further incubated with 50 nM BODIPY FL C5-LacCer and 2.5 μg/ml rhodamine-conjugated transferrin for 20 min. The cells were fixed and observed under confocal microscopy. The intensity was analyzed. Values were derived from five independent experiments (n=5). *** P< 0.001 compared to control, one-way ANOVA.B. NT, c-src KD #1 or c-src KD #2 SH-SY5Y cells were incubated with 1 μM α-syn fibrils for 30 min and these cells were further incubated with 50 nM BODIPY FL C5-LacCer and 2.5 μg/ml rhodamine-conjugated transferrin for 20 min. The cells were fixed and observed under confocal microscopy. The intensity was analyzed. Values were derived from five independent experiments (n=5). *** P< 0.001 compared to control, one-way ANOVA.
Figure 6Two to three-month-old hemizygous M83 mice were injected into the striatum with sterile PBS or 10 μg of recombinant α-syn fibrils. The mice were treated with saracatinib at 10 mg/kg/day by oral gavage for 4 weeks. B. Fixed brain tissues containing the frontal cortex and the striatum were lysed. Western blot was performed with indicated antibodies. Values were derived from three individual mice (n=3).Two to three-month-old hemizygous M83 mice were injected into the striatum with sterile PBS or 10 μg of recombinant α-syn fibrils. The mice were treated with saracatinib at 10 mg/kg/day by oral gavage for 4 weeks. C. Immunohistochemistry of pSer129 α-syn was performed. Arrow indicates pSer129 α-syn positive inclusion. Scale bar indicates 50 μm. D. Scoring of pSer129 immunoreactivity in the cortex and the striatum of both regions. Values were derived from eight individual mice (n=8). *** P < 0.001, ** P < 0.01, * P < 0.05 compared to PBS group, unpaired t-test. Data are expressed as mean ± SEM.
Figure 7A. Immunohistochemistry of GFAP was performed. GFAP intensities in the cortex and the striatum were analyzed. Values were derived from three individual mice (n=3). *** P < 0.001, ** P < 0.01, * P < 0.05, one-way ANOVA.B. Immunohistochemistry of IBA-1 and MHC Class II were performed. Arrow indicates MHC class II positive cells. Numbers of MCH class II positive cells in the cortex and the striatum were analyzed. Values were derived from three individual mice (n=3). *** P < 0.001, ** P < 0.01, one-way ANOVA.
Figure 2(A) MITOL-HA did not move to peroxisomes, but was rather retained on mitochondria even after CCCP treatment in HeLa cells lacking endogenous Parkin. Wild-type HeLa cells or HeLa cells stably expressing GFP-Parkin were transfected with MITOL-HA, treated with 15 µM CCCP for 3 hours, and then subjected to immunocytochemistry with anti-HA and anti-Tom20 antibodies. Higher magnification images of the boxed regions are shown in the small panel. Scale bars, 10 µm.(B) Correlation statistics for the localization of MITOL-HA and Tom20 in the absence or presence of GFP-Parkin. Dots indicate individual Pearson correlation coefficient data points. In the box-plots, the center lines indicate the medians, the box limits indicate the 25th and 75th percentiles as determined in the R software package, and the whiskers extend 1.5 times the interquartile range from the 25th and 75th percentiles. Means and the number of samples are shown on the box and X-axis, respectively. Statistical significance was calculated using a one-tailed Welch's t-test.(C) MITOL was not degraded following mitochondrial depolarization. HeLa cells stably expressing 3Flag-MITOL were transfected with a GFP-Parkin plasmid or the pEGFP-C1 vector, treated with 15 µM CCCP +/- 10 µM MG132 for 3 hours, and then immunoblotted with anti-Flag, anti-ubiquitin, and anti-tubulin antibodies. Black arrowheads indicate 3Flag-MITOL in the upper panel and mono-ubiquitin in the middle panel, respectively.(D) The total cellular amount of MITOL was not dramatically reduced following extended valinomycin treatment. Immunoblotting combined with fractionation analysis showed that Mitofusin2 (MFN2) underwent rapid degradation within 3 hours of valinomycin treatment, in particular in the 3,000 g pellet (mitochondria-rich fractions). Cytochrome c oxidase subunit 2 (MTCO2, inner mitochondrial protein) was significantly reduced at 24 hours 10 μM valinomycin treatment. In contrast to those two proteins, MITOL degradation was minimal. Note that the chemical apoptosis inhibitor ZVAD-FMK (10 μM) was added to cells along with valinomycin to prevent cell death.(E) Quantification of 3Flag-MITOL, MFN2, and MTCO2 protein levels in the PNS and 3,000 g pellet fraction following 10 µM valinomycin + ZVAD-FMK treatment at the indicated times. Data represent the mean fold change ± s.e.m relative to untreated samples in three biological replicates.(F) Pre-existing MITOL on mitochondria moves to peroxisomes following CCCP treatment. Following doxycycline treatment for 3 hours to induce MITOL expression, cells were washed with fresh medium to stop the synthesis of new MITOL. After treatment with or without CCCP for more than 3 hours, cells were immunostained using anti-Flag, anti-Pex14 (peroxisomal membrane protein), and anti-Hsp60 antibodies. Higher magnification images of the boxed regions are shown in the bottom panel. Scale bars, 10 µm.
Figure 3(A) Wild-type or PINK1 knock out (KO) HeLa cells were transfected with GFP-Parkin wild-type or the C431S mutant, treated with 15 µM CCCP, and then immuno-stained with anti-Flag and anti-catalase antibodies. Wild-type Parkin, but not the catalytically inactive Parkin (C431S) mutant, mediated 3Flag-MITOL translocation to peroxisomes following mitophagy stimulation. In PINK1 KO HeLa cells, the redistribution of MITOL to peroxisomes was not observed even in the presence of wild-type Parkin when mitochondria were damaged. Higher magnification images of the boxed regions are shown in the small panel. Scale bars, 10 µm. Arrowheads indicate representative examples of MITOL-peroxisome co-localization observed only in the presence of wild-type Parkin.(B) The redistribution of MITOL from mitochondria to peroxisomes does not require its own E3 activity. The E3-inactive MITOL Cys65Ser/Cys68Ser (CS) and H43W mutants were transfected into HeLa cells stably expressing HA-Parkin, treated with 15 µM CCCP, and then subjected to immunocytochemistry with anti-Flag and anti-catalase antibodies. After 3 hours of CCCP treatment, both the CS and H43W mutants co-localized with catalase. Higher magnification images of the boxed regions are shown in the small panel. Scale bars, 10 µm. Arrowheads indicate representative examples of 3Flag-MITOL co-localization with catalase.(C) Correlation statistics for the localization of 3Flag-MITOL and catalase in the presence of GFP-Parkin wild-type or an inactive C431S mutant. Dots indicate individual Pearson correlation coefficient data points. In the box-plots, the center lines indicate the medians, the box limits indicate the 25th and 75th percentiles as determined in the R software package, and the whiskers extend 1.5 times the interquartile range from the 25th and 75th percentiles. Means and the number of samples are shown on the box and X-axis, respectively. Statistical significance was calculated using a one-tailed Welch's t-test. MITOL overlapped with catalase only in the presence of wild-type Parkin in wild-type HeLa cells. In PINK1 knockout (KO) HeLa cells, wild-type Parkin was unable to induce the peroxisomal translocation of MITOL.(D) Correlation statistics for the localization of 3Flag-MITOL wild-type or inactive mutants with catalase. Dots indicate individual Pearson correlation coefficient data points. In the box-plots, the center lines indicate the medians, the box limits indicate the 25th and 75th percentiles as determined in the R software package, and the whiskers extend 1.5 times the interquartile range from the 25th and 75th percentiles. Means and the number of samples are shown on the box and X-axis, respectively. Statistical significance was calculated using a one-tailed Welch's t-test.
Figure 4(B) Peroxisomal translocation of other mitochondrial proteins such as MitoNEET/CISD1, Fis1, Miro1/2, and Tom70 (mitochondrial outer membrane proteins), and Hsp60 (mitochondrial matrix protein) was not observed in CCCP-treated cells. HeLa cells stably expressing HA-Parkin were treated with 15 µM CCCP for 3 hours, and then immuno-stained with anti-MitoNEET/CISD1, anti-Fis1, anti-Miro1/2, anti-Tom70, anti-Hsp60, and anti-catalase antibodies. Scale bars, 10 µm.(C) A multi-spanning outer membrane protein PBR (Peripheral Benzodiazepine Receptor) did not co-localize with catalase, but did with Tom20 during mitophagy. HeLa cells stably expressing HA-Parkin were treated with 15 µM CCCP for 3 hours, and then immuno-stained with anti-Flag, anti-Tom20, and anti-catalase antibodies. Scale bars, 10 µm.
Figure 5(A) siRNA-based knockdown of endogenous Tom70, Tom20, Tom40, and Sam50. HeLa cells treated with the corresponding siRNAs and immunoblotted with the indicated antibodies. AIF, Apoptosis-inducing factor.(B) HeLa cells were immuno-stained with anti-Flag and anti-catalase antibodies after treatment of each siRNA. Tom20- and Tom40-siRNA treatment inhibited import of Su9-GFP (the targeting sequence of the FoF1 ATPase subunit 9) into the mitochondria, leading to an accumulation of Su9-GFP precursor proteins in the cytosol and cell nucleus. 3Flag-MITOL still localized to mitochondria in Tom20, Tom40, and Sam50 siRNA-treated cells. In contrast, 3Flag-MITOL dispersed into the cytosol when Tom70 was knocked down. Scale bars, 10 µm.(C) Statistical analysis of the MITOL subcellular localization following 15 µM CCCP treatment for 3 hours in cells treated with control, Tom70, Tom20, Tom40, or Sam50 siRNAs. Su9-GFP was not imported into the mitochondria, but rather localized to the cytosol and nucleus following Tom20 and Tom40 knockdown. The number of HeLa cells with cytosol-localized Su9-GFP or 3Flag-MITOL in each siRNA experiment were determined. Data represent the mean ± s.e.m from > 100 cells in three biological replicates. (In case of Tom40, and Sam50 siRNAs, data represent the mean ± s.e.m from > 60 cells in three biological replicates.) Statistical significance was calculated using a one-tailed Welch's t-test.(D) HeLa cells treated with siControl or siTom70 were fractionated into cytosolic and mitochondrial fractions and then immunoblotted with anti-lactate dehydrogenase (LDH), anti-Tom20, and anti-Flag antibodies. LDH was used as a cytosolic marker. Although some MITOL detached from mitochondria during fractionation, sufficient amounts of MITOL were collected in the mitochondria-enriched fraction in control cells. In contrast, almost all of the MITOL was collected in the cytosolic fraction in siTom70-treated cells.
Figure 6(A) CRISPR/Cas9 gene editing was used to generate peroxisome-null cell lines by knocking out PEX19. In wild-type HCT116 cells, catalase localized to peroxisomes (dot-like structures), whereas in PEX19 -/- cells catalase was diffusely localized throughout the cytosol, indicating loss of peroxisomes. Scale bars, 10 µm.Wild-type and PEX19 -/- HCT116 cells stably expressing HA-Parkin and 3Flag-MITOL were treated with 10 µM valinomycin for 3 hours, and then subjected to immunocytochemistry with anti-Flag, anti-catalase, and anti-Hsp60 (B) antibodies. In wild-type HCT116 cells, MITOL translocated to peroxisomes, whereas MITOL remained associated with mitochondria in PEX19 -/- cells. Arrowheads indicate representative examples of 3Flag-MITOL co-localization with catalase rather than Hsp60 in wild-type HCT116 cells. Higher magnification images of the boxed regions are shown in the small panel. Scale bars, 10 µm.Wild-type and PEX19 -/- HCT116 cells stably expressing HA-Parkin and 3Flag-MITOL were treated with 10 µM valinomycin for 3 hours, and then subjected to immunocytochemistry with anti-Flag anti-Tom20 (C) antibodies. In wild-type HCT116 cells, MITOL translocated to peroxisomes, whereas MITOL remained associated with mitochondria in PEX19 -/- cells. Higher magnification images of the boxed regions are shown in the small panel. Scale bars, 10 µm.