EMBO/SourceData huggingface dataset:
Figure 2Thioperamide treatment of tissue culture cells. BHK, CHO and HeLa cells were treated with thioperamide and processed as in Fig 1C. Low magnification views are shown after staining with anti-LBPA antibodies (green) and DAPI (blue). n=3 independent experiments with > 200 images acquired and analysed automatically.Cholesterol quantification by mass spectrometry. A431 cells were treated with DMSO alone, pitolisant 10µM (Pito), thioperamide 10µM (thio) or U18666A 10µM (U18) for 18h at 37°C. After extraction, free cholesterol, cholesteryl esters and total cholesterol were quantified by mass spectrometry, and normalized to the DMSO controls. (n=3 independent experiments, error bars = SD, one-way ANOVA, ****=p<0.0001Screen data plot of the cholesterol content of LBPA-endosomes. Automated unbiased quantification of the filipin integrated fluorescence signal (cholesterol content) in LBPA-containing endosomes, after treatment with each compound of the Prestwick library. As in Fig 1D, each dot is the average of replicates in the duplicate plates, and ≥600 cells were analysed per compound - only compounds that showed less than 20% toxicity are plotted. The fluorescence signal of LBPA-endosomes was used to segment the imaged and generate a mask, which was then applied on the micrographs to quantify the integrated intensity of filipin staining. The samples treated with thioperamide (pink), trimeprazine (light blue), DMSO (red) and U18666A (green) are indicated.
Figure 3Immunogold labelling with anti-LBPA antibodies. HeLa MZ cells were treated or not with thioperamide for 18h and processed for electron microscopy. Cryosections were labelled with antibodies against the late endosomal lipid LBPA followed by 5nm protein A-gold. Multivesicular endosomes are pseudocoloured (see Fig EV1 for uncoloured images). Bars, 200nm. The data in (A) were quantified in a double-blind analysis of two sets of 16 micrographs for each condition; the number of gold particles per endosome is shown in a scatter plot (B) for each endosome identified without any bias in each micrograph of the two control (DMSO) and thioperamide-treated (THIO) samples.Distribution of LBPA-containing endosomes in the perinuclear region. Automated unbiased quantification of LBPA fluorescence in the perinuclear region of the cells, after treatment with each compound of the Prestwick library as in Fig 2C. As in Fig 1D, each dot is the average of replicates in the duplicate plates, and ≥600 cells were analysed per compound - only compounds that showed less than 20% toxicity are plotted. The integrated intensity of the LBPA fluorescence signal was measured within a mask of the perinuclear region in each cell, calculated from the nuclei DAPI-staining. The samples treated with thioperamide (pink), trimeprazine (light blue), DMSO (red) and U18666A (green) are indicated. Number of perinuclear LBPA endosomes. The number of individual LBPA-positive structures was measured in the perinuclear region as in (C). The z-factors are shown to evaluate the distribution of endosomes containing LBPA; color code as in (C).
Figure 4Effect of Pitolisant on LBPA. HeLa MZ cells treated or not with pitolisant 10µM for 18h at 37°C were labeled with DAPI and anti-LBPA antibodies and analysed by fluorescence microscopy (quantification in fig EV3A).LBPA intensity in a mixed population of cells expressing HRH3-GFP. After transfection with HRH3-GFP, uncloned stably expressing cells (C) were labelled with anti-LBPA antibodies and analysed by automated microscopy (C). Unbiased quantification (D) shows the inverse correlation between HRH3-GFP expression (high expressing cells in green) and the endosome integrated intensity of LBPA staining (high LBPA labelling in red). (n=2 independent experiments with 500,000 cells analysed automatically, error bars = SD).LBPA intensity in cells expressing or not HRH3-GFP. HeLa MZ cells stably expressing HRH3-GFP grown in 96-well plates were separately treated, with 4 different siRNAs that target HRH3 (siHRH3#1; siHRH3#2; siHRH3#3; siHRH3#4) or with control non-target (siNT) siRNA (E). HRH3-GFP was analysed by fluorescence microscopy in 4 rows of cells per condition; micrographs are stitched together in the montage. Panel F shows an example of cells treated with siHRH3#2 or siNT, and then labelled with DAPI and antibodies against LBPA. Cells treated as in (E) and labelled with DAPI and antibodies against LBPA as in (F), were analysed by automated microscopy and the integrated intensities of LBPA (left panel) and HRH3-GFP (right panel) signals are compared (G). (n=2 independent experiments with 192 images acquired and analysed automatically, error bars = SD).
Figure 5Treatment of NPC fibroblasts and NPC null mice with thioperamide. Fibroblast lines obtained from patients with well-established heterozygote mutations in the NPC1 (GM17912 line: NPC1 P1007A / T1036M; GM17911 line: NPC1 I1061T / T1036M) or with a homozygote mutation in the NPC2 gene (GM17910 line: C93F / C93F) were treated or not for 72h with thioperamide 10µM, stained with filipin (cholesterol) and analysed by fluorescence automated microscopy.Quantification of cholesterol and LBPA staining in NPC fibroblasts. Cells as in (A) were treated or not with thioperamide for 48h or 72h, labelled with filipin (cholesterol) and anti-LBPA antibodies, and analysed by fluorescence automated microscopy. The panels show the integrated intensity of the filipin (left) and LBPA (right) signals were quantified after 48 (top) and 72h (bottom). The colour code of each fibroblast cell line is as in (A). (n=3 independent experiments with 144 images acquired and analysed automatically, >2000 cells per experiment, error bars = SD, one-way ANOVA, *=p<0.05; **=p<0.005;***=p<0.001).Quantification of cholesterol in NPC fibroblasts by mass spectrometry. NPC cell lines (A) were treated or not with thioperamide or 0.1% (2-Hydroxypropyl)-ß-cyclodextrin for 72h. After extraction, lipids were analysed and quantified by mass spectrometry. (n=3; error bars = SD, one-way ANOVA, *=p<0.05; **=p<0.005;***=p<0.001)Quantification of cell counts in the 3 NPC cell lines treated with thioperamide. The experiment was as in (A-C) except that nuclei were labelled with DAPI and quantified by automated microscopy. Data are normalized to DMSO control (n=2 independent experiments, 75 images per experiments)
Figure 6Effects of thioperamide on cholesterol-dependent transcriptional regulation. The parental HeLa MZ cells, NPC1 KO cells or NPC2 KO cells were treated or not with thioperamide 10 μM for 18h. Total mRNA was extracted and both LDLR mRNA and HMG CoA reductase mRNA were quantified by RT-PCR. (n=3 independent experiments, error bars = SD, one-way ANOVA, *=p<0.05; **=p<0.005)Quantification of cholesterol in NPC null mice by enzymatic analysis. WT or NPC1 null mice were treated or not with thioperamide for 6 weeks after weaning and sacrificed. The total content of unesterified cholesterol in the corresponding liver extracts was then quantified using an enzymatic assay and is expressed in nmol per mg tissue. The total content of LBPA in the same liver extracts was quantified by mass spectrometry (see Appendix Figure S1), and is therefore expressed as a percentage of total phospholipids. The total LBPA content of WT mice was only marginally increased by the drug, either because the doses were low, or because the contribution from tissue material unaffected by the drug obscured selective changes at the cellular level (despite much effort, we were unable to visualize LBPA in liver samples by immunocytochemistry). The relative ratio of LBPA vs. cholesterol values is shown.
Figure 1Silver staining of protein components in the Ago3 complex immunoisolated from BmN4 cells. P150 and P130 co-immunoprecipitated with Ago3. n.i.: non-immune IgG.Western blots showing the presence of Vret-L (P150) and Vret-S (P130) in the Ago3 complex in A. n.i.: non-immune IgG.Top: western blot showing Vret-L and Vret-S immunoprecipitated from BmN4 cells upon UV irradiation. Bottom: CLIP signals showing that Vret-L, but not Vret-S, binds RNAs in vivo.Five upper panels: Northern blots showing the levels of RT3-piRNA, Bmmar6-piRNA, R2Bm-piRNA, and R1Bm-piRNA in normal (Control), Vret-L/S-depleted (Vret KD), Vret-L-depleted (Vret-L KD), and Vret-S-depleted (Vret-S KD) cells. Bantam (miRNA) was detected as a loading control. Two lower panels: western blots showing the efficiency of the Vret knockdown. β-Tub was detected as a loading control.Two upper panels: western blots showing the abundances of Flag-Vret-L and Ago3 in both samples. Note that Flag-Vret-L is present only in the Vret-L complex but not with Ago3 isolated from total cell lysates (Fig EV1F). Bottom panel: Northern blot showing the level of PiggyBac-piRNA associated with Ago3 in total lysate (Ago3-IP) and in the Vret-L complex (Flag-Vret-IP). The ratio of the piRNA signal intensity in the two samples is indicated at the bottom.Two upper panels: western blots showing the abundances of Flag-Vret-L and Siwi in both samples. Bottom panel: Northern blot showing the level of RT3-piRNA associated with Siwi in the total lysate (Siwi-IP) and in the Vret-L complex (Flag-Vret-IP).Boxplot showing log2 fold-change of Vret-KD (RPM)/Control (RPM) values of piRNAs in increased, unchanged and decreased groups defined by Ago3-KD (RPM)/Control (RPM) values shown in Fig EV1I. Boxplot represents median, first and third quartile, and maximum and minimum values of the log2 fold-change of piRNAs (N = 2). Outliers are represented as open circles.Flag-EGFP and -Vret-L WT and mutants were immunoprecipitated using the anti-Flag antibody and then western blotting was performed using anti-Flag, anti-Siwi, anti-Ago3 and anti-Vret antibodies. The domain structures of Tud1mut (Y753A/Y757A/N759A) and Tud2mut (Y973A/ Y976A/N978A) are shown.
Figure 2Immunofluorescence shows that the Vret signals (green) co-localize with the Ago3 signals (red). DAPI shows the nuclei (blue). Scale bar: 10 μm. The three panels on the right-hand side show high magnification images of the part indicated by the white dashed line box in the image on the left-hand side. This panel arrangement applies also for panels B−H. The bar chart shows the percentage of Vret-positive nuage in Ago3-positive nuage. Immunofluorescence shows that the Vret signals (green) partially co-localize with the Siwi signals (red). DAPI shows the nuclei (blue). Scale bar: 10 μm. The bar chart shows the percentage of Vret-positive nuage in Siwi-positive nuage.Immunofluorescence showing the Ago3 signals (green) in control and Vret-depleted BmN4 cells (Vret KD). Vret is shown in red. DAPI shows the nuclei (blue). Scale bar: 10 μm. Immunofluorescence showing the Siwi signals (green) in control and Vret-depleted BmN4 cells (Vret KD). Vret is shown in red. DAPI shows the nuclei (blue). Scale bar: 10 μm.Immunofluorescence showing the Vret signals (red) in control and Ago3-depleted BmN4 cells (Ago3 KD). Ago3 is shown in green. DAPI shows the nuclei (blue). Scale bar: 10 μm. Immunofluorescence showing the Siwi signals (red) in control and Ago3-depleted BmN4 cells (Ago3 KD). Ago3 is shown in green. DAPI shows the nuclei (blue). Scale bar: 10 μm.Immunofluorescence showing Flag-Ago3 WT, KA mutant and DDH mutant signals (green) expressed in naïve BmN4 cells (Control). DAPI shows the nuclei (blue). Scale bar: 10 μm. Immunofluorescence showing Flag-Ago3 WT, KA mutant and DDH mutant signals (green) in Ago3-depleted cells (Ago3 KD). DAPI shows the nuclei (blue). Scale bar: 10 μm.
Figure 3Immunofluorescence showing the Ago3 signals (green) in control and Siwi-depleted BmN4 cells (Siwi KD). Siwi is shown in red. DAPI shows the nuclei (blue). Scale bar: 10 μm. The three panels on the right-hand side show high magnification images of the part indicated by the white dashed line box in the images on the left-hand side. This panel arrangement applies also for panels B, H and I. Bar chart indicates dot sizes of > 100 Ago3 particles in each case (Large: IntDen value > 106; Small: IntDen value < 106). Immunofluorescence showing the Vret signals (green) in control and Siwi-depleted BmN4 cells (Siwi KD). Siwi is shown in red. DAPI shows the nuclei (blue). Scale bar: 10 μm. Bar chart indicates dot sizes of > 100 Ago3 particles in each case (Large: IntDen value > 105; Small: IntDen value < 105).Western blotting was performed before and after Siwi KD using the anti-Ago3 antibody. Total BmN4 lysate (Total), supernatant (Sup) and pellet (Pellet) fractions upon centrifugation were used.Western blotting was performed using the anti-Ago3 antibody on Ago3 immunoisolated from Siwi-depleted cells. Ago3 immunoprecipitated was untreated (−) or treated with phosphatase (+) prior to western botting.Western blot showing the degree of phosphorylation of Flag-Ago3 WT and the 8SA mutant in Siwi-depleted cells (Siwi KD).Western blots showing the degree of phosphorylation of Flag-Ago3 WT and its DDH and KA mutants in Siwi-depleted cells (Siwi KD). The second panel from the top corresponds to the top panel with a longer exposure time. Siwi and β-Tub as a loading control were also detected also by western blotting.Western blotting was performed using anti-Ago3, anti-Vret and anti-Siwi antibodies on lysates of BmN4 cells before (Control) and after Siwi (Siwi KD) and Siwi/Vret (Siwi/Vret KD) depletion. β-Tub was detected as a loading control.Immunofluorescence showing the Flag-Ago3 signals (red) in normal (Control) and Siwi-depleted BmN4 cells (Siwi KD). DAPI shows the nuclei (blue). Scale bar: 10 μm.Immunofluorescence showing the Flag-Ago3 8SA and 8SE mutant signals (red) in normal (Control) and Siwi-depleted BmN4 cells (Siwi KD). DAPI shows the nuclei (blue). Scale bar: 10 μm.
Figure 4Western blot showing Ago3 immunopurified from BmN4 cells before (Control) and after Siwi knockdown (Siwi KD). 32P-labeling of RNAs isolated from Ago3 (a mixture of unphosphorylated and phosphorylated) immunopurified from Siwi-depleted cells. 15-20-nt RNAs (indicated by a black line) were isolated and sequenced.The measurement of distances between the 3′-ends of Target-S (15-20-nt RNAs in A) and the 5′-ends of Ago3-bound piRNAs.32P-labeling of RNAs isolated from Ago3. Target-Ss are isolated from Siwi-depleted BmN4 cells but are not isolated from Siwi/Vret double knockdown cells.Western blot showing Ago3 immunopurified from BmN4 cells before (Control) and after Siwi knockdown (Siwi KD). Northern blot showing Bmmar6-piRNA precursors in the Ago3 complex. 50-100-nt RNAs (indicated by a black line) were isolated and sequenced.The measurement of distances between the 5′-ends of Target-L and the 5′-ends of Ago3-bound piRNAs.The measurement of distances between the 5′- and 3′-ends of Target-L fragments on the same genomic strand. Heat map displays 5′-ends of Target-L in a window around the most abundant 1,000 3′-ends of Target-L. The measurement of distances between the 5′-ends and 3′-ends of Target-S fragments on the same genomic strand. The heat map displays 5′-ends of Target-S in a window around the most abundant 1,000 3′-ends of Target-S. The measurement of distances between the 5′-ends of Target-L and the 3′-ends of Target-S on the same genomic strand. The heat map displays 5′-ends of Target-L in a window around the most abundant 1,000 3′-ends of Target-S. The measurement of distances between the 5′-ends of Target-S and the 3′-ends of Target-L on the same genomic strand. The heat map displays 5′-ends of Target-S in a window around the most abundant 1,000 3′-ends of Target-L.
Figure 5Immunofluorescence showing the Ago3 signals (green) in Siwi-depleted BmN4 cells (Siwi KD) and Siwi KD cells where Flag-Siwi (red) was expressed. DAPI shows the nuclei (blue). Scale bar: 10 μm. The panels on the right-hand side show high magnification images of the part indicated by the white dashed line box in the images on the left-hand side. This arrangement applies also for panel C. Bar chart indicates dot sizes of > 100 Ago3 particles in each case (Large: IntDen value > 105; Small: IntDen value < 105). A significant difference was found plus/minus Flag-Siwi expression by the Fisher's exact test (P < 0.05).Western blots show that the degree of Ago3 phosphorylation was reduced upon Siwi KA mutant as well as Siwi WT and DDH mutant expression.Immunofluorescence showing the Ago3 signals (green) in Siwi-depleted BmN4 cells (Siwi KD) and Siwi KD cells where Flag-Siwi KA mutant (red) was expressed. DAPI shows the nuclei (blue). Scale bar: 10 μm. Bar chart indicates dot sizes of > 100 Ago3 particles in each case (Large: IntDen value > 105; Small: IntDen value < 105). A significant difference was found plus/minus Flag-Siwi expression by the Fisher's exact test (P < 0.05).
Figure 1(C, D) Representative confocal images of expanded centrioles from RPE-1 cells stained for α/β-tubulin (αβTub, magenta) and SFI1 (green). Right panels show top view images across the centriolar length confirming the distal localization of SFI1 at centrioles. The white arrowhead indicates SFI1 distal dot at centrioles. Scale bars: 200 nm and 100 nm (right panels). Average position of SFI1 alongside the centriole is shown in (D).(E, F) Representative confocal images of expanded centrioles from RPE-1 cells stained for α/β-tubulin (αβTub, magenta) and Centrin 2/3 (Cetn2/3, grey). Right panels show top view images across the centriolar length confirming the distal localization of Centrin2/3 at centrioles. The white arrowhead indicates Centrin2/3 distal dot at centrioles. Scale bars: 200 nm and 100 nm (right panels). Average position of Centrin2/3 alongside the centriole is shown in (F).(G, H) Representative confocal images of expanded centrioles from RPE-1 cells stained for α/β-tubulin (αβTub, magenta) and Centrin 3 (Cetn3, cyan). Right panels show top view images across the centriolar length confirming the distal localization of Centrin 3 at centrioles. The white arrowhead indicates Centrin 3 distal dot at centrioles. Scale bars: 200 nm and 100 nm (right panels). Average position of Centrin 3 alongside the centriole is shown in (H).(I, J) Representative confocal images of expanded centrioles from RPE-1 cells stained for α/β-tubulin (αβTub, magenta), SFI1 (green) and Centrin 2/3 (Cetn3, grey). Right panels show top view images confirming the distal localization of SFI1 and Centrin 2/3 at centrioles. Scale bars: 200 nm and 100 nm (right panels). Average position of SFI1 and Centrin2/3 alongside the centriole is shown in (J).
Figure 3(A-F) Representative confocal images of expanded U2OS centrioles treated with siCT (A, D), siSFI1 (B, E) and siPOC5 (C, F) stained for α/β-tubulin (αβTub, magenta) and SFI1 (A-C, green) or Centrin2/3 (D-F, grey). Insets show top views of expanded centrioles at different positions along the centriole (P= proximal, C= central and D= distal). Note that in the absence of SFI1 and Centrin staining at the distal tip, orientation of the centriole was decided based on the larger diameter of the proximal region compared to the distal one, as previously observed in cryo-tomography (Greenan et al, 2020). White arrowheads points to the distal dot of SFI1 and Centrin that disappear in SFI1-depleted (yellow arrowheads) but not in POC5-depleted centrioles. Scale bars: 200 nm and 100 nm (inset). Longitudinal and radial localization of SFI1 and Centrin2/3 in siCT (A, D), siSFI1 (B, E) and siPOC5 (C, F) are presented below the corresponding image. N=25, 40 and 60 centrioles from 3 independent experiments. N=29, 34, 34 centrioles from 3 independent experiments.(K-N) Representative images of expanded U2OS cells expressing GFP alone or GFP+SFI1-RR and treated with siCT or siSFI1. Cells were stained for α/β-tubulin (αβTub, magenta) and SFI1 (K, green) or Centrin2/3 (M, grey). Yellow asterisk indicates the centriole lacking SFI1 and Centrin distal dots. Scale bar: 250 nm. Expression of GFP+SFI1-RR in siSFI1 treated cell rescues the presence of SFI1 and Centrin at the distal tip of the centriole.(O, P) Representative confocal images of expanded Cetn2 WT, Cetn KO or Cetn2 rescue RPE-1. Cells were stained for α/β-tubulin (αβTub, magenta) and Centrin2 (O, grey) or SFI1 (P, green). Arrowheads indicate the presence (white) or the absence (yellow) of Centrin2 and SFI1. Scale bar: 200nm. Quantification shows the total absence of Centrin2 in the KO cells correlating with the absence of SFI1. Both Centrin2 and SFI1 localization are rescued when Centrin2 is re-expressed in KO cells.
Figure 4(A) Representative confocal images of expanded duplicating centrioles from siCT- and siSFI1- treated U2OS cells. Cells were stained for SFI1 (green) and α/β-tubulin (αβTub, magenta). Inset shows a distal position of the mother centriole where SFI1 signal is visible. White arrowhead indicates the position of SFI1 distal dot in the procentriole of control cell, which is lost in SFI1-depleted cells (yellow arrowhead). Scale bars: 200 nm. (B) Quantification of the percentage of SFI1-negative procentrioles. (C) Quantification of the percentage of duplicating centrioles.(D) Representative confocal image of expanded duplicating centrioles from siCT and siSFI1 U2OS treated cells. Cells were stained for HsSAS-6 (yellow) and α/β-tubulin (αβTub, magenta). Quantification shows no difference in the percentage of HsSAS-6-positive centrioles in siSFI1-depleted cells compared to control cells. (E) Representative confocal image of expanded duplicating centrioles from siCT and siSFI1 U2OS treated cells. Cells were stained for STIL (yellow) and α/β-tubulin (αβTub, magenta). Quantification shows no difference in the percentage of STIL-positive centrioles in siSFI1 compared to control cells.(F) Top views of expanded U2OS centrioles treated with siCT or siSFI1 stained for α/β-tubulin (αβTub, magenta). Scale bars: 200 nm. (G) Roundness index of centrioles from siCT and siSFI1-treated cells. (H) Length (circle) and diameter (square) of expanded centrioles in siCT or siSFI1-treated cells.(I) Representative confocal images of expanded U2OS centrioles from siCT and siSFI1-treated cells stained for α/β-tubulin (αβTub, magenta). White stars point to broken microtubule wall. Scale bars: 200 nm. (J) Percentage of abnormal centrioles in the indicated conditions.(K) Top views of expanded procentrioles from U2OS cells treated with siCT or siSFI1 and stained for α/β-tubulin (αβTub, magenta). (L) Roundness index of procentrioles from siCT and siSFI1-treated cells.(M) Representative confocal images of expanded U2OS centrioles from siCT- and siSFI1-treated cells stained for α/β-tubulin (αβTub, magenta) and Centrin (Cetn2/3, grey). White dashed lines delimitate the proximal, central and distal regions. White star points to the broken microtubule wall. (N) Centrin coverage (% of the total tubulin length) along the centriole in the indicated conditions.(O) Representative images of expanded U2OS expressing GFP alone or GFP+SFI1-RR and treated with siCT or siSFI1. Cells were stained for α/β-tubulin (αβTub, magenta) and SFI1 (green) or Centrin2/3 (grey). Red arrowhead indicates abnormal centriole. (P) Percentage of abnormal centrioles in the indicated conditions.