EMBO/SourceData huggingface dataset:
Figure 5Drp1 knockdown cells were treated with DMSO (control) or with actinomycin D for 14 h to induce apoptosis and were decorated with antisera against Bax, cytochrome c, and Mic27 or Mic60 (see Appendix Figure S4). Three-color images were taken, whereby Mic27 or Mic60 were recorded in the STED mode. Relying on the Bax and the cytochrome c signals, we discriminated between healthy and apoptotic mitochondria before and after cytochrome c release. The distributions of Mic27 or Mic60 were analyzed by determining the normalized variance of the fluorescence intensity, which is a sensitive measure for the distribution of the labelled protein. The numbers within the columns represent the numbers of images analyzed and the error bars represent the standard error of the mean.
Figure 6Shown are seven optical sections through a mitochondrion of an apoptotic U2OS cell. Top and middle row: Tom22 and Bax (recorded in STED) channel, respectively. Bottom row: overlay (Tom22: red; Bax: green). Note the absence of Tom22 signal in the area enclosed by the Bax-ring. Displayed are raw data. Scale bar: 0.5 µm.
Figure 1Assay principle: RNAi was performed with luciferase-expressing cells that were challenged with or without CTLs and bi-specific antibody. Before readout, cell supernatant was removed and the remaining intact cells were lysed to measure the residual-cell-associated luciferase. To identify immune-checkpoint regulators, the difference between normalized luciferase measurements for conditions with CTLs and without CTLs was calculated. siRNAs enhancing CTL cytotoxicity would only reduce normalized luciferase levels under conditions with CTLs; hence, the difference between luciferase measurements will be > 0.Luc-CTL assay performed at different T cell to MCF7 cell ratio with PBMC-derived CD8+ T cells and anti-EpCAM x CD3 bi-specific antibody (○). Anti-CD19 × CD3 bi-specific Ab (▪) was used as a specificity control since CD19 is a B-lymphocyte-specific antigen and therefore this bsAb fails to cross-link tumor to T cells. Lower luciferase intensity indicates higher lysis. Error bars denote ± SEM.Luc-CTL assay was performed with MCF7 cells transfected with control or PD-L1-specific siRNAs and cocultured with or without CTLs and bsAb. For each condition, the luciferase activity of PD-L1-siRNA-treated cells was normalized to that of the control siRNA; n = 8. Error bars denote ± SEM.Comparison between the Luc-CTL assay (▪) and the classical chromium (Cr)-release assay (○) with MCF7 as target cells and survivin-specific T cells as effector cells at varying effector to target (E:T) ratios. Error bars denote ± SEM.
Figure 2B Correlation between replicates for screen 2 for both viability and toxicity sets, as determined by the Pearson rank correlation test.C-E Graphical summary of gene function related to modification of T cell-mediated tumor lysis and cellviability for screens 1, 2, and 3, respectively. Positive score = reduced cancer cellviability; negative score = increased viability. X-axis: influence on cellviability without addition of T cells. Y-axis: influence on cellviability with addition of T cells. Appropriate immune-suppressive (PD-L1, CEACAM-6, GAL-3) and lethality (UBC, PLK-1) controls, along with few positive (GRM4, GRK5) and negative (CCR9, IL8) candidate immune-modulatory hits are highlighted herein.C-E Graphical summary of gene function related to modification of T cell-mediated tumor lysis and cellviability for screens 1, 2, and 3, respectively. Positive score = reduced cancer cellviability; negative score = increased viability. X-axis: influence on cellviability without addition of T cells. Y-axis: influence on cellviability with addition of T cells. Appropriate immune-suppressive (PD-L1, CEACAM-6, GAL-3) and lethality (UBC, PLK-1) controls, along with few positive (GRM4, GRK5) and negative (CCR9, IL8) candidate immune-modulatory hits are highlighted herein.
Figure 4A MCF7 cells were transfected with the described siRNA sequences and harvested after 72 h for mRNA and protein estimation using RT-PCR (upper) and immunoblot (lower) analysis, respectively. GAPDH and beta-actin were used as controls for RNA and protein normalization, respectively.B Luc-CTL cytotoxicity assay with PBMC-derived CTLs and bi-specific Ab as effector population and MCF7 as target cells, which were transfected with individual (s1-s4) or pooled CCR9 siRNA sequences. PD-L1 and non-specific control siRNAs were used as positive and negative controls, respectively, for CTL-mediated cytotoxicity.C, D Cr-release assay showing % specific lysis of MCF7 cells by survivin-specific T cells at different ratios upon CCR9 knockdown (C) or overexpression (D). MCF7 cells were transfected with either CCR9 siRNA s1 (Δ), pooled siRNA sequences (○), positive control PD-L1 (□), and non-specific control siRNA (▪) (C) or with pCMV6-AC-His control vector (▪) and pCMV6-AC-His-CCR9 expression construct (○) (D) 72 h prior to the assay.E Cr-release assay showing % specific lysis of MDA-MB-231 breast tumor cell line by survivin-specific T cells at different ratios upon CCR9 knockdown (○) in comparison to the control knockdown (▪).F, G Cr-release assay showing lysis of patient-derived melanoma cells (M579-A2) by tumor-infiltrating lymphocytes (TIL 412) (F) or lysis of PANC-1 pancreatic adenocarcinoma cells by patient-derived pancreatic TIL 53 (G) at different E:T ratios upon CCR9 (○) or control (▪) knockdown.
Figure 5A, B ELISpot assay showing IFN-γ (A) and granzyme B (B) secretion by survivin-specific T cells, as spot numbers, upon CCR9 knockdown (black bars) in MCF7 cells compared to the control knockdown (white bars). T cells (TC) alone (grey bars) were used as control for background spot numbers.C Luminex assay showing cytokine levels in the supernatant from the coculture of survivin-specific TC and either CCR9hi MCF7 (transfected with CCR9-specific siRNA) or CCR9lo MCF7 (transfected with control siRNA) cells.D Phospho-plex analysis showing the phospho-STAT levels in survivin-specific TC upon encountering CCR9hi or CCR9lo MCF7 cells. Log2 ratio of mean fluorescent intensity (MFI) of the respective analytes to the unstimulated TC is plotted herein.E Immunoblot analysis showing the phospho-STAT1 levels in the CCR9hi-treated, CCR9lo-treated or unstimulated TC using the phospho-specific STAT1 (pTyr701) antibody. Beta-actin was used as the loading control.
Figure 6A ELISA showing CCL25 levels in cell lysates from indicated tumorcell lines. CCR9 knockdown (k.d.) in MCF7 cells was achieved using specific shRNA (see Materials and Methods).B Cr-release assay showing % specific lysis of MCF7 cells by survivin TC upon CCL25 (□) or CCR9 (○) inhibition using specific siRNAs in comparison to the control siRNA (▪). Mean ± SEM are depicted herein.C MCF7 cells were transfected with control or CCR9-specific siRNAs, and 48 h later, the supernatants (CCR9lo or CCR9hi SSN, respectively) were used to culture survivin TCs overnight. Supernatant-treated TCs were then used as effector cells against CCR9lo or CCR9hi MCF7 tumor cells in the Cr-release assay along with wild-type MCF7 cells. Mean ± SEM are depicted herein.D Cr-release assay showing % specific lysis of MCF7 cells that were pre-treated with or without pertussis toxin (PTX), or knocked down for CCR9 using specific siRNA. Mean ± SEM are depicted herein.E, F MCF7 cells transfected with control siRNA (CCR9hi) or CCR9 siRNA (CCR9lo) were cocultured with survivin TCs for 12 h. Gene microarray was performed with the total RNA extracted from purified T cells after the coculture. Volcano plot (E) illustrating fold change (FC; log2) in gene expression intensities compared with P-value (−log2) between CCR9hi- and CCR9lo-treated TCs. Horizontal bar at y = 4.32 represents a statistical significance of P = 0.05 (genes in gray below this line did not reach significance). LogFC cutoff at ± 0.5 is represented by the vertical lines. Heatmap representation of the top upregulated (LogFC > 0.5) and downregulated (LogFC < −0.85) genes (F) with P ≤ 0.05. Individual replicates per sample group are shown herein.
Figure 7A Cr-release assay showing TIL 209-mediated lysis of CCR9+ M579-A2 (transduced with control shRNA) or CCR9− M579-A2 cells (transduced with CCR9-specific shRNA). Curves represent mean ± SEM.C, D Tumorgrowth curves showing mean ± SEMtumor volume of CCR9+ or CCR9−M579-A2tumors in TIL-treated mice (C) or the PBS alone group (D). Statistical difference was calculated using the unpaired one-sided Mann-Whitney U-test.
Figure 1A) SH-SY5Y neuroblastoma cells were either cultivated in RPMI+10% FCS or starved in HBSS with or without addition of LY294002 or rapamycin. After 16 h PINK1 mRNA expression was determined by RT-qPCR and the PINK1 mRNA content of cells kept in RPMI+10% FCS was set as 1. Induction of autophagy by starvation or rapamycin resulted in an induction of PINK1 expression, comparable to the positive control LY294002; n = 4; * expression changes compared to the PINK1 expression in RPMI+10% FCS: LY294002: p<0.01; rapamycin: p<1×10−4; HBSS: p<0.005; HBSS+LY294002: p<5×10−6; HBSS+ rapamycin: p<0.0005; # expression changes compared to the PINK1 expression in RPMI+10% FCS+LY294002: p<0.05; + expression changes compared to the PINK1 expression in RPMI+10% FCS+rapamycin: p<0.0005.B) SH-SY5Y cells were either stably transduced with a control (nt) shRNA or a shRNA directed against PINK1 and cultivated in RPMI medium containing 5% or 10% FCS. Their PINK1 mRNA content was determined by RT-qPCR and PINK1 mRNA content of nt cells kept in medium with 10% FCS was set as 1. Serum reduction increased PINK1 mRNA in nt cells in accordance with the data shown in Fig. 1A, while stable PINK1 knockdown (kd) reduced PINK1 content under both conditions; n = 3; * expression changes compared to the PINK1 expression in RPMI+10% FCS: PINK1 kd 10% FCS p<0.0005; PINK1 induction by 5% FCS: p<0.05; # expression changes compared to the PINK1 expression in RPMI+5% FCS: PINK1 kd 5% FCS: p<0.005.C) SH-SY5Y cells without (nt) or with stable PINK1 knockdown (kd) were kept in medium with 5% FCS and either untreated or treated for 2 h with CCCP to stabilize PINK1. Afterwards the PINK1 63 kDa protein (arrowhead) and actin protein levels were determined by western blotting (see representative gel on the right). The quantification revealed a reduction of PINK1 protein under both conditions in PINK1 kd cells.
Figure 22A) SH-SY5Y cells were starved for 2 h in HBSS with Bafilomycin (+Baf) or left untreated in RPMI+5% FCS (- Baf). The LC3-II and actin content were determined by western blotting. A representative blot is shown on the right, showing only LC3-II bands in the Bafilomycin-treated samples. The LC3-II bands of Bafilomycin treated samples were normalized to actin and the relative LC3-II content of nt cells was set as 1. Cells with stable PINK1 knockdown exhibited a reduced LC3-II/actin ratio compared to the control (nt) cells; n = 4, p<0.005.2B) Cortical neurons from 3 different isolations (10-20 DIV) of WT and PINK1 KO mice were either non-starved or starved for 2 h in HBSS and the LC3-II and actin content was determined by western blotting. A representative blot is shown on the right. The relative LC3-II content of WT and PINK1 KO mice, respectively, was set as 1. Primary neurons showed a strong upregulation of autophagy in reaction to starvation but cells derived from PINK1 KO mice exhibited a reduced LC3-II/actin ratio compared to the WT cells; n = 5, p<0.001.2C) HeLa cells were transiently transfected with scrambled siRNA or PINK1 siRNA. After 48 h the LC3-II and actin content was determined by western blotting. A representative blot is shown on the right. The relative LC3-II content of cells transfected with scrambled siRNA was set as 1. Transient PINK1 knockdown resulted in a reduced LC3-II/actin ratio compared to the cells transfected with scrambled siRNA; n = 6; p<0.005.2D) HeLa cells were transiently transfected with PINK1-GFP, PINK1G309D-GFP or GFP. After 24 h cells were starved for 2 h in HBSS. Afterwards the LC3-II and actin content were determined by western blotting. A representative blot is shown on the right. The relative LC3-II content of cells transfected with GFP was set as 1. Transient PINK1 or PINK1G309D overexpression resulted in an increased LC3-II/actin ratio compared to cells transfected with GFP; n = 3, PINK1: p<0.01; PINK1G309D: p<0.05.
Figure 33A) Regular, non-transduced SH-SY5Y cells were cultivated either in RPMI+10% FCS or starved in HBSS medium for 24 and 40 h. The LAMP-2 and actin content were determined by western blotting and the relative LAMP-2 content of untreated cells was set as 1. Starvation enhanced LAMP-2protein levels; n = 3, p<0.05.3B) Transduced nt and PINK1 knockdown (kd) SH-SY5Y cells were cultivated either in RPMI+5% FCS or starved for 24 h and 40 h in HBSS. The LAMP-2 and actin content were determined by western blotting. A representative blot after 40 h starvation in HBSS is shown on the right. The relative LAMP-2 content of untreated cells was set as 1. Cells with stable PINK1 knockdown exhibited after 40 h a reduced LAMP-2/actin ratio compared to the nt cells; n = 4, p<0.05.3C) nt and PINK1 knockdown (kd) SH-SY5Y cells were starved for the indicated times with HBSS and afterwards stained for Lamp-2. Micrographs were taken with constant microscopical settings. LAMP-2 positive signals in each cell were quantified with ImageJ as described in Material and Methods. Knockdown of PINK1 resulted in a decreased amount of LAMP-2 positive stainings/cell after starvation; n = 2, at least 8 fields of view/condition, 89-124 cells/condition; 24 h: p<0.001; 40 h: p<0.05.3D) nt and PINK1 knockdown (kd) SH-SY5Y cells were stained with the photo-reactive dye MTR and either irradiated for 45 min or left untreated. 24 h and 48 h after irradiation the LAMP-2 and actin content were determined by western blotting. A representative blot 48 h after irradiation is shown on the right. The relative LAMP-2 content of untreated cells was set as 1. Cells with stable PINK1 knockdown exhibited after 48 h a reduced Lamp-2/actin ratio compared to the control (nt) cells; n = 5, p<0.001.3E) Acid phosphatase activity as parameter for lysosomal activity was quantified in nt and PINK1 knockdown (kd) SH-SY5Y cells cultivated in RPMI medium with 5% FCS. The phosphatase activity was measured and normalized to the protein content. The phosphatase activity of nt cells was set as 1. PINK1 knockdown mediated a reduction of lysosomal activity; n = 3; p<0.05.
Figure 44A) Oxygen consumption rate (OCR) was measured in nt and PINK1 knockdown (kd) SH-SY5Y cells without (nt) or with PINK1 knockdown (kd) cultivated in RPMI medium with 5% FCS. Although oxygen consumption appeared to be slightly impaired in cells with PINK1 kd, no significant changes were observed; n = 1 (quadruplicates).4B) Energy charge (EC) of nt and PINK1 knockdown (kd) SH-SY5Y cells grown in RPMI+5% FCS was determined as detailed in Material Methods. PINK1 knockdown resulted in a lower EC compared to nt cells; n = 5, p0.05.4C) nt and PINK1 knockdown (kd) SH-SY5Y cells were grown for 2 months in RPMI+5% FCS and their population doublings were determined. Starting from day 12 cells with PINK1 kd exhibited impaired cell population growth; n = 1 (triplicates); * p<0.05 (day 12) - p<1×10−6 (day 61).4D) SH-SY5Y cells were grown in RPMI+5% FCS and the amount of nt and PINK1 knockdown (kd) cells in S-phase was determined by BrdU incorporation. No differences in cell proliferation were visible between cells without (nt) and with PINK1 kd; n = 3.
Figure 55A) nt and PINK1 knockdown (kd) SH-SY5Y cells were either kept in RPMI medium with 5% FCS or starved with HBSS for 12 h. DEVD cleavage as parameter for caspase-3 activity was analyzed and normalized to the protein content. Cells with PINK1 knockdown demonstrated a significantly increased caspase-3 activity under both conditions; n = 4; RPMI+5% FCS: p<0.05; HBSS: p<0.01.5B) nt and PINK1 knockdown (kd) SH-SY5Y cells were either kept in RPMI medium with 5% FCS for 48 h or starved with HBSS for the indicated time points. In the representative western blot the appearance of the PARP 89 kDa cleaved product is depicted as well as GAPDH for normalizing.5C) nt and PINK1 knockdown (kd) SH-SY5Y cells were either kept in RPMI medium with 5% FCS for 48 h or starved with HBSS for the indicated time points. For quantification the cleaved PARP 89 kDa product was normalized to the full length 113 kDa PARP and the resulting value normalized to GAPDH. Cells with PINK1 knockdown demonstrated increased PARP cleavage that was significant after 24 h starvation; n = 4; 24 h: p<0.005.5D) HeLa cells were transfected with scrambled siRNA or PINK1 siRNA and GFP or GFP-Parkin or PINK1-GFP or PINK1G309D-GFP. After transfection cells were starved for additional 24 h with HBSS and afterwards the amount of adherent cells was determined. The number of adherent cells transfected with scrambled siRNA and the indicated plasmid was set as 1. Starvation-mediated increased cell loss after PINK1 knockdown could be rescued by PINK1 or PINK1G309D-GFP but not by GFP or Parkin; GFP: n = 5, p<0.005; Parkin: n = 3, p<0.05; PINK1: n = 5, ns; PINK1G309D-GFP: n = 3, ns.5E) HeLa cells and HeLa cells stably overexpressing LC3 were transfected with scrambled siRNA or PINK1 siRNA. After 48 h cells were starved in HBSS for additional 24 h and afterwards DEVD cleavage as parameter for caspase-3 activity was analyzed and normalized to 1,000,000 cells. PINK1 knockdown increased caspase-3 activity significantly, which was prevented by LC3 overexpression; n = 3; p<0.05.5F) HeLa cells and HeLa cells stably expressing LC3 were transfected with scrambled or PINK1 siRNA. 48 h post transfection cells were either left untreated (+ medium) or starved (+HBSS) for additional 24 h and afterwards the amount of adherent cells was determined. The amount of non-starved cells was set as 1. PINK1 knockdown resulted in elevated cell loss, which was prevented by LC3 overexpression; HeLa: n = 6, p<0.05; HeLa LC3: n = 5.
Figure 1.Cytoplasmic chromatin fragments in senescent cells. (A) Cytoplasmic chromatin fragments (CCFs) in senescent cells are strongly positive for histone H3. Yellow arrow marks CCF. (B) Increased proportion of cells with CCFs in RS or OIS. Mean ± SEM, n = 3; P < 0.01 (OIS), P < 0.002 (RS). Assays were performed 10 d after induction with tamoxifen (OIS) or 4 wk after the last passage and >90% SA β-gal+ (RS).(C) CCFs in OIS cells are lamin A/C negative. (D) Cells from C were scored for lamin A/C+ and lamin A/C− CCFs. Note that the majority of micronuclei in control cells are lamin A/C positive. Mean ± SEM, n = 3; P < 0.0006 for lamin A/C negative CCF con vs. OIS; P < 0.6 for lamin A/C positive CCF con vs. OIS.(E) CCFs in OIS are strongly positive for heterochromatic histone mark H3K27me3 but not for euchromatic mark H3K9ac. (F) Cells from E were scored for indicated histone modifications in CCFs. A single representative experiment is shown and at least 100 cells were scored per slide. Note the majority of micronuclei in control cells are positive for both marks.(G) CCFs in RS contain γ-H2AX but not 53BP1 (top). Intranuclear γ-H2AX foci colocalize with 53BP1 (bottom). (H) CCF+ and CCF− cells from G were scored for colocalizing intranuclear γ-H2AX and 53BP1 foci. Mean ± SEM, n = 3; P < 0.019. Bars (in IF panels), 10 µm.
Figure 2.Nuclear-to-cytoplasm chromatin blebbing in senescent cells associated with depletion of lamin B1. (A) Extrusion of GFP-H2B-positive chromatin fragment from nonmitotic RS nucleus. Confocal time-lapse microscopy of transiently transfected GFP-H2B-expressing cell, 60× original magnification, 150 nm optical section, time in mins. Bars: 10 µm; (insert) 2 µm.(B) Chromatin fragments blebbing out of nucleus are γ-H2AX positive. Bars: (top) 10 µm; (bottom) 5 µm.(C) Down-regulation of lamin B1 and lamin B receptor (LBR) in RS cells, assayed by Western blot. See Materials and methods for time-course details.(D) Depletion of lamin B1 from OIS cells, assayed by immunofluorescence. (E) A line-scan of lamin B1 fluorescence intensity along the arrows in D. Data shown are from a single representative experiment out of three repeats.. (F) Depletion of lamin B1 in BRAFV600E-induced OIS melanocytes in vitro. Bars, 10 µm. (G) Quantitative immunofluorescence of lamin B1 in melanocytes from F. A representative experiment out of two repeats is shown. At least 150 randomly selected cells were assessed.(H) Senescent nevusmelanocytes (n) stain less intensely for lamin B1 as compared with nonsenescent melanocytes in epidermis (e). White dotted line shows the basement membrane between the dermis and epidermis. Bottom panels (Epi and Nevus) are expanded from white boxed areas on top. Confocal microscopy for DAPI (blue), MelanA (red), and lamin B1 (green) stained tissue. Bars, 20 µm. (I) Quantitation of results from H for three different nevi. Epifluorescence images of lamin B1- and MelanA-stained nevi were obtained and epidermal or nevusMelanA-positive cells were scored for the presence (positive) of a characteristic lamin B1 "ring." At least 50 MelanA-expressing epidermalmelanocytes and at least 100 nevusmelanocytes were scored. Average of three different nevi ± SEM; P < 0.0005.
Figure 3.Blebbing of chromatin from nucleus to cytoplasm in senescent cells is associated with loss of nuclear envelope integrity. (A) Herniation of H3K27me3-positive chromatin into the cytoplasm of OIS cells. Yellow boxed area is magnified in bottom panels. Bars: (top panels) 10 µm; (bottom panels) 5 µm. (B) Quantitation of lamin B1 gaps or herniations in OIS. Mean ± SEM, n = 2; P < 0.01.(C) Isolated nuclei of senescent cells are permeable to both 70- and 500-kD dextrans, indicating impairment of the barrier function of nuclear envelope. Dark nuclei exclude fluorescent dextran. Bars, 10 µm. (D) Quantitation of results from C. Mean ± SD, n = 4; P < 0.000001 for both 70- and 500-kD dextrans.(E) Representative OIS SAHF+ nucleus showing dextran permeability. Bars, 10 µm. (F) Quantitation of dextran 70 uptake in SAHF+ and SAHF− OIS cells. P < 1.9 × 10−5. (G) In individual nuclei, chromatin extrusion and dextran intrusion occurred in close physical proximity. Right-hand panels are expanded from yellow boxed areas on the left. Bars: (left) 10 µm; (right) 2 µm.
Figure 4.Cytoplasmic histone is processed by a lysosomal/autophagy pathway. (A) Close juxtaposition of senescence-associated CCF (RS) with p62 nuclear bodies. Bars: 10 µm; (inset) 1 µm. (B) Quantitation of control and OIS cells with CCF overlapping p62 (p62+) or not (p62−). Mean ± SEM, n = 3.(C) Quantitation of proliferating and RS cells with CCF overlapping p62 (p62+) or not (p62−) and protein ubiquitination (FK2+) or not (FK2−). Mean ± SEM, n = 3; P < 0.0008 for FK2+/p62+ CCF, comparing proliferating and RS cells. (D) Ubiquitinated proteins appear to line chromatin surface in CCF. Yellow boxed areas are magnified in right-hand panels. Bars: (left panels) 10 µm; (right panels) 1 µm.(E) Apparent activation of cathepsin L in RS IMR90 cells. In contrast to RS cells, the majority of cathepsin L in proliferating control cells exists in its inactive pro-cathepsin L form. Loading was normalized by cell number and lamin A/C was used as a loading control. See Materials and methods for details of time course.(F) Accumulation of H3cs.1, a specific N-terminal cleavage product of H3, in OIS cells. See Materials and methods for details of time course. Western blotting was performed using the same cellular lysates as in Fig. S4 B, and the same lamin A/C panel is shown in both figures.(G) Accumulation of H3cs.1 and corresponding high mobility H3 in OIS.(H) Predominant cytoplasmic localization of H3cs.1 in senescent cells. α-Tubulin and lamin A/C were used as fractionation controls for cytoplasmic and nuclear fractions, respectively.