Journal: Redox Biology

Article Title: Excessive ER-mitochondria coupling: A DRP1-driven mechanism underlying mitochondrial dysfunction and impaired autophagy in stress-induced depression-like behavior in mice

doi: 10.1016/j.redox.2026.104121

Figure Lengend Snippet: Chronic social defeat stress induces MERC alterations and impairs autophagy in hippocampal neurons. A) Experimental timeline of chronic social defeat stress (CSDS), behavioral testing, and proteomic analysis. B) Representative trajectory heatmaps from the social interaction test (SIT) for control and CSDS-exposed mice. C) Behavioral tests including SIT (P < 0.0001; Interaction, F (1, 44) = 7.281, P = 0.0098), sucrose preference test (SPT, P < 0.0001) and forced swimming test (FST, P < 0.0001) were performed in mice. Student's t -test or Two-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n = 12 mice per group). ∗∗ p < 0.01, ∗∗∗ p < 0.001. D) Heatmap of hippocampal proteins detected by proteomic analysis (n = 3 samples per group; each sample pooled from 6 hippocampi). E) Subcellular localization analysis of differentially expressed proteins. F) KEGG pathway enrichment analysis of differentially expressed genes between control and CSDS groups (Fisher's exact test, adjusted P < 0.05). G) Mitochondrial respiratory function assessed by basal respiration, ATP production, and maximal respiratory capacity. Student t-test (P < 0.0001; P = 0.0046; P = 0.0118). The data were expressed as mean ± SEM (n = 6 mice in each group). ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001. H) Representative TEM images of CA1 neurons (left) and quantitative analysis of mitochondria-ER distance, mitochondrial perimeter, mitochondrial area and ERMICC ratio (the ratio of MERC length to product of mitochondrial perimeter and MERC distance) (right). Scale: 500 nm; Student t-test (P < 0.0001; P = 0.0396; P = 0.0003; P = 0.0374). The data were expressed as mean ± SEM (n = 5 mice per group, for each mouse, all mitochondria within neuronal regions from five non overlapping hippocampal fields were analyzed, and the average value was taken as one point). ∗ p < 0.05, ∗∗∗ p < 0.001. I) The representative images of PLA targeting IP3R3-GRP75 or GRP75-VDAC1 interaction in hippocampal CA1 (left) and the quantification of PLA red fluorescent spots (top line, Interaction, F (1, 16) = 0.9143, P = 0.3532) were performed using image J (right). Scale: 50 μm; nucleus (DAPI, blue). Two-way analysis of variance using sidak multiple comparison test. The data were expressed as mean ± SEM (n = 5 mice brain slices). ∗∗ p < 0.01. J) Representative TEM images (left) and quantification of autophagosomes in CA1 neurons (right). Autophagosome is shown in red. Student t-test (P = 0.0005). The data were expressed as mean ± SEM (n = 6 mice in each group, for each mouse, all mitochondria within neuronal regions from five non overlapping hippocampal fields were analyzed, and the average value was taken as one point). ∗∗∗ p < 0.001. K) Western blot analysis (left) and quantification (right) of p62, LC3Ⅱ/LC3Ⅰ, LAMP1, PINK1 and Parkin in hippocampal tissues. Student t-test (P = 0.0010; P = 0.0067; P = 0.0073; P = 0.0043; P = 0.0002). The data were expressed as mean ± SEM (n = 6 mice in each group). ∗∗ p < 0.01, ∗∗∗ p < 0.001.

Article Snippet: Multiplex staining was performed using TSA-based immunofluorescence with primary antibodies: Drp1 (CST 12741S, 1:100), MAP2 (ab32454, 1:1000), GFAP (CST 12389, 1:400), IBA1 (ab178846, 1:1000), Vglut1 (CST #27181, 1:800), Vglut2 (ab216463, 1:250), OLIG2 (CST #65915, 1:400), and LAMP1 (CST 99437S, 1:100).

Techniques: Control, Comparison, Western Blot

Journal: Redox Biology

Article Title: Excessive ER-mitochondria coupling: A DRP1-driven mechanism underlying mitochondrial dysfunction and impaired autophagy in stress-induced depression-like behavior in mice

doi: 10.1016/j.redox.2026.104121

Figure Lengend Snippet: Drp1 knockdown rescues CSDS-induced MERC remodeling and autophagy impairment. A) Mitochondrial respiration parameters including basal respiration (Interaction, F (1, 20) = 9.360, P = 0.0062), ATP production (Interaction, F (1, 20) = 15.14, P = 0.0009) and maximum respiratory capacity (Interaction, F (1, 20) = 0.9504, P = 0.3413). Two-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n = 6 mice in each group). ns, p > 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001. B) Representative TEM images (left) and mitochondria-ER distance (Interaction, F (1, 16) = 7.265, P = 0.0159), mitochondrial perimeter (Interaction, F (1, 16) = 26.96, P < 0.0001), mitochondrial area (Interaction, F (1, 16) = 29.34, P < 0.0001) and ERMICC ratio quantification (right, Interaction, F (1, 16) = 19.24, P = 0.0005) in CA1 neurons. Scale: 200 nm; Two-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n = 5 mice in each group, for each mouse, all mitochondria within neuronal regions from five non overlapping hippocampal fields were analyzed, and the average value was taken as one point). ns, p > 0.05, ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001 C) The representative images of PLA targeting IP3R3-GRP75 or GRP75-VDAC1 interaction in hippocampal CA1 (left) and the quantification of PLA red fluorescent spots (top, Interaction, F (1, 16) = 0.1194, P = 0.7342) and the percentage of PLA spots in Vglut2 (bottom, Interaction, F (1, 16) = 5.801, P = 0.0284) were performed using image J (right). Scale: 20 μm; Vglut2 (Neuron, green), nucleus (DAPI, blue). Two-way ANOVA with Tukey's multiple comparisons test. The data were expressed as mean ± SEM (n = 5 mouse brain slices). ∗∗∗ p < 0.001. D) TEM quantification of autophagosomes in CA1 (red). Two-way ANOVA with Tukey's multiple comparisons test (Interaction, F (1, 16) = 9.800, P = 0.0065). The data were expressed as mean ± SEM (n = 5 mice in each group, for each mouse, all mitochondria within neuronal regions from five non overlapping hippocampal fields were analyzed, and the average value was taken as one point). ∗ p < 0.05. E) Representative images of LAMP1 (red), rAVV (green) and DAPI (blue) fluorescence in CA1 region (left). The percentage of co-localized fluorescence was quantified (right, n = 8 mice brain slices). Scale bar: 50 or 2 μm. Two-way ANOVA with Tukey's multiple comparisons test (Interaction, F (1, 28) = 25.14, P < 0.0001). The data were expressed as mean ± SEM. ns, p > 0.05, ∗ p < 0.05, ∗∗∗ p < 0.001.

Article Snippet: Multiplex staining was performed using TSA-based immunofluorescence with primary antibodies: Drp1 (CST 12741S, 1:100), MAP2 (ab32454, 1:1000), GFAP (CST 12389, 1:400), IBA1 (ab178846, 1:1000), Vglut1 (CST #27181, 1:800), Vglut2 (ab216463, 1:250), OLIG2 (CST #65915, 1:400), and LAMP1 (CST 99437S, 1:100).

Techniques: Knockdown, Fluorescence

Journal: Redox Biology

Article Title: Excessive ER-mitochondria coupling: A DRP1-driven mechanism underlying mitochondrial dysfunction and impaired autophagy in stress-induced depression-like behavior in mice

doi: 10.1016/j.redox.2026.104121

Figure Lengend Snippet: Disruption of ER-mitochondria contacts improves neuronal function and enhances autophagy in CSDS. A) Strategy for generating Vglut2 neuron-specific GRP75 ( Hspa9 ) knockout mice using Cre-loxP system. B) Representative SIT trajectory heatmaps. C) Behavioral tests including SIT (Interaction, F (1, 44) = 11.16, P = 0.0017; Interaction, F (3, 94) = 3.122, P = 0.0296), SPT (Interaction, F (1, 44) = 4.675, P = 0.0361) and FST (Interaction, F (1, 44) = 5.453, P = 0.0242) were performed in mice. Two-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n = 12 mice in each group). ns, p > 0.05, ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001. D) The representative TEM images of CA1 neuron (left) and quantitative analysis showed that the distance between mitochondria and ER (right, Interaction, F (1, 16) = 18.58, P = 0.0005), mitochondrial perimeter (Interaction, F (1, 16) = 17.89, P = 0.0006), mitochondrial area (Interaction, F (1, 16) = 20.58, P = 0.0003) and ERMICC ratio quantification (Interaction, F (1, 16) = 1.205, P = 0.2886). Scale: 200 nm; Two-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n = 5 mice per group, for each mouse, all mitochondria within neuronal regions from five non overlapping hippocampal fields were analyzed, and the average value was taken as one point). ns, p > 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001. E) The representative traces, amplitude (Interaction, F (1, 28) = 1.152, P = 0.2922) and frequency (Interaction, F (1, 28) = 6.497, P = 0.0166) statistical maps recorded by sEPSC and the frequency accumulation map of sEPSC in CA1 neurons. Two-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n ≥ 6 mice in each group). ns, p > 0.05, ∗ p < 0.05, ∗∗ p < 0.01. F) Mitochondrial respiratory function, including basal respiration (Interaction, F (1, 20) = 4.588, P = 0.0447), ATP production (Interaction, F (1, 20) = 4.684, P = 0.0427) and maximum respiratory capacity (Interaction, F (1, 20) = 2.269, P = 0.1476). Two-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n = 6 mice in each group, three mice with six hippocampus). ns, p > 0.05, ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001. G) Typical transmission electron microscopy showed quantitative analysis of hippocampal CA1 autophagy (Interaction, F (1, 16) = 13.64, P = 0.0020). Autophagosome is shown in red. Two-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n = 5 mice in each group, for each mouse, all mitochondria within neuronal regions from five non overlapping hippocampal fields were analyzed, and the average value was taken as one point). ns, p > 0.05, ∗∗ p < 0.01. H) Representative images of LAMP1 (red), Vglut2 (green) and DAPI (blue) fluorescence in hippocampal CA1 region (lef). The percentage of co-localized fluorescence was quantified (right, n = 7 mice brain slices). Scale bar: 50 μm. Two-way analysis of variance using sidak multiple comparison test (Interaction, F (1, 24) = 26.58, P < 0.0001). The data were expressed as mean ± SEM. ns, p > 0.05, ∗∗∗ p < 0.001.

Article Snippet: Multiplex staining was performed using TSA-based immunofluorescence with primary antibodies: Drp1 (CST 12741S, 1:100), MAP2 (ab32454, 1:1000), GFAP (CST 12389, 1:400), IBA1 (ab178846, 1:1000), Vglut1 (CST #27181, 1:800), Vglut2 (ab216463, 1:250), OLIG2 (CST #65915, 1:400), and LAMP1 (CST 99437S, 1:100).

Techniques: Disruption, Knock-Out, Transmission Assay, Electron Microscopy, Fluorescence, Comparison

Journal: Redox Biology

Article Title: Excessive ER-mitochondria coupling: A DRP1-driven mechanism underlying mitochondrial dysfunction and impaired autophagy in stress-induced depression-like behavior in mice

doi: 10.1016/j.redox.2026.104121

Figure Lengend Snippet: Enhanced mitophagy rescues neuronal and mitochondrial deficits. A) Experimental timeline of viral injection, Idebenone administration, stress exposure, and behavioral testing. B) Representative SIT trajectory heatmaps. C) Behavioral assessments following idebenone treatment including SIT (Treatment, F (7, 88) = 17.63, P < 0.0001; Interaction, F (7, 176) = 7.266, P < 0.0001), SPT (Treatment, F (7, 88) = 10.38, P < 0.0001) and FST (Treatment, F (7, 88) = 17.05, P < 0.0001) were performed in mice. One-way ANOVA or Two-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n = 12 mice in each group). ns, p > 0.05, ∗ p < 0.05, ∗∗ p < 0.01. D) TEM quantification of autophagosomes in CA1 (Treatment, F (3, 16) = 16.33, P < 0.0001). Autophagosome is shown in red. Scale: 1 μm; One-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n = 5 mice in each group, for each mouse, all mitochondria within neuronal regions from five non overlapping hippocampal fields were analyzed, and the average value was taken as one point). ∗∗ p < 0.01, ∗∗∗ p < 0.001. E) Representative images of LAMP1 (red), rAVV (green) and DAPI (blue) fluorescence in hippocampal CA1 region or reconstructed images (left). The percentage of co-localized fluorescence was quantified (right, n = 8 mice brain slices). Scale bar: 50 or 2 μm. One-way ANOVA with Tukey's multiple comparisons test. (Treatment, F (3, 28) = 6.937, P = 0.0012). The data were expressed as mean ± SEM. ∗ p < 0.05, ∗∗ p < 0.01. F) The representative traces, amplitude (Treatment, F (3, 20) = 1.664, P = 0.2067) and frequency (Treatment, F (3, 16) = 9.310, P = 0.0008) statistical maps recorded by sEPSC and the frequency accumulation map of sEPSC in CA1 neurons. One-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n ≥ 5 mice in each group). ns, p > 0.05, ∗ p < 0.05, ∗∗ p < 0.01. G) Detection of mitochondrial energy metabolism, including basal respiration (Treatment, F (3, 20) = 37.82, P < 0.0001), ATP production (Treatment, F (3, 20) = 8.518, P = 0.0008) and maximum respiratory capacity (Treatment, F (3, 20) = 17.18, P < 0.0001). One-way ANOVA with Tukey's multiple comparisons test. Data are expressed as mean ± SEM (n = 6 mice in each group, three mice with six hippocampus). ∗∗ p < 0.01, ∗∗∗ p < 0.001.

Article Snippet: Multiplex staining was performed using TSA-based immunofluorescence with primary antibodies: Drp1 (CST 12741S, 1:100), MAP2 (ab32454, 1:1000), GFAP (CST 12389, 1:400), IBA1 (ab178846, 1:1000), Vglut1 (CST #27181, 1:800), Vglut2 (ab216463, 1:250), OLIG2 (CST #65915, 1:400), and LAMP1 (CST 99437S, 1:100).

Techniques: Injection, Fluorescence

Journal: bioRxiv

Article Title: Molecular basis of Salla Disease: R39C Mutation Effects on the Lysosomal Transporter Sialin

doi: 10.64898/2026.04.20.719580

Figure Lengend Snippet: Representative images of the effects of mutations on the lysosomal localisation of sialin visualised by epifluorescence microscopy. Wild-type (WT) or different mutated human sialin (R39C, R39K, E194A, E262A, E264A and I266A) tagged with EGFP (green) constructs were transiently expressed in HeLa cells by electroporation. After two days, cells were fixed and analysed under fluorescence microscopy using LAMP1 immunostaining (red) to detect late endosomes and lysosomes. The scale bar represents 10 µm.

Article Snippet: Coverslips were then incubated for at least 1 h with mouse anti-LAMP1 antibodies (H4A3; Developmental Studies Hybridoma Bank) at 0.75 μg/mL in blocking buffer, washed, and incubated with Cy3-conjugated donkey antimouse antibodies (Jackson ImmunoResearch) at 1.4 μg/mL or Alexa Fluor 555 goat antimouse antibodies (Invitrogen) at 2μg/mL in the same buffer.

Techniques: Epifluorescence Microscopy, Construct, Electroporation, Fluorescence, Microscopy, Immunostaining

Journal: bioRxiv

Article Title: Molecular basis of Salla Disease: R39C Mutation Effects on the Lysosomal Transporter Sialin

doi: 10.64898/2026.04.20.719580

Figure Lengend Snippet: Mutagenesis experiments on the sialin R39 site. A and B) Wild-type (WT) or different mutated human sialin tagged with EGFP were transiently expressed in HeLa cells by electroporation. After two days, cells were fixed and analysed under fluorescence microscopy using LAMP1 immunostaining to detect late endosomes and lysosomes. In independent experiments, colocalisation was quantified using scatter plots of the sialin and LAMP1 pixel intensities. The graphs show the Pearson correlation coefficients normalised to that of WT (100%) in three different experiments for the mutants, except for R39C, 6 experiments, with 10 cells per experiment. The statistical analysis was performed by a one-sample t-test comparing the mean of the values for each mutant with a hypothetical mean value of 100: *= p ≤ 0.05, ** = p ≤ 0.01, *** = p ≤ 0.001, ****= p ≤ 0.0001). The red dotted line represents a Pearson coefficient of 0.5, above which we consider that sialin is targeted to lysosomes. It is calculated taking into consideration that the mean Pearson correlation coefficient for WT sialin is 0.73. C and D) Transport activity was measured in a whole-cell assay in which sialin was redirected to the plasma membrane by mutation of the lysosomal sorting motif to facilitate transport measurements (L22G L23G). Human L22G L23G sialin tagged with EGFP with/without mutations was transiently transfected by lipofection in HEK 293T cells. Human sialin (control) and its mutants were assayed for [ 3 H]Neu5Ac uptake at pH 5.0 in 3-6 independent experiments. The graphs show the transport activity relative to that of sialin L22G/L23G (100%) The statistical analysis was performed by a one-sample t-test comparing the mean of the values for each mutant with a hypothetical mean value of 100: * = p ≤ 0.05, ** = p ≤ 0.01, *** = p ≤ 0.001, ****= p ≤ 0.0001). E and F) Close-up views of ICH1 interactions in the completed and minimised models of the LO (E) and CO (F) conformations. Residues in ICH1 (green) are shown to interact with TM1 (orange), TM5 (purple), and other parts (grey) of sialin. Hydrogen bonding (green dashed lines), charge-charge (orange dashed lines), and apolar (purple dashed lines) interactions are shown for residues Y261 to L270 and R39. Hydrogen bonds between backbone atoms involved in the formation of alpha-helices are not shown and only polar hydrogens are displayed to improve visibility. Residues A26-C36 of the N-terminus are not shown to improve visibility.

Article Snippet: Coverslips were then incubated for at least 1 h with mouse anti-LAMP1 antibodies (H4A3; Developmental Studies Hybridoma Bank) at 0.75 μg/mL in blocking buffer, washed, and incubated with Cy3-conjugated donkey antimouse antibodies (Jackson ImmunoResearch) at 1.4 μg/mL or Alexa Fluor 555 goat antimouse antibodies (Invitrogen) at 2μg/mL in the same buffer.

Techniques: Mutagenesis, Electroporation, Fluorescence, Microscopy, Immunostaining, Activity Assay, Clinical Proteomics, Membrane, Transfection, Control