Journal: bioRxiv

Article Title: Dying oligodendrocytes persist without mitochondria

doi: 10.64898/2026.01.19.699752

Figure Lengend Snippet: a , FIS1 immunostaining in fixed tissue from the cerebral cortex of a Cspg4 -CreER; PhAM transgenic mouse. Note that CAII-labeled oligodendrocytes show the strongest FIS1 signal and stand out from the surrounding cells. b , Representative images of a PDGFRA-labeled OPC (top) and CAII-labeled oligodendrocyte (bottom) along with their mito-Dendra2 and FIS1 signals. Boxes indicate regions shown at higher magnification in single optical z-sections. Quantification of FIS1 intensity within the mitochondrial ROIs from 23 PDGFRA + and 23 CAII + cells ( n = 4 mice, unpaired two-tailed t test). c , Experimental timeline and genetic strategy for conditional deletion of Fis1 and expression of mito-Dendra2 and tdTomato in Cspg4 lineage cells. Two doses of tamoxifen were injected postnatally at P5 and P7 to induce Cre recombination, and experiments were performed 3-4 weeks later. d , Representative images of PDGFRA + cells in the cKO tissue. A subset of the cells lacks FIS1 (#1-4), whereas the FIS1 signal is present in the others (#5-6). Scale bars in cropped images represent 2 µm. Percent of PDGFRA + cells lacking FIS1 immunoreactivity in control and cKO tissue. e , Representative images of CAII + cells in the cKO tissue. A subset of them lacks FIS1 (#1, #2, #5), whereas FIS1 signal is present in the others (#3, #4). Percent of CAII + cells lacking FIS1 immunoreactivity in control and cKO tissue. In d and e , n = 4 control and 6 cKO mice, unpaired two-tailed t test with Welch’s correction for unequal variance. f , Representative fields of view from control and cKO tissue showing CAII and FIS1 immunostaining. Quantification of cortical oligodendrocyte density ( n = 4 control and 6 cKO mice, unpaired two-tailed t test). g , Examples of FIS1-negative oligodendrocytes with disrupted mitochondria in the cKO tissue, along with adjacent FIS1-positive cells. In d, e , and g , arrowheads point at FIS1-negative cells, and arrows point at FIS1-positive cells and their mitochondria. dpi: days post tamoxifen injection. Data are shown as mean ± SEM.

Article Snippet: Genotyping of the Fis1 loxP allele was done via Transnetyx.

Techniques: Immunostaining, Transgenic Assay, Labeling, Two Tailed Test, Expressing, Injection, Control

Journal: bioRxiv

Article Title: Dying oligodendrocytes persist without mitochondria

doi: 10.64898/2026.01.19.699752

Figure Lengend Snippet: a , Experimental timeline showing tamoxifen injections at P5 and P7 and tissue collection at P100. b , Example of a FIS1-positive oligodendrocyte adjacent to a FIS1-negative oligodendrocyte. Note the condensed nucleus and lost mitochondria in the latter. c , Representative images of CA-II labeled oligodendrocytes and FIS1 immunostaining in control and cKO tissue. Quantification of the percentage of CAII + cells lacking FIS1 immunoreactivity and CAII + cell density ( n = 4 control and 7 cKO mice, unpaired two-tailed t test; Welch’s correction for unequal variance was applied for the first graph, left to right). In (b) and (c) , arrows point at FIS1-positive oligodendrocytes, and arrowheads point at FIS1-negative oligodendrocytes. d , Representative images of ASPA, CNP, and MBP staining across control and cKO groups, along with quantification of cell densities and MBP area coverage ( n = 4 control and 7 cKO mice, unpaired two-tailed t test; Welch’s correction was applied for the MBP graph). Arrows point at CNP + cells. e , Representative images of BCAS1 and MBP staining, along with BCAS1 + cell density and BCAS1 signal coverage within MBP + structures across the two groups ( n = 4 control and 7 cKO mice, unpaired two-tailed t test; Welch’s correction was applied for the second graph, left to right). f , Representative images of PDGFRA staining along with PDGFRA + cell densities in control and cKO mice ( n = 4 control and 7 cKO mice, unpaired two-tailed t test). Data are shown as mean ± SEM.

Article Snippet: Genotyping of the Fis1 loxP allele was done via Transnetyx.

Techniques: Labeling, Immunostaining, Control, Two Tailed Test, Staining

Journal: bioRxiv

Article Title: Dying oligodendrocytes persist without mitochondria

doi: 10.64898/2026.01.19.699752

Figure Lengend Snippet: a , Experimental timeline and genetic strategy for conditional deletion of Fis1 and expression of mito-Dendra2 in myelinating cells. Eight doses of tamoxifen were administered starting at ∼P70, and experiments were performed 2 months after the first injection. b , Representative images showing oligodendrocytes in the control and cKO tissue, and heterogeneous phenotypes of FIS1-negative oligodendrocytes. Automated quantification of the percentage of CAII-labeled oligodendrocytes lacking FIS1 immunoreactivity ( n = 4 control and 5 cKO mice, unpaired two-tailed t test). c , Representative images of CNP-labeled oligodendrocytes and their mitochondria across control and cKO groups. Note the lack of mito-Dendra2 signal in a subset of cells in the cKO tissue. Quantification of the percentage of CNP + cells with low or no mito-Dendra2 signal ( n = 3 control and 4 cKO mice, unpaired two-tailed t test). d , Zoomed in examples of oligodendrocytes and their nuclei from fields of view in (c) . Quantification of soma and nucleus area ( n = 3 control and 4 cKO mice, unpaired two-tailed t test; Welch’s correction for unequal variance was applied for the first graph, left to right). e, f , Examples of CNP-labeled oligodendrocytes and TOM20 immunostaining. Note that TOM20 signal corresponds to the presence or absence of the mito-Dendra2 signal, with some contributions from surrounding cells in single optical sections. Quantification of mito-Dendra2 and TOM20 mean fluorescence intensity in the somas of CNP-labeled oligodendrocytes ( n = 3 control and 4 cKO mice, unpaired two-tailed t test). In b-f , arrows point at cells with normal mito-Dendra2 signal, and arrowheads point at cells with low or no mito-Dendra2 signal. g , ASPA + , CAII + , and CNP + cell density and MBP area coverage in control and cKO groups ( n = 4 control and 5 cKO mice, unpaired two-tailed t test). Data are shown as mean ± SEM.

Article Snippet: Genotyping of the Fis1 loxP allele was done via Transnetyx.

Techniques: Expressing, Injection, Control, Labeling, Two Tailed Test, Immunostaining, Fluorescence

Journal: bioRxiv

Article Title: Dying oligodendrocytes persist without mitochondria

doi: 10.64898/2026.01.19.699752

Figure Lengend Snippet: a , Representative images of P62 immunostaining in oligodendrocytes from control and cKO, Plp1 -CreER; PhAM; Fis1 loxP/loxP mice. Quantification of P62 mean fluorescence intensity per animal ( n = 3 control and 4 cKO mice, unpaired two-tailed t test) and per cell ( n = 39 cells from 3 control mice; 20 cells with normal mito-Dendra2, and 29 cells with low to no mito-Dendra2 from 4 cKO mice, Welch ANOVA with Dunnett’s T3 multiple comparisons test). Arrows point at CNP + cells with normal mitochondria, and arrowheads point at CNP + cells with low or no mito-Dendra2 signal. b , Representative images of ASPA and SERPINA3N immunostaining. Quantification of ASPA and SERPINA3N-dual labeled cells (arrowheads) and their proportion of total oligodendrocytes ( n = 4 control and 5 cKO mice, unpaired two-tailed t test with Welch’s correction for unequal variance). c , Representative image of ASPA and SERPINA3N immunostaining in the cKO tissue, along with quantification of dual-labeled ASPA and SERPINA3N population grouped by mito-Dendra2 presence (normal, low, or absent, n = 3 control and 4 cKO mice, unpaired two-tailed t test; Welch’s correction for unequal variance was applied to the second and third graphs, left to right). Data are shown as mean ± SEM.

Article Snippet: Genotyping of the Fis1 loxP allele was done via Transnetyx.

Techniques: Immunostaining, Control, Fluorescence, Two Tailed Test, Labeling

Journal: Cells

Article Title: Cys340Ser Mutation Abolishing S-Nitrosylation Drives GRK2 Mitochondrial Localization and Dysfunction

doi: 10.3390/cells15050458

Figure Lengend Snippet: Group comparison of mitochondrial Drp1 ( A ) and Fis1 ( B ) expressions. Statistical significance was determined by ANOVA followed by Bonferroni’s post hoc test. Data are shown as mean ± SEM; ns, p = 0.2021 for Drp1; *, p < 0.05 ( p = 0.0041) for Fis1 ( n = 5–7 per group). Representative immunoblots demonstrating Drp1 and Fis1 protein levels in mitochondrial fractions and total cell lysates of AC16 cells infected with Ad.GFP or Ad.GRK2-C340S under normoxic or hypoxia/reoxygenation (H/R) conditions. VDAC served as a mitochondrial loading control and GAPDH served as a total protein marker. Densitometric analysis was performed using Li-Cor Image Studio software and normalized to the respective loading controls. All samples included in each comparative analysis were run on the same gel. Cropped blots are presented for clarity; uncropped blots with molecular weight markers are provided in .

Article Snippet: The primary antibodies used were as follows: GRK2 (13990-1-AP; ProteinTech, Rosemont, IL, USA), GRK2 (05-465; Sigma Aldrich, St. Louis, MO, USA), Drp1 (8570; Cell Signaling Technology, Danvers, MA, USA), Fis1 (32525; Cell Signaling Technology, Danvers, MA, USA), Mfn1 (14739; Cell Signaling Technology, Danvers, MA, USA), Mfn2 (11925; Cell Signaling Technology, Danvers, MA, USA), Opa1 (80471; Cell Signaling Technology), Pink (6946; Cell Signaling Technology, Danvers, MA, USA), Parkin (4211; Cell Signaling Technology, Danvers, MA, USA), LC3 (3868; Cell Signaling Technology, Danvers, MA, USA), Tom20 (42406; Cell Signaling Technology, Danvers, MA, USA), VDAC1 (sc-390996; Santa Cruz Biotechnology, Dallas, TX, USA), and GAPDH (sc-32233; Santa Cruz Santa Cruz Biotechnology, Dallas, TX, USA).

Techniques: Comparison, Western Blot, Infection, Control, Marker, Software, Molecular Weight