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