Journal: Frontiers in Cell and Developmental Biology

Article Title: Mitofusins are required for specialized mitochondrial morphology and function of rod photoreceptor cells

doi: 10.3389/fcell.2026.1724328

Figure Lengend Snippet: Abnormal mitochondrial morphologies in rod photoreceptor inner segments and synapses due to ablation of Mfn1 and Mfn2 at 1 month of age. (A) Representative electron micrographs of rod photoreceptor inner segments. Magnification = ×8,800. Scale bar = 1 micron. (B) Higher-magnification images of the regions outlined by red rectangles in panel (A) . (C) Representative electron micrographs of rod photoreceptor synapses. Magnification = ×8,800. (D) Quantification of the number of mitochondria in rod photoreceptor inner segments. (E) Quantification of the number of mitochondria in the rod photoreceptor synapse. (F) Quantification of the size of mitochondria in the rod photoreceptor synapse. Dots represent individual data points. Number in the parenthesis denotes the number of mice used in the experiment. Data is presented as mean±SD. *P < 0.05, ****P < 0.0001 by one-way ANOVA with post hoc Tukey’s test. (G,H) Photoreceptor cell degeneration in mice with rod-specific ablation of Mfn1 and Mfn2. Representative images of H&E-stained retinal sections of 1-, 2- and 3-month-old mice. Magnification = ×40. Scale bar = 20 microns (G) . Outer nuclear layer thickness (ONLT) ratios (H) . Note that Rho-Cre/Mfn1 flx/flx /Mfn2 flx/flx mice exhibit significant reduction of ONLT at 2 and 3 months of age. Number in the parenthesis denotes the number of mice used in the study. Data is presented as mean±SD. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 by two-way ANOVA with post hoc Tukey’s test.

Article Snippet: Rho-Cre mice (B6.Cg- Pde6b + Tg [Rho-icre]1Ck/Boc [JAX stock #015850, RRID: IMSR_JAX:015850]) , Mfn1 floxed mice ( Mfn1 flx/flx ; B6.129 [Cg]- Mfn1 tm2Dcc /J [JAX stock #026401, RRID: IMSR_JAX:026401]) , and Mfn2 floxed mice ( Mfn2 flx/flx ; B6.129 [Cg]- Mfn2 tm3Dcc /J [JAX stock #026525, RRID: IMSR_JAX:026525]) ( ) were purchased from The Jackson Laboratory.

Techniques: Staining

Journal: Frontiers in Cell and Developmental Biology

Article Title: Mitofusins are required for specialized mitochondrial morphology and function of rod photoreceptor cells

doi: 10.3389/fcell.2026.1724328

Figure Lengend Snippet: ERG analysis of Rho-Cre/Mfn1 flx/flx /Mfn2 flx/flx mice and age-matched WT controls. (A,B) Representative scotopic (rod-driven) ERG traces showing a- and b-waves (A) and c-waves (B) from 1-month-old WT (black) and Rho-Cre/Mfn1 flx/flx /Mfn2 flx/flx (blue) mice, and 2-month-old WT (yellow) and Rho-Cre/Mfn1 flx/flx /Mfn2 flx/flx (green) mice. (C–E) Quantification of scotopic ERG responses. Compared to WT controls, Rho-Cre/Mfn1 flx/flx /Mfn2 flx/flx mice exhibit a reduction in a-wave amplitude as early as 1 month of age (C) followed by a significant reduction in both a-wave and b-wave amplitude by 2 months (D) , and an age-dependent decline in c-wave amplitude (E) , consistent with progressive impairment of rod photoreceptor function and photoreceptor–RPE coupling. Number in the parenthesis denotes the number of mice used in the study. Data are presented as mean ± SEM, and statistical significance (*P < 0.05, **P < 0.01, ***P < 0.001) was determined using two-tailed Student’s t -tests.

Article Snippet: Rho-Cre mice (B6.Cg- Pde6b + Tg [Rho-icre]1Ck/Boc [JAX stock #015850, RRID: IMSR_JAX:015850]) , Mfn1 floxed mice ( Mfn1 flx/flx ; B6.129 [Cg]- Mfn1 tm2Dcc /J [JAX stock #026401, RRID: IMSR_JAX:026401]) , and Mfn2 floxed mice ( Mfn2 flx/flx ; B6.129 [Cg]- Mfn2 tm3Dcc /J [JAX stock #026525, RRID: IMSR_JAX:026525]) ( ) were purchased from The Jackson Laboratory.

Techniques: Two Tailed Test

Journal: Frontiers in Cell and Developmental Biology

Article Title: Mitofusins are required for specialized mitochondrial morphology and function of rod photoreceptor cells

doi: 10.3389/fcell.2026.1724328

Figure Lengend Snippet: Molecular pathways altered in the neural retina by rod-specific ablation of Mfn1 and Mfn2 . (A) Top10 enriched pathways were identified by Gene Set Enrichment Analysis (GSEA) and ranked by P value (pval) and adjusted P value (padj). NES stands for normalized enrichment score. (B) Overrepresentation analysis of the CEBPG_TARGET_GENES gene sets with the highest expression variation ratio. (C) Heatmap showing genes involved in mTORC1 signaling, amino acid (AA) metabolism, unfolded protein response (UPR), and C/EBPγ that are significantly enriched, and glycolysis-related genes that are significantly downregulated in the neural retina by rod-specific ablation of Mfn1 and Mfn2 . False discovery rate (FDR), logFC, and average expression (AvgExpr) are shown in the left column for each gene.

Article Snippet: Rho-Cre mice (B6.Cg- Pde6b + Tg [Rho-icre]1Ck/Boc [JAX stock #015850, RRID: IMSR_JAX:015850]) , Mfn1 floxed mice ( Mfn1 flx/flx ; B6.129 [Cg]- Mfn1 tm2Dcc /J [JAX stock #026401, RRID: IMSR_JAX:026401]) , and Mfn2 floxed mice ( Mfn2 flx/flx ; B6.129 [Cg]- Mfn2 tm3Dcc /J [JAX stock #026525, RRID: IMSR_JAX:026525]) ( ) were purchased from The Jackson Laboratory.

Techniques: Expressing

Journal: Frontiers in Cell and Developmental Biology

Article Title: Mitofusins are required for specialized mitochondrial morphology and function of rod photoreceptor cells

doi: 10.3389/fcell.2026.1724328

Figure Lengend Snippet: Metabolic changes in the neural retina resulting from rod-specific ablation of Mfn1 and Mfn2 . (A) Volcano plot showing differentially changed metabolites in the neural retina of Rho-Cre/Mfn1 flx/flx /Mfn2 flx/flx mice versus WT mice. (B) Heatmap showing significantly changed metabolites in the neural retina of Rho-Cre/Mfn1 flx/flx /Mfn2 flx/flx mice versus WT mice (P < 0.05). (C) Schematic diagram of pyrimidine and purine synthesis, and relative metabolite levels associated with nucleotide synthesis in Rho-Cre/Mfn1 flx/flx /Mfn2 flx/flx neural retina compared to WT neural retina. (D) Schematic diagram of glycolysis and TCA cycle, and relative metabolite levels associated with these pathways in Rho-Cre/Mfn1 flx/flx /Mfn2 flx/flx neural retina compared to WT neural retina. Data are presented as mean ± SD. Asterisks (*) indicate P < 0.05 significance by t-test. Five mice were used for each group in the study. Dots represent individual data points.

Article Snippet: Rho-Cre mice (B6.Cg- Pde6b + Tg [Rho-icre]1Ck/Boc [JAX stock #015850, RRID: IMSR_JAX:015850]) , Mfn1 floxed mice ( Mfn1 flx/flx ; B6.129 [Cg]- Mfn1 tm2Dcc /J [JAX stock #026401, RRID: IMSR_JAX:026401]) , and Mfn2 floxed mice ( Mfn2 flx/flx ; B6.129 [Cg]- Mfn2 tm3Dcc /J [JAX stock #026525, RRID: IMSR_JAX:026525]) ( ) were purchased from The Jackson Laboratory.

Techniques:

Journal: Frontiers in Cell and Developmental Biology

Article Title: Mitofusins are required for specialized mitochondrial morphology and function of rod photoreceptor cells

doi: 10.3389/fcell.2026.1724328

Figure Lengend Snippet: Identified changes in protein levels associated with pathways presumed to respond to mitochondrial fusion defects. (A) Schematic diagram of the glycolysis pathway of lactate synthesis from glucose through pyruvate in the cytosol of cells. (B) Western blot analysis of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), pyruvate kinase M2 (PKM2), and lactate dehydrogenase (LDH), which are related to glycolysis pathway in the neural retina of Rho-Cre/Mfn1 flx/flx /Mfn2 flx/flx mice versus WT mice. (C) Western blot analysis of each subunit comprising the complexes (Complex I (CI): NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 8 (NDUFB8), Complex II (CII): succinate dehydrogenase B (SDHB), Complex III (CIII): ubiquinol-cytochrome c reductase core protein 2 (UQCRC2), Complex IV (CIV): mitochondrially encoded cytochrome c oxidase I (MTCO1), Complex V (CV): ATP synthase F1 subunit alpha (ATP5A)) responsible for oxidative phosphorylation (OXPHOS). (D) Western blot analysis of another CII subunit, succinate dehydrogenase A (SDHA). (E) Schematic diagram of the substrate uptake and pathway toward mitochondrial β-oxidation. (F) Western blot analysis of carnitine-acylcarnitine translocase (CACT) and carnitine palmitoyl transferase II (CPT2), involved in mitochondrial β-oxidation. (G) Western blot analysis of mammalian target of rapamycin (mTOR) and phosphorylated-mTOR-S2448 (p-mTOR). Protein levels of p-mTOR were normalized by that of mTOR. Alpha-tubulin (TUB) served as the loading control for this Western blot experiments except for the result of p-mTOR. Data are presented as mean ± SD. Asterisks (*) indicates P < 0.05 significance following a significant difference detected by t-test. Six one-month-old mice were used in both groups in study. Dots represent individual data points. The protein size next to the immunoblot images denotes the size of the immunobands measured for this analysis.

Article Snippet: Rho-Cre mice (B6.Cg- Pde6b + Tg [Rho-icre]1Ck/Boc [JAX stock #015850, RRID: IMSR_JAX:015850]) , Mfn1 floxed mice ( Mfn1 flx/flx ; B6.129 [Cg]- Mfn1 tm2Dcc /J [JAX stock #026401, RRID: IMSR_JAX:026401]) , and Mfn2 floxed mice ( Mfn2 flx/flx ; B6.129 [Cg]- Mfn2 tm3Dcc /J [JAX stock #026525, RRID: IMSR_JAX:026525]) ( ) were purchased from The Jackson Laboratory.

Techniques: Western Blot, Phospho-proteomics, Control

Journal: Materials Today Bio

Article Title: A dual-responsive CO-releasing nanogel ameliorates retinal ischemia–reperfusion injury by restoring mitochondrial homeostasis and attenuating cGAS-STING pathway activation

doi: 10.1016/j.mtbio.2026.102974

Figure Lengend Snippet: COPN restores mitochondrial quality control and interrupts the ROS‒cGAS‒inflammation axis in OGD/R-treated R28 cells. a , TEM images showing changes in the mitochondrial ultrastructure of R28 cells subjected to various treatments (PBS, PDNs, COPN-L, and COPN-H) after OGD/R. Scale bar: 500 nm b , Quantitative analyses of mitochondrial length and number in R28 cells as indicated in a . c , Representative fluorescence images showing JC-1 staining of the mitochondrial Δψm: aggregates (red) indicate healthy mitochondria, whereas monomers (green) represent depolarized mitochondria. Nuclei were stained with DAPI (blue). Scale bar: 50 μm d , Intracellular ATP content assay revealing improved energy production after COPN treatment under OGD/R stress conditions. e , mRNA expression analysis of mitochondrial dynamic regulatory genes (Opa1, Mfn2, Drp1, and Fis1) and mitochondrial DNA transcription levels (mt-ND1 and mt-COX1). f , Quantitative analysis of the JC-1 fluorescence ratio (aggregates/monomers) and mitochondrial ROS levels (MitoSOX staining). g–h , Western blot analysis of proteins involved in mitochondrial autophagy (Pink1, Parkin, and P62) (g) and mitochondrial fusion/fission (Opa1, Mfn2, Mfn1, Drp1, and Fis1) (h) . i , Confocal fluorescence microscopy images of mitochondria (green, MitoTracker) and lysosomes (red, LysoTracker) in R28 cells after different treatments. Nuclei were stained with Hoechst (blue). Scale bar: 50 μm ∗ ∗∗∗P < 0.0001. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Article Snippet: The following primary antibodies were used: Drp1 (CST, #8570, 1:1000, ∼80 kDa), Fis1 (Proteintech, 10956-1-AP, 1:1000, ∼17 kDa), Mfn1 (Abcam, ab104274, 1:1000, ∼84 kDa), Mfn2 (CST, #9482, 1:1000, ∼86 kDa), Opa1 (CST, #80471, 1:1000, ∼100–120 kDa), Pink1 (CST, #6946, 1:1000, ∼63 kDa), cGAS (CST, #15102, 1:1000, ∼60 kDa), STING (CST, #13647, 1:1000, ∼42–45 kDa), TBK1 (CST, #3013, 1:1000, ∼84 kDa), p-TBK1 (CST, #5483, 1:1000, ∼84 kDa), COX IV (Abcam, ab14744, 1:2000, ∼17 kDa), β-actin (Proteintech, 66009-1-Ig, 1:5000, ∼43 kDa), and GAPDH (Proteintech, 60004-1-Ig, 1:5000, After washing, the membranes were incubated with HRP-conjugated secondary antibodies (goat anti-rabbit or goat anti-mouse IgG, CST, 1:5000) for 1 h at room temperature.

Techniques: Control, Fluorescence, Staining, Expressing, Western Blot, Microscopy