Journal: Alzheimer's Research & Therapy

Article Title: Intestinal epithelial Dicer1 regulates gut microbiome and Alzheimer’s pathology in App -knock-in mice

doi: 10.1186/s13195-025-01849-w

Figure Lengend Snippet: Deletion of Dicer1 in intestinal epithelial cells reduces BACE1 activity and increases LRP1 and ABCB1 expression in the brain of App -knock-in mice. Brains from 9-month-old App -knock-in littermate mice with (ko) and without (wt) deletion of epithelial Dicer1 were prepared for cell membrane components for β- and γ-secretase assays. Deletion of Dicer1 slightly but significantly reduced the activity of BACE1, but not γ-secretase ( A and B ; two-way ANOVA, n = 5 and 3 for wt and ko groups, respectively). Brain tissues were also homogenized for the isolation of capillaries. Quantitative Western blot of vessel lysates showed that deletion of Dicer1 significantly increased the protein levels of LRP1 and ABCB1, but not PDGFRβ and CD13 ( C - H ; t test, n = 6–8 per group). The brain tissues were further stained with fluorescence-conjugated CD68 and Aβ antibodies ( I ). Deletion of Dicer1 did not change the density of CD68-immunofluorescence around Aβ deposits in both cortex and hippocampus of App -knock-in mice ( J ; t test, n = 4–6 per group). Finally, the transcription of Neprilysin and Ide genes was determined by real-time PCR, which showed no effect of intestinal Dicer1 depletion on the expression of extracellular Aβ-degrading enzymes ( K and L ; t test, n = 4–8 per group)

Article Snippet: To investigate the microglial clearance of Aβ, brain tissue was incubated with a rabbit monoclonal antibody against CD68 (clone E3O7V; Cell Signaling Technology) after Aβ staining and visualized with Alexa488-conjugated goat anti-rabbit IgG (Thermo Fisher Scientific).

Techniques: Activity Assay, Expressing, Knock-In, Membrane, Isolation, Western Blot, Staining, Fluorescence, Immunofluorescence, Real-time Polymerase Chain Reaction