Journal: Nature immunology

Article Title: Microglia use TAM receptors to detect and engulf amyloid beta plaques

doi: 10.1038/s41590-021-00913-5

Figure Lengend Snippet: ( a ) Representative video stills from two-photon imaging of microglia (GFP signal, white) and amyloid plaques (MX04 signal, red) in 16 mo APP/PS1 and APP/PS1Axl −/− Mertk −/− cortex. ( b ) Imaris surface builds of microglial volumes at 0–5μm (white) and 5–20μm (green) from the edge of nearest plaque (red) in APP/PS1 and APP/PS1Axl −/− Mertk −/− cortex, representative of image volumes in cortices of n = 3 APP/PS1 and 5 APP/PS1 Axl −/− Mertk −/− mice. Scale bars: 30μm. ( c ) Distribution of distances of microglial cell body centroids from the edge of Aβ plaques in APP/PS1 and APP/PS1Axl −/− Mertk −/− cortex. 22 and 37 plaques were investigated from 3 and 4 mice for APP/PS1 and APP/PS1Axl −/− Mertk −/− , respectively. ( d ) Primary microglial processes per nearest plaque for microglia <5μm from plaques (PAM) in APP/PS1 ( A/PS ) and APP/PS1Axl −/− Mertk −/− ( A/PS A/M −/− ) cortex. ( e ) Summed length of primary microglial processes per nearest plaque for PAM in APP/PS1 and APP/PS1Axl −/− Mertk −/− cortex. ( f ) Process polarization to nearest plaque (ratio of summed length of primary processes oriented toward plaque to summed length of all primary processes) for NPAM (microglia >20μm from plaques) in APP/PS1 and APP/PS1Axl −/− Mertk −/− cortex. ( g ) Process motility for cortical PAM, NPAM, and non-diseased microglia in mice of the indicated genotypes. Data points are from 7–29 representative plaques from n = 3 mice from both genotypes ( d – f ), and 18–52 microglia from 2 (WT and Axl −/− Mertk −/− ) and 3 ( APP/PS1 and APP/PS1Axl −/− Mertk −/− ) mice ( g ). Data represented as mean ±1 STD. Mann-Whitney test ( d-f ) and Kruskal Wallis test followed by Dunn’s multiple comparison test ( g ).

Article Snippet: Created surfaces were then used to determine distance of the centroid of individual GFP surfaces to the closest edge of MX04 objects with the build-in MATLAB function in Imaris.

Techniques: Imaging, MANN-WHITNEY

Journal: Nature immunology

Article Title: Microglia use TAM receptors to detect and engulf amyloid beta plaques

doi: 10.1038/s41590-021-00913-5

Figure Lengend Snippet: ( a ) Distribution of distance of microglial cell body centroids, in 2μm bins, from the edge of MX04-labeled Aβ plaques with diameters of 10–15μm in APP/PS1 (gray) and APP/PS1Axl −/− Mertk −/− (red) cortex. Values obtained for 56 and 23 plaques from 3 and 4 mice for APP/PS1 and APP/PS1Axl −/− Mertk −/− , respectively. ( b ) Number of imaged GFP + primary processes per PAM (microglia <5μm from plaques) in APP/PS1 (gray, A/PS ) and APP/PS1Axl −/− Mertk −/− (red, A/PS A/M −/− ) cortex. ( c ) Summed length of primary microglial processes per PAM in APP/PS1 (gray) and APP/PS1Axl −/− Mertk −/− (red) cortex. ( d ) Process polarization ratio to nearest plaque per NPAM (microglia >20μm from plaques; see Materials and Methods) in APP/PS1 (gray) and APP/PS1Axl −/− Mertk −/− (red) cortex. ( e ) Quantification of microglial cell density in the cortex of 16 mo APP/PS1 (gray) and APP/PS1Axl −/− Mertk −/− (red) mice for microglia 0–10 μm, 10–20 μm, and >20 μm from the edge of the nearest plaque. Data points are from 45–129 cells (PAM) investing 10–29 plaques ( b , c ), and 21–49 cells peripheral to 7–24 plaques ( d ) from n = 3 mice per genotype ( b – d ). Points in e represent 3–5 imaging volumes from 3 APP/PS and 4 APP/PS1Axl −/− Mertk −/− mice. Two-way ANOVA with Sidak’s multiple comparison test ( a, e ) and Mann-Whitney’s test ( b-d ). Data are represented as mean ±1 STD.

Article Snippet: Created surfaces were then used to determine distance of the centroid of individual GFP surfaces to the closest edge of MX04 objects with the build-in MATLAB function in Imaris.

Techniques: Labeling, Imaging

Journal: Nature immunology

Article Title: Microglia use TAM receptors to detect and engulf amyloid beta plaques

doi: 10.1038/s41590-021-00913-5

Figure Lengend Snippet: ( a , b ) MX04-labeled Aβ plaque material engulfed within GFP + microglia, imaged in vivo , in 16 mo. APP/PS1 ( A/PS ) versus APP/PS1Axl −/− Mertk −/− ( A/PS A/M −/− ) cortex, normalized to imaging volume ( a ) and the volume of GFP + cells ( b ). ( c ) Representative images of the halo of LAMP1 + dystrophic membranes (green, lower panels) that surround 6E10 + plaques in 12 mo APP/PS1 ( A/PS ; left) versus APP/PS1Axl −/− Mertk −/− ( A/PS A/M −/− ; right) cortex. Arrowheads mark weakly-staining, diffuse 6E10 + plaques, which are more common in the APP/PS1Axl −/− Mertk −/− brain (see also ). Scale bar: 10μm. ( d ) Quantification of the ratio of LAMP1 + area to 6E10 + plaque area across all plaque sizes, both dense-core and diffuse. ( e ) Quantification of ratio RTN3 + area to 6E10 + plaque area across all plaque sizes, both dense-core and diffuse. Data are 13–15 volumetric images from n= 3 and 4 mice for APP/PS1 and APP/PS1Axl −/− Mertk −/− , respectively ( a – b ). Data are 94–113 plaques ( d ) and 56–95 plaques ( e ) investigated from N ≥ 3 sections per mouse from n = 3 mice of each genotype. Mann-Whitney test ( a , b , d , e ). Data represented as mean ±1 STD.

Article Snippet: Created surfaces were then used to determine distance of the centroid of individual GFP surfaces to the closest edge of MX04 objects with the build-in MATLAB function in Imaris.

Techniques: Labeling, In Vivo, Imaging, Staining, MANN-WHITNEY

Journal: Nature immunology

Article Title: Microglia use TAM receptors to detect and engulf amyloid beta plaques

doi: 10.1038/s41590-021-00913-5

Figure Lengend Snippet: ( a ) Representative two-photon imaging volumes (X and Y 350μm, Z 300μm) of MX04-labeled plaques in 16 mo APP/PS1 and APP/PS1Axl −/− Mertk −/− cortex, as observed in image volumes in cortices of n = 3 ( APP/PS1 ) and 5 ( APP/PS1 Axl −/− Mertk −/− ) mice. Scale bar: 30μm. Representative sagittal sections from 12 mo APP/PS1 and APP/PS1Axl −/− Mertk −/− brains from at least 3 independent replicates, stained for dense-core plaques with thioflavin S (Thio S), quantified in d and , . Scale bar: 1mm. ( c ) Quantification (see ) of Thio S-labeled dense-core Aβ plaque density, for cross-sectional plaque areas of all sizes, in APP/PS1 (gray) and APP/PS1Axl −/− Mertk −/− (red) cortex over time. Boxed data at 12 mo are detailed in d . n=4–8 per genotype per time point. ( d ) Thio S-labeled plaque density in cortex (of APP/PS1 (gray) and APP/PS1Axl −/− Mertk −/− (red) mice at 12 mo. Data points represent plaque density in n= 6 APP/PS1 and 8 APP/PS1Axl −/− Mertk −/− mice of the indicated genotypes averaged from N = 5 cortical sections of each brain. Student’s t-test ( c, d ). Data represented as mean ±1 STD.

Article Snippet: Created surfaces were then used to determine distance of the centroid of individual GFP surfaces to the closest edge of MX04 objects with the build-in MATLAB function in Imaris.

Techniques: Imaging, Labeling, Staining