Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Jun 10;4(1):711.
doi: 10.1038/s42003-021-02259-y.

Microglial metabolism is a pivotal factor in sexual dimorphism in Alzheimer's disease

Marie-Victoire Guillot-Sestier #  1 , Ana Rubio Araiz #  1 , Virginia Mela #  1   2 , Aline Sayd Gaban #  1 , Eoin O'Neill #  1 , Lisha Joshi  3 , Edward T Chouchani  4   5 , Evanna L Mills  4   5 , Marina A Lynch  6
Affiliations

Microglial metabolism is a pivotal factor in sexual dimorphism in Alzheimer's disease

Marie-Victoire Guillot-Sestier et al. Commun Biol. .

Abstract

Age and sex are major risk factors in Alzheimer's disease (AD) with a higher incidence of the disease in females. Neuroinflammation, which is a hallmark of AD, contributes to disease pathogenesis and is inexorably linked with inappropriate microglial activation and neurodegeneration. We investigated sex-related differences in microglia in APP/PS1 mice and in post-mortem tissue from AD patients. Changes in genes that are indicative of microglial activation were preferentially increased in cells from female APP/PS1 mice and cells from males and females were morphological, metabolically and functionally distinct. Microglia from female APP/PS1 mice were glycolytic and less phagocytic and associated with increased amyloidosis whereas microglia from males were amoeboid and this was also the case in post-mortem tissue from male AD patients, where plaque load was reduced. We propose that the sex-related differences in microglia are likely to explain, at least in part, the sexual dimorphism in AD.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1. Sex-related differential expression of microglial markers in APP/PS1 and WT mice.
a–c The heat maps, generated from a Nanostring quantitative assay platform, represent the experimental groups and individual mRNA transcripts in columns and rows, respectively. Genes that have been reported to be upregulated in ARMs and/or DAMs (a) or in other neuroinflammatory conditions (b) and genes that describe the homeostatic state (c), are shown. Expression is displayed on a log 10 scale from blue (low expression) to red (high expression). d Volcano plots of mRNA expression showing significant genotype-related differences (p < 0.01 indicated by the dotted line) are depicted. e, f Significant genotype × sex interactions in Tyrobp and Ccl6 (p < 0.05) and significant main effects of genotype (p < 0.001) and sex (p < 0.05 or p < 0.01) were identified in mean data from Nanostring analysis and RT-PCR for Tyrobp, Ctsd, Ccl6, and Trem2. Post hoc analysis revealed significant genotype-related increases (*p < 0.05; **p < 0.01) and significant increases in Tyrobp, Ctsd, and Ccl6 in microglia from female, compared with male, APP/PS1 mice (§p < 0.05; §§p < 0.01; §§§p < 0.001) and in several other indicators of microglial activation as indicated in Supplementary Fig. 1. Data, expressed as means ± SEM (n = 5 (PCR data) or 6 (Nanostring data)), were analysed by 2-way ANOVA and Tukey’s post hoc multiple comparison test. The changes in e and f are relative to values in WT males. Additional related data are presented in Supplementary Figs. 1 and 2.
Fig. 2
Fig. 2. Evidence of sex-related changes in microglial morphology in APP/PS1 and WT mice.
a–c CD68 mRNA (a), the co-localisation of Iba1+ CD68+ pixels (b) and the proportion of rod-shaped microglia (c) were increased in the hippocampus (and cortex, see Supplementary Fig. 2) of APP/PS1, compared with WT, mice (***p < 0.001) and a further increase was observed in female, compared with male, APP/PS1 mice (§p < 0.05; §§§p < 0.001). d 3D surface plot reconstructions show that male cells adopt an amoeboid morphology (scale bar = 5 μm). e A genotype-related increase in soma size was evident in male and female mice (***p < 0.001; d) but soma size was reduced in female WT and APP/PS1 mice compared with male counterparts (+++p < 0.001; §§§p < 0.001, respectively). f A significant main effect of genotype in circularity (p < 0.001) was observed and the mean value was significantly increased in male APP/PS1, compared with WT, mice (*p < 0.05). g–i Cell perimeter, area and pixels/cell were increased WT male, compared with the female mice (+p < 0.05; ++p < 0.01). Genotype-related decreases were observed in female mice (***p < 0.001) and changes in cell complexity were identified mainly in microglia from female mice (Supplementary Fig. 2). Data, expressed as means ± SEM (n = 5 or 6 mice/group with analysis of between 96 and 128 cells), were analysed by 2-way ANOVA and Tukey’s post hoc multiple comparison test. In the case of CD68 mRNA, data were retrospectively calculated from several previous experiments and assessed by sex (n = 15) (APP female; 16 WT female; 17 APP male; 19 WT male).
Fig. 3
Fig. 3. Evidence of sex-related differences in morphology of microglia distal from plaques.
a 3D reconstructions showed differences in morphology in peri-plaque and distal microglia (scale bars = 50 and 5 μm in the main image and high-magnification image, respectively). b Cell perimeter, area, diameter (59–89 cells analysed) and pixels/cell (42–63 cells analysed) were markedly reduced in peri-plaque compared with distal microglia and these measures were increased in distal microglia from female, compared with male, mice (§§§p < 0.001). Data, expressed as means ± SEM (n = 5 or 6 mice/group), were analysed by 2-way ANOVA and Tukey’s post hoc multiple comparison test.
Fig. 4
Fig. 4. Microglia from female APP/PS1 mice shift their metabolism towards glycolysis.
a, b NanoString analysis indicated that Hk2, Pfkfb3, Gapdh, Pgk1 and Pgam1 were upregulated in cells from APP/PS1, compared with WT, mice (*p < 0.05; **p < 0.01; ***p < 0.001; n = 6) with some changes significantly greater in female APP/PS1 mice compared with males (§p < 0.05; §§p < 0.01). Expression is displayed on a log 10 scale from blue (low expression) to red (high expression). c ECAR was increased in microglia from female APP/PS1 mice with a significant increase in glycolysis in microglia from female APP/PS1 (n = 11), compared with female WT (n = 14), mice (***p < 0.001) and male APP/PS1 mice (§§p < 0.01; n = 4) and also male WT mice (n = 8). d Lactate was increased in microglia from female APP/PS1 mice (n = 6) compared with male APP/PS1 mice (§p < 0.05; n = 5). e, f No genotype- or sex-related changes were observed in other intermediate metabolites of glycolysis (n = 6 except for DHAP where n = 5). Minimal changes were observed in intermediate metabolites of the TCA (Supplementary Fig. 3) although marked sex-related differences were identified in amino acids generated from intermediate metabolites of glycolysis and the TCA (Supplementary Fig. 3). The changes in b, d and f are relative to values in WT males. Data, expressed as means ± SEM, were analysed by 2-way ANOVA and Tukey’s post hoc multiple comparison test.
Fig. 5
Fig. 5. Cytosolic PFKFB3 is increased in microglia from female APP/PS1 mice.
a Representative images of PFKFB3 staining in Iba1+ microglia in sections from the hippocampus. (Scale bar = 100 μm; magnified image, 20 μm). b A genotype-related increase in PFKFB3 staining was found in sections prepared from APP/PS1, compared with WT, mice (p < 0.05; main effect of genotype) though post hoc analysis identified no significant changes. Values are presented as means ± SEM (n = 6 for male WT and APP/PS1 mice, n = 5 and 7 for female WT and APP/PS1 mice, respectively). c Representative images of PFKFB3 staining in isolated microglia. Scale bars: main figure, 50 μm; magnified image, 10 μm. d The percentage of PFKFB3 staining in the cytosol was significantly increased while nuclear staining was significantly decreased in microglia from female APP/PS1 mice compared with male APP/PS1 mice, and the ratio nuclear:cytosolic staining (expressed as voxels) was similarly decreased (§p < 0.05; §§p < 0.01; n = 9, 4, 9, 12 for male WT and APP/PS1 and male WT and APP/PS1 mice, respectively). Data, expressed as means ± SEM, were analysed by 2-way ANOVA and Tukey’s post hoc multiple comparison test.
Fig. 6
Fig. 6. Differential effect of sex on microglial function.
a Aβ uptake into isolated microglia from female APP/PS1 mice was significantly reduced compared with microglia from WT mice (*p < 0.05; n = 7, 4, 6, 5 for male WT and APP/PS1 and male WT and APP/PS1 mice, respectively). b ThioS-stained Aβ plaque number and area were significantly increased in hippocampal sections from female, compared with male, APP/PS1 mice (*p < 0.05; n = 5 and 8 for male and female mice, respectively). c Phagolysosomal loading with Aβ was significantly greater in microglia from female APP/PS1 mice compared with males (*p < 0.05; n = 6 and 8 for male and female mice, respectively). d, e NanoString analysis indicated that lysosomal genes were upregulated in microglia prepared from female APP/PS1 mice compared with the other groups (d). Analysis of the mean data, relative to values in WT males, indicated that there were significant increases in Lamp2, Myo5A, Rab3A, Ctsl, Cla, Galc, Ppt1 and Srgn in microglia from female APP/PS1 mice compared with female WT mice (*p < 0.05; **p < 0.01; ***p < 0.001) and compared with male APP/PS1 mice (§p < 0.05; §§p < 0.01; n = 6; e). Data, expressed as means ± SEM, were analysed by 2-way ANOVA and Tukey’s post hoc multiple comparison test except for b and c when the Student’s t-test for independent means was used to evaluate data.
Fig. 7
Fig. 7. Changes in microglial morphology in post-mortem parietal cortical tissue from AD patients are sex-related.
a, b Representative images of DAB-stained microglia, showing marked process retraction (a; scale bar = 100 μm; magnified image, 50 μm) and a preponderance of amoeboid microglia (b; scale bar = 200 μm; magnified image, 50 μm) in sections of parietal cortex from male AD patients compared with females, in which many rod-shaped microglia were identified. c Representative masks and 3D representations were used to analyse morphological features. d Significant disease × sex interactions in circularity, perimeter, Feret’s diameter and cell density were observed (p < 0.05). Post hoc analysis revealed significant increases in circularity and cell density and significant decreases in cell perimeter and Feret’s diameter in microglia from male AD patients compared with controls (**p < 0.01; ***p < 0.001) and also in male, compared with female, AD patients (§p < 0.05). Data, expressed as means ± SEM (n = 4 for controls or 5 for AD), were analysed by 2-way ANOVA and Tukey’s post hoc multiple comparison test.
Fig. 8
Fig. 8. Amyloid accumulation is significantly greater in post-mortem tissue from female compared with male AD patients.
a Congo red staining in the parenchyma was more pronounced in parietal cortical tissue from female, compared with male, AD patients and plaque area was significantly increased (*p < 0.05; n = 5; scale bar = 100 μm). b Vascular amyloid staining was significantly greater in sections prepared from male AD patients compared with females (***p < 0.001; n = 5; scale bar = 400 μm). c CD68 immunoreactivity was significantly greater in parietal cortex from male, compared with the female, AD patients (*p < 0.05, 1-tailed t-test; n = 4 except for AD females where n = 5; scale bar = 100 μm; magnified image, 50 μm). Data, expressed as means ± SEM (n = 5), were analysed by the Student’s t-test (1-tailed t-test for CD68 and 2-tailed for amyloid staining).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Hammond TR, et al. Single-cell RNA sequencing of microglia throughout the mouse lifespan and in the injured brain reveals complex cell-state changes. Immunity. 2019;50:253–271 e256. doi: 10.1016/j.immuni.2018.11.004. - DOI - PMC - PubMed
    1. Mangold CA, et al. Sexually divergent induction of microglial-associated neuroinflammation with hippocampal aging. J. Neuroinflamm. 2017;14:141. doi: 10.1186/s12974-017-0920-8. - DOI - PMC - PubMed
    1. Krasemann S, et al. The TREM2-APOE pathway drives the transcriptional phenotype of dysfunctional microglia in neurodegenerative diseases. Immunity. 2017;47:566–581 e569. doi: 10.1016/j.immuni.2017.08.008. - DOI - PMC - PubMed
    1. Zhao N, et al. Alzheimer’s risk factors age, APOE genotype, and sex drive distinct molecular pathways. Neuron. 2020;106:727–742 e726. doi: 10.1016/j.neuron.2020.02.034. - DOI - PMC - PubMed
    1. Keren-Shaul H, et al. A unique microglia type associated with restricting development of Alzheimer’s disease. Cell. 2017;169:1276–1290 e1217. doi: 10.1016/j.cell.2017.05.018. - DOI - PubMed

Publication types