Translational profiling identifies sex-specific metabolic and epigenetic reprogramming of cortical microglia/macrophages in APPPS1-21 mice with an antibiotic-perturbed-microbiome
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Updated: Aug 3, 2026
Isolation of Region-specific Microglia from One Adult Mouse Brain Hemisphere for Deep Single-cell RNA Sequencing
Published on: December 3, 2019
Shabana M Shaik1, Yajun Cao1, Joseph V Gogola1
1Dept. of Neurobiology, The University of Chicago, Chicago, IL, USA.
Background:
Microglia, the brain-resident macrophages perform immune surveillance and engage with pathological processes resulting in phenotype changes necessary for maintaining homeostasis. In preceding studies, we showed that antibiotic-induced perturbations of the gut microbiome of APPPS1-21 mice resulted in significant attenuation in Aβ amyloidosis and altered microglial phenotypes that are specific to male mice. The molecular events underlying microglial phenotypic transitions remain unclear. Here, by generating 'APPPS1-21-CD11br' reporter mice, we investigated the translational state of microglial/macrophage ribosomes during their phenotypic transition and in a sex-specific manner.
Methods:
Six groups of mice that included WT-CD11br, antibiotic (ABX) or vehicle-treated APPPS1-21-CD11br males and females were sacrificed at 7-weeks of age (n = 15/group) and used for immunoprecipitation of microglial/macrophage polysomes from cortical homogenates using anti-FLAG antibody. Liquid chromatography coupled to tandem mass spectrometry and label-free quantification was used to identify newly synthesized peptides isolated from polysomes.
Results:
We show that ABX-treatment leads to decreased Aβ levels in male APPPS1-21-CD11br mice with no significant changes in females. We identified microglial/macrophage polypeptides involved in mitochondrial dysfunction and altered calcium signaling that are associated with Aβ-induced oxidative stress. Notably, female mice also showed downregulation of newly-synthesized ribosomal proteins. Furthermore, male mice showed an increase in newly-synthesized polypeptides involved in FcγR-mediated phagocytosis, while females showed an increase in newly-synthesized polypeptides responsible for actin organization associated with microglial activation. Next, we show that ABX-treatment resulted in substantial remodeling of the epigenetic landscape, leading to a metabolic shift that accommodates the increased bioenergetic and biosynthetic demands associated with microglial polarization in a sex-specific manner. While microglia in ABX-treated male mice exhibited a metabolic shift towards a neuroprotective phenotype that promotes Aβ clearance, microglia in ABX-treated female mice exhibited loss of energy homeostasis due to persistent mitochondrial dysfunction and impaired lysosomal clearance that was associated with inflammatory phenotypes.
Conclusions:
Our studies provide the first snapshot of the translational state of microglial/macrophage cells in a mouse model of Aβ amyloidosis that was subject to ABX treatment. ABX-mediated changes resulted in metabolic reprogramming of microglial phenotypes to modulate immune responses and amyloid clearance in a sex-specific manner. This microglial plasticity to support neuro-energetic homeostasis for its function based on sex paves the path for therapeutic modulation of immunometabolism for neurodegeneration.
Insights
Antibiotic treatment alters microglial function in a sex-specific manner, impacting Alzheimer's disease pathology. This study reveals sex-specific metabolic reprogramming in microglia, offering new therapeutic avenues for neurodegeneration.
Area of Science:
- Neuroimmunology
- Microbiology
- Neurodegeneration
- Alzheimer's Disease Research
Background:
- Microglia, the brain's immune cells, change phenotypes during pathological processes to maintain homeostasis.
- Previous studies showed antibiotic-induced gut microbiome changes in APPPS1-21 mice attenuated amyloidosis, particularly in males.
- The molecular mechanisms driving microglial phenotypic shifts in response to gut microbiome alterations remain largely unknown.
Purpose of the Study:
- To investigate the translational state of microglial/macrophage ribosomes during phenotypic transitions.
- To explore sex-specific molecular events underlying microglial responses to gut microbiome perturbations in a mouse model of Alzheimer's disease.
- To identify newly synthesized proteins in microglia/macrophages following antibiotic treatment.
Main Methods:
- Generation of APPPS1-21-CD11br reporter mice.
- Antibiotic (ABX) or vehicle treatment in male and female mice.
- Immunoprecipitation of microglial/macrophage polysomes, followed by liquid chromatography-tandem mass spectrometry and label-free quantification.
Main Results:
- ABX treatment decreased Aβ levels in male APPPS1-21 mice, with no significant effect in females.
- Identified sex-specific changes in newly synthesized polypeptides related to mitochondrial function, calcium signaling, FcγR-mediated phagocytosis (males), and actin organization (females).
- ABX treatment induced sex-specific epigenetic and metabolic reprogramming in microglia, promoting a neuroprotective phenotype in males and causing energy imbalance in females.
Conclusions:
- This study provides the first translational profile of microglia/macrophages in an ABX-treated mouse model of Aβ amyloidosis.
- ABX treatment reprograms microglial immunometabolism in a sex-specific manner, influencing immune responses and amyloid clearance.
- Microglial plasticity in supporting neuro-energetic homeostasis is sex-dependent, highlighting potential for immunometabolism-based therapies in neurodegeneration.
