Related Experiment Video
Updated: Jun 19, 2025
Primary Microglia Isolation from Mixed Glial Cell Cultures of Neonatal Rat Brain Tissue
Published on: August 15, 2012
Microglia mitochondrial complex I deficiency during development induces glial dysfunction and early lethality
Bella Mora-Romero1,2,3, Nicolas Capelo-Carrasco1,3,4, Juan J Pérez-Moreno5,6,7
1Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.
Abstract:
Primary mitochondrial diseases (PMDs) are associated with pediatric neurological disorders and are traditionally related to oxidative phosphorylation system (OXPHOS) defects in neurons. Interestingly, both PMD mouse models and patients with PMD show gliosis, and pharmacological depletion of microglia, the innate immune cells of the brain, ameliorates multiple symptoms in a mouse model. Given that microglia activation correlates with the expression of OXPHOS genes, we studied whether OXPHOS deficits in microglia may contribute to PMDs. We first observed that the metabolic rewiring associated with microglia stimulation in vitro (via IL-33 or TAU treatment) was partially changed by complex I (CI) inhibition (via rotenone treatment). In vivo, we generated a mouse model deficient for CI activity in microglia (MGcCI). MGcCI microglia showed metabolic rewiring and gradual transcriptional activation, which led to hypertrophy and dysfunction in juvenile (1-month-old) and adult (3-month-old) stages, respectively. MGcCI mice presented widespread reactive astrocytes, a decrease of synaptic markers accompanied by an increased number of parvalbumin neurons, a behavioral deficit characterized by prolonged periods of immobility, loss of weight and premature death that was partially rescued by pharmacologic depletion of microglia. Our data demonstrate that microglia development depends on mitochondrial CI and suggest a direct microglial contribution to PMDs.
Insights
Mitochondrial defects in microglia contribute to primary mitochondrial diseases (PMDs). Impaired Complex I in these brain immune cells causes dysfunction and neurological symptoms, suggesting a novel therapeutic target for PMDs.
Area of Science:
- Neuroscience
- Immunology
- Mitochondrial Biology
Background:
- Primary mitochondrial diseases (PMDs) often involve neurological disorders linked to oxidative phosphorylation (OXPHOS) defects.
- Gliosis and symptom amelioration via microglial depletion in PMD models suggest a role for these brain immune cells.
Purpose of the Study:
- To investigate if OXPHOS deficits specifically in microglia contribute to the pathology of PMDs.
- To understand the role of mitochondrial Complex I (CI) in microglial function and its impact on neurological health.
Main Methods:
- In vitro studies assessing microglial metabolic response to stimulation and CI inhibition (rotenone).
- Generation and analysis of a mouse model with CI deficiency specifically in microglia (MGcCI).
- Assessment of microglial morphology, gene expression, brain pathology (gliosis, synaptic markers), and behavioral deficits in MGcCI mice.
Main Results:
- Microglial stimulation showed altered metabolic rewiring with CI inhibition in vitro.
- MGcCI mice exhibited microglial metabolic and transcriptional changes, leading to hypertrophy and dysfunction.
- MGcCI mice displayed reactive astrocytes, synaptic loss, altered neuronal populations, behavioral deficits, and premature death, partially rescued by microglial depletion.
Conclusions:
- Microglial development and function are dependent on mitochondrial Complex I activity.
- OXPHOS deficits in microglia represent a direct contribution to primary mitochondrial diseases, offering new therapeutic avenues.
