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Three-dimensional Confocal Analysis of Microglia/macrophage Markers of Polarization in Experimental Brain Injury
Published on: September 4, 2013
M1 Microglia Induced Neuronal Injury on Ischemic Stroke via Mitochondrial Crosstalk between Microglia and Neurons
Wei Liu1, Zitong Qi1, Wanmeng Li1
1School of Pharmacy, Jinzhou Medical University, Jinzhou 121000, China.
Abstract:
Among the middle-aged and senile populations, ischemic stroke (IS) is a frequently occurring acute condition of the cerebrovascular system. Traditionally, it is recognized that when stroke occurs, microglia are activated into M1 phenotype and release cytotoxic cytokines, reactive oxygen species, proteases, and other factors, thus exacerbating the injury by further destroying or killing nearby neurons. In the latest research, the crucial role of the intercellular mitochondrial crosstalk on the stroke management has been demonstrated. Therefore, we tried to clarify mitochondrial crosstalk between microglia and neurons, and evaluated M1 microglial mitochondria-mediated neurological performance in transient middle cerebral artery occlusion (tMCAO) rats. We found that when microglia was activated into the proinflammatory M1 type after stroke, mitochondrial fission process was accelerated, and damaged mitochondria were released, further transferred to neurons and fused with neuronal mitochondria. As a result, the function of neuronal mitochondria was damaged by decreasing adenosine triphosphate (ATP), mitochondria membrane potential, and increasing excessive reactive oxygen species (ROS), thus inducing mitochondria-mediated neuronal death and finally aggravating ischemia injury. Taken together, it provides a novel neuroglial crosstalk mechanism at the mitochondrial level.
Insights
Stroke triggers M1 microglia to release damaged mitochondria, harming neurons and worsening brain injury. This study reveals a novel intercellular mitochondrial crosstalk mechanism in ischemic stroke.
Area of Science:
- Neuroscience
- Cell Biology
- Pathology
Background:
- Ischemic stroke (IS) is a major cause of death and disability, particularly in older adults.
- Activated microglia (M1 phenotype) traditionally contribute to neuronal damage post-stroke via cytotoxic factors.
- Emerging evidence highlights the role of intercellular mitochondrial transfer in disease pathology.
Purpose of the Study:
- To investigate mitochondrial crosstalk between microglia and neurons following ischemic stroke.
- To evaluate the impact of M1 microglial mitochondria on neurological function in a rat stroke model.
Main Methods:
- Transient middle cerebral artery occlusion (tMCAO) model in rats to induce ischemic stroke.
- Analysis of microglial activation, mitochondrial dynamics (fission/fusion), and transfer.
- Assessment of neuronal mitochondrial function (ATP levels, membrane potential, ROS production).
Main Results:
- Stroke induced M1 microglial activation and accelerated mitochondrial fission.
- Damaged mitochondria were released from activated microglia and transferred to neurons.
- Neuronal mitochondrial dysfunction, characterized by decreased ATP and membrane potential, and increased ROS, was observed.
- This mitochondrial transfer aggravated ischemia-induced neuronal death and neurological deficits.
Conclusions:
- M1 microglia transfer damaged mitochondria to neurons, impairing neuronal mitochondrial function.
- This novel intercellular mitochondrial crosstalk mechanism contributes significantly to stroke-induced brain injury.
- Targeting mitochondrial crosstalk may offer a new therapeutic strategy for ischemic stroke.
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