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Characterization of Immune Cell-derived Extracellular Vesicles and Studying Functional Impact on Cell Environment
Published on: June 2, 2020
Exosomes from polarized Microglia: Proteomic insights into potential mechanisms affecting intracerebral hemorrhage
Yinan Zhou1, Ying Zhang2, Dongchen Xu1
1Zhejiang Provincial Key Laboratory of Aging and Neurological Disorder Research, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China; Department of Neurosurgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China.
Abstract:
Intracerebral hemorrhage (ICH) is a devastating form of stroke associated with significant morbidity and mortality. Microglia are intracranial innate immune cell that play critical roles in Intracerebral hemorrhage through direct or indirect means. Vesicle transport is a fundamental mechanism of intercellular communication. Recent studies have identified microglia in specific polarized states correlate with pathogenesis, material and signal transmission in ICH through derived extracellular vesicles. Diverse polarization states trigger distinct functions, however, the exosome proteomes across these states remain poorly characterized. Here, we hypothesized that microglia exosomal profiles vary with polarization states, impacting their functional repertoire and influencing outcomes in cerebral hemorrhage. In vitro model of cerebral hemorrhage, administration of 20 μg/ml LPS-induced M1 microglia derived exosomes (M1-Exo) with HT22 enhanced hemin-induced neuronal death, while IL-4-induced M2 microglia derived exosomes (M2-Exo) significantly reduced hemin-induced cell apoptosis and inflammation. Then we identified novel state-specific proteomic profiles of microglia-derived exosomes under these polarization conditions through label-free quantitative mass spectrometry (LFQ-MS). Analysis of protein content identified several exosomal signature proteins and hundreds of differentially expressed proteins across polarization states. Specifically, proteins including UMOD, NLRP3, ACOD1, IL1RN, heme oxygenase 1 (HMOX1), CCL4, and TNFRSF1B in M1-Exo were enriched in inflammatory pathways, while those in M2-Exo exhibited enrichment in autophagy, ubiquitination, and mitochondrial respiration. The analysis of those diverse exosomal proteins suggested unique proteomic profiles and possible intracellular signal transmission and regulation mechanisms. Together, these findings offer new insights and resources for studying microglia-derived exosome and pave the way for the development of novel therapeutic strategies targeting microglial exosome-mediated pathways.
Insights
Microglia exosomes from different polarization states show distinct protein profiles, influencing outcomes in intracerebral hemorrhage (ICH). M1 exosomes worsen neuronal death, while M2 exosomes reduce apoptosis and inflammation, offering therapeutic targets.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Intracerebral hemorrhage (ICH) is a severe stroke type with high mortality.
- Microglia, the brain's innate immune cells, are crucial in ICH pathogenesis.
- Microglia communicate via extracellular vesicles, particularly exosomes, but their proteomes in different states are unknown.
Purpose of the Study:
- To investigate how microglia exosome proteomes differ based on polarization states (M1 vs. M2).
- To determine the functional impact of these distinct exosomes on neuronal survival and inflammation in an ICH model.
- To identify novel exosomal proteins associated with specific microglia functions in ICH.
Main Methods:
- Established an in vitro model of cerebral hemorrhage.
- Utilized LPS to induce M1 microglia and IL-4 for M2 microglia.
- Characterized microglia-derived exosomes (M1-Exo, M2-Exo) using label-free quantitative mass spectrometry (LFQ-MS).
- Assessed the effects of M1-Exo and M2-Exo on hemin-induced neuronal death and inflammation.
Main Results:
- M1-Exo exacerbated hemin-induced neuronal death and inflammation.
- M2-Exo significantly reduced hemin-induced neuronal apoptosis and inflammation.
- LFQ-MS identified unique proteomic profiles for M1-Exo and M2-Exo.
- M1-Exo proteins were enriched in inflammatory pathways (e.g., NLRP3, CCL4).
- M2-Exo proteins were enriched in autophagy, ubiquitination, and mitochondrial respiration pathways.
Conclusions:
- Microglia exosome proteomes are distinct and state-specific.
- These proteomic differences mediate functional outcomes in cerebral hemorrhage.
- Findings provide insights into exosome-mediated intercellular communication in ICH.
- Identified potential therapeutic targets for modulating microglial exosome activity in ICH.
