Heterogeneity and mitochondrial vulnerability configurate the divergent immunoreactivity of human induced
Kousuke Yonemoto1, Fumihiko Fujii1, Ryoji Taira1
1Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Abstract:
Microglia play versatile roles in progression of and protection against neuroinflammatory diseases. Little is known, however, about the mechanisms underlying the diverse reactivity of microglia to inflammatory conditions. We investigated how human induced microglia-like (iMG) cells respond to innate immune ligands. Quantitative PCR showed that poly-I:C and lipopolysaccharide (LPS) activated the expression of IL1B and TNF. Immunoreactivity of iMG did not differ between controls (n = 11) and patients with neuroinflammatory diseases (n = 24). Flow cytometry revealed that CD14high cells expressed interleukin (IL) -1β after LPS treatment. Immunoblotting showed that poly-I:C and LPS differentially activated inflammatory pathways but commonly induced mitochondrial instability and the expression of pyruvate kinase isoform M2 (PKM2). Furthermore, a potent stimulator of PKM2 (DASA-58) alleviated IL-1β production after LPS treatment. These data indicate that heterogeneous cell populations and mitochondrial stability underlie the divergent immunoreactivity of human iMG in environments.
Insights
Human microglia-like cells show varied responses to inflammation, influenced by cell populations and mitochondrial stability. Targeting pyruvate kinase M2 (PKM2) may modulate these inflammatory pathways in neuroinflammatory diseases.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Microglia are crucial in neuroinflammatory diseases, but mechanisms of their diverse reactivity remain unclear.
- Understanding microglial responses to inflammatory stimuli is vital for developing targeted therapies.
Purpose of the Study:
- To investigate the response mechanisms of human induced microglia-like (iMG) cells to innate immune ligands.
- To explore the role of mitochondrial stability and pyruvate kinase M2 (PKM2) in microglial inflammatory responses.
Main Methods:
- Quantitative PCR, flow cytometry, and immunoblotting were used to analyze iMG responses to poly-I:C and lipopolysaccharide (LPS).
- Human iMG cells from controls and neuroinflammatory disease patients were compared.
- The effect of a PKM2 stimulator (DASA-58) on IL-1β production was assessed.
Main Results:
- Poly-I:C and LPS induced IL1B and TNF expression in iMG cells.
- No significant difference in iMG immunoreactivity was observed between controls and patients.
- LPS treatment led to IL-1β expression in CD14high cells.
- Both ligands induced mitochondrial instability and PKM2 expression, with differential inflammatory pathway activation.
- DASA-58 mitigated IL-1β production following LPS stimulation.
Conclusions:
- Heterogeneous cell populations and mitochondrial stability contribute to divergent human iMG immunoreactivity.
- PKM2 activation may represent a therapeutic target for modulating microglial inflammatory responses in neuroinflammatory conditions.
