MeCP2 deficiency enhances glutamate release through NF-κB signaling in myeloid derived cells

Area of Science:

• Neuroimmunology
• Molecular Biology
• Cellular Signaling

Background:

• Glutamate is a key neurotransmitter, and its dysregulation is linked to various neurological disorders.
• Microglia and peripheral blood mononuclear cells play critical roles in neuroinflammation and immune responses.
• Methyl CpG-binding protein 2 (MeCP2) is crucial for neuronal development and function, with its deficiency associated with severe neurological conditions.

Purpose of the Study:

• To investigate the signaling pathway regulating glutamate release in myeloid lineage cells.
• To explore the role of the nuclear factor-kappa B (NF-κB) pathway in glutamate release.
• To determine the relationship between MeCP2 deficiency and NF-κB activation in glutamate release.

Main Methods:

• Quantification of glutaminase mRNA levels in microglia and human peripheral blood mononuclear cells (PBMCs).
• Measurement of glutamate release in cell cultures stimulated with lipopolysaccharide (LPS) and Pam3CSK.
• Inhibition of the NF-κB pathway using specific inhibitors and assessment of MeCP2 levels and NF-κB reporter activity.

Main Results:

• Lipopolysaccharide (LPS) and Pam3CSK treatment increased glutamate release in neonatal mouse microglia, which was reduced by NF-κB inhibitors.
• MeCP2 deficiency in human PBMCs and THP1 monocyte cell lines led to elevated glutaminase mRNA and glutamate release, blocked by NF-κB inhibitors.
• An inverse correlation was observed between MeCP2 levels and NF-κB reporter activity in THP1 cells.

Conclusions:

• The NF-κB signaling pathway is critically involved in regulating glutamate release in myeloid lineage cells.
• NF-κB activation contributes to increased glutamate release in MeCP2-deficient cells.
• These findings highlight a novel mechanism linking MeCP2 deficiency, NF-κB signaling, and glutamate dysregulation in the myeloid system.