RIPK3 interactions with MLKL and CaMKII mediate oligodendrocytes death in the developing brain

Area of Science:

• Neuroscience
• Cell Biology
• Developmental Biology

Background:

• Oligodendrocyte progenitor cell (OPC) death contributes to white matter injury (WMI) in developing brains.
• Receptor-interacting proteins (RIPs) are implicated in necroptosis, a form of programmed cell death, in developing neurons.
• The role of RIP-mediated necroptosis in OPCs death remained unclear.

Purpose of the Study:

• To investigate the mechanisms of RIP-mediated death in oligodendrocytes (OLs) within the developing brain.
• To determine the involvement of RIPK3, MLKL, and CaMKIIδ in OLs death and myelin development following hypoxia-ischemia (HI).

Main Methods:

• In vitro induction of oligodendrocyte necroptosis using oxygen-glucose deprivation plus zVAD (OGD/zVAD).
• Western blotting, immunofluorescence, and immunoprecipitation to analyze RIPK1, RIPK3, MLKL, and CaMKIIδ expression and interactions.
• Inhibition of RIPK3-MLKL or RIPK3-CaMKIIδ interactions using siRNA or specific inhibitors.
• In vivo induction of brain damage in neonatal rats via HI to assess myelin development.

Main Results:

• OGD/zVAD upregulated RIPK3 expression and its interaction with MLKL and CaMKIIδ.
• Inhibition of RIPK3-MLKL or RIPK3-CaMKIIδ interactions attenuated OGD/zVAD-induced OLs death.
• MLKL translocation to the OLs membrane and CaMKIIδ phosphorylation were key protective mechanisms.
• Inhibition of RIPK3-MLKL or RIPK3-CaMKIIδ interactions improved myelin development in HI-induced neonatal rat brain injury.

Conclusions:

• RIPK3 plays a critical role in protecting against OLs death and abnormal myelin development.
• RIPK3 mediates these protective effects through its interactions with MLKL and CaMKIIδ.
• RIPK3 represents a potential therapeutic target for neonatal white matter injury.