The solute carriers ZIP8 and ZIP14 regulate manganese accumulation in brain microvascular endothelial cells and...

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Manganese is vital for neuronal function but toxic in excess.
• Tight regulation of manganese at the blood-brain barrier (BBB) is essential for brain health.
• The specific molecular mechanisms for manganese transport within BBB endothelial cells remain unclear.

Purpose of the Study:

• To investigate the molecular pathways responsible for manganese (Mn²⁺) transport in brain microvascular endothelial cells (BMVECs).
• To identify the transporters involved in Mn²⁺ uptake across the BBB.
• To elucidate the role of these transporters in manganese homeostasis.

Main Methods:

• Utilized siRNA-mediated knockdown to assess the role of ZIP8 and ZIP14 in Mn²⁺ uptake.
• Performed kinetic analyses to determine the biochemical characteristics of manganese uptake.
• Employed membrane protein biotinylation to confirm transporter localization at the cell surface.

Main Results:

• ZIP8 and ZIP14 were identified as the primary transporters for Mn²⁺ uptake in BMVECs.
• Neither DMT1 nor endocytosis played a significant role in Mn²⁺ uptake.
• Manganese uptake kinetics were influenced by pH, bicarbonate, and lipopolysaccharide, consistent with ZIP8/ZIP14 activity.
• ZIP8 and ZIP14 facilitate bidirectional Mn²⁺ flux across both the apical and basal membranes of BMVECs.

Conclusions:

• ZIP8 and ZIP14 are critical for mediating manganese transport across the BBB.
• These transporters enable bidirectional Mn²⁺ flux, playing a key role in brain manganese homeostasis.
• BMVECs are central players in controlling manganese levels within the brain.