Peritoneal macrophages express the serotonin transporter

Area of Science:

• Immunology
• Neuroscience
• Molecular Biology

Background:

• Macrophages are known to internalize serotonin.
• However, the specific molecular transporter responsible for this uptake in macrophages has remained unidentified.
• Understanding serotonin transport in macrophages is crucial for comprehending neuro-immune interactions.

Purpose of the Study:

• To identify and characterize the serotonin transporter (SERT) in mouse peritoneal macrophages.
• To investigate the functional expression and regulation of SERT in macrophages.

Main Methods:

• Reverse transcription-polymerase chain reaction (RT-PCR) was employed to detect SERT mRNA.
• Sequencing was used to confirm the identity of the amplified SERT mRNA.
• Western blotting was performed to detect SERT protein expression.
• Functional uptake assays using radiolabeled serotonin were conducted.

Main Results:

• SERT mRNA was successfully detected in recruited mouse peritoneal macrophages.
• Sequencing confirmed the presence of mouse SERT mRNA.
• SERT protein was also detected via Western blotting.
• Macrophage activation with lipopolysaccharide did not alter SERT mRNA or protein levels.
• Macrophages exhibited specific, sodium-dependent uptake of serotonin.
• This uptake was potently inhibited by fluoxetine and desipramine, indicating functional SERT activity.

Conclusions:

• The serotonin transporter (SERT) is expressed at both mRNA and protein levels in mouse peritoneal macrophages.
• Macrophages possess a functional SERT that mediates serotonin uptake.
• SERT expression in macrophages is not modulated by lipopolysaccharide activation.
• This study identifies SERT as a key mediator of serotonin handling in macrophages, with implications for neuroinflammation and immune cell function.