Differential Regional Responses in Soluble Monomeric Alpha Synuclein Abundance Following Traumatic Brain Injury

Area of Science:

• Neuroscience
• Neurobiology
• Cellular Biology

Background:

• Alpha synuclein (α-synuclein) is a neuronal protein primarily located in presynaptic terminals.
• While α-synuclein aggregates are studied in neurodegeneration, monomeric α-synuclein's physiological role and changes post-injury are less understood.
• Evidence suggests α-synuclein plays a role in neurotransmission.

Purpose of the Study:

• To investigate chronic changes in regional monomeric α-synuclein abundance after traumatic brain injury (TBI).
• To assess the impact of TBI on α-synuclein levels in the cortex, hippocampus, and striatum over time.

Main Methods:

• Adult rats underwent controlled cortical impact (CCI) TBI.
• α-synuclein levels were measured using Western blot and immunohistochemistry at various time points (6 hours to 8 weeks post-injury).
• Levels were compared between injured (ipsilateral) and sham animals.

Main Results:

• Monomeric α-synuclein protein levels were significantly decreased in the ipsilateral hippocampus at multiple time points post-TBI.
• Reduced α-synuclein was also observed in the ipsilateral cortex and striatum at specific early time points.
• Immunohistochemistry showed lower α-synuclein and synaptophysin staining in the hippocampus 1 week post-TBI, without aggregate formation.

Conclusions:

• Monomeric α-synuclein abundance is chronically reduced in the hippocampus following TBI.
• This sustained deficit in monomeric α-synuclein may contribute to impaired neurotransmission observed long-term after TBI.