Age-Related Changes in Neuron-Microglia Interaction Mediated by Fractalkine Under Inflammatory Conditions.

Area of Science:

• Neuroscience
• Immunology
• Aging Research

Background:

• Aging is associated with increased microglial activation and neuroinflammation.
• Neuron-microglia crosstalk, mediated by fractalkine (CX3CL1) and its receptor CX3CR1, plays a crucial role in regulating microglial function.
• Dysregulation of this pathway may contribute to age-related neurological decline.

Purpose of the Study:

• To investigate age-dependent changes in CX3CL1 and CX3CR1 expression and CX3CL1 proteoforms.
• To assess the impact of inflammation on these age-related alterations.
• To understand the role of TGFβ in modulating these pathways during aging and inflammation.

Main Methods:

• Analysis of CX3CL1, CX3CR1, and TGFβ mRNA levels using RT-qPCR in mice of different ages (3 to >20 months).
• Quantification of CX3CL1 proteoforms via Western blot.
• Utilized wild-type (WT) mice and an inflammatory model (SRA-/-) subjected to LPS or TGFβ treatment.

Main Results:

• CX3CL1 mRNA decreased in aged mice (>20 months), while soluble CX3CL1 increased in adult mice.
• CX3CR1 mRNA showed a progressive increase with age, peaking in aged mice.
• TGFβ levels were highest in adult mice and decreased in aged mice; inflammation exacerbated CX3CL1 and CX3CR1 mRNA, effects partially mitigated by TGFβ.

Conclusions:

• Aging significantly alters CX3CL1 and TGFβ expression, with peak levels observed in adult mice.
• These age-related changes in neuron-microglia signaling molecules may represent early events initiating neurodegenerative disease.
• Inflammation further modulates these pathways, highlighting their complex role in aging and brain health.