Cerebral complement C1q activation in chronic Toxoplasma infection

Area of Science:

• Neuroscience
• Immunology
• Parasitology

Background:

• Toxoplasma gondii (T. gondii) infection causes brain and behavioral changes.
• Complement factor C1q (C1q) is involved in immune responses and synaptic pruning in the brain.
• Both T. gondii and C1q are linked to complex brain disorders like schizophrenia.

Purpose of the Study:

• To investigate the link between T. gondii infection and C1q activation in the brain.
• To determine if T. gondii cysts trigger C1q upregulation in a rodent model.

Main Methods:

• A rodent model of chronic T. gondii infection was used.
• Cortical C1q expression was measured at RNA and protein levels.
• C1q protein localization was examined in infected brain tissue.

Main Results:

• Cortical C1q was significantly upregulated in T. gondii-infected mice compared to uninfected controls.
• C1q protein was found in the cytoplasm, near astrocytes and degenerating cysts, and along cellular processes.
• High cyst burden correlated with increased C1q expression.

Conclusions:

• Latent T. gondii infection leads to increased C1q in the brain.
• C1q activation may play a role in clearing T. gondii from the central nervous system.
• This process might impact neuronal connectivity and synaptic function.