Helminthic larval stage induces cellular apoptosis via caspase 9-mediated mitochondrial dysfunction

Area of Science:

• Neuroimmunology
• Parasitology
• Molecular Biology

Background:

• Neurocysticercosis (NCC) pathogenesis, particularly brain inflammation and seizures, remains poorly understood.
• The viability of Taenia solium cysts influences disease severity, with degenerating cysts driving inflammation.
• Previous work indicated that fluid from degenerating cysts induces inflammation in immune cells.

Purpose of the Study:

• To elucidate the apoptotic signaling pathways involved in host-parasite interactions in NCC.
• To determine the role of these pathways in symptomatic disease development in NCC patients.

Main Methods:

• Exposure of immune cells (human, porcine, murine) to T. solium cyst vesicular fluid (CVF).
• Analysis of apoptosis signaling via caspase assays and mitochondrial probes.
• Identification of apoptosis-inducing molecules using mass spectrometry.
• Measurement of caspase activity and soluble mediators in patient sera.

Main Results:

• CVF induced dose-dependent apoptosis and caspase 3/9 activity in immune cells, primarily via the intrinsic pathway.
• Mitochondrial dysfunction and decreased Bid/Bcl2 transcription were observed.
• Symptomatic NCC patients showed elevated FasL levels correlating with caspase activity.

Conclusions:

• Caspase 9-mediated apoptosis is a key mechanism in helminth-induced brain inflammation in NCC.
• FasL signaling is implicated in the progression of symptomatic NCC.
• Findings provide insights into NCC immunopathogenesis and potential therapeutic targets.