Pericystic brain transcriptomics reveals molecular signatures of immune activation and neurovascular remodelling in viable and post-treatment porcine neurocysticercosis

Technical Summary: Pericystic Brain Transcriptomics in Porcine Neurocysticercosis

Problem Statement
Neurocysticercosis (NCC), caused by the larval stage of Taenia solium, is a primary etiology of acquired epilepsy in endemic regions. A critical clinical paradox exists within the disease progression: viable cysticerci often persist asymptomatically for extended periods, whereas their spontaneous or drug-induced degradation precipitates severe perilesional inflammation and neurological symptoms. While the histopathological distinctions between these lesion states are well-documented, the underlying host transcriptional programs driving parasite persistence versus treatment-induced lesion disruption remain poorly characterized. Specifically, there is a lack of molecular data defining the host response in the pericystic brain tissue during both viable infection and the early post-treatment phase.

Methodology
To address this knowledge gap, the authors conducted the first bulk RNA sequencing (RNA-seq) analysis of pericystic brain tissue. The study utilized a physiologically relevant porcine model of NCC to ensure biological fidelity. The experimental design compared three distinct groups:

1. Uninfected controls (n = 3).
2. Infected, untreated pigs harboring intact, viable cysts (n = 6).
3. Antiparasitic-treated pigs with confirmed cyst disruption (n = 3).

This comparative framework allowed for the identification of distinct transcriptional signatures associated with the transition from viable persistence to post-treatment lesion disruption.

Key Results
The transcriptomic analysis revealed distinct molecular profiles for each disease state:

• Viable Infection State: This condition was associated with broad transcriptional alterations, comprising 461 upregulated and 175 downregulated genes. The molecular signature was characterized by local immune activation coupled with the suppression of molecular pathways related to blood-brain barrier (BBB) remodelling, vascular function, and neuronal signalling.
• Post-Treatment State: Following antiparasitic treatment and confirmed BBB disruption, the transcriptional response was smaller in magnitude but directionally distinct, involving 160 upregulated and 57 downregulated genes. This state was marked by robust inflammatory signalling and a significant upregulation of genes associated with endothelial activation, vascular regulation, and BBB-associated remodelling.

A central finding is that while immune engagement is a shared feature across both lesion states, the transcriptional axis governing BBB-associated processes shifts substantially following treatment.

Significance and Claims
The paper positions these findings as an exploratory transcriptomic framework rather than a definitive mechanistic conclusion. The authors claim that this study provides the first molecular characterization of pericystic brain tissue in a porcine NCC model, offering a foundational resource for understanding:

• The mechanisms of parasite persistence.
• The nature of treatment-induced neuroinflammation.
• The dynamics of neurovascular remodelling in NCC.

The study highlights specific candidate pathways and genes that warrant future mechanistic investigation. The authors maintain a modest scope, framing the work as a necessary step toward elucidating the complex host-parasite interactions that dictate clinical outcomes in neurocysticercosis, without proposing immediate clinical applications or unverified future experimental directions.