Knockout of Spp1/OPN Aggravates Seizure Susceptibility via Blood-Brain Barrier Dysfunction in a Pilocarpine-Induced Murine Model
Abstract number :
1.004
Submission category :
1. Basic Mechanisms / 1A. Epileptogenesis of acquired epilepsies
Year :
2025
Submission ID :
701
Source :
www.aesnet.org
Presentation date :
12/6/2025 12:00:00 AM
Published date :
Authors :
Presenting Author: Weifeng Peng, MD – Zhongshan Hospital Fudan University
Lan Liu, PhD – Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China
Chenming Lin, MSN – Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China
Zihan Hu, MD – Zhongshan Hospital Fudan University
Rationale: Emerging evidence suggests blood-brain barrier (BBB) dysfunction contributes to epileptogenesis. Osteopontin (OPN), abundantly expressed in BBB-associated endothelial cells, neurons, glia, and extracellular matrix, may exert neuroprotective effects. This study investigated how OPN deficiency modulates BBB integrity and neuroinflammation in epileptogenesis.
Methods: Utilizing Spp1/OPN-knockout (KO) and wild-type (WT) mice, seizure was induced via lithium-pilocarpine. Seizure severity, latency to the first attack, electroencephalographic (EEG) activity, and hippocampal pathology were assessed at 6h, 24h, 72h, and 7d post-status epilepticus (SE). BBB disruption was detected via albumin, occludin-5 immunofluorescence and Western blot. RNA transcriptomic sequencing was used to compare hippocampal gene signatures between WT and Spp1-KO groups. And neuroinflammation (microglial activation, cytokine profiling) were analyzed based on RNAseq results.
Results: Spp1/OPN-KO mice exhibited exacerbated seizure intensity (P< 0.01), shortened latency to first seizure (P< 0.05), and increased ictal discharges at 6h (P< 0.05, Figure 1). WT mice showed transient OPN upregulation peaking at 6h, 24h, and 72h, paralleling increased expression of albumin and occludin-5 in the hippocampus. Compared to WT mice, Spp1/OPN-KO mice showed greater neuronal loss and microgliosis across all timepoints of 6h, 24h, 72h, and 7d post-SE compared to WT mice, and significantly greater BBB disruptions were also observed at baseline and 7d post-SE in the hippocampi of Spp1/OPN-KO mice. RNA transcriptomics revealed suppressed innate immunity pathways but hyperactivated pro-inflammatory cascades (especially IL-23a, Figure 2) in the hippocampi at 7d post-SE of Spp1/OPN-KO mice compared to WT mice. Increased expression of co-localization of OPN, CD31, Itgax, and Iba-1 indicated that BBB leakage promoted activated microglia and increased IL-23a, which might mediated inflammation in the hippocampus, then promoting neuronal damage and epileptogenesis.
Conclusions: These findings demonstrate that Spp1/OPN deficiency exacerbates epileptogenesis through impairing BBB resilience and amplifying neuroinflammatory signaling. OPN emerges as a critical modulator of neuroimmune crosstalk, suggesting its therapeutic potential for targeting BBB-centric epilepsy pathogenesis.
Funding: Chunshen Pyramid Leading Talent Program, Minhang District, Shanghai, China
Basic Mechanisms