Bulk RNA-seq Analysis

LCM-based Transcriptomic Profiling of Epileptogenesis

Study Design

Experimental Approach

Laser capture microdissection (LCM) combined with bulk RNA-seq was used to profile transcriptional changes during the critical epileptogenic window in the GAERS model.

  • Comparison: Ga30 (P30, seizure-onset) vs Ga15 (P15, pre-seizure)
  • Sample Size: 5 Ga30 samples, 2 Ga15 samples
  • Library Prep: Takara SMARTer Stranded Total RNA-Seq Kit v3
  • Sequencing: Illumina platform
  • Analysis: DESeq2 differential expression

Key Findings

593 Differentially Expressed Genes

  • 560 upregulated (94.4%)
  • 33 downregulated (5.6%)
  • Thresholds: padj < 0.1, |log2FC| > 0.5

Biological Significance: The predominant upregulation indicates active neuronal maturation and circuit development during the transition from pre-seizure to seizure-prone state.

Summary Statistics

593 Significant DEGs
560 Upregulated
33 Downregulated
3,700 Genes Tested

Volcano Plot

Differential Expression Overview (Ga30 vs Ga15)

Interpretation: Each point represents a gene. Red points are significantly upregulated, blue points are significantly downregulated. Distance from center indicates magnitude of change and statistical significance.

Top Differentially Expressed Genes

Top 20 Upregulated Genes

Top 20 Downregulated Genes

Top 10 Most Significant Genes

Rank Gene Symbol Gene Name Log2FC Adj. P-value Regulation

GO Enrichment Analysis

Top Enriched Biological Processes

Loading enrichment data...

Key Enriched Pathways

Synaptic Organization:

  • Cell junction maintenance
  • Postsynaptic density organization
  • Regulation of synaptic plasticity

Calcium & Ion Channels:

  • Calcium homeostasis
  • IP3 signaling
  • Voltage-gated ion channels

Biological Interpretation

Major Findings

  1. Predominant Upregulation (94.4%): The overwhelming majority of DEGs show increased expression at P30, indicating active transcriptional programs associated with neuronal maturation and circuit development during the epileptogenic window.
  2. Synaptic Plasticity & Organization: Strong enrichment in postsynaptic density organization, synaptic plasticity, and maintenance of synaptic structures reflects critical circuit refinement occurring as GAERS rats transition to seizure-prone state.
  3. Calcium Signaling Dysregulation: Enrichment in calcium homeostasis and ion channel genes, including T-type calcium channels (Cacna1g, Cacna1h), aligns with known mechanisms of absence seizure generation in thalamocortical circuits.
  4. Glutamatergic Transmission: Upregulation of NMDA receptor components and glutamatergic signaling genes consistent with thalamocortical hyperexcitability in GAERS.

Clinical Relevance

These transcriptional changes identify potential therapeutic targets for preventing or modulating absence seizure development. The prominent synaptic and ion channel dysregulation provides molecular evidence for circuit-level dysfunction underlying epileptogenesis.

Download Data

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