The peptide semax affects the expression of genes related to the immune and vascular systems in rat brain focal ischemia: genome-wide transcriptional analysis

Understanding the full scope of a drug's effects at the genetic level provides the deepest insights into how it works. This genome-wide transcriptional analysis by Medvedeva, Dmitrieva, Povarova, and colleagues, published in BMC Genomics, mapped Semax's complete genetic fingerprint during brain ischemia.

The researchers performed whole-genome transcriptional profiling of brain tissue from rats experiencing focal ischemia, comparing animals treated with Semax to untreated controls at 3 and 24 hours after the ischemic event. This comprehensive approach captured the full spectrum of Semax's effects on gene expression.

The results revealed a striking pattern: Semax predominantly enhanced genes associated with the immune system. At 24 hours post-stroke, over 50% of the genes altered by Semax treatment related to immune function, including those encoding immunoglobulins and chemokines. Additionally, Semax significantly modified expression of genes governing vascular development and endothelial tissue migration, suggesting it actively promotes the restoration of blood supply to damaged brain regions.

This genome-wide study provides the most comprehensive picture yet of how Semax protects the brain. The dual immunomodulatory and vascular mechanism explains the peptide's remarkable effectiveness in stroke models — it simultaneously calms harmful inflammation while promoting the blood vessel growth needed to restore circulation. This broad genomic impact positions Semax as one of the most mechanistically well-understood neuroprotective peptides available.