[The Peptide Drug ACTH(4-7)PGP (Semax) Suppresses mRNA Transcripts Encoding Proinflammatory Mediators Induced by...

Due to its nootropic, neuroprotective, and immunomodulatory effects, the peptide Semax is utilized in the treatment of ischemic stroke. Our earlier RNA-Seq analysis of the transcriptome in an ischemic model of transient occlusion of the middle cerebral artery showed an increase in the mRNA levels of many proinflammatory genes, and the suppression of their induction by Semax. However, for many relevant genes, including Il1a, Il1b, Il6 and Tnfa, the levels of their expression were too low for detailed quantitative evaluation. Here we utilize qRT-PCR to analyze the effects of the Semax peptide on the expression of weakly expressed mRNAs encoding several proinflammatory mediators, and show that exposure to Semax leads to a statistically significant decrease in the Il1a, Il1b, Il6, Ccl3, and Cxcl2 mRNAs, which compensates for the increase in the transcription of these genes induced by ischemia-reperfusion. We conclude that the observed protective effect of Semax in the model of stroke may be due to its anti-inflammatory effects. We also discuss the limitations of the RNA-Seq when applied to quantifying less abundant transcripts as compared to the real-time RT-PCR method.