ACTH(4-7)PGP (Semax) and ACTH(6-9)PGP Normalize Gene Expression in Rat Striatum Post-Ischemic Stroke
Background
Ischemic stroke leads to significant neuronal damage, with current treatments often limited in their neuroprotective scope. Natural peptides like adrenocorticotropic hormone (ACTH) and its non-hormonal fragments, such as ACTH(4-7)PGP (Semax) and ACTH(6-9)PGP, offer potential as neuroprotective agents. These peptides have previously demonstrated beneficial effects on nervous system functions, including modulating gene expression in the frontal cortex after stroke. Understanding their precise molecular mechanisms across different brain regions with varying ischemic damage is crucial for developing targeted therapies.
Study Design
Researchers investigated the gene expression profiles in the striatum of rats 24 hours after a transient middle cerebral artery occlusion (tMCAO) model of ischemic stroke. The study utilized the same animals previously treated with ACTH(4-7)PGP (Semax) or ACTH(6-9)PGP peptides, from which frontal cortex samples were also acquired. Gene expression was analyzed using RNA-Seq to identify differentially expressed genes (DEGs) in the ischemic striatum compared to control conditions and to assess the peptides' impact on these profiles.
Results
Both ACTH(4-7)PGP (Semax) and ACTH(6-9)PGP peptides tended to normalize the expression profiles of hundreds of genes disrupted by ischemia in the rat striatum. The number of differentially expressed genes (DEGs) in the striatum was lower than previously observed in the frontal cortex. Notably, ACTH(6-9)PGP action led to an even more affected profile for 152 genes in the striatum, predominantly associated with inflammation. Conversely, approximately 100 genes showed overlapping regulation by both peptides across both the striatum and frontal cortex, primarily linked to neuroactive ligand-receptor interaction. This suggests distinct and shared molecular pathways are influenced by these peptides depending on the brain region and specific peptide.
Key Findings
- ACTH(4-7)PGP (Semax) and ACTH(6-9)PGP normalized hundreds of ischemia-disrupted genes in rat striatum.
- Fewer differentially expressed genes were observed in the striatum compared to the frontal cortex.
- ACTH(6-9)PGP more affected 152 genes in the striatum, primarily related to inflammation.
- Approximately 100 genes were commonly regulated by both peptides across both brain regions, linked to neuroactive ligand-receptor interaction.
Why It Matters
This research provides critical insights into the region-specific molecular mechanisms of ACTH(4-7)PGP (Semax) and ACTH(6-9)PGP in ischemic stroke. Understanding how these peptides modulate gene expression differently in the striatum versus the frontal cortex could enable more targeted neuroprotective strategies. For peptide users and clinicians, this suggests that the therapeutic effects of ACTH-like peptides might vary significantly depending on the specific brain region affected by ischemia, potentially guiding future protocol development for stroke recovery. While preclinical, these findings lay the groundwork for optimizing peptide selection and administration for specific stroke presentations, moving towards precision neuroprotection.
semax
acth-4-7pgp
acth-6-9pgp
ischemic-stroke
neuroprotection
gene-expression