Suppression of Staphylococcal Enterotoxin B-induced Toxicity by a Nuclear Import Inhibitor

Area of Science:

• Immunology
• Molecular Biology
• Toxicology

Background:

• Staphylococcal enterotoxin B (SEB) and related toxins induce severe systemic inflammation, tissue damage, and mortality by targeting T cells.
• Inhibiting the nuclear import of stress-responsive transcription factors globally suppresses inflammatory gene expression.

Purpose of the Study:

• To investigate the efficacy of cell-permeant peptides targeting nuclear import adaptors as a countermeasure against SEB-induced toxicity.
• To evaluate the impact of inhibiting nuclear factor kappa B (NF-κB) import on inflammatory responses and survival in vivo.

Main Methods:

• Utilized cell-permeant peptides targeting Rch1/importin alpha/karyopherin alpha 2, a key nuclear import adaptor.
• Administered a cell-permeant cyclized SN50 peptide and a transgene suppressing NF-κB nuclear import in mouse models.
• Assessed the production of inflammatory cytokines (TNF-α, IFN-γ, IL-6), liver apoptosis, necrosis, and mortality rates.

Main Results:

• Cell-permeant peptides successfully delivered to T cells inhibited SEB-induced inflammatory cytokine production ex vivo and in vivo.
• Systemic production of TNF-α, IFN-γ, and IL-6 was significantly attenuated in treated mice.
• Reduced liver apoptosis and hemorrhagic necrosis correlated with decreased mortality rates.

Conclusions:

• Nuclear import inhibitors, specifically those targeting Rch1/importin alpha, represent a promising therapeutic strategy against SEB toxicity.
• Inhibiting the nuclear import of transcription factors like NF-κB offers a viable approach to mitigate harmful systemic inflammatory responses induced by SEB and similar toxins.