Viruses Make Fake Insulin-Like Peptides That Hijack Host Cell Growth Signaling to Boost Their Own Replication

Researchers used grouper iridovirus on grouper and zebrafish cells, characterizing VILP expression timing, secretion, and receptor activation. Receptor-specific inhibitors and IGF-1 stimulation experiments determined the functional effects on viral replication. Transcriptome analysis and a zebrafish in vivo model validated the signaling mechanism.

This reveals an entirely new strategy viruses use to manipulate their hosts — producing fake insulin-like peptides. Understanding viral peptide mimicry has implications for virology, immunology, and potentially metabolic disease, as these viral peptides could theoretically affect metabolic signaling in infected organisms.

The discovery of viral insulin-like peptides challenges the assumption that insulin/IGF signaling is exclusively a host system. If viruses have evolved to produce these mimicry peptides, they may contribute to metabolic disruption during infections. This also opens the door to using VILPs as tools for studying insulin/IGF receptor biology and potentially as templates for novel peptide drug design.

The study focused on fish iridoviruses, and it's unknown whether mammalian viruses employ similar insulin-like peptide mimicry strategies. The functional studies were primarily in fish cell lines and zebrafish, limiting direct human health relevance. The precise structural basis for VILPs' selective receptor interactions needs further characterization.