A hedgehog cathelicidin-derived peptide exhibits antiviral activity against herpes simplex virus type 1 infection

Herpes simplex virus type 1 (HSV-1) is a widespread infectious virus that poses a substantial public health burden. With no specific curative therapy available and current antivirals providing only symptomatic relief, the development of new effective antiviral agents remains imperative. Antimicrobial peptides, particularly cathelicidins, are key immune effector molecules with antiviral and immunomodulatory properties. In this study, we found that European hedgehog skin extract (HSE) exhibited potent anti-HSV-1 activity, prompting us to investigate the contribution of the cathelicidin peptide CathEE. Based on this observation, three CathEE-derived antiviral peptides (CathEE-1, CathEE-2, and CathEE-3) were designed and further optimized to yield CathEE-2a and CathEE-2b. Notably, CathEE-2a displayed pronounced antiviral activity <i>in vitro</i> and significantly reduced brain viral loads in an HSV-1 mouse infection model. Histopathological analyses further revealed that CathEE-2a attenuated HSV-1-induced brain damage. Mechanistically, CathEE-2a suppressed HSV-1 infection by upregulating type I interferons and downstream antiviral genes. Collectively, these findings identify CathEE-2a as an immunomodulatory antiviral peptide and a promising lead candidate for the development of novel therapeutics against HSV-1 infection, highlighting the therapeutic potential of hedgehog-derived antimicrobial peptides in antiviral drug discovery.