SLIT2 as a key regulator and therapeutic target in liver injury.

Drug-induced liver injury accounts for approximately 10% of acute hepatitis and up to 50% of acute liver failure. Despite its clinical significance, treatment remains largely limited to cessation of the offending agent. SLIT/ROBO signaling, known for roles in organ development, angiogenesis, leukocyte migration, and cancer metastasis, has demonstrated protective effects against various organ damage. In mouse models of liver injury induced by acetaminophen (APAP), thioacetamide, bile duct ligation, and serum from patients with toxic liver disease, Slit2 expression significantly increases, while Slit1 and Slit3 remain unchanged. Liver-specific Slit2 knockdown exacerbates liver injury, whereas recombinant SLIT2 alleviates liver damage by reducing oxidative stress via CYP2E1 downregulation and suppressing inflammation through nuclear factor κB inhibition. Notably, among ROBO receptors, only ROBO4 was induced in hepatocytes after APAP exposure. ROBO4 knockdown eliminates the hepatoprotective effects of SLIT2, highlighting the importance of SLIT2/BOBO4 signaling in toxic liver injury. Furthermore, the novel Slit2-derived peptide 5 (SP5), designed from the ROBO4-binding LRR2 domain, significantly reduces liver damage and inflammation. Notably, both recombinant SLIT2 and SP5 confer hepatoprotection even when administered 24 h after APAP challenge. These findings suggest that SLIT2/ROBO4-targeted therapies may offer a promising approach for preventing fulminant hepatitis in the context of toxic liver injury.