Clonidine prevents radiation-induced cell death in human brain organoids

Radiotherapy is a standard treatment of pediatric brain tumors. Though the survival rate has improved for many tumor types, most patients suffer long-term cognitive decline and there is currently no way of preventing radiation-induced damage to healthy brain tissue. Here, we used a human forebrain organoid model to investigate if the α₂-adrenoceptor and I₁-imidazoline receptor agonist clonidine could prevent radiotoxicity. We found that treatment of organoids with clonidine significantly reduced radiation-induced loss of neural progenitor cells, neurons, astrocytes, and oligodendrocyte lineage cells. Moreover, clonidine reduced overall DNA damage and signs of reactive gliosis in organoids. Our findings demonstrate that pharmacological rescue of radiation neurotoxicity is possible in a human brain organoid model and provides a rationale for future drug repurposing studies aiming to prevent radiation-induced brain injury in children treated with radiotherapy.