Arginine depletion-induced autophagy and metabolic dysregulation are involved in the disease severity of hand, foot, and mouth disease.

Amino acid metabolism provides significant insight into the development and prevention of many viral diseases. Therefore, the present study aimed to compare the amino acid profiles of hand, foot, and mouth disease (HFMD) patients with those of healthy individuals and to further reveal the molecular mechanisms of HFMD severity. Using UPLC-MS/MS, we determined the plasma amino acid expression profiles of pediatric patients with HFMD (mild, n = 42; severe, n = 43) and healthy controls (n = 25). Brain tissues from CVA6-infected mice were examined using untargeted metabolomics. Several amino acids were significantly different between the three groups. Pathway analysis revealed that arginine, proline, and tryptophan metabolism are implicated in the pathogenesis of HFMD. A similar arginine depletion was observed in the brain tissues of CVA6-infected mice. Importantly, L-arginine supplementation improved the survival rate of CVA6-infected mice, inhibited virus multiplication, and reduced pathological autophagy associated with mTOR-autophagy pathway in the brain. Collectively, arginine, as the hub amino acid metabolite of the mammalian target of rapamycin (mTOR) signaling pathway affecting autophagy, plays an important role in the pathogenesis of severe HFMD. L-arginine supplementation may serve as a potential therapeutic option for critical patients with HFMD.