DDAH2 suppresses RLR-MAVS-mediated innate antiviral immunity by stimulating nitric oxide-activated, Drp1-induced mitochondrial fission.

Shan Huang, Zexing Li, Zewen Wu, Chang Liu, Minghang Yu, Mingjie Wen, Liyun Zhang, Xi Wang

Science signaling 2021 Apr 13

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The RIG-I-like receptor (RLR) signaling pathway is pivotal for innate immunity against invading viruses, and dysregulation of this molecular cascade has been linked to various diseases. Here, we identified dimethylarginine dimethylaminohydrolase 2 (DDAH2) as a potent regulator of the RLR-mediated antiviral response in human and mouse. Overexpression of DDAH2 attenuated RLR signaling, whereas loss of DDAH2 function enhanced RLR signaling and suppressed viral replication ex vivo and in mice. Upon viral infection, DDAH2 relocated to mitochondria, where it induced the production of nitric oxide (NO) and the activation of dynamin-related protein 1 (Drp1), which promoted mitochondrial fission and blocked the activation of innate immune responses mediated by mitochondrial antiviral signaling (MAVS). TANK-binding kinase 1 (TBK1), a kinase downstream of MAVS, inhibited DDAH2 by phosphorylating DDAH2 at multiple sites. Our study thus identifies a reciprocal inhibitory loop between the DDAH2-NO cascade and the RLR signaling pathway that fine-tunes the antiviral immune response. Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Citation

Shan Huang, Zexing Li, Zewen Wu, Chang Liu, Minghang Yu, Mingjie Wen, Liyun Zhang, Xi Wang. DDAH2 suppresses RLR-MAVS-mediated innate antiviral immunity by stimulating nitric oxide-activated, Drp1-induced mitochondrial fission. Science signaling. 2021 Apr 13;14(678)