Regulation of Neuroinflammation by Microglial DUBA-IRAK1-IKKβ Signaling Loop

Activation of microglia is closely associated with neuroinflammation. However, the cell-intrinsic molecular mechanisms translating microglia activation into neuroinflammation are only partially understood. Here, it is shown that deubiquitinating enzyme A (DUBA) is upregulated in microglia under neuroinflammatory conditions in both mice and humans. Mechanistically, activation of microglia induces DUBA self-deubiquitination and stabilization, leading to the rapid upregulation of DUBA protein levels. In turn, stabilized DUBA increases proinflammatory gene induction in activated microglia by enhancing the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling. Of note, DUBA promotes NF-κB and MAPK activation by stabilizing interleukin-1 receptor activated kinase 1 (IRAK1) through K48 deubiquitination. Importantly, specific ablation of DUBA in microglia mitigates lipopolysaccharide-induced depression-like behavior and ischemic stroke injury in mice by limiting neuroinflammation. Collectively, these findings establish DUBA as a key regulator of microglia in neuroinflammation and uncover novel molecular mechanisms for DUBA in inflammatory signal transduction.