Lipin-2 degradation elicits a proinflammatory gene signature in macrophages

Lipin-2 is a phosphatidate phosphatase with key roles in regulating lipid storage and energy homeostasis. LPIN2-genetic deficiency is associated with an autoinflammatory disorder, underscoring its critical role in innate immune signaling; however, the regulatory mechanisms underlying protein stability remain unknown. Here, we demonstrate that Lipin-2 interacts with beta-TRCP, a substrate receptor subunit of the SCF beta-TRCP E3 ligase, and undergoes ubiquitination and proteasomal degradation. beta-TRCP-knockout in RAW264.7 macrophages resulted in Lipin-2 accumulation, leading to the suppression of LPS-induced MAPK activation and subsequent proinflammatory gene expression. Consistent with this, treatment with MLN4924, a Cullin-neddylation inhibitor that suppresses SCF E3 activity, increased Lipin-2 protein and concomitantly decreased Il1b expression. These findings suggested that beta-TRCP-mediated Lipin-2 degradation affects macrophage-elicited proinflammatory responses and could lead to new therapeutic approaches to treat inflammatory diseases. (C) 2020 Elsevier Inc. All rights reserved.