JAK3 restrains inflammatory responses and protects against periodontal disease through Wnt3a signaling

Abstract

Homeostasis between pro- and anti- inflammatory responses induced by bacteria is critical for the maintenance of health. In the oral cavity, proinflammatory mechanisms induced by pathogenic bacteria are well-established; however, the anti-inflammatory responses that act to restrain innate responses remain poorly characterized. Here, we demonstrate that infection with the periodontal pathogen P. gingivalis enhances the activity of JAK3 in innate immune cells, and subsequently phospho-inactivates Nedd4-2, a ubiquitin E3 ligase. In turn, Wnt3 ubiquitination is decreased, while total protein levels are enhanced, leading to a reduction in proinflammatory cytokine levels. In contrast, JAK3 inhibition or Wnt3a robustly enhances NF-κB activity and the production of proinflammatory cytokines in P. gingivalis-stimulated innate immune cells. Moreover, using gain- and loss-of-function approaches, we demonstrate that downstream molecules of Wnt3a signaling, including Dvl3 and β-catenin, are responsible for the negative regulatory role of Wnt3a. In addition, using an in vivo P. gingivalis-mediated periodontal disease model, we show that JAK3 inhibition enhances infiltration of inflammatory cells, reduces expression of Wnt3a and Dvl3 in P. gingivalis-infected gingival tissues, and increases disease severity. Together, our results reveal a new anti-inflammatory role for JAK3 in innate immune cells and show that the underlying signaling pathway involves Nedd4-2-mediated Wnt3a ubiquitination.