Nur77 deficiency leads to systemic inflammation in elderly mice

Abstract

Background: Nur77, an orphan member of the nuclear receptor superfamily, has been implicated in the regulation of inflammation. However, the in vivo function of Nur77 remains largely unexplored. In the current study, we investigated the role of Nur77 in inflammation and immunity in mice. Findings: We found that elderly 8-month-old Nur77-deficient mice (Nur77-/-) developed systemic inflammation. Compared to wild-type (WT) mice (Nur77+/+), Nur77-/- mice showed splenomegaly, severe infiltration of inflammatory cells in several organs including liver, lung, spleen and kidney, increased hyperplasia of fibrous tissue in the lung and enlargement of kidney glomeruli. Additionally, Nur77-/- mice had increased production of pro-inflammatory cytokines and immunoglobulin, and elicited pro-inflammatory M1-like polarization in macrophages as revealed by increased expression of CXCL11 and INDO, and decreased expression of MRC1. Conclusions: These in vivo observations provide evidence for a pivotal role for Nur77 in the regulation of systemic inflammation and emphasize the pathogenic significance of Nur77 in vivo.