Macrophage metabolic reprogramming presents a therapeutic target in lupus nephritis

Significance IgG antibodies are a key component of adaptive humoral immunity but can cause organ damage if they bind self-antigen, as occurs in the autoimmune disease systemic lupus erythematosus (SLE). Many of the proinflammatory effects of IgG are mediated by ligating Fcγ receptors (FcγRs) expressed by tissue-resident leukocytes such as macrophages. One of the most serious complications of SLE is kidney inflammation: lupus nephritis. Here we show that IgG ligation of FcγRs on macrophages in the kidney leads to a change in their metabolism, resulting in a switch toward glycolysis. Administration of a glycolysis inhibitor attenuated IgG-associated kidney macrophage activation, proinflammatory cytokine secretion, and kidney inflammation. Therefore, manipulating macrophage metabolism may be a useful therapeutic strategy in lupus nephritis.
IgG antibodies cause inflammation and organ damage in autoimmune diseases such as systemic lupus erythematosus (SLE). We investigated the metabolic profile of macrophages isolated from inflamed tissues in immune complex (IC)-associated diseases, including SLE and rheumatoid arthritis, and following IgG Fcγ receptor cross-linking. We found that human and mouse macrophages undergo a switch to glycolysis in response to IgG IC stimulation, mirroring macrophage metabolic changes in inflamed tissue in vivo. This metabolic reprogramming was required to generate a number of proinflammatory mediators, including IL-1β, and was dependent on mTOR and hypoxia-inducible factor (HIF)1α. Inhibition of glycolysis, or genetic depletion of HIF1α, attenuated IgG IC-induced activation of macrophages in vitro, including primary human kidney macrophages. In vivo, glycolysis inhibition led to a reduction in kidney macrophage IL-1β and reduced neutrophil recruitment in a murine model of antibody-mediated nephritis. Together, our data reveal the molecular mechanisms underpinning FcγR-mediated metabolic reprogramming in macrophages and suggest a therapeutic strategy for autoantibody-induced inflammation, including lupus nephritis.