Transcription factor NFAT5 promotes macrophage survival in rheumatoid arthritis
Susanna Choi, … , Chul-Soo Cho, Wan-Uk Kim
Susanna Choi, … , Chul-Soo Cho, Wan-Uk Kim
Published February 13, 2017
Citation Information: J Clin Invest. 2017;127(3):954-969. https://doi.org/10.1172/JCI87880.
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Research Article Immunology Inflammation

Transcription factor NFAT5 promotes macrophage survival in rheumatoid arthritis

Abstract

Defective apoptotic death of activated macrophages has been implicated in the pathogenesis of rheumatoid arthritis (RA). However, the molecular signatures defining apoptotic resistance of RA macrophages are not fully understood. Here, global transcriptome profiling of RA macrophages revealed that the osmoprotective transcription factor nuclear factor of activated T cells 5 (NFAT5) critically regulates diverse pathologic processes in synovial macrophages including the cell cycle, apoptosis, and proliferation. Transcriptomic analysis of NFAT5-deficient macrophages revealed the molecular networks defining cell survival and proliferation. Proinflammatory M1-polarizing stimuli and hypoxic conditions were responsible for enhanced NFAT5 expression in RA macrophages. An in vitro functional study demonstrated that NFAT5-deficient macrophages were more susceptible to apoptotic death. Specifically, CCL2 secretion in an NFAT5-dependent fashion bestowed apoptotic resistance to RA macrophages in vitro. Injection of recombinant CCL2 into one of the affected joints of Nfat5+/– mice increased joint destruction and macrophage infiltration, demonstrating the essential role of the NFAT5/CCL2 axis in arthritis progression in vivo. Moreover, after intra-articular injection, NFAT5-deficient macrophages were more susceptible to apoptosis and less efficient at promoting joint destruction than were NFAT5-sufficient macrophages. Thus, NFAT5 regulates macrophage survival by inducing CCL2 secretion. Our results provide evidence that NFAT5 expression in macrophages enhances chronic arthritis by conferring apoptotic resistance to activated macrophages.

Authors

Susanna Choi, Sungyong You, Donghyun Kim, Soo Youn Choi, H. Moo Kwon, Hyun-Sook Kim, Daehee Hwang, Yune-Jung Park, Chul-Soo Cho, Wan-Uk Kim

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Figure 3

Molecular targets of NFAT5 involving RAW 264.7 macrophage survival and proliferation.

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Molecular targets of NFAT5 involving RAW 264.7 macrophage survival and p...
(A–C) Comparative analysis of the transcriptomes in RAW 264.7 macrophages with NFAT5 shRNA (n = 3), control shRNA (n = 3), and NFAT5 decoy oligonucleotides (n = 3). Global gene expressions profiles were determined using the Illumina MouseWG-6 v2.0 array platform. (A) Venn diagram illustrates the overlap between DEGs in macrophages stably transfected with NFAT5 shRNA (NFAT5 KD) and those transduced stably with NFAT5 decoy oligonucleotides (TGGAAAATTACCG, NFAT5 decoy). (B) Heatmap showing differential expression patterns of 2,261 DEGs in NFAT5 KD and the NFAT5 decoy compared with the corresponding controls. (C) Cellular processes enriched by 1,074 (Down) and 819 (Up) DEGs in the same direction between NFAT5 KD and the NFAT5 decoy. Significantly enriched processes for common DEGs were scored with respect to the P value obtained. Selected processes were grouped into 9 functional classes on the basis of the similarity of gene ontology terms defined by the kappa score. The color gradient on the right represents the enrichment score defined as –log10 (P value). Enrichment scores are displayed in a violet color gradient: dark violet (P < 0.01), bright violet (P < 0.05), and white (P > 0.05). The significance of the enrichment was determined using a hypergeometric test. (D) Network model describing the functional modules, which are functionally aggregated with the DEGs associated with cell proliferation, apoptosis, and survival. Node color represents upregulated (red) and downregulated (turquoise) gene expression in NFAT5 KD and the NFAT5 decoy compared with control. Gray lines indicate interactions between 2 genes. Expression levels of the genes marked with an asterisk were confirmed by real-time PCR in Figure 3E. (E) mRNA expression levels of representative NFAT5-regulated genes involved in cell survival, proliferation, and apoptosis in NFAT5 KD RAW 264.7 macrophages (upper panel) and NFAT5 shRNA–transfected human macrophages (lower panel), as determined by real-time PCR. Data represent the mean ± SD of 3 independent experiments performed in duplicate.