TRAF3/STAT6 axis regulates macrophage polarization and tumor progression

• Published in: Cell death and differentiation Vol. 30; no. 8; pp. 2005 - 2016
• Main Authors: Shi, Jian-Hong, Liu, Li-Na, Song, Dan-Dan, Liu, Wen-Wen, Ling, Chen, Wu, Fei-Xiang, Wang, Ting-Ting, Liu, Bin, Cui, Nai-Peng, Qin, Yan, Ni, Zhi-Yu
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 01.08.2023; Nature Publishing Group UK
• Subjects: Animals; Cancer therapies; CD36 antigen; Genes; Interleukin 4; Interleukin-4 - metabolism; Interleukin-4 - pharmacology; Kinases; Macrophage Activation; Macrophages; Macrophages - metabolism; Melanoma; Metastases; Mice; NF-κB protein; Nitric oxide; Nitric-oxide synthase; Phenotype; Phenotypes; Polarization; Proteins; Signal Transduction; Stat6 protein; TNF Receptor-Associated Factor 3 - genetics; TNF Receptor-Associated Factor 3 - metabolism; TNF Receptor-Associated Factor 3 - pharmacology; Tumors; Ubiquitination
• ISSN: 1350-9047; 1476-5403; 1476-5403
• DOI: 10.1038/s41418-023-01194-1

Converting tumor-associated macrophages (TAMs) from the M2 to the M1 phenotype is considered an effective strategy for cancer therapy. TRAF3 is known to regulate NF-κB signaling. However, the role of TRAF3 in TAM polarization has not yet been completely elucidated. Here, we found that ablation of TRAF3 increased M1 markers, iNOS, FGR and SLC4A7, while down-regulated M2 markers, CD206, CD36 and ABCC3, expression levels in macrophages. Moreover, TRAF3 deficiency enhanced LPS-induced M1 and abolished IL-4-induced macrophage polarization. Next, quantitative ubiquitomics assays demonstrated that among the quantitative 7618 ubiquitination modification sites on 2598 proteins, ubiquitination modification of IL-4 responding proteins was the most prominently reduced according to enrichment analysis. STAT6, a key factor of IL-4 responding protein, K450 and K129 residue ubiquitination levels were dramatically decreased in TRAF3-deficient macrophages. Ubiquitination assay and luciferase assay demonstrated that TRAF3 promotes STAT6 ubiquitination and transcriptional activity. Site mutation analysis revealed STAT6 K450 site ubiquitination played a vital role in TRAF3-mediated STAT6 activation. Finally, B16 melanoma mouse model demonstrated that myeloid TRAF3 deficiency suppressed tumor growth and lung metastasis in vivo. Taken together, TRAF3 plays a vital role in M2 polarization via regulating STAT6 K450 ubiquitination in macrophages.