The homeobox transcription factor VentX controls human macrophage terminal differentiation and proinflammatory activation
Xiaoming Wu, … , Roger W. Giese, Zhenglun Zhu
Xiaoming Wu, … , Roger W. Giese, Zhenglun Zhu
Published June 13, 2011
Citation Information: J Clin Invest. 2011;121(7):2599-2613. https://doi.org/10.1172/JCI45556.
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Research Article Immunology

The homeobox transcription factor VentX controls human macrophage terminal differentiation and proinflammatory activation

Abstract

Macrophages are critical players in both innate and adaptive immunity. While the exogenous signaling events leading to the terminal differentiation of macrophages from monocytes have been studied extensively, the underlying intracellular transcriptional mechanisms remain poorly understood. Here we report that the homeobox transcription factor VentX plays a pivotal role in human macrophage terminal differentiation and proinflammatory function. Our study showed that VentX expression was upregulated upon human primary monocyte-to-macrophage differentiation induced by cytokines such as M-CSF, GM-CSF, and IL-3. Moreover, ablation of VentX expression in primary monocytes profoundly impaired their differentiation to macrophages, and ectopic expression of VentX in a myeloid progenitor cell line triggered its differentiation with prominent macrophage features. Further analysis revealed that VentX was pivotal for the proinflammatory response of terminally differentiated macrophages. Mechanistically, VentX was found to control expression of proteins key to macrophage differentiation and activation, including M-CSF receptor. Importantly, preliminary analysis of gene expression in leukocytes from patients with autoimmune diseases revealed a strong correlation between levels of VentX and those of proinflammatory cytokines. Our results provide mechanistic insight into the crucial roles of VentX in macrophage differentiation and proinflammatory activation and suggest that dysregulation of VentX may play a role in the pathogenesis of autoimmune diseases.

Authors

Xiaoming Wu, Hong Gao, Weixiong Ke, Roger W. Giese, Zhenglun Zhu

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Figure 2

Knockdown of VENTX compromises the macrophage differentiation of primary monocytes.

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Knockdown of VENTX compromises the macrophage differentiation of primary...
(A) Knockdown of VENTX expression in primary monocytes by RNA interference. Monocytes were transfected with siRNA against GFP or VentX through electroporation. VENTX mRNA levels were determined by real-time PCR at 3 days after transfection (left); VentX protein level was determined by Western blotting at 4 days after transfection (right). (B) Effects of VENTX knockdown on macrophage morphogenesis during M-CSF–induced differentiation. Monocytes were transfected with either siGFP or siVentX and subsequently exposed to 100 ng/ml M-CSF. At 4 days after transfection, the morphology of macrophages was revealed by phase contrast microscopy (upper panel) and Wright-Giemsa staining (lower panel). Original magnification, ×200. Note: A portion of cells lost their original morphology during the Wright-Giemsa staining procedure. (C) Effects of VENTX knockdown on macrophage surface expression of CD71. Left panel: CD71 expression was not detected on cell surface of freshly isolated monocytes. Right panel: CD71 expression on M-CSF–treated monocytes at 4 days after siRNA transfection. Filled blue histogram represents the isotope control staining; red histogram represents monocytes transfected with siGFP; green histogram represents monocytes transfected with siVentX. (D) Bar graphs show mean + SD of 6 different experiments in C. Paired t test was used to reveal statistical significance. **P < 0.01.