HIF-1α Is Up-Regulated in Activated Mast Cells by a Process That Involves Calcineurin and NFAT

Abstract

Mast cells play important roles in many pathological conditions where local hypoxia is observed, including asthma, rheumatic diseases, and certain types of cancer. Here, we investigated how expression of the hypoxia-inducible factor 1, α subunit gene (HIF1A), is regulated in mast cells. The product of HIF1A is hypoxia-inducible factor 1α (HIF-1α), is a major nuclear transcription factor modulating gene expression in response to hypoxic conditions. We observed that under hypoxic conditions, exposure of mast cells to ionomycin and substance P resulted in significant up-regulation of HIF1A expression as compared with resting mast cells incubated under identical conditions. The ionomycin-mediated increase in HIF-1α protein levels was sensitive to the transcription inhibitor actinomycin D and to inhibitors of calcineurin, cyclosporin A (CsA), and FK506. The increased HIF-1α protein level was paralleled by a severalfold increase in HIF-1α mRNA that could be also inhibited with actinomycin D and CsA. The HIF1A promoter activity was significantly increased in ionomycin-activated mast cells, and the promoter activity could be inhibited by CsA and FK506. Furthermore, in situ mutagenesis experiments showed that the ionomycin-mediated HIF1A promoter activity depends on a conservative NFAT-binding site. Thus, accumulation of HIF-1α in activated mast cells requires up-regulation of HIF1A gene transcription and depends on the calcineurin-NFAT signaling pathway.

The supernatant of apoptotic cells causes transcriptional activation of hypoxia-inducible factor–1α in macrophages via sphingosine-1-phosphate and transforming growth factor-β

“…To show direct binding of NFAT to the HIF-1␣ promoter, we used the described NFAT-binding sequence of the HIF-1␣ promoter for EMSA analysis. 23 Treatment of RAW264.7 cells with CM AC-J enhanced binding of NFAT to the promoter sequence, which again could be reversed when cells were exposed to CsA ( Figure 6C). Supershift experiments with the NFATc1 AB proved the specificity of the oligonucleotide-protein complex.…”

“…In macrophages, lipopolysaccharide (LPS) induced nuclear factor (NF)-B binding to the HIF-1␣ promoter and increased its mRNA expression. 22 Nuclear factor of activated T cells (NFAT)c1 increased the HIF-␣ mRNA content in mast cells after stimulation with ionomycin, 23 and signal transducer and activator of transcription (STAT)3 up-regulated HIF-1␣ mRNA in human tumor cells, 24 substantiating the importance of transcriptional control mechanisms governing HIF-1 appearance/activity.…”

“…In macrophages, lipopolysaccharide (LPS) induced nuclear factor (NF)-B binding to the HIF-1␣ promoter and increased its mRNA expression. 22 Nuclear factor of activated T cells (NFAT)c1 increased the HIF-␣ mRNA content in mast cells after stimulation with ionomycin, 23 and signal transducer and activator of transcription (STAT)3 up-regulated HIF-1␣ mRNA in human tumor cells, 24 substantiating the importance of transcriptional control mechanisms governing HIF-1 appearance/activity.We provide evidence that HIF-1␣ under normoxia is transcriptionally activated via NFAT in response to apoptotic cell-derived S1P and TGF-␤. As verified in cells from HIF-1␣ conditional knockout mice, activation of HIF-1 in polarized macrophages moderates differentiation of embryonic stem cells toward CD31-positive cells.…”

NFAT control of innate immunity

“…73 Mast cell activation during hypoxia has also been shown to depend on NFAT signaling. 74 Activation of high affinity IgE receptor (Fc⑀RI) leads to the release of regulatory factors stored in mast cell granules, 75 which can enhance mast cell survival. 76,77 Recently, the mechanism of this prolonged survival has been linked to the NFAT-dependent transcription of the antiapoptotic Bcl2 family member gene A1/Bfl-1.…”

The critical role of mast cell‐derived hypoxia‐inducible factor‐1α in human and mice melanoma growth

“…Previous researchers reported that HIF-1a was highly expressed in mast cells under hypoxic conditions. [16][17][18] To assess the inhibitory effects of H1 receptor antagonists on the expression of HIF-1a and infiltration of mast cells, we performed an immunohistochemistry for mast cells and HIF-1a. The immunohistochemical analysis of the intratumoral tissue sections revealed that HIF-1a is highly expressed in the nuclear of the control group; whereas in the H1 receptor antagonist (terfenadine or promethazine)-treated mice, it is decreased (Fig.…”