6-Methoxyflavone Inhibits NFAT Translocation into the Nucleus and Suppresses T Cell Activation

Abstract

NFAT plays a crucial role in the immune system by regulating the transcription of inducible genes during immune responses. In T cells, NFAT proteins govern various cellular events related to T cell development, activation, tolerance induction, and differentiation. We previously reported the NFAT1-dependent enhancer activity of conserved noncoding sequence (CNS)-9, a distal cis-acting element, in the regulation of IL-10 transcription in T cells. In this study, we developed a T cell–based reporter system to identify compounds that modulate the regulatory activity of CNS-9. Among the identified candidates, 6-methoxyflavone (6-MF) significantly inhibited the enhancer activity of CNS-9, thereby reducing IL-10 expression in T cells without affecting cell viability. 6-MF also downregulated the transcription of NFAT1 target genes such as IL-4, IL-13, and IFN-γ. Treatment of 6-MF inhibited the translocation of NFAT1 into the nucleus, which consequently interrupted NFAT1 binding to the target loci, without affecting the expression or dephosphorylation of NFAT1. Treatment of 6-MF to CD4+ T cells or B cells isolated from mice with atopic dermatitis significantly reduced disease-associated cytokine production, as well as the levels of IgE. In addition, oral administration of 6-MF to atopic dermatitis mice ameliorated disease symptoms by reducing serum IgE levels and infiltrating lymphocytes. Conclusively, our results suggest that 6-MF can be a potential candidate for the development of an effective immunomodulator via the suppression of NFAT-mediated T cell activation.

The flavonoid 6-methoxyflavone allays cisplatin-induced neuropathic allodynia and hypoalgesia

“…6-Methoxyflavone (6-MF, Figure 1) belongs to the flavone class of flavonoids that acts as a flumazenil-insensitive positive allosteric modulator of GABA responses at human recombinant α1 ββL and αβ β2L GABA A receptors expressed in Xenopus laevis oocytes [17]. 6-MF has also been shown to possess an immunomodulatory property and this action stems from its ability to suppress NFAT-mediated T-cell activation [18]. In the present investigation, the antinociceptive effectiveness of 6-MF was studied using the well-known testing paradigms of both tonic nociception (acetic acid induced abdominal constriction test) and phasic nociception (hotplate and tail immersion tests).…”

Hydroxychloroquine inhibits CD154 expression in CD4+ T lymphocytes of systemic lupus erythematosus through NFAT, but not STAT5, signaling

“…Therefore we wanted to validate whether HCQ could inhibit nuclear translocation of NFATc2. Because a large amount of cells was needed for western blot analysis of NFAT, the immortalized cell line of human T lymphocyte cells (Jurkat cells) was used [ 43 ]. After pretreatment with vehicle or 10× standard concentration of HCQ (=6000 ng/ml) for 24 hours and stimulation with ionomycin for 2 hours, the nuclear and cytoplasmic fractions of Jurkat cells were extracted.…”

Role of CNSs Conserved Distal Cis-Regulatory Elements in CD4 + T Cell Development and Differentiation

“…Moreover, So et al ( 146 ) demonstrated that 6-Methoxyflavone inhibits Il-10 CNS9 activity by preventing NFAT1 nuclear translocation and disrupting its binding to this cis-regulatory element in mouse, ultimately causing IL-10 down-regulation. This mechanism reduces IL-10 production in activated T cells ( 146 ). IL-10 is a potential therapeutic target in various immune diseases due to its anti-inflammatory functions.…”

“…Their study revealed that Il-10 CNS9 enhancer activity in Th2 was mediated by NFAT1 and IRF4 ( Figure 2E ), which are two transcription factors upregulated upon TCR stimulation and boost IL-10 expression. Moreover, So et al ( 146 ) demonstrated that 6-Methoxyflavone inhibits Il-10 CNS9 activity by preventing NFAT1 nuclear translocation and disrupting its binding to this cis-regulatory element in mouse, ultimately causing IL-10 down-regulation. This mechanism reduces IL-10 production in activated T cells ( 146 ).…”