Biochanin A enhances RORγ activity through STAT3-mediated recruitment of NCOA1

Abstract

Interleukin (IL)-17-producing T cells play important roles in autoimmunity, chronic inflammation and host protection against extracellular bacteria and fungi. The retinoic acid receptor-related orphan receptors (ROR) α and γ are key regulators of the IL-17-producing phenotype. We previously showed that the isoflavone biochanin A enhanced ROR-mediated transcriptional activity. Here, we investigated the possible mechanisms underlying this ROR activation. Biochanin A-treated murine thymoma EL4 and primary splenocytes demonstrated enhanced induction of IL-17. Biochanin A also induced tyrosine-phosphorylation of signal transducer and activator of transcription 3 (STAT3) in these cells. Stable knockdown of either RORγ or STAT3 in EL4 cells canceled biochanin A-induced upregulation of IL-17 expression. Importantly, biochanin A enhanced complex formation between RORγ and STAT3 or nuclear-receptor coactivator 1 (NCOA1). Furthermore, the biochanin A-induced RORγ-NCOA1 complex was disrupted by a dominant negative mutant of STAT3 or by the STAT3 specific inhibitor Stattic. These results suggest that biochanin A activates RORγ-dependent IL-17 transcription through the enhancement of STAT3 phosphorylation and STAT3-mediated recruitment of NCOA1 to RORγ.

Digoxin, an Overlooked Agonist of RORγ/RORγT

“…This was accompanied by increases in G6PC and NPAS2 promoter occupancy by RORγ, as evaluated using the ChIP technique (Figure 5). It is known that to show full transactivation potential, RORγ needs to interact with coactivators (Kurebayashi et al, 2004; Wang et al, 2010a; Kojima et al, 2015; Takahashi et al, 2017), which is why we next performed ChIP analysis using anti-NCOA1 (SRC-1) and anti-NCOA2 (SRC-2) antibodies to determine the status of these coactivators on the G6PC and NPAS2 promoters. Similar to the results for RORγ, digoxin treatment increased G6PC and NPAS2 promoter occupancy by NCOA1 and decreased G6PC and NPAS2 promoter occupancy by NCOA2 (Figure 5).…”

Can network pharmacology identify the anti-virus and anti- inflammatory activities of Shuanghuanglian oral liquid used in Chinese medicine for respiratory tract infection?

“…Both NCOA1 and NCOA2 are nuclear receptor coactivators that directly bind nuclear receptors and stimulate the transcriptional activities in a hormone-dependent fashion [57,58]. NCOA1 is capable of enhancing the level of retinoic acid receptors, the key regulators of interleukin-17, which play an important role in autoimmunity, chronic inflammation and host protection against extracellular bacteria and fungi [59]. NCOA2 is a transcriptional coactivator for steroid receptors and nuclear receptors.…”

Natural products as modulators of retinoic acid receptor-related orphan receptors (RORs)

“…Biochanin A, in particular, was shown to increase IL-17A mRNA levels RORa/gand STAT3-dependently and to enhance the interaction between RORgt and the co-activator NCOA1 as shown with immunoprecipitation and immunoblotting assays. 147,148 Furthermore, biochanin A increased STAT3 phosphorylation in a Src kinasedependent manner. 148 In another study, genistein treatment delayed the onset and reduced the severity of EAE.…”

“…147,148 Furthermore, biochanin A increased STAT3 phosphorylation in a Src kinasedependent manner. 148 In another study, genistein treatment delayed the onset and reduced the severity of EAE. Interestingly, genistein-treated mice had a lower expression level of RORgt and reduced production of IL-6 in the spinal cord, however, IL-17 levels were not changed.…”