A B S T R A C TEthnopharmacological relevance: Qing Dai, a famous traditional Chinese medicine (TCM), is prepared by a traditional fermentation process with the aerial part of Strobilanthes cusia. Currently, this TCM could treat various clinical inflammatory diseases, such as ulcerative colitis and psoriasis, however, the bioactive components of Qing Dai are unknown clearly. Aim of the study: To isolate and identify the anti-IL-17A components of Qing Dai. Materials and methods: Silica, RP-18 gels, and size exclusion resin were used for column chromatography to isolate the pure compounds. The structures of isolates were elucidated by NMR, MS, UV, IR spectra, and optical rotation. IL-17A protein and gene expressions were also evaluated in the Th17 cell model and luciferase reporter assay, respectively. Results: Two indole alkaloids, including one new indigodole D and cephalandole B, were isolated from Qing Dai. Indigodole D could inhibit IL-17A protein production during the Th17 polarization (EC 50 : 2.16 μg/mL) or after the polarization (EC 50 : 5.99 μg/mL) without cytotoxicity toward Th17 cells. Cephalandole B did not inhibit the IL-17A protein secretion. Nevertheless, both isolates notably inhibited IL-17A gene expression, especially cephalandole B, in a dose-dependent manner in Jukat cells with IL-17A luciferase reporter. Conclusions: Indole alkaloids, indigodoles A, C, D, tryptanthrin, and indirubin could contribute to anti-IL 17A properties of Qing Dai. The possible biogenetic mechanisms of above-mentioned indoles were also speculated in this investigation for further promising anti-IL-17 lead drugs development.

Ability of IL‐17‐producing CD8+ T cells (Tc17) to transform into cytotoxic anti‐tumour effectors makes them a promising candidate for immune effector cell (IEC) therapy. However, key factors regulating Tc17 reprogramming remain poorly defined, hindering translation of Tc17‐based IEC use from bench to bedside. We probed the effects of multiple cytokines and underlying signalling pathways on Tc17 cells and identified pivotal role for IL‐4 and PI3K/AKT in promoting Tc17 transformation into cytotoxic IFN‐γ‐producing IECs, an effect dependent on Eomes expression. IL‐4 not only triggered Tc17 cytotoxicity, but also induced cell expansion, which significantly improved the antitumour potential of Tc17 cells compared to that of IFN‐γ‐producing CD8+ T cells (Tc1) in a murine model. Furthermore, IL‐4/AKT signalling drove the upregulation of the T‐cell receptor‐associated transmembrane adaptor 1 (Trat1) in Tc17 cells to promote IL‐4‐induced T‐cell receptor stabilization and Tc17 cytotoxicity. Finally, we proposed a possible procedure to expand human Tc17 from peripheral blood of cancer patients, and confirmed the function of IL‐4 in Tc17 reprogramming. Collectively, these results document a novel IL‐4/AKT/Eomes/Trat1 axis that promotes expansion and transformation of Tc17 cells into cytotoxic effectors with a therapeutic potential. IL‐4 priming of Tc17 cells should be further explored as a cell therapy engineering strategy to generate IECs to augment anti‐tumour responses.

Outbreak of coronavirus disease 2019 occurred in Wuhan and has rapidly spread to almost all parts of world. In coronaviruses, the receptor binding domain (RBD) in the distal part of S1 subunit of SARS-CoV-2 spike protein can directly bind to angiotensin converting enzyme 2 (ACE2). RBD promote viral entry into the host cells and is an important therapeutic target. In this study, we discovered that theaflavin showed the lower idock score (idock score: −7.95 kcal/mol). To confirm the result, we discovered that theaflavin showed FullFitness score of -991.21 kcal/mol and estimated ΔG of -8.53 kcal/mol for the most favorable interaction with contact area of SARS-CoV-2 RBD by SwissDock service. Regarding contact modes, hydrophobic interactions contribute significantly in binding and additional hydrogen bonds were formed between theaflavin and Arg454, Phe456, Asn460, Cys480, Gln493, Asn501 and Val503 of SARS-CoV-2 RBD, near the direct contact area with ACE2. Our results suggest that theaflavin could be the candidate of SARS-CoV-2 entry inhibitor for further study. 4 Keywords： SARS-CoV-2, spike protein, receptor binding domain, theaflavin