The anti-TH17 polarization effect of Indigo naturalis and tryptanthrin by differentially inhibiting cytokine expression.

ETHNOPHARMACOLOGICAL RELEVANCE: The Chinese herbal medicine Qing-Dai (also known as Indigo naturalis) extracted from indigo-bearing plants including Baphicacanthus cusia (Ness) Bremek was previously reported to exhibit anti-psoriatic effects in topical treatment. TH17 was later established as a key player in the pathogenesis of psoriasis. We investigated the anti-TH17 effect of Indigo naturalis and its active compounds. The aim of this study is to evaluate the toxicity of Indigo naturalis (IN) and its derivatives on five cell types involved in psoriasis, and to study the anti-inflammatory mechanism for the toxicity. MATERIALS AND METHODS: Following the fingerprint and quantity analysis of indirubin, indigo, and tryptanthrin in IN extract, we used MTS kits to measure the anti-proliferative effect of IN and three active compounds on five different cell types identified in psoriatic lesions. Quantitative RT-PCR analysis was used to measure the expression of various genes identified in the activated keratinocytes and TH17 polarized gene expression in RORγt-expressing T cells. RESULTS: We showed that IN differentially inhibited the proliferation of keratinocytes and endothelial cells but not monocytes, fibroblasts nor Jurkat T cells. Among three active compounds identified in IN, tryptanthrin was the most potent compound to reduce their proliferation. In addition to differentially reducing IL6 and IL8 expression, both IN and tryptanthrin also potently decreased the expression of anti-microbial S100A9 peptide, CCL20 chemokine, IL1B and TNFA cytokines, independent of NF-κB-p65-activation. Their attenuating effect was also detected on the expression of signature cytokines or chemokines induced during RORγT-induced TH17 polarization. CONCLUSIONS: We were the first to confirm a direct anti-TH17 effect of both IN herbal extract and tryptanthrin.

Cystic Fibrosis Transmembrane Conductance Regulator: A Possible New Target for Photodynamic Therapy Enhances Wound Healing.

Objective: Cell migration is an essential process in skin wound healing. Photodynamic therapy (PDT) enhances wound healing by photoactivating a photosensitizer with a specific wavelength of light. Cystic fibrosis transmembrane conductance regulator (CFTR) is an ion channel expressed in multiple layers of keratinocytes. Recent studies showed that the activation of CFTR-related downstream signaling affects skin wound healing. We examined whether indocyanine green (ICG)-mediated PDT-enhanced cell migration is related to CFTR activation. Approach: The spatial and temporal expression levels of CFTR and proteins involved in focal adhesion, including focal adhesion kinase (FAK) and paxillin, were evaluated during cell migration in vitro and in vivo for wound healing. Results: ICG-PDT-conditioned medium collected from cells exposed to 5 J/cm2 near-infrared light in the presence of 100 µg/mL ICG activated CFTR and enhanced HaCaT cell migration. The expression of phosphorylated FAK Tyr861 and phosphorylated paxillin in focal adhesions was spatially and temporally regulated in parallel by ICG-PDT-conditioned medium. Curcumin, a nonspecific activator of CFTR, further increased PDT-enhanced cell migration, whereas inhibition of CFTR and FAK delayed cell migration. The involvement of CFTR in ICG-PDT-enhanced skin wound healing was confirmed in a mouse back skin wound model. Innovation: CFTR is a potential new therapeutic target in ICG-PDT to enhance wound healing. Conclusion: ICG-PDT-enhanced cell migration may be related to activation of the CFTR and FAK pathway. Conditioned medium collected from ICG-PDT may be useful for treating patients with chronic skin ulcer by regulating CFTR expression in keratinocytes.