Chien-Hui Hong

Lifetime exposure to cigarette smoking and the development of adult-onset atopic dermatitis

Background  Adult‐onset atopic dermatitis (AD) has recently been recognized as a distinct disease entity, but its risk factors have not yet been clearly defined. Although gestational and perinatal exposure to tobacco smoking may be associated with the development of classic AD, the association between active/passive smoking and adult‐onset AD remains controversial.

ORAI1 Genetic Polymorphisms Associated with the Susceptibility of Atopic Dermatitis in Japanese and Taiwanese Populations

Atopic dermatitis is a chronic inflammatory skin disease. Multiple genetic and environmental factors are thought to be responsible for susceptibility to AD. In this study, we collected 2,478 DNA samples including 209 AD patients and 729 control subjects from Taiwanese population and 513 AD patients and 1027 control subject from Japanese population for sequencing and genotyping ORAI1. A total of 14 genetic variants including 3 novel single-nucleotide polymorphisms (SNPs) in the ORAI1 gene were identified. Our results indicated that a non-synonymous SNP (rs3741596, Ser218Gly) associated with the susceptibility of AD in the Japanese population but not in the Taiwanese population. However, there is another SNP of ORAI1 (rs3741595) associated with the risk of AD in the Taiwanese population but not in the Japanese population. Taken together, our results indicated that genetic polymorphisms of ORAI1 are very likely to be involved in the susceptibility of AD.

Mechanistic correlations between two itch biomarkers, cytokine interleukin-31 and neuropeptide β-endorphin, via STAT3/calcium axis in atopic dermatitis.

Summary Background  Itch is the cardinal symptom of atopic dermatitis (AD). β‐Endorphin, a neuropeptide, is increased in both AD skin and sera. Interleukin (IL)‐31, an itch‐relevant cytokine, activates IL‐31 receptors in keratinocytes. However, how IL‐31 and β‐endorphin interact in AD skin remains elusive.

IL-9 induces IL-8 production via STIM1 activation and ERK phosphorylation in epidermal keratinocytes: A plausible mechanism of IL-9R in atopic dermatitis.

BACKGROUND IL-9 and its receptor play important roles in the pathogenesis of asthma. Its role in atopic dermatitis (AD) was examined in just a few studies, including nucleotide polymorphisms, increased transcriptional levels of IL-9 and IL-9R in diseased skin, and an association of blood IL-9 levels with clinical severity. OBJECTIVE Little was known about the pathophysiological regulation of IL-9/IL-9R in AD skin. We asked whether IL-9R was expressed in epidermal keratinocytes; if so, what the functional outcome, cytokine production, and signaling pathway of IL-9/IL-9R in keratinocytes are. METHODS We measured and compared the expression of IL-9R in skin from AD patients and controls by immunofluorescence. We also performed in vitro studies on the IL-9-treated primary keratinocytes, including flow cytometry for IL-9R expressions, Western blotting for mTOR, S6K, ERK, p38, and STAT3 activations, ELISA for cytokine levels, and immunofluorescence for STIM1. RESULTS We found that IL-9R was indeed expressed in keratinocytes but not in fibroblasts. Its expression in keratinocytes was enhanced by IL-4 but not by TGF-beta1. IL-9 induced a moderate production of IL-8 but not CXCL16, CCL22, TSLP, nor IL-33. IL-9 induced formation of STIM1-puncta. IL-9 induced ERK phosphorylation both dose- and time-dependently, but not mTOR, S6K, p38, or STAT3. Pretreatment with U0126 (ERK inhibitor) but not rapamycin (mTOR inhibitor) abrogated the IL-9-mediated IL-8 production. Blockage of STIM1 with BTP2 or SKF96265 abrogated ERK phosphorylation and IL-8 production induced by IL-9. CONCLUSION This study represents the first to show the regulation of the IL-9-STIM1-ERK-IL-8 axis in keratinocyte, and how the axis might play an important role in the pathophysiology of AD.

Transforming growth factor‐β enhances matrix metalloproteinase‐2 expression and activity through AKT in fibroblasts derived from angiofibromas in patients with tuberous sclerosis complex

Background  Patients with tuberous sclerosis complex (TSC) develop fibrous tumours in the brain, skin, kidney, heart and lungs due to TSC1/2 mutations. In the skin, patients develop angiofibromas that have vascular and fibrotic components in which transforming growth factor (TGF)‐β and matrix metalloproteinase (MMP)‐2 are important.

STAT3-dependent VEGF production from keratinocytes abrogates dendritic cell activation and migration by arsenic: A plausible regional mechanism of immunosuppression in arsenical cancers

Arsenic remains an important environmental hazard that causes several human cancers. Arsenic-induced Bowens disease (As-BD), a skin carcinoma in situ, is the most common arsenical cancer. While great strides have been made in our understanding of arsenic carcinogenesis, how host immunity contributes to this process remains unknown. Patients with As-BD have an impaired contact hypersensitivity response. Although impaired T cell activation has been well-documented in arsenical cancers, how dendritic cell (DC), the key cell regulating innate immunity, regulates the immune response in arsenical cancers remains unclear. Using myeloid derived DC (MDDC) from patients with As-BD and normal controls as well as bone marrow derived DC (BMDC) from mice fed with or without arsenic, we measured the migration of DC. As-BD patients showed an impaired CCL21-mediated MDDC migration in vitro. Arsenic-fed mice had defective DC migration toward popliteal lymph nodes when injected with allogenic BMDCs via foot pad. Using skin from As-BD and normal controls, we found an increased expression of STAT3, a transcriptional factor contributing to impaired DC activation. Arsenic induced STAT3 activation and the production of VEGF in keratinocytes. The increase in VEGF was blocked by inhibiting STAT3 with RNA interference or pharmaceutically with JSI-124. While VEGF by itself minimally induced the expression of CD86 and MHC-II in MDDC, arsenic induced-MDDC activation was abolished by VEGF pretreatment. We concluded that the STAT3-VEGF axis in keratinocytes inhibits DC migration in the microenvironment of As-BD, indicating that cellular interactions play an important role in regulating the disease course of arsenical cancers.

CCR7 expression correlates with subcutaneous involvement in mycosis fungoides skin lesions and promotes migration of mycosis fungoides cells (MyLa) through mTOR activation

BACKGROUND The molecular pathogenesis of mycosis fungoides (MF) is currently poorly understood. The chemokine receptor CCR7 has been demonstrated to be involved in the development and progression of certain cancers, but its role in MF has rarely been investigated. OBJECTIVES We seek to determine whether CCR7 is expressed in MF skin lesions. In addition, we evaluate whether CCR7 plays a role in MF cell proliferation and migration, and which signaling pathways are involved. METHODS Immunohistochemical staining of 21 cases of MF pathology specimens with CCR7 was performed. Medical charts and pathology slides of these cases were reviewed. Surface expression of CCR7 on MyLa cells (MF cell line) and peripheral blood mononuclear cells (PBMCs) was assessed by flow cytometry. Cell proliferation and migration were evaluated with the Alamar Blue assay and transwell chemotaxis assay, respectively. RESULTS CCR7 was found to be expressed in 62% (13 out of 21) of MF pathology specimens, and its expression correlated with subcutaneous extension of lymphoma cells. CCR7 expression was increased on the surface of MyLa cells compared to that on PBMCs. Addition of CCL21 (CCR7 agonist) enhanced MyLa cell migration but not proliferation. The CCL21-induced MyLa cell migration was found to be mediated by the mTOR pathway. CONCLUSIONS CCR7 is more likely to be expressed in MF skin lesions with subcutaneous involvement. Activation of CCR7 promotes migration of MyLa cells (MF cell line) through the mTOR pathway. These findings provide new insights into the significance of CCR7 in the pathophysiology of MF.

Dermal dendritic cells, but not Langerhans cells, are critical in murine single epicutaneous sensitization.

A murine repeated protein‐patch model has been established to study epicutaneous sensitization in atopic dermatitis. This model has shown a predominant Th2 and a weak Th1 response in both BALB/c and C57BL/6 mice. However, Th responses induced in the repeated model are not consistent with the generally accepted theory that BALB/c and C57BL/6 mice are Th2 and Th1 prone and are representatives of human atopy and non‐atopy, respectively. In this study, a single protein‐patch model was established, which showed in addition to the Th2 response, a remarkable Th1 response in C57BL/6 mice, but not in BALB/c mice. Moreover, using muLangerin‐DTR mice, we demonstrated that dermal dendritic cells, but not Langerhans cells, are critical in single epicutaneous sensitization in both strains of mice.

Pyrrolo[2,1-c][1,4]benzodiazepine and indole conjugate (IN6CPBD) has better efficacy and superior safety than the mother compound DC-81 in suppressing the growth of established melanoma in vivo.

Melanoma is one of the most chemo-resistant cancers. The remission rate of current therapy remains low. Pyrrolo[2,1-c][1,4]benzodiazepines (PBDs) are a group of antitumor antibiotics that binds to N2 of guanine to form a DNA adduct. However, significant cardiotoxicity hampers their clinical use. We have previously synthesized a PBD indole conjugate (IN6CPBD) that induced apoptosis in several cancer cell lines. The purpose of this study was to assess the efficacy and safety of the IN6CPBD for established murine melanoma cells in vivo. IN6CPBD induced more apoptosis than DC-81 as evidenced by sub-G1 distribution, annexin V positivity, and decrease mitochondrial membrane potential (DeltaPsi(mt)). The melanomas were established in C57BL/6 mice by injecting B16F10 cells via the tail vein. Three courses of therapy were instituted after day 5 and the mice were sacrificed at day 20. The tumor growth rate in the foot pad was significantly reduced in IN6CPBD-treated mice than that in DC-81- and PBS-treated mice. The tumor burden in the lungs was also reduced significantly in IN6CPBD-treated mice accompanied with the most prominent TUNEL staining. Renal function, and cardiac enzymes were not altered significantly by IN6CPBD or DC-81, however, robust deterioration of liver function was noticed in the DC-81-treated mice. In summary, potent apoptosis could be elicited by the PBD indole conjugate IN6CPBD, accompanied with a better efficacy and less liver function impairment than the mother compound DC-81 in treating established melanoma metastasis in vivo.

Differential immunological effects of infrared irradiation and its associated heat in vivo

Infrared irradiation (IR) is the most abundant fraction of sunlight reaching the earths surface and provides heat. The fever response of an animal is known to regulate its immune responses. However, the non-thermal immune responses of IR were difficult to assess owing to its close association with heat. We hypothesized that IR irradiation induced differential immunological responses, independent of its associated heat. With an IR machine coupled with a delicate temperature control system, we investigated the non-thermal immunological effects of IR in vivo. With heating at 37 °C or 39 °C using an electric blanket or IR irradiation, we measured the skins physiological parameters, including transepidermal water loss (TEWL), pH, skin hydration, elasticity, sebum production, and skin blood flow. We also measured the number of Langerhans cells in epidermal sheets and draining lymph nodes. Lymph node cells were activated by anti-CD3 antibody and their production of interleukin (IL)-5, 10, 13, 17, and interferon (IFN)-γ was measured by enzyme-linked immunosorbent assay (ELISA). The result showed that compared to heating alone, IR causes an enhanced activation of epidermal Langerhans cells, both in epidermal sheets and in draining lymph nodes. The activation of draining lymph node cells by anti-CD3 antibody in vitro induces both Th2 and Th1, but not Treg immune responses. Interestingly, IL-13, a Th2 cytokine, is induced the most. In contrast, physiological parameters and barrier functions of skin were not altered after IR irradiation. The study showed that IR alone without heat modulates immune responses in vivo, indicating that IR irradiation might regulate host immunity in a heat-independent manner.