Seung Hyun Shin

Volatile organic compound concentrations, emission rates, and source apportionment in newly-built apartments at pre-occupancy stage.

The present study investigated the indoor concentrations of selected volatile organic compounds (VOCs) and formaldehyde and their indoor emission characteristics in newly-built apartments at the pre-occupancy stage. In total, 107 apartments were surveyed for indoor and outdoor VOC concentrations in two metropolitan cities and one rural area in Korea. A mass balanced model was used to estimate surface area-specific emission rates of individual VOCs and formaldehyde. Seven (benzene, ethyl benzene, toluene, m,p-xylene, o-xylene, n-hexane, and n-heptane) of 40 target compounds were detectable in all indoor air samples, whereas the first five were detected in all outdoor air samples. Formaldehyde was also predominant in the indoor air samples, with a high detection frequency of 96%. The indoor concentrations were significantly higher than the outdoor concentrations for aromatics, alcohols, terpenes, and ketones. However, six halogenated VOCs exhibited similar concentrations for indoor and outdoor air samples, suggesting that they are not major components emitted from building materials. It was also suggested that a certain portion of the apartments surveyed were constructed by not following the Korean Ministry of Environment guidelines for formaldehyde emissions. Toluene exhibited the highest emission rate with a median value of 138 μg m(-2) h(-1). The target compounds with median emission rates greater than 20 μg m(-2) h(-1) were toluene, 1-propanol, formaldehyde, and 2-butanone. The wood panels/vinyl floor coverings were the largest indoor pollutant source, followed by floorings, wall coverings, adhesives, and paints. The wood panels/vinyl floor coverings contributed nearly three times more to indoor VOC concentrations than paints.

L-Ascorbic acid 2-phosphate promotes elongation of hair shafts via the secretion of insulin-like growth factor-1 from dermal papilla cells through phosphatidylinositol 3-kinase

Background  l‐Ascorbic acid 2‐phosphate (Asc 2‐P), a derivative of l‐ascorbic acid, promotes elongation of hair shafts in cultured human hair follicles and induces hair growth in mice.

Identification of transcriptional targets of Wnt/β-catenin signaling in dermal papilla cells of human scalp hair follicles: EP2 is a novel transcriptional target of Wnt3a

BACKGROUND Recent studies showed that Wnt signaling through the beta-catenin pathway (canonical Wnt signaling) act on mouse dermal papilla cells (DPCs) enabling hair follicles to keep growing. OBJECTIVE To investigate whether human DPCs respond to canonical Wnt signaling and, if so, to identify target genes of Wnt/beta-catenin pathway. METHODS Cultured human DPCs were transiently transfected with the beta-catenin responsive TCF reporter plasmid (pTopflash) and corresponding negative control reporter (pFopflash) to assess the activity of beta-catenin signaling by Wnt3a (one of the canonical Wnts). Immunofluorescence staining was also performed to localize beta-catenin in the presence or absence of Wnt3a. Microarray was carried out using Affymetrix gene chips. RT-PCR analysis and immunoblot were employed to verify microarray data. Cyclic AMP (cAMP) levels were measured using EIA assay after Wnt3a and PGE2 treatment in DPCs. RESULTS Wnt3a significantly stimulated the transcriptional activity of pTopflash but not pFopflash. In line with this, we identified a number of genes that are regulated by Wnt3a. Some of the differently expressed genes including EP2 were confirmed by RT-PCR analysis. Immunoblot further confirmed that EP2 protein is indeed increased by Wnt3a. DPCs pretreated with Wnt3a showed higher responsiveness to PGE2 as measured by cAMP levels. CONCLUSIONS Elucidation of the role of Wnt3a-regulated genes identified in this study including EP2 would help our understanding of hair-induction and maintenance of anagen phase.

Erythropoietin promotes hair shaft growth in cultured human hair follicles and modulates hair growth in mice

BACKGROUND Recent studies have shown that erythropoietin (EPO)/erythropoietin receptor (EPOR) signaling exist in both human and mouse hair follicles (HFs). OBJECTIVE To investigate whether dermal papilla cells (DPCs) express functional EPOR and, if so, to investigate effects of EPO on hair shaft growth in cultured human scalp hair follicles and hair growth in mice. METHODS EPOR expression in DPCs and follicular keratinocytes was examined by RT-PCR and immunoblot. Phosphorylation of EPOR signaling pathway mediators by EPO treatment was examined by immunoblot. MTT assay was employed to check cell viability after EPO treatment. Hair shaft growth was measured in the absence or presence of EPO and matrix keratinocyte proliferation was examined by Ki-67 immunostaining in cultured hair follicles. Agarose beads containing EPO were implanted into dorsal skin of C57BL/6 mice to examine effects of EPO on hair growth in vivo. RESULTS EPOR mRNA and protein are expressed in cultured human DPCs. EPOR signaling pathway mediators such as EPOR and Akt are phosphorylated by EPO in DPCs. EPO significantly promoted the growth of DPCs and elongated hair shafts with increased proliferation of matrix keratinocytes in cultured human hair follicles. In addition, EPO not only promoted anagen induction from telogen but also prolonged anagen phase. CONCLUSIONS EPO may modulate hair growth by stimulating DPCs that express functional EPOR.

Ecklonia cava promotes hair growth

Previous studies have reported the protective effects on skin elasticity of the edible marine seaweed Ecklonia cava, which acts through regulation of both antioxidative and anti‐inflammatory responses.

Baicalin, a flavonoid, affects the activity of human dermal papilla cells and promotes anagen induction in mice

Baicalin, a flavonoid isolated from Scutellaria baicalensis, is known to have multiple biological functions. Recent studies have demonstrated that baicalin treatment increases alkaline phosphatase activity (ALP) and osteoprotegerin secretion by osteoblasts. Furthermore, baicalin induces the differentiation of cultured osteoblasts via the activation of the Wnt/β-catenin signaling pathway. In this study, we evaluated the hair growth-promoting effects of baicalin in human follicular dermal papilla (DP) cells. A reporter assay and Western blotting were used to assess the effect of baicalin on β-catenin signaling in DP cells. ALP activity and messenger RNA (mRNA) expression were examined by ALP staining and real-time polymerase chain reaction (PCR), respectively. Growth factor expression levels were also evaluated using real-time PCR. Finally, the effect of baicalin on hair growth in vivo was examined by topical application of baicalin on the shaved dorsal skin of C57BL/6 mice. Our results indicate that baicalin activates Wnt/β-catenin signaling in a dose-dependent manner in human DP cells. ALP mRNA expression and activity were significantly induced in the presence of baicalin. In addition, treatment with baicalin induced the mRNA expression of growth factors, such as insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF). Moreover, compared to vehicle treatment, baicalin treatment induced an earlier conversion from telogen to anagen. Our results strongly suggest that baicalin promotes hair growth by regulating the activity of DP cells.

OVO Homolog-Like 1, a Target Gene of the Wnt/β-Catenin Pathway, Controls Hair Follicle Neogenesis

TO THE EDITOR A number of in vivo assays have been developed to measure the hair follicle– inducing ability (trichogenicity) of dermal and epidermal cell populations (reviewed by Ohyama et al., 2010; Yang and Cotsarelis, 2010). In all assays, dermal cells are considered inducers and epithelial cells responders during hair formation. The ‘‘patch assay’’ introduced by Zheng et al. (2005) has advantages of simplicity, low cell usage, and of multiple injections per mouse, and has been successfully used to measure the trichogenicity of dermal cells (Ito et al., 2007; Osada et al., 2007; Young et al., 2008; Zheng et al., 2010). Hair follicle neogenesis by follicular cell implantation is a promising option for the treatment of hair loss, and it is believed that the identification and evaluation of genes responsible for hair follicle neogenesis are important for the development of successful cell therapies. Recent studies have demonstrated that Wnt signaling through the b-catenin pathway maintains the trichogenicity of dermal papilla cells (Kishimoto et al., 2000; Shimizu and Morgan, 2004) and, thus, suggest that the b-catenin activity of dermal cells is correlated with trichogenicity and that genes transcriptionally targeted by the b-catenin pathway are essential for the maintenance of the trichogenicity of dermal cells. In this study, we adopted a small interfering RNA (siRNA)–mediated gene knockdown approach and a ‘‘patch assay’’ to confirm that b-catenin signaling in neonatal dermal cells is critical for the maintenance of trichogenicity. Subsequently, we found that the OVO homolog-like 1 (OVOL-1) gene is the transcriptional target of b-catenin, and thereafter we evaluated whether the expression level of OVOL-1 in neonatal dermal cells is correlated with trichogenicity. For the ‘‘patch assay,’’ dorsal skin was collected first from C57BL/6 mouse neonates (P0) and incubated overnight with 100 mg ml 1 collagenase/dispase (Roche, Mannheim, Germany) at 4 1C. The separated dermis and epidermis were subsequently digested with 0.25% trypsin in phosphate-buffered saline at 37 1C for 15 minutes, followed by filtration of the separated epidermal cells and dermal cells through 70 and 100mm cell strainers, respectively (Becton Dickinson, Franklin, NJ). Epidermal cells (total isolated cells from epidermis) were cultured in an EpiLife Medium (Invitrogen, Carlsbad, CA) in 5% CO2 at 37 1C, and dermal cells (total isolated cells from dermis) were cultured in DMEM supplemented with 10% fetal bovine serum (Gibco BRL, Gaithersburg, MD). The siRNAs used were purchased from Bioneer (Daejeon, Korea). Dermal cells were cultured as above for 24 hours and transfected with either control siRNA or b-catenin-specific siRNAs (b-catenin siRNA) at a final concentration of 10 nM in the presence of the RNAiMAX reagent (Invitrogen). A b-catenin siRNA with a significant knockdown efficiency (Figure 1a) was selected for further studies. To examine the effects of b-catenin knockdown on trichogenicity, cultured dermal cells were transfected with siRNAs, and 2 days post transfection 2 10 cells were LETTERS TO THE EDITOR

In Vivo Monitoring of Survival and Proliferation of Hair Stem Cells in a Hair Follicle Generation Animal Model

The purpose of this study was to investigate in vivo monitoring of hair follicle stem cells (newborn mouse fibroblasts [NFs]) expressing enhanced firefly luciferase (effluc) (NF-effluc) using noninvasive bioluminescence imaging (BLI). Effluc gene transduction into NFs was performed by retroviral vector, and effluc messenger ribonucleic acid expression and function were evaluated by reverse transcription–polymerase chain reaction and luciferase assay. After in vivo transplantation of NF-effluc cells to generate hair follicles, BLI was performed on days 1, 3, 7, 14, and 21 after transplantation. Additionally, hair follicle generation by the implanted stem cells was investigated using microscopy. The luciferase activity of NF-effluc was 41,175-fold higher compared to that of untransfected NFs. Bioluminescence signals from the transplantation site decreased gradually over 2 weeks; then the signal plateaued. Hair follicles were confirmed at the NF-effluc cell implantation site on day 14 after transplantation. We successfully monitored hair generation by hair stem cell implantation noninvasively with optical molecular strategy in an in vivo model.

Conditioned media obtained from human outer root sheath follicular keratinocyte culture activates signalling pathways that contribute to maintenance of hair‐inducing capacity and increases trichogenicity of cultured dermal cells

Findings from recent studies have demonstrated that hair‐inducing capacity (trichogenicity) of cultured dermal cells can be maintained by addition of conditioned media obtained from culture of epidermal keratinocytes. In this study, we investigated the question of whether treatment with human follicular keratinocyte–conditioned media (FKCM) can result in activation of signalling pathways that contribute to trichogenicity and increase the trichogenicity of cultured dermal cells. Through conduct of hair reconstitution assays, we observed that treatment of cells with FKCM resulted in induction of a greater number of hair follicles, compared with control cells. Treatment of dermal cells with FKCM resulted in the activation of BMP and β‐catenin signalling pathways. In addition, higher levels of IGFBP‐7, IL‐8, OPG and uPA were observed in FKCM. Altogether, our data suggest that a patients own FKCM would be ideal for expansion of the patients own follicular dermal cells for cell therapy for treatment of hair loss.

Extracellular histones inhibit hair shaft elongation in cultured human hair follicles and promote regression of hair follicles in mice

Release of histone H4 in rat vibrissa dermal papilla (DP) cells exposed to sub‐toxic dose of colchicines has been recently reported. In addition, exposure to histone H4 has been reported to result in inhibited proliferation and reduced alkaline phosphatase (ALP) activity of cultured vibrissa DP cells. These findings prompted us to investigate the role of extracellular histones in hair growth using cultured human hair follicles and hair cycling using back skin of mice. We report here that exposure of cultured hair follicles to histone H4 and H2A resulted in significant inhibition of elongation of hair shafts, decreased expression of IGF‐1 and decreased expression and activity of ALP. Injection of histones into hypodermis of mice during anagen resulted in premature onset of catagen. Findings of the current study provide strong evidence suggesting the inhibitory role of extracellular histones in hair growth.