BACKGROUND: Nkx2.5 is a homeodomain-containing nuclear transcription protein that has been associated with acute T-lymphoblastic leukemia. In addition, Nkx2.5 has an essential role in cardiomyogenesis. However, the expression of Nkx2.5 in the skin has not been investigated. OBJECTIVE: In an attempt to screen the differentially regulated genes involved in keratinocyte differentiation, using a cDNA microarray, we identified Nkx2.5 as one of the transcription factors controlling the expression of proteins associated with keratinocyte differentiation. METHODS: To investigate the expression of Nkx2.5 during keratinocyte differentiation, we used a calcium-induced keratinocyte differentiation model. RESULTS: RT-PCR and Western blot analysis revealed that the expression of Nkx2.5, in cultured human epidermal keratinocytes, increased with calcium treatment in a time-dependent manner. In normal skin tissue, the expression of Nkx2.5 was detected in the nuclei of the keratinocytes in all layers of the epidermis except the basal layer by immunohistochemistry. In addition, the expression of Nkx2.5 was significantly increased in psoriasis and squamous cell carcinoma, but was barely detected in atopic dermatitis and basal cell carcinoma. CONCLUSION: These results suggest that Nkx2.5 may play a role in the change from proliferation to differentiation of keratinocytes and in the pathogenesis of skin disease with aberrant keratinocyte differentiation.
Blotting, Western ; Calcium ; Carcinoma, Squamous Cell ; Dermatitis, Atopic ; Epidermis ; Humans ; Immunohistochemistry ; Keratinocytes ; Leukemia ; Oligonucleotide Array Sequence Analysis ; Proteins ; Psoriasis ; Skin ; Skin Diseases ; Transcription Factors

BACKGROUND: Arachidonic acid (AA) is an omega-6 polyunsaturated fatty acid present in all mammalian cell membranes, and involved in the regulation of many cellular processes, including cell survival, angiogenesis, and mitogenesis. The dermal papilla, composed of specialized fibroblasts located in the bulb of the hair follicle, contributes to the control of hair growth and the hair cycle. OBJECTIVE: This study investigated the effect of AA on hair growth by using in vivo and in vitro models. METHODS: The effect of AA on human dermal papilla cells (hDPCs) and hair shaft elongation was evaluated by MTT assay and hair follicle organ culture, respectively. The expression of various growth and survival factors in hDPCs were investigated by western blot or immunohistochemistry. The ability of AA to induce and prolong anagen phase in C57BL/6 mice was analyzed. RESULTS: AA was found to enhance the viability of hDPCs and promote the expression of several factors responsible for hair growth, including fibroblast growth factor-7 (FGF-7) and FGF-10. Western blotting identified the role of AA in the phosphorylation of various transcription factors (ERK, CREB, and AKT) and increased expression of Bcl-2 in hDPCs. In addition, AA significantly promoted hair shaft elongation, with increased proliferation of matrix keratinocytes, during ex vivo hair follicle culture. It was also found to promote hair growth by induction and prolongation of anagen phase in telogen-stage C57BL/6 mice. CONCLUSION: This study concludes that AA plays a role in promoting hair growth by increasing the expression of growth factors in hDPCs and enhancing follicle proliferation and survival.
Animals ; Arachidonic Acid* ; Blotting, Western ; Cell Membrane ; Cell Survival ; Fibroblasts ; Hair Follicle ; Hair* ; Humans ; Immunohistochemistry ; Intercellular Signaling Peptides and Proteins ; Keratinocytes ; Mice ; Organ Culture Techniques ; Phosphorylation ; Transcription Factors

BACKGROUND: Ecklonia cava is a brown alga that contains various compounds, including carotenoids, fucoidans, and phlorotannins. E. cava polyphenols (ECPs) are known to increase fibroblast survival. The human dermal papilla cell (hDPC) has the properties of mesenchymal-origin fibroblasts. OBJECTIVE: This study aims to investigate the effect of ECPs on human hair growth promotion in vitro and ex vivo. METHODS: MTT assays were conducted to examine the effect of ECPs on hDPC proliferation. Hair growth was measured using ex-vivo hair follicle cultures. Real-time polymerase chain reaction was performed to evaluate the mRNA expression of various growth factors in ECP-treated hDPCs. RESULTS: Treatment with 10 microg/ml purified polyphenols from E. cava (PPE) enhanced the proliferation of hDPCs 30.3% more than in the negative control (p<0.001). Furthermore, 0.1 microg/ml PPE extended the human hair shaft 30.8% longer than the negative control over 9 days (p<0.05). Insulin-like growth factor-1 (IGF-1) mRNA expression increased 3.2-fold in hDPCs following treatment with 6 microg/ml PPE (p<0.05). Vascular endothelial growth factor (VEGF) mRNA expression was also increased 2.0-fold by 3 microg/ml PPE (p<0.05). Treatment with 10 microg/ml PPE reduced oxidative stress in hDPCs (p<0.05). CONCLUSION: These results suggest that PPE could enhance human hair growth. This can be explained by hDPC proliferation coupled with increases in growth factors such as IGF-1 and VEGF. Reducing oxidative stress is also thought to help increase hDPCs. These favorable results suggest that PPE is a promising therapeutic candidate for hair loss.
Carotenoids ; Fibroblasts ; Hair Follicle ; Hair* ; Humans* ; Insulin-Like Growth Factor I ; Intercellular Signaling Peptides and Proteins ; Oxidative Stress ; Polyphenols* ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; Vascular Endothelial Growth Factor A