Culture of hair matrix and follicular keratinocytes

Human Derived Immortalized Dermal Papilla Cells With a Constant Expression of Testosterone Receptor

Androgenetic alopecia (AGA) is the most common type of hair loss, and is mainly caused by the biological effects of testosterone on dermal papilla cells (DPCs). In vitro culturing of DPCs might be a useful tool for the screening of target molecule of AGA. However, primary DPCs cannot continuously proliferate owing to cellular senescence and cell culture stress. In this study, we introduced mutant cyclin-dependent kinase 4 (CDK4), Cyclin D1, and telomerase reverse transcriptase (TERT) into DPCs. We confirmed protein expression of CDK4 and Cyclin D1, and enzymatic activity of TERT. Furthermore, we found the established cell line was free from cellular senescence. We also introduced the androgen receptor gene using a recombinant retrovirus, to compensate the transcriptional suppressed endogenous androgen receptor in the process of cell proliferation. Furthermore, we detected the efficient nuclear translocation of androgen receptor into the nucleus after the treatment of dihydrotestosterone, indicating the functionality of our introduced receptor. Our established cell line is a useful tool to identify the downstream signaling pathway, which activated by the testosterone.

IL6 and the human limbal stem cell niche: a mediator of epithelial-stromal interaction

The corneal epithelium is maintained by the limbal epithelial stem cells (LESCs). In this study, an in vitro model is proposed for the investigation of cell-cell interactions involving LESC maintenance. Imaging of the limbal niche demonstrated close spatial arrangement between basal limbal epithelial cells within putative LESC niche structures and fibroblasts in the stroma. Interactions of the human limbal epithelial (HLE) cells and mitotically active human limbal fibroblasts (HLF) were studied for the first time in a serum-free in vitro model that simulated aspects of the limbal niche microenvironment. HLE cocultured in a ratio 3:1 with HLF exhibited enhanced expression of the putative stem cell markers ABCG2 and p63α and holoclones were preserved as shown by colony-forming efficiency assays, clonal analysis, and colony characterisation. Interleukin 6 (IL6) was found to be up-regulated in the 3.1SF system when compared to the HLE culture with growth-arrested fibroblasts and serum (gold standard system, GS). IL6 caused a time-dependent phosphorylation of STAT3 in HLE cells. STAT3 and IL6 inhibition in 3.1SF cultures significantly reduced HLE colony-forming efficiency, suggesting a previously undetected STAT3-mediated involvement of IL6 in the maintenance of HLE cells in a progenitor-like state.

Isolation and cultivation of human keratinocytes from skin or plucked hair for the generation of induced pluripotent stem cells

The ease of generating induced pluripotent stem (iPS) cells, and possibly their properties after reprogramming, depends on the origin of the somatic cell starting population. Reprogramming of keratinocytes is both faster and more efficient compared with fibroblasts, although more care is required when isolating, culturing and infecting these cells. In this study, we describe detailed protocols using both feeder-dependent and defined serum- and feeder-free conditions for culturing human keratinocytes from foreskin samples and punch biopsies, as well as how to isolate keratinocytes from plucked hair. We further describe culture techniques and approaches to efficiently infect and reprogram these cells for the purpose of generating iPS cells. The procedure of deriving keratinocytes takes 10-14 d, whereas reprogramming and the appearance of iPS cell colonies that can be isolated and established requires another 3-4 weeks.

Penetration Profile of Microspheres in Follicular Targeting of Terminal Hair Follicles

The transfollicular administration of pharmacologically active molecules is of current therapeutic interest, mainly with regard to delivery to specific sites of the hair follicle (HF) and the reduction of hepatic metabolism and systemic toxicity. HF are privileged pathways for specific molecules depending on formulations, which enter faster into these shunts than through the stratum corneum. The aim was to optimize the delivery of fluorescent microspheres into the HF, thereby, developing a standardized protocol for follicular targeting with microspheres. The number of HF showing penetration, as well as the depth of penetration, was determined. Freshly excised skin samples with terminal HF were divided into groups, with or without prior treatment with cyanoacrylate skin surface stripping-technique (CSSS). Thereafter microspheres at a size of 0.75-6.0 microm were applied according to the developed standardized protocol. Skin biopsies were obtained, shock-frozen, and sectioned in 5 microm slices. We demonstrated a selective penetration route of the microspheres into the HF. Optimal microsphere size proved to be approximately 1.5 microm, with a 55% rate of all HF, and with a maximum penetration depth of >2300 microm. Without previous CSSS treatment of the skin, the transfollicular microsphere penetration was below 27% with a maximum penetration depth of 1000 microm. Thus, the basis for follicular targeting of essential structures containing stem cells for keratinocytes, melanocytes, and mast cells has been laid.

Loose anagen syndrome and loose anagen hair

Loose anagen syndrome, or loose anagen hair, is a recently described condition of unknown etiology that may be under-recognized. The typical patient is a child with sparse fine hair that can easily be pulled out. The diagnosis is confirmed by microscopic examination of firmly pulled hairs, many of which are in the anagen phase but lacking an inner and outer root sheath and demonstrating a ruffled cuticle. Some presentations of alopecia areata may be confused with this condition, but the pull test analysis serves to differentiate them. A variety of theories have been postulated to explain the pathophysiology of loose anagen syndrome. In some cases, there is an autosomal dominant pattern of inheritance. In most cases, this condition spontaneously improves with age.

Role of androgens in the developmental biology of the pilosebaceous unit

The growth and development of pilosebaceous units in their characteristic pattern depends on the interaction of androgens and diverse biologic factors. Stromal-epithelial interactions are essential features. Considerable evidence suggests that androgens stimulate the growth of sensitive pilosebaceous units primarily by acting on specific stromal cells and that androgens and retinoic acid interact to regulate specific stages of sebocyte differentiation.