7.      Immortalisation and characterisation of balding and non-balding dermal papilla cell lines and their response to oxidative stress. 
Adiam W Bahta, Dermatology (QMUL), London, UK

The dermal papilla (DP) expresses androgen receptors and is known to control normal hair growth. The paradox of androgen action in human hair growth is well established but the molecular mechanisms in hair follicles are poorly understood. DP cells derived from frontal (balding) human scalp hair follicles (BDPC) are used to study Androgenetic alopecia. However, cultured BDPC are very difficult to obtain, grow very slowly in vitro and have a limited life span of 2-6 passages before they senescence (see other abstract). We have recently shown that BDPC express senescence-associated beta galactosidase activity at PH-6. Moreover, stress induced premature senescence was induced with more prominent characteristic behaviour in BDPC than non balding DPC (NBDPC) after exposure to sub-cytotoxic levels of H2O2. However, the limited life span of BDPC represents a substantial obstacle for biochemical analysis, genetic manipulation and screens. We therefore, generated immortalized balding and non-balding human DP cells (IBDPC, INBDPC) by ectopic expression of human telomerase. The IBDPC have undergone more than 90 passages without showing any phenotypic changes. As with the primary DPC, the IBDPC maintained their aggregating characteristics and expressed wnt7a, wnt3a, androgen receptor and 5 alpha reductase type 2 mRNA. We established an in vitro co-culture system by growing IBDPC and INBDPC with keratinocytes (KC) to study the androgen effects in hair follicles. Androgen suppressed the growth of KC when grown with IBDPC and this could be partially reversed using a neutralising antibody to TGF-beta1. In addition we have also observed that IBDPC retains increased sensitivity towards H2O2 than INBDPC cell lines. Therefore, immortalised DP cell lines show similar characteristics to primary DPC and they will be of major help to us in our attempt to understand the actions of androgens on hair growth and enable the development of better treatment for androgen dependent hair disorders.