( em C /em ) Expression of D3 in human tissues and skin cells: (1,9) DNA ladder; (2) pituitary; (3,4) normal skin; (5) BCC; (6) myometrium; (7) follicular keratinocytes; (8) epidermal keratinocytes; (10) epidermal melanocytes; (11C13) SBCE2,WM35, and WM98 melanomas, respectively. samples. Expression of functional thyroid-stimulating hormone receptor in the skin may have significant physiologic and pathologic consequences, particularly in autoimmune conditions associated with production of stimulating antibodies against the thyroid-stimulating hormone receptor. We conclude that the expanding list of neuroendocrine elements expressed in the IL18RAP skin supports a strong role for this system in cutaneous biology. production of thyroid hormones in human skin has not yet been demonstrated, although epidermal keratinocytes may be capable of deiodinating thyroxine (T4) and T3 (reviewed in Slominski and Wortsman, 2000). Fibroblasts of human dermal and orbital origin have been reported to express thyroid-stimulating hormone receptors (TSH-R) (Wu identify reverse transcriptionC PCR products of TSH-R (367 bp), NIS (303 bp), and thyroglobulin (395 bp) transcripts. (1) HaCaT keratinocytes; (2C4) WM 35,WM 164, and WM 1341D, SBCE2 respectively; (5) SKMEL188 melanoma; (6) negative control no template; (7,8) normal thyroid. in stable cell lines positive for TSH-R (HaCaT keratinocytes and four different melanoma lines, e.g., SWM 35, WM164, WM1341D), and also in one line negative for TSH-R (SKMEL188). The lines expressing TSH-R also coexpressed thyroglobulin and NIS genes, whereas the SKMEL188 line was negative for these genes (Fig 1). All of these lines were negative for thyroid peroxidase gene (not shown). Thus, expression of some, but not all molecular elements of the TSH-R-related pathways that are characteristic for the thyroid is conserved in cultured skin cells. Recent studies have shown NIS expression in lactating breast tissue and in some breast cancers (Spitzweg marked 227 bp (D2a) and 335 bp (D2b) transcripts. ( em C /em ) Expression of D3 in human tissues Remetinostat and skin cells: (1,9) DNA ladder; (2) pituitary; (3,4) normal skin; (5) BCC; (6) myometrium; (7) follicular keratinocytes; (8) epidermal keratinocytes; (10) epidermal melanocytes; (11C13) SBCE2,WM35, and WM98 melanomas, respectively. ( em D /em ) Expression of TRH-R: (1) DNA ladder; (2) pituitary; (3,4) SKMEL188 and WM1341D melanomas, respectively. ( em E /em ) Expression of TRH: (1,10) DNA ladder; (2) nonlesional human skin; (3) dermal fibroblasts; (4) hair follicle papilla fibroblasts; (5) melanoma WM1341D; (6) neonatal keratinocytes; (7) adrenal gland; (8) myometrium; (9) placenta. em TSH /em As we had found functional expression of TSH-R in the skin, we tested for its natural ligand (TSH) to investigate paracrine or autocrine Remetinostat control of TSH-R activity. Aside from its expression in the pituitary control, TSH gene expression was observed in epidermal and hair follicle keratinocytes, hair follicle melanocytes, squamous cell carcinoma, and two melanoma lines, as well as myometrium, being absent in all other cells or tissues tested that included biopsies of whole skin (Fig 3 em A /em ; Table II). This pattern suggests that TSH expression is not constitutive, but instead responds to environmental stimulation exemplified, in this case, by the conditions of cell culture and/or by random depression during malignant progression. D2 and D3 genes The D2 gene product (227 bp) was expressed Remetinostat in almost all tested samples; the sole exception was a line of hair follicle melanocytes where it was below detectable levels (Fig 3 em B /em Remetinostat ; Table II). In some biopsies of normal skin (one of four) and skin containing BCC (one of three), an additional second transcript of 335 bp was detected. It corresponds to the b isoform of D2 (D2b, accession no. “type”:”entrez-nucleotide”,”attrs”:”text”:”AB041843″,”term_id”:”10863064″,”term_text”:”AB041843″AB041843). D2b contains an additional exon (insertion of 108 bp) with an in-frame TGA codon that may encode an extra selenocysteine (Ohba em et al /em , 2001). This second isoform (335 bp) was also present in neonatal, epidermal, follicular and HaCaT keratinocytes, dermal and follicular papilla fibroblasts, epidermal melanocytes, squamous cell carcinoma cells, and the SBCE2 melanoma line (Fig 1 em B /em ). The detection of the second isoform is consistent with the recent findings of two additional splicing.