Keratinocytes comprise the principal cell type in stratified squamous ephithelia (e.g., epidermis), major sites of chronic human disease. This proposal concerns several aspects of cross-linked envelope formation, a distinctive property of this cell type, in human and rat keratinocytes serially cultivated with 3T3 feeder layer support. First, the biochemical basis of envelope formation will be explored in light of our finding that considerable transglutaminase activity is membrane bound. The interaction of this enzyme with involucrin and other possible envelope constituents in membrane fractions will be explored to ascertain the mechanism of envelope cross-linking at the cell periphery. Second, our observation that culture conditions strongly modulate envelope forming ability will be extended, with emphasis on the actions of corticosteroids, retinoids and an unidentified serum factor. This factor will be characterized and, if possible, identified. We have found that keratinocytes grown under altered culture conditions or from different epithelia are distinguishable not only by envelope forming ability but also by toxic responses to 3-methylcholanthrene and 2,3,7,8-tetrachlorodibenzo-p-dioxin. A third aspect of the proposal is to examine in a systematic fashion cellular responses to these and other model toxic agents (PCBs, nitrosamines) in keratinocytes which exhibit intrinsic differences in regulation of envelope formation. The long range objectives of this work are 1) to provide a system for examining in keratinocytes the mechanisms of corticosteroid and retinoid action and effectiveness of pharmaceutical derivatives, 2) to improve human risk assessment in chemical testing, and 3) to provide a better understanding of keratinocyte physiology and intrinsic divergence, with special relevance to squamous metaplasia. In addition to culture studies, we propose to apply our method of immunoperoxidase staining of involucrin in paraffin embedded tissue sections to regions of squamous metaplasia and leukoplakia. This work may aid in recognition and differential diagnosis of neoplastic and perhaps other human keratinocyte lesions.
| Reznikova, Tatiana V; Phillips, Marjorie A; Rice, Robert H (2009) Arsenite suppresses Notch1 signaling in human keratinocytes. J Invest Dermatol 129:155-61 |
| Ngo, Mai A; Sinitsyna, Nadezda N; Qin, Qin et al. (2007) Oxygen-dependent differentiation of human keratinocytes. J Invest Dermatol 127:354-61 |
| Patterson, Timothy J; Rice, Robert H (2007) Arsenite and insulin exhibit opposing effects on epidermal growth factor receptor and keratinocyte proliferative potential. Toxicol Appl Pharmacol 221:119-28 |
| Lee, Young Jin; Rice, Robert H; Lee, Young Moo (2006) Proteome analysis of human hair shaft: from protein identification to posttranslational modification. Mol Cell Proteomics 5:789-800 |
| Rea, Miguel A; Zhou, Lei; Qin, Qin et al. (2006) Spontaneous immortalization of human epidermal cells with naturally elevated telomerase. J Invest Dermatol 126:2507-15 |
| Rice, Robert H; Crumrine, Debra; Uchida, Yoshikazu et al. (2005) Structural changes in epidermal scale and appendages as indicators of defective TGM1 activity. Arch Dermatol Res 297:127-33 |
| Patterson, Timothy J; Reznikova, Tatiana V; Phillips, Marjorie A et al. (2005) Arsenite maintains germinative state in cultured human epidermal cells. Toxicol Appl Pharmacol 207:69-77 |
| Lee, Chan; Lee, Young Moo; Rice, Robert H (2005) Human epidermal cell protein responses to arsenite treatment in culture. Chem Biol Interact 155:43-54 |
| Phillips, Marjorie A; Jessen, Bart A; Lu, Ying et al. (2004) A distal region of the human TGM1 promoter is required for expression in transgenic mice and cultured keratinocytes. BMC Dermatol 4:2 |
| Rea, Miguel A; Gregg, Jeff P; Qin, Qin et al. (2003) Global alteration of gene expression in human keratinocytes by inorganic arsenic. Carcinogenesis 24:747-56 |
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