In spite of frequent usage of primary human foreskin keratinocytes (HFKs) in the study of skin biology, senescence-induced blockage of in vitro proliferation has been a big hurdle for their effective utilization. In order to overcome this passage limitation, we first isolated ten HFK lines from circumcision patients and successfully immortalized four of them via a retroviral transduction of high-risk human papillomavirus (HPV) E6 and E7 oncogenes. We confirmed expression of a keratinocyte marker protein, keratin 14 and two viral oncoproteins in these immortalized HFKs. We also observed their robust responsiveness to various exogenous stimuli, which was evidenced by increased mRNA expression of epithelial differentiation markers and pro-inflammatory genes in response to three reactive chemicals. In addition, their applicability to cytotoxicity assessment turned out to be comparable to that of HaCaT cells. Finally, we confirmed their differentiation capacity by construction of well-stratified three dimensional skin cultures. These newly established immortalized HFKs will be valuable tools not only for generation of in vitro skin disease models but also for prediction of potential toxicities of various cosmetic chemicals.
Antigens, Differentiation ; Biology ; Foreskin* ; Humans* ; In Vitro Techniques ; Keratin-14 ; Keratinocytes* ; Oncogene Proteins ; Oncogenes ; RNA, Messenger ; Skin Diseases ; Skin* ; Zidovudine

Silver nanoparticles (size: 7.9 +/- 0.95 nm, dosage: 250 mg/kg) were orally administered to pregnant rats. At 4 days after parturition, four pups were randomly selected (one pup from one dam) and silver level in liver, kidney, lung and brain was determined by ICP-MS and electron microscope. As results, silver nanoparticles highly accumulated in the tissues of the pups. Silver level in the treated group was 132.4 +/- 43.9 ng/g in the kidney (12.3 fold compared to control group), 37.3 +/- 11.3 ng/g in the liver (7.9 fold), 42.0 +/- 8.6 ng/g in the lung (5.9 fold), and 31.1 +/- 4.3 ng/g in the brain (5.4 fold). This result suggested that the possible transfer of silver nanoparticles from pregnant dams to the fetus through mainly placenta.
Animals ; Brain ; Electrons ; Fetus ; Kidney ; Liver ; Lung ; Nanoparticles ; Parturition ; Placenta ; Rats ; Silver