Carbonic anhydrases in human keratinocytes and their regulation by all‐
            trans
            retinoic acid and 1α,25‐dihydroxyvitamin D
            3

Cultured podocytes easily lose expression of nephrin. In this report, we developed optimum media for recovery and maintenance of nephrin gene expression in murine podocytes. Using reporter podocytes, we found that activity of the nephrin gene promoter was enhanced by DMEM/F12 or α-MEM compared with RPMI-1640. In any of these basal media, addition of 1,25-dihydroxyvitamin D3, all- trans-retinoic acid or dexamethasone significantly increased activity of the nephrin promoter. The effects of the supplemental components were synergistic, and the maximum activation was achieved by DMEM/F12 supplemented with three agents. This culture medium was designated as vitamin D3, retinoic acid and dexamethasone-supplemented DMEM/F12 (VRADD). In reporter podocytes that express nephrin, VRADD induced activation of the nephrin gene promoter up to 60-fold. Even in podocytes that have lost nephrin expression during multiple passages, expression of nephrin mRNA was dramatically recovered by VRADD. However, VRADD caused damage of podocytes in prolonged cultures, which was avoided in the absence of dexamethasone (designated as VRAD). VRAD maintained expression of nephrin for extended periods, which was associated with the differentiated phenotype of podocytes. Using the VRAD-primed podocytes, we revealed that expression of nephrin mRNA as well as nephrin promoter activity was suppressed by a putative dedifferentiation factor of podocytes, hepatocyte growth factor.

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Differential Effects of All-Trans Retinoic Acid on the Growth of Human Keratinocytes and Mouth Carcinoma Epidermoid Cultures. Involvement of GRIM-19 and Complex I of the Respiratory Chain

International Journal of Immunopathology and Pharmacology ◽

10.1177/039463200702000407 ◽

2007 ◽

Vol 20 (4) ◽

pp. 719-729 ◽

Cited By ~ 10

Author(s):

F. Papa ◽

M. Delia ◽

R. Trentadue ◽

D. Panelli ◽

F. Bellomo ◽

...

Keyword(s):

Retinoic Acid ◽

Cell Growth ◽

Respiratory Chain ◽

Complex I ◽

Human Keratinocytes ◽

Mitochondrial Respiratory Chain ◽

Oxidoreductase Activity ◽

Trans Retinoic Acid ◽

All Trans Retinoic Acid ◽

Normal Human

Squamous cell carcinoma (SSC) is the most frequent malignant tumor of the oral cavity. A study on the effect of all-trans retinoic acid (RA) on cell growth, expression of GRIM-19 and content and activity of complex I of the mitochondrial respiratory chain in normal human keratinocytes (NHEK) and mouth carcinoma cells with low (HN) and high (KB) transformation grade was carried out. In NHEK cells, RA treatment resulted in growth suppression, significant overexpression of GRIM-19 protein, enhanced content of complex I but depressed activity of NADH-UQ oxidoreductase activity of the complex. In HN cells, RA treatment depressed cell growth, inhibited the enzymatic activity of complex I but had no significant effect on the levels of GRIM-19 and complex I. In KB cells RA had no effect on cell growth, GRIM-19 expression, content and activity of complex I.

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