Molcular Reguration of Parathyroid Cell Function in Chronic Renal Failure

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Recent data suggest that deranged gene reguration underlie the parathy-roid dysfunction in chronic failure. However, the mechanism of this abnormality has not been fully elucidated at cellular level because no estsblished parathyroid cell line is practically available.To modulate funnction of diapersed parathyroid cells which maintain physiological response to extracellular only for a few days, we transfered functional genes by adenovirus vector.1.Analysis of Vitamin D Receptor (VDR) Density and Cell Prolifiration in Parathyroid Hyperplasia.Immunohistochemistry of serial section of surgically exsized parathyroid glands from uremic patients revealed that positive rate of VDR and proliferating cell nuclear antigen (PCNA) had significant negative coreration. Further more, cells in small nodule forming within diffuse parathyroid hyperplasia had low density of VDR and higher positive rate of PCNA compared with surrounding cells. These data suggest more direct coreration between decreased de … More nsity of VDR and cell proliferation in chronic renal failure.2.Gene Transfer into Parathyroid Cells by AdenovirusSurgically excised parathyroid glands were dispersed by collagenase and 5x105cells in 0.5ml of DMEM/F12 (FBS10%) were cultured in each well of 24-well dish. On the next day, replication-deficient adenoviral vector that contained a reporter gene enconding thenuclear b-galactosidase driven by CAG promoter was added at 1x107pfu/ml or less. X-gal staining was positive in almost all cells at 48hours of infection. At this point, adenovirus infection itsself did not affect the cell number BrdU incorporation. Basal and phisiolosical response of PTH secretionto low and high calcium ion concentration were not affected by viral infection either. Thus, successful gene transfer was accomplished by adenoviral vectors in parathyroid cells which still maintained physiological response to calcium.Furthermore, we could also successfully infect parathyroid cells in vivo by directly injecting virus solution. Next we constracted recommbinant adenovirus which expresses human VDR gene under CAG promoter. Trnsfer of VDR gene into dispersed parathyroid cells by this virus lead to significant suppression of PTH secretion in the presense of 1/10 of physiological concentration of calcitoriol.Thus, it may soon become possible to modulate parathyroid function in vivo by trnsferring functional genes by adenovirus vector. Less