The long range goal of this research is to demonstrate that cultured human proximal tubule (HPT) cells are a valid, and possibly singular, model system for the study of human metal- and agent-induced nephropathies that invoke induction of the metallothionein stress response. It is well- established that the metallothioneins (MTs) are important in the renal response to toxiC insult, especially as it applies to heavy metal exposure and the resulting proximal tubular necrosis. However, it is not as well- known that the gene organization of MT between humans and rodents is quite different. Whereas the rodent has two coordinately regulated MT genes, MT1 and MT2, the human possesses 7 functional genes for MT-1 and one for MT-2; none of which appear to be coordinately regulated. It is not known if this increase in gene number is important in the human renal response to toxic agents or simply represents a needless duplication of function. As such, the initial experimental aim in this validation process is to determine the expression of the individual MT genes in cultured human proximal tubule cells (HPT) under basal conditions and following exposure to agents known to induce renal-toxicity. This response will then be compared to the MT response known to occur in animal model systems. The agents to be employed are copper, silver, cadmium, zinc, mercury and lead (control) . The second specific aim of this validation process will be to determine which MT genes are intimately involved in attenuating or enhancing human agent-induced renal toxicity. This will be determined for expressed MT genes by selectively inhibiting expression using antisense technology and for unexpressed MT genes by eliciting expression by transient transfection of the unexpressed gene into the HPT cells. Together, the above studies should validate the HPT cell system for use in experimental studies defining the mechanism of heavy metal toxicity in humans and, at the very least, allow replacement of primary cultures of similar cells isolated from animal species.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES007687-03
Application #
2459017
Study Section
Special Emphasis Panel (SRC (R))
Project Start
1995-08-01
Project End
1998-07-31
Budget Start
1997-08-01
Budget End
1998-07-31
Support Year
3
Fiscal Year
1997
Total Cost
Indirect Cost
Name
West Virginia University
Department
Pathology
Type
Schools of Dentistry
DUNS #
191510239
City
Morgantown
State
WV
Country
United States
Zip Code
26506
Kim, D; Somji, S; Garrett, S H et al. (2001) Expression of hsp 27, hsp 60, hsc 70, and hsp 70 by immortalized human proximal tubule cells (HK-2) following exposure to heat shock, sodium arsenite, or cadmium chloride. J Toxicol Environ Health A 63:475-93
Garrett, S H; Belcastro, M; Sens, M A et al. (2001) Acute exposure to arsenite induces metallothionein isoform-specific gene expression in human proximal tubule cells. J Toxicol Environ Health A 64:343-55
Somji, S; Todd, J H; Sens, M A et al. (2000) Expression of heat shock protein 60 in human proximal tubule cells exposed to heat, sodium arsenite and CdCl(2). Toxicol Lett 115:127-36
Garrett, S H; Sens, M A; Todd, J H et al. (1999) Expression of MT-3 protein in the human kidney. Toxicol Lett 105:207-14
Somji, S; Todd, J H; Sens, M A et al. (1999) Expression of the constitutive and inducible forms of heat shock protein 70 in human proximal tubule cells exposed to heat, sodium arsenite, and CdCl(2). Environ Health Perspect 107:887-93
Somji, S; Sens, D A; Garrett, S H et al. (1999) Heat shock protein 27 expression in human proximal tubule cells exposed to lethal and sublethal concentrations of CdCl2. Environ Health Perspect 107:545-52
Garrett, S H; Somji, S; Todd, J H et al. (1998) Differential expression of human metallothionein isoform I mRNA in human proximal tubule cells exposed to metals. Environ Health Perspect 106:825-31
Friedline, J A; Garrett, S H; Somji, S et al. (1998) Differential expression of the MT-1E gene in estrogen-receptor-positive and -negative human breast cancer cell lines. Am J Pathol 152:23-7
Garrett, S H; Somji, S; Todd, J H et al. (1998) Exposure of human proximal tubule cells to cd2+, zn2+, and Cu2+ induces metallothionein protein accumulation but not metallothionein isoform 2 mRNA. Environ Health Perspect 106:587-95
Hoey, J G; Garrett, S H; Sens, M A et al. (1997) Expression of MT-3 mRNA in human kidney, proximal tubule cell cultures, and renal cell carcinoma. Toxicol Lett 92:149-60

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