Role of Peroxiredoxins in Regulating Intracellular Hydrogen Peroxide and Hydrogen Peroxide-induced Apoptosis in Thyroid Cells

Ho Kim,Tae-Hoon Lee,Eun Shin Park,Jae Mi Suh,Soo Jung Park,Hyo Kyun Chung,O-Yu Kwon,Young Kun Kim,Heung Kyu Ro,Minho Shong

doi:10.1074/jbc.275.24.18266

Ho Kim, Tae-Hoon Lee + Show 8 more

Open Access

https://doi.org/10.1074/jbc.275.24.18266

Copy DOI

Abstract

Peroxiredoxins (Prxs) play an important role in regulating cellular differentiation and proliferation in several types of mammalian cells. One mechanism for this action involves modulation of hydrogen peroxide (H(2)O(2))-mediated cellular responses. This report examines the expression of Prx I and Prx II in thyroid cells and their roles in eliminating H(2)O(2) produced in response to thyrotropin (TSH). Prx I and Prx II are constitutively expressed in FRTL-5 thyroid cells. Prx I expression, but not Prx II expression, is stimulated by exposure to TSH and H(2)O(2). In addition, methimazole induces a high level of Prx I mRNA and protein in these cells. Overexpression of Prx I and Prx II enhances the elimination of H(2)O(2) produced by TSH in FRTL-5 cells. Treatment with 500 micrometer H(2)O(2) causes apoptosis in FRTL-5 cells as evidenced by standard assays of apoptosis (i.e. terminal deoxynucleotidyl transferase deoxyuridine triphosphate-biotin nick end labeling, BAX expression, and poly(ADP-ribose) polymerase cleavage. Overexpression of Prx I and Prx II reduces the amount of H(2)O(2)-induced apoptosis measured by these assays. These results suggest that Prx I and Prx II are involved in the removal of H(2)O(2) in thyroid cells and can protect these cells from undergoing apoptosis. These proteins are likely to be involved in the normal physiological response to TSH-induced production of H(2)O(2) in thyroid cells.

Highlights

Peroxiredoxins (Prxs) play an important role in regulating cellular differentiation and proliferation in several types of mammalian cells
These results suggest that Prx I and Prx II are involved in the removal of H2O2 in thyroid cells and can protect these cells from undergoing apoptosis
Expression of Prx I and Prx II in Rat Tissues and in FRTL-5 Thyroid Cells—The expression of Prx I and Prx II was examined by Northern hybridization analysis using RNA from rat tissues (Fig. 1A)

Summary

EXPERIMENTAL PROCEDURES

Materials—Highly purified bovine TSH was from Sigma. The antibodies to peroxiredoxin isoforms were provided by Dr Rhee (NHLBI, National Institutes of Health, Bethesda, MD). Cell Culture—FRTL-5 rat thyroid cells (Interthyr Research Foundation, Baltimore, MD) were a fresh subclone (F1) that had all properties previously detailed [34]. Their doubling time with TSH was 36 Ϯ 6 h; without TSH, they did not proliferate. Transient transfections were carried out with FRTL-5 cells at 80% confluency [41] and 20 ␮g of pCRprx I and pCRprx II or equivalent molar amounts of the pCR3.1TM basic vector. Phosphate-buffered saline-washed FRTL-5 cells were stimulated with TSH (1 milliunit/ml), rapidly washed once with Krebs-Ringer solution, and incubated in Krebs-Ringer solution containing DCFH-DA (5 ␮g/ml). Significance between experimental values was determined by two-way analysis of variance

RESULTS

Peroxiredoxins and Oxidative Stress in Thyroid Cells

DISCUSSION