Fig. 3.

Macrophages from PTP1B-deficient mice exhibit increased apoptosis and phagocytosis, and fail to restore GSH levels after 5 Gy irradiation. (A) BMDM from WT animals were exposed to 5 Gy, 20 J/cm² of UV light, 200 ng/ml of LPS or 0.5 mM GSNO and the time-course of Ptpn1 mRNA levels was determined. (B) The protein levels of PTP1B were determined after 24 h of treatment by immunoblot. (C,D) The extent of apoptotic cells (48 h) and production of reactive oxygen species (24 h) were determined under these conditions. (E) The dose-dependent effect of γ-radiation (5 Gy and 10 Gy), UV exposure (20 and 40 J/cm²), LPS and GSNO on the GSH and GSSG levels were determined 24 h after exposure to these stressors. (F) Macrophages from WT (n = 3) or from PTP1B-deficient mice (n = 4) were isolated, incubated for 60 min with 5 mM N-acetyl-cysteine (NAC), 0.2 µM MnTBAP, 10 mM GSH or 0.1 µM ebselen and exposed to 5 Gy. After 48 h the percentage of apoptotic cells and the levels of GSH (G) were determined. Results show the mean of two experiments (A), a representative blot (B) and the mean±SD of three independent experiments (C-G), *P < 0.05; **P < 0.01; ***P < 0.005 vs. the same condition in WT cells or in the absence of challenge; ^aP < 0.05; ^aaP < 0.01; ^aaaP < 0.005 vs. the ‘none’ condition of WT cells.