Figure 7.

CHOP^−/− proximal tubular cells, CHOP^−/− diabetic mice, and CHOP^−/− aging mice. A: CHOP^−/− proximal tubular cells were relatively resistant to ER stress-induced cell death. Proximal tubular cells from wild-type and CHOP^−/− mice were treated with increasing concentration of tunicamycin (Tuni; 0.6–1.2 μg/ml) for 24 hours. The percentage of cell death was quantitated. **P < 0.01 versus CHOP^−/− cells at the same dosage. B: CHOP^−/− and wild-type mice were made diabetic by streptozotocin, and mice were followed for 4 months. Urine albumin excretion was elevated in wild-type diabetic mice but not in CHOP^−/− diabetic mice. **P < 0.01 versus CHOP^−/− diabetic mice. Con, control. C: Moderate expansion of the mesangial area is present in wild-type diabetic mice, whereas CHOP^−/− diabetic glomeruli are nearly normal (D) (PAS ×200). E: Urine albumin excretion was increased in wild-type (WT) but not in CHOP^−/− 20-month-old male mice. **P < 0.01. F: SDS-polyacrylamide gel electrophoresis analysis of urine samples from young (4-month-old wild-type and CHOP^−/−) and old (20-month-old wild-type and CHOP^−/−) male mice. Note an increase in protein (Pro) at approximately 72 kDa in two old wild-type mice.