Figure 5. Aging human LECs/lenses showed age-dependent decline in Senp1 expression and increased Sumo1 expression, which were directly related to increase Sp1 Sumoylation. (A) Aging hLECs/lenses displayed a progressive decline in the deSumoylating agent Senp1 and an increase in Sumo1 levels. Total RNA was isolated from human lenses/LECs of different ages as indicated, and was processed for real-time qPCR analysis as stated in Materials and Methods. The data represent the mean ± S.D. values from three independent experiments. P values were determined for younger (18y) vs aging samples. **p<0.05, *p < 0.001. (B) Nuclear lysates were prepared from hLECs/lenses of various ages and were submitted to Sp1 sandwich/Sumo1-ELISA to examine the total and Sumoylated Sp1 protein. Primary hLECs isolated from lenses of different ages were divided into four groups: 16-18y (n=6); 52-58y (n=8); 62-66 (n=8); and 74-76y (n=8). Sumoylated Sp1 protein was subtracted from total Sp1 protein, and presented as deSumoylated (B, gray bars) and Sumoylated (B, black bars) forms of Sp1. Data represent mean ± SD from two independent experiments. p values were determined for younger (16-18y) vs aging samples. *p < 0.001.