Figure 11.

Type I collagen transcriptional activities and type I and type IV collagen expression in mesangial cells. A: Increased type I collagen transcriptional activity in mesangial cells isolated from 28-month-old mouse (28-month MC). Basal and TGF-β1-mediated activation of type I collagen transcription was assessed in mesangial cells transfected with 250 ng of a type I collagen promoter reporter construct and 250 ng of a Rous sarcoma virus β-galactosidase plasmid in the presence or absence of 2 ng/ml TGF-β1. (**, P < 0.01 vs. cells isolated from a 5-month-old mouse (5-month MC); #, P < 0.05, ##, P < 0.01 vs. basal activities). B: Increased α1 (I) collagen mRNA expression in mesangial cells isolated from 28-month-old mouse. α1 (I) collagen and GAPDH mRNA levels were measured by competitive PCR using total RNA isolated from mesangial cells. Results are expressed as the ratio of α1 (I) collagen to GAPDH mRNA. Mesangial cells from 28-month-old mouse had higher α1 (I) collagen mRNA levels as shown by competitive PCR. cDNAs from mesangial cells cultured from 5-month and 28-month-old mice were amplified with decreasing amounts of competing mutant (from left to right: 0.1−0.00125 attomol). C: α1 (I) collagen mRNA levels were increased in mesangial cells isolated from 28-month-old mouse. (**, P < 0.01 vs. cells isolated from a 5-month-old mouse). D: Increased type I collagen in mesangial cells isolated from 28-month-old mouse. The amount of type I collagen produced by mesangial cells was determined by ELISA and corrected by the cell number. (**, P < 0.01 vs. cells isolated from 5-month-old mouse). E: Increased α1 (IV) collagen mRNA expression in mesangial cells isolated from 28-month-old mouse. α1 (IV) collagen mRNA levels were measured by real-time PCR and corrected by the GAPDH mRNA levels. The value obtained from mesangial cells isolated from 5-month-old mouse was arbitrarily defined as 100%.