Genetic Mechanisms of Age Regulation of Protein C and Blood Coagulation

Abstract

Blood coagulation activity in humans increases with age. We previously identified two genetic elements, agerelated stability element (ASE; GAGGAAG) and age-related increase element (AIE; unique stretch of dinucleotide repeats), which were responsible for age-related stable and increasing expression patterns, respectively, and together recapitulated normal age regulation of the human factor IX (hFIX) gene. Here we report the ageregulatory mechanisms of human anticoagulant protein C (hPC), which shows an age-stable pattern of circulatory levels. The murine protein C gene showed an agerelated stable expression pattern in general agreement with that of the hPC. Through longitudinal analyses of transgenic mice carrying hPC minigenes, the hPC gene was found to have a functional age-related stability element (hPC ASE; CAGGAAG) in the 5-upstream proximal region but was found to lack any age-related increase element. Three other ASE-like sequences present in the hPC gene, GAGGAAA and (G/C)AGGATG, also bound nuclear proteins but were not active in the age regulation of the hPC gene. Functional hPC ASE and hFIX ASE were apparently generated through convergent evolution, and hFIX ASE can fully substitute for the hPC ASE in conferring age-related stable expression pattern of the hPC gene. In the presence of the hPC ASE, hFIX AIE can convert the age-stable expression pattern of the hPC gene to a hFIX-like age-related increase pattern. These results support the universality of ASE and AIE functions across different genes. Clearance of hPC protein from the circulation was not significantly affected by age. We now have established the basic mechanisms responsible for the age-related increase of blood coagulation activity.

An age-related homeostasis mechanism is essential for spontaneous amelioration of hemophilia B Leyden

“…2B). Oligonucleotide probes with core heptamer sequences of the functional ASEs, G/CAGGAAG, bind an identical mouse liver nuclear protein (1,2). Similar to the ASEs, but subtly different heptamer sequences, GAGGAAA and GAGGATG, which do not function as ASEs (2) (see Table S1), also bound liver nuclear proteins (Table S2).…”

“…Transgenic mice were constructed according to the standard methods (33) at the Bio-medical Research Animal Model Core facility at the University of Michigan as previously described (1,2). Serum hFIX concentrations of mice were determined by duplicated hFIX-specific ELISA, and average values were plotted.…”

“…lthough the importance of aging on human health is well known, only recently has the first specific molecular mechanism for age-related gene regulation been discovered (1)(2)(3). This mechanism, the age-related stability element (ASE)/agerelated increase element (AIE)-mediated genetic mechanism for age-related gene regulation, was originally discovered through extensive studies of transgenic mice carrying minigenes of human blood coagulation factor IX (hFIX) (1) and antiblood coagulation factor protein C (hPC) (2).…”

“…This mechanism, the age-related stability element (ASE)/agerelated increase element (AIE)-mediated genetic mechanism for age-related gene regulation, was originally discovered through extensive studies of transgenic mice carrying minigenes of human blood coagulation factor IX (hFIX) (1) and antiblood coagulation factor protein C (hPC) (2). In this mechanism, 2 genetic elements, ASE and AIE , play critical roles in generating patterns of stable puberty-onset gene expression and age-related increases in gene expression, respectively.…”

“…For competitive EMSA, probes without 32 P-lableing were used (2). Preparative EMSAs were carried out with larger amounts of liver NEs (160 g aliquots) with 120,000 cpm of 32 P-labeled oligonucleotide probe using 18 ϫ 18 cm electrophoresis glass plates.…”