Aggregate expression of genes lacking CpG islands increases with age and is positively associated with human mortality
[article]
Richard A. Kerber, Elizabeth O'Brien, Richard M. Cawthon
2022
medRxiv
pre-print
In both mice and humans the misexpression of many genes lacking CpG islands (CGI- genes) increases with age, promoting inflammation and degenerative changes (Lee et al. 2021, ref. 1). In light of this recent discovery, we have revisited and expanded upon our previous work on gene expressions vs. aging and mortality in the three-generation CEPH (Centre d'Etudes du Polymorphisme Humain) Utah (CEU) families (Kerber et al. 2009, ref. 2). That study examined gene expressions in lymphoblastoid cell
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... nes (LCLs) established in the early 1980s from all three CEU generations, in relation to age at blood draw, and in relation to the long-term survival of the grandparent generation. The 2009 study did not, however, consider the CGI status of genes, and it excluded from analysis genes not expressed in all of the subjects; therefore, the contribution to variation in age-at-death of inter-individual variation in the misexpression of genes with increasing age was not investigated. For the current study, after categorizing genes by their CGI status (- or +), we now find that most CGI- gene expressions in the LCLs increased with donor age, and after adjustment for donor age and sex, were positively associated with mortality risks. In contrast, most CGI+ gene expressions decreased with donor age, with higher expressions associated with decreased mortality risks. Of 7025 genes with known CGI status with expression detected in sufficient numbers of subjects from the grandparent generation to allow testing of association with mortality, 1834 genes were expressed in all subjects' LCLs across all three generations, and 5191 were expressed in some, but not all subjects. We found the set of "not always expressed" genes to be highly enriched for CGI- genes. Furthermore, 49.4% of the CGI- genes were never expressed from ages 0-14, but expressed sometimes or always at older ages; in contrast, only 22.3% of the CGI+ genes were never expressed from ages 0-14, but expressed at older ages. These data support the model proposed by Lee et al. 2021, whereby tissue-restricted CGI- gene expressions become increasingly misexpressed during aging, contributing to loss of cellular identity, multiple aging-related pathologies, and ultimately death.
doi:10.1101/2022.09.03.22279290
fatcat:hcua5zi72vbx7f5ui7pr5gc6ka