Open AccessCharacterization of the role of distinct plasma cell‐free DNA species in age‐associated inflammation and frailty
Author(s) -
Jylhävä Juulia,
Nevalainen Tapio,
Marttila Saara,
Jylhä Marja,
Hervonen Antti,
Hurme Mikko
Publication year - 2013
Publication title -
aging cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.103
H-Index - 140
eISSN - 1474-9726
pISSN - 1474-9718
DOI - 10.1111/acel.12058
Subject(s) - biology , immunosenescence , inflammation , dna , microbiology and biotechnology , dna damage , immunology , transcriptome , gene , genetics , gene expression , immune system
Summary Plasma cell‐free DNA (cf‐ DNA ) has recently emerged as a potential biomarker of aging, reflecting systemic inflammation, and cell death. In addition, it has been suggested that cf‐ DNA could promote autoinflammation. Because the total cf‐ DNA pool comprises different cf‐ DNA species, we quantified the plasma levels of gene‐coding cf‐ DNA , Alu repeat cf‐ DNA , mitochondrial DNA (mt DNA ) copy number, and the amounts of unmethylated and total cf‐ DNA s. We identified the relationships between these cf‐ DNA species and age‐associated inflammation, immunosenescence, and frailty. Additionally, we determined the cf‐ DNA species‐specific transcriptomic signatures in blood mononuclear cells to elucidate the age‐linked leukocyte responses to cf‐ DNA . The study population consisted of n = 144 nonagenarian participants of the Vitality 90+ Study and n = 30 young controls. In the nonagenarians, higher levels of total and unmethylated cf‐ DNA s were associated with systemic inflammation and increased frailty. The mt DNA copy number was also directly correlated with increased frailty but not with inflammation. None of the cf‐ DNA species were associated with immunosenescence. The transcriptomic pathway analysis revealed that higher levels of total and unmethylated cf‐ DNA s were associated with immunoinflammatory activation in the nonagenarians but not in the young controls. The plasma mt DNA appeared to be inert in terms of inflammatory activation in both the nonagenarians and young controls. These data demonstrate that the plasma levels of total and unmethylated cf‐ DNA and the mt DNA copy number could serve as biomarkers of frailty. In addition, we suggest that circulating self‐ DNA , assessed as total or unmethylated cf‐ DNA , might aggravate immunoinflammatory reactivity in very old individuals.