Related Experiment Video
Updated: May 27, 2026
Measuring Single-Cell Aging with an Imaging-based Biomarker of Chromatin and Epigenetic Aging
Published on: January 30, 2026
Circulatory miR34a as an RNAbased, noninvasive biomarker for brain aging
Xiaoli Li1, Amit Khanna, Na Li
1Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Kentucky, USA.
Abstract:
MicroRNAs in blood samples have been identified as an important class of biomarkers, which can reflect physiological changes from cancer to brain dysfunction. In this report we identify concordant increases in levels of expression of miR-34a in brain and two components of mouse blood samples, peripheral blood mononuclear cells (PBMCs) and plasma, from 2 day old neonates through young adulthood and mid-life to old age at 25 months. Levels of this microRNA's prime target, silent information regulator 1 (SIRT1), in brain and the two blood-derived specimens decrease with age inversely to miR-34a, starting as early as 4 months old, when appreciable tissue aging has not yet begun. Our results suggest that: 1. Increased miR-34a and the reciprocal decrease of its target, SIRT1, in blood specimens are the accessible biomarkers for age-dependent changes in brain; and 2. these changes are predictors of impending decline in brain function, as early as in young adult mice.
Insights
Blood microRNAs like miR-34a are potential biomarkers for brain aging. Increased miR-34a and decreased SIRT1 in blood correlate with brain changes and predict cognitive decline.
Area of Science:
- Biochemistry
- Neuroscience
- Gerontology
Background:
- MicroRNAs in blood are key biomarkers for various physiological changes, including brain dysfunction.
- Identifying accessible biomarkers for brain aging is crucial for understanding cognitive decline.
Purpose of the Study:
- To investigate the relationship between miR-34a and its target SIRT1 in the brain and blood of mice across different age groups.
- To determine if miR-34a and SIRT1 levels in blood can serve as accessible biomarkers for age-dependent brain changes and predict cognitive function.
Main Methods:
- Quantification of miR-34a and SIRT1 expression levels in brain, peripheral blood mononuclear cells (PBMCs), and plasma of mice at various ages (neonatal to old age).
- Analysis of age-dependent expression trends and correlations between miR-34a, SIRT1, and age.
Main Results:
- Concordant increases in miR-34a expression were observed in the brain, PBMCs, and plasma from neonates to old age.
- Reciprocal decreases in SIRT1 levels were found in the brain, PBMCs, and plasma, inversely correlating with miR-34a, starting as early as 4 months.
- These age-related changes in blood specimens were evident even before significant tissue aging was apparent.
Conclusions:
- Increased miR-34a and decreased SIRT1 in blood samples are accessible biomarkers reflecting age-dependent brain changes.
- These blood-based biomarkers can predict impending declines in brain function, detectable as early as in young adult mice.
