Preliminary Evidence for Increased Histone Succinylation as a Potential Epigenetic Marker for Longevity

Abstract

Histone post-translational modifications (PTMs) are critical regulators of chromatin structure and gene expression, with broad implications for development, metabolism, and aging. While canonical modifications such as methylation and acetylation are well characterized, the role of histone succinylation remains poorly understood. Here, we investigated histone succinylation in the context of aging and exceptional longevity. Using mass spectrometry-based proteomics, we quantified histone succinylation in B-cells from four groups: young individuals, older individuals without parental longevity (OPUS), long-lived individuals, and offspring of long-lived individuals (OPEL). We found that histone succinylation was significantly elevated in the OPEL group compared to both young and OPUS cohorts. Nuclear proteomics further revealed enrichment of succinylated proteins in OPEL samples, supporting a role for succinylation in chromatin organization. To test whether succinate availability impacts healthspan, we supplemented middle-aged mice with succinic acid. While body weight, frailty index, and cognition were unaffected, succinic acid improved motor coordination and muscle strength. Together, our findings provide preliminary evidence that enhanced histone succinylation may serve as a protective epigenetic mechanism in individuals predisposed to exceptional longevity, and that succinate supplementation can selectively improve aspects of physical performance during aging.

Keywords: aging; chromatin modifications; epigenetics; healthspan; histone succinylation; longevity; progeny of long‐lived individuals.

FIGURE 1

Histone succinylation in aged groups. (a) Workflow. B‐cells are purified from four groups of donors, namely young individuals (20s), older individuals (OPUS, 70s), the progeny of long‐lived individuals (OPEL, 70s), and long‐lived individuals (95 and older). (b) Quantification of global histone succinylation (left), methylation (center) and acetylation (right) using mass spectrometry. The relative abundance is calculated by summing the intensities of all peptides identified with the given modification vs. all peptide intensities. (c) Extracted ion chromatograms of the peptide containing H3K23succinyl to manually validate the detection in mass spectrometry of succinylated peptides. (d) Gene Ontology enrichment of proteins quantified via mass spectrometry from the nuclear proteome of the OPEL versus the OPUS group. Functional annotation was obtained using GOrilla (Eden et al. 2009). (e) Quantification of total levels of H3K9me3 (left) and H3K27me3 (right) with mass spectrometry. The relative abundance was obtained by summing all peptides containing the given modification versus the intensity of all (un)modified peptides sharing the same sequence. (f) Volcano plot displaying the quantified peptides in long‐lived individuals vs. young group. Highlighted are the two peptides quantified to be modified with H3K9me3.

FIGURE 2

Effects of succinylation. (a) Gene Ontology enrichment of proteins quantified via mass spectrometry from the nuclear proteome of the long‐lived individuals hvs the young group. (b) Protein–protein interaction network of upregulated proteins in the soluble nuclear fraction of long‐lived individuals. Size of nodes represents p‐value, color darkness represents the score (fold change enrichment times the p‐value), and line thickness represents the score of interaction confidence retrieved from the software String. The network was constructed by Cytoscape (Shannon et al. 2003). (c) Body weight measured over 8 weeks. (d) Frailty index (general age‐related health deficits). (e) Box maze performance. (f) Balance beam performance on easy (left), medium (center) and hard (right) beams. (g) Grip strength test (20 g weight). Data are shown as mean ± SD.