Tier 4 — mechanistic

AKG-TET axis is central to senescence plasticity

Akakura S, Tabibzadeh S
iScience 2025 29(1):114298

Bibliography

PubMed
PMID 41497192
PubMed Central
PMC12767804
DOI
10.1016/j.isci.2025.114298
Funding
Funded by a nonprofit research organisation (grant number not disclosed in the published article). The senior author is affiliated with the Frontiers in Bioscience Research Institute in Aging and Cancer, which supported the work.
Competing interests
A utility provisional patent application (US 63/635,888) covering the TET-targeting peptides used in this study was filed with a priority date of 24 April 2024. The authors declare no other competing financial or non-financial interests.

Study snapshot

DesignMechanistic in-vitro study (siRNA knockdown, pharmacological inhibition, and peptide modulation of AKG bioavailability and TET enzyme activity)
ModelHuman adult and neonatal dermal fibroblasts (aHDF, nHDF) and peripheral blood mononuclear cells (PBMCs) from adult volunteers aged 25–100
SampleCell-culture study; PBMC donors ranged in age from 25 to 100 years (exact donor count not reported in the abstract/results text extracted)
InterventionAKG-TET axis activity was lowered (TET1 siRNA, the TET inhibitor C35, or the AKG-limiting peptide RLS) or raised (the AKG-enhancing peptide CLV, or CRISPR-activated TET1 overexpression) and downstream effects on senescence markers were measured
Duration7-day treatment protocols, with a 7-day withdrawal/recovery arm to test reversibility
EndpointsDNA methylation marks (5mC, 5hmC, 5fC); SASP factors and NF-κB pro-inflammatory signalling (IL-6, IL-8); Oxidative stress and DNA damage (ROS, 8-OHdG, γH2AX); Cell-cycle arrest and proliferation (BrdU incorporation, SA-β-Gal activity); Reversibility of senescence markers after treatment withdrawal

What the study showed, in plain terms

This 2025 laboratory study asked a basic question: is cellular senescence — the state where aged cells stop dividing and start leaking inflammatory signals — always a one-way street, or can it be dialled up and down?

The researchers focused on alpha-ketoglutarate (AKG) and a family of enzymes called TET, which use AKG as a fuel to keep DNA methylation patterns in good order. When they starved human skin cells and blood cells of AKG or blocked TET activity, the cells developed the full hallmark picture of senescence: DNA damage, chronic inflammatory signalling, and permanent growth arrest.

The reverse also held. Restoring AKG availability, or boosting TET activity, protected cells against damage-induced senescence — and, more strikingly, partially reversed senescence that had already set in, restoring the cells' ability to divide again.

This paper matters to the Ca-AKG conversation because it is a mechanistic account of why AKG has been linked to ageing biology in the first place — it directly ties AKG availability to the molecular machinery that decides whether a cell ages gracefully or turns senescent. It is laboratory, cell-based evidence, not evidence that a Ca-AKG capsule changes senescence in a living person.

Key findings

  • AKG-TET deficiency induces senescence: reducing AKG bioavailability or TET1 expression in human fibroblasts and PBMCs reproduced the hallmark features of senescence — elevated 5-methylcytosine, reduced 5-hydroxymethylcytosine, increased reactive oxygen species and 8-OHdG DNA damage, NF-κB activation, IL-6/IL-8 secretion, and cell-cycle arrest.
  • Raising AKG-TET activity protects against damage: pretreatment with an AKG-enhancing peptide (CLV) or CRISPR-driven TET1 overexpression prevented hydrogen-peroxide-induced senescence and preserved proliferative capacity.
  • Senescence was partially reversible: withdrawing the AKG-TET-suppressing treatments, or actively boosting AKG-TET activity in already-senescent cells, normalised methylation marks, reduced inflammatory secretion, and restored BrdU-measured proliferation — in both replicatively senescent fibroblasts and aged donor PBMCs.
  • Specificity was controlled for: scrambled and irrelevant control peptides did not reproduce the effects, and a distinct TET3-targeting peptide (RIS) behaved differently from the TET1-targeting peptide (RLS), arguing against generic peptide toxicity.

What this study can and cannot tell us

Cell-culture study only. No animal model and no human supplementation arm. The paper establishes a mechanism linking AKG availability to TET enzyme activity and senescence markers — it does not test whether oral Ca-AKG raises intracellular AKG enough in vivo to move this axis.

Peptide tools, not the supplement. The AKG-raising and AKG-lowering interventions used engineered TET-domain peptides and genetic tools, not dietary or supplemental AKG. Translating this to "a Ca-AKG capsule reverses senescence" is not supported by this paper.

Declared competing interest. A provisional patent application covers the TET-targeting peptides used in the study, which is a relevant commercial interest to weigh alongside the findings.

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Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction Dr. Amr Yasser, PhDCardiometabolic, Musculoskeletal, Gut & Bioavailability Dr. Abdulla Mostafa, PhDCellular Senescence, Neurological, Mitochondrial & Brain-Ageing Biology