T-31 Peptide Interactions with Cellular Aging, Renewal, and Stress Pathways

T-31 is posited to be a synthetic, three–amino acid research peptide consisting of the sequence Ala-Glu-Asp (AED), and is also sometimes referred to in the literature as Cartalax.  Structurally, it appears to belong to the family of so-called Khavinson’s short peptides. These are a group of oligopeptides that some investigators describe as peptide bioregulators on the basis that they may interact with chromatin and modulate the transcription of specific gene clusters.

The majority of published laboratory work suggests that T-31 may engage with selected DNA motifs and signaling proteins in cultured cells, and these interactions may shift the expression of cellular markers linked to proliferation, apoptosis, and senescence. Additional research posits that the peptide may have secondary actions on telomere-associated enzymes, growth factor transcripts, and inflammatory regulators in aging cells. Thus, current lab research implications may include using T-31 peptide as a tool to probe cellular age-associated transcriptional programs in renal epithelial cultures, fibroblasts, and mesenchymal stem cell models.

 

Research

T-31 Activity in Fibroblast Cultures

Work by Lin’kova et al. has examined the potential of T-31 on fibroblasts at different in vitro passage numbers. Fibroblasts are considered to be specialized connective-tissue cells that contribute to extracellular matrix synthesis, including collagens, fibronectin, and proteoglycans. Fibroblasts at different in vitro passage numbers are commonly used as a model of cellular aging.⁽¹⁾ The researchers posited that any peptide-induced shift in their proliferation or matrix-remodeling profile is potentially relevant to research on cellular aging and cell mass maintenance.

According to the research, Ki-67 expression in fibroblast cultures appeared to rise following T-31 exposure, which the authors interpret as a possible indication that the peptide may sustain proliferative capacity in this particular cell type. Specifically, Ki-67 is a nuclear protein generally considered in research settings as a proliferation-associated marker.

The investigators also observed an apparent upregulation of CD98hc, which is a heavy-chain glycoprotein involved in amino acid transport and integrin-linked signaling. Because CD98hc is implicated in nutrient handling and adhesion, its elevation might be compatible with conditions that support fibroblast viability during cellular aging.

Markers of programmed cell death also appeared to shift in this model. For example, caspase-3 is posited to act as an executioner caspase in the apoptotic cascade. Notably, its levels were suggested as being lower in both early- and late-passage fibroblasts exposed to T-31, leading the authors to state that the peptide “reduced the level of apoptosis in young and aged cell cultures.”

Alongside this, matrix metalloproteinase-9 (MMP-9) was apparently decreased in late-passage fibroblasts. Specifically, MMP-9 is considered to be a protease often linked to excessive extracellular matrix breakdown in aged tissue cells. The combined pattern of reduced caspase-3, reduced MMP-9, and elevated Ki-67 and CD98hc has been interpreted as data compatible with a potentially less catabolic, more renewal-oriented fibroblast phenotype in this research setting.

T-31 Affinity for Renal Epithelial Cell Cultures

Studies by researchers such as Khavinson et al. suggest that T-31’s main observable action in cultured renal epithelium may involve a coordinated shift in markers of cell renewal and apoptosis.⁽²⁾ In their work, primary kidney cell cultures aged in vitro were exposed to T-31 alongside a polypeptide complex isolated from calf kidney, and the expression of Ki-67, p53, MMP-14, and IL-8 was tracked by immunocytochemistry.

The researchers reported that T-31 apparently reduced the expression of the pro-apoptotic transcription factor p53 by roughly 1.33-fold in aged renal cell cultures, while the polypeptide complex produced a comparable 1.42-fold decrease. The researchers suggested that the peptide may lower the level of apoptosis in the aging cells of the renal epithelium by about 1.5 times and upregulate their proliferative capacity by roughly 2 times. This pattern suggests that, within this renal model, T-31 may primarily dampen pro-apoptotic signaling rather than directly drive proliferative markers.

Complementary observations by Chalisova et al. in kidney tissue cultures derived from young and old animals appear consistent with this interpretation, with T-31 exposure associated with apparent increases in Ki-67 signal and apparent decreases in p53 in aged renal cell cultures.⁽³⁾ Taken together, these reports may imply that the AED sequence is associated with a modest rebalancing of proliferation- and apoptosis-linked markers in renal epithelial models. However, the magnitude of each impact appears to vary by culture system and age of the donor tissue.

T-31 and Senescence-Associated Markers

Further work by Khavinson et al. in renal cell cultures suggests that T-31 may also support canonical senescence markers beyond p53.⁽⁴⁾ In these experiments, the peptide was associated with apparent reductions in the cyclin-dependent kinase mitigators p16 and p21, both of which are commonly used to define a senescent transcriptional state. Because p16 and p21 typically restrain cell cycle progression, their apparent downregulation under T-31 exposure may be compatible with a partial release of the senescence checkpoint in aged renal cell cultures.

In parallel, the authors reported an apparent increase in SIRT-6 transcript and protein levels. SIRT-6 is a chromatin-associated enzyme that has been posited to participate in DNA repair, telomeric chromatin maintenance, and metabolic regulation, and its decline has previously been associated with cellular senescence. Thus, an apparent T-31–linked increase in SIRT-6 may be interpreted as a potential counter-senescent signature within this research model.

Mechanistically, the same group of researchers posited that T-31 may form energetically favorable complexes with specific A/T-rich DNA motifs, particularly the d(ATATATATAT)₂ sequence. Such sequence-selective binding might in turn modulate local chromatin accessibility and the transcription of genes linked to aging cells. The structural details of these interactions remain uncertain. Still, the authors have used this DNA-binding hypothesis to frame T-31’s reported activity on p16, p21, p53, and SIRT-6 as a possible chromatin-level impact rather than a receptor-mediated one.

Additional research by Linkova et al. in a chondrogenic differentiation model suggests that T-31 may also alter the expression of TNKS2, the gene encoding tankyrase 2.⁽⁵⁾ Tankyrase 2 is considered to be involved in telomere maintenance through regulation of telomeric repeat-binding factors, and is additionally implicated in Wnt signaling and mitotic regulation.

In cellular aging or differentiation between cell cultures, an apparent modulation of TNKS2 by T-31 may, therefore, intersect with telomere stability, Wnt-dependent fate decisions, and broader metabolic adjustments. However, the precise direction and magnitude of the implication appear to depend on the specific cellular aging and passage protocol used.

T-31 and Cellular Stress Resistance

Research by Ashapkin et al. has examined T-31 peptide in embryonic bone marrow mesenchymal stem cell cultures (FetMSCs) aged either through serial passaging or under stationary, post-confluent conditions.⁽⁶⁾ Across both models, the peptide was evaluated alongside the related short peptides KED and KE for its impact on the IGF1, FOXO1, TERT, TNKS2, and NFκB transcripts. The authors suggested that IGF-1 transcripts were apparently elevated under T-31 exposure, commenting that “IGF1 gene expression levels were very similar in [different] cell culture aging models, being [better-supported] by 3.5-5.6 fold upon the addition of the peptides.”

IGF-1 is often described as a mediator of anabolic and reparative signaling, and its apparent induction in aged mesenchymal cell cultures may be interpreted as a possible adaptive response that may support synthetic activity during replicative or stationary stress. The consistency of this response across two structurally different aging cell models has been taken to imply that T-31’s interaction with IGF-1 may not depend strongly on a specific cellular aging trajectory.

The same study suggests that T-31 may be associated with reduced TERT (telomerase reverse transcriptase) transcripts in these mesenchymal cultures. TERT is the catalytic subunit of telomerase and is generally considered central to telomere length maintenance; some aged cell systems appear to upregulate TERT as part of a stress response. A T-31–linked decrease in TERT under these conditions may, therefore, be compatible with a shift toward a less reactive, possibly more stabilized transcriptional pattern. However, the functional consequences for telomere length in these particular cultures remain uncertain.

NFκB transcripts were also reported to rise under T-31 peptide, KED, and KE exposure in both the “passages” and “stationary” aging cellular models. NFκB is commonly considered a central regulator of inflammatory and stress-response gene programs, and various authors have interpreted its apparent upregulation in aging mesenchymal cell cultures as either a compensatory adaptive signal or a feature of the senescence-associated secretory phenotype.

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References:

1. Lin’kova NS, Drobintseva AO, Orlova OA, Kuznetsova EP, Polyakova VO, Kvetnoy IM, Khavinson VKh. Peptide Regulation of Skin Fibroblast Functions during Their Aging In Vitro. Bull Exp Biol Med. 2016 May;161(1):175-8. doi: 10.1007/s10517-016-3370-x. Epub 2016 Jun 4. PMID: 27259496.
2. Khavinson VKh, Lin’kova NS, Polyakova VO, Durnova AO, Nichik TE, Kvetnoi IM. Peptides regulate the expression of signaling molecules in kidney cell cultures during in vitro aging. Bull Exp Biol Med. 2014 Jun;157(2):261-4. doi: 10.1007/s10517-014-2540-y. Epub 2014 Jun 24. PMID: 24958378.
3. Chalisova NI, Lin’kova NS, Nichik TE, Ryzhak AP, Dudkov AV, Ryzhak GA. Peptide Regulation of Cells Renewal Processes in Kidney Tissue Cultures from Young and Old Animals. Bull Exp Biol Med. 2015 May;159(1):124-7. doi: 10.1007/s10517-015-2906-9. Epub 2015 Jun 2. PMID: 26033601.
4. Khavinson VKh, Tarnovskaia SI, Lin’kova NS, Poliakova VO, Durnova AO, Nichik TE, Kvetnoĭ IM, D’iakonov MM, Iakutseni PP. [Tripeptides slow down the aging process in renal cell culture]. Adv Gerontol. 2014;27(4):651-6. Russian. PMID: 25946838.
5. Linkova N, Khavinson V, Diatlova A, Myakisheva S, Ryzhak G. Peptide Regulation of Chondrogenic Stem Cell Differentiation. Int J Mol Sci. 2023 May 8;24(9):8415. doi: 10.3390/ijms24098415. PMID: 37176122; PMCID: PMC10179481.
6. Ashapkin V, Khavinson V, Shilovsky G, Linkova N, Vanuyshin B. Gene expression in human mesenchymal stem cell aging cultures: modulation by short peptides. Mol Biol Rep. 2020 Jun;47(6):4323-4329. Epub 2020 May 12. PMID: 32399807. https://doi.org/10.1007/s11033-020-05506-3