Cortagen

Cortagen (Ala-Glu-Asp-Leu) is one of a family of synthetic short peptides developed within the Khavinson peptide-bioregulator research program at the St. Petersburg Institute of Bioregulation and Gerontology, which produced defined-sequence peptides by directed synthesis modeled on motifs identified in tissue peptide extracts. The AEDL sequence and its synthetic characterization — molecular formula C18H30N4O9; molecular weight 446.45 g/mol; documented as an acetate salt at approximately 98% HPLC peptide content — are recorded in US Patent 7,625,870 (Khavinson et al., 2009). The framework positing that short peptides of 2–7 residues may penetrate cells, enter the nucleus, and interact with DNA to associate with gene-expression changes is reviewed by Vanyushin & Khavinson (2016) and examined across the class in the systematic review by Khavinson et al. (2021). This literature originates overwhelmingly from a single research group and affiliated laboratories, and independent replication of the core DNA-interaction mechanism outside this group has not been identified.

The most sequence-specific applied work places Cortagen in bronchial and pulmonary cell and tissue models. Khavinson et al. (2014, Lung) characterized Ki67, Mcl-1, p53, CD79, and NOS-3 protein levels across serial passages of human embryonic bronchoepithelial cell cultures alongside expression profiling of bronchial-differentiation factors NKX2-1, SCGB1A1, SCGB3A2, FOXA1, and FOXA2 and mucin/surfactant genes MUC4, MUC5AC, and SFTPA1; the study also included spectrophotometric, viscometric, and circular-dichroism examination of the peptide–DNA interaction. Khavinson et al. (2012, Bulletin of Experimental Biology and Medicine) examined differentiation-factor transcripts including CXCL12 and Hoxa3 in serially passaged human bronchial epithelial cultures — used as an in vitro model of replicative senescence — applying the AEDL tetrapeptide as the tissue-matched peptide alongside non-matched short peptides as controls. In a rodent preclinical system, Kuzubova et al. (2015) used a 60-day intermittent nitrogen dioxide–exposure protocol in rats as a model of obstructive lung pathology and assessed bronchial-epithelial morphology endpoints — goblet-cell hyperplasia, squamous metaplasia, and ciliated-cell status — and secretory immunoglobulin A as a mucosal marker.

A separate strand of biophysical work characterizes AEDL–nucleic acid and AEDL–chromatin interactions in isolation. Monaselidze et al. (2011, Bulletin of Experimental Biology and Medicine) applied differential scanning microcalorimetry to measure DNA melting thermodynamics across a range of peptide-to-DNA base-pair molar ratios, examining interactions with calf thymus and mouse liver DNA. Morozova et al. (2017, Journal of Structural Chemistry) employed UV spectrophotometry, circular dichroism, and viscometry to characterize complex formation in solution at varying ionic strength and reported binding at the guanine N7 position in the major groove without visible duplex distortion. Fedoreyeva, Vanyushin & Baranova (2020, AIMS Biophysics) examined chromatin-conformation changes associated with AEDL exposure, reporting binding to linker histone H1 and core histone H3 and associated remodeling of condensed-chromatin domains. Nuclear penetration of fluorescently labeled short peptides in the Khavinson class was examined in HeLa cell cultures by Fedoreyeva et al. (2011, Biochemistry (Moscow)) as a mechanistic entry point for the proposed nucleus-targeting model. Docking-based modeling (Khavinson, Lin'kova & Tarnovskaya, 2016) associates the AEDL and EDL sequences with a CTCC promoter tetranucleotide binding site.

The proposed DNA-interaction mechanism has been examined in plant model systems as part of a broader argument for cross-kingdom conservation. Lazareva et al. (2025, International Journal of Molecular Sciences) characterized metabolism and autophagy markers — including the autophagy marker ATG8, cytochrome c release, and TUNEL-detected DNA strand breaks — in root cells of Nicotiana tabacum exposed to the AEDL tetrapeptide. An earlier study by Fedoreyeva et al. (2017, Biochemistry (Moscow)) examined AEDL alongside related short peptides for associations with expression of CLE, KNOX1, and GRF gene families in the same plant model system. These comparative studies are cited by the originating research group as supporting a conserved peptide–DNA interaction mechanism; they do not independently establish relevance in mammalian or human systems.