The Influence of KE and EW Dipeptides in the Composition of the Thymalin Drug on Gene Expression and Protein Synthesis Involved in the Pathogenesis of COVID-19. — VialBase Research

Summary

This paper sets out to identify the molecular mechanism behind Thymalin’s claimed immunomodulatory activity by studying its two active substances — the dipeptides KE and EW — rather than the polypeptide extract as a whole. The authors describe Thymalin as an immunomodulatory drug containing a polypeptide extract of thymus with reported efficacy in acute respiratory distress syndrome and chronic obstructive pulmonary disease and in complex therapy for severe COVID-19 in middle-aged and elderly patients, and note existing evidence that KE stimulates cellular immunity and nonspecific resistance (acting on macrophages, blood lymphocytes, thymocytes, and neutrophils) while EW reduces angiotensin-induced vasoconstriction and preserves endothelium-dependent vascular relaxation by inhibiting ACE2, the target protein of SARS-CoV-2. The work proceeds in two stages. First, computational: interactions between the dipeptides and double-stranded DNA were modelled by docking in ICM-Pro, and candidate gene and protein targets were assembled using the Eukaryotic Promoter Database, PathCards, STRING cluster analysis, and gene-ontology functional enrichment with the Markov cluster algorithm. Docking identified GGAG as the best dsDNA sequence for EW binding in the classical B-form and GCGC as the preferred sequence for KE in the curved nucleosomal form; cluster analysis pointed to AKT1 and AKT2 (both implicated in cytokine storm) as shared targets, with ACE2 and CYSLTR1 specific to EW and CHUK specific to KE. Second, wet-lab: in a lipopolysaccharide-induced inflammation model using human peripheral blood mononuclear cells, ELISA showed that Thymalin and the EW and KE dipeptides reduced IL-1beta, IL-6, and TNF-alpha by 1.4-6.0 times. The authors conclude that Thymalin’s immunomodulatory effect under inflammatory conditions in COVID-19 rests on the potential ability of EW and KE to regulate synthesis of proteins involved in cytokine storm. Notably, blood was obtained from only four donors.

Key Findings

• The study examines the isolated dipeptides KE and EW — described as Thymalin’s active substances — alongside the Thymalin preparation, so much of the mechanistic result is about the dipeptides rather than the commercial extract
• Molecular docking in ICM-Pro identified GGAG as the preferred double-stranded DNA sequence for EW in classical B-form, and GCGC as the preferred sequence for KE in curved nucleosomal form
• STRING cluster analysis identified AKT1 and AKT2 — proteins involved in cytokine storm — as potential targets of both peptides; ACE2 and CYSLTR1 emerged as EW-specific targets and CHUK as a KE-specific target, with protein products functionally associated with IL-1beta, IL-6, TNF-alpha, IL-4, and IL-10
• In an LPS-stimulated in-vitro model using human peripheral blood mononuclear cells, Thymalin and the EW and KE dipeptides reduced IL-1beta, IL-6, and TNF-alpha synthesis by 1.4-6.0 times
• Sample size for the wet-lab component was small and explicitly stated: blood from four donors, ELISA performed 2-4 times per cytokine, two parallel experimental or control samples per experiment, LPS-stimulated experiments repeated four times and unstimulated experiments twice

Relevance to Thymalin

This is the most technically detailed mechanistic paper in the Thymalin file and it is worth citing — but with two precise qualifications that vendors routinely drop. First, most of the molecular story here belongs to the isolated dipeptides KE and EW, not to the Thymalin thymus extract as sold; the paper’s own framing is that these dipeptides are the active substances within the drug, which means findings about GGAG/GCGC binding or ACE2 and CHUK targeting are statements about purified short peptides, not a validated account of what a vial of Thymalin does in a person. Second, the only experimental (as opposed to computational) evidence is a small in-vitro cytokine assay on peripheral blood mononuclear cells from four donors. A 1.4-6.0-fold reduction in IL-1beta, IL-6, and TNF-alpha in LPS-stimulated cell culture is a genuine anti-inflammatory signal in that system and nothing more; it does not establish clinical benefit in COVID-19, ARDS, or COPD. As with the rest of this literature, the work originates from the Khavinson group, so independent replication remains outstanding. Cite it for mechanism, never as outcome evidence.

Citation

Linkova N, Khavinson V, Diatlova A, et al. The Influence of KE and EW Dipeptides in the Composition of the Thymalin Drug on Gene Expression and Protein Synthesis Involved in the Pathogenesis of COVID-19. International journal of molecular sciences. 2023;24(17). doi:10.3390/ijms241713377.

See Also

• Parent compound: Thymalin