Anti-Inflammatory Activity of a Cyclic Tetrapeptide in Mouse and Human Experimental Models.

Janusz Zabrocki,Michał Zimecki,Jan Kuryszko,Wojciech Kałas,Andrzej Kaszuba,Krzysztof Kaczmarek,Katarzyna Kaleta-Kuratewicz,Jolanta Artym,Leon Strządała

doi:10.3390/pharmaceutics12111030

Abstract

A cyclic tetrapeptide Pro-Pro-Pheβ3ho-Phe (4B8M) was tested for immunosuppressive activity and potential therapeutic utility in several in vitro and in vivo mouse and human models. The tetrapeptide was less toxic for mouse splenocytes in comparison to cyclosporine A (CsA) and a parent cyclolinopeptide (CLA). The tetrapeptide demonstrated potent anti-inflammatory properties in antigen-specific skin inflammatory reactions to oxazolone and toluene diisocyanate as well to nonspecific irritants such as salicylic acid. It also inhibited inflammatory processes in an air pouch induced by carrageenan. In addition, 4B8M proved effective in amelioration of animal models corresponding to human diseases, such as nonspecific colon inflammation induced by dextran sulfate and allergic pleurisy induced by ovalbumin (OVA) in sensitized mice. The tetrapeptide lowered expression of EP1 and EP3 but not EP2 and EP4 prostaglandin E2 (PGE2) receptors on lipopolysaccharide-stimulated Jurkat T cells and ICAM-1 expression on human peripheral blood mononuclear cells (PBMC). Its anti-inflammatory property in the carrageenan reaction was blocked by EP3 and EP4 antagonists. In addition, 4B8M induced an intracellular level of PGE2 in a human KERTr keratinocyte cell line. In conclusion, 4B8M is a low toxic and effective inhibitor of inflammatory disorders with potential therapeutic use, affecting the metabolism of prostanoid family molecules.

Highlights

Immunosuppressive drugs, such as cyclosporine A (CsA), tacrolimus, and rapamycin, demonstrate undesirable side-effects upon prolonged application [1]
Cyclosporin A (CsA) (Sandimmun, Neoral, Sandoz, Basel, Switzerland) in ampoules, RPMI-1640 medium (Cibi/Life Technologies, Inchinnan, UK), fetal calf serum (FCS), serum-free keratinocyte medium, bovine pituitary extract derived from Gibco Thermo Fisher Scientific (Waltham, MA, USA), glutamate, HEPES, sodium pyruvate, antibiotic and antimycotic solution, cyclolinopeptide (CLA), lipopolysaccharide (LPS) from Escherichia coli 0:111, concanavalin A (Con A), phytohemagglutinin A (PHA), ovalbumin (OVA), indomethacin, aspirin, MTT (93-[4-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide), oxazolone, salicylic acid, toluene diisocyanate (TDI), recombinant Epidermal Growth Factor (EGF), carrageenan (C-1013, Lot 102 K0871), AH23848 (A8227, Lot 090M4618V) (EP4 receptor antagonist), L-798106 (L4545, Lot 020M4617V) (EP3 receptor antagonist), Giemsa and May-Grünwald reagents, hematoxylin, eosin, and toluidine blue were derived from Sigma-Aldrich
The 4B8M peptide was tested for its immunosuppressive activity and potential therapeutic utility in a number of in vitro and in vivo mouse models

Summary

Introduction

Immunosuppressive drugs, such as cyclosporine A (CsA), tacrolimus, and rapamycin, demonstrate undesirable side-effects upon prolonged application [1]. Synthesis of new analogs of CLA aimed to improve their bioaccessibility and activity led to the following conclusions. Linear CLA analogs, bearing alanine residue in successive positions of the peptide chain, demonstrated suppressive activities [6]. An improvement in solubility could be achieved by introducing a sulfonic group in the “para” position of the aromatic ring of one or two phenyloalanine residues without loss of biological activity [8,9]. Pro-Pro-Phe-Phe or Pro-Phe-Phe CLA fragments seemed to be responsible for the immunosuppressive activity [10,11]. It could be concluded that the Pro-Pro-Phe-Phe fragment was crucial for the biological activity of CLA [12]

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