ABSTRACT
The overexpression and increased activity of the serine protease Kallikrein 5 (KLK5) is characteristic of inflammatory skin diseases such as Rosacea. The use of inhibitors of this enzyme-such as 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF·HCl) or the anti-human recombinant Kallikrein 5 (anti-KLK5) antibody-in the treatment of the disease has been limited due to their low bioavailability, for which their immobilization in drug delivery agents can contribute to making serine protease inhibitors clinically useful. In this work, we synthesized gold nanoparticles (GNP) coated with a mixture of hydroxyl- and carboxyl-terminated thiolates (GNP.OH/COOH), whose carboxyl groups were used to further functionalize the nanoparticles with the serine protease inhibitor AEBSF·HCl either electrostatically or covalently (GNP.COOH AEBSF and GNP.AEBSF, respectively), or with the anti-KLK5 antibody (GNP.antiKLK5). The synthesized and functionalized GNP were highly water-soluble, and they were extensively characterized using UV-vis absorption spectroscopy, Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), and Thermogravimetric Analysis (TGA). GNP.OH/COOH and their subsequent functionalizations effectively inhibited KLK5 in vitro. Internalization of fluorophore-coated GNP.OH/COOH in human keratinocytes (HaCaT cells) was proven using confocal fluorescence microscopy. Cell viability assays revealed that the cytotoxicity of free AEBSF is importantly decreased when it is incorporated in the nanoparticles, either ionically (GNP.COOH AEBSF) or, most importantly, covalently (GNP.AEBSF). The functionalized nanoparticles GNP.AEBSF and GNP.antiKLK5 inhibited intracellular KLK5 activity in HaCaT cells and diminished secretion of IL-8 under inflammatory conditions triggered by TLR-2 ligands. This study points to the great potential of these GNP as a new intracellular delivery strategy for both small drugs and antibodies in the treatment of skin diseases such as Rosacea.
Subject(s)
Gold/chemistry , Metal Nanoparticles/chemistry , Rosacea/therapy , Serine Proteinase Inhibitors/therapeutic use , Antibodies/immunology , Cells, Cultured , Humans , Interleukin-8/metabolism , Kallikreins/immunology , Microscopy, Electron, Transmission , Microscopy, Fluorescence , Rosacea/metabolism , Serine Proteinase Inhibitors/chemistry , Solubility , Spectrophotometry, Ultraviolet , Sulfones/therapeutic use , ThermogravimetryABSTRACT
The effects of oral administration of the antihistamine cetirizine on the weal and flare caused by intradermal injection of platelet activating factor (PAF-acether), kallikrein, histamine and the patient's own serum were investigated in 10 patients with chronic urticaria. Cetirizine markedly reduced the weal and flare induced by all these agents as measured 12 min after the injections. The delayed reactions observed after injection of PAF, kallikrein and serum were also inhibited by cetirizine at 6 hours. In addition, reactions which were present 20 h after injection of the agent before administration of cetirizine were found to be inhibited at the same point in time after cetirizine treatment. These effects might explain the good inhibitory clinical effect of cetirizine on the patients' urticaria. No side-effects were noted during the treatment.