Developing a novel recombinant IL-1 receptor antagonist to treat the cytokine storm in Covid-19

One of the deadliest symptoms of Covid-19 is the development of acute respiratory distress syndrome (ARDS) in the patients. The hyperactivation of immune system due to SARS-CoV-2 infection results in the sudden release of numerous cytokines including interleukins which is called cytokine storm. Interleukin-1β (IL-1β) is known as one of the most important cytokines playing a role in the emergence of this phenomenon in inflammatory diseases. Therefore, blocking the pathway induced by IL-1β has been considered a promising treatment approach in the presence of cytokine storm. Endogenous interleukin-1 receptor antagonist (IL-1Ra) binds to the same receptor as IL-1β and inhibits the pathway. The commercially available recombinant version of IL-1Ra, anakinra, has already been used in the treatment of autoinflammatory diseases such as rheumatoid arthritis (RA), type II diabetes, and familial Mediterranean fever (FMF) since 2001 in order to alleviate the inflammatory response. Therefore, it has been used on Covid-19 patients in clinical trials and shown to be a potential medication due to its role in the attenuation of the cytokine storm. In the first part of this thesis, in vitro characterization of two novel recombinant IL-1Ra proteins was performed. The recombinant proteins were produced by Dr. Cem Albayrak's and Dr. Serdar Uysal's group as local alternatives to anakinra, which is not commercially available in Turkey. In this part of the thesis, the bioactivity of the recombinant proteins and their effects on cell viability were investigated. In order to assess the bioactivity of the proteins, genetically modified HEK-Blue cells were used to determine the impact of the proteins in IL-1β-induced SEAP production using QUANTI-Blue agent to measure, and IC50 value was calculated. Also, the ability of IL-1Ra-His6 protein to inhibit IL-1β-induced IL-6 production in MRC-5 lung fibroblasts was evaluated via ELISA. Finally, the viability of HEK293T and MRC-5 cells were inquired using CTG assay. Chitosan is one of the most promising biomaterials due to its unique properties such as biocompatibility, biodegradability, mucoadhesivity, and low immunogenicity. These properties make chitosan an excellent candidate for various biomedical applications such as wound healing, tissue engineering, and gene/drug delivery. Using chitosan in nanoparticle-based delivery systems increases its potential even further, primarily enabling the delivery of a high amount of genetic material. In the second part of the thesis, transfection and permeation enhancing capabilities of TRAIL encapsulated PEGylated chitosan nanoparticles were investigated. 5 kDa PEG was used to PEGylate chitosan to improve its physicochemical properties. Nanoparticles were synthesized using a crosslinking agent (TPP) and PEGylated chitosan derivative. In order to encapsulate tumor necrosis factor (TNF) α-related apoptosis-inducing ligand (TRAIL) inserted plasmid DNA was added in the process of crosslinking. Synthesized nanoparticles were characterized using scanning electron microscopy (SEM). Also, TRAIL encapsulated nanoparticles were incubated with 3 different glioblastoma (GBM) cell lines (A172, LN18, T98G), and transfection efficiencies of nanoparticles were experimentally investigated using flow cytometry. For the assessment of permeation enhancing capability of nanoparticles, Calu-3 cells were used, and the change in the transepithelial electrical resistance (TEER) was measured.