Recombinant Production and One-Step Purification of IL-1Ra in Escherichia coli and Evaluation of its IL-1 Antagonizing Efficacy.

BACKGROUND: Anakinra (Kineret®), an IL-1 receptor antagonist, is the first FDA-approved biologic drug for antagonizing IL-1 in patients with Rheumatoid arthritis. The less expensive production of this drug might help reduce the final therapeutic costs. OBJECTIVES: To evaluate the possibility of producing biologically active recombinant IL-1Ra by a single-step purification procedure mediated by a self-cleavable intein. METHODS: Soluble expression of the rIL-1Ra was performed in E. coli BL21 (DE3) infusion to intein1 of pTWIN-1 vector and its cleavage induction using an elution buffer (pH 6.8) at room temperature. Evaluation of the antagonizing efficacy of this protein in various concentrations was performed on A375 and HEK293 cells treated by a constant concentration of IL-1ß (2 ng/mL). RESULTS: IPTG induction of E. coli BL21 (DE3) transformed with the recombinant pTWIN-1, revealed a band approximately in 45 kDa, which is related to the intein1-rIL-1Ra fusion protein in the SDS-PAGE. Moreover, protein purification was confirmed by observing a band in 18 kDa. Finally, the percentage of inhibition effects of rIL-1Ra and Kineret® against IL-1ß was not statistically significant in IL-1-responsive A375 cells. The inhibition percentage was calculated as 86% in cells treated with 15µg/mL of rIL-1Ra, which was 96% for the inhibitory effects of the standard drug. CONCLUSION: In this study, biologically active soluble rIL1-Ra was successfully produced with high purity through a one-step procedure. This method can reduce the cost and time of production for this protein and might be applicable other biological products.

Minimally-invasive Sampling of Interleukin-1α and Interleukin-1 Receptor Antagonist from the Skin: A Systematic Review of In vivo Studies in Humans.

Interleukin-1α (IL-1α) and its receptor antagonist IL-1RA play a pivotal role in skin homeostasis and disease. Although the use of biopsies to sample these cytokines from human skin is widely employed in dermatological practice, knowledge about less invasive, in vivo sampling methods is scarce. The aim of this study was to provide an overview of such methods by systematically reviewing studies in Medline, EMBASE, Web of Science and Cochrane Library using combinations of the terms "IL-1α", IL-1RA", "skin", "human", including all possible synonyms. Quality was assessed using the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) checklist. The search, performed on 14 October 2016, revealed 10 different sampling methods, with varying degrees of invasiveness and wide application spectrum, including assessment of both normal and diseased skin, from several body sites. The possibility to sample quantifiable amounts of cytokines from human skin with no or minimal discomfort holds promise for linking clinical outcomes to molecular profiles of skin inflammation.

Evaluating the autoinduction expression system and one-step purification for high-level expression and purification of gallbladder-derived rhIL-1Ra.

Recent advancement in fermentation technologies resulted in the increased yields of recombinant proteins of biopharmaceutical and medicinal importance. Consequently, there is an important task to develop simple and easily scalable methods that can facilitate the production of high-quality recombinant protein. Most of the recent reports described the expression of recombinant human IL-1 receptor antagonist (rhIL-1Ra) in Escherichia coli using isopropyl-ß-d-thiogalacto pyranoside (IPTG), a nonmetabolizable and expensive compound, as an expression inducer. In this study, we describe the expression and one-step purification of gallbladder-derived rhIL-1Ra by autoinduction in E. coli. This method includes special media that automatically induce the target protein expression from T7 promoter and allow the production of the target protein in high yield than the conventional IPTG induction method. In addition to fermentation process improvements, one-step purification strategy is essential to make the process economical. We developed a single-step cation exchange chromatography and obtained 300 mg/L of rhIL-1Ra with 98% purity. Purified protein was characterized by SDS-PAGE and Ion exchange HPLC (IEX-HPLC). The described method can be used to scale up the production of rhIL-1Ra and other recombinant proteins.

Expression and characterization of human glycosylated interleukin-1 receptor antagonist in Pichia pastoris.

Interleukin-1 receptor antagonist is an inhibitor of the pro-inflammatory action of interleukin-1. The gene encoding for interleukin-1 receptor antagonist (IL-1ra) was cloned into a Pichia pastoris expression vector pPICzalphaA (Invitrogen, USA) and transformed into P. pastoris strain SMD1168H. Multi-copy selection of the gene produced a high expressing strain of IL-1ra that produced 17mg/L of total secreted purified protein. The IL-1ra produced in P. pastoris was a mixture of glycosylated and non-glycosylated IL-1ra where 70% of the total protein was glycosylated. SP-Sepharose purification allowed for separation of the two expressed forms of IL-1ra, which permits biochemical investigation of glycosylated and non-glycosylated IL-1ra using one expression system. Mass spectrometric analysis revealed the expression of the full-length protein and that the glycosylated IL-1ra contained high mannose glycoforms that ranged from Man(9)GlcNAc(2) to Man(14)GlcNAc(2).

Specific volume and adiabatic compressibility measurements of native and aggregated recombinant human interleukin-1 receptor antagonist: density differences enable pressure-modulated refolding.

High hydrostatic pressures have been used to dissociate non-native protein aggregates and foster refolding to the native conformation. In this study, partial specific volume and adiabatic compressibility measurements were used to examine the volumetric contributions to pressure-modulated refolding. The thermodynamics of pressure-modulated refolding from non-native aggregates of recombinant human interleukin-1 receptor antagonist (IL-1ra) were determined by partial specific volume and adiabatic compressibility measurements. Aggregates of IL-1ra formed at elevated temperatures (55 degrees C) were found to be less dense than native IL-1ra and refolded at 31 degrees C under 1,500 bar pressure with a yield of 57%. Partial specific adiabatic compressibility measurements suggest that the formation of solvent-free cavities within the interior of IL-1ra aggregates cause the apparent increase in specific volume. Dense, pressure-stable aggregates could be formed at 2,000 bar which could not be refolded with additional high pressure treatment, demonstrating that aggregate formation conditions and structure dictate pressure-modulated refolding yields.