Optimization of conditions for high-level expression and purification of human recombinant consensus interferon (rh-cIFN) and its characterization

Evaluation of exosomes encapsulated recombinant Interleukin-29 for its in vitro anticancer studies

Exosomes have recently been considered ideal biotherapeutic nanocarriers that broaden the frontiers of current drug delivery systems to overcome the shortcomings associated with cytokine-based immunotherapy. Using this approach, the current study aimed to assess anti-proliferative activity of purified IL-29 and exosomes encapsulated IL-29. The IL-29+pET-28a construct was transformed into Rosetta 2(DE3) cells which was used for the large-scale production of IL-29. Exosomes isolated from H1HeLa, and SF-767 cells using Total Exosome Isolation reagent were loaded with IL-29 via sonication. Isolation of exosomes was validated using their core protein signature by western blotting and specific miRNA profiles by RT-PCR. The drug loading efficiency of exosomes derived from H1HeLa cells was higher than that of SF-767-derived exosomes. The drug release kinetics of IL-29 encapsulated exosomes exhibited stable release of the recombinant drug. Around 50% of all cancer cell lines survived when IL-29 was administered at a concentration of 20 µg/mL. A survival rate of less than 10% was observed when cells were treated with 20 µg/mL IL-29 loaded exosomes. It was concluded that IL-29 loaded exosomes had a more significant cytotoxic effect against cancer cells, which might be attributed to sustained drug release, improved half-life, superior targeting efficacy, capacity to harness endogenous intracellular trafficking pathways, and heightened biocompatibility of exosomes.

Types of Interferons and Their Expression in Plant Systems

Interferons (IFNs) are divided into 3 types (type I, type II, and type III) on the basis of sequence homology and functional properties. Recombinant IFNs have been approved by regulatory agencies in many countries for clinical treatment of hepatitis B, hepatitis C, and other diseases; these IFNs are mainly produced in microorganisms and mammalian cell systems. However, there are serious obstacles to the production of recombinant IFNs in microorganism systems; for example, the recombinant IFN may have different glycosylation patterns from the native protein, be present in insoluble inclusion bodies, be contaminated with impurities such as endotoxins and nucleic acids, have a short half-life in human blood, and incur high production costs. Some medicinal proteins have been successfully expressed in plants and used in clinical applications, suggesting that plants may also be a good system for IFN expression. However, there are still many technical problems that need to be addressed before the clinical application of plant-expressed IFNs, such as increasing the amount of recombinant protein expression and ensuring that the IFN is modified with the correct type of glycosylation. In this article, we review the classification of IFNs, their roles in antiviral signal transduction pathways, their clinical applications, and their expression in plant systems.

Strategies for the Production of Soluble Interferon-Alpha Consensus and Potential Application in Arboviruses and SARS-CoV-2

Biopharmaceutical production is currently a multibillion-dollar industry with high growth perspectives. The research and development of biologically sourced pharmaceuticals are extremely important and a reality in our current healthcare system. Interferon alpha consensus (cIFN) is a non-natural synthetic antiviral molecule that comprises all the most prevalent amino acids of IFN-α into one consensus protein sequence. For clinical use, cIFN is produced in E. coli in the form of inclusion bodies. Here, we describe the use of two solubility tags (Fh8 and DsbC) to improve soluble cIFN production. Furthermore, we analyzed cIFN production in different culture media and temperatures in order to improve biopharmaceutical production. Our results demonstrate that Fh8-cIFN yield was improved when bacteria were cultivated in autoinduction culture medium at 30 °C. After hydrolysis, the recovery of soluble untagged cIFN was 58% from purified Fh8-cIFN molecule, fourfold higher when compared to cIFN recovered from the DsbC-cIFN, which achieved 14% recovery. The biological activity of cIFN was tested on in vitro model of antiviral effect against Zika, Mayaro, Chikungunya and SARS-CoV-2 virus infection in susceptible VERO cells. We show, for the first time, that cIFN has a potent activity against these viruses, being very low amounts of the molecule sufficient to inhibit virus multiplication. Thus, this molecule could be used in a clinical approach to treat Arboviruses and SARS-CoV-2.

Exploring a combined Escherichia coli-based glycosylation and in vitro transglycosylation approach for expression of glycosylated interferon alpha

The conventional use of E. coli system for protein expression is limited to non-glycosylated proteins. While yeast, insect and mammalian systems are available to produce heterologous glycoproteins, developing an engineered E. coli-based glycosylation platform will provide a faster, more economical, and more convenient alternative. In this work, we present a two-step approach for production of a homogeneously glycosylated eukaryotic protein using the E. coli expression system. Human interferon α-2b (IFNα) is used as a model protein to illustrate this glycosylation scheme. In the first step, the N-glycosyltransferase from Actinobacillus pleuropneumoniae (ApNGT) is co-expressed for in vivo transfer of a glucose residue to IFNα at an NX(S/T) N-glycosylation sequon. Several E. coli systems were examined to evaluate the efficiency of IFNα N-glucosylation. In the second step, the N-glucosylated protein is efficiently elaborated with biantennary sialylated complex-type N-glycan using an in vitro chemoenzymatic method. The N-glycosylated IFNα product was found to be biologically active and displayed significantly improved proteolytic stability. This work presents a feasible E. coli-based glycosylation machinery for producing therapeutic eukaryotic glycoproteins.

Production of potent long-lasting consensus interferon using albumin fusion technology in Pichia pastoris expression system

Consensus interferon (cIFN) is a wholly synthetic therapeutic protein which is used to treat hepatitis C/B and certain types of malignancies. It has short serum half-life, therefore, to maintain its therapeutic level in the human body it requires thrice-weekly administration. Various strategies like PEGylation and micro-encapsulation have been developed during the last few years to enhance the pharmacokinetics of small therapeutic peptides. This study executed the human albumin-fusion technology, a simple and flexible approach to extend the serum circulating half-life of cIFN, because human serum albumin (HSA) has long circulating half-life (19 days) and very minute immunological activities. We integrated the codon-optimized HSA-cIFN fusion gene into Pichia pastoris genome by homologous recombination. The selection of hyper-resistant P. pastoris clone against Zeocin™ achieved a high-level secretory expression (250 mg/L) of fusion protein. HSA-cIFN fusion protein was purified using one-step purification by affinity chromatography with 34% recovery. The SDS-PAGE and SEC-HPLC analysis confirmed the final purified product has molecular weight of 87 kDa with 98% purity. Western blot analysis using anti-IFN antibodies further verified the purified HSA-cIFN fusion protein. The specific biological activity was 2.1 × 10⁶ IU/mg as assessed by cytopathic inhibition assay, and half-life of fusion protein was estimated by in vitro thermal and proteolytic stability studies. This work concludes that by using albumin fusion technology, codon optimization and one-step purification a high yield of 86 mg/L of biologically active protein with improved serum half-life was obtained.

Evaluating the ion exchange chromatography for matrix-assisted PEGylation and purification of consensus interferon

Scientists have implemented protein-PEGylation technology for boosting-up the pharmacokinetics and stability of recombinant therapeutic proteins. In the present study, (a) matrix-assisted PEGylation was compared with solution-phase PEGylation and (b) matrix-assisted PEGylation was performed with different ion exchange resins for impact of chromatography medium on yield and purity of PEGylated product. DEAE Sepharose CL 6B, DEAE Fracto gel, and Macro cap Q ion exchange chromatography medium were compared for on column PEGylation and purification of cIFN. A MSC-PEG of 12.0 KDa was selected. cIFN was bound to ion exchange medium, and PEG solution was passed through resin for 180 Min, and protein was eluted by sodium chloride linear gradient. Yield and purity for mono-PEGylated cIFN with Macro cap Q matrix was 75% and 99%, respectively, whereas for DEAE Sepharose was 45% and 60%. DEAE Fracto gel^TM purity was 85% with 50% yield of mono-PEGylated cIFN. Further investigation of in vitro biological activities demonstrated that about 30% antiviral activity was reduced as compared to unmodified cIFN. However, thermal stability was significantly improved. The present study proved that matrix-assisted PEGylation can improve the yield and purity of mono-PEGylated product, and Macro Cap resin provided the highest yield of a homogeneous product. In present study, (a) matrix-assisted PEGylation was compared with solution-phase PEGylation and (b) matrix-assisted PEGylation was performed with different ion exchange resins for impact of chromatography medium on yield and purity of PEGylated product. Matrix-assisted PEGylation increases the yield of mono-PEGylated product and further Macro Cap^TM produced highest yield and purity of PEGylated cIFN.

A camelid nanobody against EGFR was easily obtained through refolding of inclusion body expressed in Escherichia coli

Using anti-EGFR (epidermal growth factor receptor) nanobody is a good choice for diagnoses and therapeutics for high EGFR expression diseases. In the present study, the percentage composition of anti-EGFR nanobody attained 25% of the total cell protein expressed in Escherichia coli BL21 (DE3). However, almost all nanobodies were expressed as inclusion bodies. To acquire active nanobodies, a series of dilution refolding procedures were optimized after inclusion bodies were dissolved into 6 M urea and purified with immobilized metal affinity chromatography. The results showed the refolding rate of the anti-EGFR nanobodies attained to 73%, and about 100 mg nanobodies were refolded from 1 L cells under the conditions that the initial nanobody concentration was 0.3 mg/mL, the dilution speed was 2.5 mL/Min, the dilution buffer was Tris-HCl at pH 8.0, the additives were 0.2 M Arg, 5 mM reduced glutathione (GSH), and 1 mM oxidized glutathione (GSSG). Then the activity of the refolded nanobodies was confirmed. The results showed that the refolded anti-EGFR nanobodies, in a dose-dependent manner, bounded to the tumor cell surface of A431 and MCF-7 and significantly inhibited the proliferation of A431 caused by the epidermal growth factor. Our study provides a facile method to rapidly, efficiently, and massively prepare anti-EGFR antibodies and promotes anti-EGFR-based recognition in cancer diagnoses and therapeutics.

Enhancing recombinant interleukin-6 production yield by fermentation optimization, two-step denaturing, and one-step purification

Interleukin-6 a pleiotropic cytokine involved in a wide range of biological activities. So the large-scale production of biologically active recombinant human interleukin-6 is important for its structural and functional studies. Here, we report an optimized method for shake flask fermentation and a simplified high-yield purification procedure for the recombinant interleukin-6. This high-yield expression method not only involves the optimization of the fermentation condition but also the single step purification method as well as a two-step denaturing and one-step refolding process. This approach replaces the more conventional procedure of protein solubilization and refolding. Through applying these strategies, the final cell density and overall product yield of the recombinant human interleukin-6 were obtained as 20.4 g as cell biomass and 150 mg as purified active protein from the I-L of the culture. The purified protein was characterized by HPLC and SDS-PAGE. The results of the current work demonstrate that the described method may be used to develop the process for industrial-scale production of the biologically active recombinant interleukin-6 protein.

Production of a bioactive recombinant chicken matrix metalloproteinase-11 peptide in Escherichia coli

Matrix metalloproteinase-11 (MMP-11) is known to be highly expressed in metastatic and most invasive forms of tumors. Being selectively expressed in tumor tissues, MMP-11 is a promising target for immunotherapy against tumors. Here, we report the production of a thioredoxin-tagged bioactive recombinant chicken MMP-11 (cMMP-11) peptide excluding the secretory signal and propeptide in Escherichia coli T7 Express lysY using pET32b(+) vector. High-level expression and purification of the bioactive peptide were achieved by induction with 1.0 mM isopropyl-β-d-thiogalactopyranoside for 4 H at 37 °C followed by affinity chromatography under denaturing condition and slow dialysis. The recombinant peptide exhibited both caseinolytic and gelatinase activities without requiring activation by 4-aminophenylmercuric acetate. The antisera raised against the peptide in rabbits showed a strong reaction with the whole recombinant peptide as well as 37 kDa cMMP-11 mature peptide and cross-reactivity with a 43 kDa protein in murine breast tumor of 4T1 origin in Western blot analysis. The 43 kDa protein in the tumor homogenate showed immunoreactivity with a monoclonal antibody against human MMP-11, suggesting it to be murine MMP-11 having cross-reactivity with the antisera raised against cMMP-11 peptide. Altogether, the study characterized the production of a bioactive and immunogenic recombinant cMMP-11 peptide in E. coli.

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-β-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.

Simple procedure applying lactose induction and one-step purification for high-yield production of rhCIFN

Recombinant consensus interferon (CIFN) is a therapeutic protein with molecular weight of 19.5 kDa having broad spectrum antiviral activity. Recombinant human CIFN (rhCIFN) has previously been expressed in Escherichia coli using isopropyl-β-d-thiogalactopyranoside (IPTG), a non-metabolizable and expensive compound, as inducer. For economical and commercial-scale recombinant protein production, it is greatly needed to increase the product yield in a limited time frame to reduce the processing cost. To reduce the cost of production of rhCIFN in E. coli, induction was accomplished by using lactose instead of IPTG. Lactose induction (14 g/L) in shake flask experiment resulted in higher yield as compared with 1 mM IPTG. Finally, with single-step purification on DEAE sepharose, 150 mg/L of >98% pure rhCIFN was achieved. In the present study, an attempt was made to develop a low cost process for producing quality product with high purity. Methods devised may be helpful for pilot-scale production of recombinant proteins at low cost.