Recombinant expression and purification of functional vascular endothelial growth factor-121 in the baculovirus expression system

Bi-functional KIT-PR1P peptides combine with VEGF to protect ischemic kidney in rats by targeting to Kim-1

Introduction

Acute kidney injury (AKI) was a disease with a high mortality mainly caused by renal ischemia/reperfusion injury (I/R). Although the current non-targeted administration of vascular endothelial growth factor (VEGF) for AKI had been revealed to facilitate the recovery of renal I/R, how to targeted deliver VEGF and to retain it efficiently in the ischemic kidney was critical for its clinical application.

Methods

In present study, bi-functional KIT-PR1P peptides were constructed which bond VEGF through PR1P domain, and targeted ischemic kidney through KIT domain to interact with biomarker of AKI-kidney injury molecule-1 (Kim-1). Then the targeted and therapeutic effects of KIT-PR1P/VEGF in AKI was explored in vitro and in vivo.

Results

The results showed KIT-PR1P exhibited better angiogenic capacity and targeting ability to hypoxia HK-2 cells with up-regulated Kim-1 in vitro. When KIT-PR1P/VEGF was used for the treatment of renal I/R through intravenous administration in vivo, KIT-PR1P could guide VEGF and retain its effective concentration in ischemic kidney. In addition, KIT-PR1P/VEGF promoted angiogenesis, alleviated renal tubular injury and fibrosis, and finally promoted functional recovery of renal I/R.

Conclusion

These results indicated that the bi-functional KIT-PR1P peptides combined with VEGF would be a promising strategy for the treatment of AKI by targeting to Kim-1.

In vivo solid tumor targeting with recombinant VEGF-diphtheria immunotoxin

Objectives

A variety of signaling molecules have been identified that play a role in angiogenesis, of prime importance, vascular endothelial growth factor (VEGF) and its resceptor (VEGFR), which is highly expressed in most human solid tumors. Targeting VEGF or/and VEGFR with immunotoxin may be a promising approach to directly affect cancer cells. Immunotoxins are for targeted treatment comprising two functional moieties, an antibody that binds to target cells along with toxin that kills molecules.

Materials and Methods

In this study, an immunotoxin comprising domain of diphtheria toxin subunit A (DT386) genetically fused to mouse VEGF (mVEGF-DT) was developed. The second construct, which contains the DT386 domain, was made to investigate the action of the DT386 domain on tumor cells. Both gene constructs were cloned, expressed, and were further purified. The biological activity of mVEGF-DT and DT386 proteins was assessed on the TC1 cell line bearing mouse model. Proteins were injected intra-tumoral in mice, in separate groups.

Results

Tumors in the mVEGF-DT group started to dwindle after six injections, but tumor size in both control groups (DT386 and PBS), continued to grow.

Conclusion

Successful targeting of solid tumor cells by mVEGF-DT immunotoxin demonstrates the therapeutic potential utility of these conjugates for tumor targeting.

Molecular mechanism responsible for the hyperexpression of baculovirus polyhedrin

One of the amazing phenomena in the baculovirus life cycle is the hyperexpression of the very late gene, polyhedrin (polh), causing the production of the occlusion bodies where progeny virions are embedded. However, to date, the molecular mechanism underlying its hyperexpression is not completely elucidated. Considering that, in this review, the mechanism responsible for its hyperexpression from the previous studies up to now was comprehensively summarized from three aspects, namely, the structure characteristics of the polh promoter and transcription regulation, the structure and translation regulation of the polh mRNA, and especially the regulators that influence the expression of polh gene. Moreover, this review will help us obtain a better understanding about the hyperexpression of polh, and also provide guidance for improving the expression efficiency of the foreign proteins by adopting the baculovirus expression vector system.

Effective production of human growth factors in Escherichia coli by fusing with small protein 6HFh8

Background

Growth factors (GFs) are signaling proteins that affect cellular processes such as growth, proliferation, and differentiation. GFs are used as cosmeceuticals, exerting anti-wrinkle, anti-aging, and whitening effects, and also as pharmaceuticals to treat wounds, growth failure, and oral mucositis. However, in mammalian and bacterial cells, low productivity and expression in inclusion bodies, respectively, of GFs does not satisfy the consumer demand. Here, we aimed to develop a bacterial expression system that produces high yields of soluble GFs that can be purified in their native forms.

Results

We present Fh8, an 8-kDa peptide from Fasciola hepatica with an N-terminal hexa-histidine (6HFh8), as a fusion partner for enhanced human GF production in recombinant Escherichia coli. The fusion partner harboring a tobacco etch virus (TEV) protease cleavage site was fused to the N-terminus of 10 human GFs: acidic and basic fibroblast growth factors (aFGF and bFGF, respectively), epidermal growth factor (EGF), human growth hormone (hGH), insulin-like growth factor 1 (IGF-1), vascular endothelial growth factor 165 (VEGF165), keratinocyte growth factor 1 (KGF-1), placental growth factor (PGF), stem cell factor (SCF), and tissue inhibitor of metalloproteinase 1 (TIMP-1). The fusion proteins were expressed in E. coli under the control of T7 promoter at three temperatures (25 °C, 30 °C, and 37 °C). All individual fusion proteins, except for SCF and TIMP-1, were successfully overexpressed in cytoplasmic soluble form at more than one temperature. Further, the original aFGF, IGF-1, EGF, and VEGF165 proteins were cleaved from the fusion partner by TEV protease. Five-liter fed-batch fermentation approaches for the 6HFh8-aFGF (lacking disulfide bonds) and 6HFh8-VEGF165 (a cysteine-rich protein) were devised to obtain the target protein at concentrations of 9.7 g/l and 3.4 g/l, respectively. The two GFs were successfully highly purified (> 99% purity). Furthermore, they exerted similar cell proliferative effects as those of their commercial equivalents.

Conclusions

We demonstrated that 6HFh8-GF fusion proteins could be overexpressed on a g/l scale in the cytoplasm of E. coli, with the GFs subsequently highly purified and maintaining their biological activity. Hence, the small protein 6HFh8 can be used for efficient mass-production of various GFs.

Expressing of Recombinant VEGFR2-specific Nanobody in Baculovirus Expression System

Background

Baculovirus expression system, introduced more than 20 years ago, is considered as a useful tool for large and complex eukaryotic recombinant protein production. A baculovirus expression vector is a recombinant virus which desired foreign protein coding sequences is under control of the virus gene promoter. Baculovirus only infects insect cells and do not normally infect vertebrates therefore, they possess no risk of biological risks for human.

Objectives

The aim of this study was to recombinant expression of vascular endothelial growth factor (VEGF) reseptor-2 specific Nanobody in the baculovirus expression system.

Materials and Methods

Gene of specific Nanobody against the VEGF reseptor-2 that called 3VGR19 was cloned and expressed in baculovirus system.

Results

3VGR19 Nanobody gene was amplified by Polymerase Chain Reaction (PCR) using the specific primers, and was cloned in pFastBac HTA plasmid. DH10Bac bacteria was transformed with resulted donor plasmid. The cultured Sf9 insect cell line was transfected with recombinant bacmid, and finally, the expression and purification of 3VGR19 was confirmed in insect cells.

Conclusions

In conclusion, Transient infection of insect cells with baculovirus can be a promising technology for expression of antibody fragments.

Expression of a New Recombinant Collagenase Protein of Lucilia Sericata in SF9 Insect Cell as a Potential Method for Wound Healing

BACKGROUND

Today, the use of maggot therapy has become widespread due to the increase in chronic ulcers in the world. The recombinant production of secreted enzymes from these larvae is a novel non-invasive method for the treatment of chronic ulcers. Lucilia Sericata (L. sericata) collagenase (MMP-1) has been expressed in insect cells. Collagenase is an enzyme that is widely used in clinical therapy and industry. It has been indicated that collagenase is expressed and secreted in salivary glands of L. sericata while using for maggot debridement therapy.

OBJECTIVES

In the present study we decided to produce the recombinant form of collagenase enzyme in Spodoptera frugiperda (SF9) insect cells using the baculovirus expression system (Bac-to-Bac).

MATERIALS AND METHODS

cloned the coding sequences (residues 494-1705) of L. sericata collagenase into the pFastBacHTA as donor plasmid. After transposition in the bacmid of DH10Bac host, the bacmid was transfected into the Sf9 cell line, then the expressed recombinant collagenase (MMP-1) was purified using the Ni-NTA agarose.

RESULTS

The recombinant protein was verified by Western blotting. Furthermore, the biological activity of purified protein was measured in the presence of its specific substrate and its inhibitor, which was 67 IU.mL-1 based on our results, it was revealed that the characterized gene in our previous study codes L. sericata collagenesa enzyme.

CONCLUSION

Considering to the broad applications of collagenase in medical sciences, for the first time, we cloned the L. sericata collagenase (MMP-1) gene into the insect cell line to establish a method for the expression and purification of L. sericata collagenase (MMP-1). The result help for preparing and designing a safe and versatile recombinant drug in future.