Expression of recombinant human coagulation factor VII by the Lizard Leishmania expression system

Heterologous Expression of Human IFNγ and Anti-IL17 Antibody in Leishmania tarentolae Promastigote

BACKGROUND

Leishmania is an intracellular flagellate protozoan parasite that causes a wide range of clinical diseases in humans. The basis of immunological resistance against leishmaniasis depends on Thl reactions and is within the time period of cytokine function.

METHODS

In this study, human anti-IL17 antibody and IFNγ-producing promastigote were produced to be used in leishmanization. A sequence of light and heavy chains' gene of anti-IL17 antibody and human IFNγ (hIFNγ) was obtained from the NCBI database and synthesized in the ECORV reaction site in the plasmid pGH, which it's called pGH-hIFNγ-antiIL17. The synthesized part using the restriction enzyme ECORV was extracted from the plasmid and after purification by electroporation was transferred to Iranian lizard Leishmania (I.L.L). Evaluation of structural presence in the I.L.L genome at the level of DNA and mRNA was assessed. The expressions of hIFNγ and anti-IL17 were evaluated and confirmed using ELISA and western blot analysis. The hIFNγ secreted from the culture medium was collected at high concentrations of 124.36 ± 6.47 pg/mL.

RESULTS

Targeted gene replacement into the I.L.L genome was successfully performed for the first time using the pGH-hIFNγ-antiIL17 plasmid in an identical replacement process. Stabilized recombinant DNA contains a target gene that has no toxicity to the parasite.

CONCLUSIONS

The effective achievement of producing a recombinant gene was done for the first time by replacing the I.L.L-CPC gene with plasmid pGH-hIFNγ-antiIL17 by targeted gene replacement. This cab can regulate the production of hIFNγ and anti-IL17. This makes it a viable choice for eliminating leishmania.

Comparing the Yield of Recombinant Human Factor VII Protein Expressed by the rDNA-Promoter with the CMV-Promoter in Iranian Lizard Leishmania

Background

Iranian Lizard Leishmania (I.L.L) is a nonpathogenic Leishmania strain. Due to its advantages, several recombinant proteins have been produced in this host. However, I.L.L shows a lower yield of recombinant protein expression compared to other commercial hosts. Considering the role of protease enzymes in protein digestion, we selected cysteine protease B (CPB) to investigate its impact on recombinant protein yield in I.L.L.

Methods

we generated gene knockouts by utilizing homologous recombination (HR) and CRISPR methods. To assess the efficacy of the designed construct, we compared the yield of recombinant human factor VII (rhFVII) production between cells transfected with the pLEXSY-hyg2-FVII vector and the CMV-promoter-based construct (pF7cmvneo).

Results

The knockout of a single CPB gene allele through the HR method or the complete knockout of all alleles through the CRISPR method led to cell death. This outcome suggests that even the deletion of a single CPB gene allele diminishes the protein to a level insufficient for the survival of I.L.L, indicating a critical dependency on the presence of this protein for the organism's viability. rhFVII exhibited a greater expression yield with the pLEXSY construct compared to the pF7cmvneo construct in I.L.L. The lower expression rate of pF7cmvneo may be influenced by epigenetic factors related to the CPC gene or the RNA polymerase used for the expression of that promoter.

Conclusion

Therefore, considering alternative integration targets for CMV-promoter-based constructs and incorporating UTR sequences of I.L.L high-expression proteins in the vector may enhance recombinant protein expression rates.

Detection and quantification of single chain rFVII impurity in final drug products by SE-UPLC and CE-SDS as an alternative to SDS-PAGE

Recombinant factor VII, produced in recombinant BHK cell line, is secreted as a single chain zymogen form (rFVII, non-activated) in cell culture supernatant and subsequently converts to its active form during anion exchange chromatography step in the downstream purification process, with the aid of calcium ion. Single chain rFVII impurity (non-activated form) in final drug products should not exceed more than 3.0 % of total rFVIIa content. Therefore, one of the most essential quality control tests in pharmaceutical companies is to precisely quantify and report this impurity. SDS-PAGE, as a traditional method in quality control laboratories to quantify single chain rFVII, is a laborious, time-consuming, low output, and semi-quantitative method for quantification of non-activated form impurity which utilizes a densitometer to scan the gel and calculate the non-activated form band density. In this work, we developed two novel instrumental-based techniques (SE-UPLC and CE-SDS) with superior precision, accuracy, sensitivity, and efficiency that overcome SDS-PAGE shortcomings. The results of both methods were comparable to SDS-PAGE and showed an even higher correlation with expected values. Finally, we concluded that these two methods could be used as a high throughput routine method in quality control laboratories as an alternative choice to manual SDS-PAGE.

Preliminary Information of Iranian Lizard Leishmania Promastigote Transcriptome Sequencing by Next Generation Sequencing (NGS) Method

Background

A lizard Leishmania has been isolated from a lizard (Agama agilis) in Iran. Its genome sequence has not been determined, so far.

Methods

The study was done at Shahid Beheshti University of Medical Sciences, Tehran, Iran in 2017-2023. Leishmania promastigotes were cultured in RPMI1640 culture medium and collected at logarithmic phase by centrigugation. Parasite RNA was extracted by the Qiagene standard kit and its quantity and quality was determined and sequenced by NGS method with Illumina PE machine at BGI Company (China).

Results

The number of 8316 mRNA, 83 tRNA, 63 rRNA, 83 ncRNA, 5 snRNA, 1039 snoRNA, 36 region, and 3 repeat regions, 8343 CDS, 9597 Exon and 9292 Genes were identified in promastigote of Iranian lizard Leishmania.

Conclusion

Genomic elements of Iranian lizards Leishmania (with unique characteristics) were determined and identified by NGS system.

The Influence of Different Culture Media on the Growth and Recombinant Protein Production of Iranian Lizard Leishmania Promastigote

Background

Leishmania is a eukaryotic protozoan parasite belonging to the Trypanosomatidae family. The Iranian Lizard Leishmania (I.L.L.), which is nonpathogenic to mammals, shows great promise to be used as an expression system for recombinant protein production. Unlike other Leishmania strains, the ideal culture medium for I.L.L. has not been established, although it is commonly cultured in the RPMI1640 medium.

Methods

We investigated the growth rate of the wild and recombinant I.L.L. in BHI, RPMI1640, LB, and M199 media with and without FBS, hemin, or lyophilized rabbit serum. Subsequently, the expression rate of the recombinant protein in these media was compared.

Results

The growth rate of I.L.L. in RPMI1640 medium and LB broth was similar and supplementation with 10% FBS did not affect the growth rate. The amount of protein expression in the LB medium was higher than in the other three media.

Conclusion

The LB broth is an appropriate medium for I.L.L. culture and recombinant protein production.

Purification and Characterization of Recombinant Darbepoetin Alfa from Leishmania tarentolae

Darbepoetin alfa is a biopharmaceutical glycoprotein that stimulates erythropoiesis and is used to treat anemia, which associated with renal failure and cancer chemotherapy. We herein describe the structural characterization of recombinant darbepoetin alfa produced by Leishmania tarentolae T7-TR host. The DNA expression cassette was integrated into the L. tarentolae genome through homologous recombination. Transformed clones were selected by antibiotic resistance, diagnostic PCRs, and protein expression analysis. The structure of recombinant darbepoetin alfa was analyzed by isoelectric focusing, ultraviolet-visible spectrum, and circular dichroism (CD) spectroscopy. Expression analysis showed the presence of a protein band at 40 kDa, and its expression level was 51.2 mg/ml of culture medium. Darbepoetin alfa have 5 isoforms with varying degree of sialylation. The UV absorption and CD spectra were analogous to original drug (Aranesp), which confirmed that the produced protein was darbepoetin alfa. Potency test results revealed that the purified protein was biologically active. In brief, the structural and biological characteristics of expressed darbepoetin alfa were very similar to Aranesp which has been normally expressed in CHO. Our data also suggest that produced protein has potential to be developed for clinical use.

Non-conventional expression systems for the production of vaccine proteins and immunotherapeutic molecules

The increasing demand for recombinant vaccine antigens or immunotherapeutic molecules calls into question the universality of current protein expression systems. Vaccine production can require relatively low amounts of expressed materials, but represents an extremely diverse category consisting of different target antigens with marked structural differences. In contrast, monoclonal antibodies, by definition share key molecular characteristics and require a production system capable of very large outputs, which drives the quest for highly efficient and cost-effective systems. In discussing expression systems, the primary assumption is that a universal production platform for vaccines and immunotherapeutics will unlikely exist. This review provides an overview of the evolution of traditional expression systems, including mammalian cells, yeast and E.coli, but also alternative systems such as other bacteria than E. coli, transgenic animals, insect cells, plants and microalgae, Tetrahymena thermophila, Leishmania tarentolae, filamentous fungi, cell free systems, and the incorporation of non-natural amino acids.

Enhanced recombinant factor VII expression in Chinese hamster ovary cells by optimizing signal peptides and fed-batch medium

Signal peptides play an important role in directing and efficiently transporting secretory proteins to their proper locations in the endoplasmic reticulum of mammalian cells. The aim of this study was to enhance the expression of recombinant coagulation factor VII (rFVII) in CHO cells by optimizing the signal peptides and type of fed-batch culture medium used. Five sub-clones (O2, I3, H3, G2 and M3) with different signal peptide were selected by western blot (WB) analysis and used for suspension culture. We compared rFVII expression levels of 5 sub-clones and found that the highest rFVII expression level was obtained with the IgK signal peptide instead of Ori, the native signal peptide of rFVII. The high protein expression of rFVII with signal peptide IgK was mirrored by a high transcription level during suspension culture. After analyzing culture and feed media, the combination of M4 and F4 media yielded the highest rFVII expression of 20 mg/L during a 10-day suspension culture. After analyzing cell density and cell cycle, CHO cells feeding by F4 had a similar percentage of cells in G0/G1 and a higher cell density compared to F2 and F3. This may be the reason for high rFVII expression in M4+F4. In summary, rFVII expression was successfully enhanced by optimizing the signal peptide and fed-batch medium used in CHO suspension culture. Our data may be used to improve the production of other therapeutic proteins in fed-batch culture.

Expression of Recombinant Human Amelogenin in Iranian Lizard Leishmania and Its Biological Function Assay

BACKGROUND

Amelogenins are the major components of enamel matrix proteins. Enamel matrix derivatives (EMD) can be used in periodontal diseases to regenerate periodontal tissues. The main aim of this study was to evaluate expression of full-length functional recombinant human amelogenin (rhAm) in Iranian lizard Leishmania (I.L.L.) as an alternative eukaryotic expression system.

METHODS

Human cDNA encoding a 175-amino acid amelogenin expression cassette was sub cloned into a pLEXSY vector. The construct was transferred into Leishmania cells by electroporation. The protein production was surveyed in the transcription and the translation levels. The expressed protein was purified and some of its biological properties were investigated in comparison to EMD and negative control.

RESULTS

Expression of rhAm was confirmed by RT-PCR and western blot test in Leishmania cells. Purified rhAm significantly inhibited the formation of tartrate-resistant acid phosphatase positive (TRAP(+)) multinuclear cells in calcitriol stimulated mouse marrow cultures. Moreover, it significantly promoted proliferation and DNA synthesis in L929 mouse fibroblast cells.

CONCLUSION

Functional rhAm was successfully expressed in I.L.L. Easy handling and post translation modification were the main advantages of this expression system. It is suggested to investigate molecular properties of this rhAm in the future.

Cloning and Expression of Leishmania infantum LPG3 Gene by the Lizard Leishmania Expression System

BACKGROUND

Various prokaryotic and eukaryotic expression systems have been developed for the production of recombinant proteins. In the present study, we used a new protein expression system based on the Iranian Lizard Leishmania, a trypanosomatid protozoan as a host, for the expression of LPG3 gene from Leishmania infantum (L.infantum).

METHODS

The LPG3 gene was cloned in the expression cassette for integration into the small subunit of the ribosomal RNA locus of Lizard Leishmania genome by electroporation. Expression of the recombinant LPG3 protein was confirmed by western blotting and immunofluorescence staining.

RESULTS

Western blotting confirmed the expression and production of rLPG3 protein. Immunofluoresence analysis also revealed the staining throughout the cytoplasm of transfected parasites, indicating that the protein has been expressed.

CONCLUSION

These results demonstrate that Leishmania cells can be suggested an expression system for the production of recombinant LPG3 (rLPG3) to further research in vaccine designing against leishmaniasis.

Genomic organization of leishmania species

Leishmania is a protozoan parasite belonging to the family Trypanosomatidae, which is found among 88 different countries. The parasite lives as an amastigote in vertebrate macrophages and as a promastigote in the digestive tract of sand fly. It can be cultured in the laboratory using appropriate culture media. Although the sexual cycle of Leishmania has not been observed during the promastigote and amastigote stages, it has been reported by some researchers. Leishmania has eukaryotic cell organization. Cell culture is convenient and cost effective, and because posttranslational modifications are common processes in the cultured cells, the cells are used as hosts for preparing eukaryotic recombinant proteins for research. Several transcripts of rDNA in the Leishmania genome are suitable regions for conducting gene transfer. Old World Leishmania spp. has 36 chromosomes, while New World Leishmania spp. has 34 or 35 chromosomes. The genomic organization and parasitic characteristics have been investigated. Leishmania spp. has a unique genomic organization among eukaryotes; the genes do not have introns, and the chromosomes are smaller with larger numbers of genes confined to a smaller space within the nucleus. Leishmania spp. genes are organized on one or both DNA strands and are transcribed as polycistronic (prokaryotic-like) transcripts from undefined promoters. Regulation of gene expression in the members of Trypanosomatidae differs from that in other eukaryotes. The trans-splicing phenomenon is a necessary step for mRNA processing in lower eukaryotes and is observed in Leishmania spp. Another particular feature of RNA editing in Leishmania spp. is that mitochondrial genes encoding respiratory enzymes are edited and transcribed. This review will discuss the chromosomal and mitochondrial (kinetoplast) genomes of Leishmania spp. as well as the phenomenon of RNA editing in the kinetoplast genome.