Expression and one step intein-mediated purification of biologically active human G-CSF in Escherichia coli.

Recombinant form of granulocyte colony stimulating factor (G-CSF) was first approved by FDA in 1998 for chemotherapy induced neutropenia. However, despite production of its biosimilars, less expensive production of G-CSF could reduce the overall therapeutic cost. The aim of this study was to evaluate the possibility of producing biologically active recombinant G-CSF via a single step purification procedure mediated by a self-cleavable intein. G-CSF was expressed by E. coli BL21 (DE3) through IPTG induction, followed by its purification using pH optimization on a chitin column. Western blotting, ELISA, size exclusion chromatography, circular diachorism, peptide mapping, and in vitro assays were performed to compare the structural similarity and biological activity of the purified G-CSF with Neupogen™. Protein purification was confirmed by revealing a band of approximately 18.8 kDa on SDS-PAGE. Bioactivity and physicochemical assays based on the US pharmacopeia showed almost identical or acceptable ranges of similarities between recombinant G-CSF and Neopogen™. this study, biologically active soluble recombinant G-CSF was successfully produced with high purity without using chaotropic solvents through a one-step procedure. This shorter and more efficient purification procedure can reduce the cost and time of G-CSF production which makes its industrial production more cost-effective and might be also applicable for production of other biopharmaceuticals.

Improvement of soluble expression of GM-CSF in the cytoplasm of Escherichia coli using chemical and molecular chaperones.

The most common approaches to improve soluble expression of heterologous proteins are applications of molecular chaperones such as DnaK, DnaJ, GrpE, GroEL and GroES. The aim of present study was to enhance soluble expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) in Escherichia coli by different approaches including modification of cultivation and induction conditions, and thermally, genetically and chemically enhancement of expression of cellular chaperones. To genetically enhance amount of molecular chaperones, co-expression of pET28-GM-CSF and pKJE7 plasmids was performed. The soluble expressed protein was affinity purified and subjected to endotoxin removal. Co-expression with molecular chaperones significantly increased soluble expression of GM-CSF. Addition of chemical chaperones and osmolytes like NaCl (0.5 M), sucrose (0.5 M), sorbitol (0.5 M) and MgCl2 (1 mM) to growing media could improve solubility of GM-CSF. Biological activity of purified GM-CSF was confirmed based on its proliferative effect on HL-60 cell lines. The approach developed in the present study can be applied to improve soluble expression of other recombinant protein proteins.

Effect of Tamarindus indica L. fruit pulp and seed extracts on experimental ulcerative colitis in rats.

Background and purpose: Tamarindus indica L. which has anti-inflammatory, radical scavenging, and ulcer healing effects can be useful for the alleviation of inflammatory bowel disease (IBD). Therefore, the effects of T. indica fruit pulp (TIPE) and seed extracts (TISE) were investigated on experimental colitis. Experimental approach: TIPE and TISE (125, 250, and 500 mg/kg) were made by maceration (ethanol/water: 80/30) and administered to male Wistar rats with acetic acid-induced colitis. Prednisolone (4 mg/kg) and mesalazine (100 mg/kg) were used as reference drugs. The colon tissues were examined for macroscopic and pathologic parameters and myeloperoxidase (MPO) and malondialdehyde (MDA) values. Findings/Results: The total phenols were 45.7 ± 1.1 and 453.0 ± 3.3 mg/g in terms of gallic acid for TIPE and TISE, respectively. Both of the extracts significantly improved most of the investigated parameters including body weight loss, the weight of colons, indices of ulcers, and total colitis. MPO activity and MDA in the treatment groups (except for TIPE at 125 mg/Kg) significantly decreased compared to the control. Conclusion and implications: Both TIPE and TISE were effective in the treatment of colitis however it seems that the effective ingredients were more concentrated in seeds rather than pulp extract so the highest dose of seed extract had a competitive effect with reference drugs. More studies are needed to introduce T. indica as a suitable complementary medicine or food for patients with IBD.