•We found a new way to do expression and purification of rat sRAGE protein in Pichia pastoris.•The sRAGE protein could bind the ligand of RAGE, S100A6, in vitro.•The sRAGE protein could prevent rats from liver injury and liver fibrosis in vivo.Soluble receptor for advanced glycation end products (sRAGE), a natural inhibitor of RAGE, is considered to be a putative therapeutic molecule for a variety of diseases and a biomarker for certain conditions. To further study the function of sRAGE, recombinant rat sRAGE (rrsRAGE) was expressed and produced in a eukaryotic system. The open reading frame of rat sRAGE was cloned downstream of the methanol-inducible alcohol oxidase promoter of pPICZαA vector, and Pichia pastoris strain X-33 was used as the host strain. The expression of rrsRAGE was achieved by fermentation in a 15-L bioreactor and the resulting fermentation broth was subjected to purification on a cation exchange chromatography column. The purification of rrsRAGE reached 95% after size exclusion chromatography(SEC). The bioactivity of the purified protein was confirmed in a SH-SY5Y cell proliferation assay. The biological function of the purified rrsRAGE protein rat CCl4-induced model was then examined. Treatment with rrsRAGE resulted in significantly lower liver fibrosis and lower serum level of ALT, suggesting that sRAGE prevent liver from injury and fibrosis. In conclusion, we achieved high-efficiency production of bioactive rrsRAGE in P. pastoris.

Acute intestinal damage induced by chemotherapeutic agent is often a dose-limiting factor in clinical cancer therapy. The aim of this study was to investigate the effect of chemokine CXCL9 on the intestinal damage after chemotherapy and explore the therapeutic potential of anti-CXCL9 agents.In vitro cell proliferation assay was performed with a non-tumorigenic human epithelial cell line MCF10A. Multiple pathway analysis was carried out to explore the pathway that mediated the effect of CXCL9, and the corresponding downstream effector was identified with enzyme-linked immunosorbent assays. Chemotherapy-induced mouse model of intestinal mucositis was prepared by a single injection of the chemotherapeutic agent 5-fluorouracil (5-FU). In vivo expression of cxcl9 and its receptor cxcr3 in intestinal mucosa after chemotherapy was determined by quantitative real-time PCR. Therapeutic treatment with anti-CXCL9 antibodies was investigated to confirm the hypothesis that CXCL9 can contribute to the intestinal epithelium damage induced by chemotherapy.CXCL9 inhibited the proliferation of MCF10A cells by activating phosphorylation of p70 ribosomal S6 kinase (p70S6K), which further promotes the secretion of transforming growth factor beta (TGF-β) as the downstream effector. A blockade of phospho-p70S6K with inhibitor abolished the effect of CXCL9 on MCF10A cells and reduced the secretion of TGF-β. The expression levels of cxcl9 and cxcr3 were significantly up-regulated in intestinal mucosa after 5-FU injection. Neutralizing elevated CXCL9 with anti-CXCR9 antibodies successfully enhanced reconstitution of intestinal mucosa and improved the survival rate of mice that received high-dose chemotherapy.CXCL9 inhibits the proliferation of epithelial cells via phosphorylation of p70S6K, resulting in the excretion of TGF-β as downstream mediator. CXCL9/CXCR3 interaction can exacerbate chemotherapeutic agent-induced intestinal damage, and anti-CXCL9 agents are potential novel therapeutic candidates for promoting mucosal restitution.

Mouse CXCL14/BRAK is a monocyte-selective chemokine which is expressed in almost all normal tissues. A flood of reports on its new functions of tumor suppression and fat metabolism modulation has left CXCL14 a potential therapeutic candidate for these diseases. Therefore, a simple accessible method is on demand for large-scale production of recombinant mouse CXCL14 protein for in vivo animal studies. Here, we introduce an efficient method for large-scale production of recombinant mouse CXCL14, by which an 18-mg protein is produced from 2-L Escherichia coli culture with good bioactivity and low level of endotoxin.

The notch signaling pathway plays an important role in inhibiting cell differentiation and enhancing the repopulation capability of hematopoietic stem/progenitor cells. In this study, we developed rhDSL, a novel soluble form of Notch ligand Delta-like-1, which contains the DSL domain and the N-terminal sequence of the ligand, and investigated its function in ex vivo expansion of human umbilical cord blood (UCB)-primitive hematopoietic cells. The coding sequence for rhDSL was cloned into a pQE30 vector, and the recombinant rhDSL, fused with a 6× His tag, was expressed in Escherichia coli as inclusion bodies after isopropyl β-d-thiogalactoside induction. After renaturing by dilutions, the protein was purified through anion exchange followed by affinity chromatography. The purity of rhDSL protein was more than 99% with very low endotoxin. In combination with human c-kit ligand, the effect of rhDSL on ex vivo expansion of UCB CD34+ cells was found to be optimal at 1.5 μg/ml of rhDSL. The rhDSL protein might therefore be a potential supplement for the expansion of UCB-primitive hematopoietic cells.

Midkine is a heparin-binding growth factor, which plays important roles in the regulation of cell growth and differentiation. The non-tagged recombinant human midkine (rhMK) is therefore required to facilitate its functional studies of this important growth factor. In the present work, rhMK was expressed in Escherichia coli (E. coli) BL21 (DE3). The expression of midkine was efficiently induced by isopropyl-β-D-thiogalactopyranoside (IPTG). After sonication, midkine was recovered in an insoluble form, and was dissolved in guanidine hydrochloride buffer. Renaturation of the denatured protein was carried out in the defined protein refolding buffer, and the refolded protein was purified using S-Sepharose ion-exchange chromatography. The final preparation of the rhMK was greater than 98% pure as measured by sodium dodecylsulfate-polyacrylamid gel electrophoresis (SDS-PAGE) and reverse phase high performance liquid chromatography (RP-HPLC). The purified rhMK enhanced the proliferation of NIH3T3 cells.

The cellular basis of bone marrow (BM) tissue development and regeneration is mediated through hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). Local interplays between hematopoietic cells and BM stromal cells (BMSCs) determine the reconstitution of hematopoiesis after myelosuppression. Here we review the BM local signals in control of BM regeneration after insults. Hematopoietic growth factors (HGFs) and cytokines produced by BMSCs are primary factors in regulation of BM hematopoiesis. Morphogens which are critical to early embryo development in multiple species have been added to the family of HSCs regulators, including families of Wnt proteins, Notch ligands, BMPs, and Hedgehogs. Global gene expression analysis of HSCs and BMSCs has begun to reveal signature groups of genes for both cell types. More importantly, analysis of global gene expression coupled with biochemical and biological studies of local signals during BM regeneration have strongly suggested that HGFs and cytokines may not be the primary local regulators for BM recovery, rather chemokines (SDF-1, FGF-4) and angiogenic growth factors (VEGF-A, Ang-1) play instructive roles in BM reconstitution after myelosuppression. A new direction of management of BM toxicity is emerging from the identification of BM regenerative regulators.

MIG (monokine induced by IFN-γ) is a CXC-chemokine (CXCL9). It plays important roles in regulation of immune activities, and knowledge of the protein in areas of allograft transplants, autoimmune diseases, and cancer therapy is evolving quickly. The non-tagged recombinant murine MIG (rMuMIG) is therefore required to facilitate the functional studies of this important chemokine. Here we present the use of a bacteria expression system to produce non-tagged rMuMIG. The coding sequence for MIG was cloned into the pET28a (+) vector that was transformed into Escherichia coli BL21 (DE3). Expression of rMuMIG was induced by IPTG. Bacteria inclusion bodies containing the protein were isolated and washed to remove contaminated bacteria proteins, and resolved in Urea buffer. Renaturation of the denatured protein was carried out in the defined protein refolding buffer, and the refolded protein was purified using S-Sepharose cation exchange chromatography. The final preparation of the rMuMIG was more than 99% pure as measured by capillary electrophoresis and SDS–PAGE analysis. The biological activity of rMuMIG was demonstrated in a murine spleen cell chemotaxis assay with ED50 30 ng/ml. Further experiments showed that rMuMIG could inhibit proliferation of mouse bone marrow cells in vivo.

S100A6, as a member of S100 protein family, have biological functions in cell proliferation, differentiation, morphology, cytoskeletal organization and apoptosis. In the last three decades, S100A6 has been caught more and more attention. Here, we introduced a simple and efficient method for producing high-purity recombinant human S100A6 from Escherichia coli culture with low level of endotoxin. We further demonstrated its biological activities for triggering SH-SY5Y cells apoptosis in vitro. These results can facilitate the study of physiological and pathological roles of S100A6 and other members of S100 family proteins.Highlights► We introduced a method of producing recombinant human S100A6 from Escherichia coli. ► The purified rhS100A6 totally matches the native human protein without tag. ► The purified rhS100A6 had biological activities and low endotoxin level.

Monokine induced by IFN-γ (Mig) is a member of CXC-chemokines and recruits T-lymphocytes to activate the immune response. In recent years, it has raised much interest in the areas of autoimmune disease and allograft rejection, as the production of recombinant human Mig (rHuMig) would be of considerable significance for both research and potential clinical use. Here we report the expression, preparation and characterization of non-tagged recombinant human Mig (rHuMig) using a prokaryotic expression system. Following expression in Escherichia coli (E. coli) BL21, the 103 amino acid residue of rHuMig was purified from bacteria inclusion bodies with a one-step S-Sepharose cation exchange chromatography. The product was immunologically characterized via Western blot and its purity was determined via SDS–PAGE and silver staining to be above 99%, with an endotoxin level <0.5 EU/μg via a chemotaxis assay, rHuMig demonstrated chemotactic activity on mouse spleen lymphocytes with an ED50 of 15 ng/mL. Additionally, using a proliferation assay, rHuMig significantly inhibited proliferation of the human bladder cell line T24. In vivo experiments revealed that rHuMig could inhibit mouse bone marrow mononuclear cells cycling into the S-phase and reduced intestinal cell proliferation. Our results demonstrate that rHuMig is fully functional in the mouse model.Highlights► We expressed and purified recombinant human CXCL9/Mig with an Escherichia coli expression system. ► The process is easy, fast and cost effective. ► The product is of high purity and low level of endotoxin. ► The product is of high bio-activity in vivo and in vitro. ► We compared the functions of human Mig in comparison with murine Mig in the mouse model.

Using mouse gene expression microarray analysis, we earlier obtained dynamic profiles of whole genome expression in the CCl4-induced liver injury mouse model. CXCL14 expression was increased in the liver injury phase and returned to normal after liver regeneration suggesting its involvement in the liver injury or regeneration regulation. The role of CXCL14 in liver injury was investigated. The dynamic of CXCL14 transcription was analyzed in CCl4-induced mouse liver damage by qRT-PCR. Plasmid mediated CXCL14 overexpression and antibody neutralization of endogenous CXCL14 were used to demonstrate its effects and mechanisms on CCl4-induced liver injury and acute liver failure. We showed that CXCL14 expression was immediately upregulated post CCl4 injection with a dose-dependent response. CXCL14 over-expression aggravated CCl4-induced liver injuries, evidenced by enhanced acidophilic change and necrosis of hepatocyte, increased fat deposition in hepatocytes (P < 0.01), and inhibited hepatocyte proliferation (P < 0.01). On the contrary, anti-CXCL14 antibody treatment reduced the severity of CCL4-induced liver injuries Significant reductions in hepatic necrosis area (P < 0.05), the liver fat deposition (P < 0.01), and the lipid peroxidation measured by serum MDA (P < 0.05) were observed. Importantly, the antibody treatment reduced the mouse mortality caused by CCl4-induced liver failure (P < 0.05). The data suggest that CXCL14 and its receptor present potential targets for the treatment of liver diseases.