[Show abstract][Hide abstract] ABSTRACT: We report the adaption of the new Crispr/Cas9 system to disrupt the gene encoding FUT8, an α-1,6-fucosyltransferase that directs fucose addition to derived antibody Fc region Asn 297, in Chinese hamster ovary (CHO) cells. Compared to previously reported homologous recombination (HR) or Zinc finger nucleases (ZFNs) applications in CHO cells, Crispr/Cas9 demonstrated higher targeting efficiency and easier customization. FUT8 disruptive clones (FUT8-/-) were obtained within 3 weeks at indel frequencies ranged from 9% to 25%, which could be enhanced to 52% with Lens culinaris agglutinin (LCA) selection. Based on the lectin blot method, the derived FUT8-/- clone had the ability producing defucosylated therapeutic monoclonal antibody with no detrimental effects on cell growth, viability, or product quality. The clone had the potential of industrial application for therapeutic antibodies manufacturing. We have demonstrated functionally that a gene related to product synthesis could be mutated using Crispr/Cas9 technology and consequently the glycan profile of expressed monoclonal antibody was alternated. We believe that with its robustness and effectiveness, Crispr/Cas9 method can be widely applicable in cell line development leading to higher productivity and better quality of monoclonal antibodies and other biological therapeutics.This article is protected by copyright. All rights reserved
Engineering in Life Sciences 07/2015; 15(6). DOI:10.1002/elsc.201400218 · 2.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose:
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.
Journal of Cancer Research and Clinical Oncology 11/2014; 141(6). DOI:10.1007/s00432-014-1869-y · 3.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chemokines have been shown to play an important role in the pathogenesis of pancreatitis, but the role of chemokine CXCL9 in pancreatitis is poorly understood. The aim of this study was to investigate whether CXCL9 was a modulating factor in chronic pancreatitis. Chronic pancreatitis was induced in Sprague-Dawley rats by intraductal infusion of trinitrobenzene sulfonic acid (TNBS) and CXCL9 expression was assessed by immunohistochemistry, Western blot analysis and enzyme linked immunosorbent assay (ELISA). Recombinant human CXCL9 protein (rCXCL9), neutralizing antibody and normal saline (NS) were administered to rats with chronic pancreatitis by subcutaneous injection. The severity of fibrosis was determined by measuring hydroxyproline in pancreatic tissues and histological grading. The effect of rCXCL9 on activated pancreatic stellate cells (PSCs) in vitro was examined and collagen 1α1, TGF-β1 and CXCR3 expression was assessed by Western blot analysis in isolated rat PSCs. Chronic pancreatic injury in rats was induced after TNBS treatment and CXCL9 protein was markedly upregulated during TNBS-induced chronic pancreatitis. Although parenchymal injury in the pancreas was not obviously affected after rCXCL9 and neutralizing antibody administration, rCXCL9 could attenuate fibrogenesis in TNBS-induced chronic pancreatitis in vivo and exerted antifibrotic effects in vitro, suppressing collagen production in activated PSCs. In conclusion, CXCL9 is involved in the modulation of pancreatic fibrogenesis in TNBS-induced chronic pancreatitis in rats, and may be a therapeutic target in pancreatic fibrosis.
[Show abstract][Hide abstract] ABSTRACT: Alterations in gene expression after chemotherapy may potentially help to identify mediators that induce suppression or regeneration in bone marrow. This paper reports our observation that the expression of the chemokine monokine induced by IFN-γ (Mig) and its receptor CXCR3 was significantly activated in mice after treatment with the chemotherapeutic agent 5-fluorouracil (5-FU). The neutralization of antibodies against the activated Mig increased the survival rate and accelerated BM recovery after chemotherapy. In addition, elevation of Mig plasma levels after 5-FU treatment corresponded with increased mortality. The cell cycle-inhibiting effect of the prophylactic administration of Mig protected hematopoietic progenitor cells (HPCs) from 1-β-d-arabinofuranosylcytosine in spleen colony assays and enhanced the irradiated recipients' survival. In CXCR3(-/-) mice, Mig did not propagate BM suppression, indicating that the suppressive effect of Mig is dependent on CXCR3. On the one hand, Mig stimulated p70 S6K and Erk1/2 pathways in mesenchymal stroma cells, inhibiting mesenchymal stroma cell-dependent HPC expansion. Moreover, Mig suppressed the STAT5 pathway in HPCs, inhibiting leukocyte differentiation. Our results strongly suggest that Mig contributes to the acute lethal toxicity arising from 5-FU administration. Neutralization of Mig may offer new strategies to alleviate BM toxicity with potentially dramatic implications for chemotherapy.
[Show abstract][Hide abstract] ABSTRACT: Acute pancreatitis is a common disease, which is divided into mild pancreatitis and severe pancreatitis. For the latter, a systemic inflammatory response may occur and lead to distant organ damage and the development of multiple organ dysfunction syndrome (MODS), which accounts for significant morbidity and mortality in humans. Chemokines and their receptors are being believed to play a pivotal role in the pathogenesis of acute pancreatitis. Chemokine receptor CXCR3 is reported to be involved in acute tissue injury, for example acute lung injury induced by cigarette smoking, but its role in acute pancreatitis is not yet known. In this study, two animal models of acute pancreatitis (cerulein- and arginine-induced pancreatitis) were applied in CXCR3⁻/⁻ mice and wild-type mice, in order to explore the role of CXCR3 in acute pancreatitis. Serum amylase, lipase and histological observations revealed that CXCR3 knockout did not affect the severity of acute pancreatitis. However, edema and inflammatory cell infiltrate in the lung tissue were attenuated in CXCR3⁻/⁻ mice when acute pancreatitis was induced. In conclusion, chemokine receptor CXCR3 is not involved in acute pancreatic injury, but has a connection with acute pancreatitis-associated lung injury. Acute pulmonary injury is attenuated in CXCR3 knockout mice in experimental acute pancreatitis.
[Show abstract][Hide abstract] ABSTRACT: 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 <0.5EU/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.
Protein Expression and Purification 03/2012; 82(1):205-11. DOI:10.1016/j.pep.2011.12.009 · 1.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chemotherapy induced intestinal mucositis is still an unmet medical problem. 5-fluorouracil (5-Fu), a chemotherapy drug, was used to create the animal model of mucositis. Global gene expression array was applied to identify genetic signals involved in the pathogenesis of mucositis. Interleukin 1 receptor antagonist (IL-1Ra) was one of the candidates with the characteristic gene expression profile. Its temporal expression pattern correlated to the damage and regeneration phase of the small intestine after a single injection of 5-Fu to mice. Administration of recombinant IL-1Ra to the mouse model of intestinal mucositis induced by 5-Fu demonstrated its therapeutic effects to the symptoms and pathology of the disease. The IL-1Ra treatment reduced the acute lethality, accelerated their body weight recovery, and eliminated severe diarrhea. The symptomatic benefits were supported by the pathological benefits, in which the mice treated with IL-1Ra has less damage and faster recovery of the structure integrity of their small intestine than that of the mice treated with vehicle control. To deliver the therapeutics to the unmet medical condition, further mechanism and translational studies of IL-1Ra in the settings of chemotherapy induced intestinal mucositis are warranted.
[Show abstract][Hide abstract] ABSTRACT: Cyclophosphamide is a cytotoxic chemotherapy drug that causes severe damages to hematopoietic and gastrointestinal systems. The aim of this study is to evaluate the protective effects of recombinant human interleukin-1 receptor antagonist (rhIL-1Ra) on chemotherapy-induced mucositis (CIM) in a murine model of cyclophosphamide chemotherapy.
In single chemotherapy models, equal numbers of gender-matched Balb/c mice were administered intraperitoneal injections of rhIL-1Ra at a dose of 1 mg/kg/day or vehicle for 5 continuous days, followed by single intraperitoneal injection of cyclophosphamide at doses of 100, 300, 400 or 550 mg/kg. In multiple cycles of chemotherapy models, mice were administered rhIL-1Ra or vehicle for 5 days, followed by cyclophosphamide injection at a dose of 300 mg/kg. The course has been repeated for 2 or 3 times with a 1-month break in between. In continuous chemotherapy models, mice were administered rhIL-1Ra or vehicle for 5 days, followed by cyclophosphamide injections at doses of 150 or 200 mg/kg/day for 3 days. Body weight and diarrhea were observed in each model. Intestinal morphology was observed in mice received 300 or 400 mg/kg cyclophosphamide chemotherapy.
CIM was induced by cyclophosphamide in a dose-dependent manner. RhIL-1Ra attenuated CIM with reduced body weight loss, diarrhea, intestinal injuries and mortality after CY chemotherapy.
The pretreatment with rhIL-1Ra effectively protected murine gastrointestinal system from clinically relevant cyclophosphamide regimens. The identification of these protective effects of rhIL-1Ra highlights clinical values of this protein for the prevention of CIM.
Cancer Chemotherapy and Pharmacology 06/2011; 67(6):1445-53. DOI:10.1007/s00280-010-1439-1 · 2.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The identification of soluble factors involved in stem cell renewal is a major goal in the assessment of the BM niche. We have previously shown that human endothelial cell (EC) supernatants can induce the proliferation of hematopoietic progenitor cells (HPCs), especially after stimulation with IL-1β. To identify new potential growth factors, we compared the expression profile of IL-1β-stimulated ECs over 4, 8 and 16 h with non-stimulated ECs using oligonucleotide microarrays covering more than 46,000 transcripts. Most significant changes were detected after 4 h. Utilization of Gene Ontology annotation for the stimulated EC transcriptome indicated multiple upregulated genes encoding extracellular proteins with a cell-cell signaling function. Using flow cytometry, delta, colony and cobblestone assays, we assessed the proliferative capacities of 11 gene products, i.e. IL-8, IL-32, FGF-18, osteoprotegerin, Gro 1-3, ENA78, GCP-2, CCL2 and CCL20, which are not known to induce HPC expansion. Notably, IL-32 and to a lesser degree osteoprotegerin and Gro 3 significantly induced the proliferation of HPCs. Furthermore, IL-32 attenuated chemotherapy-related BM cytotoxicities by increasing the number of HPCs in mice. Our findings confirm that the combination of microarrays and gene annotation helps to identify new hematopoietic growth factors.
European Journal of Immunology 06/2011; 41(6):1774-86. DOI:10.1002/eji.201040986 · 4.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chemotherapy-induced intestinal mucositis is still an unmet medical problem. 5-Fluorouracil (5-Fu), a chemotherapy drug, was used to create the animal model of mucositis. Global gene expression array was applied to identify genetic signals involved in the pathogenesis of mucositis. Interleukin 1 receptor antagonist (IL-1Ra) was one of the candidates with the characteristic gene expression profile. Its temporal expression pattern correlated to the damage and regeneration phase of the small intestine after a single injection of 5-Fu to mice. Administration of recombinant IL-1Ra to the mouse model of intestinal mucositis induced by 5-Fu demonstrated its therapeutic effects to the symptoms and pathology of the disease. The IL-1Ra treatment reduced the acute lethality, accelerated their body weight recovery, and eliminated severe diarrhea. The symptomatic benefits were supported by the pathological benefits, in which the mice treated with IL-1Ra had less damage and faster recovery of the structure integrity of their small intestine than that of the mice treated with vehicle control. To deliver the therapeutics to the unmet medical condition, further mechanism and translational studies of IL-1Ra in the settings of chemotherapy-induced intestinal mucositis are warranted.
[Show abstract][Hide abstract] ABSTRACT: Wnt signaling pathway plays important roles in the biology of stem cells in maintaining their self-renewal property. Glycogen synthase kinase-3 (GSK-3) inhibitors, the Wnt signaling agonists, maintain the pluripotency of embryonic stem cells. We report here that a synthetic GSK-3 inhibitor, 6-bromoindirubin-3'-oxime (BIO), showed opposite effects on the expansion of human primitive hematopoietic cells isolated from umbilical cord blood (UCB). In combination with human c-kit ligand (KL), BIO at low concentration (0.2 μM) enhanced the expansion of UCB CD34+ cells, which was BIO structure and exposure time dependent; however, at high concentration (2 μM) it inhibited the expansion of the cells. Furthermore, hematopoietic stem cells (HSCs) were exhausted when the UCB CD34+ cells were exposed to 0.2 μM BIO and KL longer than 2 days. In conclusion, the use of BIO in expansion of UCB HSCs remains a significant challenge.
[Show abstract][Hide abstract] ABSTRACT: Regenerating gene (Reg) IV is a newly discovered member of the regenerating gene family belonging to the calcium (C-type) dependent lectin superfamily. Reg IV is highly expressed in the gastrointestinal tract and markedly up-regulated in colon adenocarcinoma, pancreatic cancer, gastric adenocarcinoma, and inflammatory bowel disease. However, the physiological and pathological functions of Reg IV are largely unknown, partly due to the limited access of the bioactive protein. We report here the first expression and purification of Reg IV proteins using a prokaryotic system. Human Reg IV was expressed in Escherichia coli as an insoluble protein which was identified in the fraction of inclusion body after ultrasonication of the bacteria. After the protein aggregate was solubilized by guanidine-HCl, it was refolded by sucrose and arginine-assisted procedures and purified using cation-exchange chromatography. The protein identity and purity of the final preparation were confirmed by analysis of the protein mass and immune specificity in SDS-PAGE, Western blotting, and HPLC assay. The biological activity of the protein was determined by the HCT116 and HT29 cell proliferation assays. The highly purified bioactive human Reg IV should aid in further characterization of its physiological and pathological functions.
Protein Expression and Purification 09/2009; 69(2):186-90. DOI:10.1016/j.pep.2009.07.018 · 1.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chemerin is a novel chemokine that binds to the G protein-coupled receptor (GPCR) ChemR23, also known as chemokine-like receptor 1 (CMKLR1). It is secreted as a precursor and executes pro-inflammatory functions when the last six amino acids are removed from its C-terminus by serine proteases. After maturation, Chemerin attracts dendritic cells and macrophages through binding to ChemR23. We report a new method for expression and purification of mature recombinant human Chemerin (rhChemerin) using a prokaryotic system. After being expressed in bacteria, rhChemerin in inclusion bodies was denatured using 6M guanidine chloride. Soluble rhChemerin was prepared by the protein-specific renaturation solution under defined conditions. It was subsequently purified using ion-exchange columns to more than 95% purity with endotoxin level <1.0 EU/microg. We further demonstrated its biological activities for attracting migration of human dendritic cells and murine macrophages in vitro using established chemotaxis assays.
Protein Expression and Purification 07/2009; 69(2):153-8. DOI:10.1016/j.pep.2009.07.013 · 1.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 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 6x His tag, was expressed in Escherichia coli as inclusion bodies after isopropyl beta-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 microg/ml of rhDSL. The rhDSL protein might therefore be a potential supplement for the expansion of UCB-primitive hematopoietic cells.
[Show abstract][Hide abstract] ABSTRACT: 5-Fluouracil (5-Fu) targeting of cycling hematopoietic cells results in bone marrow (BM) suppression. Interleukin 1 receptor antagonist (IL-1Ra) is a cytokine that competitively blocks the binding of interleukin 1 (IL-1) to its receptor. Unlike the supporting role of IL-1 less is known for the role of IL-1Ra in hematopoiesis. Here, we demonstrate that IL-1Ra expression in BM cells and in circulation was elevated temporarily during 5-Fu-induced myelosuppression. Exogenous IL-1Ra administered to normal mice reversibly inhibited cycling status of BM cells, and reduced the numbers of BM cells including colony-forming progenitor cells, white blood cells (WBCs), and platelets in a dosage-dependent and time-dependent fashion. Due perhaps to its reversible suppression of the cell cycle progression of BM cells, pretreatment of normal mice with exogenous IL-1Ra reduced the acute lethal toxicity and BM suppression of 5-Fu, and accelerated the recoveries of BM cells and platelets following 5-Fu treatment. Pretreatment with IL-1Ra offers a new promising strategy to alleviate the BM toxicity of chemotherapy in clinical settings.
[Show abstract][Hide abstract] ABSTRACT: MIG (monokine induced by IFN-gamma) 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.
Protein Expression and Purification 10/2007; 55(1):132-8. DOI:10.1016/j.pep.2007.04.004 · 1.70 Impact Factor