Expression of Recombinant Human Octamer-Binding Transcription Factor 4 in Rice Suspension Cells.

The rice cell suspension culture system is a good way to produce recombinant human proteins, owing to its high biosafety and low production cost. Human Octamer-binding Transcription Factor 4 (Oct4) is a fundamental transcription factor responsible for maintaining human pluripotent embryonic stem cells. Recombinant Oct4 protein has been used to induce pluripotent stem cells. In this study, recombinant Oct4 proteins are produced via a sugar starvation-inducible αAmy3/RAmy3D promoter-signal peptide-based rice recombinant protein expression system. Oct4 mRNAs accumulate in the transgenic rice suspension cells under sugar starvation. The Oct4 recombinant protein is detected in the transgenic rice suspension cells, and its highest yield is approximately 0.41% of total cellular soluble proteins after one day of sugar starvation. The rice cell-synthesized recombinant human Oct4 protein show DNA-binding activity in vitro, which implies that the protein structure is correct for enabling specific binding to the target DNA motif.

Improving pharmaceutical protein production in Oryza sativa.

Application of plant expression systems in the production of recombinant proteins has several advantages, such as low maintenance cost, absence of human pathogens, and possession of complex post-translational glycosylation capabilities. Plants have been successfully used to produce recombinant cytokines, vaccines, antibodies, and other proteins, and rice (Oryza sativa) is a potential plant used as recombinant protein expression system. After successful transformation, transgenic rice cells can be either regenerated into whole plants or grown as cell cultures that can be upscaled into bioreactors. This review summarizes recent advances in the production of different recombinant protein produced in rice and describes their production methods as well as methods to improve protein yield and quality. Glycosylation and its impact in plant development and protein production are discussed, and several methods of improving yield and quality that have not been incorporated in rice expression systems are also proposed. Finally, different bioreactor options are explored and their advantages are analyzed.

Efficient Secretion of Recombinant Proteins from Rice Suspension-Cultured Cells Modulated by the Choice of Signal Peptide.

Plant-based expression systems have emerged as a competitive platform in the large-scale production of recombinant proteins. By adding a signal peptide, αAmy3sp, the desired recombinant proteins can be secreted outside transgenic rice cells, making them easy to harvest. In this work, to improve the secretion efficiency of recombinant proteins in rice expression systems, various signal peptides including αAmy3sp, CIN1sp, and 33KDsp have been fused to the N-terminus of green fluorescent protein (GFP) and introduced into rice cells to explore the efficiency of secretion of foreign proteins. 33KDsp had better efficiency than αAmy3sp and CIN1sp for the secretion of GFP from calli and suspension-cultured cells. 33KDsp was further applied for the secretion of mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF) from transgenic rice suspension-cultured cells; approximately 76%-92% of total rice-derived mGM-CSF (rmGM-CSF) was detected in the culture medium. The rmGM-CSF was bioactive and could stimulate the proliferation of a murine myeloblastic leukemia cell line, NSF-60. The extracellular yield of rmGM-CSF reached 31.7 mg/L. Our study indicates that 33KDsp is better at promoting the secretion of recombinant proteins in rice suspension-cultured cell systems than the commonly used αAmy3sp.

Zafirlukast improves pulmonary function in patients with moderate persistent asthma receiving regular inhaled steroids: a prospective randomized control study.

BACKGROUND: Zafirlukast is a leukotriene receptor antagonist that was invented to treat patients with chronic asthma. METHODS: To evaluate whether the zafirlukast improved the peak expiratory flow rate (PEFR) and clinical symptoms, 31 asthmatic patients with moderate persistent asthma who received regular inhaled corticosteroid were randomly divided into the study group (N = 17). They received the zafirlukast 20 mg bid for 4 weeks, and the control group (N = 14) received a placebo. Daily morning and evening PEFR and St. George's Respiratory Questionnaire (SGRQ) scoring were recorded respectively. The levels of serum IgE and urine leukotriene E4 before and after treatment were measured using enzyme linked immunosorbent assay and enzyme immunoassay kits. RESULTS: In the zafirlukast treated group, the morning PEFR was significantly improved from 314.4 +/- 20.6 to 340.6 +/- 18.3 L/min (N = 17, p < 0.05) after 4 weeks of treatment, while the control group did not show any significant changes. The zafirlukast group had significant improvement in their symptom scores of SGRQ from 48.6 +/- 4.6 to 33.8 +/- 4.7 (N = 17, p < 0.05). However, the placebo did not improve the symptom scores. CONCLUSION: Leukotriene receptor antagonists effectively improved symptoms and benefited lung function for moderate persistent asthmatic patients who had received regular treatments with inhaled steroids.