title: Cytoprotective effect of recombinant human erythropoietin produced in transgenic tobacco plants.
abstract: Asialo-erythropoietin, a desialylated form of human erythropoietin (EPO) lacking hematopoietic activity, is receiving increased attention because of its broader protective effects in preclinical models of tissue injury. However, attempts to translate its protective effects into clinical practice is hampered by unavailability of suitable expression system and its costly and limit production from expensive mammalian cell-made EPO (rhuEPO(M)) by enzymatic desialylation. In the current study, we took advantage of a plant-based expression system lacking sialylating capacity but possessing an ability to synthesize complex N-glycans to produce cytoprotective recombinant human asialo-rhuEPO. Transgenic tobacco plants expressing asialo-rhuEPO were generated by stably co-expressing human EPO and β1,4-galactosyltransferase (GalT) genes under the control of double CaMV 35S and glyceraldehyde-3-phosphate gene (GapC) promoters, respectively. Plant-produced asialo-rhuEPO (asialo-rhuEPO(P)) was purified by immunoaffinity chromatography. Detailed N-glycan analysis using NSI-FTMS and MS/MS revealed that asialo-rhuEPO(P) bears paucimannosidic, high mannose-type and complex N-glycans. In vitro cytoprotection assays showed that the asialo-rhuEPO(P) (20 U/ml) provides 2-fold better cytoprotection (44%) to neuronal-like mouse neuroblastoma cells from staurosporine-induced cell death than rhuEPO(M) (21%). The cytoprotective effect of the asialo-rhuEPO(P) was found to be mediated by receptor-initiated phosphorylation of Janus kinase 2 (JAK2) and suppression of caspase 3 activation. Altogether, these findings demonstrate that plants are a suitable host for producing cytoprotective rhuEPO derivative. In addition, the general advantages of plant-based expression system can be exploited to address the cost and scalability issues related to its production.
authors.affiliation: Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, North Carolina, United States of America.
authors.forename: Farooqahmed S
authors.initials: FS
authors.lastname: Kittur
authors.forename: Mamudou
authors.initials: M
authors.lastname: Bah
authors.forename: Stephanie
authors.initials: S
authors.lastname: Archer-Hartmann
authors.forename: Chiu-Yueh
authors.initials: CY
authors.lastname: Hung
authors.forename: Parastoo
authors.initials: P
authors.lastname: Azadi
authors.forename: Mayumi
authors.initials: M
authors.lastname: Ishihara
authors.forename: David C
authors.initials: DC
authors.lastname: Sane
authors.forename: Jiahua
authors.initials: J
authors.lastname: Xie
mesh_terms: D000818:Animals; D053148:Caspase 3 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D019610:Cytoprotection; D004921:Erythropoietin / Q000096:biosynthesis* / Q000737:chemistry / Q000494:pharmacology*; D015870:Gene Expression; D023061:Gene Order; D005822:Genetic Vectors; D006031:Glycosylation; D006801:Humans; D051379:Mice; D009474:Neurons / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D030821:Plants, Genetically Modified; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000494:pharmacology*; D019311:Staurosporine / Q000494:pharmacology; D053719:Tandem Mass Spectrometry; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D004921:Erythropoietin; D053148:Caspase 3; D019311:Staurosporine