RESUMO
OBJECTIVES: To develop a novel thrombopoietin (TPO) analog by fusing the tandem TPO mimetic peptide (TMP-TMP) to human serum albumin (HSA) and performing functional expression of recombinant fusion protein HSA-TMP-TMP. RESULTS: After optimizing the fusion orientation in shake-flask culture, HSA-TMP-TMP was expressed at 0.4 g/l in Pichia pastoris grown in a 20 l bioreactor, during which pH was controlled at 5 by addition of NH4OH and citric acid. The fusion protein significantly activated signal transducer and activator of transcription-mediated transcription in TPO receptor-dependent manner, which was demonstrated by a luciferase reporter assay. Following subcutaneous administration, HSA-TMP-TMP effectively stimulated the platelet production in healthy mice in a dose-dependent manner. CONCLUSION: Successful expression of HSA-TMP-TMP fusion protein in P. pastoris was achieved and the recombinant HSA-TMP-TMP is a promising TPO analog.
Assuntos
Expressão Gênica , Peptídeos/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Albumina Sérica/metabolismo , Animais , Reatores Biológicos , Humanos , Concentração de Íons de Hidrogênio , Injeções Subcutâneas , Camundongos , Peptídeos/genética , Pichia/genética , Pichia/metabolismo , Receptores de Trombopoetina/metabolismo , Proteínas Recombinantes de Fusão/genética , Albumina Sérica/genética , Resultado do TratamentoRESUMO
Three new iridoids, valejatanins A-C (1-3), and one new natrual iridoid (4), together with four known sesquiterpenoids (5-8), were isolated from the roots of Valeriana jatamansi Jones. Compounds 3 and 4 are C(4)-epimers. Their structures were elucidated by extensive spectroscopic analysis (IR, HRESIMS, 1D and 2D NMR) and by comparison of their NMR data with those of related compounds. The absolute configuration of 5 was determined for the first time by single-crystal X-ray diffraction analysis with Cu-Kα irradiation. The cytotoxic activities of all compounds were evaluated against HT29, K562 and B16 cancer cell lines in vitro by MTT assay. Valejatanin A (1) showed noteworthy cytotoxic activities with IC50 values of 22.17, 15.26, 3.53µg/mL against three cancer cell lines. The antibacterial activities of all compounds against bacteria were tested in vitro. Compound 6 exhibited antibacterial activities against Staphylococcus aureus and Pseudomonas aeruginosa.