ABSTRACT
Cytochrome P450 (CYP) enzymes metabolize numerous endogenous substrates, such as retinoids, androgens, estrogens and vitamin D, that can modulate important cellular processes, including proliferation, differentiation and apoptosis. The aim of this study is to characterize the expression of CYP genes in CD34+ human cord blood hematopoietic stem and early progenitor cells (CBHSPCs) as a first step toward assessment of the potential biological functions of CYP enzymes in regulating the expansion or differentiation of these cells. CD34+ CBHSPCs were purified from umbilical cord blood via antibody affinity chromatography. Purity of CD34+ CBHSPCs was assessed using fluorescence-activated cell sorting. RNA was isolated from purified CD34+ CBHSPCs and total mononuclear cells (MNCs) for RNA-PCR analysis of CYP expression. Fourteen human CYPs were detected in the initial screening with qualitative RT-PCR in CD34+ CBHSPCs. Further quantitative RNA-PCR analysis of the detected CYP transcripts yielded evidence for preferential expression of CYP2R1 in CD34+ CBHSPCs relative to MNCs; and for greater expression of CYP1B1 in MNCs relative to CD34+ CBHSPCs. These findings provide the basis for further studies on possible functions of CYP2R1 and CYP1B1 in CBHSPCs׳ proliferation and/or differentiation and their potential utility as targets for drugs designed to modulate CD34+ CBHSPC expansion or differentiation.
ABSTRACT
Objective To optimize the conditions for enhancing the refolding of a novel recombinant human(rh)endostatin and test the biological activities of refolded endostatin.Methods The partial purified inclusion bodies of rh-endostatin were dissolved with 6 mol/L guanidine-HCl followed by combination of dilution and dialysis of the dissolved endostatin.The refolded endostatin was then purified by cation-exchange chromatography.The biological activities of purified rh-endostatin were assessed by endostatin-specific monoclonal antibody and chick embryo chorioallantoic membrane assay.Results A 46% refolding yield was achieved after optimizing the refolding conditions.The purified endostatin reacted with specific anti-endostatin monoclonal antibody and showed significant inhibition of angiogenesis in chick embryo ehorioallantoic membrane assay.Conclusion The method of highest refolding yield of human endostatin was developed.This optimized method significantly promotes the application of this novel human endostatin to preclinical and clinical studies.
ABSTRACT
This review focus on the perspective of genetic engineering technology in biopharmaceutical field.Four general aspects of genetic engineering are further discussed in this review as following: the separation of macromolecules,PCR,gene chip,and the expression of foreign genes.The large-scale or industrialization of genetic engineering technology in biopharmaceutics is also reviewed.