Cells were recovered in 1 mL of pre-warmed erythroid differentiation media
July 23, 2021
Cells were recovered in 1 mL of pre-warmed erythroid differentiation media. Erythroid differentiation Erythroid differentiation was performed as previously described . the original. The video spans from 4 min to 12 min following MBS induction.(MP4) pone.0080403.s003.mp4 (7.4M) GUID:?280DC05E-EE71-4B72-8CAB-EF00AEBEF07D Abstract The ultimate goal of gene therapy for Eucalyptol sickle cell anemia (SCA) is an improved phenotype for the patient. In this study, we utilized bone marrow from a sickle cell patient as a model of disease Eucalyptol in an setting for the hyperactive transposon gene therapy system. We demonstrated that mature sickle red blood cells containing hemoglobin-S and sickling in response to metabisulfite can be generated from SCA bone marrow. These cells showed the characteristic morphology and SF1 kinetics of hemoglobin-S polymerization, which we quantified using video microscopy and imaging cytometry. Using video assessment, we showed that delivery of an IHK-T87Q antisickling globin gene by via nucleofection improves metrics of sickling, decreasing percent sickled from 53.2 2.2% to 43.9 2.0%, increasing the median time to sickling from 8.5 to 9.6 min and decreasing the maximum rate of sickling from 2.3 x 10-3 sickling cells/total cells/sec in controls to 1 1.26 x 10-3 sickling cells/total cells/sec in the IHK-T87Q-globin group (< 0.001). Using imaging cytometry, the percentage of elongated sickled cells decreased from 34.8 4.5% to 29.5 3.0% in control versus treated (< 0.05). These results support the potential use of as a clinical gene therapy vector and provide a useful tool for studying sickle red blood cells transposon system (SB) is a nonviral means to deliver a potentially therapeutic transgene [5-7]. First developed more than a decade ago from transposon fossils in the salmonid genome, the system has undergone major improvements, and has demonstrated significant utility in modifying HSCs, most recently using a hyperactive variant termed SB100X [7-11]. The system delivers a transposon, a transgene flanked by a pair of inverted repeats, which is inserted into the genome at random TA-dinucleotides via the transposase that is co-delivered with the transposon. The favorable insertion profile of relative to viruses and the persistent Eucalyptol issues of oncogenesis and clonal expansion in viral therapies make an attractive candidate to increase safety in integrating gene therapy vectors [12-17]. Recently, transplantation trials in humans and numerous animal studies have shown that complete correction or replacement of the hematopoietic stem cell pool or correction of the S point mutation itself are not required to provide therapeutic benefits [18-20]. Given these encouraging trials and the natural history of sickle cell trait, we sought to introduce a competing anti-sickling globin gene to HSCs to test for potential phenotypic correction. The most definitive studies of correction in terms of sickling phenotype have been in animals; however, there are inherent limitations in establishing the safety and efficacy of the correction by extrapolating from mouse models to humans. Several developments have allowed more human versions of the disease to be studied at a level of detail not possible in sickle cell patients. Principally, the development of erythroid differentiation protocols for human CD34+ cells allows for mature red blood cells to be produced to deliver an erythroid-specific IHK-driven hybrid gene to express -globin in erythroid cell lines and the mature erythroid progeny of transduced CD34+ cells from normal donors [24,25]. The 1 kb erythroid promoter IHK can provide high-level expression of -globin in hematopoietic cells and is composed of the intron 8 strong erythroid enhancer, the HS-40 core element upstream from the -globin gene, and the promoter . Fetal hemoglobin and modified hemoglobins have a greater ability to prevent sickling pathology than native -globin. In addition the modified -globin derivative T87Q, which has anti-sickling properties, has been used in an ongoing human trial for -thalassemia as well as in this study to maximize potential benefits of an delivered IHK transgene [12,27]. In this study, we show how mature red blood cells derived from S/S CD34+ cells display the characteristic sickling morphology upon deoxygenation with metabisulfite and the ability of IHK-T87Q-globin to improve this measure of disease pathophysiology. We have adapted imaging cytometry and videography as methods of assessing this phenomenon. These results show the potential clinical utility of IHK--globin-based gene therapy for SCA and a novel method for studying changes in red blood cell morphology in response to gene therapy. Results.