Archives

  • 2018-07
  • 2018-10
  • 2018-11
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • 2023-01
  • 2023-02
  • 2023-03
  • 2023-04
  • 2023-05
  • 2023-06
  • 2023-07
  • 2023-08
  • 2023-09
  • 2023-10
  • 2023-11
  • 2023-12
  • 2024-01
  • 2024-02
  • 2024-03
  • 2024-04
  • 2024-05

    • The Douay group reported that when adult HSC derived

    2018-11-07

    The Douay group reported that when adult HSC-derived mature erythroblasts were peripherally injected into the donor, at least half could survive in circulation for as long as 26 days (Giarratana et al., 2011). However, these in vitro expanded mature erythroblasts did not accumulate in a specific organ when injected into NOD/SCID mice (Neildez-Nguyen et al., 2002), suggesting that they are not a suitable long-term transplantable cell source for curing erythroblast deficiencies in patients. hPSC-derived early G+34low36− purchase chir99021 highly co-expressed endothelial markers and generated more erythroblasts than G+34−36− cells. These G+34low36− cells may be more efficient in homing to the hematopoietic niche and thus in helping to cure disorders with early erythropoiesis. Some practical mouse models have been established to track and qualify human erythroblasts in vivo (Getman et al., 2014; Ghinassi et al., 2011; Hu et al., 2011). In future, we will transplant hPSC-derived early G+34low36− cells into immunodeficient mice on a large scale to study their behavior in vivo. Upon precise sorting and reculture, hPSC-derived early immature G+34−36− erythroblasts in our co-culture system intrinsically developed into a more mature G+34−36low stage with a high proliferation potential. This demonstrates that the early development and maturation of hPSC-derived erythroblasts can be traced by the co-expression of GPA and CD36. Similar to the maturation pathway of hCB-CD34+ HSPC-derived erythroblasts, expression of CD36 on hPSC-derived erythroblasts was downregulated at the terminal differentiation stage. Our observations provide evidence of a poorly characterized early erythroid developmental stage during hPSC differentiation, typically characterized as G+34−36− cells. CD36 is an integral transmembrane protein with a high affinity for a variety of antibodies. CD36 gene deficiency is much more prevalent in Asian populations than in Caucasians (0%–0.3%) (Tanaka et al., 2001). This deficiency causes platelet refractoriness, post-transfusion thrombocytopenic purpura, neonatal alloimmune thrombocytopenia, and other disorders (Hirano et al., 2003; Neculai et al., 2013; Rac et al., 2007). However, deficiency of CD36 has no effect on development of erythroblasts (Toba et al., 2001). CD36, in our present study, is only an effective co-marker for tracing the developing erythroid lineage cells, a method that has been widely used (Wong et al., 2010; Okumura et al., 1992). The finding that early erythroblasts derived from hPSC/AGM-S3 (H1, KhES-3, and 201B7) were G+36− suggests that a CD36− stage is common in early erythropoiesis from hPSCs. hPSC-derived erythroblasts generated from erythroid bodies (EBs) in vitro seldom express CD36 (Giarratana et al., 2011; Lu et al., 2008). It is unclear whether these hPSC-derived CD36− erythroblasts share immature properties with early erythroblasts in our system or have undergone terminal maturation into a CD36− stage. Similar to hCB-CD34+ HSPC-derived erythroblasts, BFU-Es derived from day-12 co-culture mostly gave rise to CD36+ daughter cells in suspension culture and reached 100% expression of β-globin (data not shown). These findings demonstrate that our co-culture method favors progression to definitive hematopoiesis. On the other hand, EB-derived hematopoietic progenitors do not directly develop to the mature stage. Whether hPSC-derived hematopoietic cells follow a definitive pathway largely depends on their culture environment. The system of EBs co-culture with OP9 is widely used to generate definitive hematopoietic cells from hPSCs. However, because of the unnatural property of OP9 and the artificially sectioned culture steps, this model is not appropriate for the study of the natural progression of human erythropoiesis. In the current co-culture system, undifferentiated hPSCs are cultured with definitive hematopoietic niche-derived AGM-S3 cells. Thus, this approach provides a unique and ideal tool for the analysis of the serial progression and maturation of hPSC-derived erythroblasts. This enables us to further elucidate the mechanisms underlying diseases with early erythropoiesis, particularly by establishing iPSCs from patients such as those with Diamond-Blackfan anemia (Vlachos et al., 2014). Many efforts have also been made for the efficient large-scale manufacture of hPSC-derived erythrocytes (Slukvin, 2010; Olivier et al., 2012; Perugini et al., 2009; Smith et al., 2013; Kurita et al., 2013). Meanwhile, practical solutions for enucleation (Fujimi et al., 2008) and hemoglobin switching (Xu et al., 2012) of erythrocytes developed from hPSCs are required. Our co-culture system developed here may benefit the breaking down of these barriers to generating mature erythrocytes in future clinical applications.