SummaryThe current study aimed to understand the developmental mechanisms regulating bud tip progenitor cells in the human fetal lung, which are present during branching morphogenesis, and to use this information to induce a bud tip progenitor-like population from human pluripotent stem cells (hPSCs) in vitro. We identified cues that maintained isolated human fetal lung epithelial bud tip progenitor cells in vitro and induced three-dimensional hPSC-derived organoids with bud tip-like domains. Bud tip-like domains could be isolated, expanded, and maintained as a nearly homogeneous population. Molecular and cellular comparisons revealed that hPSC-derived bud tip-like cells are highly similar to native lung bud tip progenitors. hPSC-derived epithelial bud tip-like structures survived in vitro for over 16 weeks, could be easily frozen and thawed, maintained multilineage potential, and successfully engrafted into the airways of immunocompromised mouse lungs, where they persisted for up to 6 weeks and gave rise to several lung epithelial lineages.
This study demonstrated that TLDG has several advantages over LADG including smaller wounds, less invasiveness, and better feasibility of a secure ablation. The TLDG procedure yields safe anastomosis independently of the patient's constitution or the location of the cancer. Therefore, TLDG is considered to be a useful technique for patients with gastric cancer.
Our surgical outcomes were acceptable in relation to other published results and the prognosis was favorable. Thus, esophageal reconstruction using the ileum and right colon is useful for patients with esophageal cancer for whom the stomach is not available. We currently perform colon interposition with microvascular anastomoses for grafts via the subcutaneous route to increase the safety of this operation.
SummaryThe bud tip epithelium of the branching mouse and human lung contains multipotent progenitors that are able to self-renew and give rise to all mature lung epithelial cell types. The current study aimed to understand the developmental signaling cues that regulate bud tip progenitor cells in the human fetal lung, which are present during branching morphogenesis, and to use this information to induce a bud tip progenitor-like population from human pluripotent stem cells (hPSCs) in vitro. We identified that FGF7, CHIR-99021 and RA maintained isolated human fetal lung epithelial bud tip progenitor cells in an undifferentiated state in vitro, and led to the induction of a 3-dimensional lung-like epithelium from hPSCs. 3-dimensional hPSC-derived lung tissue was initially patterned, with airway-like interior domains and bud tip-like progenitor domains at the periphery. Epithelial bud tip-like domains could be isolated, expanded and maintained as a nearly homogeneous population by serial passaging. Comparisons between human fetal lung epithelial bud tip cells and hPSC-derived bud tip-like cells were carried out using immunostaining, in situ hybridization and transcriptome-wide analysis, and revealed that in vitro derived tissue was highly similar to native lung. hPSC-derived epithelial bud tip-like structures survived in vitro for over 16 weeks, could be easily frozen and thawed and maintained multi-lineage potential. Furthermore, hPSC-derived epithelial bud tip progenitors successfully engrafted in the proximal airways of injured immunocompromised NSG mouse lungs, where they persisted for up to 6 weeks and gave rise to several lung epithelial lineages.
Poly(ADP-ribose) glycohydrolase (Parg) is the main enzyme of poly(ADP-ribose) degradation. To understand its structure-and-function relationship, we purified Parg from rat testis 9,740-fold using an improved affinity column; the purified product was a 60 kDa protein. Based on the determined sequences of three peptide fragments, degenerated primers were synthesized and a Parg cDNA comprising 3,974 nucleotides, encoding a 109 kDa protein, was isolated. The 60 kDa Parg purified from rat testes corresponded to the C-terminal half of the 109 kDa deduced peptide. When recombinant rat Parg was expressed as a glutathione S-transferase fusion protein in Escherichia coli, Parg activity was observed for the full-length and C-terminal half proteins but not in for the N-terminal half protein. Taken together, these data indicate that the catalytic domain of Parg is located in the C-terminal half. Further, we newly identified the presence of a potential nuclear export signal in the N-terminal half in addition to the previously reported nuclear localization signals in rat and other mammalian Pargs. Northern blot analysis showed the ubiquitous expression of a single 4.0 kb Parg mRNA in various rat tissues. The findings suggest that the 60 kDa Parg is produced by post-transcriptional processing.
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