Liver transplantation is the last resort for liver failure patients. However, due to the shortage of donor organs, bioengineered liver generated from decellularized whole liver scaffolds and induced pluripotent stem cell (iPSC)-derived hepatocytes (iPSC-Heps) is being studied as an alternative approach to treat liver disease. Nevertheless, there has been no report on both the interaction of iPSC-Heps with a liver extracellular matrix (ECM) and the analysis of recellularized iPSC-Heps into the whole liver scaffolds. In this study, we produced porcine iPSC-Heps, which strongly expressed the hepatic markers α-fetoprotein and albumin and exhibited hepatic functionalities, including glycogen storage, lipid accumulation, low-density lipoprotein uptake, and indocyanine green metabolism. Supplementation of ECM from porcine decellularized liver containing liver-derived growth factors stimulated the albumin expression of porcine iPSC-Heps during differentiation procedures. The iPSC-Heps were reseeded into decellularized liver scaffolds, and the recellularized liver was cultured using a continuous perfusion system. The recellularized liver scaffolds were transplanted into rats for a short term, and the grafts expressed hepatocyte markers and did not rupture. These results provide a foundation for development of bioengineered liver using stem cell and decellularized scaffolds.

Human embryonic stem cells (hESCs) expressing pluripotency markers are assumed to possess equipotent developmental potential. However, disparate responses to differentiation stimuli functionally illustrate that hESCs generate a spectrum of differentiated cell types, suggestive of lineage bias. Here, we reveal specific cell surface markers that allow subfractionation of hESCs expressing hallmark markers of pluripotency. By direct de novo isolation of these subsets, we demonstrate that propensities for lineage differentiation are balanced with reduced clonogenic self-renewal. Histone modification marks of gene loci associated with pluripotency versus lineage specificity predicted cell fate potential of these subfractions, thereby supporting the absence of uniform bivalency as a molecular paradigm to describe cell fate determination of pluripotent cells. Our study reveals that cell fate potential is encoded within cells comprising hESC cultures, highlighting them as a means to understand the mechanisms of lineage specification of pluripotent cells.

Human umbilical cord-derived perivascular cells (PVCs) are a recently characterized source of mesenchymal stromal cells that has gained much interest in the field of cellular therapeutics. However, very little is known about the changes in fate potential and restrictions that these cells undergo during gestational development. This study is the first to examine the phenotypic, molecular, and functional properties of first trimester (FTM)-derived PVCs, outlining properties that are unique to this population when compared to term (TERM) counterparts. FTM- and TERM-PVCs displayed analogous mesenchymal, perivascular, and immunological immunophenotypes. Both PVCs could be maintained in culture without alteration to these phenotypes or mesenchymal lineage differentiation potential. Some unique features of FTM-PVCs were uncovered in this study: (1) while the gene signatures of FTM- and TERM-PVCs were similar, key differences were observed, namely, that the Oct4A and Sox17 proteins were detected in FTM-PVCs, but not in TERM counterparts; (2) FTM-PVCs exhibited a greater proliferative potential; and (3) FTM-PVCs were more efficient in their in vitro differentiation toward selective mesenchymal cell types, including the chondrogenic and adipogenic lineages, as well as toward neuronal- and hepatocyte-like lineages, when compared to TERM-PVCs. Both PVCs were able to generate osteocytes and cardiomyocyte-like cells with similar efficiencies in vitro. Overall, FTM-PVCs show more plasticity than TERM-PVCs with regard to fate acquisition, suggesting that a restriction in multipotentiality is imposed on PVCs as gestation progresses. Taken together, our findings support the idea that PVCs from earlier in gestation may be better than later sources of multipotent stromal cells (MSCs) for some regenerative medicine applications.

The Plasmodium vivax reticulocyte-binding protein (RBP) family was identified based on the annotation of adhesive ligands in the P. vivax genome. Reticulocyte-specific interactions with the PvRBPs (PvRBP1 and PvRBP2) were previously reported. Plasmodium falciparum reticulocyte-binding protein homologue 4 (PfRh4, a homologue of PvRBP1) was observed to possess erythrocyte-binding activity via complement receptor 1 on the erythrocyte surface. However, the reticulocyte-binding mechanisms of P. vivax are unclear because of the large molecular mass of PvRBP1 (>326 kDa) and the difficulty associated with in vitro cultivation. In the present study, 34 kDa of PvRBP1a (PlasmoDB ID: PVX_098585) and 32 kDa of PvRBP1b (PVX_098582) were selected from a 30 kDa fragment of PfRh4 for reticulocyte-specific binding activity analysis. Both PvRBP1a and PvRBP1b were found to be localized at the microneme in the mature schizont-stage parasites. Naturally acquired immune responses against PvRBP1a-34 and PvRBP1b-32 were observed lower than PvDBP-RII. The reticulocyte-specific binding activities of PvRBP1a-34 and PvRBP1b-32 were significantly higher than normocyte binding activity and were significantly reduced by chymotrypsin treatment. PvRBP1a and 1b, bind to reticulocytes and that this suggests that these ligands may have an important role in P. vivax merozoite invasion.