Human mid-trimester amniotic fluid (stem) cells lack expression of the pluripotency marker OCT4A

Abstract

Expression of OCT4A is one of the hallmarks of pluripotency, defined as a stem cell’s ability to differentiate into all the lineages of the three germ layers. Despite being defined as non-tumorigenic cells with high translational potential, human mid-trimester amniotic fluid stem cells (hAFSCs) are often described as sharing features with embryonic stem cells, including the expression of OCT4A, which could hinder their clinical potential. To clarify the OCT4A status of hAFSCs, we first undertook a systematic review of the literature. We then performed extensive gene and protein expression analyses to discover that neither frozen, nor fresh hAFSCs cultivated in multipotent stem cell culture conditions expressed OCT4A, and that the OCT4A positive results from the literature are likely to be attributed to the expression of pseudogenes or other OCT4 variants. To address this issue, we provide a robust protocol for the assessment of OCT4A in other stem cells.

scRNA-Seq of Cultured Human Amniotic Fluid from Fetuses with Spina Bifida Reveals the Origin and Heterogeneity of the Cellular Content

“…In addition, SOX2 and KLF4 were expressed in specific clusters but did not mark stem cell populations. Our data support the recently published findings that cultured AF cells of a gestational age of 20-24 weeks do not express Oct-4 and Nanog [28] under standard culture conditions (i.e., not in pluripotency-supporting conditions). On the other hand, the pluripotency marker c-Kit, which has been suggested for the isolation of multipotent AF cells, was detected at the protein level in our study, but not in the transcriptome analysis.…”

“…Single-cell profiling detected 13 clusters of cells which were assigned to nine different cell types, based on marker expression. This finding refutes the theory that only two (spindle-shaped and round-shaped [28]) or three (epithelioid, fibroblastic and amniotic [12,33]) cell types exist in cultured AF. Our study also demonstrates that AF cells with epithelial or mesenchymal phenotypes can be derived from more than one fetal tissue; for instance, cells of both placental and renal origin include subtypes of epithelial and of mesenchymal phenotypes, which represent different cell lineages and express distinct markers according to their tissue origin.…”

Small extracellular vesicles secreted from human amniotic fluid mesenchymal stromal cells possess cardioprotective and promigratory potential

“…Compared to their adult counterparts, foetal MSCs possess greater expansion capacity [27] as well as better functional potential than adult MSCs [4,48]. Amniotic fluid represents a rich source of foetal MSC, i.e., amniotic fluid stem cells (AFSCs), which can be harvested without significant ethical concerns during routine amniocenteses [27,28,62]. Both human AFSCs (hAFSCs) and hAFSC-conditioned medium alone were shown to decrease infarct size in a rat model of acute ischaemia-reperfusion injury [9], while hAFSCs are also more effective than adult bone marrow MSCs in promoting capillary formation in vivo [48].…”

Perinatal Derivatives: Where Do We Stand? A Roadmap of the Human Placenta and Consensus for Tissue and Cell Nomenclature

“…The positivity for OCT-4 is still controversial. Maguire and colleagues reported cytoplasmic and nuclear OCT-4 expression by immunostaining, flow cytometry, clonal analysis, qPCR, and dRNA-seq whole genomic profile (Maguire et al, 2013), on the contrary, a recent study demonstrated the opposite, in particular for mid trimester hAFSC (Vlahova et al, 2019). Nevertheless, hAFSC have been easily reprogrammed not only with DNA-integrating systems (Wolfrum et al, 2010;Bertin et al, 2016) but also without any genetic manipulation by means of the histone deacetylase inhibitor, valproic acid (VPA) (Moschidou et al, 2013a,b).…”