HLA Homozygous Stem Cell Lines Derived from Human Parthenogenetic Blastocysts

Abstract

Individual HLA homozygous parthenogenetic human stem cell (hpSC-Hhom) lines have the potential for cell-based therapy in a significant number of individuals, provided the HLA haplotype is prevalent. We report the successful derivation of four stable hpSC-Hhom lines from both HLA homozygous and HLA heterozygous donors. Of these, the hpSC-Hhom-4 line carries the HLA haplotype found most commonly within the U.S. population, and is shared by different racial groups. These hpSC-Hhom lines demonstrate typical human embryonic stem cell morphology, expressing appropriate stem cell markers and possessing high levels of alkaline phosphatase and telomerase activity. Additionally, injection of these cell lines into immunodeficient animals leads to teratoma formation. G-banded karyotyping demonstrates a normal 46,XX karyotype in lines hpSC-Hhom-1 and hpSC-Hhom-4, and chromosomal anomalies in lines hpSC-Hhom-2 and hpSC-Hhom-3, both derived from the same donor. HLA genotyping of all four hpSC-Hhom lines demonstrates that they are HLA homozygous. Furthermore, in the case of HLA heterozygous donors, the hpSC-Hhom lines inherit the haplotype from only one of the donor's parents. Single-nucleotide polymorphism (SNP) data analysis suggests that hpSC-Hhom lines derived from HLA heterozygous oocyte donors are homozygous throughout the genome as assessed by SNP analysis. The protocol used for deriving these HLA homozygous stem cell lines minimizes the use of animal-derived components, which makes them more appealing for potential clinical application.

Genetic and epigenetic X-chromosome variations in a parthenogenetic human embryonic stem cell line

“…The derivation efficiency was 5.6% (1/18) when calculated from all collected oocytes or 25% (1/4) when calculated from Day 5 blastocysts. The derivation efficiency was similar to those reported in previous reports [6,7]. These cells displayed morphologies and characteristics similar to those of normal hESCs.…”

“…From previous reports, phESCs appear to be less stable than hESCs derived from fertilized embryos. It has been found that two of four HLA homozygous phESC lines have karyotype anomalies [7], and one of the six HLA heterozygous phESC lines is aneuploid [5]. Kim et al [27] also found that SCNT-hES-1 (the first derived phESC line), which was initially thought to be generated from somatic nuclear transfer, lost one of its two X chromosomes and duplicated chromosome 7 after long-term culturing.…”

“…Recently, a few phESC lines were established [4][5][6][7][8]. These cells display self-renewal and multi-differentiation properties similar to those of normal hESCs derived from fertilized embryos [4][5][6][7][8]. Although the biological characterization of phESCs is documented, the genetic and epigenetic behaviors of these cells must still be investigated.…”

Embryonic Stem Cell in the Therapy of Neurodegenerative Diseases

“…The success in iPSCs seems to offer the advantages of hESCs without the ethical and rejection problems, although the iPSCs is not as versatile and plastic as ESCs. Revazova and collegues have established four unique HLAhomozygous human ESCs lines which have a simple genetic profile in the critical areas of the DNA that code for immune rejection, these ES cell lines will not provoke an immune reaction in large segments of the population and could serve to create a stem cell bank as a renewable source of transplantable cells for use in cell therapy to treat degenerative diseases (Revazova et al, 2008). In conclusion, although there is still a long way to go in ESCs replacement therapy to become a clinical reality for AD, PD, HD and ALS, this therapeutic approach is promising for neurodegenerative diseases.…”

Parthenogenetic embryonic stem cells with H19 siRNA-mediated knockdown as a potential resource for cell therapy

“…However, there are serious safety concerns because iPS cells can enter tumorigenesis at a faster rate than the ES cells (2). Parthenogenetic embryonic stem (ESP) cells have been considered as a resource for cell therapy and may reduce immune rejection due to the homozygosity of the major histocompatibility complex (MHC) alleles (3,4). The ESP cells that are derived from unfertilized oocytes have a similar differentiation profiles as the ES cells in many animals, including humans (5), and may avoid the ethical and political concerns encountered when using ES cells that are derived from fertilized oocytes.…”