Proteomics of Huntington's disease-affected human embryonic stem cells reveals an evolving pathology involving mitochondrial dysfunction and metabolic disturbances.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a mutation in the Huntingtin gene, where excessive (≥ 36) CAG repeats encode for glutamine expansion in the huntingtin protein. Research using mouse models and human pathological material has indicated dysfunctions in a myriad of systems, including mitochondrial and ubiquitin/proteasome complexes, cytoskeletal transport, signaling, and transcriptional regulation. Here, we examined the earliest biochemical and pathways involved in HD pathology. We conducted a proteomics study combined with immunocytochemical analysis of undifferentiated HD-affected and unaffected human embryonic stem cells (hESC). Analysis of 1883 identifications derived from membrane and cytosolic enriched fractions revealed mitochondria as the primary dysfunctional organ in HD-affected pluripotent cells in the absence of significant differences in huntingtin protein. Furthermore, on the basis of analysis of 645 proteins found in neurodifferentiated hESC, we show a shift to transcriptional dysregulation and cytoskeletal abnormalities as the primary pathologies in HD-affected cells differentiating along neural lineages in vitro. We also show this is concomitant with an up-regulation in expression of huntingtin protein in HD-affected cells. This study demonstrates the utility of a model that recapitulates HD pathology and offers insights into disease initiation, etiology, progression, and potential therapeutic intervention.

Cell lines from morphologically abnormal discarded IVF embryos are typically euploid and unaccompanied by intrachromosomal aberrations.

Routine IVF practices result in the discarding of a significant proportion of embryos due to their unsuitability for transfer or cryopreservation. The present study plated clinically unusable human blastocysts to derive cellular outgrowths for aneuploidy studies and genome-wide analysis of DNA copy number variations, and to evaluate their potential as a source for pluripotent stem cells. Just 79 cellular outgrowths were obtained from 1026 abnormal blastocysts (7.7%), reflecting their low developmental potential. Of these, 13 (16.5%) were karyotypically abnormal and included trisomies frequently detected in miscarriages, each of which was uniform (nonmosaic) and the result of meiotic nondisjunction. Evaluation of submicroscopic DNA gains and losses in 10 diploid cellular outgrowths did not identify increased rates of copy number variations. Five of these outgrowths were shown to express pluripotency markers and could be developed into cell lineages representative of the three germ layers. These data suggest that embryos with chromosomal abnormalities resist cell-line derivation, and mosaic aneuploidy produced from mitotic nondisjunction, common in preimplantation embryos, is likely to be diminished or lost under conditions of diploid cell competition. Furthermore, this work demonstrated that abnormal embryos discarded in IVF programmes can provide a valuable source for pluripotent stem cell lines. During IVF, a large proportion of embryos are clinically unsuitable due to abnormal development and these embryos only have a small chance of achieving a pregnancy. Here we used these abnormal embryos to create cell lines for genetic testing and to determine their potential as stem cells. Of the 1026 abnormal embryos used, 79 (7.7%) created cell lines, reflecting their low developmental potential. Of those, only 16.5% had chromosomal anomalies, a much lower number than expected. This included chromosome abnormalities frequently observed in miscarriages, all of which were found in each cell tested (nonmosaic) and originated from the egg or the sperm as opposed to cell division. In-depth testing of 10 normal cell lines for small DNA gains and losses did not reveal an increased frequency of mutations. Furthermore, five of the cell lines were examined for stem cell properties and found to exhibit the hallmark features of stem cells including their ability to make mature cells from different parts of the body. Our data suggest that embryos with abnormal chromosomes resist making cell lines and that abnormalities that arise during cell division are likely to be lost due to competition with normal cells. We also demonstrated that abnormal embryos usually discarded in IVF programmes can provide a valuable source for stem cell lines.

Improved membrane proteomics coverage of human embryonic stem cells by peptide IPG-IEF.

Protein biomarkers are fundamental tools for the characterization of stem cells and for tracking their differentiation and maturation down developmental lineages. Technology development allowing increased coverage of difficult cellular proteomes should allow for the discovery of new and novel membrane protein biomarkers for use by the stem cell research community. The amphipathic and highly hydrophobic nature and relative low abundance of many membrane proteins present significant analytical challenges. These difficulties are amplified when the source material (tissue or cells) is only available in limited quantities (e.g., embryonic stem cells). Recent advances in enrichment for purer membrane fractions, the enzymatic and chemical digestion of membrane proteins in the presence of solvents or chaotropes, and the use of "shotgun" proteomics methodologies have gradually resulted in increased membrane proteome coverage with numbers of predicted integral membrane proteins now in excess of 1000 being routinely reported. We have recently demonstrated the advantages of using peptide isoelectric focusing in the first dimension on immobilized pH gradients (peptide IPG-IEF) followed by reversed phase chromatography and tandem MS to increase membrane proteome coverage. This study looked at achieving a similar level of membrane proteome coverage using modifications to reported methodologies while restricting the number of characterized human embryonic stem cells to 10(7) cells. Two-thousand two-hundred and ninety-two (2292) nonredundant proteins were identified with two or more high accuracy peptide matches from 260 mug of a human embryonic stem cell membrane enriched fraction with a false discovery rate of 0.32%. Gene Ontology (GO) mapping predicted 1279 (44.9%) of this list to be membrane proteins of which 395 proteins were predicted to be derived from the plasma membrane compartment. The TMHMM algorithm predicted 904 integral membrane proteins with up to 16 transmembrane helices. Collectively, we assert that the substantial membrane proteome coverage achieved using these procedures will enable rapid advances in the identification and quantitation of novel membrane proteins as markers of differentiation status and/or genetic mutation from relatively low numbers of cultured embryonic stem cells.

Impaired myogenic development, differentiation and function in hESC-derived SMA myoblasts and myotubes.

Spinal muscular atrophy (SMA) is a severe genetic disorder that manifests in progressive neuromuscular degeneration. SMA originates from loss-of-function mutations of the SMN1 (Survival of Motor Neuron 1) gene. Recent evidence has implicated peripheral deficits, especially in skeletal muscle, as key contributors to disease progression in SMA. In this study we generated myogenic cells from two SMA-affected human embryonic stem cell (hESC) lines with deletion of SMN1 bearing two copies of the SMN2 gene and recapitulating the molecular phenotype of Type 1 SMA. We characterized myoblasts and myotubes by comparing them to two unaffected, control hESC lines and demonstrate that SMA myoblasts and myotubes showed altered expression of various myogenic markers, which translated into an impaired in vitro myogenic maturation and development process. Additionally, we provide evidence that these SMN1 deficient cells display functional deficits in cholinergic calcium signaling response, glycolysis and oxidative phosphorylation. Our data describe a novel human myogenic SMA model that might be used for interrogating the effect of SMN depletion during skeletal muscle development, and as model to investigate biological mechanisms targeting myogenic differentiation, mitochondrial respiration and calcium signaling processes in SMA muscle cells.

Derivation of Huntington Disease affected Genea089 human embryonic stem cell line.

The Genea089 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, carrying Htt gene CAG expansion of 41 repeats, indicative of Huntington Disease. Following ICM outgrowth on inactivated human feeders, karyotype was confirmed as 46, XX by CGH and STR analysis demonstrated a female Allele pattern. The hESC line had pluripotent cell morphology, 91% of cells expressed Nanog, 95% Oct4, 90% Tra1-60 and 100% SSEA4 and gave a PluriTest Pluripotency score of 39.28, Novelty of 1.2. The cell line was negative for Mycoplasma and visible contamination.

Derivation of NEM2 affected human embryonic stem cell line Genea079.

The Genea079 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, carrying compound heterozygous mutations in the NEB gene, exon 55 deletion & c.15110dupA, indicative of Nemaline Myopathy Type 2 (NEM2). Following ICM outgrowth on inactivated human feeders, karyotype was confirmed as 46, XY and STR analysis demonstrated a male Allele pattern. The hESC line had pluripotent cell morphology, 86% of cells expressed Nanog, 95% Oct4, 54% Tra1-60 and 98% SSEA4 and gave a PluriTest Pluripotency score of 30.25, Novelty of 1.21. The cell line was negative for Mycoplasma and visible contamination.

Derivation of NEM2 affected human embryonic stem cell line Genea080.

The Genea080 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, carrying compound heterozygous mutations in the NEB gene, exon 55 deletion & c.15110dupA, indicative of Nemaline Myopathy Type 2 (NEM2). Following ICM outgrowth on inactivated human feeders, karyotype was confirmed as 46, XY and STR analysis demonstrated a male allele pattern. The hESC line had pluripotent cell morphology, 90% of cells expressed Nanog, 95% Oct4, 54% Tra1-60 and 99% SSEA4 and gave a PluriTest Pluripotency score of 32.08, Novelty of 1.3. The cell line was negative for Mycoplasma and visible contamination.

Derivation of Trisomy 21 affected human embryonic stem cell line Genea053.

The Genea053 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, carrying Trisomy 21, indicative of Down Syndrome. Following ICM outgrowth on inactivated human feeders, CGH and STR analysis demonstrated a 47, XY, +21 karyotype and male allele pattern. The hESC line had pluripotent cell morphology and expressed pluripotent cell markers including 83% Nanog positive, 87% Oct4, 88% Tra1-60 and 98% SSEA4. The cell line was negative for Mycoplasma and visible contamination.

Derivation of Genea016 human embryonic stem cell line.

The Genea016 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, through ICM outgrowth on inactivated human feeders. The line showed pluripotent cell morphology and genomic analysis verified a 46, XX karyotype and female Allele pattern through traditional karyotyping, CGH and STR analysis. Pluripotency of Genea016 was demonstrated with 77% of cells expressing Nanog, 95% Oct4, 53% Tra1-60 and 98% SSEA4, a PluriTest Pluripotency score of 28.4, Novelty score of 1.37 and Alkaline Phosphatase activity. The cell line was negative for Mycoplasma and any visible contamination.

Derivation of Genea057 human embryonic stem cell line.

The Genea057 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, through ICM outgrowth on inactivated human feeders. The line showed pluripotent cell morphology and genomic analysis verified a 46, XX karyotype and female allele pattern through traditional karyotyping, CGH and STR analysis. Pluripotency of Genea057 was demonstrated with 97% of cells expressing Nanog, 81% Oct4, 75% Tra1-60 and 97% SSEA4, a PluriTest Pluripotency score of 27.59 and Novelty score of 1.32. The cell line was negative for Mycoplasma and any visible contamination.

Derivation of Genea043 human embryonic stem cell line.

The Genea043 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, through ICM outgrowth on inactivated human feeders. The line showed pluripotent cell morphology and genomic analysis verified a 46, XY karyotype and male allele pattern through traditional karyotyping, CGH and STR analysis. Pluripotency of Genea043 was demonstrated with 92% of cells expressing Nanog, 95% Oct4, 61% Tra1-60 and 99% SSEA4, a PluriTest Pluripotency score of 31.74, Novelty score of 1.2 and Alkaline Phosphatase activity. The cell line was negative for Mycoplasma and any visible contamination.

Derivation of Genea002 human embryonic stem cell line.

The Genea002 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, through ICM outgrowth on inactivated feeders. The line showed pluripotent cell morphology and genomic analysis verified a 46, XY karyotype by CGH and male Allele pattern through STR analysis. Pluripotency of Genea002 was demonstrated with 75% of cells expressing Nanog, 93% Oct4, 83% Tra1-60 and 98% SSEA4, a Pluritest pluripotency score of 24.55, Novelty score of 1.39, teratomas with tissues from all embryonic germ layers and Alkaline Phosphatase activity. The cell line was negative for Mycoplasma and any visible contamination.

Derivation of Genea042 human embryonic stem cell line.

The Genea042 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, through ICM outgrowth on inactivated human feeders. The line showed pluripotent cell morphology and genomic analysis verified a 46, XX karyotype and female allele pattern through traditional karyotyping, CGH and STR analysis. Pluripotency of Genea042 was demonstrated with 81% of cells expressing Nanog, 95% Oct4, 53% Tra1-60 and 97% SSEA4, a PluriTest Pluripotency score of 30.06, Novelty score of 1.24 and Alkaline Phosphatase activity. The cell line was negative for Mycoplasma and any visible contamination.

Derivation of Genea052 human embryonic stem cell line.

The Genea052 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, through ICM outgrowth on inactivated human feeders. The line showed pluripotent cell morphology and genomic analysis verified a 46, XY karyotype and male allele pattern through CGH and STR analysis. Pluripotency of Genea052 was demonstrated with 85% of cells expressing Nanog, 87% Oct4, 60% Tra1-60 and 97% SSEA4, a PluriTest Pluripotency score of 27.21, Novelty score of 1.2 and tri-lineage teratoma formation. The cell line was negative for Mycoplasma and any visible contamination.

Derivation of Genea047 human embryonic stem cell line.

The Genea047 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, through ICM outgrowth on inactivated human feeders. The line showed pluripotent cell morphology and genomic analysis verified a 46, XX karyotype and female allele pattern through traditional karyotyping, CGH and STR analysis. Pluripotency of Genea047 was demonstrated with 88% of cells expressing Nanog, 95% Oct4, 59% Tra1-60 and 99% SSEA4, a PluriTest Pluripotency score of 30.86, Novelty score of 1.23 and tri-lineage teratoma formation. The cell line was negative for Mycoplasma and any visible contamination.

Derivation of human embryonic stem cell line Genea019.

The Genea019 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, through ICM outgrowth on inactivated feeders. The line showed pluripotent cell morphology and genomic analysis verified a 46, XX karyotype, female Allele pattern and unaffected Htt CAG repeat length, compared to HD affected sibling Genea020. Pluripotency of Genea019 was demonstrated with 75% of cells expressing Nanog, 89% Oct4, 48% Tra1-60 and 85% SSEA4, a Pluritest Pluripotency score of 22.97, Novelty score of 1.42, tri-lineage teratoma formation and Alkaline Phosphatase activity. The cell line was negative for Mycoplasma and any visible contamination.

Derivation of Trisomy 21 affected human embryonic stem cell line Genea021.

The Genea021 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, carrying Trisomy 21, indicative of Down Syndrome. Following ICM outgrowth on inactivated human feeders, CGH and STR analyses demonstrated a 47, XY, +21 karyotype and male allele pattern. The hESC line had pluripotent cell morphology, 71% of cells expressed Nanog, 84% Oct4, 23% Tra1-60 and 95% SSEA4, gave a Pluritest Pluripotency score of 21.85, Novelty of 1.42, demonstrated Alkaline Phosphatase activity and tri-lineage teratoma formation. The cell line was negative for Mycoplasma and visible contamination.

Derivation of Huntington Disease affected Genea018 human embryonic stem cell line.

The Genea018 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, carrying Htt gene CAG expansion of 46 repeats, indicative of Huntington Disease. Following ICM outgrowth on inactivated human feeders, karyotype was confirmed as 46, XX by CGH and STR analysis demonstrated a female Allele pattern. The hESC line had pluripotent cell morphology, 75% of cells expressed Nanog, 91% Oct4, 73% Tra1-60 and 96% SSEA4, gave a Pluritest pluripotency score of 31.12, Novelty of 1.45, demonstrated Alkaline Phosphatase activity and tri-lineage teratoma formation. The cell line was negative for Mycoplasma and visible contamination.

Derivation of NEM2 affected human embryonic stem cell line Genea078.

The Genea078 human embryonic stem cell line was derived from a donated, fully commercially consented ART blastocyst, carrying compound heterozygous mutations in the NEB gene, exon 55 deletion & c.15110dupA, indicative of Nemaline Myopathy Type 2 (NEM2). Following ICM outgrowth on inactivated human feeders, karyotype was confirmed as 46, XX and STR analysis demonstrated a female Allele pattern. The hESC line had pluripotent cell morphology, 76% of cells expressed Nanog, 93% Oct4, 67% Tra1-60 and 97% SSEA4 and gave a Pluritest Pluripotency score of 42.18, Novelty of 1.37. The cell line was negative for Mycoplasma and visible contamination.