Analysis of proteomic profiling of mouse embryonic stem cells derived from fertilized, parthenogenetic and androgenetic blastocysts

Embryonic stem cells (ESCs) are derived from the inner cell mass (ICM) of preimplantation embryos. ESCs exhibit true pluripotency, i.e., the ability to differentiate into cells of all three germ layers in the developing embryo. We used 2-DE MALDI-TOF/TOF to identify differentially expressed proteins among three types of mouse embryonic stem cells (ESCs) derived from ferti-lized, parthenogenetic, and androgenetic (fESC, pESC and aESC, respectively) blastocysts. We detected more than 800 proteins on silver- stained gels of whole protein extracts from each type of ESC. Of these, 52 differentially expressed proteins were identified by the MALDI–TOF/TOF analyzer, including 32 (fESCs vs. pESCs), 28 (fESCs vs. aESCs) and 17 (pESCs vs. aESCs) prominent proteins with significantly higher or lower expression relative to the comparison cells. Among the 32 proteins from fESCs, 12 were significantly increased in expression and 20 were reduced in expression in fESCs com-pared with pESCs. Similarly, 10 of 28 and 8 of 17 proteins were more highly expressed in fESCs and pESCs compared with aESCs, respectively. In contrast, 18 of 28 and 9 of 17 proteins were reduced in expression in fESCs and pESCs compared with aESCs, respectively. Of the eight protein candidates in fESCs, four were in-creased and four were decreased in expression relative to both pESCs and aESCs in the 2-DE analysis. Differential expression of these pro-teins were confirmed by mRNA expression analysis using real time RT-PCR. For three pro-teins, ANXA5, CLIC1 and SRM, Western blot analysis corroborated the expression patterns indicated by the 2-DE results. ANXA5 and CLIC1 were increased in expression and SRM was de-creased in expression in fESCs compared with both pESCs and aESCs. The differentially ex-pressed proteins identified in the present study warrant further investigation towards the goal of their potential application in ESC therapy.

Enhanced apoptosis during early neuronal differentiation in mouse ES cells with autosomal imbalance

Although particular chromosomal syndromes are phenotypicaUy and clinically distinct, the majority of individuals with autosomal imbalance, such as aneuploidy, manifest mental retardation. A common abnormal phenotype of Down syndrome （DS）, the most prevalent autosomal aneuploidy, shows a reduction in both the number and the density of neurons in the brain. As a DS model, we have recently created chimeric mice from ES cells containing a single human chromosome 21. The mice mimicked the characteristic phenotypic features of DS, and ES cells showed a higher incidence of apoptosis during early neuronal differentiation in vitro. In this study, we examined the induction of anomalous early neural development by aneuploidy in mouse ES cells by transferring various human chromosomes or additional mouse chromosomes. Results showed an elevated incidence of apoptosis in all autosome-aneuploid clones examined during early neuronal differentiation in vitro. Further, cDNA microarray analysis revealed a common cluster of down-regulated genes, of which eight known genes are related to cell proliferation, neurite outgrowth and differentiation. Importantly, targeting of these genes by siRNA knockdown in normal mouse ES cells led to enhanced apoptosis during early neuronal differentiation. These findings strongly suggest that autosomal imbalance is associated with general neuronal loss through a common molecular mechanism for apoptosis.

Identifying MicroRNA and mRNA Expression Profiles in Embryonic Stem Cells Derived from Parthenogenetic,Androgenetic and Fertilized Blastocysts

MicroRNAs（miRNAs） are a class of highly conserved small non-coding RNA molecules that play a pivotal role in several cellular functions.In this study,miRNA and messenger RNA（mRNA） profiles were examined by Illumina microarray in mouse embryonic stem cells（ESCs） derived from parthenogenetic,androgenetic,and fertilized blastocysts.The global analysis of miRNA-mRNA target pairs provided insight into the role of miRNAs in gene expression.Results showed that a total of 125 miRNAs and 2394 mRNAs were differentially expressed between androgenetic ESCs（aESCs） and fertilized ESCs（fESCs）,a total of 42 miRNAs and 87 mRNAs were differentially expressed between parthenogenetic ESCs（pESCs） and fESCs,and a total of 99 miRNAs and 1788 mRNAs were differentially expressed between aESCs and pESCs.In addition,a total of 575,5 and 376 miRNA-mRNA target pairs were observed in aESCs vs.fESCs,pESCs vs.fESCs,and aESCs vs.pESCs,respectively.Furthermore,15 known imprinted genes and 16 putative uniparentally expressed miRNAs with high expression levels were confirmed by both microarray and real-time RT-PCR.Finally,transfection of miRNA inhibitors was performed to validate the regulatory relationship between putative maternally expressed miRNAs and target mRNAs. Inhibition of miR-880 increased the expression of Peg3,Dyrklb,and Prrg2 mRNA,inhibition of miR-363 increased the expression of Nfat5 and Soatl mRNA,and inhibition of miR-883b-5p increased Nfat5,Tacstd2,and Ppapdc1 mRNA.These results warrant a functional study to fully understand the underlying regulation of genomic imprinting in early embryo development.