Kusum Zaveri

Detection, Characterization, and Spontaneous Differentiation In Vitro of Very Small Embryonic-Like Putative Stem Cells in Adult Mammalian Ovary

The present study was undertaken to detect, characterize, and study differentiation potential of stem cells in adult rabbit, sheep, monkey, and menopausal human ovarian surface epithelium (OSE). Two distinct populations of putative stem cells (PSCs) of variable size were detected in scraped OSE, one being smaller and other similar in size to the surrounding red blood cells in the scraped OSE. The smaller 1-3 μm very small embryonic-like PSCs were pluripotent in nature with nuclear Oct-4 and cell surface SSEA-4, whereas the bigger 4-7 μm cells with cytoplasmic localization of Oct-4 and minimal expression of SSEA-4 were possibly the tissue committed progenitor stem cells. Pluripotent gene transcripts of Oct-4, Oct-4A, Nanog, Sox-2, TERT, and Stat-3 in human and sheep OSE were detected by reverse transcriptase-polymerase chain reaction. The PSCs underwent spontaneous differentiation into oocyte-like structures, parthenote-like structures, embryoid body-like structures, cells with neuronal-like phenotype, and embryonic stem cell-like colonies, whereas the epithelial cells transformed into mesenchymal phenotype by epithelial-mesenchymal transition in 3 weeks of OSE culture. Germ cell markers like c-Kit, DAZL, GDF-9, VASA, and ZP4 were immuno-localized in oocyte-like structures. In conclusion, as opposed to the existing view of OSE being a bipotent source of oocytes and granulosa cells, mammalian ovaries harbor distinct very small embryonic-like PSCs and tissue committed progenitor stem cells population that have the potential to develop into oocyte-like structures in vitro, whereas mesenchymal fibroblasts appear to form supporting granulosa-like somatic cells. Research at the single-cell level, including complete gene expression profiling, is required to further confirm whether postnatal oogenesis is a conserved phenomenon in adult mammals.

Proteomic analysis of human follicular fluid: a new perspective towards understanding folliculogenesis.

UNLABELLED Human follicular fluid is a complex body fluid that constitutes the microenvironment of developing follicles in the ovary. Follicular fluid contains a number of proteins that modulate oocyte maturation and ovulation. Information about the protein constituents of follicular fluid may provide a better understanding of ovarian physiology in addition to opening new avenues for investigating ovarian disorders. However, the composition of follicular fluid proteome remains poorly defined. In this study, we carried out SDS-PAGE, OFFGEL and SCX-based separation followed by LC-MS/MS analysis to characterize the proteome of human follicular fluid. We report high confidence identification of 480 proteins, of which 320 have not been described previously in the follicular fluid. The identified proteins belong to diverse functional categories including growth factor and hormones, receptor signaling, enzyme catalysis, defense/immunity and complement activity. Our dataset should serve as a resource for future studies aimed at developing biomarkers for monitoring oocyte and embryo quality, pregnancy outcomes and ovarian disorders. BIOLOGICAL SIGNIFICANCE Proteome analysis of human follicular fluid by multi-pronged approach of protein peptide fractionation revealed 480 proteins with high confidence. The identified protein may facilitate the understanding of folliculogenesis. This protein dataset should serve as a useful resource for development of biomarkers for oocyte quality, in vitro fertilization techniques and female infertility.

Dynamics associated with spontaneous differentiation of ovarian stem cells in vitro

BackgroundRecent studies suggest that ovarian germ line stem cells replenish oocyte-pool in adult stage, and challenge the central doctrine of ‘fixed germ cell pool’ in mammalian reproductive biology. Two distinct populations of spherical stem cells with high nucleo-cytoplasmic ratio have been recently identified in the adult mammalian ovary surface epithelium (OSE) including nuclear OCT-4A positive very small embryonic-like (VSELs) and cytoplasmic OCT-4 expressing ovarian germ stem cells (OGSCs). Three weeks culture of scraped OSE cells results in spontaneous differentiation of the stem cells into oocyte-like, parthenote-like, embryoid body-like structures and also embryonic stem cell-like colonies whereas epithelial cells attach and transform into a bed of mesenchymal cells. Present study was undertaken, to further characterize ovarian stem cells and to comprehend better the process of spontaneous differentiation of ovarian stem cells into oocyte-like structures in vitro.MethodsOvarian stem cells were enriched by immunomagnetic sorting using SSEA-4 as a cell surface marker and were further characterized. Stem cells and clusters of OGSCs (reminiscent of germ cell nests in fetal ovaries), were characterized by immuno-localization for stem and germ cell specific markers and spontaneous differentiation in OSE cultures was studied by live cell imaging.ResultsDifferential expression of markers specific for pluripotent VSELs (nuclear OCT-4A, SSEA-4, CD133), OGSCs (cytoplasmic OCT-4) primordial germ cells (FRAGILIS, STELLA, VASA) and germ cells (DAZL, GDF-9, SCP-3) were studied. Within one week of culture, stem cells became bigger in size, developed abundant cytoplasm, differentiated into germ cells, revealed presence of Balbiani body-like structure (mitochondrial cloud) and exhibited characteristic cytoplasmic streaming.ConclusionsPresence of germ cell nests, Balbiani body-like structures and cytoplasmic streaming extensively described during fetal ovary development, are indeed well recapitulated during in vitro oogenesis in adult OSE cultures along with characteristic expression of stem/germ cell/oocyte markers. Further studies are required to assess the genetic integrity of in vitro derived oocytes before harnessing their clinical potential. Advance in our knowledge about germ cell differentiation from stem cells will enable researchers to design better in vitro strategies which in turn may have relevance to reproductive biology and regenerative medicine.

Proteomics of follicular fluid from women with polycystic ovary syndrome suggests molecular defects in follicular development

CONTEXT Polycystic ovary syndrome (PCOS), a major cause of anovulatory infertility, is characterized by arrested follicular growth. Altered protein levels in the follicular fluid surrounding the ovum may reflect the molecular defects of folliculogenesis in these women. OBJECTIVE To identify differentially regulated proteins in PCOS by comparing the follicular fluid protein repertoire of PCOS with healthy women. METHODS The follicular fluid samples were collected from PCOS and normo-ovulatory women undergoing in vitro fertilization. Follicular fluid proteins were subjected to digestion using trypsin, and resultant peptides were labeled with isobaric tags for relative and absolute quantification reagents and analyzed by liquid chromatography tandem mass spectrometry. Differential abundance of selected proteins was confirmed by ELISA. RESULTS A total of 770 proteins were identified, of which 186 showed differential abundance between controls and women with PCOS. Proteins involved in various processes of follicular development including amphiregulin; heparan sulfate proteoglycan 2; tumor necrosis factor, α-induced protein 6; plasminogen; and lymphatic vessel endothelial hyaluronan receptor 1 were found to be deregulated in PCOS. We also identified a number of new proteins from follicular fluid, whose function in the ovary is not yet clearly established. These include suprabasin; S100 calcium binding protein A7; and helicase with zinc finger 2, transcriptional coactivator. CONCLUSIONS Proteins indispensable for follicular growth were found to be differentially expressed in follicular fluid of women with PCOS, which may in part explain the aberrant folliculogenesis observed in these women.

Identification and validation of candidate biomarkers involved in human ovarian autoimmunity

Antibodies to multiple ovarian antigens have been proposed as markers of ovarian autoimmunity. The role of ovarian autoantibodies has been widely discussed in the pathophysiology of premature ovarian failure and unexplained infertility, but the autoantigens are yet to be identified. Three immunodominant ovarian autoantigens, α-actinin 4 (αACTN4), heat shock 70 protein 5 (HSPA5) and β-actin (ACTB), have been identified using anti-ovarian antibody-positive sera from women with idiopathic premature ovarian failure (n=50) and women undergoing IVF (n=695), using mass spectrometry. These autoantigens were subsequently validated using Western blot, immunohistochemistry and enzyme-linked immunosorbent assay. These autoantigens are localized to different components of the ovary such as the ooplasm of the oocyte, theca, granulosa, corpus luteum and zona pellucida. All the above antigens were found to be expressed in the ooplasm throughout follicular development. All the autoantigens are expressed specifically in the oocyte except αACTN4. The three autoantigens could contribute to the array of biomarkers to be used for developing specific and sensitive tests for diagnosis of women at risk of premature ovarian failure and IVF failure due to ovarian autoimmunity and could give an insight into the molecular mechanisms involved in the pathophysiology of these conditions.

Correlation of human sperm centrosomal proteins with fertility

OBJECTIVE: The centrosome is the microtubule organizing center (MTOC) paternally inherited by the zygote during fertilization. As the centrosome is located in the midpiece of the sperm tail, we presume that oligoasthenozoospermic sperm samples should also have abnormal concentrations of centrosomal proteins. This study therefore aims to determine if there is any correlation between sperm centrosomal proteins, centrin, α and γ-tubulin, in sperm samples from normozoospermic and oligoasthenozoospermic men. MATERIALS AND METHODS: Proteins were extracted from the normozoospermic and oligoasthenozoospermic sperm samples and analyzed by Western Blot and ELISA for centrin, α and γ-tubulin. RESULTS: The levels of centrin, α and γ-tubulin are markedly lower in oligoasthenozoospermic sperm samples as compared to the normozoospermic sperm samples. CONCLUSIONS: Lower centrosomal protein expression in sperm samples of oligoasthenozoospermic infertile males may be a possible cause for their reduced fertility status. Further studies on these proteins are warranted to design rational approaches for the diagnosis and treatment of male infertility.

Evaluating differentiation propensity of in-house derived human embryonic stem cell lines KIND-1 and KIND-2

Human embryonic stem (hES) cells possess the ability to self-renew indefinitely and provide a potential source of differentiated progeny representing all three embryonic germ layers. Although hES cell lines share the expression of typical pluripotency markers, limited data is available regarding their differentiation capabilities. We have earlier reported the in-house derivation of two hES cell lines, KIND-1 and KIND-2 on human feeders. Here, we describe a comparative study carried out on both these cell lines to better understand the differentiation potential of KIND-1 and KIND-2 by gene expression analysis of representative gene transcripts reflecting pluripotency and the three germ layers viz. ectoderm, mesoderm, and endoderm. Gene expression analysis and immunolocalization studies were undertaken on (a) 7- and 14-d old embryoid bodies (EBs) (b) spontaneously differentiated cells from EBs, (c) cells derived from EBs under the influence of various growth factor treatments and (d) KIND-1 and KIND-2 cells co-cultured on mouse embryonic visceral endoderm-like feeder (END-2). Despite both the cell lines being XX, derived, passaged, and cultured similarly, KIND-1 exhibits preferential differentiation towards endodermal lineage whereas KIND-2 spontaneously forms beating cardiomyocytes. Perhaps the occurrence of discrete epigenetic profile in both the cell lines predisposes them to encompass different developmental potential in vitro. Our data provide evidence for existence of distinct differentiation propensity among hES cell lines and emphasizes the need to derive more hES cell lines for future regenerative medicine.

Expression of Endometrial Protein Kinase A During Early Pregnancy in Bonnet Monkeys (Macaca radiata)

Embryo-induced signaling pathways are considered to be important for initiation and sustenance of pregnancy. However many of these pathways remain to be deciphered in primates. In the present study, differential display RT-PCR was used to identify genes or gene fragments that are differentially expressed in endometrium of bonnet monkeys (Macaca radiata) on Day 6 of pregnancy. Of several fragments found to be differentially expressed, a fragment of 567 base pair (named GG1) was characterized in detail. GG1 was highly represented in endometrium of pregnant animals compared with that of nonpregnant animals. Sequencing analysis revealed homology of this fragment to exons 7, 8, 9, and 10 and surprisingly to intron 6 of cAMP-dependent protein kinase A (PKA) regulatory type I alpha (tissue-specific extinguisher 1) (PRKAR1A). The increased expression of this fragment in gestational endometrium was confirmed by quantitative PCR studies. Two transcripts of 3.0 kilobase (kb) and 1.5 kb were detected in Northern blot probed with labeled GG1. Protein expressions of alpha regulatory (PRKAR1A) and alpha catalytic (PRKCA) subunits of PKA were also higher in gestational endometrium compared with that in nongestational endometrium. Further in vitro studies using human endometrial explants demonstrated regulation of PRKAR1A (or GG1) and prostaglandin-endoperoxide synthase 2 or cyclooxygenase 2 (PTGS2) by estradiol. This is the first study to date on the differential expression of PKA in primate endometrium during early pregnancy and its in vitro regulation by estradiol.

Progesterone requires heat shock protein 90 (HSP90) in human sperm to regulate motility and acrosome reaction.

PurposeThe aims of this paper were to study whether heat shock protein 90 (HSP90) is a regulator of sperm functions and to determine its association with oligoasthenozoospermia.MethodsThe levels of HSP90 in sperm lysates were measured by ELISA. Localization of HSP90 and its isoforms was evaluated by immunofluorescence. Sperm motility and kinetics were assessed by computer-assisted sperm analysis. Acrosome reaction was determined by lectin staining.ResultsThe levels of HSP90 were lower in oligoasthenozoospermic men and correlated positively with the number of motile spermatozoa. In capacitated human spermatozoa, HSP90α was mostly found in residual nuclear envelope, and the HSP90β isoform was higher in the flagella. Inhibition of HSP90 by geldanamycin or 17-AAG did not affect basal motility, but suppressed progesterone-mediated forward progressive motility, hyperactivation and acrosome reaction. Progesterone treatment dephosphorylated both HSP90α and HSP90β at Ser/Thr-Pro residues, but not Tyr residues.ConclusionHSP90 levels are downregulated in oligoasthenozoospermia, and its functional inhibition attenuates progesterone-mediated sperm motility and acrosome reaction.

Downregulation of genes related to immune and inflammatory response in IVF implantation failure cases under controlled ovarian stimulation

Implantation failure (IF) even after the good‐quality embryo transfer (ET) is main obstacle in in vitro fertilization (IVF). We aim to study the genomics of endometrial receptivity in IF patients under controlled ovarian stimulation (COS) during which ET is generally practised in IVF.