|Vernadeth B. Alarcon
||School of Medicine, Institute for Biogenesis Research
||PhD (University of Toronto, Canada)
||(808) 692 1417
||(808) 692 1962
||651 Ilalo St., Biosciences Building, Room 163J/H, Honolulu, HI 96813
Preimplantation embryo, Cell lineage, Cell polarity, Developmental toxicants
Description of research:
Mammals, such as ourselves, are unique among other organisms in that our embryonic phase needs to implant into the mother's uterus and create the placenta to allow further development. To achieve such unique style of development, we have evolved to generate a special type of cells, called the trophectoderm, during the very early stages of embryo development (Figures 1 and 2). Trophectoderm is dedicated for implantation and placenta formation. In fact, the first and critical decision that embryonic cells must make after fertilization is whether they commit to become part of the future body or the trophectoderm, i.e., the precursor of placenta. This first decision needs to be controlled very carefully in a balanced manner because embryos cannot survive or develop further if one cell type (either "future body cells", called the inner cell mass, or "future placenta cells", the trophectoderm) is not generated sufficiently.
Our lab's research goal is to uncover the molecular mechanisms that control this early cell type decision-making, using mouse embryos as well as mouse and human cell lines. We have identified candidate genes, including cell polarity regulators (e.g., Alarcon 2010; Kono et al. 2014), and we are testing their roles in the embryo. We employ various experimental approaches, such as in vitro embryo culture, microinjection of the embryo, chimera production, embryo transfer into surrogate mother's reproductive tract, and cell and molecular biology techniques. Understanding the mechanisms of cell type decision-making in the early embryo has applications in the treatment of infertility, especially in ART (assisted reproductive technologies). Our findings have potential to serve as a basis for improving in vitro culture conditions of human embryos and for identifying healthy embryos for uterine transfer to produce successful pregnancies.
Figure 1: A preimplantation mouse embryo developing over time (left to right): 2-cell, 8-cell, early blastocyst, and late blastocyst. In the late blastocyst, cells have committed to the trophectoderm (future placenta) and inner cell mass (future body) lineages. Live development in vitro was recorded for three days, using time-lapse video microscopy.
Figure 2: Immunofluorescently stained blastocysts, showing expression of transcription factors essential for cell-type commitment. (A) OCT4 (green) protein is localized in inner cell mass. (B) CDX2 (yellow) protein is localized in trophectoderm. Nuclei are stained red with propidium iodide. Images were taken using confocal microscopy.
- Alarcon, V.B., Marikawa, Y. (2016) Statins inhibit blastocyst formation by preventing geranylgeranylation. Molecular Human Reproduction [Epub ahead of print]
- Kono, K., Tamashiro, D.A., Alarcon, V.B. (2014) Inhibition of RHO-ROCK signaling enhances ICM and suppresses TE characteristics through activation of Hippo signaling in the mouse blastocyst. Developmental Biology 394, 142-155.
- Laeno, A.M., Tamashiro, D.A., Alarcon, V.B. (2013) Rho-associated kinase activity is required for proper morphogenesis of the inner cell mass in the mouse blastocyst. Biology of Reproduction 89, 122.
- Hirate, Y., Hirahara, S., Inoue, K., Suzuki, A., Alarcon, V.B., Akimoto, K., Hirai, T., Hara, T., Adachi, M., Chida, K., Ohno, S., Marikawa, Y., Nakao, K., Shimono, A., Sasaki, H. (2013) Polarity-dependent distribution of angiomotin localizes Hippo signaling in preimplantation embryos. Current Biology 23, 1181-1194.
- Marikawa, Y., Alarcon, V.B. (2012) Creation of trophectoderm, the first epithelium, in mouse preimplantation development. Results and Problems in Cell Differentiation 55, 165-184. Book chapter.
- Alarcon, V.B. (2010) Cell polarity regulator PARD6B is essential for trophectoderm formation in the preimplantation mouse embryo. Biology of Reproduction 83, 347-358.
Commonly requested Alarcon's lab protocols:
- Immunofluorescent staining of preimplantation embryos (under construction)
- Marikawa, Y., Alarcon, V.B. (2009) Establishment of trophectoderm and inner cell mass lineages in the mouse embryo. Molecular Reproduction and Development 76, 1019-1032.
- Marikawa, Y., Tamashiro, D.A., Fujita, T.C., Alarcon, V.B. (2009) Aggregated P19 mouse embryonal carcinoma cells as a simple in vitro model to study the molecular regulations of mesoderm formation and axial elongation morphogenesis. Genesis 47, 93-106.
- Alarcon, V.B., Marikawa, Y. (2008) Spatial alignment of the mouse blastocyst axis across the first cleavage plane is caused by mechanical constraint rather than developmental bias among blastomeres. Molecular Reproduction and Development 75, 1143-1153.
- Tamashiro, D.A., Alarcon, V.B., Marikawa, Y. (2008) Ectopic expression of mouse Sry interferes with Wnt/beta-catenin signaling in mouse embryonal carcinoma cell lines. Biochimica Biophysica Acta 1780, 1395-1402.
- Fogelgren, B., Kuroyama, M.C., McBratney-Owen, B., Spence, A.A., Malahn, L.E., Anawati, M.K., Cabatbat, C., Alarcon, V.B., Marikawa, Y., Lozanoff, S. (2008) Misexpression of Six2 is associated with heritable frontonasal dysplasia and renal hypoplasia in 3H1 Br mice. Developmental Dynamics 237, 1767-1779.
- Yamazaki, Y., Fujita, T.C., Low, E.W., Alarcon, V.B., Yanagimachi, R., Marikawa, Y. (2006) Gradual DNA demethylation of the Oct4 promoter in cloned mouse embryos. Molecular Reproduction and Development 73, 180-188.
- Hiiragi, T., Alarcon, V.B., Fujimori, T., Louvet-Vallee, S., Maleszewski, M., Marikawa, Y., Maro, B., Solter, D. (2006) Where do we stand now? Mouse early embryo patterning meeting in Freiburg, Germany (2005). International Journal of Developmental Biology 50, 581-588.
- Alarcon, V.B., Marikawa, Y. (2005) Unbiased contribution of the first two blastomeres to mouse blastocyst development. Molecular Reproduction and Development 72, 354-361.
- Marikawa, Y., Fujita, T.C., Alarcon, V.B. (2005) Heterogeneous DNA methylation status of the regulatory element of the mouse Oct4 gene in adult somatic cell population. Cloning and Stem Cells 7, 8-16.
- Alarcon, V.B., Marikawa, Y. (2004) Molecular study of mouse peri-implantation development using the in vitro culture of aggregated inner cell mass. Molecular Reproduction and Development 67, 83-90.
- Marikawa, Y., Fujita, T.C., Alarcon, V.B. (2004) An enhancer-trap LacZ transgene reveals a distinct expression pattern of Kinesin family 26B in mouse embryos. Development Genes and Evolution 214, 64-71.
- Alarcon, V.B., Marikawa, Y. (2003) Deviation of the blastocyst axis from the first cleavage plane does not affect the quality of mouse postimplantation development. Biology of Reproduction 69, 1208-1212.
- Alarcon, V.B., Elinson, R.P. (2001) RNA anchoring in the vegetal cortex of the Xenopus oocyte. Journal of Cell Science 114, 1731-1741.
- Alarcon, V.B., Filosa, M.F., Youson, J.H. (1997) Cytokeratins in the liver of the sea lamprey (Petromyzon marinus) before and after metamorphosis. Cell and Tissue Research 287, 365-374.
- Hudson, J.W., Alarcon, V.B., Elinson, R.P. (1996) Identification of new localized RNAs in the Xenopus oocyte by differential display PCR. Developmental Genetics 19, 190-198.
- Alarcon, V.B., Filosa, M.F., Youson, J.H. (1994) Keratin polypeptides in the epidermis of the larval (ammocoete) sea lamprey, Petromyzon marinus L., show a cell type-specific immunolocalization. Canadian Journal of Zoology 72, 190-194.