Calcium Signaling During Meiotic Cell Cycle Regulation and Apoptosis in Mammalian Oocytes

Abstract

Calcium (Ca ) is one of the major signal molecules that regulate various aspects of cell functions including cell cycle progression, arrest, and apoptosis in wide variety of cells. This review summarizes current knowledge on the differential roles of Ca in meiotic cell cycle resumption, arrest, and apoptosis in mammalian oocytes. Release of Ca from internal stores and/or Ca influx from extracellular medium causes moderate increase of intracellular Ca ([Ca ]i) level and reactive oxygen species (ROS). Increase of Ca as well as ROS levels under physiological range trigger maturation promoting factor (MPF) destabilization, thereby meiotic resumption from diplotene as well as metaphase-II (M-II) arrest in oocytes. A sustained increase of [Ca ]i level beyond physiological range induces generation of ROS sufficient enough to cause oxidative stress (OS) in aging oocytes. The increased [Ca ]i triggers Fas ligand-mediated oocyte apoptosis. Further, OS triggers mitochondria-mediated oocyte apoptosis in several mammalian species. Thus, Ca exerts differential roles on oocyte physiology depending upon its intracellular concentration. A moderate increase of [Ca ]i as well as ROS mediate spontaneous resumption of meiosis from diplotene as well as M-II arrest, while their high levels cause meiotic cell cycle arrest and apoptosis by operating both mitochondria- as well as Fas ligand-mediated apoptotic pathways. Indeed, Ca regulates cellular physiology by modulating meiotic cell cycle and apoptosis in mammalian oocytes. J. Cell. Physiol. 232: 976-981, 2017. © 2016 Wiley Periodicals, Inc.

Role of Mitogen Activated Protein Kinase and Maturation Promoting Factor During the Achievement of Meiotic Competency in Mammalian Oocytes

“…Once the meiosis resume from diplotene arrest, it passes through M‐I and reaches to M‐II stage just prior to or at the time of ovulation in several mammalian species [Tripathi et al, ; Tiwari et al, ,,]. The MAPK3/1 activity is maximum during M‐I as well as M‐II arrest in porcine as well as bovine oocytes [Wehrend and Meinecke, ].…”

“…On the other hand, decreased Thr161 phosphorylated Cdk1 as well as cyclin B1 levels and increased Thr14/Tyr15 phosphorylated Cdk1 level destabilize MPF [Oh et al, ; Premkumar and Chaube, , ; Prasad et al, ,, ,]. The destabilized MPF triggers meiotic resumption from diplotene arrest in most of the mammalian species [Pandey et al, ; Tripathi et al, ; Tiwari et al, , ,; Gupta et al, ]. This event is mediated by chromatin condensation and spindle formation in rat and mouse oocytes [Josefsberg et al, ; Kong et al, ].…”

Journey of oocyte from metaphase‐I to metaphase‐II stage in mammals

“…Once meiosis resumes from diplotene arrest, oocyte reaches to M‐I stage both in vivo as well as in vitro culture conditions. However, in few mammalian species, oocyte does not progress beyond metaphase‐I (M‐I) stage under in vitro culture conditions (Pandey et al, ; Tiwari et al, ; Tiwari, Prasad, Shrivastav, & Chaube, ; Tripathi et al, ). The human chorionic gonadotrophin surge triggers meiotic cell cycle progression from M‐I stage and oocyte progresses to achieve physiological arrest at metaphase‐II (M‐II) stage and extrude first polar body (PB‐I) (Gupta, Tiwari, Prasad, & Chaube, ; Kubiak, Ciemerych, Hupalowska, Sikora‐Polaczek, & Polanski, ; Tiwari et al, ; Tripathi et al, ).…”

“…The cytoplasm of M‐II arrested oocytes devoid of GV and nucleolus and possessing PB‐I until fertilization or parthenogenetic activation. Fertilizing spermatozoa trigger meiotic exit from M‐II arrest through calcium (Ca ++ ) mediated pathway (Premkumar & Chaube, , ; Tiwari, Prasad, et al, ). In several mammalian species, oocytes do not wait for fertilizing spermatozoa and quickly undergo spontaneous exit from M‐II arrest, so called spontaneous egg activation (SEA) (Tiwari, Prasad, et al, ).…”

Fabrication of large-pore mesoporous Ca-Si-based bioceramics for bone regeneration

“…If the concentration of calcium is raised at this time, the cells can then continue to conduct DNA synthesis, that is, to promote cell proliferation. 17,18 Moreover, calcium is a common allosteric growth factor that regulates cell differentiation by the cytoplasm, organelles, and enzymes in the nucleus. 19,20 Although elevated calcium ions inhibit the early osteogenic differentiation of cells, they can promote the maturation and mineralization of cells at the later stage, which is beneficial to the formation of bone.…”