Cytochemical establishment of acid phosphatase in the bovine endometrium and trophoblast during implantation

The presence of blastocyst within the uteri facilitates lumenal epithelium transformation for implantation via upregulating lysosome proteostasis activity

ABBREVIATIONS

ACTB: actin beta; AREG: amphiregulin; ATP6V0A4: ATPase, H+ transporting, lysosomal V0 subunit A4; Baf A1: bafilomycin A1; BSA: bovine serum albumin; CLDN1: claudin 1; CTSB: cathepsin B; DEGs: differentially expressed genes; E2: 17β-estradiol; ESR: estrogen receptor; GATA2: GATA binding protein 2; GLA: galactosidase, alpha; GO: gene ontology; HBEGF: heparin-binding EGF-like growth factor; IGF1R: insulin-like growth factor 1 receptor; Ihh: Indian hedgehog; ISH: in situ hybridization; LAMP1: lysosomal-associated membrane protein 1; LCM: laser capture microdissection; Le: lumenal epithelium; LGMN: legumain; LIF: leukemia inhibitory factor; LIFR: LIF receptor alpha; MSX1: msh homeobox 1; MUC1: mucin 1, transmembrane; P4: progesterone; PBS: phosphate-buffered saline; PCA: principal component analysis; PPT1: palmitoyl-protein thioesterase 1; PGR: progesterone receptor; PSP: pseudopregnancy; PTGS2/COX2: prostaglandin-endoperoxide synthase 2; qPCR: quantitative real-time polymerase chain reaction; SP: pregnancy; TFEB: transcription factor EB.

The constructive and destructive impact of autophagy on both genders' reproducibility, a comprehensive review

Reproduction is characterized by a series of massive renovations at molecular, cellular, and tissue levels. Recent studies have strongly tended to reveal the involvement of basic molecular pathways such as autophagy, a highly conserved eukaryotic cellular recycling, during reproductive processes. This review comprehensively describes the current knowledge, updated to September 2022, of autophagy contribution during reproductive processes in males including spermatogenesis, sperm motility and viability, and male sex hormones and females including germ cells and oocytes viability, ovulation, implantation, fertilization, and female sex hormones. Furthermore, the consequences of disruption in autophagic flux on the reproductive disorders including oligospermia, azoospermia, asthenozoospermia, teratozoospermia, globozoospermia, premature ovarian insufficiency, polycystic ovarian syndrome, endometriosis, and other disorders related to infertility are discussed as well.Abbreviations: AKT/protein kinase B: AKT serine/threonine kinase; AMPK: AMP-activated protein kinase; ATG: autophagy related; E2: estrogen; EDs: endocrine disruptors; ER: endoplasmic reticulum; FSH: follicle stimulating hormone; FOX: forkhead box; GCs: granulosa cells; HIF: hypoxia inducible factor; IVF: in vitro fertilization; IVM: in vitro maturation; LCs: Leydig cells; LDs: lipid droplets; LH: luteinizing hormone; LRWD1: leucine rich repeats and WD repeat domain containing 1; MAP1LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MTOR: mechanistic target of rapamycin kinase; NFKB/NF-kB: nuclear factor kappa B; P4: progesterone; PCOS: polycystic ovarian syndrome; PDLIM1: PDZ and LIM domain 1; PI3K: phosphoinositide 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns3K: class III phosphatidylinositol 3-kinase; POI: premature ovarian insufficiency; ROS: reactive oxygen species; SCs: Sertoli cells; SQSTM1/p62: sequestosome 1; TSGA10: testis specific 10; TST: testosterone; VCP: vasolin containing protein.

Acidification of uterine epithelium during embryo implantation in mice

Uterine luminal epithelium (LE) is essential for establishing uterine receptivity. Previous microarray analysis revealed upregulation of Atp6v0d2 in gestation day 4.5 (D4.5) LE in mice. Realtime PCR showed upregulation of uterine Atp6v0d2 starting right before embryo attachment ∼D4.0. In situ hybridization demonstrated specific uterine localization of Atp6v0d2 in LE upon embryo implantation. Atp6v0d2 encodes one subunit for vacuolar-type H+-ATPase (V-ATPase), which regulates acidity of intracellular organelles and extracellular environment. LysoSensor Green DND-189 detected acidic signals in LE and glandular epithelium upon embryo implantation, correlating with Atp6v0d2 upregulation in early pregnant uterus. Atp6v0d2-/- females had significantly reduced implantation rate and marginally reduced delivery rate from first mating only, but comparable number of implantation sites and litter size compared to control and comparable fertility to control from subsequent matings, suggesting a nonessential role of Atp6v0d2 subunit in embryo implantation. Successful implantation in both control and Atp6v0d2-/- females was associated with uterine epithelial acidification. No significant compensatory upregulation of Atp6v0d1 mRNA was detected in D4.5 Atp6v0d2-/- uteri. To determine the role of V-ATPase instead of a single subunit in embryo implantation, a specific V-ATPase inhibitor bafilomycin A1 (2.5 μg/kg) was injected via uterine fat pad on D3 18:00 h. This treatment resulted in reduced uterine epithelial acidification, delayed implantation, and reduced number of implantation sites. It also suppressed oil-induced artificial decidualization. These data demonstrate uterine epithelial acidification as a novel phenomenon during embryo implantation and V-ATPase is involved in uterine epithelial acidification and uterine preparation for embryo implantation.

Survival by self-destruction: a role for autophagy in the placenta?

Autophagy is a burgeoning area of research from yeast to humans. Although previously described as a death pathway, autophagy is now considered an important survival phenomenon in response to environmental stressors to which most organs are exposed. Despite an ever expanding literature in non-placental cells, studies of autophagy in the placenta are lagging. We review the regulation of autophagy, summarize available placental studies of autophagy, and highlight potential areas for future research. We believe that such studies will yield novel insights into how placentas protect the survival of the species by "self-eating".

The bovine placenta; a source and target of steroid hormones: observations during the second half of gestation

Apart from estrone-3-sulfate (E1S) the bovine placenta produces progesterone (P4), though the corpus luteum is the major source of P4 responsible for maintaining pregnancy. So far the biological function of placental steroids in cattle is largely unknown. However, since the local availability of free estrone (E1) in the placenta seems to be controlled by sulfatase and sulfotranferase, the hypothesis was developed that placental estrogens and P4 might act as local regulatory factors. To test for such a function placentomes from 150, 220, 240, 270 days (D) pregnant and parturient cows were screened immunohistochemically for progesterone and estrogen receptors (PR, ER). PR were found at all stages in the caruncle in stromal cells and capillary pericytes but only at parturition in arterial walls. Percentage of PR-positive caruncular stromal cells (CSC) increased (P<0.05) from 51.8+/-2.6% at D150 to 58.9+/-1.8% at parturition. ER were detected in CSC, caruncular epithelial (CE) cells and in caruncular capillary pericytes. Mean percentage of ER-positive CSC decreased from 39.0+/-5.9% in pregnant cows to 17.5+/-8.3% at parturition (P<0.05). In CE all cells exhibited positive signals with the exception of those immediately surrounding large primary chorionic villi. Proliferation was assessed immunohistochemically by determining the percentage of Ki67-antigen positive cells. Highest values (P<0.001) were obtained for CE (58.0-68.3%), followed by the trophoblast (23.3-25.4%), CSC (10.6-45.3%) and the stroma of the chorionic villi (2.9-10.5%). A transient depression of proliferation in CSC between D150-270 (P<0.05) paralleled local estrogen tissue concentrations. The results suggest that placental estrogens and P4 are important factors controlling caruncular growth, differentiation and function.

An electron microscopic study of implantation in the cow

The paper describes the changes occurring in the uterine and chorionic epithelia of the cow between days 18 and 28 of gestation, before and during implantation. The irregular uterine epithelium of the non-pregnant cow was simplified to a tall columnar epithelium before attachment began. Areas of attachment were first observed at day 20 in the region of the embryo. Such sites were characterized by the presence of pale uterine cells containing up to 8 nuclei ("giant cells") which accounted for nearly 50% of the epithelial area by day 24. Fetal binucleate cells were found in contact with, and partly across, the microvillar junction at all stages examined, and the presence of granules characteristic of binucleate cells within the giant cells suggested that the fetal cells contributed to their formation. Many uterine epithelial cells underwent degenerative changes between 22 and 28 days, and residues equivalent to their pyknotic remnants were found at the microvillar junction and within the mononucleate chorion cells. By day 28 some of the giant cells appeared to be degenerating, and areas of low cuboidal epithelium were present. This epithelium resembled the type found in the mature placenta. There was evidence that binucleate cell migration continued at this time. Nevertheless, the definitive membrane in the mature bovine placenta is epitheliochorial.