PACAP-mediated sperm–cumulus cell interaction promotes fertilization

The developing acrosome in spermatids contains pituitary adenylate cyclase-activating polypeptide (PACAP). However, the role of the acrosomal PACAP remains unclear because it has not been detected in mature spermatids and sperm. We reinvestigated whether the sperm acrosome contains PACAP. An antiserum produced against PACAP reacted to the anterior acrosome in epididymal sperm fixed under mild conditions, suggesting that PACAP acts on oocytes and/or cumulus cells at the site of fertilization. Immunolabeling and RT-PCR demonstrated the presence of PACAP type I receptor, a PACAP-specific receptor, in postovulatory cumulus cells. To investigate the role of PACAP in fertilization, we pretreated cumulus–oocyte complexes with the polypeptide. At a low concentration of sperm, the fertilization rate was significantly enhanced by PACAP in a dose-dependent manner. Sperm penetration through the oocyte investment, cumulus layer, and zona pellucida was also enhanced by PACAP. The enhancement was probably due to an enhancement in sperm motility and the zona-induced acrosome reaction, which were stimulated by a cumulus cell-releasing factor. Indeed, PACAP treatment increased the secretion of progesterone from the cumulus–oocyte complexes. These results strongly suggest that in response to PACAP, cumulus cells release a soluble factor that probably stimulates sperm motility and the acrosome reaction, thereby promoting fertilization.

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Sperm binding to ZP2-coated beads improve the efficiency of porcine in vitro fertilisation

Reproduction ◽

10.1530/rep-20-0123 ◽

2020 ◽

Vol 160 (5) ◽

pp. 725-735

Author(s):

Julieta Gabriela Hamze ◽

María Jiménez-Movilla ◽

Raquel Romar

Keyword(s):

Acrosome Reaction ◽

Cumulus Cell ◽

Cumulus Cells ◽

In Vitro Fertilisation ◽

Sperm Binding ◽

Fertilisation Rate ◽

Gamete Recognition ◽

Boar Spermatozoa

The role of specific zona pellucida (ZP) glycoproteins in gamete interaction has not yet been elucidated in many species. A recently developed 3D model based on magnetic sepharose beads (B) conjugated to recombinant ZP glycoproteins (BZP) and cumulus cells (CBZP) allows the study of isolated ZP proteins in gamete recognition studies. The objective of this work was to study the role of porcine ZP2, ZP3 and ZP4 proteins in sperm binding, cumulus cell adhesion and acrosome reaction triggering. ZP protein-bound beads were incubated with fresh ejaculated boar spermatozoa and isolated cumulus cells for 24 h. The number of sperm bound to the beads, the acrosomal shrouds (presence of acrosomal content) on the bead’s surface, and the acrosome integrity (by means of PNA-FITC lectin) in bound and unbound sperm were studied. Finally, in vitro matured porcine oocytes mixed with BZP2 were inseminated in vitro using fresh sperm and fertilisation results evaluated. Over 60% of beads had at least one sperm bound after 2 h of coincubation. ZP2-beads (BZP2) and cumulus-ZP2-bead complexes (CBZP2) reached the highest number of sperm per bead, whereas BZP3 and BZP4 models showed the highest number of unbound reacted sperm cells and acrosomal shrouds. Fertilisation efficiency and monospermy rate increased when oocytes were fertilised in the presence of BZP2. We, therefore, conclude that in pigs, it is mainly ZP2 that is involved in sperm-ZP binding whereas ZP3 and ZP4 induce acrosome reaction. Using magnetic sepharose ZP2-bound beads might be a valuable tool to improve the fertilisation rate in pigs.

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Roles of gene transcription and PKA subtype activation in maturation of murine oocytes

Reproduction ◽

10.1530/rep.0.1230799 ◽

2002 ◽

pp. 799-806 ◽

Cited By ~ 13

Author(s):

KF Rodriguez ◽

RM Petters ◽

AE Crosier ◽

CE Farin

Keyword(s):

Gene Transcription ◽

Cumulus Cell ◽

Cumulus Cells ◽

Type I ◽

Type Ii ◽

Germinal Vesicle Breakdown ◽

Series Of Experiments ◽

And Control ◽

Alpha Amanitin

The aims of this study were to examine the role of transcription and the coincident involvement of type I and type II protein kinase A (PKA) in the resumption of meiosis in murine cumulus-oocyte complexes (COCs) using the transcriptional inhibitors 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) and alpha-amanitin. The first series of experiments was designed to: (i) characterize the role of transcription in gonadotrophin-mediated and spontaneous maturation of murine oocytes; (ii) examine the roles of specific gonadotrophins (FSH versus hCG) and cumulus cells in transcriptionally mediated oocyte maturation; and (iii) determine the reversibility of the transcriptional arrest of meiosis. In the presence of FSH, transcriptional inhibitors arrested germinal vesicle breakdown (GVBD) (DRB: 2 +/- 2% and control: 76 +/- 2%; alpha-amanitin: 4 +/- 4% and control: 70 +/- 4%). Furthermore, cumulus cells were required for transcriptional inhibitors to arrest GVBD (DRB with cumulus cells: 0 +/- 15%; DRB without cumulus cells: 94 +/- 13%; alpha-amanitin with cumulus cells: 15 +/- 2%; alpha-amanitin without cumulus cells: 99 +/- 2%). Thus, in mice, FSH-mediated GVBD uses a transcriptional mechanism, which probably occurs within the cumulus cell compartment. In a second series of experiments, the role of transcription in mediating the resumption of meiosis after activation of either type I or type II PKA was examined. Activation of type I PKA in murine COCs resulted in an arrest of GVBD that was independent of a transcriptional event (with DRB: 7 +/- 9% GVBD; without DRB: 11 +/- 9% GVBD). In contrast, activation of type II PKA resulted in a resumption of meiosis, which required the occurrence of gene transcription (with DRB: 12 +/- 9% GVBD; without DRB: 80 +/- 9% GVBD). As FSH binding to cumulus cells activates the PKA second messenger system, our results indicate that, in cultured murine COCs, FSH binding to cumulus cells results in the activation of type II PKA, which, in turn, mediates a downstream transcriptional event required for the initiation of GVBD.

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Role of Angiotensin-(1–7) via MAS receptor in human sperm motility and acrosome reaction

Reproduction ◽

10.1530/rep-19-0274 ◽

2020 ◽

Vol 159 (3) ◽

pp. 241-249 ◽

Cited By ~ 9

Author(s):

Asier Valdivia ◽

Lorea Cortés ◽

Maider Beitia ◽

Lide Totorikaguena ◽

Naiara Agirregoitia ◽

...

Keyword(s):

Sperm Motility ◽

Acrosome Reaction ◽

Mrna Level ◽

Human Sperm ◽

Human Spermatozoa ◽

Dependent Manner ◽

Mas Receptor ◽

Sperm Mobility ◽

Specific Antagonist

Rennin-angiotensin system (RAS) has been involved in sperm function, even so, little is known about the implication of one of the RAS axis formed by Ang-(1–7) (angiotensin-(1–7)) and MAS receptor. Hence, in the present work, we focused on elucidating the function of the MAS receptor in human spermatozoa. We analyzed the expression and localization of MAS receptor in human spermatozoa and we observed if its activation is able to modulate the sperm motility of normal motility and/or asthenozoospermic patients, as well as, the acrosome reaction of the spermatozoa. MAS receptor is present in human mature spermatozoa, not only at the mRNA level but also at protein level. MAS is localized at the acrosome region, as well as, in the tail of spermatozoa. The sperm incubation with MAS agonist Ang-(1–7) activates at dose-dependent manner the PI3K/AKT pathway (P < 0.01 vs control) and improves the motility of asthenozoospermic patients (P < 0.01 vs control), which is blocked by the specific antagonist (A779) (P < 0.01), but it do not modulate the acrosome reaction. These findings suggest that the ACE2/Ang-(1–7)/Mas axis may be a useful biochemical tool for the treatment of male infertility related to sperm mobility.

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Role of Hypoxia-Mediated Autophagy in Tumor Cell Death and Survival

Cancers ◽

10.3390/cancers13030533 ◽

2021 ◽

Vol 13 (3) ◽

pp. 533

Author(s):

Rania F. Zaarour ◽

Bilal Azakir ◽

Edries Y. Hajam ◽

Husam Nawafleh ◽

Nagwa A. Zeinelabdin ◽

...

Keyword(s):

Cell Death ◽

Type I ◽

Dependent Manner ◽

Destruction Process ◽

Tumor Cell Death ◽

Complex Regulation ◽

Cancer Immunotherapies ◽

The Relationship ◽

Shed Light

Programmed cell death or type I apoptosis has been extensively studied and its contribution to the pathogenesis of disease is well established. However, autophagy functions together with apoptosis to determine the overall fate of the cell. The cross talk between this active self-destruction process and apoptosis is quite complex and contradictory as well, but it is unquestionably decisive for cell survival or cell death. Autophagy can promote tumor suppression but also tumor growth by inducing cancer-cell development and proliferation. In this review, we will discuss how autophagy reprograms tumor cells in the context of tumor hypoxic stress. We will illustrate how autophagy acts as both a suppressor and a driver of tumorigenesis through tuning survival in a context dependent manner. We also shed light on the relationship between autophagy and immune response in this complex regulation. A better understanding of the autophagy mechanisms and pathways will undoubtedly ameliorate the design of therapeutics aimed at targeting autophagy for future cancer immunotherapies.

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VCAM-1 is a CS1 peptide-inhibitable adhesion molecule expressed by lymph node high endothelium

Journal of Cell Science ◽

10.1242/jcs.106.1.109 ◽

1993 ◽

Vol 106 (1) ◽

pp. 109-119 ◽

Cited By ~ 1

Author(s):

M.J. May ◽

G. Entwistle ◽

M.J. Humphries ◽

A. Ager

Keyword(s):

Lymph Node ◽

Cell Interaction ◽

Tnf Alpha ◽

Dependent Manner ◽

Ifn Gamma ◽

Lymphocyte Adhesion ◽

Peripheral Lymph ◽

Endothelial Surface ◽

Dose Dependent

Previous studies have shown that unactivated lymphocytes bind to CS1 peptide and that the adhesion of these cells to high endothelium is inhibited by CS1 peptide. These results suggest that lymphocyte binding occurs via recognition of the CS1-containing splice variant of fibronectin expressed on the high endothelial surface. We have now extended these studies by determining the role of the CS1 receptor, alpha 4 beta 1 (VLA-4) and the alternative VLA-4 ligand, VCAM-1 in a rat model of lymphocyte-high endothelial cell interaction. Anti-VLA-4 antibody, HP2/1, blocked lymphocyte adhesion to resting and IFN-gamma (interferon-gamma) pretreated cultured high endothelial cells (HEC) in a dose-dependent manner with maximal inhibition of 60%. HP2/1 completely blocked the adhesion of rat lymphocytes to immobilized CS1 peptide and to a recombinant soluble (rs) form of human VCAM-1. Lymphocyte binding to rsVCAM-1 was also completely blocked by CS1 peptide. Anti-rat VCAM-1 monoclonal antibody 5F10 inhibited adhesion to untreated and IFN-gamma-treated HEC equally and its effect at 50% inhibition was slightly less than that of HP2/1. These findings suggest that a CS1 peptide-inhibitable ligand expressed by high endothelium is VCAM-1. The majority of cultured HEC expressed significant levels of VCAM-1 under basal conditions, as did HEV in peripheral lymph nodes. VCAM-1 expression by HEC was upregulated by cytokine pretreatment and the effects were ordered: IFN-gamma > TNF-alpha > IL-1 beta. The results described here demonstrate that rat peripheral lymph node HEC express VCAM-1, its expression is upregulated by cytokines, in particular IFN-gamma, and it supports the adhesion of unactivated lymphocytes. They also suggest that the VLA-4/VCAM-1 adhesion pathway may operate during the constitutive migration of lymphocytes into lymphoid organs. Although the mechanism of CS1 peptide inhibition was not determined, these results show that VCAM-1 is a CS1 peptide-inhibitable ligand and therefore CS1, on its own, cannot be used as a specific indicator of fibronectin activity.

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276 THE EFFECT OF CUMULUS CELLS DURING MATURATION ON THE RISE IN THE CONCENTRATION OF INTRACELLULAR Ca2+ ([Ca2+]i) OF PORCINE OOCYTES INDUCEDBY INOSITOL 1,4,5-TRISPHOSPHATE

Reproduction Fertility and Development ◽

10.1071/rdv17n2ab276 ◽

2005 ◽

Vol 17 (2) ◽

pp. 288

Author(s):

T. Amano ◽

T. Mori ◽

K. Matsumoto ◽

T. Watanabe ◽

A. Iritani

Keyword(s):

Cumulus Cells ◽

Immature Oocytes ◽

R Ratio ◽

Transient Rise ◽

Activation Rate ◽

Sperm Penetration ◽

Cytoplasmic Maturation ◽

Student’S T ◽

Rate Of Activation

Increase of inositol 1,4,5-triphosphate (IP3) in the cytoplasm of mammalian oocytes is said to be responsible for [Ca2+]i oscillation observed in the oocytes immediately after sperm penetration, and the [Ca2+]i oscillation is known to be essential for the development of embryos. On the other hand, cumulus cells have been reported to play an important role in cytoplasmic maturation of oocytes and affecting the embryonic development. To obtain more information about the role of cumulus cells in cytoplasmic maturation, the effects of cumulus cells during maturation on the rise in [Ca2+]i and on the rate of activation of porcine mature oocytes induced by IP3 injection were investigated. The immature porcine oocytes were divided into three groups: COCs (intact cumulus-oocyte complexes), DOs (oocytes denuded of their cumulus cells), Co-culture (DOs attached to separated cumulus cells). These groups of immature oocytes were cultured in NCSU23 46 h for maturation. To examine the function of cumulus cells, two groups of immature oocytes were also prepared: DOs + pyruvate (DOs put into NCSU23 with pyruvate) and COCs-glucose free (COCs put into NCSU23 without glucose). The mature oocytes from each group were loaded with Ca2+ indicator fluorescent dye Fura2-AM, and then were irradiated by 340 nm and 360 nm of ultraviolet immediately after the injection of IP3. The intensities of emission light caused by the irradiation of 340 nm and 360 nm ultraviolet were recorded as E340 and E360. Since coupling of Ca2+ and the dye intensifies E340, but does not change E360, the level of [Ca2+]i was shown as R (ratio = E340/E360) in this study. Activation rate was calculated by counting the number of the oocytes that formed pronuclei by injection of IP3. ANOVA and Student's t-test were used in this study. Transient rise in [Ca2+]i was observed in the mature oocytes from every group. The peak R of the rise in [Ca2+]i of the mature oocytes derived from COCs, Dos, and Co-culture and induced by IP3 were 7.2, 4.0, and 6.9, respectively. The R of DOs was significantly lower than those of the others (P < 0.05). Also, the activation rate of the mature oocytes from DOs was significantly lower than those from COCs and Co-culture (31, 66, and 66%). The mature oocytes from DOs + pyruvate showed the same level of peak R compared with those from COCs (7.4 and 6.3), but COCs-glucose free showed a slight but significantly lower peak R compared with the mature oocytes from COCs (6.0 and 7.4, P < 0.05). In conclusion, cumulus cells appeared to support the rise in [Ca2+]i of porcine oocytes induced by IP3 during maturation and the following activation. Moreover, a function of cumulus cells supposedly produces pyruvate by metabolizing glucose and provides it to oocytes during maturation for promoting the cytoplasmic maturation. A part of this study was supported by a Grant-in-Aid for the 21st Century COE Program of the Japan MEXT, and by a grant from the Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence of the JST.

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P–142 Comparison of the IVF outcome in the course of ICSI vs PICSI treatment continuation in exactly the same group of HBA abnormal patients

Human Reproduction ◽

10.1093/humrep/deab130.141 ◽

2021 ◽

Vol 36 (Supplement_1) ◽

Author(s):

M Rusin ◽

W Szecel ◽

M Jagiello ◽

J Liss ◽

K Lukaszuk

Keyword(s):

Binding Sites ◽

Poor Response ◽

Cumulus Cells ◽

Fertilization Rate ◽

Retrospective Case ◽

Plasmatic Membrane ◽

Registration Number ◽

Main Component ◽

Control Study

Abstract Study question Does the PICSI have a beneficial effect for men with abnormal HBA on the fertilization rate, blastocysts number and clinical pregnancies in the next attempt? Summary answer Patients with HBA <80% choosing to undergo PICSI after ICSI failure see an increase in blastocyst and pregnancy rates. What is known already Hyaluronic acid (HA) is a main component of cervical mucus and the extracellular matrix of cumulus cells. The formation of HA-binding sites in sperm cell membranes is one of the markers of sperm maturation indicating completion the spermatogenic process of remodelling the plasmatic membrane, cytoplasmic extrusion and nuclear maturity. Spermatozoa selected by the HA-binding technique (the physiologically selected intracytoplasmic sperm injection – PICSI) have a potentially reduced risk of chromosomal aneuploidy or DNA fragmentation. Recent evidence do not show significant benefits in using PICSI. However, it has not been analysed in the course of treatment continuation in the same patients. Study design, size, duration This was a retrospective case-control study. It included exactly the same 58 patients with abnormal HBA, who underwent IVF treatment with ICSI initially and later with PICSI, between January 2014 and October 2020 at INVICTA Fertility Centre, Poland. Median female partner age in PICSI group was 36,2±5,34, without PICSI 35,8 ±5,28. Participants/materials, setting, methods 275 cycles (130 ICSI and 145 PICSI) resulted in 793 and 897 MII respectively. Patients were also divided into two groups <80% and ≥80% depending on the obtained HBA score expressed as the percentage of sperm bound with hyaluronan. The analysis covered the fertilization rate (FR), TQ and total blastocyst rate on day 5 and clinical pregnancy rate. Patients with poor response to stimulation were excluded from the study. Main results and the role of chance FR in ICSI and PICSI groups was not significantly difference (57.00%±31.2 vs 59.87%±30.8) even when taking into account the division of patients according to the obtained HBA score. In the <80% group the FR was 57.04%±29.3 vs 59.54%±30.8 in ICSI vs PICSI group respectively. There were no significant differences when comparing the under HBA ≥80% subgroups for all analysed outcomes. Fertilization rate was 56.88% in the ICSI group vs 61.03% in the PICSI group. The percentage of blastocysts was 28.61% vs 34.45% and the percentage of TQ blastocysts on day 5 was 15.32% vs 16.81% with ICSI and PICSI respectively, in the group consisting of the same patients. In the HBA <80% group significant differences were observed in the percentage of obtained blastocysts 37.81% vs 47.61% by comparing the ICSI and PICSI approaches (p < 0.05). Also, percentage of TQ blastocyst on day 5 also was higher in patients with <80% HBA score after PICSI and was statistically significant (17.07% ICSI vs 23.92% PICSI, p < 0.05). We saw statistically significant (p < 0.01) increase in percentage of clinical pregnancies from 29.03% without PICSI to 69.44% in patient’s subsequent procedures involving PICSI. Limitations, reasons for caution More data is required to confirm that improved results of PICSI procedure are consistent and possible to reproduce in a larger group – and as a result could be included as part of the standard treatment process. Wider implications of the findings: The presented results show that in patients with normal HBA score, PICSI does not bring a measurable benefit and this may be important factor to consider in decision-making for couples seeking assistance. Trial registration number Not applicable

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Role of common cytokine receptor γ chain (γc)– and Jak3-dependent signaling in the proliferation and survival of murine mast cells

Blood ◽

10.1182/blood.v96.6.2172 ◽

2000 ◽

Vol 96 (6) ◽

pp. 2172-2180 ◽

Cited By ~ 92

Author(s):

Kotaro Suzuki ◽

Hiroshi Nakajima ◽

Norihiko Watanabe ◽

Shin-ichiro Kagami ◽

Akira Suto ◽

...

Keyword(s):

Bone Marrow ◽

Mast Cells ◽

Cytokine Receptor ◽

Type I ◽

Dependent Manner ◽

Type Ii ◽

Wild Type ◽

Peritoneal Mast Cells ◽

The Common

Abstract The regulatory roles of the common cytokine receptor γ chain (γc)– and Jak3-dependent signaling in the proliferation and survival of mast cells were determined using γc-deficient (γc−) and Jak3-deficient (Jak3−) mice. Although the mast cells in γc− and Jak3− mice were morphologically indistinguishable from those in wild-type mice, the number of peritoneal mast cells was decreased in γc− and Jak3− mice as compared with that in wild-type mice. Among γc-related cytokines, interleukin (IL)-4 and IL-9, but not IL-2, IL-7, or IL-15, enhanced the proliferation and survival of bone marrow–derived mast cells (BMMCs) from wild-type mice. However, the effects of IL-4 and IL-9 were absent in BMMCs from γc− and Jak3−mice. In addition, IL-4Rα, γc, and Jak3, but not IL-2Rβ or IL-7Rα, were expressed in BMMCs. In contrast, IL-13 did not significantly induce the proliferation and survival of BMMCs even from wild-type mice, and IL-13Rα1 was not expressed in BMMCs. Furthermore, IL-4 phosphorylated the 65-kd isoform of Stat6 in BMMCs from wild-type mice but not from γc− and Jak3− mice. These results indicate that γc- and Jak3-dependent signaling is essential for IL-4– and IL-9–induced proliferation and survival of murine mast cells, that the effects of IL-4 are mediated by type I IL-4R and that type II IL-4R is absent on mast cells, and that IL-4 phosphorylates the 65-kd isoform of Stat6 in mast cells in a γc- and Jak3-dependent manner.

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Binding of Brucella protein, Bp26, to select extracellular matrix molecules

BMC Molecular and Cell Biology ◽

10.1186/s12860-019-0239-7 ◽

2019 ◽

Vol 20 (1) ◽

Cited By ~ 4

Author(s):

Yasmin ElTahir ◽

Amna Al-Araimi ◽

Remya R. Nair ◽

Kaija J. Autio ◽

Hongmin Tu ◽

...

Keyword(s):

Extracellular Matrix ◽

Type I Collagen ◽

Host Cells ◽

Mouse Serum ◽

Enzyme Linked Immunosorbent Assay ◽

Target Cells ◽

Type I ◽

Dependent Manner ◽

Biolayer Interferometry

Abstract Background Brucella is a facultative intracellular pathogen responsible for zoonotic disease brucellosis. Little is known about the molecular basis of Brucella adherence to host cells. In the present study, the possible role of Bp26 protein as an adhesin was explored. The ability of Brucella protein Bp26 to bind to extracellular matrix (ECM) proteins was determined by enzyme-linked immunosorbent assay (ELISA) and biolayer interferometry (BLI). Results ELISA experiments showed that Bp26 bound in a dose-dependent manner to both immobilized type I collagen and vitronectin. Bp26 bound weakly to soluble fibronectin but did not bind to immobilized fibronectin. No binding to laminin was detected. Biolayer interferometry showed high binding affinity of Bp26 to immobilized type I collagen and no binding to fibronectin or laminin. Mapping of Bp26 antigenic epitopes by biotinylated overlapping peptides spanning the entire sequence of Bp26 using anti Bp26 mouse serum led to the identification of five linear epitopes. Collagen and vitronectin bound to peptides from several regions of Bp26, with many of the binding sites for the ligands overlapping. The strongest binding for anti-Bp26 mouse serum, collagen and vitronectin was to the peptides at the C-terminus of Bp26. Fibronectin did not bind to any of the peptides, although it bound to the whole Bp26 protein. Conclusions Our results highlight the possible role of Bp26 protein in the adhesion process of Brucella to host cells through ECM components. This study revealed that Bp26 binds to both immobilized and soluble type I collagen and vitronectin. It also binds to soluble but not immobilized fibronectin. However, Bp26 does not bind to laminin. These are novel findings that offer insight into understanding the interplay between Brucella and host target cells, which may aid in future identification of a new target for diagnosis and/or vaccine development and prevention of brucellosis.

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Hypoxia-inducible factor (HIF1alpha) inhibition modulates cumulus cell function and affects bovine oocyte maturation in vitro†

Biology of Reproduction ◽

10.1093/biolre/ioaa196 ◽

2020 ◽

Author(s):

Aslihan Turhan ◽

Miguel Tavares Pereira ◽

Gerhard Schuler ◽

Ulrich Bleul ◽

Mariusz P Kowalewski

Keyword(s):

Oocyte Maturation ◽

Cell Function ◽

Hypoxia Inducible Factor ◽

Cumulus Cell ◽

Cumulus Cells ◽

Negative Effects ◽

Protein Levels ◽

Maturation In Vitro

Abstract Various metabolic and hormonal factors expressed in cumulus cells are positively correlated with the in vitro maturation (IVM) of oocytes. However, the role of hypoxia sensing both during maturation of cumulus–oocyte complexes (COCs) as well as during the resumption of meiosis remains uncertain. HIF1alpha plays major roles in cellular responses to hypoxia, and here we investigated its role during bovine COC maturation by assessing the expression of related genes in cumulus cells. COCs were divided into the following groups: immature (control), in vitro matured (IVM/control), or matured in the presence of a blocker of HIF1alpha activity (echinomycin, IVM/E). We found an inhibition of cumulus cell expansion in IVM/E, compared with the IVM/control. Transcript levels of several factors (n = 13) were assessed in cumulus cells. Decreased expression of HAS2, TNFAIP6, TMSB4, TMSB10, GATM, GLUT1, CX43, COX2, PTGES, and STAR was found in IVM/E (P < 0.05). Additionally, decreased protein levels were detected for STAR, HAS2, and PCNA (P < 0.05), while activated-Caspase 3 remained unaffected in IVM/E. Progesterone output decreased in IVM/E. The application of PX-478, another blocker of HIF1alpha expression, yielded identical results. Negative effects of HIF1alpha suppression were further observed in the significantly decreased oocyte maturation and blastocyst rates from COCs matured with echinomycin (P < 0.05) or PX-478 (P < 0.05). These results support the importance of HIF1alpha for COC maturation and subsequent embryo development. HIF1alpha is a multidirectional factor controlling intercellular communication within COCs, steroidogenic activity, and oocyte development rates, and exerting effects on blastocyst rates.

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