Mammalian fertilization begins with the fusion of two specialized gametes, followed by major epigenetic remodeling leading to the formation of a totipotent embryo. During the development of the pre-implantation embryo, precise reprogramming progress is a prerequisite for avoiding developmental defects or embryonic lethality, but the underlying molecular mechanisms remain elusive. For the past few years, unprecedented breakthroughs have been made in mapping the regulatory network of dynamic epigenomes during mammalian early embryo development, taking advantage of multiple advances and innovations in low-input genome-wide chromatin analysis technologies. The aim of this review is to highlight the most recent progress in understanding the mechanisms of epigenetic remodeling during early embryogenesis in mammals, including DNA methylation, histone modifications, chromatin accessibility and 3D chromatin organization.
Animals ; Chromatin Assembly and Disassembly ; DNA Methylation ; DNA Transposable Elements ; Embryo, Mammalian ; Embryonic Development/genetics* ; Epigenesis, Genetic ; Epigenome ; Female ; Fertilization/physiology* ; Gene Expression Regulation, Developmental ; Histone Code ; Histones/metabolism* ; Male ; Mice ; Oocytes/metabolism* ; Spermatozoa/metabolism*

Animals ; Antigens, Surface/genetics* ; Cell Communication/genetics* ; Copulation/physiology* ; Fallopian Tubes/metabolism* ; Female ; Fertilization/genetics* ; GPI-Linked Proteins/genetics* ; Gene Expression Regulation ; Genes, Reporter ; Green Fluorescent Proteins/metabolism* ; Litter Size ; Luminescent Proteins/metabolism* ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Mitochondria/metabolism* ; Reproduction/genetics* ; Signal Transduction ; Sperm Count ; Sperm Motility/genetics* ; Spermatozoa/metabolism* ; Uterus/metabolism*

Endometrial receptivity has become the main cause of fertilization and pregnancy outcomes in infertile patients,bringing large psychological damage and economic loss to the patients and their family. In recent years,the role of non-coding RNA has increasingly been recognized. The relationship between non-coding RNA and endometrial receptivity is reviewed in this article.
Embryo Implantation ; Endometrium ; physiology ; Female ; Fertilization in Vitro ; Humans ; Pregnancy ; Pregnancy Outcome ; RNA, Untranslated ; genetics

Objective: To elucidate the possible role of human lysozyme-like protein 4 (LYZL4) in fertilization and characterize its enzymatic properties. METHODS: The localization of LYZL4 in human spermatozoa was investigated by immunofluorescence staining, the sources of LYZL4 on the sperm surface examined by RT-PCR, and the role of LYZL4 in fertilization assessed by the zona-free hamster egg penetration test. The recombinant plasmid pPIC9K-LYZL4 was constructed and its expression induced with methanol after transformed into competent Pichia pastoris GS115. The recombinant LYZL4 protein (rLYZL4) was purified from the fermentation supernatant and subsequently identified by Western blot. The hyaluronan binding ability of rLYZL4 was determined by ELISA and the muramidase activity, hyaluronidase activity, and free radical scavenging ability examined by spectrophotometric methods. RESULTS: Immunodetection with a specific antiserum localized LYZL4 on the acrosomal membrane of mature spermatozoa, which was exclusively secreted from the testis and epididymis as shown by RT-PCR. Immunoneutralization of LYZL4 significantly decreased the number of human spermatozoa bound to zona-free hamster eggs in a dose-dependent manner in vitro. The recombinant protein was expressed successfully by the P. pastoris strain GS115. Purified rLYZL4 exhibited a potent hyaluronan binding ability and a strong free radical scavenging ability but no muramidase or hyaluronidase activity. CONCLUSIONS LYZL4 secreted from the testis and epididymis is localized on the acrosomal membrane of mature spermatozoa and plays a role in sperm-egg binding as well as in binding hyaluronan and scavenging free radicals, which suggests that it might be a multi-functional molecule contributive to sperm protection and sperm-egg binding.
Acrosome ; enzymology ; Animals ; Blotting, Western ; Cricetinae ; Enzyme-Linked Immunosorbent Assay ; Epididymis ; Female ; Fertilization ; physiology ; Free Radical Scavengers ; metabolism ; Humans ; Hyaluronic Acid ; metabolism ; Male ; Muramidase ; analysis ; physiology ; Pichia ; Plasmids ; metabolism ; Recombinant Proteins ; analysis ; metabolism ; Sperm-Ovum Interactions ; physiology ; Spermatozoa ; enzymology ; Testis

Angiotensin-converting enzyme functions in the male reproductive system, but the extent of its function in reproduction is not fully understood. The primary objective of this work was to investigate the relationship between the testicular isoform of angiotensin-converting enzyme present in human spermatozoa and semen parameters, human embryo quality, and assisted reproduction success. A total of 81 semen samples and 635 embryos from couples undergoing oocyte donation cycles at the IVI Bilbao Clinic were analyzed. Semen parameters, embryos quality, and blastocyst development were examined according to the World Health Organization standards and the Spanish Association of Reproduction Biology Studies criteria. The percentage of testicular angiotensin-converting enzyme-positive spermatozoa and the number of molecules per spermatozoon were analyzed by flow cytometry. Both parameters were inversely correlated with human sperm motility. Higher percentages of testicular angiotensin-converting enzyme-positive spermatozoa together with fewer enzyme molecules per spermatozoon were positively correlated with better embryo quality and development. Our results suggest that embryos with a higher implantation potential come from semen samples with higher percentages of testicular angiotensin-converting enzyme-positive cells and fewer enzyme molecules per spermatozoon. Based on these findings, we propose that testicular angiotensin-converting enzyme could be used to aid embryologists in selecting better semen samples for obtaining high-quality blastocysts during in vitro fertilization procedures.
Adult ; Embryo Implantation/physiology* ; Embryo Transfer ; Embryonic Development/physiology* ; Fertility/physiology* ; Fertilization in Vitro ; Humans ; Male ; Middle Aged ; Peptidyl-Dipeptidase A/metabolism* ; Sperm Motility/physiology* ; Spermatozoa/enzymology* ; Testis/enzymology*

OBJECTIVE: Hyperstimulation methods are broadly used for in vitro fertilization (IVF) in patients with infertility; however, the side effects associated with these therapies, such as ovarian hyperstimulation syndrome (OHSS), have not been well studied. N-glycoproteomes are subproteomes used for the remote sensing of ovarian stimulation in follicular growth. Glycoproteomic variation in human follicular fluid (hFF) has not been evaluated. In this study, we aimed to identify and quantify the glycoproteomes and N-glycoproteins (N-GPs) in natural and stimulated hFF using label-free nano-liquid chromatography/electrospray ionization-quad time-of-flight mass spectrometry. METHODS: For profiling of the total proteome and glycoproteome, pooled protein samples from natural and stimulated hFF samples were selectively isolated using hydrazide chemistry to obtain the total proteomes and glycoproteomes. N-GPs were validated by the consensus sequence N-X-S/T (92.2% specificity for the N-glycomotif at p<0.05). All data were compared between natural versus hyperstimulated hFF samples. RESULTS: We detected 41 and 44 N-GPs in the natural and stimulated hFF samples, respectively. Importantly, we identified 11 N-GPs with greater than two-fold upregulation in stimulated hFF samples compared to natural hFF samples. We also validated the novel N-GPs thyroxine-binding globulin, vitamin D-binding protein, and complement proteins C3 and C9. CONCLUSION: We identified and classified N-GPs in hFF to improve our understanding of follicular physiology in patients requiring assisted reproduction. Our results provided important insights into the prevention of hyperstimulation side effects, such as OHSS.
Chemistry ; Complement System Proteins ; Consensus Sequence ; Female ; Fertilization in Vitro* ; Follicular Fluid* ; Humans* ; In Vitro Techniques* ; Infertility ; Mass Spectrometry ; Ovarian Hyperstimulation Syndrome ; Ovulation Induction ; Physiology ; Proteome ; Proteomics ; Reproduction ; Sensitivity and Specificity ; Thyroxine-Binding Globulin ; Up-Regulation ; Vitamin D-Binding Protein

OBJECTIVETo investigate the influence of the rate of morphologically normal sperm (MNS) on the clinical outcomes of conventional in vitro fertilization (IVF) in patients with one retrieved oocyte.

METHODSFrom January 2013 to January 2015, a total of 256 couples with one retrieved oocyte underwent conventional IVF in our center. According to the rate of MNS, the patients were divided into two groups: MNS < 4% (134 cycles) and MNS ≥ 4% (122 cycles). We compared the rates of no transferrable embryo cycles, fertilization, cleavage, normal fertilization, abnormal fertilization, high-quality embryo and transferrable embryo between the two groups. A total of 75 fresh embryo transfer cycles were performed, 43 in the MNS < 4% group and the other 32 in the MNS ≥ 4% group. We also compared the rates of implantation, clinical pregnancy and abortion between the two groups.

RESULTSThere were no statistically significant differences between the two groups in the rates of no transferrable embryo cycles, fertilization, cleavage, normal fertilization, abnormal fertilization, high-quality embryo and transferrable embryo (P > 0.05). The rates of implantation, clinical pregnancy and abortion exhibited no remarkable differences either in the fresh embryo transfer cycles between the two groups (P > 0.05).

CONCLUSIONThe rate of MNS does not affect the clinical outcomes of conventional IVF in patients with one retrieved oocyte.

Abortion, Spontaneous ; Cleavage Stage, Ovum ; Embryo Implantation ; Female ; Fertilization ; Fertilization in Vitro ; methods ; statistics & numerical data ; Humans ; Male ; Oocyte Retrieval ; Pregnancy ; Pregnancy Rate ; Single Embryo Transfer ; statistics & numerical data ; Sperm Count ; Spermatozoa ; physiology

OBJECTIVETo evaluate the impact of sperm midpiece morphology observed under high-power microscope on embryo development following intracytoplasmic morphologically selected sperm injection.

METHODSMorphologically normal sperms from 57 patients undergoing intracytoplasmic sperm injection (ICSI) for male-factor infertility were selected microscopically (magnification of ×200 or 400) and subjected to motile sperm organellar morphology examination (MSOME) at high magnification of ×6000. According to the morphology of sperm medpiece, the sperms were divided into 3 groups, namely group A with a/b of 1-1.2, group B with a/b≥1.5, and group C with irregular morphology. The sperms in the 3 groups were intracytoplasmically injected in oocytes and the outcomes of the embryos were compared.

RESULTSGroups A, B, and C showed significant differences in the rate of ET-D3 top quality embryo (79.7% vs 55.6 % vs 33.3%) and implantation rate (43.2% vs 11.1% vs 0%), but not in the fertilization rate (73.3% vs 80.4% vs 63.5%), blastocyst formation rate (23.2% vs 22.2% vs 9.09%), cryopreservation rate (29.2% vs 25.0 % vs 13.0%), or D3 top quality embryo rate (35.3% vs 37.8% vs 18.8%).

CONCLUSIONSIn ICSI cycle, selecting morphologically normal sperms for intracytoplasic injection can increase the normal fertilization rate and top quality embryo rate on the transfer day and improve the implantation rate of the embryo.

Cryopreservation ; Embryo Implantation ; Embryonic Development ; Female ; Fertilization ; Humans ; Infertility, Male ; Male ; Oocytes ; Semen Analysis ; Sperm Injections, Intracytoplasmic ; Sperm Midpiece ; physiology

OBJECTIVETo investigate the feasibility and clinical application value of selecting viable spermatozoa by noncontact diode laser.

METHODSWe obtained immotile spermatozoa from 2 infertile men with obstructive azoospermia or severe asthenospermia and selected viable spermatozoa using a single laser shot at the sperm tail. Those that responded to the laser shot by a curling reaction of the tail were regarded as presumably viable and used for intracytoplasmic sperm injection (ICSI).

RESULTSThe mean fertilization rate was 88.89% after ICSI with the laser-selected viable spermatozoa. Both of the embryo transfers resulted in a single pregnancy.

CONCLUSIONNoncontact diode laser is a useful alternative for the assessment of sperm viability, which may help to achieve successful pregnancy.

Embryo Transfer ; Female ; Fertilization ; Humans ; Infertility, Male ; therapy ; Male ; Pregnancy ; Pregnancy Outcome ; Sperm Injections, Intracytoplasmic ; Sperm Motility ; Sperm Tail ; physiology

BACKGROUNDGenerally, intracytoplasmic sperm injection (ICSI) may be the preferable method to treat partial globozoospermia, but whether there exist some correlations between ICSI fertilization rate and the proportion of round-headed sperm or morphologically normal sperm remains open. This study was to explore the correlation between ICSI fertilization rate and the sperm morphology in patients with partial globozoospermia.

METHODSThirty-four patients diagnosed with partial globozoospermia accepted the following assisted fertilization treatments - 2 cases accepted in-vitro fertilization (IVF) alone, 26 cases accepted ICSI alone, and 6 accepted split IVF/ICSI. Detailed morphological characteristics were described using Diff-Quik rapid staining. Sixty cases accepting IVF or ICSI treatment in our reproductive center were considered as the control group after being matched by relevant criteria. Fertilization rate, embryo quality, embryo implantation rate and clinical pregnancy rate were calculated.

RESULTSBesides very high proportion of round-headed sperm, partial globozoospermia also showed very high proportion of small-acrosomal sperm and very low proportion of morphologically normal sperm. Fertilization rate of IVF (IVF alone plus split IVF) was very low in partial globozoospermia (25.4% ± 17.4%), but ICSI (ICSI alone plus split ICSI) achieved satisfying fertilization rate compared with the control group (66.2% ± 22.5% vs. 68.8% ± 29.4%, P > 0.05). In patients with partial globozoospermia, there were no correlations between ICSI fertilization rate and the proportion of round-headed sperm, small-acrosomal sperm, or morphologically normal sperm.

CONCLUSIONSThere was high proportion of small-acrosomal sperm in partial globozoospermia. For patients with partial globozoospermia, ICSI is more preferable than IVF. ICSI fertilization rate does not depend on the proportion of round-headed sperm, small-acrosomal sperm, or morphologically normal sperm.

Adult ; Female ; Fertilization in Vitro ; Humans ; Infertility, Male ; therapy ; Male ; Pregnancy ; Sperm Injections, Intracytoplasmic ; Spermatozoa ; abnormalities ; cytology ; physiology