The placenta is a critical organ during pregnancy, essential for the provision of an optimal intrauterine environment, with fetal survival, growth, and development relying on correct placental function. It must allow nutritional compounds and relevant hormones to pass into the fetal bloodstream and metabolic waste products to be cleared. It also acts as a semipermeable barrier to potentially harmful chemicals, both endogenous and exogenous. Transporter proteins allow for bidirectional transport and are found in the syncytiotrophoblast of the placenta and endothelium of fetal capillaries. The major transporter families in the human placenta are ATP-binding cassette (ABC) and solute carrier (SLC), and insufficiency of these transporters may lead to deleterious effects on the fetus. Transporter expression levels are gestation-dependent and this is of considerable clinical interest as levels of drug resistance may be altered from one trimester to the next. This highlights the importance of these transporters in mediating correct and timely transplacental passage of essential compounds but also for efflux of potentially toxic drugs and xenobiotics. We review the current literature on placental molecular transporters with respect to their localization and ontogeny, the influence of fetal sex, and the relevance of animal models. We conclude that a paucity of information exists, and further studies are required to unlock the enigma of this dynamic organ.

Summary Sentence

This review summarises the existing knowledge of human placental molecular transporters (SLC and ABC superfamilies). We highlight areas where greater andmore accurate knowledge is required and discuss weaknesses of animal models for the human.

Colony-stimulating factor 2 (CSF2) is an embryokine that improves competence of the embryo to establish pregnancy and which may participate in developmental programming. We tested whether culture of bovine embryos with CSF2 alters fetal development and alleviates abnormalities associated with in vitro production (IVP) of embryos. Pregnancies were established by artificial insemination (AI), transfer of an IVP embryo (IVP), or transfer of an IVP embryo treated with 10 ng/ml CSF2 from day 5 to 7 of development (CSF2). Pregnancies were produced using X-sorted semen. Female singleton conceptuses were collected on day 86 of gestation. There were few morphological differences between groups, although IVP and CSF2 fetuses were heavier than AI fetuses. Bicarbonate concentration in allantoic fluid was lower for IVP than for AI or CSF2. Expression of 92 genes in liver, placenta, and muscle was determined. The general pattern for liver and placenta was for IVP to alter expression and for CSF2 to sometimes reverse this effect. For muscle, CSF2 affected gene expression but did not generally reverse effects of IVP. Levels of methylation for each of the three tissues at 12 loci in the promoter of insulin-like growth factor 2 (IGF2) and five in the promoter of growth factor receptor bound protein 10 were unaffected by treatment except for CSF2 effects on two CpG for IGF2 in placenta and muscle. In conclusion, CSF2 can act as a developmental programming agent but alone is not able to abolish the adverse effects of IVP on fetal characteristics.

Production of embryos in vitro (IVP) is associated with alterations in fetal morphology and gene expression at day 86 of gestation; addition of CSF2 to embryo culture altered features of the fetus but did not abolish abnormalities associated with IVP.

WD repeat-containing protein 5 (WDR5), a member of conserved WD40 protein family, is an essential component of the mixed lineage leukemia (MLL) complexes, which are crucial for numerous key biological processes including methylation of histone H3 lysine 4 (H3K4), self-renewal of embryonic stem cells, and formation of induced pluripotent stem cells. The expression pattern and functional role of WDR5 during porcine preimplantation embryonic development, however, remain unknown. Our results showed that the transcripts and protein of WDR5 exhibited stage-specific expression pattern in porcine early embryos. Moreover, blastocyst rate and total cell number per blastocyst were reduced by RNAi-mediated silencing of WDR5 or pharmacological inhibition of WDR5. Knockdown of WDR5 also disturbed the expression of several pluripotency genes. Interestingly, tri-methylation of H3K4 (H3K4me3) level was dramatically increased by WDR5 depletion. Further analysis revealed that loss of MLL3 phenocopied WDR5 knockdown, triggering increased H3K4me3 level. Simultaneously, WDR5 depletion significantly decreased the levels of histone H4 lysine 16 acetylation (H4K16ac) and its writer males absent on the first (MOF). Last but not least, WDR5 knockdown induced DNA damage and DNA repair defects during porcine preimplantation development. Taken together, results of described studies establish that WDR5 plays a significant role in porcine preimplantation embryos probably through regulating key epigenetic modifications and genome integrity.

Summary Sentence

WDR5 participates in the regulation of porcine embryonic development, likely mediated by regulation of epigenetic modifications (H3K4me3 and H4K16ac) and genome integrity.

The proteomic content of the endometrial fluid (EF) from patients with endometriosis has been investigated, but the lipidomic profile has not been analyzed yet in detail.

This study is a comparative untargeted lipidomic analysis of human EF obtained from 35 patients (12 endometriosis and 23 controls). Global differential lipidomic profile was analyzed in both groups by ultrahigh performance liquid chromatography coupled to mass spectrometry. A total of 123 out of the 457 metabolites identified in the EF were found to be significantly differentially expressed between ovarian endometriosis (OE) versus controls. Univariate statistical analysis showed reduced levels of saturated diacylglycerols and saturated triacylglycerols in endometriosis patients. A predictive model was generated using the 123 differentially expressed metabolites. Using this model, we were able to correctly classify 86% of the samples. This study identified the lipidomic profile in the EF associated with OE, suggesting that EF analysis could be considered as a minimally invasive approach for the diagnosis of endometriosis. In conclusion, the lipidomic profile of the EF is different between samples from patients with OE and controls.

Summary Sentence

The lipidomic profile of endometrial fluid in women with endometriosis is different from controls offering a novel opportunity for the minimally invasive diagnosis of endometriosis.

Eggs of teleost fish, unlike those of many other animals, allow sperm entry only at a single site, a narrow canal in the egg's chorion called the micropyle. In some fish (e.g., flounder, herring, and Alaska pollock), the micropyle is a narrow channel in the chorion, with or without a shallow depression around the outer opening of micropyle. In some other fish (e.g., salmon, pufferfish, cod, and medaka), the micropyle is like a funnel with a conical opening. Eggs of all the above fish have a glycoprotein tightly bound to the chorion surface around the micropyle. This glycoprotein directs spermatozoa into the micropylar canal in a Ca² -dependent manner. This substance, called the micropylar sperm attractant or MISA, increases fertilization efficiency and is essential in herring. In flounder, salmon, and perhaps medaka, fertilization is possible without MISA, but its absence makes fertilization inefficient because most spermatozoa swim over the micropyle without entering it. The mechanism underlying sperm-MISA interactions is yet to be determined, but at least in herring the involvement of Ca² and K channel proteins, as well as CatSper and adenylyl cyclase, is very likely. In some other fish (e.g., zebrafish, loach, and goldfish), the chorion around the micropyle is deeply indented (e.g., zebrafish and loach) or it has radially or spirally arranged grooves around the outer opening of the micropyle (e.g., goldfish). MISA is absent from the eggs of these fish and sperm entry into micropylar canal seems to be purely physical.

Summary Sentence

In fish, sperm entry into the egg through the micropyle is guided either chemically or physically depending on the species

The mitogen-activated protein kinase (MAPK), c-Jun N-terminal kinase (JNK), and p38 MAP kinase (p38) signaling cascades are involved in triggering apoptosis in somatic cells. Given that spermatozoa are able to undergo apoptosis, we tested the hypothesis that these pathways might be functional in ram spermatozoa as two signal transduction mechanisms that contribute to the modulation of capacitation and apoptosis. Indirect immunofluorescence and western blot analysis evidenced the presence of JNK and p38 in ram spermatozoa. To verify the involvement of these enzymes in sperm physiology, we determined the effect of specific inhibitors of JNK or p38 on in vitro capacitation induced with either cAMP-elevating agents or epidermal growth factor (EGF). Both inhibitions reduced the EGF-induced capacitation with a decrease in the chlortetracycline capacitated-sperm pattern, protein tyrosine phosphorylation, phosphatidylserine externalization, caspase-3 and -7 activation, and the proportion of DNA-damaged spermatozoa. No significant changes were found in the high-cAMP capacitated samples. The addition of 3.4 mg/ml seminal plasma proteins (SPPs) to the EGF-containing samples, either alone or together with each inhibitor, resulted in a decreased proportion of capacitated sperm pattern, protein tyrosine phosphorylation, loss of plasma membrane integrity, and apoptotic alterations. Furthermore, SPPs significantly reduced the phosphorylation level of JNK and p38 MAPK (active forms). These findings show a relationship between capacitation and apoptosis, and represent a step forward in the knowledge of the SPP protective mechanism in spermatozoa.

JNK and p38 MAPKs are activated during in vitro ram sperm capacitation with EGF, and seminal plasma proteins protect sperm not only acting at the plasma level but also by interfering with both MAPK pathways.

Spermatogonial stem cells must balance self-renewal with production of transit-amplifying progenitors that differentiate in response to retinoic acid (RA) before entering meiosis. This self-renewal vs. differentiation fate decision is critical for maintaining tissue homeostasis, as imbalances cause defects that can lead to human testicular cancer or infertility. Little is currently known about the program of differentiation initiated by RA, and the pathways and proteins involved are poorly defined. We recently found that RA stimulation of the Phosphatidylinositol 3-kinase (PI3K)/AKT/Mammalian target of rapamycin (mTOR) kinase signaling pathway is required for differentiation, and that short-term inhibition of mTOR complex 1 (mTORC1) by rapamycin blocked spermatogonial differentiation in vivo and prevented RA-induced translational activation. Since this phenotype resulted from global inhibition of mTORC1, we created conditional germ cell knockout mice to investigate the germ cell-autonomous role of MTOR in spermatogonial differentiation. MTOR germ cell KO mice were viable and healthy, but testes from neonatal (postnatal day (P)8), juvenile (P18), and adult (P > 60) KO mice were smaller than littermate controls, and no sperm were produced in adult testes. Histological and immunostaining analyses revealed that spermatogonial differentiation was blocked, and no spermatocytes were formed at any of the ages examined. Although spermatogonial proliferation was reduced in the neonatal testis, it was blocked altogether in the juvenile and adult testis. Importantly, a small population of self-renewing undifferentiated spermatogonia remained in adult testes. Taken together, these results reveal that MTOR is dispensable for the maintenance of undifferentiated spermatogonia, but is cell autonomously required for their proliferation and differentiation.

Germ cell specific Mtor knockout mice exhibit a phenotype in which spermatogonia self-renew in adult mice, but fail to proliferate, differentiate, and complete spermatogenesis.

During pregnancy, fetal extravillous trophoblasts (EVT) play a key role in the regulation of maternal T cell and NK cell responses. EVT display a unique combination of human leukocyte antigens (HLA); EVT do not express HLA-A and HLA-B, but do express HLA-C, HLA-E, and HLA-G. The mechanisms establishing this unique HLA expression pattern have not been fully elucidated. The major histocompatibility complex (MHC) class I and class II transcriptional activators NLRC5 and CIITA are expressed neither by EVT nor by the EVT model cell line JEG3, which has an MHC expression pattern identical to that of EVT. Therefore, other MHC regulators must be present to control HLA-C, HLA-E, and HLA-G expression in these cells. CIITA and NLRC5 are both members of the nucleotide-binding domain, leucine-rich repeat (NLR) family of proteins. Another member of this family, NLRP2, is highly expressed by EVT and JEG3, but not in maternal decidual stromal cells. In this study, transcription activator-like effector nuclease technology was used to delete NLRP2 in JEG3. Furthermore, lentiviral delivery of shRNA was used to knockdown NLRP2 in JEG3 and primary EVT. Upon NLRP2 deletion, Tumor Necrosis Factor-α (TNFα)-induced phosphorylation of NF-KB p65 increased in JEG3 and EVT, and more surprisingly a significant increase in constitutive HLA-C expression was observed in JEG3. These data suggest a broader role for NLR family members in the regulation of MHC expression during inflammation, thus forming a bridge between innate and adaptive immune responses. As suppressor of proinflammatory responses, NLRP2 may contribute to preventing unwanted antifetal responses.

Summary Sentence

By modulating the NF-KB pathway and HLA-C expression on human trophoblasts, NLRP2, may contribute to preventing detrimental inflammatory responses at the maternal-fetal interface.

The present studies were designed to determine whether progesterone (P4)-progesterone receptor membrane component 1 (PGRMC1) signaling is able to attenuate the apoptotic effects of oxidative stress induced by hydrogen peroxide (H₂O₂). To achieve this goal, freshly isolated human granulosa/ luteal cells were maintained in culture. After several passages, the cells were treated with H₂O₂, which induced apoptosis within 2.5 h, while simultaneous treatment with P4 attenuated the apoptotic action of H₂O₂. AG 205, a PGRMC1 antagonist, eliminated P4's ability to prevent H₂O₂-induced apoptosis. AG 205 neither affected PGRMC1's cytoplasmic localization nor its interaction with PGRMC2, but appeared to reduce its presence within the nucleus. AG 205 also (1) increased the monomeric and decreased the higher molecular weight forms of PGRMC1 (i.e., dimers/oligomers) and (2) altered the expression of several genes involved in apoptosis. The most dramatic change was an approximate 8-fold increase in Harakiri (Hrk) mRNA. However, AG 205 did not induce apoptosis in the absence of H₂O₂. Taken together, these observations suggest that the higher molecular weight forms of PGRMC1 likely account in part for PGRMC1's ability to suppress the expression of Hrk. Harakiri is a BH-3 only member of the B-cell lymphoma 2 (BCL2) family that promotes apoptosis by binding to and antagonizing the antiapoptotic action of BCL2- and BCL2-like proteins. It is likely then that PGRMC1's ability to suppress Hrk is part of the mechanism through which P4-PGRMC1 signaling preserves the viability of human granulosa/luteal cells.

Summary Sentence

The PGRMC1 antagonist, AG 205, blocks the ability of P4 to inhibit H₂O₂-induced apoptosis by disrupting PGRMC1 dimers/oligomers and inducing the expression of the apoptosis inducing BH3-only protein, Harakiri.

The developmental competence of an oocyte is its capacity to resume maturation, undergo successful fertilization, and reach the blastocyst stage. This competence is acquired through interaction with somatic cells of the follicle. Cumulus and granulosa cells support oocyte development, while the oocyte influences follicular cell growth and differentiation. Studies suggest that folliclestimulating hormone and luteinizing hormone play an essential role in oocyte competence acquisition through signaling initiated by protein kinases A and C (PKA and PKC) in granulosa cells. Using a microarray and RT-qPCR, the transcriptome of human granulosa-like tumor cells (KGN) treated for 24 h with forskolin (FSK) or phorbol 12-myristate 13-acetate (PMA) was analyzed to determine the effects of PKA and PKC stimulation on gene expression. Protein-kinase-driven signaling appeared to involve five major upstream regulators, namely epidermal growth factor (EGF), transforming growth factor beta 1 (TGFβ1), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF2), and hepatocyte growth factor (HGF). Gene associations with seven major ovarian functions were identified: Prostaglandin- endoperoxide synthase 2 (PTGS2), interleukin 8 (IL8), and interleukin 6 (IL6) with inflammation; Steroidogenic acute regulatory protein (STAR), cytochrome P450scc (CYP11A1), and cytochrome P450 family 19 subfamily Amember 1 (CYP19A1) with steroidogenesis; Vascular endothelial growth factor C (VEGFC), Vascular endothelial growth factor A (VEGFA), and C-X-C chemokine receptor type 4 (CXCR4) with angiogenesis; Amphiregulin (AREG), epidermal growth factor receptor (EGFR), and sprouty RTK signaling antagonist 2 (SPRY2) with differentiation, BCL2 associated X (BAX), BCL2 like 12 (BCL2L12), and caspase 1(CASP1) with apoptosis, Cyclin D1 (CCND1), cyclin B1 (CCNB1), and cyclin B2 (CCNB2) with division; and Matrix metalloproteinase-1 (MMP1), Matrix metallopeptidase 9 (MMP9), and TIMP metallopeptidase inhibitor 1 (TIMP1) with ovulation. Overall, these results indicate that signaling via both PKA and PKC potentiates gene regulation of functions such as inflammation and apoptosis, while functions such as differentiation, ovulation and angiogenesis are partial to one kinase or the other. These results improve understanding of the pathways underlying the most important changes that occur in the follicle prior to ovulation.

Protein kinase A and C signaling pathways play an important role in various major functions of ovarian follicle development such as cell differentiation, final maturation, luteinization, and ovulation.

Leptin regulates body weight, reproductive functions, blood pressure, endothelial function, and fetoplacental angiogenesis. Compared to the luteal phase, the follicular phase and pregnancy are physiological states of elevated estrogen, angiogenesis, and uterine blood flow (UBF). Little is known concerning regulation of uterine artery (UA) angiogenesis by leptin and its receptors. We hypothesized that (1) ex vivo expression of leptin receptors (LEPR) in UA endothelium (UAendo) and UA vascular smooth muscle (UAvsm) is elevated in pregnant versus nonpregnant (Luteal and Follicular) sheep; (2) in vitro leptin treatments differentially modulate mitogenesis in uterine artery endothelial cells from pregnant (P-UAECs) more than in nonpregnant (NP-UAECs) ewes; and (3) LEPR are upregulated in P-UAECs versus NP-UAECs in association with leptin activation of phospho-STAT3 signaling. Local UA adaptations were evaluated using a unilateral pregnant sheep modelwhere prebreeding uterine horn isolation (nongravid) restricted gravidity to one horn. Immunolocalization revealed LEPR in UAendo and UAvsm from pregnant and nonpregnant sheep. Contrary to our hypothesis, western analysis revealed that follicular UAendo and UAvsm LEPR were greater than luteal, nongravid, gravid, and control pregnant. Compared to pregnant groups, LEPR were elevated in renal artery endothelium of follicular and luteal sheep. Leptin treatment significantly increased mitogenesis in follicular phase NP-UAECs and P-UAECs, but not luteal phase NP-UAECs. Although UAEC expression of LEPR was similar between groups, leptin treatment only activated phospho-STAT3 in follicular NP-UAECs and P-UAECs. Thus, leptin may play an angiogenic role particularly in preparation for the increased UBF during the periovulatory period and subsequently to meet the demands of the growing fetus.

Summary Sentence

Leptin receptors are locally expressed in uterine artery endothelium and vascular smooth muscle cells during the ovarian cycle and late pregnancy. Leptin may play a role in regulating angiogenic responses of uterine artery endothelial cells during the follicular phase and late pregnancy.

Embryonic diapause is a period of developmental arrest which requires coordination of a molecular cross-talk between the endometrium and blastocyst to ensure a successful reactivation, but the exact mechanisms are undefined. The objectives of this study were to screen the tammar blastocyst for potential diapause control factors and to investigate the potential for members of the epidermal growth factor (EGF) family to coordinate reactivation. A select number of factors were also examined in the mink to determine whether their expression patterns were conserved across diapause species. The full-length sequences of the tammar genes of interest were first cloned to establish their level of sequence conservation with other mammals. The uterine expression of EGF family members EGF and heparin-binding EGF (HBEGF) and their receptors (EGFR and erb-b2 receptor tyrosine kinase 4 (ERBB4)) was determined by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry. Both HBEGF and EGF were significantly upregulated at reactivation compared to diapause. In the blastocyst, the expression of the potential diapause factors Forkhead box class O family members (FOXO1, FOXO3, and FOXO4), tumor protein 53 (TP53), cyclin-dependent kinase inhibitor 1A (CDKN1A), and the EGF family were examined by RT-PCR and immunofluorescence. Nuclear (and hence active) FOXO expression was confirmed for the first time in a mammalian diapause blastocyst in both the tammar and the mink—CDKN1A was also expressed, but TP53 is not involved and EGFR was not detected in the blastocyst. These results indicate that the EGF family, FOXOs, and CDKN1A are promising candidates for the molecular control of embryonic diapause in mammals.

The FOXOs and CDKN1A are potential novel candidates tomaintain the blastocyst during diapause and the EGF family is confirmed in two species to be specifically expressed at reactivation from diapause.

The peptide relaxin has gained considerable attention as a new vasoactive drug, largely through its beneficial therapeutic effects in cardiovascular disease. In this study, we tested the hypothesis that relaxin treatment alleviates systemic vascular dysfunction characteristic of hypertensive diseases of pregnancy. We investigated vascular effects and mechanisms of relaxin action in (i) pregnant relaxin-deficient (Rln^-/-) mice with enhanced responses to angiotensin II (AngII) and (ii) arteries pre-incubated ex vivo in trophoblast conditioned media (TCM) to induce endothelial dysfunction. Pregnant Rln^-/- mice received 0.5 µg/h recombinant human H2 relaxin (rhRLX: n = 5) or placebo (20 nM sodium acetate; n = 7) subcutaneously via osmotic minipumps for 5 days prior to gestational day 17.5. This treatment protocol significantly reduced AngII-mediated contraction of mesenteric arteries and increased plasma 6-keto prostaglandin F_1α. These vascular effects were endothelium independent and likely involve smooth muscle-derived vasodilator prostanoids. In the second study, mesenteric arteries were incubated ex vivo for 24 h at 37°C in TCM, which contained high levels of soluble Flt-1 (>20 ng/ml) and soluble Eng (>1 ng/ml). TCM incubation caused significant reduction in endothelium-dependent relaxation and increased sensitivity to AngII. Coincubation of arteries with rhRLX for 24 h (n = 6–16/treatment) prevented endothelial dysfunction but had no effect on AngII-mediated contraction. In conclusion, relaxin treatment prevents and/or reverses vascular dysfunction in mesenteric arteries, but acts through different vascular pathways depending on duration of relaxin treatment and type of vascular dysfunction. Overall, our data suggest that relaxin is a potential therapeutic to alleviate maternal systemic vascular dysfunction associated with hypertensive diseases in pregnant women.

Relaxin treatment reduces the vasoconstriction of the mesenteric artery to angiotensin II and protects the vasculature from developing endothelial dysfunction.

Sperm motility is an important standard to measure the fertility of male. In our previous study, we found that the diploid spermatozoa from allotetraploid hybrid (4nAT) had longer durations of rapid and slow progressive motility than haploid spermatozoa from common carp (COC). In this study, to explore sperm motility-related molecular mechanisms, we compared the testis tissues transcriptomes from 2-year-old male COC and 4nAT. The RNA-seq data revealed that 2985 genes were differentially expressed between COC and 4nAT, including 2216 upregulated and 769 downregulated genes in 4nAT. Some differentially expressed genes, such as tubulin genes, dynein, axonemal, heavy chain(dnah) genes, mitogen-activated protein kinase(mapk) genes, tektin 4, FOX transcription factors, proteasome genes, and ubiquitin carboxyl-terminal hydrolase(uchl) genes, are involved in the regulation of cell division, flagellar and ciliary motility, gene transcription, cytoskeleton, energy metabolism, and the ubiquitin-proteasome system, suggesting that these genes were related to sperm motility of the 4nAT. We confirmed the differential expression of 12 such genes in 4nAT by quantitative PCR. By western blotting, we also confirmed increased expression of Uchl3 in 4nAT testis. In addition, we identified 1915 and 2551 predicted long noncoding RNA (lncRNA) transcripts from testis tissue transcriptomes of COC and 4nAT, respectively. Of these, 1575 lncRNAs were specifically expressed in 4nAT and 939 were specifically expressed in COC. This study provides insights into the transcriptome profile of testis tissues from diploid and tetraploid, which are useful for research on regulatorymechanisms behind sperm motility in male polyploidy.

Summary Sentence

Clues of variations in tetraploid testis are characterized by comparative transcriptome analysis between tetraploid hybrid and common carp.

Acrylamide is a ubiquitous toxicant in human lives, due to its formation in many food products. Acrylamide induces dominant lethal mutations with administration of 25 mg/kg bw/day for 5 days in male mice. Cytochrome P450, family 2, subfamily E, polypeptide 1 (CYP2E1) is responsible for this dominant lethality. CYP2E1 is the only enzyme responsible for the conversion of acrylamide to the highly reactive metabolite glycidamide, which forms adducts with DNA. CYP2E1 is present predominantly in the liver, as well as the brain, kidney, intestines, and spleen. Within the male mouse reproductive tract, CYP2E1 localizes to spermatocytes. However, embryo resorptions have been demonstrated to occur only with exposure of the late stages of spermatogenesis and spermatozoa. It was determined that CYP2E1 is additionally expressed within the mouse epididymal epithelium, and this localization is responsible for acrylamide-induced dominant lethality. Further, an equivalent profile of CYP2E1 expression was identified in the human reproductive tract. While spermatozoa of both species were also established to possess CYP2E1, this did not contribute to acrylamide-induced DNA damage. In vitro studies strengthened these findings further, revealing that acrylamide exposure only induces DNA damage in human and mouse spermatozoa following metabolism by the mouse epididymal epithelial cell line (mECap18) to glycidamide. These findings emphasize, for the first time, the vital role of the epididymis in the reproductive toxicity associated with acute acrylamide exposure.

While CYP2E1, the enzyme responsible for metabolizing acrylamide, is expressed in spermatocytes and spermatozoa, epididymal CYP2E1 activity is crucial in instigating DNA damage that results in dominant lethality following acute acrylamide exposure.

“Relative contribution of clear cells and principal cells to luminal pH in the mouse epididymis” (DOI: 10.1095/biolreprod.116.144857) Biology of Reproduction Volume 96, Issue 2, pp. 366–375, February 2017. Due to a typographical error Bongki Kim's name was misspelled as BongKi Kim. The author regrets the error.

The original article published in Biology of Reproduction; doi:10.1093/biolre/iox008 An incorrect version of this article was received into production and published as an Accepted Manuscript. We have replaced the incorrect Accepted Manuscript with this correct version. The publisher regrets the error. © The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com