Inflammaging is a state of chronic, low-grade inflammation associated with aging which contributes to age-related diseases. Recently, an age-associated increase in inflammation has been documented in the mammalian ovary, which is accompanied by a shift in the immune cell profile. In this Point of View article, we consider a unique population of macrophage-derived multinucleated giant cells, found in reproductively old mouse ovaries, as potential markers or functional drivers of inflammation in ovarian aging.
K Grace Foley, Michele T Pritchard, and Francesca E Duncan
Leelabati Biswas, Katarzyna Tyc, Warif El Yakoubi, Katie Morgan, Jinchuan Xing, and Karen Schindler
Idiopathic or ‘unexplained’ infertility represents as many as 30% of infertility cases worldwide. Conception, implantation, and term delivery of developmentally healthy infants require chromosomally normal (euploid) eggs and sperm. The crux of euploid egg production is error-free meiosis. Pathologic genetic variants dysregulate meiotic processes that occur during prophase I, meiotic resumption, chromosome segregation, and in cell cycle regulation. This dysregulation can result in chromosomally abnormal (aneuploid) eggs. In turn, egg aneuploidy leads to a broad range of clinical infertility phenotypes, including primary ovarian insufficiency and early menopause, egg fertilization failure and embryonic developmental arrest, or recurrent pregnancy loss. Therefore, maternal genetic variants are emerging as infertility biomarkers, which could allow informed reproductive decision-making. Here, we select and deeply examine human genetic variants that likely cause dysregulation of critical meiotic processes in 14 female infertility-associated genes: SYCP3, SYCE1, TRIP13, PSMC3IP, DMC1, MCM8, MCM9, STAG3, PATL2, TUBB8, CEP120, AURKB, AURKC, andWEE2. We discuss the function of each gene in meiosis, explore genotype-phenotype relationships, and delineate the frequencies of infertility-associated variants.
C H K Hughes, A Rogus, E K Inskeep, and J L Pate
Progesterone, which is secreted from the corpus luteum, is indispensable for the establishment and maintenance of pregnancy. The orphan nuclear receptor subfamily 5 group A member 2 (NR5A2) is a regulator of murine luteinization, but neither its regulation nor its role in the fully differentiated, mature corpus luteum (CL) have been described. Therefore, the goal of this study was to profile abundance and investigate the regulation and functions of NR5A2 in the bovine CL. Treatment of cultured luteal steroidogenic cells with a pharmacological inhibitor of NR5A2 decreased progesterone production and tended to decrease abundance of HSD3B1 mRNA. Luteal NR5A2 mRNA increased and NR5A2 protein tended to increase between days 4 and 6 of the estrous cycle, coincident with increased steroidogenic capacity of the CL. Luteal NR5A2 mRNA decreased by 8 h after prostaglandin (PG) F2A injection. During early pregnancy, luteal NR5A2 mRNA was less on days 20 and 23 compared to day 14, but protein abundance did not change. Neither 1 nor 10 ng/mL interferon tau (IFNT) altered NR5A2 abundance in cultured luteal steroidogenic cells, but 10 ng/mL PGF2A decreased NR5A2. Because of discrepancies between mRNA and protein abundance of NR5A2, regulation by miRNA that changed during early pregnancy was investigated. miR-27b-3p, miR-432-5p, and miR-369-3p mimics decreased NR5A2 protein abundance and miR-369-3p also inhibited progesterone production. Overall, the results of this study show that NR5A2 may be maintained by miRNA during early pregnancy and may be an important regulator of luteal progesterone production.
Daqian Dong, Jinmeng Yang, Yining Chen, Guofan Peng, Heran Cao, Huihui Gao, Tianqi Jin, Fangxia Yang, and Wuzi Dong
Epididymal specific proteins play a crucial role in sperm maturation. Some of the post-translational modified proteins are transported from the caput to the cauda of the epididymis through exosomes which regulate the function of sperm in cauda epididymis. Rat beta-galactosidase-1-like protein 4 (GLB1L4) expressed specifically in the caput epididymis, localizes on the sperm; however, the regulatory ways in which GLB1L4 protein interacts with sperm to maintain sperm function are unclear. In this study, knockdown of rat GLB1L4 could inhibit in vitro capacitation of sperm in cauda epididymis and reduce the fertility of the male rats by injection of special lentivirus-shRNA into caput epididymis. Moreover, a considerable proportion of GLB1L4 proteins from rat caput epididymis were loaded on exosomes. The exosomes loaded GLB1L4 from in vitro primary rat caput epididymal epithelial cells could bind with spermatozoa in cauda epididymis. Further, the palmitoylation status of cysteine residues at the 12th and 15th sites of the protein molecule could significantly affect cellular localization of GLB1L4 protein. It was identified that most of GLB1L4 was palmitoylated in the presence of exosomes from primary caput epididymal cells and the level of palmitoylated GLB1L4 in the exosomes could be inhibited by 2-bromopalmitate (2-BP). These results suggested that the palmitoylated GLB1L4 from rat caput epididymis could be transported to the cauda epididymis to regulate the sperm function by exosomes.
Vanessa Caroline Fioravante, Alana Rezende Godoi, Victória Mokarzel de Barros Camargo, Renata Steffany do Nascimento, Patricia Fernanda Felipe Pinheiro, and Francisco Eduardo Martinez
Parental ethanol consumption can influence the offspring phenotype. In this way, we analyzed the impairments of maternal and paternal high ethanol consumption during postpuberty on the physical development, feeding pattern, puberty onset and reproductive function of ethanol-naive offspring to birth to adulthood. Female and male UChB rats (voluntary 10%, v/v ethanol consumer) were divided into a control group (C) and an ethanol exposed group (E) from 65 to 80 days of age. The C and E were mated at 100 days. The maternal parameters and offspring development and reproduction parameters were monitored. We observed reduced feeding intake and body weight in the dams of E group throughout gestation and lactation period. Delay in physical development, lower body weight and altered feeding pattern were observed in female and male offspring of E group. In addition, the puberty onset was delayed in both sexes, with lower testosterone levels in the juvenile and pubertal males. There was a prolongation on the estrous and proestrus phases in females from E but the estrous cycle duration did not change between groups. Ovary and uterus weight were reduced in pubertal and adult females from E group. Reduced epididymis and seminal vesicle weight, increased sperm abnormalities, decrease in the daily sperm production and accelerated epididymal transit time were observed in E males. The high maternal and paternal ethanol use on postpuberty impairs the parameters of ethanol-naive offspring inducing alteration on development and reproduction.
Harleen Kaur, Alison S Care, Rebecca L Wilson, Sandra G Piltz, Paul Q Thomas, Beverly S Muhlhausler, Claire T Roberts, and Kathryn L Gatford
Animal models are needed to develop interventions to prevent or treat intrauterine growth restriction (IUGR). Foetal growth rates and effects of in utero exposures differ between sexes, but little is known about sex-specific effects of increasing litter size. We established a murine IUGR model using pregnancies generated by multiple embryo transfers, and evaluated sex-specific responses to increasing litter size. CBAF1 embryos were collected at gestation day 0.5 (GD0.5) and 6, 8, 10 or 12 embryos were transferred into each uterine horn of pseudopregnant female CD1 mice (n = 32). Foetal and placental outcomes were measured at GD18.5. In the main experiment, foetuses were genotyped (Sry) for analysis of sex-specific outcomes. The number of implantation sites (P = 0.033) and litter size (number of foetuses, P = 0.008) correlated positively with the number of embryos transferred, while placental weight correlated negatively with litter size (both P < 0.01). The relationship between viable litter size and foetal weight differed between sexes (interaction P = 0.002), such that foetal weights of males (P = 0.002), but not females (P = 0.233), correlated negatively with litter size. Placental weight decreased with increasing litter size (P < 0.001) and was lower in females than males (P = 0.020). Our results suggest that male foetuses grow as fast as permitted by nutrient supply, whereas the female maintains placental reserve capacity. This strategy reflecting sex-specific gene expression is likely to place the male foetus at greater risk of death in the event of a ‘second hit’.
Ejimedo Madogwe, Yasmin Schuermann, Dayananda Siddappa, Vilceu Bordignon, Philippe P Roux, and Raj Duggavathi
Abolition of the LH-induced ERK1/2 pathway leads to dramatic changes in gene expression in granulosa cells, subsequently abrogating ovulation. Here we explored whether sustained ERK1/2 signaling beyond immediate-early hours of the LH surge is important for ovulation in mice. First, we examined the effect of inhibition of ERK1/2 activity at 4 h after hCG stimulation on ovulation in superovulated immature mice. Treatment with the ERK1/2 pathway inhibitor PD0325901 at 4 h post-hCG disrupted follicular rupture without altering cumulus expansion, oocyte meiotic maturation and luteinization. Profiling the expression pattern of genes of the RSK family of ERK1/2 signal mediators revealed that RSK3, but not other isoforms, was induced by hCG treatment. Further, RSK3-knockout mice were sub-fertile with reduced ovulation rate and smaller litter size compared to WT mice. Given that PD0325901 inhibits all mediators of ERK1/2 signaling, we chose to evaluate the gene expression underlying deficient follicular rupture in ERK1/2 inhibited mice. We found that inhibition of ERK1/2 signaling at 4 h post-hCG resulted in an imbalance in the expression of genes involved in extracellular matrix degradation and leukocyte infiltration necessary for follicular rupture. In conclusion, our data demonstrate that sustained ERK1/2 signaling during ovulation is not required for cumulus expansion, oocyte meiotic maturation and luteinization, but is required for follicular rupture.
Magdalena Kotlarska, Dawid Winiarczyk, Wiesława Florek, Marta Ziętek, Jolanta Pęczkowicz-Szyszka, Adrian Mateusz Stankiewicz, Rafał Radosław Starzyński, Roberta Arena, Gaspare Drago, Silvestre Sampino, and Jacek Andrzej Modlinski
Preimplantation embryos are particularly vulnerable to environmental perturbations, including those related to assisted reproductive technologies. Invasive embryo manipulations, such as blastomere biopsy, are applied worldwide in clinical settings for preimplantation genetic testing. Mouse models have previously shown that blastomere biopsy may be associated with altered phenotypes in adult offspring. The aim of the present study was to investigate the specific contribution of blastomere removal to the physiological, behavioral, and molecular regulators of energy homeostasis, as compared to sham manipulation (re-introducing the blastomere into the embryo after its removal) and in vitro culture. Mice derived from 8-cell embryos subjected to blastomere removal displayed: (i) higher body weight and adiposity, (ii) increased food intake and sucrose preference, (iii) decreased time of immobility in the tail suspension test, and (iv) resistance to weight loss after social isolation or following 3 days of physical exercise – compared to mice derived from sham biopsy or from in vitro-cultured embryos. Mice generated after blastomere removal also had increased circulating leptin and leptin gene expression in adipose tissue, as well as increased ghrelin receptor gene expression in the hypothalamus, compared to control mice. The effects of blastomere biopsy on offspring phenotype were sexually dimorphic, with females not being affected. These results indicate that blastomere deprivation, rather than other perturbations of the blastomere biopsy procedure, programs male embryos to develop physiological, behavioral, and molecular dysregulation of energy homeostasis, leading to postnatal obesity.
Deepak S Hiremath, Fernanda B M Priviero, R Clinton Webb, CheMyong Ko, and Prema Narayan
Timely activation of the luteinizing hormone receptor (LHCGR) is critical for fertility. Activating mutations in LHCGR cause familial male-limited precocious puberty (FMPP) due to premature synthesis of testosterone. A mouse model of FMPP (KiLHRD582G), expressing a constitutively activating mutation in LHCGR, was previously developed in our laboratory. KiLHRD582G mice became progressively infertile due to sexual dysfunction and exhibited smooth muscle loss and chondrocyte accumulation in the penis. In this study, we tested the hypothesis that KiLHRD582G mice had erectile dysfunction due to impaired smooth muscle function. Apomorphine-induced erection studies determined that KiLHRD582G mice had erectile dysfunction. Penile smooth muscle and endothelial function were assessed using penile cavernosal strips. Penile endothelial cell content was not changed in KiLHRD582G mice. The maximal relaxation response to acetylcholine and the nitric oxide donor, sodium nitroprusside, was significantly reduced in KiLHRD582G mice indicating an impairment in the nitric oxide (NO)-mediated signaling. Cyclic GMP (cGMP) levels were significantly reduced in KiLHRD582G mice in response to acetylcholine, sodium nitroprusside and the soluble guanylate cyclase stimulator, BAY 41-2272. Expression of NOS1, NOS3 and PKRG1 were unchanged. The Rho-kinase signaling pathway for smooth muscle contraction was not altered. Together, these data indicate that KiLHRD582G mice have erectile dysfunction due to impaired NO-mediated activation of soluble guanylate cyclase resulting in decreased levels of cGMP and penile smooth muscle relaxation. These studies in the KiLHRD582G mice demonstrate that activating mutations in the mouse LHCGR cause erectile dysfunction due to impairment of the NO-mediated signaling pathway in the penile smooth muscle.