Reproductive biologies
Abstract
Exposure to maternal obesity may promote metabolic dysfunction in offspring. We use infant mesenchymal stem cells (MSC) to experimentally examine cellular mechanisms of intergenerational health transmission. Our earlier reports show MSCs collected from infants of mothers with obesity had a dichotomous distribution in metabolic efficiency; they were either efficient (Ef-Ob) or inefficient (In-Ob) with respect to fatty acid oxidation (FAO). Here, we sought to determine if this was due to a primary defect in FAO. Accordingly, we measured FAO in myogenic differentiating MSCs under three conditions: 1) myogenesis alone, 2) excess fatty acid exposure, and 3) excess fatty acid exposure plus a chemical uncoupler to increase metabolic rate. Compared to NW and Ef-Ob MSCs, In-Ob displayed lower FAO in myogenesis alone and after fatty acid plus uncoupler, indicating In-Ob were less metabolically flexible after increasing lipid availability and metabolic rate, demonstrating a primary deficit in FAO. MSC FAO was negatively associated with fasting maternal glucose and insulin, and positively associated with fasting HDL-cholesterol. MSC FAO was negatively associated with infant fat mass. These data indicate a less favorable maternal metabolic milieu, independent of maternal BMI, reduces intrinsic MSC FAO and is linked to higher infant adiposity as early as birth.
Authors
Melissa L. Erickson, Zachary W. Patinkin, Allison M. Duensing, Dana Dabelea, Leanne M. Redman, Kristen E. Boyle
Abstract
Clinical phenotyping of term and preterm labor is imprecise, and disagreement persists on categorization relative to underlying pathobiology, which remains poorly understood. We performed RNA sequencing (RNA-seq) of 31 specimens of human uterine myometrium from 10 term and 21 preterm cesarean deliveries with rich clinical context information. A molecular signature of 4,814 transcripts stratified myometrial samples into quiescent (Q) and non-quiescent (NQ) phenotypes, independent of gestational age and incision site. Similar stratifications were achieved using expressed genes in Ca2+ signaling and TGF-β pathways. For maximal parsimony, we evaluated the expression of just two Ca2+ transporter genes, ATP2B4 (encoding PMCA4) and ATP2A2 (coding for SERCA2), and found that their ratio reliably distinguished NQ and Q specimens in the current study, and also in two publically available RNA-seq datasets (GSE50599 and GSE80172), with an overall AUC of 0.94. Cross-validation of the ATP2B4/ATP2A2 ratio by qPCR in an expanded cohort (by 11 additional specimens) achieved complete separation (AUC=1.00) of NQ vs. Q specimens. While providing additional insight into the associations between clinical features of term and preterm labor and myometrial gene expression, our study also offers a practical algorithm for unbiased classification of myometrial biopsies by their overall contractile program.
Authors
William E. Ackerman IV, Catalin S. Buhimschi, Ali Snedden, Taryn L. Summerfield, Guomao Zhao, Irina A. Buhimschi
Abstract
The microtubule (MT) cytoskeleton plays a critical role in axon growth and guidance. Here, we identify the MT severing enzyme fidgetin-like 2 (FL2) as a negative regulator of axon regeneration and a therapeutic target for promoting nerve regeneration after injury. Genetic knockout of FL2 in cultured adult dorsal root ganglion (DRG) neurons resulted in longer axons and attenuated growth cone retraction in response to inhibitory molecules. Given the axonal growth-promoting effects of FL2 depletion in vitro, we tested whether FL2 could be targeted to promote regeneration in a rodent model of cavernous nerve (CN) injury. The CN are parasympathetic nerves that regulate blood flow to the penis, which are commonly damaged during radical prostatectomy (RP) resulting in erectile dysfunction (ED). Application of FL2-siRNA after CN injury significantly enhanced functional nerve recovery. Remarkably, following bilateral nerve transection, visible and functional nerve regeneration was observed in 7 out of 8 animals treated with FL2-siRNA, while no control treated animals exhibited regeneration. These studies identify FL2 as a promising therapeutic target for enhancing regeneration after peripheral nerve injury and for mitigating neurogenic ED post-RP—a condition for which, at present, only poor treatment options exist.
Authors
Lisa Baker, Moses Tar, Adam H. Kramer, Guillermo A. Villegas, Rabab A. Charafeddine, Olga Vafaeva, Parimala Nacharaju, Joel Friedman, Kelvin P. Davies, David J. Sharp
Abstract
A maternal Western-style diet (WSD) is associated with poor reproductive outcomes, but whether this is from the diet itself or underlying metabolic dysfunction is unknown. Here, we performed a longitudinal study using regularly cycling female rhesus macaques (n = 10) that underwent 2 consecutive in vitro fertilization (IVF) cycles, one while consuming a low-fat diet and another 6–8 months after consuming a high-fat WSD. Metabolic data were collected from the females prior to each IVF cycle. Follicular fluid (FF) and oocytes were assessed for cytokine/steroid levels and IVF potential, respectively. Although transition to a WSD led to weight gain and increased body fat, no difference in insulin levels was observed. A significant decrease in IL-1RA concentration and the ratio of cortisol/cortisone was detected in FF after WSD intake. Despite an increased probability of isolating mature oocytes, a 44% reduction in blastocyst number was observed with WSD consumption, and time-lapse imaging revealed delayed mitotic timing and multipolar divisions. RNA sequencing of blastocysts demonstrated dysregulation of genes involved in RNA binding, protein channel activity, mitochondrial function and pluripotency versus cell differentiation after WSD consumption. Thus, short-term WSD consumption promotes a proinflammatory intrafollicular microenvironment that is associated with impaired preimplantation development in the absence of large-scale metabolic changes.
Authors
Sweta Ravisankar, Alison Y. Ting, Melinda J. Murphy, Nash Redmayne, Dorothy Wang, Carrie A. McArthur, Diana L. Takahashi, Paul Kievit, Shawn L. Chavez, Jon D. Hennebold
Abstract
The pathogenesis of preeclampsia and other hypertensive disorders of pregnancy remains poorly-defined despite the substantial burden of maternal and neonatal morbidity associated with these conditions. In particular, the role of genetic variants as determinants of disease susceptibility remains unknown. Storkhead-box protein 1 (STOX1) was first identified as a preeclampsia risk gene through family-based genetic linkage studies in which loss-of-function variants were proposed to underlie increased preeclampsia susceptibility. We generated a genetic Stox1 loss-of-function mouse model (Stox1 KO), to evaluate whether STOX1 regulates blood pressure in pregnancy. Pregnant Stox1 KO mice developed gestational hypertension evidenced by a significant increase in blood pressure compared with wild type by E17.5. While severe renal, placental, or fetal growth abnormalities were not observed, the Stox1 KO phenotype was associated with placental vascular and extracellular matrix abnormalities. Mechanistically, we found that gestational hypertension in Stox1 KO mice resulted from activation of the uteroplacental renin-angiotensin system. We confirmed this mechanism by showing that treatment of pregnant Stox1 KO mice with an angiotensin II receptor blocker rescued the phenotype. Our study demonstrates the utility of genetic mouse models for uncovering links between genetic variants and effector pathways implicated in the pathogenesis of hypertensive disorders of pregnancy.
Authors
Jacqueline G. Parchem, Keizo Kanasaki, Soo Bong Lee, Megumi Kanasaki, Joyce L. Yang, Yong Xu, Kadeshia M. Earl, Rachel A. Keuls, Vincent H. Gattone, Raghu Kalluri
Abstract
Successful implantation is associated with a unique spatial pattern of vascular remodeling, characterized by profound peripheral neovascularization surrounding a periembryo avascular niche. We hypothesized that hyaluronan controls the formation of this distinctive vascular pattern encompassing the embryo. This hypothesis was evaluated by genetic modification of hyaluronan metabolism, specifically targeted to embryonic trophoblast cells. The outcome of altered hyaluronan deposition on uterine vascular remodeling and postimplantation development were analyzed by MRI, detailed histological examinations, and RNA sequencing of uterine NK cells. Our experiments revealed that disruption of hyaluronan synthesis, as well as its increased cleavage at the embryonic niche, impaired implantation by induction of decidual vascular permeability, defective vascular sinus folds formation, breach of the maternal-embryo barrier, elevated MMP-9 expression, and interrupted uterine NK cell recruitment and function. Conversely, enhanced deposition of hyaluronan resulted in the expansion of the maternal-embryo barrier and increased diffusion distance, leading to compromised implantation. The deposition of hyaluronan at the embryonic niche is regulated by progesterone-progesterone receptor signaling. These results demonstrate a pivotal role for hyaluronan in successful pregnancy by fine-tuning the periembryo avascular niche and maternal vascular morphogenesis.
Authors
Ron Hadas, Eran Gershon, Aviad Cohen, Ofir Atrakchi, Shlomi Lazar, Ofra Golani, Bareket Dassa, Michal Elbaz, Gadi Cohen, Raya Eilam, Nava Dekel, Michal Neeman
Abstract
Metabolic syndrome (MetS), which is associated with chronic inflammation, predisposes males to hypogonadism and subfertility. The underlying mechanism of these pathologies remains poorly understood. Homozygous leptin-resistant obese db/db mice are characterized by small testes, low testicular testosterone, and a reduced number of Leydig cells. Here we report that IL-1β, CCL2 (also known as MCP-1), and corticosterone concentrations were increased in the testes of db/db mice relative to those in WT controls. Cultured murine and human Leydig cells responded to cytokine stress with increased CCL2 release and apoptotic signals. Chemical inhibition of CCL2 rescued Leydig cell function in vitro and in db/db mice. Consistently, we found that Ccl2-deficient mice fed with a high-energy diet were protected from testicular dysfunction compared with similarly fed WT mice. Finally, a cohort of infertile men with a history of MetS showed that reduction of CCL2 plasma levels could be achieved by weight loss and was clearly associated with recovery from hypogonadism. Taken together, we conclude that CCL2-mediated chronic inflammation is, to a large extent, responsible for the subfertility in MetS by causing damage to Leydig cells.
Authors
Qingkui Jiang, Constanze C. Maresch, Sebastian Friedrich Petry, Agnieszka Paradowska-Dogan, Sudhanshu Bhushan, Yongsheng Chang, Christine Wrenzycki, Hans-Christian Schuppe, Petr Houska, Michaela F. Hartmann, Stefan A. Wudy, Lanbo Shi, Thomas Linn
Abstract
WNK1 is an atypical kinase protein ubiquitously expressed in humans and mice. A mutation in its encoding gene causes hypertension in humans which is associated with abnormal ion homeostasis. WNK1 is critical for in vitro decidualization in human endometrial stromal cells, thereby demonstrating its importance in female reproduction. Using a mouse model, WNK1 was ablated in the female reproductive tract to define its in vivo role in uterine biology. Loss of WNK1 altered uterine morphology, causing endometrial epithelial hyperplasia, adenomyotic features and a delay in embryo implantation, ultimately resulting in compromised fertility. Combining transcriptomic, proteomic and interactomic analyses revealed a novel regulatory pathway whereby WNK1 represses AKT phosphorylation through the phosphatase PP2A in endometrial cells from both humans and mice. We show that WNK1 interacts with PPP2R1A, the alpha isoform of the PP2A scaffold subunit. This maintains the levels of PP2A subunits and stabilizes its activity, which then dephosphorylates AKT. Therefore, loss of WNK1 reduced PP2A activity, causing AKT hypersignaling. Using FOXO1 as a readout of AKT activity, we demonstrate that there was escalated FOXO1 phosphorylation and nuclear exclusion, leading to a disruption in the expression of genes that are crucial for embryo implantation.
Authors
Ru-pin Alicia Chi, Tianyuan Wang, Chou-Long Huang, San-Pin Wu, Steven Young, John Lydon, Francesco DeMayo
Human Tregs at the maternal-fetal interface show site-specific adaptation reminiscent of tumor Tregs
Abstract
Regulatory T cells (Tregs) are crucial for maintaining maternal immune-tolerance against the semi-allogeneic fetus. We investigated the elusive transcriptional profile and functional adaptation of human uterine Tregs (uTregs) during pregnancy. Uterine biopsies, from placental bed (=maternal-fetal interface) and incision site (=control), and blood were obtained from women with uneventful pregnancies undergoing Caesarean section. Tregs and CD4+ non-Tregs were isolated for transcriptomic profiling by Cel-Seq2. Results were validated on protein and single cell level by flow cytometry. Placental bed uterine Tregs (uTregs) showed elevated expression of Treg signature markers, including FOXP3, CTLA-4 and TIGIT. Their transcriptional profile was indicative of late-stage effector Treg differentiation and chronic activation, with increased expression of immune checkpoints GITR, TNFR2, OX-40, 4-1BB, genes associated with suppressive capacity (HAVCR2, IL10, LAYN, PDCD1), and transcription factors MAF, PRDM1, BATF, and VDR. uTregs mirrored non-Treg Th1 polarization and tissue-residency. The particular transcriptional signature of placental bed uTregs overlapped strongly with that of tumor-infiltrating Tregs, and was remarkably pronounced at the placental bed compared to uterine control site. Concluding, human uTregs acquire a differentiated effector Treg profile similar to tumor-infiltrating Tregs, specifically at the maternal-fetal interface. This introduces the novel concept of site-specific transcriptional adaptation of Tregs within one organ.
Authors
Judith Wienke, Laura Brouwers, Leone M. van der Burg, Michal Mokry, Rianne C. Scholman, Peter G. J. Nikkels, Bas B. van Rijn, Femke van Wijk
Abstract
The initiation of puberty is driven by an upsurge in hypothalamic gonadotropin-releasing hormone (GnRH) secretion. In turn, GnRH secretion upsurge depends on the development of a complex GnRH neuroendocrine network during embryonic life. Although delayed puberty (DP) affects up to 2% of the population, is highly heritable, and is associated with adverse health outcomes, the genes underlying DP remain largely unknown. We aimed to discover regulators by whole-exome sequencing of 160 individuals of 67 multigenerational families in our large, accurately phenotyped DP cohort. LGR4 was the only gene remaining after analysis that was significantly enriched for potentially pathogenic, rare variants in 6 probands. Expression analysis identified specific Lgr4 expression at the site of GnRH neuron development. LGR4 mutant proteins showed impaired Wnt/β-catenin signaling, owing to defective protein expression, trafficking, and degradation. Mice deficient in Lgr4 had significantly delayed onset of puberty and fewer GnRH neurons compared with WT, whereas lgr4 knockdown in zebrafish embryos prevented formation and migration of GnRH neurons. Further, genetic lineage tracing showed strong Lgr4-mediated Wnt/β-catenin signaling pathway activation during GnRH neuron development. In conclusion, our results show that LGR4 deficiency impairs Wnt/β-catenin signaling with observed defects in GnRH neuron development, resulting in a DP phenotype.
Authors
Alessandra Mancini, Sasha R. Howard, Federica Marelli, Claudia P. Cabrera, Michael R. Barnes, Michael J.E. Sternberg, Morgane Leprovots, Irene Hadjidemetriou, Elena Monti, Alessia David, Karoliina Wehkalampi, Roberto Oleari, Antonella Lettieri, Valeria Vezzoli, Gilbert Vassart, Anna Cariboni, Marco Bonomi, Marie Isabelle Garcia, Leonardo Guasti, Leo Dunkel
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