Macrophages are commonly thought to contribute to the pathophysiology of preterm labor by amplifying inflammation — but a protective role has not previously been considered to our knowledge. We hypothesized that given their antiinflammatory capability in early pregnancy, macrophages exert essential roles in maintenance of late gestation and that insufficient macrophages may predispose individuals to spontaneous preterm labor and adverse neonatal outcomes. Here, we showed that women with spontaneous preterm birth had reduced CD209+CD206+ expression in alternatively activated CD45+CD14+ICAM3– macrophages and increased TNF expression in proinflammatory CD45+CD14+CD80+HLA-DR+ macrophages in the uterine decidua at the materno-fetal interface. In Cd11bDTR/DTR mice, depletion of maternal CD11b+ myeloid cells caused preterm birth, neonatal death, and postnatal growth impairment, accompanied by uterine cytokine and leukocyte changes indicative of a proinflammatory response, while adoptive transfer of WT macrophages prevented preterm birth and partially rescued neonatal loss. In a model of intra-amniotic inflammation–induced preterm birth, macrophages polarized in vitro to an M2 phenotype showed superior capacity over nonpolarized macrophages to reduce uterine and fetal inflammation, prevent preterm birth, and improve neonatal survival. We conclude that macrophages exert a critical homeostatic regulatory role in late gestation and are implicated as a determinant of susceptibility to spontaneous preterm birth and fetal inflammatory injury.
Nardhy Gomez-Lopez, Valeria Garcia-Flores, Peck Yin Chin, Holly M. Groome, Melanie T. Bijland, Kerrilyn R. Diener, Roberto Romero, Sarah A. Robertson
Retinoic Acid (RA) signaling has long been speculated to regulate embryo implantation, because many enzymes and proteins responsible for maintaining RA homeostasis and transducing RA signals are tightly regulated in the endometrium during this critical period. However, due to lack of genetic data, it was unclear whether RA signaling is truly required for implantation, and which specific RA signaling cascades are at play. Herein we utilize a genetic murine model that expresses a dominant negative form of RA receptor specifically in female reproductive organs to show that functional RA signaling is fundamental to female fertility, particularly implantation and decidualization. Reduction in RA signaling activity severely affects the ability of the uterus to achieve receptive status and decidualize, partially through dampening follistatin expression and downstream activin B/BMP2 signaling. To confirm translational relevance of these findings to humans, human endometrial stromal cells (hESCs) were treated with pan-RAR antagonist to show that in vitro decidualization is impaired. RNAi perturbation of individual RAR transcripts in hESCs revealed that RARα in particular is essential for proper decidualization. These data provide direct functional evidence that uterine RAR-mediated RA signaling is crucial for mammalian embryo implantation, and its disruption leads to failure of uterine receptivity and decidualization resulting in severely compromised fertility.
Yan Yin, Meade E. Haller, Sangappa B. Chadchan, Ramakrishna Kommagani, Liang Ma
The syndrome of spontaneous preterm birth (sPTB) presents a challenge to mechanistic understanding, effective risk stratification, and management. Individual associations between sPTB, ethnicity, vaginal microbiota, metabolome and innate immune response are known, but not fully understood and knowledge has yet to impact clinical practice. Here we use multi-data type integration and composite statistical models to gain insight into sPTB risk by exploring the cervicovaginal environment of an ethnically heterogenous pregnant population (n=346 women; n=60 sPTB <37 weeks’ gestation, including n=27 sPTB <34 weeks). Analysis of cervicovaginal samples (10-15+6 weeks) identified novel interactions between risk of sPTB and microbiota, metabolite, and maternal host defense molecules. Statistical modelling identified a composite of metabolites (leucine, tyrosine, aspartate, lactate, betaine, acetate and Ca2+) associated with risk of sPTB <37 weeks (Area Under the Curve - AUC 0.752). A combination of glucose, aspartate, Ca2+ and Lactobacillus crispatus and L. acidophilus relative abundance, identified risk of early sPTB <34 weeks, (AUC 0.758); improved by ethnicity stratification (AUC 0.835). Increased relative abundance of L. acidophilus appeared protective against sPTB <34 weeks. By using cervicovaginal fluid samples, we demonstrate the potential of multi-datatype integration for developing composite models towards understanding the contribution of the vaginal environment to risk of sPTB.
Flavia Flaviani, Natasha L. Hezelgrave, Tokuwa Kanno, Erica M. Prosdocimi, Evonne Chin-Smith, Alexandra E. Ridout, Djuna K. von Maydell, Vikash Mistry, William G. Wade, Andrew H. Shennan, Konstantina Dimitrakopoulou, Paul T. Seed, Andrew James Mason, Rachel M. Tribe
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.
Melissa L. Erickson, Zachary W. Patinkin, Allison M. Duensing, Dana Dabelea, Leanne M. Redman, Kristen E. Boyle
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.
William E. Ackerman IV, Catalin S. Buhimschi, Ali Snedden, Taryn L. Summerfield, Guomao Zhao, Irina A. Buhimschi
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.
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
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.
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
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.
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
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.
Ron Hadas, Eran Gershon, Aviad Cohen, Ofir Atrakchi, Shlomi Lazar, Ofra Golani, Bareket Dassa, Michal Elbaz, Gadi Cohen, Raya Eilam, Nava Dekel, Michal Neeman
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.
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
No posts were found with this tag.