Biology subjects

Sloboda, D. M.

Publications and source records attributed to Sloboda, D. M..

12 recordsLinked to original sources

bioRxiv2025

Obesogenic diet alters decidual differentiation and cell-cell communication in the mouse uterus

Maternal obesity is associated with increased risk of infertility, implantation failure, miscarriage, and other pregnancy complications. While prior studies have linked obesity to uterine dysfunction and impaired endometrial biology, how obesity alters the cellular and molecular landscape of the early pregnant endometrium remains poorly understood. Here, we perform single-cell RNA sequencing of embryonic day 5.5 uterus from control and obesogenic mice to generate a cellular atlas of the early decidualizing endometrium. We identify obesity-associated transcriptional changes across multiple Endometrial Stromal Cell (ESC) states and innate immune populations, including uterine natural killer cells and macrophages. Computational modeling reveals that maternal obesity disrupts distinct routes of ESC differentiation during decidualization and leads to shifts in ESC-derived cues known to impact innate immune responses. These findings provide a comprehensive single-cell resource of the post-implantation mouse endometrium while simultaneously generating critical insight into how maternal obesity reprograms the maternal-fetal interface in early pregnancy.

developmental biology↗

bioRxiv2024

Maternal high-fat, high-sucrose diet-induced excess adiposity is linked to placental hypoxia and disruption of fetoplacental immune homeostasis in late gestation

Maternal excess adiposity (i.e., overweight and obesity) at conception is linked to numerous signs of malperfusion and inflammatory injury in the placenta. Previous reports have suggested that obesity-associated placental malperfusion may trigger a state of fetoplacental hypoxia, contributing to adverse health outcomes within and beyond the perinatal period. However, many previous studies have relied on indirect measures of tissue oxygen saturation, including readouts influenced by external inflammatory stressors. Direct comparisons of tissue oxygen saturation at the uteroplacental interface in pregnancies complicated by excess adiposity are lacking. Here, we used a mouse model of chronic preconception high-fat, high-sucrose (HFHS) diet feeding to model the impacts of an obesogenic milieu on placental oxygenation near term gestation (E17.5). We found that both placental junctional and labyrinth zone tissues were relatively hypoxic in HFHS pregnancies compared to chow-fed controls (CON). However, this was not associated with enhanced HIF-1 expression in labyrinth tissues. Similarly, placentas from CON and HFHS dams did not exhibit gross differences in morphology or vessel density and pericyte coverage. However, HFHS placentas have a greater burden of histopathological lesions, including tissue calcification and fibrinoid deposition within the labyrinth zone. Calcified placental tissue coincided with the destruction of vasculosyncytial membranes and macrophage-dense foci, alongside altered expression of immunomodulatory and chemotactic cytokines within the labyrinth zone proteome, which differed in magnitude with fetal sex. While fetal growth was not markedly affected, fetuses from HFHS pregnancies exhibited higher levels of circulating IL-6, prolactin, CXCL1, and CCL2. Collectively, these data confirm that diet-induced maternal excess adiposity leads to a relative state of placental hypoxia, even in the absence of marked growth restriction or fetal demise. While this hypoxic state is not linked to gross morphological abnormalities, it is associated with a greater histopathological burden indicative of local malperfusion and inflammation, and an altered fetal inflammatory and endocrine milieu in late gestation. These findings provide new insight into mechanisms by which an obesogenic environment during pregnancy compromises placental function and contributes to the long-term programming of chronic disease susceptibility.

developmental biology↗

bioRxiv2024

Maternal obesogenic diet disrupts mid-gestation decidual immune and vascular homeostasis without impairing spiral artery remodelling

Excess maternal adiposity (i.e., overweight and obesity) during pregnancy has been linked to impaired uteroplacental perfusion, compromised placental development, and a higher risk of adverse pregnancy outcomes. Owing to the nature of chronic inflammation and immune dysregulation accompanying excess adiposity, disruption of leukocyte-mediated tissue remodelling and immunoregulation within the decidua have emerged as likely drivers contributing to suboptimal placental function in pregnancies impacted by maternal overweight or obesity. However, the impacts of excess adiposity on major populations of innate lymphoid cells (ILCs) and macrophages which orchestrate these processes and the environment that these cells occupy remain vastly understudied. Here, we used a mouse model of chronic high-fat, high-sucrose (HFHS) diet-feeding to characterize the impacts of an obesogenic milieu on decidual immune dynamics during placental development at mid-gestation (E10.5). HFHS pregnancies exhibited marked increases in total decidual leukocyte abundance, driven by population-level increases in tissue-resident and conventional NK cells, and MHC-II+ macrophages. This was not associated with abnormalities in implantation site morphology or decidual spiral artery remodelling but was coincident with histological patterns of local inflammation. In line with this, expression of canonical proinflammatory cytokines and chemokines were moderately upregulated in bulk decidual tissue of HFHS dams. This was accompanied by more potent elevations in multiple mediators of angiogenesis, endothelial activation, and coagulation in HFHS decidual tissue. Collectively, these findings point towards pathological vascular inflammation and possibly dysregulated decidual angiogenesis in the first half of pregnancy as factors predisposing to reduced placental efficiency, malperfusion, and inflammation seen in pregnancies affected by maternal overweight and obesity.

developmental biology↗

bioRxiv2023

Maternal adaptations in mouse lactation are vulnerable to diet-induced excess adiposity

Lifetime maternal risk of obesity is increased by excess gestational weight gain, which alters maternal metabolic adaptations in pregnancy, but the effects of excess weight retention/adiposity in the early postpartum period have not been extensively studied. The pathophysiology of excess adiposity and its accompanying immunometabolic dysregulation are associated with impaired intestinal barrier function in both non-pregnant and pregnant contexts. Using a mouse model, we investigated effects of diet-induced excess adiposity on maternal physiological adaptations during lactation. We report that in lactation, excess adiposity altered maternal intestinal morphology, influenced local immune cell composition and phenotype, increased intestinal permeability, and altered whole-body glucose metabolism as well as peripheral inflammation and immune cell composition. Many of these effects persisted two months post-lactation in mice with excess adiposity. Our findings have important implications for the development of interventions for periconceptual/perinatal excess adiposity and emphasize that further studies are needed to better understand effects of excess adiposity on maternal postpartum health.

developmental biology↗

bioRxiv2022

Diet-induced obesity alters intestinal monocyte-derived and tissue-resident macrophages in female mice independent of TNF

Macrophages are essential for homeostatic maintenance of the anti-inflammatory and tolerogenic intestinal environment, yet monocyte-derived macrophages can promote local inflammation. Pro-inflammatory macrophage accumulation within the intestines may contribute to the development of systemic chronic inflammation and immunometabolic dysfunction in obesity. Using a model of high fat diet-induced obesity in C57BL/6J female mice, we assessed intestinal permeability by in vitro and in vivo assays, and quantitated intestinal macrophages in ileum and colon tissues by multicolour flow cytometry after short (6 weeks), intermediate (12 weeks), and prolonged (18 weeks) diet allocation. We characterized monocyte-derived CD4-TIM4- and CD4+TIM4- macrophages, as well as tissue-resident CD4+TIM4+ macrophages. Diet-induced obesity had tissue and time-dependent effects on intestinal permeability, as well as monocyte and macrophage numbers, surface phenotype, and intracellular production of the cytokines IL-10 and TNF. We found that obese mice had increased paracellular permeability, in particular within the ileum, but this did not elicit recruitment of monocytes, nor a local pro-inflammatory response by monocyte-derived or tissue-resident macrophages, in either the ileum or colon. Proliferation of monocyte-derived and tissue-resident macrophages was also unchanged. Wildtype and TNF-/- littermate mice had similar intestinal permeability and macrophage population characteristics in response to diet-induced obesity. These data are unique from reported effects of diet-induced obesity on macrophages in metabolic tissues, as well as outcomes of acute inflammation within the intestines, and collectively indicate that TNF does not mediate effects of diet-induced obesity on intestinal monocyte-derived and tissue-resident intestinal macrophages in young female mice. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/509732v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@140a3c8org.highwire.dtl.DTLVardef@c0d887org.highwire.dtl.DTLVardef@c7c70dorg.highwire.dtl.DTLVardef@1dd5404_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2022

Parity modulates impact of BMI and Gestational Weight Gain on gut microbiota in human pregnancy

Pregnancy requires maternal adaptations to support fetal growth: whether these adaptations include temporal shifts in the gut microbiome is still unclear. We investigated the maternal gut microbiome longitudinally over the course of pregnancy and the impact of pre-pregnancy BMI (pBMI) and GWG. We also determined whether parity modulated observed associations. We show that the gut microbiota of participants with higher pBMI changed less over the course of pregnancy in primiparous, but not multiparous participants. This suggests that previous pregnancies may have persistent impacts on maternal adaptations to pregnancy. This ecological memory appears to be passed to the next generation, as parity modulated the impact of maternal GWG on the infant gut microbiome. This work supports a role for the gut microbiome in maternal adaptations to pregnancy and highlights the need for longitudinal sampling and accounting for parity as key considerations for studies of the microbiome in pregnancy and infants.

microbiology↗

bioRxiv2022

Paternal obesity alters the sperm epigenome and is associated with changes in the placental transcriptome and cellular composition

Paternal obesity has been implicated in adult-onset metabolic disease in offspring. However, the molecular mechanisms driving these paternal effects and the developmental processes involved remain poorly understood. One underexplored possibility is the role of paternally driven gene expression in placenta function. To address this, we investigated paternal high-fat diet-induced obesity in relation to sperm epigenetic signatures, the placenta transcriptome and cellular composition. C57BL6/J males were fed either a control or high-fat diet for 10 weeks beginning at 6 weeks of age. Males were timed-mated with control-fed C57BL6/J females to generate pregnancies, followed by collection of sperm, and placentas at embryonic day (E)14.5. Chromatin immunoprecipitation targeting histone H3 lysine 4 tri-methylation (H3K4me3) followed by sequencing (ChIP-seq) was performed on sperm to define obesity-associated changes in enrichment. Paternal obesity corresponded with altered sperm H3K4me3 enrichment at imprinted genes, and at promoters of genes involved in metabolism and development. Notably, sperm altered H3K4me3 was localized at placental enhancers and genes implicated in placental development and function. Bulk RNA-sequencing on placentas detected paternal obesity-induced sex-specific changes in gene expression associated with hypoxic processes such as angiogenesis, nutrient transport and imprinted genes. Paternal obesity was also linked to placenta development; specifically, a deconvolution analysis revealed altered trophoblast cell lineage specification. These findings implicate paternal obesity-effects on placenta development and function as one mechanism underlying offspring metabolic disease. Summary sentencePaternal obesity impacts the sperm epigenome at genes implicated in placenta development and is associated with an altered placenta transcriptome and trophoblast cell lineage specification.

developmental biology↗

bioRxiv2022

Intestinal permeability and peripheral immune cell composition are altered by pregnancy and adiposity at mid- and late-gestation in the mouse

It is clear that the gastrointestinal tract influences metabolism and immune function. Most studies to date have used male test subjects, with a focus on effects of obesity and dietary challenges. Despite significant physiological adaptations that occur across gestation, relatively few studies have examined pregnancy-related gut function. In this study, we investigated the impacts of pregnancy and adiposity on maternal intestinal epithelium morphology, in vivo intestinal permeability, and peripheral blood immunophenotype, using control (CTL) and high-fat (HF) fed non-pregnant female mice and pregnant mice at mid-(embryonic day (E)14.5) and late (E18.5) gestation. We found that small intestine length increased between non-pregnant mice and dams at late-gestation, but ileum villus length, and ileum and colon crypt depths and goblet cell numbers remained similar. Compared to CTL-fed mice, HF-fed mice had reduced small intestine length, ileum crypt depth and villus length. Goblet cell numbers were only consistently reduced in HF-fed non-pregnant mice. Pregnancy increased in vivo gut permeability, with a greater effect at mid-versus late-gestation. Non-pregnant HF-fed mice had greater gut permeability, and permeability was also increased in HF-fed pregnant dams at mid but not late-gestation. The impaired maternal gut barrier in HF-fed dams at mid-gestation coincided with changes in maternal blood and bone marrow immune cell composition, including an expansion of circulating inflammatory Ly6Chigh monocytes. In summary, pregnancy has temporal effects on maternal intestinal structure and barrier function, and on peripheral immunophenotype, which are further modified by HF diet-induced maternal adiposity.

developmental biology↗

bioRxiv2021

Gut microbiota-based vaccination engages innate immunity to improve blood glucose control in obese mice

Obesity and diabetes increase circulating levels of microbial components derived from the gut microbiota. Individual bacterial factors (i.e., postbiotics) can have opposing effects on metabolic inflammation and blood glucose control. We tested the net effect of gut bacterial extracts on blood glucose using a microbiota-based vaccination strategy in mice. Male and female mice had improved insulin sensitivity and blood glucose control five weeks after a single subcutaneous injection of a specific dose of a bacterial extract obtained from the luminal contents of the proximal gut. Injection of mice with proximal gut extracts from germ-free mice revealed that bacteria were required for a microbiota-based vaccination to improve blood glucose control. Vaccination of Nod1-/-, Nod2-/-, and Ripk2-/- mice showed that each of these innate immune proteins was required for bacterial extract injection to improve blood glucose control. A microbiota-based vaccination promoted a proximal gut immunoglobulin-G (IgG) response directed against bacterial extract antigens, where subcutaneous injection of mice with the luminal contents of the ileum elicited a bacterial extract-specific IgG response that is compartmentalized to the ileum of vaccinated mice. A microbiota-based vaccination was associated with an altered the microbiota composition in the ileum and colon of mice. Lean mice required a single injection of proximal gut bacterial extracts, but high fat diet (HFD)-fed, obese mice required prime-boost bacterial extract injections for improvements in blood glucose control. These data show that, upon subversion of the gut barrier, vaccination with proximal gut bacterial extracts engages innate immunity to promote long-lasting improvements in blood glucose control in a dose-dependent manner.

physiology↗

bioRxiv2021

Paternal obesity results in placental hypoxia and sex-specific impairments in placental vascularization and offspring metabolic function

Paternal obesity predisposes offspring to metabolic dysfunction, but the underlying mechanisms remain unclear. We investigated whether paternal obesity-induced offspring metabolic dysfunction is associated with placental endoplasmic reticulum (ER) stress and impaired vascular development. We determined whether offspring glucose intolerance is fueled by ER stress-mediated changes in fetal hepatic development. Furthermore, we also determined whether paternal obesity may indirectly affect in utero development by disrupting maternal metabolic adaptations to pregnancy. Male mice fed a standard chow diet (CON; 17% kcal fat) or high fat diet (PHF; 60% kcal fat) for 8-10 weeks were time-mated with control female mice to generate pregnancies and offspring. Glucose tolerance in pregnant females was evaluated at mid-gestation (embryonic day (E) 14.5) and term gestation (E18.5). At E14.5 and E18.5, fetal liver and placentae were collected, and markers of hypoxia, angiogenesis, endocrine function, and macronutrient transport, and unfolded protein response (UPR) regulators were evaluated to assess ER stress. Young adult offspring glucose tolerance and metabolic parameters were assessed at [~]60 days of age. Paternal obesity did not alter maternal glucose tolerance or placental lactogen in pregnancy but did induce placental hypoxia, ER stress, and altered placental angiogenesis. This effect was most pronounced in placentae associated with female fetuses. Consistent with this, paternal obesity also activated the ATF6 and PERK branches of the UPR in fetal liver and altered hepatic expression of gluconeogenic factors at E18.5. Adult offspring of obese fathers showed glucose intolerance and impaired whole-body energy metabolism, particularly in female offspring. Thus, paternal obesity programs sex-specific adverse placental structural and functional adaptations and alters fetal hepatic development via ER stress-induced pathways. These changes likely underpin metabolic deficits in adult offspring. Summary SentencePaternal obesity alters placental vascular structures and is associated with sex-specific compromises in glucose tolerance and metabolism in young offspring

physiology↗

bioRxiv2021

Fetal gut colonization: meconium does not have a detectable microbiota before birth

Microbial colonization of the human intestine impacts host metabolism and immunity, however when colonization occurs is unclear. Although numerous studies have reported bacterial DNA in first-pass meconium samples, these samples are collected hours to days after birth. We investigated whether bacteria could be detected in meconium prior to birth. Fetal meconium (n = 20) was collected by rectal swab during elective breech Cesarean sections without labour prior to antibiotics and compared to technical and procedural controls (n = 5), first-pass meconium (neonatal meconium; n = 14), and infant stool (n = 25). Unlike first-pass meconium, no microbial signal distinct from negative controls was detected in fetal meconium by 16S rRNA gene sequencing. Additionally, positive aerobic (n = 10 of 20) and anaerobic (n = 12 of 20) clinical cultures of fetal meconium (13 of 20 samples positive in at least one culture) were identified as likely skin contaminants, most frequently Staphylococcus epidermidis, and not detected by sequencing in most samples (same genera detected by culture and sequencing in 2 of 13 samples with positive culture). We conclude that fetal gut colonization does not occur before birth, and that microbial profiles of neonatal meconium reflect populations acquired during and after birth.

microbiology↗

bioRxiv2018

High-fat diet intake modulates maternal intestinal adaptations to pregnancy, and results in placental hypoxia and impaired fetal gut development

Shifts in maternal intestinal microbiota have been implicated in metabolic adaptations to pregnancy. In this study we investigated how high-fat diet intake impacts the maternal gut microbiota, intestinal inflammation and gut barrier integrity, placental inflammation, and fetal intestinal development at E18.5. High-fat diet (HFD) was associated with decreased relative abundancesof SCFA producing genera during pregnancy. These diet-induced shifts paralleled decreased maternal intestinal mRNA levels of SCFA receptor Gpr41, modestly decreased cecal butyrate, and altered mRNA levels of inflammatory cytokines and immune cell markers in the maternal intestine. Maternal HFD resulted inimpaired gut barrier integrity, with corresponding increases in circulating maternal levels of LPS and TNF.Placentafromhigh-fat fed damsdemonstrated blood vessel immatu-rityand hypoxia, decreased freecarnitine, acylcarnitine derivatives, TMAO, as well as altered mRNA levels of inflammation, autophagy and ER stress markers. HFD exposed fetuses had increased activation of NF-{kappa}B and inhibition of the unfolded protein response in the developing intestine. Together, these data suggest that high-fat diet intake prior to and during pregnancy shifts the composition of the maternal gut microbiota and impairs gut barrier integrity, resulting in increased maternal circulating LPS, which may ultimate contribute to changes in placental vasculariza-tion and fetal gut development.\n\nFunding informationFarncombe Family Digestive Health Research Institute (KMK); Canadian Institute of Health Research (CJB); Canada Research Chairs Program (MGS, DMS); Natural Sciences and Engineering Research Council of Canada, Genome Canada (PBM).

developmental biology↗