Perinatal Stage Research Articles

Longitudinal developmental analysis of prethalamic eminence derivatives in the chick by mapping of Tbr1 in situ expression.

The prethalamic eminence (PThE) is the most dorsal subdomain of the prethalamus, which corresponds to prosomere 3 (p3) in the prosomeric model for vertebrate forebrain development. In mammalian and avian embryos, the PThE can be delimited from other prethalamic areas by its lack of Dlx gene expression, as well as by its expression of glutamatergic-related genes such as Pax6, Tbr2 and Tbr1. Several studies in mouse embryos postulate the PThE as a source of migratory neurons that populate given telencephalic centers. Concerning the avian PThE, it is visible at early embryonic stages as a compact primordium, but its morphology becomes cryptic at perinatal stages, so that its developmental course and fate are largely unknown. In this report, we characterize in detail the ontogeny of the chicken PThE from 5 to 15days of development, according to morphological criteria, and using Tbr1 as a molecular marker for this structure and its migratory cells. We show that initially the PThE contacts rostrally the medial pallium, the pallial amygdala and the paraventricular hypothalamic alar domain. Approximately from embryonic day 6onwards, the PThE becomes progressively reduced in size and cell content due to massive tangential migration of many of its neuronal derivatives towards nearby subpallial and hypothalamic regions. Our analysis supports that these migratory neurons from the avian PThE target telencephalic centers such as the commissural septal nuclei, as previously described in mammals, but also the diagonal band and preoptic areas, and hypothalamic structures inthe paraventricular hypothalamic area.

Importance of choline in cognitive function

Choline is a critical nutrient for cognitive development, metabolism and liver function, and regulation of homocysteine metabolism. It is necessary for the synthesis of the neurotransmitter acetylcholine, the synthesis of betaine and that of phosphatidylcholine. In the perinatal stage, the contribution of choline is essential to guarantee optimal cognitive development and prevent neural tube defects. In adults and the elderly, choline intake has been associated with better performance in some cognitive functions and a lower incidence of dementia. Despite their important role in health, most groups of the population do not reach their adequate intake of choline, and even some groups, such as pregnant women or childbearing women, have a higher risk of having suboptimal intakes. The main dietary sources of choline are eggs, dairy and meats, so reducing or limiting the consumption of these foods negatively impacts on the intake of this nutrient. Given the need to improve the intake of this vitamin, it is necessary to increase the knowledge that the population has about this nutrient, raising awareness about the importance of choline for health, and its main food sources.

Vasoactive Intestinal Peptide Derived From Liver Mesenchymal Cells Mediates Tight Junction Assembly in Mouse Intrahepatic Bile Ducts.

Formation of intrahepatic bile ducts (IHBDs) proceeds in accordance with their microenvironment. Particularly, mesenchymal cells around portal veins regulate the differentiation and ductular morphogenesis of cholangiocytes in the developing liver; however, further studies are needed to fully understand the arrangement of IHBDs into a continuous hierarchical network. This study aims to clarify the interaction between biliary and liver mesenchymal cells during IHBD formation. To identify candidate factors contributing to this cell–cell interaction, mesenchymal cells were isolated from embryonic day 16.5 matrix metalloproteinase 14 (MMP14)‐deficient (knockout [KO]) mice livers, in which IHBD formation is retarded, and compared with those of the wild type (WT). WT mesenchymal cells significantly facilitated the formation of luminal structures comprised of hepatoblast‐derived cholangiocytes (cholangiocytic cysts), whereas MMP14‐KO mesenchymal cells failed to promote cyst formation. Comprehensive analysis revealed that expression of vasoactive intestinal peptide (VIP) was significantly suppressed in MMP14‐KO mesenchymal cells. VIP and VIP receptor 1 (VIPR1) were mainly expressed in periportal mesenchymal cells and cholangiocytic progenitors during IHBD development, respectively, in vivo. VIP/VIPR1 signaling significantly encouraged cholangiocytic cyst formation and up‐regulated tight junction protein 1, cystic fibrosis transmembrane conductance regulator, and aquaporin 1, in vitro. VIP antagonist significantly suppressed the tight junction assembly and the up‐regulation of ion/water transporters during IHBD development in vivo. In a cholestatic injury model of adult mice, exogenous VIP administration promoted the restoration of damaged tight junctions in bile ducts and improved hyperbilirubinemia. Conclusion: VIP is produced by periportal mesenchymal cells during the perinatal stage. It supports bile duct development by establishing tight junctions and up‐regulating ion/water transporters in cholangiocytes. VIP contributes to prompt recovery from cholestatic damage through the establishment of tight junctions in the bile ducts.

Retinal differentiation in an altricial bird species, Taeniopygia guttata: An immunohistochemical study

The bird retina offers an excellent model to investigate the mechanisms that coordinate the morphogenesis, histogenesis, and differentiation of neuron and glial cells. Although these developmental features have been intensively studied in the chicken (Gallus gallus, Linnaeus 1758), a precocial bird species, little is known about retinogenesis in altricial birds. The purpose of this study was to examine the differentiation of retinal cells in the altricial zebra finch (Taeniopygia guttata, Vieillot, 1817) and compare the results with those from previous studies in G. gallus. By using immunohistochemical techniques, the first differentiated TUJ1-/Isl1-positive neuroblasts were detected in the vitreal surface of the neuroblastic layer at later incubation times in T. guttata than in G. gallus (108 h vs 55 h). The immunoreactivity of these early differentiation markers coincided temporo-spatially with the appearance of the first PCNA-negative nuclei. Furthermore, the first visinin-positive photoreceptors (132 h vs 120 h) and the first Prox-1-immunoreactive neuroblasts (embryonic day 7.25 (E7.25) vs E6.5) were also detected at later embryonic stages in the retina of T. guttata than in the retina of G. gallus. At E13, one day before hatching, abundant PCNA- and pHisH3-immunoreactivities were detected in the T. guttata retina, while proliferation was almost absent in the G. gallus retina at perinatal stages. Therefore, these results suggest that cell differentiation in the retina is delayed in the altricial bird compared to precocial birds. Furthermore, the T. guttata retina was not completely developed at hatching, and abundant mitotically active precursor cells of retinal neurons were found, suggesting that retinal neurogenesis was intense at perinatal stages.

Early skeletal muscle pathology and disease progress in the dy3K/dy3K mouse model of congenital muscular dystrophy with laminin \u03b12 chain-deficiency

Deficiency of laminin α2 chain leads to a severe form of congenital muscular dystrophy (LAMA2-CMD), and dystrophic symptoms progress rapidly in early childhood. Currently, there is no treatment for this detrimental disorder. Development of therapies is largely hindered by lack of understanding of mechanisms involved in the disease initiation and progress, both in patients but also in mouse models that are commonly used in the preclinical setup. Here, we unveil the first pathogenic events and characterise the disease development in a mouse model for LAMA2-CMD (dy3K/dy3K), by analysing muscles at perinatal, neonatal and postnatal stages. We found that apoptotic muscle fibres were present as early as postnatal day 1. Other typical dystrophic hallmarks (muscle degeneration, inflammation, and extensive production of the extracellular matrix proteins) were clearly evident already at postnatal day 4, and the highest degree of muscle deterioration was reached by day 7. Interestingly, the severe phenotype of limb muscles partially recovered on days 14 and 21, despite worsening of the general condition of the dy3K/dy3K mouse by that age. We found that masticatory muscles were severely affected in dy3K/dy3K mice and this may be an underlying cause of their malnutrition, which contributes to death around day 21. We also showed that several signalling pathways were affected already in 1-day-old dy3K/dy3K muscle. Therapeutic tests in the dy3K/dy3K mouse model should therefore be initiated shortly after birth, but should also take into account timing and correlation between regenerative and pathogenic events.

Maternal Protein Restriction Modulates Angiogenesis and AQP9 Expression Leading to a Delay in Postnatal Epididymal Development in Rat.

The maternal nutritional status is essential to the health and well-being of the fetus. Maternal protein restriction during the perinatal stage causes sperm alterations in the offspring that are associated with epididymal dysfunctions. Vascular endothelial growth factor (VEGF) and its receptor, VEGFr-2, as well as aquaporins (AQPs) are important regulators of angiogenesis and the epididymal microenvironment and are associated with male fertility. We investigated the effects of maternal protein restriction on epididymal angiogenesis and AQP expression in the early stages of postnatal epididymal development. Pregnant rats were divided into two experimental groups that received either a normoprotein (17% protein) or low-protein diet (6% protein) during gestation and lactation. At postnatal day (PND)7 and PND14, male offspring were euthanized, the epididymides were subjected to morphometric and microvascular density analyses and to VEGF-A, VEGF-r2, AQP1 and AQP9 expression analyses. The maternal low-protein diet decreased AQP9 and VEGFr-2 expression, decreased epididymal microvascularity and altered the morphometric features of the epididymal epithelium; no changes in AQP1 expression were observed at the beginning of postnatal epididymal development. Maternal protein restriction alters microvascularization and affects molecules involved in the epidydimal microenvironment, resulting in morphometric alterations related to a delay in the beginning of epididymis postnatal development.

Prepubertal ovarian inhibition of Light/Dark Box exploration and novel object investigation in juvenile Siberian hamsters

The overwhelming majority of research on the role of gonadal hormones in behavioral development has focused on perinatal, pubertal, or adult life stages. The juvenile period has been overlooked because it is thought to be a time of gonadal quiescence. In the present study, we tested whether prepubertal gonadectomy impacts the behavior of male and female juvenile hamsters on the Light/Dark Box, Novel Object, and Social Approach tests (Experiment 1) and compared these findings to those obtained after adult gonadectomy (Experiment 2). Prepubertal ovariectomy increased exploration (i.e. time spent in the light zone of the Light/Dark Box) and novel object investigation of juveniles indicating an inhibitory role for the juvenile ovary; social approach was unaffected. In contrast, adult ovariectomy and castration (both prepubertal and adult) had no effect on any behavioral measure. Experiment 3 tested whether rearing hamsters in a short day length (SD), which delays puberty in this species, extends the interval of juvenile ovarian inhibition on exploration and novelty seeking. We also tested whether provision of estradiol reverses the effects of prepubertal ovariectomy. Hormonal manipulations and behavioral tests of Experiment 3 were conducted at ages when long day-reared hamsters are adult (as in Experiment 2), but SD-reared hamsters remain reproductively immature. Ovariectomy again increased exploration in the SD-reared juveniles despite the older age of surgery and testing. Estradiol treatment had no effect. These findings reveal a novel role for the juvenile ovary in exploration and novelty seeking that is unlikely to be mediated exclusively by estradiol.

The role of Bmal1 in neuronal radial migration and axonal projection of the embryonic mouse cerebral cortex

Normal development of the cerebral cortex is a basis for the formation and function of mammalian brains. During this process, the radial migration of cortical neurons, as well as the axon projection into specific layers, are the most important steps regulated by some transcription factors, but the underlying molecular mechanisms are still obscure. BMAL1 (brain and muscle Arnt-like protein 1) is a newly identified transcription factor that plays important roles in the circadian rhythms. It was recently found to regulate the proliferation of hippocampal neuronal progenitor/precursor cells (NPCs), implicating Bmal1 in the brain development. Here we employed both RT-RCR and real-time PCR to explore the expression pattern of the Bmal1 gene in the developing brain. We found BMAl1 is enriched in the brain cortex during the perinatal stages and peaked in P3 mouse brains. Combined with in utero electroporation and interference with RNAi, we found that reducing the expression level of Bmal1 in neurons, the radial migration of embryonic cortical neurons was largely delayed, in a gene dose-effect pattern. Moreover, reducing the level of Bmal1 expression in mouse brains, the axonal projection in the corpus callosum was also disrupted from ipsilateral to the lateral cerebral hemisphere. These findings indicate that BMAL1 is essential for the radial migration of neurons in the cerebral cortex and the axonal projection of the corpus callosum, providing insights into the molecular mechanisms of cerebral cortex development.

Stk40 deletion elevates c-JUN protein level and impairs mesoderm differentiation

Mesoderm development is a finely tuned process initiated by the differentiation of pluripotent epiblast cells. Serine/threonine kinase 40 (STK40) controls the development of several mesoderm-derived cell types, its overexpression induces differentiation of mouse embryonic stem cells (mESCs) toward the extraembryonic endoderm, and Stk40 knockout (KO) results in multiple organ failure and is lethal at the perinatal stage in mice. However, molecular mechanisms underlying the physiological functions of STK40 in mesoderm differentiation remain elusive. Here, we report that Stk40 ablation impairs mesoderm differentiation both in vitro and in vivo Mechanistically, STK40 interacts with both the E3 ubiquitin ligase mammalian constitutive photomorphogenesis protein 1 (COP1) and the transcriptional regulator proto-oncogene c-Jun (c-JUN), promoting c-JUN protein degradation. Consequently, Stk40 knockout leads to c-JUN protein accumulation, which, in turn, apparently suppresses WNT signaling activity and impairs the mesoderm differentiation process. Overall, this study reveals that STK40, together with COP1, represents a previously unknown regulatory axis that modulates the c-JUN protein level within an appropriate range during mesoderm differentiation from mESCs. Our findings provide critical insights into the molecular mechanisms regulating the c-JUN protein level and may have potential implications for managing cellular disorders arising from c-JUN dysfunction.

PB2223 INTERFERON THERAPY FOR PREGNANT PATIENTS WITH MYELOPROLIFERATIVE NEOPLASMS IN JAPAN

Background:Philadelphia chromosome (Ph)‐negative myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis, are clonal hematopoietic disorders characterized by the overproduction of terminally differentiated hematopoietic cells. Although PV and ET have a favorable prognosis, the incidence of thromboembolic and hemorrhagic complications is high. Thus, the goal of the current treatment strategy for patients with PV and ET is to prevent these events. MPNs mainly occur in the elderly, but can also occur in younger patients, including childbearing‐aged women. For ET in particular, there is a second peak in female patients in their thirties. In addition, the risk of miscarriage and other complications in pregnant MPN patients is higher than that in the general population; therefore, the management of MPNs during pregnancy is often discussed. The European LeukemiaNet and British Committee for Standards in Haematology have suggested interferon (IFN) therapy for MPN patients during high‐risk pregnancy. However, there are currently no guidelines in Japan.Aims:To evaluate the efficacy and safety of IFN therapy for pregnant patients with MPNs in Japan.Methods:We retrospectively analyzed eight patients with MPNs who were treated using IFN‐alpha during pregnancy at our institute. This study was approved by the ethics review board of Juntendo University Hospital.Results:One patient with PV and seven patients with ET were included. Among the ET patients, three patients harbored the JAK2 V617F mutation, whereas three patients harbored the CALR type 1 or 2 mutation. The other patient was defined as having triple‐negative ET. All ET patients had JAK2 V617F mutation, history of miscarriage, or history of platelet counts higher than 1,500 x 109/L, which is why we considered their pregnancies to be high‐risk. The dose of IFN‐alpha was from 9 million units to 21 million units per week, and the median value was 9 million units per week. Two patients started IFN before pregnancy to prepare for pregnancy, whereas six patients were treated after confirming pregnancy. All patients received low‐dose aspirin and low‐molecular‐weight heparin or heparin in the perinatal stage. The most frequent adverse event of IFN was fever, but it occurred only for the first few days. All patients continued IFN therapy until delivery. The median platelet count of the seven ET patients was 1,129 x 109/L before IFN therapy, which decreased to 336 x 109/L at the time of delivery. The hematocrit level of the patient with PV decreased from 47.0% to 40.9%, and the JAK2 V617F allele burden decreased from 87.2% to 75.4%. Two babies were born at a low birth weight, however, all of the babies’ Apgar scores were in the normal range. Neither hemorrhagic nor thromboembolic complications were reported. Significant placental infarcts were found in only one patient.Summary/Conclusion:This study represents the largest single center examination of IFN treatment for MPN patients during pregnancy in Japan, and suggests the safety and efficacy of IFN therapy for pregnant patients with MPNs. Although evidence for treatment is limited and the use of IFN for Ph‐negative MPNs is not approved in Japan, we suggest considering IFN therapy for pregnant patients with MPNs.

MORPHOLOGICAL AND DEVELOPMENTAL STUDY OF HUMAN FETAL THYMUS GLAND IN KUMAON REGION

Introduction: A cross sectional study was conducted to observe morphological and developmental changes occurring in thymus gland at various gestational age among human fetuses. The morphometric measurements of thymus is useful in calculating size as intrauterine growth retardation (IUGR) and cellular immune deficiency of infant is associated with a significant decrease in fetal thymic size. Materials & Methods: This study was carried on medically aborted and stillborn fetuses (n=31; F=21, M=10), which were obtained from Dr. Sushila Tiwari Memorial Hospital, Haldwani, (Uttarakhand,) with due consent of parents. Fetuses were preserved in 10% formalin. Thymic gland was dissected out to observe its weight, length and thickness. Results: Thymus glands were located in superior mediastinum. On gross examination, they were of greyish pink to greyish brown in colour. Most of the glands were bilobed and few were irregular in shape. There was progressive increase in all morphometric dimensions of thymus in relation to gestational age. Growth of right lobe of thymus was comparatively more than of left lobe. Conclusion: Thymic morphometric parameters in relation to gestational age can be used as reference values in imaging studies in the prenatal and in initial perinatal stages, so we could compare the normal morphology with that of in IUGR and immune deficiency.

Association between perinatal depressive symptoms and suicidal risk among low-income South African women: a longitudinal study.

The aim of this study was to assess the association between depressive symptoms and suicidal risk over time among perinatal women at risk for depression antenatally, and assess modifying effects of age, perinatal stage and depressive symptom trajectory. A total of 384 adult pregnant women were recruited from two antenatal clinics in an informal settlement near Cape Town, South Africa, and followed up at eight months gestation, and at 3- and 12-month postpartum. The MINI 6.0 Suicidality module and the Hamilton Depression Rating Scale (HDRS) were used to measure suicidal risk and depression, respectively. Generalised Estimating Equations were used to assess the association between change in depressive symptoms from one assessment to the next (predictor) and change in suicide score or change in suicidal risk (score ≥ 9) (outcomes). HDRS scores were positively correlated with suicide score (95% CI 0.35, 0.78; p < 0.001), and with odds of being at moderate risk for suicide, after controlling for risk of suicide at the previous assessment (adjusted odds ratio = 1.15; 95% CI 1.09, 1.22; p < 0.001). Age was a significant effect modifier: change in HDRS scores was not associated with change in suicide scores among participants aged 35-45years. Secondary analyses indicated that a decrease in HDRS score was associated with a decrease in suicide scores, but an increase in HDRS score was not associated with change in suicide score. Depression and suicide are overlapping but relatively independent phenomena, especially among older or more chronically depressed perinatal women.

Npat-dependent programmed Sertoli cell proliferation is indispensable for testis cord development and germ cell mitotic arrest.

As the major somatic cell type, Sertoli cells undergo active proliferation and play essential roles to establish testis cord at fetal stage. They also function to maintain germ cell development throughout the life of testicular development. However, the significance of Sertoli cell number for testis cord development and gonocyte fate is still unclear. Nuclear protein ataxia-telangiectasia (NPAT, also known as p220), a substrate of cyclin E/cyclin-dependent kinase 2, is well known as a regulator of cell proliferation through regulating histone expression. To study the role of NPAT during Sertoli cell development, we generated a mouse strain carrying conditional floxed Npat alleles, when crossing with anti-Müllerian hormone-cre, leading to the specific deletion of Npat in Sertoli cells. Npat disruption in Sertoli cells inhibited the programmed proliferation of fetal Sertoli cells resulting in disruption of developing testis cords, and subsequent postnatal mutant testes were severely hypoplastic. Germ cells, which are presumed to be in quiescent status during perinatal stage, exited G0 phase arrest and re-enter mitotic cell cycle prematurely. Of particular note, some germ cells possessed the meiotic signal in Npat-deficient testes. Our data thus indicates that the function of Npat-dependent Sertoli cells is essential at multiple steps in testis development, and this study also identifies Sertoli cells as a major regulator of germ cell development, which are required to maintain a local growth niche to repress premature mitosis and meiosis of gonocytes.-Jiang, X., Yin, S., Fan, S., Bao, J., Jiao, Y., Ali, A., Iqbal, F., Xu, J., Zhang, Y., Shi, Q. Npat-dependent programmed Sertoli cell proliferation is indispensable for testis cord development and germ cell mitotic arrest.

Clinical diagnosis and treatment of perinatal stage hemophagocytic lymphohistiocytosis

目的分析围产期相关噬血细胞综合征（hemophagocytic lymphohistiocytosis，HLH）的临床特征。方法对2011年1月至2016年10月诊治的11例围产期HLH患者基本信息、临床特点、相关疾病/因素和治疗效果进行观察。结果11例HLH患者中，初产妇9例。妊娠期发病5例，产后发病6例。6例患者存在相关疾病/因素，感染最为常见（6例）。治疗方案包括糖皮质激素+氟达拉滨1例，HLH-94/04方案9例，单药激素1例。最终2例患者死亡。结论围产期（妊娠28周至产后7 d）HLH在妊娠/产后相关HLH噬血中很常见。感染是最常见的相关因素。终止妊娠后进行治疗是有效的，而仅仅终止妊娠可能还不足以控制围产期相关HLH。围产期相关HLH的转归优于其他继发性HLH亚型。

SAT-410 Kisspeptin Is Required for Perinatal Testosterone Surge in Male Rats

Perinatal testosterone surge derived from testes is critical for masculinization and defeminization of the brain in male rats. Kisspeptin is indispensable for activation of hypothalamus-pituitary-gonadal (HPG) axis to induce testicular testosterone secretion in adult male rats, yet it is unclear if perinatal kisspeptin is responsible for perinatal testosterone surge in male rats. We previously reported that kisspeptin gene knockout (Kiss1-KO) male rats showed high score of lordosis quotient, indicating that kisspeptin is required for defeminization of the brain controlling sexual behaviors. Hence, the present study aimed to investigate the role of kisspeptin in inducing perinatal testosterone surge. First, we examined plasma testosterone and luteinizing hormone (LH) levels at several timepoints during perinatal stage in Kiss1-KO and wild-type (WT) male rats to determine the perinatal testosterone surge and LH elevation. In WT rats, plasma testosterone significantly increased at 0-1.5 and 1.5-3 hours after birth than in embryonic day 21 (E21). Plasma LH also increased significantly at birth (0 hour after birth) than in E21. In contrast, either plasma testosterone or LH was kept at low levels during perinatal period in Kiss1-KO rats. To determine whether external kisspeptin can induce testosterone surge in Kiss1-KO rats, we injected kisspeptin to neonatal males within 2 hours after birth and collected blood samples or brains 1 hour later. After the kisspeptin injection, both plasma testosterone and LH levels were significantly increased in Kiss1-KO rats. Double immunostaining with GnRH and c-Fos revealed that the rate of GnRH neurons expressing c-Fos was significantly higher in Kiss1-KO rats treated with kisspeptin (20.59±4.17%) compared to vehicle-treated Kiss1-KO rats (1.47±1.08%). Taken together, these results suggest that testosterone surge occurring in perinatal male rats, which cause the defeminization of the brain, is kisspeptin dependent and initiation of the testosterone surge is likely to be mediated by kisspeptin-induced activation of HPG axis.

Investigating the Origins of Congenital Heart Defects in a Mouse Model of Cornelia de Lange Syndrome

Congenital heart defects (CHDs) are among the most common birth defects and are a major cause of infant mortality. Increasing evidence suggests that CHDs result from the combinatorial effects of variations in the expression of multiple genes throughout the genome. As one approach to understand the multifactorial origins of CHDs, we have generated and studied mouse models of Cornelia de Lange Syndrome (CdLS), a multisystem birth defects disorder that arises in most instances from haplinsufficiency for NIPBL. The NIPBL gene encodes a cohesin binding factor that is also known to have global effects on gene expression, and Nipbl‐deficient vertebrate animal models of CdLS, such as Nipbl‐deficient mice and zebrafish, recapitulate both the large array of structural birth defects observed in CdLS and the global dysregulation of gene expression observed in cells from individuals with CdLS (e.g., Kawauchi et al., 2009, PLoS Genetics; Muto et al., 2011, PLoS Biology). Strikingly, Nipbl+/− mice exhibit CHD at a frequency of ~30%, similar to the level observed in individuals with CdLS. This high degree of penetrance makes such mice an excellent model system for understanding the complex origins of CHDs.In a recent study, we generated an allelic series of Nipbl in the mouse, which allows us to selectively create or rescue Nipbl haploinsufficiency in different tissues (Santos et al., 2016, PLoS Biology). We used this allelic series to understand the tissue origins of CHD in CdLS, and found that defects were apparent from the earliest times of heart development. Specifically, we found deficits in the numbers of developing cardiac progenitor cells; defects in right ventricle development during early heart development; defects in ventricular septation during mid‐gestation; and a high incidence (~30%) of atrial septal defects (ASDs) at perinatal stages of heart development (ibid). The results of these and other studies (Chea, Calof, unpublished observations) suggested that, in CdLS, the origins of CHD lie at the earliest stages of heart development, during the initial allocation of cardiac progenitors to the first and second heart fields (FHF, SHF). Because the SHF contributes cells that make up the bulk of the right ventricle, and defects in the SHF can lead to defects in outflow tract and atrial septum development, we are particularly interested in whether Nipbl deficiency in the SHF specifically may be responsible for the CHD observed in CdLS. To test this, we are crossing mice carrying SHF‐specific Cre recombinases with NipblFlox mice, in order to generate offspring with Nipbl haploinsufficiency specifically in the SHF and its derivatives. Results from these studies will allow us to determine whether Nipbl deficiency in the SHF and its derivatives is necessary and sufficient for the development of the high incidence of CHD in CdLS.Support or Funding InformationSupported by a grant to ALC and ADL from the National Institute of Heart, Lung, and Blood Disorders (HL138659‐02) of the NIH.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Ectopic expression of DNA methyltransferases DNMT3A2 and DNMT3L leads to aberrant hypermethylation and postnatal lethality in mice.

DNA methylation is generally known to inactivate gene expression. The DNA methyltransferases (DNMTs), DNMT3A and DNMT3B, catalyze somatic cell lineage‐specific DNA methylation, while DNMT3A and DNMT3L catalyze germ cell lineage‐specific DNA methylation. How such lineage‐ and gene‐specific DNA methylation patterns are created remains to be elucidated. To better understand the regulatory mechanisms underlying DNA methylation, we generated transgenic mice that constitutively expressed DNMT3A and DNMT3L, and analyzed DNA methylation, gene expression, and their subsequent impact on ontogeny. All transgenic mice were born normally but died within 20 weeks accompanied with cardiac hypertrophy. Several genes were repressed in the hearts of transgenic mice compared with those in wild‐type mice. CpG islands of these downregulated genes were highly methylated in the transgenic mice. This abnormal methylation occurred in the perinatal stage. Conversely, monoallelic DNA methylation at imprinted loci was faithfully maintained in all transgenic mice, except H19. Thus, the loci preferred by DNMT3A and DNMT3L differ between somatic and germ cell lineages.

Long Term Perinatal Deltamethrin Exposure Alters Electrophysiological Properties of Embryonic Ventricular Cardiomyocyte.

Increased use of pyrethroids and the exposure to pyrethroids for pregnant women and children have raised the concerns over the potential effect of pyrethroids on developmental cardiotoxicity and other abnormalities. The purpose of this study was to investigate whether long term perinatal deltamethrin exposure altered embryonic cardiac electrophysiology in mice. Pregnant mice were administered with 0 or 3 mg/kg of deltamethrin by gavage daily from gestational day (gd) 10.5 to gd 17. 5. Whole cell patch-clamp technique was used in electrophysiological study, and real time RT-PCR was applied to analyze the molecular changes for the electrophysiological properties. Deltamethrin exposure resulted in increased mortality of pregnant mice and decreased viability of embryos. Moreover, deltamethrin slowed the maximum depolarization velocity (Vmax), prolonged the action potential duration (APD) and depolarized the maximum diastolic potential (MDP) of embryonic cardiomyocytes. Additionally, perinatal deltamethrin exposure decreased the mRNA expression of Na+ channel regulatory subunit Navβ1, inward rectifier K+ channel subunit Kir2.1, and delayed rectifier K+ channel subunit MERG while the L-type Ca2+ channel subunit, Cav1.2 expression was increased. On the contrary, deltamethrin administration did not significantly alter the regulation of β-adrenergic or muscarinic receptor on embryonic cardiomyocytes. In conclusion, deltamethrin exposure at perinatal stage significantly alters mRNA expression of embryonic cardiac ion channels and therefore influences embryonic cardiac electrophysiological properties. This highlights the need to understand the persistent effects of pyrethroid exposure on cardiac function during embryonic development due to potential for cardiac arrhythmogenicity.

Early Programming during Attachment Development and its Relevance for Risk/Resilience of Neuropsychiatric and Cardiometabolic Diseases during Adulthood

Social and cultural environmental factors influence the development of susceptibility to diseases in adulthood since the peri-natal stages of life. Sociotype describes the way in which interactions between social, cultural and environmental factors influence health. It plays a role as important as that of the genotype and phenotype in the balance of the health/disease processes during all the life span. Attachment forms part of the sociotype and is defined as the innate biological system that characterizes the link between an infant and a bonding figure. It increases the possibility of survival to a reproductive age and determines empathy and intimacy that when incorrectly established may be the cause of a number of pathological conditions in the adult life. Different types of attachment have, as a consequence, physiological and endocrinological alterations that result from the exposure to stressful and/or traumatic events during early stages of life. These constitute long- term plastic changes in structures in the central nervous system that produce in alterations in signaling molecule production that may arise from epigenetic cues established during the early stages of life in trauma- exposed subjects and that may lead to increased risk of diseases in adulthood. Therefore, sociotype and attachment might determine epigenetic alterations that may act on biological pathways involved in the comorbidity of cardiometabolic and neuropsychiatric diseases.

The Superior Function of the Subplate in Early Neocortical Development.

During early development the structure and function of the cerebral cortex is critically organized by subplate neurons (SPNs), a mostly transient population of glutamatergic and GABAergic neurons located below the cortical plate. At the molecular and morphological level SPNs represent a rather diverse population of cells expressing a variety of genetic markers and revealing different axonal-dendritic morphologies. Electrophysiologically SPNs are characterized by their rather mature intrinsic membrane properties and firing patterns. They are connected via electrical and chemical synapses to local and remote neurons, e.g., thalamic relay neurons forming the first thalamocortical input to the cerebral cortex. Therefore SPNs are robustly activated at pre- and perinatal stages by the sensory periphery. Although SPNs play pivotal roles in early neocortical activity, development and plasticity, they mostly disappear by programmed cell death during further maturation. On the one hand, SPNs may be selectively vulnerable to hypoxia-ischemia contributing to brain damage, on the other hand there is some evidence that enhanced survival rates or alterations in SPN distribution may contribute to the etiology of neurological or psychiatric disorders. This review aims to give a comprehensive and up-to-date overview on the many functions of SPNs during early physiological and pathophysiological development of the cerebral cortex.