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1.
J Physiol ; 602(10): 2265-2285, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38632887

RESUMO

The mechanisms governing brain vascularization during development remain poorly understood. A key regulator of developmental vascularization is delta like 4 (DLL4), a Notch ligand prominently expressed in endothelial cells (EC). Exposure to hyperoxia in premature infants can disrupt the development and functions of cerebral blood vessels and lead to long-term cognitive impairment. However, its role in cerebral vascular development and the impact of postnatal hyperoxia on DLL4 expression in mouse brain EC have not been explored. We determined the DLL4 expression pattern and its downstream signalling gene expression in brain EC using Dll4+/+ and Dll4+/LacZ mice. We also performed in vitro studies using human brain microvascular endothelial cells. Finally, we determined Dll4 and Cldn5 expression in mouse brain EC exposed to postnatal hyperoxia. DLL4 is expressed in various cell types, with EC being the predominant one in immature brains. Moreover, DLL4 deficiency leads to persistent abnormalities in brain microvasculature and increased vascular permeability both in vivo and in vitro. We have identified that DLL4 insufficiency compromises endothelial integrity through the NOTCH-NICD-RBPJ-CLDN5 pathway, resulting in the downregulation of the tight junction protein claudin 5 (CLDN5). Finally, exposure to neonatal hyperoxia reduces DLL4 and CLDN5 expression in developing mouse brain EC. We reveal that DLL4 is indispensable for brain vascular development and maintaining the blood-brain barrier's function and is repressed by neonatal hyperoxia. We speculate that reduced DLL4 signalling in brain EC may contribute to the impaired brain development observed in neonates exposed to hyperoxia. KEY POINTS: The role of delta like 4 (DLL4), a Notch ligand in vascular endothelial cells, in brain vascular development and functions remains unknown. We demonstrate that DLL4 is expressed at a high level during postnatal brain development in immature brains and DLL4 insufficiency leads to abnormal cerebral vasculature and increases vascular permeability both in vivo and in vitro. We identify that DLL4  regulates endothelial integrity through NOTCH-NICD-RBPJ-CLDN5 signalling. Dll4 and Cldn5 expression are decreased in mouse brain endothelial cells exposed to postnatal hyperoxia.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Animais Recém-Nascidos , Proteínas de Ligação ao Cálcio , Claudina-5 , Células Endoteliais , Hiperóxia , Receptores Notch , Animais , Humanos , Camundongos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Encéfalo/metabolismo , Encéfalo/irrigação sanguínea , Encéfalo/crescimento & desenvolvimento , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/genética , Células Cultivadas , Claudina-5/metabolismo , Claudina-5/genética , Células Endoteliais/metabolismo , Hiperóxia/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Receptores Notch/metabolismo , Receptores Notch/genética , Transdução de Sinais
2.
Pediatr Res ; 92(5): 1299-1308, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35121849

RESUMO

BACKGROUND: An adverse maternal environment (AME) predisposes progeny towards cognitive impairment in humans and mice. Cognitive impairment associates with hippocampal dysfunction. An important regulator of hippocampal function is the hippocampal serotonergic system. Dysregulation of hippocampal serotonin receptor 2c (HTR2c) expression is linked with cognitive impairment. HTR2c contains multiple mRNA variants and isoforms that are epigenetically regulated including DNA methylation, histone modifications, and small nucleolar RNA MBII-52. We tested the hypotheses that AME increases HTR2c variant expression and alters epigenetic modifications along the HTR2c gene locus. METHODS: We create an AME through maternal Western diet and prenatal environmental stress in the mouse. We analyzed hippocampal HTR2c and variants' expression, DNA methylation and histone modifications along the gene locus, and MBII-52 levels in postnatal day 21 offspring. RESULTS: AME significantly increased the expressions of total HTR2c and full-length variants (V201 and V202) concurrently with an altered epigenetic profile along the HTR2c gene locus in male offspring hippocampi. Moreover, increased full-length variants' expression in AME males was in line with increased MBII-52 levels. CONCLUSIONS: AME affects male offspring hippocampal expression of HTR2c and full-length variants via epigenetic mechanisms. Altered hippocampal HTR2c expression may contribute to cognitive impairment seen in adult males in this model. IMPACT: The key message of our article is that an adverse maternal environment increases expression of total HTR2c mRNA and protein, alters proportions of HTR2c mRNA variants, and impacts HTR2c epigenetic modifications in male offspring hippocampi relative to controls. Our findings add to the literature by providing the first report of altered HTR2c mRNA variant expression in association with altered epigenetic modifications in the hippocampus of offspring mice exposed to an adverse maternal environment. Our findings suggest that an adverse maternal environment affects the expression of genes previously determined to regulate cognitive function through an epigenetic mechanism in a sex-specific manner.


Assuntos
Epigênese Genética , Hipocampo , Efeitos Tardios da Exposição Pré-Natal , Animais , Feminino , Masculino , Camundongos , Gravidez , Metilação de DNA , Hipocampo/metabolismo , Efeitos Tardios da Exposição Pré-Natal/metabolismo , RNA Mensageiro/metabolismo
3.
Dev Neurosci ; 43(2): 95-105, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33940573

RESUMO

An adverse maternal environment (AME) predisposes adult offspring toward cognitive impairment in humans and mice. However, the underlying mechanisms remain poorly understood. Epigenetic changes in response to environmental exposure may be critical drivers of this change. Epigenetic regulators, including microRNAs, have been shown to affect cognitive function by altering hippocampal neurogenesis which is regulated in part by brain-derived neurotropic factor (BDNF). We sought to investigate the effects of AME on miR profile and their epigenetic characteristics, as well as neurogenesis and BDNF expression in mouse hippocampus. Using our mouse model of AME which is composed of maternal Western diet and prenatal environmental stress, we found that AME significantly increased hippocampal miR-10b-5p levels. We also found that AME significantly decreased DNA methylation and increased accumulations of active histone marks H3 lysine (K) 4me3, H3K14ac, and -H3K36me3 at miR-10b promoter. Furthermore, AME significantly decreased hippocampal neurogenesis by decreasing cell numbers of Ki67+ (proliferation marker), NeuroD1+ (neuronal differentiation marker), and NeuN+ (mature neuronal marker) in the dentate gyrus (DG) region concurrently with decreased hippocampal BDNF protein levels. We speculate that the changes in epigenetic profile at miR-10b promoter may contribute to upregulation of miR-10b-5p and subsequently lead to decreased BDNF levels in a model of impaired offspring hippocampal neurogenesis and cognition in mice.


Assuntos
Fator Neurotrófico Derivado do Encéfalo , MicroRNAs , Animais , Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Epigênese Genética , Feminino , Hipocampo/metabolismo , Masculino , Camundongos , MicroRNAs/genética , Neurogênese , Gravidez
4.
J Nutr ; 151(10): 3102-3112, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34486661

RESUMO

BACKGROUND: The role of an adverse maternal environment (AME) in conjunction with a postweaning Western diet (WD) in the development of nonalcoholic fatty liver disease (NAFLD) in adult offspring has not been explored. Likewise, the molecular mechanisms associated with AME-induced NAFLD have not been studied. The fatty acid translocase or cluster of differentiation 36 (CD36) has been implicated to play a causal role in the pathogenesis of WD-induced steatosis. However, it is unknown if CD36 plays a role in AME-induced NAFLD. OBJECTIVE: This study was designed to evaluate the isolated and additive impact of AME and postweaning WD on the expression and DNA methylation of hepatic Cd36 in association with the development of NAFLD in a novel mouse model. METHODS: AME constituted maternal WD and maternal stress, whereas the control (Con) group had neither. Female C57BL/6J mice were fed a WD [40% fat energy, 29.1% sucrose energy, and 0.15% cholesterol (wt/wt)] 5 wk prior to pregnancy and throughout lactation. Non invasive variable stressors (random frequent cage changing, limited bedding, novel object, etc.) were applied to WD dams during the last third of pregnancy to produce an AME. Con dams consumed the control diet (CD) (10% fat energy, no sucrose or cholesterol) and were not exposed to stress. Male offspring were weaned onto either CD or WD, creating 4 experimental groups: Con-CD, Con-WD, AME-CD, and AME-WD, and evaluated for metabolic and molecular parameters at 120 d of age. RESULTS: AME and postweaning WD independently and additively increased the development of hepatic steatosis in adult male offspring. AME and WD independently and additively upregulated hepatic CD36 protein and mRNA expression and hypomethylated promoters 2 and 3 of the Cd36 gene. CONCLUSIONS: Using a mouse AME model together with postweaning WD, this study demonstrates a role for CD36 in AME-induced NAFLD in offspring and reveals 2 regions of environmentally induced epigenetic heterogeneity within Cd36.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Metilação de DNA , Dieta Hiperlipídica/efeitos adversos , Dieta Ocidental/efeitos adversos , Feminino , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Gravidez
5.
Pediatr Res ; 90(5): 998-1008, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-33603215

RESUMO

BACKGROUND: The brain of chronically ventilated preterm human infants is vulnerable to collateral damage during invasive mechanical ventilation (IMV). Damage is manifest, in part, by learning and memory impairments, which are hippocampal functions. A molecular regulator of hippocampal development is insulin-like growth factor 1 (IGF1). A gentler ventilation strategy is noninvasive respiratory support (NRS). We tested the hypotheses that NRS leads to greater levels of IGF1 messenger RNA (mRNA) variants and distinct epigenetic profile along the IGF1 gene locus in the hippocampus compared to IMV. METHODS: Preterm lambs were managed by NRS or IMV for 3 or 21 days. Isolated hippocampi were analyzed for IGF1 mRNA levels and splice variants for promoter 1 (P1), P2, and IGF1A and 1B, DNA methylation in P1 region, and histone covalent modifications along the gene locus. RESULTS: NRS had significantly greater levels of IGF1 P1 (predominant transcript), and 1A and 1B mRNA variants compared to IMV at 3 or 21 days. NRS also led to more DNA methylation and greater occupancy of activating mark H3K4 trimethylation (H3K4me3), repressive mark H3K27me3, and elongation mark H3K36me3 compared to IMV. CONCLUSIONS: NRS leads to distinct IGF1 mRNA variant levels and epigenetic profile in the hippocampus compared to IMV. IMPACT: Our study shows that 3 or 21 days of NRS of preterm lambs leads to distinct IGF1 mRNA variant levels and epigenetic profile in the hippocampus compared to IMV. Preterm infant studies suggest that NRS leads to better neurodevelopmental outcomes later in life versus IMV. Also, duration of IMV is directly related to hippocampal damage; however, molecular players remain unknown. NRS, as a gentler mode of respiratory management of preterm neonates, may reduce damage to the immature hippocampus through an epigenetic mechanism.


Assuntos
Animais Recém-Nascidos , Epigênese Genética , Hipocampo/metabolismo , Respiração Artificial/métodos , Somatomedinas/metabolismo , Animais , Metilação de DNA , Feminino , Histonas/metabolismo , Masculino , Regiões Promotoras Genéticas , Ovinos , Somatomedinas/genética
6.
Physiol Genomics ; 51(9): 462-470, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31373541

RESUMO

BACKGROUND: Fetal growth restriction (FGR) is a major risk factor for bronchopulmonary dysplasia (BPD). Maternal stress and poor diet are linked to FGR. Effect of perinatal stress on lung development remains unknown. OBJECTIVE: Using a murine model of adverse early life environment (AELE), we hypothesized that maternal exposure to perinatal environmental stress and high-fat diet (Western diet) lead to impaired lung development in the offspring. METHODS: Female mice were placed on either control diet or Western diet before conception. Those exposed to Western diet were also exposed to perinatal environmental stress, the combination referred to as AELE. Pups were either euthanized at postnatal day 21 (P21) or weaned to control diet and environment until adulthood (8-14 wk old). Lungs were harvested for histology, gene expression by quantitative RT-PCR, microRNA profiling, and immunoblotting. RESULTS: AELE increased the mean linear intercept and decreased the radial alveolar count and secondary septation in P21 and adult mice. Capillary count was also decreased in P21 and adult mice. AELE lungs had decreased vascular endothelial growth factor A (VEGFA), VEGF receptor 2, endothelial nitric oxide synthase, and hypoxia inducible factor-1α protein levels and increased expression of genes that regulate DNA methylation and upregulation of microRNAs that target genes involved in lung development at P21. CONCLUSION: AELE leads to impaired lung alveolar and vascular growth, which persists into adult age despite normalizing the diet and environment at P21. AELE also alters the expression of genes involved in lung remodeling.


Assuntos
Dieta Ocidental/efeitos adversos , Retardo do Crescimento Fetal/fisiopatologia , Pulmão/crescimento & desenvolvimento , Organogênese , Estresse Fisiológico/genética , Estresse Fisiológico/imunologia , Animais , Animais Recém-Nascidos , Metilação de DNA/genética , Modelos Animais de Doenças , Feminino , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Pulmão/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Óxido Nítrico Sintase/metabolismo , Gravidez , Transcriptoma , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo
7.
Physiol Genomics ; 50(11): 973-981, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30240345

RESUMO

Adverse early life environment (AELE) predisposes adult offspring toward anxiety disorders. Anxiety disorders are associated with prenatal injuries in key regions of the brain including prefrontal cortex (PFC), hippocampus (HP), and hypothalamus (HT). Injuries in these brain regions result in an impaired hypothalamus-pituitary-adrenal axis (HPA axis) and stress response. An important regulator of the stress response is FK506-binding protein 5 (FKBP5). FKBP5 is a cochaperone of the glucocorticoid receptor (GR) and inhibits GR-mediated regulatory feed-back on the HPA axis in response to stress. Human studies have shown that polymorphisms of FKBP5 are associated with higher FKBP5 levels. Increased FKBP5 leads to GR resistance and impaired negative feedback, which is associated with anxiety disorders. FKBP5 and its mRNA splice variants in the aforementioned brain regions have not been reported. We hypothesized that AELE will increase expression of FKBP5 and its mRNA splice variants in PFC, HP, and HT as well as increase anxiety in adult mice. AELE increased expression of FKBP5 and its mRNA variants in PFC, HP and HT at postnatal day 21. Additionally, AELE caused anxiety and increased GR abundance in association with these changes in FKBP5 expression. We speculate that these changes in FKBP5 mRNA variants affect HPA axis function and contributes to subsequent anxiety-like behavior later in life in AELE mice.


Assuntos
Ansiedade/etiologia , Encéfalo/fisiologia , Proteínas de Ligação a Tacrolimo/genética , Animais , Animais Recém-Nascidos , Ansiedade/genética , Comportamento Animal , Peso Corporal , Corticosterona/sangue , Feminino , Sistema Hipotálamo-Hipofisário/fisiologia , Masculino , Camundongos Endogâmicos C57BL , Microglia/fisiologia , Sistema Hipófise-Suprarrenal/fisiologia , Gravidez , Isoformas de Proteínas/genética , RNA Mensageiro/genética , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Estresse Psicológico/complicações , Proteínas de Ligação a Tacrolimo/metabolismo
8.
Physiol Genomics ; 50(10): 828-836, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30004838

RESUMO

Decreased expression of endothelial nitric oxide synthase (eNOS), a key mediator of perinatal transition, characterizes persistent pulmonary hypertension of the newborn (PPHN) in neonates and a fetal lamb model; the mechanisms are unclear. We investigated whether increased DNA CpG methylation at the eNOS promoter in estrogen response elements (EREs) and altered histone code together contribute to decreased eNOS expression in PPHN. We isolated pulmonary artery endothelial cells (PAEC) from fetal lambs with PPHN induced by prenatal ductus arteriosus constriction from 128 to 136 days gestation or gestation-matched twin controls. We measured right ventricular systolic pressure (RVSP) and Fulton index and determined eNOS expression in PAEC in control and PPHN lambs. We determined DNA CpG methylation by pyrosequencing and activity of ten eleven translocase demethylases (TET) by colorimetric assay. We quantified the occupancy of transcription factors, specificity protein 1 (Sp1), and estrogen receptors and density of four histone marks around Sp1 binding sites by chromatin immunoprecipitation (ChIP) assays. Fetal lambs with PPHN developed increased RVSP and Fulton index. Levels of eNOS mRNA and protein were decreased in PAEC from PPHN lambs. PPHN significantly increased the DNA CpG methylation in eNOS promoter and decreased TET activity in PAEC. PPHN decreased Sp1 occupancy and density of the active mark, lysine 12 acetylation of histone 4, and increased density of the repression mark, lysine 9 trimethylation of histone 3 around Sp1 binding sites in eNOS promoter. These results suggest that epigenetic modifications are primed to decrease Sp1 binding at the eNOS gene promoter in PPHN.


Assuntos
Células Endoteliais/metabolismo , Epigênese Genética , Hipertensão Pulmonar/genética , Óxido Nítrico Sintase Tipo III/genética , Artéria Pulmonar/metabolismo , Animais , Animais Recém-Nascidos , Células Cultivadas , Metilação de DNA , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Código das Histonas/genética , Hipertensão Pulmonar/embriologia , Hipertensão Pulmonar/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Gravidez , Regiões Promotoras Genéticas/genética , Artéria Pulmonar/embriologia , Artéria Pulmonar/patologia , Ovinos
9.
Am J Physiol Regul Integr Comp Physiol ; 309(2): R119-27, 2015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-25972460

RESUMO

Intrauterine growth restriction (IUGR) increases the risk for neurodevelopment delay and neuroendocrine reprogramming in both humans and rats. Neuroendocrine reprogramming involves the glucocorticoid receptor (GR) gene that is epigenetically regulated in the hippocampus. Using a well-characterized rodent model, we have previously shown that IUGR increases GR exon 1.7 mRNA variant and total GR expressions in male rat pup hippocampus. Epigenetic regulation of GR transcription may involve chromatin remodeling of the GR gene. A key chromatin remodeler is Brahma-related gene-1(Brg1), a member of the ATP-dependent SWItch/Sucrose NonFermentable (SWI/SNF) chromatin remodeling complex. Brg1 regulates gene expression by affecting nucleosome repositioning and recruiting transcriptional components to target promoters. We hypothesized that IUGR would increase hippocampal Brg1 expression and binding to GR exon 1.7 promoter, as well as alter nucleosome positioning over GR promoters in newborn male pups. Further, we hypothesized that IUGR would lead to accumulation of specificity protein 1 (Sp1) and RNA pol II at GR exon 1.7 promoter. Indeed, we found that IUGR increased Brg1 expression and binding to GR exon 1.7 promoter. We also found that increased Brg1 binding to GR exon 1.7 promoter was associated with accumulation of Sp1 and RNA pol II carboxy terminal domain pSer-5 (a marker of active transcription). Furthermore, the transcription start site of GR exon 1.7 was located within a nucleosome-depleted region. We speculate that changes in hippocampal Brg1 expression mediate GR expression and subsequently trigger neuroendocrine reprogramming in male IUGR rats.


Assuntos
Montagem e Desmontagem da Cromatina , DNA Helicases/metabolismo , Retardo do Crescimento Fetal/metabolismo , Hipocampo/metabolismo , Proteínas Nucleares/metabolismo , Regiões Promotoras Genéticas , Receptores de Glucocorticoides/metabolismo , Fatores de Transcrição/metabolismo , Animais , Animais Recém-Nascidos , Sítios de Ligação , DNA Helicases/genética , Modelos Animais de Doenças , Éxons , Retardo do Crescimento Fetal/genética , Retardo do Crescimento Fetal/fisiopatologia , Regulação da Expressão Gênica no Desenvolvimento , Hipocampo/crescimento & desenvolvimento , Hipocampo/fisiopatologia , Masculino , Proteínas Nucleares/genética , Nucleossomos/metabolismo , RNA Polimerase II/metabolismo , Ratos , Receptores de Glucocorticoides/genética , Fator de Transcrição Sp1/metabolismo , Fatores de Transcrição/genética , Sítio de Iniciação de Transcrição , Transcrição Gênica , Regulação para Cima
10.
Nutrients ; 15(9)2023 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-37432267

RESUMO

Exposure to adverse early-life environments (AME) increases the incidence of developing adult-onset non-alcoholic fatty liver disease (NAFLD). DNA methylation has been postulated to link AME and late-onset diseases. This study aimed to investigate whether and to what extent the hepatic DNA methylome was perturbed prior to the development of NAFLD in offspring exposed to AME in mice. AME constituted maternal Western diet and late-gestational stress. Male offspring livers at birth (d0) and weaning (d21) were used for evaluating the DNA methylome and transcriptome using the reduced representation of bisulfite sequencing and RNA-seq, respectively. We found AME caused 5879 differentially methylated regions (DMRs) and zero differentially expressed genes (DEGs) at d0 and 2970 and 123, respectively, at d21. The majority of the DMRs were distal to gene transcription start sites and did not correlate with DEGs. The DEGs at d21 were significantly enriched in GO biological processes characteristic of liver metabolic functions. In conclusion, AME drove changes in the hepatic DNA methylome, which preceded perturbations in the hepatic metabolic transcriptome, which preceded the onset of NAFLD. We speculate that subtle impacts on dynamic enhancers lead to long-range regulatory changes that manifest over time as gene network alternations and increase the incidence of NAFLD later in life.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Masculino , Animais , Camundongos , Gravidez , Feminino , Hepatopatia Gordurosa não Alcoólica/genética , Epigenoma , Transcriptoma , Metilação de DNA
11.
Anat Rec (Hoboken) ; 306(1): 162-175, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-35983908

RESUMO

An adverse maternal environment (AME) and Western diet (WD) in early life predispose offspring toward cognitive impairment in humans and mice. Cognitive impairment associates with hippocampal dysfunction. An important regulator of hippocampal function is the hippocampal Nociceptin/Orphanin FQ (N/OFQ) system. Previous studies find links between dysregulation of hippocampal N/OFQ receptor (NOP) expression and impaired cognitive function. NOP is encoded by the opioid receptor-like 1 (Oprl1) gene that contains multiple mRNA variants and isoforms. Regulation of Oprl1 expression includes histone modifications within the promoter. We tested the hypothesis that an AME and a postweaning WD increase the expression of hippocampal Oprl1 and select variants concurrent with altered histone code in the promoter. We created an AME-WD model combining maternal WD and prenatal environmental stress plus postweaning WD in the mouse. We analyzed the hippocampal expression of Oprl1, Oprl1 variants, and histone modifications in the Oprl1 promoter in offspring at postnatal day (P) 21 and P100. An AME and an AME-WD significantly increased the total hippocampal expression of Oprl1 and variant V4 concurrently with an increased accumulation of active histone marks in the promoter of male offspring. We concluded that an AME and an AME-WD alter hippocampal Oprl1 expression in offspring through an epigenetic mechanism in a variant-specific and sex-specific manner. Altered hippocampal Oprl1 expression may contribute to cognitive impairment seen in adult males in this model. Epigenetic regulation of Oprl1 is a potential mechanism by which an AME and a WD may contribute to neurocognitive impairment in male offspring.


Assuntos
Epigênese Genética , Animais , Humanos , Masculino , Camundongos
12.
Pediatr Res ; 72(1): 2-9, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22367251

RESUMO

INTRODUCTION: Uteroplacental insufficiency (UPI) produces significant neurodevelopmental deficits affecting the hippocampus of intrauterine growth-restricted (IUGR) offspring. IUGR males have worse deficits as compared with IUGR females. The exact mechanisms underlying these deficits are unclear. Alterations in hippocampal cellular composition along with altered expression of neural stem cell (NSC) differentiation molecules may underlie these deficits. We hypothesized that IUGR hippocampi would be endowed with altered neuronal, astrocytic, and immature oligodendrocytic proportions at birth, with males showing greater cellular deficits. We further hypothesized that UPI would perturb rat hippocampal expression of ErbB receptors (ErbB-Rs) and neuregulin 1 (NRG1) at birth and at weaning to account for the short- and long-term IUGR neurological sequelae. METHODS: A well-established rat model of bilateral uterine artery ligation at embryonic day 19.5 was used to induce IUGR. RESULTS: As compared with gender-matched controls, IUGR offspring have altered hippocampal neuronal, astrocytic, and immature oligodendrocytic composition in a subregion- and gender-specific manner at birth. In addition, IUGR hippocampi have altered receptor type- and gender-specific ErbB-R expression at birth and at weaning. DISCUSSION: These cellular and molecular alterations may account for the neurodevelopmental complications of IUGR and for the male susceptibility to worse neurologic outcomes.


Assuntos
Retardo do Crescimento Fetal/fisiopatologia , Hipocampo/fisiopatologia , Insuficiência Placentária/fisiopatologia , Receptor ErbB-2/metabolismo , Animais , Astrócitos/metabolismo , Diferenciação Celular/fisiologia , Feminino , Retardo do Crescimento Fetal/etiologia , Hipocampo/citologia , Ligadura , Masculino , Microscopia de Fluorescência , Células-Tronco Neurais/metabolismo , Neuregulina-1/metabolismo , Oligodendroglia/metabolismo , Gravidez , Ratos , Fatores Sexuais , Artéria Uterina/cirurgia
13.
Physiol Genomics ; 43(20): 1160-9, 2011 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-21828247

RESUMO

Intrauterine growth retardation (IUGR) predisposes humans toward hippocampal morbidities, such as impaired learning and memory. Hippocampal dual specificity phosphatase 5 (DUSP5) may be involved in these morbidities because DUSP5 regulates extracellular signal-regulated kinase phosphorylation (Erk). In the rat, IUGR causes postnatal changes in hippocampal gene expression and epigenetic characteristics. However, the impact of IUGR upon hippocampal DUSP5 expression and epigenetic characteristics is not known. We therefore hypothesized that IUGR affects hippocampal 1) DUSP5 expression, DNA CpG methylation, and histone code, and 2) erk1/2 phosphorylation in a well-characterized rat model of IUGR. We found that IUGR significantly decreased DUSP5 expression in the day of life (DOL) 0 and 21 male rat, while decreasing only DUSP5 protein levels in the DOL21 female rat. Fluorescent in situ hybridization and immunohistochemistry analyses localized the changes in DUSP5 mRNA and protein, many of which occurred in the dentate gyrus. IUGR also caused sex-specific differences in DNA CpG methylation and histone code in two sites of the hippocampal DUSP5 gene, a 5'-flanking specificity protein-1 (SP1) site and exon 2. Finally, when IUGR decreased DUSP5 protein levels, Erk phosphorylation increased. We conclude that IUGR affects hippocampal DUSP5 expression and epigenetic characteristics in a sex-specific manner.


Assuntos
Fosfatases de Especificidade Dupla/genética , Epigênese Genética , Retardo do Crescimento Fetal/enzimologia , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Hipocampo/enzimologia , Animais , Ilhas de CpG/genética , Metilação de DNA/genética , Fosfatases de Especificidade Dupla/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Retardo do Crescimento Fetal/patologia , Hipocampo/patologia , Código das Histonas , Imuno-Histoquímica , Hibridização in Situ Fluorescente , Masculino , Fosforilação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos
14.
Physiol Genomics ; 42(2): 177-89, 2010 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-20388836

RESUMO

Studies in humans and rats suggest that intrauterine growth retardation (IUGR) permanently resets the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis reprogramming may involve persistently altered expression of the hippocampal glucocorticoid receptor (hpGR), an important regulator of HPA axis reactivity. Persistent alteration of gene expression, long after the inciting event, is thought to be mediated by epigenetic mechanisms that affect mRNA and mRNA variant expression. GR mRNA variants in both humans and rats include eleven 5'-end variants and GRalpha, the predominant 3'-end variant. The 3'-end variants associated with glucocorticoid resistance in humans (GRbeta, GRgamma, GRA, and GRP) have not been reported in rats. We hypothesized that in the rat hippocampus IUGR would decrease total GR mRNA, increase GRbeta, GRgamma, GRA, and GRP, and affect epigenetics of the GR gene at birth (D0) and at 21 days of life (D21). IUGR increased hpGR and exon 1.7 hpGR mRNA in males at D0 and D21, associated with increased trimethyl H3/K4 at exon 1.7 at both time points. IUGR also increased hpGRgamma in males at D0 and D21, associated with increased acetyl H3/K9 at exon 3 at both time points. hpGRA increased in female IUGR rats at D0 and D21. In addition, our data support the existence of hpGRbeta and hpGRP in the rat. IUGR has sex-specific, persistent effects on GR expression and its histone code. We speculate that postnatal changes in hippocampal GR variant and total mRNA expression may underlie IUGR-associated HPA axis reprogramming.


Assuntos
Epigênese Genética , Retardo do Crescimento Fetal/genética , Hipocampo/metabolismo , Receptores de Glucocorticoides/genética , Animais , Imunoprecipitação da Cromatina , Feminino , Retardo do Crescimento Fetal/metabolismo , Humanos , Masculino , RNA Mensageiro/metabolismo , Ratos , Receptores de Glucocorticoides/metabolismo
15.
Physiol Rep ; 8(8): e14407, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32333646

RESUMO

Adverse maternal environment (AME) and high-fat diet in early childhood increase the risk of cognitive impairment and depression later in life. Cognitive impairment associates with hippocampal dysfunction. A key regulator of hippocampal function is the glucocorticoid receptor. Increased hippocampal GR expression associates with cognitive impairment and depression. Transcriptional control of GR relies in part upon the DNA methylation status at multiple alternative initiation sites that are tissue specific, with exon 1.7 being hippocampal specific. Increased exon 1.7 expression associates with upregulated hippocampal GR expression in early life stress animal models. However, the effects of AME combined with postweaning western diet (WD) on offspring behaviors and the expression of GR exon 1 variants in the hippocampus are unknown. We hypothesized that AME and postweaning WD would impair cognitive function and cause depression-like behavior in offspring in conjunction with dysregulated hippocampal expression of total GR and exon 1.7 variant in mice. We found that AME-WD impaired learning and memory in male adult offspring concurrently with increased hippocampal expression of total GR and GR 1.7. We also found that increased GR 1.7 expression was associated with decreased DNA methylation at the GR 1.7 promoter. We speculate that decreased DNA methylation at the GR 1.7 promoter plays a role in AME-WD induced increase of GR in the hippocampus. This increased GR expression may subsequently contribute to hippocampus dysfunction and lead to the cognitive impairment seen in this model.


Assuntos
Disfunção Cognitiva/genética , Disfunção Cognitiva/metabolismo , Metilação de DNA , Dieta Ocidental/efeitos adversos , Hipocampo/metabolismo , Exposição Materna/efeitos adversos , Receptores de Glucocorticoides/genética , Animais , Disfunção Cognitiva/patologia , Feminino , Desenvolvimento Fetal , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Masculino , Troca Materno-Fetal , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Regiões Promotoras Genéticas , Distribuição Aleatória , Receptores de Glucocorticoides/biossíntese , Receptores de Glucocorticoides/metabolismo
16.
Birth Defects Res ; 110(20): 1551-1555, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30576090

RESUMO

BACKGROUND: Cardiac fibrosis is a cardinal feature of multiple types of cardiovascular disease, which lead to heart failure. Multiple studies connect adverse maternal environment (AME) with cardiac fibrosis. AME does not always result in fibrosis, though. An additional "insult", such as an adult Western diet (WD), is frequently necessary. The additive effects of AME and adult WD on cardiac fibrosis is not well-understood. AME can also alter DNA methylation. DNA methyltransferase (DNMT) and ten-eleven translocation (TET) are methylation modifying genes that regulate DNA methylation, but it is unknown if AME changes cardiac gene expression of DNMT and TET. We sought to use a model of AME and adult WD to investigate the development of cardiac fibrosis and cardiac mRNA expression of DNMT and TET genes. METHODS: We exposed dams to WD or control diet (CD) 5 weeks before pregnancy and through lactation. We added environmental stressors during the last third of pregnancy to dams on WD to create AME. Dams on CD experienced no added stressors to create control maternal environment (CME). Male offspring were weaned at Postnatal Week 3 (W3) and placed on WD or CD to create four groups: CME-CD, CME-WD, AME-CD, and AME-WD. RESULTS: AME-WD increased cardiac fibrosis in adulthood (p < .05), whereas AME-CD and CME-WD did not. TET1-3 and DNMT3a mRNA levels decreased in AME versus CME offspring (p < .01). CONCLUSION: AME increases susceptibility to cardiac fibrosis in adult male mice. Early-life changes to TET expression may mediate susceptibility to fibrosis, but further testing is needed.


Assuntos
Fibrose/etiologia , Exposição Materna/efeitos adversos , Miocárdio/patologia , Animais , Doenças Cardiovasculares/etiologia , DNA (Citosina-5-)-Metiltransferase 1/genética , DNA (Citosina-5-)-Metiltransferase 1/fisiologia , Metilação de DNA , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/fisiologia , Dieta Ocidental/efeitos adversos , Feminino , Fibrose/genética , Coração/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/fisiologia
17.
Int J Dev Neurosci ; 55: 56-65, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27666383

RESUMO

BACKGROUND: Adverse maternal lifestyle resulting in adverse early life environment (AELE) increases risks for neuropsychiatric disorders in offspring. Neuropsychiatric disorders are associated with impaired neurogenesis and neuro-inflammation in the hippocampus (HP). Microglia are neuro-inflammatory cells in the brain that regulate neurogenesis via toll-like receptors (TLR). TLR-9 is implicated in neurogenesis inhibition and is responsible for stress-related inflammatory responses. We hypothesized that AELE would increase microglia cell count and increase TLR-9 expression in juvenile mouse HP. These increases in microglia cell count and TLR-9 expression would be associated with decrease neural stem cell count and neuronal cell count. METHODS: We developed a mouse model of AELE combining Western diet and a stress environment. Stress environment consisted of random change from embryonic day 13 (E13) to E17 as well as static change in maternal environment from E13 to postnatal day 21(P21). At P21, we measured hippocampal cell numbers of microglia, neural stem cell and neuron, as well as hippocampal TLR-9 expression. RESULTS: AELE significantly increased total microglia number and TLR-9 expression in the hippocampus. Concurrently, AELE significantly decreased neural stem cell and neuronal numbers. CONCLUSIONS: AELE increased the neuro-inflammatory cellular response in the juvenile HP. We speculate that increased neuro-inflammatory responses may contribute to impaired neurogenesis seen in this model.


Assuntos
Meio Ambiente , Hipocampo/patologia , Microglia/patologia , Células-Tronco Neurais/fisiologia , Efeitos Tardios da Exposição Pré-Natal/patologia , Fatores Etários , Análise de Variância , Animais , Animais Recém-Nascidos , Antígenos CD/metabolismo , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Células Cultivadas , Dieta Ocidental , Modelos Animais de Doenças , Feminino , Citometria de Fluxo , Hipocampo/crescimento & desenvolvimento , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Nestina/metabolismo , Fosfopiruvato Hidratase/metabolismo , Gravidez , Efeitos Tardios da Exposição Pré-Natal/dietoterapia , RNA Mensageiro/metabolismo , Receptor Toll-Like 9/genética , Receptor Toll-Like 9/metabolismo
18.
Int J Dev Neurosci ; 38: 59-67, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25107645

RESUMO

Intrauterine growth restriction (IUGR) programs neurodevelopmental impairment and long-term neurological morbidities. Neurological morbidities in IUGR infants are correlated with changes hippocampal volume. We previously demonstrated that IUGR alters hippocampal cellular composition in both neonatal and juvenile rat pups in association with altered hippocampal gene expression and epigenetic determinants. PPARγ signaling is important for neurodevelopment as well as epigenetic integrity in the brain via the PPARγ-Setd8-H4K20me(1) axis and Wnt signaling. We hypothesized that IUGR would decrease expression of PPARγ, Setd8, and H4K20me(1) in juvenile rat hippocampus. We further hypothesized that reduced PPARγ-Setd8-H4K20me(1) would be associated with reduced Wnt signaling genes Wnt3a and ß-catenin, and wnt target gene Axin2. To test our hypothesis we used a rat model of uteroplacental insufficiency-induced IUGR. We demonstrated that PPARγ localizes to oligodendrocytes, neurons and astrocytes within the juvenile rat hippocampus. We also demonstrated that IUGR reduces levels of PPARγ, Setd8 and H4K20me(1) in male and female juvenile rat hippocampus in conjunction with reduced Wnt signaling components in only male rats. We speculate that reduced PPARγ and Wnt signaling may contribute to altered hippocampal cellular composition which, in turn, may contribute to impaired neurodevelopment and subsequent neurocognitive impairment in IUGR offspring.


Assuntos
Retardo do Crescimento Fetal/patologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Hipocampo/metabolismo , Hipocampo/fisiopatologia , PPAR gama/metabolismo , Via de Sinalização Wnt/fisiologia , Actinas/genética , Actinas/metabolismo , Animais , Animais Recém-Nascidos , Peso Corporal , Modelos Animais de Doenças , Feminino , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/metabolismo , Masculino , PPAR gama/genética , Fosfopiruvato Hidratase/metabolismo , RNA Mensageiro , Ratos , Fatores Sexuais
19.
Syst Biol Reprod Med ; 59(4): 184-90, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23631676

RESUMO

Fetal growth restriction (FGR) is associated with impaired neurodevelopmental outcomes in affected newborns. The pathogenesis of FGR-associated neurodevelopmental impairment implicates abnormal hippocampal function. The steroid hormone estrogen and its receptor, estrogen receptor alpha (ERα), are involved in the normal programming of hippocampal development and structure. However, the impact of FGR on hippocampal estrogen and hippocampal ERα is not well characterized. We hypothesized that FGR will reduce hippocampal and serum levels of 17-beta estradiol and its receptor, ERα, in the newborn rat hippocampus. We further hypothesize that FGR will reduce hippocampal ERα levels in a region-specific manner. To test our hypotheses, we used the well characterized rat model of FGR induced by uteroplacental-insufficiency in the pregnant Sprague-Dawley rat. Hippocampi and serum were obtained from FGR and control day 0 rat pups and examined for hippocampal 17-beta estradiol, serum 17-beta estradiol, and ERα mRNA and protein levels. Immunohistochemistry was performed to examine region-specific ERα staining. FGR decreased hippocampal 17-beta estradiol levels in the hippocampi of male newborn rats but not females. Serum 17-beta estradiol levels were not affected by FGR in either gender. FGR decreased hippocampal ERα mRNA levels in males but not females. Hippocampal ERα protein levels by Western blotting were not affected by FGR. However, FGR decreased apparent ERα staining in the cornu ammonis (CA)1, CA3, and dentate gyrus regions in the hippocampi of male newborn rats but not females. We conclude that FGR affects the programming of hippocampal estrogen and hippocampal ERα levels in the newborn rat in a gender-specific manner.


Assuntos
Estradiol/sangue , Receptor alfa de Estrogênio/metabolismo , Retardo do Crescimento Fetal/fisiopatologia , Hipocampo/metabolismo , Animais , Animais Recém-Nascidos , Feminino , Hipocampo/embriologia , Imuno-Histoquímica , Masculino , Gravidez , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley
20.
J Neurotrauma ; 29(11): 2075-85, 2012 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-22413999

RESUMO

Traumatic brain injury (TBI) is a major cause of acquired cognitive disability in childhood. Such disability may be blunted by enhancing the brain's endogenous neuroprotective response. An important endogenous neuroprotective response is the insulin-like growth factor-1 (IGF-1) mRNA variant, IGF-1B. IGF-1B mRNA, characterized by exon 5 inclusion, encodes the IGF-1 and Eb peptides. IGF-1A mRNA excludes exon 5 and encodes the IGF-1 and Ea peptides. A region in the human IGF-1B homologue acts as an exon-splicing enhancer (ESE) to increase IGF-1B mRNA. It is not known if TBI is associated with increased brain IGF-1B mRNA. Epigenetic modifications may underlie altered gene expression in the brain after TBI. We hypothesized that TBI would increase hippocampal IGF-1B mRNA in 17-day-old rats, associated with DNA methylation and/or histone modifications at the promoter site 1 (P1) or exon 5/ESE region. Hippocampi from rat pups after controlled cortical impact (CCI) were used to measure IGF-1B mRNA, DNA methylation, and histone modifications at the P1, P2, and exon5/ESE regions. In CCI hippocampi, IGF-1B mRNA peaked at post-injury day (PID) 2 (1700±320% sham), but normalized by PID 14. IGF-1A peaked at PID 3 (280±52% sham), and remained elevated at PID 14. Increased IGF-1B mRNA was associated with increased methylation at P1, and increased histone modifications associated with gene activation at P2 and exon5/ESE, together with differential methylation in the exon 5/ESE regions. We report for the first time that hippocampal IGF-1B mRNA increased after developmental TBI. We speculate that epigenetic modifications at the P2 and exon 5/ESE regions are important in the regulation of IGF-1B mRNA expression. The exon 5/ESE region may present a means for future therapies to target IGF-1B transcription after TBI.


Assuntos
Lesões Encefálicas/genética , Epigênese Genética/genética , Hipocampo/metabolismo , Fator de Crescimento Insulin-Like I/genética , Regiões Promotoras Genéticas , Animais , Lesões Encefálicas/metabolismo , Imunoprecipitação da Cromatina , Modelos Animais de Doenças , Éxons/genética , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , RNA Mensageiro/análise , RNA Mensageiro/genética , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa
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