scholarly journals Shared loci of telomere length with brain morphology, and pleiotropy in transcriptomic and epigenomic profiles of brain

2020 ◽  
Author(s):  
Gita A Pathak ◽  
Frank Wendt ◽  
Daniel F Levey ◽  
Adam Mecca ◽  
Christopher van Dyck ◽  
...  
Keyword(s):  
Telomere Length ◽  
Fetal Brain ◽  
Neuropsychiatric Disorders ◽  
Adult Brain ◽  
Brain Morphology ◽  
M Cell ◽  
Total N ◽  
Cell Cycle Transition ◽  
Calcium Ion Transport ◽  
Shared Genetic

Premature shortening of telomere length is observed in neuropsychiatric disorders. We tested genetic colocalization of seven and nine leukocyte telomere length (LTL) loci in two ancestry groups, European (EUR) and East-Asian (EAS), respectively (total n=60,601) with brain morphology measures for 101 region-of-interests (ROI) (n=21,821). The posterior probability (>90%) was observed for fourth ventricle, gray matter and cerebellar vermal lobules I-IV volumes. We found regulatory genes (p ≤ 2.47 x10-6) by integrating transcriptomic (EAS=4;EUR=5) and methylation data (EUR=17; EAS=4) of brain tissues using Summary-based Mendelian Randomization (SMR). The LTL SNP associations were tested for brain-based chromatin profiles using H-MAGMA (EUR=50; EAS=97; p<= 1.02 x10-6). Pathway enrichment of tissue-specific genes highlighted calcium ion transport (fetal brain) and G2/M cell cycle transition (adult brain). This study provides evidence that previously reported LTL associations with neuropsychiatric disorders could be related to a shared genetic relationship between LTL and brain structural and regulatory traits.

scholarly journals Fetal brain sparing in a mouse model of chronic maternal hypoxia

2017 ◽  
Vol 39 (6) ◽  
pp. 1172-1184 ◽  
Author(s):  
Lindsay S Cahill ◽  
Johnathan Hoggarth ◽  
Jason P Lerch ◽  
Mike Seed ◽  
Christopher K Macgowan ◽  
...  
Keyword(s):  
Blood Flow ◽  
Mouse Model ◽  
Chronic Hypoxia ◽  
Fetal Brain ◽  
Adult Brain ◽  
Brain Morphology ◽  
Ductus Venosus ◽  
Experimental Mouse Model ◽  
Experimental Mouse ◽  
Maternal Hypoxia

Hypoxic stress is a common occurrence during human pregnancy, yet little is known about its effects on the fetal brain. This study examined the fetal hemodynamic responses to chronic hypoxia in an experimental mouse model of chronic maternal hypoxia (11% O2 from E14.5 to E17.5). Using high-frequency Doppler ultrasound, we found fetal cerebral and ductus venosus blood flow were both elevated by 69% and pulmonary blood flow was decreased by 62% in the fetuses exposed to chronic hypoxia compared to controls. This demonstrates that brain sparing persists during chronic fetal hypoxia and is mediated by “streaming,” where highly oxygenated blood preferentially flows through the ductus venosus towards the cerebral circulation, bypassing the liver and the lungs. Consistent with these changes in blood flow, the fetal brain volume measured by MRI is preserved, while the liver and lung volumes decreased compared to controls. However, hypoxia exposed fetuses were rendered vulnerable to an acute hypoxic challenge (8% O2 for 3 min), demonstrating global blood flow decreases consistent with imminent fetal demise rather than elevated cerebral blood flow. Despite this vulnerability, there were no differences in adult brain morphology in the mice exposed to chronic maternal hypoxia compared to controls.

scholarly journals Genetic polymorphism of CYP2C19 and subcortical variability in the human adult brain

2020 ◽  
Author(s):  
Julia C. Stingl ◽  
Catharina Scholl ◽  
Julia E. Bosch ◽  
Roberto Viviani
Keyword(s):  
Genetic Polymorphism ◽  
Fetal Brain ◽  
Positive Association ◽  
Hippocampal Volume ◽  
Volume Estimation ◽  
Adult Brain ◽  
Brain Morphology ◽  
Cytochrome P450 Enzymes ◽  
Endogenous Substrates

AbstractPharmacogenetic studies have shown involvement of cytochrome P450 enzymes in the metabolism of psychotropic drugs. However, expression and activity on endogenous substrates in the brain may underlie a constitutive role of these enzymes beyond drug metabolism. CYP2C19, which is expressed in the human fetal brain during neurodevelopment, shows affinity for endogenous compounds including monoaminergic neurotransmitters, steroid hormones, and endocannabinoids. In this study (N=608), we looked at the genetic polymorphism of CYP2C19 and its potential associations with structural phenotypes of subcortical brain volume with structural imaging. Using two independent volume estimation techniques, we found converging evidence for a positive association between CYP2C19 activity scores, as inferred from the genotype, and basal ganglia and hippocampal volume. This association was present only in female individuals, raising the possibility that effects on brain morphology may arise through a mechanism involving the metabolism of estrogen steroids.

scholarly journals Genetic polymorphism of CYP2C19 and subcortical variability in the human adult brain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Julia C. Stingl ◽  
Catharina Scholl ◽  
Julia E. Bosch ◽  
Roberto Viviani
Keyword(s):  
Genetic Polymorphism ◽  
Fetal Brain ◽  
Positive Association ◽  
Hippocampal Volume ◽  
Volume Estimation ◽  
Adult Brain ◽  
Brain Morphology ◽  
Cytochrome P450 Enzymes ◽  
Endogenous Substrates

AbstractPharmacogenetic studies have shown involvement of cytochrome P450 enzymes in the metabolism of psychotropic drugs. However, expression and activity on endogenous substrates in the brain may underlie a constitutive role of these enzymes beyond drug metabolism. CYP2C19, which is expressed in the human fetal brain during neurodevelopment, shows affinity for endogenous compounds including monoaminergic neurotransmitters, steroid hormones, and endocannabinoids. In this study (N = 608), we looked at the genetic polymorphism of CYP2C19 and its potential associations with structural phenotypes of subcortical brain volume with structural imaging. Using two independent volume estimation techniques, we found converging evidence for a positive association between CYP2C19 activity scores, as inferred from the genotype, and basal ganglia and hippocampal volume. This association was present only in female individuals, raising the possibility that effects on brain morphology may arise through a mechanism involving the metabolism of estrogen steroids.

scholarly journals Transfer of rhodamine-123 into the brain and cerebrospinal fluid of fetal, neonatal and adult rats

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Liam M. Koehn ◽  
Katarzyna M. Dziegielewska ◽  
Mark D. Habgood ◽  
Yifan Huang ◽  
Norman R. Saunders
Keyword(s):  
Cerebrospinal Fluid ◽  
Fetal Brain ◽  
Maternal Blood ◽  
Adult Brain ◽  
Rhodamine 123 ◽  
Patient Specific ◽  
Adult Rats ◽  
Blood Brain ◽  
The Brain ◽  
Brain Barriers

Abstract Background Adenosine triphosphate binding cassette transporters such as P-glycoprotein (PGP) play an important role in drug pharmacokinetics by actively effluxing their substrates at barrier interfaces, including the blood-brain, blood-cerebrospinal fluid (CSF) and placental barriers. For a molecule to access the brain during fetal stages it must bypass efflux transporters at both the placental barrier and brain barriers themselves. Following birth, placental protection is no longer present and brain barriers remain the major line of defense. Understanding developmental differences that exist in the transfer of PGP substrates into the brain is important for ensuring that medication regimes are safe and appropriate for all patients. Methods In the present study PGP substrate rhodamine-123 (R123) was injected intraperitoneally into E19 dams, postnatal (P4, P14) and adult rats. Naturally fluorescent properties of R123 were utilized to measure its concentration in blood-plasma, CSF and brain by spectrofluorimetry (Clariostar). Statistical differences in R123 transfer (concentration ratios between tissue and plasma ratios) were determined using Kruskal-Wallis tests with Dunn’s corrections. Results Following maternal injection the transfer of R123 across the E19 placenta from maternal blood to fetal blood was around 20 %. Of the R123 that reached fetal circulation 43 % transferred into brain and 38 % into CSF. The transfer of R123 from blood to brain and CSF was lower in postnatal pups and decreased with age (brain: 43 % at P4, 22 % at P14 and 9 % in adults; CSF: 8 % at P4, 8 % at P14 and 1 % in adults). Transfer from maternal blood across placental and brain barriers into fetal brain was approximately 9 %, similar to the transfer across adult blood-brain barriers (also 9 %). Following birth when placental protection was no longer present, transfer of R123 from blood into the newborn brain was significantly higher than into adult brain (3 fold, p < 0.05). Conclusions Administration of a PGP substrate to infant rats resulted in a higher transfer into the brain than equivalent doses at later stages of life or equivalent maternal doses during gestation. Toxicological testing of PGP substrate drugs should consider the possibility of these patient specific differences in safety analysis.

scholarly journals MYC-targeted WDR4 promotes proliferation, metastasis, and sorafenib resistance by inducing CCNB1 translation in hepatocellular carcinoma

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Peng Xia ◽  
Hao Zhang ◽  
Kequan Xu ◽  
Xiang Jiang ◽  
Meng Gao ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Epithelial Mesenchymal Transition ◽  
P53 Protein ◽  
Rna Modifications ◽  
M Cell ◽  
Mesenchymal Transition ◽  
Akt Phosphorylation ◽  
Repeat Domain ◽  
Cell Cycle Transition

AbstractHepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. However, there still remains a lack of effective diagnostic and therapeutic targets for this disease. Increasing evidence demonstrates that RNA modifications play an important role in the progression of HCC, but the role of the N7-methylguanosine (m7G) methylation modification in HCC has not been properly evaluated. Thus, the goal of the present study was to investigate the function and mechanism of the m7G methyltransferase WD repeat domain 4 (WDR4) in HCC as well as its clinical relevance and potential value. We first verified the high expression of WDR4 in HCC and observed that upregulated WDR4 expression increased the m7G methylation level in HCC. WDR4 promoted HCC cell proliferation by inducing the G2/M cell cycle transition and inhibiting apoptosis in addition to enhancing metastasis and sorafenib resistance through epithelial-mesenchymal transition (EMT). Furthermore, we observed that c-MYC (MYC) can activate WDR4 transcription and that WDR4 promotes CCNB1 mRNA stability and translation to enhance HCC progression. Mechanistically, we determined that WDR4 enhances CCNB1 translation by promoting the binding of EIF2A to CCNB1 mRNA. Furthermore, CCNB1 was observed to promote PI3K and AKT phosphorylation in HCC and reduce P53 protein expression by promoting P53 ubiquitination. In summary, we elucidated the MYC/WDR4/CCNB1 signalling pathway and its impact on PI3K/AKT and P53. Furthermore, the result showed that the m7G methyltransferase WDR4 is a tumour promoter in the development and progression of HCC and may act as a candidate therapeutic target in HCC treatment.

scholarly journals Insulin and insulinlike growth factor 1 (IGF-1) receptors during central nervous system development: expression of two immunologically distinct IGF-1 receptor beta subunits.

1989 ◽  
Vol 9 (7) ◽  
pp. 2806-2817 ◽  
Author(s):  
R S Garofalo ◽  
O M Rosen
Keyword(s):  
Growth Factor ◽  
Tyrosine Kinase ◽  
System Development ◽  
Fetal Brain ◽  
Nervous System Development ◽  
Adult Brain ◽  
Beta Subunit ◽  
Tyrosine Kinase Domain ◽  
Beta Subunits ◽  
Insulinlike Growth Factor

Insulin and insulinlike growth factor 1 (IGF-1) receptors are present in brain, yet their function remains obscure. Expression of these tyrosine kinase-bearing growth factor receptors during rat brain development was examined by using three antipeptide antibodies directed against epitopes in the beta subunits (AbP2, AbP4, and AbP5). All three antibodies recognized both insulin and IGF-1 receptors. Membranes were prepared from fetal brains (14 to 21 days of gestation), neonatal brain (postnatal day 1), and adult brain. Immunoblot analyses using AbP4 and AbP5 revealed a 92-kilodalton (kDa) protein that corresponded to the beta subunit of the insulin and IGF-1 receptors. Densitometric scanning of immunoblots indicated that receptor proteins were 4- to 10-fold more abundant in fetal brain membranes than in membranes from adult brain. Expression was highest during 16 to 18 days of gestation and declined thereafter to the relatively low level found in adult brain. Immunoblot analyses with AbP2 as well as ligand-activated receptor autophosphorylation revealed an additional protein of 97 kDa. This protein was phosphorylated in response to IGF-1 and was not directly recognized by AbP4 or AbP5. The covalent association of the 97-kDa protein with the 92-kDa beta subunit was indicated by the ability of AbP4 and AbP5 to immunoprecipitate both proteins under nonreducing conditions but only the 92-kDa protein after reduction. In contrast, AbP2 immunoprecipitated both proteins regardless of their association. This immunospecificity remained unchanged after deglycosylation of the isolated proteins. Two-dimensional tryptic phosphopeptide analysis showed that the 92- and 97-kDa subunits of the IGF-1 receptor are related but distinct proteins. Taken together, the data suggest that the 92- and 97-kDa subunits differ in primary amino acid sequence. Thus, two distinct beta subunits may be present in a single IGF-1 receptor in brain. These subunits have in common an epitope recognized by an antibody to the tyrosine kinase domain (AbP2) but differ in regions thought to be important in receptor kinase regulation and signal transduction.

scholarly journals Importance of Adult Dmbx1 in Long-Lasting Orexigenic Effect of Agouti-Related Peptide

Endocrinology ◽  
2016 ◽  
Vol 157 (1) ◽  
pp. 245-257 ◽  
Author(s):  
Seiichiro Hirono ◽  
Eun Young Lee ◽  
Shunsuke Kuribayashi ◽  
Takahiro Fukuda ◽  
Naokatsu Saeki ◽  
...  
Keyword(s):  
Mouse Strain ◽  
Energy Homeostasis ◽  
Expression Patterns ◽  
Critical Role ◽  
Fetal Brain ◽  
Cre Recombinase ◽  
Calcitonin Gene Related Peptide ◽  
Adult Brain ◽  
Related Peptide ◽  
Calcitonin Gene

Abstract Dmbx1 is a brain-specific homeodomain transcription factor expressed primarily during embryogenesis, and its systemic disruption (Dmbx1−/−) in the ICR mouse strain resulted in leanness associated with impaired long-lasting orexigenic effect of agouti-related peptide (AgRP). Because spatial and temporal expression patterns of Dmbx1 change dramatically during embryogenesis, it remains unknown when and where Dmbx1 plays a critical role in energy homeostasis. In the present study, the physiological roles of Dmbx1 were examined by its conditional disruption (Dmbx1loxP/loxP) in the C57BL/6 mouse strain. Although Dmbx1 disruption in fetal brain resulted in neonatal lethality, its disruption by synapsin promoter-driven Cre recombinase, which eliminated Dmbx1 expression postnatally, exempted the mice (Syn-Cre;Dmbx1loxP/loxP mice) from lethality. Syn-Cre;Dmbx1loxP/loxP mice show mild leanness and impaired long-lasting orexigenic action of AgRP, demonstrating the physiological relevance of Dmbx1 in the adult. Visualization of Dmbx1-expressing neurons in adult brain using the mice harboring tamoxifen-inducible Cre recombinase in the Dmbx1 locus (Dmbx1CreERT2/+ mice) revealed Dmbx1 expression in small numbers of neurons in restricted regions, including the lateral parabrachial nucleus (LPB). Notably, c-Fos expression in LPB was increased at 48 hours after AgRP administration in Dmbx1loxP/loxP mice but not in Syn-Cre;Dmbx1loxP/loxP mice. These c-Fos-positive neurons in LPB did not coincide with neurons expressing Dmbx1 or melanocortin 4 receptor but did coincide with those expressing calcitonin gene-related peptide. Accordingly, Dmbx1 in the adult LPB is required for the long-lasting orexigenic effect of AgRP via the neural circuitry involving calcitonin gene-related peptide neurons.

Regulation of N-myc gene expression: use of an adenovirus vector to demonstrate posttranscriptional control

1990 ◽  
Vol 10 (12) ◽  
pp. 6700-6708
Author(s):  
L E Babiss ◽  
J M Friedman
Keyword(s):  
Recombinant Adenovirus ◽  
Wilms Tumor ◽  
Fetal Brain ◽  
Adenovirus Vector ◽  
Cell Types ◽  
Adult Brain ◽  
Posttranscriptional Control ◽  
Equivalent Rate ◽  
Myc Gene ◽  
Recombinant Adenovirus Vector

We present evidence that differences in the levels of N-myc mRNA among different cell types are the result of posttranscriptional control. First, we noted that while steady-state mouse N-myc mRNA could be detected only in fetal mouse brain, it was transcribed at an equivalent rate in adult brain, liver, spleen, and placenta and in fetal brain. Similarly, the human N-myc gene was transcribed at an equivalent rate in HeLa cells, which do not accumulate this RNA in the cytoplasm, and cell lines G401 (a Wilms tumor-derived cell line) and SKNMc (established from a primitive neuroepithelioma), which do express N-myc RNA. As expected, the N-myc promoter functioned at equivalent rates, as demonstrated by the level of a reporter gene, when introduced into these cell types by using a recombinant adenovirus vector. The suggestion that posttranscriptional mechanisms control the level of this RNA was supported by the observation that sequences in the N-myc third exon specifically decreased the level of E1A mRNA when these sequences were placed downstream of the E1A promoter in a recombinant adenovirus. Finally, we further localized these sequences to a 600-bp fragment of the third exon by introducing various subclones of this sequence downstream of the E1A promoter in both viral and plasmid vectors.

scholarly journals The Expression and Distributions of ANP32A in the Developing Brain

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shanshan Wang ◽  
Yunliang Wang ◽  
Qingshan Lu ◽  
Xinshan Liu ◽  
Fuyu Wang ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Fetal Brain ◽  
Tissue Expression ◽  
Developing Brain ◽  
Adult Brain ◽  
Mammalian Brain ◽  
Dependent Manner ◽  
Growing Up ◽  
Embryonic Mouse ◽  
And Function

Acidic (leucine-rich) nuclear phosphoprotein 32 family, member A (ANP32A), has multiple functions involved in neuritogenesis, transcriptional regulation, and apoptosis. However, whether ANP32A has an effect on the mammalian developing brain is still in question. In this study, it was shown that brain was the organ that expressed the most abundant ANP32A by human multiple tissue expression (MTE) array. The distribution of ANP32A in the different adult brain areas was diverse dramatically, with high expression in cerebellum, temporal lobe, and cerebral cortex and with low expression in pons, medulla oblongata, and spinal cord. The expression of ANP32A was higher in the adult brain than in the fetal brain of not only humans but also mice in a time-dependent manner. ANP32A signals were dispersed accordantly in embryonic mouse brain. However, ANP32A was abundant in the granular layer of the cerebellum and the cerebral cortex when the mice were growing up, as well as in the Purkinje cells of the cerebellum. The variation of expression levels and distribution of ANP32A in the developing brain would imply that ANP32A may play an important role in mammalian brain development, especially in the differentiation and function of neurons in the cerebellum and the cerebral cortex.

scholarly journals Characterization of human fetal brain endothelial cells reveals barrier properties suitable for in vitro modeling of the BBB with syngenic co-cultures

2017 ◽  
Vol 38 (5) ◽  
pp. 888-903 ◽  
Author(s):  
Allison M Andrews ◽  
Evan M Lutton ◽  
Lee A Cannella ◽  
Nancy Reichenbach ◽  
Roshanak Razmpour ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Neurovascular Unit ◽  
Fetal Brain ◽  
Barrier Properties ◽  
Endothelial Activation ◽  
Fetal Tissue ◽  
In Vitro Models ◽  
Adult Brain ◽  
Alternative Source

Endothelial cells (ECs) form the basis of the blood–brain barrier (BBB), a physical barrier that selectively restricts transport into the brain. In vitro models can provide significant insight into BBB physiology, mechanisms of human disease pathology, toxicology, and drug delivery. Given the limited availability of primary human adult brain microvascular ECs ( aBMVECs), human fetal tissue offers a plausible alternative source for multiple donors and the opportunity to build syngenic tri-cultures from the same host. Previous efforts to culture fetal brain microvascular ECs ( fBMVECs) have not been successful in establishing mature barrier properties. Using optimal gestational age for isolation and flow cytometry cell sorting, we show for the first time that fBMVECs demonstrate mature barrier properties. fBMVECs exhibited similar functional phenotypes when compared to aBMVECs for barrier integrity, endothelial activation, and gene/protein expression of tight junction proteins and transporters. Importantly, we show that tissue used to culture fBMVECs can also be used to generate a syngenic co-culture, creating a microfluidic BBB on a chip. The findings presented provide a means to overcome previous challenges that limited successful barrier formation by fBMVECs. Furthermore, the source is advantageous for autologous reconstitution of the neurovascular unit for next generation in vitro BBB modeling.

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