scholarly journals Altered Hippocampal Gene Expression and Morphology in Fetal Piglets following Maternal Respiratory Viral Infection

2018 ◽  
Vol 40 (2) ◽  
pp. 104-119 ◽  
Author(s):  
Adrienne M. Antonson ◽  
Bindu Balakrishnan ◽  
Emily C. Radlowski ◽  
Geraldine Petr ◽  
Rodney W. Johnson

Maternal infection during pregnancy increases the risk of neurobehavioral problems in offspring. Evidence from rodent models indicates that the maternal immune response to infection can alter fetal brain development, particularly in the hippocampus. However, information on the effects of maternal viral infection on fetal brain development in gyrencephalic species is limited. Thus, the objective of this study was to assess several effects of maternal viral infection in the last one-third of gestation on hippocampal gene expression and development in fetal piglets. Pregnant gilts were inoculated with porcine reproductive and respiratory syndrome virus (PRRSV) at gestational day (GD) 76 and the fetuses were removed by cesarean section at GD 111 (3 days before anticipated parturition). The gilts infected with PRRSV had elevated plasma interleukin-6 levels and developed transient febrile and anorectic responses lasting approximately 21 days. Despite having a similar overall body weight, fetuses from the PRRSV-infected gilts had a decreased brain weight and altered hippocampal gene expression compared to fetuses from control gilts. Notably, maternal infection caused a reduction in estimated neuronal numbers in the fetal dentate gyrus and subiculum. The number of proliferative Ki-67+ cells was not altered, but the relative integrated density of GFAP+ staining was increased, in addition to an increase in GFAP gene expression, indicating astrocyte-specific gliosis. Maternal viral infection caused an increase in fetal hippocampal gene expression of the inflammatory cytokines TNF-α and IFN-γ and the myelination marker myelin basic protein. MHCII protein, a classic monocyte activation marker, was reduced in microglia, while expression of the MHCII gene was decreased in hippocampal tissue of the fetuses from PRRSV-infected gilts. Together, these data suggest that maternal viral infection at the beginning of the last trimester results in a reduction in fetal hippocampal neurons that is evident 5 weeks after infection, when fetal piglets are near full term. The neuronal reduction was not accompanied by pronounced neuroinflammation at GD 111, indicating that any activation of classic neuroinflammatory pathways by maternal viral infection, if present, is mostly resolved by parturition.

2021 ◽  
Author(s):  
◽  
Monica P. Strawn

Two experiments were conducted to investigate molecular regulation that impacts fetal brain development in pigs. In the first experiment (Chapter 2), gene expression was profiled by RNA sequencing (RNA-seq) to examine the whole transcriptome of the male (M) and female (F) fetal brain at gestation day (d) 45, 60 and 90. The analysis showed fewer differentially expressed genes (DEGs) in the brain of male and female fetuses in earlier gestation (d45-d60) when compared to late gestation (d60-d90). The homeobox (HOX) A5 gene that regulates pattern formation in early development was in the top upregulated DEGs between d45 to d60 in fetuses of both sexes. This study also found HOX B5 and D3 genes were in the top upregulated genes between d45 and d60 of the fetal brain of females, but not males. The second experiment (Chapter 3) investigated DNA methylation in pigs. DNA methylation in the fetal brain of both sexes at the same three gestation days was performed by enzymatic methyl sequencing (EM-seq). Hotspots of methylation in specific chromosomal regions were observed in the analysis. The analysis identified 1,475 sites in the pig genome that were methylated in the fetal brain, irrespective of sex, during development. The same sites were methylated in a canonically correlated manner in the blood of the adult stage, both in sows and boars. This is consistent with the Dilman theory of developmental aging (DevAge), which suggests that aging and early development of the brain are regulated by common molecular processes. A comparative analysis (Chapter 4) compared the gene expression patterns in the fetal brain and placenta between pigs and mice. The analysis identified 112 genes that were expressed (mean FPKM > 10) in the fetal brain of both species but not expressed (mean FPKM < 1) in the placenta of either species, and 10 genes that were expressed in the placenta of both species but not expressed in the fetal brain. In-silico analysis of the transcription factor binding sites in the 500 bp of the upstream DNA of these common genes revealed that they were commonly regulated by the RE1 silencing transcription factor (REST), which is a multifaceted transcription factor that acts as a master regulator of neurogenesis as well as controls neural excitation and the aging processes.


2021 ◽  
Vol 14 ◽  
Author(s):  
Parul Varma ◽  
Zane R. Lybrand ◽  
Mariah C. Antopia ◽  
Jenny Hsieh

Pregnant women are at greater risk of infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), because of their altered immunity and strained cardiovascular system. Emerging studies of placenta, embryos, and cerebral organoids suggest that fetal organs including brain could also be vulnerable to coronavirus disease 2019 (COVID-19). Additionally, a case study from Paris has reported transient neurological complications in neonates born to pregnant mothers. However, it remains poorly understood whether the fetal brain expresses cellular components that interact with Spike protein (S) of coronaviruses, which facilitates fusion of virus and host cell membrane and is the primary protein in viral entry. To address this question, we analyzed the expression of known (ACE2, TMPRSS2, and FURIN) and novel (ZDHHC5, GOLGA7, and ATP1A1) S protein interactors in publicly available fetal brain bulk and single cell RNA sequencing datasets. Bulk RNA sequencing analysis across multiple regions of fetal brain spanning 8 weeks post conception (wpc)−37wpc indicates that two of the known S protein interactors are expressed at low levels with median normalized gene expression values ranging from 0.08 to 0.06 (ACE2) and 0.01–0.02 (TMPRSS2). However, the third known S protein interactor FURIN is highly expressed (11.1–44.09) in fetal brain. Interestingly, all three novel S protein interactors are abundantly expressed throughout fetal brain development with median normalized gene expression values ranging from 20.38–21.60 (ZDHHC5), 92.47–68.35 (GOLGA7), and 65.45–194.5 (ATP1A1). Moreover, the peaks of expression of novel interactors is around 12–26wpc. Using publicly available single cell RNA sequencing datasets, we further show that novel S protein interactors show higher co-expression with neurons than with neural progenitors and astrocytes. These results suggest that even though two of the known S protein interactors are present at low levels in fetal brain, novel S protein interactors are abundantly present and could play a direct or indirect role in SARS-CoV-2 fetal brain pathogenesis, especially during the 2nd and 3rd trimesters of pregnancy.


Author(s):  
M.V. Medvedev, O.I. Kozlova, À.Yu. Romanova

Fetal brain was retrospectively evaluated in 418 normal fetuses at 16–28 weeks of gestation. The multiplanar mode to obtain the axial cerebral plane and measured the width of the cavum septum pellucidum (CSP) and biparietal diameter (BD). All measurements of CSP were done from as the widest diameter across both borders in an inter-to inter fashion. The CSP width is increasing at second trimester of gestation. Normal range plotted on the reference range (mean, 5th and 95th percentiles) of fetal width CSP by measuring of its size may be useful for assessment of fetal brain development in the second trimester of gestation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexis Papariello ◽  
David Taylor ◽  
Ken Soderstrom ◽  
Karen Litwa

AbstractThe endocannabinoid system (ECS) plays a complex role in the development of neural circuitry during fetal brain development. The cannabinoid receptor type 1 (CB1) controls synaptic strength at both excitatory and inhibitory synapses and thus contributes to the balance of excitatory and inhibitory signaling. Imbalances in the ratio of excitatory to inhibitory synapses have been implicated in various neuropsychiatric disorders associated with dysregulated central nervous system development including autism spectrum disorder, epilepsy, and schizophrenia. The role of CB1 in human brain development has been difficult to study but advances in induced pluripotent stem cell technology have allowed us to model the fetal brain environment. Cortical spheroids resemble the cortex of the dorsal telencephalon during mid-fetal gestation and possess functional synapses, spontaneous activity, an astrocyte population, and pseudo-laminar organization. We first characterized the ECS using STORM microscopy and observed synaptic localization of components similar to that which is observed in the fetal brain. Next, using the CB1-selective antagonist SR141716A, we observed an increase in excitatory, and to a lesser extent, inhibitory synaptogenesis as measured by confocal image analysis. Further, CB1 antagonism increased the variability of spontaneous activity within developing neural networks, as measured by microelectrode array. Overall, we have established that cortical spheroids express ECS components and are thus a useful model for exploring endocannabinoid mediation of childhood neuropsychiatric disease.


Author(s):  
Rachel L. Leon ◽  
Imran N. Mir ◽  
Christina L. Herrera ◽  
Kavita Sharma ◽  
Catherine Y. Spong ◽  
...  

Abstract Children with congenital heart disease (CHD) are living longer due to effective medical and surgical management. However, the majority have neurodevelopmental delays or disorders. The role of the placenta in fetal brain development is unclear and is the focus of an emerging field known as neuroplacentology. In this review, we summarize neurodevelopmental outcomes in CHD and their brain imaging correlates both in utero and postnatally. We review differences in the structure and function of the placenta in pregnancies complicated by fetal CHD and introduce the concept of a placental inefficiency phenotype that occurs in severe forms of fetal CHD, characterized by a myriad of pathologies. We propose that in CHD placental dysfunction contributes to decreased fetal cerebral oxygen delivery resulting in poor brain growth, brain abnormalities, and impaired neurodevelopment. We conclude the review with key areas for future research in neuroplacentology in the fetal CHD population, including (1) differences in structure and function of the CHD placenta, (2) modifiable and nonmodifiable factors that impact the hemodynamic balance between placental and cerebral circulations, (3) interventions to improve placental function and protect brain development in utero, and (4) the role of genetic and epigenetic influences on the placenta–heart–brain connection. Impact Neuroplacentology seeks to understand placental connections to fetal brain development. In fetuses with CHD, brain growth abnormalities begin in utero. Placental microstructure as well as perfusion and function are abnormal in fetal CHD.


1996 ◽  
Vol 19 (2-3) ◽  
pp. 141-149 ◽  
Author(s):  
John H. Gilmore ◽  
Diana O. Perkins ◽  
Mark A. Kliewer ◽  
Marvin L. Hage ◽  
Susan G. Silva ◽  
...  

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