Medical Biochemistry Commons^™

Disruption Of The Placenta–Brain Axis In Transgenic Mice Lacking Serotonin Transporter (Sert) In Trophoblast Cells, David T. Ellenberger, Zhen Lyu, Rosalind T. B. Herrington, Jessica A. Kinkade, Gustavo W. Leone, Ji Ying Sze, Nathan J. Bivens, R. Frank Baker, R. Michael Roberts, Trupti Joshi, Cheryl S. Rosenfeld

Biomedical Sciences

Serotonin reuptake inhibitors (SSRIs) are commonly prescribed to pregnant women experiencing depression. Such drugs, however, might adversely affect placenta and fetal brain development. Parietal trophoblast giant cells (pTGCs) in the mouse placenta are postulated to internalize maternal serotonin (5-HT) via transport through SERT, encoded by Slc6a4, and to provide the initial source of 5-HT to the emerging brain via the placental–brain axis. Genetic deletion of Slc6a4 in pTGCs has been hypothesized to impact placental and fetal brain development. A transgenic mouse line with high-affinity SERT, encoded by Slc6a4, was selectively deleted by pairing mice with Cre recombinase linked …

Abnormal Morphology And Synaptogenic Signaling In Astrocytes Following Prenatal Opioid Exposure, Ethan B. Niebergall, Daron Weekley, Anna Mazur, Nathan A. Olszewski, Kayla M. Deschepper, N. Radant, Aishwarya S. Vijay

Biomedical Sciences

In recent decades, there has been a dramatic rise in the rates of children being born after in utero exposure to drugs of abuse, particularly opioids. Opioids have been shown to have detrimental effects on neurons and glia in the central nervous system (CNS), but the impact of prenatal opioid exposure (POE) on still-developing synaptic circuitry is largely unknown. Astrocytes exert a powerful influence on synaptic development, secreting factors to either promote or inhibit synapse formation and neuronal maturation in the developing CNS. Here, we investigated the effects of the partial µ-opioid receptor agonist buprenorphine on astrocyte synaptogenic signaling and …

Alterations In Excitatory And Inhibitory Synaptic Development Within The Mesolimbic Dopamine Pathway In A Mouse Model Of Prenatal Drug Exposure, Taylor Boggess, James C. Williamson, Ethan B. Niebergall, Hannah Sexton, Richard D. Egleton, Larry Grover, Chris Risher

Biomedical Sciences

The rise in rates of opioid abuse in recent years in the United States has led to a dramatic increase in the incidence of neonatal abstinence syndrome (NAS). Despite improved understanding of NAS and its acute symptoms, there remains a paucity of information regarding the long-term effects of prenatal exposure to drugs of abuse on neurological development. The primary goal of this study was to investigate the effects of prenatal drug exposure on synaptic connectivity within brain regions associated with the mesolimbic dopamine pathway, the primary reward pathway associated with drug abuse and addiction, in a mouse model. Our secondary …

Astrocyte-Derived Thrombospondin Induces Cortical Synaptogenesis In A Sex-Specific Manner, Anna Mazur, Ean H. Bills, Kayla M. Deschepper, James C. Williams, Brandon J. Henderson, W. Christopher Risher

Biomedical Sciences

The regulation of synaptic connectivity in the brain is vital to proper functioning and development of the CNS. Formation of neural networks in the CNS has been shown to be heavily influenced by astrocytes, which secrete factors, including thrombospondin (TSP) family proteins, that promote synaptogenesis. However, whether this process is different between males and females has not been thoroughly investigated. In this study, we found that cortical neurons purified from newborn male rats showed a significantly more robust synaptogenic response compared with female-derived cells when exposed to factors secreted from astrocytes. This difference was driven largely by the neuronal response …

Thrombospondin Receptor Α2Δ-1 Promotes Synaptogenesis And Spinogenesis Via Postsynaptic Rac1, W. Chris Risher, Namsoo Kim, Sehwon Koh, Ji‑Eun Cho, Petar Mitev, Erin F. Spence, Louis‑Jan Pilaz, Dongqing Wang, Guoping Feng, Debra L. Silver, Scott H. Soderling, Henry H. Yin, Cagla Eroglu

Biomedical Sciences

Astrocytes control excitatory synaptogenesis by secreting thrombospondins (TSPs), which function via their neuronal receptor, the calcium channel subunit α2δ-1. α2δ-1 is a drug target for epilepsy and neuropathic pain; thus the TSP–α2δ-1 interaction is implicated in both synaptic development and disease pathogenesis. However, the mechanism by which this interaction promotes synaptogenesis and the requirement for α2δ-1 for connectivity of the developing mammalian brain are unknown. In this study, we show that global or cell-specific loss of α2δ-1 yields profound deficits in excitatory synapse numbers, ultrastructure, and activity and severely stunts spinogenesis in the mouse cortex. Postsynaptic but not presynaptic α2δ-1 …

Adolescent Intermittent Alcohol Exposure: Deficits In Object Recognition Memory And Forebrain Cholinergic Markers, H. Scott Swartzwelder, Shawn K. Acheson, Kelsey M. Miller, Hannah G. Sexton, Wen Liu, Fulton T. Crews, Mary-Louise Risher

Biomedical Sciences

The long-term effects of intermittent ethanol exposure during adolescence (AIE) are of intensive interest and investigation. The effects of AIE on learning and memory and the neural functions that drive them are of particular interest as clinical findings suggest enduring deficits in those cognitive domains in humans after ethanol abuse during adolescence. Although studies of such deficits after AIE hold much promise for identifying mechanisms and therapeutic interventions, the findings are sparse and inconclusive. The present results identify a specific deficit in memory function after AIE and establish a possible neural mechanism of that deficit that may be of translational …

Platelet-Activating Factor Receptor Affects Food Intake And Body Weight, Wei Li, Thomas M. Mcintyre

Biomedical Sciences

“Let’s Move!” is a comprehensive initiative, launched by the First Lady, Michelle Obama, dedicates to solving problems of obesity, which is growing in child. The life behaviors do affect obesity; however, the mechanistic insight in molecular level is still not clear. In this study, by continually monitoring mouse body weight under chow and high fat western diets as well as metabolic, physical activity and food intake behaviors assessed in a CLAMS Comprehensive Lab Animal Monitoring System, we demonstrated that the platelet-activating factor receptor (PTAFR) contributes to modification of life behaviors. PTAFR does not affect metabolism of ingested dietary fat and …

The Sox9 Upstream Region Prone To Chromosomal Aberrations Causing Campomelic Dysplasia Contains Multiple Cartilage Enhancers, Baojin Yao, Qiuqing Wang, Chia-Feng Liu, Pallavi Bhattaram, Wei Li, Timothy J. Mead, James F. Crish, Véronique Lefebvre

Biomedical Sciences

Two decades after the discovery that heterozygous mutations within and around SOX9 cause campomelic dysplasia, a generalized skeleton malformation syndrome, it is well established that SOX9 is a master transcription factor in chondrocytes. In contrast, the mechanisms whereby translocations in the –350/–50-kb region 5 of SOX9 cause severe disease and whereby SOX9 expression is specified in chondrocytes remain scarcely known. We here screen this upstream region and uncover multiple enhancers that activate Sox9-promoter transgenes in the SOX9 expression domain. Three of them are primarily active in chondrocytes. E250 (located at – 250 kb) confines its activity to condensed prechondrocytes, …

Effects Of Acute Or Chronic Ethanol Exposure During Adolescence On Behavioral Inhibition And Efficiency In A Modified Water Maze Task, Shawn K. Acheson, Craig Bearison, Mary-Louise Risher, Sabri H. Abdelwahab, Wilkie A. Wilson, H. Scott Swartzwelder

Biomedical Sciences

Ethanol is well known to adversely affect frontal executive functioning, which continues to develop throughout adolescence and into young adulthood. This is also a developmental window in which ethanol is misused by a significant number of adolescents. We examined the effects of acute and chronic ethanol exposure during adolescence on behavioral inhibition and efficiency using a modified water maze task. During acquisition, rats were trained to find a stable visible platform onto which they could escape. During the test phase, the stable platform was converted to a visible floating platform (providing no escape) and a new hidden platform was added …

Long-Term Effects Of Chronic Intermittent Ethanol Exposure In Adolescent And Adult Rats: Radial-Arm Maze Performance And Operant Food Reinforced Responding, Mary-Louise Risher, Rebekah L. Fleming, Nathalie Boutros, Svetlana Semenova, Wilkie A. Wilson, Edward D. Levin, Athina Markou, H. Scott Swartzwelder, Shawn K. Acheson

Biomedical Sciences

Background: Adolescence is not only a critical period of late-stage neurological development in humans, but is also a period in which ethanol consumption is often at its highest. Given the prevalence of ethanol use during this vulnerable developmental period we assessed the long-term effects of chronic intermittent ethanol (CIE) exposure during adolescence, compared to adulthood, on performance in the radial-arm maze (RAM) and operant food-reinforced responding in male rats.

Methodology/Principal Findings: Male Sprague Dawley rats were exposed to CIE (or saline) and then allowed to recover. Animals were then trained in either the RAM task or an operant task using …

Increased Hemorrhagic Transformation And Altered Infarct Size And Localization After Experimental Stroke In A Rat Model Type 2 Diabetes, Adviye Ergul, Mostafa M. Elgebaly, Mary-Louise Risher, Weiguo Li, Hazem Elewa, Jeffrey A. Switzer, Christiana Hall, Anna Kozak, Susan C. Fagan

Biomedical Sciences

Background: Interruption of flow through of cerebral blood vessels results in acute ischemic stroke. Subsequent breakdown of the blood brain barrier increases cerebral injury by the development of vasogenic edema and secondary hemorrhage known as hemorrhagic transformation (HT). Diabetes is a risk factor for stroke as well as poor outcome of stroke. The current study tested the hypothesis that diabetes-induced changes in the cerebral vasculature increase the risk of HT and augment ischemic injury.

Methods: Diabetic Goto-Kakizaki (GK) or control rats underwent 3 hours of middle cerebral artery occlusion and 21 h reperfusion followed by evaluation of infarct size, hemorrhage …