Browsing by Subject "Neurodevelopment"

Now showing 1 - 6 of 6
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    5-hydroxymethylcytosine is dynamically regulated during forebrain organoid development and aberrantly altered in Alzheimer’s disease
    (Cell Press, 2021-04-27) Kuehner, Janise N.; Chen, Junyu; Bruggeman, Emily C.; Wang, Feng; Li, Yangping; Xu, Chongchong; McEachin, Zachary T.; Li, Ziyi; Chen, Li; Hales, Chadwick M.; Wen, Zhexing; Yang, Jingjing; Yao, Bing; Medicine, School of Medicine
    5-hydroxymethylcytosine (5hmC) undergoes dynamic changes during mammalian brain development, and its dysregulation is associated with Alzheimer's disease (AD). The dynamics of 5hmC during early human brain development and how they contribute to AD pathologies remain largely unexplored. We generate 5hmC and transcriptome profiles encompassing several developmental time points of healthy forebrain organoids and organoids derived from several familial AD patients. Stage-specific differentially hydroxymethylated regions demonstrate an acquisition or depletion of 5hmC modifications across developmental stages. Additionally, genes concomitantly increasing or decreasing in 5hmC and gene expression are enriched in neurobiological or early developmental processes, respectively. Importantly, our AD organoids corroborate cellular and molecular phenotypes previously observed in human AD brains. 5hmC is significantly altered in developmentally programmed 5hmC intragenic regions in defined fetal histone marks and enhancers in AD organoids. These data suggest a highly coordinated molecular system that may be dysregulated in these early developing AD organoids.
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    Efficacy of a 4-part program on brain development
    (Cambridge University Press, 2018-06) Silver, Emily; Michael, Nancy; Medicine, School of Medicine
    OBJECTIVES/SPECIFIC AIMS: (1) Provide basic brain knowledge about development and resiliency. (2) Develop an understanding of how a mother can impact a child’s brain development. (3) Foster a sense of agency to increase the likelihood that a mother will enact positive changes. (4) Develop the ability to recognize a connection between one’s own behaviors and a child’s development and behaviors. METHODS/STUDY POPULATION: Tested the efficacy of a 4-week intervention program on neurodevelopment for homeless mothers. Mothers (n=4) residing at the Center for the Homeless in South Bend, IN were recruited. Used community partner feedback, weekly surveys, and pre/post tests to look at changes in basic content knowledge, behavioral change, and self-efficacy. RESULTS/ANTICIPATED RESULTS: Preliminary results indicate an increase in knowledge about neurodevelopment, although results on behavioral changes are inconclusive. The program is anticipated to run a second time with a new group of parents residing in the Center for the Homeless to increase sample size. DISCUSSION/SIGNIFICANCE OF IMPACT: Anticipated that the results will add to the existing literature concerning effective interventions in strengthening parenting and neuroscience knowledge in vulnerable populations.
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    The Enduring Consequences of Prenatal Opioid Exposure
    (2022-02) Grecco, Gregory Giovanni; Sheets, Patrick; Atwood, Brady; Yamamoto, Bryan; McKinzie, David; Yoder, Karmen
    The opioid crisis has resulted in an unprecedented number of neonates born with prenatal opioid exposure; however, the long-term effects of opioid exposure on offspring behavior and neurodevelopment remain relatively unknown. I developed a translational mouse model of prenatal methadone exposure (PME) that resembles the typical pattern of opioid use by pregnant women who first use oxycodone then switch to methadone maintenance pharmacotherapy, and subsequently become pregnant while maintained on methadone. PME produced substantial impairments in offspring growth, sensorimotor milestone acquisition, and activity in an open field. Furthermore, these behavioral alterations were associated with significant disruptions in the primary motor cortex (M1). Notably, layer 5 pyramidal neurons of the M1 displayed significantly increased voltage sag which is primarily mediated by HCN1 channels. Interestingly, the α2-adrenergic receptor, a known modulator of HCN1 channels, displayed significantly increased expression in the M1 of PME animals. The locomotor activity in an open field was significantly reduced following in vivo pharmacological activation of the α2-adrenergic receptor with clonidine in PME offspring suggesting this may be therapeutic target for the hyperactivity associated with prenatal exposure to opioids. Previous work has also described an association between prenatal opioid exposure and alterations in opioid reward-related behavior; however, the effect of PME on alcohol reward remains undetermined. Given the widespread accessibility and usage, alcohol represents the most likely addictive substance the growing population of opioid exposed neonates will encounter as they age. I discovered that PME disrupts conditioned preference for alcohol, enhances the locomotor stimulating effects of alcohol, and increases alcohol consumption in a sex-dependent manner. This alcohol-reward phenotype in PME offspring was associated with altered excitatory neurotransmission and disrupted cannabinoid-mediated long-term depression (CB-LTD) in the dorsolateral striatum, an important substrate involved in compulsive drug use. Further work is required to determine the specific inputs at which CB-LTD is disrupted and if restoring this form of plasticity in PME animals prevents the enhanced alcohol addiction phenotype.
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    Generating intravital super-resolution movies with conventional microscopy reveals actin dynamics that construct pioneer axons
    (The Company of Biologists, 2019-03-08) Zhang, Yide; Nichols, Evan L.; Zellmer, Abigail M.; Guldner, Ian H.; Kankel, Cody; Zhang, Siyuan; Howard, Scott S.; Smith, Cody J.; Medicine, School of Medicine
    Super-resolution microscopy is broadening our in-depth understanding of cellular structure. However, super-resolution approaches are limited, for numerous reasons, from utilization in longer-term intravital imaging. We devised a combinatorial imaging technique that combines deconvolution with stepwise optical saturation microscopy (DeSOS) to circumvent this issue and image cells in their native physiological environment. Other than a traditional confocal or two-photon microscope, this approach requires no additional hardware. Here, we provide an open-access application to obtain DeSOS images from conventional microscope images obtained at low excitation powers. We show that DeSOS can be used in time-lapse imaging to generate super-resolution movies in zebrafish. DeSOS was also validated in live mice. These movies uncover that actin structures dynamically remodel to produce a single pioneer axon in a 'top-down' scaffolding event. Further, we identify an F-actin population - stable base clusters - that orchestrate that scaffolding event. We then identify that activation of Rac1 in pioneer axons destabilizes stable base clusters and disrupts pioneer axon formation. The ease of acquisition and processing with this approach provides a universal technique for biologists to answer questions in living animals.
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    Iron deficiency reduces synapse formation in the Drosophila clock circuit
    (Humana Press, 2019-05) Rudisill, Samuel S.; Martin, Bradley R.; Mankowski, Kevin M.; Tessier, Charles R.; Medical and Molecular Genetics, School of Medicine
    Iron serves as a critical cofactor for proteins involved in a host of biological processes. In most animals, dietary iron is absorbed in enterocytes and then disseminated for use in other tissues in the body. The brain is particularly dependent on iron. Altered iron status correlates with disorders ranging from cognitive dysfunction to disruptions in circadian activity. The exact role iron plays in producing these neurological defects, however, remains unclear. Invertebrates provide an attractive model to study the effects of iron on neuronal development since many of the genes involved in iron metabolism are conserved, and the organisms are amenable to genetic and cytological techniques. We have examined synapse growth specifically under conditions of iron deficiency in the Drosophila circadian clock circuit. We show that projections of the small ventrolateral clock neurons to the protocerebrum of the adult Drosophila brain are significantly reduced upon chelation of iron from the diet. This growth defect persists even when iron is restored to the diet. Genetic neuronal knockdown of ferritin 1 or ferritin 2, critical components of iron storage and transport, does not affect synapse growth in these cells. Together, these data indicate that dietary iron is necessary for central brain synapse formation in the fly and further validate the use of this model to study the function of iron homeostasis on brain development.
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    Toward early estimation and treatment of addiction vulnerability: radial arm maze and N-acetyl cysteine before cocaine sensitization or nicotine self-administration in neonatal ventral hippocampal lesion rats
    (Springer-Verlag, 2016-12) Rao, Kalyan N.; Sentir, Alena M.; Engleman, Eric A.; Bell, Richard L.; Hulvershorn, Leslie A.; Breier, Alan; Chambers, R. Andrew; Department of Psychiatry, IU School of Medicine
    RATIONAL: Prefrontal cortical (PFC)-hippocampal-striatal circuits, interconnected via glutamatergic signaling, are dysfunctional in mental illnesses that involve addiction vulnerability. OBJECTIVES: In healthy and neurodevelopmentally altered rats, we examined how Radial Arm Maze (RAM) performance estimates addiction vulnerability, and how starting a glutamatergic modulating agent, N-acetyl cysteine (NAC) in adolescence alters adult mental illness and/or addiction phenotypes. METHODS: Rats with neonatal ventral hippocampal lesions (NVHL) vs. SHAM-operated controls were randomized to NAC vs. saline in adolescence followed by cognitive testing (RAM) in early adulthood and then cocaine behavioral sensitization (experiment 1; n = 80) or nicotine self-administration (experiment 2; n = 12). RESULTS: In experiment 1, NVHL rats showed over-consumption of food (Froot-Loops (FL)) baiting the RAM with poor working memory (low-arm entries to repeat (ETR)), producing an elevated FL to ETR ratio ("FLETR"; p < 0.001). FLETR was the best linear estimator (compared to FL or ETR) of magnitude of long-term cocaine sensitization (R (2) = 0.14, p < 0.001). NAC treatment did not alter FL, ETR, FLETR, or cocaine sensitization. In experiment 2, FLETR also significantly and uniquely correlated with subsequent drug seeking during nicotine-induced reinstatement after extinction of nicotine self-administration (R (2) = 0.47, p < 0.01). NAC did not alter RAM performance, but significantly reversed NVHL-induced increases in nicotine seeking during extinction and reinstatement. CONCLUSIONS: These findings demonstrate the utility of animal models of mental illness with addiction vulnerability for developing novel diagnostic measures of PFC-hippocampal-striatal circuit dysfunction that may reflect addiction risk. Such tests may direct pharmacological treatments prior to adulthood and addictive drug exposure, to prevent or treat adult addictions.