Publications by authors named "Kathryn M Harper"

Article Synopsis
  • Sleep disruption and Tau accumulation are linked to cognitive decline in Alzheimer's disease, but the relationship between them is not fully understood.
  • In a study using PS19 mice, early-onset hyperarousal and selective sleep disruption were observed, with significant memory decline due to chronic sleep disruption occurring in males.
  • Despite earlier hyperarousal in females, they showed more resilience in cognitive decline compared to males, indicating potential sex-specific differences in the effects of sleep disruption on cognitive health.
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  • Sleep disruption is common in aging and neurodegenerative diseases like Alzheimer's, contributing to cognitive decline and AD progression, making better sleep treatments necessary.
  • Current sleep medications can increase the risk of AD, prompting researchers to explore alternatives like the endocannabinoid system and fatty acid amide hydrolase (FAAH) as potential sleep aids.
  • While inhibiting FAAH showed short-term benefits for sleep in a model of Tauopathy, knockout studies indicated that completely disabling FAAH may not be beneficial for overall sleep health or cognitive function.
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  • Glyphosate, a common herbicide, targets the shikimate pathway in plants and affects gut microbiota, which can potentially disrupt the gut-brain axis and lead to neurological issues.
  • In a study, mice were exposed to two different doses of glyphosate over time; neurobehavioral changes were minimal, but significant alterations in fecal metabolites were observed, especially in aromatic amino acids at higher doses.
  • The research concluded that even at high levels of glyphosate, there was little evidence of impairment in the gut-brain axis, suggesting that neurotoxicity and gut microbiota changes may not be as pronounced as initially thought.
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  • TDP-43 proteinopathies, such as frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS), are neurodegenerative diseases where the protein TDP-43 misfolds and disrupts neuronal function.
  • Researchers created models that mimic sporadic TDP-43 proteinopathy, showing how acetylation at lysine 145 impairs TDP-43's ability to bind RNA and leads to gene mis-regulation.
  • Results indicate that this acetylation triggers harmful changes in neurons, evidenced by cognitive decline and altered gene expression related to synaptic function, mirroring characteristics seen in human FTLD cases.
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Neurodevelopmental disorders (NDDs) are complex conditions characterized by heterogeneous clinical profiles and symptoms that arise in infancy and childhood. NDDs are often attributed to a complicated interaction between genetic risk and environmental factors, suggesting a need for preclinical models reflecting the combined impact of heritable susceptibility and environmental effects. A notable advantage of "two-hit" models is the power to reveal underlying vulnerability that may not be detected in studies employing only genetic or environmental alterations.

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  • Sleep disruption is linked to neurodegenerative diseases like Alzheimer's, where impaired synaptic processes may contribute to cognitive decline, particularly through Tau protein aggregation.
  • A study using transgenic mice revealed that PS19 mice experience early loss of sleep during the dark phase, with females showing symptoms earlier than males.
  • Although sleep disruption did not increase Tau pathology in the brain, chronic sleep loss was found to worsen spatial memory decline specifically in male mice.
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  • Acetylcholine (ACh) signaling changes have been linked to several neurological diseases, and ACh neurons in the brain also release GABA, but the role of GABA in ACh signaling is not fully understood.
  • This study aimed to explore how the elimination of GABA co-transmission from ACh neurons impacted mouse behaviors, using genetically modified mice that specifically lacked the ability to co-release GABA.
  • The results showed that while basic functions like sociability and motor skills remained unchanged, the loss of GABA co-transmission significantly impaired social, spatial, and fear memory, indicating that ACh/GABA interactions are important for higher cognitive processes.
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  • Behavioral phenotyping in neonatal mice helps researchers study how early changes in brain development relate to human neurodevelopmental disorders.
  • This chapter outlines a testing method that assesses mice behavior while reducing stress for the pups and their mothers.
  • Testing starts when mice are 6-8 days old and includes various evaluations up to 20-21 days, focusing on different behavioral traits like movement and reflexes.
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  • Patients with autism spectrum disorder (ASD) experience significant sleep disruptions early in life, which may have lasting developmental effects; researchers investigated this in mice with a SHANK3 gene mutation linked to ASD.
  • They recorded sleep patterns in Shank3 mutated mice and wild-type siblings, exposing them to early life sleep disruption and comparing various behavioral outcomes later in adulthood.
  • Results showed that Shank3 mice slept less and exhibited distinct behavioral changes based on sex and early life sleep disruption, whereas wild-type mice appeared resilient, highlighting potential long-term consequences of sleep issues in genetically vulnerable populations.
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  • * A set of key genes, including Usp11 and Wars2, was found to be altered in these mice at different ages, with CHD8 shown to directly interact with their genetic regions.
  • * Older Chd8 mice exposed to DM also exhibited more severe symptoms and changes in gene expression related to vascular health, highlighting how genetic factors and environmental influences together shape autism-related traits throughout development.
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  • SPTBN1 gene encodes βII-spectrin, crucial for forming networks at plasma membranes, and its deficiency in mice leads to significant neurodevelopmental issues.
  • Heterozygous variants of SPTBN1 were identified in 29 individuals exhibiting a range of developmental challenges, including intellectual disabilities, language delays, and autistic features.
  • These variants weaken βII-spectrin stability and disrupt cellular organization, establishing SPTBN1 as a key contributor to certain neurodevelopmental syndromes.
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  • The apelinergic system, involving the G-protein-coupled receptor APLNR and its ligands apelin and ELABELA/TODDLER, plays a crucial role in development and maintaining physiological balance.
  • Research using Aplnr knockout mice reveals significant sensory and behavioral changes, particularly affecting fear responses in males without altering baseline anxiety levels.
  • These findings support the potential of targeting APLNR for therapeutic purposes in conditions like PTSD, especially since prior studies indicated that apelin can reduce fear and anxiety responses in rodent models.
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Chemokines such as chemokine (C-C motif) ligand 2 (CCL2) play a role in several behaviors, including anxiety-like behavior, but whether neurons are an important source of CCL2 for behavior and how neuronal CCL2 may work to affect behavior are still debated. When a herpes simplex virus (HSV) vector was used to knockdown CCL2 mRNA in neurons of the central nucleus of the amygdala (CeA) in rats experiencing multiple withdrawals from low dose ethanol, anxiety-like behavior appeared in the social interaction task. To examine this finding further Fractalkine (CX3CL1), a chemokine that is often found to have an opposing function to CCL2 was measured in these rats.

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Background: Chronic ethanol (EtOH) exposure induces neurobehavioral maladaptations in the brain though the precise changes have not been fully explored. The central nucleus of the amygdala (CEA) regulates anxiety-like behavior induced by withdrawal from chronic intermittent EtOH (CIE) exposure, and the arginine vasopressin (AVP) system within the CEA regulates many anxiety-like behaviors. Thus, adaptations occur in the CEA AVP system due to chronic EtOH exposure, which lead to anxiety-like behaviors in rats.

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Background: Arginine vasopressin (VP) has been implicated in a number of neuropsychiatric disorders with an emphasis on situations where stress increased the severity of the disorder. Based on this hypothesized role for VP in neuropsychiatric disorders, much research is currently being undertaken in humans and animals to test VP as a target for treatment of a number of these disorders including alcohol abuse.

Objectives: To provide a summary of the literature regarding the role of VP in alcohol- and stress-related behaviors including the use of drugs that target VP in clinical trials.

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Patients with depression and rodent models of depression show increased cytokines and activated microglia. Fawn Hooded (FH/Wjd) rats have long been used as a model of depression based on their depressive-like behaviors, high basal corticosterone levels and altered serotonergic levels, but little is known about the neuroimmune function in this model. To test whether depressive-like behaviors relate to dysfunction of the neuroimmune system, depressive-like behaviors in the forced swim test (FST) and corticosterone (CORT) response to the swim test were compared in male Fawn Hooded versus Wistar rats, and cytokine levels in plasma and brain and plasma CORT in response to lipopolysaccharide (LPS, an endotoxin that activates the neuroimmune system) or 1 h restraint were measured.

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Neuroimmune cytokines are increased with alcohol withdrawal and may mediate clinical responses associated with alcoholism. Because minocycline regulates the level of cytokines, it has been suggested as a therapeutic for disorders associated with alcohol. Male Wistar rats were exposed to chronic intermittent alcohol (CIA) comprising three 5-day cycles of ethanol liquid diet separated by 2 days of withdrawal.

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Rationale: Behavioral and neuroimmune vulnerability to withdrawal from chronic alcohol varies with age. The relation of anxiety-like behavior to amygdalar CCL2 responses following stress after withdrawal from chronic intermittent alcohol (CIA) was investigated in adolescent and adult rats.

Methods: Adolescent and adult Wistar rats were exposed to CIA (three 5-day blocks of dietary alcohol separated by 2 days of withdrawal) at concentrations that created similar blood alcohol levels across age.

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Stress is a strong risk factor in alcoholic relapse and may exert effects that mimic aspects of chronic alcohol exposure on neurobiological systems. With the neuroimmune system becoming a prominent focus in the study of the neurobiological consequences of stress, as well as chronic alcohol exposure proving to be a valuable focus in this regard, the present study sought to compare the effects of stress and chronic ethanol exposure on induction of components of the neuroimmune system. Rats were exposed to either 1 h exposure to a mild stressor (restraint) or exposure to withdrawal from 15 days of chronic alcohol exposure (i.

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The neurodevelopmental fetal alcohol spectrum disorder (FASD) is characterized by cognitive and behavioral deficits in the offspring. Conferring the deficits to the next generation would increase overall FASD disease burden and prevention of this transmission could be highly significant. Prior studies showed the reversal of these behavioral deficits by low dose thyroxine (T4) supplementation to the ethanol-consuming mothers.

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Background: The role of neuroimmune activation in withdrawal from chronic alcohol (ethanol) has been established in both adolescent and adult models, but direct comparisons across age are sparse. Studies need to elucidate age-dependent neuroimmune effects of alcohol and to focus research attention on age-dependent mechanisms and outcomes.

Methods: Adult and adolescent rats from 2 commonly used strains, Wistar and Sprague Dawley (SD), were maintained on continuous 7%, 5.

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Fetal alcohol spectrum disorder (FASD) presents a collection of symptoms representing physiological and behavioral phenotypes caused by maternal alcohol consumption. Symptom severity is modified by genetic differences in fetal susceptibility and resistance as well as maternal genetic factors such as maternal alcohol sensitivity. Animal models demonstrate that both maternal and paternal genetics contribute to the variation in the fetus' vulnerability to alcohol exposure.

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Insulin-like growth factor 2 (Igf2) regulates development, memory and adult neurogenesis in the hippocampus. Calorie restriction (CR) is known to modulate non-neuronal Igf2 expression intergenerationally, but its effect has not been evaluated on brain Igf2. Here, Sprague-Dawley (S) dams underwent moderate CR between gestational days 8-21.

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Consequences of prenatal exposure to ethanol (E) include morphological, physiological, and cognitive deficits and are collectively classified as fetal alcohol spectrum disorders. Adult prenatal E exposed offspring show insulin resistance, and given that in utero hyperglycemic environment can cause metabolic disorders in subsequent generations; we investigated the effects of grandmaternal E on functional glucose and insulin responses of the second generation. Sprague-Dawley (S) rat dams, mated with S males, received E-containing liquid diet and two different control diets between gestational days 8 and 20.

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Social behavior dysfunction is a symptomatic element of schizophrenia and autism spectrum disorder (ASD). Although altered activities in numerous brain regions are associated with defective social cognition and perception, the causative relationship between these altered activities and social cognition and perception-and their genetic underpinnings-are not known in humans. To address these issues, we took advantage of the link between hemizygous deletion of human chromosome 22q11.

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