Age-matched Non-transgenic Mice Research Articles

Sex-Specific Early Retinal Dysfunction in Mutant TDP-43 Transgenic Mice.

Increasing evidence has highlighted retinal impairments in neurodegenerative diseases. Dominant mutations in TAR DNA-binding protein 43 (TDP-43) cause amyotrophic lateral sclerosis (ALS), and the accumulation of TDP-43 in the cytoplasm is a pathological hallmark of ALS, frontotemporal dementia (FTD), and many other neurodegenerative diseases. While homozygous transgenic mice expressing the disease-causing human TDP-43 M337V mutant (TDP-43M337V mice) experience premature death, hemizygous TDP-43M337V mice do not suffer sudden death, but they exhibit age-dependent motor-coordinative and cognitive deficits. This study aims to leverage the hemizygous TDP-43M337V mice as a valuable ALS/FTD disease model for the assessment also of retinal changes during the disease progression. We evaluated the retinal function of young TDP-43M337V mice by full field electroretinogram (ERG) recordings. At 3-4 months of age, well before the onset of brain dysfunction at 8 months, the ERG responses were notably impaired in the retinas of young female TDP-43M337V mice in contrast to their male counterparts and age-matched non-transgenic mice. Mitochondria have been implicated as critical targets of TDP-43. Further investigation revealed that significant changes in the key regulators of mitochondrial dynamics and bioenergetics were only observed in the retinas of young female TDP-43M337V mice, while these alterations were not present in the brains of either gender. Together our findings suggest a sex-specific vulnerability within the retina in the early disease stage, and highlight the importance of retinal changes and mitochondrial markers as potential early diagnostic indicators for ALS, FTD, and other TDP-43 related neurodegenerative conditions.

Upregulation of sFRP1 Is More Profound in Female than Male 5xFAD Mice and Positively Associated with Amyloid Pathology.

The prevalence of Alzheimer's disease is greater in women, but the underlying mechanisms remain to be elucidated. We herein demonstrated that α-secretase ADAM10 was downregulated and ADAM10 inhibitor sFRP1 was upregulated in 5xFAD mice. While there were no sex effects on ADAM10 protein and sFRP1 mRNA levels, female 5xFAD and age-matched non-transgenic mice exhibited higher levels of sFRP1 protein than corresponding male mice. Importantly, female 5xFAD mice accumulated more Aβ than males, and sFRP1 protein levels were positively associated with Aβ42 levels in 5xFAD mice. Our study suggests that sFRP1 is associated with amyloid pathology in a sex-dependent manner.

IL-1β and TNF-α play an important role in modulating the risk of periodontitis and Alzheimer’s disease

BackgroundSystemic activation of the immune system can exert detrimental effects on the central nervous system. Periodontitis, a chronic disease of the oral cavity, is a common source of systemic inflammation. Neuroinflammation might be a result of this to accelerate progressive deterioration of neuronal functions during aging or exacerbate pre-existing neurodegenerative diseases, such as Alzheimer’s disease. With advancing age, the progressive increase in the body’s pro-inflammatory status favors the state of vulnerability to both periodontitis and Alzheimer’s disease. In the present study, we sought to delineate the roles of cytokines in the pathogenesis of both diseases.MethodsTo examine the impacts of periodontitis on the onset and progression of Alzheimer’s disease, 6-month-old female 3 × Tg-AD mice and their age-matched non-transgenic mice were employed. Periodontitis was induced using two different experimental models: heat-killed bacterial-induced periodontitis and ligature-induced periodontitis. To delineate the roles of pro-inflammatory cytokines in the pathogenesis of periodontitis and Alzheimer’s disease, interleukin 1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) were also injected into the buccal mandibular vestibule of mice.ResultsHere, we show that IL-1β and TNF-α were two of the most important and earliest cytokines upregulated upon periodontal infection. The systemic upregulation of these two cytokines promoted a pro-inflammatory environment in the brain contributing to the development of Alzheimer’s disease-like pathology and cognitive dysfunctions. Periodontitis-induced systemic inflammation also enhanced brain inflammatory responses and subsequently exacerbated Alzheimer’s disease pathology and cognitive impairment in 3 × Tg-AD mice. The role of inflammation in connecting periodontitis to Alzheimer’s disease was further affirmed in the conventional magnetization transfer experiment in which increased glial responses resulting from periodontitis led to decreased magnetization transfer ratios in the brain of 3 × Tg-AD mice.ConclusionsSystemic inflammation resulting from periodontitis contributed to the development of Alzheimer’s disease tau pathology and subsequently led to cognitive decline in non-transgenic mice. It also potentiated Alzheimer’s disease pathological features and exacerbated impairment of cognitive function in 3 × Tg-AD mice. Taken together, this study provides convincing evidence that systemic inflammation serves as a connecting link between periodontitis and Alzheimer’s disease.

Therapeutic potential of iron modulating drugs in a mouse model of multiple system atrophy

Multiple System Atrophy (MSA) is a rare neurodegenerative synucleinopathy which leads to severe disability followed by death within 6–9 years of symptom onset. There is compelling evidence suggesting that biological trace metals like iron and copper play an important role in synucleinopathies like Parkinson's disease and removing excess brain iron using chelators could slow down the disease progression. In human MSA, there is evidence of increased iron in affected brain regions, but role of iron and therapeutic efficacy of iron-lowering drugs in pre-clinical models of MSA have not been studied.We studied age-related changes in iron metabolism in different brain regions of the PLP-αsyn mice and tested whether iron-lowering drugs could alleviate disease phenotype in aged PLP-αsyn mice. Iron content, iron-ferritin association, ferritin protein levels and copper-ceruloplasmin association were measured in prefrontal cortex, putamen, substantia nigra and cerebellum of 3, 8, and 20-month-old PLP-αsyn and age-matched non-transgenic mice. Moreover, 12-month-old PLP-αsyn mice were administered deferiprone or ceruloplasmin or vehicle for 2 months. At the end of treatment period, motor testing and stereological analyses were performed.We found iron accumulation and perturbed iron-ferritin interaction in substantia nigra, putamen and cerebellum of aged PLP-αsyn mice. Furthermore, we found significant reduction in ceruloplasmin-bound copper in substantia nigra and cerebellum of the PLP-αsyn mice. Both deferiprone and ceruloplasmin prevented decline in motor performance in aged PLP-αsyn mice and were associated with higher neuronal survival and reduced density of α-synuclein aggregates in substantia nigra.This is the first study to report brain iron accumulation in a mouse model of MSA. Our results indicate that elevated iron in MSA mice may result from ceruloplasmin dysfunction and provide evidence that targeting iron in MSA could be a viable therapeutic option.

Atrophy of lacunosum moleculare layer is important for learning and memory in APP/PS1 transgenic mice

Changes in the hippocampus are closely associated with learning and memory in Alzheimer's disease; however, it is not clear which morphological and cellular and subcellular changes are essential for learning and memory. Here, we accurately quantitatively studied the hippocampal microstructure changes in Alzheimer's disease model mice and analyzed the relationship between the hippocampal microstructure changes and learning and memory. Ten-month-old male APP/PS1 transgenic mice and age-matched nontransgenic littermate mice were randomly selected. The spatial learning and memory abilities were assessed using the Morris water maze. The volumes of each layer and numbers of neurons, dendritic spines and oligodendrocytes in the hippocampal subregions were investigated using unbiased stereological techniques. The APP/PS1 transgenic mice showed a decline in hippocampus-dependent spatial learning and memory abilities, smaller volumes of each layer (other than stratum radiatum) and fewer numbers of neurons, dendritic spine synapses and mature oligodendrocytes in the hippocampal subregions than nontransgenic mice. In particular, the decline of spatial learning ability was significantly correlated with the atrophy of lacunosum moleculare layer (LMol) and the decrease of hippocampal neurons and mature oligodendrocytes rather than dendritic spines. The CA1-3 fields (including LMol) atrophy was significantly correlated with the decrease both of neurons, dendritic spines and mature oligodendrocytes. However, the dentate gyrus atrophy was significantly correlated with the decrease of neurons and mature oligodendrocytes rather than dendritic spines. The loss of neurons, dendritic spines synapses and mature oligodendrocytes together caused the LMol atrophy and then led to a decline in hippocampus-dependent spatial learning ability in mice with Alzheimer's disease.

Alterations in the Gut-Microbial-Inflammasome-Brain Axis in a Mouse Model of Alzheimer's Disease.

Alzheimer’s disease (AD), a progressive neurodegenerative disorder characterized by memory loss and cognitive decline, is a major cause of death and disability among the older population. Despite decades of scientific research, the underlying etiological triggers are unknown. Recent studies suggested that gut microbiota can influence AD progression; however, potential mechanisms linking the gut microbiota with AD pathogenesis remain obscure. In the present study, we provided a potential mechanistic link between dysbiotic gut microbiota and neuroinflammation associated with AD progression. Using a mouse model of AD, we discovered that unfavorable gut microbiota are correlated with abnormally elevated expression of gut NLRP3 and lead to peripheral inflammasome activation, which in turn exacerbates AD-associated neuroinflammation. To this end, we observe significantly altered gut microbiota compositions in young and old 5xFAD mice compared to age-matched non-transgenic mice. Moreover, 5xFAD mice demonstrated compromised gut barrier function as evident from the loss of tight junction and adherens junction proteins compared to non-transgenic mice. Concurrently, we observed increased expression of NLRP3 inflammasome and IL-1β production in the 5xFAD gut. Consistent with our hypothesis, increased gut–microbial–inflammasome activation is positively correlated with enhanced astrogliosis and microglial activation, along with higher expression of NLRP3 inflammasome and IL-1β production in the brains of 5xFAD mice. These data indicate that the elevated expression of gut–microbial–inflammasome components may be an important trigger for subsequent downstream activation of inflammatory and potentially cytotoxic mediators, and gastrointestinal NLRP3 may promote NLRP3 inflammasome-mediated neuroinflammation. Thus, modulation of the gut microbiota may be a potential strategy for the treatment of AD-related neurological disorders in genetically susceptible hosts.

0418 Effect of Acute Administration of DORA-12 on Sleep Impairment in the Aged PS19 Mouse Model of Tauopathy

Abstract Introduction Aged PS19 mice (MAPT P301S), a mouse model of tauopathy and neurodegeneration, display reduced NREM and REM sleep starting around 8-9 months before death around 12 months. Here, we tested the acute effect of a dual orexin receptor antagonist (DORA-12) on sleep in 11 mice (5 male, 6 female) at 10.3±1.8 months. Methods Two consecutive 24-hour recordings (12/12hr L:D cycle) were scored semi-automatically for non-REM sleep, REM sleep, and wake in mice implanted with EEG/EMG. Mice were treated with either vehicle (day 1) or 100mg/kg of DORA-12 (day 2) by oral gavage at both ZT0 and ZT9. Results After the first dose at ZT0, both latency to the first NREM sleep episode (paired t-test p=0.002) and to the first REM sleep episode (paired t-test p=0.005) was significantly shorter with DORA-12 (NREM: 20.8±17.8 min.; REM: 23.5±21.2 min.) compared to vehicle (NREM: 49.2±22.3 min.; REM: 127.0±93.3 min.). There was no difference in NREM or REM sleep latency observed after the second dose at ZT9. DORA-12 treatment increased NREM duration across the 24hr period (DORA-12: 664±52 min.; Veh: 601±54 min., paired t-test p=0.007) and also after the 2nd dose (DORA-12: 311±65 min.; Veh: 263±84 min., paired t-test p=0.009). DORA-12 treatment also increased REM duration across 24hrs (DORA-12: 61±30 min.; Veh: 48±29 min., paired t-test p=0.014) but not after the 2nd dose alone (DORA-12: 22±14 min.; Veh: 20±15 min., paired t-test p=0.388). Notably in both vehicle and DORA-12 conditions, we observed apparent dream enactment behavior including mastication, paw grasp, and fore limb extension during REM in 3 of 11 PS19 mice (all male), not typically observed in younger PS19 or age-matched non-transgenic mice, suggestive of a possible REM behavior disorder (RBD) phenotype. Wake-like behaviors occurred during theta-dominant EEG but with an EMG amplitude >4SD the preceding NREM sleep baseline for at least > 1sec. Conclusion In aged PS19 mice, DORA-12 was found to decrease the latency to NREM and REM after the first dose while also increasing NREM and REM duration across the entire 24hr recording period. We also capture a heretofore undescribed RBD-like phenotype in aged PS19 tauopathy mice. Support Merck MISP

Quantitative study of the capillaries within the white matter of the Tg2576 mouse model of Alzheimer's disease.

IntroductionTo quantitatively investigate the capillaries within the white matter of Tg2576 Alzheimer's disease (AD) transgenic mice during the early stage.MethodsIn the current study, 10‐month‐old male Tg2576 AD mice were used as the early‐stage AD group and age‐matched nontransgenic littermate mice were used as the wild‐type group. Then, the Morris water maze was used to examine the spatial learning and memory abilities of the mice in both groups, and unbiased stereological methods were used to accurately quantify the volume of white matter and the parameters of the capillaries within the white matter, such as the total length, total volume, and total surface area of capillaries.ResultsThe Morris water maze performance of the Tg2576 group was worse than that of the wild‐type group, while the white matter volume did not significantly differ between the wild‐type group and the Tg2576 group. The total length, total volume, and total surface area of the capillaries within the white matter of the Tg2576 group were significantly decreased compared to those of the wild‐type group.ConclusionsThe current study provide structural basis for understanding the pathological changes of the early stage of AD and cognitive decline in AD might be associated with changes in the white matter capillaries. Capillaries within the white matter might, thus, serve as a valid target for the prevention and treatment of early‐stage AD.

Endocannabinoid and Muscarinic Signaling Crosstalk in the 3xTg-AD Mouse Model of Alzheimer's Disease.

The endocannabinoid system, which modulates emotional learning and memory through CB1 receptors, has been found to be deregulated in Alzheimer's disease (AD). AD is characterized by a progressive decline in memory associated with selective impairment of cholinergic neurotransmission. The functional interplay of endocannabinoid and muscarinic signaling was analyzed in seven-month-old 3xTg-AD mice following the evaluation of learning and memory of an aversive stimulus. Neurochemical correlates were simultaneously studied with both receptor and functional autoradiography for CB1 and muscarinic receptors, and regulations at the cellular level were depicted by immunofluorescence. 3xTg-AD mice exhibited increased acquisition latencies and impaired memory retention compared to age-matched non-transgenic mice. Neurochemical analyses showed changes in CB1 receptor density and functional coupling of CB1 and muscarinic receptors to Gi/o proteins in several brain areas, highlighting that observed in the basolateral amygdala. The subchronic (seven days) stimulation of the endocannabinoid system following repeated WIN55,212-2 (1 mg/kg) or JZL184 (8 mg/kg) administration induced a CB1 receptor downregulation and CB1-mediated signaling desensitization, normalizing acquisition latencies to control levels. However, the observed modulation of cholinergic neurotransmission in limbic areas did not modify learning and memory outcomes. A CB1 receptor-mediated decrease of GABAergic tone in the basolateral amygdala may be controlling the limbic component of learning and memory in 3xTg-AD mice. CB1 receptor desensitization may be a plausible strategy to improve behavior alterations associated with genetic risk factors for developing AD.

Reduced cooperativity of voltage-gated sodium channels in the hippocampal interneurons of an aged mouse model of Alzheimer's disease.

Beta amyloid (A[Formula: see text] ) associated with Alzheimer's disease (AD) leads to abnormal behavior in inhibitory neurons, resulting in hyperactive neuronal networks, epileptiform behavior, disrupted gamma rhythms, and aberrant synaptic plasticity. Previously, we used a dual modeling-experimental approach to explain several observations, including failure to reliably produce action potentials (APs), smaller AP amplitudes, higher resting membrane potential, and higher membrane depolarization in response to a range of stimuli in hippocampal inhibitory neurons from 12- to 16-month-old female AP Pswe/PSEN1DeltaE9 (APdE9) AD mice as compared to age-matched non-transgenic (NTG) mice. Our experimental results also showed that AP initiation in interneurons from APdE9 mice are significantly different from that of NTG mice. APs in interneurons from NTG mice are characterized by abrupt onset and an upstroke that is much steeper and occurs with larger variability as compared to cells from APdE9 mice. The phase plot (the rate of change of membrane potential versus the instantaneous membrane potential) of APs produced by interneurons from APdE9 mice shows a biphasic behavior, whereas that from NTG mice shows a monophasic behavior. Here we show that using the classic Hodgkin-Huxley (HH) formalism for the gating of voltage-gated sodium channels (VGSCs) in a single-compartment neuron, we cannot reproduce these features, and a model that takes into account a cooperative activation of VGSCs is needed. We also argue that considering a realistic multi-compartment neuron where the kinetics of VGSC is modeled by HH formalism, as done in the past, would not explain our observations when APs from both NTG and APdE9 mice are considered simultaneously. Wefurther show that VGSCs in interneurons from APdE9 mice exhibit significantly lower cooperativity in their activation as compared to those from NTG mice.

Hippocampal mutant APP and amyloid beta-induced cognitive decline, dendritic spine loss, defective autophagy, mitophagy and mitochondrial abnormalities in a mouse model of Alzheimer's disease.

The purpose of our study was to determine the toxic effects of hippocampal mutant APP and amyloid beta (Aβ) in 12-month-old APP transgenic mice. Using rotarod and Morris water maze tests, immunoblotting and immunofluorescence, Golgi-cox staining and transmission electron microscopy, we assessed cognitive behavior, protein levels of synaptic, autophagy, mitophagy, mitochondrial dynamics, biogenesis, dendritic protein MAP2 and quantified dendritic spines and mitochondrial number and length in 12-month-old APP mice that express Swedish mutation. Mitochondrial function was assessed by measuring the levels of hydrogen peroxide, lipid peroxidation, cytochrome c oxidase activity and mitochondrial ATP. Morris water maze and rotarod tests revealed that hippocampal learning and memory and motor learning and coordination were impaired in APP mice relative to wild-type (WT) mice. Increased levels of mitochondrial fission proteins, Drp1 and Fis1 and decreased levels of fusion (Mfn1, Mfn2 and Opa1) biogenesis (PGC1α, NRF1, NRF2 and TFAM), autophagy (ATG5 and LC3BI, LC3BII), mitophagy (PINK1 and TERT), synaptic (synaptophysin and PSD95) and dendritic (MAP2) proteins were found in 12-month-old APP mice relative to age-matched non-transgenic WT mice. Golgi-cox staining analysis revealed that dendritic spines are significantly reduced. Transmission electron microscopy revealed significantly increased mitochondrial numbers and reduced mitochondrial length in APP mice. These findings suggest that hippocampal accumulation of mutant APP and Aβ is responsible for abnormal mitochondrial dynamics and defective biogenesis, reduced MAP2, autophagy, mitophagy and synaptic proteins and reduced dendritic spines and hippocampal-based learning and memory impairments, and mitochondrial structural and functional changes in 12-month-old APP mice.

Motor-Coordinative and Cognitive Dysfunction Caused by Mutant TDP-43 Could Be Reversed by Inhibiting Its Mitochondrial Localization

Dominant missense mutations in TAR DNA-binding protein43 (TDP-43) cause amyotrophic lateral sclerosis (ALS), and the cytoplasmic accumulation of TDP-43 represents a pathological hallmark in ALS and frontotemporal lobar degeneration (FTD). Behavioral investigation of the transgenic mouse model expressing the disease-causing human TDP-43 M337Vmutant (TDP-43M337V mice) is encumbered by premature death in homozygous transgenic mice and a reported lack of phenotype assessed by tail elevation and footprint in hemizygous transgenic mice. Here, using a battery of motor-coordinative and cognitive tests, we report robust motor-coordinative and cognitive deficits in hemizygous TDP-43M337V mice by 8months of age. After 12months of age, cortical neurons are significantly affected by the mild expression of mutant TDP-43, characterized by cytoplasmic TDP-43 mislocalization, mitochondrial dysfunction, and neuronal loss. Compared with age-matched non-transgenic mice, TDP-43M337V mice demonstrate a similar expression of total TDP-43 but higher levels of TDP-43 in mitochondria. Interestingly, a TDP-43 mitochondrial localization inhibitory peptide abolishes cytoplasmic TDP-43 accumulation, restores mitochondrial function, prevents neuronal loss, and alleviates motor-coordinative and cognitive deficits in adult hemizygous TDP-43M337V mice. Thus, this study suggests hemizygous TDP-43M337V mice as a useful animal model to study TDP-43 toxicity and further consolidates mitochondrial TDP-43 as a novel therapeutic target for TDP-43-linked neurodegenerative diseases.

Activity of muscarinic, galanin and cannabinoid receptors in the prodromal and advanced stages in the triple transgenic mice model of Alzheimer’s disease

Neurochemical alterations in Alzheimer’s disease (AD) include cholinergic neuronal loss in the nucleus basalis of Meynert (nbM) and a decrease in densities of the M2 muscarinic receptor subtype in areas related to learning and memory. Neuromodulators present in the cholinergic pathways, such as neuropeptides and neurolipids, control these cognitive processes and have become targets of research in order to understand and treat the pathophysiological and clinical stages of the disease. This is the case of the endocannabinoid and galaninergic systems, which have been found to be up-regulated in AD, and could therefore have a neuroprotective role. In the present study, the functional coupling of Gi/o protein-coupled receptors to GalR1, and the CB1 receptor subtype for endocannabinoids were analyzed in the 3xTg-AD mice model of AD. In addition, the activity mediated by Gi/o protein-coupled M2/4 muscarinic receptor subtypes was also analyzed in brain areas involved in anxiety and cognition. Thus, male mice were studied at 4 and 15months of age (prodromal and advanced stages, respectively) and compared to age-matched non-transgenic (NTg) mice (adult and old, respectively). In 4-month-old 3xTg-AD mice, the [35S]GTPγS binding stimulated by galanin was significantly increased in the hypothalamus, but a decrease of functional M2/4 receptors was observed in the posterior amygdala. The CB1 cannabinoid receptor activity was up-regulated in the anterior thalamus at that age. In 15-month-old 3xTg-AD mice, muscarinic receptor activity was found to be increased in motor cortex, while CB1 activity was decreased in nbM. No changes were found in GalR1-mediated activity at this age. Our results provide further evidence of the relevance of limbic areas in the prodromal stage of AD, the profile of which is characterized by anxiety. The up-regulation of galaninergic and endocannabinoid systems support the hypothesis of their neuroprotective roles, and these are established prior to the onset of clear clinical cognitive symptoms of the disease.

Abstract 2800: Dietary black raspberries (BRBs) inhibit tumor progression in PTEN-deficient mouse model of prostate cancer

Abstract Black raspberries (BRBs) a natural food demonstrated to have anti-oxidant, anti-inflammatory and anti-cancer activities,have been shown to inhibit oral, esophageal, mammary gland and colon cancers in rodents. Several human trials have been completed to date to assess the efficacy of BRB formulations for cancer prevention. However, the chemopreventive potential of BRBs against prostate cancer, the most commonly diagnosed malignancy and the second leading cause of death among men in the United States, is yet to be reported. Among the murine models, PTEN-mutant mice develop tumors in situ that faithfully mimic the intratumor heterogeneity observed during the progression of human prostate cancer. Therefore, we utilized this clinically relevant PTEN-mutant mouse model to evaluate the chemopreventive potential of BRBs against prostate cancer. Genotyped 5-week-old male PTEN-mutant mice, randomly assigned to control and treatment groups (n = 12 mice/group), were fed AIN-93G diet (control) or AIN-93G diet supplemented with BRBs (5 or 10%) for 23 weeks. Age-matched non-transgenic mice (wild-type) served as experimental controls (n = 6). Animal weight and food consumption were measured during the treatment period, and the mice were euthanized at 28 weeks of age. Prostate tissues were harvested, weighed and fixed in 10% formalin for histopathological analysis. Histological, cell proliferation (Ki-67 staining) and apoptosis (TUNEL) analyses were performed to determine the chemopreventive potential of BRBs. PTEN-mutant mice fed control or BRB (5 or 10%) diets had steady body weight gain, 16 to 18 g during the 23-week treatment. BRB diets were well tolerated as none of the animals fed BRBs exhibited any observable toxicity. PTEN-mutant mice (control) had increased prostate weight (ave. = 248 mg) relative to wild-type mouse prostate (ave. = 90 mg), and 5 and 10% BRB diets significantly (p<0.01) decreased the prostate weights to ave. = 116 and 162 mg, respectively, compared to control. In addition, 5% BRBs significantly (p<0.05) reduced the prostate weights compared to 10% BRBs. Histological examination of dorsolateral prostate (DLP) revealed that 98% of PTEN-mutant mice fed control diet developed invasive adenocarcinomas, whereas both 5 and 10% BRB diets significantly reduced tumor incidence and the progression of PIN lesions to invasive adenocarcinomas by 64% (p<0.0001) and 43% (p<0.001), respectively. Interestingly, 5% BRBs appear to be more effective than 10% BRBs (p<0.01). Both 5 and 10% BRBs significantly reduced tumor cell proliferation rates and induced apoptosis, p<0.0001 and p<0.001, respectively. Furthermore, mice fed both 5 and 10% BRBs contained more normal appearing prostates (free from PIN lesions and adenocarcinomas), when compared to control mice (54 and 33% compared to 3%, respectively). In conclusion, our data indicate that BRBs may have significant potential for prostate cancer prevention and/or treatment. Citation Format: Narayanan K. Narayanan, Gary D. Stoner, Daniel S. Peiffer, Karen Galdanes, Eric Larios, Alu Mark, Lisa Maziniski, Luis Chiriboga, Maarten C. Bosland. Dietary black raspberries (BRBs) inhibit tumor progression in PTEN-deficient mouse model of prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2800. doi:10.1158/1538-7445.AM2015-2800

Tail-flick test response in 3 × Tg-AD mice at early and advanced stages of disease

Despite the impact of pain in cognitive dysfunctions and affective disorders has been largely studied, the research that examines pain dimensions in cognitive impairment or dementia is still scarce. In patients with Alzheimer’s disease (AD) and related dementias, management of pain is challenging. While the sensory-discriminative dimension of pain is preserved, the cognitive-evaluative and the affective-motivational pain dimensions are affected. Due to the complexity of the disease and the poor self-reports, pain is underdiagnosed and undertreated. In confluence with an impaired thermoregulatory behavior, the patients’ ability to confront environmental stressors such as cold temperature can put them at risk of fatal accidental hypothermia. Here, 3xTg-AD mice demonstrate that the sensorial-discriminative threshold to a noxious cold stimulus, as measured by the latency of tail-flicking, was preserved at early and advances stages of disease (7 and 11 month-old, respectively) as compared to age-matched (adulthood and middle aged, respectively) non-transgenic mice (NTg). In both genotypes, the sensory deterioration and poor thermoregulatory behavior associated to age was observed as an increase of tail-flick response and poor sensorimotor performance. At both stages studied, 3xTg-AD mice exhibited BPSD (Behavioral and Psychological Symptoms of Dementia)-like alterations in the corner, open-field, dark-light box and the T-maze tests. In the adult NTg mice, this nociceptive withdrawal response was correlated with copying with stress-related behaviors. This integrative behavioral profile was lost in both groups of 3xTg-AD mice and middle aged controls, suggesting derangements in their subjacent networks and the complex interplay between the pain dimensions in the elderly with dementia.

Marble-burying is enhanced in 3xTg-AD mice, can be reversed by risperidone and it is modulable by handling

Translational research on behavioural and psychological symptoms of dementia (BPSD) is relevant to the study the neuropsychiatric symptoms that strongly affect the quality of life of the human Alzheimer’s disease (AD) patient and caregivers, frequently leading to early institutionalization. Among the ethological behavioural tests for rodents, marble burying is considered to model the spectrum of anxiety, psychotic and obsessive–compulsive like symptoms. The present work was aimed to study the behavioural interactions of 12 month-old male 3xTg-AD mice with small objects using the marble-burying test, as compared to the response elicited in age-matched non-transgenic (NTg) mice. The distinction of the classical ‘number of buried marbles’ but also those left ‘intact’ and those ‘changed’ of position of marbles or partially buried (the transitional level of interaction) provided new insights into the modelling of BPSD-like alterations in this AD model. The analysis revealed genotype differences in the behavioural patterns and predominant behaviors. In the NTg mice, predominance was shown in the ‘changed or partially buried’, while interactions with marble were enhanced in 3xTg-AD mice resulting in an increase of marble burying. Besides, genotype-dependent meaningful correlations were found, with the marble test pattern of 3xTg-AD mice being directly related to neophobia in the corner tests. In both genotypes, the increase of burying was reversed by chronic treatment with risperidone (1mg/kg, s.c.). In 3xTg-AD mice, the repetitive handling of animals during the treatment also exerted modulatory effects. These distinct patterns further characterize the modelling of BPSD-like symptoms in the 3xTg-AD mice, and provide another behavioural tool to assess the benefits of preventive and/or therapeutic strategies, as well as the potential action of risk factors for AD, in this animal model.

Persistent hyperactivity and distinctive strategy features in the Morris water maze in 3xTg-AD mice at advanced stages of disease.

Search strategies in the Morris water maze provide useful insights on cognitive function that may reveal genotype differences not reflected by escape latency or distance. Its analysis is pointed out as a complementary tool to better define the phenotype and the effect of treatments in animal models in which both cognitive impairment and behavioral symptoms reproduce the clinical complexity of the Alzheimer's disease patient. Here, we studied the performance of 13-month-old male 3xTg-AD mice in 3 different paradigms (cue learning, place task, and probe trial) and as compared with age-matched nontransgenic mice. The quantitative analysis (escape latency, distance, and speed) showed that in all tasks, the cognitive performance of 3xTg-AD mice was interfered with by a persistent hyperactive pattern. Their worse cognitive function was revealed by the qualitative features of nonsearch behaviors (floating and circling) and search strategies (single and /mixed, goal directed and nongoal directed). The search pattern was based on mixed and nongoal-directed strategies, in contrast to the single and goal-directed strategies used by controls. In the place task, poor cognitive flexibility of 3xTg-AD mice was also shown in persistence of search in the cue-trained position and the need to correct the strategy to find the new location. Trials involving a naïve situation (first trial of the cue task) or the difficulty of a new task (first trial of the place task and the probe trial) were the most suitable to show the deficits. This qualitative analysis may also be useful in the assessment of preventive or therapeutical treatments.

Abstract 197: Determining the Potential Role of cTnT Isoform Switching In the Development of Early Childhood Tropomyosin-Linked DCM

An oft-noted component of sarcomeric HCM and DCM is the observation that patients within families, carrying the same primary mutation, often exhibit significant phenotypic variability. This lack of a distinct link between genotype and phenotype has greatly complicated clinical management. In a recent study of two large unrelated multigenerational families carrying the tropomyosin (Tm) mutation Asp230Asn (D230N), a striking “bimodal” distribution of severity was observed. In these families, many children (<1 year) with the mutation presented with a severe form of DCM that led to sudden, often fatal congestive heart failure, while adults developed a mild to moderate DCM in mid-life. Of note, children who survived the initial presentation often recovered significant systolic function in adolescence and young adulthood. Therefore, to better understand the mechanism of this “bimodal” phenotype, we began to investigate the potential modulating role of isoform switching by other sarcomeric components. We hypothesize that the age-dependent remodeling seen in children with D230N Tm is a result of temporal isoform switches involving a closely linked Tm binding partner cardiac Troponin T (cTnT). Initial biophysical studies (circular dichroism and regulated in vitro motility, R-IVM) show that while D230N does not alter Tm’s thermal stability it does have a profound impact on myofilament activation. Both maximal velocity of filament sliding and calcium sensitivity were decreased. Furthermore, an additive decrease was observed in these parameters for R-IVM solutions containing cTnT 1 (fetal)+D230N Tm filaments as compared to cTnT 3 (adult)+D230N. Preliminary in vivo studies utilizing our novel double transgenic Tm-D230N x cTnT 1 mice show profound changes in wall thickness and chamber dilation, as compared to age-matched non-transgenic mice and D230N Tm mice. Further studies aim to model the “bimodal” clinical phenotype seen in families with D230N Tm and assess the potential for disease reversibility using a cardiac specific inducible cTnT 1 transgenic mouse model. Our goal is to use a translational approach to better understand the mechanism by which primary mutations lead to distinct clinical phenotypes in order to improve clinical management.

α7 Nicotinic Receptor Agonist Enhances Cognition in Aged 3xTg-AD Mice with Robust Plaques and Tangles

Alzheimer disease (AD) is a progressive neurodegenerative disorder with associated memory loss, spatial disorientation, and other psychiatric problems. Cholinergic system dysfunction is an early and salient feature of AD, and enhancing cholinergic signaling with acetylcholinesterase inhibitors is currently the primary strategy for improving cognition. The beneficial effects of acetylcholinesterase inhibitors, however, are typically short-lived and accompanied by adverse effects. Recent evidence suggests that activating α7 nicotinic acetylcholine receptors (α7 nAChR) may facilitate the specific modulation of brain cholinergic signaling, leading to cognitive enhancement and possibly to amelioration of AD pathologic findings. In the present study, we determined the effect of long-term treatment with the selective α7 nAChR agonist A-582941 in aged 3xTg-AD mice with robust AD-like pathology, which is particularly significant not only because this is the only mouse model that co-develops amyloid plaques and neurofibrillary tangles but also because it enabled us to explore whether A-582941 is able to restore brain function after the severe damage associated with AD. Analysis of β-amyloid deposits, tau phosphorylation, and inflammatory cells revealed that, overall, pathologic findings were unchanged. Rather, α7 nAChR activation induced expression of c-Fos and brain-derived neurotrophic factor and phosphorylation of cyclic adenosine monophosphate response element binding and neurotrophic tyrosine receptor kinase type 2. More important, A-582941 completely restored cognition in aged 3xTg-AD mice to the level of that in age-matched nontransgenic mice. These novel findings indicate that activating α7 nAChR is a promising treatment for cognitive impairment in AD.

Serum β-Amyloid Peptide Levels Spike in the Early Stage of Alzheimer- Like Plaque Pathology in an APP/PS1 Double Transgenic Mouse Model

Serum levels of β-amyloid (Aβ) peptides may represent an early biomarker in the diagnosis of Alzheimer's disease (AD). In the present study, we investigated the temporal kinetic changes in the levels of serum Aβ 1-42 and 40 in an amyloid precursor protein (APP)/presenilin (PS)1 double transgenic mouse model of AD. Serum Aβ peptide levels in 2-, 3-, 6-, 9- and 18-month old, and liver Aβ 1-40 level in 6-month old mice were measured using enzyme-linked immunosorbent assay (ELISA) kits. Results revealed that serum Aβ levels peaked in 3-month old transgenic mice, and the Aβ level in non-transgenic and transgenic mice is comparable in liver. Compared to the 6-month old transgenic mice, Congo red staining showed that the 3-month old transgenic mice had minimum brain Aβ plaques, corresponding to the early stage of Alzheimer-like plaque pathology, and confocal microscope images showed that the deposition of Aβ in their cerebral vessels was minimal. Furthermore, results of the water maze test, showed that memory was normal for the 3- month old transgenic mice when compared to age-matched non-transgenic mice. These results suggest that serum Aβ peptide levels may be peaked during the early stage of AD. Monitoring serum Aβ peptide levels in the potential AD population may provide an early diagnosis of AD prior to the appearance of clinical symptoms.