Brain Weight Research Articles

Alcohol Exposure Induces Nucleolar Stress and Apoptosis in Mouse Neural Stem Cells and Late-Term Fetal Brain.

Prenatal alcohol exposure (PAE) is a leading cause of neurodevelopmental disability through its induction of neuronal growth dysfunction through incompletely understood mechanisms. Ribosome biogenesis regulates cell cycle progression through p53 and the nucleolar cell stress response. Whether those processes are targeted by alcohol is unknown. Pregnant C57BL/6J mice received 3 g alcohol/kg daily at E8.5-E17.5. Transcriptome sequencing was performed on the E17.5 fetal cortex. Additionally, primary neural stem cells (NSCs) were isolated from the E14.5 cerebral cortex and exposed to alcohol to evaluate nucleolar stress and p53/MDM2 signaling. Alcohol suppressed KEGG pathways involving ribosome biogenesis (rRNA synthesis/processing and ribosomal proteins) and genes that are mechanistic in ribosomopathies (Polr1d, Rpl11; Rpl35; Nhp2); this was accompanied by nucleolar dissolution and p53 stabilization. In primary NSCs, alcohol reduced rRNA synthesis, caused nucleolar loss, suppressed proliferation, stabilized nuclear p53, and caused apoptosis that was prevented by dominant-negative p53 and MDM2 overexpression. Alcohol's actions were dose-dependent and rapid, and rRNA synthesis was suppressed between 30 and 60 min following alcohol exposure. The alcohol-mediated deficits in ribosomal protein expression were correlated with fetal brain weight reductions. This is the first report describing that pharmacologically relevant alcohol levels suppress ribosome biogenesis, induce nucleolar stress in neuronal populations, and involve the ribosomal/MDM2/p53 pathway to cause growth arrest and apoptosis. This represents a novel mechanism of alcohol-mediated neuronal damage.

Gross morpho-biometry, histometry and immunohistochemical investigations of pituitary gland in the juvenile and adult male African giant rats (Cricetomys gambianus)

This work was designed to investigate the morphometry and immunohistochemical features of pituitary glands in the African Giant Rats (AGR). Adult and juvenile AGR were sacrificed and their brains harvested, and the pituitary glands were carefully dissected. The weight, length and width of brains and pituitary glands were subsequently measured. Sections were prepared and stained using Haematoxylin and Eosin (H&E), Cresyl-violet and periodic-acid-Schiff (PAS) for histological analysis. Immunohistochemical analysis was carried out with Glial-Fibrillary-Acidic-Protein (GFAP) and Ionized-Calcium-Binding-Adapter-Molecule 1 (Iba1). Grossly, the AGR pituitary gland is a somehow laterally extended, saddle-shaped organ that is dorso-ventrally flattened. The gray-coloured adenohypophysis (anterior-pituitary lobe) was bigger in size than the whitish neurohypophysis (posterior-pituitary lobe) on physical examination. Histometrically, the adenohypophyseal length was noticeably greater than that of neurohypophysis in both juvenile and adult. Similarly, the adenohypophyseal and neurohypophyseal width in adult were found to be more than that of juvenile. Also, the histological staining of the neurohypophysis and adenohypophysis were distinct. In the neurohypophysis, fibrous and protoplasmic pituicytes were observed among fibres and Herring-bodies. Chromophils and chromophobes were identified in the adenohypophysis and melanotrophs in the intermediate lobe. Immunohistochemistry showed pituicytes in the neurohypophysis, which was positive with GFAP-antibody. With Iba1-antibody, the neurohypophysis expressed a stronger positive immunolabelling to microglia as compared to macrophages in the adenohypophysis. In conclusion, the gross and microscopic characteristics of pituitary glands of the AGR are found to be similar to other rodents and mammals. We recommend further study to compare morphometrical parameters between male and females of this model.

Reduced Levels of Brain-Derived Neurotrophic Factor Affect Body Weight, Brain Weight and Behavior.

Neurotrophins, which belong to the family of growth factors, not only play crucial roles during development but are also involved in many processes in the postnatal brain. One representative of neurotrophins is brain-derived neurotrophic factor (BDNF). BDNF plays a role in the regulation of body weight and neuronal plasticity and is, therefore, also involved in processes associated with learning and memory formation. Many of the studies on BDNF have been carried out using BDNF-deficient mice. Unfortunately, homozygous deletion of BDNF is lethal in the early postnatal stage, so heterozygous BDNF-deficient mice are often studied. Another possibility is the use of conditional BDNF-deficient mice in which the expression of BDNF is strongly downregulated in some brain cells, for example, in the neurons of the central nervous system, but the expression of BDNF in other cells in the brain is unchanged. To further reduce BDNF expression, we crossed heterozygous BDNF-deficient mice with mice carrying a deletion of BDNF in neurofilament L-positive neurons. These offspring are viable, and the animals with a strong reduction in BDNF in the brain show a strongly increased body weight, which is accompanied by a reduction in brain weight. In addition, these animals show behavioral abnormalities, particularly with regard to locomotion.

ALKBH8 contributes to neurological function through oxidative stress regulation.

Transfer RNA (tRNA) modification is essential for proper protein translation, as these modifications play important roles in several biological functions and disease pathophysiologies. AlkB homolog 8 (ALKBH8) is one of the nine mammalian ALKBH family molecules known to regulate selenoprotein translation through the modification of the wobble uridine (U34) in tRNA; however, its specific biological roles remain unclear. In this study, we investigated the role of ALKBH8 using Alkbh8-knockout (Albkh8-/-) mice, which were observed to have reduced 5-methoxycarbonylmethyluridine (mcm5U) and (S)-5-methoxycarbonylhydroxymethyluridine levels; notably, the mcm5U level was partially compensated only in the brain. The results of the novel object recognition test showed reduction in time to explore a novel object in Albkh8-/- mice; increased latency to fall in the rotarod performance test and latency to the immobility period in the forced swim test were also observed. These abnormal behaviors indicate dysfunction of the central nervous system. Furthermore, we observed reduced brain weight and ischemic pathological changes in the cerebral cortex and hippocampus in the form of weak eosin staining in the fiber tracts adjacent to the hippocampal cornu ammonis 1 region and an increase in pyramidal cells in the temporal lobe. Concordantly, we identified the differential expression of oxidative stress-related proteins and metabolites in the cerebral cortex and hippocampus using omics analyses. Finally, neurons and glial cells derived from Albkh8-/- mice show reduced mitochondrial membrane potential. Collectively, these findings indicate that ALKBH8 maintains neural function through an oxidative stress-regulatory mechanism.

C1ql3 knockout affects microglia activation, neuronal integrity, and spontaneous behavior in Wistar rats.

C1QL3 is widely expressed in the brain and is specifically produced by a subset of excitatory neurons. However, its function is still not clear. We established C1ql3-deficient rats to investigate the role of C1QL3 in the brain. C1ql3 knockout (KO) rats were generated using CRISPR/Cas9. C1ql3 KO was determined by polymerase chain reaction (PCR), DNA sequencing, and western blotting. Microglia morphology and cytokine expression with or without lipopolysaccharide (LPS) stimulus were analyzed using immunohistochemistry and real-time PCR. The brain structure changes in KO rats were examined using magnetic resonance imaging. Neuronal architecture alteration was analyzed by performing Golgi staining. Behavior was evaluated using the open field test, Morris water maze test, and Y maze test. C1ql3 KO significantly increased the number of ramified microglia and decreased the number of hypertrophic microglia, whereas C1ql3 KO did not influence the expression of pro-inflammatory factors and anti-inflammatory factors except IL-10. C1ql3 KO brains had more amoeboid microglia types and higher Arg-1 expression compared with the WT rats after LPS stimulation. The brain weights and HPC sizes of C1ql3 KO rats did not differ from WT rats. C1ql3 KO damaged neuronal integrity including neuron dendritic arbors and spine density. C1ql3 KO rats demonstrated an increase in spontaneous activity and an impairment in short working memory. C1ql3 KO not only interrupts the neuronal integrity but also affects the microglial activation, resulting in hyperactive behavior and impaired short memory in rats, which highlights the role of C1QL3 in the regulation of structure and function of both neuronal and microglial cells.

Prolonged stress response induced by chronic stress and corticosterone exposure causes adult neurogenesis inhibition and astrocyte loss in mouse hippocampus

Chronic stress is a pervasive and complex issue that contributes significantly to various mental and physical health disorders. Using the previously established chronic unpredictable stress (CUS) model, which simulates human stress situations, it has been shown that chronic stress induces major depressive disorder (MDD) and memory deficiency. However, this established model is associated with several drawbacks, such as limited research reproducibility and the inability to sustain stress response. To resolve these issues, we developed a new CUS model (CUS+C) that included exogenous corticosterone exposure to induce continuous stress response. Thereafter, we evaluated the effect of this new model on brain health. Thus, we observed that the use of the CUS+C model decreased body and brain weight gain and induced an uncontrolled coat state as well as depressive-like behavior in adult mice. It also impaired learning memory function and cognitive abilities, reduced adult hippocampal neurogenesis as well as the number of hippocampal astrocytes, and downregulated glial fibrillary acidic protein expression in the brains of adult mice. These findings can promote the utilization and validity of the animal stress model and provide new information for the treatment of chronic stress-induced depressive and memory disorders.

(068) Perfluorooctane Sulfonate (pfos) And Perfluorooctanic Acid (pfoa) Sub-chronic Exposure has Minimal Impact on Erectile Function in Sprague-dawley Ratsa

Abstract Introduction Per and polyfluoroalkyl substances (PFAS) are commonly used in industrial and consumer products and are environmental and health contaminants. The most common PFAS chemicals, perfluorooctane sulfonate (PFOS) and perfluorooctanic acid (PFOA), are used in firefighting foam, nonstick bakeware, water-resistant fabrics, grease-resistant paper and fire-resistant materials. PFAS is a known endocrine disruptor and can reduce testosterone and lower semen quality. The impact of PFAS exposure on erectile physiology is unknown. Objective Our study will assess the effect of PFOS and PFOA on erectile function in Sprague-Dawley rats. We hypothesize that PFOS and PFOA will decrease erectile function. Methods Adult male Sprague-Dawley rats were divided into three groups (n=10/group): 1) Control; 2) PFOS (10mg/kg/day); and 3) PFOA (10mg/kg/day). PFOS/PFOA was dissolved in 0.05% Tween 20 and administered in drinking water for 28 days. Controls received 0.05% Tween 20 in drinking water. The study was carried out in two different cohorts of rats (n=4 and n=6/group). Following 28 days of PFOS/PFOA exposure, rats were placed on regular drinking water for 2 weeks. Body weights were collected weekly and terminal organ weights of liver, testes, spleen, heart, lungs, brain, seminal vesicles, kidneys, bladder, and thymus were recorded. Erectile function was assessed prior to PFAS exposure and every 2 weeks thereafter via apomorphine-induced behavioral erections and yawns. Nerve-stimulated intracavernosal pressure and mean arterial pressure (ICP/MAP) was measured 2 weeks after exposure stopped. Results Four weeks of PFOS exposure significantly decreased body weight while PFOA exposure did not impact body weight (Con: 588±63.5g; PFOS: 453±16.3g; PFOA: 535±29.9g, p<0.01). The PFOS dose in the second cohort was overtly toxic with 5/6 rats dying following 3-4 weeks of exposure. Two weeks following PFOS/PFOA exposure, livers were markedly enlarged (Con: 19.4±2.85g; PFOS: 25.4±0.16g; PFOA: 20.2±3.77g, p<0.01), spleens were smaller (Con: 0.93±0.12g; PFOS: 0.65±0.03g; PFOA: 0.88±0.12g, p<0.05), and testes were larger in PFOS rats (Con: 1.8±0.07g; PFOS: 2.0±0.06g; PFOA: 1.8±0.07). No other organ weights were different across exposure groups. PFOS/PFOA exposed animals had similar numbers of apomorphine-induced erections throughout the 6 week period. Two weeks post-exposure, ICP/MAP was unchanged between all groups (n=5-10/group). Ongoing studies will assess testosterone levels. Conclusions A sub-chronic PFOS exposure markedly decreased body weight, increased liver size, decreased spleen weight, and increased testes weight. PFOA exposure did not impact body or organ weights. Following PFOS or PFOA exposure, there was no change in apomorphine-induced behavioral erections or ICP/MAP. Additionally, the dose of PFOS assessed was quite toxic to the second cohort of animals. Future studies will assess if a more chronic exposure will impact erectile function. Disclosure No.

Preliminary investigation of the activity of aqueous <i>Cucumis sativus</i> fruit extract on the prefrontal cortex in Wistar rats

Cucumis sativus Linn. is reported to have a wide variety of medicinal uses due to its abundance of carbohydrates, proteins, minerals and secondary metabolites. This study investigated the possible alterations in the prefrontal cortex of adult Wistar rats following the administration of aqueous Cucumis sativus fruit extract (ACSFE). Eighteen (18) Wistar rats, randomly divided into three groups (n=6), were used for this study. Group A served as control while Groups B and C received 250 mg/kg and 500 mg/kg of ACSFE respectively. At the end of the administration, the rats were weighed and the Y-maze test was utilized to evaluate spontaneous alternation of the experimental rats. Thereafter, the cerebri were harvested for antioxidant [Superoxide Dismutase (SOD), Catalase (CAT) and Glutathione (GSH)], lipid peroxidation [Malondialdehyde (MDA)] and histological evaluations. Results showed that there were no significant differences in the final body, absolute whole brain weights and spontaneous alternation of the extract-treated Groups when compared to the control. The histological sections of the prefrontal cortex of the rats in control Group were similar to the extract-treated groups showing normal pyramidal cells with open-face nuclei, basophilic cytoplasm and normal neuroglia cells. Taken together, ACSFE, at these doses, is not toxic to the prefrontal cortex of Wistar rats.

Neuroprotective effects of maternal melatonin administration in early-onset placental insufficiency and fetal growth restriction.

Early-onset fetal growth restriction (FGR) is associated with adverse outcomes. We hypothesised that maternal melatonin administration will improve fetal brain structure in FGR. Surgery was performed on twin-bearing ewes at 88 days (0.6 gestation), and FGR induced in one twin via single umbilical artery ligation. Melatonin was administered intravenously (6 mg/day) to a group of ewes commencing on day of surgery until 127 days (0.85 gestation), when the ewe/fetuses were euthanized, and fetal brains collected. Study groups were control (n = 5), FGR (n = 5), control+melatonin (control+MLT; n = 6) and FGR+melatonin (FGR + MLT; n = 6). Melatonin administration did not significantly alter fetal body or brain weights. Myelin (CNPase+) fibre density was reduced in FGR vs. control animals in most brain regions examined (p < 0.05) and melatonin treatment restored CNPase fibre density. Similar but less pronounced effect was seen with mature myelin (MBP+) staining. Significant differences in activated microglia (Iba-1) activity were seen between lamb groups (MLT mitigated FGR effect) in periventricular white matter, subventricular zone and external capsule (p < 0.05). Similar effects were seen in astrogliosis (GFAP) in intragyral white matter and cortex. Maternal melatonin administration in early onset FGR led to improved myelination of white matter brain regions, possibly mediated by decreased inflammation. Maternal melatonin administration might lead to neuroprotection in the growth-restricted fetus, possibly via dampening neuroinflammation and enhancing myelination. This preclinical study adds to the body of work on this topic, and informs clinical translation. Neuroprotection likely to improve long-term outcomes of this vulnerable infant group.

Influence of vasoactive intestinal polypeptide on growth performance, nutrient digestibility, nitrogen balance, and digestive enzyme activity in lambs.

This study evaluated if vasoactive intestinal polypeptide (VIP) influences growth performance, nutrient digestibility, nitrogen balance, and digestive enzyme activity. Sixteen wether lambs (69.6 ± 1.9kg) were housed in individual pens, adapted to a corn grain-based diet, and randomly assigned to 2 treatment groups. Lambs were injected intraperitoneally every other day for 28 d with saline (0.9% NaCl) containing no VIP (n = 8; control) or containing VIP (n = 8; 1.3 nmol/kg body weight [BW]). All lambs were transferred to individual metabolic crates for the final 7 d of the experiment to measure nitrogen balance and nutrient digestibility. At the end of the treatment period, lambs were slaughtered, and pancreatic tissue, small intestinal tissue, and rumen fluid were collected for protein, digestive enzymes, ruminal pH, and volatile fatty acid (VFA) analyses. Lambs treated with VIP had greater final BW, average daily gain, and gain:feed (P = 0.01, 0.05, 0.03, respectively). No differences between treatment groups were observed (P ≥ 0.25) for nutrient intake, digestibility, nitrogen retention, ruminal pH, and VFA concentrations. Moreover, VIP treatment did not influence (P ≥ 0.19) plasma glucose, urea N, and insulin concentrations. Treatment with VIP increased (P = 0.03) relative cecum weight (g/kg BW) and decreased (P = 0.05) relative brain weight. Pancreatic and intestinal digestive enzyme activities, except for duodenal maltase (P = 0.02), were not influenced (P ≥ 0.09) by VIP treatment. These data suggest that the administration of VIP may have potential to improve average daily gain and gain:feed in lambs fed grain-based diets.

Neurobehavioral deficits, histoarchitectural alterations, parvalbumin neuronal damage and glial activation in the brain of male Wistar rat exposed to Landfill leachate

Concerns about inappropriate disposal of waste into unsanitary municipal solid waste landfills around the world have been on the increase, and this poses a public health challenge due to leachate production. The neurotoxic effect of Gwagwalada landfill leachate (GLL) was investigated in male adult Wistar rats. Rats were exposed to a 10% concentration of GLL for 21 days. The control group received tap water for the same period of the experiment. Our results showed that neurobehavior, absolute body and brain weights and brain histomorphology as well as parvalbumin interneurons were severely altered, with consequent astrogliosis and microgliosis after 21 days of administrating GLL. Specifically, there was severe loss and shrinkage of Purkinje cells, with their nucleus, and severe diffused vacuolations of the white matter tract of GLL-exposed rat brains. There was severe cell loss in the granular layer of the cerebellum resulting in a reduced thickness of the layer. Also, there was severe loss of dendritic arborization of the Purkinje cells in GLL-exposed rat brains, and damage as well as reduced populations of parvalbumin-containing fast-spiking GABAergic interneurons in various regions of the brain. In conclusion, data from the present study demonstrated the detrimental effects of Gwagwalada landfill leachate on the brain which may be implicated in neuropsychological conditions.

Coordination of anti-CTLA-4 with whole-brain radiation therapy decreases tumor burden during treatment in a novel syngeneic model of lung cancer brain metastasis

Lung cancer is the most common primary tumor to metastasize to the brain. Although advances in lung cancer therapy have increased rates of survival over the past few decades, control and treatment of lung cancer brain metastasis remains an urgent clinical need. Herein, we examine the temporal coordination of α-CTLA-4 administration in combination with whole-brain radiation therapy in a syngeneic preclinical model of lung cancer brain metastasis in both C57Bl/6 and athymic nude mice. Brain tumor burden, survival, and weight loss were monitored. Immunotherapy administration 24 h prior to irradiation resulted in increased brain tumor burden, while administration of immunotherapy 12 h after radiation decreased tumor burden. Neither of the treatments affected survival outcomes or weight loss due to brain tumor recurrence. These findings suggest that the coordination of α-CTLA-4 administration in addition to whole-brain radiation therapy may be a viable strategy for reduction of tumor burden for the management of lung cancer brain metastasis.

JADE1 is dispensable for the brain development in mice

In mammalian brain development, WNT signaling balances proliferation and differentiation of neural progenitor cells, and is essential for the maintenance of regular brain development. JADE1 is a candidate transcription co-factor essential for DNA replication, cell division, and cell cycle regulation. In 293T cells, JADE1 is stabilized by von Hippel–Lindau protein pVHL, promotes the β-catenin ubiquitination and thus blunts canonical WNT signaling. Furthermore, JADE1 inhibits β-catenin-induced ectopic axis formation in Xenopus embryos. However, JADE1's role in mammalian brain development remains unknown. Here, we generated a new Jade1 knockout mouse line using CRISPR-Cas9 technology. We found that JADE1 null resulted in decreased survival rate, reduced body weight and brain weight in mice. However, histological analysis revealed a normal brain development. Furthermore, Jade1 null neural progenitor cells proliferated normally in vivo and in vitro. RNA-seq analysis further showed that JADE1 loss did not affect the cerebral cortex gene expression. Our findings indicate that JADE1 is dispensable for developing the cerebral cortex in mice.

In ovo injection of testosterone to yolk sac modulates early posthatching development and physiology of male chick in broilers

The aim of this study was to investigate the effects of in ovo testosterone injection into the yolk sac of embryos on physiology and development of broiler chicks during the early posthatching period. A total of 1,010 hatching eggs were obtained from the Ross genotype. Trial design was conducted with a noninjected group (control) and injection groups in which 100 µL sesame oil, or 100 µL sesame oil + 0.50 µmol testosterone were injected into the yolk sac of the embryo on d 6 or d 12 of incubation. Testosterone hormone level was measured in the egg yolk and albumen at onset of incubation, in the yolk sac on d 19 of incubation and in the residual yolk sac at hatching. Weights of chick, yolk sac and organ, morphological traits (body length, lengths of bilateral traits and beak length), asymmetrical development of bilateral morphological traits and body mass index were measured at hatching and on d 7 after hatching. Testosterone, corticosterone and growth hormone levels were determined in blood plasma obtained from male chicks at hatching and on d 7 of chick age. Chick weight was not affected, plasma testosterone level and brain weight decreased, while body mass index, plasma corticosterone and growth hormone levels increased by administering 0.50 µmol testosterone on d 12 of embryonic age. However, plasma testosterone and growth hormone levels did not change, chick weight increased, while plasma corticosterone level and the chick body length decreased by administering 0.50 µmol testosterone on d 6 of embryonic age. A significant interaction between chick age and in ovo testosterone administration resulted in an increase in lung weight of chicks. In conclusion, this study found that in ovo testosterone administered at different embryonic ages due to age-specific effects of testosterone in the yolk sac of embryo modulates development related to physiological parameters of male broiler chicks during early posthatching period.

Differential effects of neuronal Cdkn2a over‐expression in mouse brain

AbstractBackgroundAging is the primary risk factor for Alzheimer’s disease (AD). With aging, senescent cells accumulate in the body and the brain. Cells that become senescent cease contributing to homeostasis but do not typically undergo apoptosis. Prior studies have identified a broad association between increased cellular senescence and AD‐like pathology and have identified senescent cells in AD patient brain and mouse models of AD‐like pathology. However, contributions of senescent cells to disease progression remains uncertain.MethodThe two gene products of the senescence regulator Cdkn2a (p16‐Ink4a and p19‐Arf) were overexpressed using intracranial delivery of adeno‐associated viral vectors (AAV). Mice were injected with 2 µL of 1×1013, 5×1012, or 1×1012 vg/mL of AAV‐Arf and tissue was collected two months post‐injection. Control mice were injected with AAV empty capsid. Brain weights, NeuN IHC, and p19‐Arf mRNA were assessed. A second cohort of mice was injected with AAV‐Ink, AAV‐Arf, AAV‐Ink &amp; AAV‐Arf (co‐injection), or AAV‐GFP and followed for four months post‐injection. We assessed body mass, brain mass, NeuN IHC, and expression of senescence‐induced genes by PCR‐array and qRT‐PCR. A third experiment over‐expressing p19‐Arf in PS19 mice is ongoing.ResultWe observed that animals over‐expressing p19‐Arf failed to gain body mass up to four months post‐injection. Post‐mortem, we found that over‐expression of p19‐Arf is toxic to neurons, reducing gross brain mass and NeuN area staining. Furthermore, a greater number of differentially regulated genes were observed in mice over‐expressing p19‐Arf than in mice over‐expressing p16‐Ink4a. We confirmed increased expression of the senescence‐regulator p21 in mice over‐expressing p19‐Arf, but not p16‐Ink4a, by qPCR. In a separate experiment, we replicated the finding of neurotoxicity induced by over‐expression of p19‐Arf at only two months post‐injection and determined the optimal viral titer to administer that induces significant over‐expression with minimal neurotoxicity for use in future studies.ConclusionAs observed in cultured cells, over‐expression of Cdkn2a seems to increase markers of senescence. Effects on tau pathology will be examined in the PS19 mouse model of tauopathy. Cell type‐specific expression in neurons, astroglia, and microglia will be used to elucidate cell type specific contributions to senescence‐induced disease progression.

GFAP Upregulation by Astrocytes May Attenuate Phospho‐Tau Levels in a Tauopathy Mouse Model

AbstractBackgroundAstrocytes react to amyloid‐β plaques and phospho‐tau (pTau) neurofibrillary tangles in the Alzheimer’s disease brain but their net effect on these Alzheimer’s neuropathological hallmarks remains controversial. A well‐known feature of these so‐called “reactive astrocytes” is the upregulation of the intermediate filament glial fibrillary acidic protein (GFAP), which is thought to be necessary for astrocyte process motility and glial scar formation. Here we asked whether this cytoskeletal remodeling helps reactive astrocytes control the burden of pTau species and/or protect synapses and neurons.MethodWe overexpressed human GFAP isoform 1 specifically in astrocytes of 4‐month‐old, sex‐balanced, THY‐Tau22 mice (Thy1.2‐MAPT G272V/P301S 1N4R, GFAP mice, n = 11)—when neurofibrillary tangles start to appear in the hippocampal CA1 subfield—using a viral transfer strategy with single retro‐orbital intravenous injection of AAV‐PHP.B (2.5×1011 vg) and the gfaABC1D promoter. We euthanized the mice at 11 months of age (i.e., prior to the tauopathy plateau) and performed immunohistochemical and/or biochemical analysis of astrocyte, tau, and synaptic markers. Negative control groups consisted of THY‐Tau22 littermates injected with either phosphate‐buffered saline (PBS mice, n = 9) or an AAV‐PHP.B vector encoding the enhanced green fluorescent protein (EGFP mice, n = 10).ResultsImmunohistochemistry confirmed the astrocyte‐specific expression of human GFAP with an apparent integration in their intermediate filament network. We observed statistically significant reductions or marginally significant trends toward decrease in hippocampal SDS‐soluble levels AT8/pTauSer202/Thr205 and AT8‐immunoreactive area fraction, and a shift of AT180/pTauThr231 from SDS‐soluble (decreased) to TBS‐soluble (increased) hippocampal protein fractions, in GFAP vs. EGFP and/or PBS mice, but no changes in soluble or insoluble total tau or AT270/pTauThr181 across groups. In the cortex, we detected no changes in soluble or insoluble total tau, AT8/pTauSer202/Thr205, or AT270/pTauThr181 levels, nor in AT8‐immunoreactive area. Lastly, we found no significant differences across groups in brain weight, cortical or hippocampal areas, nor in the cortical levels of synaptophysin, Psd95, or the glutamate transporters Eaat1/Glast‐1 and Eaat2/Glt‐1.ConclusionOur findings indicate that GFAP upregulation by astrocytes—a classic feature of reactive astrogliosis—may attenuate neuronal pTau burden in a tauopathy mouse model. Ongoing work will further elucidate whether this aspect of reactive astrocytes impacts pTau‐induced neurodegeneration.

Protective effects of gestational folic acid and egg yolk powder solution intubation on motor coordination, anxiety, cognition, acetylcholinesterase activity and DNA fragmentation in prenatal alcohol exposed rats

AbstractBackgroundDevelopment of neurobehavioural disorders can occur in the postnatal life of foetuses prenatally exposed to alcohol, regardless of the alcohol type consumed during pregnancy. Hence, the need to investigate the efficacy of proposed pharmaco‐nutritional therapy in mediating potential behavioural and cholinergic impairments in prenatal alcohol exposed (PAE) fetuses.MethodWe investigated whether PAE exacerbates anxiety, motor coordination, cognitive function, cerebral cortex acetylcholinesterase (ACh) activity, DNA fragmentation and assessed associations among parental and PAE rats’ cerebral cortex ACh activity. Thirty female Wistar rats were mated in the following groups (n = 6): 1: Negative control (distilled water only), 2: Positive control (40% EtOH), 3: local gin (LG), 4: local gin+egg yolk solution(LGEY) 5: local gin +egg yolk solution+folic acid(LGEYFA). Statistical significance of obtained data was measured at p&lt;0.05 using regression model, ANOVA and Tukey’s PostHoc tests (GraphPad 5).ResultWhen compared to the negative control, all alcohol groups (supplemented or not) had significantly lower latency of fall, working memory, percentage alternation etc. Although the brain weight of PAE rats in group 2 (positive control) did not change significantly (p = 0.159), critically reduced brain weights seen in group 3 (LG, p&lt;0.001) were normalized in the supplemented groups (4‐LGEY and 5‐LGE). Cortex protein levels was unchanged in all maternal rats regardless of alcohol intubation. However, ACh cerebral cortex activity was significantly reduced in PAE rats from non‐supplemented groups (2 and 3). Necrosis and fragmentation were also seen in agarose gel electrophoregram (AGE) of gDNA isolated from PAE rats’ brain.ConclusionPrenatal alcohol exposure predisposes to severe neurobehavioural and cognitive deficits while gestational folic acid+egg yolk solution may be a therapeutic target for high risk PAE pregnancies.

Relating neighborhood deprivation to childhood obesity in the ABCD study: Evidence for theories of neuroinflammation and neuronal stress.

We evaluated whether relationships between area deprivation (ADI), body mass index (BMI) and brain structure (e.g., cortical thickness, subcortical volume) during preadolescence supported the immunologic model of self-regulation failure (NI) and/or neuronal stress (NS) theories of overeating. The NI theory proposes that ADI causes structural alteration in the brain due to the neuroinflammatory effects of overeating unhealthy foods. The NS theory proposes that ADI-related stress negatively impacts brain structure, which causes stress-related overeating and subsequent obesity. Data were gathered from the Adolescent Brain Cognitive Development Study (9 to 12 years old; n = 3,087, 51% male). Linear mixed-effects models identified brain regions that were associated with both ADI and BMI; longitudinal associations were evaluated with mediation models. The NI model included ADI and BMI at 9 to 10 years old and brain data at 11 to 12 years old. The NS model included ADI and brain data at 9 to 10 years old and BMI at 11 to 12 years old. BMI at 9 to 10 years old partially mediated the relationship between ADI and ventral diencephalon (DC) volume at 11 to 12 years old. Additionally, the ventral DC at 9 to 10 years old partially mediated the relationship between ADI and BMI at 11 to 12 years old, even in youth who at baseline, were of a healthy weight. Results were unchanged when controlling for differences in brain structure and weight across the 2-years. Greater area deprivation may indicate fewer access to resources that support healthy development, like nutritious food and nonstressful environments. Our findings provide evidence in support of the NI and NS theories of overeating, specifically, with greater ADI influencing health outcomes of obesity via brain structure alterations. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Utilization of the novel adeno‐associated virus PHP.eB serotype to modulate Intersectin 1 expression in the Ts65Dn mouse model of Down syndrome

AbstractBackgroundDown Syndrome (DS) and Alzheimer’s disease (AD) include cholinergic neurodegeneration which parallels cognitive decline. Triplicated genes in DS are thought to play a role in basal forebrain cholinergic neuron (BFCN) pathology; one avenue to assess triplicated genes’ role is to normalize their expression in DS mouse models by stereotaxic injection of adeno‐associated viruses (AAVs) carrying silencing constructs such as single hairpin mRNA (shRNA). However, stereotaxic surgeries have drawbacks particularly when targeting areas lying deep within the brain. The introduction of the AAV‐PHP.eB serotype, which can cross the blood‐brain‐barrier when introduced into peripheral vasculature, has been shown to vary in efficiency depending on mouse background. Here, we investigated tropism of the AAV‐PHP.eB serotype in the Ts65Dn mouse, the most commonly used DS mouse model. We then used AAV‐PHP.eB to assess our ability to globally modulate expression of intersectin 1 (ITSN1), a protein triplicated in DS that may relate to BFCN dysfunction and memory impairments.MethodsWe retro‐orbitally injected N = 16 4‐4.5 month‐old male mice, (C57Bl, Ts65Dn trisomic and normosomic) with AAV‐PHP.eB‐CamKII‐GFP‐scrmble‐shRNA, to assess tropism and optimize virus concentration (2, 5, and 10µL). Four weeks post injection we imaged for GFP expression in 50µm coronal sections. To knock down ITSN1 globally, we injected N = 58 Ts65Dn mice (3 months, balanced by sex, genotype, virus) with either 5μl AAV‐PHP.eB‐U6‐scrmble‐GFP (control) or AAV‐PHP.eB‐U6‐shITSN1‐GFP (ITSN1); mice were behaviorally tested at 7 months and euthanized at 8 months followed by tissue collection.ResultsMice injected with AAV‐PHP.eB‐CamKII‐GFP‐scrmble‐shRNA showed GFP expression 4 weeks following injection, with robust expression visible with 5µL virus. Mice subsequently injected with control and ITSN1 AAVs showed significant effects of ITSN1 knockdown, including increased tremors, increased latency in the radial arm water maze – suggesting impaired spatial reference learning and memory – decreased brain weight, and altered weight change.ConclusionThe AAV‐PHP.eB serotype shows successful CNS tropism in the Ts65Dn mouse model, with 5µL of AAV providing the best efficiency throughout key brain regions affected in DS and AD. Furthermore, the AAV‐PHP.eB serotype can be used to modulate expression of genes triplicated in DS to investigate their mechanistic role in neurodegeneration both molecularly and behaviorally.

Knockdown of Placental Major Facilitator Superfamily Domain Containing 2a in Pregnant Mice Reduces Fetal Brain Growth and Phospholipid Docosahexaenoic Acid Content.

Docosahexaenoic acid (DHA) is an n-3 long chain polyunsaturated fatty acid critical for fetal brain development that is transported to the fetus from the mother by the placenta. The lysophosphatidylcholine (LPC) transporter, Major Facilitator Superfamily Domain Containing 2a (MFSD2a), is localized in the basal plasma membrane of the syncytiotrophoblast of the human placenta, and MFSD2a expression correlates with umbilical cord blood LPC-DHA levels in human pregnancy. We hypothesized that placenta-specific knockdown of MFSD2a in pregnant mice reduces phospholipid DHA accumulation in the fetal brain. Mouse blastocysts (E3.5) were transduced with an EGFP-expressing lentivirus containing either an shRNA targeting MFSD2a or a non-coding sequence (SCR), then transferred to pseudopregnant females. At E18.5, fetuses were weighed and their placenta, brain, liver and plasma were collected. MFSD2a mRNA expression was determined by qPCR in the brain, liver and placenta and phospholipid DHA was quantified by LC-MS/MS. MFSD2a-targeting shRNA reduced placental mRNA MFSD2a expression by 38% at E18.5 (n = 45, p < 0.008) compared with SCR controls. MFSD2a expression in the fetal brain and liver were unchanged. Fetal brain weight was reduced by 13% (p = 0.006). Body weight, placenta and liver weights were unaffected. Fetal brain phosphatidyl choline and phosphatidyl ethanolamine DHA content was lower in fetuses with placenta-specific MFSD2a knockdown. Placenta-specific reduction in expression of the LPC-DHA transporter MFSD2a resulted in reduced fetal brain weight and lower phospholipid DHA content in the fetal brain. These data provide mechanistic evidence that placental MFSD2a mediates maternal-fetal transfer of LPC-DHA, which is critical for brain growth.