Impact of diet-induced obesity on the mouse brain phosphoproteome

Genes Selectively Expressed in Rat Organs

Background

Understanding organic functions at a molecular level is important for scientists to unveil the disease mechanism and to develop diagnostic or therapeutic methods.

Aims

The present study tried to find genes selectively expressed in 11 rat organs, including the adrenal gland, brain, colon, duodenum, heart, ileum, kidney, liver, lung, spleen, and stomach.

Materials and Methods

Three normal male Sprague-Dawley (SD) rats were anesthetized, their organs mentioned above were harvested, and RNA in the fresh organs was extracted. Purified RNA was reversely transcribed and sequenced using the Solexa high-throughput sequencing technique. The abundance of a gene was measured by the expected value of fragments per kilobase of transcript sequence per million base pairs sequenced (FPKM). Genes in organs with the highest expression level were sought out and compared with their median value in organs. If a gene in the highest expressed organ was significantly different (p < 0.05) from that in the medianly expressed organ, accompanied by q value < 0.05, and accounted for more than 70% of the total abundance, the gene was assumed as the selective gene in the organ.

Results & Discussion

The Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Ontology (GO) pathways were enriched by the highest expressed genes. Based on the criterion, 1,406 selective genes were screened out, 1,283 of which were described in the gene bank and 123 of which were waiting to be described. KEGG and GO pathways in the organs were partly confirmed by the known understandings and a good portion of the pathways needed further investigation.

Conclusion

The novel selective genes and organic functional pathways are useful for scientists to unveil the mechanisms of the organs at the molecular level, and the selective genes' products are candidate disease markers for organs.

Association between cognitive impairment promoted by high-fat diet and increase in PTEN phosphorylation

The purpose of this study was to observe the changes in memory impairment and hippocampal phosphorylated protein levels in mice caused by obesity, and to explore the key phosphorylation modification proteins and pathways of memory impairment induced by high-fat diet. First, sixteen C57BL/6J mice were randomly divided into simple obese group (group H, n=8) and normal control group (group C, n=8). And at the end of the experiment, the cognitive function of the mice was assessed by Morris water maze and serological indexes were measured. Finally, phosphoproteomics was used to identify the differentially phosphorylted protein expression in the hippocampus of obese mice. Compared with group C, mice in group H had significantly decreased learning and memory abilities, and significantly increased body weight, blood glucose and lipid levels. The results of the phosphoproteomics analysis showed 442 up-regulated differentially phosphorylated proteins and 402 down-regulated differentially phosphorylated proteins. Further protein-protein interaction (PPI) analysis revealed pathway hub proteins, including β-actin (ACTB), Phosphatase and tensin homolog deleted on chromosome ten (PTEN), Phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1), mammalian target of rapamycin (mTOR), ribosomal protein 6 (RPS6), etc. Notably, the hub proteins PTEN, PIK3R1, and mTOR were jointly involved in the mTOR signaling pathway. Our study shows for the first time that a high-fat diet increases the phosphorylation of PTEN proteins, which may affect cognitive function.

Aphanizomenon flos-aquae (AFA) Extract Prevents Neurodegeneration in the HFD Mouse Model by Modulating Astrocytes and Microglia Activation

Obesity and related metabolic dysfunctions are associated with neurodegenerative diseases, such as Alzheimer's disease. Aphanizomenon flos-aquae (AFA) is a cyanobacterium considered a suitable supplement for its nutritional profile and beneficial properties. The potential neuroprotective effect of an AFA extract, commercialized as KlamExtra^®, including the two AFA extracts Klamin^® and AphaMax^®, in High-Fat Diet (HFD)-fed mice was explored. Three groups of mice were provided with a standard diet (Lean), HFD or HFD supplemented with AFA extract (HFD + AFA) for 28 weeks. Metabolic parameters, brain insulin resistance, expression of apoptosis biomarkers, modulation of astrocytes and microglia activation markers, and Aβ deposition were analyzed and compared in the brains of different groups. AFA extract treatment attenuated HFD-induced neurodegeneration by reducing insulin resistance and loss of neurons. AFA supplementation improved the expression of synaptic proteins and reduced the HFD-induced astrocytes and microglia activation, and Aβ plaques accumulation. Together, these outcomes indicate that regular intake of AFA extract could benefit the metabolic and neuronal dysfunction caused by HFD, decreasing neuroinflammation and promoting Aβ plaques clearance.

Long-Term Ingestion of Sicilian Black Bee Chestnut Honey and/or D-Limonene Counteracts Brain Damage Induced by High Fat-Diet in Obese Mice

Obesity is linked to neurodegeneration, which is mainly caused by inflammation and oxidative stress. We analyzed whether the long-term intake of honey and/or D-limonene, which are known for their antioxidant and anti-inflammatory actions, when ingested separately or in combination, can counteract the neurodegeneration occurring in high fat diet (HFD)-induced obesity. After 10 weeks of HFD, mice were divided into: HFD-, HFD + honey (HFD-H)-, HFD + D-limonene (HFD-L)-, HFD + honey + D-limonene (HFD-H + L)-fed groups, for another 10 weeks. Another group was fed a standard diet (STD). We analyzed the brain neurodegeneration, inflammation, oxidative stress, and gene expression of Alzheimer's disease (AD) markers. The HFD animals showed higher neuronal apoptosis, upregulation of pro-apoptotic genes Fas-L, Bim P27 and downregulation of anti-apoptotic factors BDNF and BCL2; increased gene expression of the pro-inflammatory IL-1β, IL-6 and TNF-α and elevated oxidative stress markers COX-2, iNOS, ROS and nitrite. The honey and D-limonene intake counteracted these alterations; however, they did so in a stronger manner when in combination. Genes involved in amyloid plaque processing (APP and TAU), synaptic function (Ache) and AD-related hyperphosphorylation were higher in HFD brains, and significantly downregulated in HFD-H, HFD-L and HFD-H + L. These results suggest that honey and limonene ingestion counteract obesity-related neurodegeneration and that joint consumption is more efficacious than a single administration.

Perfluorooctanoic acid-induced developmental cardiotoxicity in chicken embryo: Roles of miR-490-5p

Perfluorooctanoic acid (PFOA) could induce developmental toxicities, affecting various organs, including the heart. Although peroxisome-proliferation activated receptor alpha (PPARα) had been identified as a major target of PFOA, PPARα-independent effects are frequently reported. To further elucidate the mechanism of toxicity in PFOA-induced developmental cardiotoxicity, RNA-seq analysis was performed in hatchling chicken hearts developmentally exposed to vehicle or 2 mg/kg (egg weight) PFOA. RT-PCR and western blotting were then performed to confirm the identified potential targets. Furthermore, lentivirus was designed to overexpress and silence identified target miRNA in developing chicken embryo, and the resulting phenotypes were investigated. 21 miRNAs and 1142 mRNAs were identified to be affected by developmental exposure to PFOA in chicken embryo hearts. Among the identified differentially expressed miRNAs, miR-490-5p was confirmed to be significantly affected by PFOA exposure, along with its downstream targets, Synaptosome associated protein 91 (SNAP91) and LY6/PLAUR domain containing 6 (LYPD6), as indicated by RT-PCR and western blotting results. Lentivirus overexpressing miR-490-5p mimicked the phenotype induced by PFOA exposure, while lentivirus silencing miR-490-5p alleviated PFOA-induced changes. Similar patterns were also observed in the expression of downstream target genes, SNAP91 and LYPD6. In summary, miR-490-5p and its downstream genes, SNAP91 and LYPD6 are associated with PFOA-induced developmental cardiotoxicity in chicken embryo, which might help to further elucidate the mechanism of PFOA-induced developmental cardiotoxicity.

Heart fatty acid-binding protein is associated with phosphorylated tau and longitudinal cognitive changes

Background

Perturbation of lipid metabolism is associated with Alzheimer’s disease (AD). Heart fatty acid-binding protein (HFABP) is an adipokine playing an important role in lipid metabolism regulation.

Materials and methods

Two datasets separately enrolled 303 and 197 participants. First, we examine the associations of cerebrospinal fluid (CSF) HFABP levels with cognitive measures [including Mini-Mental State Examination (MMSE), Clinical Dementia Rating sum of boxes (CDRSB), and the cognitive section of Alzheimer’s Disease Assessment Scale] and AD biomarkers (CSF amyloid beta and tau levels). Second, we examine the longitudinal associations of baseline CSF HFABP levels and the variability of HFABP with cognitive measures and AD biomarkers. Structural equation models explored the mediation effects of AD pathologies on cognition.

Results

We found a significant relationship between CSF HFABP level and P-tau (dataset 1: β = 2.04, p &lt; 0.001; dataset 2: β = 1.51, p &lt; 0.001). We found significant associations of CSF HFABP with longitudinal cognitive measures (dataset 1: ADAS13, β = 0.09, p = 0.008; CDRSB, β = 0.10, p = 0.003; MMSE, β = −0.15, p &lt; 0.001; dataset 2: ADAS13, β = 0.07, p = 0.004; CDRSB, β = 0.07, p = 0.005; MMSE, β = −0.09, p &lt; 0.001) in longitudinal analysis. The variability of HFABP was associated with CSF P-tau (dataset 2: β = 3.62, p = 0.003). Structural equation modeling indicated that tau pathology mediated the relationship between HFABP and cognition.

Conclusion

Our findings demonstrated that HFABP was significantly associated with longitudinal cognitive changes, which might be partially mediated by tau pathology.

Superhydrophilic nanocomposite adsorbents modified via nitrogen-rich phosphonate-functionalized ionic liquid linkers: enhanced phosphopeptide enrichment and phosphoproteome analysis of tau phosphorylation in the hippocampal lysate of Alzheimer's transgenic mice

In this study, new graphene-based IMAC nanocomposites for phosphopeptide enrichment were prepared according to the guideline of our new design strategy. Superhydrophilic polyethyleneimine (PEI) was introduced, to which a phosphonate-functionalized ionic liquid (PFIL) was covalently bound, to form superhydrophilic and cationic surface layers with high densities of nitrogen atoms, phosphonate functional groups, and high-loading metal ions. Due to the combined features of superhydrophilicity, flexibility, highly dense metal binding sites, large surface area and excellent size-exclusion effect, the fabricated nanocomposite G@mSiO₂@PEI-PFIL-Ti⁴⁺ exhibits superior detection sensitivity to enrich phosphopeptides (tryptic β-casein digest, 0.1 fmol), and extraordinary enrichment specificity to enrich phosphopeptides from a digest mixture of β-casein and bovine serum albumin (BSA) (molar ratio, 1 : 12 000). The excellent size-exclusion effect was also observed, and 27 endogenous phosphopeptides were identified in human saliva. All these results could be attributed to the unique superhydrophilic nanocomposite structure with a high density of a cationic linker modified with phosphonate functionality. Moreover, G@mSiO₂@PEI-PFIL-Ti⁴⁺ adsorbents were used to extract phosphopeptides from the tryptic digests of hippocampal lysates for quantitative phosphoproteome analysis. The preliminary results indicate that 1649 phosphoproteins, 3286 phosphopeptides and 4075 phosphorylation sites were identified. A total of 13 Alzheimer's disease (AD)-related phosphopeptides within tau proteins were detected with a wide coverage from p-Thr111 to p-Ser404, in which the amounts of some phoshopeptides at certain sites in AD transgenic mice were found statistically higher than those in wild type littermates. Besides, phosphorylated neurofilament heavy chains, a potential biomarker for amyotrophic lateral sclerosis and traumatic brain injury, were also identified. Finally, the adsorbent was applied to human cerebrospinal fluid (CSF) and blood samples. 5 unique phosphopeptides of neuroendocrine specific VGF were identified in the CSF, while many phosphopeptides originated from the nervous system were found in the blood sample. All these results suggest that our new IMAC materials exhibit unbiased enrichment ability with superior detection sensitivity and specificity, allowing the global phosphoproteome analysis of complicated biological samples more convincible and indicating the potential use in disease diagnosis.

A High-Fat Diet Modifies Brain Neurotransmitter Profile and Hippocampal Proteome and Morphology in an IUGR Pig Model

Intrauterine Growth Restriction (IUGR) hinders the correct growth of the fetus during pregnancy due to the lack of oxygen or nutrients. The developing fetus gives priority to brain development ("brain sparing"), but the risk exists of neurological and cognitive deficits at short or long term. On the other hand, diets rich in fat exert pernicious effects on brain function. Using a pig model of spontaneous IUGR, we have studied the effect on the adult of a long-term high-fat diet (HFD) on the neurotransmitter profile in several brain areas, and the morphology and the proteome of the hippocampus. Our hypothesis was that animals affected by IUGR (born with low birth weight) would present a different susceptibility to an HFD when they become adults, compared with normal birth-weight animals. Our results indicate that HFD affected the serotoninergic pathway, but it did not provoke relevant changes in the morphology of the hippocampus. Finally, the proteomic analysis revealed that, in some instances, NBW and LBW individuals respond to HFD in different ways. In particular, NBW animals presented changes in oxidative phosphorylation and the extracellular matrix, whereas LBW animals presented differences in RNA splicing, anterograde and retrograde transport and the mTOR pathway.

Differential proteomic analysis of mouse cerebrums with high-fat diet (HFD)-induced hyperlipidemia

Hyperlipidemia is a chronic disease characterized by elevated blood cholesterol and triglycerides and there is accumulated evidence that the disease might affect brain functions. Here we report on a proteomic analysis of the brain proteins in hyperlipidemic mice. Hyperlipidemia was successfully induced in mice by a 20 week high-fat diet (HFD) feeding (model group). A control group with a normal diet and a treatment group with HFD-fed mice treated with a lipid-lowering drug simvastatin (SIM) were established accordingly. The proteins were extracted from the left and right cerebrum hemispheres of the mice in the three groups and subjected to shotgun proteomic analysis. A total of 4,422 proteins were detected in at least half of the samples, among which 324 proteins showed significant difference (fold change >1.5 or <0.67, p < 0.05) in at least one of the four types of comparisons (left cerebrum hemispheres of the model group versus the control group, right cerebrums of model versus control, left cerebrums of SIM versus model, right cerebrums of SIM versus model). Biological process analysis revealed many of these proteins were enriched in the processes correlated with lipid metabolism, neurological disorders, synaptic events and nervous system development. For the first time, it has been reported that some of the proteins have been altered in the brain under the conditions of HFD feeding, obesity or hyperlipidemia. Further, 22 brain processes-related proteins showed different expression in the two cerebrum hemispheres, suggesting changes of the brain proteins caused by hyperlipidemia might also be asymmetric. We hope this work will provide useful information to understand the effects of HFD and hyperlipidemia on brain proteins.

A zebrafish pparγ gene deletion reveals a protein kinase network associated with defective lipid metabolism

Peroxisome proliferator-activated receptor γ (Pparγ) is a master regulator of adipogenesis. Chronic pathologies such as obesity, cardiovascular diseases, and diabetes involve the dysfunction of this transcription factor. Here, we generated a zebrafish mutant in pparγ (KO) with CRISPR/Cas9 technology and revealed its regulatory network. We uncovered the hepatic phenotypes of these male and female KO, and then the male wild-type zebrafish (WT) and KO were fed with a high-fat (HF) or standard diet (SD). We next conducted an integrated analyze of the proteomics and phosphoproteomics profiles. Compared with WT, the KO showed remarkable hyalinization and congestion lesions in the liver of males. Strikingly, pparγ deletion protected against the influence of high-fat diet feeding on lipid deposition in zebrafish. Some protein kinases critical for lipid metabolism, including serine/threonine-protein kinase TOR (mTOR), ribosomal protein S6 kinase (Rps6kb1b), and mitogen-activated protein kinase 14A (Mapk14a), were identified to be highly phosphorylated in KO based on differential proteome and phosphoproteome analysis. Our study supplies a pparγ deletion animal model and provides a comprehensive description of pparγ-induced expression level alterations of proteins and their phosphorylation, which are vital to understand the defective lipid metabolism risks posed to human health.

Preventive Impact of Long-Term Ingestion of Chestnut Honey on Glucose Disorders and Neurodegeneration in Obese Mice

The purpose of the present study was to evaluate the impact of long-term honey ingestion on metabolic disorders and neurodegeneration in mice fed a high-fat diet (HFD). Three groups of mice were fed with a standard diet (STD), HFD or HFD supplemented with honey (HFD-H) for 16 weeks. Biochemical, histological, Western blotting, RT-PCR and Profiler PCR array were performed to assess metabolic parameters, peripheral and central insulin resistance and neurodegeneration. Daily honey intake prevented the HFD-induced glucose dysmetabolism. In fact, it reduced plasma fasting glucose, insulin and leptin concentrations and increased adiponectin levels. It improved glucose tolerance, insulin sensitivity and HOMA index without affecting plasma lipid concentration. HFD mice showed a significantly higher number of apoptotic nuclei in the superficial and deep cerebral cortex, upregulation of Fas-L, Bim and P27 (neuronal pro-apoptotic markers) and downregulation of Bcl-2 and BDNF (anti-apoptotic factors) in comparison with STD- and HFD-H mice, providing evidence for honey neuroprotective effects. PCR-array analysis showed that long-term honey intake increased the expression of genes involved in insulin sensitivity and decreased genes involved in neuroinflammation or lipogenesis, suggesting improvement of central insulin resistance. The expressions of p-AKT and p-GSK3 in HFD-H mice, which were decreased and increased, respectively, in HFD mouse brain, index of central insulin resistance, were similar to STD animals supporting the ability of regular honey intake to protect brain neurons from insulin resistance. In conclusion, the present results provide evidence for the beneficial preventative impact of regular honey ingestion on neuronal damage caused by HFD.

Synaptic Protein Phosphorylation Networks Are Associated With Electroacupuncture-Induced Circadian Control in the Suprachiasmatic Nucleus

Phosphorylation is one of the most important posttranslational modifications and regulates the physiological process. While recent studies highlight a major role of phosphorylation in the regulation of sleep–wake cycles to a lesser extent, the phosphoproteome in the suprachiasmatic nucleus (SCN) is not well-understood. Herein, we reported that the EA treatment elicits partial reparation of circadian rhythmicity when mice were exposure to constant darkness for long time. We investigated the effects of EA on circadian rhythms in constant darkness between EA stimulation and free-running control. Next, mass spectrometry–based phosphoproteome was utilized to explore the molecular characteristics of EA-induced phosphorylation modification in the SCN. A total of 6,192 distinct phosphosites on 2,488 proteins were quantified. Functional annotation analysis and protein–protein interaction networks demonstrated the most significant enriched phosphor-proteins and phosphosites involved in postsynapse and glutamatergic synapse. The current data indicated that most of the altered molecules are structural proteins. The target proteins, NMDAR and CAMK2, were selected for verification, consistent with the results of LC–MS/MS. These findings revealed a complete profile of phosphorylation modification in response to EA.

Involvement of miR-3180-3p and miR-4632-5p in palmitic acid-induced insulin resistance

Insulin resistance is defined as a failure to trigger the activation of the PI3K-AKT pathway by normal levels of insulin; therefore, it is well linked to metabolic disorders. Although multiple mechanisms contribute to insulin resistance, one major cause is elevated concentrations of plasma free fatty acids, which are known to suppress insulin signaling. However, the underlying mechanism is still elusive. Here, we found that palmitic acid increased the expression of two miRNAs, miR-3180-3p and miR-4632-5p, in HepG2 cells. Transfection of HepG2 cells with miR-3180-3p or miR-4632-5p reduced insulin-induced activation of the PI3K-AKT pathway. Moreover, palmitic acid or two miRNAs inhibited insulin-induced phosphorylation of Tyr612 on IRS-1 without affecting insulin receptor activation. Therefore, two miRNAs are suggested to be involved in palmitic acid-induced insulin resistance through suppression of insulin-induced IRS-1 phosphorylation. Identification of miR-3180-3p and miR-4632-5p targets could provide valuable information for the development of therapeutic drugs for type 2 diabetes.

Obesity-associated deterioration of the hippocampus is partially restored after weight loss

OBJECTIVE

Obesity is a multidimensional condition that is treatable by the restoration of a lean phenotype; however, some obesity-related outcomes may persist after weight normalization. Among the organs of the human body, the brain possesses a relatively low regenerative capacity and could retain perturbations established as a result of developmental obesity. Calorie restriction (CR) or a restricted ketogenic diet (KD) are successfully used as weight loss approaches, but their impact on obesity-related effects in the brain have not been previously evaluated.

METHODS

We performed a series of experiments in a rat model of developmental obesity induced by a 12-week cafeteria diet, followed by CR to implement weight loss. First, we assessed the impact of obesity on neurogenesis (BrdU incorporation into the hippocampus), cognitive function (water maze), and concomitant changes in hippocampal protein expression (GC/MS-MS, western blot). Next, we repeated these experiments in a rat model of weight loss induced by CR. We also measured mitochondrial enzyme activity in rats after weight loss during the fed or fasting state. This study was extended by additional experiments with restricted KD used as a weight loss approach in order to compare the efficacy of two different nutritional interventions used in the treatment of obesity on hippocampal functions. By using a modified version of the water maze we evaluated cognitive abilities in rats subjected to weight loss by CR or a restricted KD.

RESULTS

In this study, obesity affected metabolic processes, upregulated hippocampal NF-κB, and induced proteomic differences which were associated with impaired cognition and neurogenesis. Weight loss improved neurogenesis and enhanced cognition. While the expression pattern of some proteins persisted after weight loss, most of the changes appeared de novo revealing metabolic adjustment by overactivation of citrate synthase and downregulation of ATP synthase. As a consequence of fasting, the activity of these enzymes indicated hippocampal adaptation to negative energy balance during the weight loss phase of CR. Moreover, the effects on cognitive abilities measured after weight loss were negatively correlated with the animal weight measured at the final stage of weight gain. This was alleviated by KD, which improved cognition when used as a weight loss approach.

CONCLUSIONS

The study shows that cognition and mitochondrial metabolism in the hippocampus are affected by CR- or KD-induced weight loss.

Obesogenic Diets Cause Alterations on Proteins and Theirs Post-Translational Modifications in Mouse Brains

Obesity constitutes a major global health threat and is associated with a variety of diseases ranging from metabolic and cardiovascular disease, cancer to neurodegeneration. The hallmarks of neurodegeneration include oxidative stress, proteasome impairment, mitochondrial dysfunction and accumulation of abnormal protein aggregates as well as metabolic alterations. As an example, in post-mortem brain of patients with Alzheimer’s disease (AD), several studies have reported reduction of insulin, insulin-like growth factor 1 and insulin receptor and an increase in tau protein and glycogen-synthase kinase-3β compared to healthy controls suggesting an impairment of metabolism in the AD patient’s brain. Given these lines of evidence, in the present study we investigated brains of mice treated with 2 obesogenic diets, high-fat diet (HFD) and high-glycaemic diet (HGD), compared to mice fed with a standard diet (SD) employing a quantitative mass spectrometry-based approach. Moreover, post-translational modified proteins (phosphorylated and N-linked glycosylated) were studied. The aim of the study was to identify proteins present in the brain that are changing their expression based on the diet given to the mice. We believed that some of these changes would highlight pathways and molecular mechanisms that could link obesity to brain impairment. The results showed in this study suggest that, together with cytoskeletal proteins, mitochondria and metabolic proteins are changing their post-translational status in brains of obese mice. Specifically, proteins involved in metabolic pathways and in mitochondrial functions are mainly downregulated in mice fed with obesogenic diets compared to SD. These changes suggest a reduced metabolism and a lower activity of mitochondria in obese mice. Some of these proteins, such as PGM1 and MCT1 have been shown to be involved in brain impairment as well. These results might shed light on the well-studied correlation between obesity and brain damage. The results presented here are in agreement with previous findings and aim to open new perspectives on the connection between diet-induced obesity and brain impairment.

Obese Animals as Models for Numerous Diseases: Advantages and Applications

With the advances in obesity research, a variety of animal models have been developed to investigate obesity pathogenesis, development, therapies and complications. Such obese animals would not only allow us to explore obesity but would also represent models to study diseases and conditions that develop with obesity or where obesity represents a risk factor. Indeed, obese subjects, as well as animal models of obesity, develop pathologies such as cardiovascular diseases, diabetes, inflammation and metabolic disorders. Therefore, obese animals would represent models for numerous diseases. Although those diseases can be induced in animals by chemicals or drugs without obesity development, having them developed as consequences of obesity has numerous advantages. These advantages include mimicking natural pathogenesis processes, using diversity in obesity models (diet, animal species) to study the related variabilities and exploring disease intensity and reversibility depending on obesity development and treatments. Importantly, therapeutic implications and pharmacological tests represent key advantages too. On the other hand, obesity prevalence is continuously increasing, and, therefore, the likelihood of having a patient suffering simultaneously from obesity and a particular disease is increasing. Thus, studying diverse diseases in obese animals (either induced naturally or developed) would allow researchers to build a library of data related to the patterns or specificities of obese patients within the context of pathologies. This may lead to a new branch of medicine specifically dedicated to the diseases and care of obese patients, similar to geriatric medicine, which focuses on the elderly population.

Slc1a3-2A-CreERT2 mice reveal unique features of Bergmann glia and augment a growing collection of Cre drivers and effectors in the 129S4 genetic background

Genetic variation is a primary determinant of phenotypic diversity. In laboratory mice, genetic variation can be a serious experimental confounder, and thus minimized through inbreeding. However, generalizations of results obtained with inbred strains must be made with caution, especially when working with complex phenotypes and disease models. Here we compared behavioral characteristics of C57Bl/6—the strain most widely used in biomedical research—with those of 129S4. In contrast to 129S4, C57Bl/6 demonstrated high within-strain and intra-litter behavioral hyperactivity. Although high consistency would be advantageous, the majority of disease models and transgenic tools are in C57Bl/6. We recently established six Cre driver lines and two Cre effector lines in 129S4. To augment this collection, we genetically engineered a Cre line to study astrocytes in 129S4. It was validated with two Cre effector lines: calcium indicator gCaMP5g-tdTomato and RiboTag—a tool widely used to study cell type-specific translatomes. These reporters are in different genomic loci, and in both the Cre was functional and astrocyte-specific. We found that calcium signals lasted longer and had a higher amplitude in cortical compared to hippocampal astrocytes, genes linked to a single neurodegenerative disease have highly divergent expression patterns, and that ribosome proteins are non-uniformly expressed across brain regions and cell types.

Cerebrocortical proteome profile of female rats subjected to the western diet and chronic social stress

The energy-dense western diet significantly increases the risk of obesity, type 2 diabetes, cardiovascular episodes, stroke, and cancer. Recently more attention has been paid to the contribution of an unhealthy lifestyle on the development of central nervous system disorders. Exposure to long-lasting stress is one of the key lifestyle modifications associated with the increased prevalence of obesity and metabolic diseases. The main goal of the present study was to verify the hypothesis that exposure to chronic stress modifies alterations in the brain proteome induced by the western diet. Female adult rats were fed with the prepared chow reproducing the human western diet and/or subjected to chronic stress induced by social instability for 6 weeks. A control group of lean rats were fed with a standard diet. Being fed with the western diet resulted in an obese phenotype and induced changes in the serum metabolic parameters. The combination of the western diet and chronic stress exposure induced more profound changes in the rat cerebrocortical proteome profile than each of these factors individually. The down-regulation of proteins involved in neurotransmitter secretion (Rph3a, Snap25, Syn1) as well as in learning and memory processes (Map1a, Snap25, Tnr) were identified, while increased expression was detected for 14-3-3 protein gamma (Ywhag) engaged in the modulation of the insulin-signaling cascade in the brain. An analysis of the rat brain proteome reveals important changes that indicate that a combination of the western diet and stress exposure may lead to impairments of neuronal function and signaling.

Regular Intake of Pistachio Mitigates the Deleterious Effects of a High Fat-Diet in the Brain of Obese Mice

Obesity has been associated with neurodegeneration and cognitive dysfunctions. Recent data showed that pistachio consumption is able to prevent and ameliorate dyslipidemia, hepatic steatosis, systemic and adipose tissue inflammation in mice fed a high-fat diet (HFD). The present study investigated the neuroprotective effects of pistachio intake in HFD mice. Three groups of mice were fed a standard diet (STD), HFD, or HFD supplemented with pistachio (HFD-P) for 16 weeks. Metabolic parameters (oxidative stress, apoptosis, and mitochondrial dysfunction) were analyzed by using specific assays and biomarkers. The pistachio diet significantly reduced the serum levels of triglycerides and cholesterol in the HFD model. No difference was observed in the index of insulin resistance between HFD and HFD-P. A higher number of fragmented nuclei were found in HFD cerebral cortex compared to STD and HFD-P. A decrease in reactive oxygen species, singlet oxygen and phosphorylated extracellular signal-regulated kinase, and an increase of superoxide dismutase 2 and heme oxygenase expression were found in the brains of the HFD-P samples compared to HFD. Furthermore, the impaired mitochondrial function found in HFD brain was partially recovered in HFD-P mice. These results suggest that the regular intake of pistachio may be useful in preventing obesity-related neurodegeneration, being able to reduce both metabolic and cellular dysfunctions.

Natural Compounds as Beneficial Antioxidant Agents in Neurodegenerative Disorders: A Focus on Alzheimer's Disease

The positive role of nutrition in chronic neurodegenerative diseases (NDs) suggests that dietary interventions represent helpful tools for preventing NDs. In particular, diets enriched with natural compounds have become an increasingly attractive, non-invasive, and inexpensive option to support a healthy brain and to potentially treat NDs. Bioactive compounds found in vegetables or microalgae possess special properties able to counteract oxidative stress, which is involved as a triggering factor in neurodegeneration. Here, we briefly review the relevant experimental data on curcuminoids, silymarin, chlorogenic acid, and compounds derived from the microalga Aphanizomenon flos aquae (AFA) which have been demonstrated to possess encouraging beneficial effects on neurodegeneration, in particular on Alzheimer's disease models.

Obesity associated with coal ash inhalation triggers systemic inflammation and oxidative damage in the hippocampus of rats

People with large amounts of adipose tissue are more vulnerable and more likely to develop diseases where oxidative stress and inflammation play a pivotal role, than persons with a healthy weight. Atmospheric contamination is a reality to which a large part of the worldwide population is exposed. Half of today's global electrical energy is derived from coal. Each organism, in its complexity, responds in different ways to dietary compounds and air pollution. The objective of this study was to investigate the effects of obesity and coal ash inhalation within the parameters of oxidative damage and inflammation in different regions of the brain of rats. A diet containing high-fat concentration was administered chronically to rats, along with exposure to coal ash, simulating the contamination that occurs daily throughout human life. High-resolution transmission electron microscopy was performed to identify the particles present in coal ash samples. Our results demonstrated that obese rats exposed to coal ash inhalation were more affected by oxidative damage with subsequent systemic inflammation in the hippocampus. Since there is an inflammatory predisposition caused by obesity, the inhalation of nanoparticles increases the levels of free radicals, resulting in systemic inflammation and oxidative damage, which can lead to chronic neurodegeneration.