Project description:Aging is the primary risk factor for most neurodegenerative diseases, including Alzheimer's disease. Major hallmarks of brain aging include neuroinflammation/immune activation and reduced neuronal health/function. These processes contribute to cognitive dysfunction (a key risk factor for Alzheimer's disease), but their upstream causes are incompletely understood. Age-related increases in transposable element (TE) transcripts might contribute to reduced cognitive function with brain aging, as the reverse transcriptase inhibitor 3TC reduces inflammation in peripheral tissues and TE transcripts have been linked with tau pathology in Alzheimer's disease. However, the effects of 3TC on cognitive function with aging have not been investigated. Here, in support of a role for TE transcripts in brain aging/cognitive decline, we show that 3TC: (a) improves cognitive function and reduces neuroinflammation in old wild-type mice; (b) preserves neuronal health with aging in mice and Caenorhabditis elegans; and (c) enhances cognitive function in a mouse model of tauopathy. We also provide insight on potential underlying mechanisms, as well as evidence of translational relevance for these observations by showing that TE transcripts accumulate with brain aging in humans, and that these age-related increases intersect with those observed in Alzheimer's disease. Collectively, our results suggest that TE transcript accumulation during aging may contribute to cognitive decline and neurodegeneration, and that targeting these events with reverse transcriptase inhibitors like 3TC could be a viable therapeutic strategy.
Project description:Age is the primary risk factor for many chronic diseases and cognitive decline during brain aging may increase dementia risk. Hallmarks of brain aging including neuronal dysfunction and glial contribute to reduced cognitive function, and there is a persistent lack of effective treatments. Bioactive plant compounds called “nutraceuticals” can target age-related cellular processes and may protect cognitive function. Apigenin is a flavone found in plants such as chamomile and can inhibit hallmarks of aging such as cellular senescence, mitochondrial dysfunction, and impaired proteostasis. However, the underlying mechanisms of apigenin in the brain are not fully understood. Here, we characterized brain transcriptome changes in young and old mice given apigenin in drinking water and examined potential mechanisms in human astrocytes. Consistent with previous studies, we observed improved novel object recognition in old mice treated with apigenin versus old controls. Transcriptome analyses in old controls found differentially expressed genes related to immune responses, inflammation, and cytokine regulation versus young. Fewer differences were observed in old apigenin-treated versus old controls, but these changes were related to development, behavior, and antiviral responses. The majority of upregulated genes in old mice were downregulated with apigenin treatment and associated with immune responses. Similarly, the genes that were reduced with aging, but increased in old apigenin-treated mice were related to pathways important for neurological function/disease, cellular maintenance, and homeostatic signaling. We also found that glial cells drove the majority of the transcriptome differences with aging and apigenin-treatment. To explore the mechanism of action for apigenin in glial cells, we treated replicatively aged astrocytes with apigenin and observed reduced markers of inflammation and cellular senescence. Collectively, our data support the role of apigenin as a protector of cognitive and neuronal function protectant through the suppression of neuroinflammatory genes and proteins and may be especially important in non-neuronal cells.
Project description:Radiotherapy is an important therapeutic option for the treatment of primary and metastatic brain tumors, and there is increasing concern about the side effects associated with it as survival time after treatment increases. By far, cognitive dysfunction is the most common radiation-induced central nervous system injury. Studies have shown that the hippocampus is involved in radiation-induced cognitive dysfunction. We constructed a model of radiation-induced cognitive dysfunction by irradiating the whole brain of one-month-old rats with 20 Gy, and analyzed the expression profiles in the hippocampus of rats with radiation-induced cognitive dysfunction using single-cell RNA sequencing (scRNA-seq).
Project description:BALB/c mice are susceptible to proteoglycan (PG) aggrecan-induced arthritis (PGIA), and the absence of TSG-6 further increases susceptibility and local inflammatory reactions, including neutrophil invasion into the joints. To gain insight into the mechanisms of TSG-6 action, synovial fibroblasts were isolated from wild-type and TSG-6-KO mice, cultured and exposed to various agents affecting either the TSG-6 expression and/or modify the intracellular function of TSG-6. In the present microarray studies, we have identified differences in gene expression by fibroblasts isolated from wild-type or TSG-6-KO mice Keywords: Genetic modification In this study we compared the gene expression profile of 42 fibroblast cultures from mouse synovial samples. Fifteen samples were wild-type and 27 samples were TSG-6 knockout. In these two genotype groups fibroblasts were treated with TNFa, LPS, TSG-6, HA, or HA+TSG-6, and were compared to untreated samples in the same genotype group. We also compared the same treatments between KO and WT.
Project description:Kurozu is a traditional Japanese rice vinegar. During fermentation and aging of the Kurozu liquid in an earthenware jar over 1 year, solid residue called Kurozu Moromi is produced. In the present study, we evaluated whether concentrated Kurozu or Kurozu Moromi could ameliorate cognitive dysfunction in the senescence accelerated P8 mouse. Senescence accelerated P8 mice were fed 0.25% (w/w) concentrated Kurozu or 0.5% (w/w) Kurozu Moromi for 4 or 25 weeks. Kurozu suppressed cognitive dysfunction and amyloid accumulation in the brain, while Kurozu Moromi showed a tendency to ameliorate cognitive dysfunction, but the effect was not significant. We hypothesize that concentrated Kurozu has an antioxidant effect, however, the level of lipid peroxidation in the brain did not differ in senescence accelerated P8 mice. DNA microarray analysis indicated that concentrated Kurozu increased HSPA1A mRNA expression, a protein that prevents protein misfolding and aggregation. The increase in HSPA1A expression by Kurozu was confirmed using quantitative real-time PCR and immunoblotting methods. Therefore, the suppression of amyloid accumulation by concentrated Kurozu may be associated with HSPA1A induction. However, concentrated Kurozu could not increase HSPA1A expression in mouse primary neurons, suggesting it may not directly affect neurons. Ten-times concentrated Kurozu (CK) was made from Kurozu liquid (Sakamoto Kurozu, Fukuyama, Kagoshima, Japan) by repeated vacuum distillation. The CK diet included 0.25% (w/w) CK in CE-2 basic rodent diet (Nihon CLEA, Tokyo, Japan). Senescence resistance (R1) and senescence accelerated P8 (P8) mice were purchased from Japan SLC (Shizuoka, Japan). Mice were housed at 25±2°C with 55±10% humidity on a 12-h light/dark cycle (lighting time 08:00-20:00). All mice were housed in independent cages and had free access to food and water. All procedures were compliant with the guidelines of the Kagoshima University Animal Ethics Committee (A10030). Ten-week old R1 mice (n=16) were fed a control CE2 diet and P8 mice were divided into three groups as follows: control CE2 diet group (n=9), KM diet group (n=9) or CK diet group (n=9). Feeding of the experimental diet started from 12 weeks of age until sacrificed. All mice were sacrificed under anesthesia at 17 weeks old (4 months old). The left side of the hippocampus region was excised from brains of 4 mice selected at random in each group, and then subjected to microarray analysis.
Project description:Elderly patients are apt to cognitive impairment and memory loss after surgical operations. This perioperative cerebral damage named postoperative cognitive dysfunction (POCD) is profoundly affected by anesthesia. N6-methyladenosine (m6A) RNA methylation as a widely-studied epigenetic modification to regulate gene expression, however, is never studied in POCD. Initially, fifty 40-week-old outbred female C57BL/6 mice were conducted Morris water maze test by EthoVision XT working system (Noldus, Netherlands) as manufacturer’s instructions. The escaping latent period of each mouse were recorded. Then Thirty mice were randomly selected and given 2% sevoflurane for 4 h in an automatic anesthetic chamber with size of 24 cm*12 cm*18 cm. After natural resuscitation, POCD and non-POCD mice were picked up based on the dynamics of escaping latent period. The other twenty mice received normal air were treated as negative control. Hippocampus were conducted RIP-seq for investigating m6A RNA methylation.
Project description:Proteoglycans containing link-domains modify the extracellular matrix (ECM) to regulate cellular homeostasis and can also sensitize tissues/organs to injury and stress. Hypoxic-Ischemic (H-I) injury disrupts cellular homeostasis by activating inflammation and attenuating regeneration and repair pathways. In the brain, the main component of the ECM is the glycosaminoglycan (GAG), Hyaluronic Acid (HA), but whether HA modifications of the ECM regulate cellular homeostasis and response to H-I injury is not known. In this report, employing both male and female mice, we demonstrate that link-domain containing proteoglycan, TNF-stimulated gene-6 (TSG-6), is active in the brain from birth onwards and differentially modifies ECM HA during discrete neurodevelopmental windows. ECM HA modification by TSG-6 enables it to serve as a developmental switch to regulate activity of the Hippo pathway effector protein, Yes Associated Protein 1 (YAP1) in the maturing brain and in response to H-I injury. Mice that lack TSG-6 expression display dysregulated expression of YAP1 targets, excitatory amino acid transporter 1 (EAAT1; GLAST) and 2 (EAAT2; GLT-1). Dysregulation of YAP1 activation in TSG-6-/- mice coincides with age- and sex-dependent sensitization of the brain to H-I injury such that 1-week-old neonates display an anti-inflammatory response in contrast to an enhanced pro-inflammatory injury reaction in 3-month-old adult males but not females. Our findings thus support that a key regulator of age- and sex-dependent H-I injury response in the mouse brain is modulation of the Hippo-YAP1 pathway by TSG-6 dependent ECM modifications.
Project description:BALB/c mice are susceptible to proteoglycan (PG) aggrecan-induced arthritis (PGIA), and the absence of TSG-6 further increases susceptibility and local inflammatory reactions, including neutrophil invasion into the joints. To gain insight into the mechanisms of TSG-6 action, synovial fibroblasts were isolated from wild-type and TSG-6-KO mice, cultured and exposed to various agents affecting either the TSG-6 expression and/or modify the intracellular function of TSG-6. In the present microarray studies, we have identified differences in gene expression by fibroblasts isolated from wild-type or TSG-6-KO mice Keywords: Genetic modification
Project description:Emerging findings suggest that compromised cellular bioenergetics and DNA repair contribute to the pathogenesis of Alzheimer's disease (AD), but their role in disease-defining pathology is unclear. We developed a DNA repair-deficient 3xTgAD/Polb+/- mouse that exacerbates major features of human AD including pTau pathologies, synaptic dysfunction, neuronal death and cognitive impairment. Here we report that 3xTgAD/Polb+/- mice have reduced cerebral NAD+/NADH ratio indicating impaired cerebral energy metabolism, which is normalized by nicotinamide riboside (NR) treatment. NR lessened pTau pathology in both 3xTgAD and 3xTgAD/Polb+/- mice, but had no impact on Abeta accumulation. NR-treated 3xTgAD/Polb+/- mice exhibited reduced DNA damage, neuroinflammation, apoptosis of hippocampal neurons, and increased activity of SIRT3 in the brain. NR improves cognitive function in multiple behavioral tests, and restored hippocampal synaptic plasticity in 3xTgAD mice and 3xTgAD/Polb+/- mice. In general, the deficits and the benefits of NR were greater in 3xTgAD/Polb+/- mice than in 3xTgAD mice. Our findings suggest a pivotal role for cellular NAD+ depletion upstream of neuroinflammation, pTau, DNA damage, synaptic dysfunction and neuronal degeneration in AD. Interventions that bolster neuronal NAD+ levels therefore have potential in AD.
Project description:Doxorubicin (Doxo) is a common chemotherapeutic reagent associated with mitochondrial dysfunction, DNA damage, and cognitive impairment in human cancer patients. The purpose of this study was to determine the transcriptional effects of Doxo on the brains of young mice. 4 month old C57B6/J male mice were injected with saline sham or 10mg/kg Doxo +/- MitoQ (a mitochondria-specific antioxidant). Hippocampi were harvested from these mice and RNA was isolated to perform polyA RNA-seq to profile gene expression.