Project description:To understand the transcriptional effect of fasting and feeding a ketogenic diet on mouse CNS astrocytes, we performed translating ribosomal affinity purification (TRAP) of mRNAs immunoprecipitated from hippocampus. TRAP mice express a ribosomal epitope tag upon Cre-induced recombination that can be immunoprecipitated following activation. We measured the abundance of actively translating mRNAs from a ribosomal pull-down that came from adult astrocyte (Aldh1l1-Cre)-specific TRAP mice that were subjected to one of three dietary conditions: four weeks of normal chow diet, four weeks of ketogenic diet (high-fat, low-carbohydrate)43, or an 18-hour fast. Immediately following the respective diets, forebrain and hippocampus was harvested from all groups, ribosomes were immunoprecipitated, and actively translating mRNAs in the ribosomes were purified.
Project description:To maintain homeostasis, the body including the brain reprograms its metabolism in response to altered nutrition or disease. However, the consequences of these challenges for the energy metabolism of the different brain cell types remain unknown. Here, we generated a proteome atlas of the major CNS cell types from young and adult mice, after feeding the therapeutically relevant low-carbohydrate, high-fat ketogenic diet (KD) and during neuroinflammation. Under steady-state conditions, CNS cell types prefer distinct modes of energy metabolism. Surprisingly, the comparison with KD revealed distinct cell type-specific strategies to manage the altered availability of energy metabolites. Astrocytes and neurons but not oligodendrocytes demonstrated metabolic plasticity. Unexpectedly, inflammatory demyelinating disease changed the neuronal metabolic signature in a similar direction as KD. Together, these findings highlight the importance of the metabolic crosstalk between CNS cells and between the periphery and the brain to manage altered nutrition and neurological disease.
Project description:Kabuki syndrome is a Mendelian intellectual disability syndrome caused by mutations in either of two genes (KMT2D and KDM6A) involved in chromatin accessibility. We previously showed that an agent that promotes chromatin opening, the histone deacetylase inhibitor (HDACi) AR-42, ameliorates the deficiency of adult neurogenesis in the granule cell layer of the dentate gyrus, and rescues hippocampal memory defects in a mouse model of Kabuki syndrome (Kmt2d+/βGeo). Unlike a drug, a dietary intervention could be quickly transitioned to the clinic. Therefore, we have explored whether treatment with a ketogenic diet could lead to a similar rescue through increased amounts of beta-hydroxybutyrate, an endogenous HDACi. Here, we report that a ketogenic diet in Kmt2d+/βGeo mice modulates H3ac and H3K4me3 in the granular cell layer, with concomitant rescue of both the neurogenesis defect and hippocampal memory abnormalities seen in Kmt2d+/βGeo mice; similar effects on neurogenesis were observed upon exogenous administration of beta-hydroxybutyrate. These data suggests that dietary modulation of epigenetic modifications through elevation of beta-hydroxybutyrate may provide a feasible strategy to treat the intellectual disability seen in Kabuki syndrome and related disorders. We used microarrays to query global gene expression changes in the hippocampus of wild type and Kmt2d+/βGeo (Kabuki syndrome model) mice on a regular diet to identify specific gene expression abnormalities in the hippocampus of the Kabuki syndrome mouse model.
Project description:The ketogenic diet has long been used to treat epilepsy, but its mechanism is not yet clearly understood. To explore the potential mechanism, the changes in gene expression induced by the ketogenic diet in the rat kainic acid (KA) epilepsy model were analyzed. Two-condition experiment, Normal diet-fed rat brain vs. Ketogenic diet-fed rat brain. Duplicate per array
Project description:Specific pathogen free wild-type C57Bl/6 male mice fed ketogenic diet (Bio-Serv AIN-76-A) for 4 weeks Keywords: RNA Expression Array Hearts from 12 week-old mice that were maintained on a standard polysacchardide-rich chow until the age of 8 weeks, at which time they were switched to a ketogenic diet (ad libitum) and maintained for 4 additional weeks prior to collection of tissues
Project description:To maintain homeostasis, the body including the brain reprograms its metabolism in response to altered nutrition or disease. However, the consequences of these challenges for the energy metabolism of the different brain cell types remain unknown. Here, we generated a proteome atlas of the major CNS cell types from young and adult mice, after feeding the therapeutically relevant low-carbohydrate, high-fat ketogenic diet (KD) and during neuroinflammation. Under steady-state conditions, CNS cell types prefer distinct modes of energy metabolism. Surprisingly, the comparison with KD revealed distinct cell type-specific strategies to manage the altered availability of energy metabolites. Astrocytes and neurons but not oligodendrocytes demonstrated metabolic plasticity. Unexpectedly, inflammatory demyelinating disease changed the neuronal metabolic signature in a similar direction as KD. Together, these findings highlight the importance of the metabolic crosstalk between CNS cells and between the periphery and the brain to manage altered nutrition and neurological disease.
Project description:Pyruvate has two major fates upon entry into mitochondria, the oxidative decarboxylation to acetyl-CoA or the biotin-dependent carboxylation to oxaloacetate via pyruvate carboxylase (Pcx). Here we have generated mice with a liver specific knockout of Pcx to understand its role in hepatic mitochondrial metabolism under disparate physiological states including a 24 hour fast, as well as ketogenic and high fat diets. These data ultimately show the requirement of Pcx-mediated anapleorsis in the liver under disparate metabolic conditions.
Project description:Background Kabuki syndrome (KS) is a genetic disorder caused by DNA mutations in KMT2D, a lysine methyltransferase that methylates histones and other proteins, and therefore modifies chromatin structure and subsequent gene expression. Ketones, derived from the ketogenic diet, are histone deacetylase inhibitors that can ‘open’ chromatin and encourage gene expression. Preclinical studies have shown that the ketogenic diet rescues hippocampal memory neurogenesis in mice with KS via the epigenetic effects of ketones. Methods Single-cell RNA sequencing and mass spectrometry-based proteomics were used to explore molecular mechanisms of disease in individuals with KS (n=4) versus controls (n=4). Findings Pathway enrichment analysis indicated that loss of function mutations in KMT2D are associated with ribosomal protein dysregulation at an RNA and protein level in individuals with KS (FDR <0.05). Cellular proteomics also identified immune dysregulation and increased abundance of other lysine modification and histone binding proteins, representing a potential compensatory mechanism. A 12-year-old boy with KS, suffering from recurrent episodes of cognitive decline, exhibited improved cognitive function and neuropsychological assessment performance after 12 months on the ketogenic diet, with concomitant improvement in transcriptomic ribosomal protein dysregulation.
Project description:Pyruvate has two major fates upon entry into mitochondria, the oxidative decarboxylation to acetyl-CoA or the biotin-dependent carboxylation to oxaloacetate via pyruvate carboxylase (Pcx). Here we have generated mice with a liver specific knockout of pyruvate carboxylase (PcxL-/-) to understand the role of Pcx in hepatic mitochondrial metabolism under disparate physiological states. PcxL-/- mice exhibited a deficit in hepatic gluconeogenesis as expected but were able to maintain systemic euglycemia following a 24hr fast and enhanced ketogenesis. Feeding a high fat diet to PcxL-/- mice resulted in animals that were resistant to glucose intolerance without affecting body weight. However, PcxL-/- mice fed a ketogenic diet for 1 week became severely hypoglycemic, demonstrating a requirement for hepatic Pcx for long term glycemia under carbohydrate limited diets. Loss of Pcx was associated with an induction of protein acetylation in PcxL-/- mice regardless of physiologic state. Furthermore, liver acetyl-proteomics revealed a biased induction in mitochondrial lysine acetylation. These data show that Pcx is important for maintaining the proper balance of pyruvate metabolism between oxidative and anaplerotic pathways.