Project description:Cancer-augmented lactogenesis has been described by the Warburg effect, and is associated with several major hallmarks of neoplasia. However, the non-metabolic functions of elevated lactate in physiology and disease remain unknown. Here we report histone lysine lactylation as a new type of epigenetic mechanism and as a functional destination for lactate. Histone lactylation is induced under glycolytic conditions such as hypoxia and M1 macrophage polarization. In the late phase of M1 macrophage polarization, increases in histone lactylation but not acetylation mark M2-like genes for activation. Our findings suggest a feedback mechanism of the innate immune system to switch from proinflammation to resolution through histone Kla-associated gene expression. This mechanism is implemented by the coopted function of lactate and histone lactylation in metabolism and epigenetics. Together, our study opens a new avenue for understanding function of lactate and glycolysis underlined diverse pathophysiological conditions.
Project description:Eight types of short-chain Lys acylations have recently been identified on histones: propionylation, butyrylation, 2-hydroxyisobutyrylation, succinylation, malonylation, glutarylation, crotonylation and ?-hydroxybutyrylation. Emerging evidence suggests that these histone modifications affect gene expression and are structurally and functionally different from the widely studied histone Lys acetylation. In this Review, we discuss the regulation of non-acetyl histone acylation by enzymatic and metabolic mechanisms, the acylation 'reader' proteins that mediate the effects of different acylations and their physiological functions, which include signal-dependent gene activation, spermatogenesis, tissue injury and metabolic stress. We propose a model to explain our present understanding of how differential histone acylation is regulated by the metabolism of the different acyl-CoA forms, which in turn modulates the regulation of gene expression.
Project description:The Warburg effect, which originally described increased production of lactate in cancer, is associated with diverse cellular processes such as angiogenesis, hypoxia, polarization of macrophages and activation of T cells. This phenomenon is intimately linked to several diseases including neoplasia, sepsis and autoimmune diseases1,2. Lactate, which is converted from pyruvate in tumour cells, is widely known as an energy source and metabolic by-product. However, its non-metabolic functions in physiology and disease remain unknown. Here we show that lactate-derived lactylation of histone lysine residues serves as an epigenetic modification that directly stimulates gene transcription from chromatin. We identify 28 lactylation sites on core histones in human and mouse cells. Hypoxia and bacterial challenges induce the production of lactate by glycolysis, and this acts as a precursor that stimulates histone lactylation. Using M1 macrophages that have been exposed to bacteria as a model system, we show that histone lactylation has different temporal dynamics from acetylation. In the late phase of M1 macrophage polarization, increased histone lactylation induces homeostatic genes that are involved in wound healing, including Arg1. Collectively, our results suggest that an endogenous 'lactate clock' in bacterially challenged M1 macrophages turns on gene expression to promote homeostasis. Histone lactylation thus represents an opportunity to improve our understanding of the functions of lactate and its role in diverse pathophysiological conditions, including infection and cancer.
Project description:Here we report the identification and verification of a ?-hydroxybutyrate-derived protein modification, lysine ?-hydroxybutyrylation (Kbhb), as a new type of histone mark. Histone Kbhb marks are dramatically induced in response to elevated ?-hydroxybutyrate levels in cultured cells and in livers from mice subjected to prolonged fasting or streptozotocin-induced diabetic ketoacidosis. In total, we identified 44 histone Kbhb sites, a figure comparable to the known number of histone acetylation sites. By ChIP-seq and RNA-seq analysis, we demonstrate that histone Kbhb is a mark enriched in active gene promoters and that the increased H3K9bhb levels that occur during starvation are associated with genes upregulated in starvation-responsive metabolic pathways. Histone ?-hydroxybutyrylation thus represents a new epigenetic regulatory mark that couples metabolism to gene expression, offering a new avenue to study chromatin regulation and diverse functions of ?-hydroxybutyrate in the context of important human pathophysiological states, including diabetes, epilepsy, and neoplasia.
Project description:The transcriptome, proteome and metabolome of 16 S.cerevisiae backgrounds, combinatorially perturbed in HIS3, LEU2, URA3 and MET15strains are compared. The project was jointly supervised by Kathryn Lilley and Markus Ralser. Transcriptome data has been deposited at ArrayExpress under accession <a href="http://www.ebi.ac.uk/microarray-as/aer/result?queryFor=Experiment&eAccession=E-MTAB-3991">E-MTAB-3991</a>. Metabolome data has been deposited at Metabolights with accession number <a href="http://www.ebi.ac.uk/metabolights/MTBLS168">MTBLS168</a>. The regulation of gene expression in response to nutrient availability is fundamental to the genotype–phenotype relationship. The metabolic–genetic make-up of the cell, as reflected in auxotrophy, is hence likely to be a determinant of gene expression. Here, we address the importance of the metabolic–genetic background by monitoring transcriptome, proteome and metabolome in a repertoire of 16 Saccharomyces cerevisiae laboratory backgrounds, combinatorially perturbed in histidine, leucine, methionine and uracil biosynthesis. The metabolic background affected up to 85% of the coding genome. Suggesting widespread confounding, these transcriptional changes show, on average, 83% overlap between unrelated auxotrophs and 35% with previously published transcriptomes generated for non-metabolic gene knockouts. Background-dependent gene expression correlated with metabolic flux and acted, predominantly through masking or suppression, on 88% of transcriptional interactions epistatically. As a consequence, the deletion of the same metabolic gene in a different background could provoke an entirely different transcriptional response. Propagating to the proteome and scaling up at the metabolome, metabolic background dependencies reveal the prevalence of metabolism-dependent epistasis at all regulatory levels. Urging a fundamental change of the prevailing laboratory practice of using auxotrophs and nutrient supplemented media, these results reveal epistatic intertwining of metabolism with gene expression on the genomic scale.
Project description:Epigenetics and Alternative Splicing are both critical mechanisms guiding gene expression. Several studies have demonstrated that epigenetic marks can influence alternative splicing decisions, but less is known about how alternative splicing may impact epigenetics. Here, we demonstrate that several genes encoding histone modifying enzymes are alternatively spliced downstream of T cell activation signaling pathways, including HDAC7, a gene previously implicated in controlling gene expression programs and differentiation in T cells. Using CRISPR-Cas9 gene editing and cDNA expression, we show that differential inclusion of HDAC7 exon 9 controls the interaction of HDAC7 with protein chaperones with resulting impact on histone modifications and gene expression. Notably, the long isoform, which is favored upon JNK signaling, promotes expression of several critical T cell surface proteins including CD3, CD28, CD69. Thus, we demonstrate that alternative splicing of HDAC7 has a global impact on epigenetics and gene expression, and may contribute to T cell regulation.