Best Poster Awards – Metabolism Meets Epigenetics

In its first edition, the EMBO|EMBL Symposium: Metabolism Meets Epigenetics brought together 289 world-leading researchers who examined how metabolites and metabolic networks impact gene regulation, what their roles are in disease and how this opens novel therapeutic avenues.

In addition to the 21 invited speakers and 22 selected short talks, 142 posters were presented during the two poster sessions. Today we present three of the five award-winning posters decided by popular vote.

Citrate carrier links intermediate metabolism to histone acetylation upon ageing of mouse mesenchymal stem cells (MSCs)

PHOTO: Andromachi Pouikli

Authors: Andromachi Pouikli (1), Monika Maleszewska (2), Swati Parekh (1), Chrysa Nikopoulou (1), Maarouf Baghdadi (1), Linda Partridge (1), Peter Tessarz (1)

Chromatin and metabolism interact in a reciprocal manner; on one hand metabolism-related genes are subjected to epigenetic modifications, which regulate gene expression. On the other hand, intracellular metabolism provides metabolites which can serve as essential co-factors and substrates for chromatin-modifying enzymes, affecting their activity. Although, it is well established that the process of ageing is accompanied by changes in metabolism and by chromatin alterations, their interplay in this context remains still poorly understood. In this study we sought to determine how ageing impinges on the relationship between cellular metabolism and the epigenome, using mouse mesenchymal stem cells from the bone marrow (BM-MSCs). In brief, our data suggest that there is a strong and direct link between the metabolic and the epigenetic states of the cell, with ageing-driven changes in metabolism regulating gene transcription and BM-MSC’s stemness, via alterations of the chromatin structure. We conclude that physiological ageing elicits changes in metabolism, resulting in suppressed glycolysis and impaired lipid biogenesis. Moreover, we demonstrate that during ageing there are lower levels of histone acetylation, despite the higher acetyl-CoA levels. We provide a solid explanation for this apparent discrepancy, pointing to the impaired export of acetyl-CoA from mitochondria to the cytosol. Indeed, the protein levels of the citrate carrier Slc25a1 decrease dramatically upon ageing. Using inhibition and supplementation experiments we provide a causal relationship between Slc25a1 function and the levels of histone acetylation, which directly influence chromatin accessibility and plasticity. Collectively, our data establish a tight, age-dependent connection between metabolism, epigenome and stemness and identify citrate carrier as the responsible protein for the mitochondrial-nuclear communication.

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(1) Max Planck Institute for Biology of Ageing, Germany, (2) Personalis Inc, Germany

Epigenetics meets metabolism through histone acetyltransferase NAA40

PHOTO: Christina Demetriadou

Authors: Christina Demetriadou (1), Anastasia Raoukka (1), Agathi Elpidoforou  (1), Constantine Mylonas (2), Swati Parekh (2), Peter Tessarz (2), Antonis Kirmizis (1)

N-alpha-acetyltransferase 40 (NAA40) is distinct among other histone acetyltransferases (HATs) because it deposits an acetyl moiety on the alpha-amino group at the very N-terminal tip of histones H4 and H2A, instead on the lysine side chain. The biological function of this evolutionarily conserved enzyme remained unexplored for several decades because it was thought to mediate an inert modification. However, we previously showed that NAA40-mediated N-terminal acetylation of histone H4 (N-acH4) crosstalks with an adjacent arginine methylation mark to regulate yeast cellular aging in response to caloric restriction through transcriptional control of several metabolic genes. Therefore, we are currently interested in deciphering the function of human NAA40 in carcinogenesis. We recently showed that NAA40 is frequently upregulated in primary human colorectal cancer (CRC) samples. Remarkably, depletion of NAA40 and its accompanied reduction in N-acH4 blocked colon cancer cell proliferation and reduced cell survival in vitro and in xenograft models. We also found that loss of NAA40 expression or of its HAT activity markedly induce global histone methylation. Additionally, whole transcriptome analysis showed that NAA40 knockdown leads to upregulation of key enzymes involved in one-carbon metabolism. Intriguingly, silencing of methylenetetrahydrofolate reductase (MTHFR), which links the folate to methionine cycle, rescues the induction of global histone methylation and loss of cell viability triggered by NAA40 depletion. Hence, this recent work implies that NAA40 may transcriptionally regulate vital metabolic enzymes to control the flux of carbon units into the methionine cycle influencing S-adenosylmethionine (SAM) levels and triggering epigenome reprogramming of cancer cells. Overall, our findings thus far propose that NAA40 and its associated N-acH4 are crucial epigenetic modulators in tumourigenesis and implicate these factors in rewiring cancer cell metabolism.

Poster currently not available.

(1) University of Cyprus, Cyprus
(2) Max Planck Institute for Biology of Ageing, Germany

Role of MOF acetyl transferase in mitochondrial homeostasis

PHOTO: Sukanya Guhathakurta

Authors: Sukanya Guhathakurta (1), Christoph Martensson (2), Alexander Schendzielorz (3), Bettina Warsheid (3), Thomas Becker (2), Asifa Akhtar (1)

Mitochondria lies at the centre of cellular and organismal energy homeostasis, housing a large repertoire of enzymes that are required for the synergy of various metabolic pathways. Mitochondrial gene expression and protein acetylation are two important fundamental processes situated at the crossroad between mitochondrial function and metabolic status of a cell. Gene transcription in the mitochondria has been studied over several decades, but enzymatic acetylation of mitochondria proteins has stayed so far enigmatic. MOF acetyl transferase and its KANSL complex members dually localize to the nucleus and the mitochondria in mouse and human cells. The MOF-KANSL complex regulates metabolic gene transcription in the nucleus and expression of Electron Transport Chain (mtETC) components from the mtDNA, in a cell type dependent fashion. Regulation of nuclear gene transcription by MOF is well understood, however, its control of mitochondrial function remains elusive. Here, we report that loss of MOF leads to severe mitochondrial dysfunction in Mouse Embryonic Fibroblasts (MEFs), sprouting from a stalled oxidative phosphorylation. We address the mechanisms by which the enzyme maintains mitochondrial function in these cells by using a multi-omics approach. We discovered that the role of MOF-KANSL complex in the mitochondria of aerobically respiring cells could be decoupled from its regulation of steady state RNA levels, and could further be attributed to the acetylation of mitochondrial proteins. We characterize the role of acetylation on these proteins through generation of acetylated and non-acetylated mimics. Collectively our data, along with previously published works, suggests that MOF has emerged as a moderator to strike a harmony in the context of communication between the nucleus and the mitochondria. Recent progress on the project will be discussed.

(1) Max Planck Institute for Immunobiology and Epigenetics, Germany
(2) Institute of Biochemistry and Molecular Biology, Germany
(3) Institute for Biology II, Germany

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Working on your own conference poster? Then check out 10 tips to create a scientific poster people want to stop by .

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Using chemical biology to expand the druggable proteome

Gerard Drewes
Head of Science, GSK Cellzome, Germany

In 2020 the EMBL Resource Development team and  industry partners of the EMBL Corporate Partnership Programme will bring together academic and industrial scientists with interests in chemical biology, chemogenomic libraries, pharmacology, medicinal chemistry and bioinformatics for the EMBL Conference: Expanding the Druggable Proteome with Chemical Biology (5-7 February 2020).

We spoke to co-organiser Gerard Drewes from GSK Cellzome about how chemical biology is helping to expand the druggable proteome.

How would you define the “druggable proteome”?

This is the fraction of our >20,000 human proteins that can be functionally modulated by a drug. Drugs can be small molecules or large molecules such as therapeutic antibodies. Estimates of how many proteins are “tractable” vary widely, I think there may be around 5,000. Only a subset of these 5,000 would be “druggable” which means that modulating them with a drug will also have a therapeutic benefit.

How are advances in chemical biology helping to expand the druggable proteome?

Small molecules are still the main modality for intracellular targets. Deep pockets, typical for enzymes, are more easily tractable than shallow pockets typical for protein-protein interactions. Chemical biology has developed tools to explore different types of pockets. I am excited in particular by the potential of DNA-encoded libraries, and small fragment approaches with covalent modes of action. Some of these compounds will just be “binders” but these can be made into target degraders as PROTACs.

How can these advances help our understanding of disease biology?

If we had more chemical probes, we could use these in a standardised, controlled way to interrogate target function in cell-based models, organoids, and in some cases animal models. Yes, we have gene editing now, but that is not the same as pharmacological modulation.

We also need in vitro models that translate better to in vivo. Our old immortalised cell lines won’t do, we are going to need more work in primary cells, organoids, etc.

What are the main challenges facing scientists in this field?

Lack of standardised probe sets. Bad probe compounds, e.g. with bad selectivity, are still used and wrong conclusions drawn.

Lack of translational in vitro models.

Why is it important to bring industry and academia together to discuss this topic?

Academia brings creativity, agility, fast progress of new ideas and concepts, thinking out of the box.

Industry sometimes lacks these but knows how to develop a compound into a drug, which requires a host of technologies not readily available to academia. Also, industry requires a new generation of drug targets with better validation, and historically targets are often discovered in academia. Once a target hypothesis exists, academics and industry should ideally collaborate to figure out how to drug it.

What will be the main highlight of this conference?

I see many but still hope to be surprised!

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