Publications by authors named "Marine Barthez"

3 Publications

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Stem Cell Metabolism and Diet.

Curr Stem Cell Rep 2020 Dec 28;6(4):119-125. Epub 2020 Oct 28.

Program in Metabolic Biology, Nutritional Sciences & Toxicology, University of California, Berkeley, CA 94720, 119 Morgan Hall, University of California, Berkeley, CA 94720.

Purpose Of Review: Diet has profound impacts on health and longevity. Evidence is emerging to suggest that diet impinges upon the metabolic pathways in tissue-specific stem cells to influence health and disease. Here, we review the similarities and differences in the metabolism of stem cells from several tissues, and highlight the mitochondrial metabolic checkpoint in stem cell maintenance and aging. We discuss how diet engages the nutrient sensing metabolic pathways and impacts stem cell maintenance. Finally, we explore the therapeutic implications of dietary and metabolic regulation of stem cells.

Recent Findings: Stem Cell transition from quiescence to proliferation is associated with a metabolic switch from glycolysis to mitochondrial OXPHOS and the mitochondrial metabolic checkpoint is critically controlled by the nutrient sensors SIRT2, SIRT3, and SIRT7 in hematopoietic stem cells. Intestine stem cell homeostasis during aging and in response to diet is critically dependent on fatty acid metabolism and ketone bodies and is influenced by the niche mediated by the nutrient sensor mTOR.

Summary: Nutrient sensing metabolic pathways critically regulate stem cell maintenance during aging and in response to diet. Elucidating the molecular mechanisms underlying dietary and metabolic regulation of stem cells provides novel insights for stem cell biology and may be targeted therapeutically to reverse stem cell aging and tissue degeneration.
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http://dx.doi.org/10.1007/s40778-020-00180-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7992378PMC
December 2020

Human ZKSCAN3 and Drosophila M1BP are functionally homologous transcription factors in autophagy regulation.

Sci Rep 2020 06 15;10(1):9653. Epub 2020 Jun 15.

Aix Marseille Université, CNRS, IBDM, UMR 7288, Marseille, 13288, Cedex 09, France.

Autophagy is an essential cellular process that maintains homeostasis by recycling damaged organelles and nutrients during development and cellular stress. ZKSCAN3 is the sole identified master transcriptional repressor of autophagy in human cell lines. How ZKSCAN3 achieves autophagy repression at the mechanistic or organismal level however still remains to be elucidated. Furthermore, Zkscan3 knockout mice display no discernable autophagy-related phenotypes, suggesting that there may be substantial differences in the regulation of autophagy between normal tissues and tumor cell lines. Here, we demonstrate that vertebrate ZKSCAN3 and Drosophila M1BP are functionally homologous transcription factors in autophagy repression. Expression of ZKSCAN3 in Drosophila prevents premature autophagy onset due to loss of M1BP function and conversely, M1BP expression in human cells can prevent starvation-induced autophagy due to loss of nuclear ZKSCAN3 function. In Drosophila ZKSCAN3 binds genome-wide to sequences targeted by M1BP and transcriptionally regulates the majority of M1BP-controlled genes, demonstrating the evolutionary conservation of the transcriptional repression of autophagy. This study thus  allows the potential for transitioning the mechanisms, gene targets and plethora metabolic processes controlled by M1BP onto ZKSCAN3 and opens up Drosophila as a tool in studying the function of ZKSCAN3 in autophagy and tumourigenesis.
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http://dx.doi.org/10.1038/s41598-020-66377-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7296029PMC
June 2020

The Hox proteins Ubx and AbdA collaborate with the transcription pausing factor M1BP to regulate gene transcription.

EMBO J 2017 10 4;36(19):2887-2906. Epub 2017 Sep 4.

Aix Marseille Université, CNRS, IBDM, UMR 7288, Marseille, France

In metazoans, the pausing of RNA polymerase II at the promoter (paused Pol II) has emerged as a widespread and conserved mechanism in the regulation of gene transcription. While critical in recruiting Pol II to the promoter, the role transcription factors play in transitioning paused Pol II into productive Pol II is, however, little known. By studying how Hox transcription factors control transcription, we uncovered a molecular mechanism that increases productive transcription. We found that the Hox proteins AbdA and Ubx target gene promoters previously bound by the transcription pausing factor M1BP, containing paused Pol II and enriched with promoter-proximal Polycomb Group (PcG) proteins, yet lacking the classical H3K27me3 PcG signature. We found that AbdA binding to M1BP-regulated genes results in reduction in PcG binding, the release of paused Pol II, increases in promoter H3K4me3 histone marks and increased gene transcription. Linking transcription factors, PcG proteins and paused Pol II states, these data identify a two-step mechanism of Hox-driven transcription, with M1BP binding leading to Pol II recruitment followed by AbdA targeting, which results in a change in the chromatin landscape and enhanced transcription.
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http://dx.doi.org/10.15252/embj.201695751DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5623858PMC
October 2017
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