MTCH2-mediated mitochondrial fusion drives exit from na\xefve pluripotency in embryonic stem cells

Amir Bahat,Yehudit Zaltsman,Alon Silberman,Vladislav Krupalnik,Ayelet Erez,Andres Goldman,Michael Mullokandov,Coral Halperin,Dilshad H Khan,Emmanuel Amzallag,Atan Gross,Aaron D Schimmer,Jacob H Hanna

doi:10.1038/s41467-018-07519-w

Abstract

The role of mitochondria dynamics and its molecular regulators remains largely unknown during naïve-to-primed pluripotent cell interconversion. Here we report that mitochondrial MTCH2 is a regulator of mitochondrial fusion, essential for the naïve-to-primed interconversion of murine embryonic stem cells (ESCs). During this interconversion, wild-type ESCs elongate their mitochondria and slightly alter their glutamine utilization. In contrast, MTCH2−/− ESCs fail to elongate their mitochondria and to alter their metabolism, maintaining high levels of histone acetylation and expression of naïve pluripotency markers. Importantly, enforced mitochondria elongation by the pro-fusion protein Mitofusin (MFN) 2 or by a dominant negative form of the pro-fission protein dynamin-related protein (DRP) 1 is sufficient to drive the exit from naïve pluripotency of both MTCH2−/− and wild-type ESCs. Taken together, our data indicate that mitochondria elongation, governed by MTCH2, plays a critical role and constitutes an early driving force in the naïve-to-primed pluripotency interconversion of murine ESCs.

Highlights

The role of mitochondria dynamics and its molecular regulators remains largely unknown during naïve-to-primed pluripotent cell interconversion
These studies demonstrated that knocking out Mitochondrial carrier homolog 2 (MTCH2) in mouse embryonic fibroblasts (MEFs) using Cre recombinase in vitro results in a lesselongated/round mitochondria morphology (Fig. 1a, top left and right panels, respectively), which was quantified by morphological classification, aspect ratio calculation, and sphericity (three-dimensional (3D) structural analysis of mitochondria using computerized segmentation; Fig. 1b)
Loss of MFN2, which results in complete fragmentation of mitochondria[18], was largely rescued by the expression of MTCH2-GFP (Fig. 1f), a finding that is consistent with the idea that MTCH2 is an important regulator of mitochondria fusion

Summary

Introduction

The role of mitochondria dynamics and its molecular regulators remains largely unknown during naïve-to-primed pluripotent cell interconversion. We report that mitochondrial MTCH2 is a regulator of mitochondrial fusion, essential for the naïve-to-primed interconversion of murine embryonic stem cells (ESCs) During this interconversion, wild-type ESCs elongate their mitochondria and slightly alter their glutamine utilization. In vitro naïve pluripotency refers to embryonic stem cells (ESCs) derived from the inner cell mass of pre-implantation mouse blastocysts at E3.5, whereas in vitro primed pluripotency is represented by epiblast stem cells (EpiSCs) commonly derived from the late epiblast layer of post-implantation mouse embryos at E5.5–E6.5. These two cell types differ in their morphology, cytokine dependence, gene expression and epigenetic and metabolic profiles[2,3]. We show that mitochondria elongation, governed by MTCH2, plays a critical role and constitutes an early driving force in the naïve-to-primed pluripotency interconversion of murine ESCs

Methods

Results

Conclusion