Prohibitin 2 Regulates the Proliferation and Lineage-Specific Differentiation of Mouse Embryonic Stem Cells in Mitochondria

Abstract

BackgroundThe pluripotent state of embryonic stem (ES) cells is controlled by a network of specific transcription factors. Recent studies also suggested the significant contribution of mitochondria on the regulation of pluripotent stem cells. However, the molecules involved in these regulations are still unknown.Methodology/Principal FindingsIn this study, we found that prohibitin 2 (PHB2), a pleiotrophic factor mainly localized in mitochondria, is a crucial regulatory factor for the homeostasis and differentiation of ES cells. PHB2 was highly expressed in undifferentiated mouse ES cells, and the expression was decreased during the differentiation of ES cells. Knockdown of PHB2 induced significant apoptosis in pluripotent ES cells, whereas enhanced expression of PHB2 contributed to the proliferation of ES cells. However, enhanced expression of PHB2 strongly inhibited ES cell differentiation into neuronal and endodermal cells. Interestingly, only PHB2 with intact mitochondrial targeting signal showed these specific effects on ES cells. Moreover, overexpression of PHB2 enhanced the processing of a dynamin-like GTPase (OPA1) that regulates mitochondrial fusion and cristae remodeling, which could induce partial dysfunction of mitochondria.Conclusions/SignificanceOur results suggest that PHB2 is a crucial mitochondrial regulator for homeostasis and lineage-specific differentiation of ES cells.

Prohibitin 2: At a communications crossroads

“…Interestingly, in this study, while exogenous expression of a S176A mutant had little effect on cell viability, exogenous expression of a S91A phospho‐mutant resulted in a rapid and complete apoptosis of NB4 cells within 24 h after transfection . Such apoptosis is a hallmark of mitochondria catastrophe and this phenotype matched those observed in embryonic stem cells in which the PHBs were knocked‐out and cell lines where PHBs were knocked‐down using siRNA (Fig. ).…”

Connecting Mitochondria, Metabolism, and Stem Cell Fate

“…Overexpression of PHB2, which is normally high in mESCs, favors the proliferation of mESCs, but inhibits their differentiation into neuronal and endodermal lineages. The overexpression of PHB2 also prevents the maturation of mitochondria observed during mESC differentiation [62]. The effect of PHB2 on the maturation of mitochondria is mediated by enhanced OPA1 processing, resulting in increased mitochondrial fission and dysfunctional mitochondria [62].…”

“…The overexpression of PHB2 also prevents the maturation of mitochondria observed during mESC differentiation [62]. The effect of PHB2 on the maturation of mitochondria is mediated by enhanced OPA1 processing, resulting in increased mitochondrial fission and dysfunctional mitochondria [62]. The depletion of protein tyrosine phosphatase, mitochondrial 1 (PTPMT1), a mitochondrial phosphatidylinositol phosphate (PIP) phosphatase, reduces oxidative metabolism, increases glycolysis in mESCs, and prevents their differentiation.…”

Prohibitin-mediated mitochondrial ubiquitination during spermiogenesis in Chinese mitten crab Eriocheir sinensis

“…PHB complexes are produced through interactions in the N-terminal hydrophobic region on the mitochondrial inner membrane [16, 17]. In mitochondria, PHB was also associated with mitophagy, stabilizing mitochondria genome through TFAM (Transcription Factor A, Mitochondrial), ROS (Reactive Oxygen Free Radical) reduction, mitochondrial morphology and mitochondrial apoptosis [18–22]. The function of PHB during spermatogenesis has been reported in many species, including Rattus norvegicus [23], Saccharomyces cerevisiae [24], Caenorhabditis elegans [25], Procambarus clarkii [26], Cynops orientalis [27], and Boleophthalmus pectinirostris [28].…”