bims-mireme 2021-09-19 papers

Issue of 2021‒09‒19
three papers selected by
Brian Spurlock
The University of North Carolina at Chapel Hill

Genes Dis. 2021 Nov;8(6): 891-906

PGC-1α promotes mitochondrial respiration and biogenesis during the differentiation of hiPSCs into cardiomyocytes.

Qin Zhou, Hao Xu, Liang Yan, Liang Ye, Xinyuan Zhang, Bin Tan, Qin Yi, Jie Tian, Jing Zhu.

Although it is widely accepted that human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are readily available, robustly reproducible, and physiologically appropriate human cells for clinical applications and research in the cardiovascular field, hiPSC-CMs cultured in vitro retain an immature metabolic phenotype that limits their application, and little is known about the underlying molecular mechanism controlling mitochondrial metabolic maturation during human induced pluripotent stem cells (hiPSCs ) differentiation into cardiomyocytes. In this study, we found that peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) played an important role in inducing mitochondrial biogenesis and establishing oxidative phosphorylation (OXPHOS) during the cardiac differentiation of hiPSCs. Knocking down PGC-1α by siRNA impaired mitochondrial respiration, while upregulating PGC-1α by ZLN005 promoted mitochondrial biosynthesis and function by regulating the expression of downstream genes involved in mitochondrial dynamics and oxidative metabolism in hiPSC-CMs. Furthermore, we found that estrogen-related receptor α (ERRα) was required for the induction of PGC-1α stimulatory effects in hiPSC-CMs. These findings provide key insights into the molecular control of mitochondrial metabolism during cardiac differentiation and may be used to generate more metabolically mature cardiomyocytes for application.

Keywords: Cardiac differentiation; Maturation; Mitochondrial metabolism; PGC-1α; hiPSCs

DOI: https://doi.org/10.1016/j.gendis.2020.12.006

Placenta. 2021 Sep 06. pii: S0143-4004(21)00582-8. [Epub ahead of print]114 100-107

Hypoxic effects on the mitochondrial content and functions of the placenta in fetal growth restriction.

Yue-Ying Xu, Yuan Liu, Ling Cui, Wei-Bin Wu, Martin John Quinn, Ramkumar Menon, Hui-Juan Zhang.

INTRODUCTION: In this study we examined the hypothesis that a hypoxic intrauterine environment causes mitochondrial dysfunction of trophoblasts in fetal growth restriction (FGR).METHODS: The mtDNA content, mRNA levels of mitochondrial encoded genes (ND6, COX I), mitochondrial membrane proteins (COX I, COX IV and VDAC), HIF-1α and BINP3 (mitophagy receptor) protein levels were examined in FGR placentas and normal placentas. The mitochondrial function (ATP production and mitochondrial membrane potential-ΔΨm) and above related proteins were further examined in hypoxic HTR-8/SVneo cells induced by cobalt chloride (CoCl2). Mitophagy and its regulating mechanism under hypoxia in FGR was also investigated.
RESULTS: Compared with normal controls, both FGR placentas and CoCl2-treated trophoblast cells demonstrated statistically lower mtDNA content, reduced mRNAs of mitochondrial encoding genes, and decreased mitochondrial membrane proteins, accompanied by increased HIF-1α. Mitochondrial functions were impaired as demonstrated by decreased ATP production, and, reduced ΔΨm in CoCl2-treated cells. Meanwhile, mitophagy was markedly enhanced as indicated by increased LC3 fluorescent puncta in mitochondria of hypoxic trophoblastic cells. The upregulated BINP3 expression was demonstrated in FGR placentas as well as in hypoxic trophoblastic cells.
DISCUSSION: We demonstrated that hypoxic conditions lead to impaired mitochondrial function in trophoblasts in FGR. Reduced mtDNA may be associated with enhanced mitophagy via activating HIF-1α/BINP3 signalling pathway, that may, in turn, affect nutrition and energy transfer to the growth-restricted fetus.

Keywords: FGR; Hypoxia; Mitochondria; Mitophagy; Placental dysfunction

DOI: https://doi.org/10.1016/j.placenta.2021.09.003

Malays J Med Sci. 2021 Aug;28(4): 5-13

A Review of the Impact of Calorie Restriction on Stem Cell Potency.

Marcello Mikhael Kadharusman, Radiana Dhewayani Antarianto, Novi Silvia Hardiany.

Calorie restriction (CR) prolongs lifespan in various species and also minimises pathologies caused by aging. One of the characteristics seen in age-related pathologies is stem cell exhaustion. Here, we review the various impacts of CR on mammalian health mediated through stem cell potency in various tissues. This study comprised of a literature search through NCBI, Science Direct, Google Scholar and PubMed, focusing on the impact of CR on pluripotency. In the skeletal muscle, CR acts as an anti-inflammatory agent and increases the presence of satellite cells endogenously to improve regeneration, thus causing a metabolic shift to oxidation to meet oxygen demand. In the intestinal epithelium, CR suppresses the mechanistic target of rapamycin complex 1 (mTORC1) signalling in Paneth cells to shift the stem cell equilibrium towards self-renewal at the cost of differentiation. In haematopoiesis, CR prevents deterioration or maintains the function of haematopoietic stem cells (HSCs) depending on the genetic variation of the mice. In skin and hair follicles, CR increases the thickness of the epidermis and hair growth and improves hair retention through stem cells. CR mediates the proliferation and self-renewal of stem cells in various tissues, thus increasing its regenerative ability.

Keywords: calorie restriction; pluripotency; stem cell

DOI: https://doi.org/10.21315/mjms2021.28.4.2