scholarly journals Chloroplasts Require Glutathione Reductase to Balance Reactive Oxygen Species and Maintain Efficient Photosynthesis

2019 ◽  
Author(s):  
Stefanie J. Müller-Schüssele ◽  
Ren Wang ◽  
Desirée D. Gütle ◽  
Jill Romer ◽  
Marta Rodriguez-Franco ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Plant Growth ◽  
Glutathione Reductase ◽  
Critical Role ◽  
Reactive Oxygen ◽  
List Type ◽  
Oxygen Species ◽  
Protein Repair ◽  
Glutathione Redox

SummaryThiol-based redox-regulation is vital to coordinate chloroplast functions depending on illumination. Yet, how the redox-cascades of the thioredoxin and glutathione redox machineries integrate metabolic regulation and reactive oxygen species (ROS) detoxification remains largely unresolved. We investigate if maintaining a highly reducing stromal glutathione redox potential (EGSH) via glutathione reductase (GR) is necessary for functional photosynthesis and plant growth.Since absence of the plastid/mitochondrial GR is embryo-lethal in Arabidopsis thaliana, we used the model moss Physcomitrella patens to create knock-out lines. We dissect the role of GR in chloroplasts by in vivo monitoring stromal EGSH dynamics, and reveal changes in protein abundances by metabolic labelling.Whereas stromal EGSH is highly reducing in wildtype and clearly responsive to light, the absence of GR leads to a partial oxidation, which is not rescued by light. Photosynthetic performance and plant growth are decreased with increasing light intensities, while ascorbate and zeaxanthin levels are elevated. An adjustment of chloroplast proteostasis is pinpointed by the induction of plastid protein repair and degradation machineries.Our results indicate that the plastid thioredoxin and glutathione redox systems operate largely independently. They reveal a critical role of GR in maintaining efficient photosynthesis.

scholarly journals Critical Role of Lama4 for Hematopoiesis Regeneration and Acute Myeloid Leukemia Progression

Blood ◽  
2021 ◽  
Author(s):  
Huan Cai ◽  
Makoto Kondo ◽  
Lakshmi Sandhow ◽  
Pingnan Xiao ◽  
Anne-Sofie Johansson ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Proliferation ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Critical Role ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Bm Niche ◽  
Acute Myeloid

Impairement of normal hmatopoiesis and leukemia progression are two well-linked processes during leukemia development and controlled by the bone marrow (BM) niche. Extracellular matrix proteins including laminin are important BM niche components. However, their role in hematopoiesis regeneration and leukemia is unknown. Laminin α4 (Lama4), a major receptor-binding chain of several laminins, is altered in BM niches in mice with acute myeloid leukemia (AML). So far, the impact of Lama4 on leukemia progression remains unknown. We here report that Lama4 deletion in mice resulted in impaired hematopoiesis regeneration following irradiation-induced stress, which is accompanied with altered BM niche composition and inflammation. Importantly, in a transplantation-induced MLL-AF9 AML mouse model, we demonstrate accelerated AML progression and relapse in Lama4-/-mice. Upon AML exposure, Lama4-/- mesenchymal stem cells (MSCs) exhibited dramatic molecular alterations including upregulation of inflammatory cytokines that favor AML growth. Lama4-/- MSCs displayed increased anti-oxidant activities and promoted AML stem cell proliferation and chemoresistance to cytarabine, which was accompanied by increased mitochondrial transfer from the MSCs to AML cells and reduced reactive oxygen species in AML cells in vitro. Similarly, we detected lower levels of reactive oxygen species in AML cells from Lama4-/- mice post-cytarabine treatment. Notably, LAMA4 inhibition or knockdown in human MSCs promoted human AML cell proliferation and chemoprotection. Together, our study for the first time demonstrates a critical role of Lama4 in impeding AML progression and chemoresistance. Targeting Lama4 signaling pathways may offer potential new therapeutic options for AML.

scholarly journals Yap1-Regulated Glutathione Redox System Curtails Accumulation of Formaldehyde and Reactive Oxygen Species in Methanol Metabolism of Pichia pastoris

2009 ◽  
Vol 8 (4) ◽  
pp. 540-549 ◽  
Author(s):  
Taisuke Yano ◽  
Emiko Takigami ◽  
Hiroya Yurimoto ◽  
Yasuyoshi Sakai
Keyword(s):  
Reactive Oxygen Species ◽  
Pichia Pastoris ◽  
Critical Role ◽  
Reactive Oxygen ◽  
Redox System ◽  
Reduced Form ◽  
Growth Defect ◽  
Oxygen Species ◽  
Glutathione Redox System ◽  
Glutathione Redox

ABSTRACT The glutathione redox system, including the glutathione biosynthesis and glutathione regeneration reaction, has been found to play a critical role in the yeast Pichia pastoris during growth on methanol, and this regulation was at least partly executed by the transcription factor PpYap1. During adaptation to methanol medium, PpYap1 transiently localized to the nucleus and activated the expression of the glutathione redox system and upregulated glutathione reductase 1 (Glr1). Glr1 activates the regeneration of the reduced form of glutathione (GSH). Depletion of Glr1 caused a severe growth defect on methanol and hypersensitivity to formaldehyde (HCHO), which could be complemented by addition of GSH to the medium. Disruption of the genes for the HCHO-oxidizing enzymes PpFld1 and PpFgh1 caused a comparable phenotype, but disruption of the downstream gene PpFDH1 did not, demonstrating the importance of maintaining intracellular GSH levels. Absence of the peroxisomal glutathione peroxidase Pmp20 also triggered nuclear localization of PpYap1, and although cells were not sensitive to HCHO, growth on methanol was again severely impaired due to oxidative stress. Thus, the PpYap1-regulated glutathione redox system has two important roles, i.e., HCHO metabolism and detoxification of reactive oxygen species.

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