MGST1, a GSH transferase/peroxidase essential for development and hematopoietic stem cell differentiation

Abstract

We show for the first time that, in contrast to other glutathione transferases and peroxidases, deletion of microsomal glutathione transferase 1 (MGST1) in mice is embryonic lethal. To elucidate why, we used zebrafish development as a model system and found that knockdown of MGST1 produced impaired hematopoiesis. We show that MGST1 is expressed early during zebrafish development and plays an important role in hematopoiesis. High expression of MGST1 was detected in regions of active hematopoiesis and co-expressed with markers for hematopoietic stem cells. Further, morpholino-mediated knock-down of MGST1 led to a significant reduction of differentiated hematopoietic cells both from the myeloid and the lymphoid lineages. In fact, hemoglobin was virtually absent in the knock-down fish as revealed by diaminofluorene staining. The impact of MGST1 on hematopoiesis was also shown in hematopoietic stem/progenitor cells (HSPC) isolated from mice, where it was expressed at high levels. Upon promoting HSPC differentiation, lentiviral shRNA MGST1 knockdown significantly reduced differentiated, dedicated cells of the hematopoietic system. Further, MGST1 knockdown resulted in a significant lowering of mitochondrial metabolism and an induction of glycolytic enzymes, energetic states closely coupled to HSPC dynamics. Thus, the non-selenium, glutathione dependent redox regulatory enzyme MGST1 is crucial for embryonic development and for hematopoiesis in vertebrates.

Integrative proteomics and phosphoproteomics in pulmonary arterial hypertension

“…Within the CellROX hi subset, the ROS level generated by PAH PAEC exposed to menadione was significantly higher than in control cells (CellROX Median Fluorescence Intensity menadione/baseline, Controls 0.90 ± 0.05; PAH 1.06 ± 0.06, P = 0.04; one-tailed t -test), indicating greater capacity for ROS generation in PAH PAEC under conditions of redox stress. In addition, mitochondrial protein MGST1, which protects against oxidative stress and regulates mitochondrial metabolism 43 , was downregulated in PAH ( P = 0.01) (Supplementary Tables S14 and S17). Glutathione peroxidases (GPX) are additional antioxidants that play a major role in the protection against oxidative stress by detoxification of hydrogen peroxide.…”

The NOTCH1-dependent HIF1α/VGLL4/IRF2BP2 oxygen sensing pathway triggers erythropoiesis terminal differentiation

“…While MOs mimic gene knock-down, mRNA microinjection simulates gene expression. The MOs were designed using Genetools (www.gene-tools.com) [30] and the sequences are as follows: Zebrafish irf2bp2a MO: 5′-ACGACATCGCTCTCTCTCGGGCGAA-3’; zebrafish tead1a MO: 5′-CATGGCAATGGATGTGATCTCAGA-3’; zebrafish hif1 MO: 5′-GGTAACAGTAGTACTCATG-3’. Full-length mRNA samples were all synthesized using an SP6 kit (Life Technologies) from plasmid products after endonuclease digestion.…”

Racial disparities, cancer and response to oxidative stress

“…The role of pheomelanin vs eumelanin in immune function are also poorly understood. Glutathione S-transferases and glutathione (GSH; discussed below) are critical contributors to melanin synthesis and these same proteins are involved in hematopoiesis and immunity (Brautigam et al, 2018;. Formation of intermediates within the melanin synthesis pathway such as dopaquinone likely involve GST and human polymorphisms have varying efficacy in catalyzing this reaction.…”

“…However, there is information to suggest that ethnicity may be linked with differences in expression of phase I and II detoxification enzymes. Perhaps the most obvious is the fact that melanin (and more precisely pheomelanin) biosynthesis can be linked with glutathione conjugation of dopaquinone and this is likely regulated by GST's (Agrup et al, 1975;Brautigam et al, 2018;Dagnino-Subiabre et al, 2000).…”