MDH1-mediated malate-aspartate NADH shuttle maintains the activity levels of fetal liver hematopoietic stem cells

Abstract

The connections between energy metabolism and stemness of hematopoietic stem cells (HSCs) at different developmental stages remain largely unknown. We herein generate a transgenic mouse line for the genetically encoded NADH/NAD+ sensor (SoNar) and demonstrate that there exist three distinct fetal liver hematopoietic cell populations according to the ratios of SoNar fluorescence. SoNar-low cells have an enhanced level of mitochondrial respiration, but similar glycolytic level to SoNar-high cells. Interestingly, 10% of SoNar-low cells are enriched for 65% of total immunophenotypical fetal liver HSCs (FL-HSCs) and contain approximately 5-fold greater functional HSCs than that of SoNar-high counterparts. SoNar can monitor sensitively the dynamic changes of energy metabolism in HSCs both in vitro and in vivo. Mechanistically, STAT3 transactivates MDH1 to sustain the malate-aspartate NADH shuttle activity and the HSC self-renewal and differentiation. We reveal an unexpected metabolic program of FL-HSCs and provide a powerful genetic tool for metabolic studies of HSCs or other types of stem cells.

Genetically encoded biosensors for evaluating NAD+/NADH ratio in cytosolic and mitochondrial compartments

“…Recently, the circularly permuted yellow fluorescent protein (cpYFP) was inserted into the surface loops of T-Rex protein ( Thermus aquaticus ) to form a fluorescent biosensor, named SoNar, which has two excitation peaks (410 and 480 nm) and one emission peak (520 nm) ( Zhao et al, 2015 ). Non-targeted SoNar has been characterized and used to monitor the cytosolic NAD + /NADH ratio in live cells and in a real-time manner ( Chen et al, 2021 ; Gu et al, 2020 ; Hao et al, 2019 ; Oldham et al, 2015 ; Titov et al, 2016 ; Zhao et al, 2016 ). We modified SoNar and targeted it into the mitochondrial matrix.…”

Gadus morhua Eggs Sialoglycoprotein Prevent Estrogen Deficiency-Induced High Bone Turnover by Controlling OPG/RANKL/TRAF6 Pathway and Serum Metabolism

“…However, there was no statistically significant change in the positive ion model ( Figure 4C ). The histidine and L -aspartate, which decreased after E2 group, are associated with osteoarthritis ( 39 ) and liver function ( 40 ), which indicates that the E2 protected bone mass via histidine and L -aspartate metabolism.…”

Warburg-like Metabolic Reprogramming in Aging Intestinal Stem Cells Contributes to Tissue Hyperplasia

“…Following sequential 405/488-nm excitation of SoNaR, comparative emission at 520 nm reveals a cell’s relative NADH/NAD+ ratio. When expressed in progenitor cells and using live imaging, SoNaR was acutely sensitive to genetic perturbations predicted to decrease NADH oxidation: disrupting the ETC or knocking down malate dehydrogenase, an essential component of the malate:aspartate shuttle ( Gu et al, 2020 ; Lee et al, 2012 ), raised NADH/NAD+ ratios ( Figures S3E and S3F ). Crucially, cpYFP, the conventional fluorescent protein from which the modified SoNaR is derived, did not respond to perturbations altering SoNaR fluorescence ( Figures S3G and S3H ).…”