Metabolite patterns in human myeloid hematopoiesis result from lineage-dependent active metabolic pathways

Abstract

<jats:title>Abstract</jats:title><jats:p>Assessment of hematotoxicity from environmental or xenobiotic compounds is of notable interest and is frequently assessed via the colony forming unit (CFU) assay. Identification of the mode of action of single compounds is of further interest, as such often enables transfer of results across different tissues and compounds. Metabolomics displays one promising approach for identifying such, nevertheless, suitability with current protocols is restricted. Here, we combined an HSPC expansion approach with distinct lineage differentiations, resulting in formation of erythrocytes, dendritic cells and neutrophils. We examined the unique combination of fluxes in glycolysis, glutaminolysis, polyamine synthesis, fatty acid oxidation and synthesis, as well as glycerophospholipid and sphingolipid metabolism. We further assessed their interconnections and essentialness for each lineage formation. By this, we provide further insights into metabolic fluxes during differentiation of HSPC into different lineages, enabling profound understanding of possible metabolic changes in each lineage caused by exogenous compounds.</jats:p>

Active fatty acid oxidation defines the cellular response towards reactive oxygen species

“…As we previously identified high fatty acid (FA) synthesis in combination with low FA oxidation (FAO) as underlying mechanism for increased glycerophospholipid and SL levels in erythrocytes, it is reasonable to assume initial stimulation of FA and GPL synthesis by DEHP. (Kaiser et al, 2020) This is further supported by the sum of measured ester GPL and ether GPL, which were raised at day 2 by DEHP (Fig. 2 d,e).…”

“…As the metabolism plays a central role during hematopoietic lineage commitment and the cellular response towards exogenous stimuli, we performed quantitation of 200 metabolites over the differentiation period, including amino acids and biogenic amines, acylcarnitines, glycerophospho-(GPL) and sphingolipids and the sum of hexoses. (Kaiser et al, 2020; Oburoglu et al, 2016, 2014)…”

“…The total acyl-CoA pool controlling the rate of GPL, EL and SL synthesis, however, is fuelled by cholesterol ester (CE) and triglyceride (TG) degradation in dendritic cells, while de novo lipid synthesis replenishes acyl-CoA levels in erythrocytes. (Kaiser et al, 2020) These different sources for lipid anabolism, in turn, may be responsible for the differential effects of DEHP on the lipidome of both lineages. DEHP, therefore, lowers total lipid levels, glycolysis, glutaminolysis as well as polyamine synthesis in dendritic cells.…”

“…As major metabolic alterations by DEHP were observed in the lipidome of both other lineages and neutrophils are the only lineage with active FAO, we conclude a relationship between DEHP and FAO activity. (Kaiser et al, 2020; Oburoglu et al, 2016; Riffelmacher et al, 2017)…”

“…Between these lineages, metabolic fluxes uniquely differ, while neutrophils were the only lineage with active FAO. (Kaiser et al, 2020) Here, we assessed the impact of DEHP on the different lineage differentiations and found profound inhibitory effects on erythroid and dendritic cell differentiation, whereas neutrophil differentiation was enhanced. Metabolic profiling indicated global disturbance of the lipidome, as well as reduced glutaminolysis and glycolysis in both negatively affected lineages.…”