Exercise during pregnancy mitigates the adverse effects of maternal obesity on adult male offspring vascular function and alters one-carbon metabolism

Maternal obesity during pregnancy can adversely affect adult offspring vascular endothelial function. This study examined whether maternal exercise during pregnancy and lactation mitigates the adverse effects of maternal obesity on offspring vascular endothelial function. Female (C57BL/6N) mice were fed from weaning a control diet (10% kcal fat) or western diet (45% kcal fat) to induce excess adiposity (maternal obesity). After 13 weeks, the female mice were bred and maintained on the diets, with and without access to a running wheel (exercise), throughout breeding, pregnancy, and lactation. Offspring were weaned onto the control or western diet and fed for 13 weeks; male offspring were studied. Maternal exercise prevented the adverse effects of maternal obesity on offspring vascular endothelial function. However, this was dependent on offspring diet and the positive effect of maternal exercise was only observed in offspring fed the western diet. This was accompanied by alterations in aorta and liver one-carbon metabolism, suggesting a role for these pathways in the improved endothelial function observed in the offspring. Obesity and exercise had no effect on endothelial function in the dams but did affect aorta and liver one-carbon metabolism, suggesting the phenotype observed in the offspring may be due to obesity and exercise-induced changes in one-carbon metabolism in the dams. Our findings demonstrate that maternal exercise prevented vascular dysfunction in male offspring from obese dams and is associated with alterations in one-carbon metabolism.

Deep Phenotyping by Mass Cytometry and Single-Cell RNA-Sequencing Reveals LYN-Regulated Signaling Profiles Underlying Monocyte Subset Heterogeneity and Lifespan

RATIONALE

Monocytes are key effectors of the mononuclear phagocyte system, playing critical roles in regulating tissue homeostasis and coordinating inflammatory reactions, including those involved in chronic inflammatory diseases such as atherosclerosis. Monocytes have traditionally been divided into 2 major subsets termed conventional monocytes and patrolling monocytes (pMo) but recent systems immunology approaches have identified marked heterogeneity within these cells, and much of what regulates monocyte population homeostasis remains unknown. We and others have previously identified LYN tyrosine kinase as a key negative regulator of myeloid cell biology; however, LYN's role in regulating specific monocyte subset homeostasis has not been investigated.

OBJECTIVE

We sought to comprehensively profile monocytes to elucidate the underlying heterogeneity within monocytes and dissect how Lyn deficiency affects monocyte subset composition, signaling, and gene expression. We further tested the biological significance of these findings in a model of atherosclerosis.

METHODS AND RESULTS

Mass cytometric analysis of monocyte subsets and signaling pathway activation patterns in conventional monocytes and pMos revealed distinct baseline signaling profiles and far greater heterogeneity than previously described. Lyn deficiency led to a selective expansion of pMos and alterations in specific signaling pathways within these cells, revealing a critical role for LYN in pMo physiology. LYN's role in regulating pMos was cell-intrinsic and correlated with an increased circulating half-life of Lyn-deficient pMos. Furthermore, single-cell RNA sequencing revealed marked perturbations in the gene expression profiles of Lyn^-/- monocytes with upregulation of genes involved in pMo development, survival, and function. Lyn deficiency also led to a significant increase in aorta-associated pMos and protected Ldlr^-/- mice from high-fat diet-induced atherosclerosis.

CONCLUSIONS

Together our data identify LYN as a key regulator of pMo development and a potential therapeutic target in inflammatory diseases regulated by pMos.

Maternal folic acid supplementation with vitamin B12 deficiency during pregnancy and lactation affects the metabolic health of adult female offspring but is dependent on offspring diet

Epidemiologic studies have reported relationships between maternal high folate and/or low B₁₂ status during pregnancy and greater adiposity and insulin resistance in children. The goal of this study was to determine the effects of maternal folic acid supplementation (10 mg/kg diet), with (50 μg/kg diet) and without B₁₂, on adult female offspring adiposity and glucose homeostasis. Female C57BL/6J mice were fed 1 of 3 diets from weaning and throughout breeding, pregnancy, and lactation: control (2 mg/kg diet folic acid, 50 μg/kg diet B₁₂), supplemental folic acid with no B₁₂ (SFA-B₁₂), or supplemental folic acid with adequate B₁₂ (SFA+B₁₂). Female offspring were weaned onto the control diet or a Western diet (45% energy fat, 2 mg/kg diet folic acid, 50 μg/kg diet B₁₂) for 35 wk. After weaning, control diet-fed offspring with SFA-B₁₂ dams had fasting hyperglycemia, glucose intolerance, lower β cell mass, and greater islet hepatocyte nuclear factor 1 homeobox α and nuclear receptor subfamily 1 group H member 3 mRNA than did offspring from control dams. In Western diet-fed offspring, those with SFA-B₁₂ dams had lower fasting blood glucose and plasma insulin concentrations, and were smaller than control offspring. Our findings suggest that maternal folic acid supplementation with B₁₂ deficiency during pregnancy/lactation programs the metabolic health of adult female offspring but is dependent on offspring diet.-Henderson, A. M., Tai, D. C., Aleliunas, R. E., Aljaadi, A. M., Glier, M. B., Xu, E. E., Miller, J. W., Verchere, C. B., Green, T. J., Devlin, A. M. Maternal folic acid supplementation with vitamin B₁₂ deficiency during pregnancy and lactation affects the metabolic health of adult female offspring but is dependent on offspring diet.

Macrophage heterogeneity and cholesterol homeostasis: classically-activated macrophages are associated with reduced cholesterol accumulation following treatment with oxidized LDL

Macrophages are centrally involved during atherosclerosis development and are the predominant cell type that accumulates cholesterol in the plaque. Macrophages however, are heterogeneous in nature reflecting a variety of microenvironments and different phenotypes may be more prone to contribute towards atherosclerosis progression. Using primary human monocyte-derived macrophages, we sought to evaluate one aspect of atherogenic potential of different macrophage phenotypes by determining their propensity to associate with and accumulate oxidized low density lipoprotein (oxLDL). Classically-activated macrophages treated simultaneously with interferon γ (IFNγ) and tumor necrosis factor α (TNFα) associated with less oxLDL and accumulated less cholesterol compared to untreated controls. The combined treatment of IFNγ and TNFα reduced the mRNA expression of CD36 and the expression of both cell surface CD36 and macrophage scavenger receptor 1 (MSR1) protein. Under oxLDL loaded conditions, IFNγ and TNFα did not reduce macrophage protein expression of the transcription factor peroxisome proliferator-actived receptor γ (PPARγ) which is known to positively regulate CD36 expression. However, macrophages treated with IFNγ attenuated the ability of the PPARγ-specific agonist rosiglitazone from upregulating cell surface CD36 protein expression. Our results demonstrate that the observed reduction of cholesterol accumulation in macrophages treated with IFNγ and TNFα following oxLDL treatment was due at least in part to reduced cell surface CD36 and MSR1 protein expression.