| Objectives: The Developmental Origins of Health and Disease(DOHa D)theory proposes that metabolic diseases can be traced back to the fetus,with in utero exposure to maternal factors such as hyperglycemia,obesity,and infections potentially reprogramming the fetus’ s cells,resulting in long-term adverse outcomes that persist even into adulthood.Gestational Diabetes Mellitus(GDM)is the most common metabolic disease during pregnancy.Epidemiological studies have shown that GDM can increase the risk of long-term adverse events such as diabetes and atherosclerotic cardiovascular disease in offspring,but the underlying mechanism remains unclear.This study aims to clarify the characteristics of cord blood immune cells at the single-cell level,the effect of GDM on the homeostasis of fetal peripheral immune cells,and to speculate the effect of the characteristics of these immune cells on the long-term risk of metabolic diseases in offspring.The immune age prediction model was constructed to quantify the effect of GDM on the aging of monocytes in offspring.Methods: Single-cell RNA sequencing technology was used to analyze and map the immune characteristics of umbilical cord blood(UCB),and the single-cell data were compared with those of peripheral blood immune cells from children and adolescents to find out the characteristics of immune cells in UCB.Then,single-cell RNA sequencing technology was used to analyze Cord Blood Mononuclear Cells(CBMC)of pregnant women with GDM and Healthy Donors(HD)to determine the effect of GDM on cord blood immune cells.The GDM cohort was further enrolled to verify the results of single-cell sequencing.The transcriptional characteristics of the pro-inflammatory monocyte subsets that had the greatest effect on the offspring of GDM were analyzed,and compared with macrophages,which play an important role in the unstable plaque of atherosclerosis,to find out the common characteristics between them.Finally,based on the age characteristics of monocytes,the immune age prediction model of such cells was constructed by using the expression of age-related genes to explore the additional effect of GDM on the immune age process of UCB monocytes.Results:(1)Single-cell sequencing revealed the characteristics of adaptive immune cells in UCB.Compared with the immune cells in peripheral blood of children or adolescents,CCR7+T cell subsets and IL4R+B cell subsets accounted for more than 80% of adaptive immune cells in UCB.The ability of these adaptive immune cells to secrete cytokines was inhibited.However,the CD69 expression in NK cells was only one third of that in adolescents,and the CD81+expression in NK cells was 10 times higher than that in adolescents.Compared with the peripheral blood of children and adolescents,monocytes were the cell subset with the most differentially expressed genes in cord blood,and their composition and function changes were also obvious.The proportion of monocytes with high expression of IL1B(IL-1β)and CXCL8(IL-8)in UCB monocytes was less than 1/10 of that in adolescents,while the proportion of monocytes with high expression of RACK1 in UCB monocytes was nearly 10 times of that in adolescents,and the expression of inflammatory suppressor gene TGFA/B1 was relatively higher.(2)Effect of GDM on immune characteristics of CBMC in cord blood:The proportion of CXCL8+neutrophils and CD16-monocytes with high expression of IL1 B and CXCL8 in CBMC of GDM offspring was 3 times higher than that of the control group,indicating that GDM activates innate immunity in offspring.Moreover,these two types of innate immune cells showed enhanced interaction in inflammatory signaling pathways.The higher expression of IL-8 and IL-1β in monocytes from GDM cord blood was further confirmed in the validation cohort,and their adhesion and phagocytosis abilities were also significantly increased.Correlation analysis and in vitro stimulation test suggest that mild hyperglycemia may act as an adverse intrauterine environmental exposure factor,leading to a hyperinflammatory state of fetal immune cells.Further analysis revealed a similar transcriptional profile between CXCL8+IL1B+inflammatory monocytes in cord blood of GDM offspring and myeloid cells in unstable coronary plaques.(3)The effect of GDM on the age of monocyte immunity: Based on the data of the whole age group,we found that the inflammatory monocytes with high expression of CXCL8 and IL1 B were increased in the elderly;The immune age prediction model of monocytes was constructed on this basis,and it was found that different subsets of monocytes had different responses to aging.Further analysis showed that GDM had an additional effect on the immune age of monocytes,which could aggravate the senescence of monocytes.Conclusions: The main characteristics of cord blood immune cells are the immature and primitive stage of adaptive immune cells,and the weak immune defense ability and enhanced anti-inflammatory ability of innate immune cells.GDM can negatively affect fetal immune homeostasis,lead to enhanced inflammation of the innate immune system and aggravate the immune aging of monocytes,which may be the potential mechanism by which GDM increases the risk of abnormal lipid metabolism in offspring,and then promotes the occurrence and development of atherosclerosis. |
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