Pregnancy necessitates various metabolic adjustments to ensure sufficient energy supply for the growth and development of the fetus. Maternal systems may experience maladaptation to pregnancy, leading to metabolic abnormalities such as GDM. GDM is a prevalent complication of pregnancy, and recent studies indicate that adiponectin plays a crucial role in regulating overall energy balance, including the maintenance of a healthy pregnancy and the adaptive metabolic response to pregnancy[39]. Systems biology assessments using multi-omics analyses have demonstrated significant utility in identifying disease-associated molecules and their underlying mechanisms. However, to date, there has been a lack of comprehensive analysis examining the multi-dimensional molecular signatures of ADIPOQ in GDM. In this study, we examined the association between SNPs rs266729 and rs1501299 on ADIPOQ and the GDM cohort in the northern Han Chinese population. Furthermore, we investigated the ADIPOQ-mediated signaling pathways associated with GDM from a multi-omics perspective.
The ADIPOQ gene contains SNPs that potentially impact adiponectin expression in pregnancy through their influence on RNA splicing and stability[40]. Notably, the SNPs rs1501299 located in intron 2 and rs266729 in the promoter region have garnered attention in studies investigating the potential influence of genetic variability at this locus on the metabolic phenotypes of gestational diabetes mellitus (GDM). However, the conclusions drawn from these studies have been subject to dispute, particularly regarding the extent to which GDM risk is affected by the aforementioned SNPs[41]. A previous meta-analysis has reported no significant associations between the rs1501299 polymorphism and the risk of GDM[42].
In our previous study, an association was observed between the genotypes of rs1501299 and rs266729 and blood pressure in GDM[21]. In the present study, we conducted further analysis to examine the relationship between the distribution characteristics of rs1501299 and rs266729 genotypes and fetal umbilical artery flow parameters. Our findings indicate that GDM patients with the CC genotype of rs266729 and the GG genotype of rs1501299 exhibited a higher S/D ratio compared to the control group. Additionally, GDM patients with the GG genotype of rs1501299 and the CC genotype of rs266729 showed a lower Vd. The results indicate that the genetic variations rs1501299 and rs266729 in the ADIPOQ gene may have an impact on the resistance of blood vessels. The research conducted by Christina et al. demonstrates that the rs1501299 and rs2241766 variants of the ADIPOQ gene play a significant role in determining the levels of interleukin 6 (IL-6), intercellular cell adhesion molecule-1 (ICAM-1), and vascular endothelial growth factor (VEGF) in individuals with type 2 diabetes mellitus. These findings suggest a potential interaction between adiponectin, proinflammatory factors, and angiogenesis pathways, which could be crucial in the progression of both macrovascular and microvascular diseases.[43]. In this study, we aim to investigate the multifactorial nature of gestational diabetes mellitus (GDM) and its association with genetic and environmental factors. Specifically, we focus on the potential involvement of gene variants in the pathogenesis of GDM and their varying impact depending on other factors. To achieve this, we conducted further analyses to explore the role of the ADIPOQ gene in relation to GDM at various levels. It is worth noting that, to date, a complete set of transcriptome sequencing data encompassing circRNA, miRNA, lncRNA, and mRNA of GDM patients has not been identified. Therefore, in our analysis, we considered the changes in genes across different data sets and conducted a comprehensive multi-omics analysis.
The fundamental units of life are individual cells, and the analysis of single cells is a valuable approach for examining cellular heterogeneity in complex diseases. Prior research has shown that scRNA-seq can be employed to thoroughly characterize cellular heterogeneity, identify both known and unknown cell types and gene signatures specific to placental cells, uncover distinct cell subpopulations, and investigate transcription factors and potential intercellular communication patterns. Nevertheless, the majority of studies conducted thus far have not focused on diseases associated with pregnancy. In the present study, the expression of ADIPOQ was observed in nearly all cell types except for granulocytes in GDM. Cellchat analysis demonstrated robust interactions among these cells. Notably, the expression of ADIPOQ in granulocytes was relatively low, indicating a certain degree of cell specificity. Additionally, we conducted a comprehensive analysis of the cellular context in which ADIPOQ participated. Moreover, the cell locus analysis revealed that ADIPOQ and its mediated genes, including CPEB4, were associated with a cluster of cell development. In our single-cell analysis, it was observed that ADIPOQ exhibited expression in nearly all cell types, with the exception of granulocytes. ADIPOQ, an anti-inflammatory adipokine[44], has been associated with the risk factors of GDM, which is characterized by chronic low-grade inflammation[45]. During pregnancy, ADIPOQ levels decrease, and this decrease is further pronounced in individuals with GDM[16]. Given the known involvement of granulocytes in inflammation, it is plausible that their role in the inflammatory process may explain the absence of ADIPOQ expression in these cells.
The regulation of ADIPOQ mRNA expression is a multifaceted process, involving the identification of various transcription factors[46]. Typically, the expression of ADIPOQ is governed through multiple regulatory steps, including transcriptional and post-translational regulation. Initially, ncRNAs, which constitute a significant portion of transcribed DNA, were considered evolutionary debris due to their inability to encode proteins. However, as the functional roles of ncRNAs have been progressively elucidated, it has become evident that these molecules play a crucial role in intricately controlling the underlying molecular mechanisms. The ceRNA network was constructed using the miRNA network involving the participation of ADIPOQ genes. Our analysis in this study revealed that ADIPOQ exerts regulatory control over numerous genes, proteins, and pathways in GDM. Functional enrichment analysis further demonstrated the association of the ADIPOQ gene with response to nutrient levels and fat cell differentiation. It is worth noting that adipose tissue dysfunction is a characteristic feature observed in diabetic patients, as research has indicated a decrease in adipogenesis of preadipocytes in individuals with type 2 diabetes mellitus, ultimately resulting in ectopic fat storage[47]. Adipose differentiation may be regulated by ADIPOQ in GDM.
DNA methylation plays a significant role in the epigenetic regulation of gene expression in eukaryotes, independent of DNA sequence modification[48]. A growing body of evidence suggests that DNA methylation acts as a mediator between environmental stimuli and cellular responses. Furthermore, recent research indicates that DNA methylation is crucial for ADIPOQ transcription, with hypermethylation of the adiponectin promoter inhibiting adiponectin transcription[49, 50]. In our study, we discovered that ADIPOQ exhibits significant interactions with various proteins in both positive and negative regulatory networks, indicating its crucial involvement in gestational diabetes mellitus. Specifically, our methylation analysis revealed a negative correlation between ADIPOQ and the expression of MAPK9, NFκB1, and PRKAG1. Furthermore, the detrimental effects of MAPK9 and NFκB1 on islet function were observed, while hypermethylation of PRKAG1 was found to potentially disrupt key pathways and biological processes essential for pancreatic β-cell physiology[51, 52]. These findings suggest that ADIPOQ may exert a positive influence on GDM through its regulation of MAPK9, NFκB1 and PRKAG1 methylation levels.
This study aimed to comprehensively analyze the role of ADIPOQ in gestational diabetes mellitus (GDM). Initially, the relationship between ADIPOQ-related sites and fetal umbilical artery flow parameters in GDM was examined in the Chinese Han population. Subsequently, a ceRNA network mediated by ADIPOQ was constructed for GDM. Additionally, multi-omics analysis, including transcriptome, epigenome, and single-cell data analysis, was conducted to investigate the regulation of GDM by ADIPOQ. The findings of this study demonstrate that ADIPOQ plays a crucial role in GDM by modulating inflammatory and adipose-metabolism-related pathways, genes, and cellular expression. Moreover, ADIPOQ may serve as a potentially protective gene in the context of GDM.