Wenbo Zhou, Huiyan Wang, Yuqi Yang, Fang Guo, Bin Yu, and Zhaoliang Su. Mol. Cells 2022;45:317-28. https://doi.org/10.14348/molcells.2021.0211

Observational studies have revealed that metabolic disorders are closely related to the development of preeclampsia (PE). However, there is still a research gap on the causal role of metabolites in promoting or preventing PE. We aimed to systematically explore the causal association between circulating metabolites and PE. Single nucleotide polymorphisms (SNPs) from genome-wide association study (GWAS) of 486 blood metabolites (7,824 participants) were extracted as instrumental variables (P < 1 × 10− 5), GWAS summary statistics for PE were obtained from FinnGen consortium (7,212 cases and 194,266 controls) as outcome, and a two-sample Mendelian randomization (MR) analysis was conducted. Inverse variance weighted (IVW) was set as the primary method, with MR–Egger and weighted median as auxiliary methods; the instrumental variable strength and confounding factors were also assessed. Sensitivity analyses including MR-Egger, Cochran’s Q test, MR-PRESSO and leave-one-out analysis were performed to test the robustness of the MR results. For significant associations, repeated MR and meta-analysis were performed by another metabolite GWAS (8,299 participants). Furthermore, significantly associated metabolites were subjected to a metabolic pathway analysis. The instrumental variables for the metabolites ranged from 3 to 493. Primary analysis revealed a total of 12 known (e.g., phenol sulfate, citrulline, lactate and gamma-glutamylglutamine) and 11 unknown metabolites were associated with PE. Heterogeneity and pleiotropy tests verified the robustness of the MR results. Validation with another metabolite GWAS dataset revealed consistency trends in 6 of the known metabolites with preliminary analysis, particularly the finding that genetic susceptibility to low levels of arachidonate (20:4n6) and citrulline were risk factors for PE. The pathway analysis revealed glycolysis/gluconeogenesis and arginine biosynthesis involved in the pathogenesis of PE. This study identifies a causal relationship between some circulating metabolites and PE. Our study presented new perspectives on the pathogenesis of PE by integrating metabolomics with genomics, which opens up avenues for more accurate understanding and management of the disease, providing new potential candidate metabolic molecular markers for the prevention, diagnosis and treatment of PE. Considering the limitations of MR studies, further research is needed to confirm the causality and underlying mechanisms of these findings.

Objective: This study aimed to establish a cell-free fetal DNA (cffDNA) assay using multiplex digital PCR (dPCR) for identifying fetuses at increased risk of 22q11.2 deletion/duplication syndrome. Methods: Six detection sites and their corresponding probes were designed for the 22q11.2 recurrent region. A dPCR assay for the noninvasive screening of 22q11.2 deletion/duplication syndrome was established. A total of 130 plasma samples from pregnant women (including 15 samples with fetal 22q11.2 deletion/duplication syndrome) were blindly tested for evaluating the sensitivity and specificity of the established assay. Results: DNA with different sizes of 22q11.2 deletion/duplication was detected via dPCR, indicating that the designed probes and detection sites were reasonable and effective. In the retrospective clinical samples, 11 out of 15 samples of pregnant women with 22q11.2 deletion/duplication were detected during the cffDNA assay, and accurate regional localization was achieved. Among the 115 normal samples, 111 were confirmed to be normal. Receiver operating characteristic curves were used for assessing the cut-off values and AUC for these samples. The sensitivity, specificity, and positive as well as negative predictive values were 73.3%, 96.5%, 73.3%, and 96.5%, respectively. Conclusion: The cffDNA assay based on dPCR technology for the noninvasive detection of 22q11.2 recurrent copy number variants in fetuses detected most affected cases, including smaller but relatively common nested deletions, with a low false-positive rate. It is a potential, efficient and simple method for the noninvasive screening of 22q11.2 deletion/duplication syndrome.

Gestational diabetes mellitus (GDM) will bring the increased risk of adverse pregnancy outcomes. More and more evidence showed that placentation defects might play important role in GDM. However, it is still very limited of our understanding in human placenta. This study fiestly generated a comprehensive transcriptomic profile of cellular signifures and transcriptomes of human placenta in GDM by single-cell RNA-sequencing (scRNA-seq), built a comprehensive cell atlas, exploded the cell identities and cell-type-specific marker genes. In addition, it demonstrated the features of placental function and cell interactions for GDM. All these will contrubute to reveal the new molecular mechanism of GDM, and develop innovation to prevent GDM.

Observational studies suggest that blood lipids are a risk factor for uterine fibroids (UFs) and that lipid-lowering drugs are beneficial for the treatment and prevention of UF; however, the conclusions are inconsistent. We aimed to determine the causal effects of lipids and lipid-lowering drugs on UFs using Mendelian randomization (MR). Genetic variants from genome-wide association studies (GWAS) of lipid traits and variants in genes encoding lipid-lowering drug targets were extracted, and two independent UF GWAS were set as the outcome. Their effects on UF risk and related traits were estimated using the inverse variance weighted method. The MR analysis revealed that high density lipoprotein cholesterol (HDL-C, OR = 0.88, 95 % CI: 0.83-0.93, P = 3.58E-6) and triglycerides (TG, OR = 1.14, 95 % CI: 1.07-1.21, P = 6.83E-5) were protective factors and risk factors for UF, respectively. Drug-targeted MR analysis results indicated that genetically predicted inhibition of cholesteryl ester transfer protein (CETP) was associated with a lower UF risk (OR = 0.95, 95 % CI: 0.92-0.98, P = 7.83E-4), as well as reduced levels or risk of other UF-associated clinical traits, including estradiol level, excessive menstruation, abdominal and pelvic pain, myomectomy, and miscarriage. Our study provides evidence that HDL-C and TG levels were causally associated with UF risk. Genetically proxied CETP inhibition may have a protective effect against UF, which warrants further investigation.