Multiple knockout mouse and embryonic stem cell models reveal the role of miR-124a in neuronal maturation.

MicroRNA-124a (miR-124a) is one of the most abundantly expressed microRNAs in the central nervous system and is encoded in mammals by the three genomic loci miR-124a-1/2/3; however, its in vivo roles in neuronal development and function remain ambiguous. In the present study, we investigated the effect of miR-124a loss on neuronal differentiation in mice and in embryonic stem (ES) cells. Since miR-124a-3 exhibits only background expression levels in the brain and we were unable to obtain miR-124a-1/2/3 triple knockout (TKO) mice by mating, we generated and analyzed miR-124a-1/2 double knockout (DKO) mice. We found that these DKO mice exhibit perinatal lethality. RNA-seq analysis demonstrated that the expression levels of proneural and neuronal marker genes were almost unchanged between the control and miR-124a-1/2 DKO brains; however, genes related to neuronal synaptic formation and function were enriched among downregulated genes in the miR-124a-1/2 DKO brain. In addition, we found the transcription regulator Tardbp/TDP-43, loss of which leads to defects in neuronal maturation and function, was inactivated in the miR-124a-1/2 DKO brain. Furthermore, Tardbp knockdown suppressed neurite extension in cultured neuronal cells. We also generated miR-124a-1/2/3 TKO ES cells using CRISPR-Cas9 as an alternative to TKO mice. Phase-contrast microscopic, immunocytochemical, and gene expression analyses showed that miR-124a-1/2/3 TKO ES cell lines were able to differentiate into neurons. Collectively, these results suggest that miR-124a plays a role in neuronal maturation rather than neurogenesis in vivo and advance our understanding of the functional roles of microRNAs in central nervous system development.

Comparison of three classification systems of Prepregnancy Body Mass Index with Perinatal Outcomes in Japanese Obese Pregnant Women: A retrospective study at a single center.

In Japan, pregnant women are diagnosed as obese if the prepregnancy body mass index (BMI) is ≥25 kg/m2. However, this is different from other countries. The Institute of Medicine (IOM) classifies prepregnancy BMI as underweight (BMI <18.5 kg/m2), normal weight (BMI 18.5-24.9 kg/m2), overweight (BMI 25.0-29.9 kg/m2), and obese (BMI ≥30 kg/m2). In addition to these four categories, the American College of Obstetricians and Gynecologists (ACOG) classifies prepregnancy BMI as obesity class I (BMI 30.0-34.9 kg/m2), obesity class II (BMI 35.0-39.9 kg/m2), and obesity class III (BMI ≥40 kg/m2). We conducted a retrospective cohort study to compare obstetric outcomes by the three different categorizations in 6,066 pregnant women who gave birth between 2010 and 2019. According to Japanese classification, 668 (11%) pregnant women were classified as obese, and significant odds ratios (OR) were observed for hypertensive disorders of pregnancy (HDP; 3.32), gestational diabetes mellitus (GDM; 3.39), large for gestational age (LGA; 2.91), and macrosomia (4.01). According to the classification of IOM, 474 (7.8%) and 194 (3.1%) were classified as overweight and obese pregnant women, respectively. Specifically, a high OR was observed in obese pregnant women for HDP (5.85) and GDM (5.0). ACOG classification categorized 474 (7.8%) pregnant women as overweight, 141 (2.3%) as obesity class I, 41 (0.6%) as obesity class II, and 12 (0.2%) as obesity class III. In obesity class III, a significantly high OR was observed for HDP (12.89), GDM (8.37), and LGA (5.74). The Japanese classification may be useful for low-risk pregnancies, whereas IOM classification may be applicable to identify high-risk pregnancies. ACOG criteria may be useful for step-wise assessments of HDP and GDM risks in Japanese pregnant women; however, the number of class II and III obese pregnant women was small.