Central 5-HTR2C in the Control of Metabolic Homeostasis.

The 5-hydroxytryptamine 2C receptor (5-HTR2C) is a class G protein-coupled receptor (GPCR) enriched in the hypothalamus and the brain stem, where it has been shown to regulate energy homeostasis, including feeding and glucose metabolism. Accordingly, 5-HTR2C has been the target of several anti-obesity drugs, though the associated side effects greatly curbed their clinical applications. Dissecting the specific neural circuits of 5-HTR2C-expressing neurons and the detailed molecular pathways of 5-HTR2C signaling in metabolic regulation will help to develop better therapeutic strategies towards metabolic disorders. In this review, we introduced the regulatory role of 5-HTR2C in feeding behavior and glucose metabolism, with particular focus on the molecular pathways, neural network, and its interaction with other metabolic hormones, such as leptin, ghrelin, insulin, and estrogens. Moreover, the latest progress in the clinical research on 5-HTR2C agonists was also discussed.

Pseudotime Ordering Single-Cell Transcriptomic of ß Cells Pancreatic Islets in Health and Type 2 Diabetes.

ß cells are defined by the ability to produce and secret insulin. Recent studies have evaluated that human pancreatic ß cells are heterogeneous and demonstrated the transcript alterations of ß cell subpopulation in diabetes. Single-cell RNA sequence (scRNA-seq) analysis helps us to refine the cell types signatures and understand the role of the ß cells during metabolic challenges and diseases. Here, we construct the pseudotime trajectory of ß cells from publicly available scRNA-seq data in health and type 2 diabetes (T2D) based on highly dispersed and highly expressed genes using Monocle2. We identified three major states including 1) Normal branch, 2) Obesity-like branch and 3) T2D-like branch based on biomarker genes and genes that give rise to bifurcation in the trajectory. ß cell function-maintain-related genes, insulin expression-related genes, and T2D-related genes enriched in three branches, respectively. Continuous pseudotime spectrum might suggest that ß cells transition among different states. The application of pseudotime analysis is conducted to clarify the different cell states, providing novel insights into the pathology of ß cells in T2D. Supplementary Information: The online version contains supplementary material is available at 10.1007/s43657-021-00024-z.

Dynamic changes of phenolic compounds during artificial aging of soybean seeds identified by high-performance liquid chromatography coupled with transcript analysis.

Phenolic compounds are important bioactive substances in plants, but study of their alteration during soybean seed aging is still limited. In this study, we conducted artificial aging on soybean seeds, detected the dynamic changes of phenolic compound concentrations using high-performance liquid chromatography, and analyzed the gene expression of key enzymes of phenolic metabolism. A detailed method for detection of 19 phenolic compounds during artificial aging of soybean seeds was constructed, and all of these phenols significantly changed in concentration. The content of protocatechuic acid, rutin, and morin decreased, whereas that of daidzein, glycitein, genistein, and baicalin increased. The concentration of caffeic acid, epicatechin, ferulic acid, daidzin, genistin, and resveratrol first rose and then declined, and the content of ferulic acid was highest after 2 days of artificial aging, with the other five phenolic compounds showing the highest content after 4 days of artificial aging. The total content of the 19 phenolic compounds reached a peak of 2357.43 µg g-1 dry weight at 2 days. Relative expression of PAL1, PAL2, PAL3, CHS7, CHS8, IFS1, IFS2, CHR1, 4CL2, C4H, and CHI2 was mostly downregulated as the duration of artificial aging increased. This study provides novel insights into the storage and use of soybean seed resources. Graphical abstract.