FSLLRY-NH2, a protease-activated receptor 2 (PAR2) antagonist, activates mas-related G protein-coupled receptor C11 (MrgprC11) to induce scratching behaviors in mice.

AIMS: Protease-activated receptor 2 (PAR2), a type of G protein-coupled receptor (GPCR), plays a significant role in pathophysiological conditions such as inflammation. A synthetic peptide SLIGRL-NH2 (SLIGRL) can activate PAR2, while FSLLRY-NH2 (FSLLRY) is an antagonist. A previous study showed that SLIGRL activates both PAR2 and mas-related G protein-coupled receptor C11 (MrgprC11), a different type of GPCR expressed in sensory neurons. However, the impact of FSLLRY on MrgprC11 and its human ortholog MRGPRX1 was not verified. Hence, the present study aims to verify the effect of FSLLRY on MrgprC11 and MRGPRX1. METHODS: The calcium imaging technique was applied to determine the effect of FSLLRY in HEK293T cells expressing MrgprC11/MRGPRX1 or dorsal root ganglia (DRG) neurons. Scratching behavior was also investigated in wild-type and PAR2 knockout mice after injecting FSLLRY. KEY FINDINGS: It was surprisingly discovered that FSLLRY specifically activates MrgprC11 in a dose-dependent manner, but not other MRGPR subtypes. Furthermore, FSLLRY also moderately activated MRGPRX1. FSLLRY stimulates downstream pathways including Gαq/11, phospholipase C, IP3 receptor, and TRPC ion channels to evoke an increase in the intracellular calcium levels. The molecular docking analysis predicted that FSLLRY interacts with the orthosteric binding pocket of MrgprC11 and MRGPRX1. Finally, FSLLRY activated primary cultures of mouse sensory neurons, and induced scratching behaviors in mice. SIGNIFICANCE: The present study has revealed that FSLLRY is capable of triggering itch sensation through activation of MrgprC11. This finding highlights the importance of considering the unexpected activation of MRGPRs in future therapeutic approaches aimed at the inhibition of PAR2.

Association between lower parity and low muscle mass in postmenopausal women: data from KNHANES (2010-2011).

OBJECTIVE: This study aimed to investigate whether parity is associated with the prevalence of low muscle mass in postmenopausal women. METHODS: This study was performed using data from the 2010-2011 Korean National Health and Nutrition Examination Survey, which included 1,338 postmenopausal women aged 46 to 70 years. The association between parity and low muscle mass was analyzed after adjusting parity, multiparity, age, body mass index, diabetes mellitus, education level, and Homeostatic Model Assessment of Insulin Resistance and using weighted multiple logistic regression analysis. Modifiable risk factors were evaluated in a susceptible population. Low muscle mass was defined as an appendicular skeletal muscle mass index below 2 SDs with a cutoff value of 5.45 kg/m 2 . RESULTS: The low muscle mass group ( n = 343) had lower parity, lower body mass index, more frequent previous history of diabetes mellitus, higher Homeostatic Model Assessment of Insulin Resistance, and higher education level compared with the non-low muscle mass group ( n = 995). After adjusting for the confounding factors, parity with three births or more was associated with a significantly lower odds of postmenopausal low muscle mass than nulliparity (model 1: odds ratio, 0.32; 95% confidence interval, 0.12-0.87; P = 0.03; model 2: odds ratio, 0.27; 95% confidence interval, 0.11-0.67; P < 0.05). In the subgroup analysis of the lower parity group, moderate aerobic activity was associated with a lower low muscle mass prevalence. CONCLUSIONS: A lower parity is associated with increasing the odds of low muscle mass in postmenopausal Korean women. Moderate aerobic activity may be effective in lowering the odds of low muscle mass in postmenopausal women with lower parity.

scTyper: a comprehensive pipeline for the cell typing analysis of single-cell RNA-seq data.

BACKGROUND: Recent advances in single-cell RNA sequencing (scRNA-seq) technology have enabled the identification of individual cell types, such as epithelial cells, immune cells, and fibroblasts, in tissue samples containing complex cell populations. Cell typing is one of the key challenges in scRNA-seq data analysis that is usually achieved by estimating the expression of cell marker genes. However, there is no standard practice for cell typing, often resulting in variable and inaccurate outcomes. RESULTS: We have developed a comprehensive and user-friendly R-based scRNA-seq analysis and cell typing package, scTyper. scTyper also provides a database of cell type markers, scTyper.db, which contains 213 cell marker sets collected from literature. These marker sets include but are not limited to markers for malignant cells, cancer-associated fibroblasts, and tumor-infiltrating T cells. Additionally, scTyper provides three customized methods for estimating cell-type marker expression, including nearest template prediction (NTP), gene set enrichment analysis (GSEA), and average expression values. DNA copy number inference method (inferCNV) has been implemented with an improved modification that can be used for malignant cell typing. The package also supports the data preprocessing pipelines by Cell Ranger from 10X Genomics and the Seurat package. A summary reporting system is also implemented, which may facilitate users to perform reproducible analyses. CONCLUSIONS: scTyper provides a comprehensive and user-friendly analysis pipeline for cell typing of scRNA-seq data with a curated cell marker database, scTyper.db.

Lactobacillus plantarum LC27 and Bifidobacterium longum LC67 simultaneously alleviate high-fat diet-induced colitis, endotoxemia, liver steatosis, and obesity in mice.

Long-term feeding of a high-fat diet (HFD) induces endotoxemia and gastrointestinal inflammation by disturbing gut microbiota composition and membrane permeability, resulting in the acceleration of obesity. Some probiotics exhibit anti-inflammatory effects in vitro and in vivo. Therefore, we hypothesized that anti-inflammatory probiotics could lead to the simultaneous attenuation of endotoxemia, liver steatosis, obesity, and colitis in mice with HFD-induced obesity. Herein, we examined whether Lactobacillus plantarum LC27 and/or Bifidobacterium longum LC, which significantly suppressed NF-κB activation in lipopolysaccharide- or fecal lysate-stimulated Caco-2 cells, could simultaneously alleviate liver steatosis and colitis in mice with HFD-induced obesity. Oral administration of LC27, LC67, or their (3:1) mixture (LM) reduced HFD-induced aspartate transaminase, alanine transaminase, triglyceride, total cholesterol, and lipopolysaccharide levels in the blood and liver. Their treatments also suppressed HFD-induced NF-κB activation and increased AMP-activated protein kinase (AMPK) activation and claudin-1 and occludin expression in the liver and colon. Moreover, LC27, LC67, or LM treatment reduced HFD-induced Firmicutes and Proteobacteria populations in gut microbiota and fecal lipopolysaccharide production. The hypothesis was supported by the findings that anti-inflammatory LC27 and/or LC67 simultaneously alleviated liver steatosis, obesity, and colitis by regulating NF-κB and AMPK activation through the inhibition of gut microbiota lipopolysaccharide production.