Royal jelly (RJ) is a naturally occurring substance synthesized by honeybees and has various health benefits. Herein, we focused on the medium-chain fatty acids (MCFAs) unique to RJ and evaluated their therapeutic efficacy in treating non-alcoholic fatty liver disease (NAFLD). We examined db/m mice that were exclusively fed a normal diet, db/db mice exclusively fed a normal diet, and db/db mice fed varying RJ quantities (0.2, 1, and 5%). RJ improved NAFLD activity scores and decreased gene expression related to fatty acid metabolism, fibrosis, and inflammation in the liver. RJ regulated innate immunity-related inflammatory responses in the small intestine and decreased the expression of genes associated with inflammation and nutrient absorption transporters. RJ increased the number of operational taxonomic units, the abundance of Bacteroides, and seven taxa, including bacteria that produce short-chain fatty acids. RJ increased the concentrations of RJ-related MCFAs (10-hidroxy-2-decenoic acid, 10-hydroxydecanoic acid, 2-decenedioic acid, and sebacic acid) in the serum and liver. These RJ-related MCFAs decreased saturated fatty acid deposition in HepG2 cells and decreased the gene expression associated with fibrosis and fatty acid metabolism. RJ and RJ-related MCFAs improved dysbiosis and regulated the expression of inflammation-, fibrosis-, and nutrient absorption transporter-related genes, thereby preventing NAFLD.

This study reports the use of single-cell RNA sequencing to evaluate B cells in the peripheral blood mononuclear cells (PBMCs) and intrathyroidal blood mononuclear cells of patients with Graves’ disease (GD) undergoing thyroidectomy. These cells were stimulated with overlapping peptides of thyroid autoantigens, including thyroid-stimulating hormone receptor (TSHR), thyroglobulin (Tg), and thyroid peroxidase (TPO). In PBMCs, naive B cells are characterized by IL6 and CXCR5, whereas memory B cells express IGHG1, IGHG2, and CD74. HLA-DMA, HLA-DRB1, IGHG, IGHM, CD74, CD79A, and MS4A1 expression increased in peptide-stimulated naive and memory B cells compared to those in the controls. Thyroid naive B cells are characterized by CD40 and TNFRSF13C, whereas memory B cells express IGHM, CD79A, and MS4A1. Thyroid B cells showed higher DUSP1, DUSP2, CD69, FOSB, RGS1, and immunoglobulin gene expression than control PBMCs and thyroid cells. B-cell receptor analysis revealed frequent IGHV3-23 and IGHV4-34 usage in controls, whereas IGHV4-34/IGHJ4 expression was increased in TSHR-stimulated groups. We concluded that B-cell responses to TSHR, Tg, and TPO differed and that changes in B-cell reactivity also occurred in PBMCs and the thyroid. Additionally, IGHV3-23 and IGHV4-34 may be associated with autoantibody production in GD.

This study explores the impact of royal jelly (RJ) on small intestinal epigenomic changes. RJ, produced by honeybees, is known for its effects on metabolic diseases. The hypothesis is that RJ induces epigenomic modifications in small intestinal epithelial cells, affecting gene expression and contributing to metabolic health. Male db/m and db/db mice were used to examine RJ’s effects through mRNA sequencing and CUT&Tag methods. This study focused on histone modifications and gene expression changes, with statistical significance set at p < 0.05. RJ administration improved insulin sensitivity and lipid metabolism without affecting body weight. GO and KEGG pathway analyses showed significant enrichment in metabolic processes, cellular components, and molecular functions. RJ altered histone modifications, increasing H3K27me3 and decreasing H3K23Ac in genes associated with the G2M checkpoint. These genes, including Smc2, Mcm3, Ccnd1, Rasal2, Mcm6, and Mad2l1, are linked to cancer progression and metabolic regulation. RJ induces beneficial epigenomic changes in small intestinal epithelial cells, improving metabolic health and reducing cancer-associated gene expression. These findings highlight RJ’s potential as a therapeutic agent for metabolic disorders. Further research is needed to fully understand the mechanisms behind these effects and their implications for human health.

Takahiro Tsujikawa and Shigeru Hirano were not included as authors in the original publication