Keratinocytes, the major cell types of the epidermis, proliferate and migrate during wound healing to restore the epithelial barrier. Royal jelly is a traditional remedy used in wound repair. Our previous study found that the mixture of major royal jelly protein (MRJP) 2, 3 and 7 exhibited in vitro wound healing-promoting effects; however, the exact functional constituents and the associated underlying mechanisms of action are still largely unknown. In this study, a partial fragment of MRJP3 was recombinantly expressed as a fusion protein MRJP3-C113-Fc which promoted wound healing in vitro and in vivo. By employing protein inhibitors and immunoblots technology, it was initially found that the wound-repairing mechanisms of MRJP3-C113-Fc were correlated to the activation of EGFR/AKT/mTOR signaling pathway in keratinocytes (HaCaT cells). LC-MS/MS-based proteomic analysis demonstrated that the proteins present in the MRJP3-C113-Fc-treated HaCaT cells were different from the untreated ones, in which rhomboid 5 homolog 2 (RHBDF2) might be the potential regulator for the EGFR/AKT/mTOR signaling pathway. Silencing of RHBDF2 diminished the pro-proliferative and -migratory effectiveness of MRJP3-C113-Fc on HaCaT cells, as well as the phosphorylation of EGFR/AKT/mTOR, suggesting that the wound healing-promoting efficacy was attributable to the RHBDF2-mediated activation of EGFR/AKT/mTOR signaling pathway. Hence, this study is the first to discover the single fragment of MRJPs possessing pro-healing properties, and also the first to disclose the regulatory role of RHBDF2 in EGFR/AKT/mTOR signaling pathway-modulated wound healing. It will facilitate the development of MRJP3-C113-based therapeutic agent for skin wounds, and provide a novel target for treating cutaneous trauma.

In this study, pancrelipase inhibitory peptides (PES) from an enzymatic protein hydrolysate of Chlorella pyrenoidosa were isolated and purified by ultrafiltration and Sephadex gel chromatography. The in vivo hypolipidemic activity of PES was evaluated by fat deposition and the levels of triglyceride (TG) and total cholesterol (TC) in Caenorhabditis elegans fed a high sugar diet. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify the peptide sequence of PES, and molecular docking was used to select potential pancreatic lipase inhibitory peptides, and the pancreatic lipase inhibitory activity of the synthesized peptides was verified. The results showed that PES had good hypolipidemic activity at a concentration of 1 mg/mL; it inhibited lipid deposition by 22.5%, and reduced the levels of TG and TC by 27.4% and 29.4%, respectively. In total, 999 peptides were identified, and four potential lipase inhibitory peptides were obtained. Among them, FLGPF had the best inhibitory effect on pancreatic lipase, with an inhibition rate of 50.12% at 8 mg/mL. The inhibition was reversible and non-competitive, with an inhibition constant of 5.23 mg/mL. Molecular docking showed that FLGPF could better bind to human pancreatic triacylglycerol lipase (PTL) via π-hydrogen, π-cation and hydrogen bond interactions. This study can provide a theoretical reference for the development and utilization of C. pyrenoidosa protein-derived hypolipidemic peptide.

This research aimed to investigate the antidiabetic activity, underlying mechanisms, and gut microbiota regulation of aloin. The insulin-resistant HepG2 (IR-HepG2) cell model and the type 2 diabetic (T2D) mouse model were successfully established using dexamethasone and a high-fat high-sucrose diet with low-dose streptozotocin, respectively. Aloin intervention increased glucose consumption and stimulated the activity of hexokinase and pyruvate dehydrogenase in IR-HepG2 cells. Additionally, it diminished the weight loss, reduced fasting blood glucose levels and hemoglobin A1c activity, and promoted glucose tolerance and fasting serum insulin activity in T2D mice. Histopathological analysis of the liver indicated hepatic protection by aloin. Additionally, aloin treatment inhibited the protein expression of c-Jun N-terminal kinases and activated that of IRS1/PI3K/Akt in the liver. Moreover, aloin modulated the bacterial community in the gut by raising the abundance of Bacteroidota and reducing the richness of Firmicutes, Proteobacteria, and Actinobacteriota. Thus, aloin ameliorated IR via activating IRS1/PI3K/Akt signaling pathway and regulating the gut microbiota, and it may be promising candidate as functional food for diabetic therapy.

Grifola frondosa polysaccharide (GFP) as the natural compounds have been reported to exert diverse bioactivities. The aim of this study was to investigate the regulatory effects of GFP on intestinal microbiota in type 2 diabetic mice. The changes of microbiota in faeces of the diabetic mice upon high fat diet were determined and the V3 region of the 16S rRNA was sequenced by Illumina MiSeq high-throughput sequencing platform. Eighty operational taxonomic unit were identified to be shared by all samples, and the quality and richness of sequencing were assessed via rarefaction and rank abundance curves. The diversity of gut flora was slightly improved in diabetic mice after GFP treatment. The composition and relative abundance of gut microbiota at phylum and genus levels were altered by GFP. The abundance of Robinsoniella, Flavonifractor, Anaerotruncus, and Desulfvibrio were found to concentrate on diabetic mice through LEfSe analysis. Furthermore, Alloprevotella and Burkholderia had strong relevancy with other gut flora. Based on the findings, GFP might be a desired candidate on ameliorating the intestinal unbalance in diabetes.