Fructus Arctii (great burdock achene) is the dried ripe fruit of Arctium lappa L. (family Asteraceae) and is included in the Chinese pharmacopoeia. It has been reported that the clinical use of Fructus Arctii resulted in a satisfactory hypoglycemic effect in diabetic patients. This study aimed to investigate antidiabetic activity and mechanism of total lignans from Fructus Arctii (TLFA) in KKAy mice, a spontaneous Type 2 diabetic rodent model that exhibits marked obesity. In this study, KKAy mice were gavaged once daily with solvents (0.5% sodium carboxymethyl cellulose), TLFA (250 and 125 mg/kg), or metformin (200 mg/kg) for 11 weeks, and C57BL/6J mice treated with saline solution (0.9%, w/v) were used as normal control. The results indicate that TLFA has dual effects of hypoglycemia and weight loss, and administration of TLFA in KKAy mice could decrease fasting blood glucose, glycated hemoglobin, and body weight; improve oral glucose tolerance; increase high density lipoprotein cholesterol; and decrease triglycerides and free fatty acid in mice serum. Its efficacy may associate with multiple mechanisms of action such as stimulation of insulin secretion, activation of phosphatidylinositol 3-kinase/protein kinase B, and adenosine-monophosphate-activated protein kinase signaling pathway, decreasing leptin.
Purpose: Nanoparticles (NPs) decorated with functional ligands are promising candidates for cancer diagnosis and treatment. However, numerous studies have shown that chemically coupled targeting moieties on NPs lose their targeting capability in the biological milieu because they are shielded or covered by a "protein corona". Herein, we construct a functional magnetosome that recognizes and targets cancer cells even in the presence of protein corona. Methods: Magnetosomes (BMPs) were extracted from magnetotactic bacteria, M. gryphiswaldense (MSR-1), and decorated with trastuzumab (TZ) via affibody (RA) and glutaraldehyde (GA). The engineered BMPs are referred to as BMP-RA-TZ and BMP-GA-TZ. Their capacities to combine HER2 were detected by ELISA, the quantity of plasma corona proteins was analyzed using LC-MS. The efficiencies of targeting SK-BR-3 were demonstrated by confocal laser scanning microscopy and flow cytometry. Results: Both engineered BMPs contain up to ~0.2 mg TZ per mg of BMP, while the quantity of HER2 binding to BMP-RA-TZ is three times higher than that binding to BMP-GA-TZ. After incubation with normal human plasma or IgG-supplemented plasma, GA-TZ-containing BMPs have larger hydrated radii and more surface proteins in comparison with RA-TZ-containing BMPs. The TZcontaining BMPs all can be targeted to and internalized in the HER2-overexpressing breast cancer cell line SK-BR-3; however, their targeting efficiencies vary considerably: 50-75% for RA-TZ-containing BMPs and 9-19% for GA-TZ-containing BMPs. BMPs were incubated with plasma (100%) and cancer cells to simulate human in vivo environment. In this milieu, BMP-RA-TZ uptake efficiency of SK-BR-3 reaches nearly 80% (slightly lower than for direct interaction with BMP-RA-TZ), whereas the BMP-GA-TZ uptake efficiency is <17%. Conclusion: Application of the RA scaffold promotes and orients the arrangement of targeting ligands and reduces the shielding effect of corona proteins. This strategy improves the targeting capability and drug delivery of NP in a simulated in vivo milieu.
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