miR-330-5p in Small Extracellular Vesicles Derived From Plastrum testudinis-Preconditioned Bone Mesenchymal Stem Cells Attenuates Osteogenesis by Modulating Wnt/β-Catenin Signaling

The bone microenvironment is crucial for the growth and development of different types of osteocytes. Small extracellular vesicles (sEVs) secreted by bone mesenchymal stem cells are delivered to target cells where their contents regulate biological functions. Here, we evaluated the osteogenic effects and mechanism of sEVs derived from Plastrum testudinis-preconditioned bone mesenchymal stem cells (PT-sEV). The osteogenic effects of PT-sEV were evaluated by the differentiation of osteoblasts and the alternation of bone quality and quantity in ovariectomized rats. The specific mechanism was explored by high-throughput sequencing and verified by transfection with the corresponding miRNA mimic and inhibitor. RNA-sequence identified a unique enrichment of a set of miRNAs in PT-sEV compared with sEVs derived from untreated BMSCs. Overexpression or inhibition in vitro indicated that the osteogenic inducing potential of sEVs was mainly attributable to miR-330-5p, one of the most dramatically downregulated miRNAs in the PT-sEV fraction. Dual luciferase reporter assays showed that miR-330-5p negatively regulated osteogenesis by directly binding to the 3′ untranslated region of Tnc. Additional experiments showed that Tnc regulated Wnt/β-catenin signaling, and rescue experiment showed that miR-330-5p could restore β-catenin expression; additionally, animal experiments indicated that Wnt signaling was inactivated in the ovariectomized rats. These data demonstrated the regenerative potential of PT-sEV, which induced osteogenic differentiation of pre-osteoblasts, leading to bone formation. This process was achieved by delivering miR-330-5p, which regulated Tnc to control Wnt/β-catenin signaling.

Changes in Bone Metabolism and Antioxidant Defense Systems in Menopause-Induced Rats Fed Bran Extract from Dark Purple Rice (Oryza sativa L. Cv. Superjami)

Menopause is a matter of concern for women’s health due to a deficiency of female hormones; additionally, reactive oxygen species and aging can cause osteoporosis. Food becomes increasingly interesting as a menopausal woman’s alternative to hormone therapy. The effects of ethanol extracts from dark purple Superjami rice bran on bone metabolism and antioxidant defense systems in menopause-induced animal models were evaluated. Female rats underwent sham surgery or were ovariectomized to induce a menopause-like state. Rats were divided into a sham control group (SHAM), an ovariectomized control group (OVX), and an ovariectomized grou supplemented with Superjami rice bran extract group (OVX-S) and fed for 8 weeks. The OVX groups exhibited significantly more weight gain, amounts of bone turnover biochemical markers (alkaline phosphatase, osteocalcin, and C-terminal telopeptide), bone loss, lipid-peroxidation and oxidative stress than the SHAM group. However, Superjami bran extract added to the diet resulted in a significant reduction in body weight and lipid peroxidation, as well as enhanced bone metabolism and antioxidant enzyme activities, in ovariectomized rats. These results propound that extracts from Superjami rice bran have therapeutic potentiality against bone loss and oxidative stress in menopause-induced states and will be useful in preventing postmenopausal osteoporosis and oxidative damage.

Effect of Germinated Pigmented Rice "Superjami" on the Glucose Level, Antioxidant Defense System, and Bone Metabolism in Menopausal Rat Model

Women experience physical, mental, and social changes during menopause. It is important to maintain a healthy diet for effective menopause management. The effect of germinated Superjami, a deep violet colored rice cultivar, on the body weight, glucose level, antioxidant defense system, and bone metabolism in a menopausal rat model was investigated. The animals were randomly divided into three groups and fed with a normal diet (ND), a control diet supplemented with 20% (w/w) non-germinated Superjami flour (NGSF), or germinated Superjami flour (GSF) for eight weeks. The NGSF and GSF groups exhibited significantly lower body weight and fat, glucose and insulin contents, adipokine concentrations, and bone resorption biomarker levels, and higher antioxidant enzyme activities and 17-β-estradiol content than the ND group (p < 0.05). The GSF group showed greater glucose homeostasis, antioxidative, and bone metabolism-improving effects compared with the NGSF group. These findings demonstrate that germination could further improve the health-promoting properties of Superjami and that this germinated pigmented rice cultivar could be useful in the treatment and management of menopause-induced hyperglycemia, oxidative stress, and bone turnover imbalance.

Anthocyanins from purple corn activate free fatty acid-receptor 1 and glucokinase enhancing in vitro insulin secretion and hepatic glucose uptake

The objective of this study was to evaluate the ability of anthocyanins (ANC) present in purple corn to enhance insulin secretion and hepatic glucose uptake in pancreatic cells and hepatocytes, through activation of the free fatty acid receptor-1 (FFAR1) and glucokinase (GK), respectively. Using a dual-layer cell culture with Caco-2 cells, INS-1E or HepG2 cells were treated with an anthocyanin-rich extract from the pericarp of purple corn (PCW), as well as pure ANC cyanidin-3-O-glucoside (C3G), peonidin-3-O-glucoside, pelargonidin-3-O-glucoside. Delphinidin-3-O-glucoside (D3G) was used for comparative purposes. Semipurified C3G (C3G-P) and condensed forms (CF-P) isolated from PCW were also used. At 100 μM, the pure ANC enhanced glucose-stimulated insulin secretion (GSIS) in INS-1E cells ranging from 18% to 40% (p<0.05) compared to untreated cells. PCW increased GSIS by 51%. D3G was the most effective anthocyanin activating FFAR1 (EC50: 196.6 μM). PCW had activating potential on FFAR1 (EC50: 77 μg/mL). PCW, as well as C3G and D3G increased the expression of FFAR1, PLC, and phosphorylation of PKD, related to the FFAR1-dependent insulin secretory pathway. The treatment with 100 μM of P3G and C3G increased (p<0.05) glucose uptake in HepG2 cells by 19% and 31%. PCW increased the glucose uptake in HepG2 cells by 48%. It was determined that CF-P was the most effective for activating GK (EC50: 39.9 μM) and the PCW extracts had an efficacy of EC50: 44 μg/mL. The ANC in purple corn also reduced AMPK phosphorylation and PEPCK expression in HepG2 cells, known to be related to reduction in gluconeogenesis. It is demonstrated for the first time that dietary ANC can enhance the activity of novel biomarkers FFAR1 and GK and potentially ameliorate type-2 diabetes comorbidities.