Search

Abnormal activation of adipogenesis in mesenchymal stem cells (MSCs) and preadipocyte cells is associated with human metabolic disorders, such as osteoporosis and obesity. This study investigated the biological effects of protocatechuic acid (PCA) on the modulation of osteogenesis and adipogenesis in cultured cells. PCA stimulation of MSCs significantly increased intracellular mineralization during osteogenesis, but reduced lipid accumulation in both MSCs and 3T3-L1 preadipocyte cells during adipogenesis. Reverse transcription-polymerase chain reaction and immunoblotting analyses showed a dose-dependent upregulation of proosteogenic runt-related transcription factor 2 due to induction of β-catenin. PCA reduced the expression of proadipogenic transcription factor, peroxisome proliferator-activated receptor-γ, and suppressed its promotor activity. These results suggest PCA exerts stimulatory effects on the osteogenesis of MSCs and inhibitory effects on the adipogenesis of MSCs and 3T3-L1 cells. PCA may contribute to maintain a coordinated metabolic balance between adipogenesis and osteogenesis, and thus may be useful for the prevention and alleviation of osteoporosis and obesity.

Vitamin C is a strong antioxidant that alters gene expression in cells, and its effects can be modified by cellular oxidative stress. We investigated the genome-wide effects of vitamin C on the in vivo transcriptome in the liver, which synthesizes various enzymes and proteins to defend against cellular oxidative stress. We fed mice vitamin C (0.056 mg/g of body weight) for 1 week and performed DNA microarray analysis with hepatic mRNA in fasting and refeeding states to mimic physiological conditions of oxidative stress. Significance analysis of microarray data identified approximately 6,000 genes differentially expressed in both fasting and refeeding states. In the fasting state, vitamin C induced overall energy metabolism as well as radical scavenging pathways. These were ameliorated in the refeeding state. These findings suggest that vitamin C has profound and immediate global effects on hepatic gene expression, which may help prevent oxidative stress, and that long-term treatment with vitamin C might reduce the risk of chronic disease.

Obesity is caused by an imbalance between caloric intake and energy expenditure and accumulation of excess lipids in adipose tissues. Recent studies have demonstrated that green tea and its processed products (e.g., oolong and black tea) are introduced to exert beneficial effects on lipid metabolism. Here, we propose that fermented green tea (FGT) extract, as a novel processed green tea, exhibits antiobesity effects. FGT reduced body weight gain and fat mass without modifying food intake. mRNA expression levels of lipogenic and inflammatory genes were downregulated in white adipose tissue of FGT-administered mice. FGT treatment alleviated glucose intolerance and fatty liver symptoms, common complications of obesity. Notably, FGT restored the changes in gut microbiota composition (e.g., the Firmicutes/Bacteroidetes and Bacteroides/Prevotella ratios), which is reported to be closely related with the development of obesity and insulin resistance, induced by high-fat diets. Collectively, FGT improves obesity and its associated symptoms and modulates composition of gut microbiota; thus, it could be used as a novel dietary component to control obesity and related symptoms.

We evaluated the protective effects of soy isoflavones (SIF) against osteoporosis in middle-aged ovariectomized (OVX) mice. SIF (30 mg/kg or 60 mg/kg) or 17β-estradiol (E2) was administered to OVX mice for 4 months after bilateral ovariectomy. We observed the biochemical markers of bone turnover, e.g., alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP), in serum. We also observed the bone mineral density (BMD) in femurs and lumbar vertebrae. In addition, we examined trabecular bone and interstitial cells in the femur using hematoxylin and eosin staining. The decrease in ALP levels and the increase in TRAP levels normally resulting from ovariectomy were suppressed by administration of 60 mg/kg SIF or E2. Administration of 60 mg/kg SIF or E2 also maintained the BMD, trabecular bone, and interstitial cells in OVX mice compared to those in pre-OVX mice. These results suggest that 60 mg/kg SIF effectively mitigates ovariectomy-induced osteoporosis in middle-aged mice.

The effects of soy phytoestrogens on Morris water maze (MWM) performance and neuronal cholinergic enzyme activities and immunoreactivity were studied in ovariectomized (OVX) rats. The rats were assigned to four groups fed control diet (CD), 3.9 mg/kg 17β-estradiol diet (E2), 263.4 mg/kg soy phytoestrogens diet (SP1), and 526.9 mg/kg soy phytoestrogens diet (SP2). In the MWM task, escape latency and path length were significantly less in the E2 and SP2 groups than in the CD group on the second day. Choline acetyltransferase (ChAT) activity in the cerebral cortex and ChAT immunoreactivity in the diagonal band of Broca were significantly greater in the E2, SP1, and SP2 groups than in the CD group. Acetylcholinesterase activity in the hippocampus in the E2, SP1, and SP2 groups was significantly lower than in the CD group. This study suggests that soy phytoestrogens affect the reference memory and neuronal cholinergic system in OVX rats.