Macrophage depletion disrupts immune balance and energy homeostasis.

Increased macrophage infiltration in tissues including white adipose tissue and skeletal muscle has been recognized as a pro-inflammatory factor that impairs insulin sensitivity in obesity. However, the relationship between tissue macrophages and energy metabolism under non-obese physiological conditions is not clear. To study a homeostatic role of macrophages in energy homeostasis, we depleted tissue macrophages in adult mice through conditional expression of diphtheria toxin (DT) receptor and DT-induced apoptosis. Macrophage depletion robustly reduced body fat mass due to reduced energy intake. These phenotypes were reversed after macrophage recovery. As a potential mechanism, severe hypothalamic and systemic inflammation was induced by neutrophil (NE) infiltration in the absence of macrophages. In addition, macrophage depletion dramatically increased circulating granulocyte colony-stimulating factor (G-CSF) which is indispensable for NE production and tissue infiltration. Our in vitro study further revealed that macrophages directly suppress G-CSF gene expression. Therefore, our study indicates that macrophages may play a critical role in integrating immune balance and energy homeostasis under physiological conditions

A novel method for crystalline silicon solar cells with low contact resistance and antireflection coating by an oxidized Mg layer

One of the key issues in the solar industry is lowering dopant concentration of emitter for high-efficiency crystalline solar cells. However, it is well known that a low surface concentration of dopants results in poor contact formation between the front Ag electrode and the n-layer of Si. In this paper, an evaporated Mg layer is used to reduce series resistance of c-Si solar cells. A layer of Mg metal is deposited on a lightly doped n-type Si emitter by evaporation. Ag electrode is screen printed to collect the generated electrons. Small work function difference between Mg and n-type silicon reduces the contact resistance. During a co-firing process, Mg is oxidized, and the oxidized layer serves as an antireflection layer. The measurement of an Ag/Mg/n-Si solar cell shows that Voc, Jsc, FF, and efficiency are 602 mV, 36.9 mA/cm2, 80.1%, and 17.75%, respectively. It can be applied to the manufacturing of low-cost, simple, and high-efficiency solar cells

Selective emitter using a screen printed etch barrier in crystalline silicon solar cell

The low level doping of a selective emitter by etch back is an easy and low cost process to obtain a better blue response from a solar cell. This work suggests that the contact resistance of the selective emitter can be controlled by wet etching with the commercial acid barrier paste that is commonly applied in screen printing. Wet etching conditions such as acid barrier curing time, etchant concentration, and etching time have been optimized for the process, which is controllable as well as fast. The acid barrier formed by screen printing was etched with HF and HNO(3) (1:200) solution for 15 s, resulting in high sheet contact resistance of 90 Ω/sq. Doping concentrations of the electrode contact portion were 2 × 10(21) cm(−3) in the low sheet resistance (Rs) region and 7 × 10(19) cm(−3) in the high Rs region. Solar cells of 12.5 × 12.5 cm(2) in dimensions with a wet etch back selective emitter J(sc) of 37 mAcm(−2), open circuit voltage (V(oc)) of 638.3 mV and efficiency of 18.13% were fabricated. The result showed an improvement of about 13 mV on V(oc) compared to those of the reference solar cell fabricated with the reactive-ion etching back selective emitter and with J(sc) of 36.90 mAcm(−2), V(oc) of 625.7 mV, and efficiency of 17.60%

Identification of novel factors in enterocytes involved in dietary fat absorption and energy balance

Obesity and obesity-related diseases are multifactorial diseases in which tissue to tissue communication is impaired. However, the role of metabolism within the intestine in these diseases has been largely ignored. Chylomicron secretion from the intestine is thought to depend primarily on the amount of dietary fat consumed because of its high efficiency. However, recent studies indicate that regulation of chylomicron secretion from the intestine affects postprandial triglyceride (TG) levels in the blood and even whole body energy balance. The purpose of these studies is to reveal the underappreciated roles of the intestine in TG and whole body energy metabolism during dietary fat absorption (DFA). Diaclyglycerol acyltrasferase (DGAT)-1 catalyzes the final, committed step of TG synthesis. DGAT1-/- mice are resistant to diet-induced obesity due in part to increased energy expenditure. DGAT1-deficient mice have abnormal TG storage in and delayed secretion of chylomicron from the intestine during DFA. However, the role of the intestine phenotype in the resistance to diet-induced obesity phenotype of DGAT1-/- mice is unknown. Therefore, in the first study, we examined whether the restoration of DGAT1 only in the intestine reverses the resistance of diet-induced obesity pheynotype in DGAT1-/- mice. We found that Dgat1IntONLY and DGAT1-/- mice completely lack or have abundant TG storage in CLDs in enterocytes, respectively. Despite lacking DGAT1 in liver and adipose tissue, we found that Dgat1IntONLY mice are not resistant to high-fat (HF) diet-induced hepatic steatosis or obesity, indicating that intestine specific DGAT1 expression in mice stimulates dietary TG secretion out of the enterocytes and thereby contributing to weight gain after HF diet feeding and is enough to reverse the phenotypes of DGAT1 -/- mice. Various studies imply that intestine may have a temporal TG storage during DFA, but it has been unclear. Therefore, in the second study, we examined the ability of the intestine to store TGs during DFA and found that enterocytes dynamically store TGs in cytoplasmic lipid droplets (CLDs). A dynamic pool of TG storage in enterocytes expands and depletes relative to time post dietary fat challenge. To identify cellular factors which may play a role in the regulation of the dynamic CLD storage, we investigated the expression and localization of PAT proteins, which are known to be related to CLD metabolism in various cell types, in enterocytes of mice chronically and acutely challenged by dietary fat. We found that adipophilin and Tip47 are the only PAT genes present in mouse intestinal mucosa and both genes are present at higher levels after HF challenges. In addition, TIP47, but not adipophilin, coats CLDs in enterocytes after an acute HF challenge suggesting that TIP47 plays a role in the synthesis of CLDs from newly synthesized TG at the beginning of the process of DFA in enterocytes. Adipophilin, on the other hand, coats CLDs only in enterocytes of chronic HF fed mice suggesting that adipophilin may play a role in the stabilization of TG stored in CLDs in longer term. These results suggest distinct roles for TIP47 and adipophilin in DFA. Taken together, these results highlight novel roles of the intestine during DFA. The intestine has a temporal storage of TGs as CLDs during dynamic process of DFA and the CLD metabolism may be in part regulated by TIP47 and adipophilin differently depending on the state of CLD maturation. In addition, the balance between CLD storage and TG secretion rate in and from the intestine play an important role in regulating whole body energy balance

Dietary Bioactive Compounds and Health

Foods primarily obtained from plant materials, such as fruits, vegetable, grains, legumes and other plant foods, provide not only nutrients but also non-nutrients [...

Brassinin Abundant in Brassicaceae Suppresses Melanogenesis through Dual Mechanisms of Tyrosinase Inhibition

Brassinin is a phytoalexin abundant in plants, especially in cabbage, and has been reported to act as an anti-cancer and anti-inflammatory agent. However, limited studies are available to elucidate the functionalities of brassinin. Here, we tested the effects of brassinin on melanogenesis using cell-free and cell-based biochemical analysis and docking simulation. Cell-free experiments exhibited that brassinin has antioxidant and anti-tyrosinase activities. When applied to B16F10 cells stimulated with a melanogenesis inducer α-MSH, brassinin pretreatment significantly reduced melanin accumulation and cellular tyrosinase activity. Docking simulation indicates that the docking score of brassinin to the binding pocket of tyrosinase is better than that of kojic acid or arbutin, anti-melanogenic positive controls, indicating that brassinin inhibits melanogenesis at least partially by binding to and inactivating tyrosinase. In addition, qPCR results showed that brassinin reduced tyrosinase mRNA levels. Together, these results suggest that brassinin exerts anti-melanogenesis effects by inhibiting both the activity and mRNA expression levels of tyrosinase. Therefore, our study showed that brassinin has the potential to be used in pharmaceutical or cosmetic products for depigmentation

Tight Junction in the Intestinal Epithelium: Its Association with Diseases and Regulation by Phytochemicals

The intestine plays an essential role in integrating immunity and nutrient digestion and absorption. Adjacent intestinal epithelia form tight junctions (TJs) that are essential to the function of the physical intestinal barrier, regulating the paracellular movement of various substances including ions, solutes, and water across the intestinal epithelium. Studies have shown that TJ dysfunction is highly associated with metabolic and inflammatory diseases. Thus, molecular and nutritional factors that improve TJ activity have gained attention in the pharmaceutical and medicinal fields. This review focuses on the association between TJ and diverse pathological conditions, as well as various molecular and nutritional interventions designed to boost TJ integrity

Recent Trends in Controlling the Enzymatic Browning of Fruit and Vegetable Products

Enzymatic browning because of polyphenol oxidases (PPOs) contributes to the color quality of fruit and vegetable (FV) products. Physical and chemical methods have been developed to inhibit the activity of PPOs, and several synthetic chemical compounds are commonly being used as PPO inhibitors in FV products. Recently, there has been an emphasis on consumer-oriented innovations in the food industry. Consumers tend to urge the use of natural and environment-friendly PPO inhibitors. The purpose of this review is to summarize the mechanisms underlying the anti-browning action of chemical PPO inhibitors and current trends in the research on these inhibitors. Based on their mechanisms of action, chemical inhibitors can be categorized as antioxidants, reducing agents, chelating agents, acidulants, and/or mixed-type PPO inhibitors. Here, we focused on the food ingredients, dietary components, food by-products, and waste associated with anti-browning activity