Inhibitory effect of Bofutsushosan (Fangfengtongshengsan) extract on the absorption of fructose in rats and mice.

Bofutsushosan (BTS; fangfengtongshengsan in Chinese) is a formula in traditional Japanese Kampo and Chinese medicine comprising 18 crude drugs and used to treat obesity and metabolic syndrome. In our previous study, BTS boiling water extract inhibited the uptake of fructose absorbed via glucose transporter 5 into cultured cells. In this study, the inhibitory effect of BTS extract on the absorption of fructose from the intestine was investigated in vivo. The extract of BTS was orally administered to rats at doses equivalent to 25-fold of the daily dose for humans. One minute after sample administration, fructose was orally administered and blood samples were collected from the jugular vein 0.5, 1, 1.5, 2, and 4 h after the administration of fructose. The absorption of fructose from the intestine was significantly reduced by treatment with BTS extract, and this in vivo study reproduced previous in vitro results. Subsequently, the blood samples were collected from the portal vein 30 min after the oral administration of fructose in mice. BTS extract significantly reduced fructose absorption in mice, and compared the effect of modified BTS samples by removing one to several crude drugs from BTS. We found that the dried rhizome of Rheum palmatum (RR) significantly contributed to the inhibitory effect of BTS on fructose absorption. We found sennoside A to be the active ingredient of RR for the inhibition of fructose absorption, and that its effect almost saturated at a dose of 3 mg/kg. These results support the action mechanisms of BTS when used for the treatment of obesity in clinics and drug stores.

Carotenoid transporter CD36 expression depends on hypoxia-inducible factor-1α in mouse soleus muscles.

Dietary ß-carotene induces muscle hypertrophy and prevents muscle atrophy in red slow-twitch soleus muscles, but not in white fast-twitch extensor digitorum longus (EDL) muscles and gastrocnemius muscles. However, it remains unclear why these beneficial effects of ß-carotene are elicited in soleus muscles. To address this issue, we focused on carotenoid transporters in skeletal muscles. In mice, Cd36 mRNA levels were higher in red muscle than in white muscle. The siRNA-mediated knockdown of CD36 decreased ß-carotene uptake in C2C12 myotubes. In soleus muscles, CD36 knockdown inhibited ß-carotene-induced increase in muscle mass. Intravenous injection of the hypoxia marker pimonidazole produced more pimonidazole-bound proteins in soleus muscles than in EDL muscles, and the hypoxia-inducible factor-1 (HIF-1) α protein level was higher in soleus muscles than in EDL muscles. In C2C12 myotubes, hypoxia increased the expression of CD36 and HIF-1α at the protein and mRNA levels, and HIF-1α knockdown reduced hypoxia-induced increase in Cd36 mRNA level. In soleus muscles, HIF-1α knockdown reduced Cd36 mRNA level. These results indicate that CD36 is predominantly involved in ß-carotene-induced increase in soleus muscle mass of mice. Furthermore, we demonstrate that CD36 expression depends on HIF-1α in the soleus muscles of mice, even under normal physiological conditions.

Epidermal clearance of Candida albicans is mediated by IL-17 but independent of fungal innate immune receptors.

IL-17 plays important roles in host defense against Candida albicans at barrier surfaces and during invasive infection. However, the role of IL-17 in host defense after colonization of the epidermis, a main site of C. albicans infection, remains poorly understood. Using a murine model of epicutaneous candidiasis without skin abrasion, we found that skin inflammation triggered by epidermal C. albicans colonization was self-limiting with fungal clearance completed by day 7 after inoculation in wild-type mice or animals deficient in IL-17A or IL-17F. In contrast, marked neutrophilic inflammation in the epidermis and impaired fungal clearance were observed in mice lacking both IL-17A and IL-17F. Clearance of C. albicans was independent of Dectin-1, Dectin-2, CARD9 (caspase-recruitment domain family, member 9), TLR2 (Toll-like receptor 2) and MyD88 in the epidermal colonization model. We found that group 3 innate lymphoid cells (ILC3s) and γδT cells were the major IL-17 producers in the epicutaneous candidiasis model. Analyses of Rag2-/- mice and Rag2-/-Il2rg-/- mice revealed that production of IL-17A and IL-17F by ILC3s was sufficient for C. albicans clearance. Finally, we found that depletion of neutrophils impaired C. albicans clearance in the epidermal colonization model. Taken together, these findings indicate a critical and redundant function of IL-17A and IL-17F produced by ILC3s in host defense against C. albicans in the epidermis. The results also suggest that epidermal C. albicans clearance is independent of innate immune receptors or that these receptors act redundantly in fungal recognition and clearance.

Keratinocyte IL-36 Receptor/MyD88 Signaling Mediates Malassezia-Induced IL-17-Dependent Skin Inflammation.

BACKGROUND: Among skin commensal fungi, lipophilic Malassezia species exist on nearly all human skin surfaces. The pathophysiology of Malassezia-associated skin diseases remains poorly understood due in part to the lack of appropriate animal models. Our objective was to investigate the mechanisms underlying Malassezia-induced skin inflammation using a novel murine model that physiologically recapitulates Malassezia skin infection. METHODS: Mice were inoculated epicutaneously with Malassezia yeasts without barrier disruption and in the absence of external lipid supplementation. Skin inflammation, lesional fungal loads, and expression of cytokines and antimicrobial peptides were evaluated in wild-type and mutant mouse strains. RESULTS: Malassezia-induced skin inflammation and epidermal thickening were observed on day 4 after inoculation in wild-type mice. High fungal burdens were detected in the cornified layer on day 2 and decreased thereafter with near complete clearance by day 7 after inoculation. Malassezia-induced skin inflammation and fungal clearance by the host were interleukin-17 (IL-17) dependent with contribution of group 3 innate lymphoid cells. Moreover, IL-17-dependent skin inflammation was mediated through IL-36 receptor and keratinocyte MyD88 signaling. CONCLUSION: Using a new skin infection model, it is shown that Malassezia-induced IL-17- dependent skin inflammation and control of fungal infection are mediated via keratinocyte IL-36 receptor/MyD88 signaling.

Daidzein down-regulates ubiquitin-specific protease 19 expression through estrogen receptor ß and increases skeletal muscle mass in young female mice.

Ubiquitin-specific protease 19 (USP19) is a key player in the negative regulation of muscle mass during muscle atrophy. Loss-of-function approaches demonstrate that 17ß-estradiol (E2) increases USP19 expression through estrogen receptor (ER) α and consequently decreases soleus muscle mass in young female mice under physiological conditions. Daidzein is one of the main isoflavones in soy, and activates ERß-dependent transcription. Here, we investigated the effects of daidzein on E2-increased USP19 expression and E2-decreased soleus muscle mass in young female mice. Daidzein stimulated the transcriptional activity of ERß in murine C2C12 cells and down-regulated USP19 expression. Consistently, daidzein inhibited E2-induced USP19 expression in a reporter activity using a functional half-estrogen response element (hERE) from Usp19. Daidzein inhibited E2-induced recruitment of ERα and promoted recruitment of ERß to the Usp19 hERE. Dietary daidzein down-regulated the expression of USP19 at the mRNA and protein levels and increased soleus muscle mass in female mice, but not in males. In soleus muscle from ovariectomized (OVX) female mice, dietary daidzein inhibited E2-increased USP19 mRNA expression and E2-decreased muscle mass. Furthermore, E2 induced the recruitment of ERα and ERß to the hERE, whereas daidzein inhibited E2-induced recruitment of ERα, and enhanced E2-increased recruitment of ERß, to the Usp19 hERE. These results demonstrate that dietary daidzein decreases USP19 mRNA expression through ERß and increases soleus muscle mass in young female mice, but not in male mice, under physiological conditions.