Cinnamon extract improves abnormalities in glucose tolerance by decreasing Acyl-CoA synthetase long-chain family 1 expression in adipocytes.

We previously demonstrated that cinnamon extract (CE) alleviates streptozotocin-induced type 1 diabetes in rats. The present study aimed to elucidate the detailed molecular target of cinnamon in cultured adipocytes and epididymal adipose tissue of type 2 diabetes model mice. Two-dimensional gel electrophoresis was employed to determine the molecular target of cinnamon in adipocytes. The function of Acyl-CoA synthetase long-chain family-1 (ACSL1), a molecular target of cinnamon that was identified in this study, was further investigated in 3T3-L1 adipocytes using specific inhibitors. Type 2 diabetes model mice (KK-Ay/TaJcl) were used to investigate the effect of CE on glucose tolerance, ACSL1 expression, and related signal molecules in vivo. CE decreased ACSL1 mRNA and protein expression in 3T3-L1 adipocytes but increased glucose uptake and AMPK signaling activation; moreover, a similar effect was observed with an ACSL1 inhibitor. CE improved glucose tolerance and downregulated ACSL1 in mice adipose tissue in vivo. ACSL1 was demonstrated as a molecular target of CE in type 2 diabetes both in a cell culture system and diabetic mouse model.

The garlic-derived organosulfur compound diallyl trisulphide suppresses tissue factor function.

Tissue factor (TF) is a critical initiator of extrinsic coagulation that sometimes causes thromboembolism. Diallyl trisulphide (DATS) is a secondary metabolite of allicin generated in crushed garlic, with various pharmacological effects. This study aimed to clarify the effect of DATS on the extrinsic coagulation elicited by TF and arteriosclerosis. TF activity was measured using a clotting assay in TF-expressing HL60 cells. DATS inhibited TF activity in a dose-dependent manner. TF expression in TNF-α-stimulated human umbilical vein endothelial cells was examined using real-time PCR and western blotting. DATS inhibited TF mRNA and protein expression induced by TNF-α via inhibition of JNK signalling. The effect of DATS on arteriosclerosis was also examined in apolipoprotein E-deficient mice. DATS administration in these mice tended to decrease atherosclerotic lesion size. These results strongly suggest that DATS prevents thromboembolism triggered by atherosclerosis via the inhibition of plaque formation and TF function.

Diallyl Trisulfide Prevents Obesity and Decreases miRNA-335 Expression in Adipose Tissue in a Diet-Induced Obesity Rat Model.

SCOPE: Diallyl trisulfide (DATS), an organosulfur compound generates in crushed garlic, has various beneficial health effects. A growing body of evidence indicates that miRNAs are involved in the pathology of lifestyle diseases including obesity. The anti-obesogenic effect of garlic is previously reported; however, the effects of DATS on obesity, and the relationship between garlic compounds and the involvement of miRNA remains unclear. Here, the anti-obesogenic activity of DATS and the potential role of miRNA in a diet-induced obesity rat model are investigated. METHODS AND RESULTS: Oral administration of DATS suppressed body and white adipose tissue (WAT) weight gain in rats fed a high-fat diet compared with vehicle-administered rats. DATS lowered the plasma and liver triglyceride levels in obese rats, and decreased lipogenic mRNA levels including those of Srebp1c, Fasn, and Scd1 in the liver. DATS also suppressed de novo lipogenesis in the liver. Transcriptomic analyses of miRNA and mRNA in the epididymal WAT of obese rats using microarrays revealed that DATS decreased miRNA-335 expression and normalized the obesity-related mRNA transcriptomic signatures in epididymal WAT. CONCLUSION: The potent anti-obesogenic effects of DATS and its possible mechanism of action was clearly demonstrated in this study.

Macrophage potentiates the recovery of liver zonation and metabolic function after acute liver injury.

The liver is an exclusive organ with tremendous regenerative capacity. Liver metabolic functions exhibit spatial heterogeneity, reflecting liver zonation. The mechanisms controlling the proliferation of hepatocytes and the accompanying matrix reconstruction during regeneration have been well explored, but the recovery potential of differentiated metabolic functions and zonation after liver injury remains unclear. We employed a mouse model of carbon tetrachloride (CCl4) induced-acute liver injury with clodronate-induced macrophage depletion to clarify the impact of liver injury on liver metabolism and recovery dynamics of metabolic function and liver zonation during regeneration. Depleting macrophages suppressed tissue remodelling and partially delayed cell proliferation during regeneration after liver injury. In addition, recovery of metabolic functions was delayed by suppressing the tissue remodelling caused by the depleted macrophages. The model revealed that drug metabolic function was resilient against the dysfunction caused by liver injury, but glutamine synthesis was not. Metabolomic analysis revealed that liver branched-chain amino acid (BCAA) and carbohydrate metabolism were suppressed by injury. The plasma BCAA concentration reflected recovery of hepatic function during regeneration. Our study reveals one aspect of the regenerative machinery for hepatic metabolism following acute liver injury.

The role of increased FGF21 in VLDL-TAG secretion and thermogenic gene expression in mice under protein malnutrition.

Protein malnutrition promotes hepatic lipid accumulation in growing animals. In these animals, fibroblast growth factor 21 (FGF21) rapidly increases in the liver and circulation and plays a protective role in hepatic lipid accumulation. To investigate the mechanism by which FGF21 protects against liver lipid accumulation under protein malnutrition, we determined whether upregulated FGF21 promotes the thermogenesis or secretion of very-low-density lipoprotein (VLDL)-triacylglycerol (TAG). The results showed that protein malnutrition decreased VLDL-TAG secretion, but the upregulation of FGF21 did not oppose this effect. In addition, protein malnutrition increased expression of the thermogenic gene uncoupling protein 1 in inguinal white adipose and brown adipose tissue in an FGF21-dependent manner. However, surgically removing inguinal white adipose tissue did not affect liver triglyceride levels in protein-malnourished mice. These data suggest that FGF21 stimulates thermogenesis under protein malnutrition, but this is not the causative factor underlying the protective role of FGF21 against liver lipid accumulation.

Fish oil suppresses obesity more potently in lean mice than in diet-induced obese mice but ameliorates steatosis in such obese mice.

This study sought to clarify the antiobesity effects of fish oil (FO) in terms of prevention and amelioration. An isocaloric diet composed of lard or FO was given to lean C57BL/6J mice for the study of prevention and high-fat diet-induced obese (DIO) mice for the study of amelioration for 4 weeks. Body weight gain and food efficiency were potently suppressed by FO in lean mice compared to lard diet-fed mice. Uncoupling protein-1 (UCP-1) expression in inguinal white adipose tissue (WAT) was also significantly induced by FO in lean mice. FO also suppressed body weight gain and food efficiency in DIO mice but did not reduce body weight. FO ameliorated liver steatosis in DIO mice by mildly inducing UCP-1 in inguinal WAT. FO suppressed obesity more potently in lean mice than in DIO mice but ameliorated steatosis in the DIO mice.

Acute supplementation with an amino acid mixture suppressed the exercise-induced cortisol response in recreationally active healthy volunteers: a randomized, double-blinded, placebo-controlled crossover study.

BACKGROUND: Few studies have demonstrated the suppressive effects of amino acids (AAs) on the level of cortisol during exercise in humans. We hypothesized that an AA mixture containing arginine, which promotes lipid metabolism, valine, which effectively decreases the level of glucocorticoid, and serine, a substrate in the production of phosphatidylserine that is reported to blunt increases in cortisol, would suppress the exercise-induced cortisol response by combining the positive effects of the AAs synergistically. METHODS: A randomized, double-blinded, placebo-controlled crossover trial was conducted. Twenty healthy recreationally active males ingested either an AA mixture containing 1.8 g of arginine, 1.1 g of valine, and 0.1 g of serine or a placebo. Thirty minutes after ingestion, subjects performed an exercise trial on a cycle ergometer for 80 min at 50% maximal oxygen consumption. Plasma cortisol and other blood parameters immediately before and after the exercise were evaluated. RESULTS: Plasma cortisol concentrations after exercise were significantly higher than those before exercise in the placebo condition (9.51 ± 0.85 vs 14.39 ± 2.15, p < 0.05), while there was no significant difference in the AA condition (9.71 ± 0.93 vs 9.99 ± 1.23, p = 0.846). In addition, the increase in plasma cortisol before and after exercise was significantly lower in the AA condition than in the placebo condition (0.28 [- 2.75, 3.31] vs 4.87 [0.89, 8.86], p < 0.05). For the level of adrenocorticotropin, there was a significant difference between before and after exercise only in the placebo condition (24.21 ± 2.91 vs 53.17 ± 6.97, p < 0.01) but not in the AA condition (27.33 ± 3.60 vs 46.92 ± 10.41, p = 0.057). Blood glucose, plasma lactate, plasma ammonia, serum creatine phosphokinase, serum total ketone body, and serum free fatty acid were also significantly changed by the exercise load in both conditions, but no significant differences were observed between the two conditions. CONCLUSIONS: The present study demonstrated that the AA mixture suppressed the cortisol response during exercise without affecting exercise-related biological parameters such as glucose or lipid metabolism. TRIAL REGISTRATION: UMIN Clinical Trials Registry, UMIN000023587 . Registered 19 August 2016.

Garlic oil suppresses high-fat diet induced obesity in rats through the upregulation of UCP-1 and the enhancement of energy expenditure.

Garlic (Allium sativum L.) has long been used as a medicinal food. Indeed, garlic and its constituents have been shown to possess potent regulatory activities in bodily functions, including blood coagulation, lipid metabolism, immunity and xenobiotic metabolism. In this study, we aimed to examine the anti-obesity effects of garlic oil and to elucidate the possible underlying mechanisms. For this purpose, garlic oil (GO; 80 mg/kg body weight, p.o.) or corn oil alone as a vehicle-control were administered to male Sprague-Dawley rats every other day for 10 weeks. The results revealed that GO administration significantly reduced body weight gain and white adipose tissue (WAT) mass, which had been increased by feeding on the AIN-76-based high-fat diet (60% kcal fat). Expired gas analysis was performed at 9 weeks following the GO administration to calculate fuel oxidation. GO administration enhanced O2 consumption during the dark period (at night) and increased energy expenditure through fat oxidation during the light period (daytime); however, carbohydrate oxidation remained unaltered. Western blot analysis revealed that GO administration increased UCP1 protein expression in brown adipose tissue (BAT). On the whole, the findings of this study indicated that GO suppressed body weight gain and WAT mass in the rat model of high-fat diet-induced obesity by increasing UCP1 expression and by enhancing fat oxidation and energy expenditure.

Diallyl Trisulfide Inhibits Platelet Aggregation through the Modification of Sulfhydryl Groups.

Diallyl trisulfide (DATS) is a secondary metabolite of allicin, a volatile organosulfur flavoring compound generated by the crushing of garlic. These compounds have various medicinal effects such as antiplatelet activity. In this study, we demonstrated for the first time the cellular mechanism involved in the inhibition of platelet aggregation by DATS and dipropyl trisulfide (DPTS), which is a saturated analogue of DATS. Washed murine platelets were incubated with these sulfides, and platelet aggregation was evaluated by light transmission aggregometry. The amount of reaction products produced by DATS, DPTS, and glutathione (GSH) was measured using liquid chromatography-mass spectrometry. Compared with DPTS, DATS potently inhibited platelet aggregation induced by thrombin, U46619, and collagen. N-Ethylmaleimide (NEM), which is commonly used to modify sulfhydryl groups, also suppressed platelet aggregation. The reactivity of DATS with GSH was higher than that of DPTS. These data suggested that DATS inhibited platelet aggregation through the reaction of sulfhydryl groups.

Diallyl Trisulfide Enhances Benzo[a]pyrene-induced CYP1A1 Expression and Metabolic Activation in Hepatic HepG2 Cells.

BACKGROUND/AIM: Benzo[a]pyrene (BaP), an environmental pollutant produced by combustion processes, induces expression of cytochrome P450 (CYP) 1A1 via the activation of aryl hydrocarbon receptor (AHR). Induced CYP1A1 is involved in BaP metabolism, resulting in either detoxification or metabolic activation in a context-dependent manner. The effect of diallyl trisulfide (DATS), a garlic-derived organosulfur compound, on BaP metabolism has not been investigated. MATERIALS AND METHODS: The combined effect of DATS and BaP on BaP metabolism in hepatocyte-derived HepG2 cells was examined. RESULTS: DATS enhanced BaP-induced CYP1A1 and CYP1B1 mRNA expression, BaP hydroxylation and BaP-DNA adduct formation. Combined treatment of BaP and DATS also increased reactive oxygen species levels. DATS enhanced BaP-induced AHR recruitment and histone H3 acetylation on the CYP1A1 promoter. CONCLUSION: DATS combined treatment enhances BaP metabolic activation through an AHR-modulating mechanism.

A designed cell-penetrating human SOCS2 protein suppresses GH-dependent cancer cell proliferation.

Suppressor of cytokine signaling (SOCS) 2, a negative regulator of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), which is associated with acromegaly and cancers, is a promising candidate molecule for treating various diseases. To facilitate its use in protein therapy, we designed and constructed a human SOCS2 protein containing a membrane-permeable peptide sequence and expressed it in an Escherichia coli system. The partially purified recombinant protein was effectively delivered into several cancer cell lines and inhibited cell growth. Biochemical analysis showed that the recombinant SOCS2 protein interacted with growth hormone receptor (GHR) and downregulated GH-STAT5 signaling target genes. Our results suggest that the designed cell-penetrating SOCS2 protein will be useful in intercellular protein therapy to cure cancers. Abbreviations: SOCS: suppressor of cytokine signaling; GH: growth hormone; GHR: growth hormone receptor; IGF-1: insulin-like growth factor 1; CP: cell-penetrating; STAT: signal transducer and activator of transcription; JAK: Janus kinase; HNF: hepatocyte nuclear factor; MTM: membrane-translocating motif; HIV: human immunodeficiency virus.

Effects of pharmacological inhibition of plasminogen binding on liver regeneration in rats.

The fibrinolysis system is thought to play an important role in liver regeneration. We previously found that plasminogen (Plg) is localized to the cell surface of regenerating liver tissue as well as proliferating hepatocytes in vitro. Here, we investigated the significance of Plg binding to the cell surface during liver regeneration. Pre-administration of tranexamic acid (TXA), which is a competitive inhibitor of Plg binding, to hepatectomized rats mildly delayed restoration of liver weight in vivo. Although binding of Plg to the cell membrane decreased following TXA administration, TXA showed little effect on hepatocyte proliferation in rats. We also discovered that Plg treatment did not stimulate proliferation of primary rat hepatocytes in vitro. These results suggest that Plg/plasmin potentiates liver regeneration via a pathway distinct from those through which hepatocyte proliferation is stimulated.

Prevention of Cardiovascular Diseases by Garlic-Derived Sulfur Compounds.

Lifestyle-related diseases have complex pathogenesis which consists of several different steps. Basic causes of the diseases are attributed to unhealthy lifestyles in dietary habits, physical activity and suffering stress. The unhealthy lifestyles induce risk factors such as hypertension, dyslipidemia, obesity, and hyperglycemia. These risk factors all promote arteriosclerosis leading to serious vascular complications (i.e., thrombotic diseases), myocardial infarction and cerebral infarction. The total number of deaths from these thrombotic diseases almost equals that from cancer in our country. Cancer is also a typical lifestyle-related disease. Food has three different functions: the primary function is to provide enough nutrients to meet the metabolic requirements. The secondary function is the one relating to food preference. The third function is to control our body functions, which help reduction of the risk of diseases. Some of the compounds derived from food, especially phytochemicals in edible plants, vegetables and herbs, have potent functions to control our body functions and contribute to promoting our health. In this review article, we overview the lifestyle-related diseases and food functions involving prevention and amelioration of the diseases by food components especially from edible plants and vegetables. As an example, we will describe the food function of garlic and the prevention of lifestyle-related diseases by its components. Allyl sulfides are characteristic flavor compounds derived from garlic, and these organosulfur compounds are responsible for the food function of garlic.

Identification of molecular target of diallyl trisulfide in leukemic cells.

To identify the molecular target of diallyl trisulfide (DATS) in human leukemic cell line U937, we examined modification of thiol group(s) of cellular proteins by the redox 2D PAGE. A unique protein spot appeared by DATS treatment was identified to be heat shock protein 27 (HSP27). Hsp27 is suggested to be one of the molecular target of DATS in U937.

Diallyl trisulfide induces apoptosis in Jurkat cells by the modification of cysteine residues in thioredoxin.

We reported the regulation of protein function by oxidative modification of the specific cysteine residue(s) by diallyl trisulfide (DATS). In this study, we examined if DATS modifies the cysteine residue of thioredoxin (Trx) by urea-polyacryl amide gel electrophoresis. DATS modified two specific cysteine residues in Trx and this oxidative modification of cysteine residues would be sole causative of the apoptosis induced by DATS in leukemic cells.

Bovine milk-derived α-lactalbumin inhibits colon inflammation and carcinogenesis in azoxymethane and dextran sodium sulfate-treated mice.

Cyclooxygenase-2 is expressed early in colon carcinogenesis and plays crucial role in the progress of the disease. Recently, we found that α-lactalbumin had anti-inflammatory activity by inhibiting cyclooxygenase-2. In experiment 1, we investigated the effects of α-lactalbumin on the colon carcinogenesis initiated with azoxymethane (AOM) followed by promotion with dextran sodium sulfate (DSS) in mice. Dietary treatment with α-lactalbumin decreased fecal occult blood score at 3 days after DSS intake. α-Lactalbumin also decreased the colon tumor at week 9. In experiment 2, AOM-treated mice were sacrificed at 7 days after DSS intake. The plasma and colon prostaglandin E2 (PGE2) levels in AOM/DSS-treated mice were higher than those in the DSS-treated mice without initiation by AOM. α-Lactalbumin decreased PGE2 in both plasma and colon. These results suggest that α-lactalbumin effectively inhibited colon carcinogenesis, and the inhibition may be due to the decreased PGE2 by inhibiting cyclooxygenase-2 at cancer promotion stages.

Sulphur-containing compounds of durian activate the thermogenesis-inducing receptors TRPA1 and TRPV1.

Durian (Durio zibethinus Murr.) is classified as a body-warming food in Indian herbalism, and its hyperthermic effect is empirically known in Southeast Asia. To investigate the mechanism underlying this effect, we focused on the thermogenesis-inducing receptors, TRPA1 and TRPV1. Durian contains sulphides similar to the TRPA1 and TRPV1 agonists of garlic. Accordingly, we hypothesized that the thermogenic effect of durian is driven by sulphide-induced TRP channel activation. To investigate our hypothesis, we measured the TRPA1 and TRPV1 activity of the sulphur-containing components of durian and quantified their content in durian pulp. These sulphur-containing components had a stronger effect on TRPA1 than TRPV1. Furthermore, sulphide content in the durian pulp was sufficient to evoke TRP channel activation and the main agonist was diethyl disulphide. From these results, we consider that the body-warming effect of durian is elicited by TRPA1 activation with its sulphides, as can be seen in spices.

Cinnamon extract enhances glucose uptake in 3T3-L1 adipocytes and C2C12 myocytes by inducing LKB1-AMP-activated protein kinase signaling.

We previously demonstrated that cinnamon extract (CE) ameliorates type 1 diabetes induced by streptozotocin in rats through the up-regulation of glucose transporter 4 (GLUT4) translocation in both muscle and adipose tissues. This present study was aimed at clarifying the detailed mechanism(s) with which CE increases the glucose uptake in vivo and in cell culture systems using 3T3-L1 adipocytes and C2C12 myotubes in vitro. Specific inhibitors of key enzymes in insulin signaling and AMP-activated protein kinase (AMPK) signaling pathways, as well as small interference RNA, were used to examine the role of these kinases in the CE-induced glucose uptake. The results showed that CE stimulated the phosphorylation of AMPK and acetyl-CoA carboxylase. An AMPK inhibitor and LKB1 siRNA blocked the CE-induced glucose uptake. We also found for the first time that insulin suppressed AMPK activation in the adipocyte. To investigate the effect of CE on type 2 diabetes in vivo, we further performed oral glucose tolerance tests and insulin tolerance tests in type 2 diabetes model rats administered with CE. The CE improved glucose tolerance in oral glucose tolerance tests, but not insulin sensitivity in insulin tolerance test. In summary, these results indicate that CE ameliorates type 2 diabetes by inducing GLUT4 translocation via the AMPK signaling pathway. We also found insulin antagonistically regulates the activation of AMPK.

Role of p16(INK4a) in the inhibition of DNA synthesis stimulated by HGF or EGF in primary cultured rat hepatocytes.

In the present study, we investigated the role of p16(INK4a) in the inhibition of DNA synthesis stimulated by hepatocyte growth factor (HGF) or epidermal growth factor (EGF) using RNA interference in primary cultured rat hepatocytes. The transfection of small interfering RNAs targeting p16(INK4a) reduced the corresponding mRNA and protein expression by more than approximately 90% and 50%, respectively, at 24 h after transfection. In the cells transfected with p16(INK4a) small interfering RNA, control, HGF, and EGF-stimulated DNA synthesis as assessed by (3)H-thymidine incorporation increased by approximately 1.5-fold, 1.6-fold, and 1.7-fold, respectively, compared with that in the control small interfering RNA-transfected cells. These findings indicate that p16(INK4a) plays a significant role in the inhibition of DNA synthesis.