The surfaces of lipid droplets (LDs) constitute major sites of regulated accumulation and degradation of lipid in cells, and hence play important roles in lipid homeostasis of the whole body. CGI-58 (also called α/β hydrolase domain-containing protein 5 (ABHD5)) is a member of the α/β-hydrolase family of proteins and is a product of the causal gene of Chanarin–Dorfman syndrome (CDS), which is characterized by excessive storage of triacylglycerol (TG) in various tissues. CGI-58 is distributed predominantly on the surface of LDs and plays a crucial role in TG degradation in cells. In the process of lipolysis, CGI-58 coordinates with several proteins, including perilipin, a member of the PAT family of proteins, and adipose triglyceride lipase (ATGL), a putative rate-limiting enzyme for TG degradation in adipocytes. Besides its role in adipocytes, CGI-58 is involved in lipid degradation in various tissues, including those of skin and liver. This review focuses on the functions and protein interactions of CGI-58 on the surface of LDs in the regulation of fat mobilization in cells.
Fat specific protein 27 (FSP27) was originally isolated by screen for genes specifically expressed in fully differentiated mouse adipocytes. FSP27 and cell death-inducing DFF45-like effector C (CIDEC), the human homologue of FSP27, belong to the CIDE family. The FSP27 in adipocytes was recently reported to be a lipid droplet (LD)-associated protein, that promotes the formation of unilocular LDs. An FSP27 knockout mouse demonstrated lean phenotypes with atrophic adipose tissue as a result of high-energy expenditure; this mouse line was also resistant to diet-induced obesity and insulin resistance. Interestingly, FSP27 was also expressed in the steatoic liver of a type II diabetes model mouse. The expression of FSP27 was markedly decreased in livers lacking the nuclear receptor peroxisome proliferator-activated receptor γ. Forced expression of FSP27 in hepatocytes in vitro or in vivo led to an increase of LD through increased triglyceride levels. The current status of the physiological roles of FSP27/CIDEC in adipose tissue and liver are discussed along with its significance as a factor involved in the development of metabolic disorders.
The liver is not a storage site of excess energy as triacylglycerides but a major site of carbohydrate storage, playing a vital role in glucose homeostasis, and the hepatic lipid droplets (LDs) should have a distinct physiologic role from those in lipid-storing tissues. Most studies so far have been limited to characterization of the LDs in cultured cells or of the liver of animals maintained on a normal laboratory diet, and little is known about the properties of the LDs in the liver responding to dietary excess, irregular fats, and potentially toxic compounds contained in a natural food diet. We started to characterize the hepatic LDs in wild-type and peroxisome proliferator-activated receptor α (PPARα)-null mice fed various natural diets by identifying the liver-enriched LD-associated proteins and the changes in lipid compositions. Based on the currently available data, we propose the hypothesis that hepatic LDs play vital protective roles against diet-derived excess fatty acids and potentially toxic hydrophobic compounds by temporarily storing them as neutral lipids or compounds until completion of the remodeling of fatty acids and detoxification of the compounds in a PPARα-dependent manner.
Lipid droplets (LDs) are cellular lipid storage organelles involved not only in lipid homeostasis but also in a variety of diseases. Chronic hepatitis C virus (HCV) infection affects host lipid metabolism, and thus induces LD accumulation in the liver. Recent studies have suggested that cellular LDs also play a crucial role in the HCV life cycle. Interactions between HCV proteins, especially the core protein, and LDs are required for the morphogenesis of infectious HCV. The present minireview will summarize the recent research progress about this unique relationship between LDs and the HCV life cycle.
Oilseeds accumulate a large amount of storage lipids, which are used as sources of carbon and energy for seed germination and seedling growth. The storage lipids are accumulated in oil bodies during seed maturation. Oil bodies in seeds are surrounded with three oil-body-membrane protein families, oleosins, caleosins and steroleosins. These proteins are plant-specific and much abundant in seeds. Here we show a unique function of oleosins in preventing fusion of oil bodies and maintaining seed germination. Reverse genetic analysis using oleosin-deficient mutants shows the inverse proportion of oil-body sizes to total oleosin contents. The double mutant ole1 ole2 with the lowest levels of oleosins has irregularly-enlarged oil bodies throughout the seed cells, and hardly germinates. Germination rates are positively associated with oleosin contents, suggesting that the defects of germination are related to the expansion of oil bodies due to oleosin deficiency. Interestingly, freezing treatment followed by imbibition at 4 °C inhibits seed germination of single mutants (ole1 and ole2), which germinate normally without freezing treatment. The freezing treatment accelerates the fusion of oil bodies and generates eccentric nuclei in ole1 seeds, which caused seed mortality. Taken together, our findings suggest that oleosins increase the viability of oilseeds by preventing abnormal fusion of oil bodies for overwintering. Knowledge of oleosin contributes a great deal to not only an insight into freezing tolerance of oilseeds, but also creating genetically modified plants for developing a bioenergy and biomass resource.
Ascorbic acid (AA) has a strong anti-oxidant function evident as its ability to scavenge superoxide radicals in vitro. Moreover, AA is an essential ingredient for post-translational proline hydroxylation of collagen molecules. Dehydroascorbic acid (DHA), the oxidized form of AA, is generated from these reactions. In this study, we describe an improved method for assessing DHA in biological samples. The use of 35 mM tris(2-carboxyethyl)phosphine hydrochloride (TCEP) as a reductant completely reduced DHA to AA after 2 h on ice in a 5% solution of metaphosphoric acid containing 1 mM ethylenediaminetetraacetic acid (EDTA) at pH 1.5. This method enabled us to measure the DHA content in multiple tissues and plasma of 6-weeks-old mice. The percentages of DHA per total AA differed markedly among these tissues, i.e., from 0.8 to 19.5%. The lung, heart, spleen and plasma had the highest levels at more than 10% of DHA per total AA content, whereas the cerebrum, cerebellum, liver, kidney and small intestine had less than 5% of DHA per total AA content. This difference in DHA content may indicate an important disparity of oxidative stress levels among physiologic sites. Therefore, this improved method provides a useful standard for all DHA determinations.
In the present study, we examined levels of oxidative stress in the serum, brain and kidneys of normotensive Wistar Kyoto rats (WKY) and stroke prone spontaneously hypertensive rats (SHRSP) at 10 weeks of age. Levels of advanced oxidation protein products (AOPP), oxidized albumin and oxidized proteins, markers of oxidative stress, were significantly decreased in serum among SHRSP as compared with WKY. Levels of oxidized proteins determined by immunoblotting were significantly increased in the brain, but not kidney, of SHRSP. The mRNA level of super oxide dismutase (SOD) determined by real time polymerase chain reaction (PCR) and the protein level of catalase assessed by immunoblotting were significantly increased in the brain of SHRSP. From these results, it was suggested that levels of oxidative stress were higher in the brain than serum or kidneys of SHRSP at 10 weeks of age, but are not caused by decreases in the expression of SOD and catalase.
Multivalent interactions are frequently used to enhance ligand-receptor binding affinity. In this study, mono-, di- and trimeric Ala-Val-Thr-Gly-Arg-Gly-Asp-Ser-Tyr (AVTGRGDSY) peptides, labeled with 125I or Cy5.5, were compared in vitro and in vivo. Using human embryonic kidney HEK293 (naturally αV-positive and β3-negative), HEK293(β1) (β1-transfected and αVβ3-negative), HEK293(β3) (β3-transfected and strongly αVβ3-positive), and human glioblastoma U87MG (naturally αVβ3-positive) cell lines we evaluated their binding affinity and specificity. In vitro, the monomeric AVTGRGDSY showed specific binding to both HEK293(β1) and HEK293(β3) cells. Multimerization resulted in no change toward HEK293 cells, diminished binding with HEK293(β1) cells, but substantially enhanced binding with αVβ3-positive HEK293(β3) and U87MG cells. Moreover, multimeric AVTGRGDSY peptides were found to be nearly comparable to the same molar concentration of a well-known αVβ3-specific cyclo(RGDfV) (c(RGDfV)) peptide in specificity and affinity for targeting αVβ3 integrin. Non-invasive in vivo optical imaging demonstrated that as compared to its monomeric analogue, the Cy5.5-labeled dimeric AVTGRGDSY peptide produced markedly enhanced tumor-to-background contrast in HEK293(β3) tumor-bearing mice than in HEK293(β1) tumor-bearing mice. In conclusion, the present study showed the difference of monomeric and multimeric linear Arg-Gly-Asp (RGD)-containing compound in integrin selectivity and affinity. Our data provide useful information for the design of novel RGD peptides.
Dihydropyrazine (DHP), which is produced during the Maillard reaction, generates radicals that not only cause breakage of chromosomal DNA leading to mutagenic lesions but also induce oxidative damage to cellular proteins. In the present study, we show that three DHP derivatives, which generated superoxide anions, caused inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). SH-compounds, such as cysteine, dithiothreitol (DTT), 2-mercaptoethanol, 2-mercaptoethylamine, and N-acetyl-cysteine, suppressed the inhibition of GAPDH by DHP in vitro, although the effect of DHP on GAPDH was not reversed by DTT. In addition, DHP-exposed Escherichia coli showed almost unaffected growth on plates containing a rich medium, but poor growth on plates containing M9 synthetic medium with glucose as the sole carbon source. Furthermore, DHP-exposed E. coli exhibited reduced GAPDH activity. These findings indicate that DHP disturbs the glycolytic pathway by inhibiting GAPDH activity.
Anoectochilus formosanus HAYATA, commonly known as “Jewel Orchids,” which has been used as Chinese folk medicines, is being subjected to a huge crisis, whose wild resources have gradually become more and more scarce. Hence, micropropagation protocol by axillary branching established for A. formosanus was employed for large-scale commercial production. In this study, due to the somaclonal variation and on the basis of some virtue of intersimple sequence repeats (ISSR) analysis, we firstly utilized the ISSR primers to investigate the genetic stability of A. formosanus propagated in vitro for a period of more than 5 years. Among the total 100 bands amplified by 17 ISSR markers, 77 bands were distributed in size from 500 bp to 1.5 kbp, while only 5 bands were beyond 1.8 kbp in size. Meanwhile, according to the cluster analysis, genetic similarity was more than 94% and the polymorphism rate was only 2.76% among the total 1810 scorable bands. All results demonstrate A. formosanus, multiplied by axillary branching, maintained high genetic fidelity even after a period of more than 5 years under in vitro propagation with only a low risk of genetic instability. The results from this study provide an important basis for giving evidence of genetic stability of A. formosanus before micropropagation for large-scale commercial production.
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates a spectrum of toxic and biological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and related compounds. Several reports have shown that the AhR plays an important role in the control of cell-cycle progression, and this function is thought to be partly associated with the tumor promotion activity of dioxin. However, the underling mechanisms are not fully understood. We have previously shown that overexpression of AhR, as well as AhR ligand treatment, stimulates cell proliferation of human lung cancer A549 cells. In AhR-activated cells, the expression levels of DNA synthesis-related genes such as proliferating cell nuclear antigen (PCNA) and RFC38 are notably increased. Expression of these genes is mainly regulated by E2F1, a transcription factor that is crucial for transition of the cell cycle from G1 to S phase. We show here that the transcriptional activity of E2F1 is increased by the AhR agonist treatment and that this effect depends on the presence of AhR. Functional mapping of AhR showed that the Per-Arnt-Sim (PAS) B domain is required for promotion of E2F1 activity. The mechanism involves formation of a complex of AhR and E2F1 on the regulatory region in the E2F1 target gene, followed by recruitment of coactivator activator for thyroid hormone and retinoid receptors (ACTR). Consequently, the results in this study indicate the physiological function of AhR as a potent transcriptional coactivator of E2F1-dependent transcription and implicate the AhR-E2F1 interaction as a part of the mechanism by which AhR/Arnt promotes cell proliferation.
Pro-drugs of non-steroidal anti-inflammatory drugs (NSAIDs), such as loxoprofen are widely used for clinical purposes because they are not so harmful to the gastrointestinal mucosa. We recently showed that NSAIDs such as indomethacin and celecoxib have direct cytotoxicity (ability to induce necrosis and apoptosis in gastric mucosal cells) due to their membrane permeabilizing activities, which is involved in NSAID-induced gastric lesions. We show here that under conditions where indomethacin and celecoxib clearly induce necrosis and apoptosis, loxoprofen and its active metabolite loxoprofen-OH, do not have such effects in primary culture of guinea pig gastric mucosal cells. Loxoprofen and loxoprofen-OH induced apoptosis more effectively in cultured human gastric cancer cells than in the primary culture. Loxoprofen and loxoprofen-OH exhibited much lower membrane permeabilizing activities than did indomethacin and celecoxib. We thus consider that the low direct cytotoxicity of loxoprofen observed in vitro is involved in its relative safety on production of gastric lesions in clinical situation.
To elucidate molecular mechanisms of adipocyte differentiation, we previously isolated TC10-like/TC10βLong (TCL/TC10βL), regulators of G protein signaling 2 (RGS2), factor for adipocyte differentiation (fad) 104 and fad158, which were transiently expressed in the early phase of adipogenesis. These four genes seem to be positive regulators of adipogenesis, since their knockdown resulted in the inhibition of adipocyte differentiation. When growth-arrested 3T3-L1 cells were induced to differentiate, they first reentered the cell cycle and underwent several rounds of cell division, a process known as mitotic clonal expansion (MCE). Although MCE is required for completion of the differentiation program, its molecular mechanisms are not fully understood. We examined the roles of these four genes during MCE. Knockdown of the expression of TCL/TC10βL impaired MCE, while that of RGS2 or fad104 had a rather weak effect and that of fad158 had no effect. The suppression of TCL/TC10βL inhibited the incorporation of bromodeoxyuridine (BrdU), indicating that DNA synthesis was prevented by the knockdown. Interestingly, the knockdown of TCL/TC10βL inhibited the expression of the CCAAT/enhancer-binding protein (C/EBP) family, C/EBPβ and C/EBPδ, during MCE. The results strongly suggest that TCL/TC10βL regulates adipocyte differentiation by controlling MCE and this regulatory effect is closely linked to C/EBPβ and C/EBPδ expression.
To clarify the exact anti-arthritic action mechanisms of chondroitin sulfate (CS), we evaluated the effects of CS derived from shark cartilage (CS-SC) composed mainly of chondroitin-6-sulfate and porcine trachea cartilage (CS-PC) composed mostly of chondrotin-4-sulfate on the functions of human articular chondrocytes and synovial fibroblasts. Both CS-SC and CS-PC (from 1 to 100 μg/ml) effectively suppressed the interleukin (IL)-1β (10 ng/ml)-enhanced gene expression of aggrecanase-1/a disintegrin and metalloproteinase with thrombospondin-like motifs (ADAMTS)-4 and aggrecanase-2/ADAMTS-5 in articular chondrocytes embedded in alginate beads and synovial fibroblasts. In addition, CS-SC and CS-PC overcame the IL-1β-mediated suppression of the aggrecan core protein mRNA, and suppressed the IL-1β-enhanced collagenase-3/matrix metalloproteinase (MMP)-13 gene expression in chondrocytes. CS-PC, but not CS-SC effectively recovered the IL-1β-reduced gene expression of tissue inhibitor of metalloproteinases (TIMP)-3 in chondrocytes, and enhanced the production of TIMP-1 in synovial fibroblasts. It is noteworthy that CS is able to modulate the function of synovial fibroblasts as well as that of chondrocytes. Therefore, CS is very likely to be multifunctional chondroprotective material for degenerative arthritic diseases.
Apocynum venetum LINN. is an important Chinese crude drug, and its sibling species A. pictum SCHRENK is a confusable herb which is similar to it. The purpose of this study is to develop DNA molecular markers to distinguish A. venetum from A. pictum through the combinative technologies of bulked segregate analysis (BSA) and randomly amplified polymorphic DNA (RAPD). Two putative markers B08-407 and B03-1368 specific for A. venetum were identified and sequenced. Based on the sequence information, two pairs of primers were designed and synthesized for sequence characterized amplified region (SCAR) markers. But only one primer pair, B03-1368, produced a clear SCAR band in all samples of A. venetum and not in A. pictum. This SCAR marker was found useful for rapid identification of A. venetum from A. pictum.
Although anticancer effect of gambogic acid (GA) and its potential mechanisms were well documented in past decades, limited information is available on the anticancer effect of gambogenic acid (GNA), another major active component of Gamboge. Here we performed a study to determine whether GNA possesses anticancer effect and find its potential mechanisms. The results suggested that GNA significantly inhibited the proliferation of several tumor cell lines in vitro and in vivo. Treatment with GNA dose and time dependently induced A549 cells apoptosis, arrested the cells to G0/G1 phase in vitro and down-regulated the expression of cyclin D1 and cyclooxygenase (COX)-2 in mRNA level. In addition, anticancer effect was further demonstrated by applying xenografts in nude mice coupled with the characteristic of apoptosis in the GNA treated group. Taken together, these observations might suggest that GNA inhibits tumor cell proliferation via apoptosis-induction and cell cycle arrest.
The anti-aging effects of cyanidin were investigated under stress-induced premature senescence (SIPS) using WI-38 human diploid fibroblasts. WI-38 cells that were treated with 300 μM H2O2 showed losses of cell viability, increased lipid peroxidation, and shortened cell lifespans. However, treatment with cyanidin attenuated cellular oxidative stress through increase of cell viability and the inhibition of lipid peroxidation. In addition, the life spans of young-, middle-, and old-aged WI-38 cells were prolonged by cyanidin treatment. Furthermore, H2O2-treated WI-38 cells significantly increased mRNA and protein expressions of nuclear factor-κB, cyclooxygenase-2, and inducible nitric oxide synthase, while those treated with cyanidin had significantly decreased expressions. These results suggest that cyanidin may delay the aging process by attenuating oxidative stress under the SIPS cellular model.
The present study was performed to evaluate the antihypertensive effects of honokiol in vivo in spontaneously hypertensive rats (SHR). The effects of honokiol were investigated by determination of the blood pressure, vascular reactivity, oxidative parameters, and histologic change in the aorta. Long-term administration of honokiol (400 mg/kg/d) to SHR decreased systolic blood pressure significantly. Honokiol (200, 400 mg/kg/d) enhanced the aortic relaxation in response to acetylcholine after 49-d treatment, but had no significant effects on the relaxation to sodium nitroprusside. The oral administration of honokiol significantly increased the plasma level of NO2−/NO3−, but decreased the level of malondialdehyde in liver of SHR compared with the control vehicle. In addition, SHR administered honokiol showed significant reductions in the elastin bands and media thickness in the aorta. These results suggest that chronic treatment with honokiol exerts an antihypertensive effect in SHR, and its vasorelaxant action and antioxidant properties may contribute to reducing the elevated blood pressure.
A tetramethylpyrazine analogue, CXC195, was synthesized by the Boekelheide reaction, in which the second methyl group of tetramethylpyrazine (TMP) was replaced with (4,4′-fluorine) diphenyl-methyl-1-piperazidine, the active group of flunarizine. We have observed protective effects of CXC195 on vascular endothelial cell survival under oxidative stress in previous study. The aim of the present study was to investigate the effects of CXC195 against apoptosis induced by hydrogen peroxide in human umbilical vein endothelial cells (HUVECs). Accordingly, a biochemical approach to elucidate the apoptotic signal pathways was attempted. HUVECs were exposed to 150 μM H2O2 for 12 h, resulting in an increase of apoptotic cells assessed by the nuclear staining assay and flow cytometry. Mitochondrial membrane potential was detected by retention of rhodamine123. The concentration of free intracellular calcium was determined by fura-2/AM fluorometry. Co-incubation with CXC195 reduced the percentage of apoptotic cells and inhibited the loss of mitochondrial membrane potential and intracellular calcium overload induced by H2O2. Induction of p53, the activation of caspase-3 by H2O2 which accompanying downregulation of bcl-2, was blocked by CXC195. In addition, CXC195 clearly improved phosphorylation levels of the antiapoptotic extracellular signal-regulated kinase-1/2 (ERK1/2) in cells undergoing oxidative damage. Moreover, CXC195 showed stronger effects on inhibition of apoptotic cells and loss of mitochondrial membrane potential and activation of phosphorylated ERK1/2 than TMP. These results suggest that CXC195 prevents reactive oxygen species-induced apoptosis through inhibition of the mitochondria-dependent caspase-3 pathway and ERK pathway to show a better beneficial effect in protecting endothelial cells than TMP.
To clarify the interaction between hippocampal γ-aminobutyric acid (GABA)A receptor and N-methyl-D-aspartate (NMDA) receptor in the retention of spatial working memory, the effects of muscimol, (+)MK-801, cyclosporin A and combined use of these drugs were studied on the retention of spatial working memory in a delayed spatial win-shift (SWSh) task. Intrahippocampal injection of muscimol at a dose of 3 nmol/side caused a significant decrease in the number of correct choices and an increase in the number of across-phase errors. On the other hand, (+)MK-801 showed no significant effect on the number of correct choices, across-phase errors and within-phase errors, even at a dose of 1.5 nmol/side; however, (+)MK-801 1.5 nmol/side significantly potentiated the effect of muscimol observed at a dose of 3 nmol/side on the number of correct choices and across-phase errors. Cyclosporin A at a dose of 3 nmol/side, which showed no effect when used separately, significantly potentiated the effect of muscimol observed at a dose of 3 nmol/side. These results indicate that hippocampal NMDA receptors regulate the effect of spatial working memory induced by muscimol. In addition, calcineurin may be involved in muscimol-induced impairment of memory retention.
Diabetes impairs the expression and function of endogenous growth factors, leading to increased cardiovascular events in diabetic patients. Supplementation of fibroblast growth factors (FGFs) protected the heart from ischemia/reperfusion (I/R)-induced injury in animal models. However, it has not yet been tested in diabetic heart. The present study was thus to clarify whether basic fibroblast growth factor (bFGF) could protect the heart from I/R-induced damage under diabetic conditions using a rat model. Male Sprague Dawley rats were used to induce diabetes by intraperitoneal injection of streptozotocin. Eight weeks later, I/R injury was generated in diabetic rats and age-matched non-diabetic rats. All I/R rats were administrated bFGF or saline through intramyocardial injection. Seven days after I/R, cardiac infarction, structural changes, cell death and blood vessel density, serum malondialdehyde (MDA) and cardiac enzyme lactate dehydrogenase (LDH) were examined. We found that I/R induced significant increases in the cardiac infarction, blood MDA contents and LDH activities, and the expression of caspase-3. Treatment of I/R rats with bFGF simultaneously with reperfusion significantly attenuated I/R-induced pathological changes, along with a significant increase in the cardiac blood vessel density in both diabetic and non-diabetic rates. The protective effects of bFGF on I/R-induced cardiac injury in diabetic group are less than those in non-diabetic group. The results indicated that bFGF provide a protection of the heart against I/R-induced oxidative damage, cell death and infarction under diabetic conditions.
Platycodon grandiflorum (PG) (Korean name, Doraji; Chinese name, Jiegeng; and Japanese name, Kikyo) is a perennial plant in the Campanulaceae family that contains triterpenoid saponins, carbohydrates, and fibers. This study was carried out to investigate effects of root of PG on fatty liver inhibition in high fat diet (HFD)-fed C57BL/6 mice. C57BL/6 mice were divided into control, total extract of PG (T-PG, 500 mg/kg) and saponin fraction (S-PG, 50 mg/kg)-treated groups. Significant decreases in body weight, associated with fat mass reduction, were observed in PG-treated groups (p<0.05). Hepatic lipid content and score index calculated from morphometric observations on fatty liver were significantly decreased in the PG-treated groups (p<0.05). Moreover, activities of fatty acid synthase (FAS) and carnitine palmitoyl-transferase (CPT) were significantly suppressed and increased as compared with the control group, respectively (p<0.05). mRNA expressions of the sterol regulatory element binding protein (SREBP1c) and stearoyl-CoA desaturase (SCD1) gene were suppressed in the T-PG and S-PG groups (p<0.05). From these findings, we speculate that fatty liver inhibition effects of PG extract and its saponins appear to be conferred by hepatic lipogenesis and acceleration of energy expenditure, along with modulation of liver FAS and CPT activities in HFD-fed C57BL/6 mice.
Despite the health risks for postmenopausal women, the indications and ideal candidates for hormone replacement therapy remain unclear. The present study used ovariectomized rats to examine the safety and effects of the Chinese herbal formula Menoprogen (MPG), which is prescribed for menopausal syndrome. Daily oral MPG (1000 mg/kg body weight) for 2 weeks significantly recovered uterine and adrenal gland atrophy and restored serum estradiol, estrone and progesterone levels that were decreased in rats by bilateral ovariectomy. However, yeast two-hybrid and nuclear receptor cofactor assays showed that MPG did not bind estrogen receptors α (ERα) and β, and immunohistochemical staining revealed that unlike 17β-estradiol, MPG did not stimulate the protein expression of ERα, progesterone receptor, c-jun and c-fos in the uterus. No side effects of MPG were confirmed in vivo. These findings suggest that MPG would be useful for treating women with premenopausal and postmenopausal syndromes.
Neuroinflammation has recently been implicated as an important mechanism responsible for the progression of neurodegenerative diseases. Activated microglia produce various proinflammatory cytokines and nitric oxide (NO) that are toxic to neurons. Thus, inhibition of microglial activation may alleviate neuroinflammatory and neurodegenerative processes. Among several fluorovinyloxyacetamide derivatives that were screened by microglia cell-based assay, a novel synthetic compound KT-15073 was identified to strongly attenuate the microglial production of NO and tumor necrosis factor-α (TNF-α). This compound also suppressed the gene expression of interleukin-1β, inducible nitric oxide synthase, and TNF-α. KT-15073 inhibited the nuclear translocation and DNA binding of nuclear factor-κB as well as phosphorylation of p38 mitogen-activated protein kinase. In addition, KT-15073 reduced the cytotoxicity of lipopolysaccharide (LPS)-stimulated microglia toward B35 neuroblastoma cells in the microglia/neuroblastoma coculture, suggesting that the compound might exhibit the neuroprotective activity. Thus, KT-15073 has an anti-inflammatory activity in microglia, and may have a therapeutic potential for the treatment of neuroinflammatory or neurodegenerative diseases.
It has been reported that red ginseng acidic polysaccharide (RGAP), isolated from Korean red ginseng, displays immunostimulatory and anti-tumor activities. In a follow-up study, we have carried out a study on the anti-hyperlipidemic effects of RGAP using hyperlipidemic rats acutely induced by Triton WR1339 or corn oil intravenously injected. Oral administration of RGAP (100 to 1000 mg/kg) dose-dependently reduced the serum levels of triglyceride (TG) up-regulated by Triton WR1339, an inducer of endogenous model hyperlipidemia. Moreover, RGAP treatment was shown to significantly decrease the levels of non-esterified fatty acid (NEFA) concomitant with TG reduction. However, such reduction effects were not observed in cases of total cholesterol (TC) and phospholipid levels increased under the same conditions, although there was an inhibitory tendency. Similar suppressive patterns were also seen in hepatic parameters (total lipids and TG) under the same conditions. The exogenous hyperlipidemic rat condition triggered by corn oil also supported the anti-hyperlipidemic activity of RGAP in serum and hepatic parameters of TG and NEFA. Interestingly, RGAP significantly enhanced the serum activity of lipoprotein lipase, a key hydrolytic enzyme of lipid molecules in lipoprotein, in a dose-dependent manner up to 80%, implying potential involvement of this enzyme in lowering TG and NEFA by RGAP. Therefore, our data suggest that RGAP may play an additional role in reducing hyperlipidemic conditions, which can be used as a valuable neutraceutical application for the treatment of hyperlipidemia.
Aminopiperidine derivatives, Compound 1a and 1b, are novel small molecules that inhibit C-14 reduction catalyzed by Erg24p in ergosterol synthesis of Candida albicans. We evaluated the properties of the in vitro and in vivo activities of these compounds against pathogenic fungi and compared their activities with those of fluconazole. Compound 1a and 1b exhibited potent in vitro activities against clinically important fungi such as Candida species, including both of fluconazole-resistant strains of C. albicans and non-albicans Candida, Aspergillus fumigatus, and Cryptococcus neoformans. Against C. albicans, its mode of action was fungistatic. Furthermore, orally administered Compound 1b clearly prolonged the survival of infected mice in systemic lethal infection caused by C. albicans. These results suggest that aminopiperidine derivative is a promising lead compound for an orally available novel antifungal drug with a broad spectrum.
Experimental autoimmune myocarditis (EAM)-induced heart failure in rats is used to study the pathogenesis of heart failure. Based on a proteomic analysis of soluble (S) and membranous (M) fractions extracted from ventricles of rats with a stable chronic form of EAM-induced heart failure, we assessed changes in protein levels and their correlation to heart functions to gain insights into the pathogenesis and to explore new targets for the treatment of heart failure. Proteins were separated by two-dimensional gel electrophoresis and silver stained spots were analyzed. In the S-fraction, 274±3 spots were detected in the normal (N)-group and 273±6 in the heart failure (HF)-group. In the HF-group, 26 of the spots were increased and 15 were decreased in intensity. In the M-fraction, 277±3 spots were detected in the N-group and 277±2 in the HF-group, with 20 spots increased and 10 decreased in intensity. We analyzed relationships between the expression of these proteins and 11 parameters of heart function, and found all the significantly changed spots to correlate with at least one of the parameters. We analyzed 49 spots that correlated with over 9 parameters of heart function using mass spectrometry, and identified 15 as proteins with increased expression including glucose regulated protein (GRP)78, an endoplasmic-stress related protein, and heat shock protein (HSP)90β, a molecular chaperone, and 4 spots as proteins with decreased expression. It is suggested that in the heart failure model, GRP78 and HSP90β play a role in the protection or deterioration of the heart and may be new targets for treatment.
Honokiol, a neolignan, is a physiologically active component of kouboku (Magnolia obovata), a herb used in traditional Chinese medicine. This study investigated the effects of honokiol on the differentiation and function of osteoclasts induced by receptor activator of nuclear factor-κB ligand (RANKL). Honokiol markedly inhibited RANKL-induced tartrate-resistant acid phosphatase (TRAP) activity and the formation of TRAP-positive multinucleated cells in both bone marrow-derived monocytes and RAW264 cells. In experiments to elucidate its mechanism of action, honokiol was found to suppress RANKL-induced phosphorylation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK). The RANKL-induced expressions of c-Fos and nuclear factor of activated T cells-c1 (NFATc1), which are crucial transcriptional factors for osteoclastogenesis, were also reduced by treatment with honokiol. Furthermore, honokiol induced disruption of the actin rings in mature osteoclasts (mOCs) without affecting the cell viability and suppressed osteoclastic pit formation on dentin slices. Taken together, these results suggest that honokiol inhibits osteoclast differentiation by suppressing the activation of MAPKs (p38 MAPK, ERK and JNK), decreasing the expressions of c-Fos and NFATc1, and attenuates bone resorption by disrupting the actin rings in mOCs. Therefore, honokiol could prove useful for the treatment of bone diseases associated with excessive bone resorption.
Treatment of primary cultured cortical cells with erythro-9-(2-hydroxy-3-nonyl) adenine hydrochloride (EHNA), an inhibitor of adenosine deaminase (ADAR), for 6 d significantly and concentration-dependently reduced the editing efficacy at sites C and D but not at site A or B of 5-HT2CR mRNA. The treatment failed to affect the editing of ADAR-2 pre-mRNA and a subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)-type glutamate receptor (GluR2) mRNA. These findings suggest that EHNA is useful for clarifying the functional roles of 5-HT2CR mRNA editing at sites C and D.
The leaves of three Ligularia species belonging to the family Compositae, Ligularia stenocephala, L. fischeri, and L. fischeri var. spiciformis, were qualitatively and quantitatively analyzed on the caffeoylquinic acids by HPLC and subjected to peroxynitrite-scavenging assay. The IC50 of the MeOH extract of L. stenocephala was 1.62±0.03 μg/ml and the major caffeoylquinic acids of L. stenocephala were 5-O-caffeoylquinic acid, 3,5-di-O-caffeoyl-muco-quinic acid, and 3,5-di-O-caffeoylquinic acid. The compositions of caffeoylquinic acids were different for the three plants. Since percentage of total caffeoylquinic acids of the extract was highest (42.20% of the MeOH extract and 94.52% of the BuOH extract) in L. stenocephala and potent in peroxynitrite-scavenging assay, the extracts of L. stenocephala were chosen to perform in vivo anti-ulcerogenic activity. Treatment of mice with the MeOH- and BuOH extracts decreased the diameter of gastric lesions caused by HCl/ethanol- and indomethacin/bethanechol and decreased the volume of gastric juice, suggesting that caffeoylquinic acids have anti-ulcerogenic activity. These results suggest that the leaves of Ligularia species may help prevent or treat gastric ulcers.
The physiological function of organic anion transporter OAT2 (SLC22A7) remains unclear, but since OAT2 transports purine derivatives, it may be involved in renal handling of uric acid, the final metabolite of purine derivatives. In the present study, we studied uric acid transport in stably OAT2-expressing HEK293 cells (HEK293/OAT2). OAT2 mediated uptake, but not efflux, of [14C]uric acid. Uric acid transport was saturable with Km of 1168±335 μM (mean and S.E.M.) and Vmax of 2.57±0.350 nmol/min/mg protein. The [14C]uric acid uptake was sensitive to Cl− and was enhanced at acidic pH. In cis-inhibition assay, [14C]uric acid uptake was inhibited by several mono- or dicarboxylic acids, but it was not trans-stimulated by any of the compounds tested. The pattern of inhibition of OAT2-mediated uric acid transport by various drugs was different from that of OAT1- or OAT3-mediated transport. Furthermore, OAT2-mediated transport of uric acid was inhibited by an antiuricosuric drug, pyrazinecarboxylic acid. These results revealed distinct characteristics of uric acid transport via OAT2 compared with other uric acid transporters, suggesting that OAT2 plays a role in renal uric acid uptake from blood as a first step of tubular secretion. OAT2 may therefore be a potential target for regulating serum uric acid level.
The aim of this study was to reveal the expression and function of P-glycoprotein and multidrug resistance-associated proteins (MRP), members of the ATP-binding cassette (ABC) superfamily of drug transporters, in cultured human Y79 retinoblastoma cells. ABC transporter mRNA expression was evaluated by conventional reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR analyses. Cellular accumulation of rhodamine 123 (P-glycoprotein substrate), calcein (MRP substrate), and doxorubicin (P-glycoprotein/MRP substrate) was analyzed by fluorometry. Conventional RT-PCR analysis showed the expression of multidrug resistance 1 (MDR1), MRP1, MRP2 and lung resistance-related protein (LRP) mRNAs. Real-time RT-PCR analysis revealed that the expression levels of the MDR1 and MRP2 genes in Y79 cells were much lower than those in human intestinal cell line Caco-2, while the expression level of MRP1 was higher than that in Caco-2 cells. The accumulation of rhodamine 123 was not enhanced by verapamil or reversin 205, inhibitors of P-glycoprotein, indicating no function of P-glycoprotein in Y79 cells. The accumulation of calcein was significantly increased by various MRP inhibitors including probenecid, indicating that MRP functions in Y79 cells. The accumulation of doxorubicin was increased in the presence of metabolic inhibitors (10 mM 2-deoxyglucose and 5 mM sodium azide). However, most MRP inhibitors such as probenecid and indomethacin did not affect doxorubicin accumulation, while cyclosporin A and taclorimus significantly increased doxorubicin accumulation. These results suggest that MRP, but not P-glycoprotein, functions in Y79 cells, and that the efflux of doxorubicin from Y79 cells may be due to an ATP-dependent transporter, which has not been identified yet.
The purpose of our study was to develop a formulation of liposomal salbutamol sulfate (SBS) dry powder inhaler (DPI) for the treatment of asthma. Liposomes of high encapsulation efficiency (more than 80%) were prepared by a vesicular phospholipid gel (VPG) technique. SBS VPG liposomes were subjected to lyophilization using different kinds of cryoprotectants in various mass ratios. Coarse lactose (63—106 μm) in different mass ratios was used as a carrier. Magnesium stearate (0.5%) was added as a lubricator. The dry liposomal powders were then crushed by ball milling and sieved through a 400-mesh sieve to control the mean particle size at about 10 μm. The effects of different kinds of cryoprotectants and the amount of lactose carrier on the fine particle fraction (FPF) of SBS were investigated. The results showed that the developed formulation of liposomal dry powder inhaler was obtained using lactose as a cryoprotectant with a mass ratio of lyophilized powder to carrier lactose at 1 : 5; 0.5% magnesium stearate was used as a lubricator. The value of FPF for SBS was 41.51±2.22% for this formulation. Sustained release of SBS from the VPG liposomes was found in the in vitro release study. The study results offer the promising possibility of localized pulmonary liposomal SBS delivery in the anhydrous state.
Plasminogen activator inhibitor-1 (PAI-1), the primary physiological inhibitor of plasminogen activators, is an important contributor to hypofibrinolysis in the presence of metabolic disorders such as diabetes and obesity. The C57BLKS/J (BKS) inbred mouse strain is a popular animal model of type 2 diabetes. We previously described that food deprivation (FD) induces adipose PAI-1 expression in both lean BKS mice and BKS-db/db mice carrying a mutation in the leptin receptor gene. To evaluate the effects of the background of mouse strains, we examined FD-induced PAI-1 expression in the liver, heart and epididymal adipose tissues of BKS, C57BL/6J (B6), C3H/HeN and ICR mice. We found that PAI-1 expression is significantly induced in the heart and liver of fasted mice, although levels of expression in adipose tissues are strain-dependent. The effect of FD on plasma PAI-1 levels is also strain-dependent. Genetic background seems to be an important factor that should be considered when investigating thrombosis and fibrinolysis relative to metabolic changes in mice.
During the fall of 2009, a trace of unauthorized genetically modified (GM) flax (Linum usitatissimum L.) line, CDC Triffid, which is resistant to sulfonylurea herbicides, was detected in many countries including Japan. A method to reliably identify the CDC Triffid line was urgently required. We developed a novel construct-specific real-time polymerase chain reaction (PCR) method to identify the mutant acetolactate synthase gene in the CDC Triffid line. We confirmed that the method can detect 0.001% GM flax in DNA mixing solution. The study shows that the developed method is specific, sensitive and reliable way to monitor a trace of CDC Triffid.