A plasma 3-marker microRNA biosignature distinguishes spinal tuberculosis from other spinal destructive diseases and pulmonary tuberculosis.

Accurate spinal tuberculosis (TB) diagnosis is of utmost importance for adequately treating and managing the disease. Given the need for additional diagnostic tools, this study aimed to investigate the utility of host serum miRNA biomarkers for diagnosing and distinguishing spinal tuberculosis (STB) from pulmonary tuberculosis (PTB) and other spinal diseases of different origins (SDD). For a case-controlled investigation, a total of 423 subjects were voluntarily recruited, with 157 cases of STB, 83 cases of SDD, 30 cases of active PTB, and 153 cases of healthy controls (CONT) in 4 clinical centers. To discover the STB-specific miRNA biosignature, a high-throughput miRNA profiling study was performed in the pilot study with 12 cases of STB and 8 cases of CONT using the Exiqon miRNA PCR array platform. A bioinformatics study identified that the 3-plasma miRNA combination (hsa-miR-506-3p, hsa-miR-543, hsa-miR-195-5p) might serve as a candidate biomarker for STB. The subsequent training study developed the diagnostic model using multivariate logistic regression in training data sets, including CONT(n=100) and STB (n=100). Youden's J index determined the optimal classification threshold. Receiver Operating Characteristic (ROC) curve analysis showed that 3-plasma miRNA biomarker signatures have an area under the curve (AUC) = 0.87, sensitivity = 80.5%, and specificity = 80.0%. To explore the possible potential to distinguish spinal TB from PDB and other SDD, the diagnostic model with the same classification threshold was applied to the analysis of the independent validation data set, including CONT(n=45), STB(n=45), brucellosis spondylitis (BS, n=30), PTB (n=30), spinal tumor (ST, n=30) and pyogenic spondylitis (PS, n=23). The results showed diagnostic model based on three miRNA signatures could discriminate the STB from other SDD groups with sensitivity=80%, specificity=96%, Positive Predictive Value (PPV)=84%, Negative Predictive Value (NPV)=94%, the total accuracy rate of 92%. These results indicate that this 3-plasma miRNA biomarker signature could effectively discriminate the STB from other spinal destructive diseases and pulmonary tuberculosis. The present study shows that the diagnostic model based on 3-plasma miRNA biomarker signature (hsa-miR-506-3p, hsa-miR-543, hsa-miR-195-5p) may be used for medical guidance to discriminate the STB from other spinal destructive disease and pulmonary tuberculosis.

Mycobacterium tuberculosis Induced Osteoblast Dysregulation Involved in Bone Destruction in Spinal Tuberculosis.

Disturbance of bone homeostasis caused by Mycobacterium tuberculosis (Mtb) is a key clinical manifestation in spinal tuberculosis (TB). However, the complete mechanism of this process has not been established, and an effective treatment target does not exist. Increasing evidence shows that abnormal osteoclastogenesis triggered by an imbalance of the receptor activator of NF-κB ligand (RANKL)/osteoprotegerin (OPG) axis may play a key role in the disturbance of bone homeostasis. Previous studies reported that RANKL is strongly activated in patients with spinal TB; however, the OPG levels in these patients were not investigated in previous studies. In this study, we investigated the OPG levels in patients with spinal TB and the dysregulation of osteoblasts caused by Mtb infection. Inhibition of the Mce4a gene of Mtb by an antisense locked nucleic acid (LNA) gapmer (Mce4a-ASO) was also investigated. Analysis of the serum OPG levels in clinical samples showed that the OPG levels were significantly decreased in patients with spinal TB compared to those in the group of non-TB patients. The internalization of Mtb in osteoblasts, the known major source of OPG, was investigated using the green fluorescent protein (GFP)-labeled Mycobacterium strain H37Ra (H37RaGFP). The cell-associated fluorescence measurements showed that Mtb can efficiently enter osteoblast cells. In addition, Mtb infection caused a dose-dependent increase of the CD40 mRNA expression and cytokine (interleukin 6, IL-6) secretion in osteoblast cells. Ligation of CD40 by soluble CD154 reversed the increased secretion of IL-6. This means that the induced CD40 is functional. Considering that the interaction between CD154-expressing T lymphocytes and bone-forming osteoblast cells plays a pivotal role in bone homeostasis, the CD40 molecule might be a strong candidate for mediating the target for treatment of bone destruction in spinal TB. Additionally, we also found that Mce4a-ASO could dose-dependently inhibit the Mce4a gene of Mtb and reverse the decreased secretion of IL-6 and the impaired secretion of OPG caused by Mtb infection of osteoblast cells. Taken together, the current finding provides breakthrough ideas for the development of therapeutic agents for spinal TB.

Activation of Sigma Receptors With Afobazole Modulates Microglial, but Not Neuronal, Apoptotic Gene Expression in Response to Long-Term Ischemia Exposure.

Stroke continues to be a leading cause of death and serious long-term disability. The lack of therapeutic options for treating stroke at delayed time points (≥6 h post-stroke) remains a challenge. The sigma receptor agonist, afobazole, an anxiolytic used clinically in Russia, has been shown to reduce neuronal and glial cell injury following ischemia and acidosis; both of which have been shown to play important roles following an ischemic stroke. However, the mechanism(s) responsible for this cytoprotection remain unknown. Experiments were carried out on isolated microglia from neonatal rats and cortical neurons from embryonic rats to gain further insight into these mechanisms. Prolonged exposure to in vitro ischemia resulted in microglial cell death, which was associated with increased expression of the pro-apoptotic protein, Bax, the death protease, caspase-3, and reduced expression in the anti-apoptotic protein Bcl-2. Incubation of cells with afobazole during ischemia decreased the number of microglia expressing both Bax and caspase-3, and increased cells expressing Bcl-2, which resulted in a concomitant enhancement in cell survival. In similar experiments, incubation of neurons under in vitro ischemic conditions resulted in higher expression of Bax and caspase-3, while at the same time expression of Bcl-2 was decreased. However, unlike observations made in microglial cells, afobazole was unable to modulate the expression of these apoptotic proteins, but a reduction in neuronal death was still noted. The functional state of surviving neurons was assessed by measuring metabolic activity, resting membrane potential, and responses to membrane depolarizations. Results showed that these neurons maintained membrane potential but had low metabolic activity and were unresponsive to membrane depolarizations. However, while these neurons were not fully functional, there was significant protection by afobazole against long-term ischemia-induced cell death. Thus, the effects of sigma receptor activation on microglial and neuronal responses to ischemia differ significantly.

BDE-47 and BDE-85 stimulate insulin secretion in INS-1 832/13 pancreatic ß-cells through the thyroid receptor and Akt.

PBDEs (polybrominated diphenyl ethers) are environmental pollutants that have been linked to the development of type 2 diabetes, however, the precise mechanisms are not clear. Particularly, their direct effect on insulin secretion is unknown. In this study, we show that two PBDE congeners, BDE-47 and BDE-85, potentiate glucose-stimulated insulin secretion (GSIS) in INS-1 832/13 cells. This effect of BDE-47 and BDE-85 on GSIS was dependent on thyroid receptor (TR). Both BDE-47 and BDE-85 (10µM) activated Akt during an acute exposure. The activation of Akt by BDE-47 and BDE-85 plays a role in their potentiation of GSIS, as pharmacological inhibition of PI3K, an upstream activator of Akt, significantly lowers GSIS compared to compounds alone. This study shows that BDE-47 and BDE-85 directly act on pancreatic ß-cells to stimulate GSIS, and that this effect is mediated by the thyroid receptor (TR) and Akt activation.

Thymoquinone ameliorates diabetic phenotype in Diet-Induced Obesity mice via activation of SIRT-1-dependent pathways.

Thymoquinone, a natural occurring quinone and the main bioactive component of plant Nigella sativa, undergoes intracellular redox cycling and re-oxidizes NADH to NAD+. TQ administration (20 mg/kg/bw/day) to the Diet-Induced Obesity (DIO) mice reduced their diabetic phenotype by decreasing fasting blood glucose and fasting insulin levels, and improved glucose tolerance and insulin sensitivity as evaluated by oral glucose and insulin tolerance tests (OGTT and ITT). Furthermore, TQ decreased serum cholesterol levels and liver triglycerides, increased protein expression of phosphorylated Akt, decreased serum levels of inflammatory markers resistin and MCP-1, and decreased NADH/NAD+ ratio. These changes were paralleled by an increase in phosphorylated SIRT-1 and AMPKα in liver and phosphorylated SIRT-1 in skeletal muscle. TQ also increased insulin sensitivity in insulin-resistant HepG2 cells via a SIRT-1-dependent mechanism. These findings are consistent with the TQ-dependent re-oxidation of NADH to NAD+, which stimulates glucose and fatty acid oxidation and activation of SIRT-1-dependent pathways. Taken together, these results demonstrate that TQ ameliorates the diabetic phenotype in the DIO mouse model of type 2 diabetes.

The Detrimental Role Played by Lipocalin-2 in Alcoholic Fatty Liver in Mice.

We have previously shown that the ethanol-mediated elevation of lipocaline-2 (LCN2) is closely associated with the development of alcoholic fatty liver disease (AFLD) in mice. Herein, we aimed to understand the functional significance of LCN2 induction by ethanol and to explore its underlying mechanisms. We evaluated the effects of LCN2 in an in vitro cellular alcoholic steatosis model and in an animal study using wild-type and LCN2 knockout mice fed for 4 weeks with an ethanol-supplemented Lieber-DeCarli diet. In the cellular model of alcoholic steatosis, recombinant LCN2 or overexpression of LCN2 exacerbated ethanol-induced fat accumulation, whereas knocking down LCN2 prevented steatosis in hepatocytes exposed to ethanol. Consistently, removal of LCN2 partially but significantly alleviated alcoholic fatty liver injury in mice. Mechanistically, LCN2 mediates detrimental effects of ethanol in the liver via disrupted multiple signaling pathways, including aberrant nicotinamide phosphoribosyltransferase-sirtuin 1 axis, perturbed endocrine metabolic regulatory fibroblast growth factor 15/19 signaling, and impaired chaperone-mediated autophagy. Finally, compared with healthy human livers, liver samples from patients with AFLD had lower gene expression of several LCN2-regualted molecules. Our study demonstrated a pivotal and causal role of LCN2 in the development of AFLD and suggested that targeting the LCN2 could be of great value for the treatment of human AFLD.

miR-217 regulates ethanol-induced hepatic inflammation by disrupting sirtuin 1-lipin-1 signaling.

Ethanol-mediated injury, combined with gut-derived lipopolysaccharide (LPS), provokes generation of proinflammatory cytokines in Kupffer cells, causing hepatic inflammation. Among the mediators of these effects, miR-217 aggravates ethanol-induced steatosis in hepatocytes. However, the role of miR-217 in ethanol-induced liver inflammation process is unknown. Here, we examined the role of miR-217 in the responses to ethanol, LPS, or a combination of ethanol and LPS in RAW 264.7 macrophages and in primary Kupffer cells. In macrophages, ethanol substantially exacerbated LPS-mediated induction of miR-217 and production of proinflammatory cytokines compared with LPS or ethanol alone. Consistently, ethanol administration to mice led to increases in miR-217 abundance and increased production of inflammatory cytokines in isolated primary Kupffer cells exposed to the combination of ethanol and LPS. miR-217 promoted combined ethanol and LPS-mediated inhibition of sirtuin 1 expression and activity in macrophages. Moreover, miR-217-mediated sirtuin 1 inhibition was accompanied by increased activities of two vital inflammatory regulators, NF-κB and the nuclear factor of activated T cells c4. Finally, adenovirus-mediated overexpression of miR-217 led to steatosis and inflammation in mice. These findings suggest that miR-217 is a pivotal regulator involved in ethanol-induced hepatic inflammation. Strategies to inhibit hepatic miR-217 could be a viable approach in attenuating alcoholic hepatitis.

L-serine supplementation attenuates alcoholic fatty liver by enhancing homocysteine metabolism in mice and rats.

BACKGROUND: Hyperhomocysteinemia plays an important role in the development of hepatic steatosis, and studies indicate that homocysteine-lowering treatment inhibits the development of fatty liver. OBJECTIVE: We evaluated the effects of L-serine on alcoholic fatty liver and homocysteine metabolism. METHODS: In a binge ethanol study, male C57BL/6 mice were divided into 4 groups: control, ethanol + vehicle, and ethanol + 20 or 200 mg/kg L-serine. Mice were gavaged with ethanol (5 g/kg body weight) 3 times every 12 h with or without L-serine which was given twice 30 min before the last 2 ethanol doses. Control mice were fed isocaloric dextran-maltose. In a chronic ethanol study, male Wistar rats were divided into 3 groups: control, ethanol, and ethanol + L-serine. Rats were fed a standard Lieber-DeCarli ethanol diet (36% ethanol-derived calories) for 4 wk with or without dietary L-serine supplementation (1%; wt:vol) for the last 2 wk. In control rats, the ethanol-derived calories were replaced with dextran-maltose. The effects of L-serine were also tested in AML12 cells manipulated to have high homocysteine concentrations by silencing the genes involved in homocysteine metabolism. RESULTS: Binge ethanol treatment increased serum homocysteine and hepatic triglyceride (TG) concentrations by >5-fold vs. controls, which were attenuated in the 200-mg/kg L-serine treatment group by 60.0% and 47.5%, respectively, compared with the ethanol group. In the chronic ethanol study, L-serine also decreased hepatic neutral lipid accumulation by 63.3% compared with the ethanol group. L-serine increased glutathione and S-adenosylmethionine by 94.0% and 30.6%, respectively, compared with the ethanol group. Silencing betaine homocysteine methyltransferase, cystathionine ß-synthase, or methionine increased intracellular homocysteine and TG concentrations by >2-fold, which was reversed by L-serine when L-serine-independent betaine homocysteine methyltransferase was knocked down. CONCLUSION: These results demonstrate that L-serine ameliorates alcoholic fatty liver by accelerating L-serine-dependent homocysteine metabolism.

LXR-α antagonist meso-dihydroguaiaretic acid attenuates high-fat diet-induced nonalcoholic fatty liver.

Collaborative regulation of liver X receptor (LXR) and sterol regulatory element binding protein (SREBP)-1 are main determinants in hepatic steatosis, as shown in both animal models and human patients. Recent studies indicate that selective intervention of overly functional LXRα in the liver shows promise in treatment of fatty liver disease. In the present study, we evaluated the effects of meso-dihydroguaiaretic acid (MDGA) on LXRα activation and its ability to attenuate fatty liver in mice. MDGA inhibited activation of the LXRα ligand-binding domain by competitively binding to the pocket for agonist T0901317 and decreased the luciferase activity in LXRE-tk-Luc-transfected cells. MDGA significantly attenuated hepatic neutral lipid accumulation in T0901317- and high fat diet (HFD)-induced fatty liver. The effect of MDGA was so potent that treatment with 1mg/kg for 2 weeks completely reversed the lipid accumulation induced by HFD feeding. MDGA reduced the expression of LXRα co-activator protein RIP140 and LXRα target gene products associated with lipogenesis in HFD-fed mice. These results demonstrate that MDGA has the potential to attenuate nonalcoholic steatosis mediated by selective inhibition of LXRα in the liver in mice.

Deletion of SIRT1 from hepatocytes in mice disrupts lipin-1 signaling and aggravates alcoholic fatty liver.

BACKGROUND & AIMS: Sirtuin (SIRT1) is a nicotinamide adenine dinucleotide-dependent protein deacetylase that regulates hepatic lipid metabolism by modifying histones and transcription factors. Ethanol exposure disrupts SIRT1 activity and contributes to alcoholic liver disease in rodents, but the exact pathogenic mechanism is not clear. We compared mice with liver-specific deletion of Sirt1 (Sirt1LKO) mice with their LOX littermates (controls). METHODS: We induced alcoholic liver injury in male Sirt1LKO and control mice, placing them on Lieber-DeCarli ethanol-containing diets for 10 days and then administering a single dose of ethanol (5 g/kg body weight) via gavage. Liver and serum samples were collected. We also measured messenger RNA levels of SIRT1, SFRS10, and lipin-1ß and lipin-1α in liver samples from patients with alcoholic hepatitis and individuals without alcoholic hepatitis (controls). RESULTS: On the ethanol-containing diet, livers of Sirt1LKO mice accumulated larger amounts of hepatic lipid and expressed higher levels of inflammatory cytokines than control mice; serum of Sirt1LKO mice had increased levels of alanine aminotransferase and aspartate aminotransferase. Hepatic deletion of SIRT1 exacerbated ethanol-mediated defects in lipid metabolism, mainly by altering the function of lipin-1, a transcriptional regulator of lipid metabolism. In cultured mouse AML-12 hepatocytes, transgenic expression of SIRT1 prevented fat accumulation in response to ethanol exposure, largely by reversing the aberrations in lipin-1 signaling induced by ethanol. Liver samples from patients with alcoholic hepatitis had reduced levels of SIRT1 and a higher ratio of Lpin1ß/α messenger RNAs than controls. CONCLUSIONS: In mice, hepatic deletion of Sirt1 promotes steatosis, inflammation, and fibrosis in response to ethanol challenge. Ethanol-mediated impairment of hepatic SIRT1 signaling via lipin-1 contributes to development of alcoholic steatosis and inflammation. Reagents designed to increase SIRT1 regulation of lipin-1 can be developed to treat patients with alcoholic fatty liver disease.

Hepatic-specific lipin-1 deficiency exacerbates experimental alcohol-induced steatohepatitis in mice.

UNLABELLED: Lipin-1 regulates lipid metabolism by way of its function as an enzyme in the triglyceride synthesis pathway and as a transcriptional coregulatory protein and is highly up-regulated in alcoholic fatty liver disease. In the present study, using a liver-specific lipin-1-deficient (lipin-1LKO) mouse model, we aimed to investigate the functional role of lipin-1 in the development of alcoholic steatohepatitis and explore the underlying mechanisms. Alcoholic liver injury was achieved by pair feeding wild-type and lipin-1LKO mice with modified Lieber-DeCarli ethanol-containing low-fat diets for 4 weeks. Surprisingly, chronically ethanol-fed lipin-1LKO mice showed markedly greater hepatic triglyceride and cholesterol accumulation, and augmented elevation of serum liver enzymes accompanied by increased hepatic proinflammatory cytokine expression. Our studies further revealed that hepatic removal of lipin-1 in mice augmented ethanol-induced impairment of hepatic fatty acid oxidation and lipoprotein production, likely by way of deactivation of peroxisome proliferator-activated receptor γ coactivator-1 alpha, a prominent transcriptional regulator of lipid metabolism. CONCLUSIONS: Liver-specific lipin-1 deficiency in mice exacerbates the development and progression of experimental alcohol-induced steatohepatitis. Pharmacological or nutritional modulation of hepatic lipin-1 may be beneficial for the prevention or treatment of human alcoholic fatty liver disease.

Ethanol administration exacerbates the abnormalities in hepatic lipid oxidation in genetically obese mice.

Alcohol consumption synergistically increases the risk and severity of liver damage in obese patients. To gain insight into cellular or molecular mechanisms underlying the development of fatty liver caused by ethanol-obesity synergism, we have carried out animal experiments that examine the effects of ethanol administration in genetically obese mice. Lean wild-type (WT) and obese (ob/ob) mice were subjected to ethanol feeding for 4 wk using a modified Lieber-DeCarli diet. After ethanol feeding, the ob/ob mice displayed much more pronounced changes in terms of liver steatosis and elevated plasma levels of alanine aminotransferase and aspartate aminotransferase, indicators of liver injury, compared with control mice. Mechanistic studies showed that ethanol feeding augmented the impairment of hepatic sirtuin 1 (SIRT1)-AMP-activated kinase (AMPK) signaling in the ob/ob mice. Moreover, the impairment of SIRT1-AMPK signaling was closely associated with altered hepatic functional activity of peroxisome proliferator-activated receptor γ coactivator-α and lipin-1, two vital downstream lipid regulators, which ultimately contributed to aggravated fatty liver observed in ethanol-fed ob/ob mice. Taken together, our novel findings suggest that ethanol administration to obese mice exacerbates fatty liver via impairment of the hepatic lipid metabolism pathways mediated largely by a central signaling system, the SIRT1-AMPK axis.

MicroRNA-217 promotes ethanol-induced fat accumulation in hepatocytes by down-regulating SIRT1.

Ethanol-mediated inhibition of hepatic sirtuin 1 (SIRT1) plays a crucial role in the pathogenesis of alcoholic fatty liver disease. Here, we investigated the underlying mechanisms of this inhibition by identifying a new hepatic target of ethanol action, microRNA-217 (miR-217). The role of miR-217 in the regulation of the effects of ethanol was investigated in cultured mouse AML-12 hepatocytes and in the livers of chronically ethanol-fed mice. In AML-12 hepatocytes and in mouse livers, chronic ethanol exposure drastically and specifically induced miR-217 levels and caused excess fat accumulation. Further studies revealed that overexpression of miR-217 in AML-12 cells promoted ethanol-mediated impairments of SIRT1 and SIRT1-regulated genes encoding lipogenic or fatty acid oxidation enzymes. More importantly, miR-217 impairs functions of lipin-1, a vital lipid regulator, in hepatocytes. Taken together, our novel findings suggest that miR-217 is a specific target of ethanol action in the liver and may present as a potential therapeutic target for treating human alcoholic fatty liver disease.

Involvement of E2F1 transcriptional activity in cadmium-induced cell-cycle arrest at G1 in human lung fibroblasts.

Human cadmium (Cd) exposure is associated with cancers of the lung and kidney. Using cDNA microarray analysis, we have recently reported that the expression of E2F1 is reduced by Cd in human lung fibroblasts, indicating the possibility of G1-phase arrest. To test this hypothesis, we investigated the effects of Cd on the cyclin-dependent kinase (CDK2) and retinoblastoma protein (Rb) regulatory pathways in WI38 human lung fibroblasts. We demonstrate here that G1-phase accumulation was induced by Cd in WI38 (wild-type for p53 and Rb), but not in the SV40 large T antigen-transformed variant WI38-VA13 (p53- and Rb-defective). Cd-induced cell-cycle arrest was associated with a decrease in CDK2 protein and with increase in p21 expression and p53 phosphorylation. Cd treatment caused a distinct increase in the formation of p21-cyclin E-CDK2 complex, as revealed by immunoprecipitation. The level of Rb-E2F1 complexes was increased, and the translocation of E2F1 to the nucleus was decreased by Cd treatment. Consequently, the transcriptional activity of E2F1 and the expression of the E2F1 target genes were also decreased by Cd. These results clearly demonstrate that Cd-mediated G1 arrest in WI38 cells is associated with the suppression of Rb phosphorylation and with the inhibition of E2F1 transcriptional activity.

Gene expression analysis of so called asian dust extracts in human acute myeloid leukemia cells.

As the frequency and the intensity of so called Asian dust (AD) events have increased, public concerns about the adverse health effects has spiked sharply over the last two decades. Despite the recent reports on the correlation between AD events and the risk for cardiovascular and respiratory disease, the nature of the toxicity and the degree of the risk are yet largely unknown. In the present study, we investigated the effects of the dichloromethane extract of AD (AD-X) and that of urban dust (NAD-X) collected during a non-AD period on gene expression in HL-60 cells using Illumina Sentrix HumanRef-8 Expression BeadChips. Global changes in gene expression were analyzed after 24 h of incubation with 50 or 100 µg/ml AD-X and NAD-X. By one-way analysis of variance (p < 0.05) and Benjamini-Hochberg multiple testing correction for false discovery rate of the results, 573 and 297 genes were identified as AD-X- and NAD-X-responsive, respectively. The genes were classified into three groups by Venn diagram analysis of their expression profile, i.e., 290 AD-X-specific, 14 NAD-X-specific, and 283 overlapping genes. Quantitative realtime PCR confirmed the changes in the expression levels of the selected genes. The expression patterns of five genes, namely SORL1, RABEPK, DDIT4, AZU1, and NUDT1 differed significantly between the two groups. Following rigorous validation process, these genes may provide information in developing biomarker for AD exposure.

Magnolia officinalis reverses alcoholic fatty liver by inhibiting the maturation of sterol regulatory element-binding protein-1c.

The generally accepted hypothesis for the pathogenesis of alcoholic liver disease (ALD) is the two-hit model, which proposes that fat accumulation in the liver increases the sensitivity of the liver to a second hit that leads to inflammatory liver cell damage. In this study we evaluated the effects of Magnolia officinalis (MO), which contains honokiol and magnolol as the primary pharmacological components, to eradicate fatty liver in rats fed an ethanol diet. In vitro studies showed that MO was able to protect RAW 264.7 cells from ethanol-induced production of tumor necrosis factor-alpha, reactive oxygen species, and superoxide anion radicals; the activation of NADPH oxidase; and subsequent cell death. We also investigated the therapeutic effects of MO on alcoholic fatty liver in Lieber-DeCarli ethanol diet-fed rats. MO treatment of the rats for the last 2 weeks of ethanol feeding completely reversed all the serum, hepatic parameters, and fatty liver changes. The increased maturation of sterol regulatory element-binding protein-1c in the liver by ethanol treatment was completely inhibited by treatment with MO. Therefore, MO may be a promising candidate for development as a therapeutic agent for ALD.

Honokiol reverses alcoholic fatty liver by inhibiting the maturation of sterol regulatory element binding protein-1c and the expression of its downstream lipogenesis genes.

Ethanol induces hepatic steatosis via a complex mechanism that is not well understood. Among the variety of molecules that have been proposed to participate in this mechanism, the sterol regulatory element (SRE)-binding proteins (SREBPs) have been identified as attractive targets for therapeutic intervention. In the present study, we evaluated the effects of honokiol on alcoholic steatosis and investigated its possible effect on the inhibition of SREBP-1c maturation. In in vitro studies, H4IIEC3 rat hepatoma cells developed increased lipid droplets when exposed to ethanol, but co-treatment with honokiol reversed this effect. Honokiol inhibited the maturation of SREBP-1c and its translocation to the nucleus, the binding of nSREBP-1c to SRE or SRE-related sequences of its lipogenic target genes, and the expression of genes for fatty acid synthesis. In contrast, magnolol, a structural isomer of honokiol, had no effect on nSREBP-1c levels. Male Wistar rats fed with a standard Lieber-DeCarli ethanol diet for 4 weeks exhibited increased hepatic triglyceride and decreased hepatic glutathione levels, with concomitantly increased serum alanine aminotransferase and TNF-alpha levels. Daily administration of honokiol (10 mg/kg body weight) by gavage during the final 2 weeks of ethanol treatment completely reversed these effects on hepatotoxicity markers, including hepatic triglyceride, hepatic glutathione, and serum TNF-alpha, with efficacious abrogation of fat accumulation in the liver. Inhibition of SREBP-1c protein maturation and of the expression of Srebf1c and its target genes for hepatic lipogenesis were also observed in vivo. A chromatin immunoprecipitation assay demonstrated inhibition of specific binding of SREBP-1c to the Fas promoter by honokiol in vivo. These results demonstrate that honokiol has the potential to ameliorate alcoholic steatosis by blocking fatty acid synthesis regulated by SREBP-1c.

Analysis of hepatic gene expression during fatty liver change due to chronic ethanol administration in mice.

Chronic consumption of ethanol can cause cumulative liver damage that can ultimately lead to cirrhosis. To explore the mechanisms of alcoholic steatosis, we investigated the global intrahepatic gene expression profiles of livers from mice administered alcohol. Ethanol was administered by feeding the standard Lieber-DeCarli diet, of which 36% (high dose) and 3.6% (low dose) of the total calories were supplied from ethanol for 1, 2, or 4 weeks. Histopathological evaluation of the liver samples revealed fatty changes and punctate necrosis in the high-dose group and ballooning degeneration in the low-dose group. In total, 292 genes were identified as ethanol responsive, and several of these differed significantly in expression compared to those of control mice (two-way ANOVA; p<0.05). Specifically, the expression levels of genes involved in hepatic lipid transport and metabolism were examined. An overall net increase in gene expression was observed for genes involved in (i) glucose transport and glycolysis, (ii) fatty acid influx and de novo synthesis, (iii) fatty acid esterification to triglycerides, and (iv) cholesterol transport, de novo cholesterol synthesis, and bile acid synthesis. Collectively, these data provide useful information concerning the global gene expression changes that occur due to alcohol intake and provide important insights into the comprehensive mechanisms of chronic alcoholic steatosis.

Salvia miltiorrhiza Bunge and its active component cryptotanshinone protects primary cultured rat hepatocytes from acute ethanol-induced cytotoxicity and fatty infiltration.

Alcoholic liver disease involves hepatocellular injury induced by the acute or chronic consumption of ethanol. Fatty infiltration is usually followed by inflammation and focal necrosis, which can lead to cirrhosis if not treated properly in the initial stage. There have been many attempts to develop effective therapies for the disease, using natural products derived from medicinal plants. In this study, we report that the standardized fraction of Salvia miltiorrhiza Bunge (Sm-SF) and its active component, cryptotanshinone, were able to protect hepatocytes from lipopolysaccharide- and ethanol-induced cell death. They also suppressed ethanol-induced lipid accumulation as evidenced by the Nile red binding assay. The ethanol-induced activation and nuclear translocation of sterol regulatory element-binding protein-1 and the consequent transactivation of the target genes involved in fatty acid biosynthesis were inhibited by Sm-SF and cryptotanshinone in a dose-dependent manner. Cryptotanshinone, an active component of S. miltiorrhiza, has the potential to ameliorate alcoholic liver disease by blocking hepatic cell death and fatty acid synthesis.

Effects of tanshinone IIA on the hepatotoxicity and gene expression involved in alcoholic liver disease.

Tanshinone IIA is one of the most abundant constituents of the root of Salvia miltiorrhiza BUNGE which exerts antioxidant and anti-inflammatory actions in many experimental disease models. In the present study, we demonstrated that the standardized fraction of S. miltiorrhiza (Sm-SF) was able to protect RAW 264.7 cells from ethanol-and lipopolysaccharide (LPS)-induced production of superoxide radical, activation of NADPH oxidase and subsequently death of the cells. Among four main components of Sm-SF, tanshinone IIA was the most potent in protecting cells from LPS-and ethanol-induced cytotoxicity. LPS or ethanol induced the expression of CD14, iNOS, and SCD1 and decreased RXR-alpha, which was completely reversed by tanshinone IIA. In H4IIEC3 cells, 10 microM tanshinone IIA effectively blocked ethanol-induced fat accumulation as evidenced by Nile Red binding assay. These results indicate that tanshinone IIA may have potential to inhibit alcoholic liver disease by reducing LPS-and ethanol-induced Kupffer cell sensitization, inhibiting synthesis of reactive oxygen/nitrogen species, inhibiting fatty acid synthesis and stimulating fatty acid oxidation.