Reversible disruption of XPO1-mediated nuclear export inhibits respiratory syncytial virus (RSV) replication.

Respiratory syncytial virus (RSV) is the primary cause of serious lower respiratory tract disease in infants, young children, the elderly and immunocompromised individuals. Therapy for RSV infections is limited to high risk infants and there are no safe and efficacious vaccines. Matrix (M) protein is a major RSV structural protein with a key role in virus assembly. Interestingly, M is localised to the nucleus early in infection and its export into the cytoplasm by the nuclear exporter, exportin-1 (XPO1) is essential for RSV assembly. We have shown previously that chemical inhibition of XPO1 function results in reduced RSV replication. In this study, we have investigated the anti-RSV efficacy of Selective Inhibitor of Nuclear Export (SINE) compounds, KPT-335 and KPT-185. Our data shows that therapeutic administration of the SINE compounds results in reduced RSV titre in human respiratory epithelial cell culture. Within 24 h of treatment, RSV replication and XPO1 expression was reduced, M protein was partially retained in the nucleus, and cell cycle progression was delayed. Notably, the effect of SINE compounds was reversible within 24 h after their removal. Our data show that reversible inhibition of XPO1 can disrupt RSV replication by affecting downstream pathways regulated by the nuclear exporter.

Selinexor: a first-in-class SINE compound for treatment of relapsed refractory multiple myeloma.

The progression of multiple myeloma is accompanied by complex cytogenetic and epigenetic alterations that include mutation or functional inactivation of tumor suppressor proteins and overexpression of oncoproteins. Patients whose myeloma is refractory to the three major classes of drugs including immunomodulatory agents, proteasome inhibitors and anti-CD38 monoclonal antibodies have a very poor prognosis. Drugs with novel mechanisms of action that can bypass resistance mechanisms are sorely needed for this group of patients. Selinexor represents a novel, oral agent with an innovative mechanism of action that offers a significant therapeutic advance in this group of heavily treated patients. Moreover, this novel mechanism may provide additional options for patients with less refractory disease.

Computational Study of Drugs Targeting Nuclear Receptors.

Endocrine-disrupting chemicals have been shown to interfere with the endocrine system function at the level of hormone synthesis, transport, metabolism, binding, action, and elimination. They are associated with several health problems in humans: obesity, diabetes mellitus, infertility, impaired thyroid and neuroendocrine functions, neurodevelopmental problems, and cancer are among them. As drugs are chemicals humans can be frequently exposed to for longer periods of time, special emphasis should be put on their endocrine-disrupting potential. In this study, we conducted a screen of 1046 US-approved and marketed small-molecule drugs (molecular weight between 60 and 600) for estimating their endocrine-disrupting properties. Binding affinity to 12 nuclear receptors was assessed with a molecular-docking program, Endocrine Disruptome. We identified 130 drugs with a high binding affinity to a nuclear receptor that is not their pharmacological target. In a subset of drugs with predicted high binding affinities to a nuclear receptor with Endocrine Disruptome, the positive predictive value was 0.66 when evaluated with in silico results obtained with another molecular docking program, VirtualToxLab, and 0.32 when evaluated with in vitro results from the Tox21 database. Computational screening was proven useful in prioritizing drugs for in vitro testing. We suggest that the novel interactions of drugs with nuclear receptors predicted here are further investigated.

Selinexor for the treatment of multiple myeloma.

Introduction: Despite unprecedented advances in the treatment of multiple myeloma (MM), almost all patients develop a disease that is resistant to the five most commonly used and active anti-MM agents. The prognosis for this patient population is particularly poor resulting in an unmet need for additional therapeutic options. Exportin-1 (XPO-1) is a major nuclear export protein of macromolecular cargo frequently overexpressed in MM. Selinexor is a first-in-class, oral Selective-Inhibitor-of-Nuclear-Export (SINE) compound that impedes XPO-1. Based on results of the STORM-trial, selinexor in combination with dexamethasone was granted accelerated FDA approval for patients with penta-refractory MM in July 2019.Areas covered: This article summarizes our up-to-date knowledge on the pathophysiologic role of XPO-1 in MM. Furthermore, it reviews the most recent clinical data on selinexor in combination with dexamethasone and other anti-MM agents; and discusses its safety profile, management strategies; and potential future developments.Expert opinion: Selinexor represents a next-generation-novel agent with an innovative mechanism of action that marks a significant advance in the treatment of heavily pretreated MM patients. Ongoing studies investigate its therapeutic potential also in earlier lines of therapy. Additional data is needed to confirm that selinexor and other SINE compounds are a valuable addition to our current therapeutic armamentarium.

Selenium-Rich-Yeast Protects Against Aluminum-Induced Activating Nuclear Xenobiotic Receptors and Triggering Inflammation and Cytochromes P450 Systems in Mice Heart.

Aluminum (Al) poisoning is linked to the development of cardiovascular diseases, and dietary supplementation with selenium-rich-yeast (SeY) has been shown to prevent inflammatory conditions. We evaluated the preventive effect of SeY on Al-induced cardiotoxicity, and the possible underlying mechanisms. Mice were treated with SeY (0.1 mg/kg) and/or Al (10 mg/kg) by oral gavage for 4 weeks. Histopathological damage was observed in the heart of Al-treated mice, in addition to the transcriptional up/downregulation of nuclear xenobiotic receptors (NXRs), inflammatory cytokines and 15 CYP450s genes. SeY significantly inhibited these Al-induced histopathological and molecular changes, and restored these indicators to the control levels. These results suggest that SeY exerts a cardio-protective effect against Al-induced toxicity through the NXR system, inflammatory cytokines, and CYP450s genes.

Preclinical Assessment with Clinical Validation of Selinexor with Gemcitabine and Nab-Paclitaxel for the Treatment of Pancreatic Ductal Adenocarcinoma.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) remains a deadly disease urgently requiring new treatments. Overexpression of the protein transporter exportin-1 (XPO1) leads to mislocalization of tumor-suppressor proteins (TSP) and their inactivation. Earlier, we showed that blocking XPO1 by CRISPR/Cas9 validated Selective Inhibitor of Nuclear Export (SINE) compounds (selinexor and analogs) restores the antitumor activity of multiple TSPs leading to suppression of PDAC in vitro and in orthotopic models. EXPERIMENTAL DESIGN: We evaluate the synergy between SINE compounds and standard-of-care treatments in preclinical models and in a PDAC Phase Ib trial. RESULTS: SINE compounds synergize with gemcitabine (GEM) and nanoparticle albumin-bound (nab)-paclitaxel leading to suppression of PDAC cellular growth and cancer stem cell (CSC) spheroids disintegration. Label-free quantitative proteome profiling with nuclear and cytoplasmic enrichment showed superior enhancement in nuclear protein fraction in combination treatment. Selinexor inhibited the growth of PDAC CSC and two patient-derived (PDX) subcutaneous xenografts. Selinexor-GEM-nab-paclitaxel blocked PDX and orthotopic tumor growth. In a phase 1b study (NCT02178436), 9 patients were exposed to selinexor (60 mg oral) with GEM (1,000 mg/m2 i.v.) and nab-paclitaxel (125 mg/m2 i.v.) on days 1, 8, and 15 of 28-day cycle. Two patients showed partial response, and 2 had stable disease. An outstanding, durable objective response was observed in one of the responders with progression-free survival of 16 months and overall survival of 22 months. CONCLUSIONS: Our preclinical and ongoing clinical study lends support to the use of selinexor-GEM-nab-paclitaxel as an effective therapy for metastatic PDAC.

Scalalactams A⁻D, Scalarane Sesterterpenes with a γ-Lactam Moiety from a Korean Spongia Sp. Marine Sponge.

Intensive study on the chemical components of a Korean marine sponge, Spongia sp., has led to the isolation of four new scalarane sesterterpenes, scalalactams A⁻D (1⁻4). Their chemical structures were elucidated from the analysis of spectroscopic data including 1D-and 2D-NMR as well as MS data. Scalalactams A⁻D (1⁻4) possess a scalarane carbon skeleton with a rare structural feature of a γ-lactam moiety within the molecules. Scalalactams A and B (1 and 2) have an extended isopropanyl chain at the lactam ring, and scalalactams C and D (3 and 4) possess a phenethyl group at the lactam ring moiety. Scalalactams A⁻D (1⁻4) did not show FXR antagonistic activity nor cytotoxicity up to 100 µM.

In vitro toxicity and efficacy of verdinexor, an exportin 1 inhibitor, on opportunistic viruses affecting immunocompromised individuals.

Infection of immunocompromised individuals with normally benign opportunistic viruses is a major health burden globally. Infections with viruses such as Epstein-Barr virus (EBV), human cytomegalovirus (HCMV), Kaposi's sarcoma virus (KSHV), adenoviruses (AdV), BK virus (BKPyV), John Cunningham virus (JCPyV), and human papillomavirus (HPV) are significant concerns for the immunocompromised, including when these viruses exist as a co-infection with human immunodeficiency virus (HIV). These viral infections are more complicated in patients with a weakened immune system, and often manifest as malignancies resulting in significant morbidity and mortality. Vaccination is not an attractive option for these immune compromised individuals due to defects in their adaptive immune response. Verdinexor is part of a novel class of small molecules known as SINE (Selective Inhibitor of Nuclear Export) compounds. These small molecules demonstrate specificity for the nuclear export protein XPO1, to which they bind and block function, resulting in sequestration of XPO1-dependent proteins in the nucleus of the cell. In antiviral screening, verdinexor demonstrated varying levels of efficacy against all of the aforementioned viruses including previously with HIV. Studies by other labs have discussed likely mechanisms of action for verdinexor (ie. XPO1-dependence) against each virus. GLP toxicology studies suggest that anti-viral activity can be achieved at a tolerable dose range, based on the safety profile of a previous phase 1 clinical trial of verdinexor in healthy human volunteers. Taken together, these results indicate verdinexor has the potential to be a broad spectrum antiviral for immunocompromised subjects for which vaccination is a poor option.

Hypolipidemic effect of SIPI-7623, a derivative of an extract from oriental wormwood, through farnesoid X receptor antagonism.

Farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors. As a metabolic regulator, FXR plays key roles in bile acid and cholesterol metabolism and lipid and glucose homeostasis. Therefore, FXR is a potential drug target for several metabolic syndromes, especially those related to lipidemia disorders. In the present study, we identified small molecule SIPI-7623, a derivative of an extract from Oriental wormwood (Artemisia capillaris), and found that it specifically upregulated the expression of cholesterol-7-alpha-hydroxylase (CYP7A1), downregulated the expression of sterol-regulatory element-binding protein 1c (SREBP-1c) in the liver, and inhibited the expression of ileal bile acid binding-protein (IBABP) in the ileum of rats. We found that inhibition of FXR by SIPI-7623 decreased the level of cholesterol and triglyceride. SIPI-7623 reduced the levels of cholesterol and triglyceride in in vitro HepG2 cell models, ameliorated diet-induced atherosclerosis, and decreased the serum lipid content on rats and rabbits model of atherosclerosis in vivo. Furthermore, SIPI-7623 decreased the extent of atherosclerotic lesions. Our resutls demonstrated that antagonism of the FXR pathway can be employed as a therapeutic strategy to treat metabolic diseases such as hyperlipidemia and atherosclerosis. In conclusion, SIPI-7623 could be a promising lead compound for development of drugs to treat hyperlipidemia and atherosclerosis.

In silico estrogen-like activity and in vivo osteoclastogenesis inhibitory effect of Cicer arietinum extract.

Postmenopausal osteoporosis is a common disorder accompanied with estrogen deficiency in women. Plants containing phytoestrogens and amino acids have been used in the osteoporosis treatment. The present study aims to evaluate the estrogen-like activity of the Cicer arietinum extract (CAE) and its ability to inhibit osteoclastogenesis process. These achieved by investigating the binding of its active phytoestrogens (genistein, daidzein, formononetin and biochanin A) to the estrogen receptors (ER) α and ß of rats and human in silico. In addition, in vivo study on ovariectomized (OVX) rats is performed. For in vivo study, twenty four rats were divided into four groups (n= 6). Group I is the sham control rats which administered distilled water. Groups II, III, and IV are OVX groups which administered distilled water, CAE (500 mg/kg), and alendronate; respectively. The docking study revealed that the phytoestrogens docked into the protein active site with binding energies comparable with that of estrogens (estriol and ß-estradiol) which means the similarity between the estrogenic contents of CAE and the ensogenous ones. Additionally, in vivo study revealed that CAE reverse TRAP5b and RANKL levels that drastically increased in the untreated OVX group. But, it trigger upregulation of OPG, enhance the OPG/RANKL ratio and modulate the bone and uterus alterations of OVX group. Phytoestrogens and the bone-protective amino acids contents of CAE could be responsible for their estrogen-like effect and antiosteoporotic activity. These results concluded that CAE is an attractive candidate for developing a potential therapeutic cheap agent used as an alternative to the synthetic estrogen replacement therapy. Further, in vivo validation is required for its clinical application.

FoxO-1 contributes to the efficacy of the combination of the XPO1 inhibitor selinexor and cisplatin in ovarian carcinoma preclinical models.

The XPO1/CRM1 inhibitor selinexor (KPT-330), is currently being evaluated in multiple clinical trials as an anticancer agent. XPO1 participates in the nuclear export of FoxO-1, which we previously found to be decreased in platinum-resistant ovarian carcinoma. The aim of this study was to determine whether enriching FoxO-1 nuclear localization using selinexor would increase ovarian cancer cell sensitivity to cisplatin. Selinexor, as a single agent, displayed a striking antiproliferative effect in different ovarian carcinoma cell lines. A schedule-dependent synergistic effect of selinexor in combination with cisplatin was found in cisplatin-sensitive IGROV-1, the combination efficacy being more evident in sensitive than in the resistant cells. In IGROV-1 cells, the combination was more effective when selinexor followed cisplatin exposure. A modulation of proteins involved in apoptosis (p53, Bax) and in cell cycle progression (p21WAF1) was found by Western blotting. Selinexor-treated cells exhibited enriched FoxO-1 nuclear staining. Knock-down experiments with RNA interference indicated that FOXO1-silenced cells displayed a reduced sensitivity to selinexor. FOXO1 silencing also tended to reduce the efficacy of the drug combination at selected cisplatin concentrations. Selinexor significantly inhibited tumor growth, induced FoxO-1 nuclear localization and improved the efficacy of cisplatin in IGROV-1 xenografts. Taken together, our results support FoxO-1 as one of the key factors promoting sensitivity towards selinexor and the synergistic interaction between cisplatin and selinexor in ovarian carcinoma cells with selected molecular backgrounds, highlighting the need for treatment regimens tailored to the molecular tumor features.

Atrazine-induced environmental nephrosis was mitigated by lycopene via modulating nuclear xenobiotic receptors-mediated response.

The burden and morbidity of environmental nephrosis is increasing globally. Atrazine (ATR) and degradation products in the environment are considered key determinants of nephrosis. However, the lack of highly effective treatments for environmental nephrosis creates an urgent need to better understand the preventive strategies and mechanisms. This study aimed to highlight the mechanism of ATR-induced environmental nephrosis and the chemoprotective potential of lycopene (LYC) against the renal injury and nephrosis. Male mice were treated with LYC (5 mg/kg) and/or ATR (50 mg/kg or 200 mg/kg) by gavage administration for 21 days. Histopathological changes and biochemical function, cytochrome P450 enzymes system (CYP450s), nuclear xenobiotic receptors (NXRs) response and the transcription of CYP isoforms (CYPs) were detected. ATR exposure caused the changes of the histopathological and biochemical function, activated the NXR response and disturbed the CYP450s homeostasis. Supplementary LYC significantly prevented ATR-induced nephrotoxicity and alleviated the alternation of histopathological and biochemical function via modulating the CYP450s homeostasis and the NXR response. The results demonstrated AHR, CAR, PXR, PPAR (α, γ), CYP1, CYP2, CYP3 and CYP4 superfamily play a vital role in LYC-ATR interaction. Our findings provide new evidence that ATR exposure can cause the environmental nephrosis via inducing the kidney injury. Supplementary LYC showed significant chemoprotective potential against ATR-induced renal injury and environmental nephrosis via regulating the NXR response and the CYP450s homeostasis.

Discovery of Farnesoid X Receptor Antagonists Based on a Library of Oleanolic Acid 3-O-Esters through Diverse Substituent Design and Molecular Docking Methods.

The pentacyclic triterpene oleanolic acid (OA, 1) with known farnesoid X receptor (FXR) modulatory activity was modified at its C-3 position to find new FXR-interacting agents. A diverse substitution library of OA derivatives was constructed in silico through a 2D fingerprint similarity cluster strategy. With further docking analysis, four top-scored OA 3-O-ester derivatives were selected for synthesis. The bioassay results indicated that all four compounds 3 inhibited chenodeoxycholic acid (CDCA)-induced FXR transactivation in a concentration-dependent mode. Among them 3b and 3d are more active than the parent compound OA. A molecular simulation study was performed to attempt to explain the structure-activity relationship (SAR) and the antagonistic action. To the best of our knowledge, this is the first report on semi-synthetic pentacyclic triterpenoids with FXR-modulatory activities.

Alisol B 23-acetate protects against non-alcoholic steatohepatitis in mice via farnesoid X receptor activation.

Alisol B 23-acetate (AB23A) is a natural triterpenoid isolated from the traditional Chinese medicine rhizoma alismatis, which exhibits a number of pharmacological activities, including anti-hepatitis virus, anti-cancer and antibacterial effects. In this study we examined whether AB23A protected against non-alcoholic steatohepatitis (NASH) in mice, and the mechanisms underlying the protective effects. NASH was induced in mice fed a methionine and choline-deficient (MCD) diet for 4 weeks. The mice were simultaneously treated with AB23A (15, 30, and 60 mg·kg-1·d-1, ig) for 4 weeks. On the last day, blood samples and livers were collected. Serum liver functional enzymes, inflammatoru markers were assessed. The livers were histologically examined using H&E, Oil Red O, Masson's trichrome and Sirius Red staining. Mouse primary hepatocytes were used for in vitro experiments. The mechanisms underlying AB23A protection were analyzed using siRNA, qRT-PCR, and Western blot assays. AB23A treatment significantly and dose-dependently decreased the elevated levels of serum ALT and AST in MCD diet-fed mice. Furthermore, AB23A treatment significantly reduced hepatic triglyceride accumulation, inflammatory cell infiltration and hepatic fibrosis in the mice. AB23A-induced decreases in serum and hepatic lipids were related to decreased hepatic lipogenesis through decreasing hepatic levels of SREBP-1c, FAS, ACC1 and SCD1 and increased lipid metabolism via inducing PPARα, CPT1α, ACADS and LPL. The reduction in inflammatory cell infiltration corresponded to deceased serum levels of mKC and MCP-1 and decreased hepatic gene expression of MCP-1 and VCAM-1. The reduction in hepatic fibrosis was correlated with decreased hepatic gene expression of fibrosis markers. The protective effects of AB23A were FXR-dependent, because treatment with the FXR agonist CDCA mimicked AB23A-induced hepato-protection in the mice, whereas co-administration of FXR antagonist guggulsterone abrogated AB23A-induced hepato-protection. In mouse primary hepatocytes, FXR gene silencing abrogated AB23A-induced changes in gene expression of Apo C-II, CPT1α, ACADS and LPL. AB23A produces protective effects against NASH in mice via FXR activation.

Discovery and SAR study of 3-(tert-butyl)-4-hydroxyphenyl benzoate and benzamide derivatives as novel farnesoid X receptor (FXR) antagonists.

3-(tert-Butyl)-4-hydroxyphenyl 2,4-dichlorobenzoate (1) was discovered in our in-house high throughput screening as a moderate FXR antagonist. To improve the potency and the stability of the hit 1, forty derivatives were synthesized and SAR was systematically explored. The results turn out that replacing the 2,4-dichlorophenyl with 2,6-dichloro-4-amidophenyl shows great improvement in potency, replacing the benzoate with benzamide shows improvement in stability and slight declining of potency and 3-(tert-butyl)-4-hydroxyphenyl unit is essential in obtaining the FXR antagonistic activity.

Soluble guanylate cyclase modulators blunt hyperoxia effects on calcium responses of developing human airway smooth muscle.

Exposure to moderate hyperoxia in prematurity contributes to subsequent airway dysfunction and increases the risk of developing recurrent wheeze and asthma. The nitric oxide (NO)-soluble guanylate cyclase (sGC)-cyclic GMP (cGMP) axis modulates airway tone by regulating airway smooth muscle (ASM) intracellular Ca(2+) ([Ca(2+)]i) and contractility. However, the effects of hyperoxia on this axis in the context of Ca(2+)/contractility are not known. In developing human ASM, we explored the effects of novel drugs that activate sGC independent of NO on alleviating hyperoxia (50% oxygen)-induced enhancement of Ca(2+) responses to bronchoconstrictor agonists. Treatment with BAY 41-2272 (sGC stimulator) and BAY 60-2770 (sGC activator) increased cGMP levels during exposure to 50% O2. Although 50% O2 did not alter sGCα1 or sGCß1 expression, BAY 60-2770 did increase sGCß1 expression. BAY 41-2272 and BAY 60-2770 blunted Ca(2+) responses to histamine in cells exposed to 50% O2. The effects of BAY 41-2272 and BAY 60-2770 were reversed by protein kinase G inhibition. These novel data demonstrate that BAY 41-2272 and BAY 60-2770 stimulate production of cGMP and blunt hyperoxia-induced increases in Ca(2+) responses in developing ASM. Accordingly, sGC stimulators/activators may be a useful therapeutic strategy in improving bronchodilation in preterm infants.

Magnesium Lithospermate B Implicates 3'-5'-Cyclic Adenosine Monophosphate/Protein Kinase A Pathway and N-Methyl-d-Aspartate Receptors in an Experimental Traumatic Brain Injury.

OBJECTIVE: Decreased 3'-5'-cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), and increased N-methyl-d-aspartate (NMDA) related apoptosis were observed in traumatic brain injury (TBI). It is of interest to examine the effect of magnesium lithospermate B (MLB) on cAMP/PKA pathway and NMDAR in TBI. METHODS: A rodent weight-drop TBI model was used. Administration of MLB was initiated 1 week before (precondition) and 24 hours later (reversal). Cortical homogenates were harvested to measure cAMP (enzyme-linked immunosorbent assay), soluble guanylyl cyclases, PKA and NMDA receptor-2ß (Western blot). In addition, cAMP kinase antagonist and H-89 dihydrochloride hydrate were used to test MLB's effect on the cytoplasm cAMP/PKA pathway after TBI. RESULTS: Morphologically, vacuolated neuron and activated microglia were observed in the TBI groups but absent in the MLB preconditioning and healthy controls. Induced cAMP, soluble guanylyl cyclase α1, and PKA were observed in the MLB groups, when compared with the TBI group (P < 0.01) Administration of H-89 dihydrochloride hydrate reversed the effect of MLB on cortical PKA and NMDA-2ß expression after TBI. CONCLUSIONS: This study showed that MLB exerted an antioxidant effect on the enhancement of cytoplasm cAMP and PKA. This compound also decreased NMDA-2ß levels, which may correspond to its neuroprotective effects. This finding lends credence to the presumption that MLB modulates the NMDA-2ß neurotoxicity through a cAMP-dependent mechanism in the pathogenesis of TBI.

Nuclear export inhibitors avert progression in preclinical models of inflammatory demyelination.

Axonal damage has been associated with aberrant protein trafficking. We examined a newly characterized class of compounds that target nucleo-cytoplasmic shuttling by binding to the catalytic groove of the nuclear export protein XPO1 (also known as CRM1, chromosome region maintenance protein 1). Oral administration of reversible CRM1 inhibitors in preclinical murine models of demyelination significantly attenuated disease progression, even when started after the onset of paralysis. Clinical efficacy was associated with decreased proliferation of immune cells, characterized by nuclear accumulation of cell cycle inhibitors, and preservation of cytoskeletal integrity even in demyelinated axons. Neuroprotection was not limited to models of demyelination, but was also observed in another mouse model of axonal damage (that is, kainic acid injection) and detected in cultured neurons after knockdown of Xpo1, the gene encoding CRM1. A proteomic screen for target molecules revealed that CRM1 inhibitors in neurons prevented nuclear export of molecules associated with axonal damage while retaining transcription factors modulating neuroprotection.

Dietary hyodeoxycholic acid exerts hypolipidemic effects by reducing farnesoid X receptor antagonist bile acids in mouse enterohepatic tissues.

Mice were fed a control diet or a diet supplemented with hyodeoxycholic acid, the most abundant bile acid contained in pig bile, for 4 weeks, after which their serum and livers were collected. The contents of total fatty acids of serum and liver cholesteryl esters, and of liver triglycerides, were reduced following the administration of the hyodeoxycholic acid-supplemented diet, which was mainly due to the reductions in the contents of monounsaturated fatty acids. Free cholesterol contents in the serum and liver were not changed by hyodeoxycholic acid administration. Hyodeoxycholic acid administration reduced the gene expression levels of sterol regulatory element binding protein 1c, acetyl-CoA carboxylase, fatty acid synthase, and stearoyl-CoA desaturase-1. Hyodeoxycholic acid administration markedly changes the ratio of FXR-antagonist/FXR-agonist bile acids in the enterohepatic tissues of the mice (1.13 and 7.60 in hyodeoxycholic acid and control diet groups, respectively). Our findings demonstrate that hyodeoxycholic acid administration exerts the hypolipidemic effect in mice, in which downregulations of de novo lipogenesis and desaturation of saturated fatty acids are suggested to play important roles. In addition, regulation of FXR activation through the selective modification of the enterohepatic bile acid pool may be involved in the hypolipidemic effect of hyodeoxycholic acid administration.

Knockdown of the NHR-8 nuclear receptor enhanced sensitivity to the lipid-reducing activity of alkaloids in Caenorhabditis elegans.

Caenorhabditis elegans is a versatile, whole-organism model for bioactivity screening. However, this worm has extensive defensive mechanisms against xenobiotics which limit its use for screening of pharmacologically active compounds. In this study, we report that knockdown of nhr-8, a gene involved in the xenobiotic response, increased the worm's sensitivity to the lipid-reducing effects of some isoquinoline alkaloids, especially berberine. On the other hand, crude extract of rhizome and cultured cells showed enhanced biological activity compared to the pure alkaloids in wild type worm, but this enhanced activity was not detected in nhr-8 RNAi worm, suggesting that some components in cell extracts might interfere with the defense response in this worm. The possibility of using C. elegans as a model for screening bioactive chemicals is discussed.