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1.
Article in English | MEDLINE | ID: mdl-29626711

ABSTRACT

The discovery of cell free fetal DNA in maternal plasma has stimulated a rapid development of non-invasive prenatal testing. The recent advent of massively parallel sequencing has allowed the analysis of circulating cell-free fetal DNA to be performed with unprecedented sensitivity and precision. It is thus expected that plasma DNA-based non invasive prenatal testing will play an increasingly important role in the future of obstetric care. The present review summarizes recent advances in non invasive prenatal testing using cell free fetal DNA. The importance of genetic counseling, the current guidelines for the use of cffDNA screening in pregnancy, as well as specific maternal conditions that can affect the performance of non invasive prenatal testing are also discussed in this review.


Subject(s)
Aneuploidy , Cell-Free Nucleic Acids , Prenatal Diagnosis , Female , Genetic Counseling , Genetic Testing , High-Throughput Nucleotide Sequencing , Humans , Pregnancy
2.
Acta Cardiol ; 72(1): 2-8, 2017 Feb.
Article in English | MEDLINE | ID: mdl-28597734

ABSTRACT

Atherosclerosis and its late sequels are still the number one cause of death in Western societies. Platelets are a driving force not only during the genesis of atherosclerosis, but especially in its late stages, as evidenced by complications such as arterial thrombosis, myocardial infarction, and ischaemic stroke. Platelets are small, anucleate blood elements of critical importance in cardiovascular disease, a major cause of morbidity and mortality. Numerous risk scores exist to identify healthy individuals at increased risk of developing atherosclerosis and cardiovascular disease. However, markers of cardiovascular risk not routinely assessed (i.e. platelet activity, mean platelet volume and P-selectin) may also contribute to be useful in calculating cardiovascular risk. The present review and meta-analysis summarizes the evidence for measuring platelet function indices to identify patients at risk of developing cardiovascular events.


Subject(s)
Blood Platelets/physiology , Cardiovascular Diseases , Platelet Aggregation Inhibitors/therapeutic use , Cardiovascular Diseases/blood , Cardiovascular Diseases/drug therapy , Cardiovascular Diseases/epidemiology , Global Health , Humans , Incidence , Mean Platelet Volume , Platelet Function Tests , Risk Factors , Survival Rate
3.
Sci Rep ; 6: 29320, 2016 07 06.
Article in English | MEDLINE | ID: mdl-27381677

ABSTRACT

Bile acids are signaling molecules interacting with nuclear receptors and membrane G-protein-coupled receptors. Among these receptors, the farnesoid X receptor (FXR) and the membrane G-coupled receptor (GPBAR1) have gained increasing consideration as druggable receptors and their exogenous dual regulation represents an attractive strategy in the treatment of enterohepatic and metabolic disorders. However, the therapeutic use of dual modulators could be associated to severe side effects and therefore the discovery of selective GPBAR1 and FXR agonists is an essential step in the medicinal chemistry optimization of bile acid scaffold. In this study, a new series of 6-ethylcholane derivatives modified on the tetracyclic core and on the side chain has been designed and synthesized and their in vitro activities on FXR and GPBAR1 were assayed. This speculation resulted in the identification of compound 7 as a potent and selective GPBAR1 agonist and of several derivatives showing potent dual agonistic activity.


Subject(s)
Bile Acids and Salts/chemical synthesis , Bile Acids and Salts/metabolism , Gastrointestinal Agents/chemical synthesis , Gastrointestinal Agents/metabolism , Receptors, Cytoplasmic and Nuclear/agonists , Receptors, G-Protein-Coupled/agonists , HEK293 Cells , Hep G2 Cells , Humans , Molecular Structure
4.
Sci Rep ; 6: 19008, 2016 Jan 07.
Article in English | MEDLINE | ID: mdl-26740187

ABSTRACT

Bile acids are the endogenous modulators of the nuclear receptor FXR and the membrane receptor GPBAR1. FXR represents a promising pharmacological target for the treatment of cholestatic liver disorders. Currently available semisynthetic bile acid derivatives cover the same chemical space of bile acids and therefore they are poorly selective toward BA receptors, increasing patient risk for adverse side effects. In this report, we have investigated around the structure of CDCA describing the synthesis and the in vitro and in vivo pharmacological characterization of a novel family of compounds modified on the steroidal tetracyclic core and on the side chain. Pharmacological characterization resulted in the identification of several potent and selective FXR agonists. These novel agents might add utility in the treatment of cholestatic disorders by potentially mitigating side effects linked to unwanted activation of GPBAR1.


Subject(s)
Cholic Acids/pharmacology , Receptors, Cytoplasmic and Nuclear/agonists , Receptors, Cytoplasmic and Nuclear/metabolism , Animals , Cholic Acids/chemical synthesis , Drug Evaluation, Preclinical , HEK293 Cells , Hep G2 Cells , Humans , Inhibitory Concentration 50 , Mice, Inbred C57BL , Receptors, G-Protein-Coupled/agonists , Transcriptional Activation/drug effects
5.
Steroids ; 105: 59-67, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26607331

ABSTRACT

Bile acids, the end products of cholesterol metabolism, activate multiple mechanisms through the interaction with membrane G-protein coupled receptors including the bile acid receptor GPBAR1 and nuclear receptors such as the bile acid sensor, farnesoid X receptor (FXR). Even if dual FXR/GPBAR1 agonists are largely considered a novel opportunity in the treatment of several liver and metabolic diseases, selective targeting of one of these receptors represents an attractive therapeutic approach for a wide range of disorders in which dual modulation is associated to severe side effects. In the present study we have investigated around the structure of LCA generating a small library of cholane derivatives, endowed with dual FXR agonism/GPBAR1 antagonism. To the best of our knowledge, this is the first report of bile acid derivatives able to antagonize GPBAR1.


Subject(s)
Bile Acids and Salts/pharmacology , Cholic Acids/pharmacology , Receptors, Cytoplasmic and Nuclear/metabolism , Receptors, G-Protein-Coupled/metabolism , Bile Acids and Salts/chemistry , Cholic Acids/chemistry , HEK293 Cells , Hep G2 Cells , Humans , Receptors, Cytoplasmic and Nuclear/genetics , Receptors, G-Protein-Coupled/genetics , Transcriptional Activation/drug effects
6.
PLoS One ; 10(11): e0141082, 2015.
Article in English | MEDLINE | ID: mdl-26539823

ABSTRACT

BACKGROUND: GPBAR1 is a bile acids activated receptor expressed in entero-hepatic tissues. In the liver expression of GPBAR1 is restricted to sinusoidal and Kuppfer cells. In the systemic circulation vasodilation caused by GPBAR1 agonists is abrogated by inhibition of cystathione-γ-liase (CSE), an enzyme essential to the generation of hydrogen sulfide (H2S), a vasodilatory agent. Portal BAR501 is a semisynthetic bile acid derivative endowed with a potent and selective agonistic activity toward GPBAR1. METHODS: Cirrhosis was induced in mice by carbon tetrachloride (CCL4) administration for 9 weeks. Liver endothelial dysfunction was induced by feeding wild type and Gpbar1-/- mice with methionine for 4 weeks. In both models, mice were administered BAR501, 15 mg/kg/day. RESULTS: By transactivation assay we demonstrate that BAR501 is a selective GPBAR1 agonist devoid of any FXR agonistic activity. In naïve rats, BAR501 effectively reduced hepatic perfusion pressure and counteracted the vasoconstriction activity of norepinephrine. In the CCl4 model, 9 weeks treatment with BAR501 effectively protected against development of endothelial dysfunction by increasing liver CSE expression and activity and by reducing endothelin (ET)-1 gene expression. In mice feed methionine, treatment with BAR501 attenuated endothelial dysfunction and caused a GPBAR1-dependent regulation of CSE. Using human liver sinusoidal cells, we found that modulation of CSE expression/activity is mediated by both genomic (recruitment of CREB to CRE in the CSE promoter) and non-genomic effects, involving a Akt-dependent phosporylation of CSE and endothelial nitric oxide (NO) synthase (eNOS). BAR501, phosphorylates FOXO1 and inhibits ET-1 transcription in liver sinusoidal cells. CONCLUSIONS: BAR501, a UDCA-like GPBAR1 agonist, rescues from endothelial dysfunction in rodent models of portal hypertension by exerting genomic and non-genomic effects on CSE, eNOS and ET-1 in liver sinusoidal cells.


Subject(s)
Endothelin-1/physiology , Endothelium, Vascular/drug effects , Hydrogen Sulfide/metabolism , Hypertension, Portal/physiopathology , Receptors, G-Protein-Coupled/agonists , Animals , Bile Acids and Salts/metabolism , Cholestanols/pharmacology , Endothelium, Vascular/physiopathology , Forkhead Box Protein O1 , Forkhead Transcription Factors/physiology , Humans , Hypertension, Portal/drug therapy , Liver/metabolism , Male , Mice , Mice, Inbred C57BL , Oncogene Protein v-akt/physiology , Rats , Rats, Wistar , Real-Time Polymerase Chain Reaction , Receptors, G-Protein-Coupled/physiology , Signal Transduction/drug effects , Signal Transduction/physiology , Ursodeoxycholic Acid/analogs & derivatives
7.
Sci Rep ; 5: 16605, 2015 Nov 16.
Article in English | MEDLINE | ID: mdl-26567894

ABSTRACT

Bile acids can regulate nutrient metabolism through the activation of the cell membrane receptor GPBAR1 and the nuclear receptor FXR. Developing an exogenous control over these receptors represents an attractive strategy for the treatment of enterohepatic and metabolic disorders. A number of dual GPBAR1/FXR agonists are known, however their therapeutic use is limited by multiple unwanted effects due to activation of the diverse downstream signals controlled by the two receptors. On the other hand, designing selective GPBAR1 and FXR agonists is challenging since the two proteins share similar structural requisites for ligand binding. Here, taking advantage of our knowledge of the two targets, we have identified through a rational drug design study a series of amine lithocholic acid derivatives as selective GPBAR1 agonists. The presence of the 3α-NH2 group on the steroidal scaffold is responsible for the selectivity over FXR unveiling unprecedented structural insights into bile acid receptors activity modulation.


Subject(s)
Lithocholic Acid/analogs & derivatives , Lithocholic Acid/pharmacology , Receptors, G-Protein-Coupled/agonists , Binding Sites , Dose-Response Relationship, Drug , Drug Design , Gene Expression , HEK293 Cells , Hep G2 Cells , Humans , Lithocholic Acid/chemical synthesis , Molecular Docking Simulation , Molecular Targeted Therapy , Protein Binding , Receptors, G-Protein-Coupled/chemistry , Receptors, G-Protein-Coupled/metabolism , Transcriptional Activation/drug effects
8.
Sci Rep ; 5: 15403, 2015 Oct 15.
Article in English | MEDLINE | ID: mdl-26469385

ABSTRACT

Liver disease is the second most common cause of mortality in HIV-infected persons. Exactly how HIV infection per se affects liver disease progression is unknown. Here we have investigated mRNA expression of 49 nuclear hormone receptors (NRs) and 35 transcriptional coregulators in HepG2 cells upon stimulation with the HIV matrix protein p17. This viral protein regulated mRNA expression of some NRs among which LXRα and its transcriptional co-activator MED1 were highly induced at mRNA level. Dissection of p17 downstream intracellular pathway demonstrated that p17 mediated activation of Jak/STAT signaling is responsible for the promoter dependent activation of LXR. The treatment of both HepG2 as well as primary hepatocytes with HIV p17 results in the transcriptional activation of LXR target genes (SREBP1c and FAS) and lipid accumulation. These effects are lost in HepG2 cells pre-incubated with a serum from HIV positive person who underwent a vaccination with a p17 peptide as well as in HepG2 cells pre-incubated with the natural LXR antagonist gymnestrogenin. These results suggest that HIV p17 affects NRs and their related signal transduction thus contributing to the progression of liver disease in HIV infected patients.


Subject(s)
HIV/metabolism , Lipid Metabolism , Liver/metabolism , Peptide Fragments/metabolism , env Gene Products, Human Immunodeficiency Virus/metabolism , AIDS Vaccines/immunology , Animals , Cells, Cultured , Cholesterol/analogs & derivatives , Cholesterol/analysis , Hep G2 Cells , Hepatocytes/cytology , Hepatocytes/metabolism , Humans , Lipid Metabolism/drug effects , Liver X Receptors , Mediator Complex Subunit 1/genetics , Mediator Complex Subunit 1/metabolism , Mice , Mice, Inbred C57BL , Orphan Nuclear Receptors/antagonists & inhibitors , Orphan Nuclear Receptors/genetics , Orphan Nuclear Receptors/metabolism , Peptide Fragments/genetics , Peptide Fragments/pharmacology , Receptors, Cytoplasmic and Nuclear/genetics , Receptors, Cytoplasmic and Nuclear/metabolism , Recombinant Proteins/biosynthesis , Recombinant Proteins/immunology , Recombinant Proteins/pharmacology , STAT Transcription Factors/chemistry , STAT Transcription Factors/metabolism , Signal Transduction/drug effects , Sterol Regulatory Element Binding Protein 1/genetics , Sterol Regulatory Element Binding Protein 1/metabolism , Trans-Activators/genetics , Trans-Activators/metabolism , Transcriptional Activation/drug effects , env Gene Products, Human Immunodeficiency Virus/genetics , env Gene Products, Human Immunodeficiency Virus/pharmacology
9.
PLoS One ; 10(7): e0129866, 2015.
Article in English | MEDLINE | ID: mdl-26177448

ABSTRACT

BACKGROUND & AIMS: In cholestatic syndromes, body accumulation of bile acids is thought to cause itching. However, the mechanisms supporting this effect remain elusive. Recently, GPBAR1 (TGR5) a G-protein coupled receptor has been shown to mediate itching caused by intradermal administration of DCA and LCA. 6α-ethyl-3α, 7α-dihydroxy-24-nor-5ß-cholan-23-ol (BAR502) is a non-bile acid dual ligand for FXR and GPBAR1. METHODS: Cholestasis was induced in wild type and GPBAR1-/- mice by administration of α-naphthyl-isothiocyanate (ANIT) or 17α-ethynylestradiol. RESULTS: In naïve mice skin application of DCA, TLCA, 6-ECDCA, oleanolic and betulinic acid induces a GPBAR1 dependent pruritogenic response that could be desensitized by re-challenging the mice with the same GPBAR1 agonist. In wild type and GPBAR1-/- mice cholestasis induced by ANIT fails to induce spontaneous itching and abrogates scratching behavior caused by intradermal administration of DCA. In this model, co-treatment with BAR502 increases survival, attenuates serum alkaline phosphatase levels and robustly modulates the liver expression of canonical FXR target genes including OSTα, BSEP, SHP and MDR1, without inducing pruritus. Betulinic acid, a selective GPBAR1 ligand, failed to rescue wild type and GPBAR1-/- mice from ANIT cholestasis but did not induced itching. In the 17α-ethynylestradiol model BAR502 attenuates cholestasis and reshapes bile acid pool without inducing itching. CONCLUSIONS: The itching response to intradermal injection of GPBAR1 agonists desensitizes rapidly and is deactivated in models of cholestasis, explain the lack of correlation between bile acids levels and itching severity in cholestatic syndromes. In models of non-obstructive cholestasis, BAR502 attenuates liver injury without causing itching.


Subject(s)
Cholestasis/complications , Pruritus/metabolism , Pruritus/pathology , Receptors, G-Protein-Coupled/metabolism , Signal Transduction , Animals , Bile Acids and Salts/adverse effects , Bile Acids and Salts/blood , Chemical and Drug Induced Liver Injury/genetics , Chemical and Drug Induced Liver Injury/metabolism , Cholanes/metabolism , Cholanes/pharmacology , Cholestasis/chemically induced , Cholestasis/physiopathology , Cholestasis/prevention & control , Disease Models, Animal , Estrogens/adverse effects , Gene Deletion , Isothiocyanates/adverse effects , Ligands , Male , Mice , Pruritus/chemically induced , Pruritus/complications , Receptors, Cytoplasmic and Nuclear/metabolism , Receptors, G-Protein-Coupled/deficiency , Receptors, G-Protein-Coupled/genetics
10.
Am J Physiol Heart Circ Physiol ; 309(1): H114-26, 2015 Jul 01.
Article in English | MEDLINE | ID: mdl-25934094

ABSTRACT

GPBAR1 is a bile acid-activated receptor (BAR) for secondary bile acids, lithocholic (LCA) and deoxycholic acid (DCA), expressed in the enterohepatic tissues and in the vasculature by endothelial and smooth muscle cells. Despite that bile acids cause vasodilation, it is unclear why these effects involve GPBAR1, and the vascular phenotype of GPBAR1 deficient mice remains poorly defined. Previous studies have suggested a role for nitric oxide (NO) in regulatory activity exerted by GPBAR1 in liver endothelial cells. Hydrogen sulfide (H2S) is a vasodilatory agent generated in endothelial cells by cystathionine-γ-lyase (CSE). Here we demonstrate that GPBAR1 null mice had increased levels of primary and secondary bile acids and impaired vasoconstriction to phenylephrine. In aortic ring preparations, vasodilation caused by chenodeoxycholic acid (CDCA), a weak GPBAR1 ligand and farnesoid-x-receptor agonist (FXR), was iberiotoxin-dependent and GPBAR1-independent. In contrast, vasodilation caused by LCA was GPBAR1 dependent and abrogated by propargyl-glycine, a CSE inhibitor, and by 5ß-cholanic acid, a GPBAR1 antagonist, but not by N(5)-(1-iminoethyl)-l-ornithine (l-NIO), an endothelial NO synthase inhibitor, or iberiotoxin, a large-conductance calcium-activated potassium (BKCa) channels antagonist. In venular and aortic endothelial (HUVEC and HAEC) cells GPBAR1 activation increases CSE expression/activity and H2S production. Two cAMP response element binding protein (CREB) sites (CREs) were identified in the CSE promoter. In addition, TLCA stimulates CSE phosphorylation on serine residues. In conclusion we demonstrate that GPBAR1 mediates the vasodilatory activity of LCA and regulates the expression/activity of CSE. Vasodilation caused by CDCA involves BKCa channels. The GPBAR1/CSE pathway might contribute to endothelial dysfunction and hyperdynamic circulation in liver cirrhosis.


Subject(s)
Aorta/metabolism , Bile Acids and Salts/metabolism , Cystathionine gamma-Lyase/genetics , Hydrogen Sulfide/metabolism , Receptors, G-Protein-Coupled/genetics , Vasodilation/genetics , Animals , Aorta/drug effects , Bile Acids and Salts/pharmacology , Chenodeoxycholic Acid/pharmacology , Cholic Acids/pharmacology , Cystathionine gamma-Lyase/metabolism , Endothelial Cells , Gene Expression Regulation , Human Umbilical Vein Endothelial Cells , Humans , Lithocholic Acid/pharmacology , Mice, Knockout , Ornithine/analogs & derivatives , Ornithine/pharmacology , Peptides/pharmacology , Receptors, G-Protein-Coupled/antagonists & inhibitors , Receptors, G-Protein-Coupled/metabolism , Vasodilation/drug effects
11.
Steroids ; 96: 121-31, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25668616

ABSTRACT

The individual chemical components of commercial extract of Gymnema sylvestre, a medicinal plant used in the traditional systems of the Indian medicine for its antidiabetic and hypolipidemic properties, were isolated and evaluated for their capability to act as modulators of nuclear and membrane receptors involved in glucose and lipid homeostasis. The study disclosed for the first time that individual gymnemic acids are potent and selective antagonists for the ß isoform of LXR. Indeed the above activity was shared by the most abundant aglycone gymnemagenin (10) whereas gymnestrogenin (11) was endowed with a dual LXRα/ß antagonistic profile. Deep pharmacological investigation demonstrated that gymnestrogenin, reducing the expression of SREBP1c and ABCA1 in vitro, is able to decrease lipid accumulation in HepG2 cells. The results of this study substantiate the use of G. sylvestre extract in LXR mediated dislypidemic diseases.


Subject(s)
Drug Discovery , Gymnema sylvestre/chemistry , Orphan Nuclear Receptors/antagonists & inhibitors , Saponins/chemistry , Saponins/pharmacology , Triterpenes/chemistry , Triterpenes/pharmacology , Hep G2 Cells , Humans , Liver X Receptors , Models, Molecular , Orphan Nuclear Receptors/chemistry , Orphan Nuclear Receptors/genetics , Protein Conformation , Transcriptional Activation/drug effects
12.
J Gastroenterol ; 50(7): 707-19, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25708288

ABSTRACT

Bile acids are the end product of cholesterol metabolism. Synthesized in the liver, primary bile acids are secreted by hepatocytes and are transformed by intestinal microbiota into secondary bile acids. In addition to their role in cholesterol and lipid absorption, bile acids act as signaling molecules activating a family of nuclear and G-protein-coupled receptors collectively known as bile acid activated receptors (BARs). These receptors are expressed at high density in enterohepatic tissues, but their expression occurs throughout the body and their activation mediates regulatory functions of bile acids on lipids and glucose metabolism and immunity. In the gastrointestinal tract, BARs maintain intestinal integrity, and their deletion makes the intestine more susceptible to the damage caused by acetylsalicylic acid and nonsteroidal anti-inflammatory drugs (NSAIDs). Deficiency in farnesoid X receptor and G-protein-coupled bile acid receptor 1 genes alters the expression/activity of cystathione γ-lyase and endothelial nitric oxide synthase, two genes involved in the synthesis of hydrogen sulfide and nitric oxide, i.e., two gaseous mediators that have been shown to be essential in maintaining the intestinal homeostasis. In addition, farnesoid X receptor regulates the expression of transporters required for secretion of phospholipid by hepatocytes. Because phospholids attenuate intestinal injury caused by acetylsalicylic acid and NSAIDs, BAR agonism could be exploited to protect the intestinal mucosa against injury caused by anti-inflammatory medications. This approach might be useful in the prevention of so-called NSAID enteropathy, a common clinical condition occurring in long-term users of NSAIDs, which is not effectively prevented either by cotreatment with proton pump inhibitors or by the use of coxibs.


Subject(s)
Bile Acids and Salts/metabolism , Intestinal Mucosa/metabolism , Lipid Metabolism , Homeostasis , Humans , Signal Transduction
13.
Gastroenterology ; 148(5): 1012-1023.e14, 2015 May.
Article in English | MEDLINE | ID: mdl-25701738

ABSTRACT

BACKGROUND & AIMS: Hyperhomocysteinemia is often associated with liver and metabolic diseases. We studied nuclear receptors that mediate oscillatory control of homocysteine homeostasis in mice. METHODS: We studied mice with disruptions in Nr0b2 (called small heterodimer partner [SHP]-null mice), betaine-homocysteine S-methyltransferase (Bhmt), or both genes (BHMT-null/SHP-null mice), along with mice with wild-type copies of these genes (controls). Hyperhomocysteinemia was induced by feeding mice alcohol (National Institute on Alcohol Abuse and Alcoholism binge model) or chow diets along with water containing 0.18% DL-homocysteine. Some mice were placed on diets containing cholic acid (1%) or cholestyramine (2%) or high-fat diets (60%). Serum and livers were collected during a 24-hour light-dark cycle and analyzed by RNA-seq, metabolomic, and quantitative polymerase chain reaction, immunoblot, and chromatin immunoprecipitation assays. RESULTS: SHP-null mice had altered timing in expression of genes that regulate homocysteine metabolism compared with control mice. Oscillatory production of S-adenosylmethionine, betaine, choline, phosphocholine, glyceophosphocholine, cystathionine, cysteine, hydrogen sulfide, glutathione disulfide, and glutathione, differed between SHP-null mice and control mice. SHP inhibited transcriptional activation of Bhmt and cystathionine γ-lyase by FOXA1. Expression of Bhmt and cystathionine γ-lyase was decreased when mice were fed cholic acid but increased when they were placed on diets containing cholestyramine or high-fat content. Diets containing ethanol or homocysteine induced hyperhomocysteinemia and glucose intolerance in control, but not SHP-null, mice. In BHMT-null and BHMT-null/SHP-null mice fed a control liquid, lipid vacuoles were observed in livers. Ethanol feeding induced accumulation of macrovesicular lipid vacuoles to the greatest extent in BHMT-null and BHMT-null/SHP-null mice. CONCLUSIONS: Disruption of Shp in mice alters timing of expression of genes that regulate homocysteine metabolism and the liver responses to ethanol and homocysteine. SHP inhibits the transcriptional activation of Bhmt and cystathionine γ-lyase by FOXA1.


Subject(s)
Circadian Rhythm , Hepatocyte Nuclear Factor 3-alpha/metabolism , Homocysteine/metabolism , Hyperhomocysteinemia/metabolism , Liver/metabolism , Receptors, Cytoplasmic and Nuclear/metabolism , Animals , Betaine-Homocysteine S-Methyltransferase/genetics , Betaine-Homocysteine S-Methyltransferase/metabolism , Blood Glucose/metabolism , Cholestyramine Resin , Cholic Acid , Cystathionine gamma-Lyase/genetics , Cystathionine gamma-Lyase/metabolism , Diet, High-Fat , Disease Models, Animal , Ethanol , Gene Expression Regulation, Enzymologic , Glucose Intolerance/blood , Glucose Intolerance/metabolism , Homeostasis , Homocysteine/blood , Hyperhomocysteinemia/blood , Hyperhomocysteinemia/chemically induced , Hyperhomocysteinemia/genetics , Hyperhomocysteinemia/prevention & control , Mice, Knockout , RNA, Messenger/metabolism , Receptors, Cytoplasmic and Nuclear/deficiency , Receptors, Cytoplasmic and Nuclear/genetics , Time Factors , Transcriptional Activation
14.
J Med Chem ; 57(20): 8477-95, 2014 Oct 23.
Article in English | MEDLINE | ID: mdl-25247751

ABSTRACT

Nuclear and G-protein coupled receptors are considered major targets for drug discovery. FXR and GP-BAR1, two bile acid-activated receptors, have gained increasing consideration as druggable receptors. Because endogenous bile acids often target both receptor families, the development of selective ligands has been proven difficult, exposing patients to side effects linked to an unwanted activation of one of the two receptors. In the present study, we describe a novel library of semisynthetic bile acid derivatives obtained by modifications on the cholane scaffold. The pharmacological characterization of this library led to the discovery of 7α-hydroxy-5ß-cholan-24-sulfate (7), 6ß-ethyl-3α,7ß-dihydroxy-5ß-cholan-24-ol (EUDCOH, 26), and 6α-ethyl-3α, 7α-dihydroxy-24-nor-5ß-cholan-23-ol (NorECDCOH, 30) as novel ligands for FXR and GP-BAR1 that might hold utility in the treatment of FXR and GP-BAR1 mediated disorders.


Subject(s)
Bile Acids and Salts/chemistry , Cholanes/chemistry , Receptors, Cytoplasmic and Nuclear/metabolism , Receptors, G-Protein-Coupled/metabolism , Small Molecule Libraries/pharmacology , Animals , Chemistry Techniques, Synthetic , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical/methods , HEK293 Cells/drug effects , Hep G2 Cells/drug effects , Humans , Ligands , Male , Mice, Inbred C57BL , Mice, Mutant Strains , Molecular Targeted Therapy , Pruritus/drug therapy , Receptors, Cytoplasmic and Nuclear/genetics , Receptors, G-Protein-Coupled/genetics , Small Molecule Libraries/chemistry , Structure-Activity Relationship
15.
PLoS One ; 9(9): e106503, 2014.
Article in English | MEDLINE | ID: mdl-25202975

ABSTRACT

The intestinal microbiota is increasingly recognized as a complex signaling network that impacts on many systems beyond the enteric system modulating, among others, cognitive functions including learning, memory and decision-making processes. This has led to the concept of a microbiota-driven gut-brain axis, reflecting a bidirectional interaction between the central nervous system and the intestine. A deficit in synaptic plasticity is one of the many changes that occurs with age. Specifically, the archetypal model of plasticity, long-term potentiation (LTP), is reduced in hippocampus of middle-aged and aged rats. Because the intestinal microbiota might change with age, we have investigated whether the age-related deficit in LTP might be attenuated by changing the composition of intestinal microbiota with VSL#3, a probiotic mixture comprising 8 Gram-positive bacterial strains. Here, we report that treatment of aged rats with VSL#3 induced a robust change in the composition of intestinal microbiota with an increase in the abundance of Actinobacteria and Bacterioidetes, which was reduced in control-treated aged rats. VSL#3 administration modulated the expression of a large group of genes in brain tissue as assessed by whole gene expression, with evidence of a change in genes that impact on inflammatory and neuronal plasticity processes. The age-related deficit in LTP was attenuated in VSL#3-treated aged rats and this was accompanied by a modest decrease in markers of microglial activation and an increase in expression of BDNF and synapsin. The data support the notion that intestinal microbiota can be manipulated to positively impact on neuronal function.


Subject(s)
Aging/physiology , Brain/drug effects , Intestines/microbiology , Long-Term Potentiation/drug effects , Microbiota/drug effects , Probiotics/pharmacology , Transcriptome/drug effects , Aging/drug effects , Animals , Biomarkers/metabolism , Brain/cytology , Brain/metabolism , Brain/physiology , Hippocampus/cytology , Hippocampus/drug effects , Hippocampus/metabolism , Hippocampus/physiology , Male , Neurons/drug effects , Rats , Rats, Wistar
16.
J Med Chem ; 57(18): 7687-701, 2014 Sep 25.
Article in English | MEDLINE | ID: mdl-25162837

ABSTRACT

Bile acids are signaling molecules interacting with the nuclear receptor FXR and the G-protein coupled receptor 1 (GP-BAR1/TGR5). GP-BAR1 is a promising pharmacological target for the treatment of steatohepatitis, type 2 diabetes, and obesity. Endogenous bile acids and currently available semisynthetic bile acids are poorly selective toward GP-BAR1 and FXR. Thus, in the present study we have investigated around the structure of UDCA, a clinically used bile acid devoid of FXR agonist activity, to develop a large family of side chain modified 3α,7ß-dihydroxyl cholanoids that selectively activate GP-BAR1. In vivo and in vitro pharmacological evaluation demonstrated that administration of compound 16 selectively increases the expression of pro-glucagon 1, a GP-BAR1 target, in the small intestine, while it had no effect on FXR target genes in the liver. Further, compound 16 results in a significant reshaping of bile acid pool in a rodent model of cholestasis. These data demonstrate that UDCA is a useful scaffold to generate novel and selective steroidal ligands for GP-BAR1.


Subject(s)
Drug Discovery , Receptors, G-Protein-Coupled/agonists , Ursodeoxycholic Acid/analogs & derivatives , Ursodeoxycholic Acid/pharmacology , HEK293 Cells , Hep G2 Cells , Humans , Models, Molecular , Protein Conformation , Receptors, G-Protein-Coupled/chemistry , Substrate Specificity
17.
Mar Drugs ; 12(6): 3091-115, 2014 May 27.
Article in English | MEDLINE | ID: mdl-24871460

ABSTRACT

In recent years many sterols with unusual structures and promising biological profiles have been identified from marine sources. Here we report the isolation of a series of 24-alkylated-hydroxysteroids from the soft coral Sinularia kavarattiensis, acting as pregnane X receptor (PXR) modulators. Starting from this scaffold a number of derivatives were prepared and evaluated for their ability to activate the PXR by assessing transactivation and quantifying gene expression. Our study reveals that ergost-5-en-3ß-ol (4) induces PXR transactivation in HepG2 cells and stimulates the expression of the PXR target gene CYP3A4. To shed light on the molecular basis of the interaction between these ligands and PXR, we investigated, through docking simulations, the binding mechanism of the most potent compound of the series, 4, to the PXR. Our findings provide useful functional and structural information to guide further investigations and drug design.


Subject(s)
Anthozoa/chemistry , Hydroxysteroids/pharmacology , Receptors, Steroid/drug effects , Animals , Cytochrome P-450 CYP3A/genetics , Gene Expression Regulation/drug effects , Hep G2 Cells , Humans , Hydroxysteroids/chemistry , Hydroxysteroids/isolation & purification , Ligands , Molecular Docking Simulation , Pregnane X Receptor , Receptors, Steroid/metabolism
18.
PLoS One ; 9(4): e94798, 2014.
Article in English | MEDLINE | ID: mdl-24736615

ABSTRACT

BACKGROUND: The human immunodeficiency virus type 1 (HIV-1) p17 is a matrix protein involved in virus life's cycle. CXCR2 and Syndecan-2, the two major coreceptors for the p17 protein, are expressed in hepatic stellate cells (HSCs), a key cell type involved in matrix deposition in liver fibrotic disorders. AIM: In this report we have investigated the in vitro impact of p17 on HSCs transdifferentiation and function and underlying signaling pathways involved in these processes. METHODS: LX-2 cells, a human HSC line, and primary HSC were challenged with p17 and expressions of fibrogenic markers and of p17 receptors were assessed by qRT-PCR and Western blot. Downstream intracellular signaling pathways were evaluated with qRT-PCR and Western blot as well as after pre-treatment with specific pathway inhibitors. RESULTS: Exposure of LX2 cells to p17 increases their contractile force, reshapes the cytoskeleton fibers and upregulates the expression of transdifferentiation markers including αSMA, COL1α1 and endothelin-1 through the activation of Jak/STAT and Rho signaling pathways. These effects are lost in HSCs pre-incubated with a serum from HIV positive person who underwent a vaccination with a p17 peptide. Confocal laser microscopy studies demonstrates that CXCR2 and syndecan-2 co-associate at the plasma membrane after exposure to p17. Immunostaining of HIV/HCV liver biopsies from co-infected patients reveals that the progression of liver fibrosis correlates with a reduced expression of CXCR2. CONCLUSIONS: The HIV matrix protein p17 is pro-fibrogenic through its interactions both with CXCR2 and syndecan-2 on activated HSCs.


Subject(s)
HIV Antigens/metabolism , HIV-1/metabolism , Hepatic Stellate Cells/cytology , Hepatic Stellate Cells/metabolism , Receptors, Interleukin-8B/metabolism , Syndecan-2/metabolism , gag Gene Products, Human Immunodeficiency Virus/metabolism , Actins/metabolism , Adult , Aged , Antibodies, Viral/immunology , Cell Line , Collagen Type I/metabolism , Cytoskeleton/drug effects , Cytoskeleton/metabolism , Disease Progression , Endothelin-1/metabolism , Female , Gene Expression Regulation/drug effects , HIV Antigens/pharmacology , HIV-1/immunology , HIV-1/physiology , Hepatic Stellate Cells/drug effects , Humans , Liver Cirrhosis/pathology , Liver Cirrhosis/virology , Male , Middle Aged , Protein Binding , Protein Transport , Receptors, Interleukin-8/metabolism , Signal Transduction/drug effects , Vaccination , gag Gene Products, Human Immunodeficiency Virus/pharmacology , rho GTP-Binding Proteins/metabolism , rho-Associated Kinases/metabolism
19.
Steroids ; 83: 80-5, 2014 May.
Article in English | MEDLINE | ID: mdl-24582706

ABSTRACT

During the chromatographic purification of organic extracts obtained from Plakortis cfr. lita we obtained three highly degraded steroid derivatives, the known incisterol A2 (1) and the new incisterols A5 (2) and A6 (3). The new compounds were characterized basing on NMR and MS evidences along with comparison with model compounds. Incisterol A5 proved to bear a 17S-ethyl-15E,18-diene (incisterol numbering system) side chain, found for the first time in a marine organism. The new incisterols A5 and A6 proved to be potent inducers of transactivation of the pregnane X receptor (PXR) and they also stimulate the expression of CYP7A4 and MDR1 with a potency comparable to that of Rifaximin. These observations prompt to consider incisterols A5 and A6 as new potent agonists of PXR. On the other hand, the 17R-methyl analogue incisterol A2 shows only a poor PXR agonist activity. Molecular docking simulations elucidated the binding mechanism of the active incisterols in the ligand binding domain of PXR.


Subject(s)
Aquatic Organisms/chemistry , Receptors, Steroid/agonists , Sterols/chemistry , Sterols/metabolism , Gene Expression Regulation , Hep G2 Cells , Humans , Magnetic Resonance Spectroscopy , Models, Molecular , Pregnane X Receptor , Real-Time Polymerase Chain Reaction , Transcriptional Activation
20.
J Med Chem ; 57(3): 937-54, 2014 Feb 13.
Article in English | MEDLINE | ID: mdl-24387325

ABSTRACT

Bile acids exert genomic and nongenomic effects by interacting with membrane G-protein-coupled receptors, including the bile acid receptor GP-BAR1, and nuclear receptors, such as the farnesoid X receptor (FXR). These receptors regulate overlapping metabolic functions; thus, GP-BAR1/FXR dual agonists, by enhancing the biological response, represent an innovative strategy for the treatment of enteroendocrine disorders. Here, we report the design, total synthesis, and in vitro/in vivo pharmacological evaluation of a new generation of dual bile acid receptor agonists, with the most potent compound, 19, showing promising pharmacological profiles. We show that compound 19 activates GP-BAR1, FXR, and FXR regulated genes in the liver, increases the intracellular concentration of cAMP, and stimulates the release of the potent insulinotropic hormone GLP-1, resulting in a promising drug candidate for the treatment of metabolic disorders. We also elucidate the binding mode of the most potent dual agonists in the two receptors through a series of computations providing the molecular basis for dual GP-BAR1/FXR agonism.


Subject(s)
Cholanes/chemical synthesis , Hypoglycemic Agents/chemical synthesis , Receptors, Cytoplasmic and Nuclear/agonists , Receptors, G-Protein-Coupled/agonists , Cholanes/chemistry , Cholanes/pharmacology , Drug Design , HEK293 Cells , Humans , Hypoglycemic Agents/chemistry , Hypoglycemic Agents/pharmacology , Molecular Docking Simulation , Protein Binding , Receptors, Cytoplasmic and Nuclear/chemistry , Receptors, G-Protein-Coupled/chemistry , Stereoisomerism , Structure-Activity Relationship , Transcriptional Activation
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