Development of polymorphic markers in the immune gene complex loci of cattle.

The addition of cattle health and immunity traits to genomic selection indices holds promise to increase individual animal longevity and productivity, and decrease economic losses from disease. However, highly variable genomic loci that contain multiple immune-related genes were poorly assembled in the first iterations of the cattle reference genome assembly and underrepresented during the development of most commercial genotyping platforms. As a consequence, there is a paucity of genetic markers within these loci that may track haplotypes related to disease susceptibility. By using hierarchical assembly of bacterial artificial chromosome inserts spanning 3 of these immune-related gene regions, we were able to assemble multiple full-length haplotypes of the major histocompatibility complex, the leukocyte receptor complex, and the natural killer cell complex. Using these new assemblies and the recently released ARS-UCD1.2 reference, we aligned whole-genome shotgun reads from 125 sequenced Holstein bulls to discover candidate variants for genetic marker development. We selected 124 SNPs, using heuristic and statistical models to develop a custom genotyping panel. In a proof-of-principle study, we used this custom panel to genotype 1,797 Holstein cows exposed to bovine tuberculosis (bTB) that were the subject of a previous GWAS study using the Illumina BovineHD array. Although we did not identify any significant association of bTB phenotypes with these new genetic markers, 2 markers exhibited substantial effects on bTB phenotypic prediction. The models and parameters trained in this study serve as a guide for future marker discovery surveys particularly in previously unassembled regions of the cattle genome.

Azole derivatives as histamine H3 receptor antagonists, part 2: C-C and C-S coupled heterocycles.

With a small series of compounds we demonstrated the variability in the core region of the human histamine H(3) receptor (hH(3)R) antagonist structural blueprint by introducing polar azole groups (oxazole, oxadiazole, thiazole and triazole). Additional variations achieved by coupling different residues to the heterocyclic core structure led to further optimisation of in vitro receptor binding of the novel azole derivatives.

Azole derivatives as histamine H3 receptor antagonists, part I: thiazol-2-yl ethers.

Most human histamine H(3) receptor (hH(3)R) antagonists follow a general structural blueprint, containing a basic moiety linked by a spacer to a substituted core element. In this investigation the acceptance of thiazol-2-yl ether moieties in the core region is proved with some ether derivatives showing hH(3)R binding affinities in the nanomolar concentration range. A diversity of structural motifs is used as substituents to enhance the in vitro hH(3)R binding affinity.

Synthesis and evaluation of amides surrogates of dopamine D3 receptor ligands.

Isosteric replacement of the amide function and modulation of the arylpiperazine moiety of known dopamine D3 receptor ligands led to potent and selective compounds. Enhanced bioavailability and preferential brain distribution make compound 6c a good candidate for pharmacological and clinical evaluation.

Structure of murine CTLA-4 and its role in modulating T cell responsiveness.

The effective regulation of T cell responses is dependent on opposing signals transmitted through two related cell-surface receptors, CD28 and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4). Dimerization of CTLA-4 is required for the formation of high-avidity complexes with B7 ligands and for transmission of signals that attenuate T cell activation. We determined the crystal structure of the extracellular portion of CTLA-4 to 2.0 angstrom resolution. CTLA-4 belongs to the immunoglobulin superfamily and displays a strand topology similar to Valpha domains, with an unusual mode of dimerization that places the B7 binding sites distal to the dimerization interface. This organization allows each CTLA-4 dimer to bind two bivalent B7 molecules and suggests that a periodic arrangement of these components within the immunological synapse may contribute to the regulation of T cell responsiveness.

Widespread distribution of brain dopamine receptors evidenced with [125I]iodosulpride, a highly selective ligand.

The new benzamide derivative [125I]iodosulpride is a highly sensitive and selective ligand for D-2 dopamine receptors and displays a very low nonspecific binding to membrane or autoradiographic sections. On autoradiographic images, D-2 receptors are present not only in well-established dopaminergic areas but also, in a discrete manner, in a number of catecholaminergic regions in which the dopaminergic innervation is still unknown, imprecise, or controversial, as in the sensorimotor cerebral cortex or cerebellum. This widespread distribution suggests larger physiological and pathophysiological roles for cerebral dopamine receptors than was previously thought.

Selective protection of methionine enkephalin released from brain slices by enkephalinase inhibition.

Methionine enkephalin release was evoked by depolarization of slices from rat striatum with potassium. In the presence of 0.1 microM thiorphan [(N(R,S)-3-mercapto-2-benzylpropionyl)glycine], a potent inhibitor of enkephalin dipeptidyl carboxypeptidase (enkephalinase), the recovery of the pentapeptide in the incubation medium was increased by about 100 percent. A similar effect was observed with the dipeptide phenylalanylalanine, a selective although less potent enkephalinase inhibitor. Inhibition of other known enkephalin-hydrolyzing enzymes--aminopeptidase by 0.1 mM puromycin or angiotensin-converting enzyme by 1 microM captopril--did not significantly enhance the recovery of released methionine enkephalin. These data indicate that enkephalinase is critically involved in the inactivation of the endogenous opioid peptide released from striatal neurons.

Fluorinated non-imidazole histamine H3 receptor antagonists.

Fluorine substituents have become a widespread and important component in drug design and development. Here, the synthesis of fluorine containing compounds and some corresponding precursor molecules are presented for potential isotope labelling as well as their data obtained with in vitro and in vivo screenings. The compounds vary in the basic centres (piperidine or pyrrolidine) and are fluoro substituted in different positions of the basic alicyclic moiety. Pharmacological evaluation resulted in ligands with high affinities at hH(3) receptor in the nanomolar and subnanomolar concentration range and some with high antagonist in vivo potencies.

The major histocompatibility complex homozygous inbred Babraham pig as a resource for veterinary and translational medicine.

The Babraham pig is a highly inbred breed first developed in the United Kingdom approximately 50 years ago. Previous reports indicate a very high degree of homozygosity across the genome, including the major histocompatibility complex (MHC) region, but confirmation of homozygosity at the specific MHC loci was lacking. Using both direct sequencing and PCR-based sequence-specific typing, we confirm that Babraham pigs are essentially homozygous at their MHC loci and formalise their MHC haplotype as Hp-55.6. This enhances the utility of the Babraham pig as a useful biomedical model for studies in which controlling for genetic variation is important.

Dopamine D3 receptors expressed by all mesencephalic dopamine neurons.

A polyclonal antibody was generated using synthetic peptides designed in a specific sequence of the rat D(3) receptor (D(3)R). Using transfected cells expressing recombinant D(3)R, but not D(2) receptor, this antibody labeled 45-80 kDa species in Western blot analysis, immunoprecipitated a soluble fraction of [(125)I]iodosulpride binding, and generated immunofluorescence, mainly in the cytoplasmic perinuclear region of the cells. In rat brain, the distribution of immunoreactivity matched that of D(3)R binding, revealed using [(125)I]R(+)trans-7-hydroxy-2-[N-propyl-N-(3'-iodo-2'-propenyl)amino] tetralin ([(125)I]7-trans-OH-PIPAT), with dense signals in the islands of Calleja and mammillary bodies, and moderate to low signals in the shell of nucleus accumbens (AccSh), frontoparietal cortex, substantia nigra (SN), ventral tegmental area (VTA) and lobules 9 and 10 of the cerebellum. Very low or no signals could be detected in other rat brain regions, including dorsal striatum, or in D(3)R-deficient mouse brain. Labeling of perikarya of AccSh and SN/VTA appeared with a characteristic punctuate distribution, mostly at the plasma membrane where it was not associated with synaptic boutons, as revealed by synaptophysin immunoreactivity. In SN/VTA, D(3)R immunoreactivity was found on afferent terminals, arising from AccSh, in which destruction of intrinsic neurons by kainate infusions produced a loss of D(3)R binding in both AccSh and SN/VTA. D(3)R-immunoreactivity was also found in all tyrosine hydroxylase (TH)-positive neurons observed in SN, VTA and A8 retrorubral fields, where it could represent D(3) autoreceptors controlling dopamine neuron activities, in agreement with the elevated dopamine extracellular levels in projection areas of these neurons found in D(3)R-deficient mice.

Novel dopamine receptors half a decade later.

Only half a decade ago, the effects of dopamine were all attributed to activation of two receptor subtypes, the D1 and D2, with opposing effects on adenylate cyclase, and for which apparently selective ligands were available. From the end of 1988, however, the application of homology cloning techniques starting from sequences of the seven transmembrane domain catecholamine receptors, particularly that of the D2 receptor, led to the identification of 'novel', previously uncharacterized dopamine receptors. In this article, Pierre Sokoloff and Jean-Charles Schwartz discuss the functional significance of such diversity, as well as the new therapeutic perspectives it offers.

Expression analysis of the histamine H(3) receptor in developing rat tissues.

Endogenous histamine is involved in tissue growth and cell proliferation. In accordance with a putative function of the H(3) receptor in this mitogenic effect, we show that H(3)-receptor mRNAs are expressed together with those of the histamine-synthesizing enzyme in the embryonic liver and adipose tissue, and in various epithelia. Finally, we show that activation of recombinant H(3) receptors enhances MAP kinase activity.

Search for histamine H3 receptor antagonists with combined inhibitory potency at Ntau-methyltransferase: ether derivatives.

With the recent development of new hybrid compounds having histamine H3 receptor antagonist with combined histamine Ntau-methyltransferase (HMT) inhibitory potency an innovative approach was described in the research of novel lead compounds modulating histaminergic neurotransmission. Several compounds containing an ether moiety derived from the recently published 4-(3-piperidinopropoxy)phenylaminoquinoline derivatives (like FUB 836), were synthesized in this study and tested for their affinity at cloned human histamine H3 (hH3) receptors and on the inhibition of rat HMT. Besides different heterocycles, e.g. nitro- or amino-substituted pyridines, quinolines, benzothiazole or pyrroline, three classes of compounds were produced: heteroaromatic 3-piperidinopropyl ethers, keto- or imino-substituted 4-(3-piperidinopropyl)phenyl ethers and 4-(3-piperidinopropyl)phenyl ethers with substituted (alkyl)aminopyridines. Whereas the (3-piperidinopropoxy)heterocycles showed only moderate activities on both test models, the 4-(3-piperidinopropoxy)phenyl derivatives were identified as potent histamine H3 receptor ligands and/or HMT inhibitors. Ki values up to 0.42 nM were found for the affinity to the hH3 receptor. HMT inhibitory potency was identified with IC50 values about 0.3 microM for the most potent compounds in this series. Comparison of the pyridine-containing derivatives to recently published quinoline analogues showed a decrease in potencies for the pyridines. The dual activity, H3 receptor affinity and HMT inhibition, was moderate to good. For all compounds affinities at hH3 receptors were higher than their inhibitory HMT potencies. The described new histamine H3 receptor antagonists with an ether moiety represent a further promising step in our investigations for a dual activity.

Effect of long-term therapy with fasidotril, a mixed inhibitor of neprilysin and angiotensin-converting enzyme (ACE), on survival of rats after myocardial infarction.

OBJECTIVE: Two hormonal systems with opposite effects are activated in congestive heart failure: the renin-angiotensin system that promotes vasoconstriction, cardiac hypertrophy and salt retention, and the atrial natriuretic factor (ANF), which has vasorelaxant and natriuretic effects. It could be of therapeutic interest to associate prevention of angiotensin II formation, by inhibition of angiotensin I-converting enzyme (ACE), with potentiation of the ANF effects, by inhibition of neprilysin (NEP). METHODS: The effects of long-term therapy with fasidotril, a mixed NEP/ACE inhibitor, were assessed in rats submitted to coronary artery ligation. Twenty-four hours after ligation, 172 rats were assigned to either placebo or fasidotril therapy (180 mg/kg/day, orally) for 40 weeks. The date of spontaneous death was recorded, myocardial infarct size was determined and rats were classified as having small, moderate or large infarcts. RESULTS: In rats with moderate infarcts, fasidotril prolonged survival, 50% of the control rats dying during the 40-week observation period compared with 30% of treated rats (P = 0.04, log-rank test)). In rats with large infarcts, mortality was significantly reduced during the initial 25 weeks of therapy, during which 23.5% of animals died compared to 53.8% in untreated rats (P = 0.015). Cardiac hypertrophy was significantly attenuated by fasidotril for the three infarct sizes. Plasma renin activity was not increased by therapy, which presumably reflected the inhibition of renal renin secretion by endogenous ANF. Fasidotril therapy had no significant effects on arterial blood pressure and heart rate. CONCLUSION: In addition to its beneficial effects on survival and cardiac hypertrophy, the lack of hypotensive effect of fasidotril is of interest by reducing the risk of renal hypoperfusion and differentiates the mixed inhibitor from selective ACE inhibitors.

Effect of sinorphan, an enkephalinase inhibitor, on plasma atrial natriuretic factor and sodium urinary excretion in cirrhotic patients with ascites.

We examined the acute effects of sinorphan, an inhibitor of enkephalinase, on plasma atrial natriuretic factor (ANF) and urinary sodium excretion in cirrhotic patients with ascites. A single oral dose of sinorphan (100 or 30 mg in 11 and 5 patients, respectively) was administered against placebo according to a double blind cross-over protocol. Basal plasma ANF levels varied over a large range between 2.6-79 pmol/L. Sinorphan, at a dose of 100 mg, inhibited 70% of plasma enkephalinase activity 60 min after ingestion and elicited simultaneously an increase in plasma ANF and cGMP levels 1.8 and 1.5 times basal values, respectively. There was a transient increase in sodium urinary output without a change in creatinine clearance over the initial 2-h period following drug administration. An increase in urinary cGMP was also observed on a longer period of 6 h. Plasma aldosterone decreased significantly, but the lowest concentration was reached 1 h later than the peak of plasma ANF. Mean blood pressure and PRA were unmodified. The effects of 30 mg sinorphan on plasma ANF, cGMP, and aldosterone were also significant, but less marked than those of the higher dose. Therefore, enkephalinase inhibition transiently increases sodium urinary excretion in cirrhotic patients with ascites via a mechanism that is likely to imply reduction of ANF catabolism. These results suggest that ANF could play a role in the control of sodium homeostasis in liver cirrhosis with ascites.

Lack of association between anorexia nervosa and D3 dopamine receptor gene.

BACKGROUND: Evidence from family and twin studies suggests a genetic contribution to the etiology of anorexia nervosa. Different genes could contribute to the vulnerability to anorexia nervosa, but dopamine could be more specifically implicated in anorexia nervosa because of pharmacologic, endocrine, and neurobiological specificities. The dopamine receptor D3 (DRD3) may be of additional interest, since it is specifically located in the limbic area, an area implicated in reward and reinforcement behavior. METHODS: We performed an association study between 39 patients with severe (requiring hospitalization and with young age at onset) anorexia nervosa (DSM-III-R), and 42 controls, with the Bal I polymorphism in exon I of the DRD3 gene. RESULTS: There was no significant difference between patients with anorexia nervosa and controls in allele frequencies or genotype count. The association was still negative between subgroups separated according to family history of anorexia nervosa or comorbid mood disorders. CONCLUSIONS: Despite the fact that the number of patients tested is small, there is good evidence that the Bal I DRD3 polymorphism does not play a major role in the genetic component of anorexia nervosa. It would be useful to test polymorphisms of the other genes coding for dopamine receptors.

Dopamine-related genes and their relationships to monoamine metabolites in CSF.

Monoamine metabolite (MM) levels in lumbar cerebrospinal fluid (CSF) are extensively used as indirect estimates of monoamine turnover in the brain. In this study we investigated genotypes for DNA polymorphisms in the D2 (DRD2), D3 (DRD3), and D4 (DRD4) dopamine receptor and tyrosine hydroxylase (TH) genes and their relationships to CSF MM in healthy volunteers (n = 66). Concentrations of homovanillic acid (HVA), 3-methoxy-4-hydroxyphenylglycol (MHPG), and 5-hydroxyindoleacetic acid (5-HIAA) were corrected for back length, a confounding variable. Corrected MM levels were not related to age, gender, height, weight heredity, season or atmospheric pressure at sampling. Individuals with specific DRD2 and TH allele and genotype configurations significantly differed in HVA and MHPG concentrations. DRD3 homo- and heterozygotic genotypes had significantly different CSF 5-HIAA levels. DRD4 genotypes were not related to MM concentrations. The results suggest that specific DRD2, DRD3, and TH genotypes participate in the regulation of monoamine turnover in the central nervous system. Accordingly monoamine receptors and synthesizing enzyme genotypes appear to be variance factors influencing MM concentrations in CSF. The relationships found in this study support MM concentrations as markers for monoamine transmission in the human brain.

Comparison of acetorphan with clonidine for opiate withdrawal symptoms.

OBJECTIVE AND METHOD: The authors compared the effects of acetorphan, an enkephalinase inhibitor, with those of clonidine for the treatment of the opioid withdrawal syndrome. Nineteen patients addicted to heroin or synthetic opiates who were undergoing drug withdrawal and displayed a withdrawal syndrome according to DSM-III criteria were studied for 5 days in a hospital setting. In a double-blind trial, 10 subjects were given acetorphan intravenously and nine were given clonidine; objective signs and subjective symptoms of withdrawal were recorded. RESULTS: On several objective signs, the effect of acetorphan was more marked than that of clonidine, whereas the two drugs exhibited similar efficacy with respect to the subjective components of withdrawal. No side effect was noted in the subjects who received acetorphan. CONCLUSIONS: Enkephalinase inhibition may constitute a novel and safe therapeutic approach to the opioid withdrawal syndrome.

Apparent identity of cerebral tyrosylsulfotransferase activities using either a cholecystokinin derivative or an acidic amino acid polymer as substrate.

The tyrosylsulfotransferase activities of rat cerebral fractions transferring [35S]sulfate groups from 3'-phosphoadenosine 5'-[35S]phosphosulfate to either Boc-cholecystokinin-8 (in non-sulfated form) or the acidic amino acid polymer (Glu, Ala, Tyr)n (6:3:1) were compared. They appear similar regarding subcellular distribution (both being enriched in the microsomal fraction) and inhibition by an excess of the acidic amino acid polymer, NaCl or 2,6-dichloro 4-nitrophenol. These results obtained with artificial substrates suggest that identical (or closely similar) tyrosylsulfotransferases are responsible for sulfation of tyrosine residues of several secretory proteins from various tissues.

Detection of the tripeptide Tyr-Gly-Gly, a putative enkephalin metabolite in brain, using a sensitive radioimmunoassay.

A sensitive and specific radioimmunoassay has been developed for YGG. The tripeptide was previously derivatised with p-benzoquinone to prepare the immunogen and the 125I tracer as well as in samples submitted to the RIA. The sensitivity is about 1 nM as compared with 8000 nM for underivatised YGG. Measurable amounts of endogenous YGG immunoreactivity, co-eluting in HPLC with authentic YGG, were detected in mouse striatal extracts.