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The alpha(v)beta(3) integrin is an adhesion molecule involved in physiological and pathological angiogenesis as well as in tumor invasion and metastasis, and therefore, there is a strong interest in developing novel agents interacting with this molecule. We report the synthesis and characterization of fluorescent alpha(v)beta(3) integrin probes and their use to visualize integrin alpha(v)beta(3) expression on human normal and cancer cells, The fluorescent probes we describe here may be of use for noninvasive imaging of alpha(v)beta(3) integrin expression also hi vivo.

The specificity of SEL1L expression and promoter activity for the pancreatic cell population, its chromosomal location, as well as its similarities to the yeast Hrd3p protein, a component of HRD complex which is responsible for endoplasmic reticulum (ER)-associated degradation of numerous ER-resident proteins, prompted us to study its effects on beta cell function. In this study we show that lowering SEL1L expression, by using the short interfering RNAs technology as well as antisense transfection, resulted in severe perturbation of betaTC-3 growth and metabolic activity. We hypothesize that SEL1L may exert its function by protecting the cells from ER stress and could counteract immune responses.

CTLA4 protein is a receptor molecule that plays a critical role as a negative regulator of the immune response. Therefore, genetic variations in CTLA4 may confer susceptibility to autoimmune diseases such as multiple sclerosis (MS). In order to investigate the association of two CTLA4 polymorphisms (+49 A/G and -318 C/T) with multiple sclerosis, sporadic MS patients and healthy controls from Italy were genotyped through direct DNA sequencing. Considering single-loci variations, no differences in the allelic and genotypic frequencies between patients and controls were found. However, considering a putative interaction at the two loci, the T/G combination was more frequently observed in patients than in controls. This result suggests that this allelic combination of the CTLA4 polymorphisms may be involved in the susceptibility to MS in the Italian population.

Cyclic RGD-containing functionalized azabicycloalkane peptides were synthesized with the aim of developing high-affinity selective integrin ligands as carriers for therapeutic and diagnostic purposes. Herein we describe the synthesis and in vitro screening of these RGD derivatives, as well as the determination of their conformational properties in solution by spectroscopic and computational methods. Docking studies with the X-ray crystal structure of the extracellular domain of integrin alpha(v)beta(3) were also performed to elucidate the structural binding requirements and to rationalize the biological results. One compound in particular was found to be the best alpha(v)beta(3) integrin binder (IC(50)=53.7 nM) among the new functionalized RGD cyclic peptides, thus emerging as a promising candidate for covalent bonding and selective homing of useful functional units.

SEL1L, a human gene located on chromosome 14q24.3–q31, is highly expressed in adult pancreas. It is proximal to D14S67 (IDDM11) a proposed type I diabetes susceptibility locus. Considering the organ specific expression of SEL1L, a fundamental role of SEL1L in pancreatic growth can be hypothesized. While screening for mutations in young diabetic patients, in children affected by persistent hyperinsulinemic hypoglycemia of infancy (PHHI), in patients with non-functional endocrine tumours and in over 100 control subjects, we identified a novel polymorphism (D162G) residing on the fourth exon of the gene. This exon encodes for the fibronectin type II domain and the nucleotide change involves a highly conserved amino acid. The D162G polymorphism induces a major change in the amino acid composition producing a possible disruptive role in collagen binding.

For a reappraisal of the current perplexing notion that the small intestine of the rat lacks in vitro opiate receptor binding, crude microsomal fractions were prepared from longitudinal muscle with attached myenteric plexus, isolated from rat small intestine, carefully dissected free from the mesentery. These preparations, when incubated with the potent opiate etorphine, tritium labelled at high specific activity (31 Ci/mmole), exhibited high affinity (K D = 1.2 nM) saturable binding. This in vitro binding of 3 H-etorphine (2×10 −9 M) was stereospecific, since it was completely prevented by 1×10 −6 M levorphanol and unaffected by the same concentration of dextrorphan. When 10 mM NaCl was added, considerably less naloxone was required than in control medium for inhibiting the binding of tritiated etorphine to the rat small intestine longitudinal muscle microsomal preparation. Our present evidence for substantial in vitro opiate receptor binding in the rat small intestine agrees with previous results of pharmacological and in vivo binding studies supporting the existence of specific sites of action for narcotics therein.

Scatchard analysis of 3H-dihydromorphine (3H-DHM) binding to rat brain subcellular fractions gave a curvilinear plot in the microsomal (P3) and a linear plot in the mitochondrial (P2) fraction, respectively. In contrast, plots of 3H-ethylketocyclazocine (3H-EK) binding were linear in the P3 and curvilinear in the P2 fraction. No differences were seen in the potency of morphine and ketazocine in displacing either 3H-DHM or 3H-EK in the P2 fraction. In the P3 fraction, however, morphine was more potent than ketazocine in displacing 3H-DHM, but the reverse was true when 3H-EK was used as the ligand. Isolation of the P3 fraction may facilitate the demonstration of a kappa receptor in the rat brain.

The rat mesentery was found to contain an interfering material responsible for failure to detect in vitro opiate receptor binding in preparations from rat small intestine longitudinal muscle. A crude microsomal fraction obtained from the mesentery, after dilution so as to deliver 8 μg protein per sample, was still capable of producing substantial inhibition (50%) of 0.4 nM 3H-etorphine binding to 0.4 mg protein from brain microsomes. Scatchard analysis indicated a decrease in the number of binding sites without relevant changes in their affinity. The inhibitory potency of rat mesentery preparations on tritiated etorphine binding was : reduced but not abolished in the presence of soybean trypsin inhibitor; unaffected by EGTA 2.5 × 10−3M, which completely preserved binding to brain microsomes incubated with 50 ng/ml phospholipase A2 from porcine pancreas; increased by preincubation at 37°C with brain microsomes; variably affected - depending on the separately prepared batches of mesentery tested - by boiling, which however revealed a heat-resistent component consistently accounting to a large extent for the observed binding inhibition. Interference by an unidentified factor occurring in the mesentery - perhaps an opioid peptide - and possible contamination with pancreatic tissue containing proteases, presumably explain why previous studies failed to demonstrate in vitro opiate receptor binding in rat small intestine.