Inflammation-dependent alpha 5 beta 1 (very late antigen-5) expression on leukocytes reveals a functional role for this integrin in acute peritonitis.

The potential role of alpha 5 beta 1 (VLA-5) in leukocyte trafficking in zymosan-induced acute peritonitis was determined. In naïve mice, approximately 98% of Gr1(high) cells (PMN) in bone marrow and circulation were alpha 5 beta 1-negative; these profiles were modestly affected by peritoneal injection of zymosan. In contrast, approximately 30% of Gr1(high) cells recruited by zymosan (24 h) to the peritoneal cavity expressed alpha 5 beta 1. With respect to F4/80(+) cells, approximately 60% of bone marrow and peripheral blood populations expressed alpha 5 beta 1, with approximately 90% positivity in resident cells of noninflamed peritoneum. Analysis of alpha 5 beta 1 expression revealed inflammation-dependent increased expression on Gr1(high) and F4/80(+) cells in bone marrow, blood, and peritoneal cavity. Blockade of alpha 5 beta 1, by an anti-alpha 5 mAb, attenuated zymosan-induced 24 h recruitment of Gr1(high) and F4/80(+) cells. At least one underlying mechanism of this action was reduction of cell adhesion and transmigration across microvascular vessels, as revealed by intravital microscopy. Confocal analyses indicated that deposition of fibronectin, the principal ligand for alpha 5 beta 1, was up-regulated significantly on and around the inflamed mesenteric microvasculature. These data suggest that the effects of alpha 5-blockade may be a result of inhibition of alpha 5 beta 1-dependent leukocyte adhesion to and migration along the fibronectin matrix. This is the first report that identifies a functional role for alpha 5 beta 1 in leukocyte trafficking during acute inflammation.

alpha5beta1 Integrin blockade inhibits lymphangiogenesis in airway inflammation.

The integrin alpha5beta1 has been previously implicated in tumor angiogenesis, but its role in the remodeling of both blood vessels and lymphatics during inflammation is at an early stage of understanding. We examined this issue using a selective, small-molecule inhibitor of alpha5beta1 integrin, 2-aroylamino-3-{4-[(pyridin-2-ylaminomethyl)heterocyclyl]phenyl}propionic acid (JSM8757), in a model of sustained airway inflammation in mice with Mycoplasma pulmonis infection, which is known to be accompanied by robust blood vessel remodeling and lymphangiogenesis. The inhibitor significantly decreased the proliferation of lymphatic endothelial cells in culture and the number of lymphatic sprouts and new lymphatics in airways of mice infected for 2 weeks but did not reduce remodeling of blood vessels in the same airways. In inflamed airways, alpha5 integrin immunoreactivity was present on lymphatic sprouts, but not on collecting lymphatics or blood vessels, and was not found on any lymphatics of normal airways. Macrophages, potential targets of the inhibitor, did not have alpha5 integrin immunoreactivity in inflamed airways. In addition, macrophage recruitment, assessed in infected airways by quantitative reverse transcription-polymerase chain reaction measurements of expression of the marker protein ionized calcium-binding adapter molecule 1 (Iba1), was not reduced by JSM8757. We conclude that inhibition of the alpha5beta1 integrin reduces lymphangiogenesis in inflamed airways after M. pulmonis infection because expression of the integrin is selectively increased on lymphatic sprouts and plays an essential role in lymphatic growth.

Identification of hPin1 inhibitors that induce apoptosis in a mammalian Ras transformed cell line.

The authors have developed a class of potent inhibitors against the phosphate specific prolyl isomerase hPin1, which induced apoptosis in transformed cell lines.

Galantamine is an allosterically potentiating ligand of neuronal nicotinic but not of muscarinic acetylcholine receptors.

Galantamine (Reminyl), an approved treatment for Alzheimer's disease (AD), is a potent allosteric potentiating ligand (APL) of human alpha 3 beta 4, alpha 4 beta 2, and alpha 6 beta 4 nicotinic receptors (nAChRs), and of the chicken/mouse chimeric alpha 7/5-hydroxytryptamine3 receptor, as was shown by whole-cell patch-clamp studies of human embryonic kidney-293 cells stably expressing a single nAChR subtype. Galantamine potentiates agonist responses of the four nAChR subtypes studied in the same window of concentrations (i.e., 0.1-1 microM), which correlates with the cerebrospinal fluid concentration of the drug at the recommended daily dosage of 16 to 24 mg. At concentrations >10 microM, galantamine acts as an nAChR inhibitor. The other presently approved AD drugs, donepezil and rivastigmine, are devoid of the nicotinic APL action; at micromolar concentrations they also block nAChR activity. Using five CHO-SRE-Luci cell lines, each of them expressing a different human muscarinic receptor, and a reporter gene assay, we show that galantamine does not alter the activity of M1-M5 receptors, thereby confirming that galantamine modulates selectively the activity of nAChRs. These studies support our previous proposal that the therapeutic action of galantamine is mainly produced by its sensitizing action on nAChRs rather than by general cholinergic enhancement due to cholinesterase inhibition. Galantamine's APL action directly addresses the nicotinic deficit in AD.