A novel highly potent therapeutic antibody neutralizes multiple human chemokines and mimics viral immune modulation

Chemokines play a key role in leukocyte recruitment during inflammation and are implicated in the pathogenesis of a number of autoimmune diseases. As such, inhibiting chemokine signaling has been of keen interest for the development of therapeutic agents. This endeavor, however, has been hampered due to complexities in the chemokine system. Many chemokines have been shown to signal through multiple receptors and, conversely, most chemokine receptors bind to more than one chemokine. One approach to overcoming this complexity is to develop a single therapeutic agent that binds and inactivates multiple chemokines, similar to an immune evasion strategy utilized by a number of viruses. Here, we describe the development and characterization of a novel therapeutic antibody that targets a subset of human CC chemokines, specifically CCL3, CCL4, and CCL5, involved in chronic inflammatory diseases. Using a sequential immunization approach, followed by humanization and phage display affinity maturation, a therapeutic antibody was developed that displays high binding affinity towards the three targeted chemokines. In vitro, this antibody potently inhibits chemotaxis and chemokine-mediated signaling through CCR1 and CCR5, primary chemokine receptors for the targeted chemokines. Furthermore, we have demonstrated in vivo efficacy of the antibody in a SCID-hu mouse model of skin leukocyte migration, thus confirming its potential as a novel therapeutic chemokine antagonist. We anticipate that this antibody will have broad therapeutic utility in the treatment of a number of autoimmune diseases due to its ability to simultaneously neutralize multiple chemokines implicated in disease pathogenesis.     

Four loci explain 83% of size variation in the horse

Horse body size varies greatly due to intense selection within each breed. American Miniatures are less than one meter tall at the withers while Shires and Percherons can exceed two meters. The genetic basis for this variation is not known. We hypothesize that the breed population structure of the horse should simplify efforts to identify genes controlling size. In support of this, here we show with genome-wide association scans (GWAS) that genetic variation at just four loci can explain the great majority of horse size variation. Unlike humans, which are naturally reproducing and possess many genetic variants with weak effects on size, we show that horses, like other domestic mammals, carry just a small number of size loci with alleles of large effect. Furthermore, three of our horse size loci contain the LCORL, HMGA2 and ZFAT genes that have previously been found to control human height. The LCORL/NCAPG locus is also implicated in cattle growth and HMGA2 is associated with dog size. Extreme size diversification is a hallmark of domestication. Our results in the horse, complemented by the prior work in cattle and dog, serve to pinpoint those very few genes that have played major roles in the rapid evolution of size during domestication.     

Neighbor overlap is enriched in the yeast interaction network: analysis and implications

The yeast protein-protein interaction network has been shown to have distinct topological features such as a scale free degree distribution and a high level of clustering. Here we analyze an additional feature which is called Neighbor Overlap. This feature reflects the number of shared neighbors between a pair of proteins. We show that Neighbor Overlap is enriched in the yeast protein-protein interaction network compared with control networks carefully designed to match the characteristics of the yeast network in terms of degree distribution and clustering coefficient. Our analysis also reveals that pairs of proteins with high Neighbor Overlap have higher sequence similarity, more similar GO annotations and stronger genetic interactions than pairs with low ones. Finally, we demonstrate that pairs of proteins with redundant functions tend to have high Neighbor Overlap. We suggest that a combination of three mechanisms is the basis for this feature: The abundance of protein complexes, selection for backup of function, and the need to allow functional variation.     

Alleviation of gut inflammation by Cdx2/Pxr pathway in a mouse model of chemical colitis

Pregnane X Receptor (PXR), a master regulator of drug metabolism and inflammation, is abundantly expressed in the gastrointestinal tract. Baicalein and its O-glucuronide baicalin are potent anti-inflammatory and anti-cancer herbal flavonoids that undergo a complex cycle of interconversion in the liver and gut. We sought to investigate the role these flavonoids play in inhibiting gut inflammation by an axis involving PXR and other potential factors. The consequences of PXR regulation and activation by the herbal flavonoids, baicalein and baicalin were evaluated in vitro in human colon carcinoma cells and in vivo using wild-type, Pxr-null, and humanized (hPXR) PXR mice. Baicalein, but not its glucuronidated metabolite baicalin, activates PXR in a Cdx2-dependent manner in vitro, in human colon carcinoma LS174T cells, and in the murine colon in vivo. While both flavonoids abrogate dextran sodium sulfate (DSS)-mediated colon inflammation in vivo, oral delivery of a potent bacterial β-glucuronidase inhibitor eliminates baicalin's effect on gastrointestinal inflammation by preventing the microbial conversion of baicalin to baicalien. Finally, reduction of gastrointestinal inflammation requires the binding of Cdx2 to a specific proximal site on the PXR promoter. Pharmacological targeting of intestinal PXR using natural metabolically labile ligands could serve as effective and potent therapeutics for gut inflammation that avert systemic drug interactions.     

Visually guided avoidance in the chameleon (Chamaeleo chameleon): response patterns and lateralization

The common chameleon, Chamaeleo chameleon, is an arboreal lizard with highly independent, large-amplitude eye movements. In response to a moving threat, a chameleon on a perch responds with distinct avoidance movements that are expressed in its continuous positioning on the side of the perch distal to the threat. We analyzed body-exposure patterns during threat avoidance for evidence of lateralization, that is, asymmetry at the functional/behavioral levels. Chameleons were exposed to a threat approaching horizontally from the left or right, as they held onto a vertical pole that was either wider or narrower than the width of their head, providing, respectively, monocular or binocular viewing of the threat. We found two equal-sized sub-groups, each displaying lateralization of motor responses to a given direction of stimulus approach. Such an anti-symmetrical distribution of lateralization in a population may be indicative of situations in which organisms are regularly exposed to crucial stimuli from all spatial directions. This is because a bimodal distribution of responses to threat in a natural population will reduce the spatial advantage of predators.     

WNT7B in fibroblastic foci of idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a devastating interstitial pneumonia causing a loss of respiratory surface area due to a proliferative fibrotic response involving hyperplastic, hypertrophic, and metaplastic epithelium, cystic honeycomb change, septal expansion, and variable inflammation. Wnt (wingless) signaling glycoproteins are known to be involved in lung development and tissue repair, and are up-regulated in patients with IPF. Based on previous qRT-PCR data showing increased Wnt7B in lungs of IPF patients, a systematic, quantitative examination of its tissue site distribution was undertaken.

Methods

Tissue samples from the Lung Tissue Research Consortium (LTRC) of 39 patients diagnosed with mild to severe IPF/usual interstitial pneumonia (UIP) and 19 normal patients were examined for the immunolocalization of Wnt7B.

Results

In normal lung, moderate Wnt7B reactivity was confined to airway epithelium, smooth muscle of airways and vasculature, and macrophages. IPF lung showed strong Wnt7B reactivity in fibroblastic foci, dysplastic airway and alveolar epithelium, and in highly discrete subepithelial, basement membrane-associated regions. All reactive sites were sized and counted relative to specific microscopic regions. Those in the subepithelial sites were found in significantly greater numbers and larger relative area compared with the others. No reactive sites were present in normal patient controls.

Conclusions

The results demonstrate Wnt7B to be expressed at high concentrations in regions of active hyperplasia, metaplasia, and fibrotic change in IPF patients. In this context and its previously established biologic activities, Wnt7B would be expected to be of potential importance in the pathogenesis of IPF.     

Early F-actin disorganization may be signaling vacuole disruption in incompatible pollen tubes of Nicotiana alata

Self-incompatibility (SI) systems appeared early in plant evolution as an effective mechanism to promote outcrossing and avoid inbreeding depression. These systems prevent self-fertilization by the recognition and rejection of self-pollen and pollen from closely related individuals. The most widespread SI system is based on the action of a pistil ribonuclease, the S-RNase, which recognizes and rejects incompatible pollen. S-RNases are endocyted by pollen tubes and stored into vacuoles. By a mechanism that is still unknown, these vacuoles are selectively disrupted in incompatible pollen, releasing S-RNases into the cytoplasm and allowing degradation of pollen RNA. Recently, we have studied the timing of in vivo alterations of pollen F-actin cytoskeleton after incompatible pollinations. Besides being essential for pollen growth, F-actin cytoskeleton is a very dynamic cellular component. Changes in F-actin organization are known to be capable of transducing signaling events in many cellular processes. Early after pollination, F-actin showed a progressive disorganization in incompatible pollen tubes. However by the time the F-actin was almost completely disrupted, the large majority of vacuolar compartments were still intact. These results indicate that in incompatible pollen tubes F-actin disorganization precedes vacuolar disruption. They also suggest that F-actin may act as an early transducer of signals triggering the rejection of incompatible pollen.