The rockefeller university

To help design needed new vaccines for pneumonic plague, we targeted the Yersinia pestis LcrV protein directly to CD8 alpha(+) DEC-205(+) or CD8 alpha(-) DCIR2(+) DC along with a clinically feasible adjuvant, poly IC By studying Y. pestis in mice, we could evaluate the capacity of this targeting approach to protect against a human pathogen. The DEC-targeted LcrV induced polarized Th1 immunity, whereas DCIR2-targeted LcrV induced fewer CD4(+) T cells secreting IFN-gamma, but higher IL-4, IL-5, IL-10, and IL-13 production. DCIR-2 targeting elicited higher anti-LcrV Ab titers than DEC targeting, which were comparable to a protein vaccine given in alhydrogel adjuvant, but the latter did not induce detectable T-cell immunity. When DEC- and DCIR2-targeted and F1-V+ alhydrogel-vaccinated mice were challenged 6 wk after vaccination with the virulent CO92 Y. pestis, the protection level and Ab titers induced by DCIR2 targeting were similar to those induced by F1-V protein with alhydrogel vaccination. Therefore, LcrV targeting to DC elicits combined humoral and cellular immunity, and for the first time with this approach, also induces protection in a mouse model for a human pathogen.

One important function of humoral immunity is toxin neutralization. The current view posits that neutralization results from antibody-mediated interference with the binding of toxins to their targets, a phenomenon viewed as dependent only on antibody specificity. To investigate the role of antibody constant region function in toxin neutralization, we generated IgG2a and IgG2b variants of the Bacillus anthracis protective antigen-binding IgG1 monoclonal antibody (mAb) 19D9. These antibodies express identical variable regions and display the same specificity. The efficacy of antibody-mediated neutralization was IgG2a > IgG2b > IgG1, and neutralization activity required competent Fc gamma receptor (Fc gamma R). The IgG2a mAb prevented lethal toxin cell killing and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase cleavage more efficiently than the IgG1 mAb. Passive immunization with IgG1 and IgG2a mAb protected wild-type mice, but not Fc gamma R-deficient mice, against B. anthracis infection. These results establish that constant region isotype influences toxin neutralization efficacy of certain antibodies through a mechanism that requires engagement of Fc gamma R. These findings highlight a new parameter for evaluating vaccine responses and the possibility of harnessing optimal Fc gamma R interactions in the design of passive immunization strategies.

CLC proteins transport chloride (Cl-) ions across cell membranes to control the electrical potential of muscle cells, transfer electrolytes across epithelia, and control the pH and electrolyte composition of intracellular organelles. Some members of this protein family are Cl- ion channels, whereas others are secondary active transporters that exchange Cl- ions and protons (H+) with a 2: 1 stoichiometry. We have determined the structure of a eukaryotic CLC transporter at 3.5 angstrom resolution. Cytoplasmic cystathionine beta-synthase (CBS) domains are strategically positioned to regulate the ion-transport pathway, and many disease-causing mutations in human CLCs reside on the CBS-transmembrane interface. Comparison with prokaryotic CLC shows that a gating glutamate residue changes conformation and suggests a basis for 2: 1 Cl-/H+ exchange and a simple mechanistic connection between CLC channels and transporters.

Handed asymmetry in organ shape and positioning is a common feature among bilateria, yet little is known about the morphogenetic mechanisms underlying left-right (LR) organogenesis. We utilize the directional 360 degrees clockwise rotation of genitalia in Drosophila to study LA-dependent organ looping. Using time-lapse imaging, we show that rotation of genitalia by 360 degrees results from an additive process involving two ring-shaped domains, each undergoing 180 degrees rotation. Our results show that the direction of rotation for each ring is autonomous and strictly depends on the LR determinant myosin ID (MyoID). Specific inactivation of MyoID in one domain causes rings to rotate in opposite directions and thereby cancels out the overall movement. We further reveal a specific pattern of apoptosis at the ring boundaries and show that local cell death is required for the movement of each domain, acting as a brake-releaser. These data indicate that organ looping can proceed through an incremental mechanism coupling LR determination and apoptosis. Furthermore, they suggest a model for the stepwise evolution of genitalia posture in Diptera, through the emergence and duplication of a 180 degrees LR module.

Inhibitor of Apoptosis Proteins (IAPs) are frequently overexpressed in tumors and have become promising targets for developing anti-cancer drugs. IAPs can be inhibited by natural antagonists, but a physiological requirement of mammalian IAP antagonists remains to be established. Here we show that deletion of the mouse Sept4 gene, which encodes the IAP antagonist ARTS, promotes tumor development. Sept4-null mice have increased numbers of hematopoietic stem and progenitor cells, elevated XIAP protein, increased resistance to cell death, and accelerated tumor development in an E mu-Myc background. These phenotypes are partially suppressed by inactivation of XIAP. Our results suggest that apoptosis plays an important role as a frontline defense against cancer by restricting the number of normal stem cells.

Gastrointestinal stromal tumour (GIST) is the most common human sarcoma and is primarily defined by activating mutations in the KIT or PDGFRA receptor tyrosine kinases(1,2). KIT is highly expressed in interstitial cells of Cajal (ICCs)-the presumed cell of origin for GIST-as well as in haematopoietic stem cells, melanocytes, mast cells and germ cells(2,3). Yet, families harbouring germline activating KIT mutations and mice with knock-in Kit mutations almost exclusively develop ICC hyperplasia and GIST(4-7), suggesting that the cellular context is important for KIT to mediate oncogenesis. Here we show that the ETS family member ETV1 is highly expressed in the subtypes of ICCs sensitive to oncogenic KIT mediated transformation(8), and is required for their development. In addition, ETV1 is universally highly expressed in GISTs and is required for growth of imatinib-sensitive and resistant GIST cell lines. Transcriptome profiling and global analyses of ETV1-binding sites suggest that ETV1 is a master regulator of an ICC-GIST-specific transcription network mainly through enhancer binding. The ETV1 transcriptional program is further regulated by activated KIT, which prolongs ETV1 protein stability and cooperates with ETV1 to promote tumorigenesis. We propose that GIST arises from ICCs with high levels of endogenous ETV1 expression that, when coupled with an activating KIT mutation, drives an oncogenic ETS transcriptional program. This differs from other ETS-dependent tumours such as prostate cancer, melanoma and Ewing sarcoma where genomic translocation or amplification drives aberrant ETS expression(9-11). It also represents a novel mechanism of oncogenic transcription factor activation.

We do not know how vocal learning came to be, but it is such a salient trait in human evolution that many have tried to imagine it. In primates this is difficult because we are the only species known to possess this skill. Songbirds provide a richer and independent set of data. I use comparative data and ask broad questions: How does vocal learning emerge during ontogeny? In what contexts? What are its benefits? How did it evolve from unlearned vocal signals? How was brain anatomy altered to enable vocal learning? What is the relation of vocal learning to adult neurogenesis? No one has described yet a circuit or set of circuits that can master vocal learning, but this knowledge may soon be within reach. Moreover, as we uncover how birds encode their learned song, we may also come closer to understanding how we encode our thoughts. (C) 2010 Published by Elsevier Inc.

The etiology of major depression remains unknown, but dysfunction of serotonergic signaling has long been implicated in the pathophysiology of this disorder. p11 is an S100 family member recently identified as a serotonin 1B [5-hydroxytryptamine 1B (5-HT(1B))] and serotonin 4 (5-HT(4)) receptor-binding protein. Mutant mice in which p11 is deleted show depression-like behaviors, suggesting that p11 may be a mediator of affective disorder pathophysiology. Using somatic gene transfer, we have now identified the nucleus accumbens as a key site of p11 action. Reduction of p11 with adeno-associated virus (AAV)-mediated RNA interference in the nucleus accumbens, but not in the anterior cingulate, of normal adult mice resulted in depression-like behaviors nearly identical to those seen in p11 knockout mice. Restoration of p11 expression specifically in the nucleus accumbens of p11 knockout mice normalized depression-like behaviors. Human nucleus accumbens tissue shows a significant reduction of p11 protein in depressed patients when compared to matched healthy controls. These results suggest that p11 loss in rodent and human nucleus accumbens may contribute to the pathophysiology of depression. Normalization of p11 expression within this brain region with AAV-mediated gene therapy may be of therapeutic value.

The inositol phosphatases phosphatase and tensin homologue (PTEN) and Src homology 2 domain-containing inositol phosphatase (SHIP) negatively regulate phosphatidylinositol-3-kinase (PI3K)-mediated growth, survival, and proliferation of hematopoietic cells. Although deletion of PTEN in mouse T cells results in lethal T cell lymphomas, we find that animals lacking PTEN or SHIP in B cells show no evidence of malignancy. However, concomitant deletion of PTEN and SHIP (bPTEN/SHIP(-/-)) results in spontaneous and lethal mature B cell neoplasms consistent with marginal zone lymphoma or, less frequently, follicular or centroblastic lymphoma. bPTEN/SHIP(-/-) B cells exhibit enhanced survival and express more MCL1 and less Bim. These cells also express low amounts of p27(kip1) and high amounts of cyclin D3 and thus appear poised to undergo proliferative expansion. Unlike normal B cells, bPTEN/SHIP(-/-) B cells proliferate to the prosurvival factor B cell activating factor (BAFF). Interestingly, although BAFF availability may promote lymphoma progression, we demonstrate that BAFF is not required for the expansion of transferred bPTEN/SHIP(-/-) B cells. This study reveals that PTEN and SHIP act cooperatively to suppress B cell lymphoma and provides the first direct evidence that SHIP is a tumor suppressor. As such, assessment of both PTEN and SHIP function are relevant to understanding the etiology of human B cell malignancies that exhibit augmented activation of the PI3K pathway.