Constraining Deformation in the North Pamir and the Westernmost Tarim Basin

Abstract HKT-ISTP 2013 A

Comprehensive Analysis of the 16p11.2 Deletion and Null Cntnap2 Mouse Models of Autism Spectrum Disorder

Autism spectrum disorder comprises several neurodevelopmental conditions presenting symptoms in social communication and restricted, repetitive behaviors. A major roadblock for drug development for autism is the lack of robust behavioral signatures predictive of clinical efficacy. To address this issue, we further characterized, in a uniform and rigorous way, mouse models of autism that are of interest because of their construct validity and wide availability to the scientific community. We implemented a broad behavioral battery that included but was not restricted to core autism domains, with the goal of identifying robust, reliable phenotypes amenable for further testing. Here we describe comprehensive findings from two known mouse models of autism, obtained at different developmental stages, using a systematic behavioral test battery combining standard tests as well as novel, quantitative, computer-vision based systems. The first mouse model recapitulates a deletion in human chromosome 16p11.2, found in 1% of individuals with autism. The second mouse model harbors homozygous null mutations in Cntnap2, associated with autism and Pitt-Hopkins-like syndrome. Consistent with previous results, 16p11.2 heterozygous null mice, also known as Del(7Slx1b-Sept1)4Aam weighed less than wild type littermates displayed hyperactivity and no social deficits. Cntnap2 homozygous null mice were also hyperactive, froze less during testing, showed a mild gait phenotype and deficits in the three-chamber social preference test, although less robust than previously published. In the open field test with exposure to urine of an estrous female, however, the Cntnap2 null mice showed reduced vocalizations. In addition, Cntnap2 null mice performed slightly better in a cognitive procedural learning test. Although finding and replicating robust behavioral phenotypes in animal models is a challenging task, such functional readouts remain important in the development of therapeutics and we anticipate both our positive and negative findings will be utilized as a resource for the broader scientific community

Targeting BTK for the treatment of FLT3-ITD mutated acute myeloid leukemia

Approximately 20% of patients with acute myeloid leukaemia (AML) have a mutation in FMS-like-tyrosine-kinase-3 (FLT3). FLT3 is a trans-membrane receptor with a tyrosine kinase domain which, when activated, initiates a cascade of phosphorylated proteins including the SRC family of kinases. Recently our group and others have shown that pharmacologic inhibition and genetic knockdown of Bruton's tyrosine kinase (BTK) blocks AML blast proliferation, leukaemic cell adhesion to bone marrow stromal cells as well as migration of AML blasts. The anti-proliferative effects of BTK inhibition in human AML are mediated via inhibition of downstream NF-κB pro-survival signalling however the upstream drivers of BTK activation in human AML have yet to be fully characterised. Here we place the FLT3-ITD upstream of BTK in AML and show that the BTK inhibitor ibrutinib inhibits the survival and proliferation of FLT3-ITD primary AML blasts and AML cell lines. Furthermore ibrutinib inhibits the activation of downstream kinases including MAPK, AKT and STAT5. In addition we show that BTK RNAi inhibits proliferation of FLT3-ITD AML cells. Finally we report that ibrutinib reverses the cyto-protective role of BMSC on FLT3-ITD AML survival. These results argue for the evaluation of ibrutinib in patients with FLT3-ITD mutated AML

Genome-Wide Profiling of H3K56 Acetylation and Transcription Factor Binding Sites in Human Adipocytes

The growing epidemic of obesity and metabolic diseases calls for a better understanding of adipocyte biology. The regulation of transcription in adipocytes is particularly important, as it is a target for several therapeutic approaches. Transcriptional outcomes are influenced by both histone modifications and transcription factor binding. Although the epigenetic states and binding sites of several important transcription factors have been profiled in the mouse 3T3-L1 cell line, such data are lacking in human adipocytes. In this study, we identified H3K56 acetylation sites in human adipocytes derived from mesenchymal stem cells. H3K56 is acetylated by CBP and p300, and deacetylated by SIRT1, all are proteins with important roles in diabetes and insulin signaling. We found that while almost half of the genome shows signs of H3K56 acetylation, the highest level of H3K56 acetylation is associated with transcription factors and proteins in the adipokine signaling and Type II Diabetes pathways. In order to discover the transcription factors that recruit acetyltransferases and deacetylases to sites of H3K56 acetylation, we analyzed DNA sequences near H3K56 acetylated regions and found that the E2F recognition sequence was enriched. Using chromatin immunoprecipitation followed by high-throughput sequencing, we confirmed that genes bound by E2F4, as well as those by HSF-1 and C/EBPα, have higher than expected levels of H3K56 acetylation, and that the transcription factor binding sites and acetylation sites are often adjacent but rarely overlap. We also discovered a significant difference between bound targets of C/EBPα in 3T3-L1 and human adipocytes, highlighting the need to construct species-specific epigenetic and transcription factor binding site maps. This is the first genome-wide profile of H3K56 acetylation, E2F4, C/EBPα and HSF-1 binding in human adipocytes, and will serve as an important resource for better understanding adipocyte transcriptional regulation.Singapore. Agency for Science, Technology and Research (National Science Scholarship )Massachusetts Institute of Technology (Eugene Bell Career Development Chair)National Science Foundation (U.S.) (Award No. DBI-0821391)Pfizer Inc

Intestinal lesions in dogs with acute hemorrhagic diarrhea syndrome associated with netF-positive Clostridium perfringens type A

Acute hemorrhagic diarrhea syndrome (AHDS), formerly named canine hemorrhagic gastroenteritis, is one of the most common causes of acute hemorrhagic diarrhea in dogs, and is characterized by acute onset of diarrhea, vomiting, and hemoconcentration. To date, histologic examinations have been limited to postmortem specimens of only a few dogs with AHDS. Thus, the aim of our study was to describe in detail the distribution, character, and grade of microscopic lesions, and to investigate the etiology of AHDS. Our study comprised 10 dogs with AHDS and 9 control dogs of various breeds, age, and sex. Endoscopic biopsies of the gastrointestinal tract were taken and examined histologically (H&E, Giemsa), immunohistochemically (Clostridium spp., parvovirus), and bacteriologically. The main findings were acute necrotizing and neutrophilic enterocolitis (9 of 10) with histologic detection of clostridia-like, gram-positive bacteria on the necrotic mucosal surface (9 of 10). Clostridium perfringens isolated from the duodenum was identified as type A (5 of 5) by multiplex PCR (5 of 5). In addition, each of the 5 genotyped isolates encoded the pore-forming toxin netF. Clostridium spp. (not C. perfringens) were cultured from duodenal biopsies in 2 of 9 control dogs. These findings suggest that the pore-forming netF toxin is responsible for the necrotizing lesions in the intestines of a significant proportion of dogs with AHDS. Given that the stomach was not involved in the process, the term acute hemorrhagic diarrhea syndrome seems more appropriate than the frequently used term hemorrhagic gastroenteritis

Prime movers : mechanochemistry of mitotic kinesins

Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation

Unusual Field-Insensitive Phase Transition and Kondo Behavior in SmTi2_2Al20_{20}

Magnetization, electrical resistivity and specific heat measurements were performed on high-quality single crystalline SmTi$_2$Al$_{20}$ (residual resistivity ratio $\sim$ 40) grown by Al self-flux method. A Kondo-like $\log T$ dependence in the resistivity is observed below 50 K. We discovered a field-insensitive phase transition at $T_{x}$ = 6.5 K and a field-insensitive heavy fermion behavior with the electronic specific heat coefficient $\gamma$ = 150 mJ/(K$^{2}$ mol). Specific heat analysis reveals that the ground state is a $\Gamma_{8}$ quartet state and the Sm magnetic dipole moment $m_{{\rm Sm}}$ ($\sim 0.5 \mu_{{\rm B}}$ at $T \simeq$ 0) orders below $T_{x}$ in spite of the field-insensitive behavior. Possible reasons for the field insensitiveness will be discussed.Comment: 4 pages, 3 figures, to be published in J. Phys. Soc. Jpn. 80 (2011

Characterization of AKT independent effects of the synthetic AKT inhibitors SH-5 and SH-6 using an integrated approach combining transcriptomic profiling and signaling pathway perturbations

<p>Abstract</p> <p>Background</p> <p>Signal transduction processes mediated by phosphatidyl inositol phosphates affect a broad range of cellular processes such as cell cycle progression, migration and cell survival. The protein kinase AKT is one of the major effectors in this signaling network. Chronic AKT activation contributes to oncogenic transformation and tumor development. Therefore, analogs of phosphatidyl inositol phosphates (PIAs) were designed as new small drugs to block AKT activity for cancer treatment. Here we characterize the biological effects of the PIAs SH-5 and SH-6 in colorectal cancer cell lines.</p> <p>Methods</p> <p>Serum-starved or serum-supplemented human colorectal cancer cell lines SW480, HT29 and HCT116 were exposed to SH-5 and SH-6. AKT activation was determined by western blotting. Cell viability was assessed using a colorimetric XTT-based assay, apoptosis and cell cycle changes were monitored by FACS analysis. The dynamics of cell morphology alterations was evaluated by confocal and time-lapse microscopy. Transcriptional changes due to inhibitor treatment were analyzed using Affymetrix HG-U133A microarrays and RT-PCR.</p> <p>Results</p> <p>While the PIAs clearly reduce AKT phosphorylation in serum starved cells, we did not observe a significant reduction under serum supplemented conditions, giving us the opportunity to analyze AKT independent effects of these compounds. Both inhibitors induce broadly the same morphological alterations, in particular changes in cell shape and formation of intracellular vesicles. Moreover, we observed the induction of binucleated cells specifically in the SW480 cell line. Gene expression analysis revealed transcriptional alterations, which are mostly cell line specific. In accordance to the phenotype we found a gene group associated with mitosis and spindle organization down regulated in SW480 cells, but not in the other cell lines. A bioinformatics analysis using the Connectivity Map linked the gene expression pattern of the inhibitor treated SW480 cells to PKC signaling. Using confocal laser scanning microscopy and time lapse recording we identified a specific defect in the last step of the cytokinesis as responsible for the binucleation.</p> <p>Conclusions</p> <p>The PIAs SH-5 and SH-6 impinge on additional cellular targets apart from AKT in colorectal cancer cells. The effects are mostly cell line specific and have an influence at the outcome of the treatment. In view of potential clinical trials it will be necessary to take these diverse effects into consideration to optimize patient treatment.</p