Assessment of experimental saccular aneurysm using selective angiography in common carotid artery of rabbits

In order to study the treatment of aneurysms, the technique of making experimental aneurysms in laboratory animals must be established. In our study, to examine the feasibility of making experimental aneurysm and selective angiography on the common carotid artery in rabbits and to determine the size of experimental aneurysm after surgery, saccular aneurysms were fashioned on the right common carotid artery in 17 rabbits using a vein pouch technique. Selective angiography of the common carotid artery was performed immediately after surgery, and at 1 week, 4 weeks, and 8 weeks after surgery. Also, histological changes in the aneurysms were observed. In 16 rabbits with established successful experimental aneurysm, no differences were found in diet intake and behavior before and after surgery. The patency of the carotid artery was confirmed by selective angiography. The average size of the aneurysm immediately after surgery was similar to that of 1 week postoperatively in selective angiography, however it increased with time at 4weeks and 8 weeks. Histologically, infiltration of inflammatory cells and hemorrhage were found at the junction of the carotid artery and the vein pouch at 1 week, which disappeared at 4 weeks and 8 weeks. This study suggests experimental saccular aneurysm using the vein pouch technique might form aneurysms similar to that of the human in its properties such as increment of size, and selective angiography might be suitable for assessment of experimental aneurysm. Therefore, this animal model may be suitable for investigating new treatment methodologies for human aneurysms

The glycolytic enzyme phosphofructokinase-1 assembles into filaments.

Despite abundant knowledge of the regulation and biochemistry of glycolytic enzymes, we have limited understanding on how they are spatially organized in the cell. Emerging evidence indicates that nonglycolytic metabolic enzymes regulating diverse pathways can assemble into polymers. We now show tetramer- and substrate-dependent filament assembly by phosphofructokinase-1 (PFK1), which is considered the "gatekeeper" of glycolysis because it catalyzes the step committing glucose to breakdown. Recombinant liver PFK1 (PFKL) isoform, but not platelet PFK1 (PFKP) or muscle PFK1 (PFKM) isoforms, assembles into filaments. Negative-stain electron micrographs reveal that filaments are apolar and made of stacked tetramers oriented with exposed catalytic sites positioned along the edge of the polymer. Electron micrographs and biochemical data with a PFKL/PFKP chimera indicate that the PFKL regulatory domain mediates filament assembly. Quantified live-cell imaging shows dynamic properties of localized PFKL puncta that are enriched at the plasma membrane. These findings reveal a new behavior of a key glycolytic enzyme with insights on spatial organization and isoform-specific glucose metabolism in cells

Prevalence of Unruptured Intracranial Aneurysm on MR Angiography

Objective: To evaluate the prevalence of incidentally found unruptured intracranial aneurysms (UIAs) on the brain MR angiography (MRA) from a community-based general hospital. Materials and Methods: This was a prospectively collected retrospective study, carried out from January 2004 to December 2004. The subjects included 3049 persons from a community-based hospital in whom MRA was performed according to a standardized protocol in an outpatient setting. Age- and sex-specific prevalence of UIAs was calculated. The results by MRA were compared with intra-arterial digital subtraction angiography (DSA) findings. Results: Unruptured intracranial aneurysms were found in 137 (5%) of the 3049 patients (M:F = 43:94; mean age, 60.2 years). The prevalence of UIAs was 5 % (n = 94) in women and 4 % (n = 43) in men, respectively (p = 0.2046) and showed no age-related increase. The most common site of aneurysm was at the distal internal carotid artery (n = 64, 39%), followed by the middle cerebral artery (n = 40, 24%). In total, 99 % of aneurysms measured less than 12 mm, and 93 % of aneurysms measured less than 7 mm. Direct comparisons between MRA and DSA were available in 70 patients with 83 UIAs; the results revealed two false positive and two false negative results. Conclusion: This community-hospital based study suggested a higher prevalence of UIAs observed by MRA than previously reported. These findings should be anticipated in the design and use of neuroimaging in clinical practice. Index terms: MR angiography; Intracranial aneurysm; Prevalenc

Estimation of Cell Cycle States of Human Melanoma Cells with Quantitative Phase Imaging and Deep Learning

Visualization and classification of cell cycle stages in live cells requires the introduction of transient or stably expressing fluorescent markers. This is not feasible for all cell types, and can be time consuming to implement. Labelling of living cells also has the potential to perturb normal cellular function. Here we describe a computational strategy to estimate core cell cycle stages without markers by taking advantage of features extracted from information-rich ptychographic time-lapse movies. We show that a deep-learning approach can estimate the cell cycle trajectories of individual human melanoma cells from short 3-frame (~23 minute) snapshots, and can identify cell cycle arrest induced by chemotherapeutic agents targeting melanoma driver mutations

FGFR2-activating mutations disrupt cell polarity to potentiate migration and invasion in endometrial cancer cell models

Fibroblast growth factor receptors (FGFRs) are a family of receptor tyrosine kinases that control a diverse range of biological processes during development and in adult tissues. We recently reported that somatic FGFR2 mutations are associated with shorter survival in endometrial cancer. However, little is known about how these FGFR2 mutations contribute to endometrial cancer metastasis. Here, we report that expression of the activating mutations FGFR2N550K and FGFR2Y376C in an endometrial cancer cell model induce Golgi fragmentation, and loss of polarity and directional migration. In mutant FGFR2-expressing cells, this was associated with an inability to polarise intracellular pools of FGFR2 towards the front of migrating cells. Such polarization defects were exacerbated in three-dimensional culture, where FGFR2 mutant cells were unable to form well-organised acini, instead undergoing exogenous ligand-independent invasion. Our findings uncover collective cell polarity and invasion as common targets of disease-associated FGFR2 mutations that lead to poor outcome in endometrial cancer patients

β-Catenin is a pH sensor with decreased stability at higher intracellular pH.

β-Catenin functions as an adherens junction protein for cell-cell adhesion and as a signaling protein. β-catenin function is dependent on its stability, which is regulated by protein-protein interactions that stabilize β-catenin or target it for proteasome-mediated degradation. In this study, we show that β-catenin stability is regulated by intracellular pH (pHi) dynamics, with decreased stability at higher pHi in both mammalian cells and Drosophila melanogaster β-Catenin degradation requires phosphorylation of N-terminal residues for recognition by the E3 ligase β-TrCP. While β-catenin phosphorylation was pH independent, higher pHi induced increased β-TrCP binding and decreased β-catenin stability. An evolutionarily conserved histidine in β-catenin (found in the β-TrCP DSGIHS destruction motif) is required for pH-dependent binding to β-TrCP. Expressing a cancer-associated H36R-β-catenin mutant in the Drosophila eye was sufficient to induce Wnt signaling and produced pronounced tumors not seen with other oncogenic β-catenin alleles. We identify pHi dynamics as a previously unrecognized regulator of β-catenin stability, functioning in coincidence with phosphorylation

The Role of Melanoma Cell-Stroma Interaction in Cell Motility, Invasion, and Metastasis

The importance of studying cancer cell invasion is highlighted by the fact that 90% of all cancer-related mortalities are due to metastatic disease. Melanoma metastasis is driven fundamentally by aberrant cell motility within three-dimensional or confined environments. Within this realm of cell motility, cytokines, growth factors, and their receptors are crucial for engaging signaling pathways, which both mediate crosstalk between cancer, stromal, and immune cells in addition to interactions with the surrounding microenvironment. Recently, the study of the mechanical biology of tumor cells, stromal cells and the mechanics of the microenvironment have emerged as important themes in driving invasion and metastasis. While current anti-melanoma therapies target either the MAPK signaling pathway or immune checkpoints, there are no drugs available that specifically inhibit motility and thus invasion and dissemination of melanoma cells during metastasis. One of the reasons for the lack of so-called “migrastatics” is that, despite decades of research, the precise biology of metastatic disease is still not fully understood. Metastatic disease has been traditionally lumped into a single classification, however what is now emergent is that the biology of melanoma metastasis is highly diverse, heterogeneous and exceedingly dynamic—suggesting that not all cases are created equal. The following mini-review discusses melanoma heterogeneity in the context of the emergent theme of mechanobiology and how it influences the tumor-stroma crosstalk during metastasis. Thus, highlighting future therapeutic options for migrastatics and mechanomedicines in the prevention and treatment of metastatic melanoma

Talin-KANK1 interaction controls the recruitment of cortical microtubule stabilizing complexes to focal adhesions

The cross-talk between dynamic microtubules and integrin-based adhesions to the extracellular matrix plays a crucial role in cell polarity and migration. Microtubules regulate the turnover of adhesion sites, and, in turn, focal adhesions promote cortical microtubule capture and stabilization in their vicinity, but the underlying mechanism is unknown. Here, we show that cortical microtubule stabilization sites containing CLASPs, KIF21A, LL5? and liprins are recruited to focal adhesions by the adaptor protein KANK1, which directly interacts with the major adhesion component, talin. Structural studies showed that the conserved KN domain in KANK1 binds to the talin rod domain R7. Perturbation of this interaction, including a single point mutation in talin, which disrupts KANK1 binding but not the talin function in adhesion, abrogates the association of microtubule-stabilizing complexes with focal adhesions. We propose that the talin-KANK1 interaction links the two macromolecular assemblies that control cortical attachment of actin fibers and microtubules