Dataset Information

L-selectin-mediated lymphocyte-cancer cell interactions under low fluid shear conditions.

ABSTRACT: Cell migration in blood flow is mediated by engagement of specialized adhesion molecules that function under hemodynamic shear conditions, and many of the effectors of these adhesive interactions, such as the selectins and their ligands, are well defined. However, in contrast, our knowledge of the adhesion molecules operant under lymphatic flow conditions is incomplete. Among human malignancies, head and neck squamous cell cancer displays a marked predilection for locoregional lymph node metastasis. Based on this distinct tropism, we hypothesized that these cells express adhesion molecules that promote their binding to lymphoid tissue under lymphatic fluid shear stress. Accordingly, we investigated adhesive interactions between these and other cancer cells and the principal resident cells of lymphoid organs, lymphocytes. Parallel plate flow chamber studies under defined shear conditions, together with biochemical analyses, showed that human head and neck squamous cell cancer cells express heretofore unrecognized L-selectin ligand(s) that mediate binding to lymphocyte L-selectin at conspicuously low shear stress levels of 0.07-0.08 dynes/cm(2), consistent with lymphatic flow. The binding of head and neck squamous cancer cells to L-selectin displays canonical biochemical features, such as requirements for sialylation, sulfation, and N-glycosylation, but displays a novel operational shear threshold differing from all other L-selectin ligands, including those expressed on colon cancer and leukemic cells (e.g. HCELL). These data define a novel class of L-selectin ligands and expand the scope of function for L-selectin within circulatory systems to now include a novel activity within shear stresses characteristic of lymphatic flow.

SUBMITTER: Resto VA

PROVIDER: S-EPMC2414279 | biostudies-literature | 2008 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

L-selectin-mediated lymphocyte-cancer cell interactions under low fluid shear conditions.

Resto Vicente A VA Burdick Monica M MM Dagia Nilesh M NM McCammon Susan D SD Fennewald Susan M SM Sackstein Robert R

The Journal of biological chemistry 20080401 23

Cell migration in blood flow is mediated by engagement of specialized adhesion molecules that function under hemodynamic shear conditions, and many of the effectors of these adhesive interactions, such as the selectins and their ligands, are well defined. However, in contrast, our knowledge of the adhesion molecules operant under lymphatic flow conditions is incomplete. Among human malignancies, head and neck squamous cell cancer displays a marked predilection for locoregional lymph node metasta ...[more]

PMID: 18385135

Similar Datasets

Project description:Western blotting has proven to be an important technique in analysis of receptor-ligand interactions (i.e., by ligand blotting) and for identifying molecules mediating cell attachment (i.e., by cell blotting). Conventional ligand blotting and cell blotting methods employ nondynamic (static) incubation conditions, whereby molecules or cells of interest are placed in suspension and overlaid on membranes. However, many cell-cell and cell-matrix adhesive interactions occur under fluid shear conditions, and shear stress itself mediates and/or facilitates the engagement of these physiologically appropriate receptors and ligands. Notably, shear forces critically influence the adhesion of circulating cells and platelets to vessel walls in physiologic cell migration and hemostasis, as well as in inflammatory and thrombotic disorders, cancer metastasis, and atherosclerosis. Use of nondynamic blotting conditions to analyze such interactions can introduce bias, overtly missing relevant effectors and/or exaggerating the relative role(s) of nonphysiologic adhesion molecules. To address this shortfall, we have developed a new technique for identifying binding interactions under fluid shear conditions, the "blot rolling assay." Using this method, molecules in a complex mixture are resolved by gel electrophoresis, transferred to a membrane that is rendered semi-transparent, and the membrane is then incorporated into a parallel-plate flow chamber apparatus. Under controlled flow conditions, cells or particles bearing adhesion proteins of interest are then introduced into the chamber and interactions with individual immobilized molecules (bands) can be visualized in real-time. The substrate molecule(s) supporting adhesion under fluid shear can then be identified by staining with specific antibodies or by excising the relevant band(s) and performing mass spectrometry or microsequencing of the isolated material. This method thus allows for the identification, within a complex mixture and without prior isolation or purification, of both known and previously uncharacterized adhesion molecules operational under dynamic conditions.

Project description:The opportunistic pathogen, Staphylococcus aureus, encounters a wide variety of fluid shear levels within the human host, which may play a key role in dictating whether this organism adopts a commensal interaction with the host or transitions to cause disease. Using rotating-wall vessel bioreactors to create a physiologically-relevant, low fluid shear environment, S. aureus was evaluated for cellular responses that could impact its colonization and virulence. S. aureus cells grown in a low fluid shear environment initiated a novel attachment-independent biofilm phenotype and were completely encased in extracellular polymeric substances. Compared to controls, low-shear cultured cells displayed slower growth and repressed virulence characteristics, including decreased carotenoid production, increased susceptibility to oxidative stress, and reduced survival in whole blood. Transcriptional whole genome microarray profiling suggested alterations in metabolic pathways. Further genetic expression analysis revealed the down-regulation of the RNA chaperone Hfq, which parallels low fluid shear responses of certain Gram negative organisms. This is the first study to report an Hfq association to fluid shear in a Gram positive organism, suggesting an evolutionarily conserved response to fluid shear among structurally diverse prokaryotes. Collectively, our results suggest S. aureus responds to a low fluid shear environment by initiating a biofilm/colonization phenotype with diminished virulence characteristics, which could lead to insight into key factors influencing the divergence between infection and colonization during initial host pathogen interaction. Genetic expression profiles of Staphylococcus aureus cultured under low fluid shear conditions was compared to control cultures of S. aureus which was cultured in identical hardware in an orientation disrupting the low fluid shear effect. Samples from the same date of culture were compared (control 21:low 21 and control 30: low 30). S. aureus was cultured for 20 hours in either the low fluid shear or control orientated rotating wall vessel (RWV) bioreactor at which point the cells were removed and RNA extracted. At 20 hours, both cultures were in the same stage of growth (stationary phase) and at this point phenotypic differences between control and low fluid shear cultures were noted.

Project description:Surfactant-based viscoelastic (SBVE) fluids are innovative nonpolymeric non-newtonian fluid compositions that have recently gained much attention from the oil industry. SBVE can replace traditional polymeric fracturing fluid composition by mitigating problems arising during and after hydraulic fracturing operations are performed. In this study, SBVE fluid systems which are entangled with worm-like micellar solutions of cationic surfactant: cetrimonium bromide or CTAB and counterion inorganic sodium nitrate salt are synthesized. The salt reagent concentration is optimized by comparing the rheological characteristics of different concentration fluids at 25 °C. The study aims to mitigate the primary issue concerning these SBVE fluids: significant drop in viscosity at high temperature and high shear rate (HTHS) conditions. Hence, the authors synthesized a modified viscoelastic fluid system using ZnO nanoparticle (NPs) additives with a hypothesis of getting fluids with improved rheology. The rheology of optimum fluids of both categories: with (0.6 M NaNO3 concentration fluid) and without (0.8 M NaNO3 concentration fluid) ZnO NPs additives were compared for a range of shear rates from 1 to 500 Sec-1 at different temperatures from 25 °C to 75 °C to visualize modifications in viscosity values after the addition of NPs additives. The rheology in terms of viscosity was higher for the fluid with 1% dispersed ZnO NPs additives at all temperatures for the entire range of shear rate values. Additionally, rheological correlation function models were derived for the synthesized fluids using statistical analysis methods. Subsequently, Herschel-Bulkley models were developed for optimum fluids depending on rheological correlation models. In the last section of the study, the pressure-drop estimation method is described using given group equations for laminar flow in a pipe depending on Herschel-Bulkley-model parameters have been identified for optimum fluids are consistency, flow index and yield stress values.

Dataset Information

L-selectin-mediated lymphocyte-cancer cell interactions under low fluid shear conditions.

Publications

L-selectin-mediated lymphocyte-cancer cell interactions under low fluid shear conditions.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets