Engineering Tools for Studying the Interplay Between Mechanics and Biology in Lymphatic Lipid Transport

2010 ◽  
Author(s):  
J. Brandon Dixon
Keyword(s):  
Immune Cell ◽  
Mechanical Load ◽  
Contractile Function ◽  
Lymphatic Vessels ◽  
Dietary Lipid ◽  
The Body ◽  
Lipid Transport ◽  
Cell Trafficking

The lymphatic vasculature extends through most tissues of the body and plays an essential role in maintaining fluid balance, immune cell trafficking, and lipid transport. Nearly all dietary lipid is transported from the intestine to the circulation via the lymphatic system in the form of triglyceride-rich lipoproteins called chylomicrons. This process can be described through two different mechanisms: 1) entry of the chylomicron into the initial lymphatic vessels of the small intestine, known as lacteals, and 2) the transport of these chylomicrons through the larger collecting lymphatics by a complex and coordinated system of individual contracting vessel units (lymphangions) and valve leaflets. We describe here a set of in vitro and in vivo tools we have developed to study the mechanisms that modulate lipid transport under these two different paradigms and show how these tools are uncovering important biological features involved in these mechanisms. Lymphatic pump function is known to be sensitive to the mechanical load on the vessel as the contractility of isolated vessels has been shown to be both shear and stretch sensitive [1], yet whether these mechanisms are important in regulating contractile function in vivo remains uncertain.

scholarly journals Cellular MR Imaging

2005 ◽  
Vol 4 (3) ◽  
pp. 153535002005051 ◽  
Author(s):  
Michel Modo ◽  
Mathias Hoehn ◽  
Jeff W.M. Bulte
Keyword(s):  
Mr Imaging ◽  
Contrast Agents ◽  
Immune Cell ◽  
Late Phase ◽  
Superparamagnetic Iron Oxide ◽  
Cell Trafficking ◽  
Macrophage Activity ◽  
Active Research

Cellular MR imaging is a young field that aims to visualize targeted cells in living organisms. In order to provide a different signal intensity of the targeted cell, they are either labeled with MR contrast agents in vivo or prelabeled in vitro. Either (ultrasmall) superparamagnetic iron oxide [(U)SPIO] particles or (polymeric) paramagnetic chelates can be used for this purpose. For in vivo cellular labeling, Gd3+- and Mn2+- chelates have mainly been used for targeted hepatobiliary imaging, and (U)SPIO-based cellular imaging has been focused on imaging of macrophage activity. Several of these magneto-pharmaceuticals have been FDA-approved or are in late-phase clinical trials. As for prelabeling of cells in vitro, a challenge has been to induce a sufficient uptake of contrast agents into nonphagocytic cells, without affecting normal cellular function. It appears that this issue has now largely been resolved, leading to an active research on monitoring the cellular biodistribution in vivo following transplantation or transfusion of these cells, including cell migration and trafficking. New applications of cellular MR imaging will be directed, for instance, towards our understanding of hematopoietic (immune) cell trafficking and of novel guided (stem) cell-based therapies aimed to be translated to the clinic in the future.

scholarly journals Migration ofAntigen-Specific T Cells Away from CXCR4-Binding Human ImmunodeficiencyVirus Type 1gp120

2004 ◽  
Vol 78 (10) ◽  
pp. 5184-5193 ◽  
Author(s):  
Diana M. Brainard ◽  
William G. Tharp ◽  
Elva Granado ◽  
Nicholas Miller ◽  
Alicja K. Trocha ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Cell ◽  
Active Movement ◽  
Target Cells ◽  
Cell Mediated Immunity ◽  
Cell Trafficking ◽  
Hiv 1

ABSTRACT Cell-mediated immunity depends in part on appropriate migration and localization of cytotoxic T lymphocytes (CTL), a process regulated by chemokines and adhesion molecules. Many viruses, including human immunodeficiency virus type 1 (HIV-1), encode chemotactically active proteins, suggesting that dysregulation of immune cell trafficking may be a strategy for immune evasion. HIV-1 gp120, a retroviral envelope protein, has been shown to act as a T-cell chemoattractant via binding to the chemokine receptor and HIV-1 coreceptor CXCR4. We have previously shown that T cells move away from the chemokine stromal cell-derived factor 1 (SDF-1) in a concentration-dependent and CXCR4 receptor-mediated manner. Here, we demonstrate that CXCR4-binding HIV-1 X4 gp120 causes the movement of T cells, including HIV-specific CTL, away from high concentrations of the viral protein. This migratory response is CD4 independent and inhibited by anti-CXCR4 antibodies and pertussis toxin. Additionally, the expression of X4 gp120 by target cells reduces CTL efficacy in an in vitro system designed to account for the effect of cell migration on the ability of CTL to kill their target cells. Recombinant X4 gp120 also significantly reduced antigen-specific T-cell infiltration at a site of antigen challenge in vivo. The repellant activity of HIV-1 gp120 on immune cells in vitro and in vivo was shown to be dependent on the V2 and V3 loops of HIV-1 gp120. These data suggest that the active movement of T cells away from CXCR4-binding HIV-1 gp120, which we previously termed fugetaxis, may provide a novel mechanism by which HIV-1 evades challenge by immune effector cells in vivo.

Characterization of Near-Infrared Functional Lymphatic Imaging in the Rat Tail Model

2013 ◽  
Author(s):  
Michael Weiler ◽  
J. Brandon Dixon
Keyword(s):  
Near Infrared ◽  
Immune Cell ◽  
Imaging Modality ◽  
Lymphatic Vessels ◽  
The Body ◽  
Cell Trafficking ◽  
Nir Imaging ◽  
Lymphatic Vasculature ◽  
Rat Tail Model ◽  
Lymphatic Imaging

The lymphatic vasculature is present in nearly every tissue of the body to serve essential functions in fluid homeostasis, immune cell trafficking, and lipid transport, and it has been implicated in the progression of several diseases. Despite the critical roles that this system performs, very little is known about the lymphatic vasculature in comparison to the blood vasculature, which can be attributed, in part, to the difficulty associated with imaging lymphatic vessels. With the growing interest in studying lymphatics, near-infrared (NIR) imaging has emerged in the literature as a novel lymphatic imaging modality to simultaneously improve spatial resolution to visualize small initial lymphatics and increase temporal resolution to capture the dynamic lymphatic pump function responsible for fluid propulsion.

scholarly journals Osteocyte Characterization on Polydimethylsiloxane Substrates for Microsystems Applications

2012 ◽  
Vol 16 ◽  
pp. 27-42 ◽  
Author(s):  
Spencer L. York ◽  
Ahmad R. Arida ◽  
Karan S. Shah ◽  
Palaniappan Sethu ◽  
Marnie M. Saunders
Keyword(s):  
Mechanical Load ◽  
Collagen Type I ◽  
Bone Cell ◽  
Culture Conditions ◽  
Substrate Material ◽  
Research Field ◽  
The Body ◽  
Type I

In the body, osteocytes reside in lacunae, lenticular shaped cavities within mineralized bone. These cells are linked to each other and surface-residing osteoblasts via physical channels known as gap junctions. It has been suggested that osteocytes sense mechanical load applied to bone and relay that signal to osteoclasts and osteoblasts. Currentin vitroandin vivomodels of mechanotransduction face temporal and spatial barriers. Recent advances in polydimethylsiloxane (PDMS) based microfabrication techniques may be able to overcome some of these hurdles. However, before the bone research field can effectively utilize microsystems techniques, fundamental groundwork must be completed. This study characterized the behaviour of osteocytes on PDMS coated with collagen type I (CTI) and provides the framework for bone cell mechanotransduction studies using microsystems. The goal was to determine whether osteocytes were adversely affected by the substrate material by comparing their behaviour to a standard glass substrate. In addition, optimal culture conditions and time points for growing osteocytes on PDMS substrates were determined. Results of this study suggested that use of PDMS does not adversely affect osteocyte behaviour. Furthermore, the results demonstrated that osteocytes should be cultured for no less than 72 hours prior to experimentation to allow the establishment and maintenance of phenotypic characteristics. These results completed essential groundwork necessary for further studies regarding osteocytes in microsystems modelling utilizing PDMS.

scholarly journals Adaptation of mesenteric lymphatic vessels to prolonged changes in transmural pressure

2013 ◽  
Vol 305 (2) ◽  
pp. H203-H210 ◽  
Author(s):  
R. M. Dongaonkar ◽  
T. L. Nguyen ◽  
C. M. Quick ◽  
J. Hardy ◽  
G. A. Laine ◽  
...  
Keyword(s):  
Lymphatic Vessel ◽  
Contractile Function ◽  
Lymphatic Vessels ◽  
Transmural Pressure ◽  
In Vitro Studies ◽  
Pressure Increase ◽  
Adaptive Responses

In vitro studies have revealed that acute increases in transmural pressure increase lymphatic vessel contractile function. However, adaptive responses to prolonged changes in transmural pressure in vivo have not been reported. Therefore, we developed a novel bovine mesenteric lymphatic partial constriction model to test the hypothesis that lymphatic vessels exposed to higher transmural pressures adapt functionally to become stronger pumps than vessels exposed to lower transmural pressures. Postnodal mesenteric lymphatic vessels were partially constricted for 3 days. On postoperative day 3, constricted vessels were isolated, and divided into upstream (UP) and downstream (DN) segment groups, and instrumented in an isolated bath. Although there were no differences between the passive diameters of the two groups, both diastolic diameter and systolic diameter were significantly larger in the UP group than in the DN group. The pump index of the UP group was also higher than that in the DN group. In conclusion, this is the first work to report how lymphatic vessels adapt to prolonged changes in transmural pressure in vivo. Our results suggest that vessel segments upstream of the constriction adapt to become both better fluid conduits and lymphatic pumps than downstream segments.

scholarly journals A Dynamic in vitro BBB Model for the Study of Immune Cell Trafficking into the Central Nervous System

2010 ◽  
Vol 31 (2) ◽  
pp. 767-777 ◽  
Author(s):  
Luca Cucullo ◽  
Nicola Marchi ◽  
Mohammed Hossain ◽  
Damir Janigro
Keyword(s):  
Immune Cells ◽  
Immune Cell ◽  
Cell Trafficking ◽  
In Vitro System ◽  
Immune Cell Trafficking ◽  
The Central Nervous System ◽  
In Vitro Bbb Model ◽  
The Brain

Although there is significant evidence correlating overreacting or perhaps misguided immune cells and the blood–brain barrier (BBB) with the pathogenesis of neuroinflammatory diseases, the mechanisms by which they enter the brain are largely unknown. For this purpose, we revised our humanized dynamic in vitro BBB model (DIV-BBBr) to incorporate modified hollow fibers that now feature transmural microholes (2 to 4 μm Ø) allowing for the transendothelial trafficking of immune cells. As with the original model, this new DIV-BBBr reproduces most of the physiological characteristics of the BBB in vivo. Measurements of transendothelial electrical resistance (TEER), sucrose permeability, and BBB integrity during reversible osmotic disruption with mannitol (1.6 mol/L) showed that the microholes do not hamper the formation of a tight functional barrier. The in vivo rank permeability order of sucrose, phenytoin, and diazepam was successfully reproduced in vitro. Flow cessation followed by reperfusion (Fc/Rp) in the presence of circulating monocytes caused a biphasic BBB opening paralleled by a significant increase of proinflammatory cytokines and activated matrix metalloproteinases. We also observed abluminal extravasation of monocytes but only when the BBB was breached. In conclusion, the DIV-BBBr represents the most realistic in vitro system to study the immune cell trafficking across the BBB.

scholarly journals Csf1r-GCaMP5 Reporter Mice Reveal Immune Cell Communication in Vitro and in Vivo

2021 ◽  
Author(s):  
N Taghdiri ◽  
D Calcagno ◽  
Z Fu ◽  
K Huang ◽  
RH Kohler ◽  
...  
Keyword(s):  
Communication Networks ◽  
Immune Cells ◽  
Immune Cell ◽  
Cell Communication ◽  
Spatiotemporal Dynamics ◽  
The Body ◽  
Excitable Cells ◽  
Communication Events

ABSTRACTInterconnected cells are responsible for emergent functions ranging from cognition in the brain to cyclic contraction in the heart. In electrically excitable cells, methods for studying cell communication are highly advanced, but in non-excitable cells, generalized methods for studying cell communication are less mature. Immune cells have generally been classified as non-excitable cells with diverse pathophysiologic roles that span every tissue in the body, yet little is known about their interconnectedness because assays are destructive and have low temporal resolution. In this work, we hypothesize that non-excitable immune cells are functionally interconnected in previously unrecognized cell communication networks. To test the hypothesis, we created a hematopoietic calcium reporter mouse (Csf1r-Cre × GCaMP5) and non-destructively quantified the spatiotemporal dynamics of intracellular calcium in vitro and in vivo. In vitro, bone marrow derived macrophages calcium reporters reveal that fatal immune stimulatory DNA-sensing induces rapid intercellular communication to neighboring cells. In vivo, using intravital microscopy through a dorsal window chamber in the context of MC38-H2B-mCherry tumors, Csf1r-GCaMP5 reporters exhibit spatiotemporal dynamics consistent with cell communication. We present a theoretical framework and analysis pipeline for identifying spatiotemporal locations of “excess synchrony” of calcium spiking as a means of inferring previously unrecognized cell communication events. Together, these methods provide a toolkit for investigating known and as-yet-undiscovered cell communication events in vitro and in vivo.

Engineered Model of the Intestine Suggests Active Transport of Lipid by Lymphatics

2011 ◽  
Author(s):  
M. F. Faulkner ◽  
J. Brandon Dixon
Keyword(s):  
Molecular Motors ◽  
Immune Cell ◽  
Active Role ◽  
Dietary Lipid ◽  
Lipid Transport ◽  
Cell Trafficking ◽  
Lymphatic Endothelial Cells ◽  
Lipid Trafficking ◽  
Cell Tissue ◽  
Lymphatic Diseases

The lymphatic system has long been thought of as little more than a series of passive ducts as they serve to return fluid and proteins from interstitial spaces back to the blood, provide a route for immune cell trafficking, and transport dietary lipid from the intestine to the blood. Recent evidence has revealed that the lymphatics play an active role in lipid trafficking, and alterations in this function have been correlated with the presence of lymphatic diseases (Dixon, 2010). Here we describe the use of a two-cell, tissue engineered model to explore mechanisms of lipid transport across lymphatic endothelial cells (LEC). Previously this model was demonstrated to recapitulate essential features of the intestinal-lacteal interface with in the mammalian gut (Dixon et al., 2009). With our model we demonstrate, not only that lipid transport across the lymphatics is transcellular and ATP dependent, but also, this mechanism of transport utilizes the molecular motors dynein and kinesin.

scholarly journals Cardiac macrophage subsets differentially regulate lymphatic network remodeling during pressure overload

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mathilde Bizou ◽  
Romain Itier ◽  
Mina Majdoubi ◽  
Dounia Abbadi ◽  
Estelle Pichery ◽  
...  
Keyword(s):  
Immune Cell ◽  
Pressure Overload ◽  
Gene Expression Signature ◽  
Cell Number ◽  
Cell Trafficking ◽  
Macrophage Subpopulations ◽  
Lymphatic Network ◽  
Macrophage Subsets

AbstractThe lymphatic network of mammalian heart is an important regulator of interstitial fluid compartment and immune cell trafficking. We observed a remodeling of the cardiac lymphatic vessels and a reduced lymphatic efficiency during heart hypertrophy and failure induced by transverse aortic constriction. The lymphatic endothelial cell number of the failing hearts was positively correlated with cardiac function and with a subset of cardiac macrophages. This macrophage population distinguished by LYVE-1 (Lymphatic vessel endothelial hyaluronic acid receptor-1) and by resident macrophage gene expression signature, appeared not replenished by CCR2 mediated monocyte infiltration during pressure overload. Isolation of macrophage subpopulations showed that the LYVE-1 positive subset sustained in vitro and in vivo lymphangiogenesis through the expression of pro-lymphangiogenic factors. In contrast, the LYVE-1 negative macrophage subset strongly expressed MMP12 and decreased the endothelial LYVE-1 receptors in lymphatic endothelial cells, a feature of cardiac lymphatic remodeling in failing hearts. The treatment of mice with a CCR2 antagonist during pressure overload modified the proportion of macrophage subsets within the pathological heart and preserved lymphatic network from remodeling. This study reports unknown and differential functions of macrophage subpopulations in the regulation of cardiac lymphatic during pathological hypertrophy and may constitute a key mechanism underlying the progression of heart failure.

IMMU-20. HYDROGEL-CXCL9 VACCINE RESULTS IN MRNA DELIVERY TO DENDRITIC CELLS AND POTENT ANTI-TUMOR RESPONSES IN GBM

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi96-vi96
Author(s):  
Farhad Dastmalchi ◽  
Aida Karachi ◽  
Yusuf Mehkri ◽  
Ashley O’Malley ◽  
Vignesh Subramaniam ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Single Dose ◽  
Nk Cells ◽  
Immune Cell ◽  
Control Group ◽  
Cell Trafficking ◽  
Fat Pad ◽  
Tumor Bearing

Abstract INTRODUCTION Our group and others have shown mRNA-vaccines have significant anti-tumor efficacy in the treatment of brain tumors and are currently being tested in first-in-human trials. To further enhance mRNA delivery, a hydrogel platform was developed with the addition of CXCL9 to promote immune cell trafficking. METHODS We generated the vaccine by utilizing a hydrogel platform. CXCL9 and Nano-mRNA were loaded into the hydrogel. In vitro recruitment of DCs and NK was evaluated by fluorescence microscopy. In vivo recruitment of immune cells was analyzed by flowcytometry after collecting the fat pad, spleen, and tumor samples from KR158b-luc and Gl261-gp100 tumor-bearing animals 3, 5 and 10 days after vaccine delivery. The efficacy of the vaccine was evaluated by measuring overall survival, and tumor growth was measured by IVIS live-imaging. RESULTS Dendritic cells(DCs) and natural killer(NK) cells were able to efficiently migrate within the hydrogel-CXCL9 platform and uptake and express mRNA in vivo. In vitro, the hydrogel-CXCL9 was combined with nanoparticles loaded with total tumor RNA, and the vaccine was delivered to KR-158-luc and GL261-gp100 tumor-bearing animals via mammary fat pad SQ injection. Flow cytometry of the fat pad and draining lymph nodes demonstrated showed significant recruitment of endogenous DCs including inflammatory-DC(P= 0.0035), conventional-DC1(P= 0.0076), pDC(P=0.0028), NK(p= 0.0025 compared to the control group. In two different tumor models, a single dose of the vaccine resulted in significant survival benefits compared to control animals (n=10,P< 0.0001). SQ injection was superior to intracranial injection of the vaccine. Vaccinated animals showed an increased number of antigen-specific CD8 T cells in spleen(P= 0.0001) and tumor-microenvironment(P= 0.0070). CONCLUSION The hydrogel-CXCL9 platform results in efficient delivery of mRNA loaded nanoparticles to endogenous DCs and also causes an upregulation of NK cells with resultant improved survival in murine GBM models including the highly resistant KR158 model with a single dose. Further studies are ongoing.

Sign in / Sign up

Export Citation Format

Share Document