Lymphatic dysfunction impairs antigen-specific immunization, but augments tissue swelling following contact with allergens

The lymph transports tissue-resident dendritic cells (DCs) to regional lymph nodes (LNs), having important roles in immune function. The biological effects on tissue inflammation following lymphatic flow obstruction in vivo, however, are not fully known. In this study, we investigated the role of the lymphatic system in contact hypersensitivity (CHS) responses using k-cyclin transgenic (kCYC(+/-)) mice, which demonstrate severe lymphatic dysfunction. kCYC(+/-) mice showed enhanced ear swelling to both DNFB and FITC, as well as stronger irritant responses to croton oil compared with wild-type littermates. Consistently, challenged ears of kCYC(+/-) mice exhibited massive infiltrates of inflammatory cells. In contrast, DC migration to regional LNs, drainage of cell-free antigen to LNs, antigen-specific IFN-γ production, and lymphocyte proliferation were impaired during the sensitization phase of CHS in kCYC(+/-) mice. Transfer experiments using lymphocytes from sensitized mice and real-time PCR analysis of cytokine expression using challenged ear revealed that ear swelling was enhanced because of impaired lymphatic flow. Collectively, we conclude that insufficient lymphatic drainage augments apparent inflammation to topically applied allergens and irritants. The findings add insight into the clinical problem of allergic and irritant contact dermatitis that commonly occurs in humans with peripheral edema of the lower legs.

Alterations in maternal and fetal heart functions accompany failed spiral arterial remodeling in pregnant mice

OBJECTIVE

Our goal was to define mechanisms that protect murine pregnancies deficient in spiral arterial remodeling from hypertension, hypoxia, and intrauterine growth restriction.

STUDY DESIGN

Microultrasound analyses were conducted on virgin, gestation day 2, 4, 7, 9, 10, 12, 14, 16, 18, and postpartum BALB/c (wild type) mice and BALB/c-Rag2(-/-)/Il2rg(-/-) mice, an immunodeficient strain lacking spiral arterial remodeling.

RESULTS

Rag2(-/-)/Il2rg(-/-) dams had normal spiral arterial flow velocities, greatly elevated uterine artery flow velocities between gestational day 10-16 and smaller areas of placental flow from gestational day 14 to term than controls. Maternal heart weight and output increased transiently. Conceptus alterations included higher flow velocities in the umbilical-placental circulation that became normal before term and bradycardia persistent to term.

CONCLUSION

Transient changes in maternal heart weight and function accompanied by fetal circulatory changes successfully compensate for deficient spiral arterial modification in mice. Similar compensations may contribute to the elevated risk for cardiovascular diseases seen in women and their children who experience preeclamptic pregnancies.

Afferent lymph-derived T cells and DCs use different chemokine receptor CCR7-dependent routes for entry into the lymph node and intranodal migration

Little is known about the molecular mechanisms that determine the entry into the lymph node and intranodal positioning of lymph-derived cells. By injecting cells directly into afferent lymph vessels of popliteal lymph nodes, we demonstrate that lymph-derived T cells entered lymph-node parenchyma mainly from peripheral medullary sinuses, whereas dendritic cells (DCs) transmigrated through the floor of the subcapsular sinus on the afferent side. Transmigrating DCs induced local changes that allowed the concomitant entry of T cells at these sites. Signals mediated by the chemokine receptor CCR7 were absolutely required for the directional migration of both DCs and T cells into the T cell zone but were dispensable for the parenchymal entry of lymph-derived T cells and dendrite probing of DCs. Our findings provide insight into the molecular and structural requirements for the entry into lymph nodes and intranodal migration of lymph-derived cells of the immune system.

Sources and signals regulating type I interferon production: lessons learned from cytomegalovirus

Type I interferons (IFN-αβ) are pleiotropic cytokines critical for antiviral host defense, and the timing and magnitude of their production involve a complex interplay between host and pathogen factors. Mouse cytomegalovirus (a β-herpesvirus) is a persistent virus that induces a biphasic IFN-αβ response during the first days of infection. The cell types and molecular mechanisms governing these 2 phases are unique, with splenic stromal cells being a major source of initial IFN-αβ, requiring communication with B cells expressing lymphotoxin, a tumor necrosis factor family cytokine. Here we review the factors that regulate this lymphotoxin-IFN-αβ "axis" during cytomegalovirus infection, highlight how stroma-derived IFN-αβ contributes in other models, and discuss how deregulation of this axis can lead to pathology in some settings.

Chemokines in health and disease

Chemokines and their receptors play a key role in development and homeostasis as well as in the pathogenesis of tumors and autoimmune diseases. Chemokines are involved in the implantation of the early conceptus, the migration of subsets of cells during embryonic development, and the overall growth of the embryo. Chemokines also have an important role in the development and maintenance of innate and adaptive immunity. In addition, they play a significant role in wound healing and angiogenesis. When the physiological role of chemokines is subverted or chronically amplified, disease often follows. Chemokines are involved in the pathobiology of chronic inflammation, tumorigenesis and metastasis, as well as autoimmune diseases. This article reviews the role of chemokines and their receptors in normal and disease processes and the potential for using chemokine antagonists for appropriate targeted therapy.

Lymph node stroma broaden the peripheral tolerance paradigm

Research into how self-reactive T cells are tolerized in lymph nodes has focused largely on dendritic cells (DCs). We now know that lymph node stromal cells (LNSC) are important mediators of deletional tolerance to peripheral tissue-restricted antigens (PTAs), which are constitutively expressed and presented by LNSCs. Of the major LNSC subsets, fibroblastic reticular cells and lymphatic endothelial cells are known to directly induce tolerance of responding naïve CD8 T cells. The biological outcome of this interaction fills a void otherwise not covered by DCs or thymic stromal cells. These findings, we suggest, necessitate a broadening of peripheral tolerance theory to include steady-state presentation of clinically relevant PTA to naïve CD8 T cells by lymph node-resident stroma.

Synthesis of artificial lymphoid tissue with immunological function

The ability to generate functional artificial lymphoid tissue to induce specific immunity at ectopic sites could offer a potential breakthrough for treatment of diseases such as cancer and severe infection using immunotherapy. Artificial lymphoid tissue could also offer an informative tool to study further lymphoid tissue development and function in vivo. Here, we review the process of secondary and tertiary lymphoid organization, of which an understanding is essential for artificial lymphoid tissue synthesis. Using this knowledge, we consider the combination of cell types, soluble factors and scaffold properties that will enable proper accumulation and organization of lymphocytes into tissue grafts. Recent success in in vivo induction of artificial lymphoid tissue are also considered.

Role of lymphatic vessels in tumor immunity: passive conduits or active participants?

Research in lymphatic biology and cancer immunology may soon intersect as emerging evidence implicates the lymphatics in the progression of chronic inflammation and autoimmunity as well as in tumor metastasis and immune escape. Like the blood vasculature, the lymphatic system comprises a highly dynamic conduit system that regulates fluid homeostasis, antigen transport and immune cell trafficking, which all play important roles in the progression and resolution of inflammation, autoimmune diseases, and cancer. This review presents emerging evidence that lymphatic vessels are active modulators of immunity, perhaps fine-tuning the response to adjust the balance between peripheral tolerance and immunity. This suggests that the tumor-associated lymphatic vessels and draining lymph node may be important in tumor immunity which in turn governs metastasis.

Inhibition of chemokine-glycosaminoglycan interactions in donor tissue reduces mouse allograft vasculopathy and transplant rejection

BACKGROUND

Binding of chemokines to glycosaminoglycans (GAGs) is classically described as initiating inflammatory cell migration and creating tissue chemokine gradients that direct local leukocyte chemotaxis into damaged or transplanted tissues. While chemokine-receptor binding has been extensively studied during allograft transplantation, effects of glycosaminoglycan (GAG) interactions with chemokines on transplant longevity are less well known. Here we examine the impact of interrupting chemokine-GAG interactions and chemokine-receptor interactions, both locally and systemically, on vascular disease in allografts.

METHODOLOGY/PRINCIPAL FINDINGS

Analysis of GAG or CC chemokine receptor 2 (CCR2) deficiency were coupled with the infusion of viral chemokine modulating proteins (CMPs) in mouse aortic allograft transplants (n = 239 mice). Inflammatory cell invasion and neointimal hyperplasia were significantly reduced in N-deacetylase-N-sulfotransferase-1 (Ndst1(f/f)TekCre(+)) heparan sulfate (GAG)-deficient (Ndst1(-/-), p<0.044) and CCR2-deficient (Ccr2(-/-), p<0.04) donor transplants. Donor tissue GAG or CCR2 deficiency markedly reduced inflammation and vasculopathy, whereas recipient deficiencies did not. Treatment with three CMPs was also investigated; Poxviral M-T1 blocks CC chemokine receptor binding, M-T7 blocks C, CC, and CXC GAG binding, and herpesviral M3 binds receptor and GAG binding for all classes. M-T7 reduced intimal hyperplasia in wild type (WT) (Ccr2(+/+), p< or =0.003 and Ccr2(-/-), p

CONCLUSIONS/SIGNIFICANCE

Interruption of chemokine-GAG interactions, even in the absence of chemokine-receptor blockade, is a highly effective approach to reduction of allograft rejection, reducing vascular inflammation and prolonging allograft survival. Although chemokines direct both local and systemic cell migration, interruption of inherent chemokine responses in the donor tissue unexpectedly had a greater therapeutic impact on allograft vasculopathy.

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Key Words Collapse

MESH Headings

• Animals
• Aorta/drug effects
• Aorta/pathology
• Aorta/transplantation
• Cell Movement/drug effects
• Cell Proliferation/drug effects
• Chemokines/metabolism
• Chemokines/pharmacology
• Disease Models, Animal
• Glycosaminoglycans/metabolism
• Graft Rejection/complications
• Graft Rejection/enzymology
• Graft Rejection/immunology
• Hyperplasia
• Inflammation/complications
• Inflammation/pathology
• Kidney Transplantation
• Mice
• Mice, Inbred BALB C
• Mice, Inbred C57BL
• Receptors, CCR2/deficiency
• Receptors, CCR2/metabolism
• Sulfotransferases/deficiency
• Sulfotransferases/metabolism
• Survival Analysis
• Tissue Donors
• Transplantation, Homologous
• Tunica Intima/drug effects
• Tunica Intima/pathology
• Vascular Diseases/complications
• Vascular Diseases/enzymology
• Vascular Diseases/immunology
• Vascular Diseases/pathology
• Viral Proteins/pharmacology

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Grants

• RC1 HL100202 NHLBI NIH HHS
• 1RC1HL100202-01 NHLBI NIH HHS
• MOP 577578 CIHR

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Affiliation(s)

Erbin Dai Vascular Biology Research Group, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada Division of Cardiovascular Medicine, University of Florida, Gainesville, Florida, United States of America Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
Li-Ying Liu Vascular Biology Research Group, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada Division of Cardiovascular Medicine, University of Florida, Gainesville, Florida, United States of America Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
Hao Wang Departments of Medicine and Surgery, and Microbiology and Immunology, The University of Western Ontario, London, Ontario, Canada
Dana McIvor Departments of Medicine and Surgery, and Microbiology and Immunology, The University of Western Ontario, London, Ontario, Canada
Yun ming Sun Vascular Biology Research Group, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada Viron Therapeutics, Inc., London, Ontario, Canada
Colin Macaulay Viron Therapeutics, Inc., London, Ontario, Canada
Elaine King Viron Therapeutics, Inc., London, Ontario, Canada
Ganesh Munuswamy-Ramanujam Vascular Biology Research Group, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada Division of Cardiovascular Medicine, University of Florida, Gainesville, Florida, United States of America Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
Mee Yong Bartee Division of Cardiovascular Medicine, University of Florida, Gainesville, Florida, United States of America Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
Jennifer Williams Division of Cardiovascular Medicine, University of Florida, Gainesville, Florida, United States of America Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
Jennifer Davids Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
Israel Charo Gladstone Institute, San Francisco, California, United States of America
Grant McFadden Departments of Medicine and Surgery, and Microbiology and Immunology, The University of Western Ontario, London, Ontario, Canada Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
Jeffrey D. Esko Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, California, United States of America
Alexandra R. Lucas Vascular Biology Research Group, Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada Departments of Medicine and Surgery, and Microbiology and Immunology, The University of Western Ontario, London, Ontario, Canada Division of Cardiovascular Medicine, University of Florida, Gainesville, Florida, United States of America Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America

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A multichamber fluidic device for 3D cultures under interstitial flow with live imaging: development, characterization, and applications

Interstitial flow is an important biophysical cue that can affect capillary morphogenesis, tumor cell migration, and fibroblast remodeling of the extracellular matrix, among others. Current models that incorporate interstitial flow and that are suitable for live imaging lack the ability to perform multiple simultaneous experiments, for example, to compare effects of growth factors, extracellular matrix composition, etc. We present a nine-chamber radial flow device that allows simultaneous 3D fluidic experiments for relatively long-term culture with live imaging capabilities. Flow velocity profiles were characterized by fluorescence recovery after photobleaching (FRAP) for flow uniformity and estimating the hydraulic conductivity. We demonstrate lymphatic and blood capillary morphogenesis in fibrin gels over 10 days, comparing flow with static conditions as well as the effects of an engineered variant of VEGF that binds fibrin via Factor XIII. We also demonstrate the culture of contractile fibroblasts and co-cultures with tumor cells for modeling the tumor microenvironment. Therefore, this device is useful for studies of capillary morphogenesis, cell migration, contractile cells like fibroblasts, and multicellular cultures, all under interstitial flow.

Transmural flow modulates cell and fluid transport functions of lymphatic endothelium

RATIONALE

Lymphatic transport of peripheral interstitial fluid and dendritic cells (DCs) is important for both adaptive immunity and maintenance of tolerance to self-antigens. Lymphatic drainage can change rapidly and dramatically on tissue injury or inflammation, and therefore increased fluid flow may serve as an important early cue for inflammation; however, the effects of transmural flow on lymphatic function are unknown.

OBJECTIVE

Here we tested the hypothesis that lymph drainage regulates the fluid and cell transport functions of lymphatic endothelium.

METHODS AND RESULTS

Using in vitro and in vivo models, we demonstrated that lymphatic endothelium is sensitive to low levels of transmural flow. Basal-to-luminal flow (0.1 and 1 mum/sec) increased lymphatic permeability, dextran transport, and aquaporin-2 expression, as well as DC transmigration into lymphatics. The latter was associated with increased lymphatic expression of the DC homing chemokine CCL21 and the adhesion molecules intercellular adhesion molecule-1 and E-selectin. In addition, transmural flow induced delocalization and downregulation of vascular endothelial cadherin and PECAM-1 (platelet/endothelial cell adhesion molecule-1). Flow-enhanced DC transmigration could be reversed by blocking CCR7, intercellular adhesion molecule-1, or E-selectin. In an experimental model of lymphedema, where lymphatic drainage is greatly reduced or absent, lymphatic endothelial expression of CCL21 was nearly absent.

CONCLUSIONS

These findings introduce transmural flow as an important regulator of lymphatic endothelial function and suggest that flow might serve as an early inflammatory signal for lymphatics, causing them to regulate transport functions to facilitate the delivery of soluble antigens and DCs to lymph nodes.