Medical and Research Sections

San Diego, CA, United States

Medical and Research Sections

San Diego, CA, United States
Time filter
Source Type

El Ghazal R.,Medical and Research Sections | Yin X.,Medical and Research Sections | Johns S.C.,Medical and Research Sections | Swanson L.,University of California at San Diego | And 4 more authors.
Neoplasia (New York, N.Y.) | Year: 2016

In cancer, proteoglycans have been found to play roles in facilitating the actions of growth factors, and effecting matrix invasion and remodeling. However, little is known regarding the genetic and functional importance of glycan chains displayed by proteoglycans on dendritic cells (DCs) in cancer immunity. In lung carcinoma, among other solid tumors, tumor-associated DCs play largely subversive/suppressive roles, promoting tumor growth and progression. Herein, we show that targeting of DC glycan sulfation through mutation in the heparan sulfate biosynthetic enzyme N-deacetylase/N-sulfotransferase-1 (Ndst1) in mice increased DC maturation and inhibited trafficking of DCs to draining lymph nodes. Lymphatic-driven DC migration and chemokine (CCL21)-dependent activation of a major signaling pathway required for DC migration (as measured by phospho-Akt) were sensitive to Ndst1 mutation in DCs. Lewis lung carcinoma tumors in mice deficient in Ndst1 were reduced in size. Purified CD11c+ cells from the tumors, which contain the tumor-infiltrating DC population, showed a similar phenotype in mutant cells. These features were replicated in mice deficient in syndecan-4, the major heparan sulfate proteoglycan expressed on the DC surface: Tumors were growth-impaired in syndecan-4-deficient mice and were characterized by increased infiltration by mature DCs. Tumors on the mutant background also showed greater infiltration by NK cells and NKT cells. These findings indicate the genetic importance of DC heparan sulfate proteoglycans in tumor growth and may guide therapeutic development of novel strategies to target syndecan-4 and heparan sulfate in cancer. Published by Elsevier Inc.

Johns S.C.,Medical and Research Sections
Circulation Research | Year: 2016

RATIONALE:: Lymphatic vessel growth is mediated by major pro-lymphangiogenic factors such as VEGF-C and -D, among other endothelial effectors. Heparan sulfate is a linear polysaccharide expressed on proteoglycan core proteins on cell-membranes and matrix, playing roles in angiogenesis, although little is known regarding any function(s) in lymphatic remodeling in vivo. OBJECTIVE:: To explore the genetic basis and mechanisms whereby heparan sulfate proteoglycans mediate pathologic lymphatic remodeling. METHODS AND RESULTS:: Lymphatic endothelial deficiency in the major heparan sulfate biosynthetic enzyme N-deacetylase/N-sulfotransferase-1 (Ndst1; involved in glycan-chain sulfation) was associated with reduced lymphangiogenesis in pathologic models, including spontaneous neoplasia. Mouse mutants demonstrated tumor-associated lymphatic vessels with apoptotic nuclei. Mutant lymphatic endothelia demonstrated impaired mitogen (Erk) and survival (Akt) pathway signaling as well as reduced VEGF-C mediated protection from starvation-induced apoptosis. Lymphatic endothelial specific Ndst1 deficiency (in Ndst1Prox1 mice) was sufficient to inhibit VEGF-C dependent lymphangiogenesis. Lymphatic heparan sulfate deficiency reduced phosphorylation of the major lymphatic growth receptor VEGFR-3 in response to multiple VEGF-C species. Syndecan-4 was the dominantly expressed heparan sulfate proteoglycan in mouse lymphatic endothelia, and pathologic lymphangiogenesis was impaired in Sdc4(-/-) mice. On the lymphatic cell surface, VEGF-C induced robust association between syndecan-4 and VEGFR-3 which was sensitive to glycan disruption. Moreover, VEGFR-3 mitogen and survival signaling was reduced in the setting of Ndst1 or Sdc4 deficiency. CONCLUSIONS:: These findings demonstrate the genetic importance of heparan sulfate and the major lymphatic proteoglycan syndecan-4 in pathologic lymphatic remodeling. This may introduce novel future strategies to alter pathologic lymphatic-vascular remodeling.Circulation Research is published on behalf of the American Heart Association, Inc., by Wolters Kluwer. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial-NoDervis License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited, the use is noncommercial, and no modifications or adaptations are made. © 2016 American Heart Association, Inc.

Dyer D.P.,University of California at San Diego | Dyer D.P.,University of Glasgow | Salanga C.L.,University of California at San Diego | Johns S.C.,Medical and Research Sections | And 7 more authors.
Journal of Biological Chemistry | Year: 2016

TNF-stimulated gene-6 (TSG-6) is a multifunctional protein secreted in response to pro-inflammatory stimuli by a wide range of cells, including neutrophils, monocytes, and endothelial cells. It has been shown to mediate anti-inflammatory and protective effects when administered in disease models, in part, by reducing neutrophil infiltration. Human TSG-6 inhibits neutrophil migration by binding CXCL8 through its Link module (Link-TSG6) and interfering with the presentation of CXCL8 on cell-surface glycosaminoglycans (GAGs), an interaction that is vital for the function of many chemokines. TSG-6 was also found to interact with chemokines CXCL11 and CCL5, suggesting the possibility that it may function as a broad specificity chemokine-binding protein, functionally similar to those encoded by viruses. This study was therefore undertaken to explore the ability of TSG-6 to regulate the function of other chemokines. Herein, we demonstrate that Link-TSG6 binds chemokines from both the CXC and CC families, including CXCL4, CXCL12, CCL2, CCL5, CCL7, CCL19, CCL21, and CCL27. We also show that the Link-TSG6-binding sites on chemokines overlap with chemokine GAG-binding sites, and that the affinities of Link-TSG6 for these chemokines (KD values 1-85 nM) broadly correlate with chemokine-GAG affinities. Link-TSG6 also inhibits chemokine presentation on endothelial cells not only through a direct interaction with chemokines but also by binding and therefore masking the availability of GAGs. Along with previous work, these findings suggest that TSG-6 functions as a pluripotent regulator of chemokines by modulating chemokine/GAG interactions, which may be a major mechanism by which TSG-6 produces its anti-inflammatory effects in vivo. © 2016, American Society for Biochemistry and Molecular Biology Inc. All rights reserved.

Yin X.,Huaihai Institute of Technology | Yin X.,Medical and Research Sections | Yin X.,University of California at San Diego | Johns S.C.,Medical and Research Sections | And 7 more authors.
Methods in Enzymology | Year: 2016

Interactions between glycosaminoglycans (GAGs) and chemokines play a critical role in multiple physiological and pathological processes, including tumor metastasis and immune-cell trafficking. During our studies examining the genetic importance of the GAG subtype known as heparan sulfate (HS) on lymphatic endothelial cells (LECs), we established a repertoire of methods to assess how HS affects chemokine-mediated cell-cell interactions. In this chapter, we describe methods for monitoring migration and adhesion interactions of dendritic cells (DCs), the most potent antigen-presenting cells, with LECs. We will also report a methodology to assess chemokine-receptor interactions while incorporating approaches to target HS in the system. This includes in situ methods to visualize and quantify direct interactions between chemokines and chemokine receptors on DC surfaces, and how targeting HS produced by LECs or even DCs affects these interactions. These methods enable the mechanistic and functional characterization of GAG-chemokine interactions in cell-based studies that model physiologic interactions ex vivo. They may also be used to obtain novel insights into GAG-mediated biological processes. © 2016 Elsevier Inc. All rights reserved.

Loading Medical and Research Sections collaborators
Loading Medical and Research Sections collaborators