Intercellular communication is critical for integrating complex signals in multicellular eukaryotes. Vascular endothelial cells and T lymphocytes closely interact during the recirculation and trans-endothelial migration of T cells. In addition to direct cell-cell contact, we show that T cell derived extracellular vesicles can interact with endothelial cells and modulate their cellular functions. Thrombospondin-1 and its receptor CD47 are expressed on exosomes/ectosomes derived from T cells, and these extracellular vesicles are internalized and modulate signaling in both T cells and endothelial cells. Extracellular vesicles released from cells expressing or lacking CD47 differentially regulate activation of T cells induced by engaging the T cell receptor. Similarly, T cell-derived extracellular vesicles modulate endothelial cell responses to vascular endothelial growth factor and tube formation in a CD47-dependent manner. Uptake of T cell derived extracellular vesicles by recipient endothelial cells globally alters gene expression in a CD47-dependent manner. CD47 also regulates the mRNA content of extracellular vesicles in a manner consistent with some of the resulting alterations in target endothelial cell gene expression. Therefore, the thrombospondin-1 receptor CD47 directly or indirectly regulates intercellular communication mediated by the transfer of extracellular vesicles between vascular cells. More than 2.5 million Americans suffer from burn injuries annually, and burn management is a major public health problem. Treatments have been developed to manage wound injuries employing skin grafts, various dressings and topical and systemic agents. However, these often achieve limited degrees of success. We previously reported that targeting the interaction of thrombospondin-1 with its signaling receptor CD47 or deletion of the genes encoding either of these proteins in mice improves recovery from soft tissue ischemic injuries as well as tissue injuries caused by ionizing radiation. We now demonstrate that the absence of CD47 improves the rate of wound closure for a focal dermal second-degree thermal injury, whereas lack of thrombospondin-1 initially delays wound closure compared to healing in wild type mice. Doppler analysis of the wounded area showed increased blood flow in both CD47 and thrombospondin-1 null mice. Accelerated wound closure in the CD47 null mice was associated with increased fibrosis as demonstrated by a 4-fold increase in collagen fraction. Wound tissue of CD47 null mice showed increased thrombospondin-1 mRNA and protein expression and TGF-beta1 mRNA levels. Activation of latent TGF-beta1 was increased in thermally injured CD47-null tissue as assessed by phosphorylation of the TGF-beta1 receptor-regulated transcription factors SMAD-2 and -3. Overall these results indicate that targeting CD47 may improve the speed of healing thermal injuries, but some level of CD47 expression may be required to limit the long term TGF-beta1-dependent fibrosis of these wounds.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
1ZIASC009172-26
Application #
8938400
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
26
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Clinical Sciences
Department
Type
DUNS #
City
State
Country
Zip Code
Sipes, John M; Murphy-Ullrich, Joanne E; Roberts, David D (2018) Thrombospondins: Purification of human platelet thrombospondin-1. Methods Cell Biol 143:347-369
Kaur, Sukhbir; Elkahloun, Abdel G; Arakelyan, Anush et al. (2018) CD63, MHC class 1, and CD47 identify subsets of extracellular vesicles containing distinct populations of noncoding RNAs. Sci Rep 8:2577
Roberts, David D; Kaur, Sukhbir; Isenberg, Jeffrey S (2017) Regulation of cellular redox signaling by matricellular proteins in vascular biology, immunology, and cancer. Antioxid Redox Signal :
Stein, Erica V; Miller, Thomas W; Ivins-O'Keefe, Kelly et al. (2016) Secreted Thrombospondin-1 Regulates Macrophage Interleukin-1? Production and Activation through CD47. Sci Rep 6:19684
Kaur, Sukhbir; Roberts, David D (2016) Divergent modulation of normal and neoplastic stem cells by thrombospondin-1 and CD47 signaling. Int J Biochem Cell Biol 81:184-194
Soto-Pantoja, D R; Sipes, J M; Martin-Manso, G et al. (2016) Dietary fat overcomes the protective activity of thrombospondin-1 signaling in the Apc(Min/+) model of colon cancer. Oncogenesis 5:e230
Cook, Katherine L; Soto-Pantoja, David R; Clarke, Pamela A G et al. (2016) Endoplasmic Reticulum Stress Protein GRP78 Modulates Lipid Metabolism to Control Drug Sensitivity and Antitumor Immunity in Breast Cancer. Cancer Res 76:5657-5670
Soto-Pantoja, David R; Kaur, Sukhbir; Roberts, David D (2015) CD47 signaling pathways controlling cellular differentiation and responses to stress. Crit Rev Biochem Mol Biol 50:212-30
Lessey-Morillon, Elizabeth C; Roberts, David D (2015) Thrombospondin-1: an extracellular message delivered by macrophages that promotes aortic aneurysms. Circ Res 117:113-5
Kaur, Sukhbir; Schwartz, Anthony L; Miller, Thomas W et al. (2015) CD47-dependent regulation of H?S biosynthesis and signaling in T cells. Methods Enzymol 555:145-68

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