Differential Surface Expression of ADAM10 and ADAM17 on Human T Lymphocytes and Tumor Cells

Abstract

A disintegrin and metalloproteases (ADAMs) have been implicated in many processes controlling organismic development and integrity. Important substrates of ADAM proteases include growth factors, cytokines and their receptors and adhesion proteins. The inducible but irreversible cleavage of their substrates alters cell-cell communication and signaling. The crucial role of ADAM proteases (e.g. ADAM10 and 17) for mammalian development became evident from respective knockout mice, that displayed pre- or perinatal lethality with severe defects in many organs and tissues. Although many substrates for these two ADAM proteases were identified over the last decade, the regulation of their surface appearance, their enzymatic activity and their substrate specificity are still not well understood. We therefore analyzed the constitutive and inducible surface expression of ADAM10 and ADAM17 on a variety of human T cell and tumor cell lines. We demonstrate that ADAM10 is constitutively present at comparably high levels on the majority of the tested cell types. Stimulation with phorbol ester and calcium ionophore does not significantly alter the amount of surface ADAM10, except for a slight down-regulation from T cell blasts. Using FasL shedding as a readout for ADAM10 activity, we show that PKC activation and calcium mobilization are both prerequisite for activation of ADAM10 resulting in a production of soluble FasL. In contrast to ADAM10, the close relative ADAM17 is detected at only low levels on unstimulated cells. ADAM17 surface expression on T cell blasts is rapidly induced by stimulation. Since this inducible mobilization of ADAM17 is sensitive to inhibitors of actin filament formation, we propose that ADAM17 but not ADAM10 is prestored in a subcellular compartment that is transported to the cell surface in an activation- and actin-dependent manner.

Soluble T Cell Immunoglobulin Mucin Domain 3 Is Shed from CD8 + T Cells by the Sheddase ADAM10, Is Increased in Plasma during Untreated HIV Infection, and Correlates with HIV Disease Progression

“…Indeed, high expression levels of some coinhibitory receptors (LAG-3 and Tim-3) on the surface of exhausted cells may be a result of accumulation due to lack of shedding. While shedding may improve T cell responses, it may also contribute to chronic immune activation and progression to AIDS, particularly if there is viral epitope escape (44). While our results suggest that sTim-3 correlates with HIV disease progression, it is still unclear how Tim-3 shedding or sTim-3 itself affects immune responses.…”

“…1). ADAM10 is stimulated after successful T cell activation (44). This suggests that Tim-3 ϩ cells are able to undergo proximal TCR signaling, enough to induce effector function and activate ADAM10 to induce Tim-3 shedding.…”

“…While ADAM10/ADAM17-mediated shedding requires signaling induced by TCR (44), it is unclear what TCR signaling threshold is required for shedding and whether exhausted T cells can shed coinhibitory receptors. Indeed, high expression levels of some coinhibitory receptors (LAG-3 and Tim-3) on the surface of exhausted cells may be a result of accumulation due to lack of shedding.…”

T‐cell regulation through a basic suppressive mechanism targeting low‐density lipoprotein receptor‐related protein 1

“…ADAM10 and its close homologue ADAM17 are sheddases that might be responsible for the results in Figs 1 and 2 as they are expressed in T cells, 30 cause shedding of LRP1 in non-lymphoid cells, and represent a general shedding machinery for membrane proteins. [31][32][33] Figure 3(a) shows that LRP1 was detectable in the culture medium of T cells and that GM6001 (10 lM) and the ADAM10 inhibitor GI254023X (5 lM) reduced the appearance of LRP1 in the medium.…”

Human NOTCH2 Is Resistant to Ligand-independent Activation by Metalloprotease Adam17

“…Because both cleavages lead to presenilin-dependent intramembranous cleavage and transcriptional activation it is not clear yet why both pathways exist. One possible explanation might be that the subcellular localization differs between Adam10 and Adam17 and that Notch receptors follow different secretory routes depending on the type of stimulus (32). If true, this would provide a therapeutic option of controlling ligand-independent signaling in diseases such as cancer.…”