Proteolytic Regulation of the Urokinase Receptor/CD87 on Monocytic Cells by Neutrophil Elastase and Cathepsin G

Beaufort, Nathalie; Leduc, Dominique; Rousselle, Jean-Claude; Magdolen, Viktor; Luther, Thomas; Namane, Abdelkader; Chignard, Michel; Pidard, Dominique

doi:10.4049/jimmunol.172.1.540

Cited by 70 publications

(78 citation statements)

References 61 publications

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“…From the inhibitor data, we propose cathepsin G and chymotrypsin as candidates for the proteases that cleave uPAR, because both would be inhibited by AEBSF and chymostatin. Furthermore, both cleave uPAR in the D1D2 linker region at tyrosine 87 (Ploug et al, 1994, Beaufort et al, 2004 corresponding to a mutated site in the noncleavable uPAR construct. Expression of this noncleavable construct also prevented myofibroblast differentiation.…”

Section: Discussionmentioning

confidence: 99%

Urokinase Receptor Cleavage: A Crucial Step in Fibroblast-to-Myofibroblast Differentiation

Bernstein¹,

Twining

Warejcka

et al. 2007

MBoC

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Fibroblasts migrate into and repopulate connective tissue wounds. At the wound edge, fibroblasts differentiate into myofibroblasts, and they promote wound closure. Regulated fibroblast-to-myofibroblast differentiation is critical for regenerative healing. Previous studies have focused on the role in fibroblasts of urokinase plasmingen activator/urokinase plasmingen activator receptor (uPA/uPAR), an extracellular protease system that promotes matrix remodeling, growth factor activation, and cell migration. Whereas fibroblasts have substantial uPA activity and uPAR expression, we discovered that cultured myofibroblasts eventually lost cell surface uPA/uPAR. This led us to investigate the relevance of uPA/uPAR activity to myofibroblast differentiation. We found that fibroblasts expressed increased amounts of full-length cell surface uPAR (D1D2D3) compared with myofibroblasts, which had reduced expression of D1D2D3 but increased expression of the truncated form of uPAR (D2D3) on their cell surface. Retaining full-length uPAR was found to be essential for regulating myofibroblast differentiation, because 1) protease inhibitors that prevented uPAR cleavage also prevented myofibroblast differentiation, and 2) overexpression of cDNA for a noncleavable form of uPAR inhibited myofibroblast differentiation. These data support a novel hypothesis that maintaining full-length uPAR on the cell surface regulates the fibroblast to myofibroblast transition and that down-regulation of uPAR is necessary for myofibroblast differentiation. INTRODUCTIONMyofibroblast differentiation from fibroblasts is a critical component of the healing process. Regenerative healing (without scarring) results from the successful execution of what have been characterized as three distinct phases of wound healing. In the first phase, fibroblasts that migrate into the wound secrete proteases, extracellular matrix (ECM) molecules, and growth factors. In the second phase, fibroblasts differentiate into nonmotile, wound-contracting myofibroblasts that also secrete ECM proteins and remodel the ECM (Jester et al., 1995;Mohan et al., 2003;Netto et al., 2005). In the third phase, after wound closure, myofibroblasts usually disappear by apoptosis (Desmouliere et al., 1995). Pathological states such as hypertrophic scars, liver cirrhosis, idiopathic lung fibrosis, and glomerulosclerosis are characterized by the persistence of myofibroblasts, which contribute to disease progression by overproduction of ECM and by excessive contraction (Desmouliere et al., 2003;Gabbiani, 2003).To better understand the molecular basis for the fibroblast to myofibroblast transition, we have focused on the role of the urokinase plasmingen activator (uPA) pathway during wound healing. uPA is an extracellular serine protease that binds to its receptor, uPAR, and generates plasmin from plasminogen at the cell-matrix interface. Plasmin is a broadspectrum protease that not only cleaves fibrin and other ECM proteins but also promotes cell migration by activating matrix-sequestered metallopr...

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Section: Discussionmentioning

confidence: 99%

Urokinase Receptor Cleavage: A Crucial Step in Fibroblast-to-Myofibroblast Differentiation

Bernstein¹,

Twining

Warejcka

et al. 2007

MBoC

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“…Other proteases cleave the linker region producing slightly different amino termini (Høyer-Hansen et al, 1992, 1997Ragno et al, 1998;Sidenius et al, 2000;Koolwijk et al, 2001;Andolfo et al, 2002;Beaufort et al, 2004). The soluble form of D2D3 (s-D2D3) produced by uPA, in particular its AVTYSRSRY amino-terminal sequence, is a ligand for FPRL1 that induces chemotaxis .…”

Section: Introductionmentioning

confidence: 99%

An Uncleavable uPAR Mutant Allows Dissection of Signaling Pathways in uPA-dependent Cell Migration

Mazzieri

D’Alessio

Kenmoe

et al. 2006

MBoC

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Urokinase-type plasminogen activator (uPA) binding to uPAR induces migration, adhesion, and proliferation through multiple interactions with G proteins-coupled receptor FPRL1, integrins, or the epidermal growth factor (EGF) receptor (EGFR). At least two forms of uPAR are present on the cell surface: full-length and cleaved uPAR, each specifically interacting with one or more transmembrane proteins. The connection between these interactions and the effects on the signaling pathways activation is not clear. We have exploited an uPAR mutant (hcr, human cleavage resistant) to dissect the pathways involved in uPA-induced cell migration. This mutant is not cleaved by proteases, is glycosylphosphatidylinositol anchored, and binds uPA with a normal K d . Both wild-type (wt) and hcr-uPAR are able to mediate uPA-induced migration, are constitutively associated with the EGFR, and associate with ␣3␤1 integrin upon uPA binding. However, they engage different pathways in response to uPA. wt-uPAR requires both integrins and FPRL1 to mediate uPA-induced migration, and association of wt-uPAR to ␣3␤1 results in uPAR cleavage and extracellular signal-regulated kinase (ERK) activation. On the contrary, hcr-uPAR does not activate ERK and does not engage FPRL1 or any other G protein-coupled receptor, but it activates an alternative pathway initiated by the formation of a triple complex (uPAR-␣3␤1-EGFR) and resulting in the autotyrosine phosphorylation of EGFR. INTRODUCTIONThe serine protease urokinase-type plasminogen activator (uPA) and its high-affinity cell surface receptor (uPAR) play an important role in a number of physiological as well as pathological extracellular degradation processes, where cell migration is required, such as inflammatory responses and tumor invasion (Blasi and Carmeliet, 2002). uPAR was first identified as a major player in the regulation of pericellular proteolysis by modulating and concentrating the uPA activity at the required sites of the cell surface . However, new evidence revealed that uPA binding to uPAR also induces proteolysis-dependent and -independent intracellular signaling affecting cell adhesion, migration, and proliferation in a variety of cells (Chapman, 1997;Ossowski and Aguirre-Ghiso, 2000;Preissner et al., 2000;Blasi and Carmeliet, 2002;Kjøller, 2002).uPAR is a heavily glycosylated glycosylphosphatidylinositol (GPI)-anchored protein formed by three cysteine-rich LY6-like extracellular domains (LU domains D1, D2, and D3) connected by short linker regions (Ploug and Ellis, 1994). The three consecutive three-finger domains of uPAR are organized in an almost circular manner and generate a deep internal cavity for the interaction with uPA. The receptor-binding domain of uPA is engaged in this central cavity, leaving the whole external surface available for other interactions (Llinas et al., 2005). Identified interactors include signaling molecules such as various integrins, the G protein-coupled receptor FPRL1, the epidermal growth factor (EGF) receptor (EGFR), the mannose-6-phosphate recep...

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“…Proteolytic cleavage sites are found between the DI and DII units of uPAR and at the GPI-anchor, rendering three possible soluble forms (full length DI-DIII, DIIDIII and DI, respectively) as well as two membrane-bound variants (full length and DIIDIII) (Figure 1). Enzymes responsible for cleavage of suPAR are uPA itself [40,41], matrix metalloproteinases (MMPs) 3, 12, 19 and 25 [41], GPI-specific phospholipase D [42], neutrophil elastase [43], plasmin [40,41,44] and cathepsin G [43], of which the two latter enzymes are capable of cleaving at both sites ( Figure 1). Factors that have been shown to induce suPAR shedding in an indirect way are cell-cell contact per se [45,46], presence of pro-inflammatory cytokines [25,47], bacterial lipopolysaccharide [46] and growth factors [47].…”

Section: Supar: Distribution Structure and Functionmentioning

confidence: 99%

“…The biological functions of the different suPAR forms have not been fully revealed. DI remains particularly obscure from a mechanistic perspective: it is found in urine [50], but remains undetectable in blood and other body fluids, possibly because of rapid serine proteinase-dependent degradation [43]. The DIIDIII fragment has distinct chemotactic properties due to a SRSRY motif in the linker region between the DI and DII domains that is exposed upon cleavage [51].…”

Section: Supar: Distribution Structure and Functionmentioning

confidence: 99%

Soluble urokinase plasminogen activator receptor—A valuable biomarker in systemic lupus erythematosus?

Enocsson¹,

Sjöwall²,

Wetterö³

2015

Clinica Chimica Acta

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The expression of uPAR is mainly regulated by growth factors and pro-inflammatory cytokines like basic fibroblast growth factor, epidermal growth factor, tumor necrosis factor, interleukin ( suPAR as a clinical marker of inflammation and organ damagePlasma membrane expression of uPAR as well as the levels of circulating suPAR have been investigated in relation to a broad range of conditions and suPAR has been referred to as a "molecular crystal ball" due to its prognostic value in diseases like tuberculosis, HIV, sepsis and cancer [2,6,13,26,58,59]. Further, it has been reported that it reflects overall immune activation and systemic inflammation [2]. suPAR has also emerged as a potential biomarker of fibrosis in chronic liver diseases of diverse etiology [10,11,[60][61][62].Recently, suPAR attracted significant attention in primary focal segmental glomerulosclerosis (FSGS). data from this pilot study revealed significantly higher suPAR levels among patients with moderately or highly elevated SDI after study inclusion, compared to patients without SDI increase (Figure 2).Furthermore, there were higher death rates among patients in the two groups with SDI increase (Figure 2). However, it is well known that present organ damage predicts further organ damage [17,100], and thus, adjustment for SDI at baseline should be performed to reduce the risk of bias. A stepwise linear multiple regression analysis was therefore performed to evaluate the impact of suPAR on future SDI increase. After adjusting for age, sex and SDI at study inclusion, we found suPAR levels to have a significant impact on future SDI increase (p = 0.005, standardized β = 0.20) whereas SDI at study inclusion was excluded from the model. Since recent studies have revealed an inverse correlation between serum suPAR and glomerular filtration [67,68,96], we also included estimated glomerular filtration (eGFR) (calculated by the 4-variable Modification of Diet in Renal Disease StudyGroup formula [101]) in the analysis, but eGFR was not retained in the model. From these results, we suggest that suPAR can actually predict organ damage independent of present SDI score or eGFR, but that a prospective study examining the association between suPAR levels at the time of diagnosis with future SDI would be preferable.In line with these findings, elevated suPAR levels have previously been demonstrated to associate with the risk of developing cancer, cardiovascular disease and type 2 diabetes later in life in the general population [7]. Importantly, these associations were independent of CRP, which is known for its predictive value in cardiovascular disease [7,102].7 Potential roles of suPAR in SLE pathogenesisAssessment of circulating suPAR levels at the clinical laboratory could possibly become a future way to estimate organ damage in SLE, and suPAR would be an even more appealing biomarker candidate if the levels could be mechanistically linked to the disease. The pathogenesis of SLE is notoriously complex and not fully understood, but includes disturbances in t...

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Proteolytic Regulation of the Urokinase Receptor/CD87 on Monocytic Cells by Neutrophil Elastase and Cathepsin G

Cited by 70 publications

References 61 publications

Urokinase Receptor Cleavage: A Crucial Step in Fibroblast-to-Myofibroblast Differentiation

Urokinase Receptor Cleavage: A Crucial Step in Fibroblast-to-Myofibroblast Differentiation

An Uncleavable uPAR Mutant Allows Dissection of Signaling Pathways in uPA-dependent Cell Migration

Soluble urokinase plasminogen activator receptor—A valuable biomarker in systemic lupus erythematosus?

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