Regions involved in binding of urokinase-type-1 inhibitor complex and pro-urokinase to the endocytic alpha 2-macroglobulin receptor/low density lipoprotein receptor-related protein. Evidence that the urokinase receptor protects pro-urokinase against binding to the endocytic receptor.

Nykjær, Anders; Kjøller, Lars; Cohen, Robert; Lawrence, Daniel A.; Garni-Wagner, B. A.; Todd, Robert F.; Zonneveld, Anton Jan van; Gliemann, Jørgen; Andreasen, Peter A.

doi:10.1016/s0021-9258(18)47301-2

Cited by 128 publications

(16 citation statements)

References 42 publications

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“…Our data showing the deleterious effects of the t-PA:PAI1 complex on the neurovasculature provide a novel paradigm that links these events in TBI. Furthermore, since the binding affinity of t-PA for LDLRs is amplified over 300-fold upon complex formation (Nykjaer et al, 1994), we suggest that PAI1 serves as a conduit for t-PA in LDLR signalling and consequent abrogation of neurovascular integrity. It remains to be determined if complex formation between t-PA and other serpins (i.e.…”

Section: Discussionmentioning

confidence: 88%

“…Reports have indicated that t-PA acts as a signal transducer by binding to LDLR-related protein 1 and transcriptionally regulating genes including members of the matrix metalloproteinase (MMP) family (Herz, 2001;Candelario-Jalil et al, 2009). It is also known that free t-PA binds to LDLRs with $300-fold lower affinity than t-PA:serpin complexes suggesting differential signalling capabilities of free and complexed t-PA (Nykjaer et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

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The tissue-type plasminogen activator–plasminogen activator inhibitor 1 complex promotes neurovascular injury in brain trauma: evidence from mice and humans

Sashindranath

Sales

Daglas

et al. 2012

Brain

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The neurovascular unit provides a dynamic interface between the circulation and central nervous system. Disruption of neurovascular integrity occurs in numerous brain pathologies including neurotrauma and ischaemic stroke. Tissue plasminogen activator is a serine protease that converts plasminogen to plasmin, a protease that dissolves blood clots. Besides its role in fibrinolysis, tissue plasminogen activator is abundantly expressed in the brain where it mediates extracellular proteolysis. However, proteolytically active tissue plasminogen activator also promotes neurovascular disruption after ischaemic stroke; the molecular mechanisms of this process are still unclear. Tissue plasminogen activator is naturally inhibited by serine protease inhibitors (serpins): plasminogen activator inhibitor-1, neuroserpin or protease nexin-1 that results in the formation of serpin:protease complexes. Proteases and serpin:protease complexes are cleared through high-affinity binding to low-density lipoprotein receptors, but their binding to these receptors can also transmit extracellular signals across the plasma membrane. The matrix metalloproteinases are the second major proteolytic system in the mammalian brain, and like tissue plasminogen activators are pivotal to neurological function but can also degrade structures of the neurovascular unit after injury. Herein, we show that tissue plasminogen activator potentiates neurovascular damage in a dose-dependent manner in a mouse model of neurotrauma. Surprisingly, inhibition of activity following administration of plasminogen activator inhibitor-1 significantly increased cerebrovascular permeability. This led to our finding that formation of complexes between tissue plasminogen activator and plasminogen activator inhibitor-1 in the brain parenchyma facilitates post-traumatic cerebrovascular damage. We demonstrate that following trauma, the complex binds to low-density lipoprotein receptors, triggering the induction of matrix metalloproteinase-3. Accordingly, pharmacological inhibition of matrix metalloproteinase-3 attenuates neurovascular permeability and improves neurological function in injured mice. Our results are clinically relevant, because concentrations of tissue plasminogen activator: plasminogen activator inhibitor-1 complex and matrix metalloproteinase-3 are significantly elevated in cerebrospinal fluid of trauma patients and correlate with neurological outcome. In a separate study, we found that matrix metalloproteinase-3 and albumin, a marker of cerebrovascular damage, were significantly increased in brain tissue of patients with neurotrauma. Perturbation of neurovascular homeostasis causing oedema, inflammation and cell death is an important cause of acute and long-term neurological dysfunction after trauma. A role for the tissue plasminogen activator-matrix metalloproteinase axis in promoting neurovascular disruption after neurotrauma has not been described thus far. Targeting tissue plasminogen activator: plasminogen activator inhibitor-1 complex signalling or dow...

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Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

The tissue-type plasminogen activator–plasminogen activator inhibitor 1 complex promotes neurovascular injury in brain trauma: evidence from mice and humans

Sashindranath

Sales

Daglas

et al. 2012

Brain

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“…The endosomal guidance protein LRP-1 was shown by Andreasen & colleagues [14] to bind to common protein regions shared by uPA and PAI-1 at the binding site of uPA-PAI-1 [14]. LRP-1 is an endosomal guidance protein that participates in endocytosis of the PAI-1-uPA::uPAR complex at the plasmalemma and internalized as a quaternary complex guiding uPAS endosomal trafficking [14,48]. The proposed drug target (uPA-PAI-1) and the observed 'mis-trafficking' of uPA endosomes by Cmpd10357 and UCD38B differs from other plasmalemmal uPA and PAI-1 antagonists and from anti-cancer cytotoxic mechanisms described for amiloride [41] and hexamethyl amiloride (HMA) [42].…”

Section: Discussionmentioning

confidence: 99%

Intracellular Urokinase uPA-PAl-1 Complex: Disruption by Small Molecule Targets Hypoxically Programmed Glioma Cells

Gorin¹

2018

OAJNN

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Background and ImportanceHigh-grade gliomas (HGGs) are an aggressive group of primary glial brain cancers characterized by rapid, infiltrative growth. The most aggressive of these HGGs, WHO grade 4 astrocytomas, contain spontaneously hypoxic, necrotic, and hemorrhagic tumor domains resulting from rapid proliferation with ineffective neo vascularization. These hypovascularized, tumor regions harbor populations of glioma cells capable of selfrenewal, and tumor regrowth [1] and are resistant to radiation therapy, anti-mitotic agents, and anti-angiogenic therapies [2,3]. These hypoxic cancer cells have been shown to be non-proliferative or minimally proliferative enabling them to survive anti-mitotic drugs, radiation therapy, and anti-angiogenic agents [4]. Conventional therapies and anti-angiogenic therapy has been demonstrated to enrich for 'stem-like' and additional cancer initiating cells, which have been reprogrammed by hypoxicinduced transcription factors, notably HIF2α [5]. Consequently, hypoxic regenerative cancer cells are now recognized as a primary impediment to the successful treatment of highly proliferative cancers due to their roles in resistance, recurrence and metastasis [6,7].

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“…Recombinant 39 kD RAP and rabbit antiserum raised against a recombinant a-chain fragment of LRP! a2-MR (amino acids 2500-2922) have been described before (Nykj~er et al, 1992(Nykj~er et al, , 1994a. Purified LRP/ct2-MR and gp330 were prepared as described previously (Moestrup and Gliemann, 1991;Moestrup et al, 1993a).…”

Section: Reagentsmentioning

confidence: 99%

“…uPA-serpin degradation in various cell types can be inhibited by RAP and by antibodies against the LRP/a2-MR (Nykj~er et al, 1992;Willnow et al, 1992;Herz et al, 1992;Kounnas et al, 1993;Conese et al, 1994). The uPA-PAL1 complex binds to LRP/et2-MR through sites localized in PAI-1, as well as in both the serine protease domain and the A-chain of uPA, indicating the involvement of several independent binding contacts with LRP/et2-MR (Nykj~er et al, 1994a).…”

mentioning

confidence: 99%

alpha-2 Macroglobulin receptor/Ldl receptor-related protein(Lrp)-dependent internalization of the urokinase receptor.

Conese

Nykjær

Petersen

et al. 1995

The Journal of Cell Biology

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191

183

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Abstract. The GPI-anchored urokinase plasminogen activator receptor (uPAR) does not internalize free urokinase (uPA). On the contrary, uPAR-bound complexes of uPA with its serpin inhibitors PAI-1 (plasminogen activator inhibitor type-l) or PN-1 (protease nexin-1) are readily internalized in several cell types. Here we address the question whether uPAR is internalized as well upon binding of uPA-serpin complexes. Both LB6 clone 19 cells, a mouse cell line transfected with the human uPAR cDNA, and the human U937 monocytic cell line, express in addition to uPAR also the endocytic et2-macroglobulin receptor/low density lipoprotein receptor-related protein (LRP/a2-MR) which is required to internalize uPAR-bound uPA-PAI-1 and uPA-PN-1 complexes. Downregulation of cell surface uPAR molecules in U937 cells was detected by cytofluorimetric analysis after uPA-PAI-1 and uPA-PN-1 incubation for 30 min at 37°C; this effect was blocked by preincubation with the ligand of LRP/ aE-MR, RAP (LRP/a2-MR-associated protein), known to block the binding of the uPA complexes to LRP/et E-MR. Downregulation correlated in time with the intracellular appearance of uPAR as assessed by confocal microscopy and immuno-electron microscopy. After 30 min incubation with uPA-PAI-1 or uPA-PN-1 (but not with free uPA), confocal microscopy showed that uPAR staining in permeabilized LB6 clone 19 cells moved from a mostly surface associated to a largely perinuclear position. This effect was inhibited by the LRP/a2-MR RAP. Perinuclear uPAR did not represent newly synthesized nor a preexisting intracellular pool of uPAR, since this fluorescence pattern was not modified by treatment with the protein synthesis inhibitor cycloheximide, and since in LB6 clone 19 cells all of uPAR was expressed on the cell surface. Immuno-electron microscopy confirmed the plasma membrane to intracellular translocation of uPAR, and its dependence on LRP/ot2-MR in LB6 clone 19 cells only after binding to the uPA-PAI-1 complex. After 30 min incubation at 37°C with uPA-PAI-1, 93 % of the specific immunogold particles were present in cytoplasmic vacuoles vs 17.6% in the case of DFP-uPA. We conclude therefore that in the process of uPA-serpin internalization, uPAR itself is internalized, and that internalization requires the LRP/a2-MR.

show abstract

Regions involved in binding of urokinase-type-1 inhibitor complex and pro-urokinase to the endocytic alpha 2-macroglobulin receptor/low density lipoprotein receptor-related protein. Evidence that the urokinase receptor protects pro-urokinase against binding to the endocytic receptor.

Cited by 128 publications

References 42 publications

The tissue-type plasminogen activator–plasminogen activator inhibitor 1 complex promotes neurovascular injury in brain trauma: evidence from mice and humans

The tissue-type plasminogen activator–plasminogen activator inhibitor 1 complex promotes neurovascular injury in brain trauma: evidence from mice and humans

Intracellular Urokinase uPA-PAl-1 Complex: Disruption by Small Molecule Targets Hypoxically Programmed Glioma Cells

alpha-2 Macroglobulin receptor/Ldl receptor-related protein(Lrp)-dependent internalization of the urokinase receptor.

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