The Experts below are selected from a list of 2211 Experts worldwide ranked by ideXlab platform

Janko Kos - One of the best experts on this subject based on the ideXlab platform.

  • Neuroinflammation-Induced Upregulation of Glial Cathepsin X EXpression and Activity in vivo.
    Frontiers in molecular neuroscience, 2020
    Co-Authors: Anja Pišlar, Nace Zidar, Larisa Tratnjek, Gordana Glavan, Marko Živin, Janko Kos
    Abstract:

    Neuroinflammation is an important factor in the pathogenesis of neurodegenerative diseases. Microglia-derived lysosomal Cathepsins have been increasingly recognized as important inflammatory mediators that trigger signaling pathways that aggravate neuroinflammation. In vitro, a contribution to neuroinflammation processes has been shown for Cathepsin X: however, the eXpression patterns and functional role of Cathepsin X in neuroinflammatory brain pathology remain elusive. In this study we analyzed the eXpression, activity, regional distribution and cellular localization of Cathepsin X in the rat brain with neuroinflammation-induced neurodegeneration. The unilateral injection of lipopolysaccharide (LPS) induced a strong upregulation of Cathepsin X eXpression and its activity in the ipsilateral striatum. In addition to the striatum, Cathepsin X overeXpression was detected in other brain areas such as the cerebral corteX, corpus callosum, subventricular zone and eXternal globus pallidus, whereas the upregulation was mainly restricted to activated microglia and reactive astrocytes. Continuous administration of the Cathepsin X inhibitor AMS36 indicated protective effects against LPS-induced striatal degeneration, as seen by the attenuated LPS-mediated dilation of the lateral ventricles and partial decreased eXtent of striatal lesion. Taken together, our results indicate that Cathepsin X plays a role as a pathogenic factor in neuroinflammation-induced neurodegeneration and represents a potential therapeutic target for neurodegenerative diseases associated with neuroinflammation.

  • Structure-activity relationships of triazole-benzodioXine inhibitors of Cathepsin X.
    European journal of medicinal chemistry, 2020
    Co-Authors: Urša Pečar Fonović, Nace Zidar, Damijan Knez, Martina Hrast, Matic Proj, Stanislav Gobec, Janko Kos
    Abstract:

    Abstract Cathepsin X is a cysteine carboXypeptidase that is involved in various physiological and pathological processes. In particular, highly elevated eXpression and activity of Cathepsin X has been observed in cancers and neurodegenerative diseases. Previously, we identified compound Z9 (1-(2,3-dihydrobenzo[b][1,4]dioXin-6-yl)-2-((4-isopropyl-4H-1,2,4-triazol-3-yl)thio)ethan-1-one) as a potent and specific reversible Cathepsin X inhibitor. Here, we have eXplored the effects of chemical variations to Z9 of either benzodioXine or triazol moieties, and the importance of the central ketomethylenethio linker. The ketomethylenethio linker was crucial for Cathepsin X inhibition, whereas changes of the triazole heterocycle did not alter the inhibitory potencies to a greater eXtent. Replacement of benzodioXine moiety with substituted benzenes reduced Cathepsin X inhibition. Overall, several synthesized compounds showed similar or improved inhibitory potencies against Cathepsin X compared to Z9, with IC50 values of 7.1 μM–13.6 μM. Additionally, 25 inhibited prostate cancer cell migration by 21%, which is under the control of Cathepsin X.

  • The CarboXypeptidase Activity of Cathepsin X is Not Controlled by Endogenous Inhibitors
    Acta Chimica Slovenica, 2019
    Co-Authors: Urša Pečar Fonović, Nace Zidar, Milica Perišić Nanut, Brigita Lenarčič, Janko Kos
    Abstract:

    Cysteine Cathepsins are peptidases with housekeeping functions that play different specific roles in different tissues. Endogenous peptidase inhibitors, such as cystatins and thyropins are the ultimate way of controlling their activity. It appears, however, that Cathepsin X, a monocarboXypeptidase, whose overeXpression is associated with several pathological processes, is not under the control of endogenous inhibitors. Inhibitors belonging to various groups inhibit other Cathepsins tested, but none decrease the carboXypeptidase activity of Cathepsin X. This absence of inhibitor control is another feature that distinguishes Cathepsin X from other members of the cysteine peptidases.

  • Therapeutic potential of inhibition of the neuroinflammation induced Cathepsin X: in vivo evidence
    2019
    Co-Authors: Anja Pišlar, Nace Zidar, Larisa Tratnjek, Gordana Glavan, Marko Živin, Janko Kos
    Abstract:

    Abstract Parkinson’s disease (PD) is a progressive neurodegenerative disorder with unknown cause, but it has been postulated that chronic neuroinflammation may play a role in its pathogenesis. Microglia-derived lysosomal Cathepsins have been increasingly recognized as important inflammatory mediators. Here, we analyzed the regional distribution and cellular localization of the Cathepsin X in the rat brain with neuroinflammation-induced neurodegeneration. Unilateral injection of lipopolysaccharide (LPS) into the striatum induced strong upregulation of Cathepsin X eXpression and its activity in the ipsilateral striatum. In addition to the striatum, Cathepsin X overeXpression was detected in other areas such as cerebral corteX, corpus callosum, subventricular zone and eXternal globus pallidus mainly restricted to glial cells. Moreover, continuous administration of the Cathepsin X specific inhibitor AMS36 showed protective effects against LPS-induced striatal degeneration, as seen by the decreased eXtent of striatal lesion and decreased eXpression of neuroinflammation marker. These results demonstrate that glial upregulated Cathepsin X may play a role as a potential pathogenic factor in PD. Inhibition of Cathepsin X enzymatic activity thus may be useful in preventing neuroinflammation-induced neurodegeneration.

  • Upregulation of Cysteine Protease Cathepsin X in the 6-HydroXydopamine Model of Parkinson's Disease.
    Frontiers in molecular neuroscience, 2018
    Co-Authors: Anja Pišlar, Larisa Tratnjek, Gordana Glavan, Marko Živin, Janko Kos
    Abstract:

    Parkinson’s disease (PD) is a neurodegenerative disorder characterized by loss of midbrain dopaminergic neurons in the substantia nigra compacta (SNc). In vitro, a contribution to neuroinflammation and neurotoXicity has been shown for the lysosomal protease Cathepsin X; however, its eXpression and its role in PD remain unknown. Therefore, the current study was designed to address the regional, cellular and subcellular localization and activity of Cathepsin X in hemi-parkinsonian rats with 6-hydroXydopamine (6-OHDA)-induced eXcitotoXicity in the unilateral medial forebrain bundle (MFB) lesion. We report for the first time that Cathepsin X eXpression and activity are rapidly increased in the ipsilateral SNc after injection of 6-OHDA into the MFB reaching a maXimum after 12 h but seem to stay strongly upregulated after 4 weeks after injection. At early time points of 6-OHDA injection into the MFB, the increased Cathepsin X is localized in the lysosomes in the neuronal, predominantly tyrosine hydroXylase-positive dopaminergic cells. After 12 h of 6-OHDA induced lesion, only a few activated microglial cells are positive for Cathepsin X whereas, in 4 weeks post-lesion accompanied with complete loss of dopaminergic neurons, there is persistent Cathepsin X upregulation restricted to activated glia cells. Taken together, our results demonstrate that Cathepsin X upregulation in the lesioned dopaminergic system may play a role as a pathogenic factor in PD. Moreover, inhibition of Cathepsin X eXpression or activity may be useful in protecting the nigrostriatal dopaminergic projection in the PD.

Natasa Obermajer - One of the best experts on this subject based on the ideXlab platform.

  • Cysteine protease-mediated cytoskeleton interactions with LFA-1 promote T-cellmorphological changes
    Cell motility and the cytoskeleton, 2017
    Co-Authors: Janko Kos, Natasa Obermajer, Zala Jevnikar
    Abstract:

    T cells migrate through restrictive barriers in a protease-independent, amoeboid fashion that is characterized by morphological cell polarization. Theinteraction of cysteine-dependent carboXypeptidase Cathepsin X with 2 integrin LFA-1 (lymphocyte function associated antigen 1) induces T-cell morphological changes, displaying into a 3D eXtracellular matriX a cytoplasmicprojection termed a uropod. In the present study we show that inhibition of Cathepsin X and a cysteine-dependent endopeptidase, Cathepsin L,markedly inhibits T-cell actin polymerization, shape polarization, and chemotaXis. We propose that Cathepsin L promotes T-cell migration associated processes by activating proCathepsin X in the endolysosomal vesicles near the cell membrane and at the peak of the uropod, where both proteases were colocalized. We show that active Cathepsin X modifies the 2 cytoplasmic tail of LFA-1 in the uropod, promoting its high affinity conformation. We suggest that LFA-1 cleavage contributes to the conformational change in the cytoplasmic tail, promoting the binding of the cytoskeletal protein talin. This interaction is restricted to the uropod and results in the stabilization of this region, promoting LFA-1-mediated cell uropod elongation.

  • The role of Cathepsin X in the migration and invasiveness of T lymphocytes
    Journal of cell science, 2017
    Co-Authors: Janko Kos, Natasa Obermajer, Zala Jevnikar, Matthew Bogyo
    Abstract:

    Cathepsin X is a lysosomal cysteine protease eXhibiting carboXypeptidase activity. Its eXpression is high in the cells of immune system and its function has been related to the processes of inflammatory and immune responses. It regulates processes such as adhesion, T lymphocyte activation and phagocytosis through its interaction with [beta]2 integrins. To investigate therole of Cathepsin X in the migration of T lymphocytes, Jurkat T lymphocyteswere stably transfected with a pcDNA3 eXpression vector containing Cathepsin X cDNA. The Cathepsin-X-overeXpressing T lymphocytes eXhibited polarised migration-associated morphology, enhanced migration on 2D and 3D models using intercellular adhesion molecule 1 (ICAM1)- and Matrigel-coated surfaces, and increased homotypic aggregation. The increased invasiveness of Cathepsin-X-overeXpressing cells does not involve proteolytic degradation of eXtracellular matriX. Confocal microscopy showed that the active mature form of Cathepsin X was colocalised in migrating cells together with lymphocyte-function-associated antigen 1 (LFA-1). The colocalisation was particularly evident at the trailing edge protrusion, the uropod, that has an important role in T lymphocyte migration and cell-cell interactions. We propose that Cathepsin X causes cytoskeletal rearrangements and stimulates migration of T lymphocytes by modulating the activity of the [beta]2 integrin receptor LFA-1.

  • Cathepsin B, Cathepsin H, Cathepsin X and cystatin C in sera of patients with early-stage and inflammatory breast cancer
    The international journal of biological markers, 2017
    Co-Authors: Janko Kos, Natasa Obermajer, Robert Paridaens, Julie Decock, Wouter Hendrickx, Suzana Vozelj
    Abstract:

    Numerous studies have linked Cathepsins and their inhibitor cystatin C to tumor invasion and metastasis. We eXamined whether Cathepsin B, Cathepsin H, Cathepsin X and cystatin C could be detected in sera from women with earlystage or inflammatory breast cancer and whether they correlated with clinicopathological characteristics. Preoperative serum was obtained from 176 patients with early-stage breast cancer (tumor size ≤5 cm, negative lymph nodes) and 31 patients with inflammatory breast cancer. Cathepsin and cystatinC levels were measured by ELISA. The patient and tumor characteristics under study were age at diagnosis, menopausal status, tumor size, tumor grade, and steroid hormone receptor status. Serum Cathepsin B levels were significantly lower in patients with poorly differentiated tumors. High cystatin C levels were associated with tumor size, postmenopausal status and patient age. Interestingly, significantly lower levels of CathepsinX and H were found in patients with inflammatory breast cancer, a trend also observed for Cathepsin B and cystatin C. In conclusion, our resultsshow a limited association of Cathepsins B, H, X and cystatin C with established prognostic parameters. These data are promising and encourage future analysis of the clinical outcome of our patients in order to eXamine the potential prognostic value of these biomarkers. Further, this study indicates a role for Cathepsin X and H in inflammatory breast cancer.

  • Cathepsin X prevents an effective immune response against Helicobacter pylori infection
    European journal of cell biology, 2017
    Co-Authors: Janko Kos, Bojan Tepeš, Natasa Obermajer, Andreja Natasa Kopitar, Alojz Ihan, Špela Magister
    Abstract:

    Cathepsin X, a cysteine protease, has been shown to regulate an immune response by activating ?-2 integrin receptors. In this study we demonstrate its role in regulating the immune response to infection with H. pylori. The level of Cathepsin X was determined in THP-1 monocyte cells primed with H. pylori antigens isolated from subjects suffering from gastritis, who had either eradicated or not the disease after the antibiotic therapy. We show that the specific clinical outcome of H. pylori eradication therapy correlatesstrongly with the membrane eXpression of Cathepsin X in stimulated THP-1 cells, being significantly higher after stimulation with H. pylori strains from those subjects who did not respond to antibiotic therapy. The same antigens elicit a more vigorous immune response, increased eXpression of MHC II, however trigger inadequate cytokine profile (IFN-? and IL-4) to eradicate the pathogen. We propose that Cathepsin X mediated activation of ?-2integrin receptor Mac-1 suppresses the stimulatory signal in the form of cytokines. Cathepsin X co-localizes on the membrane of THP-1 cells with Mac-1 integrin receptor and its inhibition increases homotypic aggregation and mononuclear cell proliferation, events that are associated with low Mac-1 activity. Our study highlights the diversity of the innate immune response to H. pylori antigens leading to either successful eradication of the infection or maintenance of chronic inflammation, revealing Cathepsin X location and activity as a regulator of the effectiveness of H. pylori eradication.

  • Cathepsin X cleaves the C-terminal dipeptide of alpha- and gamma- enolase and impairs survival and neuritogenesis of neuronal cells
    International journal of biochemistry & cell biology, 2016
    Co-Authors: Janko Kos, Urša Pe?ar Fonovi?, Bojan Doljak, Polona Jamnik, Natasa Obermajer
    Abstract:

    The cysteine carboXypeptidase Cathepsin X has been recognized as an important player in degenerative processes during normal aging and in pathological conditions. In this study we identify isozymes alpha and gamma enolases as targets for Cathepsin X. Cathepsin X sequentially cleaves C-terminal amino acids of both isozymes, abolishing their neurotrophic activity. Neuronal cell survival and neuritogenesis are, in this way, regulated, as shown on pheochromocytoma cell line PC12. Inhibition of Cathepsin X activity increases generation of plasmin, essential for neuronal differentiation and changes the length distribution of neurites, especially in the early phase of neurite outgrowth. Moreover, Cathepsin X inhibition increases neuronal survival and reduces serum deprivation induced apoptosis, particularly in the absence of nerve growth factor. On the other hand, the proliferation of cells is decreased, indicating induction of differentiation. Our study reveals enolase isozymes as crucial neurotrophic factors that are regulated by the proteolyticactivity of Cathepsin X.

Zala Jevnikar - One of the best experts on this subject based on the ideXlab platform.

  • Cysteine protease-mediated cytoskeleton interactions with LFA-1 promote T-cellmorphological changes
    Cell motility and the cytoskeleton, 2017
    Co-Authors: Janko Kos, Natasa Obermajer, Zala Jevnikar
    Abstract:

    T cells migrate through restrictive barriers in a protease-independent, amoeboid fashion that is characterized by morphological cell polarization. Theinteraction of cysteine-dependent carboXypeptidase Cathepsin X with 2 integrin LFA-1 (lymphocyte function associated antigen 1) induces T-cell morphological changes, displaying into a 3D eXtracellular matriX a cytoplasmicprojection termed a uropod. In the present study we show that inhibition of Cathepsin X and a cysteine-dependent endopeptidase, Cathepsin L,markedly inhibits T-cell actin polymerization, shape polarization, and chemotaXis. We propose that Cathepsin L promotes T-cell migration associated processes by activating proCathepsin X in the endolysosomal vesicles near the cell membrane and at the peak of the uropod, where both proteases were colocalized. We show that active Cathepsin X modifies the 2 cytoplasmic tail of LFA-1 in the uropod, promoting its high affinity conformation. We suggest that LFA-1 cleavage contributes to the conformational change in the cytoplasmic tail, promoting the binding of the cytoskeletal protein talin. This interaction is restricted to the uropod and results in the stabilization of this region, promoting LFA-1-mediated cell uropod elongation.

  • The role of Cathepsin X in the migration and invasiveness of T lymphocytes
    Journal of cell science, 2017
    Co-Authors: Janko Kos, Natasa Obermajer, Zala Jevnikar, Matthew Bogyo
    Abstract:

    Cathepsin X is a lysosomal cysteine protease eXhibiting carboXypeptidase activity. Its eXpression is high in the cells of immune system and its function has been related to the processes of inflammatory and immune responses. It regulates processes such as adhesion, T lymphocyte activation and phagocytosis through its interaction with [beta]2 integrins. To investigate therole of Cathepsin X in the migration of T lymphocytes, Jurkat T lymphocyteswere stably transfected with a pcDNA3 eXpression vector containing Cathepsin X cDNA. The Cathepsin-X-overeXpressing T lymphocytes eXhibited polarised migration-associated morphology, enhanced migration on 2D and 3D models using intercellular adhesion molecule 1 (ICAM1)- and Matrigel-coated surfaces, and increased homotypic aggregation. The increased invasiveness of Cathepsin-X-overeXpressing cells does not involve proteolytic degradation of eXtracellular matriX. Confocal microscopy showed that the active mature form of Cathepsin X was colocalised in migrating cells together with lymphocyte-function-associated antigen 1 (LFA-1). The colocalisation was particularly evident at the trailing edge protrusion, the uropod, that has an important role in T lymphocyte migration and cell-cell interactions. We propose that Cathepsin X causes cytoskeletal rearrangements and stimulates migration of T lymphocytes by modulating the activity of the [beta]2 integrin receptor LFA-1.

  • Profilin 1 as a target for Cathepsin X activity in tumor cells
    PloS one, 2016
    Co-Authors: Janko Kos, Marko Fonovi?, Urša Pe?ar Fonovi?, Bojan Doljak, Zala Jevnikar, Polona Jamnik, Matija Rojnik
    Abstract:

    Cathepsin X has been reported to be a tumor promotion factor in various types of cancer; however, the molecular mechanisms linking its activity with malignant processes are not understood. Here we present profilin 1, a known tumor suppressor, as a target for Cathepsin X carboXypeptidase activity in prostate cancer PC-3 cells. Profilin 1 co-localizes strongly with Cathepsin X intracellularly in the perinuclear area as well as at the plasma membrane. Selective cleavage of C-terminal amino acids was demonstrated on a synthetic octapeptide representing the profilin C-terminal region, and on recombinant profilin 1. Further, intact profilin 1 binds its poly-L-proline ligand clathrin significantly better than it does the truncated one, as shown using Cathepsin X specific inhibitor AMS-36 and immunoprecipitation of the profilin 1/clathrin compleX. Moreover, the polymerization of actin, which depends also on the binding of poly-L-proline ligands to profilin 1, was promoted by AMS-36 treatment of cells and by siRNA Cathepsin X silencing. Our results demonstrate that increased adhesion, migration and invasiveness of tumor cells depend on the inactivation of the tumor suppressive function of profilin 1 by Cathepsin X. The latter is thus designated as a target for development of new antitumor strategies

  • Profilin 1 as a target for Cathepsin X activity in tumor cells. PLoS One 2013
    2016
    Co-Authors: Zala Jevnikar, Matija Rojnik, Bojan Doljak, Polona Jamnik, Marko Fonovic, Janko Kos
    Abstract:

    Cathepsin X has been reported to be a tumor promotion factor in various types of cancer; however, the molecular mechanisms linking its activity with malignant processes are not understood. Here we present profilin 1, a known tumor suppressor, as a target for Cathepsin X carboXypeptidase activity in prostate cancer PC-3 cells. Profilin 1 co-localizes strongly with Cathepsin X intracellularly in the perinuclear area as well as at the plasma membrane. Selective cleavage of C-terminal amino acids was demonstrated on a synthetic octapeptide representing the profilin C-terminal region, and on recombinant profilin 1. Further, intact profilin 1 binds its poly-L-proline ligand clathrin significantly better than it does the truncated one, as shown using Cathepsin X specific inhibitor AMS-36 and immunoprecipitation of the profilin 1/clathrin compleX. Moreover, the polymerization of actin, which depends also on the binding of poly-L-proline ligands to profilin 1, was promoted by AMS-36 treatment of cells and by siRNA Cathepsin X silencing. Our results demonstrate that increased adhesion, migration and invasiveness of tumor cells depend on the inactivation of the tumor suppressive function of profilin 1 by Cathepsin X. The latter is thus designated as a target for development of new antitumor strategies

  • lfa 1 fine tuning by Cathepsin X
    Iubmb Life, 2011
    Co-Authors: Zala Jevnikar, Natasa Obermajer, Janko Kos
    Abstract:

    The adhesion molecule lymphocyte function-associated antigen (LFA)-1 plays a key role in immune surveillance and response. Its conformation is spatially and temporally regulated, enabling adhesion and deadhesion during T-cell migration. LFA-1 adhesion to its major ligand intercellular adhesion molecule 1 is controlled by adaptor proteins which bind the cytoplasmic tail of the β (2) subunit. Cathepsin X, a cysteine carboXypeptidase, promotes T-cell migration and morphological changes by cleaving the β (2) cytoplasmic tail of LFA-1. In this way, it modulates the affinity of LFA-1 for structural adaptors talin-1 and α-actinin-1 and enables the stepwise transition between intermediate and high-affinity conformations of LFA-1, an event that is necessary for effective T-cell function. Cathepsin X regulation that would allow precise modulation of LFA-1 affinity has a great potential for anti-LFA-1 therapy.

Matthew Bogyo - One of the best experts on this subject based on the ideXlab platform.

  • The role of Cathepsin X in the migration and invasiveness of T lymphocytes
    Journal of cell science, 2017
    Co-Authors: Janko Kos, Natasa Obermajer, Zala Jevnikar, Matthew Bogyo
    Abstract:

    Cathepsin X is a lysosomal cysteine protease eXhibiting carboXypeptidase activity. Its eXpression is high in the cells of immune system and its function has been related to the processes of inflammatory and immune responses. It regulates processes such as adhesion, T lymphocyte activation and phagocytosis through its interaction with [beta]2 integrins. To investigate therole of Cathepsin X in the migration of T lymphocytes, Jurkat T lymphocyteswere stably transfected with a pcDNA3 eXpression vector containing Cathepsin X cDNA. The Cathepsin-X-overeXpressing T lymphocytes eXhibited polarised migration-associated morphology, enhanced migration on 2D and 3D models using intercellular adhesion molecule 1 (ICAM1)- and Matrigel-coated surfaces, and increased homotypic aggregation. The increased invasiveness of Cathepsin-X-overeXpressing cells does not involve proteolytic degradation of eXtracellular matriX. Confocal microscopy showed that the active mature form of Cathepsin X was colocalised in migrating cells together with lymphocyte-function-associated antigen 1 (LFA-1). The colocalisation was particularly evident at the trailing edge protrusion, the uropod, that has an important role in T lymphocyte migration and cell-cell interactions. We propose that Cathepsin X causes cytoskeletal rearrangements and stimulates migration of T lymphocytes by modulating the activity of the [beta]2 integrin receptor LFA-1.

  • Frontline Science: Multiple Cathepsins promote inflammasome-independent, particle-induced cell death during NLRP3-dependent IL-1β activation.
    Journal of leukocyte biology, 2017
    Co-Authors: Gregory M. Orlowski, Matthew Bogyo, Shruti Sharma, Jeff D. Colbert, Stephanie A. Robertson, Hiroshi Kataoka, Francis Ka-ming Chan, Kenneth L. Rock
    Abstract:

    Sterile particles cause several chronic, inflammatory diseases, characterized by repeating cycles of particle phagocytosis and inflammatory cell death. Recent studies have proposed that these processes are driven by the NLRP3 inflammasome, a platform activated by phagocytosed particles, which controls both caspase-1-dependent cell death (pyroptosis) and mature IL-1β secretion. After phagocytosis, particles can disrupt lysosomes, and inhibitor studies have suggested that the resulting release of a lysosomal protease-Cathepsin B-into the cytosol somehow activates NLRP3. However, using primary murine macrophages, we found that particle-induced cell death occurs independent of NLRP3/caspase-1 and depends instead on multiple, redundant Cathepsins. In contrast, nigericin, a soluble activator of NLRP3 inflammasomes, induced cell death that was dependent on the NLRP3. Interestingly, nigericin-induced cell death depended partly on a single Cathepsin, Cathepsin X. By inhibiting or silencing multiple Cathepsins in macrophages, several key proinflammatory events induced by sterile particles are blocked, including cell death, pro-IL-1β production, and IL-1β secretion. These data suggest that Cathepsins might be potential therapeutic targets in particulate-mediated inflammatory disease. In support of this concept, we find that a broad-spectrum Cathepsin inhibitor can suppress particle-induced IL-1-dependent peritonitis.

  • Maturation of dendritic cells depends on proteolytic cleavage by Cathepsin X
    Journal of leukocyte biology, 2016
    Co-Authors: Matjaž Jeras, Natasa Obermajer, Janko Kos, Urban Svajger, Matthew Bogyo
    Abstract:

    The maturation status of dendritic cells (DCs) is crucial for effective antigen presentation and initiation of the primary immune response. Maturationstimuli cause the adhesion of immature DCs to the eXtracellular matriX, which is accompanied by recruitment of the CD11bžCD18 šmacrophage antigen-1 (Mac-1)đ integrin receptor, cytoskeleton reorganization, and podosome formation. Cathepsin X, a cysteine protease eXpressed in DCs and other APCs, is involved in Mac-1 activation. We have shown that during maturation, Cathepsin X translocates to the plasma membrane of maturing DCs, enabling Mac-1 activation and consequently, cell adhesion. In mature DCs, Cathepsin X redistributes from the membrane to the perinuclear region, which coincides with the de-adhesion of DCs, formation of cell clusters, and acquisition of the mature phenotype. Inhibition of Cathepsin X activity duringDC differentiation and maturation resulted in an altered phenotype and function of mature DCs. It reduced surface eXpression of costimulatory molecules, increased eXpression of inhibitory Ig-like transcripts 3 and 4 (ILT3 and ILT4), almost completely abolished cytokine production, diminished migration, and reduced the capacity of DCs to stimulate T lymphocytes. These results stress the importance of Cathepsin X in regulating DC adhesion, a crucial event for their maturation and T cell activation.

  • Multiple Cathepsins Promote Pro–IL-1β Synthesis and NLRP3-Mediated IL-1β Activation
    Journal of immunology (Baltimore Md. : 1950), 2015
    Co-Authors: Gregory M. Orlowski, Matthew Bogyo, Shruti Sharma, Jeff D. Colbert, Stephanie A. Robertson, Kenneth L. Rock
    Abstract:

    Sterile particles induce robust inflammatory responses that underlie the pathogenesis of diseases like silicosis, gout, and atherosclerosis. A key cytokine mediating this response is IL-1β. The generation of bioactive IL-1β by sterile particles is mediated by the NOD-like receptor containing a pyrin domain 3 (NLRP3) inflammasome, although eXactly how this occurs is incompletely resolved. Prior studies have found that the Cathepsin B inhibitor, Ca074Me, suppresses this response, supporting a model whereby ingested particles disrupt lysosomes and release Cathepsin B into the cytosol, somehow activating NLRP3. However, reports that Cathepsin B-deficient macrophages have no defect in particle-induced IL-1β generation have questioned Cathepsin B’s involvement. In this study, we eXamine the hypothesis that multiple redundant Cathepsins (not just Cathepsin B) mediate this process by evaluating IL-1β generation in murine macrophages, singly or multiply deficient in Cathepsins B, L, C, S and X. Using an activity-based probe, we measure specific Cathepsin activity in living cells, documenting compensatory changes in Cathepsin-deficient cells, and Ca074Me’s dose-dependent Cathepsin inhibition profile is analyzed in parallel with its suppression of particle-induced IL-1β secretion. Also, we evaluate endogenous Cathepsin inhibitors cystatins C and B. Surprisingly, we find that multiple redundant Cathepsins, inhibited by Ca074Me and cystatins, promote pro–IL-1β synthesis, and to our knowledge, we provide the first evidence that Cathepsin X plays a nonredundant role in nonparticulate NLRP3 activation. Finally, we find Cathepsin inhibitors selectively block particle-induced NLRP3 activation, independently of suppressing pro–IL-1β synthesis. Altogether, we demonstrate that both small molecule and endogenous Cathepsin inhibitors suppress particle-induced IL-1β secretion, implicating roles for multiple Cathepsins in both pro–IL-1β synthesis and NLRP3 activation.

  • Development of activity-based probes for Cathepsin X
    ACS chemical biology, 2011
    Co-Authors: Margot G. Paulick, Matthew Bogyo
    Abstract:

    Cathepsin X is a lysosomal cysteine protease that functions as a carboXypeptidase with broad substrate specificity. Cathepsin X was discovered only recently, and its physiological roles are still not well understood. A number of studies suggest that Cathepsin X may be involved in a variety of biological processes, including cancer, aging and degenerative conditions of the brain, inflammation, and cellular communication. Here we present the synthesis and characterization of several activity-based probes (ABPs) that target active Cathepsin X. These ABPs were used to label Cathepsin X in compleX lysates, whole cells, and in vivo. Furthermore, we have developed a method for selectively labeling and visualizing active Cathepsin X in vitro and in vivo. Overall, the probes developed in this study are valuable tools for the study of Cathepsin X function.

Bojan Doljak - One of the best experts on this subject based on the ideXlab platform.

  • Identification and characterization of the novel reversible and selective Cathepsin X inhibitors
    Nature Publishing Group, 2017
    Co-Authors: Urša Pečar Fonović, Anja Pišlar, Bojan Doljak, Damijan Knez, Ana Mitrović, Tanja Jakoš, Boris Brus, Jure Stojan, Simon Žakelj, Jurij Trontelj
    Abstract:

    Abstract Cathepsin X is a cysteine peptidase involved in the progression of cancer and neurodegenerative diseases. Targeting this enzyme with selective inhibitors opens a new possibility for intervention in several therapeutic areas. In this study triazole-based reversible and selective inhibitors of Cathepsin X have been identified. Their selectivity and binding is enhanced when the 2,3-dihydrobenzo[b][1,4]dioXine moiety is present as the R1 substituent. Of a series of selected triazole-benzodioXine derivatives, compound 22 is the most potent inhibitor of Cathepsin X carboXypeptidase activity (Ki = 2.45 ± 0.05 μM) with at least 100-fold greater selectivity in comparison to Cathepsin B or other related cysteine peptidases. Compound 22 is not cytotoXic to prostate cancer cells PC-3 or pheochromocytoma PC-12 cells at concentrations up to 10 μM. It significantly inhibits the migration of tumor cells and increases the outgrowth of neurites, both processes being under the control of Cathepsin X carboXypeptidase activity. Compound 22 and other characterized triazole-based inhibitors thus possess a great potential for further development resulting in several in vivo applications

  • Cathepsin X cleaves the C-terminal dipeptide of alpha- and gamma- enolase and impairs survival and neuritogenesis of neuronal cells
    International journal of biochemistry & cell biology, 2016
    Co-Authors: Janko Kos, Urša Pe?ar Fonovi?, Bojan Doljak, Polona Jamnik, Natasa Obermajer
    Abstract:

    The cysteine carboXypeptidase Cathepsin X has been recognized as an important player in degenerative processes during normal aging and in pathological conditions. In this study we identify isozymes alpha and gamma enolases as targets for Cathepsin X. Cathepsin X sequentially cleaves C-terminal amino acids of both isozymes, abolishing their neurotrophic activity. Neuronal cell survival and neuritogenesis are, in this way, regulated, as shown on pheochromocytoma cell line PC12. Inhibition of Cathepsin X activity increases generation of plasmin, essential for neuronal differentiation and changes the length distribution of neurites, especially in the early phase of neurite outgrowth. Moreover, Cathepsin X inhibition increases neuronal survival and reduces serum deprivation induced apoptosis, particularly in the absence of nerve growth factor. On the other hand, the proliferation of cells is decreased, indicating induction of differentiation. Our study reveals enolase isozymes as crucial neurotrophic factors that are regulated by the proteolyticactivity of Cathepsin X.

  • Profilin 1 as a target for Cathepsin X activity in tumor cells
    PloS one, 2016
    Co-Authors: Janko Kos, Marko Fonovi?, Urša Pe?ar Fonovi?, Bojan Doljak, Zala Jevnikar, Polona Jamnik, Matija Rojnik
    Abstract:

    Cathepsin X has been reported to be a tumor promotion factor in various types of cancer; however, the molecular mechanisms linking its activity with malignant processes are not understood. Here we present profilin 1, a known tumor suppressor, as a target for Cathepsin X carboXypeptidase activity in prostate cancer PC-3 cells. Profilin 1 co-localizes strongly with Cathepsin X intracellularly in the perinuclear area as well as at the plasma membrane. Selective cleavage of C-terminal amino acids was demonstrated on a synthetic octapeptide representing the profilin C-terminal region, and on recombinant profilin 1. Further, intact profilin 1 binds its poly-L-proline ligand clathrin significantly better than it does the truncated one, as shown using Cathepsin X specific inhibitor AMS-36 and immunoprecipitation of the profilin 1/clathrin compleX. Moreover, the polymerization of actin, which depends also on the binding of poly-L-proline ligands to profilin 1, was promoted by AMS-36 treatment of cells and by siRNA Cathepsin X silencing. Our results demonstrate that increased adhesion, migration and invasiveness of tumor cells depend on the inactivation of the tumor suppressive function of profilin 1 by Cathepsin X. The latter is thus designated as a target for development of new antitumor strategies

  • Profilin 1 as a target for Cathepsin X activity in tumor cells. PLoS One 2013
    2016
    Co-Authors: Zala Jevnikar, Matija Rojnik, Bojan Doljak, Polona Jamnik, Marko Fonovic, Janko Kos
    Abstract:

    Cathepsin X has been reported to be a tumor promotion factor in various types of cancer; however, the molecular mechanisms linking its activity with malignant processes are not understood. Here we present profilin 1, a known tumor suppressor, as a target for Cathepsin X carboXypeptidase activity in prostate cancer PC-3 cells. Profilin 1 co-localizes strongly with Cathepsin X intracellularly in the perinuclear area as well as at the plasma membrane. Selective cleavage of C-terminal amino acids was demonstrated on a synthetic octapeptide representing the profilin C-terminal region, and on recombinant profilin 1. Further, intact profilin 1 binds its poly-L-proline ligand clathrin significantly better than it does the truncated one, as shown using Cathepsin X specific inhibitor AMS-36 and immunoprecipitation of the profilin 1/clathrin compleX. Moreover, the polymerization of actin, which depends also on the binding of poly-L-proline ligands to profilin 1, was promoted by AMS-36 treatment of cells and by siRNA Cathepsin X silencing. Our results demonstrate that increased adhesion, migration and invasiveness of tumor cells depend on the inactivation of the tumor suppressive function of profilin 1 by Cathepsin X. The latter is thus designated as a target for development of new antitumor strategies

  • Cathepsin X cleavage of the β2 integrin regulates talin binding and lfa 1 affinity in t cells
    Journal of Leukocyte Biology, 2011
    Co-Authors: Zala Jevnikar, Natasa Obermajer, Bojan Doljak, Urban Svajger, Stanislav Gobec, Samo Turk, Stephan Hailfinger, Margot Thome, Janko Kos
    Abstract:

    T cell migration, essential for immune surveillance and response, is mediated by the integrin LFA-1. CatX, a cysteine carboXypeptidase, is involved in the regulation of T cell migration by interaction with LFA-1. We show that sequential cleavage of C-terminal amino acids from the β(2) cytoplasmic tail of LFA-1, by CatX, enhances binding of the adaptor protein talin to LFA-1 and triggers formation of the latter's high-affinity form. As shown by SPR analysis of peptides constituting the truncated β(2) tail, the cleavage of three C-terminal amino acids by CatX resulted in a 1.6-fold increase of talin binding. Removal of one more amino acid resulted in a 2.5-fold increase over the intact tail. CatX cleavage increased talin-binding affinity to the MD but not the MP talin-binding site on the β(2) tail. This was shown by molecular modeling of the β(2) tail/talin F3 compleX to be a result of conformational changes affecting primarily the distal-binding site. Analysis of LFA-1 by conformation-specific mAb showed that CatX modulates LFA-1 affinity, promoting formation of high-affinity from intermediate-affinity LFA-1 but not the initial activation of LFA-1 from a bent to eXtended form. CatX post-translational modifications may thus represent a mechanism of LFA-1 fine-tuning that enables the trafficking of T cells.