The Experts below are selected from a list of 1026 Experts worldwide ranked by ideXlab platform
Judith S Bond - One of the best experts on this subject based on the ideXlab platform.
-
microbial induced Meprin β cleavage in muc2 mucin and a functional cftr channel are required to release anchored small intestinal mucus
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Andre Schutte, Judith S Bond, Daniel Lottaz, Christoph Beckerpauly, Stefan Muller, Anna Ermund, Malin E V Johansson, Ana M Rodriguezpineiro, Fredrik Backhed, Gunnar C HanssonAbstract:The mucus that covers and protects the epithelium of the intestine is built around its major structural component, the gel-forming MUC2 mucin. The gel-forming mucins have traditionally been assumed to be secreted as nonattached. The colon has a two-layered mucus system where the inner mucus is attached to the epithelium, whereas the small intestine normally has a nonattached mucus. However, the mucus of the small intestine of Meprin β-deficient mice was now found to be attached. Meprin β is an endogenous zinc-dependent metalloprotease now shown to cleave the N-terminal region of the MUC2 mucin at two specific sites. When recombinant Meprin β was added to the attached mucus of Meprin β-deficient mice, the mucus was detached from the epithelium. Similar to Meprin β-deficient mice, germ-free mice have attached mucus as they did not shed the membrane-anchored Meprin β into the luminal mucus. The ileal mucus of cystic fibrosis (CF) mice with a nonfunctional cystic fibrosis transmembrane conductance regulator (CFTR) channel was recently shown to be attached to the epithelium. Addition of recombinant Meprin β to CF mucus did not release the mucus, but further addition of bicarbonate rendered the CF mucus normal, suggesting that MUC2 unfolding exposed the Meprin β cleavage sites. Mucus is thus secreted attached to the goblet cells and requires an enzyme, Meprin β in the small intestine, to be detached and released into the intestinal lumen. This process regulates mucus properties, can be triggered by bacterial contact, and is nonfunctional in CF due to poor mucin unfolding.
-
Meprin metalloproteases inactivate interleukin 6
Journal of Biological Chemistry, 2014Co-Authors: Timothy R Keiffer, Judith S BondAbstract:Meprins have been implicated in the pathogenesis of several inflammatory diseases, including inflammatory bowel disease, in which the cytokine IL-6 is a prominent effector molecule. Because IL-6 levels are elevated markedly in Meprin α and α/β knockout mice in an experimental model of inflammatory bowel disease, the interaction between Meprins and IL-6 was studied. The results demonstrate that rodent and human Meprin A and B cleave IL-6 to a smaller product and, subsequently, are capable of extensive degradation of the cytokine. Analysis of the limited degradation product formed by Meprin A indicated that three to five amino acids are removed from the C terminus of the cytokine. Meprin A and Meprin B cleaved IL-6 with micromolar affinities (Km of 4.7 and 12.0 μm, respectively) and with high efficiencies (kcat/Km of 0.2 and 2.5 (m−1/s−1) × 106, respectively). These efficiency constants are among the highest for known Meprin substrates. Madin-Darby canine kidney cells transiently transfected with Meprin α or Meprin β constructs also cleave exogenous IL-6. Both human and murine IL-6 cleaved by Meprin A or B are inactivated, as demonstrated by their decreased capability to stimulate proliferation of B9 cells. These results are consistent with the proposition that one function of Meprin metalloproteases is to modulate inflammation by inactivating IL-6.
-
Meprin a impairs epithelial barrier function enhances monocyte migration and cleaves the tight junction protein occludin
American Journal of Physiology-renal Physiology, 2013Co-Authors: Jialing Bao, Gail L Matters, Renee Yura, Gaylen S Bradley, Pan Shi, Fang Tian, Judith S BondAbstract:Meprin metalloproteases are highly expressed at the luminal interface of the intestine and kidney and in certain leukocytes. Meprins cleave a variety of substrates in vitro, including extracellular matrix proteins, adherens junction proteins, and cytokines, and have been implicated in a number of inflammatory diseases. The linkage between results in vitro and pathogenesis, however, has not been elucidated. The present study aimed to determine whether Meprins are determinative factors in disrupting the barrier function of the epithelium. Active Meprin A or Meprin B applied to Madin-Darby canine kidney (MDCK) cell monolayers increased permeability to fluorescein isothiocyanate-dextran and disrupted immunostaining of the tight junction protein occludin but not claudin-4. Meprin A, but not Meprin B, cleaved occludin in MDCK monolayers. Experiments with recombinant occludin demonstrated that Meprin A cleaves the protein between Gly100 and Ser101 on the first extracellular loop. In vivo experiments demonstrated that Meprin A infused into the mouse bladder increased the epithelium permeability to sodium fluorescein. Furthermore, monocytes from Meprin knockout mice on a C57BL/6 background were less able to migrate through an MDCK monolayer than monocytes from their wild-type counterparts. These results demonstrate the capability of Meprin A to disrupt epithelial barriers and implicate occludin as one of the important targets of Meprin A that may modulate inflammation.
-
Post-transcriptional Regulation of Meprin α by the RNA-binding Proteins Hu Antigen R (HuR) and Tristetraprolin (TTP)
The Journal of biological chemistry, 2012Co-Authors: Alanna Roff, Judith S Bond, Ronaldo P. Panganiban, Faoud T. IshmaelAbstract:Meprins are multimeric proteases that are implicated in inflammatory bowel disease by both genetic association studies and functional studies in knock-out mice. Patients with inflammatory bowel disease show decreased colonic expression of Meprin α, although regulation of expression, particularly under inflammatory stimuli, has not been studied. The studies herein demonstrate that the human Meprin α transcript is bound and stabilized by Hu antigen R at baseline, and that treatment with the inflammatory stimulus phorbol 12-myristate 13-acetate downregulates Meprin α expression by inducing tristetraprolin. The enhanced binding of tristetraprolin to the MEP1A 3′-UTR results in destabilization of the transcript and occurs at a discrete site from Hu antigen R. This is the first report to describe a mechanism for post-transcriptional regulation of Meprin α and will help clarify the role of Meprins in the inflammatory response and disease.
-
activation of the epithelial sodium channel by the metalloprotease Meprin β subunit
Channels, 2011Co-Authors: Agustin Garciacaballero, Judith S Bond, Susan S. Ishmael, Yan Dang, Daniel Gillie, Sharon L Milgram, Jackson M StuttsAbstract:The Epithelial Na+ Channel (ENaC) is an apical heteromeric channel that mediates Na+ entry into epithelial cells from the luminal cell surface. ENaC is activated by proteases that interact with the channel during biosynthesis or at the extracellular surface. Meprins are cell surface and secreted metalloproteinases of the kidney and intestine. We discovered by affinity chromatography that Meprins bind γ-ENaC, a subunit of the ENaC hetero-oligomer. The physical interaction involves NH2-terminal cytoplasmic residues 37-54 of γ-ENaC, containing a critical gating domain immediately before the first transmembrane domain, and the cytoplasmic COOH-terminal tail of Meprin β (residues 679-704). This potential association was confirmed by co-expression and co-immunoprecipitation studies. Functional assays revealed that Meprins stimulate ENaC expressed exogenously in Xenopus oocytes and endogenously in epithelial cells. Co-expression of ENaC subunits and Meprin β or α/β in Xenopus oocytes increased amiloride-sensitiv...
Christoph Beckerpauly - One of the best experts on this subject based on the ideXlab platform.
-
Meprin and adam proteases as triggers of systemic inflammation in sepsis
FEBS Letters, 2021Co-Authors: Sascha Rahn, Christoph BeckerpaulyAbstract:Systemic inflammatory disorders (SIDs) comprise a broad range of diseases characterized by dysregulated excessive innate immune responses. Severe forms of SIDs can lead to organ failure and death, and their increasing incidence represents a major issue for the health care system. Protease-mediated ectodomain shedding of cytokines and their receptors represents a central mechanism in the regulation of inflammatory responses. The metalloprotease A Disintegrin And Metalloproteinase (ADAM) 17 is the best-characterized ectodomain sheddase capable of releasing TNF-α and soluble IL-6 receptor, which are decisive factors of systemic inflammation. Recently, Meprin metalloproteases were also identified as IL-6 receptor sheddases and activators of the pro-inflammatory cytokines IL-1β and IL-18. In different mouse models of SID, particularly those mimicking a sepsis-like phenotype, ADAM17 and Meprins have been found to promote disease progression. In this review, we summarize the role of ADAM10, ADAM17 and Meprins in the onset and progression of sepsis and discuss their potential as therapeutic targets.
-
phosphorylation of Meprin β controls its cell surface abundance and subsequently diminishes ectodomain shedding
The FASEB Journal, 2021Co-Authors: Fred Armbrust, Claus U Pietrzik, Tomas Koudelka, Andreas Tholey, Kira Bickenbach, Christoph BeckerpaulyAbstract:Meprin β is a zinc-dependent metalloprotease exhibiting a unique cleavage specificity with strong preference for acidic amino acids at the cleavage site. Proteomic studies revealed a diverse substrate pool of Meprin β including the interleukin-6 receptor (IL-6R) and the amyloid precursor protein (APP). Dysregulation of Meprin β is often associated with pathological conditions such as chronic inflammation, fibrosis, or Alzheimer's disease (AD). The extracellular regulation of Meprin β including interactors, sheddases, and activators has been intensively investigated while intracellular regulation has been barely addressed in the literature. This study aimed to analyze C-terminal phosphorylation of Meprin β with regard to cell surface expression and proteolytic activity. By immunoprecipitation of endogenous Meprin β from the colon cancer cell line Colo320 and subsequent LC-MS analysis, we identified several phosphorylation sites in its C-terminal region. Here, T694 in the C-terminus of Meprin β was the most preferred residue after phorbol 12-myristate 13-acetate (PMA) stimulation. We further demonstrated the role of protein kinase C (PKC) isoforms for Meprin β phosphorylation and identified the involvement of PKC-α and PKC-β. As a result of phosphorylation, the Meprin β activity at the cell surface is reduced and, consequently, the extent of substrate cleavage is diminished. Our data indicate that this decrease of the surface activity is caused by the internalization and degradation of Meprin β.
-
distinct contributions of Meprins to skin regeneration after injury Meprin α a physiological processer of pro collagen vii
Matrix biology plus, 2021Co-Authors: Daniel Kruppa, Christoph Beckerpauly, Florian Peters, Olivier Bornert, Mareike D Maler, Stefan F Martin, Alexander NystromAbstract:Abstract Astacin-like proteinases (ALPs) are regulators of tissue and extracellular matrix (ECM) homeostasis. They convey this property through their ability to convert ECM protein pro-forms to functional mature proteins and by regulating the bioavailability of growth factors that stimulate ECM synthesis. The most studied ALPs in this context are the BMP-1/tolloid-like proteinases. The other subclass of ALPs in vertebrates – the Meprins, comprised of Meprin α and Meprin β – are emerging as regulators of tissue and ECM homeostasis but have so far been only limitedly investigated. Here, we functionally assessed the roles of Meprins in skin wound healing using mice genetically deficient in one or both Meprins. Meprin deficiency did not change the course of macroscopic wound closure. However, subtle but distinct contributions of Meprins to the healing process and dermal homeostasis were observed. Loss of both Meprins delayed re-epithelialization and reduced macrophage infiltration. Abnormal dermal healing and ECM regeneration was observed in Meprin deficient wounds. Our analyses also revealed Meprin α as one proteinase responsible for maturation of pro-collagen VII to anchoring fibril-forming-competent collagen VII in vivo. Collectively, our study identifies Meprins as subtle players in skin wound healing.
-
discovery and optimization of selective inhibitors of Meprin α part i
Pharmaceuticals policy and law, 2021Co-Authors: Shurong Hou, Christoph Beckerpauly, Juan Diez, Chao Wang, Gregg B Fields, Thomas D Bannister, Timothy P Spicer, Louis Scampavia, Dmitriy MinondAbstract:Meprin α and β are zinc-dependent proteinases implicated in multiple diseases including cancers, fibrosis, and Alzheimer's. However, until recently, only a few inhibitors of either Meprin were reported and no inhibitors are in preclinical development. Moreover, inhibitors of other metzincins developed in previous years are not effective in inhibiting Meprins suggesting the need for de novo discovery effort. To address the paucity of tractable Meprin inhibitors we developed ultrahigh-throughput assays and conducted parallel screening of >650,000 compounds against each Meprin. As a result of this effort, we identified five selective Meprin α hits belonging to three different chemotypes (triazole-hydroxyacetamides, sulfonamide-hydroxypropanamides, and phenoxy-hydroxyacetamides). These hits demonstrated a nanomolar to micromolar inhibitory activity against Meprin α with low cytotoxicity and >30-fold selectivity against Meprin β and other related metzincincs. These selective inhibitors of Meprin α provide a good starting point for further optimization.
-
the cancer associated Meprin β variant g32r provides an additional activation site and promotes cancer cell invasion
Journal of Cell Science, 2019Co-Authors: Henning Schaffler, Christoph Beckerpauly, Florian Peters, Ole Helm, Sandra Kruger, Christine Boger, Christoph Rocken, Susanne Sebens, Ralph Lucius, Philipp ArnoldAbstract:The extracellular metalloprotease Meprin β is expressed as a homodimer and is primarily membrane bound. Meprin β can be released from the cell surface by its known sheddases ADAM10 and ADAM17. Activation of pro-Meprin β at the cell surface prevents its shedding, thereby stabilizing its proteolytic activity at the plasma membrane. We show that a single amino acid exchange variant (p.G32R) of Meprin β, identified in endometrium cancer, is more active against a peptide substrate and the IL-6 receptor than wild type Meprin β. We demonstrate that the inserted arginine at position 32 represents an additional activation site used by furin-like proteases in the Golgi, which consequently leads to reduced shedding by ADAM17. We investigated this Meprin β p.G32R variant to assess cell proliferation, invasion through a collagen IV matrix and outgrowth from tumor spheroids. We found that increased Meprin β p.G32R activity at the cell surface reduces cell proliferation, but increases cell invasion.
Erwin E Sterchi - One of the best experts on this subject based on the ideXlab platform.
-
a novel 2d based approach to the discovery of candidate substrates for the metalloendopeptidase Meprin
FEBS Journal, 2008Co-Authors: Daniel Ambort, Daniel Stalder, Daniel Lottaz, Maya Huguenin, Beatrice Oneda, Manfred Heller, Erwin E SterchiAbstract:In the past, protease-substrate finding proved to be rather haphazard and was executed by in vitro cleavage assays using singly selected targets. In the present study, we report the first protease proteomic approach applied to Meprin, an astacin-like metalloendopeptidase, to determine physiological substrates in a cell-based system of Madin-Darby canine kidney epithelial cells. A simple 2D IEF/SDS/PAGE-based image analysis procedure was designed to find candidate substrates in conditioned media of Madin-Darby canine kidney cells expressing Meprin in zymogen or in active form. The method enabled the discovery of hitherto unknown Meprin substrates with shortened (non-trypsin-generated) N- and C-terminally truncated cleavage products in peptide fragments upon LC-MS/MS analysis. Of 22 (17 nonredundant) candidate substrates identified, the proteolytic processing of vinculin, lysyl oxidase, collagen type V and annexin A1 was analysed by means of immunoblotting validation experiments. The classification of substrates into functional groups may propose new functions for Meprins in the regulation of cell homeostasis and the extracellular environment, and in innate immunity, respectively.
-
Metalloprotease Meprinb in Rat Kidney: Glomerular Localization and Differential Expression in
2013-03-29, 2008Co-Authors: Beatrice Oneda, Daniel Ambort, Daniel Lottaz, Maya Huguenin, Walter Stocker, Christoph Becker-pauly, Nadège Lods, Hans-peter Marti, Erwin E SterchiAbstract:Meprin (EC 3.4.24.18) is an oligomeric metalloendopeptidase found in microvillar membranes of kidney proximal tubular epithelial cells. Here, we present the first report on the expression of Meprinb in rat glomerular epithelial cells and suggest a potential involvement in experimental glomerular disease. We detected Meprinb in glomeruli of immunostained rat kidney sections on the protein level and by quantitative RT-PCR of laser-capture microdissected glomeruli on the mRNA level. Using immuno-gold staining we identified the membrane of podocyte foot processes as the main site of Meprinb expression. The glomerular Meprinb expression pattern was altered in anti-Thy 1.1 and passive Heymann nephritis (PHN). In addition, the Meprinb staining pattern in the latter was reminiscent of immunostaining with the sheep anti-Fx1A antiserum, commonly used in PHN induction. Using Western blot and immunoprecipitation assays we demonstrated that Meprinb is recognized by Fx1A antiserum and may therefore represent an auto-antigen in PHN. In anti-Thy 1.1 glomerulonephritis we observed a striking redistribution of Meprinb in tubular epithelial cells from the apical to the basolateral side and the cytosol. This might
-
the α and β subunits of the metalloprotease Meprin are expressed in separate layers of human epidermis revealing different functions in keratinocyte proliferation and differentiation
Journal of Investigative Dermatology, 2007Co-Authors: Christoph Beckerpauly, Daniel Lottaz, Erwin E Sterchi, M Debela, Markus Howel, Tatjana Walker, Annica Vlad, Karin Aufenvenne, Vinzenz Oji, Viktor MagdolenAbstract:The zinc endopeptidase Meprin (EC 3.4.24.18) is expressed in brush border membranes of intestine and kidney tubules, intestinal leukocytes, and certain cancer cells, suggesting a role in epithelial differentiation and cell migration. Here we show by RT-PCR and immunoblotting that Meprin is also expressed in human skin. As visualized by immunohistochemistry, the two Meprin subunits are localized in separate cell layers of the human epidermis. Meprin α is expressed in the stratum basale, whereas Meprin β is found in cells of the stratum granulosum just beneath the stratum corneum. In hyperproliferative epidermis such as in psoriasis vulgaris, Meprin α showed a marked shift of expression from the basal to the uppermost layers of the epidermis. The expression patterns suggest distinct functions for the two subunits in skin. This assumption is supported by diverse effects of recombinant Meprin α and β on human adult low-calcium high-temperature keratinocytes. Here, β induced a dramatic change in cell morphology and reduced the cell number, indicating a function in terminal differentiation, whereas Meprin α did not affect cell viability, and may play a role in basal keratinocyte proliferation.
-
human Meprin alpha and beta homo oligomers cleavage of basement membrane proteins and sensitivity to metalloprotease inhibitors
Biochemical Journal, 2004Co-Authors: Markusn Kruse, Daniel Lottaz, Erwin E Sterchi, Hanswilli Krell, Christoph R Becker, Danny Kohler, Irene Yiallouros, Walter StockerAbstract:: Meprin is a zinc endopeptidase of the astacin family, which is expressed as a membrane-bound or secreted protein in mammalian epithelial cells, in intestinal leucocytes and in certain cancer cells. There are two types of Meprin subunits, alpha and beta, which form disulphide-bonded homo- and hetero-oligomers. Here we report on the cleavage of matrix proteins by hMeprin (human Meprin) alpha and beta homo-oligomers, and on the interactions of these enzymes with inhibitors. Despite their completely different cleavage specificities, both hMeprin alpha and beta are able to hydrolyse basement membrane components such as collagen IV, nidogen-1 and fibronectin. However, they are inactive against intact collagen I. Hence the matrix-cleaving activity of hMeprin resembles that of gelatinases rather than collagenases. HMeprin is inhibited by hydroxamic acid derivatives such as batimastat, galardin and Pro-Leu-Gly-hydroxamate, by TAPI-0 (tumour necrosis factor alpha protease inhibitor-0) and TAPI-2, and by thiol-based compounds such as captopril. Therapeutic targets for these inhibitors are MMPs (matrix metalloproteases), TACE (tumour necrosis factor alpha-converting enzyme) and angiotensin-converting enzyme respectively. The most effective inhibitor of hMeprin alpha in the present study was the naturally occurring hydroxamate actinonin ( K(i)=20 nM). The marked variance in the cleavage specificities of hMeprin alpha and beta is reflected by their interaction with the TACE inhibitor Ro 32-7315, whose affinity for the beta subunit (IC50=1.6 mM) is weaker by three orders of magnitude than that for the alpha subunit ( K(i)=1.6 microM). MMP inhibitors such as the pyrimidine-2,4,6-trione derivative Ro 28-2653 that are more specific for gelatinases do not bind to hMeprin, presumably due to the subtle differences in the mode of zinc binding and active-site structure between the astacins and the MMPs.
-
phorbol 12 myristate 13 acetate induced ectodomain shedding and phosphorylation of the human Meprinβ metalloprotease
Journal of Biological Chemistry, 2003Co-Authors: Dagmar Hahn, Boris Leuenberger, Anastassios Pischitzis, Marianne K Hansen, Sandra Roesmann, Ursula Luginbuehl, Erwin E SterchiAbstract:Abstract Shedding of proteins localized at the cell surface is an important regulatory step in the function of many of these proteins. Human Meprin (N-benzoyl-l-tyrosyl-p-aminobenzoic acid hydrolase, PPH, EC 3.4.24.18) a zinc-metalloendopeptidase of the astacin family is an oligomeric protein complex of α- and β-subunits and is expressed abundantly in the intestine and kidney as well as in leukocytes of the lamina propria and in cancer cells. In transfected cells intracellular proteolytic removal of the membrane anchor results in the secretion of the Meprin α-subunit. In rats and mice, the β-subunit exists in a membrane-anchored form. In contrast, human Meprinβ is constitutively converted into a secretable form. We now show that phorbol 12-myristate 13-acetate (PMA) stimulates an increased release of hMeprinβ from transfected COS-1 cells, whereas hMeprinα secretion is not influenced. This stimulatory effect is inhibited by the protein kinase C (PKC) inhibitor staurosporine, suggesting that activation of PKC mediates PMA-induced hMeprinβ shedding. The use of different protease inhibitors shows that two different metalloprotease activities are responsible for the constitutive and the PMA-stimulated hMeprinβ shedding. We identified tumor necrosis factor α-converting enzyme (TACE or ADAM17) as the protease that mediates the PMA-induced release. We also demonstrate that hMeprinβ is phosphorylated by PMA treatment on Ser687 within a PKC consensus sequence in the cytosolic domain of the protein. This phosphorylation of hMeprinβ is not, however, implicated in the enhanced secretion by PMA treatment.
Elimelda Moige Ongeri - One of the best experts on this subject based on the ideXlab platform.
-
Meprin β activity modulates the β catalytic subunit of protein kinase a in ischemia reperfusion induced acute kidney injury
American Journal of Physiology-renal Physiology, 2020Co-Authors: Faihaa Ahmed, Jean-marie Mwiza, Mizpha Fernander, Ismaila Yahaya, Shaymaa Abousaad, Elimelda Moige OngeriAbstract:Meprin metalloproteases have been implicated in the progression of kidney injury. Previous work from our group has shown that Meprins proteolytically process the catalytic subunit of protein kinase...
-
Meprin β metalloproteases associated with differential metabolite profiles in the plasma and urine of mice with type 1 diabetes and diabetic nephropathy
BMC Nephrology, 2019Co-Authors: Jessica Gooding, Faihaa Ahmed, Jean-marie Mwiza, Courtney Whitaker, Mizpha Fernander, Zach Acuff, Susan Mcritchie, Susan Sumner, Elimelda Moige OngeriAbstract:Background Meprin metalloproteases are abundantly expressed in the brush border membranes of kidney proximal tubules and small intestines. Meprins are also expressed in podocytes and leukocytes (monocytes and macrophages). Meprins are implicated in the pathophysiology of diabetic nephropathy (DN) but underlying mechanisms are not fully understood. Single nucleotide polymophisms (SNPs) in the Meprin β gene were associated with DKD in human subjects. Furthermore, Meprin α and β double deficiency resulted in more severe kidney injury and higher mortality rates in mice with Streptozotocin (STZ)-induced type 1 diabetes. Identification of Meprin substrates has provided insights on how Meprins could modulate kidney injury. Meprin targets in the kidney include extracellular matrix (ECM) proteins, modulators of inflammation, and proteins involved in the protein kinase A (PKA) and PKC signaling pathways. The current study used a global metabolomics approach to determine how Meprin β expression impacts the metabolite milieu in diabetes and DKD. Methods Low dose STZ was used to induce type 1 diabetes in 8-week old wild-type (WT) and Meprin β knockout (βKO) mice. Blood and urine samples were obtained at 4 and 8 weeks post-STZ injection. Assays for albumin, creatinine, neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule − 1 (KIM-1), and cystatin C were used for biochemical assessment of kidney injury. Data for biomarkers of kidney injury utilized two-way ANOVA. Metabolomics data analysis utilized UPLC-QTOF MS and multivariate statistics. Results The number of metabolites with diabetes-associated changes in levels were significantly higher in the WT mice when compared to Meprin βKO counterparts. Annotated Meprin β expression-associated metabolites with strong variable importance in projection (VIP) scores play roles in lipid metabolism (LysoPC(16:1(9Z)), taurocholic acid), amino acid metabolism (indoxyl sulfate, hippuric acid), and neurotransmitter/stress hormone synthesis (cortisol, 3-methoxy-4-hydroxyphenylethylene glycolsulfate, homovanillic acid sulfate). Metabolites that associated with Meprin β deficiency include; 3,5-dihydroxy-3′,4′-dimethoxy-6,7-methylenedioxyflavone 3-glucuronide, pantothenic acid, and indoxyl glucuronide (all decreased in plasma). Conclusion Taken together, the annotated metabolites suggest that Meprin β impacts complications of diabetes such as DKD by altering distinct metabolite profiles.
-
Meprin Metalloprotease Deficiency Associated with Higher Mortality Rates and More Severe Diabetic Kidney Injury in Mice with STZ-Induced Type 1 Diabetes
Hindawi Limited, 2017Co-Authors: John E Bylander, Faihaa Ahmed, Sabena M. Conley, Jean-marie Mwiza, Elimelda Moige OngeriAbstract:Meprins are membrane-bound and secreted metalloproteinases consisting of α and/or β subunits that are highly expressed in kidney epithelial cells and are differentially expressed in podocytes and leukocytes (macrophages and monocytes). Several studies have implicated Meprins in the progression of diabetic nephropathy (DN) and fibrosis-associated kidney disease. However, the mechanisms by which Meprins modulate DN are not understood. To delineate the role of Meprins in DN, we subjected Meprin αβ knockout (αβKO) mice and their wild-type (WT) counterparts to streptozotocin-induced type 1 diabetes. The 18-week survival rates were significantly lower for diabetic Meprin αβKO mice when compared to those for their WT counterparts. There were significant decreases in mRNA and protein levels for both Meprin α and β in diabetic WT kidneys. Furthermore, the blood urea nitrogen levels and urine albumin/creatinine ratios increased in diabetic Meprin αβKO but not in diabetic WT mice, indicating that Meprins may be protective against diabetic kidney injury. The brush border membrane levels of villin, a Meprin target, significantly decreased in diabetic WT but not in diabetic Meprin αβKO kidneys. In contrast, isoform-specific increases in cytosolic levels of the catalytic subunit of PKA, another Meprin target, were demonstrated for both WT and Meprin αβKO kidneys
-
Hypoxia Associated Proteolytic Processing of OS-9 by the Metalloproteinase Meprin β
Hindawi Limited, 2016Co-Authors: Barry Lee Martin, Jeanmarie V Niyitegeka, Sabena Michelle Conley, Regine Simone Harris, Corshe Devon Stanley, Elimelda Moige OngeriAbstract:Meprin metalloproteases play a role in the pathology of ischemia/reperfusion- (IR-) induced renal injury. The endoplasmic reticulum-associated protein, osteosarcoma-9 (OS-9), has been shown to interact with the carboxyl-terminal tail of Meprin β. More importantly, OS-9 interacts with the hypoxia inducible factor-1α (HIF-1α) and the prolyl-hydroxylase, proteins which mediate the cell’s response to hypoxia. To determine if OS-9 is a Meprin substrate, kidney proteins from Meprin αβ knockout mice (αβKO) (which lack endogenous Meprins) and purified human OS-9 were incubated with activated forms of Meprin A and Meprin B, and Western blot analysis was used to evaluate proteolytic processing of OS-9. Fragmentation of OS-9 was observed in reactions with Meprin B, but not Meprin A. To determine whether Meprin B cleaves OS-9 in vivo, wild-type (WT) and Meprin αβKO mice were subjected to IR-induced renal injury. Fragmentation of OS-9 was observed in kidney proteins from WT mice subjected to IR, but not in Meprin αβKO counterparts. Transfection of kidney cells (MDCK and HEK293) with Meprin β cDNA prevented accumulation of OS-9 following exposure to the hypoxia mimic, CoCl2. These data suggest that Meprin β interaction with OS-9 plays a role in the hypoxia response associated with IR-induced renal injury
-
isoform specific interactions between Meprin metalloproteases and the catalytic subunit of protein kinase a significance in acute and chronic kidney injury
American Journal of Physiology-renal Physiology, 2015Co-Authors: Jeanmarie V Niyitegeka, Adam C Bastidas, Robert H Newman, Susan S Taylor, Elimelda Moige OngeriAbstract:Meprin metalloproteases are abundantly expressed in the brush-border membranes of kidney proximal tubules. Meprins are implicated in ischemia-reperfusion (IR)-induced renal injury and diabetic nephropathy. The protein kinase A (PKA) signaling pathway modulates extracellular matrix metabolism in diabetic kidneys. The present study evaluated isoform-specific interactions between the catalytic subunit of PKA (PKA C) and Meprins. To this end, cytosolic-enriched kidney proteins from Meprin αβ double knockout mice, and purified forms of recombinant mouse PKA Cα, Cβ1, and Cβ2, were incubated with activated forms of either homomeric Meprin A or Meprin B. The cleaved protein products were subjected to SDS-PAGE and analyzed by Coomassie staining and Western blot analysis. While Meprin A only cleaved PKA Cβ1, Meprin B cleaved all three PKA C isoforms. Analysis of the proteolytic fragments by mass spectrometry revealed that Meprin A and B cleave the PKA C isoforms at defined sites, resulting in unique cleavage products. Michaelis-Menten enzyme kinetics demonstrated that Meprin B-mediated cleavage of PKA Cα occurs at a rate consistent with that of other physiologically relevant Meprin substrates. Meprin cleavage decreased the kinase activity of PKA Cα, Cβ1, and Cβ2. PKA C levels were higher in diabetic kidneys, with evidence of in vivo fragmentation in wild-type diabetic kidneys. Confocal microscopy showed localization of Meprin A in the glomeruli of diabetic kidneys. At 3 h post-IR, PKA C levels in proximal tubules decreased compared with distal tubules, which lack Meprins. These data suggest that Meprins may impact kidney injury, in part, via modulation of PKA signaling pathways.
Gur P. Kaushal - One of the best experts on this subject based on the ideXlab platform.
-
role of Meprin metalloproteinases in cytokine processing and inflammation
Cytokine, 2019Co-Authors: Christian Herzog, Randy S Haun, Gur P. KaushalAbstract:Meprin metalloendopeptidases, comprising α and β isoforms, are widely expressed in mammalian cells and organs including kidney, intestines, lungs, skin, and bladder, and in a variety of immune cells and cancer cells. Meprins proteolytically process many inflammatory mediators, including cytokines, chemokines, and other bioactive proteins and peptides that control the function of immune cells. The knowledge of Meprin-mediated processing of inflammatory mediators and other target substrates provides a pathophysiologic link for the involvement of Meprins in the pathogenesis of many inflammatory disorders. Meprins are now known to play important roles in inflammatory diseases including acute kidney injury, sepsis, urinary tract infections, bladder inflammation, and inflammatory bowel disease. The proteolysis of epithelial and endothelial barriers including cell junctional proteins by Meprins promotes leukocyte influx into areas of tissue damage to result in inflammation. Meprins degrade extracellular matrix proteins; this ability of Meprins is implicated in the cell migration of leukocytes and the invasion of tumor cells that express Meprins. Proteolytic processing and maturation of procollagens provides evidence that Meprins are involved in collagen maturation and deposition in the fibrotic processes involved in the formation of keloids and hypertrophic scars and lung fibrosis. This review highlights recent progress in understanding the role of Meprins in inflammatory disorders in both human and mouse models.
-
Proteolytic processing and inactivation of CCL2/MCP-1 by Meprins.
Biochemistry and biophysics reports, 2016Co-Authors: Christian Herzog, Sudhir V Shah, Randy S Haun, Gur P. KaushalAbstract:Monocyte chemotactic protein 1 (CCL2/MCP-1) is a small chemokine involved in the recruitment and trafficking of mononuclear immune cells to inflammation sites. Our studies demonstrate that the metalloendopeptidases Meprin A (purified from kidney cortex), recombinant Meprin α, and recombinant Meprin β can all process CCL2/MCP-1. The cleavage sites were determined by amino acid sequencing and mass spectrometry analysis of the generated products, and the biological activity of the products was evaluated by chemotactic migration assay using THP-1 cells. The cleavage sites generated by the Meprin isoforms revealed that Meprin A and Meprin α cleaved the N-terminal domain of mouse CCL2/MCP-1 at the Asn6 and Ala7 bond, resulting in significant reduction in the chemotactic activity of the cleaved CCL2/MCP-1. Meprin β was unable to cleave the N-terminus of mouse CCL2/MCP-1 but cleaved the C-terminal region between Ser74 and Glu75. Human CCL2/MCP-1 that lacks the murine C-terminal region was also cleaved by Meprin α at the N-terminus resulting in significant loss of CCL2/MCP-1 biological activity, whereas Meprin β did not affect the biological activity. These studies suggest that Meprin α and Meprin β may play important roles in regulating the CCL2/MCP-1 chemokine activity during inflammation.
-
basement membrane protein nidogen 1 is a target of Meprin β in cisplatin nephrotoxicity
Toxicology Letters, 2015Co-Authors: Christian Herzog, Randy S Haun, Raju Marisiddaiah, Gur P. KaushalAbstract:Meprins are oligomeric metalloproteinases that are abundantly expressed in the brush-border membranes of renal proximal tubules. During acute kidney injury (AKI) induced by cisplatin or ischemia-reperfusion, membrane-bound Meprins are shed and their localization is altered from the apical membranes toward the basolateral surface of the proximal tubules. Meprins are capable of cleaving basement membrane proteins in vitro, however, it is not known whether Meprins are able to degrade extracellular matrix proteins under pathophysiological conditions in vivo. The present study demonstrates that a basement membrane protein, nidogen-1, is cleaved and excreted in the urine of mice subjected to cisplatin-induced nephrotoxicity, a model of AKI. Cleaved nidogen-1 was not detected in the urine of untreated mice, but during the progression of cisplatin nephrotoxicity, the excretion of cleaved nidogen-1 increased in a time-dependent manner. The Meprin inhibitor actinonin markedly prevented urinary excretion of the cleaved nidogen-1. In addition, Meprin β-deficient mice, but not Meprin α-deficient mice, subjected to cisplatin nephrotoxicity significantly suppressed excretion of cleaved nidogen-1, further suggesting that Meprin β is involved in the cleavage of nidogen-1. These studies provide strong evidence for a pathophysiological link between Meprin β and urinary excretion of cleaved nidogen-1 during cisplatin-induced AKI.
-
adam10 is the major sheddase responsible for the release of membrane associated Meprin a
Journal of Biological Chemistry, 2014Co-Authors: C. Herzog, Andreas Ludwig, Randy S Haun, Sudhir V Shah, Gur P. KaushalAbstract:Meprin A, composed of α and β subunits, is a membrane-bound metalloproteinase in renal proximal tubules. Meprin A plays an important role in tubular epithelial cell injury during acute kidney injury (AKI). The present study demonstrated that during ischemia-reperfusion-induced AKI, Meprin A was shed from proximal tubule membranes, as evident from its redistribution toward the basolateral side, proteolytic processing in the membranes, and excretion in the urine. To identify the proteolytic enzyme responsible for shedding of Meprin A, we generated stable HEK cell lines expressing Meprin β alone and both Meprin α and Meprin β for the expression of Meprin A. Phorbol 12-myristate 13-acetate and ionomycin stimulated ectodomain shedding of Meprin β and Meprin A. Among the inhibitors of various proteases, the broad spectrum inhibitor of the ADAM family of proteases, tumor necrosis factor-α protease inhibitor (TAPI-1), was most effective in preventing constitutive, phorbol 12-myristate 13-acetate-, and ionomycin-stimulated shedding of Meprin β and Meprin A in the medium of both transfectants. The use of differential inhibitors for ADAM10 and ADAM17 indicated that ADAM10 inhibition is sufficient to block shedding. In agreement with these results, small interfering RNA to ADAM10 but not to ADAM9 or ADAM17 inhibited Meprin β and Meprin A shedding. Furthermore, overexpression of ADAM10 resulted in enhanced shedding of Meprin β from both transfectants. Our studies demonstrate that ADAM10 is the major ADAM metalloproteinase responsible for the constitutive and stimulated shedding of Meprin β and Meprin A. These studies further suggest that inhibiting ADAM 10 activity could be of therapeutic benefit in AKI.
-
Meprin a and Meprin α generate biologically functional il 1β from pro il 1β
Biochemical and Biophysical Research Communications, 2009Co-Authors: Christian Herzog, Philip R Mayeux, Randy S Haun, Sudhir V Shah, Varsha Kaushal, Gur P. KaushalAbstract:Abstract The present study demonstrates that both oligomeric metalloendopeptidase Meprin A purified from kidney cortex and recombinant Meprin α are capable of generating biologically active IL-1β from its precursor pro-IL-1β. Amino-acid sequencing analysis reveals that Meprin A and Meprin α cleave pro-IL-1β at the His 115 -Asp 116 bond, which is one amino acid N-terminal to the caspase-1 cleavage site and five amino acids C-terminal to the Meprin β site. The biological activity of the pro-IL-1β cleaved product produced by Meprin A, determined by proliferative response of helper T-cells, was 3-fold higher to that of the IL-1β product produced by Meprin β or caspase-1. In a mouse model of sepsis induced by cecal ligation puncture that results in elevated levels of serum IL-1β, Meprin inhibitor actinonin significantly reduces levels of serum IL-1β. Meprin A and Meprin α may therefore play a critical role in the production of active IL-1β during inflammation and tissue injury.