scholarly journals Cellular activation of mesangial gelatinase A by cytochalasin D is accompanied by enhanced mRNA expression of both gelatinase A and its membrane-associated gelatinase A activator (MT-MMP)

1996 ◽  
Vol 313 (3) ◽  
pp. 879-884 ◽  
Author(s):  
Menachem AILENBERG ◽  
Mel SILVERMAN
Keyword(s):  
Mesangial Cells ◽  
Rat Kidney ◽  
State Level ◽  
Enzymic Activity ◽  
Cytochalasin D ◽  
Gelatinase A ◽  
Cellular Activation ◽  
Reverse Transcription Pcr ◽  
Extracellular Compartment ◽  
Membrane Type

Activation of gelatinase A represents a crucial regulatory step in the control of its enzymic activity. Rat kidney mesangial cells secrete predominantly latent gelatinase A that can be activated following treatment with cytochalasin D. In the present paper we provide new evidence, using reverse transcription-PCR, that treatment of rat mesangial cells with cytochalasin D enhances the steady-state level of mRNA of the membrane-type matrix metalloproteinase (MT-MMP), as well as of gelatinase A, with no change in the level of tissue inhibitor of metalloproteinases-2 (TIMP-2) mRNA. Since the TIMP-2 protein level is reduced in conditioned medium from cytochalasin D-treated cells, the results of the present study are consistent with a model in which the action of cytochalasin D is to cause extracellular gelatinase A and TIMP-2 to be sequestered at the plasma membrane, forming a heterotrimeric complex with MT-MMP. In this manner, TIMP-2 may assume a bifunctional role causing: (i) inhibition of gelatinase A in the extracellular compartment; and (ii) guiding gelatinase A to activation through a membrane association with MT-MMP.

scholarly journals Cellular Distribution and Function of Soluble Guanylyl Cyclase in Rat Kidney and Liver

2001 ◽  
Vol 12 (11) ◽  
pp. 2209-2220 ◽  
Author(s):  
FRANZISKA THEILIG ◽  
MAGDALENA BOSTANJOGLO ◽  
HERMANN PAVENSTÄDT ◽  
CLEMENS GRUPP ◽  
GUDRUN HOLLAND ◽  
...  
Keyword(s):  
Guanylyl Cyclase ◽  
Mesangial Cells ◽  
Rat Kidney ◽  
Soluble Guanylyl Cyclase ◽  
No Donor ◽  
Ito Cells ◽  
Reverse Transcription Pcr ◽  
Cgmp Signaling ◽  
And Function

Abstract. Soluble guanylyl cyclase (sGC) catalyzes the biosynthesis of cGMP in response to binding of L-arginine-derived nitric oxide (NO). Functionally, the NO-sGC-cGMP signaling pathway in kidney and liver has been associated with regional hemodynamics and the regulation of glomerular parameters. The distribution of the ubiquitous sGC isoform α1β1 sGC was studied with a novel, highly specific antibody against the β1 subunit. In parallel, the presence of mRNA encoding both subunits was investigated by using in situ hybridization and reverse transcription-PCR assays. The NO-induced, sGC-dependent accumulation of cGMP in cytosolic extracts of tissues and cells was measured in vitro. Renal glomerular arterioles, including the renin-producing granular cells, mesangium, and descending vasa recta, as well as cortical and medullary interstitial fibroblasts, expressed sGC. Stimulation of isolated mesangial cells, renal fibroblasts, and hepatic Ito cells with a NO donor resulted in markedly increased cytosolic cGMP levels. This assessment of sGC expression and activity in vascular and interstitial cells of kidney and liver may have implications for understanding the role of local cGMP signaling cascades.

scholarly journals Tumour metastasis suppressor, nm23-β, inhibits gelatinase A transcription by interference with transactivator Y-box protein-1 (YB-1)

2002 ◽  
Vol 366 (3) ◽  
pp. 807-816 ◽  
Author(s):  
Sunfa CHENG ◽  
Maria Alexandra ALFONSO-JAUME ◽  
Peter R. MERTENS ◽  
David H. LOVETT
Keyword(s):  
Mesangial Cells ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Repeat Sequence ◽  
Luciferase Reporter ◽  
Metastasis Suppressor ◽  
Gelatinase A ◽  
Glomerular Mesangial Cells ◽  
Tumour Metastasis ◽  
Β Protein

Gelatinase A transcriptional regulation is the consequence of combinatorial interactions with key promoter and enhancer elements identified within this gene. A potent 40bp enhancer response element, RE-1, located in the near 5′ flanking regions of the rat and human gelatinase A genes drives high-level expression in glomerular mesangial cells (MCs). Southwestern-blot analysis of MC nuclear extracts revealed specific interactions of RE-1 with at least four proteins, of which three have been identified as p53, activator protein 2 and the single-stranded DNA-binding factor Y-box protein-1 (YB-1). In the present study, we report the identification of a fourth 17kDa RE-1-binding protein as the rat homologue (nm23-β) of the human nm23-H1 metastasis suppressor gene. Recombinant nm23-β protein bound only the single-stranded forms of the RE-1 sequence. Mutagenesis revealed direct interaction of nm23-β with a repeat sequence, 5′-GGGTTT-3′, shown previously to specifically interact with YB-1 [Mertens, Harendza, Pollock and Lovett (1997) J. Biol. Chem. 272, 22905—22912], and recombinant nm23-β protein competed for single-stranded YB-1 binding. Transient transfection of MC with an nm23-β expression plasmid within the context of a RE-1/simian virus 40 promoter/luciferase reporter yielded a concentration-dependent repression (80—90%) of luciferase activity in MC and Rat1 fibroblasts. A similar pattern of nm23-β repression was demonstrated within the context of the RE-1/homologous gelatinase A promoter. Co-transfection of nm23-β blocked YB-1-mediated activation of transcription and expression of gelatinase A. Nm23-β may be an important physiological regulator of gelatinase A transcription that acts by competitive interference with the single-stranded transactivator YB-1. Gelatinase A is a key mediator of tumour metastasis, suggesting that competitive suppression of transcription by nm23-β (or the human nm23-H1) may be a component of the reduced metastatic capabilities of cells expressing high levels of this protein.

Effects of epidermal growth factor on collagen expression by rat kidney mesangial cells in culture

2000 ◽  
Vol 19 (1) ◽  
pp. 47-59 ◽  
Author(s):  
Michael A. Haralson ◽  
Samuel J. DiMari ◽  
Richard L. Hoover ◽  
Raymond C. Harris
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Mesangial Cells ◽  
Rat Kidney ◽  
Cells In Culture ◽  
Collagen Expression ◽  
Epidermal Growth

Myo-inositol and D-glucose transport in rat glomerular and cultured mesangial cells

1991 ◽  
Vol 260 (1) ◽  
pp. F138-F144 ◽  
Author(s):  
C. I. Whiteside ◽  
J. C. Thompson ◽  
J. Ohayon
Keyword(s):  
Glucose Transport ◽  
Mesangial Cells ◽  
Intact Cell ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Cellular Transport ◽  
Sprague Dawley ◽  
Rat Kidney Cortex ◽  
Disease States ◽  
Glomerular Epithelial Cells

Myo-inositol (MI) is the precursor of membrane-bound phosphoinositides important for transmembrane signaling. This study examines whether freshly isolated whole glomeruli can be used to characterize intact cell transport kinetics for MI and D-glucose. Transport properties of cultured mesangial cells are compared. Glomeruli greater than 95% tubule free were isolated from Sprague-Dawley rat kidney cortex by means of selective sieving. Scanning electron microscopy revealed substantial damage of glomerular epithelial cells, whereas endothelial and mesangial cells remained intact. Specific [3H]MI uptake (7-180 min, 37 degrees C) was observed in presence of 5.5 mM D-glucose when L-[14C]glucose was used as a marker of nonspecific uptake. With ouabain (3 mM), or when Na was replaced with N-methyl-D-glucamine, choline, or Li, specific MI uptake was reduced by 95%. A single high-affinity, Na-dependent MI transport site on glomerular cells with Km of 16.5 +/- 1.4 (SE) microM and Vmax of 947 +/- 56 (SE) fmol.mg protein-1.min-1 was observed for 0.75-100 microM MI. D-glucose competitively inhibited MI transport. Specific D-[3H]-glucose transport was Na independent. Phlorizin inhibition of D-glucose and MI uptake was in keeping with Na-independent D-glucose transport. Km and Vmax for MI uptake in cultured mesangial cells were 42.7 +/- 7.1 microM and 1,474 +/- 192 fmol.mg protein-1.min-1, respectively. We conclude that freshly isolated glomeruli can be used to study cellular transport function that may be modified in disease states.

Urodilatin: binding properties and stimulation of cGMP generation in rat kidney cells

1993 ◽  
Vol 264 (2) ◽  
pp. F267-F273
Author(s):  
H. Saxenhofer ◽  
W. R. Fitzgibbon ◽  
R. V. Paul
Keyword(s):  
Guanylate Cyclase ◽  
Mesangial Cells ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Binding Characteristics ◽  
Papillary Collecting Duct ◽  
Collecting Duct Cells ◽  
Medullary Collecting Duct ◽  
Anp Receptors

Urodilatin (URO) [ANP-(95-126)] is an analogue of atrial natriuretic peptide (alpha-ANP) [ANP-(99-126)] that was first isolated from human urine. In rat mesangial cells, URO competed with high affinity for non-guanylate cyclase-coupled ANPR-C receptors [concentration at which 50% labeled ligand is displaced (IC50) approximately 70 pM], but with lesser affinity to the guanylate cyclase-linked ANPR-A receptors (IC50 approximately 800 pM). alpha-ANP bound to both receptors with similar affinity [dissociation constant (Kd) approximately 150 pM]. In papillary collecting duct homogenates, which possess only ANPR-A receptors, the apparent Kd value averaged 229 pM for alpha-ANP and 2.7 nM for URO. Intravenous URO was at least as potent and effective as alpha-ANP in inducing diuresis and natriuresis in anesthetized rats, but URO was approximately 10-fold less potent in stimulating guanosine 3',5'-cyclic monophosphate generation in mesangial and inner medullary collecting duct cells. We conclude that URO has a lesser affinity than alpha-ANP for guanylate cyclase-coupled ANP receptors in the kidney and that the relative natriuretic potency of URO in vivo cannot be directly attributed to its binding characteristics with ANPR-A receptors.

Hexosamines and TGF-β1 use similar signaling pathways to mediate matrix protein synthesis in mesangial cells

2004 ◽  
Vol 286 (2) ◽  
pp. F409-F416 ◽  
Author(s):  
Lalit P. Singh ◽  
Kenneith Green ◽  
Michelle Alexander ◽  
Shira Bassly ◽  
Errol D. Crook
Keyword(s):  
High Glucose ◽  
Matrix Protein ◽  
Transforming Growth Factor ◽  
Cell Function ◽  
Mesangial Cells ◽  
Rat Kidney ◽  
Protein Accumulation ◽  
Western Blots ◽  
Matrix Production ◽  
Mes Cells

Hyperglycemia-induced alterations in mesangial (MES) cell function and extracellular matrix (ECM) protein accumulation are seen in diabetic glomerulopathy. Transforming growth factor-β1 (TGF-β1) mediates high-glucose-induced matrix production in the kidney. Recent studies demonstrated that some of the effects of high glucose on cellular metabolism are mediated by the hexosamine biosynthesis pathway (HBP) in which fructose-6-phosphate is converted to glucosamine (GlcN) 6-phosphate. We previously showed that the high-glucose-mediated fibronectin and laminin synthesis in MES cells is mediated by the HBP and that GlcN is more potent than glucose in inducing TGF-β1 promoter luciferase activity. In this study, we investigated the hypothesis that the effects of glucose on MES matrix production occur via hexosamine regulation of TGF-β1. Culturing simian virus (SV)-40-transformed rat kidney MES cells in 25 mM glucose (HG) for 48 h increases cellular fibronectin and laminin levels about twofold on Western blots compared with low glucose (5 mM). GlcN (1.5 mM) or TGF-β1 (2.5-5 ng/ml) for 24-48 h also increases ECM synthesis. However, the effects of HG or GlcN with TGF-β1 are not additive. The presence of anti-TGF-β1 antibodies (20 μg/ml) blocks both TGF-β1- and GlcN-induced fibronectin synthesis. TGF-β1 increased ECM levels via PKA (laminin and fibronectin) and PKC (fibronectin) pathways. Similarly, TGF-β1 and hexosamines led to nonadditive increases in phosphorylation of the cAMP responsive element binding transcription factor. These results suggest that the effects of excess glucose on MES ECM synthesis occur via HBP-mediated regulation of TGF-β1.

Prostaglandin transporter PGT is expressed in cell types that synthesize and release prostanoids

2002 ◽  
Vol 282 (6) ◽  
pp. F1103-F1110 ◽  
Author(s):  
Yi Bao ◽  
Michael L. Pucci ◽  
Brenda S. Chan ◽  
Run Lu ◽  
Shigekazu Ito ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Mesangial Cells ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Cell Types ◽  
Proximal Tubules ◽  
Surface Epithelium ◽  
Extracellular Loop ◽  
Insight Into ◽  
Rat Platelets

PGT is a broadly expressed transporter of prostaglandins (PGs) and thromboxane that is energetically poised to take up prostanoids across the plasma membrane. To gain insight into the function of PGT, we generated mouse monoclonal antibody 20 against a portion of putative extracellular loop 5 of rat PGT. Immunoblots of endogenous PGT in rat kidney revealed a 65-kDa protein in a zonal pattern corresponding to PG synthesis rates (papilla ≅ medulla > cortex). Immunocytochemically, PGT in rat kidneys was expressed in glomerular endothelial and mesangial cells, arteriolar endothelial and muscularis cells, principal cells of the collecting duct, medullary interstitial cells, medullary vasa rectae endothelia, and papillary surface epithelium. Proximal tubules, which are known to take up and metabolize PGs, were negative. Immunoblotting and immunocytochemistry revealed that rat platelets also express abundant PGT. Coexpression of the PG synthesis apparatus (cyclooxygenase) and PGT by the same cell suggests that prostanoids may undergo release and reuptake.

scholarly journals Host PGRP Gene Expression and Bacterial Release in Endosymbiosis of the Weevil Sitophilus zeamais

2006 ◽  
Vol 72 (10) ◽  
pp. 6766-6772 ◽  
Author(s):  
Caroline Anselme ◽  
Agnès Vallier ◽  
Séverine Balmand ◽  
Marie-Odile Fauvarque ◽  
Abdelaziz Heddi
Keyword(s):  
State Level ◽  
Immune Defense ◽  
Sitophilus Zeamais ◽  
Host Immune System ◽  
Gene Transcript ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Peptidoglycan Recognition Protein ◽  
Reverse Transcription Pcr ◽  
Imd Pathway

ABSTRACT Intracellular symbiosis (endosymbiosis) with gram-negative bacteria is common in insects, yet little is known about how the host immune system perceives the endosymbionts and controls their growth and invasion without complete bacterial clearance. In this study, we have explored the expression of a peptidoglycan recognition protein gene of the weevil Sitophilus zeamais (wPGRP); an ortholog in Drosophila (i.e., PGRP-LB) was recently shown to downregulate the Imd pathway (A. Zaidman-Remy, M. Herve, M. Poidevin, S. Pili-Floury, M. S. Kim, D. Blanot, B. H. Oh, R. Ueda, D. Mengin-Lecreulx, and B. Lemaitre, Immunity 24:463-473, 2006). Insect challenges with bacteria have demonstrated that wPGRP is induced by gram-negative bacteria and that the level of induction depends on bacterial growth. Real-time reverse transcription-PCR quantification of the wPGRP gene transcript performed at different points in insect development has shown a high steady-state level in the bacteria-bearing organ (the bacteriome) of larvae and a high level of wPGRP up-regulation in the symbiotic nymphal phase. Concomitantly, during this stage fluorescence in situ hybridization has revealed an endosymbiont release from the host bacteriocytes. Together with the previously described high induction level of endosymbiont virulence genes at the nymphal phase (C. Dale, G. R. Plague, B. Wang, H. Ochman, and N. A. Moran, Proc. Natl. Acad. Sci. USA 99:12397-12402, 2002), these findings indicate that insect mutualistic relationships evolve through an interplay between bacterial virulence and host immune defense and that the host immunity engages the PGRP gene family in that interplay.

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