Stimulation of Fibronectin Matrix Assembly by Lysine Acetylation

Diabetic nephropathy, a devastating consequence of diabetes mellitus, is characterized by the accumulation of extracellular matrix (ECM) that disrupts the kidney’s filtration apparatus. Elevated glucose levels increase the deposition of a fibronectin (FN) matrix by mesangial cells, the primary matrix-producing cells of the kidney, and also increase acetyl-CoA leading to higher levels of lysine acetylation. Here, we investigated the connection between acetylation and the ECM and show that treatment of mesangial cells with deacetylase inhibitors increases both acetylation and FN matrix assembly compared to untreated cells. The matrix effects were linked to lysine 794 (K794) in the β1 integrin cytoplasmic domain based on studies of cells expressing acetylated (K794Q) and non-acetylated (K794R) mimetics. β1(K794Q) cells assembled significantly more FN matrix than wildtype β1 cells, while the non-acetylated β1(K794R) form was inactive. We show that mutation of K794 affects FN assembly by stimulating integrin-FN binding activity and cell contractility. Wildtype and β1(K794Q) cells but not β1(K794R) cells further increased their FN matrix when stimulated with deacetylase inhibitors indicating that increased acetylation on other proteins is required for maximum FN assembly. Thus, lysine acetylation provides a mechanism for glucose-induced fibrosis by up-regulation of FN matrix assembly.

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Effects of high glucose on integrin activity and fibronectin matrix assembly by mesangial cells

Molecular Biology of the Cell ◽

10.1091/mbc.e14-03-0800 ◽

2014 ◽

Vol 25 (16) ◽

pp. 2342-2350 ◽

Cited By ~ 42

Author(s):

Charles G. Miller ◽

Ambra Pozzi ◽

Roy Zent ◽

Jean E. Schwarzbauer

Keyword(s):

High Glucose ◽

Mesangial Cells ◽

Collagen Iv ◽

Matrix Assembly ◽

Protein Levels ◽

Type Iv ◽

The Matrix ◽

Normal Glucose ◽

Elevated Glucose ◽

Filtration Unit

The filtration unit of the kidney is the glomerulus, a capillary network supported by mesangial cells and extracellular matrix (ECM). Glomerular function is compromised in diabetic nephropathy (DN) by uncontrolled buildup of ECM, especially type IV collagen, which progressively occludes the capillaries. Increased levels of the ECM protein fibronectin (FN) are also present; however, its role in DN is unknown. Mesangial cells cultured under high glucose conditions provide a model system for studying the effect of elevated glucose on deposition of FN and collagen IV. Imaging of mesangial cell cultures and analysis of detergent-insoluble matrix show that, under high glucose conditions, mesangial cells assembled significantly more FN matrix, independent of FN protein levels. High glucose conditions induced protein kinase C–dependent β1 integrin activation, and FN assembly in normal glucose was increased by stimulation of integrin activity with Mn2+. Collagen IV incorporation into the matrix was also increased under high glucose conditions and colocalized with FN fibrils. An inhibitor of FN matrix assembly prevented collagen IV deposition, demonstrating dependence of collagen IV on FN matrix. We conclude that high glucose induces FN assembly, which contributes to collagen IV accumulation. Enhanced assembly of FN might facilitate dysregulated ECM accumulation in DN.

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Induction of fibronectin matrix assembly in human fibrosarcoma cells by dexamethasone.

The Journal of Cell Biology ◽

10.1083/jcb.104.3.601 ◽

1987 ◽

Vol 104 (3) ◽

pp. 601-610 ◽

Cited By ~ 38

Author(s):

P J McKeown-Longo ◽

C A Etzler

Keyword(s):

Extracellular Matrix ◽

Surface Protein ◽

Order Rate Constant ◽

Binding Activity ◽

Matrix Assembly ◽

Cultured Fibroblasts ◽

Fibrosarcoma Cells ◽

The Matrix ◽

Fibronectin Binding ◽

Human Fibrosarcoma Cells

Previous studies have suggested that the assembly of fibronectin into the extracellular matrix of cultured fibroblasts is mediated by specific matrix assembly receptors that recognize a binding site in the amino terminus of the fibronectin molecule (McKeown-Longo, P.J., and D.F. Mosher, 1985, J. Cell Biol., 100:364-374). In the presence of dexamethasone, human fibrosarcoma cells (HT-1080) acquired the ability to specifically bind exogenous plasma fibronectin and incorporate it into a detergent-insoluble extracellular matrix. Dexamethasone-induced fibronectin binding to HT-1080 cells was time dependent, dose dependent, and inhibited by cycloheximide. Saturation binding curves indicated that dexamethasone induced the appearance of 7.7 X 10(4) matrix assembly receptors per cell. The induced receptors exhibited a dissociation constant (KD) for soluble fibronectin of 5.0 X 10(-8) M. In parallel experiments, normal fibroblasts exhibited 4.1 X 10(5) receptors (KD = 5.3 X 10(-8) M) per cell. In the presence of cycloheximide, the induced fibronectin-binding activity on HT-1080 cells returned to uninduced levels within 12 h. In contrast, fibronectin-binding activity on normal fibroblasts was stable in the presence of cycloheximide for up to 54 h. The first-order rate constant (Kt = 2.07 X 10(-4) min-1) for the transfer of receptor-bound fibronectin to extracellular matrix was four- to fivefold less than that for normal fibroblasts (Kt = 1.32 X 10(-3) min-1). Lactoperoxidase-catalyzed iodination of HT-1080 monolayers indicated that a 48,000-mol-wt cell surface protein was enhanced with dexamethasone. The results from these experiments suggest that dexamethasone induces functional matrix assembly receptors on the surface of HT-1080 cells; however, the rate of incorporation of fibronectin into the matrix is much slower than that of normal fibroblasts.

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Enhanced expression of group IIA secreted phospholipase A2 by elevated glucose levels in cytokine-stimulated rat mesangial cells and in kidneys of diabetic rats

Clinical Nephrology ◽

10.5414/cnp63356 ◽

2005 ◽

Vol 63 (05) ◽

pp. 356-367 ◽

Cited By ~ 5

Author(s):

G.J. Vlachojannis ◽

K. Scholz-Pedretti ◽

W. Fierlbeck ◽

H. Geiger ◽

J. Pfeilschifter ◽

...

Keyword(s):

Phospholipase A2 ◽

Mesangial Cells ◽

Diabetic Rats ◽

Glucose Levels ◽

Secreted Phospholipase A2 ◽

Enhanced Expression ◽

Elevated Glucose

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Enhanced Expression of Inducible Nitric Oxide Synthase in Murine Macrophages and Glomerular Mesangial Cells by Elevated Glucose Levels: Possible Mediation via Protein Kinase C

Biochemical and Biophysical Research Communications ◽

10.1006/bbrc.1995.1156 ◽

1995 ◽

Vol 207 (1) ◽

pp. 80-88 ◽

Cited By ~ 78

Author(s):

K. Sharma ◽

T.M. Danoff ◽

A. Depiero ◽

F.N. Ziyadeh

Keyword(s):

Nitric Oxide ◽

Protein Kinase C ◽

Mesangial Cells ◽

Glomerular Mesangial Cells ◽

Glucose Levels ◽

Kinase C ◽

Enhanced Expression ◽

Elevated Glucose ◽

Oxide Synthase ◽

Inducible Nitric Oxide

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Effect of Elevated Glucose on Endothelin-Induced Store-Operated and Non-Store-Operated Calcium Influx in Renal Mesangial Cells

Journal of the American Society of Nephrology ◽

10.1681/asn.v1171225 ◽

2000 ◽

Vol 11 (7) ◽

pp. 1225-1235

Author(s):

LETA K. NUTT ◽

ROGER G. O'NEIL

Keyword(s):

Calcium Signaling ◽

High Glucose ◽

Mesangial Cells ◽

Calcium Influx ◽

Calcium Entry ◽

Calcium Signal ◽

Glomerular Mesangial Cells ◽

Glucose Levels ◽

Elevated Glucose ◽

Acute And Chronic Exposure

Abstract. Early diabetic nephropathy exhibits renal glomerular hyperfiltration and an increase in renal plasma flow. The hyperfiltration is a dysfunctional state that may arise from a hyperglycemic-induced hypocontractility of glomerular mesangial cells that may be associated with depressed Ca2+signaling events. The present study was designed to determine the effects of acute (minutes) and chronic (days) elevated glucose levels on endothelin-induced calcium signaling with a particular emphasis on the potential influence on stores and store-operated Ca2+influx (SOCI ; also called capacitative calcium entry) in glomerular mesangial cells. Primary cultures of rat mesangial cells were grown in either high (30 mM) or normal (5 mM) glucose-containing media and tested in the presence of either high (30 mM) or normal (5 mM) glucose levels. Intracellular calcium levels were monitored with the calcium-sensitive fluorophore fura-2 before and after treatment with either endothelin-1 (10 nM), to induce typical Ca2+signals, or the endoplasmic reticulum (ER) Ca-ATPase inhibitor thapsagargin (1 μM), to unload ER Ca2+stores. Both acute and chronic exposure to high glucose levels depressed the endothelin-induced calcium signal. However, neither release of Ca2+from stores nor SOCI were depressed by high glucose levels. In contrast, an endothelin-induced calcium entry pathway (likely receptor-operated calcium influx), separate from SOCI, was markedly depressed in the presence of both acute and chronic high glucose levels. The depressant effect of high glucose was rapidly (minutes) reversible upon returning to normal glucose levels. It is concluded that high glucose levels depress endothelin-induced calcium signaling in rat mesangial cells by inhibiting non-SOCI Ca2+entry pathways, namely the receptor-operated Ca2+influx pathway. The glucose-induced alterations in the receptor-operated calcium influx pathway may, in part, contribute to the depressed contractile state of glomerular cells during periods of hyperglycemia.

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Trigonelline regulates Wnt/β-catenin signaling in glomerular mesangial cells under high glucose conditions

10.21203/rs.3.rs-419018/v1 ◽

2021 ◽

Author(s):

Chen Chen ◽

Yan Shi ◽

Zhen Chen ◽

Xiangjun Li ◽

Bo Sun ◽

...

Keyword(s):

Cell Cycle ◽

Flow Cytometry ◽

High Glucose ◽

Cell Cycle Progression ◽

Cell Injury ◽

Mesangial Cells ◽

Animal Experiments ◽

Glomerular Mesangial Cells ◽

Glucose Levels ◽

Elevated Glucose

Abstract Background: Trigonelline have hypoglycemic effects. In previous animal experiments, we observed that trigonelline (TRL) treat-ment attenuated metabolic abnormalities associated with hyperglycemic conditions in the experimental DN model. In streptozotocin (STZ)-induced rats, TRL treatment reduced albuminuria, lowered blood sugar, improved renal function and alleviated the pathological alterations within the glomerulus. Methods: We stimulated human mesangial cells (HMC) with high glucose (30 mmol / L) medium. HMCs were transfected with β-catenin plasmid or siRNA to investigate the effect of trigonelline on high glucose-induced excessive proliferation and apoptosis of HMCs, and to understand its mechanism of action. Cell viability was measured by MTT assay. Flow cytometry was used to detect the cell cycle. Cell apoptosis was evaluated by flow cytometry and terminal dUTP transferase nick end labeling (TUNEL) assay. Protein and mRNA expression of β-catenin, Wnt5a, TCF4, Cyclin D1, and CDK4 were detected by western blotting and RT-PCR, respectively. Results: Trigonelline inhibited cell proliferation by blocking cell-cycle progression at the G1 phase and decreased apoptosis via the Wnt/β-catenin pathway. Elevated glucose levels enhanced the expression of β-catenin, an important modulator of diabetic nephropathy, while trigonelline restored up-regulation. Conclusions: High glucose and high expression of β-catenin could lead to cell injury; however, this effect was mitigated by trigonelline via managing the canonical Wnt/β-catenin signaling pathway.

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Effects of pH and Elevated Glucose Levels on the Electrochemical Behaviour of Dental Implants

Journal of Oral Implantology ◽

10.1563/aaid-joi-d-11-00083.1 ◽

2012 ◽

pp. 120229132049008 ◽

Cited By ~ 3

Author(s):

Evsen Tamam ◽

Ilser Turkyilmaz

Keyword(s):

Dental Implants ◽

Electrochemical Behaviour ◽

Glucose Levels ◽

Effects Of Ph ◽

Elevated Glucose

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Induction of resistance to endothelin-1's biochemical actions by elevated glucose levels in retinal pericytes

Diabetes ◽

10.2337/diabetes.41.12.1533 ◽

1992 ◽

Vol 41 (12) ◽

pp. 1533-1539 ◽

Cited By ~ 22

Author(s):

G. de la Rubia ◽

F. J. Oliver ◽

T. Inoguchi ◽

G. L. King

Keyword(s):

Endothelin 1 ◽

Glucose Levels ◽

Retinal Pericytes ◽

Elevated Glucose ◽

Induction Of Resistance

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Gpr1 is an active chemerin receptor influencing glucose homeostasis in obese mice

Journal of Endocrinology ◽

10.1530/joe-14-0069 ◽

2014 ◽

Vol 222 (2) ◽

pp. 201-215 ◽

Cited By ~ 52

Author(s):

Jillian L Rourke ◽

Shanmugam Muruganandan ◽

Helen J Dranse ◽

Nichole M McMullen ◽

Christopher J Sinal

Keyword(s):

Adipose Tissue ◽

Glucose Homeostasis ◽

Stromal Vascular Fraction ◽

Tolerance Test ◽

Glucose Levels ◽

Brown Adipose ◽

Elevated Glucose ◽

And Function ◽

G Protein Coupled

Chemerin is an adipose-derived signaling protein (adipokine) that regulates adipocyte differentiation and function, immune function, metabolism, and glucose homeostasis through activation of chemokine-like receptor 1 (CMKLR1). A second chemerin receptor, G protein-coupled receptor 1 (GPR1) in mammals, binds chemerin with an affinity similar to CMKLR1; however, the function of GPR1 in mammals is essentially unknown. Herein, we report that expression of murineGpr1mRNA is high in brown adipose tissue and white adipose tissue (WAT) and skeletal muscle. In contrast to chemerin (Rarres2) andCmklr1,Gpr1expression predominates in the non-adipocyte stromal vascular fraction of WAT. Heterozygous and homozygousGpr1-knockout mice fed on a high-fat diet developed more severe glucose intolerance than WT mice despite having no difference in body weight, adiposity, or energy expenditure. Moreover, mice lackingGpr1exhibited reduced glucose-stimulated insulin levels and elevated glucose levels in a pyruvate tolerance test. This study is the first, to our knowledge, to report the effects ofGpr1deficiency on adiposity, energy balance, and glucose homeostasisin vivo. Moreover, these novel results demonstrate that GPR1 is an active chemerin receptor that contributes to the regulation of glucose homeostasis during obesity.

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