Insulin restores the calcium-activated chloride conductance in dedifferentiated renal glomerular mesangial cells from theH-2K B-TSA58 transgfenic mouse

1996 ◽  
Vol 432 (4) ◽  
pp. 749-751 ◽  
Author(s):  
Robert D. Barber ◽  
Robert M. Henderson
Keyword(s):  
Mesangial Cells ◽  
Chloride Conductance ◽  
Glomerular Mesangial Cells

Platelet-activating factor and the kidney

1986 ◽  
Vol 251 (1) ◽  
pp. F1-F11 ◽  
Author(s):  
D. Schlondorff ◽  
R. Neuwirth
Keyword(s):  
De Novo ◽  
Mesangial Cells ◽  
Biological Activities ◽  
Platelet Activating Factor ◽  
Calcium Ionophore ◽  
Initial Step ◽  
Renal Physiology ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells ◽  
Isolated Kidney

Platelet-activating factor (PAF) represents a group of phospholipids with the basic structure of 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine. A number of different cells are capable of producing PAF in response to various stimuli. The initial step of PAF formation is activation of phospholipase A2 in a calcium-dependent manner, yielding lyso-PAF. During this step arachidonic acid is also released and can be converted to its respective cyclooxygenase and lipoxygenase products. The lyso-PAF generated is then acetylated in position 2 of the glycerol backbone by a coenzyme A (CoA)-dependent acetyltransferase. An additional pathway may exist whereby PAF is generated de novo from 1-alkyl-2-acetyl-sn-glycerol by phosphocholine transferase. PAF inactivation in cells and blood is by specific acetylhydrolases. PAF exhibits a variety of biological activities including platelet and leukocyte aggregation and activation, increased vascular permeability, respiratory distress, decreased cardiac output, and hypotension. In the kidney PAF can produce decreases in blood flow, glomerular filtration, and fluid and electrolyte excretion. Intrarenal artery injection of PAF may also result in glomerular accumulation of platelets and leukocytes and mild proteinuria. PAF increases prostaglandin formation in the isolated kidney and in cultured glomerular mesangial cells. PAF also causes contraction of mesangial cells. Upon stimulation with calcium ionophore the isolated kidney, isolated glomeruli and medullary cells, and cultured mesangial cells are capable of producing PAF. The potential role for PAF in renal physiology and pathophysiology requires further investigation that may be complicated by 1) the multiple interactions of PAF, prostaglandins, and leukotrienes and 2) the autocoid nature of PAF, which may restrict its action to its site of generation.

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.

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