Alpha-1-Adrenoceptor-Mediated Phosphoinositide Hydrolysis in Renal Epithelial Cells

AbstractActivation of the apoptotic pathway is a major cause of progressive loss of function in chronic diseases such as neurodegenerative and diabetic kidney diseases. There is an unmet need for an anti-apoptotic drug that acts in the early stage of the apoptotic process. The multifunctional protein Na+,K+-ATPase has, in addition to its role as a transporter, a signaling function that is activated by its ligand, the cardiotonic steroid ouabain. Several lines of evidence suggest that sub-saturating concentrations of ouabain protect against apoptosis of renal epithelial cells, a common complication and major cause of death in diabetic patients. Here, we induced apoptosis in primary rat renal epithelial cells by exposing them to an elevated glucose concentration (20 mM) and visualized the early steps in the apoptotic process using super-resolution microscopy. Treatment with 10 nM ouabain interfered with the onset of the apoptotic process by inhibiting the activation of the BH3-only protein Bad and its translocation to mitochondria. This occurred before the pro-apoptotic protein Bax had been recruited to mitochondria. Two ouabain regulated and Akt activating Ca2+/calmodulin-dependent kinases were found to play an essential role in the ouabain anti-apoptotic effect. Our results set the stage for further exploration of ouabain as an anti-apoptotic drug in diabetic kidney disease as well as in other chronic diseases associated with excessive apoptosis.

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Three-dimensional Growth of Renal Epithelial Cells in Vitro: A Tool in Toxicity Testing

Alternatives to Laboratory Animals ◽

10.1177/026119299302100212 ◽

1993 ◽

Vol 21 (2) ◽

pp. 191-195 ◽

Cited By ~ 1

Author(s):

Knut-Jan Andersen ◽

Erik Ilsø Christensen ◽

Hogne Vik

Keyword(s):

Epithelial Cells ◽

Three Dimensional ◽

Toxicity Testing ◽

Renal Tissue ◽

Epithelial Cell Line ◽

Multicellular Spheroids ◽

Renal Epithelial Cell ◽

Renal Epithelial Cells

The tissue culture of multicellular spheroids from the renal epithelial cell line LLC-PK1 (proximal tubule) is described. This represents a biological system of intermediate complexity between renal tissue in vivo and simple monolayer cultures. The multicellular structures, which show many similarities to kidney tubules in vivo, including a vectorial water transport, should prove useful for studying the potential nephrotoxicity of drugs and chemicals in vitro. In addition, the propagation of renal epithelial cells as multicellular spheroids in serum-free culture may provide information on the release of specific biological parameters, which may be suppressed or masked in serum-supplemented media.

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Effect of pH and bicarbonate on phosphoenolpyruvate carboxykinase and glutaminase mRNA levels in cultured renal epithelial cells

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)92832-2 ◽

1991 ◽

Vol 266 (15) ◽

pp. 9397-9402 ◽

Cited By ~ 2

Author(s):

S. Kaiser ◽

N.P. Curthoys

Keyword(s):

Epithelial Cells ◽

Phosphoenolpyruvate Carboxykinase ◽

Mrna Levels ◽

Effect Of Ph ◽

Renal Epithelial Cells

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Extracellular vesicles and exosomes generated from cystic renal epithelial cells promote cyst growth in autosomal dominant polycystic kidney disease

Nature Communications ◽

10.1038/s41467-021-24799-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Hao Ding ◽

Linda Xiaoyan Li ◽

Peter C. Harris ◽

Junwei Yang ◽

Xiaogang Li

Keyword(s):

Kidney Disease ◽

Epithelial Cells ◽

Polycystic Kidney Disease ◽

Extracellular Vesicles ◽

Autosomal Dominant ◽

Therapeutic Potential ◽

Polycystic Kidney ◽

Renal Epithelial Cells ◽

Autosomal Dominant Polycystic Kidney ◽

Cyst Growth

AbstractAutosomal dominant polycystic kidney disease (ADPKD) is caused by germline mutations of PKD1 or PKD2 on one allele and a somatic mutation inactivating the remaining normal allele. However, if and how null ADPKD gene renal epithelial cells affect the biology and function of neighboring cells, including heterozygous renal epithelial cells, fibroblasts and macrophages during cyst initiation and expansion remains unknown. Here we address this question with a “cystic extracellular vesicles/exosomes theory”. We show that cystic cell derived extracellular vesicles and urinary exosomes derived from ADPKD patients promote cyst growth in Pkd1 mutant kidneys and in 3D cultures. This is achieved by: 1) downregulation of Pkd1 gene expression and upregulation of specific miRNAs, resulting in the activation of PKD associated signaling pathways in recipient renal epithelial cells and tissues; 2) the activation of fibroblasts; and 3) the induction of cytokine expression and the recruitment of macrophages to increase renal inflammation in cystic kidneys. Inhibition of exosome biogenesis/release with GW4869 significantly delays cyst growth in aggressive and milder ADPKD mouse models, suggesting that targeting exosome secretion has therapeutic potential for ADPKD.

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