scholarly journals PKD2 is an essential ion channel subunit in the primary cilium of the renal collecting duct epithelium

2017 ◽  
Author(s):  
Xiaowen Liu ◽  
Thuy Vien ◽  
Jingjing Duan ◽  
Shu-Hsien Sheu ◽  
Paul G. DeCaen ◽  
...  
Keyword(s):  
Ion Channel ◽  
Primary Cilia ◽  
Collecting Duct ◽  
Primary Cultures ◽  
Hek 293 ◽  
Duct Epithelium ◽  
293 Cells ◽  
Novel Method ◽  
Autosomal Dominant Polycystic Kidney ◽  
Collecting Duct Epithelium

ABSTRACTMutations in either Pkd1 or Pkd2 result in Autosomal Dominant Polycystic Kidney Disease (ADPKD). Although PKD2 is proposed to be an ion channel subunit, recordings of PKD2 ion channels conflict in their properties. Using a new ADPKD mouse model, we observe primary cilia are abnormally long in cells associated with cysts. Using primary cultures of collecting duct epithelial cells, we show that PKD2, but not PKD1, is a required subunit for primary cilia ion channel. The ciliary PKD2 channel conducts potassium and sodium ions, but little calcium. We also demonstrate that PKD2 is not constitutively active in the plasma membrane, but PKD2 channels are functional in primary cilia and are sensitized by high cilioplasmic [Ca2+]. We introduce a novel method for measuring PKD2 channels heterologously expressed in primary cilia of HEK-293 cells, which will have utility characterizing Pkd2 variants that cause ADPKD in their native ciliary membrane.

scholarly journals Polycystin-2 is an essential ion channel subunit in the primary cilium of the renal collecting duct epithelium

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Xiaowen Liu ◽  
Thuy Vien ◽  
Jingjing Duan ◽  
Shu-Hsien Sheu ◽  
Paul G DeCaen ◽  
...  
Keyword(s):  
Ion Channel ◽  
Primary Cilium ◽  
Primary Cilia ◽  
Collecting Duct ◽  
Primary Cultures ◽  
Clear Understanding ◽  
Open Probability ◽  
Novel Method ◽  
Autosomal Dominant Polycystic Kidney ◽  
Collecting Duct Epithelium

Mutations in the polycystin genes, PKD1 or PKD2, results in Autosomal Dominant Polycystic Kidney Disease (ADPKD). Although a genetic basis of ADPKD is established, we lack a clear understanding of polycystin proteins’ functions as ion channels. This question remains unsolved largely because polycystins localize to the primary cilium – a tiny, antenna-like organelle. Using a new ADPKD mouse model, we observe primary cilia that are abnormally long in cells associated with cysts after conditional ablation of Pkd1 or Pkd2. Using primary cultures of collecting duct cells, we show that polycystin-2, but not polycystin-1, is a required subunit for the ion channel in the primary cilium. The polycystin-2 channel preferentially conducts K+ and Na+; intraciliary Ca2+, enhances its open probability. We introduce a novel method for measuring heterologous polycystin-2 channels in cilia, which will have utility in characterizing PKD2 variants that cause ADPKD.

scholarly journals Remodeling of the Fetal Collecting Duct Epithelium

2010 ◽  
Vol 176 (2) ◽  
pp. 630-637 ◽  
Author(s):  
Michael J. Hiatt ◽  
Larissa Ivanova ◽  
Nuria Toran ◽  
Alice F. Tarantal ◽  
Douglas G. Matsell
Keyword(s):  
Collecting Duct ◽  
Duct Epithelium ◽  
Collecting Duct Epithelium

scholarly journals Supercooling Agent Icilin Blocks a Warmth-Sensing Ion Channel TRPV3

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Muhammad Azhar Sherkheli ◽  
Guenter Gisselmann ◽  
Hanns Hatt
Keyword(s):  
Ion Channel ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Human Keratinocytes ◽  
Transient Receptor Potential Vanilloid ◽  
Neural Cells ◽  
Hek 293 ◽  
Low Concentrations ◽  
293 Cells ◽  
Transient Receptor

Transient receptor potential vanilloid subtype 3 (TRPV3) is a thermosensitive ion channel expressed in a variety of neural cells and in keratinocytes. It is activated by warmth (33–39°C), and its responsiveness is dramatically increased at nociceptive temperatures greater than 40°C. Monoterpenoids and 2-APB are chemical activators of TRPV3 channels. We found that Icilin, a known cooling substance and putative ligand of TRPM8, reversibly inhibits TRPV3 activity at nanomolar concentrations in expression systems likeXenopus laevesoocytes, HEK-293 cells, and in cultured human keratinocytes. Our data show that icilin's antagonistic effects for the warm-sensitive TRPV3 ion channel occurs at very low concentrations. Therefore, the cooling effect evoked by icilin may at least in part be due to TRPV3 inhibition in addition to TRPM8 potentiation. Blockade of TRPV3 activity by icilin at such low concentrations might have important implications for overall cooling sensations detected by keratinocytes and free nerve endings in skin. We hypothesize that blockage of TRPV3 might be a signal for cool-sensing systems (like TRPM8) to beat up the basal activity resulting in increased cold perception when warmth sensors (like TRPV3) are shut off.

scholarly journals Characterization of a murine renal distal convoluted tubule cell line for the study of transcellular calcium transport

2004 ◽  
Vol 286 (3) ◽  
pp. F483-F489 ◽  
Author(s):  
Robin J. W. Diepens ◽  
Els den Dekker ◽  
Marcelle Bens ◽  
A. Freek Weidema ◽  
Alain Vandewalle ◽  
...  
Keyword(s):  
Cell Line ◽  
Cell Model ◽  
Collecting Duct ◽  
Primary Cultures ◽  
Ruthenium Red ◽  
Distal Convoluted Tubule ◽  
Molecular Regulation ◽  
Hek 293 ◽  
Calbindin D

To unravel the molecular regulation of renal transcellular Ca2+ transport, a murine distal convoluted tubule (mpkDCT) cell line derived from distal convoluted tubules (DCT) microdissected from a SV-PK/Tag transgenic mouse was characterized. This cell line originated from DCT only, as mRNA encoding for the DCT marker thiazide-sensitive Na+/Cl- cotransporter was expressed, whereas mRNA encoding for the connecting tubule and collecting duct marker aquaporin-2 was not detected, as determined by reverse-transcriptase PCR. mpkDCT cells expressed mRNA encoding the Ca2+ channels TRPV5 and TRPV6 and other key players necessary for transcellular Ca2+ transport, i.e., calbindin-D9k, calbindin-D28k, plasma membrane Ca2+-ATPase isoform 1b, and Na+/Ca2+ exchanger 1. Primary cultures of DCT cells exhibited net transcellular Ca2+ transport of 0.4 ± 0.1 nmol·h-1·cm-2, whereas net transcellular Ca2+ transport across mpkDCT cells was significantly higher at 2.4 ± 0.4 nmol·h-1·cm-2. Transcellular Ca2+ transport across mpkDCT cells was completely inhibited by ruthenium red, an inhibitor of TRPV5 and TRPV6, but not by the voltage-operated Ca2+ channel inhibitors felodipine and verapamil. With the use of patch-clamp analysis, the IC50 of ruthenium red on Na+ currents was between the values measured for TRPV5- and TRPV6-expressing HEK 293 cells, suggesting that TRPV5 and/or TRPV6 is possibly active in mpkDCT cells. Forskolin in combination with IBMX, 1,25-dihydroxyvitamin D3, and 1-deamino-8-d-arginine vasopressin increased transcellular Ca2+ transport, whereas PMA and parathyroid hormone had no significant effect. In conclusion, the murine mpkDCT cell line provides a unique cell model in which to study the molecular regulation of transcellular Ca2+ transport in the kidney in vitro.

scholarly journals Ontogeny of Purinergic Receptor-Regulated Ca2+ Signaling in Mouse Cortical Collecting Duct Epithelium

2002 ◽  
Vol 12 (2-3) ◽  
pp. 75-82 ◽  
Author(s):  
Johannes Tschöp ◽  
Gerald Braun ◽  
Rene Borscheid ◽  
Michael Horster ◽  
Stephan Huber
Keyword(s):  
Purinergic Receptor ◽  
Collecting Duct ◽  
Cortical Collecting Duct ◽  
Duct Epithelium ◽  
Collecting Duct Epithelium

scholarly journals Phenotypic Transition of the Collecting Duct Epithelium in Congenital Urinary Tract Obstruction

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Peter Trnka ◽  
Michael J. Hiatt ◽  
Larissa Ivanova ◽  
Alice F. Tarantal ◽  
Douglas G. Matsell
Keyword(s):  
De Novo ◽  
Epithelial Mesenchymal Transition ◽  
Interstitial Fibrosis ◽  
Urinary Tract Obstruction ◽  
Collecting Duct ◽  
Obstructive Nephropathy ◽  
Primate Model ◽  
Mesenchymal Transition ◽  
Duct Epithelium ◽  
Collecting Duct Epithelium

Epithelial-mesenchymal transition (EMT) has emerged in recent years as an important process in the development of organ fibrosis in many human diseases. Our previous experience in a nonhuman primate model of obstructive nephropathy suggested that EMT of collecting duct epithelium contributes to the development of interstitial fibrosis. In this study we demonstrate for the first time in humans that obstructed fetal collecting duct epithelium undergoes transition to mesenchymal phenotype, characterized by decreased expression of epithelial markers, de novo expression of mesenchymal markers with subsequent loss of cell-cell interaction, disruption of the basement membrane, and increased deposition of extracellular matrix into the expanded interstitium of the obstructed kidney. The results of this study therefore support the previous findings from animal studies and suggest that EMT of the collecting duct epithelium might contribute to the development of interstitial fibrosis in human fetal obstructive nephropathy.

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