scholarly journals Autosomal Recessive Polycystic Kidney Disease Epithelial Cell Model Reveals Multiple Basolateral Epidermal Growth Factor Receptor Sorting Pathways

2010 ◽  
Vol 21 (15) ◽  
pp. 2732-2745 ◽  
Author(s):  
Sean Ryan ◽  
Susamma Verghese ◽  
Nicholas L. Cianciola ◽  
Calvin U. Cotton ◽  
Cathleen R. Carlin

Sorting and maintenance of the EGF receptor on the basolateral surface of renal epithelial cells is perturbed in polycystic kidney disease and apical expression of receptors contributes to severity of disease. The goal of these studies was to understand the molecular basis for EGF receptor missorting using a well-established mouse model for the autosomal recessive form of the disease. We have discovered that multiple basolateral pathways mediate EGF receptor sorting in renal epithelial cells. The polycystic kidney disease allele in this model, Bicc1, interferes with one specific EGF receptor pathway without affecting overall cell polarity. Furthermore one of the pathways is regulated by a latent basolateral sorting signal that restores EGF receptor polarity in cystic renal epithelial cells via passage through a Rab11-positive subapical compartment. These studies give new insights to possible therapies to reconstitute EGF receptor polarity and function in order to curb disease progression. They also indicate for the first time that the Bicc1 gene that is defective in the mouse model used in these studies regulates cargo-specific protein sorting mediated by the epithelial cell specific clathrin adaptor AP-1B.

2008 ◽  
Vol 294 (4) ◽  
pp. F890-F899 ◽  
Author(s):  
Rajeev Rohatgi ◽  
Lorenzo Battini ◽  
Paul Kim ◽  
Sharon Israeli ◽  
Patricia D. Wilson ◽  
...  

Mutations of cilia-expressed proteins are associated with an attenuated shear-induced increase in intracellular Ca2+ concentration ([Ca2+]i) in renal epithelial cell lines derived from murine models of autosomal recessive polycystic kidney disease (ARPKD). We hypothesized that human ARPKD cyst-lining renal epithelial cells also exhibited dysregulated mechanosensation. To test this, conditionally immortalized cell lines derived from human fetal ARPKD cyst-lining (pool and clone 5E) cell lines with low levels of fibrocystin/polyductin expression and age-matched normal collecting tubule [human fetal collecting tubule (HFCT) pool and clone 2C] cell lines were grown in culture, loaded with a Ca2+ indicator dye, and subjected to laminar shear. Clonal cell lines were derived from single cells present in pools of cells from cyst-lining and collecting tubules, microdissected from human kidney. Resting and peak [Ca2+]i were similar between ARPKD 5E and pool, and HFCT 2C and pool; however, the flow-induced peak [Ca2+]i was greater in ARPKD 5E (700 ± 87 nM, n = 21) than in HFCT 2C (315 ± 58 nM, n = 12; P < 0.01) cells. ARPKD 5E cells treated with Gd3+, an inhibitor of nonselective cation channels, inhibited but did not abolish the shear-induced [Ca2+]i transient. Cilia were ∼20% shorter in ARPKD than HFCT cells, but no difference in ciliary localization or total cellular expression of polycystin-2, a mechanosenory Gd3+-sensitive cation channel, was detected between ARPKD and HFCT cells. The intracellular Ca2+ stores were similar between cells. In summary, human ARPKD cells exhibit an exaggerated Gd3+-sensitive mechano-induced Ca2+ response compared with controls; whether this represents dysregulated polycystin-2 activity in ARPKD cells remains to be explored.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hao Ding ◽  
Linda Xiaoyan Li ◽  
Peter C. Harris ◽  
Junwei Yang ◽  
Xiaogang Li

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.


2011 ◽  
Vol 300 (2) ◽  
pp. F511-F520 ◽  
Author(s):  
Hiroko Togawa ◽  
Koichi Nakanishi ◽  
Hironobu Mukaiyama ◽  
Taketsugu Hama ◽  
Yuko Shima ◽  
...  

In polycystic kidney disease (PKD), cyst lining cells show polarity abnormalities. Recent studies have demonstrated loss of cell contact in cyst cells, suggesting induction of epithelial-to-mesenchymal transition (EMT). Recently, EMT has been implicated in the pathogenesis of PKD. To explore further evidence of EMT in PKD, we examined age- and segment-specific expression of adhesion molecules and mesenchymal markers in PCK rats, an orthologous model of human autosomal-recessive PKD. Kidneys from 5 male PCK and 5 control rats each at 0 days, 1, 3, 10, and 14 wk, and 4 mo of age were serially sectioned and stained with segment-specific markers and antibodies against E-cadherin, Snail1, β-catenin, and N-cadherin. mRNAs for E-cadherin and Snail1 were quantified by real-time PCR. Vimentin, fibronectin, and α-smooth muscle actin (α-SMA) expressions were assessed as mesenchymal markers. E-cadherin expression pattern was correlated with the disease pathology in that tubule segments showing the highest expression in control had much severer cyst formation in PCK rats. In PCK rats, E-cadherin and β-catenin in cystic tubules was attenuated and localized to lateral areas of cell-cell contact, whereas nuclear expression of Snail1 increased in parallel with cyst enlargement. Some epithelial cells in large cysts derived from these segments, especially in adjacent fibrotic areas, showed positive immunoreactivity for vimentin and fibronectin. In conclusion, these findings suggest that epithelial cells in cysts acquire mesenchymal features in response to cyst enlargement and participate in progressive renal fibrosis. Our study clarified the nephron segment-specific cyst profile related to EMT in PCK rats. EMT may play a key role in polycystic kidney disease.


2008 ◽  
Vol 19 (10) ◽  
pp. 1929-1939 ◽  
Author(s):  
Frank Park ◽  
William E. Sweeney ◽  
Guangfu Jia ◽  
Richard J. Roman ◽  
Ellis D. Avner

2007 ◽  
Vol 72 (3) ◽  
pp. 328-336 ◽  
Author(s):  
J.R. Woollard ◽  
R. Punyashtiti ◽  
S. Richardson ◽  
T.V. Masyuk ◽  
S. Whelan ◽  
...  

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Dorien Van Giel ◽  
Jean-Paul Decuypere ◽  
Djalila Mekahli ◽  
Rudi Vennekens

Abstract Background and Aims Autosomal Dominant Polycystic Kidney Disease (ADPKD) is an inheritable kidney disease characterized by the development of fluid-filled cysts in all nephron segments, leading to loss of renal function. Mutations in PKD1 or PKD2, which encode polycystin-1 and polycystin-2, are the most common cause of ADPKD. The molecular mechanisms underlying cystogenesis are poorly characterized but it is postulated that disturbed calcium homeostasis is a primary event in cystogenesis. The precise molecular players that cause this disturbance are still a poorly explored area, especially in relevant human cell types. We therefore aim to characterize the profile of calcium-coupled receptors and channels in a human renal epithelial cell model, to identify which receptors and channels are present and whether their function is affected in ADPKD. Method Human urine-derived conditionally immortalized proximal tubule epithelial cells (ciPTECs) of ADPKD patients and healthy controls were screened for calcium-coupled GPCRs, using a GPCR agonist library on Fura-2 loaded cell populations seeded in 96-well format using the Flexstation3 (Molecular Devices). Validation of specific hits was done using single-cell measurements with a fluorescence microscope and built-in perfusion system. The expression of TRP channels and STIM/Orai proteins was determined via qPCR. Results From a library of 418 GPCR agonists a selective amount of calcium-coupled GPCRs was found functionally active in ciPTECs. ciPTECs from both healthy controls and ADPKD patients were found to functionally express purinergic -, histamine -, serotonin and dopamine receptors. Through qPCR we found expression of various TRP channels, including TRPML1, TRPC1/3, TRPM3/4/7, TRPV4 and TRPA1, as well as high expression of STIM1/2 and Orai1/2/3. Conclusion We describe the first thorough characterization of molecular players involved in calcium signalling mechanisms in human renal epithelial cells, including the profile of calcium-coupled GPCRs and the expression of TRP channels and STIM/Orai proteins, of further interest to investigate disturbed calcium dynamics in ADPKD.


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