MO007ANALYSIS OF CALCIUM SIGNALING IN AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE (ADPKD)

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Dorien Van Giel ◽  
Jean-Paul Decuypere ◽  
Djalila Mekahli ◽  
Rudi Vennekens
Keyword(s):  
Kidney Disease ◽  
Epithelial Cells ◽  
Polycystic Kidney Disease ◽  
Molecular Mechanisms ◽  
Autosomal Dominant ◽  
Trp Channels ◽  
Cell Model ◽  
Healthy Controls ◽  
Polycystic Kidney ◽  
Autosomal Dominant Polycystic Kidney

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.

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

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.

Activation of NRF2 ameliorates oxidative stress and cystogenesis in autosomal dominant polycystic kidney disease

2020 ◽  
Vol 12 (554) ◽  
pp. eaba3613 ◽  
Author(s):  
Yi Lu ◽  
Yongzhan Sun ◽  
Zhiheng Liu ◽  
Yumei Lu ◽  
Xu Zhu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Kidney Disease ◽  
Polycystic Kidney Disease ◽  
Molecular Mechanisms ◽  
Autosomal Dominant ◽  
Redox Homeostasis ◽  
Separation Mechanism ◽  
Related Factor ◽  
Polycystic Kidney ◽  
Autosomal Dominant Polycystic Kidney

Oxidative stress is emerging as a crucial contributor to the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD), but the molecular mechanisms underlying the disturbed redox homeostasis in cystic cells remain elusive. Here, we identified the impaired activity of the NRF2 (nuclear factor erythroid 2–related factor 2) antioxidant pathway as a driver of oxidative damage and ADPKD progression. Using a quantitative proteomic approach, together with biochemical analyses, we found that increased degradation of NRF2 protein suppressed the NRF2 antioxidant pathway in ADPKD mouse kidneys. In a cohort of patients with ADPKD, reactive oxygen species (ROS) frequently accumulated, and their production correlated negatively with NRF2 abundance and positively with disease severity. In an orthologous ADPKD mouse model, genetic deletion of Nrf2 further increased ROS generation and promoted cyst growth, whereas pharmacological induction of NRF2 reduced ROS production and slowed cystogenesis and disease progression. Mechanistically, pharmacological induction of NRF2 remodeled enhancer landscapes and activated NRF2-bound enhancer-associated genes in ADPKD cells. The activation domain of NRF2 formed phase-separated condensates with MEDIATOR complex subunit MED16 in vitro, and optimal Mediator recruitment to genomic loci depended on NRF2 in vivo. Together, these findings indicate that NRF2 remodels enhancer landscapes and activates its target genes through a phase separation mechanism and that activation of NRF2 represents a promising strategy for restoring redox homeostasis and combatting ADPKD.

scholarly journals Insights into cellular and molecular basis for urinary tract infection in autosomal-dominant polycystic kidney disease

2017 ◽  
Vol 313 (5) ◽  
pp. F1077-F1083 ◽  
Author(s):  
Chao Gao ◽  
Long Zhang ◽  
Ye Zhang ◽  
Darren P. Wallace ◽  
Reynold I. Lopez-Soler ◽  
...  
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Kidney Disease ◽  
Tract Infection ◽  
Polycystic Kidney Disease ◽  
Molecular Mechanisms ◽  
Autosomal Dominant ◽  
Immune Defense ◽  
Polycystic Kidney ◽  
Autosomal Dominant Polycystic Kidney

Urinary tract infection (UTI) is a broad term referring to an infection of the kidneys, ureters, bladder, and/or urethra. Because of its prevalence, frequent recurrence, and rising resistance to antibiotics, UTI has become a challenge in clinical practice. Autosomal-dominant polycystic kidney disease (ADPKD) is the most common monogenic disorder of the kidney and is characterized by the growth of fluid-filled cysts in both kidneys. Progressive cystic enlargement, inflammation, and interstitial fibrosis result in nephron loss with subsequent decline in kidney function. ADPKD patients frequently develop UTI; however, the cellular and molecular mechanisms responsible for the high UTI incidence in ADPKD patients remain virtually unaddressed. Emerging evidence suggests that α-intercalated cells (α-ICs) of the collecting ducts function in the innate immune defense against UTI. α-ICs inhibit bacterial growth by acidifying urine and secreting neutrophil gelatinase-associated lipocalin (NGAL) that chelates siderophore-containing iron. It is necessary to determine, therefore, if ADPKD patients with recurrent UTI have a reduced number and/or impaired function of α-ICs. Identification of the underlying cellular and molecular mechanisms may lead to the development of novel strategies to reduce UTI in ADPKD.

scholarly journals Ouabain activates the Na-K-ATPase signalosome to induce autosomal dominant polycystic kidney disease cell proliferation

2011 ◽  
Vol 301 (4) ◽  
pp. F897-F906 ◽  
Author(s):  
Anh-Nguyet T. Nguyen ◽  
Kyle Jansson ◽  
Gladis Sánchez ◽  
Madhulika Sharma ◽  
Gail A. Reif ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Kidney Disease ◽  
Epithelial Cells ◽  
Polycystic Kidney Disease ◽  
Kinase Inhibitors ◽  
Autosomal Dominant ◽  
Renal Cysts ◽  
Cell Nuclei ◽  
Polycystic Kidney ◽  
Autosomal Dominant Polycystic Kidney

The Na-K-ATPase is part of a cell signaling complex, the Na-K-ATPase signalosome, which upon activation by the hormone ouabain regulates the function of different cell types. We previously showed that ouabain induces proliferation of epithelial cells derived from renal cysts of patients with autosomal dominant polycystic kidney disease (ADPKD cells). Here, we investigated the signaling pathways responsible for mediating the effects of ouabain in these cells. Incubation of ADPKD cells with ouabain, in concentrations similar to those found in blood, stimulated phosphorylation of the epidermal growth factor receptor (EGFR) and promoted its association to the Na-K-ATPase. In addition, ouabain activated the kinase Src, but not the related kinase Fyn. Tyrphostin AG1478 and PP2, inhibitors of EGFR and Src, respectively, blocked ouabain-dependent ADPKD cell proliferation. Treatment of ADPKD cells with ouabain also caused phosphorylation of the caveolar protein caveolin-1, and disruption of cell caveolae with methyl-β-cyclodextrin prevented Na-K-ATPase-EGFR interaction and ouabain-induced proliferation of the cells. Downstream effects of ouabain in ADPKD cells included activation of B-Raf and MEK and phosphorylation of the extracellular regulated kinase ERK, which translocated into the ADPKD cell nuclei. Finally, ouabain reduced expression of the cyclin-dependent kinase inhibitors p21 and p27, which are suppressors of cell proliferation. Different from ADPKD cells, ouabain showed no significant effect on B-Raf, p21, and p27 in normal human kidney epithelial cells. Altogether, these results identify intracellular pathways of ouabain-dependent Na-K-ATPase-mediated signaling in ADPKD cells, including EGFR-Src-B-Raf-MEK/ERK, and establish novel mechanisms involved in ADPKD cell proliferation.

scholarly journals Synergistic Antiproliferative Effects of All-Trans Retinoic Acid and Paclitaxel on Autosomal Dominant Polycystic Kidney Disease Epithelial Cells

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Que Thanh Thanh Nguyen ◽  
Thi Xoan Hoang ◽  
Hyunjin Ryu ◽  
Kook-Hwan Oh ◽  
Jae Young Kim
Keyword(s):  
Retinoic Acid ◽  
Kidney Disease ◽  
Epithelial Cells ◽  
Polycystic Kidney Disease ◽  
Autosomal Dominant ◽  
Polycystic Kidney ◽  
Antiproliferative Effects ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Autosomal Dominant Polycystic Kidney

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by uncontrollable epithelial cell growth, cyst formation, and kidney malfunction. In the present study, we investigated the antiproliferative effects of the treatment with the combination of paclitaxel (PAC) and all-trans retinoic acid (ATRA) on ADPKD epithelial cells. Our results show that the combined treatment with 1 nM PAC and 10 nM ATRA significantly suppressed ADPKD cell proliferation (20%), while the treatment with ATRA or PAC alone had no such effect. Treatment with PAC and ATRA induced cell cycle arrest at the G2/M phase and apoptosis by upregulating p53 and caspase-8 expression and increased the intracellular calcium (Ca2+) level possibly by enhancing Ca2+ uptake via plasma membrane channels. In addition, this treatment suppressed extracellular signal-regulated kinase signaling possibly through mitogen-activated protein kinase phosphatase-1 activation. Thus, the combination of PAC and ATRA can be explored as a potential treatment regimen for ADPKD.

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