More than colocalizing with polycystin-1, polycystin-l is in the centrosome

2006 ◽  
Vol 291 (2) ◽  
pp. F395-F406 ◽  
Author(s):  
Eva-Flore Bui-Xuan ◽  
Qiang Li ◽  
Xing-Zhen Chen ◽  
Catherine A. Boucher ◽  
Richard Sandford ◽  
...  
Keyword(s):  
Cell Cultures ◽  
Primary Cilia ◽  
Autosomal Dominant ◽  
Subcellular Fractionation ◽  
Cell Contact ◽  
Polycystic Kidney ◽  
Common Distribution ◽  
Confluent Cell ◽  
Autosomal Dominant Polycystic Kidney ◽  
Renal Cell Lines

Polycystin-1 and polycystin-2 are involved in autosomal dominant polycystic kidney disease by unknown mechanisms. These two proteins are located in primary cilia where they mediate mechanosensation, suggesting a link between cilia function and renal disease. In this study, we sought to characterize the subcellular localization of polycystin-l, a closely related member of polycystin-2, in epithelial renal cell lines. We have shown that endogenous polycystin-l subcellular distribution is different in proliferative and nonproliferative cultures. Polycystin-l is found mostly in the endoplasmic reticulum in subconfluent cell cultures, while in confluent cells it is redistributed to sites of cell-cell contact and to the primary cilium as is polycystin-1. Subcellular fractionation confirmed a common distribution of polycystin-l and polycystin-1 in the fractions corresponding to those containing the plasma membrane of postconfluent cells. Reciprocal coimmunoprecipitation experiments showed that polycystin-l was associated with polycystin-1 in a common complex in both subconfluent and confluent cell cultures. Interestingly, we also identified a novel site for a polycystin member (polycystin-l) in unciliated cells, the centrosome, which allowed us to reveal an involvement of polycystin-l in cell proliferation.

scholarly journals Molecular Pathways and Therapies in Autosomal-Dominant Polycystic Kidney Disease

Physiology ◽  
2015 ◽  
Vol 30 (3) ◽  
pp. 195-207 ◽  
Author(s):  
Takamitsu Saigusa ◽  
P. Darwin Bell
Keyword(s):  
Kidney Disease ◽  
Polycystic Kidney Disease ◽  
Primary Cilia ◽  
Autosomal Dominant ◽  
Molecular Pathways ◽  
Polycystic Kidney ◽  
Autosomal Dominant Polycystic Kidney ◽  
Multiple Cysts ◽  
Review Current

Autosomal-dominant polycystic kidney disease (ADPKD) is the most prevalent inherited renal disease, characterized by multiple cysts that can eventually lead to kidney failure. Studies investigating the role of primary cilia and polycystins have significantly advanced our understanding of the pathogenesis of PKD. This review will present clinical and basic aspects of ADPKD, review current concepts of PKD pathogenesis, evaluate potential therapeutic targets, and highlight challenges for future clinical studies.

scholarly journals Tubular STAT3 Limits Renal Inflammation in Autosomal Dominant Polycystic Kidney Disease

2020 ◽  
Vol 31 (5) ◽  
pp. 1035-1049 ◽  
Author(s):  
Amandine Viau ◽  
Maroua Baaziz ◽  
Amandine Aka ◽  
Manal Mazloum ◽  
Clément Nguyen ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Polycystic Kidney Disease ◽  
Primary Cilia ◽  
Autosomal Dominant ◽  
Polycystic Kidney ◽  
Polycystic Kidneys ◽  
Renal Inflammation ◽  
Tubular Cells ◽  
Autosomal Dominant Polycystic Kidney ◽  
Cyst Growth

BackgroundThe inactivation of the ciliary proteins polycystin 1 or polycystin 2 leads to autosomal dominant polycystic kidney disease (ADPKD). Although signaling by primary cilia and interstitial inflammation both play a critical role in the disease, the reciprocal interactions between immune and tubular cells are not well characterized. The transcription factor STAT3, a component of the cilia proteome that is involved in crosstalk between immune and nonimmune cells in various tissues, has been suggested as a factor fueling ADPKD progression.MethodTo explore how STAT3 intersects with cilia signaling, renal inflammation, and cyst growth, we used conditional murine models involving postdevelopmental ablation of Pkd1, Stat3, and cilia, as well as cultures of cilia-deficient or STAT3-deficient tubular cell lines.ResultsOur findings indicate that, although primary cilia directly modulate STAT3 activation in vitro, the bulk of STAT3 activation in polycystic kidneys occurs through an indirect mechanism in which primary cilia trigger macrophage recruitment to the kidney, which in turn promotes Stat3 activation. Surprisingly, although inactivating Stat3 in Pkd1-deficient tubules slightly reduced cyst burden, it resulted in a massive infiltration of the cystic kidneys by macrophages and T cells, precluding any improvement of kidney function. We also found that Stat3 inactivation led to increased expression of the inflammatory chemokines CCL5 and CXCL10 in polycystic kidneys and cultured tubular cells.ConclusionsSTAT3 appears to repress the expression of proinflammatory cytokines and restrict immune cell infiltration in ADPKD. Our findings suggest that STAT3 is not a critical driver of cyst growth in ADPKD but rather plays a major role in the crosstalk between immune and tubular cells that shapes disease expression.

scholarly journals Mispolarization of desmosomal proteins and altered intercellular adhesion in autosomal dominant polycystic kidney disease

2005 ◽  
Vol 288 (6) ◽  
pp. F1153-F1163 ◽  
Author(s):  
Melina Silberberg ◽  
Audra J. Charron ◽  
Robert Bacallao ◽  
Angela Wandinger-Ness
Keyword(s):  
Kidney Disease ◽  
Polycystic Kidney Disease ◽  
Laser Scanning ◽  
Autosomal Dominant ◽  
Cell Polarization ◽  
Cell Junctions ◽  
Cell Contact ◽  
Polycystic Kidney ◽  
Autosomal Dominant Polycystic Kidney ◽  
Cell Cell

Polycystin-1, the product of the major gene mutated in autosomal dominant polycystic kidney disease (ADPKD), has been shown to associate with multiple epithelial cell junctions. Our hypothesis is that polycystin-1 is an important protein for the initial establishment of cell-cell junctions and maturation of the cell and that polycystin-1 localization is dependent on the degree of cell polarization. Using laser-scanning confocal microscopy and two models of cell polarization, polycystin-1 and desmosomes were found to colocalize during the initial establishment of cell-cell contact when junctions were forming. However, colocalization was lost in confluent monolayers. Parallel morphological and biochemical evaluations revealed a profound mispolarization of desmosomal components to both the apical and basolateral domains in primary ADPKD cells and tissue. Studies of the intermediate filament network associated with desmosomes showed that there is a decrease in cytokeratin levels and an abnormal expression of the mesenchymal protein vimentin in the disease. Moreover, we show for the first time that the structural alterations seen in adherens and desmosomal junctions have a functional impact, leaving the ADPKD cells with weakened cell-cell adhesion. In conclusion, in this paper we show that polycystin-1 transiently colocalizes with desmosomes and that desmosomal proteins are mislocalized as a consequence of polycystin-1 mutation.

scholarly journals Tubular STAT3 limits renal inflammation in autosomal dominant polycystic kidney disease

2019 ◽  
Author(s):  
Amandine Viau ◽  
Maroua Baziz ◽  
Amandine Aka ◽  
Clément Nguyen ◽  
E. Wolfgang Kuehn ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Polycystic Kidney Disease ◽  
Primary Cilia ◽  
Autosomal Dominant ◽  
Polycystic Kidney ◽  
Polycystic Kidneys ◽  
Renal Inflammation ◽  
Tubular Cells ◽  
Autosomal Dominant Polycystic Kidney ◽  
Cyst Growth

ABSTRACTThe inactivation of the ciliary proteins polycystin 1 or 2 leads to autosomal dominant polycystic kidney disease (ADPKD), the leading genetic cause of chronic kidney disease. Both cilia signaling and interstitial inflammation play a critical role in the disease. Yet, the reciprocal interactions between immune and tubular cells are not well characterized. The transcription factor STAT3, which is suspected to fuel ADPKD progression, is involved in crosstalks between immune and non-immune cells in various tissues and is a component of the cilia proteome. Here, we explore how STAT3 intersects with cilia signaling, renal inflammation and cyst growth using conditional murine models of post-developmental Pkd1, Stat3 and cilia ablation. Our results indicate that, although primary cilia directly modulate STAT3 activation in vitro, the bulk of STAT3 activation in polycystic kidneys occurs through an indirect mechanism in which primary cilia trigger macrophage recruitment to the kidney, which in turn promotes STAT3 activation. Surprisingly, while disrupting Stat3 in Pkd1 deficient tubules slightly reduced cyst burden, it resulted in a massive infiltration of the cystic kidneys by macrophages and T cells, precluding any improvement of kidney function. Mechanistically, STAT3 represses the expression of the inflammatory chemokines CCL5 and CXCL10 in polycystic kidneys and cultured tubular cells. These results demonstrate that STAT3 is not a critical driver of cyst growth in ADPKD but plays a major role in the crosstalk between immune and tubular cells that shapes disease expression.

scholarly journals SUMOylation of the small GTPase ARL-13 promotes ciliary targeting of sensory receptors

2012 ◽  
Vol 199 (4) ◽  
pp. 589-598 ◽  
Author(s):  
Yujie Li ◽  
Qing Zhang ◽  
Qing Wei ◽  
Yuxia Zhang ◽  
Kun Ling ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Autosomal Dominant ◽  
Joubert Syndrome ◽  
Small Gtpase ◽  
Sensory Receptors ◽  
Polycystic Kidney ◽  
C Terminus ◽  
Autosomal Dominant Polycystic Kidney ◽  
Established Role ◽  
Sensory Functions

Primary cilia serve as cellular antenna for various sensory signaling pathways. However, how the sensory receptors are properly targeted to the ciliary surface remains poorly understood. Here, we show that UBC-9, the sole E2 small ubiquitin-like modifier (SUMO)-conjugating enzyme, physically interacts with and SUMOylates the C terminus of small GTPase ARL-13, the worm orthologue of ARL13B that mutated in ciliopathy Joubert syndrome. Mutations that totally abolish the SUMOylation of ARL-13 do not affect its established role in ciliogenesis, but fail to regulate the proper ciliary targeting of various sensory receptors and consequently compromise the corresponding sensory functions. Conversely, constitutively SUMOylated ARL-13 fully rescues all ciliary defects of arl-13–null animals. Furthermore, SUMOylation modification of human ARL13B is required for the ciliary entry of polycystin-2, the protein mutated in autosomal dominant polycystic kidney disease. Our data reveal a novel but conserved role for the SUMOylation modification of ciliary small GTPase ARL13B in specifically regulating the proper ciliary targeting of various sensory receptors.

scholarly journals Loss of polycystins suppresses deciliation via the activation of the centrosomal integrity pathway

2020 ◽  
Vol 3 (9) ◽  
pp. e202000750 ◽  
Author(s):  
Vasileios Gerakopoulos ◽  
Peter Ngo ◽  
Leonidas Tsiokas
Keyword(s):  
Cell Cycle ◽  
Kidney Disease ◽  
Signaling Pathways ◽  
Polycystic Kidney Disease ◽  
Primary Cilia ◽  
Autosomal Dominant ◽  
Polycystic Kidney ◽  
Cyclic Pattern ◽  
Autosomal Dominant Polycystic Kidney ◽  
Cystic Growth

The primary cilium is a microtubule-based, antenna-like organelle housing several signaling pathways. It follows a cyclic pattern of assembly and deciliation (disassembly and/or shedding), as cells exit and re-enter the cell cycle, respectively. In general, primary cilia loss leads to kidney cystogenesis. However, in animal models of autosomal dominant polycystic kidney disease, a major disease caused by mutations in the polycystin genes (Pkd1 or Pkd2), primary cilia ablation or acceleration of deciliation suppresses cystic growth, whereas deceleration of deciliation enhances cystogenesis. Here, we show that deciliation is delayed in the cystic epithelium of a mouse model of postnatal deletion of Pkd1 and in Pkd1- or Pkd2-null cells in culture. Mechanistic experiments show that PKD1 depletion activates the centrosomal integrity/mitotic surveillance pathway involving 53BP1, USP28, and p53 leading to a delay in deciliation. Reduced deciliation rate causes prolonged activation of cilia-based signaling pathways that could promote cystic growth. Our study links polycystins to cilia dynamics, identifies cellular deciliation downstream of the centrosomal integrity pathway, and helps explain pro-cystic effects of primary cilia in autosomal dominant polycystic kidney disease.

Inward calcium current through the polycystin-2-dependent channels of renal primary cilia

2021 ◽  
Author(s):  
Steven J. Kleene ◽  
Nancy K. Kleene
Keyword(s):  
Primary Cilium ◽  
Calcium Current ◽  
Primary Cilia ◽  
Autosomal Dominant ◽  
Collecting Duct ◽  
Polycystic Kidney ◽  
Renal Epithelial Cells ◽  
Medullary Collecting Duct ◽  
The Mean ◽  
Autosomal Dominant Polycystic Kidney

In 15% of cases, autosomal dominant polycystic kidney disease (ADPKD) arises from defects in polycystin-2 (PC2). PC2 is a member of the TRPP subfamily of cation-conducting channels and is expressed in the endoplasmic reticulum and primary cilium of renal epithelial cells. PC2 opposes a pro-cystogenic influence of the cilium, and it has been proposed that this beneficial effect is mediated in part by a flow of Ca2+ through PC2 channels into the primary cilium. However, previous efforts to determine the permeability of PC2 channels to Ca2+ have yielded widely varying results. Here we report the mean macroscopic Ca2+ influx through native PC2 channels in the primary cilia of mIMCD-3 cells, which are derived from murine inner medullary collecting duct. Under conditions designed to isolate inward Ca2+ currents, a small inward Ca2+ current was detected in cilia with active PC2 channels, but not in cilia lacking those channels. The current was activated by addition of 10 µM internal Ca2+, which is known to activate ciliary PC2 channels. It was blocked by 10 µM isosakuranetin, which blocks the same channels. On average, the current amplitude was −1.8 pA at −190 mV; its conductance from −50 to −200 mV averaged 20 pS. Thus the native PC2 channels of renal primary cilium are able to conduct a small but detectable Ca2+ influx under the conditions tested. The possible consequences of this influx are discussed.

scholarly journals Ca2+-Dependent Regulation by the Cyclic AMP Pathway of Primary Cilium Length in LLC-PK1 Renal Epithelial Cells

2020 ◽  
Author(s):  
Noelia Scarinci ◽  
Paula L. Perez ◽  
María del Rocío Cantero ◽  
Horacio F. Cantiello
Keyword(s):  
Kidney Disease ◽  
Epithelial Cells ◽  
Primary Cilium ◽  
Primary Cilia ◽  
Autosomal Dominant ◽  
Cyst Formation ◽  
Polycystic Kidney ◽  
Renal Epithelial Cells ◽  
Autosomal Dominant Polycystic Kidney ◽  
Cilium Length

AbstractThe primary cilium is a sensory organelle projecting from the apical surface of renal epithelial cells. Dysfunctional cilia have been linked to a number of genetic diseases known as ciliopathies, which include autosomal dominant polycystic kidney disease (ADPKD). Previous studies have determined that renal epithelial primary cilia express both the polycystin-2 (PC2, TRPP2) channel and the type-2 vasopressin receptor (V2R), coupled to local cAMP production. However, little is known as to how Ca2+ and cAMP signals lead to changes in the length of the primary cilium. Here, we explored how cAMP signals regulate the length of the primary cilium in wild type LLC-PK1 renal epithelial cells. Primary cilia length was determined by immunocytochemical labeling of the ciliary axoneme. Treatment of cells with the cAMP analog 8-Br-cAMP (1 mM) in normal external Ca2+ (1.2 mM) produced a 25.3% increase (p < 0.0001) in the length of the primary cilium, a phenomenon also observed in cells exposed to high external Ca2+ (6.2 mM). However, exposure of cells to vasopressin (AVP, 10 μM), which also increases cAMP in primary cilia of LLC-PK1 cells, mimicked the effect of 8-Br-cAMP in normal, but not in high Ca2+. Further, specific gene silencing of PC2 expression further increased primary cilium length after 8-Br-cAMP treatment, in normal, but not high Ca2+. The encompassed data indicate a crosstalk between the cAMP and Ca2+ signals to modulate the length of the primary cilium, in a phenomenon that implicates the expression of PC2.Significance StatementMorphological changes in primary cilia have been linked to genetic disorders, including autosomal dominant polycystic kidney disease (ADPKD), a major cause of kidney disease. Both cAMP and Ca2+ are universal second messengers that regulate polycystin-2 (PC2, TRPP2), a Ca2+ permeable non-selective cation channel implicated in ADPKD, and expressed in the primary cilium of renal epithelial cells. Despite current interest, little is known as to how second messenger systems and how aberrant regulation of PC2 may link primary cilium structure with cyst formation in ADPKD. Here we determined that both the cAMP analog 8-Br-cAMP and vasopressin increase the length of the primary cilium in renal epithelial cells. However, this phenomenon depends of external Ca2+ and PKD2 gene silencing. Proper cAMP signaling may be essential in the control of the primary cilium of renal epithelial cells, and the onset of cyst formation in ADPKD.

Sign in / Sign up

Export Citation Format

Share Document