Screen-based identification and validation of four new ion channels as regulators of renal ciliogenesis

Slaats, Gisela G.; Wheway, Gabrielle; Foletto, Veronica; Szymańska, Katarzyna; Balkom, Bas W. M. van; Logister, Ive; Ouden, Krista den; Keijzer-Veen, Mandy G.; Lilien, Marc R.; Knoers, Nine V A M; Johnson, Colin A.; Giles, Rachel

doi:10.1242/jcs.176065

Cited by 17 publications

(14 citation statements)

References 42 publications

(50 reference statements)

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“…Although proteomic approaches are powerful, the lack of functional links between these candidate proteins and cilia dynamics has led to the development of targeted screens using reverse genetic approaches to specifically identify genes that modulate ciliogenesis. In addition to these global siRNA strategies (Wheway et al, 2015), key regulators of the cilium have been further identified using both screens aimed at targeting smaller subsets of therapeutically relevant genes across the genome (Kim et al, 2010; Lai et al, 2011a) and more specific screens like those evaluating the contributions of ion channels on ciliogenesis (Slaats et al, 2015). The strategy employed in our study differs from previous screens in its use of an unbiased approach, agnostic to the genes involved in ciliogenesis, to identify small-molecule compounds that can restore cilia in VHL -deficient cells.…”

Section: Discussionmentioning

confidence: 99%

Bexarotene – a novel modulator of AURKA and the primary cilium in VHL-deficient cells

Chowdhury

Powell²,

Stephan³

et al. 2018

Journal of Cell Science

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Loss of the gene von Hippel–Lindau (VHL) is associated with loss of primary cilia and is causally linked to elevated levels of Aurora kinase A (AURKA). We developed an image-based high-throughput screening (HTS) assay using a dual-labeling image analysis strategy that identifies both the cilium and the basal body. By using this strategy, we screened small-molecule compounds for the targeted rescue of cilia defects associated with VHL deficiency with high accuracy and reproducibility. Bexarotene was identified and validated as a positive regulator of the primary cilium. Importantly, the inability of an alternative retinoid X receptor (RXR) agonist to rescue ciliogenesis, in contrast to bexarotene, suggested that multiple bexarotene-driven mechanisms were responsible for the rescue. We found that bexarotene decreased AURKA expression in VHL-deficient cells, thereby restoring the ability of these cells to ciliate in the absence of VHL. Finally, bexarotene treatment reduced the propensity of subcutaneous lesions to develop into tumors in a mouse xenograft model of renal cell carcinoma (RCC), with a concomitant decrease in activated AURKA, highlighting the potential of bexarotene treatment as an intervention strategy in the clinic to manage renal cystogenesis associated with VHL deficiency and elevated AURKA expression.

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Section: Discussionmentioning

confidence: 99%

Bexarotene – a novel modulator of AURKA and the primary cilium in VHL-deficient cells

Chowdhury

Powell²,

Stephan³

et al. 2018

Journal of Cell Science

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“…Additionally, local changes in potential would influence the phospholipid composition of the membrane [56]; more specifically, it would reduce nanoclustering of PIP 2 , which influences the competence of the permeation barrier at the transition zone of the primary cilium [57]. Interestingly, a recent report noticed that another voltage-gated potassium channel (K V 7.1, KCNQ1) has the opposite effects in the mouse kidney [58], because its absence impairs ciliogenesis, indicating that K + permeability alone is not responsible for the effects we report here, and that the spatiotemporal control of expression and/or interactions with other proteins are required. Interactions of K V 10.1 with CTTN appear crucial for the regulation of ciliogenesis by the channel (Fig 9).…”

mentioning

confidence: 99%

Cyclic expression of the voltage‐gated potassium channel K_V10.1 promotes disassembly of the primary cilium

2016

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The primary cilium, critical for morphogenic and growth factor signaling, is assembled upon cell cycle exit, but the links between ciliogenesis and cell cycle progression are unclear. KV10.1 is a voltage‐gated potassium channel frequently overexpressed in tumors. We have previously reported that expression of KV10.1 is temporally restricted to a time period immediately prior to mitosis in healthy cells. Here, we provide microscopical and biochemical evidence that KV10.1 localizes to the centrosome and the primary cilium and promotes ciliary disassembly. Interference with KV10.1 ciliary localization abolishes not only the effects on ciliary disassembly, but also KV10.1‐induced tumor progression in vivo. Conversely, upon knockdown of KV10.1, ciliary disassembly is impaired, proliferation is delayed, and proliferating cells show prominent primary cilia. Thus, modulation of ciliogenesis by KV10.1 can explain the influence of KV10.1 expression on the proliferation of normal cells and is likely to be a major mechanism underlying its tumorigenic effects.

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“…A siRNA‐based reverse genetics screen identified KCNQ1 as a regulator of ciliogenesis and showed immunostaining of KCNQ1 at the base of primary cilia in a mouse cell line (Slaats et al . ). In a different study, a loss‐of‐function drug screen identified KCNQ1 as a regulatory candidate of L‐R asymmetry in Xenopus (Morokuma et al .…”

Section: Other Channels Implied In L‐r Axis Formationmentioning

confidence: 97%

New insights into ion channel‐dependent signalling during left‐right patterning

Tajhya

Delling

2019

The Journal of Physiology

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The left-right organizer (LRO) in the mouse consists of pit cells within the depression, located at the end of the developing notochord, also known as the embryonic node and crown cells lining the outer periphery of the node. Cilia on pit cells are posteriorly tilted, rotate clockwise and generate leftward fluid flow. Primary cilia on crown cells are required to interpret the directionality of fluid movement and initiate flow-dependent gene transcription. Crown cells express PC1-L1 and PC2, which may form a heteromeric polycystin channel complex on primary cilia. It is still only poorly understood how fluid flow activates the ciliary polycystin complex. Besides polycystin channels voltage gated channels like HCN4 and KCNQ1 have been implicated in establishing asymmetry. How this electrical network of ion channels initiates left-sided signalling cascades and differential gene expression is currently only poorly defined.Rajeev Tajhya received his PhD from Baylor College of Medicine. He worked on characterizing the role of potassium channels that affected myogenesis in patients with myotonic dystrophy type 1 and tested the stability and potency of a drug that is currently in a clinical trial for treatment of autoimmune diseases. He then worked as a postdoctoral fellow in the Delling lab to identify differences in the genetic map of the left and right sides of mouse embryonic node with a focus on ion channel genes and genes involved in congenital heart defects. Markus Delling obtained his PhD at the ZMNH at the University of Hamburg, Germany. He did his postdoctoral training with David Clapham at the Children's Hospital Boston, where he started working on ion channels in primary cilia. He now has his own lab at the University of California San Francisco where he continues to study the function of ion channels in primary cilia signalling. Abstract figure legendMotile cilia on pit cells (blue) generate a leftward directed flow within the LRO. Primary cilia on crown cells (brown) lining the outer perimeter of the node presumably function as flow detectors as they are required to initiate left-sided asymmetric gene expression (insert). The initial asymmetry generated within the LRO spreads out into the surrounding mesoderm (green) and thus defines the left side of the embryo. The polycystin members PC1-L1 and PC2 reside on primary cilia of crown cells and genetic evidence strongly suggests that this ion channel complex is required for flow-induced gene expression (insert). Yet the activation mechanism by which this ion channel complex is activated by flow on primary cilia still remains poorly understood. Besides ciliary polycystin channels other membrane localized voltage-gated channels (insert) have been implicated in establishing asymmetry, suggesting that they may function as signal amplifiers.

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Screen-based identification and validation of four new ion channels as regulators of renal ciliogenesis

Cited by 17 publications

References 42 publications

Bexarotene – a novel modulator of AURKA and the primary cilium in VHL-deficient cells

Bexarotene – a novel modulator of AURKA and the primary cilium in VHL-deficient cells

Cyclic expression of the voltage‐gated potassium channel K_V10.1 promotes disassembly of the primary cilium

New insights into ion channel‐dependent signalling during left‐right patterning

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Screen-based identification and validation of four new ion channels as regulators of renal ciliogenesis

Cited by 17 publications

References 42 publications

Bexarotene – a novel modulator of AURKA and the primary cilium in VHL-deficient cells

Bexarotene – a novel modulator of AURKA and the primary cilium in VHL-deficient cells

Cyclic expression of the voltage‐gated potassium channel KV10.1 promotes disassembly of the primary cilium

New insights into ion channel‐dependent signalling during left‐right patterning

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Cyclic expression of the voltage‐gated potassium channel K_V10.1 promotes disassembly of the primary cilium