scholarly journals Targeting an anchored phosphatase-deacetylase unit restores renal ciliary homeostasis

2021 ◽  
Author(s):  
Janani Gopalan ◽  
Mitch Omar ◽  
Ankita Roy ◽  
Nelly M. Cruz ◽  
Jerome Falcone ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Genetic Disorder ◽  
Actin Dynamics ◽  
Histone Deacetylase 6 ◽  
Collecting Ducts ◽  
Cytoskeletal Dynamics ◽  
Anchoring Protein ◽  
Autosomal Dominant Polycystic Kidney ◽  
On Chip ◽  
The Stability

AbstractPathophysiological defects in water homeostasis can lead to renal failure. Autosomal dominant polycystic kidney disease (ADPKD) is a common genetic disorder associated with abnormal cytoskeletal dynamics in the kidney collecting ducts and perturbed calcium and cAMP signaling in the ciliary compartment. We show that collecting ducts in mice lacking the A-Kinase anchoring protein AKAP220 exhibit enhanced development of primary cilia. Mechanistic studies reveal that AKAP220-associated protein phosphatase 1 (PP1) mediates this phenotype by promoting changes in the stability of histone deacetylase 6 (HDAC6) with concomitant defects in actin dynamics. This proceeds through a previously unrecognized adaptor function for PP1 as all ciliogenesis and cytoskeletal phenotypes are recapitulated in mIMCD3 knock-in cells expressing a phosphatase-targeting defective AKAP220-ΔPP1 mutant. Pharmacological blocking of local HDAC6 activity alters cilia development and reduces cystogenesis in kidney-on-chip and organoid models of ADPKD. These findings identify the AKAP220-PPI-HDAC6 pathway as a key effector in primary cilia development.

scholarly journals Targeting an anchored phosphatase-deacetylase unit restores renal ciliary homeostasis

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Janani Gopalan ◽  
Mitchell H Omar ◽  
Ankita Roy ◽  
Nelly M Cruz ◽  
Jerome Falcone ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Genetic Disorders ◽  
Chronic Kidney Failure ◽  
Actin Dynamics ◽  
Histone Deacetylase 6 ◽  
Collecting Ducts ◽  
Cytoskeletal Dynamics ◽  
Anchoring Protein ◽  
On Chip ◽  
The Stability

Pathophysiological defects in water homeostasis can lead to renal failure. Likewise, common genetic disorders associated with abnormal cytoskeletal dynamics in the kidney collecting ducts and perturbed calcium and cAMP signaling in the ciliary compartment contribute to chronic kidney failure. We show that collecting ducts in mice lacking the A-Kinase anchoring protein AKAP220 exhibit enhanced development of primary cilia. Mechanistic studies reveal that AKAP220-associated protein phosphatase 1 (PP1) mediates this phenotype by promoting changes in the stability of histone deacetylase 6 (HDAC6) with concomitant defects in actin dynamics. This proceeds through a previously unrecognized adaptor function for PP1 as all ciliogenesis and cytoskeletal phenotypes are recapitulated in mIMCD3 knock-in cells expressing a phosphatase-targeting defective AKAP220-ΔPP1 mutant. Pharmacological blocking of local HDAC6 activity alters cilia development and reduces cystogenesis in kidney-on-chip and organoid models. These findings identify the AKAP220-PPI-HDAC6 pathway as a key effector in primary cilia development.

Nonmuscle myosin IIA and IIB differently suppress microtubule growth to stabilize cell morphology

2019 ◽  
Vol 167 (1) ◽  
pp. 25-39 ◽  
Author(s):  
Yuta Sato ◽  
Keiju Kamijo ◽  
Motosuke Tsutsumi ◽  
Yota Murakami ◽  
Masayuki Takahashi
Keyword(s):  
Cell Morphology ◽  
Control Cell ◽  
Growth Dynamics ◽  
Actin Dynamics ◽  
Nonmuscle Myosin ◽  
Cellular Processes ◽  
Nonmuscle Myosin Ii ◽  
Cytoskeletal Dynamics ◽  
Dependent Inhibition ◽  
The Stability

Abstract Precise regulation of cytoskeletal dynamics is important in many fundamental cellular processes such as cell shape determination. Actin and microtubule (MT) cytoskeletons mutually regulate their stability and dynamics. Nonmuscle myosin II (NMII) is a candidate protein that mediates the actin–MT crosstalk. NMII regulates the stability and dynamics of actin filaments to control cell morphology. Additionally, previous reports suggest that NMII-dependent cellular contractility regulates MT dynamics, and MTs also control cell morphology; however, the detailed mechanism whereby NMII regulates MT dynamics and the relationship among actin dynamics, MT dynamics and cell morphology remain unclear. The present study explores the roles of two well-characterized NMII isoforms, NMIIA and NMIIB, on the regulation of MT growth dynamics and cell morphology. We performed RNAi and drug experiments and demonstrated the NMII isoform-specific mechanisms—NMIIA-dependent cellular contractility upregulates the expression of some mammalian diaphanous-related formin (mDia) proteins that suppress MT dynamics; NMIIB-dependent inhibition of actin depolymerization suppresses MT growth independently of cellular contractility. The depletion of either NMIIA or NMIIB resulted in the increase in cellular morphological dynamicity, which was alleviated by the perturbation of MT dynamics. Thus, the NMII-dependent control of cell morphology significantly relies on MT dynamics.

scholarly journals BBSome regulation of LITE-1 receptor in a cilium-independent manner in C. elegans

2020 ◽  
Author(s):  
Xinxing Zhang ◽  
Jinzhi Liu ◽  
Jianfeng Liu ◽  
X.Z. Shawn Xu
Keyword(s):  
Primary Cilia ◽  
Genetic Disorder ◽  
Light Sensitivity ◽  
Dependent Manner ◽  
Independent Manner ◽  
C Elegans ◽  
Light Sensing ◽  
Ciliary Protein ◽  
The Stability ◽  
And Function

AbstractBardet-Biedl Syndrome (BBS) is a genetic disorder affecting primary cilia. BBSome, a protein complex composed of eight BBS proteins, regulates the structure and function of cilia in diverse organisms, and its malfunction causes BBS in humans. Here, we report a new function of BBSome in C. elegans. In a forward genetic screen for genes regulating the light sensitivity of the ciliated ASH sensory neurons, we isolated bbs mutants, indicating that BBSome regulates ASH photosensitivity. Surprisingly, cilia are not required for ASH neurons to sense light, suggesting that BBSome regulates ASH photosensitivity independently of cilia. Interestingly, the light-sensing receptor LITE-1, which mediates photosensation, is a non-ciliary protein in ASH neurons. LITE-1 in ASH neurons becomes unstable in bbs mutants in an age-dependent manner, indicating that BBSome regulates the stability of LITE-1 in these neurons. These results identify a cilium-independent function of BBSome in regulating a non-ciliary protein in ciliated cells.

Detection of PKD1 and PKD2 Somatic Variants in Autosomal Dominant Polycystic Kidney Cyst Epithelial Cells by Whole-Genome Sequencing

2021 ◽  
pp. ASN.2021050690
Author(s):  
Zhengmao Zhang ◽  
Hanwen Bai ◽  
Jon Blumenfeld ◽  
Andrew Ramnauth ◽  
Irina Barash ◽  
...  
Keyword(s):  
Autosomal Dominant ◽  
Genetic Disorder ◽  
Fragile Sites ◽  
Whole Genome ◽  
Sequencing Analysis ◽  
Polycystic Kidney ◽  
Second Hit ◽  
Kidney Cyst ◽  
Kidney Cysts ◽  
Autosomal Dominant Polycystic Kidney

Background: Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by the development of multiple cysts in the kidneys. It is often caused by pathogenic mutations in PKD1 and PKD2 genes that encode polycystin proteins. Although the molecular mechanisms for cystogenesis are not established, concurrent inactivating germline and somatic mutations in PKD1 and PKD2 have been previously observed in renal tubular epithelium (RTE). Methods: To further investigate the cellular recessive mechanism of cystogenesis in RTE, we conducted whole-genome DNA sequencing analysis to identify germline variants and somatic alterations in RTE of 90 unique kidney cysts obtained during nephrectomy from 24 unrelated participants. Results: Kidney cysts were overall genomically stable, with low burdens of somatic short mutations or large-scale structural alterations. Pathogenic somatic "second hit" alterations disrupting PKD1 or PKD2 were identified in 93% of the cysts. Of these, 77% of cysts acquired short mutations in PKD1 or PKD2; specifically, 60% resulted in protein truncations (nonsense, frameshift, or splice site) and 16.7% caused non-truncating mutations (missense, in-frame insertions, or deletions). Another ~18% of cysts acquired somatic chromosomal loss of heterozygosity (LOH) events encompassing PKD1 or PKD2 ranging from 2.6 to 81.3 Mb. 14.4% of these cysts harbored copy number neutral LOH events, while the other 3.3% had hemizygous chromosomal deletions. LOH events frequently occurred at chromosomal fragile sites, or in regions comprising chromosome microdeletion diseases/syndromes. Almost all somatic "second hit" alterations occurred at the same germline mutated PKD1/2 gene. Conclusions: These findings further support a cellular recessive mechanism for cystogenesis in ADPKD primarily caused by inactivating germline and somatic variants of PKD1 or PKD2 genes in kidney cyst epithelium.

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 Integrin-β1 is required for the renal cystogenesis caused by ciliary defects

2020 ◽  
Vol 318 (5) ◽  
pp. F1306-F1312
Author(s):  
Miran Yoo ◽  
Laura M. C. Barisoni ◽  
Kyung Lee ◽  
G. Luca Gusella
Keyword(s):  
Inflammatory Infiltrate ◽  
Primary Cilia ◽  
Genetic Model ◽  
Renal Cysts ◽  
Intraflagellar Transport ◽  
The Other ◽  
Integrin Β1 ◽  
Principal Cells ◽  
Other Hand ◽  
Collecting Ducts

Defects in the function of primary cilia are commonly associated with the development of renal cysts. On the other hand, the intact cilium appears to contribute a cystogenic signal whose effectors remain unclear. As integrin-β1 is required for the cystogenesis caused by the deletion of the polycystin 1 gene, we asked whether it would be similarly important in the cystogenetic process caused by other ciliary defects. We addressed this question by investigating the effect of integrin-β1 deletion in a ciliopathy genetic model in which the Ift88 gene, a component of complex B of intraflagellar transport that is required for the proper assembly of cilia, is specifically ablated in principal cells of the collecting ducts. We showed that the renal cystogenesis caused by loss of Ift88 is prevented when integrin-β1 is simultaneously depleted. In parallel, pathogenetic manifestations of the disease, such as increased inflammatory infiltrate and fibrosis, were also significantly reduced. Overall, our data indicate that integrin-β1 is also required for the renal cystogenesis caused by ciliary defects and point to integrin-β1-controlled pathways as common drivers of the disease and as possible targets to interfere with the cystogenesis caused by ciliary defects.

scholarly journals Surface-Tension-Confined Channel with Biomimetic Microstructures for Unidirectional Liquid Spreading

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 978
Author(s):  
Yi Zhang ◽  
Yang Gan ◽  
Liwen Zhang ◽  
Deyuan Zhang ◽  
Huawei Chen
Keyword(s):  
Surface Tension ◽  
Underlying Mechanism ◽  
Structural Features ◽  
Liquid Motion ◽  
Water Separation ◽  
Lab On Chip ◽  
Liquid Spreading ◽  
Oil Water Separation ◽  
On Chip ◽  
The Stability

Unidirectional liquid spreading without energy input is of significant interest for the broad applications in diverse fields such as water harvesting, drop transfer, oil–water separation and microfluidic devices. However, the controllability of liquid motion and the simplification of manufacturing process remain challenges. Inspired by the peristome of Nepenthes alata, a surface-tension-confined (STC) channel with biomimetic microcavities was fabricated facilely through UV exposure photolithography and partial plasma treatment. Perfect asymmetric liquid spreading was achieved by combination of microcavities and hydrophobic boundary, and the stability of pinning effect was demonstrated. The influences of structural features of microcavities on both liquid spreading and liquid pinning were investigated and the underlying mechanism was revealed. We also demonstrated the spontaneous unidirectional transport of liquid in 3D space and on tilting slope. In addition, through changing pits arrangement and wettability pattern, complex liquid motion paths and microreactors were realized. This work will open a new way for liquid manipulation and lab-on-chip applications.

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 Actin-depolymerizing Factor and Cofilin-1 Play Overlapping Roles in Promoting Rapid F-Actin Depolymerization in Mammalian Nonmuscle Cells

2005 ◽  
Vol 16 (2) ◽  
pp. 649-664 ◽  
Author(s):  
Pirta Hotulainen ◽  
Eija Paunola ◽  
Maria K. Vartiainen ◽  
Pekka Lappalainen
Keyword(s):  
Cell Motility ◽  
Actin Filament ◽  
Actin Filaments ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Actin Depolymerizing Factor ◽  
Cytoskeletal Dynamics ◽  
Nonmuscle Cells ◽  
In Cells

Actin-depolymerizing factor (ADF)/cofilins are small actin-binding proteins found in all eukaryotes. In vitro, ADF/cofilins promote actin dynamics by depolymerizing and severing actin filaments. However, whether ADF/cofilins contribute to actin dynamics in cells by disassembling “old” actin filaments or by promoting actin filament assembly through their severing activity is a matter of controversy. Analysis of mammalian ADF/cofilins is further complicated by the presence of multiple isoforms, which may contribute to actin dynamics by different mechanisms. We show that two isoforms, ADF and cofilin-1, are expressed in mouse NIH 3T3, B16F1, and Neuro 2A cells. Depleting cofilin-1 and/or ADF by siRNA leads to an accumulation of F-actin and to an increase in cell size. Cofilin-1 and ADF seem to play overlapping roles in cells, because the knockdown phenotype of either protein could be rescued by overexpression of the other one. Cofilin-1 and ADF knockdown cells also had defects in cell motility and cytokinesis, and these defects were most pronounced when both ADF and cofilin-1 were depleted. Fluorescence recovery after photobleaching analysis and studies with an actin monomer-sequestering drug, latrunculin-A, demonstrated that these phenotypes arose from diminished actin filament depolymerization rates. These data suggest that mammalian ADF and cofilin-1 promote cytoskeletal dynamics by depolymerizing actin filaments and that this activity is critical for several processes such as cytokinesis and cell motility.

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