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Pasquier N, Jaulin F, Peglion F. Inverted apicobasal polarity in health and disease. J Cell Sci 2024; 137:jcs261659. [PMID: 38465512 PMCID: PMC10984280 DOI: 10.1242/jcs.261659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024] Open
Abstract
Apicobasal epithelial polarity controls the functional properties of most organs. Thus, there has been extensive research on the molecular intricacies governing the establishment and maintenance of cell polarity. Whereas loss of apicobasal polarity is a well-documented phenomenon associated with multiple diseases, less is known regarding another type of apicobasal polarity alteration - the inversion of polarity. In this Review, we provide a unifying definition of inverted polarity and discuss multiple scenarios in mammalian systems and human health and disease in which apical and basolateral membrane domains are interchanged. This includes mammalian embryo implantation, monogenic diseases and dissemination of cancer cell clusters. For each example, the functional consequences of polarity inversion are assessed, revealing shared outcomes, including modifications in immune surveillance, altered drug sensitivity and changes in adhesions to neighboring cells. Finally, we highlight the molecular alterations associated with inverted apicobasal polarity and provide a molecular framework to connect these changes with the core cell polarity machinery and to explain roles of polarity inversion in health and disease. Based on the current state of the field, failure to respond to extracellular matrix (ECM) cues, increased cellular contractility and membrane trafficking defects are likely to account for most cases of inverted apicobasal polarity.
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Affiliation(s)
- Nicolas Pasquier
- Collective Invasion Team, Inserm U-1279, Gustave Roussy, Villejuif F-94805, France
- Cell Adhesion and Cancer lab, University of Turku, FI-20520 Turku, Finland
| | - Fanny Jaulin
- Collective Invasion Team, Inserm U-1279, Gustave Roussy, Villejuif F-94805, France
| | - Florent Peglion
- Collective Invasion Team, Inserm U-1279, Gustave Roussy, Villejuif F-94805, France
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2
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Clearman KR, Haycraft CJ, Croyle MJ, Collawn JF, Yoder BK. Functions of the primary cilium in the kidney and its connection with renal diseases. Curr Top Dev Biol 2023; 155:39-94. [PMID: 38043952 DOI: 10.1016/bs.ctdb.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The nonmotile primary cilium is a sensory structure found on most mammalian cell types that integrates multiple signaling pathways involved in tissue development and postnatal function. As such, mutations disrupting cilia activities cause a group of disorders referred to as ciliopathies. These disorders exhibit a wide spectrum of phenotypes impacting nearly every tissue. In the kidney, primary cilia dysfunction caused by mutations in polycystin 1 (Pkd1), polycystin 2 (Pkd2), or polycystic kidney and hepatic disease 1 (Pkhd1), result in polycystic kidney disease (PKD), a progressive disorder causing renal functional decline and end-stage renal disease. PKD affects nearly 1 in 1000 individuals and as there is no cure for PKD, patients frequently require dialysis or renal transplantation. Pkd1, Pkd2, and Pkhd1 encode membrane proteins that all localize in the cilium. Pkd1 and Pkd2 function as a nonselective cation channel complex while Pkhd1 protein function remains uncertain. Data indicate that the cilium may act as a mechanosensor to detect fluid movement through renal tubules. Other functions proposed for the cilium and PKD proteins in cyst development involve regulation of cell cycle and oriented division, regulation of renal inflammation and repair processes, maintenance of epithelial cell differentiation, and regulation of mitochondrial structure and metabolism. However, how loss of cilia or cilia function leads to cyst development remains elusive. Studies directed at understanding the roles of Pkd1, Pkd2, and Pkhd1 in the cilium and other locations within the cell will be important for developing therapeutic strategies to slow cyst progression.
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Affiliation(s)
- Kelsey R Clearman
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Courtney J Haycraft
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mandy J Croyle
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States.
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Márquez-Nogueras KM, Vuchkovska V, Kuo IY. Calcium Signaling in Polycystic Kidney Disease- cell death and survival. Cell Calcium 2023; 112:102733. [PMID: 37023534 DOI: 10.1016/j.ceca.2023.102733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/20/2023] [Accepted: 03/30/2023] [Indexed: 04/03/2023]
Abstract
Polycystic kidney disease is typified by cysts in the kidney and extra-renal manifestations including hypertension and heart failure. The main genetic underpinning this disease are loss-of function mutations to the two polycystin proteins, polycystin 1 and polycystin 2. Molecularly, the disease is characterized by changes in multiple signaling pathways including down regulation of calcium signaling, which, in part, is contributed by the calcium permeant properties of polycystin 2. These signaling pathways enable the cystic cells to survive and avoid cell death. This review focuses on the studies that have emerged in the past 5 years describing how the structural insights gained from PC-1 and PC-2 inform the calcium dependent molecular pathways of autophagy and the unfolded protein response that are regulated by the polycystin proteins and how it leads to cell survival and/or cell death.
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Gupta S, Ozimek-Kulik JE, Phillips JK. Nephronophthisis-Pathobiology and Molecular Pathogenesis of a Rare Kidney Genetic Disease. Genes (Basel) 2021; 12:genes12111762. [PMID: 34828368 PMCID: PMC8623546 DOI: 10.3390/genes12111762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 12/17/2022] Open
Abstract
The exponential rise in our understanding of the aetiology and pathophysiology of genetic cystic kidney diseases can be attributed to the identification of cystogenic genes over the last three decades. The foundation of this was laid by positional cloning strategies which gradually shifted towards next-generation sequencing (NGS) based screenings. This shift has enabled the discovery of novel cystogenic genes at an accelerated pace unlike ever before and, most notably, the past decade has seen the largest increase in identification of the genes which cause nephronophthisis (NPHP). NPHP is a monogenic autosomal recessive cystic kidney disease caused by mutations in a diverse clade of over 26 identified genes and is the most common genetic cause of renal failure in children. NPHP gene types present with some common pathophysiological features alongside a diverse range of extra-renal phenotypes associated with specific syndromic presentations. This review provides a timely update on our knowledge of this disease, including epidemiology, pathophysiology, anatomical and molecular features. We delve into the diversity of the NPHP causing genes and discuss known molecular mechanisms and biochemical pathways that may have possible points of intersection with polycystic kidney disease (the most studied renal cystic pathology). We delineate the pathologies arising from extra-renal complications and co-morbidities and their impact on quality of life. Finally, we discuss the current diagnostic and therapeutic modalities available for disease management, outlining possible avenues of research to improve the prognosis for NPHP patients.
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Affiliation(s)
- Shabarni Gupta
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia; (J.E.O.-K.); (J.K.P.)
- Correspondence:
| | - Justyna E. Ozimek-Kulik
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia; (J.E.O.-K.); (J.K.P.)
- School of Women’s and Children’s Health, University of New South Wales, Sydney, NSW 2031, Australia
- Department of Paediatric Nephrology, Sydney Children’s Hospital Network, Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Jacqueline Kathleen Phillips
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia; (J.E.O.-K.); (J.K.P.)
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Matsuo H, Katayama K, Hayasaki A, Iizawa Y, Endo M, Murata T, Mizuno S, Dohi K. Biliary peritonitis due to liver cyst rupture in autosomal dominant polycystic kidney disease. BMC Gastroenterol 2021; 21:267. [PMID: 34167461 PMCID: PMC8223295 DOI: 10.1186/s12876-021-01845-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/14/2021] [Indexed: 11/23/2022] Open
Abstract
Background Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent genetic kidney disease and polycystic liver disease is its major extrarenal manifestation, however biliary peritonitis due to a liver cyst rupture is extremely rare. Case presentation The patient was a 71-year-old Japanese woman who was diagnosed with ADPKD 3 years previously and developed right abdominal pain suddenly 1 month previously. As abdominal computed tomography (CT) showed a ruptured liver cyst in the right lobe, she was admitted to our hospital. Her symptoms improved with conservative management and she was discharged from the hospital after 1 week. Although she was asymptomatic for a while, she noticed abdominal distension and general malaise at 1 month after hospital discharge. Since abdominal CT showed massive ascites, she was admitted to our hospital again. A physical examination revealed abdominal distention without tenderness. Her serum creatinine, alkaline phosphatase, γ-glutamyl transpeptidase, total bilirubin, and CA19-9 were elevated. Abdominal paracentesis revealed amber transparent ascites and the bilirubin and CA19-9 concentrations were high. She was diagnosed with biliary peritonitis due to a ruptured liver cyst. Hemodialysis treatment was initiated with drainage of the ascites. The outflow of the ascites was no tendency to decrease and drip infusion cholangiography (DIC)-CT revealed a communication between the ruptured cyst and an intrahepatic bile duct. On day 31, she was transferred to a university hospital and abdominal surgery was performed. After removing the necrotic roof of the ruptured cyst on the right liver lobe, the orifice of the bile leakage was sutured. Cholecystectomy was performed and cholangiography showed no stones in the common bile duct. Abdominal CT one month after the operation showed no recurrence of ascites and she was discharged on day 49. Hemodialysis treatment was discontinued immediately after discharge because urine volume increased and her creatinine level decreased. There has been no recurrence of ascites since then.
Conclusions While rare, biliary peritonitis can occur in association with the rupture of a liver cyst in ADPKD patients due to communication between the cyst and the intrahepatic bile duct, and DIC-CT should be recommended when biliary cyst rupture is suspected.
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Affiliation(s)
- Hiroshi Matsuo
- Kidney Center, Suzuka Kaisei Hospital, Suzuka, Japan.,Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
| | - Kan Katayama
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
| | - Aoi Hayasaki
- Department of Hepatobiliary Pancreatic and Transplant Surgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Yusuke Iizawa
- Department of Hepatobiliary Pancreatic and Transplant Surgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Mayumi Endo
- Kidney Center, Suzuka Kaisei Hospital, Suzuka, Japan.,Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
| | - Tomohiro Murata
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
| | - Shugo Mizuno
- Department of Hepatobiliary Pancreatic and Transplant Surgery, Mie University Graduate School of Medicine, Tsu, Japan
| | - Kaoru Dohi
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
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McMellen A, Woodruff ER, Corr BR, Bitler BG, Moroney MR. Wnt Signaling in Gynecologic Malignancies. Int J Mol Sci 2020; 21:E4272. [PMID: 32560059 DOI: 10.3390/ijms21124272] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/12/2020] [Accepted: 06/13/2020] [Indexed: 12/24/2022] Open
Abstract
Gynecologic malignancies, including ovarian cancer, endometrial cancer, and cervical cancer, affect hundreds of thousands of women worldwide every year. Wnt signaling, specifically Wnt/β-catenin signaling, has been found to play an essential role in many oncogenic processes in gynecologic malignancies, including tumorigenesis, metastasis, recurrence, and chemotherapy resistance. As such, the Wnt/β-catenin signaling pathway has the potential to be a target for effective treatment, improving patient outcomes. In this review, we discuss the evidence supporting the importance of the Wnt signaling pathways in the development, progression, and treatment of gynecologic malignancies.
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Axelrod JD. Planar cell polarity signaling in the development of left–right asymmetry. Curr Opin Cell Biol 2020; 62:61-69. [DOI: 10.1016/j.ceb.2019.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 08/27/2019] [Accepted: 09/10/2019] [Indexed: 11/27/2022]
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Franklin-Murray AL, Mallya S, Jankeel A, Sureshchandra S, Messaoudi I, Lodoen MB. Toxoplasma gondii Dysregulates Barrier Function and Mechanotransduction Signaling in Human Endothelial Cells. mSphere 2020; 5:e00550-19. [PMID: 31996420 PMCID: PMC6992369 DOI: 10.1128/msphere.00550-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 01/07/2020] [Indexed: 01/15/2023] Open
Abstract
Toxoplasma gondii can infect and replicate in vascular endothelial cells prior to entering host tissues. However, little is known about the molecular interactions at the parasite-endothelial cell interface. We demonstrate that T. gondii infection of primary human umbilical vein endothelial cells (HUVEC) altered cell morphology and dysregulated barrier function, increasing permeability to low-molecular-weight polymers. T. gondii disrupted vascular endothelial cadherin (VE-cadherin) and β-catenin localization to the cell periphery and reduced VE-cadherin protein expression. Notably, T. gondii infection led to reorganization of the host cytoskeleton by reducing filamentous actin (F-actin) stress fiber abundance under static and microfluidic shear stress conditions and by reducing planar cell polarity. RNA sequencing (RNA-Seq) comparing genome-wide transcriptional profiles of infected to uninfected endothelial cells revealed changes in gene expression associated with cell-cell adhesion, extracellular matrix reorganization, and cytokine-mediated signaling. In particular, genes downstream of Hippo signaling and the biomechanical sensor and transcriptional coactivator Yes-associated protein (YAP) were downregulated in infected endothelial cells. Interestingly, T. gondii infection activated Hippo signaling by increasing phosphorylation of LATS1, leading to cytoplasmic retention of YAP, and reducing YAP target gene expression. These findings suggest that T. gondii infection triggers Hippo signaling and YAP nuclear export, leading to an altered transcriptional profile of infected endothelial cells.IMPORTANCE Toxoplasma gondii is a foodborne parasite that infects virtually all warm-blooded animals and can cause severe disease in individuals with compromised or weakened immune systems. During dissemination in its infected hosts, T. gondii breaches endothelial barriers to enter tissues and establish the chronic infections underlying the most severe manifestations of toxoplasmosis. The research presented here examines how T. gondii infection of primary human endothelial cells induces changes in cell morphology, barrier function, gene expression, and mechanotransduction signaling under static conditions and under the physiological conditions of shear stress found in the bloodstream. Understanding the molecular interactions occurring at the interface between endothelial cells and T. gondii may provide insights into processes linked to parasite dissemination and pathogenesis.
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Affiliation(s)
- Armond L Franklin-Murray
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California, USA
- Institute for Immunology, University of California, Irvine, California, USA
| | - Sharmila Mallya
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California, USA
- Institute for Immunology, University of California, Irvine, California, USA
| | - Allen Jankeel
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California, USA
- Institute for Immunology, University of California, Irvine, California, USA
| | - Suhas Sureshchandra
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California, USA
- Institute for Immunology, University of California, Irvine, California, USA
| | - Ilhem Messaoudi
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California, USA
- Institute for Immunology, University of California, Irvine, California, USA
| | - Melissa B Lodoen
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California, USA
- Institute for Immunology, University of California, Irvine, California, USA
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9
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Abstract
Hepatocyte nuclear factor-1β (HNF-1β) is an essential transcription factor that regulates the development and function of epithelia in the kidney, liver, pancreas, and genitourinary tract. Humans who carry HNF1B mutations develop heterogeneous renal abnormalities, including multicystic dysplastic kidneys, glomerulocystic kidney disease, renal agenesis, renal hypoplasia, and renal interstitial fibrosis. In the embryonic kidney, HNF-1β is required for ureteric bud branching, initiation of nephrogenesis, and nephron segmentation. Ablation of mouse Hnf1b in nephron progenitors causes defective tubulogenesis, whereas later inactivation in elongating tubules leads to cyst formation due to downregulation of cystic disease genes, including Umod, Pkhd1, and Pkd2. In the adult kidney, HNF-1β controls the expression of genes required for intrarenal metabolism and solute transport by tubular epithelial cells. Tubular abnormalities observed in HNF-1β nephropathy include hyperuricemia with or without gout, hypokalemia, hypomagnesemia, and polyuria. Recent studies have identified novel post-transcriptional and post-translational regulatory mechanisms that control HNF-1β expression and activity, including the miRNA cluster miR17 ∼ 92 and the interacting proteins PCBD1 and zyxin. Further understanding of the molecular mechanisms upstream and downstream of HNF-1β may lead to the development of new therapeutic approaches in cystic kidney disease and other HNF1B-related renal diseases.
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Affiliation(s)
- Silvia Ferrè
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, Texas, USA,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Peter Igarashi
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA. .,Department of Medicine, University of Minnesota Medical School, 420 Delaware St. SE, MMC 194, Minneapolis, MN, 55455, USA.
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Winokurow N, Schumacher S. A role for polycystin-1 and polycystin-2 in neural progenitor cell differentiation. Cell Mol Life Sci 2019; 76:2851-2869. [PMID: 30895336 DOI: 10.1007/s00018-019-03072-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 02/17/2019] [Accepted: 03/14/2019] [Indexed: 10/27/2022]
Abstract
Polycystin-1 (PC1) and polycystin-2 (PC2) are transmembrane proteins encoded by the Pkd1 and Pkd2 genes, respectively. Mutations in these genes are causative for the development of autosomal-dominant polycystic kidney disease. A prominent feature of this disease is an unbalanced cell proliferation. PC1 and PC2 physically interact to form a complex, which localizes to the primary cilia of renal epithelial cells. Recently, PC1 and PC2 have also been described to be present in primary cilia of radial glial cells (RGCs) and to contribute to the planar cell polarity of late RGCs and E1 ependymal cells. As neural progenitor cells (NPCs), early RGCs have to balance proliferation for expansion, or for self-renewal and differentiation to generate neurons. It is not known whether the polycystins play a role in this process. Here, we show that PC1 and PC2 are expressed in RGCs of the developing mouse cerebral cortex during neurogenesis. Loss-of-function analysis and cell-based assays reveal that a reduction of PC1 or PC2 expression leads to increased NPC proliferation, while the differentiation to neurons becomes impaired. The increased NPC proliferation is preceded by enhanced Notch signaling and accompanied by a rise in the number of symmetric cell divisions. The transcription factor STAT3 seems to be mechanistically important for polycystin signaling in NPCs as either STAT3 knockdown or inhibition of STAT3 function abrogates the increased proliferation driven by reduced polycystin expression. Our findings indicate that PC1 and PC2 are critical for maintaining a balance between proliferation and differentiation of NPCs.
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Affiliation(s)
- Natalie Winokurow
- Institute of Molecular and Cellular Anatomy, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Stefan Schumacher
- Institute of Molecular and Cellular Anatomy, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
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Joshi A, Sahu A, Noronha V, Patil V, Prabhash K. Metastatic Renal Cell Cancer-Systemic Therapy. Indian J Surg Oncol 2018; 9:97-104. [PMID: 29563746 PMCID: PMC5856703 DOI: 10.1007/s13193-018-0721-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 01/04/2018] [Indexed: 10/18/2022] Open
Abstract
Management of metastatic renal cell carcinoma (mRCC) has evolved considerably in the past 10 years due to better understanding of tumor biology. This development has changed mRCC to a chronic progressive disease with several lines of treatment options. The introduction of several new targeted therapies including immunotherapy has improved median overall survival of approximately 1 year to >2 years in mRCC.
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Affiliation(s)
- Amit Joshi
- Department of Medical Oncology, Tata Memorial Hospital, Mumbai, India
| | - Arvind Sahu
- Department of Medical Oncology, Tata Memorial Hospital, Mumbai, India
| | - Vanita Noronha
- Department of Medical Oncology, Tata Memorial Hospital, Mumbai, India
| | - Vijay Patil
- Department of Medical Oncology, Tata Memorial Hospital, Mumbai, India
| | - Kumar Prabhash
- Department of Medical Oncology, Tata Memorial Hospital, Mumbai, India
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12
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Matt GY, Umen JG. Cell-Type Transcriptomes of the Multicellular Green Alga Volvox carteri Yield Insights into the Evolutionary Origins of Germ and Somatic Differentiation Programs. G3 (Bethesda) 2018; 8:531-50. [PMID: 29208647 DOI: 10.1534/g3.117.300253] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Germ-soma differentiation is a hallmark of complex multicellular organisms, yet its origins are not well understood. Volvox carteri is a simple multicellular green alga that has recently evolved a simple germ-soma dichotomy with only two cell-types: large germ cells called gonidia and small terminally differentiated somatic cells. Here, we provide a comprehensive characterization of the gonidial and somatic transcriptomes of V. carteri to uncover fundamental differences between the molecular and metabolic programming of these cell-types. We found extensive transcriptome differentiation between cell-types, with somatic cells expressing a more specialized program overrepresented in younger, lineage-specific genes, and gonidial cells expressing a more generalist program overrepresented in more ancient genes that shared striking overlap with stem cell-specific genes from animals and land plants. Directed analyses of different pathways revealed a strong dichotomy between cell-types with gonidial cells expressing growth-related genes and somatic cells expressing an altruistic metabolic program geared toward the assembly of flagella, which support organismal motility, and the conversion of storage carbon to sugars, which act as donors for production of extracellular matrix (ECM) glycoproteins whose secretion enables massive organismal expansion. V. carteri orthologs of diurnally controlled genes from C. reinhardtii, a single-celled relative, were analyzed for cell-type distribution and found to be strongly partitioned, with expression of dark-phase genes overrepresented in somatic cells and light-phase genes overrepresented in gonidial cells- a result that is consistent with cell-type programs in V. carteri arising by cooption of temporal regulons in a unicellular ancestor. Together, our findings reveal fundamental molecular, metabolic, and evolutionary mechanisms that underlie the origins of germ-soma differentiation in V. carteri and provide a template for understanding the acquisition of germ-soma differentiation in other multicellular lineages.
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Abstract
Wnt signal cascade is an evolutionarily conserved, developmental pathway that regulates embryogenesis, injury repair, and pathogenesis of human diseases. It is well established that Wnt ligands transmit their signal via canonical, β-catenin-dependent and noncanonical, β-catenin-independent mechanisms. Mounting evidence has revealed that Wnt signaling plays a key role in controlling early nephrogenesis and is implicated in the development of various kidney disorders. Dysregulations of Wnt expression cause a variety of developmental abnormalities and human diseases, such as congenital anomalies of the kidney and urinary tract, cystic kidney, and renal carcinoma. Multiple Wnt ligands, their receptors, and transcriptional targets are upregulated during nephron formation, which is crucial for mediating the reciprocal interaction between primordial tissues of ureteric bud and metanephric mesenchyme. Renal cysts are also associated with disrupted Wnt signaling. In addition, Wnt components are important players in renal tumorigenesis. Activation of Wnt/β-catenin is instrumental for tubular repair and regeneration after acute kidney injury. However, sustained activation of this signal cascade is linked to chronic kidney diseases and renal fibrosis in patients and experimental animal models. Mechanistically, Wnt signaling controls a diverse array of biologic processes, such as cell cycle progression, cell polarity and migration, cilia biology, and activation of renin-angiotensin system. In this chapter, we have reviewed recent findings that implicate Wnt signaling in kidney development and diseases. Targeting this signaling may hold promise for future treatment of kidney disorders in patients.
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Affiliation(s)
- Yongping Wang
- National Clinical Research Center of Kidney Disease, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China
| | - Chengji J Zhou
- University of California Davis, Sacramento, CA, United States
| | - Youhua Liu
- National Clinical Research Center of Kidney Disease, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China; University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
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15
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Abstract
To investigate mechanical-dependent bone remodeling, we had previously applied various types of mechanical loading onto the teeth of rats and mice. In vitro cultured bone cells were then used to elucidate the mechanisms underlying the specific phenomenon revealed by in vivo experiments. This review describes the techniques used to upregulate CCN2 expression in bone cells produced by different types of mechanical stress, such as fluid shear stress and substrate strain in vitro, and compression or tension force in vivo.
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Affiliation(s)
- Teruko Takano-Yamamoto
- Division of Orthodontics and Dentofacial Orthopedics, Tohoku University Graduate School of Dentistry, 4-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
| | - Tomohiro Fukunaga
- Division of Orthodontics and Dentofacial Orthopedics, Tohoku University Graduate School of Dentistry, 4-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Nobuo Takeshita
- Division of Orthodontics and Dentofacial Orthopedics, Tohoku University Graduate School of Dentistry, 4-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
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16
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Mahale S, Kumar M, Sharma A, Babu A, Ranjan S, Sachidanandan C, Mylavarapu SVS. The Light Intermediate Chain 2 Subpopulation of Dynein Regulates Mitotic Spindle Orientation. Sci Rep 2016; 6:22. [PMID: 28003657 PMCID: PMC5431351 DOI: 10.1038/s41598-016-0030-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 11/03/2016] [Indexed: 12/11/2022] Open
Abstract
Cytoplasmic dynein 1 is a multi-protein intracellular motor essential for mediating several mitotic functions, including the establishment of proper spindle orientation. The functional relevance and mechanistic distinctions between two discrete dynein subpopulations distinguished only by Light Intermediate Chain (LIC) homologues, LIC1 and LIC2 is unknown during mitosis. Here, we identify LIC2-dynein as the major mediator of proper spindle orientation and uncover its underlying molecular mechanism. Cortically localized dynein, essential for maintaining correct spindle orientation, consists majorly of LIC2-dynein, which interacts with cortical 14-3-3 ε- ζ and Par3, conserved proteins required for orienting the spindle. LIC2-dynein is also responsible for the majority of dynein-mediated asymmetric poleward transport of NuMA, helping focus microtubule minus ends. In addition, LIC2-dynein dominates in equatorially aligning chromosomes at metaphase and in regulating mitotic spindle length. Key mitotic functions of LIC2 were remarkably conserved in and essential for early embryonic divisions and development in zebrafish. Thus LIC2-dynein exclusively engages with two major cortical pathways to govern spindle orientation. Overall, we identify a novel selectivity of molecular interactions between the two LICs in mitosis as the underlying basis for their uneven distribution of labour in ensuring proper spindle orientation.
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Affiliation(s)
- Sagar Mahale
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, 121001, India.,Affiliated to Manipal University, Manipal, Karnataka, 576104, India
| | - Megha Kumar
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, 121001, India
| | - Amit Sharma
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, 121001, India.,Affiliated to Manipal University, Manipal, Karnataka, 576104, India
| | - Aswini Babu
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India.,Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110025, India
| | - Shashi Ranjan
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India
| | - Chetana Sachidanandan
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India.,Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110025, India
| | - Sivaram V S Mylavarapu
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, 121001, India. .,Affiliated to Manipal University, Manipal, Karnataka, 576104, India.
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17
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Abstract
Oral-facial-digital syndrome type I (OFDI) is an X-linked syndrome, which has several craniofacial and limb features; and hence, patients frequently present to craniofacial and plastic surgeons. Oral-facial-digital syndrome type I is caused by mutations in the CXORF5 gene. The gene product is one of the basal body proteins of a slim microtubule-based organelle called the “primary cilium”. Most of the clinical features of OFDI patients are related to dysfunctions of the primary cilium leading to abnormal Hedgehog signal transduction, depressed planar cell polarity pathway, and errors in cell cycle control.
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Affiliation(s)
- Wael M AlKattan
- Department of Surgery, Alfaisal University, Riyadh, Kingdom of Saudi Arabia. E-mail.
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18
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Suizu F, Hirata N, Kimura K, Edamura T, Tanaka T, Ishigaki S, Donia T, Noguchi H, Iwanaga T, Noguchi M. Phosphorylation-dependent Akt-Inversin interaction at the basal body of primary cilia. EMBO J 2016; 35:1346-63. [PMID: 27220846 PMCID: PMC4883026 DOI: 10.15252/embj.201593003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 04/06/2016] [Indexed: 01/01/2023] Open
Abstract
A primary cilium is a microtubule‐based sensory organelle that plays an important role in human development and disease. However, regulation of Akt in cilia and its role in ciliary development has not been demonstrated. Using yeast two‐hybrid screening, we demonstrate that Inversin (INVS) interacts with Akt. Mutation in the INVS gene causes nephronophthisis type II (NPHP2), an autosomal recessive chronic tubulointerstitial nephropathy. Co‐immunoprecipitation assays show that Akt interacts with INVS via the C‐terminus. In vitro kinase assays demonstrate that Akt phosphorylates INVS at amino acids 864–866 that are required not only for Akt interaction, but also for INVS dimerization. Co‐localization of INVS and phosphorylated form of Akt at the basal body is augmented by PDGF‐AA. Akt‐null MEF cells as well as siRNA‐mediated inhibition of Akt attenuated ciliary growth, which was reversed by Akt reintroduction. Mutant phosphodead‐ or NPHP2‐related truncated INVS, which lack Akt phosphorylation sites, suppress cell growth and exhibit distorted lumen formation and misalignment of spindle axis during cell division. Further studies will be required for elucidating functional interactions of Akt–INVS at the primary cilia for identifying the molecular mechanisms underlying NPHP2.
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Affiliation(s)
- Futoshi Suizu
- Division of Cancer Biology, Institute for Genetic Medicine Hokkaido University, Sapporo, Japan
| | - Noriyuki Hirata
- Division of Cancer Biology, Institute for Genetic Medicine Hokkaido University, Sapporo, Japan
| | - Kohki Kimura
- Division of Cancer Biology, Institute for Genetic Medicine Hokkaido University, Sapporo, Japan
| | - Tatsuma Edamura
- Division of Cancer Biology, Institute for Genetic Medicine Hokkaido University, Sapporo, Japan
| | - Tsutomu Tanaka
- Division of Cancer Biology, Institute for Genetic Medicine Hokkaido University, Sapporo, Japan
| | - Satoko Ishigaki
- Division of Cancer Biology, Institute for Genetic Medicine Hokkaido University, Sapporo, Japan
| | - Thoria Donia
- Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt
| | - Hiroko Noguchi
- Department of Pathology, Teine Keijinkai Hospital, Sapporo, Japan
| | - Toshihiko Iwanaga
- Laboratory of Histology and Cytology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masayuki Noguchi
- Division of Cancer Biology, Institute for Genetic Medicine Hokkaido University, Sapporo, Japan
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19
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Stewart K, Gaitan Y, Shafer ME, Aoudjit L, Hu D, Sharma R, Tremblay M, Ishii H, Marcotte M, Stanga D, Tang YC, Boualia SK, Nguyen AH, Takano T, Lamarche-Vane N, Vidal S, Bouchard M. A Point Mutation in p190A RhoGAP Affects Ciliogenesis and Leads to Glomerulocystic Kidney Defects. PLoS Genet 2016; 12:e1005785. [PMID: 26859289 DOI: 10.1371/journal.pgen.1005785] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 12/12/2015] [Indexed: 01/09/2023] Open
Abstract
Rho family GTPases act as molecular switches regulating actin cytoskeleton dynamics. Attenuation of their signaling capacity is provided by GTPase-activating proteins (GAPs), including p190A, that promote the intrinsic GTPase activity of Rho proteins. In the current study we have performed a small-scale ENU mutagenesis screen and identified a novel loss of function allele of the p190A gene Arhgap35, which introduces a Leu1396 to Gln substitution in the GAP domain. This results in decreased GAP activity for the prototypical Rho-family members, RhoA and Rac1, likely due to disrupted ordering of the Rho binding surface. Consequently, Arhgap35-deficient animals exhibit hypoplastic and glomerulocystic kidneys. Investigation into the cystic phenotype shows that p190A is required for appropriate primary cilium formation in renal nephrons. P190A specifically localizes to the base of the cilia to permit axoneme elongation, which requires a functional GAP domain. Pharmacological manipulations further reveal that inhibition of either Rho kinase (ROCK) or F-actin polymerization is able to rescue the ciliogenesis defects observed upon loss of p190A activity. We propose a model in which p190A acts as a modulator of Rho GTPases in a localized area around the cilia to permit the dynamic actin rearrangement required for cilia elongation. Together, our results establish an unexpected link between Rho GTPase regulation, ciliogenesis and glomerulocystic kidney disease.
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20
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Xu Y, Cao J, Huang S, Feng D, Zhang W, Zhu X, Yan X. Characterization of tetratricopeptide repeat-containing proteins critical for cilia formation and function. PLoS One 2015; 10:e0124378. [PMID: 25860617 PMCID: PMC4393279 DOI: 10.1371/journal.pone.0124378] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 03/01/2015] [Indexed: 12/23/2022] Open
Abstract
Cilia formation and function require a special set of trafficking machinery termed intraflagellar transport (IFT), consisting mainly of protein complexes IFT-A, IFT-B, BBSome, and microtubule-dependent molecular motors. Tetratricopeptide repeat-containing (TTC) proteins are widely involved in protein complex formation. Nine of them are known to serve as components of the IFT or BBSome complexes. How many TTC proteins are cilia-related and how they function, however, remain unclear. Here we show that twenty TTC genes were upregulated by at least 2-fold during the differentiation of cultured mouse tracheal epithelial cells (MTECs) into multiciliated cells. Our systematic screen in zebrafish identified four novel TTC genes, ttc4, -9c, -36, and -39c, that are critical for cilia formation and motility. Accordingly, their zebrafish morphants displayed typical ciliopathy-related phenotypes, including curved body, abnormal otolith, hydrocephalus, and defective left-right patterning. The morphants of ttc4 and ttc25, a known cilia-related gene, additionally showed pronephric cyst formation. Immunoprecipitation indicated associations of TTC4, -9c, -25, -36, and -39c with components or entire complexes of IFT-A, IFT-B, or BBSome, implying their participations in IFT or IFT-related activities. Our results provide a global view for the relationship between TTC proteins and cilia.
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Affiliation(s)
- Yanan Xu
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, China
| | - Jingli Cao
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, China
| | - Shan Huang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, China
| | - Di Feng
- School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai, China
| | - Wei Zhang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, China
| | - Xueliang Zhu
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai, China
- * E-mail: (XZ); (XY)
| | - Xiumin Yan
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, China
- * E-mail: (XZ); (XY)
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21
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Abstract
Planar cell polarity, the polarization of cells within the plane of the epithelium, orthogonal to the apical-basal axis, is essential for a growing list of developmental events, and - over the last 15 years - has evolved from a little-studied curiosity in Drosophila to the subject of a substantial research enterprise. In that time, it has been recognized that two molecular systems are responsible for polarization of most tissues: Both the "core" Frizzled system and the "global" Fat/Dachsous/Four-jointed system produce molecular asymmetry within cells, and contribute to morphological polarization. In this review, we discuss recent findings on the molecular mechanism that links "global" directional signals with local coordinated polarity.
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Affiliation(s)
- Milos Galic
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, Germany.,Institute of Medical Physics and Biophysics, University of Münster, Germany
| | - Maja Matis
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, Germany.,Institute of Cell Biology, ZMBE, University of Münster, Germany
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22
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Afelik S, Pool B, Schmerr M, Penton C, Jensen J. Wnt7b is required for epithelial progenitor growth and operates during epithelial-to-mesenchymal signaling in pancreatic development. Dev Biol 2015; 399:204-17. [DOI: 10.1016/j.ydbio.2014.12.031] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 12/24/2014] [Accepted: 12/26/2014] [Indexed: 01/08/2023]
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23
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Kiousi E, Grapsa E. The role of an out-patient renal clinic in renal disease management. J Transl Int Med 2015; 3:3-7. [PMID: 27847878 PMCID: PMC4936470 DOI: 10.4103/2224-4018.154287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The out-patient renal clinic (ORC) represents an important part of the nephrology service in general hospitals. The majority of renal diseases are chronic and patients need a systematic follow-up according to the severity and progression of kidney failure. The most important clinical manifestation is chronic renal failure (CRF) or chronic renal disease (CKD) The management of CKD, apart from medical and nursing services, also involves a number of community structures and financial resources. CRF treatment is costly and is a serious problem for the health systems in the western world. Effective treatment in the early stages aims to decrease the progression of kidney damage and, therefore, to prolong kidney function. Patients with renal failure can be managed as out-patients. The increased number of patients and the complexity of kidney diseases demand the collaboration of other out-patient clinics. The ORC may play an important role in this process. In this article. we present a literature review of the role of ORCs in the management of renal diseases around the world and we also present data based on our experience in our ORC.
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Affiliation(s)
- Eva Kiousi
- Nephrology Department, Aretaieio University Hospital University of Athens, Athens, Greece
| | - Eirini Grapsa
- Nephrology Department, Aretaieio University Hospital University of Athens, Athens, Greece
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24
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Petridou NI, Skourides PA. FAK transduces extracellular forces that orient the mitotic spindle and control tissue morphogenesis. Nat Commun 2014; 5:5240. [PMID: 25341507 DOI: 10.1038/ncomms6240] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 09/11/2014] [Indexed: 01/08/2023] Open
Abstract
Spindle orientation is critical for proper morphogenesis of organs and tissues as well as for the maintenance of tissue morphology. Although significant progress has been made in understanding the mechanisms linking the cell cortex to the spindle and the well-documented role that extracellular forces play in spindle orientation, how such forces are transduced to the cortex remains poorly understood. Here we report that focal adhesion kinase (FAK) is necessary for correct spindle orientation and as a result, indispensable for proper epithelial morphogenesis in the vertebrate embryo. We show that FAK's role in spindle orientation is dependent on its ability to localize at focal adhesions and its interaction with paxillin, but is kinase activity independent. Finally, we present evidence that FAK is required for external force-induced spindle reorientation, suggesting that FAK's involvement in this process stems from a role in the transduction of external forces to the cell cortex.
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Affiliation(s)
- Nicoletta I Petridou
- Laboratory of Developmental Biology and BioImaging, Department of Biological Sciences, University of Cyprus, University Ave 1, Nicosia 2109, Cyprus
| | - Paris A Skourides
- Laboratory of Developmental Biology and BioImaging, Department of Biological Sciences, University of Cyprus, University Ave 1, Nicosia 2109, Cyprus
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25
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Espinha LC, Hoey DA, Fernandes PR, Rodrigues HC, Jacobs CR. Oscillatory fluid flow influences primary cilia and microtubule mechanics. Cytoskeleton (Hoboken) 2014; 71:435-45. [PMID: 25044764 DOI: 10.1002/cm.21183] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 06/29/2014] [Accepted: 07/01/2014] [Indexed: 11/10/2022]
Abstract
Many tissues are sensitive to mechanical stimuli; however, the mechanotransduction mechanism used by cells remains unknown in many cases. The primary cilium is a solitary, immotile microtubule-based extension present on nearly every mammalian cell which extends from the basal body. The cilium is a mechanosensitive organelle and has been shown to transduce fluid flow-induced shear stress in tissues, such as the kidney and bone. The majority of microtubules assemble from the mother centriole (basal body), contributing significantly to the anchoring of the primary cilium. Several studies have attempted to quantify the number of microtubules emanating from the basal body and the results vary depending on the cell type. It has also been shown that cellular response to shear stress depends on microtubular integrity. This study hypothesizes that changing the microtubule attachment of primary cilia in response to a mechanical stimulus could change primary cilia mechanics and, possibly, mechanosensitivity. Oscillatory fluid flow was applied to two different cell types and the microtubule attachment to the ciliary base was quantified. For the first time, an increase in microtubules around primary cilia both with time and shear rate in response to oscillatory fluid flow stimulation was demonstrated. Moreover, it is presented that the primary cilium is required for this loading-induced cellular response. This study has demonstrated a new role for the cilium in regulating alterations in the cytoplasmic microtubule network in response to mechanical stimulation, and therefore provides a new insight into how cilia may regulate its mechanics and thus the cells mechanosensitivity.
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Affiliation(s)
- Lina C Espinha
- LAETA, IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal; Department of Biomedical Engineering, Columbia University, New York, New York
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26
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27
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Aksanov O, Green P, Birk RZ. BBS4 directly affects proliferation and differentiation of adipocytes. Cell Mol Life Sci 2014; 71:3381-92. [DOI: 10.1007/s00018-014-1571-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 01/17/2014] [Accepted: 01/20/2014] [Indexed: 12/23/2022]
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28
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Abstract
Planar cell polarity (PCP) in epithelia, orthogonal to the apical-basal axis, is essential for numerous developmental events and physiological functions. Drosophila model systems have been at the forefront of studies revealing insights into mechanisms regulating PCP and have revealed distinct signaling modules. One of these, involving the atypical cadherins Fat and Dachsous and the ectokinase Four-jointed, appears to link the direction of cell polarization to the tissue axes. We discuss models for the function of this signaling module as well as several unanswered questions that may guide future investigations.
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Affiliation(s)
- Maja Matis
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, USA
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29
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Abstract
The primary cilium is a solitary, immotile microtubule-based extension present on nearly every mammalian cell. This organelle has established mechanosensory roles in several contexts including kidney, liver, and the embryonic node. Mechanical load deflects the cilium, triggering biochemical responses. Defects in cilium function have been associated with numerous human diseases. Recent research has implicated the primary cilium as a mechanosensor in bone. In this review, we discuss the cilium, the growing evidence for its mechanosensory role in bone, and areas of future study.
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Affiliation(s)
- An M Nguyen
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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30
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31
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Abstract
Mutations in inversin cause nephronophthisis type II, an autosomal recessive form of polycystic kidney disease associated with situs inversus, dilatation, and kidney cyst formation. Since cyst formation may represent a planar polarity defect, we investigated whether inversin plays a role in cell division. In developing nephrons from inv-/- mouse embryos we observed heterogeneity of nuclear size, increased cell membrane perimeters, cells with double cilia, and increased frequency of binuclear cells. Depletion of inversin by siRNA in cultured mammalian cells leads to an increase in bi- or multinucleated cells. While spindle assembly, contractile ring formation, or furrow ingression appears normal in the absence of inversin, mitotic cell rounding and the underlying rearrangement of the cortical actin cytoskeleton are perturbed. We find that inversin loss causes extensive filopodia formation in both interphase and mitotic cells. These cells also fail to round up in metaphase. The resultant spindle positioning defects lead to asymmetric division plane formation and cell division. In a cell motility assay, fibroblasts isolated from inv-/- mouse embryos migrate at half the speed of wild-type fibroblasts. Together these data suggest that inversin is a regulator of cortical actin required for cell rounding and spindle positioning during mitosis. Furthermore, cell division defects resulting from improper spindle position and perturbed actin organization contribute to altered nephron morphogenesis in the absence of inversin.
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Affiliation(s)
- Michael E Werner
- Department of Anatomy and Cell Biology, Indiana University, Indianapolis, IN, USA
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32
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Leightner AC, Hommerding CJ, Peng Y, Salisbury JL, Gainullin VG, Czarnecki PG, Sussman CR, Harris PC. The Meckel syndrome protein meckelin (TMEM67) is a key regulator of cilia function but is not required for tissue planar polarity. Hum Mol Genet 2013; 22:2024-40. [PMID: 23393159 DOI: 10.1093/hmg/ddt054] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Meckel syndrome (MKS) is a lethal disorder associated with renal cystic disease, encephalocele, ductal plate malformation and polydactyly. MKS is genetically heterogeneous and part of a growing list of syndromes called ciliopathies, disorders resulting from defective cilia. TMEM67 mutation (MKS3) is a major cause of MKS and the related ciliopathy Joubert syndrome, although the complete etiology of the disease is not well understood. To further investigate MKS3, we analyzed phenotypes in the Tmem67 null mouse (bpck) and in zebrafish tmem67 morphants. Phenotypes similar to those in human MKS and other ciliopathy models were observed, with additional eye, skeletal and inner ear abnormalities characterized in the bpck mouse. The observed disorganized stereociliary bundles in the bpck inner ear and the convergent extension defects in zebrafish morphants are similar to those found in planar cell polarity (PCP) mutants, a pathway suggested to be defective in ciliopathies. However, analysis of classical vertebrate PCP readouts in the bpck mouse and ciliary organization analysis in tmem67 morphants did not support a global loss of planar polarity. Canonical Wnt signaling was upregulated in cyst linings and isolated fibroblasts from the bpck mouse, but was unchanged in the retina and cochlea tissue, suggesting that increased Wnt signaling may only be linked to MKS3 phenotypes associated with elevated proliferation. Together, these data suggest that defective cilia loading, but not a global loss of ciliogenesis, basal body docking or PCP signaling leads to dysfunctional cilia in MKS3 tissues.
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Affiliation(s)
- Amanda C Leightner
- Department of Biochemistry and Molecular Biology, Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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Hermle T, Guida MC, Beck S, Helmstädter S, Simons M. Drosophila ATP6AP2/VhaPRR functions both as a novel planar cell polarity core protein and a regulator of endosomal trafficking. EMBO J 2013; 32:245-59. [PMID: 23292348 DOI: 10.1038/emboj.2012.323] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 11/07/2012] [Indexed: 11/09/2022] Open
Abstract
Planar cell polarity (PCP) controls the orientation of cells within tissues and the polarized outgrowth of cellular appendages. So far, six PCP core proteins including the transmembrane proteins Frizzled (Fz), Strabismus (Stbm) and Flamingo (Fmi) have been identified. These proteins form asymmetric PCP domains at apical junctions of epithelial cells. Here, we demonstrate that VhaPRR, an accessory subunit of the proton pump V-ATPase, directly interacts with the protocadherin Fmi through its extracellular domain. It also shows a striking co-localization with PCP proteins during all pupal wing stages in Drosophila. This localization depends on intact PCP domains. Reversely, VhaPRR is required for stable PCP domains, identifying it as a novel PCP core protein. VhaPRR performs an additional role in vesicular acidification as well as endolysosomal sorting and degradation. Membrane proteins, such as E-Cadherin and the Notch receptor, accumulate at the surface and in intracellular vesicles of cells mutant for VhaPRR. This trafficking defect is shared by other V-ATPase subunits. By contrast, the V-ATPase does not seem to have a direct role in PCP regulation. Together, our results suggest two roles for VhaPRR, one for PCP and another in endosomal trafficking. This dual function establishes VhaPRR as a key factor in epithelial morphogenesis.
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Affiliation(s)
- Tobias Hermle
- Center for Systems Biology (ZBSA), University of Freiburg, Freiburg, Germany.
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34
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Brownlee CW, Rogers GC. Show me your license, please: deregulation of centriole duplication mechanisms that promote amplification. Cell Mol Life Sci 2012; 70:1021-34. [PMID: 22892665 DOI: 10.1007/s00018-012-1102-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 07/13/2012] [Accepted: 07/17/2012] [Indexed: 12/13/2022]
Abstract
Centrosomes are organelles involved in generating and organizing the interphase microtubule cytoskeleton, mitotic spindles and cilia. At the centrosome core are a pair of centrioles, structures that act as the duplicating elements of this organelle. Centrioles function to recruit and organize pericentriolar material which nucleates microtubules. While centrioles are relatively simple in construction, the mechanics of centriole biogenesis remain an important yet poorly understood process. More mysterious still are the regulatory mechanisms that oversee centriole assembly. The fidelity of centriole duplication is critical as defects in either the assembly or number of centrioles promote aneuploidy, primary microcephaly, birth defects, ciliopathies and tumorigenesis. In addition, some pathogens employ mechanisms to promote centriole overduplication to the detriment of the host cell. This review summarizes our current understanding of this important topic, highlighting the need for further study if new therapeutics are to be developed to treat diseases arising from defects of centrosome duplication.
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Affiliation(s)
- Christopher W Brownlee
- Department of Cellular and Molecular Medicine, Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA
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Bellis J, Duluc I, Romagnolo B, Perret C, Faux MC, Dujardin D, Formstone C, Lightowler S, Ramsay RG, Freund JN, De Mey JR. The tumor suppressor Apc controls planar cell polarities central to gut homeostasis. ACTA ACUST UNITED AC 2012; 198:331-41. [PMID: 22851318 PMCID: PMC3413367 DOI: 10.1083/jcb.201204086] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Asymmetric stem cell divisions controlled by Apc in the intestinal crypt result in regulated, anisotropic movement of daughter cells away from the niche. The stem cells (SCs) at the bottom of intestinal crypts tightly contact niche-supporting cells and fuel the extraordinary tissue renewal of intestinal epithelia. Their fate is regulated stochastically by populational asymmetry, yet whether asymmetrical fate as a mode of SC division is relevant and whether the SC niche contains committed progenitors of the specialized cell types are under debate. We demonstrate spindle alignments and planar cell polarities, which form a novel functional unit that, in SCs, can yield daughter cell anisotropic movement away from niche-supporting cells. We propose that this contributes to SC homeostasis. Importantly, we demonstrate that some SC divisions are asymmetric with respect to cell fate and provide data suggesting that, in some SCs, mNumb displays asymmetric segregation. Some of these processes were altered in apparently normal crypts and microadenomas of mice carrying germline Apc mutations, shedding new light on the first stages of progression toward colorectal cancer.
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Affiliation(s)
- Julien Bellis
- Laboratoire de Biophotonique et Pharmacologie, Unité Mixte de Recherche 7213, Centre National de la Recherche Scientifique, 67401 Illkirch, France
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Pan J, Seeger-Nukpezah T, Golemis EA. The role of the cilium in normal and abnormal cell cycles: emphasis on renal cystic pathologies. Cell Mol Life Sci 2012; 70:1849-74. [PMID: 22782110 DOI: 10.1007/s00018-012-1052-z] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 05/08/2012] [Accepted: 06/05/2012] [Indexed: 12/28/2022]
Abstract
The primary cilium protrudes from the cell surface and acts as a sensor for chemical and mechanical growth cues, with receptors for a number of growth factors (PDGFα, Hedgehog, Wnt, Notch) concentrated within the ciliary membrane. In normal tissues, the cilium assembles after cells exit mitosis and is resorbed as part of cell cycle re-entry. Although regulation of the cilium by cell cycle transitions has been appreciated for over 100 years, only recently have data emerged to indicate the cilium also exerts influence on the cell cycle. The resorption/protrusion cycle, regulated by proteins including Aurora-A, VHL, and GSK-3β, influences cell responsiveness to growth cues involving cilia-linked receptors; further, resorption liberates the ciliary basal body to differentiate into the centrosome, which performs discrete functions in S-, G2-, and M-phase. Besides these roles, the cilium provides a positional cue that regulates polarity of cell division, and thus directs cells towards fates of differentiation versus proliferation. In this review, we summarize the specific mechanisms mediating the cilia-cell cycle dialog. We then emphasize the examples of polycystic kidney disease (PKD), nephronopthisis (NPHP), and VHL-linked renal cysts as cases in which defects of ciliary function influence disease pathology, and may also condition response to treatment.
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Affiliation(s)
- Junmin Pan
- Protein Science Laboratory of the Ministry of Education, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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Wilmes J, Haddad-Tóvolli R, Alesutan I, Munoz C, Sopjani M, Pelzl L, Bogatikov E, Fedele G, Faggio C, Seebohm G, Föller M, Lang F. Regulation of KCNQ1/KCNE1 by β-catenin. Mol Membr Biol 2012; 29:87-94. [PMID: 22583083 DOI: 10.3109/09687688.2012.678017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
β-catenin, a multifunctional protein expressed in all tissues including the heart stimulates the expression of several genes important for cell proliferation. Signaling involving ß-catenin participates in directing cardiac development and in the pathophysiology of cardiac hypertrophy. Nothing is known, however, on the role of β-catenin in the regulation of cardiac ion channels. The present study explored the functional interaction of β-catenin and KCNE1/KCNQ1, the K⁺ channel complex underlying the slowly activating outwardly rectifying K⁺ current. To this end, KCNE1/KCNQ1 was expressed in Xenopus oocytes with and without β-catenin and the depolarization (up to + 80 mV) induced current (I(Ks)) was determined using the two-electrode voltage clamp. As a result, β-catenin enhanced I(Ks) by 30%. The effect of β-catenin on I(Ks) was not affected by actinomycin D (10 μM), an inhibitor of transcription, indicating that β-catenin was not effective as transcription factor. Confocal microscopy revealed that β-catenin enhanced the KCNE1/KCNQ1 protein abundance in the cell membrane. Exposure of the oocytes to brefeldin A (5 μM), an inhibitor of vesicle insertion, was followed by a decline of I(Ks), which was then similar in oocytes expressing KCNE1/KCNQ1 together with β-catenin and in oocytes expressing KCNE1/KCNQ1 alone. In conclusion, β-catenin enhances I(Ks) by increasing the KCNE1/KCNQ1 protein abundance in the cell membrane, an effect requiring vesicle insertion into the cell membrane.
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Affiliation(s)
- Jan Wilmes
- Department of Physiology, University of Tübingen, Tübingen, Germany
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38
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Abstract
Cilia are antenna-like organelles found on the surface of most cells. They transduce molecular signals and facilitate interactions between cells and their environment. Ciliary dysfunction has been shown to underlie a broad range of overlapping, clinically and genetically heterogeneous phenotypes, collectively termed ciliopathies. Literally, all organs can be affected. Frequent cilia-related manifestations are (poly)cystic kidney disease, retinal degeneration, situs inversus, cardiac defects, polydactyly, other skeletal abnormalities, and defects of the central and peripheral nervous system, occurring either isolated or as part of syndromes. Characterization of ciliopathies and the decisive role of primary cilia in signal transduction and cell division provides novel insights into tumorigenesis, mental retardation, and other common causes of morbidity and mortality, including diabetes mellitus and obesity. New technologies ("Next generation sequencing/NGS") have considerably improved genetic research and diagnostics by allowing simultaneous investigation of all disease genes at reduced costs and lower turn-around times. This is undoubtedly a result of the dynamic development in the field of human genetics and deserves increased attention in genetic counselling and the management of affected families.
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Affiliation(s)
- Carsten Bergmann
- Center for Human Genetics Bioscientia, Konrad-Adenauer-Str. 17, 55218 Ingelheim, Germany.
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Abstract
Planar cell polarity (PCP) or tissue polarity describes a coordinated polarity at the plane of the tissue where most or all cells within a tissue are polarized in one direction. It is perpendicular to the apical-basal polarity of the cell. PCP is manifested readily in the Drosophila wing and cuticle bristles, Drosophila eye ommatidia, and mammalian hair and inner ear hair bundles, and less evidently, in cellular processes such as in the coordinated, directional cell movements, and oriented cell divisions that are important for tissue morphogenesis. Several distinct molecular and cellular processes have been implicated in the regulation of PCP. Here, we review potential roles for PCP during mouse kidney development and maintenance, including ureteric bud branching morphogenesis, renal medulla elongation, tubule diameter establishment/maintenance, glomerulogenesis, and response to injury. The potential mechanisms underlying these processes, including oriented cell division and coordinated cell migration/cell intercalation, are discussed. In addition, we discuss some unaddressed research topics related to PCP in the kidney that we hope will spur further discussion and investigation.
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Affiliation(s)
- Thomas J Carroll
- Department of Internal Medicine (Nephrology) and Molecular Biology, UT Southwestern Medical Center, Dallas, Texas, USA.
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40
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Abstract
Multicellular tissues and organs often show planar cell polarity (PCP) where the constituent cells align along an axis to form coordinated patterns. Mammalian eye lenses are mainly comprised of epithelial-derived fibre cells, which exhibit highly ordered alignment that is regulated by PCP signaling. Each fibre cell has an apically situated primary cilium and in most cases this is polarized towards the lens anterior pole. Here we describe how to visualize the global cellular alignment of lens fibre cells by examining the suture pattern that is formed by the tips of fibres meeting at the anterior pole. We also describe a method for whole mount preparation, which allows observation of the polarized distribution of primary cilia at the apical surface of lens fibres. Given its relative simplicity, at least in cellular terms, and its requirement for a high degree of precision in cellular alignment and orientation, we predict that the lens will be an excellent model system to help elucidate the role of cilia and PCP components in the development of three-dimensional organization in tissues and organs.
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Hermle T, Petzoldt AG, Simons M. The role of proton transporters in epithelial Wnt signaling pathways. Pediatr Nephrol 2011; 26:1523-7. [PMID: 21380625 DOI: 10.1007/s00467-011-1823-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 01/07/2011] [Accepted: 02/07/2011] [Indexed: 02/06/2023]
Abstract
The planar cell polarity (PCP) pathway polarizes epithelia in the plane of a tissue. It regulates form and function of tissues and manifests itself by the polarized formation of cellular appendages such as epidermal hairs and cilia. Defects in the pathway are often associated with organ malformation and disease. In the kidney, the molecular events leading to cyst formation in polycystic kidney disease involve the PCP pathway. PCP is, however, best understood in Drosophila where genetic screens have identified a group of PCP core proteins including the Wnt receptor Frizzled (Fz), Dishevelled (Dsh), and Flamingo (Fmi). These proteins can localize to opposite parts of the plasma membrane in response to a poorly understood symmetry breaking event. Recent evidence suggests that proton transporters may play a role in regulating the asymmetric localization of PCP core proteins. Several papers have reported that the (pro)renin receptor, which is an associated subunit of the proton pumping V-ATPase, is required for PCP, but also for canonical Wnt signaling. Here, we discuss the implications of these findings for diverse developmental settings.
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Affiliation(s)
- Tobias Hermle
- Center for Systems Biology (ZBSA), University of Freiburg, Habsburgerstrasse 49, 79104, Freiburg, Germany
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Gascue C, Katsanis N, Badano JL. Cystic diseases of the kidney: ciliary dysfunction and cystogenic mechanisms. Pediatr Nephrol 2011; 26:1181-95. [PMID: 21113628 DOI: 10.1007/s00467-010-1697-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 09/15/2010] [Accepted: 10/15/2010] [Indexed: 01/26/2023]
Abstract
Ciliary dysfunction has emerged as a common factor underlying the pathogenesis of both syndromic and isolated kidney cystic disease, an observation that has contributed to the unification of human genetic disorders of the cilium, the ciliopathies. Such grouping is underscored by two major observations: the fact that genes encoding ciliary proteins can contribute causal and modifying mutations across several clinically discrete ciliopathies, and the emerging realization that an understanding of the clinical pathology of one ciliopathy can provide valuable insight into the pathomechanism of renal cyst formation elsewhere in the ciliopathy spectrum. In this review, we discuss and attempt to stratify the different lines of proposed cilia-driven mechanisms for cystogenesis, ranging from mechano- and chemo-sensation, to cell shape and polarization, to the transduction of a variety of signaling cascades. We evaluate both common trends and differences across the models and discuss how each proposed mechanism can contribute to the development of novel therapeutic paradigms.
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Abstract
The major role of the eye lens is to transmit and focus images onto the retina. For this function, the lens needs to develop and maintain the correct shape, notably, the precise curvature and high-level order and organization of its elements. The lens is mainly comprised of highly elongated fiber cells with hexagonal cross-sectional profiles that facilitate regular packing. Collectively, they form concentrically arranged layers around the anterior-posterior polar axis, and their convex curvature contributes to the spheroidal shape of the lens. Although the lens has been a popular system for developmental studies, little is known about the mechanism(s) that underlies the development of its exquisite three-dimensional cellular architecture. In this review, we will describe our recent work, which shows how planar cell polarity (PCP) operates in lens and contributes to its morphogenesis. We believe that the lens will be a useful model system to study PCP in general and gain insights into mechanisms that generate high-level cellular order during development.
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Carvalhosa R, Deambrosis I, Carrera P, Pasquino C, Rigo F, Ferrari M, Lasaponara F, Ranghino A, Biancone L, Segoloni G, Bussolati B, Camussi G. Cystogenic potential of CD133+ progenitor cells of human polycystic kidneys. J Pathol 2011; 225:129-41. [PMID: 21706482 DOI: 10.1002/path.2920] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 03/22/2011] [Accepted: 04/09/2011] [Indexed: 01/24/2023]
Abstract
In autosomal dominant polycystic kidney disease, cysts arise focally and disrupt normal renal tissue leading to renal failure. In the present study, we show that cyst-lining cells express the stem cell marker CD133. CD133+ progenitor cells isolated from polycystic kidney, carrying mutations of PKD genes, showed a dedifferentiated phenotype similar to CD133+ progenitor cells from normal kidney. However, these cells were more proliferative and presented a defective epithelial differentiation phenotype with respect to normal renal CD133+ cells as they were not able to express all tubular epithelial cell markers when cultured in epithelial differentiation medium. Polycystic CD133+ cells, in contrast to normal renal CD133+ cells, formed cysts in vitro in a three-dimensional culture system and in vivo when injected subcutaneously within Matrigel in SCID mice. Rapamycin treatment reduced in vitro proliferation of polycystic CD133+ cells and decreased cystogenesis both in vitro and in vivo. The in vitro epithelial differentiation was only partially improved by rapamycin. These results indicate that polycystic CD133+ cells retain a dedifferentiated phenotype and the ability to generate cysts.
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Affiliation(s)
- Raquel Carvalhosa
- Department of Internal Medicine, Research Center for Experimental Medicine (CeRMS) and Center for Molecular Biotechnology, San Giovanni Battista Hospital, University of Torino, Torino, Italy
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46
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Tasouri E, Tucker KL. Primary cilia and organogenesis: is Hedgehog the only sculptor? Cell Tissue Res 2011; 345:21-40. [PMID: 21638207 DOI: 10.1007/s00441-011-1192-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Accepted: 05/12/2011] [Indexed: 12/23/2022]
Abstract
The primary cilium is a small microtubule-based organelle projecting from the plasma membrane of practically all cells in the mammalian body. In the past 8 years, a flurry of papers has indicated a crucial role of this long-neglected organelle in the development of a wide variety of organs, including derivatives of all three germ layers. A common theme of these studies is the critical dependency of signal transduction of the Hedgehog pathway upon functionally intact cilia to regulate organogenesis. Another common theme is the role that the cilium plays, not necessarily in the determination of the embryonic anlagen of these organs, although this too occurs but rather in the proliferation and morphogenesis of the previously determined organ. We outline the various organ systems that are dependent upon primary cilia for their proper development and we discuss the cilia-dependent roles that Sonic and Indian Hedgehog play in these processes. In addition and most importantly for the field, we discuss the controversial involvement of another major developmental pathway, Wnt signaling, in cilia-dependent organogenesis.
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47
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Abstract
Nephronophthisis (NPHP) is an autosomal recessive cystic kidney disease and a leading genetic cause of established renal failure (ERF) in children and young adults. Early presenting symptoms in children with NPHP include polyuria, nocturia, or secondary enuresis, pointing to a urinary concentrating defect. Renal ultrasound typically shows normal kidney size with increased echogenicity and corticomedullary cysts. Importantly, NPHP is associated with extra renal manifestations in 10-15% of patients. The most frequent extrarenal association is retinal degeneration, leading to blindness. Increasingly, molecular genetic testing is being utilised to diagnose NPHP and avoid the need for a renal biopsy. In this paper, we discuss the latest understanding in the molecular and cellular pathogenesis of NPHP. We suggest an appropriate clinical management plan and screening programme for individuals with NPHP and their families.
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Affiliation(s)
- Roslyn J Simms
- Institute of Human Genetics, International Centre for Life, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
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48
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Ye X, Wang Y, Rattner A, Nathans J. Genetic mosaic analysis reveals a major role for frizzled 4 and frizzled 8 in controlling ureteric growth in the developing kidney. Development 2011; 138:1161-72. [PMID: 21343368 DOI: 10.1242/dev.057620] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The developing mammalian kidney is an attractive system in which to study the control of organ growth. Targeted mutations in the Wnt receptors frizzled (Fz) 4 and Fz8 lead to reduced ureteric bud growth and a reduction in kidney size, a phenotype previously reported for loss of Wnt11. In cell culture, Fz4 and Fz8 can mediate noncanonical signaling stimulated by Wnt11, but only Fz4 mediates Wnt11-stimulated canonical signaling. In genetically mosaic mouse ureteric buds, competition between phenotypically mutant Fz4(-/-) or Fz4(-/-);Fz8(-/-) cells and adjacent phenotypically wild-type Fz4(+/-) or Fz4(+/-);Fz8(-/-) cells results in under-representation of the mutant cells to an extent far greater than would be predicted from the size reduction of homogeneously mutant kidneys. This discrepancy presumably reflects the compensatory action of a network of growth regulatory systems that minimize developmental perturbations. The present work represents the first description of a kidney phenotype referable to one or more Wnt receptors and demonstrates a general strategy for revealing the contribution of an individual growth regulatory pathway when it is part of a larger homeostatic network.
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Affiliation(s)
- Xin Ye
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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49
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Abstract
A growing list of medically important developmental defects and disease mechanisms can be traced to disruption of the planar cell polarity (PCP) pathway. The PCP system polarizes cells in epithelial sheets along an axis orthogonal to their apical-basal axis. Studies in the fruitfly, Drosophila, have suggested that components of the PCP signaling system function in distinct modules, and that these modules and the effector systems with which they interact function together to produce emergent patterns. Experimental methods allow the manipulation of individual PCP signaling molecules in specified groups of cells; these interventions not only perturb the polarization of the targeted cells at a subcellular level, but also perturb patterns of polarity at the multicellular level, often affecting nearby cells in characteristic ways. These kinds of experiments should, in principle, allow one to infer the architecture of the PCP signaling system, but the relationships between molecular interactions and tissue-level pattern are sufficiently complex that they defy intuitive understanding. Mathematical modeling has been an important tool to address these problems. This article explores the emergence of a local signaling hypothesis, and describes how a local intercellular signal, coupled with a directional cue, can give rise to global pattern. We will discuss the critical role mathematical modeling has played in guiding and interpreting experimental results, and speculate about future roles for mathematical modeling of PCP. Mathematical models at varying levels of inhibition have and are expected to continue contributing in distinct ways to understanding the regulation of PCP signaling.
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Affiliation(s)
- Jeffrey D Axelrod
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA.
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50
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Abstract
Centrioles are conserved microtubule-based organelles that lie at the core of the animal centrosome and play a crucial role in nucleating the formation of cilia and flagella in most eukaryotes. Centrioles have a complex ultrastructure with ninefold symmetry and a well-defined length. This structure is assembled from a host of proteins, including a variety of disease gene products. Over a century after the discovery of centrioles, the mechanisms underlying the assembly of these fascinating organelles, in particular the establishment of ninefold symmetry and the control of centriole length, are now starting to be uncovered.
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Affiliation(s)
- Juliette Azimzadeh
- Department of Biochemistry and Biophysics, University of California, San Francisco, 94143, USA
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