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Ning K, Tran M, Kowal TJ, Mesentier-Louro LA, Sendayen BE, Wang Q, Lo CH, Li T, Majumder R, Luo J, Hu Y, Liao YJ, Sun Y. Compartmentalized ciliation changes of oligodendrocytes in aged mouse optic nerve. J Neurosci Res 2024; 102:e25273. [PMID: 38284846 PMCID: PMC10827352 DOI: 10.1002/jnr.25273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 10/11/2023] [Accepted: 10/28/2023] [Indexed: 01/30/2024]
Abstract
Primary cilia are microtubule-based sensory organelles that project from the apical surface of most mammalian cells, including oligodendrocytes, which are myelinating cells of the central nervous system (CNS) that support critical axonal function. Dysfunction of CNS glia is associated with aging-related white matter diseases and neurodegeneration, and ciliopathies are known to affect CNS white matter. To investigate age-related changes in ciliary profile, we examined ciliary length and frequency in the retinogeniculate pathway, a white matter tract commonly affected by diseases of aging but in which expression of cilia has not been characterized. We found expression of Arl13b, a marker of primary cilia, in a small group of Olig2-positive oligodendrocytes in the optic nerve, optic chiasm, and optic tract in young and aged C57BL/6 wild-type mice. While the ciliary length and ciliated oligodendrocyte cells were constant in young mice in the retinogeniculate pathway, there was a significant increase in ciliary length in the anterior optic nerve as compared to the aged animals. Morphometric analysis confirmed a specific increase in the ciliation rate of CC1+ /Olig2+ oligodendrocytes in aged mice compared with young mice. Thus, the prevalence of primary cilia in oligodendrocytes in the visual pathway and the age-related changes in ciliation suggest that they may play important roles in white matter and age-associated optic neuropathies.
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Affiliation(s)
- Ke Ning
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Matthew Tran
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Tia J. Kowal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
- Veterans Administration Palo Alto Health Care System, Palo Alto, CA, USA
| | | | - Brent E. Sendayen
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Qing Wang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Chien-Hui Lo
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Tingting Li
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Rishab Majumder
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
- Veterans Administration Palo Alto Health Care System, Palo Alto, CA, USA
| | - Jian Luo
- Veterans Administration Palo Alto Health Care System, Palo Alto, CA, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Yaping Joyce Liao
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
- Veterans Administration Palo Alto Health Care System, Palo Alto, CA, USA
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Abstract
PURPOSE OF REVIEW The purpose of this review is to provide a background on osteocytes and the primary cilium, discussing the role it plays in osteocyte mechanosensing. RECENT FINDINGS Osteocytes are thought to be the primary mechanosensing cells in bone tissue, regulating bone adaptation in response to exercise, with the primary cilium suggested to be a key mechanosensing mechanism in bone. More recent work has suggested that, rather than being direct mechanosensors themselves, primary cilia in bone may instead form a key chemo-signalling nexus for processing mechanoregulated signalling pathways. Recent evidence suggests that pharmacologically induced lengthening of the primary cilium in osteocytes may potentiate greater mechanotransduction, rather than greater mechanosensing. While more research is required to delineate the specific osteocyte mechanobiological molecular mechanisms governed by the primary cilium, it is clear from the literature that the primary cilium has significant potential as a therapeutic target to treat mechanoregulated bone diseases, such as osteoporosis.
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Affiliation(s)
- Stefaan W Verbruggen
- Department of Mechanical Engineering, University of Sheffield, Sheffield, UK.
- INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, UK.
- Centre for Predictive in vitro Models, Centre for Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, London, E1 4NS, UK.
| | - Anuphan Sittichokechaiwut
- Department of Preventive Dentistry, Faculty of Dentistry, Naresuan University, Phitsanulok, Thailand
- Center of Excellence in Biomaterials, Naresuan University, Phitsanulok, Thailand
| | - Gwendolen C Reilly
- INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, UK
- Kroto Research Institute, Department of Materials Science and Engineering, University of Sheffield, Sheffield, UK
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3
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Sutton MM, Duffy MP, Verbruggen SW, Jacobs CR. Osteoclastogenesis Requires Primary Cilia Disassembly and Can Be Inhibited by Promoting Primary Cilia Formation Pharmacologically. Cells Tissues Organs 2023; 213:235-244. [PMID: 37231815 PMCID: PMC10863750 DOI: 10.1159/000531098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/11/2023] [Indexed: 05/27/2023] Open
Abstract
The primary cilium is a solitary, sensory organelle with many roles in bone development, maintenance, and function. In the osteogenic cell lineage, including skeletal stem cells, osteoblasts, and osteocytes, the primary cilium plays a vital role in the regulation of bone formation, and this has made it a promising pharmaceutical target to maintain bone health. While the role of the primary cilium in the osteogenic cell lineage has been increasingly characterized, little is known about the potential impact of targeting the cilium in relation to osteoclasts, a hematopoietic cell responsible for bone resorption. The objective of this study was to determine whether osteoclasts have a primary cilium and to investigate whether or not the primary cilium of macrophages, osteoclast precursors, serves a functional role in osteoclast formation. Using immunocytochemistry, we showed the macrophages have a primary cilium, while osteoclasts lack this organelle. Furthermore, we increased macrophage primary cilia incidence and length using fenoldopam mesylate and found that cells undergoing such treatment showed a significant decrease in the expression of osteoclast markers tartrate-resistant acid phosphatase, cathepsin K, and c-Fos, as well as decreased osteoclast formation. This work is the first to show that macrophage primary cilia resorption may be a necessary step for osteoclast differentiation. Since primary cilia and preosteoclasts are responsive to fluid flow, we applied fluid flow at magnitudes present in the bone marrow to differentiating cells and found that osteoclastic gene expression by macrophages was not affected by fluid flow mechanical stimulation, suggesting that the role of the primary cilium in osteoclastogenesis is not a mechanosensory one. The primary cilium has been suggested to play a role in bone formation, and our findings indicate that it may also present a means to regulate bone resorption, presenting a dual benefit of developing ciliary-targeted pharmaceuticals for bone disease.
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Affiliation(s)
- Michael M. Sutton
- Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, USA
| | - Michael P. Duffy
- Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, USA
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Stefaan W. Verbruggen
- Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, USA
- Centre for Predictive in vitro Models, School of Engineering and Materials Science, Queen Mary University of London, London, UK
- Department of Mechanical Engineering and INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, UK
| | - Christopher R. Jacobs
- Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, USA
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Wang Q, Gu X, Liu Y, Liu S, Lu W, Wu Y, Lu H, Huang J, Tu W. Insights into the circadian rhythm alterations of the novel PFOS substitutes F-53B and OBS on adult zebrafish. JOURNAL OF HAZARDOUS MATERIALS 2023; 448:130959. [PMID: 36860044 DOI: 10.1016/j.jhazmat.2023.130959] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/20/2022] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
As alternatives to perfluorooctane sulfonate (PFOS), 6:2 Cl-PFESA (F-53B) and sodium p-perfluorous nonenoxybenzene sulfonate (OBS) are frequently detected in aquatic environments, but little is known about their neurotoxicity, especially in terms of circadian rhythms. In this study, adult zebrafish were chronically exposed to 1 μM PFOS, F-53B and OBS for 21 days taking circadian rhythm-dopamine (DA) regulatory network as an entry point to comparatively investigate their neurotoxicity and underlying mechanisms. The results showed that PFOS may affect the response to heat rather than circadian rhythms by reducing DA secretion due to disruption of calcium signaling pathway transduction caused by midbrain swelling. In contrast, F-53B and OBS altered the circadian rhythms of adult zebrafish, but their mechanisms of action were different. Specifically, F-53B might alter circadian rhythms by interfering with amino acid neurotransmitter metabolism and disrupting blood-brain barrier (BBB) formation, whereas OBS mainly inhibited canonical Wnt signaling transduction by reducing cilia formation in ependymal cells and induced midbrain ventriculomegaly, finally triggering imbalance in DA secretion and circadian rhythm changes. Our study highlights the need to focus on the environmental exposure risks of PFOS alternatives and the sequential and interactive mechanisms of their multiple toxicities.
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Affiliation(s)
- Qiyu Wang
- Research Institute of Poyang Lake, Jiangxi Academy of Sciences, Nanchang 330012, China
| | - Xueyan Gu
- Research Institute of Poyang Lake, Jiangxi Academy of Sciences, Nanchang 330012, China
| | - Yu Liu
- Research Institute of Poyang Lake, Jiangxi Academy of Sciences, Nanchang 330012, China
| | - Shuai Liu
- Research Institute of Poyang Lake, Jiangxi Academy of Sciences, Nanchang 330012, China
| | - Wuting Lu
- School of Life Science, Nanchang University, Nanchang 330031, China
| | - Yongming Wu
- Research Institute of Poyang Lake, Jiangxi Academy of Sciences, Nanchang 330012, China
| | - Huiqiang Lu
- College of Chemistry and Chemical Engineering, Gannan Normal University, Ganzhou 341000, China
| | - Jing Huang
- School of Land Resources and Environment, Jiangxi Agricultural University, Nanchang 330045, China
| | - Wenqing Tu
- School of Land Resources and Environment, Jiangxi Agricultural University, Nanchang 330045, China.
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5
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Gerhards J, Maerz LD, Matthees ESF, Donow C, Moepps B, Premont RT, Burkhalter MD, Hoffmann C, Philipp M. Kinase Activity Is Not Required for G Protein-Coupled Receptor Kinase 4 Restraining mTOR Signaling during Cilia and Kidney Development. J Am Soc Nephrol 2023; 34:590-606. [PMID: 36810260 PMCID: PMC10103308 DOI: 10.1681/asn.0000000000000082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 11/27/2022] [Indexed: 01/28/2023] Open
Abstract
SIGNIFICANCE STATEMENT G protein-coupled receptor kinase 4 (GRK4) regulates renal sodium and water reabsorption. Although GRK4 variants with elevated kinase activity have been associated with salt-sensitive or essential hypertension, this association has been inconsistent among different study populations. In addition, studies elucidating how GRK4 may modulate cellular signaling are sparse. In an analysis of how GRK4 affects the developing kidney, the authors found that GRK4 modulates mammalian target of rapamycin (mTOR) signaling. Loss of GRK4 in embryonic zebrafish causes kidney dysfunction and glomerular cysts. Moreover, GRK4 depletion in zebrafish and cellular mammalian models results in elongated cilia. Rescue experiments suggest that hypertension in carriers of GRK4 variants may not be explained solely by kinase hyperactivity; instead, elevated mTOR signaling may be the underlying cause. BACKGROUND G protein-coupled receptor kinase 4 (GRK4) is considered a central regulator of blood pressure through phosphorylation of renal dopaminergic receptors and subsequent modulation of sodium excretion. Several nonsynonymous genetic variants of GRK4 have been only partially linked to hypertension, although these variants demonstrate elevated kinase activity. However, some evidence suggests that function of GRK4 variants may involve more than regulation of dopaminergic receptors alone. Little is known about the effects of GRK4 on cellular signaling, and it is also unclear whether or how altered GRK4 function might affect kidney development. METHODS To better understand the effect of GRK4 variants on the functionality of GRK4 and GRK4's actions in cellular signaling during kidney development, we studied zebrafish, human cells, and a murine kidney spheroid model. RESULTS Zebrafish depleted of Grk4 develop impaired glomerular filtration, generalized edema, glomerular cysts, pronephric dilatation, and expansion of kidney cilia. In human fibroblasts and in a kidney spheroid model, GRK4 knockdown produced elongated primary cilia. Reconstitution with human wild-type GRK4 partially rescues these phenotypes. We found that kinase activity is dispensable because kinase-dead GRK4 (altered GRK4 that cannot result in phosphorylation of the targeted protein) prevented cyst formation and restored normal ciliogenesis in all tested models. Hypertension-associated genetic variants of GRK4 fail to rescue any of the observed phenotypes, suggesting a receptor-independent mechanism. Instead, we discovered unrestrained mammalian target of rapamycin signaling as an underlying cause. CONCLUSIONS These findings identify GRK4 as novel regulator of cilia and of kidney development independent of GRK4's kinase function and provide evidence that the GRK4 variants believed to act as hyperactive kinases are dysfunctional for normal ciliogenesis.
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Affiliation(s)
- Julian Gerhards
- Section of Pharmacogenomics, Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Lars D. Maerz
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Edda S. F. Matthees
- Institute for Molecular Cell Biology, University Hospital Jena, Friedrich-Schiller University of Jena, Jena, Germany
| | - Cornelia Donow
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Barbara Moepps
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
| | - Richard T. Premont
- Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Martin D. Burkhalter
- Section of Pharmacogenomics, Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Carsten Hoffmann
- Institute for Molecular Cell Biology, University Hospital Jena, Friedrich-Schiller University of Jena, Jena, Germany
| | - Melanie Philipp
- Section of Pharmacogenomics, Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Eberhard-Karls-University Tübingen, Tübingen, Germany
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6
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Wang W, Silva LM, Wang HH, Kavanaugh MA, Pottorf TS, Allard BA, Jacobs DT, Dong R, Cornelius JT, Chaturvedi A, Swenson-Fields KI, Fields TA, Pritchard MT, Sharma M, Slawson C, Wallace DP, Calvet JP, Tran PV. Ttc21b deficiency attenuates autosomal dominant polycystic kidney disease in a kidney tubular- and maturation-dependent manner. Kidney Int 2022; 102:577-591. [PMID: 35644283 PMCID: PMC9398994 DOI: 10.1016/j.kint.2022.04.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 04/21/2022] [Accepted: 04/29/2022] [Indexed: 01/26/2023]
Abstract
Primary cilia are sensory organelles built and maintained by intraflagellar transport (IFT) multiprotein complexes. Deletion of several IFT-B genes attenuates polycystic kidney disease (PKD) severity in juvenile and adult autosomal dominant polycystic kidney disease (ADPKD) mouse models. However, deletion of an IFT-A adaptor, Tulp3, attenuates PKD severity in adult mice only. These studies indicate that dysfunction of specific cilia components has potential therapeutic value. To broaden our understanding of cilia dysfunction and its therapeutic potential, we investigate the role of global deletion of an IFT-A gene, Ttc21b, in juvenile and adult mouse models of ADPKD. Both juvenile (postnatal day 21) and adult (six months of age) ADPKD mice exhibited kidney cysts, increased kidney weight/body weight ratios, lengthened kidney cilia, inflammation, and increased levels of the nutrient sensor, O-linked β-N-acetylglucosamine (O-GlcNAc). Deletion of Ttc21b in juvenile ADPKD mice reduced cortical collecting duct cystogenesis and kidney weight/body weight ratios, increased proximal tubular and glomerular dilations, but did not reduce cilia length, inflammation, nor O-GlcNAc levels. In contrast, Ttc21b deletion in adult ADPKD mice markedly attenuated kidney cystogenesis and reduced cilia length, inflammation, and O-GlcNAc levels. Thus, unlike IFT-B, the effect of Ttc21b deletion in mouse models of ADPKD is development-specific. Unlike an IFT-A adaptor, deleting Ttc21b in juvenile ADPKD mice is partially ameliorative. Thus, our studies suggest that different microenvironmental factors, found in distinct nephron segments and in developing versus mature stages, modify ciliary homeostasis and ADPKD pathobiology. Further, elevated levels of O-GlcNAc, which regulates cellular metabolism and ciliogenesis, may be a pathological feature of ADPKD.
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Affiliation(s)
- Wei Wang
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Luciane M Silva
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Henry H Wang
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Matthew A Kavanaugh
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Tana S Pottorf
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Bailey A Allard
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Damon T Jacobs
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Rouchen Dong
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Joseph T Cornelius
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Aakriti Chaturvedi
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Katherine I Swenson-Fields
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Timothy A Fields
- Department of Pathology and Laboratory Medicine, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Michele T Pritchard
- Pharmacology, Toxicology and Therapeutics, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Madhulika Sharma
- Department of Internal Medicine, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Chad Slawson
- Department of Biochemistry and Molecular Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Darren P Wallace
- Department of Internal Medicine, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - James P Calvet
- Department of Biochemistry and Molecular Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Pamela V Tran
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA.
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7
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Nam YW, Pala R, El-Sayed NS, Larin-Henriquez D, Amirrad F, Yang G, Rahman MA, Orfali R, Downey M, Parang K, Nauli SM, Zhang M. Subtype-Selective Positive Modulation of K Ca2.3 Channels Increases Cilia Length. ACS Chem Biol 2022; 17:2344-2354. [PMID: 35947779 PMCID: PMC9396613 DOI: 10.1021/acschembio.2c00469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Small-conductance Ca2+-activated potassium
(KCa2.x) channels are gated exclusively by intracellular
Ca2+. The activation of KCa2.3 channels induces
hyperpolarization,
which augments Ca2+ signaling in endothelial cells. Cilia
are specialized Ca2+ signaling compartments. Here, we identified
compound 4 that potentiates human KCa2.3 channels
selectively. The subtype selectivity of compound 4 for
human KCa2.3 over rat KCa2.2a channels relies
on an isoleucine residue in the HA/HB helices. Positive modulation
of KCa2.3 channels by compound 4 increased
flow-induced Ca2+ signaling and cilia length, while negative
modulation by AP14145 reduced flow-induced Ca2+ signaling
and cilia length. These findings were corroborated by the increased
cilia length due to the expression of Ca2+-hypersensitive
KCa2.3_G351D mutant channels and the reduced cilia length
resulting from the expression of Ca2+-hyposensitive KCa2.3_I438N channels. Collectively, we were able to associate
functions of KCa2.3 channels and cilia, two crucial components
in the flow-induced Ca2+ signaling of endothelial cells,
with potential implications in vasodilation and ciliopathic hypertension.
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Affiliation(s)
- Young-Woo Nam
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
| | - Rajasekharreddy Pala
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
| | - Naglaa Salem El-Sayed
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
| | - Denisse Larin-Henriquez
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
| | - Farideh Amirrad
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
| | - Grace Yang
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
| | - Mohammad Asikur Rahman
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
| | - Razan Orfali
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
| | - Myles Downey
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
| | - Keykavous Parang
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
| | - Surya M Nauli
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
| | - Miao Zhang
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, USA
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8
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Spasic M, Duffy MP, Jacobs CR. Fenoldopam Sensitizes Primary Cilia-Mediated Mechanosensing to Promote Osteogenic Intercellular Signaling and Whole Bone Adaptation. J Bone Miner Res 2022; 37:972-982. [PMID: 35230705 PMCID: PMC9098671 DOI: 10.1002/jbmr.4536] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 02/01/2022] [Accepted: 02/12/2022] [Indexed: 11/05/2022]
Abstract
Bone cells actively respond to mechanical stimuli to direct bone formation, yet there is no current treatment strategy for conditions of low bone mass and osteoporosis designed to target the inherent mechanosensitivity of bone. Our group has previously identified the primary cilium as a critical mechanosensor within bone, and that pharmacologically targeting the primary cilium with fenoldopam can enhance osteocyte mechanosensitivity. Here, we demonstrate that potentiating osteocyte mechanosensing with fenoldopam in vitro promotes pro-osteogenic paracrine signaling to osteoblasts. Conversely, impairing primary cilia formation and the function of key ciliary mechanotransduction proteins attenuates this intercellular signaling cascade. We then utilize an in vivo model of load-induced bone formation to demonstrate that fenoldopam treatment sensitizes bones of both healthy and osteoporotic mice to mechanical stimulation. Furthermore, we show minimal adverse effects of this treatment and demonstrate that prolonged treatment biases trabecular bone adaptation. This work is the first to examine the efficacy of targeting primary cilia-mediated mechanosensing to enhance bone formation in osteoporotic animals. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Milos Spasic
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Michael P Duffy
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
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9
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Wang W, Jack BM, Wang HH, Kavanaugh MA, Maser RL, Tran PV. Intraflagellar Transport Proteins as Regulators of Primary Cilia Length. Front Cell Dev Biol 2021; 9:661350. [PMID: 34095126 PMCID: PMC8170031 DOI: 10.3389/fcell.2021.661350] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/06/2021] [Indexed: 12/21/2022] Open
Abstract
Primary cilia are small, antenna-like organelles that detect and transduce chemical and mechanical cues in the extracellular environment, regulating cell behavior and, in turn, tissue development and homeostasis. Primary cilia are assembled via intraflagellar transport (IFT), which traffics protein cargo bidirectionally along a microtubular axoneme. Ranging from 1 to 10 μm long, these organelles typically reach a characteristic length dependent on cell type, likely for optimum fulfillment of their specific roles. The importance of an optimal cilia length is underscored by the findings that perturbation of cilia length can be observed in a number of cilia-related diseases. Thus, elucidating mechanisms of cilia length regulation is important for understanding the pathobiology of ciliary diseases. Since cilia assembly/disassembly regulate cilia length, we review the roles of IFT in processes that affect cilia assembly/disassembly, including ciliary transport of structural and membrane proteins, ectocytosis, and tubulin posttranslational modification. Additionally, since the environment of a cell influences cilia length, we also review the various stimuli encountered by renal epithelia in healthy and diseased states that alter cilia length and IFT.
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Affiliation(s)
- Wei Wang
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Brittany M Jack
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Henry H Wang
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Matthew A Kavanaugh
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Robin L Maser
- Department of Clinical Laboratory Sciences, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
| | - Pamela V Tran
- Department of Anatomy and Cell Biology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, United States
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10
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Signal transduction in primary cilia - analyzing and manipulating GPCR and second messenger signaling. Pharmacol Ther 2021; 224:107836. [PMID: 33744260 DOI: 10.1016/j.pharmthera.2021.107836] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 12/13/2022]
Abstract
The primary cilium projects from the surface of most vertebrate cells, where it senses extracellular signals to regulate diverse cellular processes during tissue development and homeostasis. Dysfunction of primary cilia underlies the pathogenesis of severe diseases, commonly referred to as ciliopathies. Primary cilia contain a unique protein repertoire that is distinct from the cell body and the plasma membrane, enabling the spatially controlled transduction of extracellular cues. G-protein coupled receptors (GPCRs) are key in sensing environmental stimuli that are transmitted via second messenger signaling into a cellular response. Here, we will give an overview of the role of GPCR signaling in primary cilia, and how ciliary GPCR signaling can be targeted by pharmacology, chemogenetics, and optogenetics.
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Kobayashi Y, Hamamoto A, Saito Y. Analysis of ciliary status via G-protein-coupled receptors localized on primary cilia. Microscopy (Oxf) 2020; 69:277-285. [PMID: 32627821 DOI: 10.1093/jmicro/dfaa035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 06/20/2020] [Accepted: 07/02/2020] [Indexed: 11/14/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) comprise the largest and most diverse cell surface receptor family, with more than 800 known GPCRs identified in the human genome. Binding of an extracellular cue to a GPCR results in intracellular G protein activation, after which a sequence of events, can be amplified and optimized by selective binding partners and downstream effectors in spatially discrete cellular environments. Because GPCRs are widely expressed in the body, they help to regulate an incredible range of physiological processes from sensation to growth to hormone responses. Indeed, it is estimated that ∼ 30% of all clinically approved drugs act by binding to GPCRs. The primary cilium is a sensory organelle composed of a microtubule axoneme that extends from the basal body. The ciliary membrane is highly enriched in specific signaling components, allowing the primary cilium to efficiently convey signaling cascades in a highly ordered microenvironment. Recent data demonstrated that a limited number of non-olfactory GPCRs, including somatostatin receptor 3 and melanin-concentrating hormone receptor 1 (MCHR1), are selectively localized to cilia on several mammalian cell types including neuronal cells. Utilizing cilia-specific cell biological and molecular biological approaches, evidence has accumulated to support the biological importance of ciliary GPCR signaling followed by cilia structural changes. Thus, cilia are now considered a unique sensory platform for integration of GPCR signaling toward juxtaposed cytoplasmic structures. Herein, we review ciliary GPCRs and focus on a novel role of MCHR1 in ciliary length control that will impact ciliary signaling capacity and neuronal function.
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Affiliation(s)
- Yuki Kobayashi
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Akie Hamamoto
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu, Gifu 502-0857, Japan
| | - Yumiko Saito
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
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Chikamori M, Kimura H, Inagi R, Zhou J, Nangaku M, Fujii T. Intracellular calcium response of primary cilia of tubular cells to modulated shear stress under oxidative stress. BIOMICROFLUIDICS 2020; 14:044102. [PMID: 32665806 PMCID: PMC7334031 DOI: 10.1063/5.0010737] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Primary cilia of tubular cells are sensory organelles. Bending of the primary cilia with shear stress from urinary flow results in the elevation of intracellular calcium levels and activation of signaling pathways that maintain kidney function. Elongation of primary cilia is reported to occur due to oxidative stress, which is a major cause of ischemia-reperfusion injury and is accompanied by decreased kidney function. However, in the context of diminished kidney function, this elongation is yet to be investigated. In this study, we developed a new microfluidic device to monitor changes in the intracellular calcium levels while modulating shear stress on the cilia under different degrees of oxidative stress. The microfluidic device was designed to expose even shear stress in the observed area while supplying drugs in four different stepwise concentrations. The results showed that primary cilia were elongated by hydrogen peroxide, which induces oxidative stress. It was also observed that the elongated primary cilia were more sensitive to shear stress than those with normal morphology. This microfluidic device could, thus, be useful in the analysis of the morphology of the primary cilia, under low perfusion conditions.
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Affiliation(s)
- Masatomo Chikamori
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan
| | | | - Reiko Inagi
- Department of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Jing Zhou
- Center for Polycystic Kidney Disease Research and Renal Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Masaomi Nangaku
- Department of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Teruo Fujii
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan
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Abstract
Primary cilia project in a single copy from the surface of most vertebrate cell types; they detect and transmit extracellular cues to regulate diverse cellular processes during development and to maintain tissue homeostasis. The sensory capacity of primary cilia relies on the coordinated trafficking and temporal localization of specific receptors and associated signal transduction modules in the cilium. The canonical Hedgehog (HH) pathway, for example, is a bona fide ciliary signalling system that regulates cell fate and self-renewal in development and tissue homeostasis. Specific receptors and associated signal transduction proteins can also localize to primary cilia in a cell type-dependent manner; available evidence suggests that the ciliary constellation of these proteins can temporally change to allow the cell to adapt to specific developmental and homeostatic cues. Consistent with important roles for primary cilia in signalling, mutations that lead to their dysfunction underlie a pleiotropic group of diseases and syndromic disorders termed ciliopathies, which affect many different tissues and organs of the body. In this Review, we highlight central mechanisms by which primary cilia coordinate HH, G protein-coupled receptor, WNT, receptor tyrosine kinase and transforming growth factor-β (TGFβ)/bone morphogenetic protein (BMP) signalling and illustrate how defects in the balanced output of ciliary signalling events are coupled to developmental disorders and disease progression.
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14
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The Role of the Primary Cilium in Sensing Extracellular pH. Cells 2019; 8:cells8070704. [PMID: 31336778 PMCID: PMC6679169 DOI: 10.3390/cells8070704] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 12/12/2022] Open
Abstract
Biosensors on the membrane of the vascular endothelium are responsible for sensing mechanical and chemical signals in the blood. Transduction of these stimuli into intracellular signaling cascades regulate cellular processes including ion transport, gene expression, cell proliferation, and/or cell death. The primary cilium is a well-known biosensor of shear stress but its role in sensing extracellular pH change has never been examined. As a cellular extension into the immediate microenvironment, the cilium could be a prospective sensor for changes in pH and regulator of acid response in cells. We aim to test our hypothesis that the primary cilium plays the role of an acid sensor in cells using vascular endothelial and embryonic fibroblast cells as in vitro models. We measure changes in cellular pH using pH-sensitive 2',7'-biscarboxyethy1-5,6-carboxyfluorescein acetoxy-methylester (BCECF) fluorescence and mitogen-activated protein kinase (MAPK) activity to quantify responses to both extracellular pH (pHo) and intracellular pH (pHi) changes. Our studies show that changes in pHo affect pHi in both wild-type and cilia-less Tg737 cells and that the kinetics of the pHi response are similar in both cells. Acidic pHo or pHi was observed to change the length of primary cilia in wild-type cells while the cilia in Tg737 remained absent. Vascular endothelial cells respond to acidic pH through activation of ERK1/2 and p38-mediated signaling pathways. The cilia-less Tg737 cells exhibit delayed responsiveness to pHo dependent and independent pHi acidification as depicted in the phosphorylation profile of ERK1/2 and p38. Otherwise, intracellular pH homeostatic response to acidic pHo is similar between wild-type and Tg737 cells, indicating that the primary cilia may not be the sole sensor for physiological pH changes. These endothelial cells respond to pH changes with a predominantly K+-dependent pHi recovery mechanism, regardless of ciliary presence or absence.
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15
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Shi W, Ma Z, Zhang G, Wang C, Jiao Z. Novel functions of the primary cilium in bone disease and cancer. Cytoskeleton (Hoboken) 2019; 76:233-242. [PMID: 31108028 DOI: 10.1002/cm.21529] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 05/15/2019] [Accepted: 05/16/2019] [Indexed: 11/09/2022]
Abstract
The primary cilium, a sensory organelle that emanates from the cell surface of most mammalian cell types during growth arrest, has attracted the attention of many researchers over the past decade. Recently, a large number of new findings have assigned novel functions and roles to the primary cilium in signal transduction and related diseases, which has greatly augmented the importance of the cilium in human health and development. Here, we review emerging evidence supporting the primary cilium as a sensory organelle in signal transduction in microgravity, electromagnetic field sensing, chemosensation and tumorigenesis. We also present an overview of signal transduction crosstalk associated with the primary cilium in bone disease and cancer, including primary cilium-related Ca2+ signaling, parathyroid hormone signaling, cAMP signaling, BMP/Smad1/5/8 signaling and Wnt signaling. We anticipate that emerging discoveries about the function of the primary cilium will provide novel insight into the molecular mechanisms of stimulus sensation, signal transduction and pathogenesis.
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Affiliation(s)
- Wengui Shi
- Cuiying Biomedical Research Center, Lanzhou University Second Hospital, Lanzhou, People's Republic of China
| | - Zhijian Ma
- The First Department of General Surgery, Lanzhou University Second Hospital, Lanzhou, People's Republic of China
| | - Gengyuan Zhang
- The First Department of General Surgery, Lanzhou University Second Hospital, Lanzhou, People's Republic of China
| | - Chen Wang
- Cuiying Biomedical Research Center, Lanzhou University Second Hospital, Lanzhou, People's Republic of China.,The First Department of General Surgery, Lanzhou University Second Hospital, Lanzhou, People's Republic of China
| | - Zuoyi Jiao
- Cuiying Biomedical Research Center, Lanzhou University Second Hospital, Lanzhou, People's Republic of China.,The First Department of General Surgery, Lanzhou University Second Hospital, Lanzhou, People's Republic of China
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16
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Abstract
Primary cilia are singular, sensory organelles that extend from the plasma membrane of most quiescent mammalian cells. These slender, microtubule-based organelles receive and transduce extracellular cues and regulate signaling pathways. Primary cilia are critical to the development and function of many tissue types, and mutation of ciliary genes causes multi-system disorders, termed ciliopathies. Notably, renal cystic disease is one of the most common clinical features of ciliopathies, highlighting a central role for primary cilia in the kidney. Additionally, acute kidney injury and chronic kidney disease are associated with altered primary cilia lengths on renal epithelial cells, suggesting ciliary dynamics and renal physiology are linked. Here we describe methods to examine primary cilia in kidney tissue and in cultured renal cells. We include immunofluorescence and scanning electron microscopy to determine ciliary localization of proteins and cilia structure. Further, we detail cellular assays to measure cilia assembly and disassembly, which regulate cilia length.
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Paul P, Ramachandran S, Xia S, Unruh JR, Conkright-Fincham J, Li R. Dopamine receptor antagonists as potential therapeutic agents for ADPKD. PLoS One 2019; 14:e0216220. [PMID: 31059522 PMCID: PMC6502331 DOI: 10.1371/journal.pone.0216220] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 04/16/2019] [Indexed: 12/24/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is caused mostly by mutations in polycystin-1 or polycystin-2. Fluid flow leads to polycystin-dependent calcium influx and nuclear export of histone deacetylase 5 (HDAC5), which facilitates the maintenance of renal epithelial architecture by de-repression of MEF2C target genes. Here, we screened a small-molecule library to find drugs that promotes nuclear export of HDAC5. We found that dopamine receptor antagonists, domperidone and loxapine succinate, stimulate export of HDAC5, even in Pkd1–/–cells. Domperidone targets Drd3 receptor to modulate the phosphorylation of HDAC5. Domperidone treatment increases HDAC5 phosphorylation likely by reducing protein phosphatase 2A (PP2A) activity, thus shifting the equilibrium towards HDAC5-P and export from the nucleus. Treating Pkd1–/–mice with domperidone showed significantly reduced cystic growth and cell proliferation. Further, treated mice displayed a reduction in glomerular cyst and increased body weight and activity. These results suggest that HDAC5 nucleocytoplasmic shuttling may be modulated to impede disease progression in ADPKD and uncovers an unexpected role for a class of dopamine receptors in renal epithelial morphogenesis.
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Affiliation(s)
- Parama Paul
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Stowers Institute for Medical Research, Kansas City, MO, United States
| | - Sreekumar Ramachandran
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Sheng Xia
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Stowers Institute for Medical Research, Kansas City, MO, United States
- Division of Neonatology, Children’s Mercy Hospital, Kansas City, MO, United States
| | - Jay R. Unruh
- Stowers Institute for Medical Research, Kansas City, MO, United States
| | | | - Rong Li
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Stowers Institute for Medical Research, Kansas City, MO, United States
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United States
- * E-mail:
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Sensory primary cilium is a responsive cAMP microdomain in renal epithelia. Sci Rep 2019; 9:6523. [PMID: 31024067 PMCID: PMC6484033 DOI: 10.1038/s41598-019-43002-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/12/2019] [Indexed: 02/07/2023] Open
Abstract
Primary cilia are hair-like cellular extensions that sense microenvironmental signals surrounding cells. The role of adenylyl cyclases in ciliary function has been of interest because the product of adenylyl cyclase activity, cAMP, is relevant to cilia-related diseases. In the present study, we show that vasopressin receptor type-2 (V2R) is localized to cilia in kidney epithelial cells. Pharmacologic inhibition of V2R with tolvaptan increases ciliary length and mechanosensory function. Genetic knockdown of V2R, however, does not have any effect on ciliary length, although the effect of tolvaptan on ciliary length is dampened. Our study reveals that tolvaptan may have a cilia-specific effect independent of V2R or verapamil-sensitive calcium channels. Live-imaging of single cilia shows that V2R activation increases cilioplasmic and cytoplasmic cAMP levels, whereas tolvaptan mediates cAMP changes only in a cilia-specific manner. Furthermore, fluid-shear stress decreases cilioplasmic, but not cytoplasmic cAMP levels. Our data indicate that cilioplasmic and cytoplasmic cAMP levels are differentially modulated. We propose that the cilium is a critical sensor acting as a responsive cAMP microcompartment during physiologically relevant stimuli.
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Pala R, Mohieldin AM, Sherpa RT, Kathem SH, Shamloo K, Luan Z, Zhou J, Zheng JG, Ahsan A, Nauli SM. Ciliotherapy: Remote Control of Primary Cilia Movement and Function by Magnetic Nanoparticles. ACS NANO 2019; 13:3555-3572. [PMID: 30860808 PMCID: PMC7899146 DOI: 10.1021/acsnano.9b00033] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Patients with polycystic kidney disease (PKD) are characterized with uncontrolled hypertension. Hypertension in PKD is a ciliopathy, an abnormal function and/or structure of primary cilia. Primary cilia are cellular organelles with chemo and mechanosensory roles. In the present studies, we designed a cilia-targeted (CT) delivery system to deliver fenoldopam specifically to the primary cilia. We devised the iron oxide nanoparticle (NP)-based technology for ciliotherapy. Live imaging confirmed that the CT-Fe2O3-NPs specifically targeted primary cilia in cultured cells in vitro and vascular endothelia in vivo. Importantly, the CT-Fe2O3-NPs enabled the remote control of the movement and function of a cilium with an external magnetic field, making the nonmotile cilium exhibit passive movement. The ciliopathic hearts displayed hypertrophy with compromised functions in left ventricle pressure, stroke volume, ejection fraction, and overall cardiac output because of prolonged hypertension. The CT-Fe2O3-NPs significantly improved cardiac function in the ciliopathic hypertensive models, in which the hearts also exhibited arrhythmia, which was corrected with the CT-Fe2O3-NPs. Intraciliary and cytosolic Ca2+ were increased when cilia were induced with fluid flow or magnetic field, and this served as a cilia-dependent mechanism of the CT-Fe2O3-NPs. Fenoldopam-alone caused an immediate decrease in blood pressure, followed by reflex tachycardia. Pharmacological delivery profiles confirmed that the CT-Fe2O3-NPs were a superior delivery system for targeting cilia more specifically, efficiently, and effectively than fenoldopam-alone. The CT-Fe2O3-NPs altered the mechanical properties of nonmotile cilia, and these nano-biomaterials had enormous clinical potential for ciliotherapy. Our studies further indicated that ciliotherapy provides a possibility toward personalized medicine in ciliopathy patients.
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Affiliation(s)
- Rajasekharreddy Pala
- Department of Biomedical & Pharmaceutical Sciences, Chapman University School of Pharmacy (CUSP), Harry and Diane Rinker Health Science Campus, Chapman University, Irvine, California 92618, United States
- Department of Medicine, University of California Irvine, Irvine, California 92868, United States
| | - Ashraf M. Mohieldin
- Department of Biomedical & Pharmaceutical Sciences, Chapman University School of Pharmacy (CUSP), Harry and Diane Rinker Health Science Campus, Chapman University, Irvine, California 92618, United States
- Department of Medicine, University of California Irvine, Irvine, California 92868, United States
| | - Rinzhin T. Sherpa
- Department of Biomedical & Pharmaceutical Sciences, Chapman University School of Pharmacy (CUSP), Harry and Diane Rinker Health Science Campus, Chapman University, Irvine, California 92618, United States
- Department of Medicine, University of California Irvine, Irvine, California 92868, United States
| | - Sarmed H. Kathem
- Department of Biomedical & Pharmaceutical Sciences, Chapman University School of Pharmacy (CUSP), Harry and Diane Rinker Health Science Campus, Chapman University, Irvine, California 92618, United States
- Department of Medicine, University of California Irvine, Irvine, California 92868, United States
| | - Kiumars Shamloo
- Department of Biomedical & Pharmaceutical Sciences, Chapman University School of Pharmacy (CUSP), Harry and Diane Rinker Health Science Campus, Chapman University, Irvine, California 92618, United States
- Department of Medicine, University of California Irvine, Irvine, California 92868, United States
| | - Zhongyue Luan
- Chemical Engineering & Material Sciences, University of California Irvine, Irvine, California 92697, United States
| | - Jing Zhou
- Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Jian-Guo Zheng
- Irvine Materials Research Institute, University of California Irvine, Irvine, California 92697, United States
| | - Amir Ahsan
- Department of Physics, Computer Science & Engineering, Chapman University, Orange, California 92866, United States
| | - Surya M. Nauli
- Department of Biomedical & Pharmaceutical Sciences, Chapman University School of Pharmacy (CUSP), Harry and Diane Rinker Health Science Campus, Chapman University, Irvine, California 92618, United States
- Department of Medicine, University of California Irvine, Irvine, California 92868, United States
- Corresponding Author: ; . (S.M.N.)
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Saito M, Sato T. [Current situation of researches on a sensor organelle, primary cilium, to understand the pathogenesis of ciliopathy]. Nihon Yakurigaku Zasshi 2019; 153:117-123. [PMID: 30867380 DOI: 10.1254/fpj.153.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Primary cilium is a membrane-protruding immotile sensory organelle. It had been supposed that the cilium was a static organelle for long periods. However, recent studies have uncovered that the cilium is dynamically organized organelle in a cell cycle-dependent manner; it is formed during G0/G1 phase and resorbed when the cells enter cell division cycle. Despite the primary cilium is very short and its surface area is extremely small, the cilium possesses a few kinds of G protein-coupled receptors, growth factor receptors and ion channels. Therefore, it can function as a signaling receptor for selective bioactive ligands and mechanical stresses. Dysregulation of the ciliary dynamics is linked with hereditary disorders, so called "ciliopathy", with clinical manifestations of microcephaly, polycystic kidney, situs inversus, polydactyly, and so on. No effective medical treatment for the ciliopathies has been available. Increasing evidences about the molecular mechanisms of ciliary dynamics and ciliary functions have revealed that enormous number of molecules regulate a cycle of ciliogenesis, cilium-derived signaling, ciliary resorption and elimination. However, it is a fact that research progress is far inferior to the full disclosure of the molecular mechanisms. Further studies are required to clarify the pathogenesis of the cilipathies. Moreover, efficient medical treatments are expected to be developed by pharmacological approaches.
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Affiliation(s)
- Masaki Saito
- Department of Molecular Pharmacology, Tohoku University School of Medicine
| | - Takeya Sato
- Department of Molecular Pharmacology, Tohoku University School of Medicine
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The Roles of Primary Cilia in Cardiovascular Diseases. Cells 2018; 7:cells7120233. [PMID: 30486394 PMCID: PMC6315816 DOI: 10.3390/cells7120233] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 11/21/2018] [Accepted: 11/23/2018] [Indexed: 02/07/2023] Open
Abstract
Primary cilia are microtubule-based organelles found in most mammalian cell types. Cilia act as sensory organelles that transmit extracellular clues into intracellular signals for molecular and cellular responses. Biochemical and molecular defects in primary cilia are associated with a wide range of diseases, termed ciliopathies, with phenotypes ranging from polycystic kidney disease, liver disorders, mental retardation, and obesity to cardiovascular diseases. Primary cilia in vascular endothelia protrude into the lumen of blood vessels and function as molecular switches for calcium (Ca2+) and nitric oxide (NO) signaling. As mechanosensory organelles, endothelial cilia are involved in blood flow sensing. Dysfunction in endothelial cilia contributes to aberrant fluid-sensing and thus results in vascular disorders, including hypertension, aneurysm, and atherosclerosis. This review focuses on the most recent findings on the roles of endothelial primary cilia within vascular biology and alludes to the possibility of primary cilium as a therapeutic target for cardiovascular disorders.
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Ciliotherapy Treatments to Enhance Biochemically- and Biophysically-Induced Mesenchymal Stem Cell Osteogenesis: A Comparison Study. Cell Mol Bioeng 2018; 12:53-67. [PMID: 31719899 DOI: 10.1007/s12195-018-00561-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/07/2018] [Indexed: 01/12/2023] Open
Abstract
Introduction New approaches to treat osteoporosis have focused on promoting bone formation through the targeting of osteoblasts and their progenitors, mesenchymal stem cells (MSCs). The primary cilium is a singular cellular extension known to play an important role in biochemical and biophysical osteogenic induction of MSCs. Defects in ciliary structure have been associated with a plethora of diseases. Therefore targeting the cilium therapeutically (ciliotherapies) has emerged as a potential new treatment modality. Therefore, this study performed a comparison analysis on known ciliotherapies and their potential effects in mediating MSC osteogenic differentiation. Methods MSCs were treated with forskolin, lithium chloride (LiCl) or fenoldopam to investigate the effect on ciliogenesis and cilia-associated signalling. Moreover, both early and long term biochemical and biophysical (fluid shear) induced osteogenic differentiation was examined in terms of osteogenic gene expression and bone matrix deposition following each treatment. Results LiCl and fenoldopam were found to enhance MSC ciliogenesis to a similar degree. LiCl significantly altered hedgehog (HH) and Wnt signalling which was associated with inhibited osteogenic gene expression, while fenoldopam demonstrated enhanced early osteogenesis. Long term treatment with both ciliotherapies did not enhance osteogenesis, however LiCl had detrimental effects on cell viability. Intriguingly both ciliotherapies enhanced MSC mechanosensitivity as demonstrated by augmented osteogenic gene expression in response to fluid shear, which over longer durations resulted in enhanced matrix deposition per cell. Conclusions Therefore, ciliotherapies can be utilised to enhance MSC ciliogenesis resulting in enhanced mechanosensitivity, however, only fenoldopam is a viable ciliotherapeutic option to enhance MSC osteogenesis.
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Saternos HC, AbouAlaiwi WA. Signaling interplay between primary cilia and nitric oxide: A mini review. Nitric Oxide 2018; 80:108-112. [PMID: 30099097 DOI: 10.1016/j.niox.2018.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/01/2018] [Accepted: 08/06/2018] [Indexed: 01/12/2023]
Abstract
New discoveries into the functional role of primary cilia are on the rise. In little more than 20 years, research has shown the once vestigial organelle is a signaling powerhouse involved in a vast number of essential cellular processes. In the same decade that interest in primary cilia was burgeoning, nitric oxide won molecule of the year and a Nobel prize for its role as a near ubiquitous signaling molecule. Although primary cilia and nitric oxide are both involved in signaling, a direct relationship has not been investigated; however, after a quick review of the literature, parallels between their functions can be drawn. This review aims to suggest a possible interplay between primary cilia and nitric oxide signaling especially in the areas of vascular tissue homeostasis and cellular proliferation.
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Affiliation(s)
- Hannah C Saternos
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, USA
| | - Wissam A AbouAlaiwi
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, USA.
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Abstract
PURPOSE OF REVIEW Primary cilia have become important organelles implicated in embryonic development, organogenesis, health, and diseases. Although many studies in cell biology have focused on changes in ciliary length or ciliogenesis, the most common readout for evaluating ciliary function is intracellular calcium. RECENT FINDINGS Recent tools have allowed us to examine intracellular calcium in more precise locations, that is, the cilioplasm and cytoplasm. Advances in calcium imaging have also allowed us to identify which cilia respond to particular stimuli. Furthermore, direct electrophysiological measurement of ionic currents within a cilium has provided a wealth of information for understanding the sensory roles of primary cilia. SUMMARY Calcium imaging and direct measurement of calcium currents demonstrate that primary cilia are sensory organelles that house several types of functional calcium channels. Although intracellular calcium now allows a functional readout for primary cilia, discussions on the relative contributions of the several channel types have just begun. Perhaps, all of these calcium channels are required and necessary to differentiate stimuli in different microenvironments.
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Primary Cilium-Dependent Signaling Mechanisms. Int J Mol Sci 2017; 18:ijms18112272. [PMID: 29143784 PMCID: PMC5713242 DOI: 10.3390/ijms18112272] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/13/2017] [Accepted: 10/25/2017] [Indexed: 01/02/2023] Open
Abstract
Primary cilia are hair-like organelles and play crucial roles in vertebrate development, organogenesis, health, and many genetic disorders. A primary cilium is a mechano-sensory organelle that responds to mechanical stimuli in the micro-environment. A cilium is also a chemosensor that senses chemical signals surrounding a cell. The overall function of a cilium is therefore to act as a communication hub to transfer extracellular signals into intracellular responses. Although intracellular calcium has been one of the most studied signaling messengers that transmit extracellular signals into the cells, calcium signaling by various ion channels remains a topic of interest in the field. This may be due to a broad spectrum of cilia functions that are dependent on or independent of utilizing calcium as a second messenger. We therefore revisit and discuss the calcium-dependent and calcium-independent ciliary signaling pathways of Hedgehog, Wnt, PDGFR, Notch, TGF-β, mTOR, OFD1 autophagy, and other GPCR-associated signaling. All of these signaling pathways play crucial roles in various cellular processes, such as in organ and embryonic development, cardiac functioning, planar cell polarity, transactivation, differentiation, the cell cycle, apoptosis, tissue homeostasis, and the immune response.
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Shamloo K, Chen J, Sardar J, Sherpa RT, Pala R, Atkinson KF, Pearce WJ, Zhang L, Nauli SM. Chronic Hypobaric Hypoxia Modulates Primary Cilia Differently in Adult and Fetal Ovine Kidneys. Front Physiol 2017; 8:677. [PMID: 28979210 PMCID: PMC5611369 DOI: 10.3389/fphys.2017.00677] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/24/2017] [Indexed: 11/13/2022] Open
Abstract
Hypoxic environments at high altitude have significant effects on kidney injury. Following injury, renal primary cilia display length alterations. Primary cilia are mechanosensory organelles that regulate tubular architecture. The effect of hypoxia on cilia length is still controversial in cultured cells, and no corresponding in vivo study exists. Using fetal and adult sheep, we here study the effect of chronic hypobaric hypoxia on the renal injury, intracellular calcium signaling and the relationship between cilia length and cilia function. Our results show that although long-term hypoxia induces renal fibrosis in both fetal and adult kidneys, fetal kidneys are more susceptible to hypoxia-induced renal injury. Unlike hypoxic adult kidneys, hypoxic fetal kidneys are characterized by interstitial edema, tubular disparition and atrophy. We also noted that there is an increase in the cilia length as well as an increase in the cilia function in the hypoxic fetal proximal and distal collecting epithelia. Hypoxia, however, has no significant effect on primary cilia in the adult kidneys. Increased cilia length is also associated with greater flow-induced intracellular calcium signaling in renal epithelial cells from hypoxic fetuses. Our studies suggest that while hypoxia causes renal fibrosis in both adult and fetal kidneys, hypoxia-induced alteration in cilia length and function are specific to more severe renal injuries in fetal hypoxic kidneys.
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Affiliation(s)
- Kiumars Shamloo
- Department of Biomedical and Pharmaceutical Sciences, Chapman UniversityIrvine, CA, United States
| | - Juan Chen
- Department of Biomedical and Pharmaceutical Sciences, Chapman UniversityIrvine, CA, United States
| | - Jasmine Sardar
- Department of Biomedical and Pharmaceutical Sciences, Chapman UniversityIrvine, CA, United States
| | - Rinzhin T Sherpa
- Department of Biomedical and Pharmaceutical Sciences, Chapman UniversityIrvine, CA, United States
| | - Rajasekharreddy Pala
- Department of Biomedical and Pharmaceutical Sciences, Chapman UniversityIrvine, CA, United States
| | - Kimberly F Atkinson
- Department of Biomedical and Pharmaceutical Sciences, Chapman UniversityIrvine, CA, United States
| | - William J Pearce
- Departments of Basic Sciences, Physiology and Pharmacology, Lawrence D. Longo MD Center for Perinatal Biology, Loma Linda University School of MedicineLoma Linda, CA, United States
| | - Lubo Zhang
- Departments of Basic Sciences, Physiology and Pharmacology, Lawrence D. Longo MD Center for Perinatal Biology, Loma Linda University School of MedicineLoma Linda, CA, United States
| | - Surya M Nauli
- Department of Biomedical and Pharmaceutical Sciences, Chapman UniversityIrvine, CA, United States.,Division of Nephrology and Hypertension, Department of Medicine, University of California, IrvineIrvine, CA, United States
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Mykytyn K, Askwith C. G-Protein-Coupled Receptor Signaling in Cilia. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a028183. [PMID: 28159877 DOI: 10.1101/cshperspect.a028183] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
G-protein-coupled receptors (GPCRs) are the largest and most versatile family of signaling receptors in humans. They respond to diverse external signals, such as photons, proteins, peptides, chemicals, hormones, lipids, and sugars, and mediate a myriad of functions in the human body. Signaling through GPCRs can be optimized by enriching receptors and downstream effectors in discrete cellular domains. Many GPCRs have been found to be selectively targeted to cilia on numerous mammalian cell types. Moreover, investigations into the pathophysiology of human ciliopathies have implicated GPCR ciliary signaling in a number of developmental and cellular pathways. Thus, cilia are now appreciated as an increasingly important nexus for GPCR signaling. Yet, we are just beginning to understand the precise signaling pathways mediated by most ciliary GPCRs and how they impact cellular function and mammalian physiology.
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Affiliation(s)
- Kirk Mykytyn
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Ohio 43210.,Neuroscience Research Institute, The Ohio State University, Ohio 43210
| | - Candice Askwith
- Neuroscience Research Institute, The Ohio State University, Ohio 43210.,Department of Neuroscience, The Ohio State University, Ohio 43210
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28
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Takao D, Kamimura S. Simulation of intra-ciliary diffusion suggests a novel role of primary cilia as a cell-signaling enhancer. Dev Growth Differ 2017; 59:415-422. [PMID: 28573753 DOI: 10.1111/dgd.12360] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 12/16/2022]
Abstract
Besides the role to generate a fluid flow in the surrounding medium, eukaryotic cilia have a crucial function in sensing external signals such as chemical or mechanical stimuli. A large body of work has shown that cilia are frequently found in various types of sensory cells and are closely related to many regulatory mechanisms in differentiation and development. However, we do not yet have a definitive answer to the fundamental question, "why cilia?" It has been a long-standing mystery why cells use cilia for sensing external signals. To shed light on this, we sought to describe the kinetics of signaling with theoretical approaches. Based on the results, here we propose a new role of cilia as a cell-signaling enhancer. The enhancing effect comes from restricted volume for the free intra-ciliary diffusion of molecules due to the cylindrical shape of cilia, which can facilitate quick accumulation of intracellular signaling molecules. Our simulations demonstrate that both the rate and amplitude of response in signal transduction depend on where the membrane receptors or channels are located along the ciliary shaft. In addition, the calculated transfer function of cilia regarded as a transmitter of external signals also suggests the properties of cilia as a signal enhancer. Since such unique composition of receptors and channels in cilia is found in various types of eukaryotic cells, signal enhancing is presumably one of the most essential and conserved roles of cilia.
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Affiliation(s)
- Daisuke Takao
- Department of Molecular Genetics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Shinji Kamimura
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
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29
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Abstract
The primary cilium is a mechanosensor in a variety of mammalian cell types, initiating and directing intracellular signalling cascades in response to external stimuli. When primary cilia formation is disrupted, cells have diminished mechanosensitivity and an abrogated response to mechanical stimulation. Due to this important role, we hypothesised that increasing primary cilia length would enhance the downstream response and therefore, mechanosensitivity. To test this hypothesis, we increased osteocyte primary cilia length with fenoldopam and lithium and found that cells with longer primary cilia were more mechanosensitive. Furthermore, fenoldopam treatment potentiated adenylyl cyclase activity and was able to recover primary cilia form and sensitivity in cells with impaired cilia. This work demonstrates that modulating the structure of the primary cilium directly impacts cellular mechanosensitivity. Our results implicate cilium length as a potential therapeutic target for combating numerous conditions characterised by impaired cilia function.
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30
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Abstract
Primary cilia are small, antenna-like structures that detect mechanical and chemical cues and transduce extracellular signals. While mammalian primary cilia were first reported in the late 1800s, scientific interest in these sensory organelles has burgeoned since the beginning of the twenty-first century with recognition that primary cilia are essential to human health. Among the most common clinical manifestations of ciliary dysfunction are renal cysts. The molecular mechanisms underlying renal cystogenesis are complex, involving multiple aberrant cellular processes and signaling pathways, while initiating molecular events remain undefined. Autosomal Dominant Polycystic Kidney Disease is the most common renal cystic disease, caused by disruption of polycystin-1 and polycystin-2 transmembrane proteins, which evidence suggests must localize to primary cilia for proper function. To understand how the absence of these proteins in primary cilia may be remediated, we review intracellular trafficking of polycystins to the primary cilium. We also examine the controversial mechanisms by which primary cilia transduce flow-mediated mechanical stress into intracellular calcium. Further, to better understand ciliary function in the kidney, we highlight the LKB1/AMPK, Wnt, and Hedgehog developmental signaling pathways mediated by primary cilia and misregulated in renal cystic disease.
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31
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Sherpa RT, Atkinson KF, Ferreira VP, Nauli SM. RAPAMYCIN INCREASES LENGTH AND MECHANOSENSORY FUNCTION OF PRIMARY CILIA IN RENAL EPITHELIAL AND VASCULAR ENDOTHELIAL CELLS. INTERNATIONAL EDUCATION AND RESEARCH JOURNAL 2016; 2:91-97. [PMID: 28529994 PMCID: PMC5436805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Primary cilia arebiophysically-sensitive organelles responsible for sensing fluid-flow and transducing this stimulus into intracellular responses. Previous studies have shown that the primary cilia mediate flow-induced calcium influx, and sensitivity of cilia function to flow is correlated to cilia length. Cells with abnormal cilia length or function can lead to a host of diseases that are collectively termed as ciliopathies. Rapamycin, a potent inhibitor of mTOR (mammalian target of rapamycin), has been demonstrated to be a potential pharmacological agent against the aberrant mTOR signaling seen in ciliopathies such as polycystic kidney disease (PKD) and tuberous sclerosis complex (TSC). Here we look at the effects of rapamycin on ciliary length and function for the first time. Compared to controls, primary cilia in rapamycin-treated porcine renal epithelial and mouse vascular endothelial cells showed a significant increase in length. Graded increases in fluid-shear stress further indicates that rapamycin enhances cilia sensitivity to fluid flow. Treatment with rapamycin led to G0 arrest in porcine epithelial cells while no significant change in cell cycle were observed in rapamycin-treated mouse epithelial or endothelial cells, indicating a species-specific effect of rapamycin. Given the previousin vitro and in vivo studies establishing rapamycin as a potential therapeutic agent for ciliopathies, such as PKD and TSC, our studies show that rapamycin enhances ciliary function and sensitivity to fluid flow. The results of our studies suggest a potential ciliotherapeutic effect of rapamycin.
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Affiliation(s)
- Rinzhin T. Sherpa
- Department of Biomedical & Pharmaceutical Sciences, Chapman University, Irvine, CA
| | - Kimberly F. Atkinson
- Department of Biomedical & Pharmaceutical Sciences, Chapman University, Irvine, CA
| | - Viviana P. Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH
| | - Surya M. Nauli
- Department of Biomedical & Pharmaceutical Sciences, Chapman University, Irvine, CA
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32
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Han SJ, Jang HS, Kim JI, Lipschutz JH, Park KM. Unilateral nephrectomy elongates primary cilia in the remaining kidney via reactive oxygen species. Sci Rep 2016; 6:22281. [PMID: 26923764 PMCID: PMC4770282 DOI: 10.1038/srep22281] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 02/10/2016] [Indexed: 12/15/2022] Open
Abstract
The length of primary cilia is associated with normal cell and organ function. In the kidney, the change of functional cilia length/mass is associated with various diseases such as ischemia/reperfusion injury, polycystic kidney disease, and congenital solitary kidney. Here, we investigate whether renal mass reduction affects primary cilia length and function. To induce renal mass reduction, mice were subjected to unilateral nephrectomy (UNx). UNx increased kidney weight and superoxide formation in the remaining kidney. Primary cilia were elongated in proximal tubule cells, collecting duct cells and parietal cells of the remaining kidney. Mn(III) Tetrakis (1-methyl-4-pyridyl) porphyrin (MnTMPyP), an antioxidant, reduced superoxide formation in UNx-mice and prevented the elongation of primary cilia. UNx increased the expression of phosphorylated ERK, p21, and exocyst complex members Sec8 and Sec10, in the remaining kidney, and these increases were prevented by MnTMPyP. In MDCK, a kidney tubular epithelial cell line, cells, low concentrations of H2O2 treatment elongated primary cilia. This H2O2-induced elongation of primary cilia was also prevented by MnTMPyP treatment. Taken together, these data demonstrate that kidney compensation, induced by a reduction of renal mass, results in primary cilia elongation, and this elongation is associated with an increased production of reactive oxygen species (ROS).
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Affiliation(s)
- Sang Jun Han
- Department of Anatomy and BK 21 Project, Kyungpook National University School of Medicine, Daegu 700-422, Republic of Korea
| | - Hee-Seong Jang
- Department of Anatomy and BK 21 Project, Kyungpook National University School of Medicine, Daegu 700-422, Republic of Korea
| | - Jee In Kim
- Department of Molecular Medicine and MRC, Keimyung University School of Medicine, Daegu 705-717, Republic of Korea
| | - Joshua H Lipschutz
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA.,Department of Medicine, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina, USA
| | - Kwon Moo Park
- Department of Anatomy and BK 21 Project, Kyungpook National University School of Medicine, Daegu 700-422, Republic of Korea
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33
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Abstract
PURPOSE OF REVIEW This review will highlight recent findings concerning the regulation and signalling of the intrarenal dopaminergic system and the emerging evidence for its importance in blood pressure regulation. RECENT FINDINGS There is an increasing evidence that the intrarenal dopaminergic system plays an important role in the regulation of blood pressure, and defects in dopamine signalling appear to be involved in the development of hypertension. Recent experimental models have definitively demonstrated that abnormalities in intrarenal dopamine production or receptor signalling can predispose to salt-sensitive hypertension and a dysregulated renin-angiotensin system. There are also new results indicating the importance of dopamine receptor mediated regulation of salt and water homeostasis along the nephron, and new studies indicating the role that the intrarenal dopaminergic system plays to mitigate the production of reactive oxygen species and progression of chronic renal disease. SUMMARY New studies underscore the importance of the intrarenal dopaminergic system in the regulation of renal function and indicate how alterations in dopamine production or signalling may underlie the development of hypertension and kidney injury.
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34
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Schou KB, Pedersen LB, Christensen ST. Ins and outs of GPCR signaling in primary cilia. EMBO Rep 2015; 16:1099-113. [PMID: 26297609 DOI: 10.15252/embr.201540530] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 07/01/2015] [Indexed: 12/17/2022] Open
Abstract
Primary cilia are specialized microtubule-based signaling organelles that convey extracellular signals into a cellular response in most vertebrate cell types. The physiological significance of primary cilia is underscored by the fact that defects in assembly or function of these organelles lead to a range of severe diseases and developmental disorders. In most cell types of the human body, signaling by primary cilia involves different G protein-coupled receptors (GPCRs), which transmit specific signals to the cell through G proteins to regulate diverse cellular and physiological events. Here, we provide an overview of GPCR signaling in primary cilia, with main focus on the rhodopsin-like (class A) and the smoothened/frizzled (class F) GPCRs. We describe how such receptors dynamically traffic into and out of the ciliary compartment and how they interact with other classes of ciliary GPCRs, such as class B receptors, to control ciliary function and various physiological and behavioral processes. Finally, we discuss future avenues for developing GPCR-targeted drug strategies for the treatment of ciliopathies.
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35
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Atkinson KF, Kathem SH, Jin X, Muntean BS, Abou-Alaiwi WA, Nauli AM, Nauli SM. Dopaminergic signaling within the primary cilia in the renovascular system. Front Physiol 2015; 6:103. [PMID: 25932013 PMCID: PMC4399208 DOI: 10.3389/fphys.2015.00103] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 03/13/2015] [Indexed: 12/15/2022] Open
Abstract
Activation of dopamine receptor type-5 (DR5) has been known to reduce systemic blood pressure, most likely by increasing renal vasodilation and enhancing natriuresis in the kidney. However, the mechanism of DR5 in natriuresis and vasodilation was not clearly known. We have previously shown that DR5 is localized to primary cilia of proximal renal epithelial and vascular endothelial cells. We here show that selective activation of DR5 specifically induces calcium influx only in the primary cilia, whereas non-selective activation of dopamine receptor induces calcium fluxes in both cilioplasm and cytoplasm. Cilia-independent signaling induced by thrombin only shows calcium signaling within cytoplasm. Furthermore, calcium activation in the cilioplasm by DR5 increases length and mechanosensory function of primary cilia, leading to a greater response to fluid-shear stress. We therefore propose a new mechanism by which DR5 induces vasodilation via chemical and mechanical properties that are specific to primary cilia.
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Affiliation(s)
- Kimberly F Atkinson
- Department of Biomedical and Pharmaceutical Sciences, Chapman University Irvine, CA, USA
| | - Sarmed H Kathem
- Department of Biomedical and Pharmaceutical Sciences, Chapman University Irvine, CA, USA
| | - Xingjian Jin
- Department of Pharmacology and Experimental Therapeutics, University of Toledo Toledo, OH, USA
| | - Brian S Muntean
- Department of Pharmacology and Experimental Therapeutics, University of Toledo Toledo, OH, USA
| | - Wissam A Abou-Alaiwi
- Department of Pharmacology and Experimental Therapeutics, University of Toledo Toledo, OH, USA
| | - Andromeda M Nauli
- Department of Pharmaceutical and Biomedical Sciences, California Northstate University Elk Grove, CA, USA
| | - Surya M Nauli
- Department of Biomedical and Pharmaceutical Sciences, Chapman University Irvine, CA, USA
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