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Grainger N. Identifying peristaltic pacemaker cells in the upper urinary tract. J Physiol 2024. [PMID: 38180778 DOI: 10.1113/jp284754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Accepted: 12/18/2023] [Indexed: 01/06/2024] Open
Abstract
Urine expulsion from the upper urinary tract is a necessary process that eliminates waste, promotes renal filtration and prevents nephron damage. To facilitate the movement of urine boluses throughout the upper urinary tract, smooth muscle cells that line the renal pelvis contract in a coordinated effort to form peristaltic waves. Resident pacemaker cells in the renal pelvis are critical to this process and spontaneously evoke transient depolarizations that initiate each peristaltic wave and establish rhythmic contractions. Renal pacemakers have been termed atypical smooth muscle cells due to their low expression of smooth muscle myosin and poor organization of myofilaments compared to typical (or contractile) smooth muscle cells that perform peristalsis. Recent findings discovered that pacemaker cells also express the tyrosine kinase receptor PDGFRα, enabling their identification and purification amongst other renal pelvis cell types. Improved identification methods have determined that the calcium-activated chloride channel, ANO1, is expressed by pacemaker cells and may contribute to spontaneous depolarization. A greater understanding of pacemaker and peristaltic mechanisms is warranted since aberrant contractile function may underlie diseases such as hydronephrosis, a deleterious condition that can cause significant and irreversible nephron injury.
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Affiliation(s)
- Nathan Grainger
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA
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2
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Grainger N, Shonnard CC, Quiggle SK, Fox EB, Presley H, Daugherty R, Shonnard MC, Drumm BT, Sanders KM. Propagation of Pacemaker Activity and Peristaltic Contractions in the Mouse Renal Pelvis Rely on Ca 2+-activated Cl - Channels and T-Type Ca 2+ Channels. FUNCTION (OXFORD, ENGLAND) 2022; 3:zqac041. [PMID: 36325511 PMCID: PMC9614935 DOI: 10.1093/function/zqac041] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 08/15/2022] [Accepted: 08/16/2022] [Indexed: 01/07/2023]
Abstract
The process of urine removal from the kidney occurs via the renal pelvis (RP). The RP demarcates the beginning of the upper urinary tract and is endowed with smooth muscle cells. Along the RP, organized contraction of smooth muscle cells generates the force required to move urine boluses toward the ureters and bladder. This process is mediated by specialized pacemaker cells that are highly expressed in the proximal RP that generate spontaneous rhythmic electrical activity to drive smooth muscle depolarization. The mechanisms by which peristaltic contractions propagate from the proximal to distal RP are not fully understood. In this study, we utilized a transgenic mouse that expresses the genetically encoded Ca2+ indicator, GCaMP3, under a myosin heavy chain promotor to visualize spreading peristaltic contractions in high spatial detail. Using this approach, we discovered variable effects of L-type Ca2+ channel antagonists on contraction parameters. Inhibition of T-type Ca2+ channels reduced the frequency and propagation distance of contractions. Similarly, antagonizing Ca2+-activated Cl- channels or altering the transmembrane Cl- gradient decreased contractile frequency and significantly inhibited peristaltic propagation. These data suggest that voltage-gated Ca2+ channels are important determinants of contraction initiation and maintain the fidelity of peristalsis as the spreading contraction moves further toward the ureter. Recruitment of Ca2+-activated Cl- channels, likely Anoctamin-1, and T-type Ca2+ channels are required for efficiently conducting the depolarizing current throughout the length of the RP. These mechanisms are necessary for the efficient removal of urine from the kidney.
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Affiliation(s)
| | - Cameron C Shonnard
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Sage K Quiggle
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Emily B Fox
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Hannah Presley
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Robbie Daugherty
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Matthew C Shonnard
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA,Department of Life and Health Science, Dundalk Institute of Technology, Dublin Road, Dundalk, Co. Louth, A91 K584, Ireland
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
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Yoshikawa M, Mitsui R, Takano H, Hashitani H. Mechanosensitive modulation of peristaltic contractions in the mouse renal pelvis. Eur J Pharmacol 2022; 920:174834. [DOI: 10.1016/j.ejphar.2022.174834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 02/02/2022] [Accepted: 02/15/2022] [Indexed: 11/16/2022]
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Sallam M, Palakkan AA, Mills CG, Tarnick J, Elhendawi M, Marson L, Davies JA. Differentiation of a Contractile, Ureter-Like Tissue, from Embryonic Stem Cell-Derived Ureteric Bud and Ex Fetu Mesenchyme. J Am Soc Nephrol 2020; 31:2253-2262. [PMID: 32826325 DOI: 10.1681/asn.2019101075] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 06/11/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND There is intense interest in replacing kidneys from stem cells. It is now possible to produce, from embryonic or induced pluripotent stem cells, kidney organoids that represent immature kidneys and display some physiologic functions. However, current techniques have not yet resulted in renal tissue with a ureter, which would be needed for engineered kidneys to be clinically useful. METHODS We used a published sequence of growth factors and drugs to induce mouse embryonic stem cells to differentiate into ureteric bud tissue. We characterized isolated engineered ureteric buds differentiated from embryonic stem cells in three-dimensional culture and grafted them into ex fetu mouse kidney rudiments. RESULTS Engineered ureteric buds branched in three-dimensional culture and expressed Hoxb7, a transcription factor that is part of a developmental regulatory system and a ureteric bud marker. When grafted into the cortex of ex fetu kidney rudiments, engineered ureteric buds branched and induced nephron formation; when grafted into peri-Wolffian mesenchyme, still attached to a kidney rudiment or in isolation, they did not branch but instead differentiated into multilayer ureter-like epithelia displaying robust expression of the urothelial marker uroplakin. This engineered ureteric bud tissue also organized the mesenchyme into smooth muscle that spontaneously contracted, with a period a little slower than that of natural ureteric peristalsis. CONCLUSIONS Mouse embryonic stem cells can be differentiated into ureteric bud cells. Grafting those UB-like structures into peri-Wolffian mesenchyme of cultured kidney rudiments can induce production of urothelium and organize the mesenchyme to produce rhythmically contracting smooth muscle layers. This development may represent a significant step toward the goal of renal regeneration.
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Affiliation(s)
- May Sallam
- Deanery of Biomedical Science, University of Edinburgh, Edinburgh, UK .,Human Anatomy and Embryology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Anwar A Palakkan
- Deanery of Biomedical Science, University of Edinburgh, Edinburgh, UK
| | | | - Julia Tarnick
- Deanery of Biomedical Science, University of Edinburgh, Edinburgh, UK
| | - Mona Elhendawi
- Deanery of Biomedical Science, University of Edinburgh, Edinburgh, UK.,Clinical Pathology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Lorna Marson
- Edinburgh Transplant Centre, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - Jamie A Davies
- Deanery of Biomedical Science, University of Edinburgh, Edinburgh, UK
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Lang RJ, Hashitani H. Pacemaker Mechanisms Driving Pyeloureteric Peristalsis: Modulatory Role of Interstitial Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:77-101. [PMID: 31183823 DOI: 10.1007/978-981-13-5895-1_3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The peristaltic pressure waves in the renal pelvis that propel urine expressed by the kidney into the ureter towards the bladder have long been considered to be 'myogenic', being little affected by blockers of nerve conduction or autonomic neurotransmission, but sustained by the intrinsic release of prostaglandins and sensory neurotransmitters. In uni-papilla mammals, the funnel-shaped renal pelvis consists of a lumen-forming urothelium and a stromal layer enveloped by a plexus of 'typical' smooth muscle cells (TSMCs), in multi-papillae kidneys a number of minor and major calyces fuse into a large renal pelvis. Electron microscopic, electrophysiological and Ca2+ imaging studies have established that the pacemaker cells driving pyeloureteric peristalsis are likely to be morphologically distinct 'atypical' smooth muscle cells (ASMCs) that fire Ca2+ transients and spontaneous transient depolarizations (STDs) which trigger propagating nifedipine-sensitive action potentials and Ca2+ waves in the TSMC layer. In uni-calyceal kidneys, ASMCs predominately locate on the serosal surface of the proximal renal pelvis while in multi-papillae kidneys they locate within the sub-urothelial space. 'Fibroblast-like' interstitial cells (ICs) located in the sub-urothelial space or adventitia are a mixed population of cells, having regional and species-dependent expression of various Cl-, K+, Ca2+ and cationic channels. ICs display asynchronous Ca2+ transients that periodically synchronize into bursts that accelerate ASMC Ca2+ transient firing. This review presents current knowledge of the architecture of the proximal renal pelvis, the role Ca2+ plays in renal pelvis peristalsis and the mechanisms by which ICs may sustain/accelerate ASMC pacemaking.
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Affiliation(s)
- Richard J Lang
- School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia.
| | - Hikaru Hashitani
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
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Radu BM, Banciu A, Banciu DD, Radu M, Cretoiu D, Cretoiu SM. Calcium Signaling in Interstitial Cells: Focus on Telocytes. Int J Mol Sci 2017; 18:ijms18020397. [PMID: 28208829 PMCID: PMC5343932 DOI: 10.3390/ijms18020397] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/04/2017] [Accepted: 01/25/2017] [Indexed: 02/08/2023] Open
Abstract
In this review, we describe the current knowledge on calcium signaling pathways in interstitial cells with a special focus on interstitial cells of Cajal (ICCs), interstitial Cajal-like cells (ICLCs), and telocytes. In detail, we present the generation of Ca2+ oscillations, the inositol triphosphate (IP3)/Ca2+ signaling pathway and modulation exerted by cytokines and vasoactive agents on calcium signaling in interstitial cells. We discuss the physiology and alterations of calcium signaling in interstitial cells, and in particular in telocytes. We describe the physiological contribution of calcium signaling in interstitial cells to the pacemaking activity (e.g., intestinal, urinary, uterine or vascular pacemaking activity) and to the reproductive function. We also present the pathological contribution of calcium signaling in interstitial cells to the aortic valve calcification or intestinal inflammation. Moreover, we summarize the current knowledge of the role played by calcium signaling in telocytes in the uterine, cardiac and urinary physiology, and also in various pathologies, including immune response, uterine and cardiac pathologies.
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Affiliation(s)
- Beatrice Mihaela Radu
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona 37134, Italy.
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest 050095, Romania.
| | - Adela Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest 050095, Romania.
- Research Beyond Limits, Dimitrie Cantemir 15, Bucharest 040234, Romania.
- Engineering Faculty, Constantin Brancusi University, Calea Eroilor 30, Targu Jiu 210135, Romania.
| | - Daniel Dumitru Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest 050095, Romania.
- Research Beyond Limits, Dimitrie Cantemir 15, Bucharest 040234, Romania.
| | - Mihai Radu
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona 37134, Italy.
- Department of Life and Environmental Physics, Horia Hulubei National Institute of Physics and Nuclear Engineering, Reactorului 30, P.O. Box MG-6, Magurele 077125, Romania.
| | - Dragos Cretoiu
- Division of Cell Biology and Histology, Carol Davila University of Medicine and Pharmacy, Bucharest 050474, Romania.
- Victor Babes National Institute of Pathology, Bucharest 050096, Romania.
| | - Sanda Maria Cretoiu
- Division of Cell Biology and Histology, Carol Davila University of Medicine and Pharmacy, Bucharest 050474, Romania.
- Victor Babes National Institute of Pathology, Bucharest 050096, Romania.
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Janssen C, Buttyan R, Seow CY, Jäger W, Solomon D, Fazli L, Chew BH, Lange D. A Role for the Hedgehog Effector Gli1 in Mediating Stent-induced Ureteral Smooth Muscle Dysfunction and Aperistalsis. Urology 2017; 104:242.e1-242.e8. [PMID: 28188758 DOI: 10.1016/j.urology.2017.01.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 09/05/2016] [Accepted: 01/24/2017] [Indexed: 01/17/2023]
Abstract
OBJECTIVE To better understand the effects of double J stenting on ureteral physiology and function. MATERIALS AND METHODS In total, 24 pigs were stented cystoscopically unilaterally for 48 hours, 1, 2, 4, and 7 weeks. Controls consisted of un-stented animals (n = 4) or the contralateral un-stented ureter in pigs. Ureters were harvested and tested in tissue baths to evaluate their contractility. Ureteral inflammation and expression of Sonic Hedgehog (Shh) and the transcriptional activator Gli1 (the downstream target of active Hedgehog signaling) were assessed histologically and by immunohistochemistry, respectively. RESULTS Indwelling ureteral stents were found to abolish normal ureteral function in all animals. Specifically, ureteral smooth muscle (SM) activity was significantly diminished within 48 hours after stenting and persisted at the 1-week time point. Furthermore, ureteral SM dysfunction was associated with increasing ureteral dilation due to the indwelling stent. Simultaneously, we observed a loss of Gli1 expression in SM cells, with a concomitant increase in ureteral inflammation. Expression of Shh was restricted to the urothelium and was not different between controls, stented, and contralateral ureters. CONCLUSION Stent-induced aperistalsis was associated with diminished SM contractility, increased tissue inflammation, and reduced Gli1 expression in ureteral SM cells, independent of Shh expression. The present study is the first to show that indwelling stents negatively affect ureteral SM activity and identify a role for specific molecular mechanisms involved.
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Affiliation(s)
- Claudia Janssen
- Department of Urologic Sciences, The Stone Centre at Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada; Department of Urology, Johannes Gutenberg University, Mainz, Germany
| | - Ralph Buttyan
- Department of Urologic Sciences, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada
| | - Chun Y Seow
- Department of Pathology and Laboratory Medicine, James Hogg Research Centre, St. Paul Hospital/Providence Health Care, University of British Columbia, Vancouver, BC, Canada
| | - Wolfgang Jäger
- Department of Urology, Johannes Gutenberg University, Mainz, Germany; Department of Urologic Sciences, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada
| | - Dennis Solomon
- Department of Pathology and Laboratory Medicine, James Hogg Research Centre, St. Paul Hospital/Providence Health Care, University of British Columbia, Vancouver, BC, Canada
| | - Ladan Fazli
- Department of Urologic Sciences, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada
| | - Ben H Chew
- Department of Urologic Sciences, The Stone Centre at Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada
| | - Dirk Lange
- Department of Urologic Sciences, The Stone Centre at Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.
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Hashitani H, Nguyen MJ, Noda H, Mitsui R, Higashi R, Ohta K, Nakamura KI, Lang RJ. Interstitial cell modulation of pyeloureteric peristalsis in the mouse renal pelvis examined using FIBSEM tomography and calcium indicators. Pflugers Arch 2017; 469:797-813. [PMID: 28054154 DOI: 10.1007/s00424-016-1930-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 12/12/2016] [Indexed: 12/28/2022]
Abstract
Typical and atypical smooth muscle cells (TSMCs and ASMCs, respectively) and interstitial cells (ICs) within the pacemaker region of the mouse renal pelvis were examined using focused ion beam scanning electron (FIB SEM) tomography, immunohistochemistry and Ca2+ imaging. Individual cells within 500-900 electron micrograph stacks were volume rendered and associations with their neighbours established. 'Ribbon-shaped', Ano1 Cl- channel immuno-reactive ICs were present in the adventitia and the sub-urothelial space adjacent to the TSMC layer. ICs in the proximal renal pelvis were immuno-reactive to antibodies for CaV3.1 and hyperpolarization-activated cation nucleotide-gated isoform 3 (HCN3) channel sub-units, while basal-epithelial cells (BECs) were intensely immuno-reactive to Kv7.5 channel antibodies. Adventitial to the TSMC layer, ASMCs formed close appositions with TSMCs and ICs. The T-type Ca2+channel blocker, Ni2+ (10-200 μM), reduced the frequency while the L-type Ca2+ channel blocker (1 μM nifedipine) reduced the amplitude of propagating Ca2+ waves and contractions in the TSMC layer. Upon complete suppression of Ca2+ entry through TSMC Ca2+ channels, ASMCs displayed high-frequency (6 min-1) Ca2+ transients, and ICs distributed into two populations of cells firing at 1 and 3 min-1, respectively. IC Ca2+ transients periodically (every 3-5 min-1) summed into bursts which doubled the frequency of ASMC Ca2+ transient firing. Synchronized IC bursting and the acceleration of ASMC firing were inhibited upon blockade of HCN channels with ZD7288 or cell-to-cell coupling with carbenoxolone. While ASMCs appear to be the primary pacemaker driving pyeloureteric peristalsis, it was concluded that sub-urothelial HCN3(+), CaV3.1(+) ICs can accelerate ASMC Ca2+ signalling.
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Affiliation(s)
- Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, 467-8601, Japan
| | - Michael J Nguyen
- Department of Pharmacology, School of Biomedical Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Haruka Noda
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, 467-8601, Japan
| | - Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, 467-8601, Japan
| | - Ryuhei Higashi
- Department of Anatomy, Kurume University School of Medicine, Kurume, Japan
| | - Keisuke Ohta
- Department of Anatomy, Kurume University School of Medicine, Kurume, Japan
| | | | - Richard J Lang
- Department of Pharmacology, School of Biomedical Sciences, Monash University, Clayton, VIC, 3800, Australia.
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Nguyen M, Higashi R, Ohta K, Nakamura KI, Hashitani H, Lang R. Autonomic and sensory nerve modulation of peristalsis in the upper urinary tract. Auton Neurosci 2016; 200:1-10. [DOI: 10.1016/j.autneu.2015.07.425] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 07/20/2015] [Accepted: 07/28/2015] [Indexed: 11/24/2022]
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Steinbach A, Schaper K, Koenen A, Schlüter T, Zimmermann U, Rettig R, Grisk O. Role of endothelin-1 for the regulation of renal pelvic function. Pflugers Arch 2016; 468:1467-78. [DOI: 10.1007/s00424-016-1848-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/17/2016] [Accepted: 06/06/2016] [Indexed: 10/21/2022]
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Nguyen MJ, Hashitani H, Lang RJ. Angiotensin receptor-1A knockout leads to hydronephrosis not associated with a loss of pyeloureteric peristalsis in the mouse renal pelvis. Clin Exp Pharmacol Physiol 2016; 43:535-42. [DOI: 10.1111/1440-1681.12560] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 02/07/2016] [Accepted: 02/09/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Michael J Nguyen
- Department of Physiology; School of Biomedical Sciences; Monash University; Clayton Victoria Australia
| | - Hikaru Hashitani
- Department of Cell Physiology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Richard J Lang
- Department of Physiology; School of Biomedical Sciences; Monash University; Clayton Victoria Australia
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12
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Koenen A, Steinbach A, Schaper K, Zimmermann U, Miehe B, Kurt B, Rettig R, Grisk O. Effects of renal denervation on renal pelvic contractions and connexin expression in rats. Acta Physiol (Oxf) 2016; 216:240-53. [PMID: 26436542 DOI: 10.1111/apha.12612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 07/03/2015] [Accepted: 09/26/2015] [Indexed: 12/23/2022]
Abstract
AIMS The renal pelvis shows spontaneous rhythmic contractile activity. We assessed to what extent this activity depends on renal innervation and studied the role of connexins in pelvic contractions. METHODS Rats underwent unilateral renal denervation or renal transplantation. Renal pelvic pressure and diuresis were measured in vivo. Spontaneous and agonist-induced contractions of isolated renal pelves were investigated by wire myography. Rat and human renal pelvic connexin mRNA abundances and connexin localization were studied by real-time PCR and immunofluorescence respectively. RESULTS Renal denervation or transplantation increased renal pelvic pressure in vivo by about 60 and 150%, respectively, but did not significantly affect pelvic contraction frequency. Under in vitro conditions, isolated pelvic preparations from innervated or denervated kidneys showed spontaneous contractions. Pelves from denervated kidneys showed about 50% higher contraction frequencies than pelves from innervated kidneys, whereas contraction force was similar in pelves from denervated and innervated kidneys. There was no denervation-induced supersensitivity to noradrenaline or endothelin-1. Renal denervation did not increase pelvic connexin37, 40, 43 or 45 mRNA abundances. Gap junction blockade had no effect on spontaneous pelvic contractile activity. CONCLUSIONS The denervation-induced effect on pelvic pressure may be the consequence of the enhanced diuresis. The mechanisms underlying the denervation-induced effects on pelvic contraction frequency remain unknown. Our data rule out a major role for two important candidates, by showing that renal denervation neither induced supersensitivity to contractile agonists nor increased connexin mRNA abundance in the pelvic wall.
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Affiliation(s)
- A. Koenen
- Department of Physiology; University of Greifswald; Karlsburg Germany
| | - A. Steinbach
- Department of Physiology; University of Greifswald; Karlsburg Germany
| | - K. Schaper
- Department of Physiology; University of Greifswald; Karlsburg Germany
| | - U. Zimmermann
- Department of Urology; University of Greifswald; Greifswald Germany
| | - B. Miehe
- Departments of Anatomy and Cell Biology; University of Greifswald; Greifswald Germany
| | - B. Kurt
- Department of Physiology; University of Regensburg; Regensburg Germany
| | - R. Rettig
- Department of Physiology; University of Greifswald; Karlsburg Germany
| | - O. Grisk
- Department of Physiology; University of Greifswald; Karlsburg Germany
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Hurtado R, Smith CS. Hyperpolarization-activated cation and T-type calcium ion channel expression in porcine and human renal pacemaker tissues. J Anat 2016; 228:812-25. [PMID: 26805464 DOI: 10.1111/joa.12444] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2015] [Indexed: 02/06/2023] Open
Abstract
Renal pacemaker activity triggers peristaltic upper urinary tract contractions that propel waste from the kidney to the bladder, a process prone to congenital defects that are the leading cause of pediatric kidney failure. Recently, studies have discovered that hyperpolarization-activated cation (HCN) and T-type calcium (TTC) channel conductances underlie murine renal pacemaker activity, setting the origin and frequency and coordinating upper urinary tract peristalsis. Here, we determined whether this ion channel expression is conserved in the porcine and human urinary tracts, which share a distinct multicalyceal anatomy with multiple pacemaker sites. Double chromagenic immunohistochemistry revealed that HCN isoform 3 is highly expressed at the porcine minor calyces, the renal pacemaker tissues, whereas the kidney and urinary tract smooth muscle lacked this HCN expression. Immunofluorescent staining demonstrated that HCN(+) cells are integrated within the porcine calyx smooth muscle, and that they co-express TTC channel isoform Cav3.2. In humans, the anatomic structure of the minor calyx pacemaker was assayed via hematoxylin and eosin analyses, and enabled the visualization of the calyx smooth muscle surrounding adjacent papillae. Strikingly, immunofluorescence revealed that HCN3(+) /Cav3.2(+) cells are also localized to the human minor calyx smooth muscle. Collectively, these data have elucidated a conserved molecular signature of HCN and TTC channel expression in porcine and human calyx pacemaker tissues. These findings provide evidence for the mechanisms that can drive renal pacemaker activity in the multi-calyceal urinary tract, and potential causes of obstructive uropathies.
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Affiliation(s)
- Romulo Hurtado
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, NY, USA.,The Core for Smooth Muscle Analysis, Weill Medical College of Cornell University, New York, NY, USA
| | - Carl S Smith
- Department of Urologic Surgery, University of Minnesota School of Medicine, Minneapolis, MN, USA
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Hickling DR, Sun TT, Wu XR. Anatomy and Physiology of the Urinary Tract: Relation to Host Defense and Microbial Infection. Microbiol Spectr 2015; 3:10.1128/microbiolspec.UTI-0016-2012. [PMID: 26350322 PMCID: PMC4566164 DOI: 10.1128/microbiolspec.uti-0016-2012] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Indexed: 02/07/2023] Open
Abstract
The urinary tract exits to a body surface area that is densely populated by a wide range of microbes. Yet, under most normal circumstances, it is typically considered sterile, i.e., devoid of microbes, a stark contrast to the gastrointestinal and upper respiratory tracts where many commensal and pathogenic microbes call home. Not surprisingly, infection of the urinary tract over a healthy person's lifetime is relatively infrequent, occurring once or twice or not at all for most people. For those who do experience an initial infection, the great majority (70% to 80%) thankfully do not go on to suffer from multiple episodes. This is a far cry from the upper respiratory tract infections, which can afflict an otherwise healthy individual countless times. The fact that urinary tract infections are hard to elicit in experimental animals except with inoculum 3-5 orders of magnitude greater than the colony counts that define an acute urinary infection in humans (105 cfu/ml), also speaks to the robustness of the urinary tract defense. How can the urinary tract be so effective in fending off harmful microbes despite its orifice in a close vicinity to that of the microbe-laden gastrointestinal tract? While a complete picture is still evolving, the general consensus is that the anatomical and physiological integrity of the urinary tract is of paramount importance in maintaining a healthy urinary tract. When this integrity is breached, however, the urinary tract can be at a heightened risk or even recurrent episodes of microbial infections. In fact, recurrent urinary tract infections are a significant cause of morbidity and time lost from work and a major challenge to manage clinically. Additionally, infections of the upper urinary tract often require hospitalization and prolonged antibiotic therapy. In this chapter, we provide an overview of the basic anatomy and physiology of the urinary tract with an emphasis on their specific roles in host defense. We also highlight the important structural and functional abnormalities that predispose the urinary tract to microbial infections.
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Affiliation(s)
- Duane R Hickling
- Division of Urology, Ottawa Hospital Research Institute, The Ottawa Hospital, University of Ottawa, Ottawa, ON K1Y 4E9, Canada
| | - Tung-Tien Sun
- Departments of Cell Biology, Biochemistry and Molecular Pharmacology, Departments of Dermatology and Urology, New York University School of Medicine, New York, NY, 10016
| | - Xue-Ru Wu
- Departments of Urology and Pathology, New York University School of Medicine, New York, NY, 10016
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15
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Ureter growth and differentiation. Semin Cell Dev Biol 2014; 36:21-30. [DOI: 10.1016/j.semcdb.2014.07.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/22/2014] [Accepted: 07/22/2014] [Indexed: 12/25/2022]
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16
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Nguyen MJ, Angkawaijawa S, Hashitani H, Lang RJ. Nicotinic receptor activation on primary sensory afferents modulates autorhythmicity in the mouse renal pelvis. Br J Pharmacol 2014; 170:1221-32. [PMID: 24004375 DOI: 10.1111/bph.12395] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Revised: 08/19/2013] [Accepted: 08/27/2013] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The modulation of the spontaneous electrical and Ca(2+) signals underlying pyeloureteric peristalsis upon nicotinic receptor activation located on primary sensory afferents (PSAs) was investigated in the mouse renal pelvis. EXPERIMENTAL APPROACH Contractile activity was followed using video microscopy, electrical and Ca(2+) signals in typical and atypical smooth muscle cells (TSMCs and ASMCs) within the renal pelvis were recorded separately using intracellular microelectrodes and Fluo-4 Ca(2+) imaging. KEY RESULTS Nicotine and carbachol (CCh; 1-100 μM) transiently reduced the frequency and increased the amplitude of spontaneous phasic contractions in a manner unaffected by muscarininc antagonists, 4-DAMP (1,1-dimethyl-4-diphenylacetoxypiperidinium iodide) and pirenzipine (10 nM) or L-NAME (L-Nω-nitroarginine methyl ester; 200 μM), inhibitor of NO synthesis, but blocked by the nicotinic antagonist, hexamethonium or capsaicin, depletor of PSA neuropeptides. These negative chronotropic and delayed positive inotropic effects of CCh on TSMC contractions, action potentials and Ca(2+) transients were inhibited by glibenclamide (Glib; 1 μM), blocker of ATP-dependent K (KATP) channels. Nicotinic receptor-evoked inhibition of the spontaneous Ca(2+) transients in ASMCs was prevented by capsaicin but not Glib. In contrast, the negative inotropic and chronotropic effects of the non-selective COX inhibitor indomethacin were not prevented by Glib. CONCLUSIONS AND IMPLICATIONS The negative chronotropic effect of nicotinic receptor activation results from the release of calcitonin gene-related peptide (CGRP) from PSAs, which suppresses Ca(2+) signalling in ASMCs. PSA-released CGRP also evokes a transient hyperpolarization in TSMCs upon the opening of KATP channels, which reduces contraction propagation but promotes the recruitment of TSMC Ca(2+) channels that underlie the delayed positive inotropic effects of CCh.
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Affiliation(s)
- M J Nguyen
- Department of Physiology, School of Biomedical Sciences, Monash University, Clayton, Vic., Australia
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17
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Calcium signalling in Cajal-like interstitial cells of the lower urinary tract. Nat Rev Urol 2014; 11:555-64. [PMID: 25224445 DOI: 10.1038/nrurol.2014.241] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Interstitial cells of Cajal (ICC) serve several critical physiological roles in visceral smooth muscle organs, including acting as electrical pacemakers to modulate phasic contractile activity and as intermediaries in motor neurotransmission. The major roles of ICC have been described in the gastrointestinal tract, however, ICC-like cells (ICC-LC) can also be found in other visceral organs, including those of the lower urinary tract (LUT), where they provide similar functions, acting as electrical pacemakers and as intermediary cells involved in the modulation of neurotransmission to adjacent smooth muscle cells. The physiological functions of ICC-LC, in particular their role as pacemakers, relies on their ability to generate transient and propagating intracellular Ca(2+) events. The role of ICC-LC as pacemakers and neuromodulators in the LUT is increasingly apparent and the study of their intracellular Ca(2+) dynamics will provide a better understanding of their role in LUT excitability.
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18
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Sanders KM, Ward SM, Koh SD. Interstitial cells: regulators of smooth muscle function. Physiol Rev 2014; 94:859-907. [PMID: 24987007 DOI: 10.1152/physrev.00037.2013] [Citation(s) in RCA: 313] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Smooth muscles are complex tissues containing a variety of cells in addition to muscle cells. Interstitial cells of mesenchymal origin interact with and form electrical connectivity with smooth muscle cells in many organs, and these cells provide important regulatory functions. For example, in the gastrointestinal tract, interstitial cells of Cajal (ICC) and PDGFRα(+) cells have been described, in detail, and represent distinct classes of cells with unique ultrastructure, molecular phenotypes, and functions. Smooth muscle cells are electrically coupled to ICC and PDGFRα(+) cells, forming an integrated unit called the SIP syncytium. SIP cells express a variety of receptors and ion channels, and conductance changes in any type of SIP cell affect the excitability and responses of the syncytium. SIP cells are known to provide pacemaker activity, propagation pathways for slow waves, transduction of inputs from motor neurons, and mechanosensitivity. Loss of interstitial cells has been associated with motor disorders of the gut. Interstitial cells are also found in a variety of other smooth muscles; however, in most cases, the physiological and pathophysiological roles for these cells have not been clearly defined. This review describes structural, functional, and molecular features of interstitial cells and discusses their contributions in determining the behaviors of smooth muscle tissues.
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Affiliation(s)
- Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Sang Don Koh
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
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Abstract
Urine differs greatly in ion and solute composition from plasma and contains harmful and noxious substances that must be stored for hours and then eliminated when it is socially convenient to do so. The urinary tract that handles this output is composed of a series of pressurizable muscular compartments separated by sphincteric structures. With neural input, these structures coordinate the delivery, collection, and, ultimately, expulsion of urine. Despite large osmotic and chemical gradients in this waste fluid, the bladder maintains a highly impermeable surface in the face of a physically demanding biomechanical environment, which mandates recurring cycles of surface area expansion and increased wall tension during filling, followed by rapid wall compression during voiding. Afferent neuronal inflow from mucosa and submucosa communicates sensory information about bladder fullness, and voiding is initiated consciously through coordinated central and spinal efferent outflow to the detrusor, trigonal internal sphincter, and external urethral sphincter after periods of relative quiescence. Provocative new findings suggest that in some cases, lower urinary tract symptoms, such as incontinence, urgency, frequency, overactivity, and pain may be viewed as a consequence of urothelial defects (either urothelial barrier breakdown or inappropriate signaling from urothelial cells to underlying sensory afferents and potentially interstitial cells). This review describes the physiologic and anatomic mechanisms by which urine is moved from the kidney to the bladder, stored, and then released. Relevant clinical examples of urinary tract dysfunction are also discussed.
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Affiliation(s)
- Warren G Hill
- Laboratory of Voiding Dysfunction, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
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20
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Hurtado R, Bub G, Herzlinger D. A molecular signature of tissues with pacemaker activity in the heart and upper urinary tract involves coexpressed hyperpolarization-activated cation and T-type Ca2+ channels. FASEB J 2013; 28:730-9. [PMID: 24189942 DOI: 10.1096/fj.13-237289] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Renal pacemakers set the origin and frequency of the smooth muscle contractions that propel wastes from the kidney to the bladder. Although congenital defects impairing this peristalsis are a leading cause of pediatric renal failure, the mechanisms underlying renal pacemaker activity remain unknown. Using ratiometric optical mapping and video microscopy, we discovered that hyperpolarization-activated cation (HCN) channel block with the specific anatagonist ZD7288 (30 μm; IC50) abolished the pacemaker depolarizations that initiate murine upper urinary tract peristalsis. Optical mapping and immunohistochemistry indicate that pacemaker potentials are generated by cells expressing HCN isoform-3, and that HCN3(+) cells are coupled to definitive smooth muscle via gap junctions. Furthermore, we demonstrate that HCN3(+) cells coexpress T-type Ca(2+) (TTC) channels and that TTC channel inhibition with R(-)efonidipine or NNC55-0396 decreased contractile frequency in a dose-dependent manner. Collectively, these data demonstrate that HCN3(+)/TTC(+) cells are the pacemakers that set the origin and rate of upper urinary tract peristalsis. These results reveal a conserved mechanism controlling autorhythmicity in 2 distinct muscle types, as HCN and TTC channels also mediate cardiac pacemaker activity. Moreover, these findings have translational applications, including the development of novel diagnostics to detect fetal urinary tract motility defects prior to renal damage.-Hurtado, R., Bub, G., Herzlinger, D. A molecular signature of tissues with pacemaker activity in the heart and upper urinary tract involves coexpressed hyperpolarization-activated cation and T-type Ca(2+) channels.
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Affiliation(s)
- Romulo Hurtado
- 1Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, NY 10021, USA.
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21
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Rasouly HM, Lu W. Lower urinary tract development and disease. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2013; 5:307-42. [PMID: 23408557 PMCID: PMC3627353 DOI: 10.1002/wsbm.1212] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Congenital anomalies of the lower urinary tract (CALUT) are a family of birth defects of the ureter, the bladder, and the urethra. CALUT includes ureteral anomaliesc such as congenital abnormalities of the ureteropelvic junction (UPJ) and ureterovesical junction (UVJ), and birth defects of the bladder and the urethra such as bladder-exstrophy-epispadias complex (BEEC), prune belly syndrome (PBS), and posterior urethral valves (PUVs). CALUT is one of the most common birth defects and is often associated with antenatal hydronephrosis, vesicoureteral reflux (VUR), urinary tract obstruction, urinary tract infections (UTI), chronic kidney disease, and renal failure in children. Here, we discuss the current genetic and molecular knowledge about lower urinary tract development and genetic basis of CALUT in both human and mouse models. We provide an overview of the developmental processes leading to the formation of the ureter, the bladder, and the urethra, and different genes and signaling pathways controlling these developmental processes. Human genetic disorders that affect the ureter, the bladder and the urethra and associated gene mutations are also presented. As we are entering the postgenomic era of personalized medicine, information in this article may provide useful interpretation for the genetic and genomic test results collected from patients with lower urinary tract birth defects. With evidence-based interpretations, clinicians may provide more effective personalized therapies to patients and genetic counseling for their families.
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Affiliation(s)
- Hila Milo Rasouly
- Renal Section, Department of Medicine, Boston University Medical Center, Boston, MA 02118, USA
| | - Weining Lu
- Renal Section, Department of Medicine, Boston University Medical Center, Boston, MA 02118, USA
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22
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McCloskey KD. Bladder interstitial cells: an updated review of current knowledge. Acta Physiol (Oxf) 2013; 207:7-15. [PMID: 23034074 DOI: 10.1111/apha.12009] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 01/22/2012] [Accepted: 09/10/2012] [Indexed: 01/12/2023]
Abstract
The field of bladder research has been energized by the study of novel interstitial cells (IC) over the last decade. Several subgroups of IC are located within the bladder wall and make structural interactions with nerves and smooth muscle, indicating integration with intercellular communication and key physiological functions. Significant progress has been made in the study of bladder ICs' cellular markers, ion channels and receptor expression, electrical and calcium signalling, yet their specific functions in normal bladder filling and emptying remain elusive. There is increasing evidence that the distribution of IC is altered in bladder pathophysiologies suggesting that changes in IC may be linked with the development of bladder dysfunction. This article summarizes the current state of the art of our knowledge of IC in normal bladder and reviews the literature on IC in dysfunctional bladder.
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Affiliation(s)
- K. D. McCloskey
- Centre for Cancer Research and Cell Biology; Queen's University Belfast; Belfast; Northern Ireland; UK
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23
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Iqbal J, Tonta MA, Mitsui R, Li Q, Kett M, Li J, Parkington HC, Hashitani H, Lang RJ. Potassium and ANO1/ TMEM16A chloride channel profiles distinguish atypical and typical smooth muscle cells from interstitial cells in the mouse renal pelvis. Br J Pharmacol 2012; 165:2389-408. [PMID: 22014103 DOI: 10.1111/j.1476-5381.2011.01730.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Although atypical smooth muscle cells (SMCs) in the proximal renal pelvis are thought to generate the pacemaker signals that drive pyeloureteric peristalsis, their location and electrical properties remain obscure. EXPERIMENTAL APPROACH Standard patch clamp, intracellular microelectrode and immunohistochemistry techniques were used. To unequivocally identify SMCs, transgenic mice with enhanced yellow fluorescent protein (eYFP) expressed in cells containing α-smooth muscle actin (α-SMA) were sometimes used. KEY RESULTS Atypical SMCs were distinguished from typical SMCs by the absence of both a transient 4-aminopyridine-sensitive K(+) current (I(KA) ) and spontaneous transient outward currents (STOCs) upon the opening of large-conductance Ca(2+) -activated K(+) (BK) channels. Many typical SMCs displayed a slowly activating, slowly decaying Cl(-) current blocked by niflumic acid (NFA). Immunostaining for K(V) 4.3 and ANO1/ TMEM16A Cl(-) channel subunits co-localized with α-SMA immunoreactive product predominately in the distal renal pelvis. Atypical SMCs fired spontaneous inward currents that were either selective for Cl(-) and blocked by NFA, or cation-selective and blocked by La(3+) . α-SMA(-) interstitial cells (ICs) were distinguished by the presence of a Xe991-sensitive K(V) 7 current, BK channel STOCs and Cl(-) selective, NFA-sensitive spontaneous transient inward currents (STICs). Intense ANO1/ TMEM16A and K(V) 7.5 immunostaining was present in Kit(-) α-SMA(-) ICs in the suburothelial and adventitial regions of the renal pelvis. CONCLUSIONS AND IMPLICATIONS We conclude that K(V) 4.3(+) α-SMA(+) SMCs are typical SMCs that facilitate muscle wall contraction, that ANO1/ TMEM16A and K(V) 7.5 immunoreactivity may be selective markers of Kit(-) ICs and that atypical SMCs which discharge spontaneous inward currents are the pelviureteric pacemakers.
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Affiliation(s)
- Javed Iqbal
- Department of Physiology Anatomy & Development Biology, Monash University, Clayton, Victoria, Australia
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24
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Abstract
The study of novel interstitial cells in the tissues of the urinary tract has defined advances in the field in the last decade. These intriguing cells belong to the same family as the better known interstitial cells of Cajal (ICC) of the gastrointestinal tract, and their discovery has been interpreted to suggest that pacemaker cells may be present in the urinary tract, driving the spontaneous or myogenic activity of the neighboring smooth muscle. This scenario may be true for the urethra where ICC have been described as "loose pacemakers" providing multiple, random inputs to modulate urethral smooth muscle activity. However, there is a paucity of direct evidence available to support this hypothesis in the bladder (where the smooth muscle cells are spontaneously active) or the renal pelvis (where atypical smooth muscle cells are the pacemakers), and it now seems more likely that urinary tract ICC act as modulators of smooth muscle activity.Interestingly, the literature suggests that the role of urinary tract ICC may be more apparent in pathophysiological conditions such as the overactive bladder. Several reports have indicated that the numbers of ICC present in overactive bladder tissues are greater than those from normal tissues; moreover, the contractility of tissues from overactive bladders in vitro appears to be more sensitive to the Kit antagonist, glivec, than those from normal bladder. Future research on urinary tract ICC in the short to medium term is likely to be dynamic and exciting and will lead to increasing our understanding of the roles of these cells in both normal and dysfunctional bladder.
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Affiliation(s)
- Karen D McCloskey
- School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK.
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25
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Abstract
Interstitial cells of Cajal (ICC)-like cells (ICC-LCs) have been identified in many regions of the urinary tract and male genital organs by immunohistochemical studies and electron microscopy. ICC-LCs are characterized by their spontaneous electrical and Ca2+ signalling and the cellular mechanisms of their generation have been extensively investigated. Spontaneous activity in ICC-LCs rises from the release of internally stored Ca2+ and the opening of Ca2+-activated Cl− channels to generate spontaneous transient depolarizations (STDs) in a manner not fundamentally dependent on Ca2+ influx through L-type voltage-dependent Ca2+ channels. Since urogenital ICC-LCs have been identified by their immunoreactivity to Kit (CD117) antibodies, the often-used specific marker for ICC in the gastrointestinal tract, their functions have been thought likely to be similar. Thus ICC-LCs in the urogenital tract might be expected to act as either electrical pacemaker cells to drive the smooth muscle wall or as intermediaries in neuromuscular transmission. However, present knowledge of the functions of ICC-LCs suggests that their functions are not so predetermined, that their functions may be very region specific, particularly under pathological conditions. In this review, we summarize recent advances in our understanding of the location and function of ICC-LCs in various organs of the urogenital system. We also discuss several unsolved issues regarding the identification, properties and functions of ICC-LCs in various urogenital regions in health and disease.
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Affiliation(s)
- Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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Hurtado R, Bub G, Herzlinger D. The pelvis-kidney junction contains HCN3, a hyperpolarization-activated cation channel that triggers ureter peristalsis. Kidney Int 2009; 77:500-8. [PMID: 20032965 DOI: 10.1038/ki.2009.483] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Peristaltic waves of the ureteric smooth muscles move urine down from the kidney, a process that is commonly defective in congenital diseases. To study the mechanisms that control the initiation and direction of contractions, we used video microscopy and optical mapping techniques and found that electrical and contractile waves began in a region where the renal pelvis joined the connective tissue core of the kidney. Separation of this pelvis-kidney junction from more distal urinary tract segments prevented downstream peristalsis, indicating that it housed the trigger for peristalsis. Moreover, cells in the pelvis-kidney junction were found to express isoform 3 of the hyperpolarization-activated cation on channel family known to be required for initiating electrical activity in the brain and heart. Immunocytochemical and real-time PCR analyses found that hyperpolarization-activated cation-3 is expressed at the pelvis-kidney junction where electrical excitation and contractile waves originate. Inhibition of this channel caused a loss of electrical activity at the pelvis-kidney junction and randomized the origin of electrical activity in the urinary tract, thus markedly perturbing contractions. Collectively, our study demonstrates that hyperpolarization-activated cation-3 channels play a fundamental role in coordinating proximal-to-distal peristalsis of the upper urinary tract. This provides insight into the genetic causes of common inherited urinary tract disorders such as reflux and obstruction.
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Affiliation(s)
- Romulo Hurtado
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, New York 10021, USA
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